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)

Analysis Ratio of Uranyl/Urea and Uranyl/HMTA on the ComplexesUranyl-Urea and Uranyl-HMTA with Spectrophotometry Method

International Nuclear Information System (INIS)

Simbolon, Sahat

2000-01-01

Reaction between uranyl and urea and uranyl and HMTA was investigated atpH = 4 and room temperature. The result of the reaction was measured withspectrophotometer, each absorbance was pictured between mol fraction andabsorbance for uranyl - urea and uranyl - HMTA. The linear and horizontalcurve was found for reaction uranyl - urea, meanwhile S curve for thereaction uranyl and HMTA. It was found that reaction between uranyl and HMTAon mol fraction value less than 0.25 was complexes meanwhile on the range of0.25 and 0.5 the reaction between uranyl and HMTA was stoichiometries.(author)

Physico-chemical study of new functionalized surfactants having thermo sensitive de-mixing behaviour: use in extraction of uranyl nitrate

International Nuclear Information System (INIS)

Prevost, S.

2006-04-01

New thermo-sensitive functionalized surfactants with metal-chelating properties have been developed and their physical-chemistry studied. They associate a polyethoxylated nonionic surfactant (CiEj) block and a amino-acid residue as a chelating group. Functionalization preserves both properties of the thermo-sensitive surfactant moiety and the chelating group, a diamide closed to uranyl ionophore.The complexing group participates to the polar head group of the surfactant, increasing the area per molecule. As a result, functionalized surfactants form spherical micelles when diluted in water, and the concentrated part of their phase diagrams exhibits structures having higher curvatures than the nonionic precursor CiEj. The structure of the uranyl - diamide complex has been elucidated by NMR and ESI-MS and is of the type UO 2 (NO 3 ) 2 .L; the associated complexation constant, which is very low, has been evaluated by 1 H NMR.A nitrate salt, LiNO 3 , is added at high concentration to improve complexation. The effect of this salt has been analyzed, and was found to be rather similar to the effect on classical CiEj. When uranyl nitrate complexation occurs, the cloud point decreases dramatically, together with the reduction of the area per head group at micelle/solution interface. This effect can be minimized by using a nonionic precursor having a larger polar head group. The functionalized surfactants have been tested in the cloud point extraction of uranyl nitrate, and have proved their efficiency. Those results demonstrate the viability of the functionalized surfactants design, with a covalent link between a thermo-sensitive surfactant block and a chelating group. (author)

Labeling of monoclonal antibodies with a 67Ga-phenolic aminocarboxylic acid chelate. Part II. Comparison of immunoreactivity and biodistribution of monoclonal antibodies labeled with the 67Ga-chelate or with 131I.

Science.gov (United States)

Matzku, S; Schuhmacher, J; Kirchgessner, H; Brüggen, J

1986-01-01

Coupling of the 67Ga-P-EDDHA chelate via carbodiimide to the anti-melanoma monoclonal antibody (Mab) M.2.9.4 resulted in a low degree of oligomerization, but a considerable degree of intra-molecular (inter-chain) cross-linking. However, this did not impair immunoreactivity, nor did the half-life in vivo differ substantially from that of 131I-M.2.9.4. Biodistribution analysis in normal mice showed Ga:I ratios near 1 in the blood and other tissues not involved in degradation and label excretion. In tissues of the reticulo-endothelial system (RES) and the kidneys, Ga:I ratios up to 2.51 were reached within 4 days of administration. In antigen-positive MeWo tumor tissue, retention of 67Ga also excreted that of 131I, so that tumor; organ ratios (except tumor:liver) were superior for the 67Ga-labeled MAb. It is concluded that the method of coupling pre-established 67Ga-P-EDDHA chelate to antibody results in a functionally intact tracer molecule, whose persistence in vivo is not significantly impaired. The major difference to I-labeled MAbs may be a prolonged retention of Ga in tissues (cells) physiologically involved in antibody catabolism.

Labeling of monoclonal antibodies with a 67Ga phenolic aminocarboxylic acid chelate. Pt. 2

International Nuclear Information System (INIS)

Matzku, S.; Schuhmacher, J.; Kirchgessner, H.; Brueggen, J.

1986-01-01

Coupling of the 67 Ga-P-EDDHA chelate via carbodiimide to the anti-melanoma monoclonal antibody (MAb) M.2.9.4 resulted in a low degree of oligomerization, but a considerable degree of intra-molecular (inter-chain) cross-linking. However, this did not impair immunoreactivity, nor did the half-life in vivo differ substantially from that of 131 I-M.2.9.4. Biodistribution analysis in normal mice showed Ga:I ratios near 1 in the blood and other tissues not involved in degradation and label excretion. In tissues of the reticulo-endothelial system (RES) and the kidneys, Ga:I ratios up to 2.51 were reached within 4 days of administration. In antigen-positive MeWo tumor tissue, retention of 67 Ga also exceeded that of 131 I, so that tumor : organ ratios (except tumor : liver) were superior for the 67 Ga-labeled MAb. It is concluded that the method of coupling pre-established 67 Ga-P-EDDHA chelate to antibody, results in a functionally intact tracer molecule, whose persistence in vivo is not significantly impaired. The major difference to I-labeled MAbs may be prolonged retention of Ga in tissues (cells) physiologically involved in antibody catabolism. (orig.)

Comparative studies of 111In-labeled monoclonal antibody using spacer-containing and non-spacer bifunctional chelates. 2

International Nuclear Information System (INIS)

Sun, Baofu

1994-01-01

Indium-111-labeled A7 monoclonal antibodies using two spacer-containing chelates, succinimido-EGS-DTPA (EGS-DTPA: diester spacer) and maleimido-C10-Bz-EDTA (C10-Bz-EDTA: hydrocarbon spacer) were investigated in human LS180 colon tumor bearing nude mice and were compared with two non-spacer chelates, cyclic DTPA dianhydride (cDTPAA) and isothiocyanatobenzyl-EDTA (SCN-Bz-EDTA). Compared with immunoconjugates using non-spacer chelates, immunoconjugates using spacer-containing chelates, especially C10-Bz-EDTA-A7 showed lower 111 In activity in normal organs. The radioactivity in the liver for C10-Bz-EDTA-A7 decreased continuously till 96 hrs postinjection, however, this liver radioactivity for EGS-DTPA-A7 showed little change after 24 hrs. Moreover, in liver subcellular distribution study, EGS-DTPA-A7 showed a higher activity retention in mitochondrial fraction which contained lysosome, a place for metabolizing and storing of 111 In labeled antibody, than that of C10-Bz-EDTA-A7. The C10-Bz-EDTA-A7 conjugate demonstrated more preferable tumor-to-non tumor contrast on the scintigrams than that found with other three immunoconjugates. Up to 96 hrs postinjection, tumor bearing nude mice injecting with immunoconjugates using spacer-containing chelates exreted twice radioactivity from whole body than that excreted by using non-spacer chelates. Interestingly, different from other three chelates, C10-Bz-EDTA-A7 were mainly excreted via feces. We conclude that the decrease of radioactivity in normal tissues in the case of EGS-DTPA-A7 was due to the rapid decrease of activity in the blood, while in the case of C10-Bz-EDTA-A7 it was due to the quickly excreted small metabolite through faces. 111 In labeled C10-Bz-EDTA conjugate is superior, at least when conjugated with A7, to other three chelate conjugates used in this study. (author)

Complexes of vanadyl and uranyl ions with the chelating groups of humic matter

International Nuclear Information System (INIS)

Goncalves, M.L.S.; Mota, A.M.

1987-01-01

The uranyl and vanadyl complexes formed with salicylic, phthalic and 3,4-dihydroxybenzoic acids have been studied by potentiometry in order to determine the stability constants of the Msub(m) Lsub(n) species formed in solution, and the constants for hydrolysis and polymeric complexes, at 25.0 0 , in 0.10, 0.40 and 0.70M sodium perchlorate. MINIQUAD was used in process the data to find the best models for the species in solution, and calculate the formation constants. The uranyl-salicylic acid sytem was also studied by spectrophotometry and the program SQUAD used to process the data obtained. The best models for these systems show that co-ordination of the uranyl ion by carboxylate groups is easier than for the vanadyl ion, whereas the vanadyl ion seems to form more stable complexes with phenolate groups. Both oxo-cations seem to tend to hydrolyse rather than form complexes when the L:M ratios are greater than unity. Although the change in the constants with ionic strength is small, the activity coefficients of the salicylate and phthalate species have been calculated at ionic strengths 0.40 and 0.70M, along with the interaction parameters with Na + , from the stability constants found for the species ML and H 2 L, according to the Bronsted-Guggenheim expression. (author)

Reactivity of uranyl ion with quinquedentate chelating hydrazine derivatives. Pt. 2. 2,6-diacetylpyridine bis(4-methoxybenzoylhydrazone)

Energy Technology Data Exchange (ETDEWEB)

Paolucci, G; Marangoni, G; Bandoli, G; Clemente, D A [Consiglio Nazionale delle Ricerche, Padua (Italy). Lab. di Chimica e Tecnologia dei Radioelementi

1980-01-01

The new quinquedentate chelating ligand 2,6-diacetylpyridine bis(4-methoxybenzoylhydrazone) (H/sub 2/dapmb) reacts with uranyl nitrate and perchlorate to give complexes which are described. All the complexes have been fully deprotonated to neutral species (UO/sub 2/(dapmb)), under a range of experimental conditions. This complex can be isolated in two different crystalline forms, ..cap alpha.. and ..beta.., depending on the experimental conditions. All the species have been characterized by a number of analytical and physico-chemical measurements, including the determination of the crystal structure of the two isomers of (UO/sub 2/(dapmb)). An accurate structure determination was carried out for the monoclinic modification, while the investigation of the orthorhombic form was undertaken merely to ascertain whether or not its configuration was the same as that of the monoclinic form. The geometry of (UO/sub 2/(dapmb)) in the two forms is very similar, the only significant difference being the conformation of a carbon atom in a methoxy-group. Seven-fold coordination of U/sup VI/ was found, with the five donor atoms in the equatorial plane and the linear UO/sub 2/ group normal to the plane. Interconversion reactions on the various compounds have been studied.

Labeling of antibodies with a 67Ga-phenolic aminocarboxylic acid chelate. Pt. 1

International Nuclear Information System (INIS)

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

1986-01-01

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 67 Ga, was synthetized. The 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 67 Ga. In vitro stability was evaluated in human serum at 37 0 C and showed a half-life of about 120 h for the release of 67 Ga from the labeled Ab during the initial phase of incubation. This in vitro halflife is similar to that measured for 111 In-DTPA labeled Abs. Because of the high stability of the 67 Ga-P-EDDHA chelate, the in vivo formation of radioactive lebeled transferrin by transchelation, as described for 111 In-DTPA labeled Abs, should, however, be reduced by this labeling technique. (orig.)

Labeling of monoclonal antibodies with a /sup 67/Ga phenolic aminocarboxylic acid chelate. Pt. 2. Comparison of immunoreactivity and biodistribution of monoclonal antibodies labeled with the /sup 67/Ga chelate or with /sup 131/I

Energy Technology Data Exchange (ETDEWEB)

Matzku, S.; Schuhmacher, J.; Kirchgessner, H.; Brueggen, J.

1986-11-01

Coupling of the /sup 67/Ga-P-EDDHA chelate via carbodiimide to the anti-melanoma monoclonal antibody (MAb) M.2.9.4 resulted in a low degree of oligomerization, but a considerable degree of intra-molecular (inter-chain) cross-linking. However, this did not impair immunoreactivity, nor did the half-life in vivo differ substantially from that of /sup 131/I-M.2.9.4. Biodistribution analysis in normal mice showed Ga:I ratios near 1 in the blood and other tissues not involved in degradation and label excretion. In tissues of the reticulo-endothelial system (RES) and the kidneys, Ga:I ratios up to 2.51 were reached within 4 days of administration. In antigen-positive MeWo tumor tissue, retention of /sup 67/Ga also exceeded that of /sup 131/I, so that tumor : organ ratios (except tumor : liver) were superior for the /sup 67/Ga-labeled MAb. It is concluded that the method of coupling pre-established /sup 67/Ga-P-EDDHA chelate to antibody, results in a functionally intact tracer molecule, whose persistence in vivo is not significantly impaired. The major difference to I-labeled MAbs may be prolonged retention of Ga in tissues (cells) physiologically involved in antibody catabolism.

Reaction of uranyl nitrate with carboxylic di-acids under hydrothermal conditions. Crystal structure of complexes with L(+)-tartaric and oxalic acids

International Nuclear Information System (INIS)

Thuery, P.

2007-01-01

L(+)-tartaric acid reacts with uranyl nitrate in the presence of KOH, under mild hydrothermal conditions, to give the complex [UO 2 (C 4 H 4 O 6 )(H 2 O)] (1), the first uranyl tartrate to be crystallographically characterized. Each tartrate ligand bridges three uranyl ions, one of them in chelating fashion through proximal carboxylate and hydroxyl groups. The resulting assemblage is two-dimensional, with the uranyl pentagonal bipyramidal coordination polyhedra separated from one another. Prolonged heating of an uranyl tartrate solution resulted in oxidative cleavage of the acid and formation of the oxalate complex [(UO 2 ) 2 (C 2 O 4 ) 2 (OH)Na(H 2 O) 2 ] (2). The bis-bidentate oxalate and bridging hydroxide groups ensure the formation of sheets with corner-sharing uranyl pentagonal bipyramidal coordination polyhedra, in which six-membered metallacycles encompass the sodium ions. These sheets are assembled into a three-dimensional framework through further oxo-bonding of the sodium ions. (authors)

Beryllium(II), manganese(II) and uranyl(VI)-salicylamide complexes

Energy Technology Data Exchange (ETDEWEB)

Maurya, P L; Agarwala, B V; Dey, A K [Allahabad Univ. (India)

1977-01-01

The preparation, composition, general properties and i.r. absorption spectra of the solid chelates formed by salicylamide with beryllium(II), manganese(II) and uranyl(VI) are described. The complexes have been synthesized by refluxing a mixture of ethanolic solutions of the reactants (metal:ligand :: 1:2) for several hours in the presence of alkali. Attempts to isolate the complexes by the interaction of ethanolic solutions of the metal salts and the ligand in the absence of alkali did not succeed.

Preparation and physicochemical characterization of anionic uranyl. beta. -ketoenolates

Energy Technology Data Exchange (ETDEWEB)

Marangoni, G; Paolucci, G [Consiglio Nazionale delle Ricerche, Padua (Italy). Lab. di Chimica e Tecnologia dei Radioelementi; Graziani, R; Celon, E

1978-01-01

New classes of anionic uranyl ..beta..-ketoenolates of formula (UO/sub 2/L/sub 2/X)/sup -/ (where L = 1,3-diphenylpropane-1,3-dionate (dppd), 4,4,4-trifluoro-1-phenylbutane-1,3-dionate (tfpbd), or 1-phenylbutane-1,3-dionate (pbd); X = Cl/sup -/, Br/sup -/, I/sup -/, (NO/sub 3/)/sup -/, (O/sub 2/CMe)/sup -/, or (NCS)/sup -/) and (L/sub 2/O/sub 2/U(..mu..-X) UO/sub 2/L/sub 2/)/sup -/ (where X = F/sup -/, and also Cl/sup -/ only in the case of L = dppd) have been synthesized and characterized by a number of physical measurements. The different ability of the various anionic ligands to enter into the co-ordination sphere of the uranyl ion, their potentially different bonding modes, and the possible correlations between physical parameters and the nature of either the chelate substituents or the anionic ligand are discussed.

Effectiveness of chelation therapy with time after acute uranium intoxication

International Nuclear Information System (INIS)

Domingo, J.L.; Ortega, A.; Llobet, J.M.; Corbella, J.

1990-01-01

The effect of increasing the time interval between acute uranium exposure and chelation therapy was studied in male Swiss mice. Gallic acid, 4,5-dihydroxy-1,3- benzenedisulfonic acid (Tiron), diethylenetriaminepentaacetic acid (DTPA), and 5-aminosalicylic acid (5-AS) were administered ip at 0, 0.25, 1, 4, and 24 hr after sc injection of 10 mg/kg of uranyl acetate dihydrate. Chelating agents were given at doses equal to one-fourth of their respective LD50 values. Daily elimination of uranium into urine and feces was determined for 4 days after which time the mice were killed, and the concentration of uranium was measured in kidney, spleen, and bone. The excretion of uranium was especially rapid in the first 24 hr. Treatment with Tiron or gallic acid at 0, 0.25, or 1 hr after uranium exposure significantly increased the total excretion of the metal. In kidney and bone, only administration of Tiron at 0, 0.25, or 1 hr after uranium injection, or gallic acid at 1 hr after uranium exposure significantly reduced tissue uranium concentrations. Treatment at later times (4 to 24 hr) did not increase the total excretion of the metal and did not decrease the tissue uranium concentrations 4 days after uranyl acetate administration. The results show that the length of time before initiating chelation therapy for acute uranium intoxication greatly influences the effectiveness of this therapy

Probing the influence of N-donor capping ligands on supramolecular assembly in molecular uranyl materials

Energy Technology Data Exchange (ETDEWEB)

Carter, Korey P.; Kalaj, Mark; Cahill, Christopher L. [Department of Chemistry, The George Washington University, Washington, DC (United States)

2016-01-15

The syntheses and crystal structures of six new compounds containing the UO{sub 2}{sup 2+} cation, 3,5-dichlorobenzoic acid, and a chelating N-donor [2,2'-bipyridine (bipy), 1,10-phenanthroline (phen), 4,7-dimethyl-1,10-phenanthroline (dimethylphen), 2,2{sup '}:6{sup '},2''-terpyridine (terpy), 4{sup '}-chloro-2,2{sup '}:6{sup '},2''-terpyridine (Cl-terpy), or 2,4,6-tris(2-pyridyl)-s-triazine (TPTZ)] are reported. Single-crystal X-ray diffraction analysis of these materials enabled the exploration of the structural relationship between the benzoic acids and the chelating N-donor as well as providing a platform to evaluate the effects of ligand choice on uranyl hydrolysis and subsequent oligomerization. At an unadjusted pH (ca. 3), a mix of uranyl monomers and dimers are observed, dimer formation resulting from both bridging carboxylate linkers and hydroxo bridges. Assembly by halogen- and hydrogen-bonding interactions as well as π-π interactions was observed depending on the experimental conditions utilized. Further, spectroscopic characterization (both vibrational and luminescence) of complexes 1, 4, and 5 to explore the effects of the electron-donating ability of the capping ligand on the corresponding uranyl luminescence and vibrational spectra suggests that there is a relationship between the observed bathochromic shifts and the electron-donating ability of the capping ligands. (Copyright copyright 2015 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim)

Probing the influence of N-donor capping ligands on supramolecular assembly in molecular uranyl materials

International Nuclear Information System (INIS)

Carter, Korey P.; Kalaj, Mark; Cahill, Christopher L.

2016-01-01

The syntheses and crystal structures of six new compounds containing the UO 2 2+ cation, 3,5-dichlorobenzoic acid, and a chelating N-donor [2,2'-bipyridine (bipy), 1,10-phenanthroline (phen), 4,7-dimethyl-1,10-phenanthroline (dimethylphen), 2,2 ' :6 ' ,2''-terpyridine (terpy), 4 ' -chloro-2,2 ' :6 ' ,2''-terpyridine (Cl-terpy), or 2,4,6-tris(2-pyridyl)-s-triazine (TPTZ)] are reported. Single-crystal X-ray diffraction analysis of these materials enabled the exploration of the structural relationship between the benzoic acids and the chelating N-donor as well as providing a platform to evaluate the effects of ligand choice on uranyl hydrolysis and subsequent oligomerization. At an unadjusted pH (ca. 3), a mix of uranyl monomers and dimers are observed, dimer formation resulting from both bridging carboxylate linkers and hydroxo bridges. Assembly by halogen- and hydrogen-bonding interactions as well as π-π interactions was observed depending on the experimental conditions utilized. Further, spectroscopic characterization (both vibrational and luminescence) of complexes 1, 4, and 5 to explore the effects of the electron-donating ability of the capping ligand on the corresponding uranyl luminescence and vibrational spectra suggests that there is a relationship between the observed bathochromic shifts and the electron-donating ability of the capping ligands. (Copyright copyright 2015 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim)

Investigation of uranyl-ion hydrolysis in uranyl pertechnetate and uranyl perchlorates solutions by two-phases potentiometric titration method

International Nuclear Information System (INIS)

Volk, V.I.; Belikov, A.D.

1977-01-01

The applicability of the method of two-phase potentiometric titration for studying hydrolysis of multi-charge ions has been shown. Hydrolysis of uranyl-ion has been investigated and hydrolysis constants in the solutions of uranyl pertechnetate and perchlorate have been calculated equal to (6.2+-0.15)x10 -5 and (9.25+-0.5)10 -5 , respectively. Infrared spectra of the initial crystallohydrates of uranyl pertechnetate and perchlorate has been analyzed. The data on hydrolysis of an uranyl-ion and IR spectra of crystallohydrates of the investigated salts have revealed the ability of pertechnetate ion to complexing with an uranyl group

Engineering of specific uranyl-coordination sites in the calcium-binding motif of Calmodulin

International Nuclear Information System (INIS)

Beccia, M.; Pardoux, R.; Sauge-Merle, S.; Bremond, N.; Lemaire, D.; Berthomieu, C.; Delangle, P.; Guilbaud, P.

2014-01-01

Complete text of publication follows: Characterization of heavy metals interactions with proteins is fundamental for understanding the molecular factors and mechanisms governing ions toxicity and speciation in cells. This line of research will also help in developing new molecules able to selectively and efficiently bind toxic metal ions, which could find application for bio-detection or bioremediation purposes. We have used the regulatory calcium-binding protein Calmodulin (CaM) from A. thaliana as a structural model and, starting from it, we have designed various mutants by site-directed mutagenesis. We have analysed thermodynamics of uranyl ion binding to both sites I and II of CaM N-terminal domain and we have identified structural factors governing this interaction. Selectivity for uranyl ion has been tested by studying reactions of the investigated peptides with Ca 2+ , in the same conditions used for UO 2 2+ . Spectro-fluorimetric titrations and FTIR analysis have shown that the affinity for uranyl increases by phosphorylation of a threonine in site I, especially approaching the physiological pH, where the phospho-threonine side chain is deprotonated. Based on structural models obtained by Molecular Dynamics, we tested the effect of a two residues deletion on site I properties. We obtained an almost two orders of magnitude increase in affinity for uranyl, with a sub-nanomolar dissociation constant for the uranyl complex with the non phosphorylated peptide, and an improved uranyl/calcium selectivity. Allosteric effects depending on Ca 2+ and UO 2 2+ binding have been investigated by comparing thermodynamic parameters obtained for mutants having both sites I and II able to chelate metal ions with those of mutants consisting of just one active site

Engaging the Terminal: Promoting Halogen Bonding Interactions with Uranyl Oxo Atoms.

Science.gov (United States)

Carter, Korey P; Kalaj, Mark; Surbella, Robert G; Ducati, Lucas C; Autschbach, Jochen; Cahill, Christopher L

2017-11-02

Engaging the nominally terminal oxo atoms of the linear uranyl (UO 2 2+ ) cation in non-covalent interactions represents both a significant challenge and opportunity within the field of actinide hybrid materials. An approach has been developed for promoting oxo atom participation in a range of non-covalent interactions, through judicious choice of electron donating equatorial ligands and appropriately polarizable halogen-donor atoms. As such, a family of uranyl hybrid materials was generated based on a combination of 2,5-dihalobenzoic acid and aromatic, chelating N-donor ligands. Delineation of criteria for oxo participation in halogen bonding interactions has been achieved by preparing materials containing 2,5-dichloro- (25diClBA) and 2,5-dibromobenzoic acid (25diBrBA) coupled with 2,2'-bipyridine (bipy) (1 and 2), 1,10-phenanthroline (phen) (3-5), 2,2':6',2''-terpyridine (terpy) (6-8), or 4'-chloro-2,2':6',2''-terpyridine (Cl-terpy) (9-10), which have been characterized through single crystal X-ray diffraction, Raman, Infrared (IR), and luminescence spectroscopy, as well as through density functional calculations of electrostatic potentials. Looking comprehensively, these results are compared with recently published analogues featuring 2,5-diiodobenzoic acid which indicate that although inclusion of a capping ligand in the uranyl first coordination sphere is important, it is the polarizability of the selected halogen atom that ultimately drives halogen bonding interactions with the uranyl oxo atoms. © 2017 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

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

International Nuclear Information System (INIS)

Massicano, Adriana V.F.; Akanji, Akinkunmi G.; Santos, Josefina S.; Pujatti, Priscilla B.; Couto, Renata M.; Massicano, Felipe; Araujo, Elaine Bortoleti de

2009-01-01

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 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 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 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)

Thermodynamic properties of actinide complexes. IV. Thorium(IV)- and uranyl(VI)-malonate systems

Energy Technology Data Exchange (ETDEWEB)

Di Bernardo, P; Di Napoli, V; Cassol, A; Magon, L [Consiglio Nazionale delle Ricerche, Padua (Italy). Lab. di Chimica e Tecnologia dei Radioelementi

1977-01-01

The stability constants and the enthalpies of formation of thorium(IV)- and uranyl(VI)-malonate complexes have been determined by potentiometric and calorimetric titrations in 1.00 M solutions of Na(ClO/sub 4/) at 25/sup 0/C. All complexes formed are found to be stabilized by a large entropy gain. The values for the stability constants agree with an ionic bonding model. The malonate behaves as a bidentate ligand forming only chelate complexes.

Barium uranyl diphosphonates

Energy Technology Data Exchange (ETDEWEB)

Nelson, Anna-Gay D., E-mail: nelsoa@umich.edu [Department of Civil Engineering and Geological Sciences and Department of Chemistry and Biochemistry, University of Notre Dame, Notre Dame, IN 46556 (United States); Department of Earth and Environmental Sciences, University of Michigan, Ann Arbor, MI 48109-1005 (United States); Alekseev, Evgeny V. [Institute of Energy and Climate Research (IEK-6), Forschungszentrum Juelich Wilhelm-Johnen-Strasse, Juelich 52428 (Germany); Ewing, Rodney C. [Department of Earth and Environmental Sciences, University of Michigan, Ann Arbor, MI 48109-1005 (United States); Albrecht-Schmitt, Thomas E. [Department of Civil Engineering and Geological Sciences and Department of Chemistry and Biochemistry, University of Notre Dame, Notre Dame, IN 46556 (United States)

2012-08-15

Three Ba{sup 2+}/UO{sub 2}{sup 2+} methylenediphosphonates have been prepared from mild hydrothermal treatment of uranium trioxide, methylendiphosphonic acid (C1P2) with barium hydroxide octahydrate, barium iodate monohydrate, and small aliquots of HF at 200 Degree-Sign C. These compounds, Ba[UO{sub 2}[CH{sub 2}(PO{sub 3}){sub 2}]{center_dot}1.4H{sub 2}O (Ba-1), Ba{sub 3}[(UO{sub 2}){sub 4}(CH{sub 2}(PO{sub 3}){sub 2}){sub 2}F{sub 6}]{center_dot}6H{sub 2}O (Ba-2), and Ba{sub 2}[(UO{sub 2}){sub 2}(CH{sub 2}(PO{sub 3}){sub 2})F{sub 4}]{center_dot}5.75H{sub 2}O (Ba-3) all adopt layered structures based upon linear uranyl groups and disphosphonate molecules. Ba-2 and Ba-3 are similar in that they both have UO{sub 5}F{sub 2} pentagonal bipyramids that are bridged and chelated by the diphosphonate moiety into a two-dimensional zigzag anionic sheet (Ba-2) and a one-dimensional ribbon anionic chain (Ba-3). Ba-1, has a single crystallographically unique uranium metal center where the C1P2 ligand solely bridges to form [UO{sub 2}[CH{sub 2}(PO{sub 3}){sub 2}]{sup 2-} sheets. The interlayer space of the structures is occupied by Ba{sup 2+}, which, along with the fluoride ion, mediates the structure formed and maintains overall charge balance. - Graphical abstract: Illustration of the stacking of the layers in Ba{sub 3}[(UO{sub 2}){sub 4}(CH{sub 2}(PO{sub 3}){sub 2}){sub 2})F{sub 6}]{center_dot}6H{sub 2}O viewed along the c-axis. The structure is constructed from UO{sub 7} pentagonal bipyramidal units, U(1)O{sub 7}=gray, U(2)O{sub 7}=yellow, barium=blue, phosphorus=magenta, fluorine=green, oxygen=red, carbon=black, and hydrogen=light peach. Highlights: Black-Right-Pointing-Pointer The polymerization of the UO{sub 2}{sup 2+} sites to form uranyl dimers leads to structural variations in compounds. Black-Right-Pointing-Pointer Barium cations stitch uranyl diphosphonate anionic layers together, and help mediate structure formation. Black-Right-Pointing-Pointer HF acts as both a

Monoclonal antibody hapten radiopharmaceutical delivery

International Nuclear Information System (INIS)

Goodwin, D.A.; McTigue, M.

1986-01-01

One hundred μg of monoclonal antibody (MoAb) CHA255 with a binding constant Kb of 4 x 10 9 was complexed with indium-111 labelled BLEDTA II, BLEDTA IV, benzyl EDTA, and an EDTA conjugate of Fab. The 24-h tumour and organ distribution of BALB/c mice bearing KHJJ tumours was studied for each compound alone, the antibody complex, and 3 h following a chelate chase of the antibody complex. Whole body biological half-life was measured for 7 days with and without a chelate chase for each antibody complex. The 24-h whole body counts dropped 20 to 60% and blood concentration fell over 89% within 3 h of administering the chelate chase. Theoretical equivalent human organ doses were calculated from the 24-h organ concentrations, effective half-life, and MIRD 11 S values (absorbed dose per cumulated activity). Liver and spleen were the target organs, with the dose ranging from 0.50 to 3.91 rads mCi -1 . The reduction in organ radiation dose varied up to 95% following the chelate chase. Rapid selective renal clearance of chelate labelled radiopharmaceuticals by competitive inhibition (chelate chase) of their reversible binding to monoclonal antibodies enhances tumour imaging and improves the radiation dosimetry. (author)

Ratiometric colorimetric determination of coenzyme A using gold nanoparticles and a binuclear uranyl complex as optical probes

International Nuclear Information System (INIS)

Wu, Rurong; Liao, Lifu; Li, Shijun; Yang, Yanyan; Xiao, Xilin; Nie, Changming

2016-01-01

We describe a ratiometric colorimetric method for the determination of coenzyme A (CoA) by using gold nanoparticles (AuNPs) and bis-uranyl-bis-sulfosalophen (BUBSS) as optical probes. BUBSS is a binuclear uranyl complex and formed through the chelating reaction of two uranyl ions with bis-sulfosalophen. CoA is captured by the AuNPs via the thiol group and this leads to the formation of CoA-AuNPs. In a second step, BUBSS binds two CoA-AuNPs through a coordination reaction between the uranyl ions in BUBSS and the phosphate groups in CoA-AuNPs. This causes the CoA-AuNPs to aggregate and results in a color change from wine red to blue. A ratiometric colorimetric assay was established for CoA based on the ratiometric measurement of absorbance changes at 650 and 525 nm. Their ratio is linearly related to the concentration of CoA in the 0 to 1.2 μmol⋅L -1 range, with a 6 nmol⋅ L- 1 detection limit under optimal conditions. The method was successfully applied to the determination of CoA in spiked liver samples with recoveries between 99.4 and 102.6 %. (author)

Labeling of monoclonal antibodies with a 67Ga-phenolic aminocarboxylic acid chelate. Part I. Chemistry and labeling technique.

Science.gov (United States)

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

1986-01-01

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 tightly complexes 67Ga, was synthesized. The 67Ga-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 67Ga. In vitro stability was evaluated in human serum at 37 degrees C and showed a half-life of about 120 h for the release of 67Ga from the labeled Ab during the initial phase of incubation. This in vitro halflife is similar to that measured for 111In-DTPA labeled Abs. Because of the high stability of the 67Ga-P-EDDHA chelate, the in vivo formation of radioactive labeled transferrin by transchelation, as described for 111In-DTPA labeled Abs, should, however, be reduced by this labeling technique.

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.

Complex formation reactions of uranyl(VI) with neutral N-donors in dimethyl sulfoxide. Influence of small amounts of water

International Nuclear Information System (INIS)

Cassol, A.; Di Bernardo, P.; Zanonato, P.; Portanova, R.; Tolazzi, M.

1990-01-01

Quantitative information about the existence and thermodynamic stability of uranyl(VI) ion complexes based solely upon nitrogen coordination has been obtained in the solvent dimethyl sulfoxide. Calorimetric, potentiometric, and FT-IR investigations, under controlled anhydrous conditions, show that the uranyl(VI) ion can form both mono and bis chelates with the ethylenediamine ligand and only a mono chelate of rather low stability with propylenediamine. With the monodentate ligand n-butylamine only a very weak metal-ligand interaction has been detected. The stability constants and the enthalpy and entropy changes have been calculated for the identified coordinated species. All data refer to 25.0 degree C and a tetraethylammonium perchlorate medium of ionic strength 0.1 M. All the complexes are enthalpy stabilized whereas the entropy contributions oppose the complex formation. Calorimetric and FT-IR measurements carried out to investigate the effects of small amounts of water present show that a very low water concentration, comparable to that of the coordinating metal ion, can give rise to hydrolysis reactions that may compete with complex formation. This is due to the combined action of different factors that are discussed. 39 refs., 6 figs., 1 tab

Novel two-dimensional uranyl-organic assemblages in the citrate and D(-)-citramalate families

International Nuclear Information System (INIS)

Thuery, P.

2008-01-01

Uranyl nitrate reacts with D(-)-citramalic acid (H(3)citml) under mild hydrothermal conditions to give the two-dimensional polymer [UO 2 (Hcitml)] 1, in which each ligand chelates one metal atom through its hydroxyl and alpha- carboxylate groups and binds to three others in monodentate fashion. The resulting neutral layers display isolated uranyl pentagonal bipyramidal polyhedra. Whereas citric acid (H(4)cit) has been shown previously to give various three- and mono-dimensional uranyl organic assemblages, complexation under hydrothermal conditions in the presence of either NaOH/NEt 4 Cl or pyridine yields the complexes [NEt 4 ] 2 [(UO 2 ) 3 (cit) 2 (H 2 O) 2 ]· 2H 2 O 2 and [Hpy] 2 )[(UO 2 ) 3 (cit)(Hcit)(OH)] 3, respectively, which both crystallize as two- dimensional frameworks. The layers are either planar and separated by the counter ions in 2 or corrugated and hydrogen bonded to one another in 3. In both 2 and 3, [UO 2 (cit)] 2 4- dimeric subunits with edge-sharing pentagonal bipyramidal uranium coordination polyhedra are present but, in both cases and in contrast with previous structures containing [UO 2 (Hcit)] 2 2- dimers, the carboxylate group not involved in the dimer formation is coordinated to another uranyl unit, which is part of either a centrosymmetric hexagonal bipyramidal bis-aquated group or a different, [(UO 2 ) 2 (Hcit)(OH)] dimer. These examples of two- dimensional assemblages further illustrate the variety of architectures which can be obtained with citric and related acids and the important structure-directing effects of the counter ions. (author)

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

Preparation of Ga-67 labeled monoclonal antibodies using deferoxamine as a bifunctional chelating agent

International Nuclear Information System (INIS)

Endo, K.; Furukawa, T.; Ohmomo, Y.

1984-01-01

Ga-67 labeled monoclonal IgG or F(ab')/sub 2/ fragments against α-fetoprotein and β-subunit of human choriogonadotropin (HCG), were prepared using Deferoxamine (DFO) as a bifunctional chelating agent. DFO, a well-known iron chelating agent, was conjugated with monoclonal antibodies (Ab) by a glutaraldehyde two step method and the effect of conjugation on the Ab activities was examined by RIA and Scatchard plot analysis. In both monoclonal Ab preparations, the conjugation reaction was favored as the pH increased. However, Ab-binding activities decreased as the molecular ratios of DFO to Ab increased. Preserved Ab activities were observed when Ab contained DFO per Ab molecule less than 2.1. At a ratio of over 3.3 DFO molecules per Ab, the maximal binding capacity rather than the affinity constant decreased. The inter-molecular cross linkage seemed to be responsible for the deactivation of binding activities. The obtained DFO-Ab conjugates, were then easily labeled with high efficiency and reproducibility and Ga-67 DFO-Ab complexes were highly stable both in vitro and in vivo. Thus, biodistribution of Ga-67 labeled F(ab')/sub 2/ fragments of monoclonal Ab to HCG β-subunit was attempted in nude mice transplanted with HCG-producing human teratocarcinoma. Tumor could be visualized, in spite of relatively high background imaging of liver, kidney and spleen. The use of DFO as a bifunctional chelating agent provided good evidence for its applicability to labeling monoclonal Ab with almost full retention of Ab activities. Further, availability of Ga-68 will make Ga-68 DFO-monoclonal Ab a very useful tool for positron tomography imaging of various tumors

Nuclear medicine: Monoclonal antibodies

International Nuclear Information System (INIS)

Endo, K.; Sakahara, H.; Koizumi, M.; Kawamura, Y.; Torizuka, K.; Yokoyama, A.

1986-01-01

Antitumor monoclonal antibody was successfully labeled with Tc-99m by using dithiosemicarbazone (DTS) as a bifunctional chelating agent. In the first step, DTS was coupled to antibody without loss of immunoreactivity; the compound then efficiently formed a neutral 1:1 chelate with pentavalent or tetravalent Tc-99m. Imaging with Tc-99m-labeled monoclonal antibody to human osteosarcoma (OST-7) clearly displayed a small tumor in nude mice at 6 and 24 hours after intravenous administration. The tumor-to-blood ratio of the Tc-99m-labeled monoclonal antibody was higher than that of a radioiodinated antibody and similar to that of an In-111-labeled antibody. Thus, conjugation of DTS to monoclonal antibody followed by radiometalation is a simple and efficient method of preparing Tc-99m-labeled monoclonal antibody

Role of chelates in magnetic resonance imaging studies

Directory of Open Access Journals (Sweden)

Tripathi Laxmi

2009-01-01

Full Text Available Imaging studies are tests performed with a variety of techniques that produce pictures of the inside of a patient′s body. Magnetic resonance imaging (MRI is an imaging technique based on the principles of nuclear magnetic resonance. MRI uses a powerful magnetic field, radio waves, and a computer to produce detailed pictures of organs, soft tissues, bone, and virtually all other internal body structures. Chelates have a wide application in such imaging techniques. Chelates in imaging studies are used alone as radioactive agents or conjugated to monoclonal antibodies or to DNA as radioactive agents. Technetium chelates and gadolinium chelates are being widely used as magnetic resonance contrast media.

DOTA-Functionalized Polylysine: A High Number of DOTA Chelates Positively Influences the Biodistribution of Enzymatic Conjugated Anti-Tumor Antibody chCE7agl.

OpenAIRE

Grünberg Jürgen; Jeger Simone; Sarko Dikran; Dennler Patrick; Zimmermann Kurt; Mier Walter; Schibli Roger

2013-01-01

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 (DOTA)1-decalysine, (DOTA)3-decaly...

Adsorption equilibrium of uranium from seawater on chelating resin containing amide oxime group

International Nuclear Information System (INIS)

Hori, Takahiro; Saito, Kyoichi; Furusaki, Shintaro; Sugo, Takanobu; Okamoto, Jiro.

1987-01-01

Chelating resins containing amide oxime group were synthesized by radiation-induced graft polymerization. The amount of the amide oxime groups was controlled below about 0.1 mol per kg of base polymer. The adsorption equilibrium of uranium from seawater on this resin was investigated. It was suggested that two neighboring amide oxime groups on the grafted chain captured one uranyl ion, and that single amide oxime ligand had little capacity for the adsorption of uranium. The adsorption equilibrium was correlated by a Langmuir-type equation. The content of neighboring amide oxime groups was 0.406 x 10 -3 mol per kg of base polymer, which corresponded to 0.39 % of the total amount of amide oxime groups. The apparent stoichiometric stability constant for the complex of uranyl ion with the neighboring amide oxime groups in seawater was calculated to be 10 -21.7 . (author)

Stereognostic coordination chemistry. 1. The design and synthesis of chelators for the uranyl ion

International Nuclear Information System (INIS)

Franczyk, T.S.; Czerwinski, K.R.; Raymond, K.N.

1992-01-01

A new approach to the molecular recognition of metal oxo cations is introduced based on a ligand design strategy that provides at least one hydrogen bond donor for interaction with oxo group(s) as well as conventional electron pair donor ligands for coordination to the metal center. This concept of stereognostic coordination of oxo metal ions is exemplified in the design of four tripodal ligands-tris[2-(2-carboxyphenoxy)ethyl]amine[NEB],tris[3-(2-carboxyphenoxy)propyl]amine[NPB], tris[3-(2-carboxynaphthyl-3-oxy)propyl]amine [NPN], and tris[3-(2-carboxy=4octadecylphenoxy)propyl]amine[NPodB] - for sequestration of the uranyl ion. The ligands NEB, NPB, and NPN form 1:1 complexes with UO 2 2+ . The bidentate coordination of carboxyl groups of these compounds is indicated by the infrared spectra, which offer some support for the presence of a hydrogen bond to the uranyl group. Mass spectral data corroborate CPK model predictions that more than five intervening atoms between the tertiary nitrogen atom and the carboxylate groups are required for metal ion incorporation and monomeric complex formation. Solvent extractions of aqueous UO 2 2+ into chloroform solutions of the ligands have shown them to be powerful extractants. In the case of the very hydrophobic ligand NPodB the stoichiometry of the complexation reaction is shown to be 1:1 UO 2 /ligand complex formed by the release of 3 protons. The extraction is quantitative at pH 2.5, and an effective extraction coefficient of about 10 11 is estimated for neutral aqueous solutions of UO 2 2+ . 81 refs., 13 figs., 2 tabs

Preparation and crystal structure of a nickel (II)-uranyl (VI) binuclear chelate

Energy Technology Data Exchange (ETDEWEB)

Graziani, R; Vidali, H [Padua Univ. (Italy). Istituto di Chimica Generale; Casellato, U; Vigato, P A [Consiglio Nazionale delle Ricerche, Padua (Italy). Lab. di Chimica e Tecnologia dei Radioelementi

1978-04-01

The structure of the heterobinuclear complex of Ni/sup 2/ and (UO/sub 2/)/sup 2/ with the tetraanionic ligand derived from the condensation of 1,2-diaminoethane with o-acetoacetylphenol has been determined from diffractometer data and refined to R = 7.2%. The crystals are monoclinic, P2/sub 1//a, with a = 20.65(2), b = 8.58(1), c = 14.68(2) Angstroem and ..beta.. = 97.78(5)/sup 0/; Z = 4. The ligand employed has two different coordination sets of atoms, N/sub 2/O/sub 2/ and O/sub 2/O/sub 2/, two oxygen atoms being common to both donor sets. In the complex the nickel ion, which is four coordinate but not square planar, is retained in the inner N/sub 2/O/sub 2/ chamber, whilst the uranyl ion is incorporated in the outer O/sub 2/O/sub 2/ chamber. A molecule of solvent is retained to preserve the preffered seven coordination of uranium.

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

International Nuclear Information System (INIS)

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

2001-01-01

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 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') 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 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 125 I-labeled native 12H12 at 24h and 48h postinjection. No difference in the tumor uptake of both the 68 Ga and 67 Ga labeled chelate was observed. PET imaging of mice, started 1h postinjection of the 68 Ga chelate, clearly visualized all tumors

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.

Uranyl complexes as scaffolding or spacers for cucurbit[6]uril molecules in homo- and heterometallic species, including a uranyl-lanthanide complex

Energy Technology Data Exchange (ETDEWEB)

Thuery, Pierre [NIMBE, CEA, CNRS, Universite Paris-Saclay, CEA Saclay, Gif-sur-Yvette (France)

2017-06-16

The reaction of uranyl nitrate with cucurbit[6]uril (CB6) and carboxylic or sulfonic ligands under hydrothermal conditions and in the presence of additional metal cations (K{sup I} or Ce{sup III}) or cosolvents provided four complexes, which were crystallographically characterized. The compound [(UO{sub 2}){sub 2}K{sub 2}(CB6)(adc){sub 2}(NO{sub 3}){sub 2}(H{sub 2}O){sub 2}].5H{sub 2}O (1), where H{sub 2}adc is 1,3-adamantanedicarboxylic acid, crystallizes in the form of a central K{sub 2}(CB6){sup 2+} column surrounded by two one-dimensional (1D) polymeric UO{sub 2}(adc)(NO{sub 3}){sup -} chains attached to the column by nitrate bridges, with a perfect match of the repeat lengths in the two subunits. The longer 1,3-adamantanediacetic acid (H{sub 2}adac) gives the complex [(UO{sub 2}){sub 2}(adac){sub 2}(HCOOH){sub 2}].CB6.6H{sub 2}O (2), in which the 1D uranyl-containing polymer and columns of CB6 molecules form a layered arrangement held by weak CH..O hydrogen bonds. The complex formed with the dipotassium salt of methanedisulfonic acid (K{sub 2}mds), [(UO{sub 2}){sub 2}K{sub 2}(CB6)(mds){sub 2}(OH){sub 2}(H{sub 2}O){sub 8}].4H{sub 2}O (3), is a 1D polymer, in which K{sub 2}(CB6){sup 2+} units are connected to one another by doubly hydroxide-bridged uranyl dimers in which the disulfonates are terminal, chelating ligands; connection between the two subunits is solely through potassium oxo-bonding to uranyl. The complex [(UO{sub 2}){sub 2}Ce{sub 2}(CB6)(C{sub 2}O{sub 4}){sub 3}(NO{sub 3}){sub 4}(H{sub 2}O){sub 6}].2H{sub 2}O (4) is a 1D polymer containing bridging oxalate ligands formed in situ, in which CB6 is coordinated to the lanthanide cations only; one nitrate ligand and one water ligand, hydrogen-bonded to each other, are included in the CB6 cavity, with the possible occurrence of interactions between nitrate oxygen atoms and ureido carbon atoms. (copyright 2017 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim)

Production of chelating agents by Pseudomonas aeruginosa grown in the presence of thorium and uranium

International Nuclear Information System (INIS)

Premuzic, E.T.; Lin, M.; Francis, A.J.; Schubert, J.

1986-01-01

Chelating agents produced by microorganisms enhance the dissolution of iron increasing the mobility and bioavailability of the metal. Since some similarities exist in the biological behavior of ferric, thorium and uranyl ions, microorganisms resistant to these metals and which grow in their presence may produce sequestering agents of Th and U, and other metals in a manner similar to the complexation of iron by siderophores. The ability of P. aeruginosa to elaborate sequestering agents in medium containing thorium or uranium salts was tested. Uranium has a stronger inhibitory effect on growth of the organism than thorium at similar concentrations. Analyses of the culture media have shown, that relative to the control, and under the experimental conditions used, the microorganisms have produced several new chelating agents for thorium and uranium. Extracts containing these chelating agents have been tested for their decorporation potential. In vitro mouse liver bioassay and in vivo mouse toxicity tests indicate that their efficiency is comparable to DTPA and DFOA and that they are virtually non-toxic to mice. The bacterially produced compounds resemble, but are not identical to the known iron chelating siderophores isolated from microorganisms. Some of their chemical properties are also discussed. (author)

Design and synthesis of new poly-phosphorylated upper-rim modified calix[4]arenes as potential and selective chelating agents of uranyl ion

International Nuclear Information System (INIS)

Migianu-Griffoni, E.; Mbemba, C.; Burgada, R.; Lecouvey, M.; Lecercle, D.; Taran, F.

2009-01-01

New upper-rim poly-phosphorylated calix[4]arenes were designed for decorporation of uranium in case of nuclear contamination. A ligand system containing four pre-organized 1-hydroxymethylene-1, 1-bisphosphonic acid moieties anchored onto a calix[4]arene platform has been developed. Three calix[4]-arene-bis-phosphonates were efficiently prepared in multi-step syntheses with a variable carbon chain length between the bis-phosphonate and the calix[4]arene. Affinity constants towards uranyl ion were determined and compared with those of bis(HEDP) and tris(HEDP) phosphonates, known as efficient ligands for uranyl. (authors)

Evaluation of renal function following administration of ethane-1-hydroxy-1,1-biphosphonate (EHBP) in animals submitted to oral intoxication with uranyl nitrate

International Nuclear Information System (INIS)

Martinez, A.B.; Mandalunis, P.M.; Bozal, C.B.; Cabrini, Romulo L.; Ubios, A.M.

2003-01-01

Workers involved in the processes of extraction, purification and manufacture of uranium of nuclear plants are occupationally exposed to both natural and enriched uranium. Several chelating agents (TIRON, EDTA, BAI, etc.) have been tested in terms of their capacity to sequester uranium before it reaches its target organs. Our laboratory has studied a first generation biphosphonate, ethane-1-hydroxy-1,1-biphosphonate (EHBP). We have shown that treatment with EHBP induces survival rates of 75% and 100% in adult and suckling rats respectively intoxicated with an intraperitoneal injection of uranyl nitrate. There are no data available to date on the renal function following treatment with EBHP to counteract the toxic effects of an oral lethal dose of uranyl nitrate. The aim of the present study was to assay creatininemia and uremia as end-points to assess renal function. The results obtained reveal that the alterations in renal function induced by oral uranyl nitrate intoxication can be reduced at 48 hours and reverted at 14 days by subcutaneous or oral administration of EHBP. (author)

Preparation and crystal structure of a copper(2) uranyl(6) binuclear chelate

Energy Technology Data Exchange (ETDEWEB)

Graziani, R; Vidali, M [Padua Univ. (Italy). Istituto di Chimica Generale; Casellato, U; Vigato, P A [Consiglio Nazionale delle Ricerche, Padua (Italy). Lab. di Chimica e Tecnologia dei Radioelementi

1978-08-01

The structure of the heterobinuclear complex of Cu/sup 2 +/ and (UO/sub 2/)/sup 2 +/ with the tetraanionic ligand derived from the condensation of 1,2-diamiaminoethane with o-acetoacetylphenol has been determined from diffractometer data and refined to R = 5.2%. The crystals are monoclinic, P2/sub 1//..cap alpha.., with ..cap alpha.. = 26.22(2), b = 14.79(2), c = 8.10(1) A and ..beta.. = 104.65(5)/sup 0/; Z = 4. The ligand employed has two different coordination sets of atoms, N/sub 2/O/sub 2/ and O/sub 2/O/sub 2/, two oxygen atoms being common to both donor sets. In the complex the copper atom, which is retained in the inner N/sub 2/O/sub 2/ chamber, is five coordinate being axially bonded to a solvent molecule, whilst the uranyl ion is incorporated in the outer O/sub 2/O/sub 2/ chamber. Another molecule of solvent is retained to preserve the preferred seven coordination of uranium.

Uranyl fluoride luminescence in acidic aqueous solutions

International Nuclear Information System (INIS)

Beitz, J.V.; Williams, C.W.

1996-01-01

Luminescence emission spectra and decay rates are reported for uranyl species in acidic aqueous solutions containing HF or added NaF. The longest luminescence lifetime, 0.269 ± 0.006 ms, was observed from uranyl in 1 M HF + 1 M HClO 4 at 296 K and decreased with increasing temperature. Based on a luminescence dynamics model that assumes equilibrium among electronically excited uranyl fluoride species and free fluoride ion, this long lived uranyl luminescence in aqueous solution is attributed primarily to UO 2 F 2 . Studies on the effect of added LiNO 3 or Na 2 WO 4 ·2H 2 O showed relatively weak quenching of uranyl fluoride luminescence which suggests that high sensitivity determination of the UF 6 content of WF 6 gas should be feasible via uranyl luminescence analysis of hydrolyzed gas samples of impure WF 6

Uranyl tris-beta-diketonate complexes

International Nuclear Information System (INIS)

Sidorenko, G.V.; Adamov, V.M.; Shcherbakova, L.L.; Suglubov, D.N.

1986-01-01

Uranyl tris-pivaloyltrifluoroacetonates (M/IOTA/UO 2 L 3 ; M/IOTA/ = Na, K, Cs, 1/2Ba, NR 4 ; R = C 8 H 17 ) and tris-dipivaloylmethanate (M/IOTA/UO 2 L/IOTA/ 3 , M/IOTA/ = K) have been synthesized for the first time. The compounds were characterized by chemical analysis and IR, NMR, and mass spectra. NaUO 2 L 3 , KUO 2 L 3 , CsUO 2 L 3 and Ba(UO 2 ) 2 L 6 sublime in high vacuum with partial decomposition. Specifically, decomposition gives UL 4 , identified by mass spectrometry. All the tris-complexes except those with outer-sphere NR 4 cation are characterized by an asymmetric structure of the uranyl group, recorded by IR spectroscopy using isotopic substitution of 18 O in uranyl. NMR spectra of the tris-complexes indicate the equivalence of all beta-diketonate groups, i.e., a coordination number of six for uranyl

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.

Luminescence enhancement of uranyl ion by benzoic acid in acetonitrile

International Nuclear Information System (INIS)

Satendra Kumar; Maji, S.; Joseph, M.; Sankaran, K.

2014-01-01

Uranyl ion is known for its characteristic green luminescence and therefore luminescence spectroscopy is a suitable technique for characterizing different uranyl species. In aqueous medium, luminescence of uranyl ion is generally weak due to its quenching by water molecules and therefore in order to enhance the luminescence of uranyl ion in aqueous medium, luminescence enhancing reagents such as H 3 PO 4 , H 2 SO 4 , HCIO 4 have been widely used. The other method to enhance the uranyl luminescence is by ligand sensitized luminescence, a method well established for lanthanides. In this work, luminescence of uranyl ion is found to be enhanced by benzoic acid in acetonitrile medium. In aqueous medium benzoic acid does not enhance the uranyl luminescence although it forms 1:1 and 1:2 complexes with uranyl ion. Luminescence spectra of uranyl benzoate revealed that enhancement is due to sensitization of uranyl luminescence by benzoate ions. UV-Vis spectroscopy has been utilized to characterize the specie formed in the in acetonitrile medium. UV-Vis spectroscopy along with luminescence spectra revealed that the specie to be tribenzoate complex of uranyl (UO 2 (C 6 H 5 COO) 3 ) - having D 3 h symmetry. (author)

Sorption of uranyl ions on hydrous oxides

International Nuclear Information System (INIS)

Gupta, A.R.; Venkataramani, B.

1988-01-01

Sorption of uranyl ions on hydrous titanium oxide (HTiO), magnetite (MAG), and hydrous thorium oxide (HThO) has been studied as a function of pH. Hydrous oxides have been characterized by their pH-titration curves, intrinsic dissociation constants (pK ai * ) and point of zero charge (pH pzc ). The fraction of protonated surface hydroxyl groups as well as the surface pH (pH surf ) as a function of solution pH have been computed. The distribution of various hydrolyzed species of uranyl ions with solution pH have been compared with uranyl sorption isotherm on these oxides. Sorption edge in all the cases occurs when free hydroxyl groups are available on the surface and pH surf is sufficiently high to favor the formation of dimer-like species on the surface. A new model for the sorption process, called surface hydrolysis model, which explains these and other features of uranyl sorption on hydrous oxides has been proposed. The model visualizes the sorption process as linking of uranyl ions with two adjacent free surface hydroxyl groups without deprotonation (provided the surface pH is high for the hydrolysis of uranyl ions) and formation of dimer-like structures on the surface. The new model has been successfully applied to the present and other available data on uranyl ion sorption on hydrous oxides. (author)

Quantification of uranyl in presence of citric acid

International Nuclear Information System (INIS)

Garcia G, N.; Barrera D, C.E.; Ordonez R, E.

2007-01-01

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)

Metal complex derivatives of hydrogen uranyl phosphate

International Nuclear Information System (INIS)

Grohol, D.; Blinn, E.L.

1994-01-01

Derivatives of hydrogen uranyl phosphate were prepared by incorporating transition metal complexes into the uranyl phosphate matrix. The transition metal complexes employed include bis(ethylenediamine)copper(II), bis(1,3-propanediamine)copper(II) chloride, (triethylenetetramine)copper(II), (1,4,8,11-tetraazacyclotetradecane)copper(II), (1,4,8,12-tetraazacyclopentadecane)copper(II), (1,4,8,11-tetraazacyclotetradecane)nickel(II) chloride, (triethylenetetramine)nickel(II) and others. The chemical analyses of these derivatives indicated that the incorporation of the transition metal complexes into the uranyl phosphate matrix via ion exchange was not stoichiometric. The extent of ion exchange is dependent on the size and structure of the transition metal complex. All complexes were characterized by X-ray powder diffractometry, electronic and infrared spectra, thermal analyses and chemical analysis. An attempt was made to correlate the degree of quenching of the luminescence of the uranyl ion to the spacing between the uranyl phosphate layers in the derivatives

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

Science.gov (United States)

Grünberg, Jürgen; Jeger, Simone; Sarko, Dikran; Dennler, Patrick; Zimmermann, Kurt; Mier, Walter; Schibli, Roger

2013-01-01

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 (DOTA)1-decalysine, (DOTA)3-decalysine or (DOTA)5-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 (177)Lu 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-[(DOTA)3-decalysine]2 and 49.9±3.1% ID/g at 48 h for chCE7agl-[(DOTA)5-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 (DOTA)3 versus 11.7±1.4% ID/g (DOTA)5, pDOTA)3 versus 5.8±0.7 (DOTA)5, pDOTA-substituted decalysine ((DOTA)5-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 radioimmunotherapy and potentially antibody-drug conjugates (ADCs).

Complexation of uranyl ion with sulfonates. One- to three-dimensional assemblies with 1,5- and 2,7-naphthalenedisulfonates

Energy Technology Data Exchange (ETDEWEB)

Thuery, Pierre [NIMBE, CEA, CNRS, Universite Paris-Saclay, CEA Saclay, Gif-sur-Yvette (France); Harrowfield, Jack [ISIS, Universite de Strasbourg (France)

2017-02-03

Uranyl nitrate was treated with the sodium salt of either 1,5- or 2,7-naphthalenedisulfonate (1,5-ndsNa{sub 2} or 2,7-ndsNa{sub 2}, respectively) under (solvo)-hydrothermal conditions, in the presence of additional coligands and/or metal cations, to give six new complexes, which were characterized by determination of their crystal structures. Complex [UO{sub 2}(1,5-nds)(H{sub 2}O)] (1) crystallizes as a three-dimensional (3D) framework, with both sulfonate groups coordinated in the O,O{sup '}-bridging mode. In the presence of the N-chelating species 2,2{sup '}-bipyridine (bipy) or 1,10-phenanthroline (phen), the three complexes [(UO{sub 2}){sub 2}(1,5-nds)(OH){sub 2}(bipy){sub 2}].H{sub 2}O (2), [(UO{sub 2}){sub 2}(1,5-nds)(OH){sub 2}(bipy){sub 2}].bipy (3) and [(UO{sub 2}){sub 2}(1,5-nds)(OH){sub 2}(phen){sub 2}] (4) were obtained, in which doubly hydroxide-bridged uranyl dimers are assembled into one-dimensional (1D) chains by bis(unidentate) disulfonate ligands. Complex [Cu(bipy){sub 2}Cl][UO{sub 2}(2,7-nds)(OH)].H{sub 2}O (5) displays anionic, two-dimensional (2D) sheets in which unidentate/O,O{sup '}-bridging disulfonate ligands link hydroxide-bridged uranyl dimers. In the additional presence of cucurbit[6]uril (CB6), complex [(UO{sub 2}){sub 4}Na{sub 4}(2,7-nds){sub 2}(CB6)Cl{sub 4}O{sub 2}(H{sub 2}O){sub 10}].5H{sub 2}O (6) crystallizes as a 3D framework of intricate architecture, with bis(μ{sub 3}-oxo)-bridged uranyl tetranuclear moieties connected to CB6-bound sodium cations by doubly O,O{sup '}-bridging disulfonates. Complexes 2 and 4 display intense and well-resolved uranyl emission in the solid state, while nearly complete quenching is observed in 3 and 5. (copyright 2017 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim)

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.

Thermal decomposition of ammonium diuranate, uranyl nitrate hexahydrate and uranyl peroxide

International Nuclear Information System (INIS)

Yulianto, T.; Mutiara, E.

2011-01-01

The behaviors of three types of starting powder had been investigated during their thermal decomposition processes in nitrogen, air, and hydrogen. The powder types were the products of uranyl nitrate precipitation, i.e. ADU (ammonium diuranate), UNH (uranyl nitrate hexahydrate), and UPO (uranyl peroxide). The objective of the investigation was to find out the best atmosphere that would result in good quality powder in a thermal decomposition process with the lowest temperature and the shortest period of time in order to reduce the cost of UO 2 powder preparation. Before the thermal decomposition process was initiated, all powder types were characterized for their crystal structures. The investigation was conducted by TG-DTA instrument at temperature up to 800°C and the heating rate of 10°C/minute. The crystal structures were identified by X-Ray Diffractometer with Cu-Ka radiation. The specific surface area of the powder was also observed using BET method, especially for the powder that underwent the process in hydrogen heated up to 800°C. The Results showed that the process took place faster in hydrogen, and UNH required lower thermal decomposition temperature in relations with other types of powder. (author)

EXTRACTION OF URANYL NITRATE FROM AQUEOUS SOLUTIONS

Science.gov (United States)

Furman, N.H.; Mundy, R.J.

1957-12-10

An improvement in the process is described for extracting aqueous uranyl nitrate solutions with an organic solvent such as ether. It has been found that the organic phase will extract a larger quantity of uranyl nitrate if the aqueous phase contains in addition to the uranyl nitrate, a quantity of some other soluble nitrate to act as a salting out agent. Mentioned as suitable are the nitrates of lithium, calcium, zinc, bivalent copper, and trivalent iron.

Splitting of the luminescent excited state of the uranyl ion

International Nuclear Information System (INIS)

Flint, C.D.; Sharma, P.; Tanner, P.A.

1982-01-01

The luminescence spectra of some uranyl compounds has been studied. It has been proposed that the splitting of the luminescent excited state of the uranyl ion is due to a descent in symmetry experienced by the uranyl ion when it is placed in a crystal field. In recent years there has been developed a highly successful model of the electronic structure of the uranyl ion. In this paper the authors use this model to interpret the luminescence spectra of a variety of uranyl compounds

On uranyl phosphites

International Nuclear Information System (INIS)

Avduevskaya, K.A.; Ragulina, N.B.; Rozanov, I.A.; Koval', E.M.

1978-01-01

The medium and single-substituted uranyl phosphites of the UO 2 HPO 3 x 3H 2 O and UO 2 (H 2 PO 3 ) 2 x3H 2 O composition were separated in crystal state for the first time. The medium phosphite is fully dehydrated above H 2 SO 4 , intermediate hydrates not being formed. Waterless phosphite decomposes at the temperature above 360 deg C into the mixture of uranium and uranyl phosphates, hydrogen being liberated. The thermal decomposition of single-substituted phosphite starts at the temperature above 150 deg C and is accompanied by the full reduction of uranium up to U(4). The product of calcination is identified as cubic UP 2 O 7

A protein engineered to bind uranyl selectively and with femtomolar affinity

Science.gov (United States)

Zhou, Lu; Bosscher, Mike; Zhang, Changsheng; Özçubukçu, Salih; Zhang, Liang; Zhang, Wen; Li, Charles J.; Liu, Jianzhao; Jensen, Mark P.; Lai, Luhua; He, Chuan

2014-03-01

Uranyl (UO22+), the predominant aerobic form of uranium, is present in the ocean at a concentration of ~3.2 parts per 109 (13.7 nM) however, the successful enrichment of uranyl from this vast resource has been limited by the high concentrations of metal ions of similar size and charge, which makes it difficult to design a binding motif that is selective for uranyl. Here we report the design and rational development of a uranyl-binding protein using a computational screening process in the initial search for potential uranyl-binding sites. The engineered protein is thermally stable and offers very high affinity and selectivity for uranyl with a Kd of 7.4 femtomolar (fM) and >10,000-fold selectivity over other metal ions. We also demonstrated that the uranyl-binding protein can repeatedly sequester 30-60% of the uranyl in synthetic sea water. The chemical strategy employed here may be applied to engineer other selective metal-binding proteins for biotechnology and remediation applications.

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

Quasirelativistic pseudopotential study of species isoelectronic to uranyl and the equatorial coordination of uranyl

International Nuclear Information System (INIS)

Pyykkoe, P.; Li, J.; Runeberg, N.

1994-01-01

The calculated trends of geometries and vibrational frequencies of several uranyl isoelectronic species, like the known NUN and CUO, and the unknown CUN - , NUO + , and NUF 2+ , are reported. The NUN and CUO results support the matrix spectroscopic assignments. The simplest example of equatorial coordination to uranyl is the C 2d species UO 3 . Its calculated vibrational frequencies also support matrix spectroscopic ones. We earlier suggested that the large range of uranyl bond lengths in UO 6 6- -type systems could be interpreted in terms of a open-quotes frozen, soft e g vibrational modeclose quotes. Further studies on UF 6 , U(OH) 6 , [(OUO)(F eq ) n ] (n-2) -, [(OUO)(NO 3 ) 3 ] - , and [(OUO)(CO 3 ) 3 ] 4- show only small variation of R ax as function of R eq . Thus, the all-oxide case is a special one, where all ligands are capable of single and multiple bonding. 44 refs., 10 figs., 7 tabs

Determination of uranyl ion by potentiometric titration using an uranyl-selective electrode

International Nuclear Information System (INIS)

Nassory, N.S.

1990-01-01

A potentiometric titration of uranyl ion is described using an uranyl selective electrode based on a membrane containing a complex of UO 2 -bis[di-4-(1,1,3,3-tetramethylbutyl)phenyl phosphate] as an ion-exchanger and tritolyl phosphate as a solvent mediator. The titrations were carried out with various titrants: Sodium hydroxide, potassium fluoride and sodium salts of acetate, oxalate and citrate. The equivalence points were determined by Gran's method. Good results were obtained by using sodium oxalate as a titrant for the determination of uranium in several samples of ammonium diuranate. The results were quite comparable with those obtained by X-ray fluorescence spectrometry. (orig.)

Thermodynamic properties of actinide complexes. Part 5: Uranyl(VI)-thioglycolate system; thorium(IV)-glycolate and -thioglycolate systems

Energy Technology Data Exchange (ETDEWEB)

di Bernardo, P; Roncari, E; Mazzi, U; Bettella, F [Padua Univ. (Italy). Istituto di Chimica Generale ed Inorganica; Consiglio Nazionale delle Ricerche, Padua (Italy). Lab. di Chimica e Tecnologia dei Radioelementi); Magon, L [Ferrara Univ. (Italy). Istituto Chimico

1978-04-01

The changes in free energy, enthalpy and entropy for the formation of uranyl(VI)-thioglycolate, thorium(IV)-glycolate and -thioglycolate complexes have been determined. The changes in free energy were calculated from the stability constants obtained from a potentiometric determination of the concentration of free hydrogen ion, using a glass or quinhydrone electrode. The enthalpy values were measured calorimetrically. The measurements were performed at 25.0/sup 0/C in an aqueous sodium perchlorate medium with the total sodium concentration equal to 100 M. A comparison of the magnitude of the enthalpy and entropy changes for the various systems gives additional support of the view that the thioglycolate acts as a monodentate ligand while the glycolate forms chelate rings.

The dehydration of uranyl nitrate hexahydrate

International Nuclear Information System (INIS)

Badalov, A.; Kamalov, D.D.; Khamidov, B.O.; Mirsaidov, I.U.; Eshbekov, N.R.

2010-01-01

Present article is devoted to study of dehydration process of uranyl nitrate hexahydrate. The dehydration process of uranyl nitrate hexahydrate was studied by means of tensimeter method with membrane zero-manometer. The research was carried out under equilibrium conditions. It was defined that in studied temperature ranges (300-450 K) the dehydration process of UO_2(NO_3)_2 has a three stage character.

Infrared Spectroscopy of Discrete Uranyl Anion Complexes

International Nuclear Information System (INIS)

Groenewold, G. S.; Gianotto, Anita K.; McIIwain, Michael E.; Van Stipdonk, Michael J.; Kullman, Michael; Moore, David T.; Polfer, Nick; Oomens, Jos; Infante, Ivan A.; Visscher, Lucas; Siboulet, Bertrand; De Jong, Wibe A.

2008-01-01

The Free-Electron Laser for Infrared Experiments (FELIX) w 1 as used to study the wavelength-resolved multiple photon photodissociation of discrete, gas phase uranyl (UO2 2 2+) complexes containing a single anionic ligand (A), with or without ligated solvent molecules (S). The uranyl antisymmetric and symmetric stretching frequencies were measured for complexes with general formula [UO2A(S)n]+, where A was either hydroxide, methoxide, or acetate; S was water, ammonia, acetone, or acetonitrile; and n = 0-3. The values for the antisymmetric stretching frequency for uranyl ligated with only an anion ([UO2A]+) were as low or lower than measurements for [UO2]2+ ligated with as many as five strong neutral donor ligands, and are comparable to solution phase values. This result was surprising because initial DFT calculations predicted values that were 30-40 cm-1 higher, consistent with intuition but not with the data. Modification of the basis sets and use of alternative functionals improved computational accuracy for the methoxide and acetate complexes, but calculated values for the hydroxide were greater than the measurement regardless of the computational method used. Attachment of a neutral donor ligand S to [UO2A]+ produced [UO2AS]+, which produced only very modest changes to the uranyl antisymmetric stretch frequency, and did not universally shift the frequency to lower values. DFT calculations for [UO2AS]+ were in accord with trends in the data, and showed that attachment of the solvent was accommodated by weakening of the U-anion bond as well as the uranyl. When uranyl frequencies were compared for [UO2AS]+ species having different solvent neutrals, values decreased with increasing neutral nucleophilicity

The interaction of uranyl ions with inorganic pyrophosphatase from baker's yeast

International Nuclear Information System (INIS)

Bienwald, B.; Heitmann, P.

1978-01-01

The interaction of uranyl ions with inorganic pyrophosphatase from baker's yeast was investigated by measurement of their effect on the protein fluorescence. Fluorescence titrations of the native enzyme with uranyl nitrate show that there is a specific binding of uranyl ions to the enzyme. It was deduced that each subunit of the enzyme binds one uranyl ion. The binding constant was estimated to be in the order of 10 7 M -1 . The enzyme which contains a small number of chemically modified carboxyl groups was not able to bind uranyl ions specifically. The modification of carboxyl groups was carried out by use of a water soluble carbodiimide and the nucleophilic reagent N-(2,4-dinitro-phenyl)-hexamethylenediamine. The substrate analogue calcium pyrophosphate displaced the uranyl ions from their binding sites at the enzyme From the results it is concluded that carboxyl groups of the active site are the ligands for the binding of uranyl ions. (author)

Thermal analysis studies of ammonium uranyl carbonate

International Nuclear Information System (INIS)

Cao Xinsheng; Ma Xuezhong; Wang Fapin; Liu Naixin; Ji Changhong

1988-01-01

The simultaneous thermogravimetry and differential thermal analysis of the ammonium uranyl carbonate powder were performed with heat balance in the following atmosphers: Air, Ar and Ar-8%H 2 . The thermogravimetry and differential thermal analysis curves of the ammonium uranyl carbonate powder obtained from different source were reported and discussed

Infrared spectra of volatile adduct of uranyl pivaloyltrifluoroacetonate with hexamethylphosphorotriamide

International Nuclear Information System (INIS)

Bukhmarina, V.N.; Dushin, R.B.; Sidorenko, G.V.; Suglobov, D.N.

1983-01-01

Adduct of uranyl pivaloyltrifluoroacetonate with hexamethylphosphortriamide (1), sublimated without decomposition and characterized by a high thermal stability, has been synthesized, as well as adducts of uranyl dipivaloylmethanate with hexamethylphosphortriamide (2) and dimethyl sulfoxide (3), sublimated with partial dissociation. IR spectra of crystalline adducts 1-3, their solutions in benzene; gaseous and matrix-isolated adduct 1 have been measured. It is shown that in gaseous phase 1 exists practically completely in non-dissociated form. It is detected that uranyl group in crystalline 1 and 2 and in matrix-isolated 1 in contrast to crystalline 3 and previously studied adducts of uranyl β-diketonates has an asymmetric structure. Strength constants of uranyl group in crystalline 1-3 and matrix-isolated 1 are determined

Thermochemical investigations on uranyl phosphates and arsenates

International Nuclear Information System (INIS)

Barten, H.

1986-11-01

The results are described of a study of the thermochemical stability of anhydrous uranyl phosphates and arsenates. A number of aspects of chemical technological importance are indicated in detail. The synthesized anhydrous uranyl phosphates and arsenates were very hygroscopic, so that experiments on these compounds had to be carried out under moisture-free conditions. Further characterisation of these compounds are given, including a study of their thermal stabilities and phase relations. The uranyl phosphates reduced reversibly at temperatures of the order of 1100 to 1600 0 C. This makes it possible to express their relative stabilities quantitatively, in terms of the oxygen pressures of the reduction reactions. The thermal decomposition of uranyl arsenates did not occur by reduction, as for the phosphates, but by giving off arsenic oxide vapour. The results of measurements of enthalpies of solution led to the determination of the enthalpies of formation, heat capacity and the standard entropies of the uranyl arsenates. The thermochemical functions at high-temperatures could consequently be calculated. Attention is paid to the possible formation of uranium arsenates, whose uranium has a valency lower than six, hitherto not reported in literature. It was not possible to prepare arsenates of tetravalent uranium. However, three new compounds were observed, one of these, UAsO 5 , was studied in some detail. (Auth.)

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)

Uranyl soaps - thermal, electronic and infrared spectral study

International Nuclear Information System (INIS)

Solanki, A.K.; Bhandari, A.M.

1981-01-01

The electronic and infrared spectra and TGA thermogram of uranyl soaps (laurate, mystrate, palmitate and stearate) have been studied. The environment about the UO 2+ 2 ion would comprise two 'short bite' bidentate carboxylate groups and oxygen atoms bridging from adjacent carboxylic molecules. The uranyl soaps have UO 2+ 2 vibronic absorption (approx. equal to 22730 cm -1 ) in the range found for eight coordinate uranyl complexes. The greater resistance to thermal degradation (approx. equal to 300 0 C) of these soaps and their stepwise thermal degradation infer strong metal-ligand interaction. (orig.) [de

Can uranyl complexes encapsulate to carbon nanotubes? A ...

Indian Academy of Sciences (India)

K SRINIVASU

We find that uranyl-aqua complex ([UO2(H2O)5]2+) binds stronger as compared to uranyl-hydroxo-complex .... until the maximum Hellmann–Feynman force on each atom ..... porters and near-infrared agents for selective cancer cell.

Uranyl sulfate irradiations at the Van de Graaff: A means to combat uranyl peroxide precipitation

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); Quigley, Kevin J. [Argonne National Lab. (ANL), Argonne, IL (United States); Brossard, Thomas [Argonne National Lab. (ANL), Argonne, IL (United States); Chemerisov, Sergey D. [Argonne National Lab. (ANL), Argonne, IL (United States); Vandegrift, George F. [Argonne National Lab. (ANL), Argonne, IL (United States)

2017-05-01

As part of an effort to support SHINE Medical Technologies in developing a process to produce Mo-99 by neutron-induced fission, a series of irradiation experiments was performed with a 3 MeV Van de Graaff accelerator to generate high radiation doses in 0.5–2 mL uranyl sulfate solutions. The purpose was to determine what conditions result in uranyl peroxide precipitation and what can be done to prevent its formation. The effects of temperature, dose rate, uranium concentration, and the addition of known catalysts for the destruction of peroxide were determined.

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.

IR spectra and structure of uranyl pivaloyltrifluoroacetylacetonate isolated in argon matrix

International Nuclear Information System (INIS)

Belyaeva, A.A.; Dushin, R.B.; Sidorenko, G.V.; Suglobov, D.N.

1985-01-01

When studying IR absorption spectra of a number of isotopomers of uranyl pivaloyl trifluoroacetonate (UPTFA), isolated in the matrix of argon and dissolved in benzene, and comparing them with the spectra of uranyl hexafluoroacetylacetonate (UHFA) vapours, it has been ascertained, that UPTFA vapours consist of monomers and dimers, and UPTFA solution in benzene - of dimers.It is shown, that the dimers have T-shaped structure, at that, the bond inside the dimer is realized by yl-atom of oxygen of an uranyl ion, included in the equatorial coordination sphere of another uranyl ion. Proofs of the dimer T-like structure distortion in gaseous or matrix-isolated state, as a result of which the difference of the angles between uranyl axes from 90 deg is observed, are given. In the framework of approximated model of isolated uranyl-ion the force constants for all the compounds investigated are calaculted

Electronic structure and properties of uranyl compounds. Problems of electron-donor conception

International Nuclear Information System (INIS)

Glebov, V.A.

1982-01-01

Comparison of the series of the ligand mutual substitution in the uranyl compounds with the ligand series of d-elements and with the uranyl ''covalent model'', is made. The data on ionization potentials of the ligand higher valent levels and on the structure of some uranyl nitrate compounds are considered. It is concluded that the mechanism of the ligand effect on the properties of uranyl grouping is more complex, than it is supposed in the traditional representations on the nature of electron-donor interactions in the uranyl compounds

Densities concentrations of aqueous of uranyl nitrate solutions

International Nuclear Information System (INIS)

Rodrigo Otero, A.; Rodriguez Hernandez, B.; Fernandez Rodriguez, L.

1966-01-01

The ratio density-concentration of aqueous uranyl nitrate solutions expressed as U 3 O 8 grams/liter, U grams/liter and hexahydrate uranyl nitrate weight percent at different temperatures, are established. Experimental values are graphically correlated and compared whit some published data. (Author) 2 refs

Photochemical reduction of uranyl ion by acetonitrile and propionitrile

International Nuclear Information System (INIS)

Brar, A.S.; Chander, R.; Sandhu, S.S.

1979-01-01

The photochemical reduction of uranyl ion by acetonitrile, propionitrile, benzonitrile, phenylacetonitrile, cyanoacetic acid and malononitrile in aqueous or aq. acetone medium using radiations >= 400 nm from a medium pressure mercury vapour lamp has been investigated. Except acetonitrile and propionitrile all other nitriles fail to bring about the reduction of uranyl ion. The reduction with aceto- and propionitriles has been found to obey pseudo-first order kinetics. The magnitude of rate of reduction with propionitrile is higher than that with acetonitrile. The pseudo-first order rate constants and quenching constant have been calculated from the kinetic data. It has been found that physical and chemical quenching compete with each other. The plot of reciprocal of quantum yield versus reciprocal (nitrile) is linear with a small intercept on the ordinate axis. Absorption spectra of uranyl ion in pure water, in the presence of acid and in the presence of acid+nitrile reveal that there is no ground state interaction between uranyl ion and the nitrile. A mechanism of photochemical reduction of uranyl ion based on α-hydrogen abstraction from the nitrile has been proposed. (auth.)

Raman spectral titration method: an informative technique for studying the complexation of uranyl with uranyl(vi)-DPA/oxalate systems as examples.

Science.gov (United States)

Liu, Qian; Zhang, Qianci; Yang, Suliang; Zhu, Haiqiao; Liu, Quanwei; Tian, Guoxin

2017-10-10

The Raman band at about 870 cm -1 originating from the symmetric stretch vibration (ν 1 ) of uranyl, UO 2 2+ , has proven to be very informative for investigating the complexation of uranyl using perchlorate or nitrate of known concentration as internal standards. The concentration of uranyl can be conveniently calculated by using the ratio of the directly read band intensities of uranyl and the added reference, ClO 4 - , with a factor of 1.72. While with NO 3 - of concentration lower than 1.8 M as the reference, a factor of 0.85 should be used. Furthermore, with added internal standards, the linear relationship between the Raman intensity and the concentration of the corresponding species is illustrated by the spectral titration of U(vi) with a very strong ligand, dipicolinic acid (DPA); and the application of a spectral titration method with Raman spectroscopy in studying the complexation of uranyl is demonstrated by the titration of U(vi) with oxalate. The stepwise changes in the Raman shift of 18, 17, and 6 cm -1 , corresponding to the three oxalate anions successively bonding to UO 2 2+ , imply that the coordination modes are different. In the 1 : 1 and 1 : 2 ratios of metal to ligand complexes, the oxalate anions bond to the uranyl ion in side-on bidentate mode, but in the 1 : 3 complex the third oxalate bonds in head-on mode, which is much weaker than the first two.

Synthesis and characterization of heterometallic uranyl pyridinedicarboxylate compounds

Science.gov (United States)

Jayasinghe, Ashini S.; Payne, Maurice K.; Forbes, Tori Z.

2017-10-01

The incorporation of transition metals into hybrid uranyl materials can result in more diverse structural topologies and variations in physical and chemical properties. To explore the impact of transition metals on the uranyl cation, five uranium containing bimetallic chain compounds, [(UO2)M(PDC)2(H2O)4]·4(H2O) (PDC = 2,6 pyridinedicarboxylate; M = Ni2+, Co2+, Fe2+, Zn2+, and Cu2+) were synthesized by evaporation of aqueous solutions at room temperature. The uranyl cation is complex by two PDC ligands and the transition metal cations bond to the complex to form a one-dimensional chain topology. The presence of the transition metal leads to the presence of a stronger uranyl oxo bonds as shown by the single-crystal X-ray diffraction data and the Raman spectra. Solid state diffuse reflectance UV/Visible spectra confirmed the presence of the transition metals in the structure by the broad bands that appeared at relevant wavelengths.

[Bifunctional chelates of Rh-105, Au-199, and other metallic radionuclides as potential radiotherapeutic agents

International Nuclear Information System (INIS)

1991-01-01

Progress during this period is reported under the following headings: Diethylenetriamine based and related bifunctional chelating agents and their complexation with Rh-105, Au-198, Pd-109, cu-67, In-111, and Co-57; studies of Pd-109, Rh-105 and Tc-99m with bifunctional chelates based on phenylenediamine; establishment of an appropriate protein assay method for conjugated proteins; studies of new bifunctional Bi, Tri and tetradentate amine oxime ligands with Rh-105; IgG and antibody B72.3 conjugation studies by HPLC Techniques with bifunctional metal chelates; and progress on ligand systems for Au(III)

[Bifunctional chelates of Rh-105, Au-199, and other metallic radionuclides as potential radiotherapeutic agents

Energy Technology Data Exchange (ETDEWEB)

1991-12-31

Progress during this period is reported under the following headings: Diethylenetriamine based and related bifunctional chelating agents and their complexation with Rh-105, Au-198, Pd-109, cu-67, In-111, and Co-57; studies of Pd-109, Rh-105 and Tc-99m with bifunctional chelates based on phenylenediamine; establishment of an appropriate protein assay method for conjugated proteins; studies of new bifunctional Bi, Tri and tetradentate amine oxime ligands with Rh-105; IgG and antibody B72.3 conjugation studies by HPLC Techniques with bifunctional metal chelates; and progress on ligand systems for Au(III).

(Bifunctional chelates of Rh-105, Au-199, and other metallic radionuclides as potential radiotherapeutic agents)

Energy Technology Data Exchange (ETDEWEB)

1991-01-01

Progress during this period is reported under the following headings: Diethylenetriamine based and related bifunctional chelating agents and their complexation with Rh-105, Au-198, Pd-109, cu-67, In-111, and Co-57; studies of Pd-109, Rh-105 and Tc-99m with bifunctional chelates based on phenylenediamine; establishment of an appropriate protein assay method for conjugated proteins; studies of new bifunctional Bi, Tri and tetradentate amine oxime ligands with Rh-105; IgG and antibody B72.3 conjugation studies by HPLC Techniques with bifunctional metal chelates; and progress on ligand systems for Au(III).

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.

Uranyl Sulfate Nanotubules Templated by N-phenylglycine

Directory of Open Access Journals (Sweden)

Oleg I. Siidra

2018-04-01

Full Text Available The synthesis, structure, and infrared spectroscopy properties of the new organically templated uranyl sulfate Na(phgH+7[(UO26(SO410](H2O3.5 (1, obtained at room temperature by evaporation from aqueous solution, are reported. Its structure contains unique uranyl sulfate [(UO26(SO410]8− nanotubules templated by protonated N-phenylglycine (C6H5NH2CH2COOH+. Their internal diameter is 1.4 nm. Each of the nanotubules is built from uranyl sulfate rings sharing common SO4 tetrahedra. The template plays an important role in the formation of the complex structure of 1. The aromatic rings are stacked parallel to each other due to the effect of π–π interaction with their side chains extending into the gaps between the nanotubules.

Photochemical reduction of uranyl ion with triphenylphosphine

International Nuclear Information System (INIS)

Brar, A.S.; Sidhu, M.S.; Sandhu, S.S.

1981-01-01

Photochemical reduction of uranyl ion with triphenylphosphine has been studied in acetone-water medium in the presence of sulphuric acid at 346nm, 400nm and 434nm wavelengths. The photochemical reduction is of second order and increases with increase in hydrogen ion concentration. Absorption spectra of uranyl ion in acidic medium and uranyl ion with triphenylphosphine do not show any ground state complex formation. The value of quantum yield increases with the wavelength of the radiation increase from 346 to 434nm. Plots of reciprocal of quantum yield for the formation of U(IV) versus reciprocal [triphenylphosphine] are linear. Products characterized by UV and visible, IR and TLC show the formation of U(IV) and triphenylphosphine oxide. On the basis of above observations mechanism of the photochemical reduction has been proposed. (author)

Benchmarking uranyl peroxide capsule chemistry in organic media

Energy Technology Data Exchange (ETDEWEB)

Neal, Harrison A.; Nyman, May [Department of Chemistry, Oregon State University, Corvallis, OR (United States); Szymanowski, Jennifer; Fein, Jeremy B.; Burns, Peter C. [Department of Civil and Environmental Engineering and Earth Sciences, University of Notre Dame, Notre Dame, IN (United States)

2017-01-03

Uranyl peroxide capsules are a recent addition to polyoxometalate (POM) chemistry. Ten years of development has ensued only in water, while transition metal POMs are commonly exploited in aqueous and organic media, controlled by counterions or ligation to render the clusters hydrophilic or hydrophobic. Here, new uranyl POM behavior is recognized in organic media, including (1) stabilization and immobilization of encapsulated hydrophilic countercations, identified by Li nuclear magnetic resonance (NMR) spectroscopy, (2) formation of new cluster species upon phase transfer, (3) extraction of uranyl clusters from different starting materials including simulated spent nuclear fuel, (4) selective phase transfer of one cluster type from a mixture, and (5) phase transfer of clusters from both acidic and alkaline media. The capsule morphology of the uranyl POMs renders accurate characterization by X-ray scattering, including the distinction of geometrically similar clusters. Compositional analysis of the aqueous phase post-extraction provided a quantitative determination of the ion exchange process that enables transfer of the clusters into the organic phase. Preferential partitioning of uranyl POMs into organic media presents new frontiers in metal ion behavior and chemical reactions in the confined space of the cluster capsules in hydrophobic media, as well as the reactivity of clusters at the organic/aqueous interface. (copyright 2017 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim)

Benchmarking uranyl peroxide capsule chemistry in organic media

International Nuclear Information System (INIS)

Neal, Harrison A.; Nyman, May; Szymanowski, Jennifer; Fein, Jeremy B.; Burns, Peter C.

2017-01-01

Uranyl peroxide capsules are a recent addition to polyoxometalate (POM) chemistry. Ten years of development has ensued only in water, while transition metal POMs are commonly exploited in aqueous and organic media, controlled by counterions or ligation to render the clusters hydrophilic or hydrophobic. Here, new uranyl POM behavior is recognized in organic media, including (1) stabilization and immobilization of encapsulated hydrophilic countercations, identified by Li nuclear magnetic resonance (NMR) spectroscopy, (2) formation of new cluster species upon phase transfer, (3) extraction of uranyl clusters from different starting materials including simulated spent nuclear fuel, (4) selective phase transfer of one cluster type from a mixture, and (5) phase transfer of clusters from both acidic and alkaline media. The capsule morphology of the uranyl POMs renders accurate characterization by X-ray scattering, including the distinction of geometrically similar clusters. Compositional analysis of the aqueous phase post-extraction provided a quantitative determination of the ion exchange process that enables transfer of the clusters into the organic phase. Preferential partitioning of uranyl POMs into organic media presents new frontiers in metal ion behavior and chemical reactions in the confined space of the cluster capsules in hydrophobic media, as well as the reactivity of clusters at the organic/aqueous interface. (copyright 2017 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim)

Aggregation-induced emission active tetraphenylethene-based sensor for uranyl ion detection

Energy Technology Data Exchange (ETDEWEB)

Wen, Jun; Huang, Zeng; Hu, Sheng [Institute of Nuclear Physics and Chemistry, China Academy of Engineering Physics, Mianyang, 621900, Sichuan Province (China); Li, Shuo, E-mail: lishuo@cqut.edu.cn [School of Chemical Engineering, Chongqing University of Technology, Chongqing 400054 (China); Li, Weiyi, E-mail: weiyili@mail.xhu.edu.cn [School of Science, Xihua University, Chengdu, Sichuan, 610065 (China); Wang, Xiaolin, E-mail: xlwang@caep.cn [Institute of Nuclear Physics and Chemistry, China Academy of Engineering Physics, Mianyang, 621900, Sichuan Province (China)

2016-11-15

Highlights: • A novel AIE fluorescent sensor for the detection of uranyl has been developed. • TPE-T is capable of visually distinguish UO{sub 2}{sup 2+} among many metals owing to the AIE phenomenon. • TPE-T showed a wide effective pH range, high selectivity and good anti-interference qualities. • TPE-T showed good accuracy in the determination of uranyl in river water. - Abstract: A novel tetraphenylethene-based fluorescent sensor, TPE-T, was developed for the detection of uranyl ions. The selective binding of TPE-T to uranyl ions resulted in a detectable signal owing to the quenching of its aggregation-induced emission. The developed sensor could be used to visually distinguish UO{sub 2}{sup 2+} from lanthanides, transition metals, and alkali metals under UV light; the presence of other metal ions did not interfere with the detection of uranyl ions. In addition, TPE-T was successfully used for the detection of uranyl ions in river water, illustrating its potential applications in environmental systems.

Technetium-99m labelling of monoclonal antibodies for in vivo radioimmunodiagnostic use

International Nuclear Information System (INIS)

Beyers, M.

1988-01-01

The strong chelating agent diethylenetriaminepentaacetate (DTPA), either as the bicyclic or as the mixed anhydride, is most commonly used to link Tc-99m to proteinaceous compounds. A method for the batch production of DTPA-labelled antibody kits as well as a novel method of DTPA chelation of unpurified ascites fluid is given. Loss of immunoreactivity and in vivo stability occurs with this method. That DTPA conjugation is not the ideal method of labelling, is borne out by the fact that Hnatowich - a pioneer of DTPA-protein chelating - changed to an avidin-biotin labelling system. Modifications of the carbohydrate moiety have also been attempted. High molecular mass polymers with chelate-linkage to the antibodies can bind up to 150 di- or trivalent ions per mole without a loss in antigen-binding activity. Other than DTPA, several chelating agents such as bisthiosemicarbazones, metallothionein and diamide dimercaptide ligands may be used. The simple treatment of a proteinaceous substance with a disulpide-reducing agent, followed by exposure of the reduced protein to a suitable radionuclide, leads to a promising stable radiolabelled product. A Tc-99m-labelled antibody is, subject to FDA approval, scheduled for released by a Kodak-financed company in the near future

Evaluation of the stability of uranyl peroxo-carbonato complex ions in carbonate media at different temperatures

International Nuclear Information System (INIS)

Kim, Kwang-Wook; Lee, Keun-Young; Chung, Dong-Yong; Lee, Eil-Hee; Moon, Jei-Kwon; Shin, Dong-Woo

2012-01-01

Highlights: ► The stability of peroxide in uranyl peroxo carbonato complex solutions with different temperatures was characterized. ► The decomposition rate of uranyl peroxo carbonato complex ion to uranyl tris-carbonato complex ion was observed to increase with temperature ► The decomposition kinetics of uranyl peroxo carbonato complex ions was evaluated by absorption and Raman spectroscopies. ► A precipitate of uranyl peroxo carbonato complex solution was evaluated with XRD. - Abstract: This work studied the stability of peroxide in uranyl peroxo carbonato complex ions in a carbonate solution with hydrogen peroxide using absorption and Raman spectroscopies, and evaluated the temperature dependence of the decomposition characteristics of uranyl peroxo carbonato complex ions in the solution. The uranyl peroxo carbonato complex ions self-decomposed more rapidly into uranyl tris-carbonato complex ions in higher temperature carbonate solutions. The concentration of peroxide in the solution without free hydrogen peroxide represents the concentration of uranyl peroxo carbonato complex ions in a mixture of uranyl peroxo carbonato complex and uranyl tris-carbonato complex ions. The self-decomposition of the uranyl peroxo carbonato complex ions was a first order reaction, and its activation energy was evaluated to be 7.144 × 10 3 J mol −1 . The precipitation of sodium uranium oxide hydroxide occurred when the amount of uranyl tris-carbonato complex ions generated from the decomposition of the uranyl peroxo carbonato complex ions exceeded the solubility of uranyl tris-carbonato ions in the solution at the solution temperature.

Sorption of uranyl ions on hydrous silicon dioxide

International Nuclear Information System (INIS)

Lieser, K.H.; Quandt-Klenk, S.; Thybusch, B.

1992-01-01

Sorption of uranyl ions on SiO 2 .χH 2 O (silica gel) is investigated in absence and in presence of carbonate as function of pH. The curves obtained are very similar to those observed for sorption of uranyl ion on TiO 2 .χH 2 O, indicating the dominating influence of the uranium species in solution. Between pH 2 and 5 the sorption ratio R s increases with hydrolysis of uranyl ions (formation of UO 2 OH + ), around pH 7 it is nearly independent of pH, and at higher pH it decreases again. The equilibrium constants are calculated for these ranges. In presence of carbonate R s decreases drastically above pH 6, due to the formation of carbonato complexes in solution. Sorption of uranyl ions on SiO 2 .χH 2 O, on TiO 2 .χH 2 O, and on cryst. SiO 2 and Al 2 O 3 is compared. The problems of 'surface complexation' modelling are discussed. (orig.)

Photochemical reduction of uranyl ion with amides

International Nuclear Information System (INIS)

Brar, A.S.; Chander, R.; Sandhu, S.S.

1981-01-01

The photochemical reduction of uranyl ion by formamide, acetamide, propionamide, butyramide, iso butyramids, n-methylformamide, N, N-dimethylformamide and N, N-diethylformamide in aqueous medium using radiation >= 380 nm from a medium pressure mercury vapour lamp has been investigated. The reduction with the said amides has been found to obey pseudo first order kinetics. The magnitude of the rate of reduction for the simple amides has been found to follow the following order formamide > isobutyramide approx. butyramide > propionamide > acetamide while the rate order for N-alkylformamides compared with that of the formamide has been found to be formamide > N-methylformamide > N,N-diethylformamide approx. N,N-dimethylformamide. The pseudo first order rate constants and quenching constants have been found from the kinetic data. It has been found that physical and chemical quenching compete with each other. Plots of reciprocal of quantum yields versus reciprocal [amide] have been found to be linear with intercepts on the ordinate axis. Absorption spectra of uranyl ion in doubly distilled water, in the presence of acid and in the presence of acid and amide reveal that there is no ground state interaction between uranyl ion and the amide. A mechanism of photoreduction of uranyl ion with amides has been proposed. (author)

Evaluation of the stability of uranyl peroxo-carbonato complex ions in carbonate media at different temperatures

Energy Technology Data Exchange (ETDEWEB)

Kim, Kwang-Wook, E-mail: nkwkim@kaeri.re.kr [Korea Atomic Energy Research Institute, 1045 Daedeok daero, Yuseong, Daejeon 305-353 (Korea, Republic of); Lee, Keun-Young; Chung, Dong-Yong; Lee, Eil-Hee; Moon, Jei-Kwon [Korea Atomic Energy Research Institute, 1045 Daedeok daero, Yuseong, Daejeon 305-353 (Korea, Republic of); Shin, Dong-Woo [Gyeongsang National University, 900 Gajwa, Jinju 660-701 (Korea, Republic of)

2012-09-30

Highlights: Black-Right-Pointing-Pointer The stability of peroxide in uranyl peroxo carbonato complex solutions with different temperatures was characterized. Black-Right-Pointing-Pointer The decomposition rate of uranyl peroxo carbonato complex ion to uranyl tris-carbonato complex ion was observed to increase with temperature Black-Right-Pointing-Pointer The decomposition kinetics of uranyl peroxo carbonato complex ions was evaluated by absorption and Raman spectroscopies. Black-Right-Pointing-Pointer A precipitate of uranyl peroxo carbonato complex solution was evaluated with XRD. - Abstract: This work studied the stability of peroxide in uranyl peroxo carbonato complex ions in a carbonate solution with hydrogen peroxide using absorption and Raman spectroscopies, and evaluated the temperature dependence of the decomposition characteristics of uranyl peroxo carbonato complex ions in the solution. The uranyl peroxo carbonato complex ions self-decomposed more rapidly into uranyl tris-carbonato complex ions in higher temperature carbonate solutions. The concentration of peroxide in the solution without free hydrogen peroxide represents the concentration of uranyl peroxo carbonato complex ions in a mixture of uranyl peroxo carbonato complex and uranyl tris-carbonato complex ions. The self-decomposition of the uranyl peroxo carbonato complex ions was a first order reaction, and its activation energy was evaluated to be 7.144 Multiplication-Sign 10{sup 3} J mol{sup -1}. The precipitation of sodium uranium oxide hydroxide occurred when the amount of uranyl tris-carbonato complex ions generated from the decomposition of the uranyl peroxo carbonato complex ions exceeded the solubility of uranyl tris-carbonato ions in the solution at the solution temperature.

Aggregation-induced emission active tetraphenylethene-based sensor for uranyl ion detection.

Science.gov (United States)

Wen, Jun; Huang, Zeng; Hu, Sheng; Li, Shuo; Li, Weiyi; Wang, Xiaolin

2016-11-15

A novel tetraphenylethene-based fluorescent sensor, TPE-T, was developed for the detection of uranyl ions. The selective binding of TPE-T to uranyl ions resulted in a detectable signal owing to the quenching of its aggregation-induced emission. The developed sensor could be used to visually distinguish UO2(2+) from lanthanides, transition metals, and alkali metals under UV light; the presence of other metal ions did not interfere with the detection of uranyl ions. In addition, TPE-T was successfully used for the detection of uranyl ions in river water, illustrating its potential applications in environmental systems. Copyright © 2016 Elsevier B.V. All rights reserved.

The state of uranyl ions in water-dioxane solvent mixtures

International Nuclear Information System (INIS)

Geipel, G.; Nebel, D.; Baraniak, L.

1985-01-01

A comparison of the spectra of uranyl ions in HCl and dioxane solutions leads to the conclusion that dioxane promotes complex formation. The investigation of spectra showed that taking into account the hydrolysis of uranyl ions in dioxane containing solutions, two successive equilibrium reactions take place. The formation constants were determined. Conductivity measurements confirmed the spectrophotometrically determined equilibria. In solutions containing up to 60 % dioxane there is no incorporation of dioxane in the solvating envelope of the uranyl ion. (author)

Evaluation of the stability of uranyl peroxo-carbonato complex ions in carbonate media at different temperatures.

Science.gov (United States)

Kim, Kwang-Wook; Lee, Keun-Young; Chung, Dong-Yong; Lee, Eil-Hee; Moon, Jei-Kwon; Shin, Dong-Woo

2012-09-30

This work studied the stability of peroxide in uranyl peroxo carbonato complex ions in a carbonate solution with hydrogen peroxide using absorption and Raman spectroscopies, and evaluated the temperature dependence of the decomposition characteristics of uranyl peroxo carbonato complex ions in the solution. The uranyl peroxo carbonato complex ions self-decomposed more rapidly into uranyl tris-carbonato complex ions in higher temperature carbonate solutions. The concentration of peroxide in the solution without free hydrogen peroxide represents the concentration of uranyl peroxo carbonato complex ions in a mixture of uranyl peroxo carbonato complex and uranyl tris-carbonato complex ions. The self-decomposition of the uranyl peroxo carbonato complex ions was a first order reaction, and its activation energy was evaluated to be 7.144×10(3) J mol(-1). The precipitation of sodium uranium oxide hydroxide occurred when the amount of uranyl tris-carbonato complex ions generated from the decomposition of the uranyl peroxo carbonato complex ions exceeded the solubility of uranyl tris-carbonato ions in the solution at the solution temperature. Copyright © 2012 Elsevier B.V. All rights reserved.

Structure and dynamics of aqueous solution of uranyl ions

International Nuclear Information System (INIS)

Chopra, Manish; Choudhury, Niharendu

2014-01-01

The present work describes a molecular dynamics simulation study of structure and dynamics of aqueous solution of uranyl ions in water. Structural properties of the system in terms of radial distribution functions and dynamical characteristics as obtained through velocity autocorrelation function and mean square displacements have been analyzed. The results for radial distribution functions show the oxygen of water to form the first solvation shell at 2.4 Å around the uranium atom, whereas the hydrogen atoms of water are distributed around the uranium atom with the major peak at around 3.0 Å. Analyses of transport behaviors of ions and water through MSD indicates that the diffusion of the uranyl ion is much less as compared to that of the water molecules. It is also observed that the dynamical behavior of water molecules gets modified due to the presence of uranyl ion. The effect of increase in concentration of uranyl ions on the structure and dynamics of water molecules is also studied

Comparative study of uranyl(VI) and -(V) carbonato complexes in an aqueous solution.

Science.gov (United States)

Ikeda, Atsushi; Hennig, Christoph; Tsushima, Satoru; Takao, Koichiro; Ikeda, Yasuhisa; Scheinost, Andreas C; Bernhard, Gert

2007-05-14

Electrochemical, complexation, and electronic properties of uranyl(VI) and -(V) carbonato complexes in an aqueous Na2CO3 solution have been investigated to define the appropriate conditions for preparing pure uranyl(V) samples and to understand the difference in coordination character between UO22+ and UO2+. Cyclic voltammetry using three different working electrodes of platinum, gold, and glassy carbon has suggested that the electrochemical reaction of uranyl(VI) carbonate species proceeds quasi-reversibly. Electrolysis of UO22+ has been performed in Na2CO3 solutions of more than 0.8 M with a limited pH range of 11.7 < pH < 12.0 using a platinum mesh electrode. It produces a high purity of the uranyl(V) carbonate solution, which has been confirmed to be stable for at least 2 weeks in a sealed glass cuvette. Extended X-ray absorption fine structure (EXAFS) measurements revealed the structural arrangement of uranyl(VI) and -(V) tricarbonato complexes, [UO2(CO3)3]n- [n = 4 for uranyl(VI), 5 for uranyl(V)]. The bond distances of U-Oax, U-Oeq, U-C, and U-Odist are determined to be 1.81, 2.44, 2.92, and 4.17 A for the uranyl(VI) complex and 1.91, 2.50, 2.93, and 4.23 A for the uranyl(V) complex, respectively. The validity of the structural parameters obtained from EXAFS has been supported by quantum chemical calculations for the uranyl(VI) complex. The uranium LI- and LIII-edge X-ray absorption near-edge structure spectra have been interpreted in terms of electron transitions and multiple-scattering features.

Solid solutions of hydrogen uranyl phosphate and hydrogen uranyl arsenate. A family of luminescent, lamellar hosts

International Nuclear Information System (INIS)

Dorhout, P.K.; Rosenthal, G.L.; Ellis, A.B.

1988-01-01

Hydrogen uranyl phosphate, HUO 2 PO 4 x 4H 2 O (HUP), and hydrogen uranyl arsenate, HUO 2 AsO 4 x 4H 2 O (HUAs), form solid solutions of composition HUO 2 (PO 4 ) 1-x (AsO 4 )x (HUPAs), representing a family of lamellar, luminescent solids that can serve as hosts for intercalation chemistry. The solids are prepared by aqueous precipitation reactions from uranyl nitrate and mixtures of phosphoric and arsenic acids; thermogravimetric analysis indicates that the phases are tetrahydrates, like HUP and HUAs. Powder x-ray diffraction data reveal the HUPAs solids to be single phases whose lattice constants increase with X, in rough accord with Vegard's law Spectral shifts observed for the HUPAs samples. Emission from the solids is efficient (quantum yields of ∼ 0.2) and long-lived (lifetimes of ∼ 150 μs), although the measured values are uniformly smaller than those of HUP and HUAs; unimolecular radiative and nonradiative rate constants for excited-state decay of ∼ 1500 and 5000 s -1 , respectively, have been calculated for the compounds. 18 refs., 5 figs., 2 tabs

Thermal decomposition of uranyl sulphate hydrate

International Nuclear Information System (INIS)

Sato, T.; Ozawa, F.; Ikoma, S.

1980-01-01

The thermal decomposition of uranyl sulphate hydrate (UO 2 SO 4 .3H 2 O) has been investigated by thermogravimetry, differential thermal analysis, X-ray diffraction and infrared spectrophotometry. As a result, it is concluded that uranyl sulphate hydrate decomposes thermally: UO 2 SO 4 .3H 2 O → UO 2 SO 4 .xH 2 O(2.5 = 2 SO 4 . 2H 2 O → UO 2 SO 4 .H 2 O → UO 2 SO 4 → α-UO 2 SO 4 → β-UO 2 SO 4 → U 3 O 8 . (author)

Quinoline-8-ol-immobilized Amberlite XAD-4: Synthesis, characterization, and uranyl ion uptake properties suitable for analytical applications

International Nuclear Information System (INIS)

Gladis, Mary J.; Prasada Rao, T.

2002-01-01

Amberlite XAD-4 has been functionalized by coupling it with 5-aminoquinoline-8-ol after acetylation. The resulting resin has been characterized by elemental analysis and IR spectra and has been used for preconcentrating uranyl ions prior to its determination by spectrophotometry. The optimum pH value for quantitative sorption is 4-6, and desorption can be achieved by using 5 mL of 1 mol L -1 HCl. The sorption capacity of the resin is 11.5 mmol g -1 . The effect of various cations and anions on the preconcentration of uranium in conjunction with the determination procedure has been studied and we have found that none of the ions interfere except thorium. The enrichment factor for preconcentration of uranium was found to be 200. Ten replicate determinations of 40 μg of uranium present in 1 L of sample gave a mean absorbance of 0.185 with a relative standard deviation of 2.64%. The detection limit corresponding to three times the standard deviation of the bank was found to be 2 μg L -1 . The validation of the developed preconcentration procedure was carried out by successfully analyzing standard marine sediment reference material. The uranyl content of sediment and soils is estimated by spectrophotometry after its preconcentration with the above chelating resin. (orig.)

Structural contributions to the third-law entropy of uranyl phases

International Nuclear Information System (INIS)

Chen, F.; Ewing, R.C.

1999-01-01

Entropies that are used in geochemical calculations are usually based on calorimetric measurements. However, because of the contributions of neglected residual entropies which cannot be determined by calorimetric measurements, the true third-law entropies for many phases may be quite different from those derived from thermal data. The residual entropies are caused by site-mixing, structural disorder and magnetic spin disorder and may result in a considerable contribution to the third-law entropy of solid phases. Magnetic spin-configurational entropy is not expected to be significant in uranyl phases. However, 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 and the polar H 2 O molecules may occur. Calculations of the ideal site-mixing configurational entropy for some uranyl phases indicate that the residual contributions that arise from substitution and vacancies to the third-law entropies of uranyl phases may be 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 H 2 O groups

Use of uranyl nitrate as a shift reagent in polar and inert solvents

International Nuclear Information System (INIS)

Nosov, B.P.

1988-01-01

This work examines the effect of uranyl nitrate as a shift reagent on the PMR spectra of different organic molecules in polar and inert solvents. In order to identify the coordination site of the uranyl ion, its effect on the spectra of amino acids and acetic or propionic acids in water was compared. It was found that the induced shifts of the protons in the corresponding positions of the different acids after addition of uranyl nitrate agreed to within ±0.01 ppm. When nitrogenous bases such as diethylamine and pyridine were added to solutions of the carboxylic acids with uranyl nitrate, an increase in the induced chemical shift of the resonance signals occurred. These facts suggest the coordination of the uranyl ion with the carboxyl oxygen both for acetic and propionic acids and for amino acids. The authors established that the addition of uranyl nitrate to solutions of organic compounds caused different downfield shifts of the resonance signals from the protons. In polar solvents shifts induced by uranyl nitrate in the PMR spectra of carboxylic acids occur only when nitrogenous bases are added

A study of precipitation from pure solutions of uranyl nitrate; Etude de la precipitaion de solutions pures de nitrate d'uranyle

Energy Technology Data Exchange (ETDEWEB)

Decrop, J; Holder, J; Sauteron, J [Commissariat a l' Energie Atomique, Usine du Bouchet, Service des Lab. de Recherches et de Controle, Saclay (France). Centre d' Etudes Nucleaires

1961-07-01

After its purification by extraction of the uranyl nitrate from the organic solvent, uranium has to be converted into solid form again: uranium trioxide (UO{sub 3}). It can be done either by thermal decomposition of uranyl nitrate or by precipitation of uranium, followed by filtration and calcination. Only the second method has been studied for now at the Bouchet plant. This paper reports the bench-scale and pilot-scale experiments of the studies of the precipitation of pure solutions of uranyl nitrate using ammonia (gaseous or in solution) or ammonium carbonate. These have been carried out at the Bouchet plant. It investigates the chemical aspect (pH, precipitates chemical composition) and the technical aspect of the different ways of precipitation (conditions of precipitation, decantation and filtration of precipitates). (M.P.)

Development of a new radiolabel (lead-203) and new chelating agents for labeling monoclonal anntibodies for imaging

International Nuclear Information System (INIS)

Srivastava, S.C.; Mease, R.C.; Meinken, G.E.; Mausner, L.F.; Steplewski, Z.

1988-01-01

High liver uptake and slow body clearance presently limit the usefulness of 111 In labeled antibodies for tumor imaging. We have investigated 203 Pb as an alternate and better antibody label. The DTPA and cyclohexyl EDTA (CDTA) conjugates of an anticolon carcinoma antibody, 17-1A were labeled (bicyclic anhydride method) with 203 Pb and 111 In with 60 and 90% labeling yields, respectively. The biodistribution of 203 Pb-17-1A conjugates was compared with the corresponding 111 In-labeled preparations and with 203 Pb-DTPA, 203 Pb-nitrate and nonrelevant antibody controls in normal and human tumor (SW948) xenografted nude mice at 24, and 96 hr. Lead-203-labeled CDTA and DTPA antibody conjugates gave similar in vivo distributions. Even though the lead bound to these chelate-antibody conjugates was more labile in serum and in vivo, compared to indium, it cleared much faster from the liver and the whole body. A new series of chelating agents based on the incorporation of a trans-1,2- diaminocyclohexane moiety into the carbon backbone of polyaminocarboxylates is being synthesized. These are expected to provide stronger complexing ability for lead and produce greater in vivo stability. These ligands are also expected to be superior to EDTA and DTPA for labeling antibodies with other radiometals, including indium. 32 refs., 3 tabs

Hydrothermal Phase Relations Among Uranyl Minerals at the Nopal I Analog Site

International Nuclear Information System (INIS)

Murphy, William M.

2007-01-01

Uranyl mineral paragenesis at Nopal I is an analog of spent fuel alteration at Yucca Mountain. Petrographic studies suggest a variety of possible hydrothermal conditions for uranium mineralization at Nopal I. Calculated equilibrium phase relations among uranyl minerals show uranophane stability over a broad range of realistic conditions and indicate that uranyl mineral variety reflects persistent chemical potential heterogeneity. (author)

Syntheses and crystal structures of two novel alkaline uranyl chromates A2(UO2)(CrO4)2 (A=Rb, Cs) with bidentate coordination mode of uranyl ions by chromate anions

International Nuclear Information System (INIS)

Siidra, Oleg I.; Nazarchuk, Evgeny V.; Krivovichev, Sergey V.

2012-01-01

Single crystals of Cs 2 (UO 2 )(CrO 4 ) 2 and Rb 2 (UO 2 )(CrO 4 ) 2 were prepared by solid state reactions. The structures are based upon the [(UO 2 )(CrO 4 ) 2 ] 2− chains. Within the chains, UrO 5 pentagonal bipyramids (Ur=uranyl) form Ur 2 O 8 dimers, which are linked via CrO 4 tetrahedra into one-dimensional chains. The CrO 4 tetrahedra coordinate uranyl ions in both mono- and bidentate fashion, which is unusual for uranyl chromates. The bidentate coordination has a strong influence upon geometrical parameters of both U and Cr coordination polyhedra. The conformation of the chains in 1 and 2 is different due to the different size of the Cs + and Rb + cations. - Graphical abstract: Uranyl chromate chain with monodentate and bidentate coordination mode of uranyl cations by CrO 4 tetrahedra in Cs 2 (UO 2 )(CrO 4 ) 2 . Highlights: ► Single crystals of novel uranyl chromates were prepared by solid state reactions. ► The CrO 4 tetrahedra coordinate uranyl ions in both mono- and bidentate fashion. ►The bidentate coordination has a strong influence upon geometrical parameters.

Potentiometric studies on mixed-ligand chelates of uranyl ion with carboxylic acid phenolic acids

International Nuclear Information System (INIS)

Bandiwadekar, S.P.; Chavar, A.M.

1988-01-01

Mixed ligand complexes of UO 2 2+ with bidentate carboxylic and phenolic acids have been studied potentiometrically at 30 ± 0.1degC and μ=0.2M (NaClO 4 ). 1:1 and 1:2 complexes of UO 2 2+ with phthalic acid (PTHA), maleic acid (MAE), malonic acid (MAL), quinolinic acid (QA), 5-sulphosalicylic acid (5-SSA), salicylic acid (SA), and only 1:1 complexes in the case of mandelic acid (MAD) have been detected. The formation of 1:1:1 mixed ligand complexes has been inferred from simultaneous equilibria in the present study. The values of ΔlogK, Ksub(DAL), Ksub(2LA) or Ksub(2AL) for the ternary complexes have been calculated. The stabilities of mixed ligand complexes depend on the size of the chelate ring and the stabilities of the binary complexes. (author). 15 refs

Synthesis of indium-labeled antibody-chelate conjugates for radioassays

Energy Technology Data Exchange (ETDEWEB)

Gokce, A; Nakamura, R M; Tubis, M; Wolf, W

1982-01-01

A method has been developed to achieve rapid and reproducible complexation of indium to transferrin at pH 7.4. The system consists of nitrilotriacetic acid (NTA) as the intermediate carrier ligand, whose function is to allow the /sup 113/m In ion, in a solution in Tris buffer, pH 7.4, to be transferred rapidly to the specific binding sites on transferrin. Just as in the case of iron, this complexation requires the presence of a synergistic ion such as bicarbonate. The present system can be used to allow the binding of /sup 113/mIn to transferrin when coupled to an antibody. This method has been tested by studying the conjugation of an antibody, the IgG fraction of goat anti-rabbit-IgG, with either transferrin or desferoxamine, using glutaraldehyde as the coupling agent. Optimization in terms of total protein concentration and glutaraldehyde levels lead to products where the specific metal binding capacity of the transferrin moiety remains unchanged, and where the antibody retains 70% of its antigenic activity. The present system can be considered an extension of the ELISA techniques and can be used to determine, by a terminal /sup 113/mIn labeling technique, the level of specific binding of an antibody to its antigen.

Density functional study of uranyl (VI) amidoxime complexes

International Nuclear Information System (INIS)

Chi Fang-Ting; Xiong Jie; Hu Sheng; Xia Xiu-Long; Wang Xiao-Lin; Li Peng; Gao Tao

2012-01-01

Uranyl (VI) amidoxime complexes are investigated using relativistic density functional theory. The equilibrium structures, bond orders, and Mulliken populations of the complexes have been systematically investigated under a generalized gradient approximation (GGA). Comparison of (acet) uranyl amidoxime complexes ([UO 2 (AO) n ] 2−n , 1 ≤ n ≤ 4) with available experimental data shows an excellent agreement. In addition, the U−O(1), U−O(3), C(1)−N(2), and C(3)−N(4) bond lengths of [UO 2 (CH 3 AO) 4 ] 2− are longer than experimental data by about 0.088, 0.05, 0.1, and 0.056 Å. The angles of N(3)−O(3)−U, O(2)−N(1)−C(1), N(3)−C(3)−N(4), N(4)−C(3)−C(4), and C(4)−C(3)−N(3) are different from each other, which is due to existing interaction between oxygen in uranyl and hydrogen in amino group. This interaction is found to be intra-molecular hydrogen bond. Studies on the bond orders, Mulliken charges, and Mulliken populations demonstrate that uranyl oxo group functions as hydrogen-bond acceptors and H atoms in ligands act as hydrogen-bond donors forming hydrogen bonds within the complex

Theoretical insights into the uranyl adsorption behavior on vanadium carbide MXene

Science.gov (United States)

Zhang, Yu-Juan; Zhou, Zhang-Jian; Lan, Jian-Hui; Ge, Chang-Chun; Chai, Zhi-Fang; Zhang, Peihong; Shi, Wei-Qun

2017-12-01

Remediation of the contamination by long-lived actinide wastes is extremely important but also challenging. Adsorption based techniques have attracted much research attention for their potential as low-cost and effective methods to reduce the radioactive waste from solution. In this work, we have investigated the adsorption behavior of uranyl species [with the general form UO2(L1)x(L2)y(L3)z, where L1, L2 and L3 stand for ligands H2O, OH and CO3, respectively] on hydroxylated vanadium carbide V2C(OH)2 MXene nanosheets using density functional theory based simulation methods We find that all studied uranyl species can stably bond to hydroxylated MXene with binding energies ranging from -3.3 to -4.6 eV, suggesting that MXenes could be effective adsorbers for uranyl ions. The strong adsorption is achieved by forming two Usbnd O bonds with the hydroxylated Mxene. In addition, the axial oxygen atoms from the uranyl ions form hydrogen bonds with the hydroxylated V2C, further strengthening the adsorption. We have also investigated the effects of F termination on the uranyl adsorption properties of V2C nanosheets. Usbnd F bonds are in general weaker than Usbnd O bonds on the adsorption site, suggesting that F terminated Mexne is less favorable for uranyl adsorption applications.

Probing uranyl(VI) speciation in the presence of amidoxime ligands using electrospray ionization mass spectrometry.

Science.gov (United States)

Mustapha, Adetayo M; Pasilis, Sofie P

2013-10-15

Extraction processes using poly(acrylamidoxime) resins are being developed to extract uranium from seawater. The main complexing agents in these resins are thought to be 2,6-dihydroxyiminopiperidine (DHIP) and N(1),N(5)-dihydroxypentanediimidamide (DHPD), which form strong complexes with uranyl(VI) at the pH of seawater. It is important to understand uranyl(VI) speciation in the presence of these and similar amidoxime ligands to understand factors affecting uranyl(VI) adsorption to the poly(acrylamidoxime) resins. Experiments were carried out in positive ion mode on a quadrupole ion trap mass spectrometer equipped with an electrospray ionization source. The ligands investigated were DHIP, DHPD, and N(1),N(2)-dihydroxyethanediimidamide (DHED). DHED and DHPD differ only in the number of carbons separating the oxime groups. The effects on the mass spectra of changes in uranyl(VI):ligand ratio, pH, and ligand type were examined. DHIP binds uranyl(VI) more effectively than DHPD or DHED in the pH range investigated, forming ions derived from solution-phase species with uranyl(VI):DHIP stoichiometries of 1:1, 1:2, and 2:3. The 2:3 uranyl(VI):DHIP complex appears to be a previously undescribed solution species. Ions related to uranyl(VI):DHPD complexes were detected in very low abundance. DHED is a more effective complexing agent for uranyl(VI) than DHPD, forming ions having uranyl(VI):DHED stoichiometries of 1:1, 1:2, 1:3, and 2:3. This study presents a first look at the solution chemistry of uranyl(VI)-amidoxime complexes using electrospray ionization mass spectrometry. The appearance of previously undescribed solution species suggests that the uranyl-amidoxime system is a rich and relatively complex one, requiring a more in-depth investigation. Copyright © 2013 John Wiley & Sons, Ltd.

Extraction of uranyl sulfate with primary amine

International Nuclear Information System (INIS)

Mrnka, M.; Bizek, V.; Nekovar, P.; Cizevska, S.; Schroetterova, D.

1984-01-01

PRIMENE JM-T was used for extraction. Its composition was found to approach the general formula C 21 H 43 NH 2 . It was found that the extraction of uranyl sulfate is lower in case of a higher steady-state concentration of sulfuric acid in the aqueous phase. Extraction is accompanied with coextraction of water. The results obtained showed that uranyl sulfate passes into the organic phase by two mechanisms: extraction with amine sulfate and extraction with free amine. A mathematical description of the process was made based on the obtained results. (E.S.)

Evaluation of renal function following administration of ethane-1-hydroxy-1,1-biphosphonate (EHBP) in animals submitted to oral intoxication with uranyl nitrate; Evaluacion de la funcion renal luego de la administracion de etidronato bisodico en animales intoxicados con nitrato de uranilo por via oral

Energy Technology Data Exchange (ETDEWEB)

Martinez, A B; Mandalunis, P M; Bozal, C B; Cabrini, Romulo L; Ubios, A M [Comision Nacional de Energia Atomica, General San Martin (Argentina). Dept. de Radiobiologia

2003-07-01

Workers involved in the processes of extraction, purification and manufacture of uranium of nuclear plants are occupationally exposed to both natural and enriched uranium. Several chelating agents (TIRON, EDTA, BAI, etc.) have been tested in terms of their capacity to sequester uranium before it reaches its target organs. Our laboratory has studied a first generation biphosphonate, ethane-1-hydroxy-1,1-biphosphonate (EHBP). We have shown that treatment with EHBP induces survival rates of 75% and 100% in adult and suckling rats respectively intoxicated with an intraperitoneal injection of uranyl nitrate. There are no data available to date on the renal function following treatment with EBHP to counteract the toxic effects of an oral lethal dose of uranyl nitrate. The aim of the present study was to assay creatininemia and uremia as end-points to assess renal function. The results obtained reveal that the alterations in renal function induced by oral uranyl nitrate intoxication can be reduced at 48 hours and reverted at 14 days by subcutaneous or oral administration of EHBP. (author)

Partitioning of uranyl between ferrihydrite and humic substances at acidic and circum-neutral pH

Science.gov (United States)

Dublet, Gabrielle; Lezama Pacheco, Juan; Bargar, John R.; Fendorf, Scott; Kumar, Naresh; Lowry, Gregory V.; Brown, Gordon E.

2017-10-01

As part of a larger study of the reactivity and mobility of uranyl (U(VI)O22+) cations in subsurface environments containing natural organic matter (NOM) and hydrous ferric oxides, we have examined the effect of reference humic and fulvic substances on the sorption of uranyl on 2-line ferrihydrite (Fh), a common, naturally occurring nano-Fe(III)-hydroxide. Uranyl was reacted with Fh at pH 4.6 and 7.0 in the presence and absence of Elliott Soil Humic Acid (ESHA) (0-835 ppm) or Suwanee River Fulvic Acid (SRFA) (0-955 ppm). No evidence was found for reduction of uranyl by either form of NOM after 24 h of exposure. The following three size fractions were considered in this study: (1) ≥0.2 μm (Fh-NOM aggregates), (2) 0.02-0.2 μm (dispersed Fh nanoparticles and NOM macro-molecules), and (3) <0.02 μm (dissolved). The extent to which U(VI) is sorbed in aggregates or dispersed as colloids was assessed by comparing U, Fe, and NOM concentrations in these three size fractions. Partitioning of uranyl between Fh and NOM was determined in size fraction (1) using X-ray absorption spectroscopy (XAS). Uranyl sorption on Fh-NOM aggregates was affected by the presence of NOM in different ways depending on pH and type of NOM (ESHA vs. SRFA). The presence of ESHA in the uranyl-Fh-NOM ternary system at pH 4.6 enhanced uranyl uptake more than the presence of SRFA. In contrast, neither form of NOM affected uranyl sorption at pH 7.0 over most of the NOM concentration range examined (0-500 ppm); at the highest NOM concentrations (500-955 ppm) uranyl uptake in the aggregates was slightly inhibited at pH 7.0, which is interpreted as being due to the dispersion of Fh aggregates. XAS at the U LIII-edge was used to characterize molecular-level changes in uranyl complexation as a result of sorption to the Fh-NOM aggregates. In the absence of NOM, uranyl formed dominantly inner-sphere, mononuclear, bidentate sorption complexes on Fh. However, when NOM concentration was increased at pH 4.6, the

Uranyl ion recovery from waste waters by microbiological collectors

International Nuclear Information System (INIS)

Cecal, Alexandru; Palamaru, Iliana; Navrotescu, Tinca

1995-01-01

This study deals with the bioaccumulation of uranyl ions from radioactive effluents by Scenedesmus quadricauda alga. From the experimental data one can observe a greater retaining capacity of uranyl ions after four days of contact time. Filtered uranium and alga content was determined by the arsenazo III spectrophotometric method. The colored compound was determined by using wavelength λ=665 nm. (authors)

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.

Nephrotoxicity of uranyl acetate: effect on rat kidney brush border membrane vesicles

International Nuclear Information System (INIS)

Goldman, M.; Yaari, A.; Moran, A.; Doshnitzki, Z.; Cohen-Luria, R.

2006-01-01

Since the Gulf war exposure to depleted uranium, a known nephrotoxic agent, there is a renewed interest in the toxic effects of uranium in general and its mechanism of nephrotoxicity which is still largely unknown in particular. In order to investigate the mechanism responsible for uranium nephrotoxicity and the therapeutic effect of urine alkalization, we utilized rat renal brush border membrane vesicles (BBMV). Uranyl acetate (UA) caused a decrease in glucose transport in BBMV. The apparent K i of uranyl was 139±30 μg uranyl/mg protein of BBMV. Uranyl at 140 μg/mg protein of BBMV reduced the maximal capacity of the system to transport glucose [V max 2.2±0.2 and 0.96±0.16 nmol/mg protein for control and uranyl treated BBMV (P m (1.54±0.33 and 1.54±0.51 mM for control, and uranyl treated BBMV, respectively). This reduction in V max is at least partially due to a decrease in the number of sodium-coupled glucose transporters as apparent from the reduction in phlorizin binding to the uranyl treated membranes, V max was reduced from 247±13 pmol/mg protein in control BBMV to 119±3 pmol/mg protein in treated vesicles (P<0.001). The pH of the medium has a profound effect on the toxicity of UA on sodium-coupled glucose transport in BBMV: higher toxicity at neutral pH (around pH 7.0), and practically no toxicity at alkaline pH (7.6). This is the first report showing a direct inhibitory dose and pH dependent effect of uranyl on the glucose transport system in isolated apical membrane from kidney cortex. (orig.)

Interaction of Aluminum with PHFτ in Alzheimer’s Disease Neurofibrillary Degeneration Evidenced by Desferrioxamine-Assisted Chelating Autoclave Method

Science.gov (United States)

Murayama, Harunobu; Shin, Ryong-Woon; Higuchi, Jun; Shibuya, Satoshi; Muramoto, Tamaki; Kitamoto, Tetsuyuki

1999-01-01

To demonstrate that aluminum III (Al) interacts with PHFτ 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-τ antibodies, significantly enhanced the PHFτ immunoreactivity of the NFD. These results suggest that each of the phosphorylated epitopes in PHFτ are partially masked by Al binding. Incubation of AD sections with AlCl3 before Morin staining revealed Al accumulation with association to neurofibrillary tangles. Such incubation before immunostaining with the phosphorylation-dependent anti-τ 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 PHFτ. Al binding was further documented for electrophoretically-resolved PHFτ on immunoblots, indicating direct Al binding to PHFτ. In vitro aggregation by AlCl3 was observed for PHFτ but was lost on dephosphorylation of PHFτ. Taken together, phosphorylation-dependent and direct PHFτ-Al interaction occurs in the NFD of the AD brain. PMID:10487845

New insights into the acid mediated disproportionation of pentavalent uranyl

Energy Technology Data Exchange (ETDEWEB)

Mougel, Victor; Biswas, Biplab; Pecaut, Jacques; Mazzanti, Marinella [Laboratoire de Reconnaissance Ionique et Chimie de Coordination, SCIB, UMR-E 3 CEA-UJF FRE 3200 CNRS, INAC, CEA-Grenoble, 17 rue des Martyrs, 38054 Grenoble Cedex 09 (France)

2010-07-01

The reaction of benzoic acid with the uranyl(V) complex [(UO{sub 2}Py{sub 5})(KI{sub 2}Py{sub 2})] in pyridine leads to immediate disproportionation with formation of a hexa-nuclear U(IV) benzoate cluster, a bis-benzoate complex of uranyl(VI) and water. (authors)

Thermochemical investigations on uranyl phosphates and arsenates

International Nuclear Information System (INIS)

Barten, H.

1986-01-01

Results are described of a study of the thermochemical stability of anhydrous phosphates and arsenates. The results of phase studies deal with compound formation and characterization, coexisting phases and limiting physical or chemical properties. The uranyl phosphates evolve oxygen at higher temperatures and the arsenates lose arsenic oxide vapour. These phenomena give the possibility to describe their thermodynamic stabilities. Thus oxygen pressures of uranyl phosphates have been measured using a static, non-isothermal method. Having made available the pure anhydrous compounds in the course of this investigation, molar thermodynamic quantities have been measured as well. These include standard enthalpies of formation from solution calorimetry and high-temperature heat-capacity functions derived from enthalpy increments measured. Some attention is given to compounds with uranium in valencies lower than six which have been met during the investigation. An evaluation is made of the thermodynamics of the compounds studied, to result in tabulized high-temperature thermodynamic functions. Relative stabilities within the systems are discussed and comparisons of the uranyl phosphates and the arsenates are made. (Auth.)

The application of time-resolved luminescence spectroscopy to a remote uranyl sensor

International Nuclear Information System (INIS)

Varineau, P.T.; Duesing, R.; Wangen, L.E.

1991-01-01

Time resolved luminescence spectroscopy is an effective method for the determination of a wide range of uranyl concentrations in aqueous samples. We have applied this technique to the development of a remote sensing device using fiber optic cables coupled with a micro flow cell in order to probe for uranyl in aqueous samples. This sensor incorporates a Nafion membrane through which UO 2 2+ can diffuse in to a reaction/analysis chamber which holds phosphoric acid, a reagent which enhances the uranyl luminescence intensity and lifetime. With this device, anionic and fluorescing organic interferences could be eliminated, allowing for the determination of uranyl over a concentration range of 10 4 to 10 -9 M. 17 refs., 5 figs

Synthesis of uranyl ion imprinted polymer and its application in analysis

International Nuclear Information System (INIS)

Xiao Jingshui; Liu Huijun; Xiao Xilin; Huang Shengli

2011-01-01

Uranyl ion imprinted polymer beads were prepared by the copolymerization of styrene monomer and divinyl benzene as crosslinking agent in methanol solution,with the UO 2 2+ -o-dihydroxybenzene-4-vinyl pyridine ternary complex as template, the 2, 2'-azo-bis-isobutyronitrile as initiator and UO 2 2+ as the imprinting ion. The uranyl ions were removed from the polymer beads by treating with 6 mol/L HCl, leaving behind cavities that match uranyl ion in size. The treated polymer beads can preconcentrate uranyl ions from dilute aqueous solutions. The adsorption efficiency can reach 99% or above with good selectivity when pH is in the range of 5-7 and the adsorption time is more than 20 min. The elution rate can reach above 99% under the conditions of concentration of HCl being above 1.0 mol/L, elution time more than 20 min and the elution Janume more than 5 times the Janume of ion imprinted polymer. The uranyl ion imprinted polymer beads have been successfully applied to determine micro-uranium in brine samples. The results are satisfactory compared with NBS method.(authors)

Removal of uranyl ions from residual waters using some algae types

International Nuclear Information System (INIS)

Cecal, Al.; Rudic, V.; Gulea, A.; Palamaru, I.; Humelnicu, D.; Salaru, V.V.; Popa, K.

1997-01-01

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, Penicillium sp, as well as the Glucide extract of Porphyridium cruentum, in several experimental conditions. The retaining degree of the bioaccumulated uranyl ions, as well as the leaching degree, in HCl and H 2 O media, of the same ions previously retained on algae, were karakumica >Penicillium sp> Calothrix brevissima. The leaching effect of bioaccumulated uranyl ions is higher in hydrochloric acid then in water. (authors)

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.

Transfer of copper from a chelated 67Cu-antibody conjugate to ceruloplasmin in lymphoma patients

International Nuclear Information System (INIS)

Mirick, Gary R.; O'Donnell, Robert T.; DeNardo, Sally J.; Shen Sui; Meares, Claude F.; DeNardo, Gerald L.

1999-01-01

The Lym-1 monoclonal antibody was conjugated with the bifunctional chelating agent 6-[p-(bromoacetamido)benzyl]-1,4,8,11-tetraazacyclotetradecane-N,N',N'',N' -tetraacetic acid (BAT), using 2IT as a linker, and radiolabeled with 67 Cu to make the radiopharmaceutical, 67 Cu-2IT-BAT-Lym-1. Ten patients received a total of 18 doses of 67 Cu-2IT-BAT-Lym-1 as targeted, systemic radiotherapy. The beta phase of blood clearance, when corrected for 67 Cu decay, was positive or flat, a phenomenon not observed in similar patients treated with 131 I-Lym-1. The flat beta phase of blood clearance suggested recycling of 67 Cu from 67 Cu-2IT-BAT-Lym-1 to another plasma protein. Therefore, the amount of 67 Cu transferred from the radiopharmaceutical to CP, Alb, and TF was measured using affinity-purified polyclonal antibodies. The fraction of plasma 67 Cu precipitated by anti-human CP increased daily; most blood radioactivity was 67 Cu-CP after a median of 4 days (range 2-7 days). The transfer of 67 Cu to CP was observed in all patients and was consistent from dose to dose within the same patient. An average of 2.8±1.5% (range 0.8-7.8%) of the 67 Cu dose (%ID) was transferred to CP. The release rate of 67 Cu-CP from the liver into the blood was 0.9±0.4 %ID/day for the first 3 days. The 67 Cu-CP effective clearance half-life was 3.7 ± 0.7 days. Subtraction of the 67 Cu-CP activity from the total blood radioactivity yielded a biphasic blood clearance similar to that obtained for patients given 131 I-Lym-1. Cu-67-CP increased the AUC for whole blood by 24 ± 10%. The %ID of 67 Cu recycled correlated with GGT, ALT, and alkaline phosphatase levels; r=0.958 (p 67 Cu-2IT-BAT-Lym-1 and recycles a small fraction of the 67 Cu, transferring it to CP

The gas-phase bis-uranyl nitrate complex ((UO2)2(NO3)5)-: infrared spectrum and structure

International Nuclear Information System (INIS)

Groenewold, G.S.; van Stipdonk, Michael J.; Oomens, Jos; De Jong, Wibe A.; McIlwain, Michael E.

2011-01-01

The infrared spectrum of the bis-uranyl nitrate complex ((UO 2 ) 2 (NO 3 ) 5 ) - was measured in the gas phase using multiple photon dissociation (IRMPD). Intense absorptions corresponding to the nitrate symmetric and asymmetric vibrations, and the uranyl asymmetric vibration were observed. The nitrate v 3 vibrations indicate the presence of nitrate in a bridging configuration bound to both uranyl cations, and probably two distinct pendant nitrates in the complex. The coordination environment of the nitrate ligands and the uranyl cations were compared to those in the mono-uranyl complex. Overall, the uranyl cation is more loosely coordinated in the bis-uranyl complex ((UO 2 ) 2 (NO 3 ) 5 ) - compared to the mono-complex (UO 2 (NO 3 ) 3 ) - , as indicated by a higher O-U-O asymmetric stretching (v 3 ) frequency. However, the pendant nitrate ligands are more strongly bound in the bis-complex than they are in the mono-uranyl complex, as indicated by the v 3 frequencies of the pendant nitrate, which are split into nitrosyl and O-N-O vibrations as a result of bidentate coordination. These phenomena are consistent with lower electron density donation per uranyl by the nitrate bridging two uranyl centers compared to that of a pendant nitrate in the mono-uranyl complex. The lowest energy structure predicted by density functional theory (B3LYP functional) calculations was one in which the two uranyl molecules bridged by a single nitrate coordinated in a bis-bidentate fashion. Each uranyl molecule was coordinated by two pendant nitrate ligands. The corresponding vibrational spectrum was in excellent agreement with the IRMPD measurement, confirming the structural assignment.

The gas-phase bis-uranyl nitrate complex ((UO2)2(NO3)5)-: infrared spectrum and structure

International Nuclear Information System (INIS)

Groenewold, Gary S.; van Stipdonk, Michael J.; Oomens, Jos; de Jong, Wibe; McIlwain, Michael E.

2011-01-01

The infrared spectrum of the bis-uranyl nitrate complex ((UO 2 ) 2 (NO 3 ) 5 ) - was measured in the gas phase using multiple photon dissociation (IRMPD). Intense absorptions corresponding to the nitrate symmetric and asymmetric vibrations, and the uranyl asymmetric vibration were observed. The nitrate nu3 vibrations indicate the presence of nitrate in a bridging configuration bound to both uranyl cations, and probably two distinct pendant nitrates in the complex. The coordination environment of the nitrate ligands and the uranyl cations were compared to those in the mono-uranyl complex. Overall, the uranyl cation is more loosely coordinated in the bis-uranyl complex ((UO 2 ) 2 (NO 3 ) 5 ) - compared to the mono-complex (UO 2 (NO 3 ) 3 ) - , as indicated by a higher O-U-O asymmetric stretching (nu3) frequency. However, the pendant nitrate ligands are more strongly bound in the bis-complex than they are in the mono-uranyl complex, as indicated by the ν 3 frequencies of the pendant nitrate, which are split into nitrosyl and O-N-O vibrations as a result of bidentate coordination. These phenomena are consistent with lower electron density donation per uranyl by the nitrate bridging two uranyl centers compared to that of a pendant nitrate in the mono-uranyl complex. The structure was calculated using density functional theory (B3LYP functional), which produced a structure in which the two uranyl molecules bridged by a single nitrate coordinated in a bis-bidentate fashion. Each uranyl molecule was coordinated by two pendant nitrate ligands. The corresponding vibrational spectrum was in excellent agreement with the IRMPD measurement, confirming the structural assignment.

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

Optimized conditions for chelation of yttrium-90-DOTA immunoconjugates.

Science.gov (United States)

Kukis, D L; DeNardo, S J; DeNardo, G L; O'Donnell, R T; Meares, C F

1998-12-01

Radioimmunotherapy (RIT) with 90Y-labeled immunoconjugates has shown promise in clinical trials. The macrocyclic chelating agent 1,4,7,10-tetraazacyclododecane-N,N',N",N"'-tetraacetic acid (DOTA) binds 90Y with extraordinary stability, minimizing the toxicity of 90Y-DOTA immunoconjugates arising from loss of 90Y to bone. However, reported 90Y-DOTA immunoconjugate product yields have been typically only BAD) was conjugated to the monoclonal antibody Lym-1 via 2-iminothiolane (2IT). The immunoconjugate product, 2IT-BAD-Lym-1, was labeled in excess yttrium in various buffers over a range of concentrations and pH. Kinetic studies were performed in selected buffers to estimate radiolabeling reaction times under prospective radiopharmacy labeling conditions. The effect of temperature on reaction kinetics was examined. Optimal radiolabeling conditions were identified and used in eight radiolabeling experiments with 2IT-BAD-Lym-1 and a second immunoconjugate, DOTA-peptide-chimeric L6, with 248-492 MBq (6.7-13.3 mCi) of 90Y. Ammonium acetate buffer (0.5 M) was associated with the highest uptake of yttrium. On the basis of kinetic data, the time required to chelate 94% of 90Y (four half-times) under prospective radiopharmacy labeling conditions in 0.5 M ammonium acetate was 17-148 min at pH 6.5, but it was only 1-10 min at pH 7.5. Raising the reaction temperature from 25 degrees C to 37 degrees C markedly increased the chelation rate. Optimal radiolabeling conditions were identified as: 30-min reaction time, 0.5 M ammonium acetate buffer, pH 7-7.5 and 37 degrees C. In eight labeling experiments under optimal conditions, a mean product yield (+/- s.d.) of 91%+/-8% was achieved, comparable to iodination yields. The specific activity of final products was 74-130 MBq (2.0-3.5 mCi) of 90Y per mg of monoclonal antibody. The immunoreactivity of 90Y-labeled immunoconjugates was 100%+/-11%. The optimization of 90Y-DOTA chelation conditions represents an important advance in 90Y RIT

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.

Orientational order and dynamics of water in bulk and in aqueous solutions of uranyl ions

International Nuclear Information System (INIS)

Chopra, Manish; Choudhury, Niharendu

2014-01-01

Molecular dynamics simulations in canonical ensemble of aqueous solutions of uranyl nitrate and bulk water at ambient condition have been carried out to investigate orientational order and dynamics of water. The orientational distributions of water around a central water molecule in bulk water and around a uranyl ion in an aqueous uranyl solution have been calculated. Orientational dynamics of water in bulk and in aqueous uranyl nitrate solution have also been analysed. (author)

Contribution to the study of uranyl salts in butyl phosphate solutions; Contribution a l'etude des solutions de sels d'uranyle dans les phosphates butyliques

Energy Technology Data Exchange (ETDEWEB)

Coulon, A [Commissariat a l' Energie Atomique, Fontenay-aux-Roses (France). Centre d' Etudes Nucleaires

1965-06-01

A spectroscopic study in the normal infrared region and involving the following associations: tri-alkyl phosphates (tri-butyl, tri-ethyl, tri-methyl), uranyl salts (nitrate, chloride, acetate) has confirmed the existence of an interaction between the phosphoryl group and the uranium atom, as shown by a movement of absorption band for the valency P = 0 from {approx} 1270 cm{sup -1} to {approx} 1180 cm{sup -1}. A study of the preparation, analysis and spectroscopy of the solids obtained by the precipitation of uranyl salts by acid butyl phosphates has been carried out. By infrared spectrophotometry it has been shown that the tri-butyl and di-butyl phosphates are associated in non-polar diluents even before the uranium is introduced. The extraction of uranyl salts from acid aqueous solutions by a diluted mixture of tri-butyl and di-butyl phosphates proceeds by different mechanisms according to the nature of the ion (nitrate or chloride). (author) [French] Une etude spectroscopique dans l'infrarouge moyen portant sur les associations: - phosphates trialcoyliques (tributylique - triethylique - trimethylique) - sels d'uranyle (nitrate, chlorure, acetate) a confirme l'existence d'une interaction entre le groupement phosphoryle et l'atome d'uranium, se manifestant par un deplacement de la bande d'absorption de la vibration de valence P = 0 de {approx} 1270 cm{sup -1} a {approx} 1180 cm{sup -1}. Une etude preparative, analytique et spectroscopique des solides obtenus par precipitation de sels d'uranyle par les phosphates butyliques acides a ete effectuee. La spectrophotomerie infrarouge met en evidence l'association, anterieure a toute introduction d'uranium, des phosphates tributylique et dibutylique dans des diluants non polaires. L'extraction de sels d'uranyle, d'une solution aqueuse acide par un melange dilue de phosphates tributylique et dibutylique, s'effectue suivant des processus differents a la nature de l'anion (nitrate ou chlorure). (auteur)

Chemistry of the uranyl group

International Nuclear Information System (INIS)

Zarli, B.; Dall'olio, G.; Sindellari, L.

1976-01-01

Some uranyl complexes with hexamethylphosphoramide (HMPA) and urea were prepared and characterized. The compounds with the former ligand have the general formula UO 2 X 2 .HMPA (where X = (C 2 H 5 ) 2 NCSe 2 - , (C 2 H 5 ) 2 NCS 2 - or CH 3 COO - ). For the acetato derivatives a dimeric acetato-bridged structure is suggested. Some properties of UO 2 (NO 3 ) 2 .2(HMPA) are also described. With the latter ligand, in addition to the complexes UO 2 (NO 3 ) 2 .2urea and [UO 2 (urea) 4 (H 2 0)](NO 3 ) 2 already known, the novel complexes UO 2 (pycrate) 2 .4urea and [UO 2 (CH 3 COO) 2 .urea]sub(n) (where n is probably 2) have been prepared. All attempts to obtain urea complexes of uranyl diethyldithio- or diethyldiselenocarbamate failed and only adducts of unsatisfactory stoichiometry were isolated. (author)

Chemistry of the uranyl group. VI. Complexes of uranyl with hexamethylphosphoramide and urea

Energy Technology Data Exchange (ETDEWEB)

Zarli, B; Dall' olio, G; Sindellari, L [Consiglio Nazionale delle Ricerche, Padua (Italy). Lab. di Chimica e Tecnologia dei Radioelementi

1976-01-01

Some uranyl complexes with hexamethylphosphoramide (HMPA) and urea were prepared and characterized. The compounds with the former ligand have the general formula UO/sub 2/X/sub 2/.HMPA (where X = (C/sub 2/H/sub 5/)/sub 2/NCSe/sub 2//sup -/, (C/sub 2/H/sub 5/)/sub 2/NCS/sub 2//sup -/ or CH/sub 3/COO/sup -/). For the acetato derivatives a dimeric acetato-bridged structure is suggested. Some properties of UO/sub 2/(NO/sub 3/)/sub 2/.2(HMPA) are also described. With the latter ligand, in addition to the complexes UO/sub 2/(NO/sub 3/)/sub 2/.2urea and (UO/sub 2/(urea)/sub 4/(H/sub 2/0))(NO/sub 3/)/sub 2/ already known, the novel complexes UO/sub 2/(pycrate)/sub 2/.4urea and (UO/sub 2/(CH/sub 3/COO)/sub 2/.urea)sub(n) (where n is probably 2) have been prepared. All attempts to obtain urea complexes of uranyl diethyldithio- or diethyldiselenocarbamate failed and only adducts of unsatisfactory stoichiometry were isolated.

Unusual case of a polar copper(II) uranyl phosphonate that fluoresces

Energy Technology Data Exchange (ETDEWEB)

Nelson, A.G.D.; Albrecht-Schmitt, Th.E. [Department of Civil Engineering and Geological Sciences and Department of Chemistry and Biochemistry, 156 Fitzpatrick Hall, University of Notre Dame, Notre Dame, Indiana (United States)

2010-06-15

A polar Cu(II) uranyl diphosphonate, Cu(H{sub 2}O){sub 4}(UO{sub 2}){sub 3}(H{sub 2}O){sub 2}[CH{sub 2}(PO{sub 3}){sub 2}]{sub 2}.5H{sub 2}O, has been prepared under mild hydrothermal conditions. This compound has direct linkages between the oxo atoms of the uranyl moieties and the Cu(II) centers. Despite the presence of Cu(II) in the structure, vibronically-coupled emission is still observed, most likely because there are two crystallographically unique uranyl moieties, only one of which bonds to Cu(II). (authors)

Mass-spectrometric study of volatile uranyl β-diketonates and their adducts

International Nuclear Information System (INIS)

Adamov, V.M.; Belyaev, B.N.; Berezinskij, S.O.; Sidorenko, G.V.; Suglobov, D.N.

1985-01-01

The mass spectra of a number of uranyl β-diketonates containing methyl, trifluoromethyl and tert-butyl substituents in β-diketonate anion, and their adducts are measured. The form of the unsolvated β-diketonates and their adducts in gas phase is studied. The ways of fragmentation of uranyl β-diketonates and their adducts are investigated. The data concerning the thermal and chemical side reactions proceeding with uranyl β-diketonates and their addicts in an ion source are obtained. The mass spectra of the samples of neptunyl and plutonyl β-diketonate adducts synthesized for the first time are measured

Time-resolved luminescence studies in hydrogen uranyl phosphate intercalated with amines

Energy Technology Data Exchange (ETDEWEB)

Novo, Joao Batista Marques [Departamento de Quimica, Universidade Federal do Parana, CP 19081, 81531-990 Curitiba-PR (Brazil)]. E-mail: jbmnovo@quimica.ufpr.br; Batista, Fabio Roberto [Departamento de Quimica, Universidade Federal do Parana, CP 19081, 81531-990 Curitiba-PR (Brazil); Cunha, Carlos Jorge da [Departamento de Quimica, Universidade Federal do Parana, CP 19081, 81531-990 Curitiba-PR (Brazil); Dias, Lauro Camargo Jr. [Departamento de Quimica, Universidade Federal do Parana, CP 19081, 81531-990 Curitiba-PR (Brazil); Teixeira Pessine, Francisco Benedito [Instituto de Quimica, Universidade Estadual de Campinas, CP 6154, 13084-971 Campinas-SP (Brazil)

2007-05-15

Time-resolved luminescence decays of intercalated compounds of hydrogen uranyl phosphate (HUP) with p-toluidinium (HUPPT), benzylaminium (HUPBZ), {alpha}-methylbenzylaminium (HUPMBZ) and hydroxylaminium (HUPHAM) were studied. The prepared compounds belong to the tetragonal P4/ncc space group and showed 00 l reflections shifted to lower angles relative to HUP, indicating that the intercalation increases the c parameter of the unit cell. The luminescence decays of the compounds with 100% of intercalation ratio (HUPHAM and HUPBZ) were analyzed by Global Analysis, assuming Lianos' stretched exponential as the model function, which can be applied to compounds with restricted geometry and mobile donor and quencher molecules. It was remarkable that the luminescence decays showed that the quenching of the emission of the uranyl ions by the intercalated protonated amines is not restricted by low dimensionality of the host uranyl phosphate, and that a diffusion mechanism occurs. Benzylaminium cation efficiently quenches the excited energy of the uranyl ions at close distance, but the long-range and long-lifetime quenching is hindered. A different situation is found in the case of the small hydroxylaminium cation, where the long distance diffusion of the species is fast, playing an important role in the quenching of the excited uranyl ions at longer times.

Time-resolved luminescence studies in hydrogen uranyl phosphate intercalated with amines

International Nuclear Information System (INIS)

Novo, Joao Batista Marques; Batista, Fabio Roberto; Cunha, Carlos Jorge da; Dias, Lauro Camargo Jr.; Teixeira Pessine, Francisco Benedito

2007-01-01

Time-resolved luminescence decays of intercalated compounds of hydrogen uranyl phosphate (HUP) with p-toluidinium (HUPPT), benzylaminium (HUPBZ), α-methylbenzylaminium (HUPMBZ) and hydroxylaminium (HUPHAM) were studied. The prepared compounds belong to the tetragonal P4/ncc space group and showed 00 l reflections shifted to lower angles relative to HUP, indicating that the intercalation increases the c parameter of the unit cell. The luminescence decays of the compounds with 100% of intercalation ratio (HUPHAM and HUPBZ) were analyzed by Global Analysis, assuming Lianos' stretched exponential as the model function, which can be applied to compounds with restricted geometry and mobile donor and quencher molecules. It was remarkable that the luminescence decays showed that the quenching of the emission of the uranyl ions by the intercalated protonated amines is not restricted by low dimensionality of the host uranyl phosphate, and that a diffusion mechanism occurs. Benzylaminium cation efficiently quenches the excited energy of the uranyl ions at close distance, but the long-range and long-lifetime quenching is hindered. A different situation is found in the case of the small hydroxylaminium cation, where the long distance diffusion of the species is fast, playing an important role in the quenching of the excited uranyl ions at longer times

Synthesis and complexation properties towards uranyl cation of carboxylic acid derivatives of p-tert-butyl-calix[6]arene

International Nuclear Information System (INIS)

Souane, R.

2005-03-01

In the fuel reprocessing plants radioactive metals, and more particularly, uranium in UO 2 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 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 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 (ΔlogΒ110 = 4.3), and than the effect of the groupings nitro in para position has low influence on the complexation of UO 2 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. (author)

Spectroscopic characterization of alkaline earth uranyl carbonates

International Nuclear Information System (INIS)

Amayri, Samer; Reich, Tobias; Arnold, Thuro; Geipel, Gerhard; Bernhard, Gert

2005-01-01

A series of alkaline uranyl carbonates, M[UO 2 (CO 3 ) 3 ].nH 2 O (M=Mg 2 , Ca 2 , Sr 2 , Ba 2 , Na 2 Ca, and CaMg) was synthesized and characterized by inductively coupled plasma mass spectrometry (ICP-MS) and atomic absorption spectrometry (AAS) after nitric acid digestion, X-ray powder diffraction (XRD), and thermal analysis (TGA/DTA). The molecular structure of these compounds was characterized by extended X-ray absorption fine-structure (EXAFS) spectroscopy and X-ray photoelectron spectroscopy (XPS). Crystalline Ba 2 [UO 2 (CO 3 ) 3 ].6H 2 O was obtained for the first time. The EXAFS analysis showed that this compound consists of (UO 2 )(CO 3 ) 3 clusters similar to the other alkaline earth uranyl carbonates. The average U-Ba distance is 3.90+/-0.02A.Fluorescence wavelengths and life times were measured using time-resolved laser-induced fluorescence spectroscopy (TRLFS). The U-O bond distances determined by EXAFS, TRLFS, XPS, and Raman spectroscopy agree within the experimental uncertainties. The spectroscopic signatures observed could be useful for identifying uranyl carbonate species adsorbed on mineral surfaces

Influence of nitric acid on the kinetic of complexation of uranyl nitrate extracted by TBP

International Nuclear Information System (INIS)

Pushlenkov, M.F.; Zimenkov, V.V.

1982-02-01

The effect of nitric acid on the solvatation rate of uranyl nitrate with tributyl phosphate is studied. In the process of mass transfer, it is shown that nitric acid enables the extraction of uranyl nitrate, therefore its concentration in the organic phase exceeds that in equilibrium solution. Subsequently uranyl nitrate ''displaces'' nitric acid. The presence of the acid in aqueous and organic phases affects in a complicated manner the rate of solvatation of uranyl nitrate with tributyl phosphate [fr

Specific chelating reagent to extract uranium from the sea water

International Nuclear Information System (INIS)

Tabushi, Iwao; Kobuke, Yoshiaki

1982-01-01

The behavior of uranyl ions as seen from the chemistry of complex as the object of molecule recognition was examined on the basis of the research of structure and equilibrium in solution, in an attempt for the search of specific ligands and the molecular design of adsorbents. What is the most essential for the extraction of uranyl ions from sea water is the development of an excellent adsorbent with rapid adsorption, large equilibrium adsorption and high physical-chemical stability. Based on this appreciation, attempt has been made to find out the molecular design of an excellent adsorbent, starting with the chemistry of complex of uranyl ions. For the purpose, the following matters are reviewed: uranium in nature, the chemistry of complex of uranyl ions, specific ligands for the uranyl ions in sea water, the adsorbent resins for sea-water uranium, the proposals for an adsorbent system. (Mori, K.)

Potential New Ligand Systems for Binding Uranyl Ions in Seawater Environments

Energy Technology Data Exchange (ETDEWEB)

Arnold, John [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States)

2014-12-13

Work began this quarter on a new project involving a combined computational and biosynthetic approach to selective recognition of uranyl ion in aqueous solution. This project exploits the results of computational studies to discover new ligand classes. Synthetic studies will follow to generate target systems for uranyl binding and determination of binding constants. The process will be iterative, with results from computation informing synthesis, and vice versa. The theme of the ligand classes to be examined initially will be biologically based. New phosphonate-containing α-amino acid N-carboxyanhydride (NCA) monomers were used recently to prepare well-defined phosphonate-containing poly-peptides and block copolypeptides. Our first approach is to utilize these phosphate- and phosphonate-containing NCAs for the coordination of uranyl. The work includes the laboratory-scale preparation of a series of NCAs and the full thermodynamic and spectroscopic characterization of the resulting uranyl complexes. We are also evaluating the sequestering activity in different physiological and environmental conditions of these copolymers as well as their biodegradability.

Influence of Acidity on Uranyl Nitrate Association in Aqueous Solutions: A Molecular Dynamics Simulation Study

International Nuclear Information System (INIS)

de Almeida, Valmor F.; Cui, Shengting; Khomami, Bamin; Ye, Xianggui; Smith, Rodney Bryan

2010-01-01

Uranyl ion complexation with water and nitrate is a key aspect of the uranium/plutonium extraction process. We have carried out a molecular dynamics simulation study to investigate this complexation process, including the molecular composition of the various complex species, the corresponding structure, and the equilibrium distribution of the complexes. The observed structures of the complexes suggest that in aqueous solution, uranyls are generally hydrated by 5 water molecules in the equatorial plane. When associating with nitrate ions, a water molecule is replaced by a nitrate ion, preserving the five-fold coordination and planar symmetry. Analysis of the pair correlation function between uranyl and nitrate suggests that nitrates bind to uranyl in aqueous solution mainly in a monodentate mode, although a small portion of bidentates occur. Dynamic association and dissociation between uranyls and nitrates take place in aqueous solution with a substantial amount of fluctuation in the number of various uranyl nitrate species. The average number of the uranyl mononitrate complexes shows a dependence on acid concentration consistent with equilibrium-constant analysis, namely, the concentration of [UO2NO3]+ increases with nitric acid concentration.

Infrared studies on complexes between octaethyltetraamidepyrophosphate (OETAPP) and uranyl salts

International Nuclear Information System (INIS)

Grychowski, P.; Mikulski, J.; Moravets, Ya.; Shara, V.; Shourkova, L.

1981-01-01

Uranyl nitrate and uranyl chloride were extracted from the water phase with CHCl 3 solution of octaethyltetraamidepyrophosphate (OETAPP). Infrared spectra of the organic phases were recorded before and after the extraction. For both systems, the frequency of the P=O stretching mode of OETAPP after the extraction was lowered, which indicates for the formation of OETAPP UO 2 (NO 3 ) 2 and OETAPP UO 2 Cl 2 complexes. If uranyl nitrate was extracted with OETAPP in CCl 4 a precipitate was formed in the solution. From the analysis of the IR spectrum of the precipitate it was concluded that the complex OETAPP UO 2 (NO 3 ) 2 was formed also in this case, however, the complex was insoluble in CCl 4 . (author)

Radiometallating antibodies and autoantigenic peptides

International Nuclear Information System (INIS)

Mercer-Smith, J.A.; Lewis, D.; Cole, D.A.; Newmyer, S.L.; Schulte, L.D.; Mixon, P.L.; Schreyer, S.A.; Burns, T.P.; Roberts, J.C.; Figard, S.D.; McCormick, D.J.; Lennon, V.A.; Hayashi, M.; Lavallee, D.K.

1991-01-01

We have developed methods to radiolabel large molecules, using porphyrins as bifunctional chelating agents for radiometals. The porphyrins are substituted with an N- benzyl group to activate them for radiometallation under mild reaction conditions. Porphyrins that have one functional group for covalent attachment to other molecules cannot cause crosslinking. We have examined the labeling chemistry for antibodies and have developed methods to label smaller biologically active molecules, such as autoantigenic peptides (fragments of the acetylcholine receptor), which are pertinent to myasthenia gravis research. The methods of covalent attachment of these bifunctional chelating agents to large molecules, the radiometallation chemistry, and biological characterization of the radiolabeled compounds will be discussed

Volatile uranyl hexafluoroacetoacetonate complexes

International Nuclear Information System (INIS)

Dines, M.B.; Hall, R.B.; Kaldor, A.; Kramer, G.M.; Maas, E.T. Jr.

1980-01-01

A composition of matter is described, characterized by the formula UO 2 (CF 3 COCHCOCF 3 ).L where L is a ligand selected from isopropanol, ethanol, isobutanol, tert-butanol, methanol, tetrahydrofuran, acetone, dimethylformamide, n-propanol and ethyl acetate. A process for producing the complex comprises reacting uranyl chloride with a hexafluoroacetylacetonate dissolved in a ligand L: experimental details are given. (U.K.)

Removal of uranyl ions from residual waters using some algae types

International Nuclear Information System (INIS)

Cecal, A.; Palamaru, I.; Humelnicu, D.; Popa, K.; Salaru, V.V.; Rudic, V.; 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 Glucid extract of Porphyridium cruentum, under various experimental conditions. The retaining degree of the bioaccumulated uranyl ions, as well as the leaching degree, in HCl and H 2 O media, of the same ions previously retained on algae were established. The retaining degree decreases in the series: Scenedesmus quadricauda > Anabaena karakumica > Penicillinium sp > Calothrix brevissima. The leaching effect of bioaccumulated uranyl ions is higher in hydrochloric acid than in water. (author)

Cyanex based uranyl sensitive polymeric membrane electrodes.

Science.gov (United States)

Badr, Ibrahim H A; Zidan, W I; Akl, Z F

2014-01-01

Novel uranyl selective polymeric membrane electrodes were prepared using three different low-cost and commercially available Cyanex extractants namely, bis(2,4,4-trimethylpentyl) phosphinic acid [L1], bis(2,4,4-trimethylpentyl) monothiophosphinic acid [L2] and bis(2,4,4-trimethylpentyl) dithiophosphinic acid [L3]. Optimization and performance characteristics of the developed Cyanex based polymer membrane electrodes were determined. The influence of membrane composition (e.g., amount and type of ionic sites, as well as type of plasticizer) on potentiometric responses of the prepared membrane electrodes was studied. Optimized Cyanex-based membrane electrodes exhibited Nernstian responses for UO₂(2+) ion over wide concentration ranges with fast response times. The optimized membrane electrodes based on L1, L2 and L3 exhibited Nernstian responses towards uranyl ion with slopes of 29.4, 28.0 and 29.3 mV decade(-1), respectively. The optimized membrane electrodes based on L1-L3 showed detection limits of 8.3 × 10(-5), 3.0 × 10(-5) and 3.3 × 10(-6) mol L(-1), respectively. The selectivity studies showed that the optimized membrane electrodes exhibited high selectivity towards UO₂(2+) ion over large number of other cations. Membrane electrodes based on L3 exhibited superior potentiometric response characteristics compared to those based on L1 and L2 (e.g., widest linear range and lowest detection limit). The analytical utility of uranyl membrane electrodes formulated with Cyanex extractant L3 was demonstrated by the analysis of uranyl ion in different real samples for nuclear safeguards verification purposes. The results obtained using direct potentiometry and flow-injection methods were compared with those measured using the standard UV-visible and inductively coupled plasma spectroscopic methods. © 2013 Published by Elsevier B.V.

Chelating polymeric membranes

KAUST Repository

Peinemann, Klaus-Viktor; Villalobos Vazquez de la Parra, Luis Francisco; Hilke, Roland

2015-01-01

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.

Electron spectra and mechanism of complexing of uranyl nitrate in water-acetone solutions

International Nuclear Information System (INIS)

Zazhogin, A.A.; Zazhogin, A.P.; Komyak, A.I.; Serafimovich, A.I.

2003-01-01

Based on the analysis of the luminescence and electronic absorption spectra, the processes of complexing in an aqueous solution of UO 2 (NO 3 ) 2 ·6H 2 O with small additions of acetone have been studied. In a pure aqueous solution, uranyl exists as the complex UO 2 ·5H 2 O. It is shown that the addition of acetone to the solution leads to the displacement of some water molecules out of the first coordination sphere of uranyl and the formation of the uranyl nitrate dihydrate complexes UO 2 (NO 3 ) 2 ·2H 2 O. It has been established that the stability of these complexes is determined by the decrease in the water activity and in the degree of hydration of uranyl and nitrate, which is the result of the local increase in the concentration of acetone molecules (due to their hydrophobicity) in the regions of the solution where uranyl and nitrate ions are found. The experimental facts supported the mechanism proposed are presented. (authors)

A study of precipitation from pure solutions of uranyl nitrate

International Nuclear Information System (INIS)

Decrop, J.; Holder, J.; Sauteron, J.

1961-01-01

After its purification by extraction of the uranyl nitrate from the organic solvent, uranium has to be converted into solid form again: uranium trioxide (UO 3 ). It can be done either by thermal decomposition of uranyl nitrate or by precipitation of uranium, followed by filtration and calcination. Only the second method has been studied for now at the Bouchet plant. This paper reports the bench-scale and pilot-scale experiments of the studies of the precipitation of pure solutions of uranyl nitrate using ammonia (gaseous or in solution) or ammonium carbonate. These have been carried out at the Bouchet plant. It investigates the chemical aspect (pH, precipitates chemical composition) and the technical aspect of the different ways of precipitation (conditions of precipitation, decantation and filtration of precipitates). (M.P.)

Preparation of working calibration and test materials: uranyl nitrate solution

International Nuclear Information System (INIS)

Yamamura, S.S.; Spraktes, F.W.; Baldwin, J.M.; Hand, R.L.; Lash, R.P.

1977-05-01

Reliable working calibration and test materials (WCTMs) are essential to a meaningful analytical measurements quality assurance program. This report describes recommended methods for the preparation of uranyl nitrate solution WCTMs for testing analytical methods, for calibrating methods, and for testing personnel. Uranyl nitrate solution WCTMs can be synthesized from characterized starting materials or prepared from typical plant materials by thorough characterization with reference to primary or secondary reference calibration and test materials (PRCTMs or SRCTMs). Recommended starting materials are described along with detailed procedures for (a) preparing several widely-used types of uranyl nitrate solution WCTMs, (b) packaging the WCTMs, (c) analyzing the WCTMs to establish the reference values or to confirm the synthesis, and (d) statistically evaluating the analytical data to assign reference values and to assess the accuracy of the WCTMs

New chemistry of the uranyl ion in non aqueous media

International Nuclear Information System (INIS)

Siffredi, G.

2008-12-01

This work deals with new aspects of the chemistry of the uranyl(VI) ion {UO 2 } 2+ in anhydrous polar organic solvents such as the activation of the reputedly inert U-O yl bond and the controlled reduction of this species which represent a particularly active field of research that attracts much attention for both its fundamental aspects and applications. Treatment of uranyl(VI) compounds UO 2 X' 2 (X' = I, OTf, Cl) with Me 3 SiX (X = Cl, Br, I) reagents, in various anhydrous polar organic solvents, has been first considered. In most cases, reduction into tetravalent species with complete de-oxygenation of the uranyl {UO 2 } 2+ ion is observed. The reaction is particularly efficient in acetonitrile where the tetravalent [UX 4 (MeCN) 4 ] complexes, which are useful precursors in uranium chemistry, are isolated. In the course of these reactions, the influence of the solvent, the nature of X' and X in the UO 2 X' 2 precursor and the Me 3 SiX reagent are pointed out. Reaction of the uranyl(VI) UO 2 X 2 (X = I, Cl, OTf, NO 3 ) precursors with the anionic MC 5 R 5 (M = K, R = H, Me; M= Li, R = Me; M= Tl, R = H) reagents did not lead to the organometallic [(η 5 -C 5 R 5 ) n UO 2 X 2-n ] species (n = 1, 2) but to pentavalent uranyl(V) complexes. This method is a facile and rapid route towards the formation of stable pentavalent uranyl which offers promising sources for further U(V) chemical developments and for fundamental and applied interests. Their structure is strongly dependent on the nature of the solvent, the additional ligands X and of the M + cation. In pyridine, the {UO 2 (py) 5 } + ion appears to be an ubiquitous and a quite stable entity. The coordinating properties of the basic oxo groups, which coordinate easily to M + ions (M= Li, K, Tl), favour structural diversity with formation of hetero-polymetallic complexes such as [{UO 2 (py) 5 }{MX(py) 2 }] (M= Li, X I), [{UO 2 (py) 5 }{MX 2 (py) 2 }] ∞ (M= K, Tl, X= OTf; M= K, X= I), [{UO 2 (py) 5 }(M 2 X 3 )]�

Surface complexation modeling of uranyl adsorption on corrensite from the Waste Isolation Pilot Plant Site

Energy Technology Data Exchange (ETDEWEB)

Park, Sang-Won; Leckie, J.O. [Stanford Univ., CA (United States); Siegel, M.D. [Sandia National Labs., Albuquerque, NM (United States)

1995-09-01

Corrensite is the dominant clay mineral in the Culebra Dolomite at the Waste Isolation Pilot Plant. The surface characteristics of corrensite, a mixed chlorite/smectite clay mineral, have been studied. Zeta potential measurements and titration experiments suggest that the corrensite surface contains a mixture of permanent charge sites on the basal plane and SiOH and AlOH sites with a net pH-dependent charge at the edge of the clay platelets. Triple-layer model parameters were determined by the double extrapolation technique for use in chemical speciation calculations of adsorption reactions using the computer program HYDRAQL. Batch adsorption studies showed that corrensite is an effective adsorbent for uranyl. The pH-dependent adsorption behavior indicates that adsorption occurs at the edge sites. Adsorption studies were also conducted in the presence of competing cations and complexing ligands. The cations did not affect uranyl adsorption in the range studied. This observation lends support to the hypothesis that uranyl adsorption occurs at the edge sites. Uranyl adsorption was significantly hindered by carbonate. It is proposed that the formation of carbonate uranyl complexes inhibits uranyl adsorption and that only the carbonate-free species adsorb to the corrensite surface. The presence of the organic complexing agents EDTA and oxine also inhibits uranyl sorption.

Surface complexation modeling of uranyl adsorption on corrensite from the Waste Isolation Pilot Plant Site

International Nuclear Information System (INIS)

Park, Sang-Won; Leckie, J.O.; Siegel, M.D.

1995-09-01

Corrensite is the dominant clay mineral in the Culebra Dolomite at the Waste Isolation Pilot Plant. The surface characteristics of corrensite, a mixed chlorite/smectite clay mineral, have been studied. Zeta potential measurements and titration experiments suggest that the corrensite surface contains a mixture of permanent charge sites on the basal plane and SiOH and AlOH sites with a net pH-dependent charge at the edge of the clay platelets. Triple-layer model parameters were determined by the double extrapolation technique for use in chemical speciation calculations of adsorption reactions using the computer program HYDRAQL. Batch adsorption studies showed that corrensite is an effective adsorbent for uranyl. The pH-dependent adsorption behavior indicates that adsorption occurs at the edge sites. Adsorption studies were also conducted in the presence of competing cations and complexing ligands. The cations did not affect uranyl adsorption in the range studied. This observation lends support to the hypothesis that uranyl adsorption occurs at the edge sites. Uranyl adsorption was significantly hindered by carbonate. It is proposed that the formation of carbonate uranyl complexes inhibits uranyl adsorption and that only the carbonate-free species adsorb to the corrensite surface. The presence of the organic complexing agents EDTA and oxine also inhibits uranyl sorption

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.

Magnetic biosorbent for removal of uranyl ions

International Nuclear Information System (INIS)

Yamamura, Amanda P.G.; Yamaura, Mitiko; Costa, Caroline H.

2009-01-01

In this work magnetic biosorbent, which consisted of sugarcane bagasse as polymeric matrix with magnetite nanoparticles, was prepared. This magnetic composite has the purpose to remove uranyl ions from aqueous effluents. The magnetite was synthetized by simultaneous precipitation by addition a solution of NaOH to the aqueous solution containing Fe2+ and Fe3+. This magnetic bagasse biosorbent have presented superparamagnetic properties, that is, it have showed a high magnetization of saturation without hysteresis. The magnetic biosorbent was utilized to remove uranyl ions from water. Radioactive uranium waste is generated in hospitals, universities and it is used as fuel for nuclear power plants. Variables of adsorption process of uranyl ions by magnetic biosorbent in nitric solutions were investigated, such as, time required for the uranium-magnetic bagasse biosorbent equilibrium in the interval from 20 to 90 min, pH in the intervals from 2 to 5 and 10, stirring speed from 240 to 500 r.p.m. and biosorbent dose from 2 to 25 g.L-1 were investigated. Equilibrium isotherm was verified according to the Langmuir and Freundlich adsorption isotherm models. The highest adsorption capacity reached 17 mg.g-1. The Gibbs free energy indicated to be spontaneous adsorption. This work updates the paper was presented on the 2007 INAC.

DNA conformational analysis in solution by uranyl mediated photocleavage

DEFF Research Database (Denmark)

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

1990-01-01

Uranyl mediated photocleavage of double stranded DNA is proposed as a general probing for DNA helix conformation in terms of minor groove width/electronegative potential. Specifically, it is found that A/T-tracts known to constitute strong distamycin binding sites are preferentially photocleaved ......, uranyl photocleavage of the internal control region (ICR) of the 5S-RNA gene yields a cleavage modulation pattern fully compatible with that obtained by DNase I which also--in a more complex way--senses DNA minor groove width....

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

International Nuclear Information System (INIS)

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

2005-01-01

The enthalpies of formation of seven uranyl oxide hydrate phases and one uranate have been determined using high-temperature oxide melt solution calorimetry: [(UO 2 ) 4 O(OH) 6 ](H 2 O) 5 , metaschoepite; β-UO 2 (OH) 2 ; CaUO 4 ; Ca(UO 2 ) 6 O 4 (OH) 6 (H 2 O) 8 , becquerelite; Ca(UO 2 ) 4 O 3 (OH) 4 (H 2 O) 2 ; Na(UO 2 )O(OH), clarkeite; Na 2 (UO 2 ) 6 O 4 (OH) 6 (H 2 O) 7 , the sodium analogue of compreignacite and Pb 3 (UO 2 ) 8 O 8 (OH) 6 (H 2 O) 2 , curite. The enthalpy of formation from the binary oxides, ΔH f-ox , at 298 K was calculated for each compound from the respective drop solution enthalpy, ΔH ds . The standard enthalpies of formation from the elements, ΔH f 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 -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

Molecular approach of uranyl/mineral surfaces: theoretical approach

International Nuclear Information System (INIS)

Roques, J.

2009-01-01

As migration of radio-toxic elements through the geosphere is one of the processes which may affect the safety of a radioactive waste storage site, the author shows that numerical modelling is a support to experimental result exploitation, and allows the development of new interpretation and prediction codes. He shows that molecular modelling can be used to study processes of interaction between an actinide ion (notably a uranyl ion) and a mineral surface (a TiO 2 substrate). He also reports the predictive theoretical study of the interaction between an uranyl ion and a gibbsite substrate

Uranyl peroxide enhanced nuclear fuel corrosion in seawater.

Science.gov (United States)

Armstrong, Christopher R; Nyman, May; Shvareva, Tatiana; Sigmon, Ginger E; Burns, Peter C; Navrotsky, Alexandra

2012-02-07

The Fukushima-Daiichi nuclear accident brought together compromised irradiated fuel and large amounts of seawater in a high radiation field. Based on newly acquired thermochemical data for a series of uranyl peroxide compounds containing charge-balancing alkali cations, here we show that nanoscale cage clusters containing as many as 60 uranyl ions, bonded through peroxide and hydroxide bridges, are likely to form in solution or as precipitates under such conditions. These species will enhance the corrosion of the damaged fuel and, being thermodynamically stable and kinetically persistent in the absence of peroxide, they can potentially transport uranium over long distances.

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.

Influence of uranyl dibutylphosphate on the UV/VIS spectrophotometric online monitoring of uranium in tributylphosphate/hydrocarbon solvent

International Nuclear Information System (INIS)

Creech, E.T.; Rutenberg, A.C.; Smithwick, R.W.; Seals, R.D.

1984-01-01

In the uranium recovery process at the Y-12 Plant uranium is recovered from aqueous uranyl solutions by extraction into a solvent consisting of 30% tributylphosphate (TBP) and 70% hydrocarbon solvent. Within this process the uranium is continuously monitored by a UV/VIS absorbance measurement of the uranyl/tributylphosphate complex in the organic phase. The uranium is then further extracted from the organic phase to a final water phase. Dibutylphosphate (DBP), which is a decomposition product of TBP, builds up in the organic solvent. A very strong complex of uranyl/dibutylphosphate is formed which cannot be extracted into the aqueous phase. Prior to this work the uranyl/dibutylphosphate complex absorbance was assumed to be the same as the uranyl tributylphosphate complex. To determine the effect of the presence of uranyl/dibutylphosphate on the continuous UV/VIS monitor required (a) the purification of commercial dibutylphosphate, (b) the synthesis, and (c) the characterization of uranyl/dibutylphosphate

Separation of uranyl ion using polyaniline

International Nuclear Information System (INIS)

Jayshree Ramkumar; Chandramouleeswaran, S.

2013-01-01

Polyaniline (Pani) was synthesized by the chemical oxidation of aniline. The use of persulphate instead of dichromate was desired in order to avoid the incorporation of chromium in the polymer matrix. The presence of chromium in the matrix, when dichromate was used as an oxidant, was confirmed by various techniques. The batch mode experiments showed that Pani could be used for separation of different metal ions. These ions were converted into their anionic complexes using suitable complexing agents. It was found that EDTA was used as a suitable reagent for the separation of Cu 2+ from Zn 2+ whereas the uranyl ion uptake could be increased to about 95 % when carbonate was used instead of EDTA as complexing agent. A possible application of the above exchange system to preconcentration of uranyl ion from seawater has also been examined. (author)

Spectroscopic studies of 2-thenoyltrifluoro acetonate of uranyl salts doped with europium

International Nuclear Information System (INIS)

Nakagawa, F.T.; Luiz, J.E.M. de Sa; Felinto, M.C.F.C.; Brito, H.F.; Teotonio, E.E.S.

2006-01-01

Uranyl compounds present a great potential as luminescence materials. Some examples of applications are: in laser technology, cathode ray tube, X-rays diagnostic. In this work it was studied the synthesis, characterization and spectroscopic properties study of uranyl 2-thenoyl trifluoroacetonate and uranyl 2- thenoyl trifluoroacetonate doped with europium. The compounds were synthesized and characterized by infrared absorption spectroscopy, thermal analysis, scanning electronic microscopy, and electronic spectroscopy of emission and excitation. The Eu 3+ ion acted as an effective luminescent probe, however the process of energy transfer from UO 2 2+ to Eu 3+ ion has not been efficient. (author)

Radiolysis studies of uranyl nitrate solution in nitric acid medium

International Nuclear Information System (INIS)

Siri, Sandra; Mondino, Angel V.

2005-01-01

The radiolysis of acidic uranyl nitrate solutions was investigated using Co-60 gamma radiation. Hydrogen peroxide was determined as a function of increasing dose. The UV-vis absorption spectra of the irradiated solutions were measured and the spectral changes were analyzed. The increasing dose increases the absorbance intensities, possibly by an increment in nitrate concentration produced by radiolysis, which can originate the formation of different uranyl complexes in solution. (author)

Decomposition of uranyl peroxo-carbonato complex ion in the presence of metal oxides in carbonate media

International Nuclear Information System (INIS)

Dong-Yong Chung; Min-Sung Park; Keun-Young Lee; Eil-Hee Lee; Kwang-Wook Kim; Jei-Kwon Moon

2015-01-01

Uranium oxide was dissolved in the form of the uranyl peroxo-carbonato complex ion, UO 2 (O 2 )(CO 3 ) 2 4- in carbonate solutions with hydrogen peroxide. When UO 2 (O 2 )(CO 3 ) 2 4- ions lose their peroxide component, they become a stable species of uranyl tricarbonato complex ion, UO 2 (O 2 )(CO 3 ) 2 4- . The uranyl peroxo-carbonato complex self-decomposed more rapidly into the uranyl tricarbonato complex ion in the presence of a metal oxide in the carbonate solution. In this study, decomposition of the uranyl peroxo-carbonato complex in a carbonate solution was investigated in the presence of several metal oxides using absorption spectroscopy. (author)

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)

Sorption rate of uranyl ions by hyphan cellulose exchangers and by hydrated titanium dioxide

International Nuclear Information System (INIS)

Ambe, F.; Burba, P.; Lieser, K.H.

1979-01-01

Sorption of uranyl ions by the cellulose exchanger Hyphan proceeds rather fast. Two steps are observed with half-times of the order of 10 s and 2 min. The majority of the uranyl ions is bound in 1 min. Sorption of uranyl ions by titanium dioxide is a very slow process. For particle sizes between 0,1 and 0,5 mm the half-time is about 3 h and equilibrium is attained in about 1 day. The effect of stirring suspensions of inorganic sorbents like titanium dioxide in solution is investigated in detail. Sorption of uranyl ions by titanium dioxide and change in pH in solution are measured simultaneously as a function of time. (orig.) [de

Uranium (VI) chemistry at the interface solution/minerals (quartz and aluminium hydroxide): experiments and spectroscopic investigations of the uranyl surface species

International Nuclear Information System (INIS)

Froideval, A.

2004-09-01

This study deals with the understanding of the uranyl chemistry at the 0.1 M NaNO 3 solution/mineral (quartz and aluminium hydroxide) interface. The aims are:(i) to identify and to characterize the different uranyl surface species (mononuclear, polynuclear complexes and/or precipitates...), i.e. the coordination environments of sorbed/precipitated uranyl ions, by using X-ray photoelectron spectroscopy (XPS), extended X-ray absorption fine structure (EXAFS) and time-resolved laser-induced fluorescence spectroscopy (TRLFS), and;(ii) to investigate the influence of pH, initial uranyl aqueous concentration and hydroxyl ligand concentration on the uranyl surface speciation. Our study on the speciation of uranyl ions at the quartz surface (i) confirms the formation of uranyl polynuclear/oligomers on quartz from moderate (1 μmol/m 2 ) to high (26 μmol/m 2 ) uranyl surface concentrations and (ii) show that theses polynuclear species coexist with uranyl mononuclear surface species over a pH range ≅ 5-8.5 and a wide range of initial uranyl concentration o f the solutions (10-100 μM). The uranyl concentration of these surface species depends on pH and on the initial uranyl aqueous concentration. Hydrate (surface-) precipitates and/or adsorbed polynuclear species and monomeric uranyl surface complexes are formed on aluminium hydroxide. Uranyl mononuclear complexes are predominant at acidic pH, as well as uranyl in solution or on the surface. Besides mononuclear species, precipitates and/or adsorbed polynuclear species are predominantly formed at neutral pH values on aluminium hydroxide. A main contribution of our investigations is that precipitation and/or adsorption of polynuclear species seem to occur at low uranyl surface concentrations (0.01-0.4 μmol/m 2 ). The uranyl surface speciation is mainly dependent on the pH and the aluminol ligand concentration. (author)

Time-resolved luminescence spectroscopy of trace uranyl in wet sand

International Nuclear Information System (INIS)

Freed, D.

1993-01-01

The objective of the project was to develop a technique to observe and characterize the behaviour of uranium in unsaturated groundwater flow systems, particularly with regard to unstable ''fingered'' flow, which could drastically reduce time of travel. The actual experimental work described was a study of the feasibility of detecting uranyl at the parts-per-billion level in aqueous solution by means of its luminescence spectrum. A high-power UV laser was used to excite aqueous uranyl in a wet sand mixture; the characteristic green phosphorescence emitted in the decay transition was detected by a photomultiplier tube; and the amplified signal was sent to an oscilloscope in communication with Macintosh data acquisition software. At the time of the conference, a more sophisticated sample configuration for imaging the flow of uranyl was already under development. 5 refs., 3 figs

Time-resolved luminescence spectroscopy of trace uranyl in wet sand

Energy Technology Data Exchange (ETDEWEB)

Freed, D [Massachusetts Inst. of Tech., Cambridge, MA (United States)

1994-12-31

The objective of the project was to develop a technique to observe and characterize the behaviour of uranium in unsaturated groundwater flow systems, particularly with regard to unstable ``fingered`` flow, which could drastically reduce time of travel. The actual experimental work described was a study of the feasibility of detecting uranyl at the parts-per-billion level in aqueous solution by means of its luminescence spectrum. A high-power UV laser was used to excite aqueous uranyl in a wet sand mixture; the characteristic green phosphorescence emitted in the decay transition was detected by a photomultiplier tube; and the amplified signal was sent to an oscilloscope in communication with Macintosh data acquisition software. At the time of the conference, a more sophisticated sample configuration for imaging the flow of uranyl was already under development. 5 refs., 3 figs.

1H chemically induced dynamic nuclear polarization in the photodecomposition of uranyl carboxylates

International Nuclear Information System (INIS)

Rykov, S.V.; Khudyakov, I.V.; Skakovsky, E.D.; Burrows, H.D.; Formosinho, S.J.; Miguel, M. da G.M.

1991-01-01

Chemically induced dynamic nuclear polarization ( 1 H CIDNP) has been observed during photolysis of uranyl salts of pivalic, propionic, and acetic acids in D 2 O solution, [ 2 H 6 ]acetone, [ 2 H 4 ]methanol, or in some other solvent. The multiplet polarization of isobutene and isobutane protons has been found under photolysis of deoxygenated pivalate solution. The polarized compounds are formed in the triplet pairs of tert-butyl free radicals. 1 H Emission of the tert-butylperoxyl group and emission of 1 H from isobutene have been recorded under photolysis of air-saturated pivalate solutions. The CIDNP of butane protons stays as a multiplet. Such changes in the presence of air/oxygen have arisen apparently because of the formation of tert-butylperoxyl free radical and its reaction with tert-butyl radical products, i.e. hydroperoxide (peroxide) and isobutene. Isobutene probably forms a complex with molecular oxygen which has a very short proton relaxation time. During the photolysis of uranyl pivalate in the presence of p-benzoquinone (5 x 10 -2 -0.1 mol dm -3 ) we have not observed any CIDNP, whereas under p-benzoquinone concentrations of 10 -3 -10 -2 mol dm -3 the CIDNP from both hydroquinone and p-benzoquinone has been followed. Photolysis of uranyl propionate has led to CIDNP from butane protons. An emission from methyl group protons of a compound with an ethylperoxyl fragment in the presence of air/oxygen has been observed. The same polarization picture has arisen under interaction of photoexcited uranyl with propionic acid. During the photolysis of uranyl acetate at relatively low concentrations (10 -2 mol dm -3 ) a CIDNP very similar to that registered for uranyl propionate was recorded. The ethyl fragment is probably obtained in reactions for two methyl radicals formed from acetate with the parent uranyl acetate, namely hydrogen-atom abstraction and addition reactions. (author)

Thermodynamics of dehydration process of uranyl nitrate pentahydrate of thorium

International Nuclear Information System (INIS)

Khamidov, F.A.; Mirsaidov, I.U.; Nazarov, K.M.; Nasriddinov, S.K.; Badalov, A.B.

2010-01-01

Present article is devoted to thermodynamics of dehydration process of uranyl nitrate pentahydrate of thorium. The results of researches of dehydration process of uranyl nitrate pentahydrate of thorium Th(NO_3)_4·5H_2O were considered. The researches were carried out by means of tensimeter method with membrane zero-manometer under equilibrium conditions and at 300-450 K temperature ranges. The thermodynamic characteristics of dehydration process of initial crystalline hydrate was defined.

A surface structural model for ferrihydrite II: Adsorption of uranyl and carbonate

NARCIS (Netherlands)

Hiemstra, T.; Riemsdijk, van W.H.; Rossberg, A.; Ulrich, K.

2009-01-01

The adsorption of uranyl (UO22+) on ferrihydrite has been evaluated with the charge distribution (CD) model for systems covering a very large range of conditions, i.e. pH, ionic strength, CO2 pressure, U(VI) concentration, and loading. Modeling suggests that uranyl forms bidentate inner sphere

Electrochemical behavior of uranyl in anhydrous polar organic media

Energy Technology Data Exchange (ETDEWEB)

Burn, Adam G.; Nash, Kenneth L. [Washington State Univ., Pullmann, WA (United States). Dept. of Chemistry

2017-09-01

Weak complexes between pentavalent and hexavalent actinyl cations have been reported to exist in acidic, non-complexing high ionic strength aqueous media. Such ''cation-cation complexes'' were first identified in the context of actinide-actinide redox reactions in acidic aqueous media relevant to solvent extraction-based separation systems, hence their characterization is of potential interest for advanced nuclear fuel reprocessing. This chemistry could be relevant to efforts to develop advanced actinide separations based on the upper oxidation states of americium, which are of current interest. In the present study, the chemical behavior of pentavalent uranyl was examined in non-aqueous, aprotic polar organic solvents (propylene carbonate and acetonitrile) to determine whether UO{sub 2}{sup +} cations generated at the reducing working electrode surface would interact with the UO{sub 2}{sup 2+} cations in the bulk phase to form cation-cation complexes in such media. In magnesium perchlorate media, the electrolyte adsorbed onto the working electrode surface and interfered with the uranyl reduction/diffusion process through an ECE (electron transfer/chemical reaction/electron transfer) mechanism. In parallel studies of uranyl redox behavior in tetrabutylammonium hexafluorophosphate solutions, an EC (electron transfer/chemical reaction) mechanism was observed in the cyclic voltammograms. Ultimately, no conclusive electrochemical evidence demonstrated uranyl cation-cation interactions in the non-aqueous, aprotic polar organic solvent solutions, though the results reported do not completely rule out the presence of UO{sub 2}{sup +}.UO{sub 2}{sup 2+} complexes.

Role of N-Donor Sterics on the Coordination Environment and Dimensionality of Uranyl Thiophenedicarboxylate Coordination Polymers

Energy Technology Data Exchange (ETDEWEB)

Thangavelu, Sonia G. [Department; Butcher, Ray J. [Department; Cahill, Christopher L. [Department

2015-06-09

Thiophene 2,5-dicarboxylic acid (TDC) was reacted with uranyl acetate dihydrate and one (or none) of six N-donor chelating ligands (2,2'-bipyridine (BPY), 4,4'-dimethyl-2,2'-bipyridine (4-MeBPY), 5,5'-dimethyl-2,2'-bipyridine (5-MeBPY), 6,6'-dimethyl-2,2'-bipyridine (6-MeBPY), 4,4',6,6'-tetramethyl-2,2'-bipyridine (4,6-MeBPY), and tetrakis(2-pyridyl)pyrazine (TPPZ) to result in the crystallization of seven uranyl coordination polymers, which were characterized by their crystal structures and luminescence properties. The seven coordination polymers, Na2[(UO2)2(C6H2O4S)3]·4H2O (1), [(UO2)4(C6H2O4S)5(C10H8N2)2]·C10H10N2·3H2O (2), [(UO2)(C6H2O4S)(C12H12N3)] (3), [(UO2)(C6H2O4S)(C12H12N3)]·H2O (4), [(UO2)2(C6H2O4S)3]·(C12H14N2)·5H2O (5), [(UO2)3(CH3CO2)(C6H2O4S)4](C14H17N2)3·(C14H16N2)·H2O (6), and [(UO2)2(C6H2O4S)3](C24H18N6) (7), consist of either uranyl hexagonal bipyramidal or pentagonal bipyramidal coordination geometries. In all structures, structural variations in the local and global structures of 1–7 are influenced by the positions (or number) of methyl groups or pyridyl rings on the N-donor species, thus resulting in a wide diversity of structures ranging from single chains, double chains, or 2-D sheets. Direct coordination of N-donor ligands to uranyl centers is observed in the chain structures of 2–4 using BPY, 4-MeBPY, and 5-MeBPY, whereas the N-donor species participate as guests (as either neutral or charge balancing species) in the chain and sheet structures of 5–7 using 6-MeBPY, 4,6-MeBPY, and TPPZ, respectively. Compound 1 is the only structure that does not contain any N-donor ligands and thus crystallizes as a 2-D interpenetrating sheet. The luminescent properties of 1–7 are influenced by the direct coordination or noncoordination of N-donor species to uranyl centers. Compounds 2–4 exhibit typical UO22+ emission upon direct coordination of N-donors, but its absence is observed in 1

Radiometallating antibodies and biologically active peptides

International Nuclear Information System (INIS)

Mercer-Smith, J.A.; Roberts, J.C.; Lewis, D.; Newmyer, S.L.; Schulte, L.D.; Burns, T.P.; Mixon, P.L.; Jeffery, A.L.; Schreyer, S.A.; Cole, D.A.; Figard, S.D.; Lennon, V.A.; Hayashi, M.; Lavallee, D.K.

1990-01-01

We have developed methods to radiolabel large molecules, using porphyrins as bifunctional chelating agents for radiometals. The porphyrins are substituted with an N-benzyl group to activate them for radiometallation under mild reaction conditions. Porphyrins that have on functional group for covalent attachment to other molecules cannot cause crosslinking. We have examined the labeling chemistry for antibodies, and we have also developed methods to label smaller biologically active molecules, such as autoantigenic peptides. The autoantigenic peptides, fragments of the acetylcholine receptor, are under investigation for myasthenia gravis research. The methods of covalent attachment of these bifunctional chelating agents to large molecules and the radiometallation chemistry will be discussed

Tumor imaging with monoclonal antibodies

International Nuclear Information System (INIS)

Haisma, H.; Hilgers, J.

1987-01-01

Many monoclonal antibodies directed against tumor-associated antigens have been identified, but so far none of these are tumor specific. Polyclonal and monoclonal antibodies have been used for imaging of a wide variety of tumors with success. Radiolabeling of antibody is usually done with iodine isotopes of which 123 I is the best candidate for radioimmunodetection purposes. The labeling of antibodies through chelates makes it possible to use metal radioisotopes like 111 In, which is the best radioisotope for imaging with monoclonal antibodies due to its favorable half-life of 2.5 days. Usually imaging cannot be performed within 24 h after injection, but clearance of antibody can be increased by using F(ab) 2 of Fab. Another approach is to clear non-bound antibody by a second antibody, directed against the first. The detection limit of immunoimaging is about 2 cm, but will be improved by tomography or SPECT. There is still a high false positive and false negative rate, which makes it impossible to use radioimmunodetection as the only technique for diagnosis of tumors. In combination with other detection techniques, tumor imaging with monoclonal antibodies can improve diagnosis. 44 refs.; 3 tabs

Critical experiment study on uranyl nitrate solution experiment facility

International Nuclear Information System (INIS)

Zhu Qingfu; Shi Yongqian; Wang Jinrong

2005-01-01

The Uranyl Nitrate Solution Experiment Facility was constructed for the research on nuclear criticality safety. In this paper, the configuration of the facility is introduced; a series of critical experiments on uranyl nitrate solution is described later, which were performed for various uranium concentrations under different conditions, i.e. with or without neutron absorbers in the core and with or without water-reflector outside the core. Critical volume and the minimum 235U critical mass for different uranium concentrations are presented. Finally, theoretical analysis is made on the experimental results. (authors)

Np Incorporation into Uranyl Alteration Phases: A Quantum Mechanical Approach

International Nuclear Information System (INIS)

L.C. Huller; R.C. Win; U.Ecker

2006-01-01

Neptunium is a major contributor to the long-term radioactivity in a geologic repository for spent nuclear fuel (SNF) due to its long half-life (2.1 million years). The mobility of Np may be decreased by incorporation into the U 6+ phases that form during the corrosion of SNF. The ionic radii of Np (0.089nm) and U (0.087nm) are similar, as is their chemistry. Experimental studies have shown Np can be incorporated into uranyl phases at concentrations of ∼ 100 ppm. The low concentration of Np in the uranyl phases complicates experimental detection and presents a significant challenge for determining the incorporation mechanism. Therefore, we have used quantum mechanical calculations to investigate incorporation mechanisms and evaluate the energetics of Np substituting for U. CASTEP, a density functional theory based code that uses plane waves and pseudo-potentials, was used to calculate optimal H positions, relaxed geometry, and energy of different uranyl phases. The incorporation energy for Np in uranyl alteration phases was calculated for studtite, [(UO 2 )O 2 (H 2 O) 2 ](H 2 ) 2 , and boltwoodite, HK(UO 2 )(SiO 4 )* 1.5(H 2 O). Studtite is the rare case of a stable uranyl hydroxyl-peroxide mineral that forms in the presence of H 2 O 2 from the radiolysis of H 2 O. For studtite, two incorporation mechanisms were evaluated: (1) charge-balanced substitution of Np 5+ and H + for one U 6+ , and (2) direct substitution of Np 6+ for U 6+ . For boltwoodite, the H atomic positions prior to Np incorporation were determined, as well as the Np incorporation mechanisms and the corresponding substitution energies. The preferential incorporation of Np into different structure types of U 6+ minerals was also investigated. Quantum mechanical substitution energies have to be derived at Np concentrations higher than the ones found in experiments or expected in a repository. However, the quantum mechanical results are crucial for subsequent empirical force-field and Monte

Uranyl oxalate hydrates: structures and IR spectra

International Nuclear Information System (INIS)

Giesting, P.A.; Porter, N.J.; Burns, P.C.

2006-01-01

The novel compound (UO 2 ) 2 C 2 O 4 (OH) 2 (H 2 O) 2 (UrOx2A) and the previously studied compound UO 2 C 2 O 4 (H 2 O) 3 (UrOx3) have been synthesized by mild hydrothermal methods. Single crystal diffraction data collected at 125 K using MoK α radiation and a CCD-based area detector were used to solve and refine the crystal structures by full-matrix least-squares techniques to agreement indices (UrOx2A, UrOx3) wR 2 = 0.037, 0.049 for all data, and R1 0.015, 0.024 calculated for 1285, 2194 unique reflections respectively. The compound UrOx2A is triclinic, space group P1, Z = 1, a = 5.5353(4), b 6.0866(4), c = 7.7686(6) Aa, α = 85.6410(10) , β = 89.7740(10) , γ = 82.5090(10) , V = 258.74(3) Aa 3 . The compound UrOx3 is monoclinic, space group P2 1 /c, Z = 4, a = 5.5921(4), b = 16.9931(13), c = 9.3594(7) Aa, β = 99.5330(10) , V = 877.11(11) Aa 3 . The structures consist of chains of uranyl pentagonal bipyramids connected by oxalate groups and, in UrOx2A, hydroxyl groups; UrOx2A is also notable for its high (2:1) ratio of uranyl to oxalate groups, higher than any observed in other published structures of uranyl oxalates. The structure determined for UrOx3, previously studied by Jayadevan and Chackraburtty (1972); Mikhailov et al. (1999) is in agreement with the previous results; however, the increased precision of the present low-temperature structure refinement allows for the assignment of H atom positions based on the difference Fourier map of electron density. The infrared spectra of these two materials collected at room temperature are also presented and compared with previous work on uranyl oxalate systems. (orig.)

Investigation of uranyl sorbed to Wyoming montmorillonite at amphoteric and exchange sites by optical spectroscopy

International Nuclear Information System (INIS)

Morris, D.E.; Chisholm-Brause, C.J.; Berg, J.M.; McKinley, J.P.; Zachara, J.M.; Smith, S.C.

1993-01-01

Using optical spectroscopy, the authors have characterized aqueous uranyl (UO 2 2+ ) sorption complexes on a sodium-saturated Wyoming montmorillonite (SWy-1) at low and high ionic strength (IS, as NaClO 4 . McKinley et al. (1193), ACS Spring Meeting) have shown that uranyl uptake is suppressed at high IS at these pH values, reflecting increased cation competition for exchange sites, and an increase in the ratio of uranyl species sorbed on amphoteric edge sites to those in exchange sites. At higher pH, sorption is less dependent on IS, with complexation by amphoteric edge sites becoming dominant as pH increases. At low pH, emission spectra for uranyl sorbed to SWy-1 from solutions with high IS ([Na]/[U] > 1000) are distinct from those at low IS ([Na]/[U] < 10). The low IS spectra are dominanted by a short lifetime component (τ∼0.5μs), and have low integrated intensities (normalized for uranium concentration). However, gated detection clearly resolves an additional, longer-loved component. The high IS spectra have significant contributions form 2-3 longer-lived components (5<τ120μs), and have much stronger intensities. Based on comparison to solution data, these results suggest that the uranyl moiety in the exchange sites is strikingly similar to the fully aquated uranyl monomer in solution, whereas the uranyl species occupying the edge sites are structurally more similar to hydrolyzed uranyl species in solution. At higher pH values, the emission spectra represent composites of at least the two distinct spectra identified at lower pH. However, the ratios of the different components and thus the overall emission spectra vary as a function of ionic strength. These results demonstrate that several spectroscopically (and therefore structurally) distinct sorption complexes exist in exchange and edges of SWy-1

Contribution to the study of uranyl salts in butyl phosphate solutions; Contribution a l'etude des solutions de sels d'uranyle dans les phosphates butyliques

Energy Technology Data Exchange (ETDEWEB)

Coulon, A. [Commissariat a l' Energie Atomique, Fontenay-aux-Roses (France). Centre d' Etudes Nucleaires

1965-06-01

A spectroscopic study in the normal infrared region and involving the following associations: tri-alkyl phosphates (tri-butyl, tri-ethyl, tri-methyl), uranyl salts (nitrate, chloride, acetate) has confirmed the existence of an interaction between the phosphoryl group and the uranium atom, as shown by a movement of absorption band for the valency P = 0 from {approx} 1270 cm{sup -1} to {approx} 1180 cm{sup -1}. A study of the preparation, analysis and spectroscopy of the solids obtained by the precipitation of uranyl salts by acid butyl phosphates has been carried out. By infrared spectrophotometry it has been shown that the tri-butyl and di-butyl phosphates are associated in non-polar diluents even before the uranium is introduced. The extraction of uranyl salts from acid aqueous solutions by a diluted mixture of tri-butyl and di-butyl phosphates proceeds by different mechanisms according to the nature of the ion (nitrate or chloride). (author) [French] Une etude spectroscopique dans l'infrarouge moyen portant sur les associations: - phosphates trialcoyliques (tributylique - triethylique - trimethylique) - sels d'uranyle (nitrate, chlorure, acetate) a confirme l'existence d'une interaction entre le groupement phosphoryle et l'atome d'uranium, se manifestant par un deplacement de la bande d'absorption de la vibration de valence P = 0 de {approx} 1270 cm{sup -1} a {approx} 1180 cm{sup -1}. Une etude preparative, analytique et spectroscopique des solides obtenus par precipitation de sels d'uranyle par les phosphates butyliques acides a ete effectuee. La spectrophotomerie infrarouge met en evidence l'association, anterieure a toute introduction d'uranium, des phosphates tributylique et dibutylique dans des diluants non polaires. L'extraction de sels d'uranyle, d'une solution aqueuse acide par un melange dilue de phosphates tributylique et dibutylique, s'effectue suivant des processus differents a la

Chelation in metal intoxication

DEFF Research Database (Denmark)

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

2015-01-01

The present review provides an update of the general principles for the investigation and use of chelating agents in the treatment of intoxications by metals. The clinical use of the old chelators EDTA (ethylenediamine tetraacetate) and BAL (2,3-dimercaptopropanol) is now limited due to the incon......The present review provides an update of the general principles for the investigation and use of chelating agents in the treatment of intoxications by metals. The clinical use of the old chelators EDTA (ethylenediamine tetraacetate) and BAL (2,3-dimercaptopropanol) is now limited due...... to the inconvenience of parenteral administration, their own toxicity and tendency to increase the neurotoxicity of several metals. The hydrophilic dithiol chelators DMSA (meso-2,3-dimercaptosuccinic acid) and DMPS (2,3-dimercapto-propanesulphonate) are less toxic and more efficient than BAL in the clinical treatment...... 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...

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...

Preparation and thermogravimetric study of some uranyl phosphates

International Nuclear Information System (INIS)

Schaekers, J.M.

1970-10-01

The preparation of uranyl ammonium phosphate trihydrate (UAP = UO 2 NH 4 PO 4 .3H 2 O), acid uranyl phosphate tetrahydrate(AUP = UO 2 HPO 4 .4H 2 O) and neutral uranyl phosphate tetrahydrate (NUPT = (UO 2 ) 3 (PO 4 ) 2 .4H 2 O) was investigated during the data from the literature. The thermal decomposition in different atmospheres, such as air, oxygen, nitrogen and argon, was studied in the temperature range 25-1000 0 C. It was found that the pyrophosphate U 2 O 3 P 2 O 7 is a stable decomposition product of UAP as well as of AUP. A mixture of U 3 O 8 and U 2 O 3 P 2 O 7 is obtained when the NUPT is decomposed in an oxygen-free atmosphere. NUPT however is stable in an oxidising atmosphere. Hydrogen and carbon reductions were also carried out, and UO 2 or (UO) 2 P 2 O 7 as well as mixtures of these two products can be obtained, depending on the starting material and the reduction temperature. The different reduction and decomposition reactions were studied by means of thermogravimetric analysis, and activation energies were calculated where possible. I.R. spectral analysis was also used to identify various products with the same composition [af

Preparation of thin α-particle sources using poly-pyrrole films functionalized by a chelating agent

International Nuclear Information System (INIS)

Mariet, C.

2000-01-01

This work takes place in the scope of analysis of the α-particle emitting elements U, Pu and Am present in compound environmental matrix like sols and sediments. The samples diversity and above all the α-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 U and D 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)

Radioimmunodetection of tumor with Ga-67 labeled antibodies

International Nuclear Information System (INIS)

Furukawa, Takako; Endo, Keigo; Ohmomo, Yoshiro

1986-01-01

Antibodies against tumor associated antigen; anti-AFP polyclonal antibody, anti-thyroglobulin monoclonal antibody and anti-hCG monoclonal antibody, were labeled with Ga-67, using deferoxamine (DF) as a bifunctional chelating agent. The immunoreactivity and in vivo stability of the Ga-67 labeled antibodies were examined. The effect of DF conjugation to antibodies on the antigen-binding activity was evaluated by RIA and Scatchard analysis or tanned sheep red blood cell hemagglutination technique. When DF was conjugated to antibody at the molar ratio of 1 : 1, the antibody activity of the DF-conjugated antibodies was fully retained. Whereas, in heavily conjugated antibodies, the maximum antigen binding capacity was reduced. Biodistribution study in normal mice demonstrated the high in vivo stability of Ga-67 labeled antibodies. The labeling of DF-antibody conjugated with Ga-67 was performed easily and quickly, with a high labeling efficiency, requiring no further purification. Thus, this labeling method, providing in vivo stability of Ga-67 labeled antibody and full retention of immunoreactivity, would be useful for the radioimmunodetection of various cancers. (author)

Development of radioactivity labelling method of new antibody by using the antibody engineering

International Nuclear Information System (INIS)

Yamazaki, Takeshi; Nakajima, Osamu; Saito, Yoshiro; Hachisuka, Akiko; Tanaka, Toichi; Sawada, Junichi

1999-01-01

With an aim to develop a method to produce labelled antibodies with low immunogenicity, two recombinant fusion proteins; scFv-His and scFv-MTβ were produced using gene engineering techniques. The former was constructed with scFv-antibody and histidine hexamer, a metal-chelated protein (or peptide). The latter was done with scFv-antibody and β-domain of metallothionein. Then, antigen-binding activity and metal-binding activity of these fusion proteins were determined using gel-filtration chromatography and ELISA. The main antigen-binding activity of scFv-His preparation was detected in a domain of about 25-30 kDa, which agreed with the peak of 29 kDa corresponding to the presumed molecular weight for the protein. Whereas the antigen-binding activity of scFv-MTβ was found in a domain of 30-35 kDa, which agreed with 32 kDa, the presumed molecular weight of scFv-MTβ. Gel-filtration chromatography of scFv-His preparation after the addition of Cu 2+ ion revealed an optical absorption at 280 nm and a Cu-peak near at 14 kDa. These results suggested that the metal affinity of the histidine-hexamer was too weak to chelate Cu 2+ in a solution. The chromatography of scFv-MTβ preparation added with Cd 2+ showed a peak of Cd appeared around a position of about 20 kDa but the peak was not coincident with that of the antigen-binding activity (ca. 30 kDa), suggesting that the present preparation of scFv-MTβ had no Cd-binding activity due to metal-exchange reaction. Based on these results, problems on the production of recombinant scFv-antibody fused with metal-binding domain of cystein-binding type or histidine-binding one were discussed. (M.N.)

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

International Nuclear Information System (INIS)

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

2004-01-01

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 17β-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 -1 (3xSD of a standard containing 0 nmol l -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

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.

Ligand exchange in uranyl complexes in non-aqueous solutions: equilibrium properties

International Nuclear Information System (INIS)

Egozy, Y.; Weiss, S.

1976-01-01

The systems uranyl nitrate, tributylphosphate and 8-hydroxyquinoline or diphenylcarbazone were studied in chloroform, carbon tetrachloride and 1,2-dichloroethane at a number of temperatures. The nature of the complexes formed was determined and the equilibrium constants and several thermodynamic functions were measured. 8-hydroxyquinoline and diphenylcarbazone will be valuable as indicators for uranyl in kinetic studies. They are also interesting since they participate, along with tributylphosphate, in formation of synergistic complexes. (author)

Uranyl adsorption kinetics within silica gel: dependence on flow velocity and concentration

Science.gov (United States)

Dodd, Brandon M.; Tepper, Gary

2017-09-01

Trace quantities of a uranyl dissolved in water were measured using a simple optical method. A dilute solution of uranium nitrate dissolved in water was forced through nanoporous silica gel at fixed and controlled water flow rates. The uranyl ions deposited and accumulated within the silica gel and the uranyl fluorescence within the silica gel was monitored as a function of time using a light emitting diode as the excitation source and a photomultiplier tube detector. It was shown that the response time of the fluorescence output signal at a particular volumetric flow rate or average liquid velocity through the silica gel can be used to quantify the concentration of uranium in water. The response time as a function of concentration decreased with increasing flow velocity.

Inhibition Mechanism of Uranyl Reduction Induced by Calcium-Carbonato Complexes

Science.gov (United States)

Jones, M. E.; Bargar, J.; Fendorf, S. E.

2015-12-01

Uranium mobility in the subsurface is controlled by the redox state and chemical speciation, generally as minimally soluble U(IV) or soluble U(VI) species. In the presence of even low carbonate concentrations the uranyl-carbonato complex quickly becomes the dominant aqueous species; they are, in fact, the primary aqueous species in most groundwaters. Calcium in groundwater leads to ternary calcium-uranyl-carbonato complexes that limit the rate and extent of U(VI) reduction. This decrease in reduction rate has been attributed to surface processes, thermodynamic limitations, and kinetic factors. Here we present a new mechanism for the inhibition of ferrous iron reduction of uranyl-carbonato species in the presence of calcium. A series of experiments under variable Ca conditions were preformed to determine the role of Ca in the inhibition of U reduction by ferrous iron. Calcium ions in the Ca2UO2(CO3)3 complex sterically prevent the interaction of Fe(II) with U(VI), in turn preventing the Fe(II)-U(VI) distance required for electron transfer. The mechanism described here helps to predict U redox transformations in suboxic environments and clarifies the role of Ca in the fate and mobility of U. Electrochemical measurements further show the decrease of the U(VI) to U(V) redox potential of the uranyl-carbonato complex with decreasing pH suggesting the first electron transfer is critical determining the rate and extent of uranium reduction.

Isolation of a star-shaped uranium(V/VI) cluster from the anaerobic photochemical reduction of uranyl(VI)

International Nuclear Information System (INIS)

Chatelain, Lucile; White, Sarah; Scopelliti, Rosario; Mazzanti, Marinella

2016-01-01

Actinide oxo clusters are an important class of compounds due to their impact on actinide migration in the environment. The photolytic reduction of uranyl(VI) has potential application in catalysis and spent nuclear fuel reprocessing, but the intermediate species involved in this reduction have not yet been elucidated. Here we show that the photolysis of partially hydrated uranyl(VI) in anaerobic conditions leads to the reduction of uranyl(VI), and to the incorporation of the resulting U V species into the stable mixed-valent star-shaped U VI /U V oxo cluster [U(UO 2 ) 5 (μ 3 -O) 5 (PhCOO) 5 (Py) 7 ]. This cluster is only the second example of a U VI /U V cluster and the first one associating uranyl groups to a non-uranyl(V) center. The U V center in 1 is stable, while the reaction of uranyl(V) iodide with potassium benzoate leads to immediate disproportionation and formation of the U 12 IV U 4 V O 24 cluster {[K(Py) 2 ] 2 [K(Py)] 2 [U 16 O 24 (PhCOO) 24 (Py) 2 ]}.

Contribution to the study of the evaporation of aqueous uranyl nitrate solutions; Contribution a l'etude de l'evaporation des solutions aqueuses de nitrate d'uranyle

Energy Technology Data Exchange (ETDEWEB)

Billy, J [Commissariat a l' Energie Atomique, Fontenay-aux-Roses (France). Centre d' Etudes Nucleaires

1967-05-15

This work was carried out with a view to define the conditions under which is affected the concentration of aqueous uranyl nitrate solutions one of the steps in uranium extraction metallurgy. The first port is devoted to the experimental determination of the physical characteristics of aqueous uranyl nitrate solutions, from dilute to concentrated solutions. The second part of this work is devoted to the isothermal evaporation of solution a west ted-wall column; this chemical engineering study has been more particularly devoted to the definition of the influence of the dynamics of the liquid phase on the exchange of matter between the two phases in contact. (author) [French] La concentration par evaporation des solutions aqueuses de nitrate d'uranyle constitue une etape de la metallurgie de l'uranium dont ce travail a voulu preciser la connaissance. Dans ce but, une premiere partie a ete consacree a la determination experimentale de caracteristiques physiques des solutions aqueuses de nitrate d'uranyle, des solutions diluees aux solutions saturees. Dans une deuxieme partie, ce travail a porte sur l'evaporation isotherme des solutions dans une colonne a paroi mouillee; cette etude de genie chimique a ete plus particulierement orientee de facon a preciser l'influence de la dynamique de la phase liquide sur l'echange de matiere entre les deux phases en contact. (auteur)

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)

Observation of Radiolytic Field Alteration of the Uranyl Cation in Bicarbonate Solution

Energy Technology Data Exchange (ETDEWEB)

Snow, Lanee A.; McNamara, Bruce K.; Sinkov, Sergey I.; Cho, Herman M.; Friese, Judah I.

2006-12-01

In previous work we demonstrated that radiolysis of uranyl tris carbonate in near neutral pH to alkaline carbonate solutions, could be followed by 13C NMR. Radiolysis of the complex produced novel uranyl peroxo carbonate solution state species, whose structures depended on the pH and radiolytic dose rate. In this work, we investigate speciation of the uranyl carbonate trimer which is predominant in bicarbonate solution near pH 5.9. We observe radiolytically derived speciation to different mixed peroxy carbonate species than seen in the higher pH solutions. Auto radiolysis of uranium (VI) carbonate solutions between pH 5.9 and 7.2 is shown to alter the uranium speciation over relatively short periods of time and was followed by 13C NMR and visible spectrophotometry, using dissolved 233(UO2)3(CO3)6 6- both as the radiolysis source (D= 14.9 Gy/hr) and as a trap for the newly formed hydrogen peroxide. Direct addition of hydrogen peroxide to solutions of the uranyl-carbonate trimer is shown to reproduce the 13 C NMR signatures of the complexe(s) formed by radiolysis, but additionally a variety of new complexes are revealed. Ratios of H2O2/trimer < 1.5 produced a uranyl peroxo carbonate adduct, that is shown to be common to the radiolytically produced species. Ratios of H2O2/ trimer >1 resulted in formation of stable higher order peroxo carbonate complexes. The 13C NMR signatures and visible spectra of these complexes are described here. Rigorous characterization of the species is an ongoing effort.

Growth of uranyl hydroxide nanowires and nanotubes with electrodeposition method

International Nuclear Information System (INIS)

Wang Lin; Yuan Liyong; Chai Zhifang; Shi Weiqun

2013-01-01

Actinides nanomaterials have great potential applications in fabrication of novel nuclear fuel and spent fuel reprocessing in advanced nuclear energy system. However, the relative research so far still lacks systematic investigation on the synthetic methods for actinides nanomaterials. In this work, we use track-etched membranes as hard templates to synthesize uranium based nanomaterials with novel structures by electrodeposition method. Through electrochemical behavior investigations and subsequent product characterizations such as energy dispersive spectrometer (EDS), fourier transform infrared spectroscopy (FTIR), the chemical composition of deposition products have been confirmed as the uranyl hydroxide. More importantly, accurate control of morphology and structures (nanowires and nanotubes) could be achieved by carefully adjusting the growth parameters such as deposition time and deposition current density. It was found that the preferred morphology of electrodeposition products is nanowire when a low current density was applied, whereas nanotubes could be formed only under conditions of high current density and the short deposition time. The mechanism for the formation of nanowires in track-etched membranes is based on the precipitation of uranyl hydroxide from uranyl nitrate solution, according to the previous researches about obtaining nanostructures of hydroxides from nitrate salt solutions. And we have concluded that the formation of nanotubes is attributed to the hydrogen bubbles generated by water electrolysis under the condition of over-potential electro-reduction. The conveying of hydrogen bubbles plays the role of dynamic template which can prevent the complete filling of uranyl hydroxide in the channels. Additionally, we transform the chemical composition of deposition products from uranyl hydroxide to triuranium octoxide by calcining them at 500 and 800 degree centigrade, respectively, and SEM results show the morphologies of nanowires and

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...

Chelation therapy after the Trial to Assess Chelation Therapy: results of a unique trial

Science.gov (United States)

Avila, Maria D.; Escolar, Esteban; Lamas, Gervasio A.

2014-01-01

Purpose of review EDTA chelation therapy has been in off-label use for the treatment of atherosclerosis. We review the results of the first large-scale randomized trial of this treatment. Recent findings The trial to assess chelation therapy was a $30 million National Institutes of Health-funded study of the safety and efficacy of EDTA-based chelation infusions in 1708 post-myocardial infarction (MI) patients. The trial to assess chelation therapy demonstrated a significant (P = 0.035) 18% reduction in a combined primary endpoint of death, MI, stroke, coronary revascularization, or hospitalization for angina. In diabetic patients the benefit was more extreme, with a 41% relative reduction in risk (P = 0.0002) and a 43% reduction in total mortality (P = 0.011). Safety data were favorable. A reduction of oxidative stress by chelation of toxic metals has been proposed as a possible mechanism of action. Summary Recent research suggests that EDTA chelation may be a well-tolerated and effective treatment for post-MI patients. Future replication and mechanistic studies are important prior to implementation in all post-MI patients. PMID:25023079

Preparation and properties of uranyl bromate monohydrate

International Nuclear Information System (INIS)

Weigel, F.

1983-01-01

Uranyl bromate monohydrate UO 2 (BrO 3 ) 2 .H 2 O was obtained as a greenish-yellow solid by the metathesis of a uranyl sulfate solution with a stoichiometric amount of barium bromate solution. On evaporation of the supernatant of the precipitated BaSO 4 a greenish-yellow syrup was obtained which, on dehydration with anhydrous carbon tetrachloride, yielded a free-flowing greenish-yellow powder with stoichiometry UO 2 (BrO 3 ) 2 .H 2 O. Powder diffraction diagrams of UO 2 (BrO 3 ) 2 .H 2 O obtained using the Guinier method yielded an orthorhombic lattice (space group, Pbcn (no. 60)) with a = 8.533 +- 0.003 A, b = 7.639 +- 0.003 A and c = 12.293 +- 0.004 A; the X-ray density was 4.507 g cm -3 . The compound was characterized by chemical analysis, IR spectroscopy and differential thermal analysis. (Auth.)

Re-evaluating neptunium in uranyl phases derived from corroded spent fuel

International Nuclear Information System (INIS)

Fortner, J. A.; Finch, R. J.; Kropf, A. J.; Cunnane, J. C.; Chemical Engineering

2004-01-01

Interest in mechanisms that may control radioelement release from corroded commercial spent nuclear fuel (CSNF) has been heightened by the selection of the Yucca Mountain site in Nevada as the repository for high-level nuclear waste in the United States. Neptunium is an important radionuclide in repository models owing to its relatively long half-life and its high aqueous mobility as neptunyl [Np(V)O+2]. The possibility of neptunium sequestration into uranyl alteration phases produced by corroding CSNF would suggest-a process for lowering neptunium concentration and subsequent migration from a geologic repository. However, there remains little experimental evidence that uranyl compounds will, in fact, serve as long-term host phases for the retention of neptunium under conditions expected in a deep geologic repository. To directly explore this possibility, we examined specimens of uranyl alteration phases derived from humid-air-corroded CSNF by X-ray absorption spectroscopy to better determine neptunium uptake in these phases. Although neptunium fluorescence was readily observed from as-received CSNF, it was not observed from the uranyl alteration rind. We establish upper limits for neptunium incorporation into CSNF alteration phases that are significantly below previously reported concentrations obtained by using electron energy loss spectroscopy (EELS). We attribute the discrepancy to a plural-scattering event that creates a spurious EELS peak at the neptunium-MV energy

The thermal denigration in fluid-bed to make uranyl product

International Nuclear Information System (INIS)

Ma Zhenrong; Cui Yulin; Zhu Changbing; Fan Chuanyong; Liu Yanfeng

2010-01-01

Nuclear fuel reprocessing plant used the thermal denigration to high concentration of uranyl nitrate solution in fluid-bed to make uranyl product. First the uranyl nitrate solution were concentrated in evaporator, into 300 gU/L, 600 gU/L, 750 gU/L and 1000 gU/L.When the fluid-bed was in good fluidity state at 320 degree C, the solution was sprayed all over the surface of the fine crystal seeds through the dual-channel air-blast nozzles to make new crystal seed and to make them grow up. The denigration reaction occurred when the internal temperature of the fluid-bed was kept at about 300 degree C by the outside and inside heat apparatus. The product were transported crossing the valve and spiral transfer to pack. The tail gas was purified and discharged. Through the fluid-bed's running, the variation discipline of temperature and the pressure, the effect curve of the quality of product accumulated to pressure drop were determined. At the same time, the gentrification temperature, the distributed heat and the transfer mode were tested. (authors)

Variable Denticity in Carboxylate Binding to the Uranyl Coordination Complexes

International Nuclear Information System (INIS)

Groenewold, G.S.; De Jong, Wibe A.; Oomens, Jos; Van Stipdonk, Michael J.

2010-01-01

Tris-carboxylate complexes of the uranyl (UO2)2+ cation with acetate and benzoate were generated using electrospray ionization mass spectrometry, and then isolated in a Fourier transformion cyclotron resonance mass spectrometer. Wavelength-selective infrared multiple photon dissociation (IRMPD) of the tris-acetatouranyl anion resulted in a redox elimination of an acetate radical, which was used to generate an IR spectrum that consisted of six prominent absorption bands. These were interpreted with the aid of density functional theory calculations in terms of symmetric and antisymmetric -CO2 stretches of both the monodentate and bidentate acetate, CH3 bending and umbrella vibrations, and a uranyl O-U-O asymmetric stretch. The comparison of the calculated and measured IR spectra indicated that the tris-acetate complex contained two acetate ligands bound in a bidentate fashion, while the third acetate was monodentate. In similar fashion, the tris-benzoate uranyl anion was formed and photodissociated by loss of a benzoate radical, enabling measurement of the infrared spectrum that was in close agreement with that calculated for a structure containing one monodentate, and two bidentate benzoate ligands.

99mTC-dextran-antibody conjugates. Labelling procedures

International Nuclear Information System (INIS)

Marquez, M.; Westlin, J.E.; Nilsson, S.; Holmberg, A.R.

1996-01-01

Dextran forms stable chelates with 99m Tc, a radionuclide with ideal properties for planar scintigraphic and tomographic imaging. This study investigates some of the factors of importance to the formation of 99m Tc-dextran. The complex was used for the technetium labelling of a monoclonal antibody. Two radiolabelling methods were studied: Direct dextran labelling with the reductant dissolved in HCl and labelling via a weak 'transfer' chelator (tartaric acid) with the reductant dissolved in ethanol. Different conditions during the labelling reaction were studied. Finally, dextran was coupled to a monoclonal anticytokeratin antibody and the conjugate was subsequently radiolabelled with 99m Tc. Gel filtration (GFR) and thin layer chromatography (TLC) were compared as methods for estimation of the labelling efficiency. When using 10-500 μM of ligand, 5-100 μM SnC1 2 with 10-500 MBq of technetium at pH7 incubated for 10-15 min, the radiolabelling seemed optimal (70-75% labelling efficiency). It was found that 100 μM tartaric acid used as a weak intermediate chelator with SnCl 2 dissolved in ethanol improved the reproducibility of the labelling. The labelling efficiency was not affected by either the presence of oxygen or the addition of an oxygen scavenger during the labelling incubation. In general, TLC showed higher labelling efficiencies than GFR, indicating inadequate separation of the different moieties. (orig.)

Highly Efficient Interception and Precipitation of Uranium(VI) from Aqueous Solution by Iron-Electrocoagulation Combined with Cooperative Chelation by Organic Ligands.

Science.gov (United States)

Li, Peng; Zhun, Bao; Wang, Xuegang; Liao, PingPing; Wang, Guanghui; Wang, Lizhang; Guo, Yadan; Zhang, Weimin

2017-12-19

A new strategy combining iron-electrocoagulation and organic ligands (OGLs) cooperative chelation was proposed to screen and precipitate low concentrations (0-18.52 μmol/L) of uranium contaminant in aqueous solution. We hypothesized that OGLs with amino, hydroxyl, and carboxyl groups hydrophobically/hydrophilically would realize precuring of uranyl ion at pH electrocoagulation would achieve faster and more efficient uranium precipitation. Experimentally, the strategy demonstrated highly efficient uranium(VI) precipitation efficiency, especially with hydrophilic macromolecular OGLs. The uranium removal efficiency at optimized experimental condition reached 99.65%. The decrease of zeta potential and the lattice enwrapping between U-OGLs chelates and flocculation precursor were ascribed to the enhanced uranium precipitation activity. Uranium was precipitated as oxides of U(VI) or higher valences that were easily captured in aggregated micelles under low operation current potential. The actual uranium tailing wastewater was treated, and a satisfied uranium removal efficiency of 99.02% was discovered. After elution of the precipitated flocs, a concentrated uranium solution (up to 106.52 μmol/L) with very few other metallic impurities was obtained. Therefore, the proposed strategy could remove uranium and concentrate it concurrently. This work could provide new insights into the purification and recovery of uranium from aqueous solutions in a cost-effective and environmentally friendly process.

Energy transfer and quenching processes of excited uranyl ion and lanthanide ions in solutions

International Nuclear Information System (INIS)

Yamamura, Tomoo; Tomiyasu, Hiroshi

1995-01-01

Deactivation processes of photoexcited uranyl ion by various lanthanide ions in aqueous solution were studied. Each lanthanide ions show different interaction with excited uranyl ion depending on its lowest excited energy level, the number of 4f electrons and the acid concentration of the solution. (author)

Kinetic investigation of uranyl-uranophile complexation. 1. Macrocyclic kinetic effect and macrocyclic protection effect

International Nuclear Information System (INIS)

Tabushi, I.; Yoshizawa, A.

1986-01-01

Equilibria and rates of ligand-exchange reactions between uranyl tricarbonate and dithiocarbamates and between uranyl tris-(dithiocarbamates) and carbonate were studied under a variety of conditions. The dithiocarbamates used were acyclic diethyl-dithiocarbamate and macrocyclic tris(dithiocarbamate). The acyclic ligand showed a triphasic (successive three-step) equilibrium with three different equilibrium constants while the macrocyclic ligand showed a clear monophasic (one-step) equilibrium with a much larger stability constant for the dithiocarbamate-uranyl complex. The macrocyclic ligand showed the S/sub N/2-type ligand-exchange rate in the forward as well as reverse process, while the first step of the acyclic ligand-exchange reaction proceeded via the S/sub N/1-type mechanism. This kinetic macrocyclic effect on molecularity is interpreted as the result of a unique topological requirement of uranyl complexation. The macrocyclic ligand also exhibited a clear protection effect, leading to the large stability constant. 19 references, 10 figures, 2 tables

Development of chelate tagging method of protein at low temperature

International Nuclear Information System (INIS)

Oida, Shigeru; Sekiya, Keizo

1999-01-01

This study aimed at development of a protein labelling method at a low temperature, available for functional proteins, such as antibodies and enzymes mostly unstable at high temperatures. A solution of anti-mouse IgG antibody added with EDTA was incubated with 51 CrCl 3 at 4degC for 24 hours. After stopping the reaction with 100-fold amount of EDTA-2Na, the solution was fractionated into antibody fraction and metal fraction by HPLC. After incubation, non-specific Cr adsorption on the antibody in no relation to the chelate reagent was chased with 10-fold amount of CrCl 3 . To remove free Cr, the sample solution was incubated with 10 to 50-fold ICB-EDTA solution containing N,N-dimethyl-formamide. Then, the amount of Cr-labelling on the antibody was determined. In Western-blotting, chick actin was applied onto SDS-polyacrylamide gel electrophoresis. One part of the lane was stained with brilliant-blue and the other was transferred on nitrocellulose membrane by semi-dry method and stained with panceau-S. Anti-actin monoclonal antibody and anti-mouse IgG antibody were used as the first antibody and the second one, respectively. When incubated with ICB-EDTA for 3 days, labelling reached the maximum level. Although labelling of the second antibody was performed with maleimido-C 3 -benzyl EDTA and 45 Ca as a substitute for 51 Cr, the rate of labelling was lower than the rate for a combination of ICB-EDTA and 51 Cr. Autoradiography of the anti-mouse IgG preparation after SDS-acrylamide gel electrophoresis revealed that radioactivity was detected on the site of H-chain but not L-chain. This indicates that 51 Cr labelling of protein is stable even under the conditions of SDS denaturation. (M.N.)

Uranyl Ion Complexes with Long-Chain Aliphatic α,ω-Dicarboxylates and 3d-Block Metal Counterions.

Science.gov (United States)

Thuéry, Pierre; Harrowfield, Jack

2016-03-07

Twelve new complexes were obtained from reaction of uranyl ions with the aliphatic dicarboxylic acids HOOC-(CH2)n-2-COOH (H2Cn; n = 7-10 and 12) under solvo-hydrothermal conditions, in the presence of 3d-block metal ions (Mn(2+), Fe(3+), Co(2+), Ni(2+), and Cu(2+)) and 2,2'-bipyridine (bipy) or 1,10-phenanthroline (phen). In contrast to previously reported triple-stranded helicates obtained with C9(2-) and C12(2-), all these complexes crystallize as polymeric one-dimensional (1D) or two-dimensional (2D) species. [Fe(bipy)3][(UO2)2(C7)3]·3H2O (1), [Cu(phen)2]2[(UO2)3(C7)4(H2O)2]·2H2O (2), and [Cu(bipy)2]2[(UO2)2(C9)3] (6), in which the 3d cation was reduced in situ, are 1D ladderlike polymers displaying tetra- or hexanuclear rings, of sufficient width to encompass two counterions in 2 and 6. The three complexes [Co(phen)3][(UO2)3(C8)3(O)]·H2O (3), [Ni(phen)3][(UO2)3(C8)3(O)]·H2O (4) and [Co(phen)3][(UO2)3(C9)3(O)]·H2O (5) contain bis(μ3-oxo)-bridged tetranuclear secondary building units, and they crystallize as deeply furrowed 2D assemblies. Depending on the nature of the counterion, C10(2-) gives [Ni(bipy)3][(UO2)2(C10)3]·2H2O (7), a 2D network displaying elongated decanuclear rings containing the counterions, or [Mn(phen)3][(UO2)2(C10)3]·6H2O (8), [Co(phen)3][(UO2)2(C10)3]·7H2O (9), and [Ni(phen)3][(UO2)2(C10)3]·7H2O (10), which consist of 2D assemblies with honeycomb topology; the hexanuclear rings in 8-10 are chairlike and occupied by one counterion and two uranyl groups from neighboring layers. Two complexes of the ligand with the longest chain, C12(2-), are reported. [UO2(C12)(bipy)] (11) is a neutral 1D species in which bipy chelates the uranyl ion and plays an important role in the packing through π-stacking interactions. Two polymeric units, 1D and 2D, coexist in the complex [Ni(bipy)3][(UO2)2(C12)3][UO2(C12)(H2O)2]·H2O (12); the 2D network has the honeycomb topology, but the hexanuclear rings are markedly convoluted, with local features akin to

Water structure and aqueous uranyl(VI) adsorption equilibria onto external surfaces of beidellite, montmorillonite, and pyrophyllite: results from molecular simulations.

Science.gov (United States)

Greathouse, Jeffery A; Cygan, Randall T

2006-06-15

Molecular dynamics simulations were performed to provide a systematic study of aqueous uranyl adsorption onto the external surface of 2:1 dioctahedral clays. Our understanding of this key process is critical in predicting the fate of radioactive contaminants in natural groundwaters. These simulations provide atomistic detail to help explain experimental trends in uranyl adsorption onto natural media containing smectite clays. Aqueous uranyl concentrations ranged from 0.027 to 0.162 M. Sodium ions and carbonate ions (0.027-0.243 M) were also present in the aqueous regions to more faithfully model a stream of uranyl-containing groundwater contacting a mineral system comprised of Na-smectite. No adsorption occurred near the pyrophyllite surface, and there was little difference in uranyl adsorption onto the beidellite and montmorillonite, despite the difference in location of clay layer charge between the two. At low uranyl concentration, the pentaaquouranyl complex dominates in solution and readily adsorbs to the clay basal plane. At higher uranyl (and carbonate) concentrations, the mono(carbonato) complex forms in solution, and uranyl adsorption decreases. Sodium adsorption onto beidellite occurred both as inner- and outer-sphere surface complexes, again with little effect on uranyl adsorption. Uranyl surface complexes consisted primarily of the pentaaquo cation (85%) and to a lesser extent the mono(carbonato) species (15%). Speciation diagrams of the aqueous region indicate that the mono(carbonato)uranyl complex is abundant at high ionic strength. Oligomeric uranyl complexes are observed at high ionic strength, particularly near the pyrophyllite and montmorillonite surfaces. Atomic density profiles of water oxygen and hydrogen atoms are nearly identical near the beidellite and montmorillonite surfaces. Water structure therefore appears to be governed by the presence of adsorbed ions and not by the location of layer charge associated with the substrate. The water

Kinetic studies of uranyl ion adsorption on acrylonitrile (AN) / polyethylene glycol (PEG) interpenetrating networks (IPN)

International Nuclear Information System (INIS)

Aycik, G.A.; Gurellier, R.

2004-01-01

The kinetics of the adsorption of uranyl ions on amidoximated acrylonitrile (AN)/ polyethylene glycol (PEG) interpenetrating network (IPNs) from aqueous solutions was studied as a function of time and temperature. Adsorption analyses were performed for definite uranyl ion concentrations of 1x10 -2 M and at four different temperatures as 290K, 298K, 308K and 318K. Adsorption time was increased from zero to 48 hours. Adsorption capacities of uranyl ions by PEG/AN IPNS were determined by gamma spectrometer. The results indicate that adsorption capacity increases linearly with increasing temperature. The max adsorption capacity was found as 602 mgu/g IPN at 308K. Adsorption rate was evaluated from the curve plotted of adsorption capacity versus time, for each temperature. Rate constants for uranyl ions adsorption on amidoximated ipns were calculated for 290K, 298K, 308K and 318K at the solution concentration of 1x10 -2 M . The results showed that as the temperature increases the rate constant increases exponentially too. The mean activation energy of uranyl ions adsorption was found as 34.6 kJ/mole by using arrhenius equation. (author)

Dehydration-driven evolution of topological complexity in ethylamonium uranyl selenates

Energy Technology Data Exchange (ETDEWEB)

Gurzhiy, Vladislav V., E-mail: vladgeo17@mail.ru [Department of Crystallography, St. Petersburg State University, University Emb. 7/9, 199034 St. Petersburg (Russian Federation); Krivovichev, Sergey V. [Department of Crystallography, St. Petersburg State University, University Emb. 7/9, 199034 St. Petersburg (Russian Federation); Tananaev, Ivan G. [Far Eastern Federal University, Suhanova st. 8, 690950 Vladivostok (Russian Federation)

2017-03-15

Single crystals of four novel uranyl selenate and selenite-selenate oxysalts with protonated ethylamine molecules, (C{sub 2}H{sub 8}N){sub 2}[(UO{sub 2})(SeO{sub 4}){sub 2}(H{sub 2}O)](H{sub 2}O) (I), (C{sub 2}H{sub 8}N){sub 3}[(UO{sub 2})(SeO{sub 4}){sub 2}(HSeO{sub 4})] (II), (C{sub 2}H{sub 8}N)[(UO{sub 2})(SeO{sub 4})(HSeO{sub 3})] (III), and (C{sub 2}H{sub 8}N)(H{sub 3}O)[(UO{sub 2})(SeO{sub 4}){sub 2}(H{sub 2}O)] (IV) have been prepared by isothermal evaporation from aqueous solutions. Uranyl-containing 1D and 2D units have been investigated using topological approach and information-based complexity measurements that demonstrate the evolution of structural units and the increase of topological complexity with the decrease of H{sub 2}O content. - Graphical abstract: Single crystals of four novel uranyl selenate and selenite-selenate oxysalts with protonated ethylamine molecules have been prepared by isothermal evaporation from aqueous solutions. Structural analysis and information-based topological complexity calculations points to the possible sequence of crystalline phases formation, showing both topological and structural branches of evolution. - Highlights: • Single crystals of four novel uranyl oxysalts were prepared by evaporation method. • The graph theory was used for investigation of topologies of structural units. • Dehydration processes drives the evolution of topological complexity of 1D and 2D structural units.

Antibody-dendrimer conjugates: the number, not the size of the dendrimers, determines the immunoreactivity.

Science.gov (United States)

Wängler, C; Moldenhauer, G; Eisenhut, M; Haberkorn, U; Mier, W

2008-04-01

Radioimmunotherapy using antibodies with favorable tumor targeting properties and high binding affinity is increasingly applied in cancer therapy. The potential of this valuable cancer treatment modality could be further improved by increasing the specific activity of the labeled proteins. This can be done either by coupling a large number of chelators which leads to a decreased immunoreactivity or by conjugating a small number of multimeric chelators. In order to systematically investigate the influence of conjugations on immunoreactivity with respect to size and number of the conjugates, the anti-EGFR antibody hMAb425 was reacted with PAMAM dendrimers of different size containing up to 128 chelating agents per conjugation site. An improved dendrimer synthesis protocol was established to obtain compounds of high homogeneity suitable for the formation of defined protein conjugates. The quantitative derivatization of the PAMAM dendrimers with DOTA moieties and the characterization of the products by isotopic dilution titration using (111)In/(nat)In are shown. The DOTA-containing dendrimers were conjugated with high efficiency to hMAb425 by applying Sulfo-SMCC as cross-linking agent and a 10- to 25-fold excess of the thiol-containing dendrimers. The determination of the immunoreactivities of the antibody-dendrimer conjugates by FACS analysis revealed a median retained immunoreactivity of 62.3% for 1.7 derivatization sites per antibody molecule, 55.4% for 2.8, 27.9% for 5.3, and 17.1% for 10.0 derivatization sites per antibody but no significant differences in immunoreactivity for different dendrimer sizes. These results show that the dendrimer size does not influence the immunoreactivity of the derivatized antibody significantly over a wide molecular weight range, whereas the number of derivatization sites has a crucial effect.

Precipitation characteristics of uranyl ions at different pHs depending on the presence of carbonate ions and hydrogen peroxide.

Science.gov (United States)

Kim, Kwang-Wook; Kim, Yeon-Hwa; Lee, Se-yoon; Lee, Jae-Won; Joe, Kih-Soo; Lee, Eil-Hee; Kim, Jong-Seung; Song, Kyuseok; Song, Kee-Chan

2009-04-01

This work studied the dissolution of uranium dioxide and precipitation characteristics of uranyl ions in alkaline and acidic solutions depending on the presence of carbonate ions and H2O2 in the solutions at different pHs controlled by adding HNO3 or NaOH in the solution. The chemical structures of the precipitates generated in different conditions were evaluated and compared by using XRD, SEM, TG-DT, and IR analyses together. The sizes and forms of the precipitates in the solutions were evaluated, as well. The uranyl ions were precipitated in the various forms, depending on the solution pH and the presences of hydrogen peroxide and carbonate ions in the solution. In a 0.5 M Na2CO3 solution with H2O2, where the uranyl ions formed mixed uranyl peroxy-carbonato complexes, the uranyl ions were precipitated as a uranium peroxide of UO4(H20)4 at pH 3-4, and precipitated as a clarkeite of Na2U2Ox(OH)y(H2O)z above pH 13. In the same carbonate solution without H2O2, where the uranyl ions formed uranyl tris-carbonato complex, the uranyl ions were observed to be precipitated as a different form of clarkeite above pH 13. The precipitate of uranyl ions in a nitrate solution without carbonate ions and H2O2 at a high pH were studied together to compare the precipitate forms in the carbonate solutions.

Contribution to the study of uranyl salts in butyl phosphate solutions

International Nuclear Information System (INIS)

Coulon, A.

1965-06-01

A spectroscopic study in the normal infrared region and involving the following associations: tri-alkyl phosphates (tri-butyl, tri-ethyl, tri-methyl), uranyl salts (nitrate, chloride, acetate) has confirmed the existence of an interaction between the phosphoryl group and the uranium atom, as shown by a movement of absorption band for the valency P = 0 from ∼ 1270 cm -1 to ∼ 1180 cm -1 . A study of the preparation, analysis and spectroscopy of the solids obtained by the precipitation of uranyl salts by acid butyl phosphates has been carried out. By infrared spectrophotometry it has been shown that the tri-butyl and di-butyl phosphates are associated in non-polar diluents even before the uranium is introduced. The extraction of uranyl salts from acid aqueous solutions by a diluted mixture of tri-butyl and di-butyl phosphates proceeds by different mechanisms according to the nature of the ion (nitrate or chloride). (author) [fr

Uranyl sorption onto alumina

International Nuclear Information System (INIS)

Jacobsson, A.M.M.

1997-01-01

The mechanism for the adsorption of uranyl onto alumina from aqueous solution was studied experimentally and the data were modeled using a triple layer surface complexation model. The experiments were carried out at low uranium concentrations (9 x 10 -11 --5 x 10 -8 M) in a CO 2 free environment at varying electrolyte concentrations (0.01--1 M) and pH (4.5--12). The first and second acid dissociation constants, pK a1 and pK a2 , of the alumina surface were determined from potentiometric titrations to be 7.2 ± 0.6 and 11.2 ± 0.4, respectively. The adsorption of uranium was found to be independent of the electrolyte concentration. The authors therefore conclude that the uranium binds as an inner sphere complex. The results were modeled using the code FITEQL. Two reactions of uranium with the surface were needed to fit the data, one forming a uranyl complex with a single surface hydroxyl and the other forming a bridged or bidentate complex reacting with two surface hydroxyls of the alumina. There was no evidence from these experiments of site heterogeneity. The constants used for the reactions were based in part on predictions made utilizing the Hard Soft Acid Base, HSAB, theory, relating the surface complexation constants to the hydrolysis of the sorbing metal ion and the acid dissociation constants of the mineral oxide surface

Expanding the Library of Uranyl Amide Derivatives: New Complexes Featuring the tert-Butyldimethylsilylamide Ligand.

Science.gov (United States)

Pattenaude, Scott A; Coughlin, Ezra J; Collins, Tyler S; Zeller, Matthias; Bart, Suzanne C

2018-04-16

New uranyl derivatives featuring the amide ligand, -N(SiHMe 2 ) t Bu, were synthesized and characterized by X-ray crystallography, multinuclear NMR spectroscopy, and absorption spectroscopies. Steric properties of these complexes were also quantified using the computational program Solid-G. The increased basicity of the free ligand -N(SiHMe 2 ) t Bu was demonstrated by direct comparison to -N(SiMe 3 ) 2 , a popular supporting ligand for uranyl. Substitutional lability on a uranyl center was also demonstrated by exchange with the -N(SiMe 3 ) 2 ligand. The increased basicity of this ligand and diverse characterization handles discussed here will make these compounds useful synthons for future reactivity.

Design of one evaporation system for uranyl nitrate solution

International Nuclear Information System (INIS)

Mancilla Romero, R.J.

1975-01-01

The authors propose an instant evaporation system with recirculation of the concentrated solution to raise the concentration from 50 to 1500 g of uranium per litre of solution. The capacity of the plant is to be 14.1 kg of uranium per hour. The main equipment used in the system is as follows: 1. Ring-type heat exchanger, for increasing the temperature of the mixture of fresh and recirculated solution from 80 to 115 0 C; 2. Separation tank, in which instant evaporation is carried out. The absolute pressure inside the tank will be 500 mmHg, with steam separation from a concentrated (78.5 wt.%) uranyl nitrate solution; 3. Desuperheater-condenser of horizontal tubular type for condensing water vapour and recovering any uranyl nitrate that may have been entrained; 4. Storage tank for the concentrate, with a capacity for one day's normal operation, and a heating coil to prevent crystallization of the concentrated solution; 5. Two storage tanks for feed and condensate with capacity for one day's normal operation; 6. Supporting structure for the above components. Virtually all equipment in contact with the uranyl nitrate solution will be made of 304 stainless steel. Saturated steam at 143.3 0 C will be required. The cost of the proposed system is $543 030.00. (author)

Uranyl sensor based on a N,N?-bis(salicylidene)-2-hydroxy-phenylmethanediamine and multiwall carbon nanotube electrode

International Nuclear Information System (INIS)

Sayed Mehdi Ghoreishi; Mohsen Behpour; Samaneh Mazaheri; Hossein Naeimi

2012-01-01

The electrochemical determination of uranyl was investigated by using carbon paste electrode modified with a Schiff base namely N,N'-bis(salicylidene)-2-hydroxy-phenylmethanediamine (SHPMD/CPE) and also in the presence of carbon nanotube (SHPMD/CNT/CPE). The both modified electrodes displayed an irreversible peak at E pa = 0.798 V versus Ag/AgCl. The electrocatalytic reduction of uranyl has been studied on SHPMD/CNT/CPE, using cyclic and differential pulse voltammetry, chronocoulometry and linear sweep techniques. Electrochemical parameters including the diffusion coefficient (D), the electron transfer coefficient (α), the ionic exchange current (i) and the redox reaction rate constant (K) were determined for the reduction of uranyl on the surface of the modified electrodes. Linear range concentration is 0.002-0.6 μmol L -1 and the detection limit of uranyl is 0.206 nmol L -1 . The proposed method was used to detect uranyl in natural waters and good recovery was achieved. (author)

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

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.

Article Commentary: 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.

Isolation of a star-shaped uranium(V/VI) cluster from the anaerobic photochemical reduction of uranyl(VI)

Energy Technology Data Exchange (ETDEWEB)

Chatelain, Lucile; White, Sarah; Scopelliti, Rosario; Mazzanti, Marinella [Ecole Polytechnique Federale de Lausanne (EPFL) (Switzerland). Inst. de Sciences et Ingenierie Chimiques

2016-11-07

Actinide oxo clusters are an important class of compounds due to their impact on actinide migration in the environment. The photolytic reduction of uranyl(VI) has potential application in catalysis and spent nuclear fuel reprocessing, but the intermediate species involved in this reduction have not yet been elucidated. Here we show that the photolysis of partially hydrated uranyl(VI) in anaerobic conditions leads to the reduction of uranyl(VI), and to the incorporation of the resulting U{sup V} species into the stable mixed-valent star-shaped U{sup VI}/U{sup V} oxo cluster [U(UO{sub 2}){sub 5}(μ{sub 3}-O){sub 5}(PhCOO){sub 5}(Py){sub 7}]. This cluster is only the second example of a U{sup VI}/U{sup V} cluster and the first one associating uranyl groups to a non-uranyl(V) center. The U{sup V} center in 1 is stable, while the reaction of uranyl(V) iodide with potassium benzoate leads to immediate disproportionation and formation of the U{sub 12}{sup IV}U{sub 4}{sup V}O{sub 24} cluster {[K(Py)_2]_2[K(Py)]_2[U_1_6O_2_4(PhCOO)_2_4(Py)_2]}.

Safe use and waste disposal of uranyl acetate

International Nuclear Information System (INIS)

Sanchez, A.; Calvo, S.; Caparros, G.; Gallego, E.; Rascon, J.; Valladares, M.C.

2006-01-01

Radioactive labelled molecules are widely used in Biological Research Centres. The most common radioisotopes are: 32 P, 33 P, 35 S, 3 H, 14 C, 125 I and 45 Ca.Due to the inherent risk in the manipulation of these radiation unsealed sources, in these radioactive installations there are established radiological protection programs to reduce this potential risk and the professional exposure in the manipulation and in the radioactive waste generated. In these Biological Research Centres we used techniques with other radioactive products less used, that we must to control. It is the case of the use of uranyl acetate. Uranyl acetate is a uranium salt used in the preparation of samples for analysis in the electron microscope. Although the amounts used are relatively small, both the chemical and radiological toxicities of these compounds are significant and require working whit that some cautions, with the main emphasis on avoiding the possibility of inhalation of fine particulates or vapours. Due to changes in the Spanish regulations for this product, it was necessary to establish a specific control program in its manipulation. The purpose of this work is the accomplishment of specific protocols for the acquisition, manipulation, contamination measurements, inspections of the work zone and waste management, in order to minimize the risks in the manipulation of uranyl acetate,as well as apply the knowledge and use of specific norms for working with this product. (authors)

Safe use and waste disposal of uranyl acetate

Energy Technology Data Exchange (ETDEWEB)

Sanchez, A.; Calvo, S.; Caparros, G.; Gallego, E.; Rascon, J.; Valladares, M.C. [Centro de Biologia Molecular, Madrid (Spain)

2006-07-01

Radioactive labelled molecules are widely used in Biological Research Centres. The most common radioisotopes are: {sup 32}P,{sup 33}P, {sup 35}S,{sup 3}H,{sup 14}C,{sup 125}I and {sup 45}Ca.Due to the inherent risk in the manipulation of these radiation unsealed sources, in these radioactive installations there are established radiological protection programs to reduce this potential risk and the professional exposure in the manipulation and in the radioactive waste generated. In these Biological Research Centres we used techniques with other radioactive products less used, that we must to control. It is the case of the use of uranyl acetate. Uranyl acetate is a uranium salt used in the preparation of samples for analysis in the electron microscope. Although the amounts used are relatively small, both the chemical and radiological toxicities of these compounds are significant and require working whit that some cautions, with the main emphasis on avoiding the possibility of inhalation of fine particulates or vapours. Due to changes in the Spanish regulations for this product, it was necessary to establish a specific control program in its manipulation. The purpose of this work is the accomplishment of specific protocols for the acquisition, manipulation, contamination measurements, inspections of the work zone and waste management, in order to minimize the risks in the manipulation of uranyl acetate,as well as apply the knowledge and use of specific norms for working with this product. (authors)

Corrosion evaluation of uranyl nitrate solution evaporator and denitrator in Tokai reprocessing plant

International Nuclear Information System (INIS)

Yamanaka, Atsushi; Hashimoto, Kowa; Uchida, Toyomi; Shirato, Yoji; Isozaki, Toshihiko; Nakamura, Yoshinobu

2011-01-01

The Tokai reprocessing plant (TRP) adopted the PUREX method in 1977 and has reprocessed spent nuclear fuel of 1140 tHM (tons of heavy metals) since then. The reprocessing equipment suffers from various corrosion phenomena because of high nitric acidity, solution ion concentrations, such as uranium, plutonium, and fission products, and temperature. Therefore, considering corrosion performance in such a severe environment, stainless steels, titanium steel, and so forth were employed as corrosion resistant materials. The severity of the corrosive environment depends on the nitric acid concentration and the temperature of the solution, and uranium in the solution reportedly does not significantly affect the corrosion of stainless steels and controls the corrosion rates of titanium steel. The TRP equipment that handles uranyl nitrate solution operates at a low nitric acid concentration and has not experienced corrosion problems until now. However, there is a report that corrosion rates of some stainless steels increase in proportion to rising uranium concentrations. The equipment that handles the uranyl nitrate solution in the TRP includes the evaporators, which concentrate uranyl nitrate to a maximum concentration of about 1000 gU/L (grams of uranium per liter), and the denitrator, where uranyl nitrate is converted to UO 3 powder at about 320degC. These equipments are therefore required to grasp the degree of the progress of corrosion to handle high-temperature and high-concentration uranyl nitrate. The evaluation of this equipment on the basis of thickness measurement confirmed only minor corrosion and indicated that the equipment would be fully adequate for future operation. (author)

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.

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

International Nuclear Information System (INIS)

Arnold, John

2015-01-01

The uranyl cation (UO 2 2+ ) 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.

Photochemistry and exciplex of the uranyl ion in aqueous solution

International Nuclear Information System (INIS)

Marcantonatos, M.D.

1980-01-01

The effects of acidity, temperature, self-quenching and H-donor concentration on the luminescent state of the aqua-uranyl(VI) ion have been studied in aqueous acidic nitrate and perchlorate solution. The detailed results cannot be explained by any single simple mechanism such as radiative, non-radiative or spontaneous collisional quenching, or irreversible hydrogen abstraction from water. Quantitative analysis of the results shows a far more complex mechanism, involving the adiabatic formation of the species *UO 2 H 2+ and *U 2 O 4 H 4+ , as already proposed by the author. This mechanism is supported by state and m.o. correlations. The abstraction of hydrogen from water is shown to take place by H atom transfer in a *uranyl-water complex intermediate, rather than by attack of H + on the fully occupied πsub(u) orbitals of uranium(V) in a well-defined uranyl water complex with strong charge transfer character. A qualitative description of the exciplex *U 2 O 4 H 4+ is shown to be possible in a v.b. formalism and the origin of its radiative properties is discussed on this basis. (author)

Production of U3O8 by uranyl formate precipitation and calcination in a full-scale pilot facility

International Nuclear Information System (INIS)

Kendrick, L.S.; Wilson, W.A.; Mosley, W.C.

1984-08-01

The uranyl formate process for the production of U 3 O 8 with a controlled particle size has been extensively studied on a laboratory scale. Based on this study, a pilot-scale facility (the Uranyl Formate Facility) was built to investigate the key steps of the process on a larger scale. These steps were the precipitation of a uranyl formate monohydrate salt and the calcination of this salt to U 3 O 8 . Tests of the facility and process were conducted at conditions recommended by the laboratory-scale studies for a full-scale production facility. These tests demonstrated that U 3 O 8 of the required particle size for the PM process can be produced on a plant scale by the calcination of uranyl formate crystals. The performance of the U 3 O 8 produced by the uranyl formate process in fuel tube fabrication was also investigated. Small-scale extrusion tests of U 3 O 8 -Al cores which used the U 3 O 8 produced in the Uranyl Formate Facility were conducted. These tests demonstrated that the U 3 O 8 quality was satisfactory for the PM process

Determination of the stability of the uranyl ion sipped in τ-hydrogen phosphate of zirconium in sodic form

International Nuclear Information System (INIS)

Ordonez R, E.; Fernandez V, S.M.; Drot, R.; Simoni, E.

2005-01-01

The stability of the uranyl sipped in the zirconium τ-hydrogen phosphate in sodic form (τ-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 -4 and 10 -5 of uranyl nitrate and with ion forces of 0.1 and 0.5 M of NaClO 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 τ-NaZP, that makes to this material appropriate to retain to the uranyl in solution to high ion forces and in acid media. (Author)

Uranyl oxo activation and functionalization by metal cation coordination

International Nuclear Information System (INIS)

Arnold Polly, L.; Pecharman, A. F.; Hollis, E.; Parsons, S.; Love, J. B.; Yahia, A.; Maron, L.; Yahia, A.; Maron, L.

2010-01-01

The oxo groups in the uranyl ion [UO 2 ] 2+ - one of many oxo cations formed by metals from across the periodic table - are particularly inert, which explains the dominance of this ion in the laboratory and its persistence as an environmental contaminant. In contrast, transition metal oxo (M=O) compounds can be highly reactive and carry out difficult reactions such as the oxygenation of hydrocarbons. Here we show how the sequential addition of a lithium metal base to the uranyl ion constrained in a 'Pacman' environment results in lithium coordination to the U=O bonds and single-electron reduction. This reaction depends on the nature and stoichiometry of the lithium reagent and suggests that competing reduction and C-H bond activation reactions are occurring. (authors)

Treatment of uranyl nitrate and flouride solutions

International Nuclear Information System (INIS)

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

1977-01-01

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

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

International Nuclear Information System (INIS)

Blake, Diane A.

2003-01-01

The goals for the 3-year project period are (1) to test and validate the present uranium sensor and develop protocols for its use at the NABIR Field Research Center; (2) to develop new reagents that will provide superior performance for the present hand-held immunosensor; and (3) to develop new antibodies that will permit this sensor to also measure other environmental contaminants (chromium, mercury, and/or DTPA). Sensor design modifications are underway via international collaborations. New reagents that will provide superior performance for the present hand-held immunosensor are being prepared and tested. New methods have been developed, to produce recombinant forms of metal-specific monoclonal antibodies for use with the sensor. Site-directed mutagenesis experiments are underway to determine the mechanisms of binding. Immunization experiments with sheep and rabbits to develop new recombinant forms of antibodies to metal-chelate complexes (chromium, mercury, and/or DTPA) have been initiated

The treatment of uranyl nitrate from the AMOR process for VKTA Rossendorf

International Nuclear Information System (INIS)

Boessert, W.; Krempl, R.; Miller, J.W.

2003-01-01

The blending of uranyl nitrate solutions at VKTA and its subsequent treatment at BNFL-Sellafield is a significant step towards the safe and effective treatment of these enriched uranyl nitrate solutions. Overall the integration of the expertise of the international company BNFL/Westinghouse will lead to the achievement of a successful solution. This success has involved the integration of the project management and operational facilities of BNFL Sellafield with the local planning, design and manufacture capacities of Westinghouse Reaktor GmbH. (orig.)

The study of conjugation of anti-CD20 monoclonal antibody for labeling with metallic or lanthanides radionuclides

International Nuclear Information System (INIS)

Akanji, Akinkunmi Ganiyu

2012-01-01

Lymphomas are malignancies or cancers that start from the malign transformation of a lymphocyte in the lymphatic system. Generally, lymphomas start from the lymph nodes or from the agglomeration of the lymphatic tissues, organs like stomach, intestines, in some cases it can involve the bone marrow and the blood, it can also disseminate to other organs. Lymphomas are divided in two major categories: Hodgkin lymphoma and non-Hodgkin lymphoma (NHL). Patient with NHL are generally treated with radiotherapy alone or combined with immunotherapy using monoclonal antibody rituximab (MabThera®). Currently, monoclonal antibodies (Acm) conjugated with bifunctional chelate agents and radiolabeled with metallic or lanthanides radionuclides are a treatment reality for patients with NHL by the principle of radioimmunotherapy (RIT). This study focused on the conditions of conjugation of Acm rituximab (MabThera®) with bifunctional chelating agents DOTA and DTPA. Various parameters were studied: method of Acm purification, conditions of Acm conjugation, the method for determination of number of chelate agent coupled to the Acm, method for purification of the conjugated antibody Acm, conditions of labeling of the conjugated antibody with lutetium-177, method of purification of the radiolabeled immuno conjugate, method of radiochemical purity (RP), specific binding in vitro Raji cells (Human Burkitt) and biological distribution performed in normal Balb-c mouse. The three methodologies employed in pre-purification of Acm (dialysis, size exclusion chromatograph and dial filtration) demonstrated to be efficient; they provided sample recovery exceeding 90%. However, the methodology of dial filtration presents minimal sample loss, and gave the final recovery of the sample in micro liters; thereby facilitating sample use in subsequent experiments. Numbers of chelators attached to the Acm molecule was proportional to the molar ratio studied. When we evaluated the influence of different

Reactive transport of uranyl: fixation mode on silica and goethite; experiments in columns and closed reactors; simulations

International Nuclear Information System (INIS)

Gabriel, U.

1998-01-01

Uranium contaminated areas are found in mine waste disposal sites, former military areas, etc. The present study focuses on the identification or mechanisms which may lead contaminated soils to become a sudden potential threat to surface and ground waters. Mechanisms were studied on model material at two levels. On the molecular scale, the complexation of uranyl at trace metal concentrations was investigated with amorphous silica. Complexation is shown to occur via the formation of surface complexes, characterised by different time-resolved laser-induced luminescence spectra and life times and stoichiometry. On the macro-scale the transport behaviour of uranyl in a cristobalite-goethite-carbonate-uranyl system was investigated with laboratory column and batch experiments. Uranium mobility was found to be controlled by the interaction between physical transport and a reversible, rate-controlled, fixation reaction. Sorption was shown to be an ensemble of competing solution and surface complexation reactions, leading to an apparent non-linear (Langmuir-like) adsorption isotherm. Finally the impact of a sudden change in background geochemistry was studied. Conditions leading to a dramatic mobilization of uranium from mildly contaminated systems were experimentally identified. Maximal uranyl concentration are controlled by the total extractable uranyl in the system and limited by uranyl solubility. Evolution of the background geochemical conditions is thus an important part of contaminated sites risk assessment. (author)

Investigation of uranyl phosphite interaction with some amides

International Nuclear Information System (INIS)

Avduevskaya, K.A.; Ragulina, N.B.; Rozanov, I.A.; Mukhajlov, Yu.N.; Kanishcheva, A.S.; Grevtseva, T.G.

1981-01-01

Uranyl (amide) phosphitocomplexes of [UO 2 HPO 3 H 2 OAA]xH 2 O, [UO 2 HPO 3 (AA) 2 ], [UO 2 HPO 3 H 2 O DMC], [UO 2 HPO 3 H 2 ODMFA], [UO 2 HPO 3 DAMA] and UO 2 HPO 3 x2FAxH 2 O compositions, where AA-acetamide; DMC-N, N-dimetyl carbamide, DMFA-dimetyl formamide; DAMA-diamide of malonic acid; FA-formamide, are separated, identified and investigated. Derivatives of mono substituted uranyl phosphite of UO 2 (H 2 PO 3 ) 2 x2FA and [UO 2 (H 2 PO 3 ) 2 H 2 O]x2TMC composition (where TMC-tetramethyl carbamide), are synthesized. Structures of complexes with DAMA, TMC, DMFA and acid dimethyl-ammonium diphosphitouranylate-(CH 3 ] 2 NH 2 x[UO 2 (HPO 3 ) 3 (H 2 PO 3 )] are investigated [ru

Investigation of uranyl nitrate complexes with trialkylphosphine oxides

International Nuclear Information System (INIS)

Kobets, L.V.; Kopashova, I.M.; Dik, T.A.; Volodin, I.A.; Kovalenko, M.A.; Semenij, V.Ya.

1982-01-01

Using the methods of vibrational spectroscopy and thermal analysis a number of uranyl complexes with trialkylphosphine oxides of the general formula UO 2 (NO 3 ) 2 x2R 3 PO, where R-C 2 H 5 -C 10 H 21 have been studied. Infrared and Raman spectra are interpreted according to vibration types. Comparison of vibrational spectra of the complexes in solid phase and solutions of organic solvents permitted to find the differences in position and amount of acids responsible for complexing. It is detected that in the series of complexes investigated the strength of uranyl bond with phosphoryl group oxygen practically remains stable, whereas degree of covalence of nitrate groups is observed. The pointed out peculiarities are interpreted proceeding from the presence of bridge nitrate groups in the structure of the complexes. Thermal stability of the complexes is studied, chemism of their decomposition being suggested

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.)

Uranyl oxo activation and functionalization by metal cation coordination

Energy Technology Data Exchange (ETDEWEB)

Arnold Polly, L; Pecharman, A F; Hollis, E; Parsons, S; Love, J B [Univ Edinburgh, EaStCHEM Sch Chem, Edinburgh EH9 3JJ, Midlothian (United Kingdom); Yahia, A; Maron, L [Univ Toulouse 3, LPCNO, UMR 5215, INSA, CNRS, F-31077 Toulouse 4 (France); Yahia, A; Maron, L [Univ Montpellier 2, ENSCM, CNRS, ICSM, UMR 5257, CEA, Ctr Marcoule, F-30207 Bagnols Sur Ceze (France)

2010-07-01

The oxo groups in the uranyl ion [UO{sub 2}]{sup 2+} - one of many oxo cations formed by metals from across the periodic table - are particularly inert, which explains the dominance of this ion in the laboratory and its persistence as an environmental contaminant. In contrast, transition metal oxo (M=O) compounds can be highly reactive and carry out difficult reactions such as the oxygenation of hydrocarbons. Here we show how the sequential addition of a lithium metal base to the uranyl ion constrained in a 'Pacman' environment results in lithium coordination to the U=O bonds and single-electron reduction. This reaction depends on the nature and stoichiometry of the lithium reagent and suggests that competing reduction and C-H bond activation reactions are occurring. (authors)

Complete removal of uranyl nitrate from tissue matrix using supercritical fluid extraction

International Nuclear Information System (INIS)

Kumar, R.; Sivaraman, N.; Senthil Vadivu, E.; Srinivasan, T.G.; Vasudeva Rao, P.R.

2003-01-01

The removal of uranyl nitrate from tissue matrix has been studied with supercritical carbon dioxide modified with methanol alone as well as complexing reagents dissolved in methanol. A systematic study of various complexing agents led to the development of an extraction procedure for the quantitative recovery of uranium from tissue matrix with supercritical carbon dioxide modified with methanol containing small quantities of acetylacetone. The drying time and temperature employed in loading of uranyl nitrate onto tissue paper were found to influence the extraction efficiency significantly

Mouse-specific antibody responses to a monoclonal antibody during repeated immunoscintigraphy investigations: Comparison of antibody titres and imaging studies in a rat model

International Nuclear Information System (INIS)

Pimm, M.V.; Gribben, S.J.; Markham, A.J.; Perkins, A.C.

1990-01-01

As a model for human mouse-specific antibody responses in patients undergoing immunoscintigraphy, we have investigated in rats the production of mouse-specific antibodies (MA) to the mouse monoclonal antibody 791T/36. At intervals of between 5 and 16 weeks the rats were given repeated cycles of intravenous (IV) injections of antibody with or without a simultaneous intradermal (ID) injection. The IV dose was 60 μg/kg, a dose similar to that used in many clinical immunoscintigraphy studies. The ID injection was 2 μg, which mimicks the skin test dose often given in clinical imaging protocols. The study was carried out with both 131 I-labelled antibody and with antibody labelled with 111 In by DTPA chelation. MA was measured with a passive haemagglutination assay using sheep red blood cells coated with the monoclonal antibody. Of rats given ID injections of unlabelled antibody at the same time as the IV imaging doses, 9/20 produced MA during 4 cycles of injections. In contrast, only 2/16 rats given only the IV dose produced MA. Both 131 I- and 111 In-labelled antibody appeared equally immunogenic with 5/18 and 6/18 overall responders, respectively. The production of MA was associated with a significant perturbation in the biodistribution of the IV dose of labelled antibody as seen by gamma-camera imaging of the rats given 111 In-labelled antibody. There was clearance of immune complexes to the liver, this organ accumulating up to 90% of the whole body count rate of radiolabel. MA titres of between 1/100 and 1/78000 caused equal perturbation of biodistribution, although below 1/100 the effect was more variable. (orig.)

Manganese(II) chelate contrast media

International Nuclear Information System (INIS)

Rocklage, S.M.; Quay, S.C.

1994-01-01

New chelate forming compounds for use as contrast media in NMR imaging are described. Especially mentioned are manganese(II) ion chelates of N,N' dipyridoxaldiamine, N,N' diacetic acid, and salts and esters thereof. 1 fig

Cyclic phosphopeptides to rationalize the role of phosphoamino acids in uranyl binding to biological targets

Energy Technology Data Exchange (ETDEWEB)

Starck, Matthieu; Laporte, Fanny A.; Oros, Stephane; Sisommay, Nathalie; Gathu, Vicky; Lebrun, Colette; Delangle, Pascale [INAC/SyMMES, UMR5819, Universite Grenoble Alpes, CEA, CNRS, Grenoble (France); Solari, Pier Lorenzo [Synchrotron SOLEIL, L' orme des Merisiers, Saint-Aubin, Gif-sur-Yvette (France); Creff, Gaelle; Den Auwer, Christophe [Institut de Chimie de Nice, UMR7272, Universite Cote d' Azur, Nice (France); Roques, Jerome [Institut de Physique Nucleaire d' Orsay, CNRS-IN2P3, Univ. Paris-Sud, Universite Paris-Saclay (France)

2017-04-19

The specific molecular interactions responsible for uranium toxicity are not yet understood. The uranyl binding sites in high-affinity target proteins have not been identified yet and the involvement of phosphoamino acids is still an important question. Short cyclic peptide sequences, with three glutamic acids and one phosphoamino acid, are used as simple models to mimic metal binding sites in phosphoproteins and to help understand the mechanisms involved in uranium toxicity. A combination of peptide design and synthesis, analytical chemistry, extended X-ray absorption fine structure (EXAFS) spectroscopy, and DFT calculations demonstrates the involvement of the phosphate group in the uranyl coordination sphere together with the three carboxylates of the glutamate moieties. The affinity constants measured with a reliable analytical competitive approach at physiological pH are significantly enhanced owing to the presence of the phosphorous moiety. These findings corroborate the importance of phosphoamino acids in uranyl binding in proteins and the relevance of considering phosphoproteins as potential uranyl targets in vivo. (copyright 2017 Wiley-VCH Verlag GmbH and Co. KGaA, Weinheim)

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. Copyright © 2012 Elsevier B.V. All rights reserved.

Controlled deprotection and reorganization of uranyl oxo groups in a binuclear macrocyclic environment

International Nuclear Information System (INIS)

Jones, Guy M.; Arnold, Polly L.; Love, Jason B.

2012-01-01

The silylated uranium(V) dioxo complex [(Me_3SiOUO)_2(L)_2] is inert to oxidation, but after two-electron reduction to [(Me_3SiOUO)_2(L)]"2"-, it can be desilylated to form [OU(μ-O)_2UO(L)_2]"2"- with reinstated uranyl character. Removal of the silyl group uncovers new redox and oxo rearrangement chemistry for uranium, thus reforming the uranyl motif and involving the U"V"I"/"V couple in dioxygen reduction. [de

Decomposition rates of radiopharmaceutical indium chelates in serum

International Nuclear Information System (INIS)

Yeh, S.M.; Meares, C.F.; Goodwin, D.A.

1979-01-01

The rates at which six small aminopolycarboxylate chelates of trivalent 111 In and three protein-bound chelates of 111 In deliver indium to the serum protein transferrin have been studied in sterile human serum at pH 7.3, 37 deg C. Sterically hindered chelates containing a substituent on an ethylene carbon of EDTA decompose with rates in the range 0.03 to 0.11% per day - one to two orders of magnitude slower than other chelates. Only small differences are observed between rates of decomposition for low-molecular-weight chelates and for protein-bound chelates having analogous structures. (author)

SEPARATION OF BARIUM VALUES FROM URANYL NITRATE SOLUTIONS

Science.gov (United States)

Tompkins, E.R.

1959-02-24

The separation of radioactive barium values from a uranyl nitrate solution of neutron-irradiated uranium is described. The 10 to 20% uranyl nitrate solution is passed through a flrst column of a cation exchange resin under conditions favoring the adsorption of barium and certain other cations. The loaded resin is first washed with dilute sulfuric acid to remove a portion of the other cations, and then wash with a citric acid solution at pH of 5 to 7 to recover the barium along with a lesser amount of the other cations. The PH of the resulting eluate is adjusted to about 2.3 to 3.5 and diluted prior to passing through a smaller second column of exchange resin. The loaded resin is first washed with a citric acid solution at a pH of 3 to elute undesired cations and then with citric acid solution at a pH of 6 to eluts the barium, which is substantially free of undesired cations.

Uranyl nitrate-exposed rat alveolar macrophages cell death: Influence of superoxide anion and TNF α mediators

International Nuclear Information System (INIS)

Orona, N.S.; Tasat, D.R.

2012-01-01

Uranium compounds are widely used in the nuclear fuel cycle, military and many other diverse industrial processes. Health risks associated with uranium exposure include nephrotoxicity, cancer, respiratory, and immune disorders. Macrophages present in body tissues are the main cell type involved in the internalization of uranium particles. To better understand the pathological effects associated with depleted uranium (DU) inhalation, we examined the metabolic activity, phagocytosis, genotoxicity and inflammation on DU-exposed rat alveolar macrophages (12.5–200 μM). Stability and dissolution of DU could differ depending on the dissolvent and in turn alter its biological action. We dissolved DU in sodium bicarbonate (NaHCO 3 100 mM) and in what we consider a more physiological vehicle resembling human internal media: sodium chloride (NaCl 0.9%). We demonstrate that uranyl nitrate in NaCl solubilizes, enters the cell, and elicits its cytotoxic effect similarly to when it is diluted in NaHCO 3 . We show that irrespective of the dissolvent employed, uranyl nitrate impairs cell metabolism, and at low doses induces both phagocytosis and generation of superoxide anion (O 2 − ). At high doses it provokes the secretion of TNFα and through all the range of doses tested, apoptosis. We herein suggest that at DU low doses O 2 − may act as the principal mediator of DNA damage while at higher doses the signaling pathway mediated by O 2 − may be blocked, prevailing damage to DNA by the TNFα route. The study of macrophage functions after uranyl nitrate treatment could provide insights into the pathophysiology of uranium‐related diseases. -- Highlights: ► Uranyl nitrate effect on cultured macrophages is linked to the doses and independent of its solubility. ► At low doses uranyl nitrate induces generation of superoxide anion. ► At high doses uranyl nitrate provokes secretion of TNFα. ► Uranyl nitrate induces apoptosis through all the range of doses tested.

Uranyl nitrate-exposed rat alveolar macrophages cell death: Influence of superoxide anion and TNF α mediators

Energy Technology Data Exchange (ETDEWEB)

Orona, N.S. [School of Science and Technology, National University of General Martín, Avda Gral Paz 5445 (1650) San Martín, Buenos Aires (Argentina); Tasat, D.R., E-mail: deborah.tasat@unsam.edu.ar [School of Science and Technology, National University of General Martín, Avda Gral Paz 5445 (1650) San Martín, Buenos Aires (Argentina); School of Dentistry, University of Buenos Aires, M. T. de Alvear 2142 (1122), Buenos Aires (Argentina)

2012-06-15

Uranium compounds are widely used in the nuclear fuel cycle, military and many other diverse industrial processes. Health risks associated with uranium exposure include nephrotoxicity, cancer, respiratory, and immune disorders. Macrophages present in body tissues are the main cell type involved in the internalization of uranium particles. To better understand the pathological effects associated with depleted uranium (DU) inhalation, we examined the metabolic activity, phagocytosis, genotoxicity and inflammation on DU-exposed rat alveolar macrophages (12.5–200 μM). Stability and dissolution of DU could differ depending on the dissolvent and in turn alter its biological action. We dissolved DU in sodium bicarbonate (NaHCO{sub 3} 100 mM) and in what we consider a more physiological vehicle resembling human internal media: sodium chloride (NaCl 0.9%). We demonstrate that uranyl nitrate in NaCl solubilizes, enters the cell, and elicits its cytotoxic effect similarly to when it is diluted in NaHCO{sub 3}. We show that irrespective of the dissolvent employed, uranyl nitrate impairs cell metabolism, and at low doses induces both phagocytosis and generation of superoxide anion (O{sub 2}{sup −}). At high doses it provokes the secretion of TNFα and through all the range of doses tested, apoptosis. We herein suggest that at DU low doses O{sub 2}{sup −} may act as the principal mediator of DNA damage while at higher doses the signaling pathway mediated by O{sub 2}{sup −} may be blocked, prevailing damage to DNA by the TNFα route. The study of macrophage functions after uranyl nitrate treatment could provide insights into the pathophysiology of uranium‐related diseases. -- Highlights: ► Uranyl nitrate effect on cultured macrophages is linked to the doses and independent of its solubility. ► At low doses uranyl nitrate induces generation of superoxide anion. ► At high doses uranyl nitrate provokes secretion of TNFα. ► Uranyl nitrate induces apoptosis through

Fluid extraction using carbon dioxide and organophosphorus chelating agents

Science.gov (United States)

Smart, Neil G.; Wai, Chien M.; Lin, Yuehe; Kwang, Yak Hwa

1998-01-01

Methods for extracting metalloid and metal species from a solid or liquid material by exposing the material to a fluid solvent, particularly supercritical CO.sub.2, and a chelating agent are described. The chelating agent forms a chelate with the species, the chelate being soluble in the fluid to allow removal of the species from the material. In preferred embodiments the extraction solvent is supercritical CO.sub.2 and the chelating agent comprises an organophosphorous chelating agent, particularly sulfur-containing organophosphorous chelating agents, including mixtures of chelating agents. Examples of chelating agents include monothiophosphinic acid, di-thiophosphinic acid, phosphine sulfite, phosphorothioic acid, and mixtures thereof. The method provides an environmentally benign process for removing metal and metalloids from industrial waste solutions, particularly acidic solutions. Both the chelate and the supercritical fluid can be regenerated and the contaminant species recovered to provide an economic, efficient process.

Effects of nitrate, fulvate, phosphate, phthalate, salicylate and catechol on the sorption of uranyl onto SiO2. A comparative study

International Nuclear Information System (INIS)

Zhang Hongxia; Wen Chuanxi; Tao Zuyi; Wu Wangsuo

2011-01-01

We have performed a large number of batch sorption experiments of uranyl onto SiO 2 and examined the effects of nitrate or ionic strength, phosphate, fulvic acid(FA), phthalic acid (PH), salicylic acid (SA), and catechol (CA) on the uranyl sorption onto SiO 2 . Three sorption edges and three sorption isotherms at ionic strengths 0.05, 0.1, and 0.5 mol/L KNO 3 were used to investigate the effect of ionic strength or nitrate on the sorption and the Langmuir, Freundlich, and Dubinin-Radushkevich models are used to simulate the sorption isotherms, respectively. Five sorption edges in the presence of phosphate, FA, PH, SA, and CA were compared with that in the absence of complexing ligand. The results suggest that the effect of complexation of uranyl with nitrate on the uranyl sorption can be negligible and the sorption can be described Freundlich and D-R model very well. The positive effect of phosphate on the uranyl sorption was found, though the extent of effect was decreased with increasing pH. The positive effect and the negative effect of FA on the uranyl sorption were found at low pH and high pH ranges, respectively. The sorption edge of uranyl sorption remained unaffected in the presence of PH in the pH 2-10. In the presence of SA, the no effect and the negative effect on the uranyl sorption were, respectively, found at low pH and high pH ranges. The negative effect of CA on the uranyl sorption was found in the pH 2-10. (author)

Synthesis of pyrimidine carboxamide derivatives catalyzed by uranyl

African Journals Online (AJOL)

2014-09-02

(Received September 2, 2014; revised January 1, 2016). ABSTRACT. An efficient and simple method was developed for the synthesis pyrimidine-5-carboxamides using. UO2(NO3)2.6H2O catalyst under conventional and microwave irradiation. The synthesis of dihydropyrimidine using uranyl nitrate had shown many ...

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.

Studies on conductance of uranyl soaps

International Nuclear Information System (INIS)

Mehrotra, K.N.; Sharma, M.; Gahlaut, A.S.

1987-01-01

Specific conductance of uranyl soaps in dimethylformamide indicates two critical micelle concentrations CMC(I) and CMC(II). The value of CMC(II) decreases with the increase in chain length of the soap, whereas CMC(I) does not vary at all. The results show that the soaps behave as simple electrolyte. The major conductance at infinite dilution (μsub(o)) and dissociation constant (K) of these soaps have been evaluated. (author). 12 refs

Density Functional Studies on the Complexation and Spectroscopy of Uranyl Ligated with Acetonitrile and Acetone Derivatives

International Nuclear Information System (INIS)

Schoendorff, George E.; Windus, Theresa L.; De Jong, Wibe A.

2009-01-01

The coordination of nitrile (acetonitrile, propionitrile, and benzonitrile) and carbonyl (formaldehyde, ethanal, and acetone) ligands to the uranyl dication (UO22+) has been examined using density functional theory (DFT) utilizing relativistic effective core potentials (RECPs). Complexes containing up to six ligands have been modeled for all ligands except formaldehyde, for which no minimum could be found. A comparison of relative binding energies indicates that five coordinate complexes are predominant while a six coordinate complex involving propionitrile ligands might be possible. Additionally, the relative binding energy and the weakening of the uranyl bond is related to the size of the ligand and, in general, nitriles bind more strongly to uranyl than carbonyls.

Enhancement of uranyl fluorescence using trimesic acid: Ligand sensitization and co-fluorescence

Energy Technology Data Exchange (ETDEWEB)

Maji, S. [Chemistry Group, Materials Chemistry Division, Indira Gandhi Centre for Atomic Research, Kalpakkam 603102 (India); Viswanathan, K.S., E-mail: vish@igcar.gov.in [Chemistry Group, Materials Chemistry Division, Indira Gandhi Centre for Atomic Research, Kalpakkam 603102 (India)

2011-09-15

Trimesic acid (TMA) was shown to sensitize and enhance uranyl fluorescence in aqueous medium, with the enhancement being a maximum at pH 5.0. Fluorescence spectra and lifetime data together suggest that TMA complexes with uranyl (UO{sub 2}{sup 2+}). The fluorescence of UO{sub 2}{sup 2+} in its acid complex is further enhanced by more than two orders of magnitude following the addition of Y{sup 3+}; a process referred to as co-fluorescence, leading to the possibility of detecting uranium at sub ng/mL level. The present study demonstrates, for the first time, fluorescence enhancement of the uranyl species due to co-fluorescence. - Highlights: > Trimesic acid was shown to sensitize and enhance the fluorescence of uranium in aqueous medium. > This ligand also exhibited co-fluorescence of uranium with Y{sup 3+}. > To the best of our knowledge this is the first report of co-fluorescence in uranium. > The enhancement of uranium fluorescence, resulted in detection limits in the ng/mL regime.

Relationship among chelator adherence, change in chelators, and quality of life in thalassemia.

Science.gov (United States)

Trachtenberg, Felicia L; Gerstenberger, Eric; Xu, Yan; Mednick, Lauren; Sobota, Amy; Ware, Hannah; Thompson, Alexis A; Neufeld, Ellis J; Yamashita, Robert

2014-10-01

Thalassemia, a chronic blood disease, necessitates life-long adherence to blood transfusions and chelation therapy to reduce iron overload. We examine stability of health-related quality of life (HRQOL) in thalassemia and adherence to chelation therapy over time, especially after changes in chelator choice. Thalassemia Longitudinal Cohort participants in the USA, UK, and Canada completed the SF-36v2 (ages 14+) and the PF-28 CHQ (parents of children health status) at baseline who made a single change in chelator, but declined among participants with multiple changes and/or high iron burden (worse health status). Mental health improved among participants with lower iron burden, but iron overload was negatively associated with social functioning. Adherence did not significantly change over follow-up except for an increase after a change from deferoxamine (DFO) infusion to oral deferasirox (p = 0.03). Predictors of lower adherence for adults/adolescents at follow-up included side effects, smoking, younger age, problems preparing DFO, increased number of days per week DFO prescribed, and lower physical quality of life . Strategies to balance medical needs with family, work, and personal life may assist in adherence.

Electrospray ionization of uranyl-citrate complexes

Science.gov (United States)

Somogyi, Árpád; Pasilis, Sofie P.; Pemberton, Jeanne E.

2007-09-01

Results presented here demonstrate the usefulness of electrospray ionization and gas-phase ion-molecule reactions to predict structural and electronic differences in complex inorganic ions. Electrospray ionization of uranyl citrate solutions generates positively and negatively charged ions that participate in further ion-molecule reactions in 3D ion trap and FT-ICR mass analyzers. Most ions observed are derived from the major solution uranyl-citrate complexes and involve species of {(UO2)2Cit2}2-, (UO2)3Cit2, and {(UO2)3Cit3}3-, where Cit indicates the citrate trianion, C6H5O73-. In a 3D ion trap operated at relatively high pressure, complex adducts containing solvent molecules, alkali and ammonium cations, and nitrate or chloride anions are dominant, and proton/alkali cation (Na+, K+) exchange is observed for up to six exchangeable protons in an excess of alkali cations. Adduct formation in a FT-ICR cell that is operated at lower pressures is less dominant, and direct detection of positive and negative ions of the major solution complexes is possible. Multiply charged ions are also detected, suggesting the presence of uranium in different oxidation states. Changes in uranium oxidation state are detected by He-CID and SORI-CID fragmentation, and certain fragments undergo association reactions in trapping analyzers, forming "exotic" species such as [(UO2)4O3]-, [(UO2)4O4]-, and [(UO2)4O5]-. Ion-molecule reactions with D2O in the FT-ICR cell indicate substantial differences in H/D exchange rate and D2O accommodation for different ion structures and charge states. Most notably, the positively charged ions [H2(UO2)2Cit2(H)]+ and [(UO2)2(Cit)]+ accommodate two and three D2O molecules, respectively, which reflects well the structural differences, i.e., tighter uranyl-citrate coordination in the former ion than in the latter. The corresponding negatively charged ions accommodate zero or two D2O molecules, which can be rationalized using suggested solution phase structures

Water-Reflected 233U Uranyl Nitrate Solutions in Simple Geometry

International Nuclear Information System (INIS)

Elam, K.R.

2001-01-01

A number of critical experiments involving 233 U were performed in the Oak Ridge National Laboratory Building 9213 Critical Experiments Facility during the years 1952 and 1953. These experiments, reported in Reference 1, were directed toward determining bounding values for the minimum critical mass, minimum critical volume, and maximum safe pipe size of water-moderated solutions of 233 U. Additional information on the critical experiments was found in the experimental logbooks. Two experiments utilizing uranyl nitrate (UO 2 (NO 3 ) 2 ) solutions in simple geometry are evaluated in this report. Experiment 37 is in a 10.4-inch diameter sphere, and Experiment 39 is in a 10-inch diameter cylinder. The 233 U concentration ranges from 49 to 62 g 233 U/l. Both experiments were reflected by at least 6 inches of water in all directions. Paraffin-reflected uranyl nitrate experiments, also reported in Reference 1, are evaluated elsewhere. Experiments with smaller paraffin reflected 5-, 6-, and 7.5-inch diameter cylinders are evaluated in U233-SOL-THERM-004. Experiments with paraffin reflected 8-, 8.5-, 9-, 10-, and 12-inch diameter cylinders are evaluated in U233-SOL-THERM-002. Later experiments with highly-enriched 235 U uranyl fluoride solution in the same 10.4-inch diameter sphere are reported in HEU-SOL-THERM-010. Both experiments were judged acceptable for use as criticality-safety benchmark experiments

Vibrational spectra of monouranates and uranium hydroxides as reaction products of alkali with uranyl nitrate

International Nuclear Information System (INIS)

Komyak, A.I.; Umrejko, D.S.; Posledovich, M.R.

2013-01-01

Vibrational (IR absorption and Raman scattering) spectra for the reaction products of uranyl nitrate hexahydrate with NaOH and KOH have been studied. As a result of exchange reactions, the uranyl-ion coordinated nitrate groups are completely replaced by hydroxyl ions and various uranium and uranyl oxides or hydrates are formed. An analysis of the vibrations has been performed in terms of the frequencies of a free or coordinated nitrate group; comparison with the vibrations of the well-known uranium oxides and of the uranyl group UO 2 2+ has been carried out. Vibrational spectra of a free nitrate group are characterized by four vibrational frequencies 1050, 724, 850, and 1380 cm -1 , among which the frequencies at 724 and 1380 cm -1 are doubly degenerate and attributed to E’ symmetry of the point group D 3h . When this group is uranium coordinated, its symmetry level is lowered to C 2v , all vibrations of this group being active both in Raman and IR spectra. The doubly degenerate vibrations are exhibited as two bands and a frequency of the out-of-plane vibration is lowered to 815 cm -1 . (authors)

Reduced background autofluorescence for cell imaging using nanodiamonds and lanthanide chelates.

Science.gov (United States)

Cordina, Nicole M; Sayyadi, Nima; Parker, Lindsay M; Everest-Dass, Arun; Brown, Louise J; Packer, Nicolle H

2018-03-14

Bio-imaging is a key technique in tracking and monitoring important biological processes and fundamental biomolecular interactions, however the interference of background autofluorescence with targeted fluorophores is problematic for many bio-imaging applications. This study reports on two novel methods for reducing interference with cellular autofluorescence for bio-imaging. The first method uses fluorescent nanodiamonds (FNDs), containing nitrogen vacancy centers. FNDs emit at near-infrared wavelengths typically higher than most cellular autofluorescence; and when appropriately functionalized, can be used for background-free imaging of targeted biomolecules. The second method uses europium-chelating tags with long fluorescence lifetimes. These europium-chelating tags enhance background-free imaging due to the short fluorescent lifetimes of cellular autofluorescence. In this study, we used both methods to target E-selectin, a transmembrane glycoprotein that is activated by inflammation, to demonstrate background-free fluorescent staining in fixed endothelial cells. Our findings indicate that both FND and Europium based staining can improve fluorescent bio-imaging capabilities by reducing competition with cellular autofluorescence. 30 nm nanodiamonds coated with the E-selectin antibody was found to enable the most sensitive detective of E-selectin in inflamed cells, with a 40-fold increase in intensity detected.

Method of separation of uranium from contaminating ions in an aqueous feed liquid containing uranyl ions

International Nuclear Information System (INIS)

Sundar, P.S.; Elikan, L.; Lyon, W.L.

1975-01-01

A coupled cationic/anionic method for the separation of uranium from contaminated aqueous solutions which contain uranyl ions is proposed. The fluid is extracted using an organic solvent containing a reagent which, together with the uranyl ions, forms a soluble aggregate in that solvent. As an example, 0.1 - 1 Mol/l Di-2-ethyl-hexyl-phosphorous acid in kerosene is mentioned. The organic solvent is then treated with a sealing liquid (volume ratio 20 - 35). For separation, an aqueous carbonate solution or a sulfuric acid solution can be used; the most favorable pH-values and concentrations for both cases are mentioned. The U +4 -ion at the sulfuric acid separation is subsequently oxidized to the uranyl ion with air. In each case, an extraction with an amine follows; after that, the amine is separated using an ammonium-carbonate solution and the uranium aggregate is precipitated, for example as ammonium uranyl tricarbonate, and then further processed to uranium oxide. The solvents and fluids used are led back in closed circuit; a flow diagram is given. (UWI) [de

Uranyl(VI) luminescence spectroscopy at elevated temperatures

Energy Technology Data Exchange (ETDEWEB)

Steudtner, Robin; Franzen, Carola; Brendler, Vinzenz [Helmholtz-Zentrum Dresden-Rossendorf e.V., Dresden (Germany). Div. Surface Processes; Haubitz, Toni [Brandenburg Univ. of Technology, Cottbus-Senftenberg (Germany)

2016-07-01

We studied the influence of temperature and ionic strength on the luminescence characteristics (band position, decay time and intensity) of the free uranyl ion (UO{sub 2}{sup 2+}) in acidic aqueous solution. Under the chosen conditions an increasing temperature reduced both intensity and luminescence decay time of the UO{sub 2}{sup 2+} luminescence, but the individual U(VI) emission bands did not change.

Kinetic studies of uranyl ion adsorption on acrylonitrile (AN)/polyethylene glycol (PEG) interpenetrating networks (IPN)

International Nuclear Information System (INIS)

Aycik, G.A.; Gurellier, R.

2004-01-01

Full text: The kinetics of the adsorption of uranyl ions on amidoximated acrylonitrile (AN)/ polyethylene glycol (PEG) interpenetrating network (IPNs) from aqueous solutions was studied as a function of time and temperature. The IPNs were prepared by irradiation initiated gamma polymerisation using Co-60 gamma source. Adsorption capacities were performed for definite uranyl ion concentrations of 1x10 -2 M and at four different temperatures as 290K, 298K, 308K and 318K by gamma spectrometer. Adsorption time was increased from zero to 48 hours. The results indicate that adsorption capacity increases linearly with increasing temperature. Temperature and agitation hardly influence equilibrium and kinetics and decreasing of temperature results in a slightly greater time to reach equilibrium. The adsorption of uranyl ions has been studied in a multi step mechanism processes thus comparing chemical sorption and diffusion sorption processes. The experimental data was analysed using various kinetic models to determine the best-fit equation for the adsorption mechanisms. However, it was shown that all models, in general according to the reaction time and uranyl ion concentration in the solution, could describe the adsorption of uranyl ion onto amidoximated IPN, the adsorption kinetics was best described by zeroth order and intraparticle diffusion model whereas that of in increasing time by pseudo first and pseudo second order response respectively. External-intraparticle diffusion and zeroth order process in the IPN structure is proposed as a mass transfer mechanism and the results indicate a diffusion-controlled process. The Mean Activation Energy Of Uranyl Ions Adsorption Was Found As 4,1 Kj/Mole By Using Arrhenius Equation. The Rate Constant, The Equilibrium Adsorption Capacity And The Initial Adsorption Rate Were Calculated For All Models At Each Temperature. Kinetic Parameters Of All Models And The Normalized Standard Deviations Between The Measured And Predicted

Determination of free nitric acid in uranyl nitrate solution

International Nuclear Information System (INIS)

Mayankutty, P.C.; Ravi, S.; Nadkarni, M.N.

1981-01-01

Potentiometric titration of uranyl nitrate solution with sodium hydroxide exhibits two peaks. The first peak characterises the following reaction, UO 2 (C 2 O 4 )+NaOH Na[UO 2 (C 2 O 4 )(OH)]. This reaction, indicating the partial hydrolysis of uranyl oxalate complex, appears to be complete at pH9. If the titration is carried out to this end-point pH, the total alkali consumed can be equated to the sum of uranium content and the free acidity present in the sample volume. Based on this, a method was standardised to determine the free acidity in uranyl nitrate solution. The sample, taken in a solution of potassium oxalate previously adjusted to pH9, is titrated to this pH with standard sodium hydroxide. The free acidity in the sample can be computed by subtracting the alkali reacted with uranium from the total alkali consumed. Analyses of several synthetic samples containing uranium and nitric acid in a wide range of combinations indicate that the free acidity can be accurately determined by this method, if uranium concentration in the sample is known. The results are compared to those obtained by two other widely used methods, viz., (i) titration of pH7 in the presence of neutral potassium oxalate to suppress hydrolysis and (ii) separation of hydrolyzable ions on a cationic resin and alkali titration of the free acid released. The advantages of and the precision obtained with the present method over the above two methods are discussed. (author)

Comments on chelation therapy

International Nuclear Information System (INIS)

Wrenn, M.E.

1981-01-01

The primary purpose of actinide chelation is to decrease the risk from radiation-induced cancer. While occupational exposures in the past have mainly involved low specific activity 239 Pu, future exposures will increasingly involve high specific activity plutonium, americium, and curium - all of which clear more rapidly from the lung. This will tend to shift the cancer risk from lung to bone and liver. Although therapy with Ca- or Zn-DTPA rapidly removes 241 Am from the canine, the sub-human primate, and the human liver, improved methods for removal from bone and lung are needed. DTPA can remove 241 Am more easily from the growing skeleton of a child than from the mature skeleton of an adult. Investigators at Karlsruhe are developing chelation agents for oral administration and are investigating the reduction in local dose to bone resulting from chelation therapy

Electrochemical studies on the reduction of uranyl ions in nitric acid-hydrazine media at platinum electrode

International Nuclear Information System (INIS)

Mishra, Satyabrata; Sini, K.; Mallika, C.; Kamachi Mudali, U.; Jagadeeswara Rao, Ch.

2015-01-01

Production of uranous nitrate with good conversion efficiency is one of the major steps in the aqueous reprocessing of spent fuels of nuclear reactors, as U(IV) is used for the separation of Pu from U by the selective reduction of Pu(IV) into practically non-extractable Pu(III) in aqueous streams. Electro-reduction of uranyl ions has the advantage of not introducing corrosive chemicals into the process stream. High current efficiency with maximum conversion of U(VI) to U(IV) can be achieved in continuous as well as batch mode electro-reduction, if the process is voltage-controlled rather than current controlled. As potentiostatic studies reveal the mechanism of reduction of uranyl ions in potential controlled electrolysis, the reduction behavior of uranyl ions (UO 2 2+ ) in nitric acid and nitric acid-hydrazine media were investigated by Cyclic Voltammetric (CV) and Chronopotentiometric (CP) techniques using platinum working electrode at 298 K. Heterogeneous electron transfer rate constant (ks) for uranyl reduction was estimated at a very low concentration of nitric acid (0.05 M) using Klinger and Kochi equation. Values of the diffusion coefficients were determined as a function of acidity with and without hydrazine. Reduction of uranyl ions was found to be under kinetic as well as diffusion control when the concentration of nitric acid was 0.05 M and in the absence of hydrazine. However, as the acidity of the supporting electrolyte increased, the reduction was purely under kinetic control. (author)

Kinetic analysis of laser induced phosphorescence in uranyl phosphate for improved analytical measurements

International Nuclear Information System (INIS)

Bushaw, B.A.

1983-10-01

Pulsed dye-laser excitation with multichannel scaler photon counting is used to obtain time resolved emission spectra of uranyl ions in aqueous solution. Kinetic analysis of this data corrects for matrix quenching and temperature effects which reduce the quantum yield of the uranyl ion luminescence. The method gives accurate measurements without separative prechemistry or the use of internal standards. Detection limits of one part-per-trillion (pptr) have been demonstrated, and in samples with concentrations greater than 100 pptr, relative standard deviations of less than 3% are achieved routinely

First start-up of nuclear criticality safety experiment facility for uranyl nitrate solution

International Nuclear Information System (INIS)

Zhu Qingfu; Shi Yongqian; Shen Leisheng; Hu Dingsheng; Zhao Shouzhi; He Tao; Sun Zheng; Lin Shenghuo; Yao Shigui

2005-01-01

The uranyl nitrate solution experiment facility for the research on nuclear criticality safety is described. The nuclear fuel loading steps in the first start-up for water-reflected core are presented. During the experiments, the critical volume of uranyl nitrate solution was determined as 20479.62 mL with count rate inverse extrapolation method, reactivity interpolation method, and steady power method. By calculation, critical mass of 235 U was derived as 1579.184 g from experimental data. The worth of control rods was also calibrated in the first start-up of the facility. (authors)

DFT study of uranyl peroxo complexes with H2O, F-, OH-, CO3(2-), and NO3(-).

Science.gov (United States)

Odoh, Samuel O; Schreckenbach, Georg

2013-05-06

The structural and electronic properties of monoperoxo and diperoxo uranyl complexes with aquo, fluoride, hydroxo, carbonate, and nitrate ligands have been studied using scalar relativistic density functional theory (DFT). Only the complexes in which the peroxo ligands are coordinated to the uranyl moiety in a bidentate mode were considered. The calculated binding energies confirm that the affinity of the peroxo ligand for the uranyl group far exceeds that of the F(-), OH(-), CO3(2-), NO3(-), and H2O ligands. The formation of the monoperoxo complexes from UO2(H2O)5(2+) and HO2(-) were found to be exothermic in solution. In contrast, the formation of the monouranyl-diperoxo, UO2(O2)2X2(4-) or UO2(O2)2X(4-/3-) (where X is any of F(-), OH(-), CO3(2-), or NO3(-)), complexes were all found to be endothermic in aqueous solution. This suggests that the monoperoxo species are the terminal monouranyl peroxo complexes in solution, in agreement with recent experimental work. Overall, we find that the properties of the uranyl-peroxo complexes conform to well-known trends: the coordination of the peroxo ligand weakens the U-O(yl) bonds, stabilizes the σ(d) orbitals and causes a mixing between the uranyl π- and peroxo σ- and π-orbitals. The weakening of the U-O(yl) bonds upon peroxide coordination results in uranyl stretching vibrational frequencies that are much lower than those obtained after the coordination of carbonato or hydroxo ligands.

Crystal structure of the uranyl-oxide mineral rameauite

Czech Academy of Sciences Publication Activity Database

Plášil, Jakub; Škoda, R.; Čejka, J.; Bourgoin, V.; Boulliard, J.C.

2016-01-01

Roč. 28, č. 5 (2016), s. 959-967 ISSN 0935-1221 R&D Projects: GA MŠk LO1603 EU Projects: European Commission(XE) CZ.2.16/3.1.00/24510 Institutional support: RVO:68378271 Keywords : rameauite * uranyl-oxide hydroxy-hydrate * crystal structure * Raman spectrum Subject RIV: BM - Solid Matter Physics ; Magnetism Impact factor: 1.362, year: 2016

The bare uranyl(2+) ion, UO22+

International Nuclear Information System (INIS)

Cornehl, H.H.; Heinemann, C.; Marcalo, J.; Pires de Matos, A.; Schwarz, H.

1996-01-01

Ion-molecule reactions between U 2+ and oxygen donors or charge-stripping collisions between singly charged UO 2 2 ions and O 2 collision partners generate uranyl(2+) ions in the gas phase. These do not readily dissociate into singly charged fragments. The standard enthalpy of formation for UO 2 2+ is estimated to be 371±60 kcal mol -1 , in accord with the results of ab initio calculations. (orig.)

Photophysics of the excited uranyl ion in aqueous solutions

International Nuclear Information System (INIS)

Formosinho, S.J.; Miguel, M. da G.M.

1985-01-01

The effect of the micelles of Triton X-100 on the biexponential decay of (UO 2 2+ )* has been investigated. Data are analysed in terms of a reversible crossing mechanism for the decay. Azulene fluorescence quenching and 13 C n.m.r. studies strongly suggest that uranyl ions are able to penetrate deep inside the micelle core. Micelle quenching for the reversible decay of (UO 2 2+ )* occurs in the interior (ksub(q) = 3 x 10 10 dm 3 mol -1 s -1 ) and at the surface (Ksub(q) = 1.5 x 10 9 mol -1 dm 3 s -1 ) of the micelles. The latter process has a rate virtually identical to that for the free surfactant molecules. Penetration of (UO 2 2+ )* inside the non-polar regions of the micelle core increases solvent exchange rates by ca. two orders of magnitude. Uranyl-ion excimers are formed in occupied micelles. The quenching processes decrease strongly for these species because excimers do not penetrate the micelles. (author)

The biodistribution study of 99mTc labelled anti-CEA monoclonal antibody in tumor bearing nude mice

International Nuclear Information System (INIS)

Lou Zongxin

1992-01-01

The author report the optimal condition of 99m Tc labelling with anti-CEA monoclonal antibody using chelating of 99m Tc with dimethylformamide. The labelling rate of this method is 60%-80%, the radiochemical purity of labelling antibody over 90% and maintain its better immuno activity. The biodistribution of the tumor bearing nude mice demonstrates that as compared with the control group, 24 hours after the intraperitoneal injection the injected labelled antibody has its specific concentration in tumor tissue

Colorimetric peroxidase mimetic assay for uranyl detection in sea water

KAUST Repository

Zhang, Dingyuan; Chen, Zhuo; Omar, Haneen; Deng, Lin; Khashab, Niveen M.

2015-01-01

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

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

[UO{sub 2}Cl{sub 2}(phen){sub 2}], a simple uranium(VI) compound with a significantly bent uranyl unit (phen=1,10-phenanthroline)

Energy Technology Data Exchange (ETDEWEB)

Schoene, Sebastian; Radoske, Thomas; Maerz, Juliane; Stumpf, Thorsten; Patzschke, Michael; Ikeda-Ohno, Atsushi [Helmholtz-Zentrum Dresden-Rossendorf (HZDR), Institute of Resource Ecology, Dresden (Germany)

2017-10-04

A simple synthesis based on UO{sub 2}Cl{sub 2}.n H{sub 2}O and 1,10-phenanthroline (phen) resulted in the formation of a new uranyl(VI) complex [UO{sub 2}Cl{sub 2}(phen){sub 2}] (1), revealing a unique dodecadeltahedron coordination geometry around the uranium center with significant bending of the robust linear arrangement of the uranyl (O-U-O) unit. Quantum chemical calculations on complex 1 indicated that the weak but distinct interactions between the uranyl oxygens and the adjacent hydrogens of phen molecules play an important role in forming the dodecadeltahedron geometry that fits to the crystal structure of 1, resulting in the bending the uranyl unit. The uranyl oxygens in 1 are anticipated to be activated as compared with those in other linear uranyl(VI) compounds. (copyright 2017 Wiley-VCH Verlag GmbH and Co. KGaA, Weinheim)

Determination of the extractive capacity of para-tert butyl calix[8]arene octa-phosphinoylated towards uranyl ions from an aqueous-acidic-salty medium

International Nuclear Information System (INIS)

Serrano V, E. C.

2011-01-01

The extraction properties of octa-phosphinoylated para-tert butyl calix[8]arene (prepared in the laboratory) in chloroform towards uranyl ions from an aqueous-acidic-salty medium (HNO 3 -3.5 NaNO 3 ) containing uranyl nitrate salt, was investigated. Two spectroscopic techniques UV/Vis and Luminescence were used for this study. The latter permitted analyze the fluorescence from the uranyl ions influenced by the surrounding medium. Both permitted to learn about the power of this calixarene as extractant towards the mentioned ions. Its extraction ability or capability using this calixarene at 5.91 x 10 -4 M towards the uranyl ions was 400% as determined by UV/Vis while fluorescence revealed 100% of uranyl ion extraction. A closed analysis of the results obtained by using these techniques revealed that the stoichiometry of the main extracted species was 1calixarene:2 uranyl ions. The loading capacity of the calixarene ligand towards the uranyl ions was also investigated using both techniques. UV/Vis resulted to be inadequate for quantifying exactly the loading capacity of the calixarene whereas luminescence was excellent indeed, using a 5.91 x 10 -4 M calixarene concentration, its loading capacity was 0.157 M of free uranyl ions from 0.161 M of uranyl ions present in the aqueous-acidic-salty medium. The extracts from the ability and capacity studies were concentrated to dryness, purified and the dried extracts were analyzed by infrared and neutron activation analysis. By these techniques it was demonstrated that during the extraction of the uranyl ions by the calixarene ligand they form thermodynamically and kinetically stable complexes, since in the solid state, the 1:2, calixarene; uranyl ions stoichiometry was kept with the minimum formula: (UO 2 ) 2 B 8 bL 8 (NO 3 ) 4 (H 2 O) 4 CHCl 3 (CH 3 OH) 3 the methanol molecules come from its purification. It is proposed that B 8 bL 8 calixarene in chloroform medium is a good extractant for the treatment of nuclear wastes or

An unprecedented two-fold nested super-polyrotaxane: sulfate-directed hierarchical polythreading assembly of uranyl polyrotaxane moieties

Energy Technology Data Exchange (ETDEWEB)

Mei, Lei; Wu, Qun-yan; Yuan, Li-yong; Wang, Lin; An, Shu-wen; Xie, Zhen-ni; Hu, Kong-qiu; Shi, Wei-qun [Laboratory of Nuclear Energy Chemistry and Key Laboratory for Biomedical Effects of Nanomaterials and Nanosafety, Institute of High Energy Physics, Chinese Academy of Sciences, Beijing (China); Chai, Zhi-fang [Laboratory of Nuclear Energy Chemistry and Key Laboratory for Biomedical Effects of Nanomaterials and Nanosafety, Institute of High Energy Physics, Chinese Academy of Sciences, Beijing (China); School of Radiological and Interdisciplinary Sciences and Collaborative Innovation Center of Radiation Medicine of Jiangsu Higher Education Institutions, Soochow University, Suzhou (China); Burns, Peter C. [Department of Chemistry and Biochemistry, University of Notre Dame, IN (United States)

2016-08-01

The hierarchical assembly of well-organized submoieties could lead to more complicated superstructures with intriguing properties. We describe herein an unprecedented polyrotaxane polythreading framework containing a two-fold nested super-polyrotaxane substructure, which was synthesized through a uranyl-directed hierarchical polythreading assembly of one-dimensional polyrotaxane chains and two-dimensional polyrotaxane networks. This special assembly mode actually affords a new way of supramolecular chemistry instead of covalently linked bulky stoppers to construct stable interlocked rotaxane moieties. An investigation of the synthesis condition shows that sulfate can assume a vital role in mediating the formation of different uranyl species, especially the unique trinuclear uranyl moiety [(UO{sub 2}){sub 3}O(OH){sub 2}]{sup 2+}, involving a notable bent [O=U=O] bond with a bond angle of 172.0(9) . Detailed analysis of the coordination features, the thermal stability as well as a fluorescence, and electrochemical characterization demonstrate that the uniqueness of this super-polyrotaxane structure is mainly closely related to the trinuclear uranyl moiety, which is confirmed by quantum chemical calculations. (copyright 2016 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim)

Chelation in root canal therapy reconsidered.

Science.gov (United States)

Zehnder, Matthias; Schmidlin, Patrick; Sener, Beatrice; Waltimo, Tuomas

2005-11-01

The aim of this study was to assess interactions of EDTA and citric acid (CA) with sodium hypochlorite (NaOCl), the indispensable endodontic irrigant. Other chelators were simultaneously evaluated as possible alternatives: sodium triphosphate (STP), amino tris methylenephosphonic acid (ATMA), and 1- hydroxyethylidene-1, 1-bisphosphonate (HEBP). Available chlorine was titrated in chelator-NaOCl solutions. All chelators other than HEBP and STP caused an almost complete, immediate loss of available chlorine in solution. Atomic absorbtion spectrometry and SEM evaluation of root canal walls of instrumented teeth indicated that NaOCl had no negative effect on calcium-complexing ability of chelators. STP was too weak a complexing agent to warrant further studies. Finally, CA-, EDTA-, and HEBP-NaOCl mixtures were evaluated for their antimicrobial capacity. Again, EDTA and CA negatively interfered with NaOCl, while HEBP did not.

Comparing uranyl sorption complexes on soil and reference clays

International Nuclear Information System (INIS)

Chisholm-Brause, C.J.; Berg, J.M.; Conradson, S.D.; Morris, D.E.; McKinley, J.P.; Zachara, J.M.

1993-01-01

Clay minerals and other components in natural soils may play a key role in limiting the mobility of uranium in the environment through the formation of sorption complexes. Reference clays are frequently used as models to study sorption processes because they have well-known chemical and physical properties, but they may differ chemically and morphologically from clays derived from natural soils. Therefore, inferences based on reference clay data have been questioned. The authors have used luminescence and x-ray absorption spectroscopies to characterize the sorption complexes of aqueous uranyl (UO 2 2+ ) species on two soil smectites from the Kenoma and Ringold formations, and compared these results to those obtained on reference smectite clays. The pH dependence of uptake suggests that the ratio of sorption on amphoteric edge sites is greater for the soil smectites than for reference clays such as Wyoming montmorillonite (SWy-1). The luminescence spectra for uranyl sorbed to the soil clays are very similar to those for uranyl sorbed principally to the edge sites of SWy-1. This observation supports the solution data suggesting that adsorption to amphoteric sites is a more important mechanism for soil clays. However, the spectral data indicate that the sorption complexes on natural and reference clays are quite similar. Furthermore, as with the reference clays, the authors have found that the chemistry of the solution plays a greater role in defining the sorption complex than does the clay matrix. Thus, if differences in surface properties are adequately taken into account, the reference clays may serve as useful analogs for soil clays in investigations of metal-ion sorption

Biological behaviour of some 67Ga and 64Cu chelates

International Nuclear Information System (INIS)

Leonovicova, T.; Angelis, B.; Cifka, J.; Cifkova, I.

1984-01-01

Chelates of 67 Ga and 64 Cu with iminodiacetic acid (IDA) and its two phenyl derivatives as well as with nitrilotriacetic acid (NTA) and benzylnitrilotriacetic acid (BNTA) were prepared. All the chelates were found to be negatively charged. A study of the biological distribution of these chelates in rats during time intervals of 3 to 180 min showed that the chelate of 67 Ga with IDA substituted at a phenyl by a hydrophobic substituent is excreted by the kidneys into the urine at a much higher rate than the IDA chelate of 67 Ga. The excretion of NTA and BNTA chelates of 67 Ga is the opposite. Blood clearance of 64 Cu chelates is more rapid than that of 67 Ga chelates. Chelates of 64 Cu accumulate in the liver and with the bile are slowly excreted into the intestines, urinary excretion is negligible. (author)

Crystal field influence on vibration spectra: anhydrous uranyl chloride and dihydroxodiuranyl chloride tetrahydrate

International Nuclear Information System (INIS)

Perrin, Andre; Caillet, Paul

1976-01-01

Vibrational spectra of anhydrous uranyl chloride UO 2 Cl 2 and so called basic uranyl chloride: dihydroxodiuranyl chloride tetrahydrate /UO 2 (OH) 2 UO 2 /Cl 2 (H 2 O) 4 are reported. Factor group method analysis leads for the first time to complete and comprehensive interpretation of their spectra. Two extreme examples of crystal field influence on vibrational spectra are pointed out: for UO 2 Cl 2 , one is unable to explain spectra without taking into account all the elements of primitive crystalline cell, whilst for dihydroxodiuranyl dichloride tetrahydrate the crystal packing has very little effect on vibrational spectra [fr

Controlled deprotection and reorganization of uranyl oxo groups in a binuclear macrocyclic environment

International Nuclear Information System (INIS)

Jones, Guy M.; Arnold, Polly L.; Love, Jason B.

2012-01-01

Switching on uranium(V) reactivity: The silylated uranium(V) dioxo complex [(Me_3SiOUO)_2(L)_2] (A) is inert to oxidation, but after two-electron reduction to [(Me_3SiOUO)_2(L)]"2"- (1), it can be desilylated to form [OU(μ-O)_2UO(L)_2]"2"- (2) with reinstated uranyl character. Removal of the silyl group uncovers new redox and oxo rearrangement chemistry for uranium, thus reforming the uranyl motif and involving the U"V"I"/"V couple in dioxygen reduction. (Copyright copyright 2012 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim)

Determination of uranium in uranyl nitrate solutions of nuclear grade quality - Gravimetric method

International Nuclear Information System (INIS)

1990-01-01

This international Standard specifies a precise and accurate gravimetric method for determining the uranium content in uranyl nitrate product solutions of nuclear grade quality at concentrations above 100 g/l of uranium. Non-volatile impurities influence the accuracy of the method. Uranyl nitrate is converted into uranium octoxide (U 3 O 8 ) by ignition in air to constant mass at 900 deg. C ± 10 deg. C. Calculation of the uranium content in the sample using a gravimetric conversion factor which depends on the isotopic composition of the uranium. The isotopic composition is determined by mass spectrometry

Interaction of aluminium(3) with uranyl ions in the course of joint hydrolysis

International Nuclear Information System (INIS)

Yusov, A.B.; Budantseva, N.A.; Fedoseev, A.M.; Astafurova, L.N.

2001-01-01

By means of spectrophotometry, luminescence and IR-spectroscopy one studied interaction of uranyl ions with Al 3+ ions in solutions at pH≥2 and in precipitates at pH≥5. It is shown that within 3-4 pH range the uranyl hydrolyzed forms interact with these of aluminium. Mixed hydroxoaquacomplexes are likely to be formed in solution with U:Al = 1:1 molar ratio. Large-size mixed polymers may be formed with pH increase. Varying of precipitation pH from 5 up to 14 does not minimize the importance of the oligomer mixed compounds for precipitation formation [ru

Pharmacokinetics of 111In-labeled anti-p97 monoclonal antibody in patients with metastatic malignant melanoma

International Nuclear Information System (INIS)

Rosenblum, M.G.; Murray, J.L.; Haynie, T.P.; Glenn, H.J.; Jahns, M.F.; Benjamin, R.S.; Frincke, J.M.; Carlo, D.J.; Hersh, E.M.

1985-01-01

Twenty-eight patients with metastatic malignant melanoma received anti-p97 murine monoclonal antibody (96.5) infused over 2 h at doses between 1 and 20 mg coupled to either 2.5 or 5.0 mCi of 111 In by the bifunctional chelating agent diethyltriaminepentaacetic acid. Clearance of 111 In from plasma closely fit an open, one-compartment mathematical model (r2 greater than 0.90). The overall half-life of 111 In plasma was approximately 31 h and did not appear to be dependent on the total dose of antibody administered. The apparent volume of distribution of the 111 In label approximated the total blood volume (7.8 +/- 0.7 liters) at the 1-mg dose and decreased to 3.0 +/- 0.14 liters at the 20-mg dose, suggesting saturation of antigenic or other extravascular binding sites at higher antibody doses. The clearance of the murine monoclonal antibody itself from plasma was measured by an enzyme-linked immunosorbent assay. The pharmacokinetics for the murine antibody in plasma also fit an open, one-compartment mathematical model. All pharmacokinetic parameters for unlabeled antibody closely paralleled those found for 111 In-labeled antibody pharmacokinetics. This suggests that the 111 In radiolabel remains complexed to the monoclonal antibody after in vivo administration. The cumulative urinary excretion of the 111 In label over 48 h was between 12 and 23% of the total administered dose and is assumed to represent 111 In-labeled chelate complex unattached to antibody. Analysis of the 111 In label in spleen, liver, heart, and kidney showed that the concentration of label in liver tissue was reduced with increasing antibody doses and coincided with changes in the apparent volume of distribution

Effect of uranyl nitrate and free acid concentration in feed solution of gelation on UO2 kernel quality

International Nuclear Information System (INIS)

Masduki, B.; Wardaya; Widarmoko, A.

1996-01-01

An investigation on the effect of uranium and free nitric acid concentration of uranyl nitrate as feed of gelation process on quality of UO 2 kernel was done.The investigation is to look for some concentration of uranyl nitrate solutions those are optimum as feed for preparation of gelled UO 3 . Uranyl nitrate solution of various concentration of uranium (450; 500; 550; 600; 650; 700 g/l) and free nitric acid of (0.9; 1.0; 1.1 N) was made into feed solutions by adding urea and HMTA with mole ratio of urea/uranium and HMTA/uranium 2.1 and 2.0. The feed solutions were changed into spherical gelled UO 3 by dropping was done to get the optimum concentrations of uranyl nitrate solutions. The gelled UO 3 was soaked and washed with 2.5% ammonia solution for 17 hours, dried at 70 o C, calcined at 350 o C for 3 hours then reduced at 850 o C for 3 hours. At every step of the steps process the colour and percentage of well product of gelled UO 3 were noticed. The density and O/U ratio of end product (UO 2 kernel) was determined, the percentage of well product of all steps process was also determined. The three factor were used to chose the optimum concentration of uranyl nitrate solution. From this investigation it was concluded that the optimum concentration of uranyl nitrate was 600 g/l uranium with free nitric acid 0,9 - 1,0 N, the percentage of well product was 97% density of 6.12 - 4.8 g/cc and O/U ratio of 2.15 - 2.06. (author)

Solvent extraction of uranyl nitrate (1962); Extraction du nitrate d'uranyle par solvant (1962)

Energy Technology Data Exchange (ETDEWEB)

Talmont, X; Regnaut, P [Commissariat a l' Energie Atomique, Fontenay-aux-Roses (France). Centre d' Etudes Nucleaires; Durandet, J; Renault, Ph; Gladel, Y L [Institut Francais du Petrole (IFP), Dept. de Physico-Chimie Appliquee, 92 - Rueil-Malmaison (France)

1962-07-01

The transfer of uranyl nitrate from an aqueous acid phase into a solvent (dilute tributylphosphate) is attended by nitric acid transfer. In these conditions, equilibrium data cannot be represented by a plane curve, which complicates the determination of the efficiency of the extractor used, i.e. the calculation of either the number of theoretical plates or the number of transfer units equivalent to the apparatus. The authors are presenting a simple method for estimating the efficiency of a column, based upon either uranium or acid transfer. This method can be used when the profile of uranium and acid concentrations in a phase circulating in the equipment bas been previously determined. On another hand, it enables to study the variation of local efficiency, i.e. the efficiency of different sections of the column. (authors) [French] Le transfert du nitrate d'uranyle d'une phase aqueuse acide dans un solvant (phosphate de tributyle dilue) s'accompagne d'un transfert d'acide nitrique. Dans ces conditions, les donnees d'equilibre ne sont pas representees par une courbe plane, ce qui complique la determination de l'efficacite de l'extracteur utilise, c'est-a-dire le calcul, soit du nombre d'etages theoriques, soit du nombre d'unites de transfert auquel l'appareil est equivalent. Les auteurs presentent une methode simple d'evaluation de l'efficacite d'une colonne basee, soit sur le transfert d'uranium, soit sur celui d'acide. Cette methode est utilisable lorsqu'en a determine au prealable le profil des concentrations en uranium et en acide d'une phase circulant dans l'appareil. Elle permet, d'autre part, d'etudier la variation de l'efficacite locale, c'est-a-dire l'efficacite de differentes sections de la colonne. (auteurs)

Uranyl citrate dimers as guests in a copper-bipyridine framework: a novel hetero-metallic inorganic-organic hybrid compound

International Nuclear Information System (INIS)

Thuery, P.

2007-01-01

Reaction of uranyl nitrate with citric acid (H 4 cit) in the presence of copper(II) bis(tri-fluoro-methane-sulfonate) and 4,4'-bipyridine (bipy) under hydrothermal conditions gave the mixed complex[Cu(bipy) 2 (H 2 O) 2 ][UO 2 (Hcit)(H 2 O)] 2 .5H 2 O, in which di-anionic uranyl citrate dimers are incorporated in the interlayer spaces of the [Cu(bipy) 2 (H 2 O) 2 ] n 2n+ square grid assemblage. An extended hydrogen bonding network links the uranyl complex units together and also to the grid framework, resulting in the formation of a 3-D assemblage held by weak interactions. (author)

Formation of the second organic phase during uranyl nitrate extraction from aqueous solution by 30% tributylphosphate solution in paraffin

International Nuclear Information System (INIS)

Yhrkin, V.G.

1996-01-01

For extraction systems aqueous solution of uranyl nitrate-30% solution of tributylphosphate in individual paraffins from C 13 to C 17 the influence of the second organic phase of uranyl nitrate concentration in aqueous and organic phases, the length of hydrocarbon chain of paraffin hydrocarbon and temperature from 25 to 50 deg C on formation conditions has been defected. A special method of achieving the conditions of organic phase stratification from three-phase region, involving definition of equilibrium phases composition by density and refractive index, has been elaborated for more precise definition of organic phase homogeneity region. It has been revealed that without addition of nitric acid to uranyl nitrate solution the organic phase homogeneity limits can be achieved solely on paraffins C 15 , C 16 and C 17 and only under conditions similar to equeous phase saturation in terms of uranyl nitrate. 16 refs., 2 figs

Hydrothermal synthesis of uranyl squarates and squarate-oxalates: hydrolysis trends and in situ oxalate formation.

Science.gov (United States)

Rowland, Clare E; Cahill, Christopher L

2010-07-19

We report the synthesis of two uranyl squarates and two mixed-ligand uranyl squarate-oxalates from aqueous solutions under hydrothermal conditions. These products exhibit a range of uranyl building units from squarates with monomers in (UO(2))(2)(C(4)O(4))(5).6NH(4).4H(2)O (1; a = 16.731(17) A, b = 7.280(8) A, c = 15.872(16) A, beta = 113.294(16) degrees , monoclinic, P2(1)/c) and chains in (UO(2))(2)(OH)(2)(H(2)O)(2)(C(4)O(4)) (2; a = 12.909(5) A, b = 8.400(3) A, c = 10.322(4) A, beta = 100.056(7) degrees , monoclinic, C2/c) to two squarate-oxalate polymorphs with dimers in (UO(2))(2)(OH)(C(4)O(4))(C(2)O(4)).NH(4).H(2)O (3; a = 9.0601(7) A, b = 15.7299(12) A, c = 10.5108(8) A, beta = 106.394(1) degrees , monoclinic, P2(1)/n; and 4; a = 8.4469(6) A, b = 7.7589(5) A, c = 10.5257(7) A, beta = 105.696(1) degrees , monoclinic, P2(1)/m). The dominance at low pH of monomeric species and the increasing occurrence of oligomeric species with increasing pH suggests that uranyl hydrolysis, mUO(2)(2+) + nH(2)O right harpoon over left harpoon [(UO(2))(m)(OH)(n)](2m-n) + nH(+), has a significant role in the identity of the inorganic building unit. Additional factors that influence product assembly include in situ hydrolysis of squaric acid to oxalic acid, dynamic metal to ligand concentration, and additional binding modes resulting from the introduction of oxalate anions. These points and the effects of uranyl hydrolysis with changing pH are discussed in the context of the compounds presented herein.

Recovery of uranium from uranyl nitrate raffinate. Contributed Paper PE-06

International Nuclear Information System (INIS)

Anilkumar Reddy, A.M.; Shiva Kumar, M.; Varadan, K.M.K.; Babaji, P.; Sairam, S. Sheela; Saibaba, N.

2014-01-01

At New Uranium Oxide Fuel Plant, NUOFP(O) of Nuclear Fuel Complex (NFC), the Uranyl Nitrate Raffinate (UNR) generated during solvent extraction process is washed with Treated Lean Solvent(TLS) to recover residual U. Earlier this UNR consisting of 0.5-1 gm/l and 2.5 FA was neutralised with vapour ammonia. The slurry was then filtered over pre coat drum filter and the resultant Uranyl Nitrate Raffinate cake (UNRC) was stored in polyethylene lined MS drums. The valuable U was thus being locked up in UNRC. Also, the storage of UNRC drums required lot of floor space which have to be repacked frequently to contain the radioactivity. Hence the need has come to avoid the generation of UNRC and the recovery of U from the already generated UNRC. The generation of UNRC was avoided by developing alternate process of UNR treatment with Treated Lean Solvent for the removal of residual U and the resulting Acidic Raffinate Slurry (ARS) is disposed. The Uranium recovery from UNRC is done by dissolving the cake in Uranyl Nitrate Raffinate solution to leach the hexavalent Uranium by utilizing the free acidity in UNR. The leaching time is about six hours and the uranium forms uranyl nitrate. The resulting leach solutions are relatively dilute but complex acidic nitrate solutions containing wide variety of ions. Metallic ions commonly present include uranium, iron, magnesium, aluminium, sodium, calcium etc. The uranium concentration is normally 1-1.5 g/L. This uranium is separated by solvent extraction. The active agent in solvent extraction is Tri Butyl Phosphate in kerosene that can selectively extract uranium into an organic complex which is insoluble in aqueous. The organic used for extraction is Treated Lean Solvent in the quality of freshly prepared solvent and the resulting Acidic Raffinate Slurry is disposed by sale. The leaching of Uranium from UNRC was done in plant scale and about 1200 kgs of UNRC was successfully processed in trial batch. The paper deals with details of

Extraction of rare earth metals (3) from aqueous solutions containing thorium and uranyl nitrates

International Nuclear Information System (INIS)

Pyartman, A.K.; Kopyrin, A.A.; Berinskij, A.E.; Keskinov, V.A.

2000-01-01

Isotherms of extraction of rare earth metals (3) from aqueous solutions containing thorium and uranyl nitrates by solutions of tributylphosphate (TBP) and diisooctylmethylphosphonate (DIOMP) in kerosene at 298.15 Deg C and pH 1 are presented. Equations for description of interphase distribution of components of the systems considered are suggested. These equations describe distribution of components adequately in the systems of thorium nitrate (uranyl nitrate) - rare earth nitrates - (TBP, DIOMP) in the case of wide variation of phase compositions. Dependences of separation factors on composition of aqueous phase are considered [ru

Chelate-assisted phytoextraction of lead from contaminated soils

Energy Technology Data Exchange (ETDEWEB)

Cooper, E.M.; Sims, J.T.; Cunningham, S.D.; Huang, J.W.; Berti, W.R.

1999-12-01

Phytoextraction, a remediation strategy for lead (Pb)-contaminated soils that removes soil Pb through plant uptake and harvest, may be enhanced by use of synthetic chelates. The authors evaluated Pb desorption from four contaminated soils by seven chelates (CDTA, DTPA, EDDHA, EFTA, HEDTA, HEIDA, and NTA) at three rates. The three most effective chelates (CDTA, DTPA, and HEDTA) were used in greenhouse studies with an uncontaminated soil and a Pb-contaminated soil to determine the effect of chelate type and rate on growth, Pb uptake, and plant elemental composition. Lead desorption varied with chelate and soil and increased with chelate rate, averaging 948 mg Pb kg{sup {minus}1} at the 20 mmol kg{sup {minus}1} rate vs. 28 mg Pb kg{sup {minus}1} by the control. The general ranking of chelate effectiveness, based on total Pb desorbed, was HEDTA > CDTA > DTPA > EGTA > HEIDA > EDDHA {approximately} NTA. Plant uptake of Pb from the contaminated soil was enhanced by CDTA, DTPA, and HEDTA, but with even the most effective treatment (corn, high CDTA rate), the amount of Pb extracted by plants was rather low. Lead extractable by the Toxicity Characteristic Leaching Procedure (TCLP) was increased from 9 mg L{sup {minus}1} in the control to from 47 to 174 mg L{sup {minus}1} in soils treated with 20 mmol kg{sup {minus}1} CDTA or DTPA and chelates generally caused a shift in Pb from resistant to more soluble chemical fractions.

Critical experiments on low enriched uranyl nitrate solution with STACY

International Nuclear Information System (INIS)

Miyoshi, Yoshinori

1996-01-01

As the STACY started steady operations, systematic criticality data on low enriched uranyl nitrate solution system could be accumulated. Main experimental parameters for the cylindrical tank of 60 cm in diameter were uranium concentration and the reflector condition. Basic data on a simple geometry will be helpful for the validation of the standard criticality safety codes, and for evaluating the safety margin included in the criticality designs. Experiments on the reactivity effects of structural materials such as borated concrete and polyethylene are on schedule next year as the second series of experiments using 10 wt% enriched uranyl solution. Furthermore, neutron interacting experiments with two slab tanks will be performed to investigate the fundamental properties of neutron interaction effects between core tanks. These data will be useful for making more reasonable calculation models and for evaluating the safety margin in the criticality designs for the multiple unit system. (J.P.N.)

Criticality parameters for uranyl nitrate or plutonium nitrate systems in tributyl phosphate/kerosine and water

International Nuclear Information System (INIS)

Weber, W.

1985-01-01

This report presents the calculated values of smallest critical masses and volumina and neutron physical parameters for uranyl nitrate (3, 4, 5% U-235) or plutonium nitrate (5% Pu-240), each in a 30 per cent solution of tributyl phosphate (TBP)/kerosine. For the corresponding nitrate-water solutions, newly calculated results are presented together with a revised solution density model. A comparison of the data shows to what extent the criticality of nitrate-TBP/kerosine systems can be assessed on the basis of nitrate-water parameters, revealing that such data can be applied to uranyl nitrate/water systems, taking into account that the smallest critical mass of uranyl nitrate-TBP/kerosine systems, up to a 5 p.c. U-235 enrichment, is by 4.5 p.c. at the most smaller than that of UNH-water solutions. Plutonium nitrate (5% Pu-240) in the TBP/kerosine solution will have a smallest critical mass of up to 7 p.c. smaller, as compared with the water data. The suitability of the computing methods and cross-sections used is verified by recalculating experiments carried out to determine the lowest critical enrichment of uranyl nitrate. The calculated results are well in agreement with experimental data. The lowest critical enrichment is calculated to be 2.10 p.c. in the isotope U-235. (orig.) [de

Series of mixed uranyl-lanthanide (Ce, Nd) organic coordination polymers with aromatic polycarboxylates linkers.

Science.gov (United States)

Mihalcea, Ionut; Volkringer, Christophe; Henry, Natacha; Loiseau, Thierry

2012-09-17

Three series of mixed uranyl-lanthanide (Ce or Nd) carboxylate coordination polymers have been successfully synthesized by means of a hydrothermal route using either conventional or microwave heating methods. These compounds have been prepared from mixtures of uranyl nitrate, lanthanide nitrate together with phthalic acid (1,2), pyromellitic acid (3,4), or mellitic acid (5,6) in aqueous solution. The X-ray diffraction (XRD) single-crystal revealed that the phthalate complex (UO(2))(4)O(2)Ln(H(2)O)(7)(1,2-bdc)(4)·NH(4)·xH(2)O (Ln = Ce(1), Nd(2); x = 1 for 1, x = 0 for 2), is based on the connection of tetranuclear uranyl-centered building blocks linked to discrete monomeric units LnO(2)(H(2)O)(7) via the organic species to generate infinite chains, intercalated by free ammonium cations. The pyromellitate phase (UO(2))(3)Ln(2)(H(2)O)(12)(btec)(3)·5H(2)O (Ce(3), Nd(4)) contains layers of monomeric uranyl-centered hexagonal and pentagonal bipyramids linked via the carboxylate arms of the organic molecules. The three-dimensionality of the structure is ensured by the connection of remaining free carboxylate groups with isolated monomeric units LnO(2)(H(2)O)(7). The network of the third series (UO(2))(2)(OH)Ln(H(2)O)(7)(mel)·5H(2)O (Ce(5), Nd(6)) is built up from dinuclear uranyl units forming layers through connection with the mellitate ligands, which are further linked to each other through discrete monomers LnO(3)(H(2)O)(6). The thermal decomposition of the various coordination complexes led to the formation of mixed uranium-lanthanide oxide, with the fluorite-type structure at 1500 °C (for 1, 2) or 1400 °C for 3-6. Expected U/Ln ratio from the crystal structures were observed for compounds 1-6.

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)

[Susceptibility of enterococci to natural and synthetic iron chelators].

Science.gov (United States)

Lisiecki, Paweł; Mikucki, Jerzy

2002-01-01

A total of 79 strains of enterococci belonging to 10 species were tested for susceptibility to natural and synthetic iron chelators. All strains produced siderophores. These enterococci were susceptible to three synthetic iron chelators only: 8-hydroxyquinoline, disodium versenate (EDTA) and o-phenanthroline. They were resistant to all other synthetic chelators: ethylenediamine-di(o-hydroxyphenylacetic acid) (EDDHA), nitrilotriacetate, 2,2'-bipiridyl, salicylic acid, 8-hydroxy-5-sulphonic acid and to all natural chelators: ovotransferrine, human apotransferrine, horse apoferritine, desferrioxamine B, ferrichrome and rhodotorulic acid. The relations between susceptibility/resistance, iron assimilation and structure and stability constants of iron chelators were discussed.

Thermal decomposition kinetics of ammonium uranyl carbonate

International Nuclear Information System (INIS)

Kim, E.H.; Park, J.J.; Park, J.H.; Chang, I.S.; Choi, C.S.; Kim, S.D.

1994-01-01

The thermal decomposition kinetics of AUC [ammonium uranyl carbonate; (NH 4 ) 4 UO 2 (CO 3 ) 3 [ in an isothermal thermogravimetric (TG) reactor under N 2 atmosphere has been determined. The kinetic data can be represented by the two-dimensional nucleation and growth model. The reaction rate increases and activation energy decreases with increasing particle size and precipitation time which appears in the particle size larger than 30 μm in the mechano-chemical phenomena. (orig.)

Mixed ligand chelates of rare earths in aqueous solution

International Nuclear Information System (INIS)

Lakhani, S.U.; Thakur, G.S.; Sangal, S.P.

1981-01-01

Mixed ligand chelates of the 1:1 trivalent lanthanoids-EDTA, HEDTA and NTA chelates-1, 2-Dihydroxybenzene (Pyrocatechol) have been investigated at 35degC and 0.2 M ionic strength maintained by NaC10 4 . The formation of mixed ligand chelates has been found in all cases. The formation of mixed ligand chelates with EDTA shows the coordination number of lanthanoids to be eight, while the mixed ligand chelates with HEDTA and NTA shows the coordination number to be seven and six respectively. The stability constants of mixed ligand chelates are smaller than the binary complexes. The order of stability constants with respect to primary ligands follows the order NTA>HEDTA>EDTA. With respect to metal ions the stability constants increases with the decrease in ionic radii such as Gd< Er< Yb. (author)

Derivation of an empirical formula for determining water content of mixed uranyl nitrate-thorium nitrate solutions

International Nuclear Information System (INIS)

Min, Duck Kee; Choi, Byung Il; Ro, Seung Gy; Eom, Tae Yoon; Kim, Zong Goo

1986-01-01

Densities of a large number of mixed uranyl nitrate-thorium nitrate solutions were measured with pycnometer. By the least squares analysis of the experimental result, an empirical formula for determining water content of mixed uranyl nitrate-thorium nitrate solutions as functions of uranium concentration, thorium concentration and nitric acid normality is derived; W=1.0-0.3580 C u -0.4538 C Th -0.0307H + where W, C u , C Th , and H + stand for water content(g/cc), uranium concentration (g/cc), thorium concentration(g/cc), and nitric acid normality, respectively. Water contents of the mixed uranyl nitrate-thorium nitrate solutions are calculated by using the empirical formular, and compared with the values calculated by Bouly's equation in which an additional data, solution density, is required. The two results show good agreements within 2.7%. (Author)

Investigation of regularities of uranyl salts complexing with neutral bases in nonaqueous media

International Nuclear Information System (INIS)

Kobets, L.V.; Buchikhin, E.P.

1986-01-01

Anhydrous uranyl chloride complexing with neutral oxygen-containing organic bases (sulfoxides, organic phosphates, phosphinates, phosphinoxides, N-oxides) in the acetone medium depending on the donor capacity of neutral molecules is discussed. The constants of 1:1 complexes dissociation are shown to detect no correlation with the donor capacity of neutral bases. At the same time stability constants of complexes increase as the donor capacity of ligands grows. But the dependence is of a complex character and is determined by the nature of neutral molecules. Estimation of uranyl chloride and 0-donor contributions into the values of stability constants and complex formation heats is given

Controlled deprotection and reorganization of uranyl oxo groups in a binuclear macrocyclic environment

Energy Technology Data Exchange (ETDEWEB)

Jones, Guy M.; Arnold, Polly L.; Love, Jason B. [EaStCHEM School of Chemistry, University of Edinburgh (United Kingdom)

2012-12-07

Switching on uranium(V) reactivity: The silylated uranium(V) dioxo complex [(Me{sub 3}SiOUO){sub 2}(L){sub 2}] (A) is inert to oxidation, but after two-electron reduction to [(Me{sub 3}SiOUO){sub 2}(L)]{sup 2-} (1), it can be desilylated to form [OU(μ-O){sub 2}UO(L){sub 2}]{sup 2-} (2) with reinstated uranyl character. Removal of the silyl group uncovers new redox and oxo rearrangement chemistry for uranium, thus reforming the uranyl motif and involving the U{sup VI/V} couple in dioxygen reduction. (Copyright copyright 2012 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim)

Determination of parameters dissolution of yellow-cake. Production of uranyl nitrate - Gas precipitation of AUC

International Nuclear Information System (INIS)

Mellah, A.

1987-07-01

The different stages of the purification cycle of yellow-cakes have been studied thoroughly in order to obtain an ammonium uranyl carbonate (AUC) as an intermediate product of uranium dioxide (UO 2 ). The optimal parameters of yellow-cake dissolution, filtration, extraction by solvent, scrubbing and stripping were determined. An original program of thermodynamic calculation was developed for the determination of the free energies of yellow-cake dissolution reactions. Different numerical methods were used to determine the kinetic constant, the reaction order and correlation equations of uranyl nitrate density as a function of U and H + concentrations, before and after the extraction cycle. For the first time, Algerian filteraids were used for the filtration of uranyl nitrate solutions with satisfactory results. A laboratory designed installation enabled the precipitation of AUC by injection of ammonia and carbon dioxide gases. Interesting results have been obtained and further investigations should be carried out in order to optimize all the paremeters of the gas precipitation of AUC

Variable dimensionality and new uranium oxide topologies in the alkaline-earth metal uranyl selenites AE[UO2)(SeO3)2] (AE=Ca, Ba) and Sr[UO2)(SeO3)2] · 2H2O

International Nuclear Information System (INIS)

Almond, Philip M.; Peper, Shane M.; Bakker, Eric; Albrecht-Schmitt, Thomas E.

2002-01-01

Three new alkaline-earth metal uranyl selenites, Ca[UO 2 )(SeO 3 ) 2 ] (1), Sr[UO 2 )(SeO 3 ) 2 ] · 2H 2 O (2), and Ba[UO 2 )(SeO 3 ) 2 ] (3), have been prepared from the reactions of CaCO 3 and Ca(OH) 2 , SrCl 2 and Sr(OH) 2 , or BaCl 2 and Ba(OH) 2 with UO 3 and SeO 2 under mild hydrothermal conditions. Single-crystal X-ray diffraction experiments reveal that the structures of 1-3 differ in both connectivity and dimensionality even though all contain the same fundamental building unit, namely [UO 2 (SeO 3 ) 4 ]. This polyhedron consists of a linear uranyl unit that is bound by one chelating and three bridging selenite anions creating a pentagonal bipyramidal environment around the U(VI) center. The crystal structure of 1 contains one-dimensional ribbons where the edges are terminated by monodentate selenite anions. The interior of the ribbons are constructed from edge-sharing pentagonal bipyramidal UO 7 units. The structure of 2 is also one-dimensional; however, here there are chains of edge-sharing pentagonal bipyramidal UO 7 dimers that are connected by bridging selenite anions. Ba[(UO 2 )(SeO 3 ) 2 ] (3) is two-dimensional, and the highly ruffled anionic sheets present in this structure are formed from both bridging and chelating/bridging selenite anions bound to uranyl moieties. The anionic substructures in 1-3 are separated by Ca 2+ , Sr 2+ , or Ba 2+ cations. Crystallographic data (193 K, MoKα, λ=0.71073): 1, triclinic, space group P1-bar, a=5.5502(6) A, b=6.6415(7) A, c=11.013(1) A, α=104.055(2) deg., β=93.342(2) deg., γ=110.589(2) deg. , Z=2, R(F)=4.56% for 100 parameters with 1530 reflections with I>2σ(I); 2, triclinic, space group P1-bar, a=7.0545(5) A, b=7.4656(5) A, c=10.0484(6) A, α=106.995(1) deg., β=108.028(1) deg., γ=98.875(1) deg., Z=2, R(F)= 2.43% for 128 parameters with 2187 reflections with I>2σ(I); 3, monoclinic, space group P2 1 /c, a=7.3067(6) A, b=8.1239(7) A, c=13.651(1) A, β=100.375(2) deg., Z=4, R(F)=4.31% for 105 parameters

A microscopic study of the action of uranyl acetate on the erythrocyte at varying molarity and toxicity

International Nuclear Information System (INIS)

Wyatt, J.H.

1977-03-01

Phase contrast and dark field microphotographs were made to record variation of the shape and size changes seen when human erythrocytes are exposed in a number of ways to uranyl acetate in vitro. The degree of hemolysis produced by varying the toxicity of the uranyl acetate solutions was measured, and the results are discussed with particular reference to the possible influence of pH. (author)

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.

Chelating agents in pharmacology, toxicology and therapeutics

International Nuclear Information System (INIS)

1988-01-01

The proceedings contain 71 abstracts of papers. Fourteen abstracts were inputted in INIS. The topics covered include: the effects of chelating agents on the retention of 63 Ni, 109 Cd, 203 Hg, 144 Ce, 95 Nb and the excretion of 210 Po, 63 Ni, 48 V, 239 Pu, 241 Am, 54 Mn; the applications of tracer techniques for studies of the efficacy of chelation therapy in patients with heart and brain disorders; and the treatment of metal poisoning with chelating agents. (J.P.)

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)

2017-12-06

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. We believe that the goal of developing a practical system for uranium separation from seawater will not be attained without new insights into our existing fundamental knowledge of actinide chemistry. We posit that detailed studies of the kinetic and thermodynamic factors that influence interactions between f-elements and ligands with a range of donor atoms is essential to any major advance in this important area. 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. We anticipate that this fundamental science will find use beyond actinide separation technologies in areas such as nuclear waste remediation and nuclear materials.

Renal hemodynamics in uranyl acetate-induced acute renal failure of rabbits

International Nuclear Information System (INIS)

Sudo, M.; Honda, N.; Hishida, A.; Nagase, M.

1977-01-01

The role of renal hemodynamic alterations in the curtailment of renal function was studied in rabbits with uranyl acetate-induced acute renal failure. The day following the i.v. injection of uranyl acetate (2 mg/kg of body wt), renal blood flow (RBF) and clearance of creatinine (Ccr) decreased to approximately 60 and 20% of controls, respectively. Intracortical fractional flow distribution, estimated by radioactive microsphere method, did not change. The extraction ratio of para-aminohippurate (EPAH) decreased and the renal extraction of sodium (CNa/Ccr) increased, with minimal structural change in the kidney. Urine output increased two to three times that of the control. After three days oliguria appeared despite complete recovery of RBF. The zonal flow redistributed toward the deep cortex. CCr and EPAH reached their minimums, concomitantly with tubular necrosis and intratubular casts. After seven days animals could be divided into the oliguric and diuretic groups. CCr and EPAH were higher in the diuretic group, while there was no significant difference in RBF and the flow distribution between groups. Regeneration of damaged tubular cells was found in the diuretic group but not in the oliguric group. The findings suggest the minor roles of RBF and the intracortical flow distribution, and a fundamental role of back leakage of filtrate across damaged tubular epithelium in the maintenance of reduced CCR and urine output during the oliguric stage in rabbits with uranyl acetate-induced renal failure

Process for obtaining ammonium uranyl tri carbonate

International Nuclear Information System (INIS)

Santos, L.R. dos; Riella, H.G.

1992-01-01

The procedure adopted for obtaining Ammonium Uranyl Carbonate (AUC) from uranium hexafluoride (U F 6 ) in a aqueous solutions of ammonium hydrogen carbonate is described in this work. The precipitation is made in temperature and pH controlled. This process consists of three steps: evaporation of U F 6 , AUC precipitation and filtration of the AUC slurry. An attempt is made of correlate the parameters involved in the precipitation process of AUC with its and U O 2 characteristics. (author)

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

International Nuclear Information System (INIS)

Blake, Diane A.

2006-01-01

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

Site-specific conjugation and labelling of prostate antibody 7E11C5.3 (CYT-351) with technetium-99m

International Nuclear Information System (INIS)

Stalteri, M.A.; Mather, S.J.; Belinka, B.A.; Coughlin, D.J.; Chengazi, V.U.; Britton, K.E.

1997-01-01

Attachment of chelating agents to the sugar residues of antibodies for subsequent radiolabelling is an attractive approach since it may have less effect on the immunoreactivity than attachment through lysine residues, which are distributed throughout the antibody and may be present near the antigen binding site. We have attached a new hydrazide-linked chelator CYT-395 (Cytogen Corp., Princeton, N.J.) to the sugar residues of the anti-prostate monoclonal antibody 7E11C5.3 and optimised the conditions for labelling the conjugate with technetium-99m in order to compare the conjugate to 7E11C5.3 antibody labelled directly with technetium using a mercaptoethanol reduction technique. Labelling yields of 70%-90% were obtained at specific activities up to 2000 MBq/mg antibody. The stability of the technetium-labelled conjugate in plasma or to a challenge with 0.1 or 1.0 mM cysteine was similar to that of direct-labelled antibody. In nine patients with prostate cancer, the plasma clearance of the labelled conjugate followed a two-compartment model, with an average β-phase half-life of 31.4±3.9 h. The average urinary clearance at 24 h was 15.3±5.0% of the injected dose. In this group of patients there was no significant difference between the blood and urine clearance of the labelled conjugate, and the clearances of the direct-labelled antibody. (orig.). With 5 figs

Quenching of excited uranyl ion during its photochemical reduction with triphenyl-phosphine : Part IV - effect of heterocyclic molecules

International Nuclear Information System (INIS)

Sidhu, M.S.; Bhatia, P.V.K.

1994-01-01

The presence of heterocyclic compounds triggers off a competition between photophysical and photochemical annihilation of excited uranyl ion during its photochemical reduction with triphenylphosphine. This competition is used to measure Stern-Volmer constant using UV visible spectrophotometer for quenching the uranyl ion luminescence with a number of heterocyclic molecules viz., pyridine, thiophene bipyridyl, tetrahydrofuran and piperidine. (author). 7 refs., 2 figs., 1 tab

Ultrastructure changes produced by the action of uranyl acetate on the human erythrocyte in vitro

Energy Technology Data Exchange (ETDEWEB)

Wyatt, J H

1975-06-01

Human erythrocytes exposed in vitro to low concentrations of uranyl ions are immediately changed in shape to stomatocytes. Electron microscope examination demonstrates that cellular damage is confined to the plasma membrane. Endocytosis of the cell membrane produces groups of inside out membrane-lined vesicles within the cell; lipid from the membrane enters the cell, giving rise to intracellular myelin figures, and breaks are seen in the cell membrane. It is proposed that the lipid fraction of the cell membrane is the primary target for damage by uranyl ions.

Ultrastructure changes produced by the action of uranyl acetate on the human erythrocyte in vitro

International Nuclear Information System (INIS)

Wyatt, J.H.

1975-06-01

Human erythrocytes exposed in vitro to low concentrations of uranyl ions are immediately changed in shape to stomatocytes. Electron microscope examination demonstrates that cellular damage is confined to the plasma membrane. Endocytosis of the cell membrane produces groups of inside out membrane-lined vesicles within the cell; lipid from the membrane enters the cell, giving rise to intracellular myelin figures, and breaks are seen in the cell membrane. It is proposed that the lipid fraction of the cell membrane is the primary target for damage by uranyl ions. (author)

Obligatory reduction of ferric chelates in iron uptake by soybeans.

Science.gov (United States)

Chaney, R L; Brown, J C; Tiffin, L O

1972-08-01

The contrasting Fe(2+) and Fe(3+) chelating properties of the synthetic chelators ethylenediaminedi (o-hydroxyphenylacetate) (EDDHA) and 4,7-di(4-phenylsulfonate)-1, 10-phenanthroline (bathophenanthrolinedisulfonate) (BPDS) were used to determine the valence form of Fe absorbed by soybean roots supplied with Fe(3+)-chelates. EDDHA binds Fe(3+) strongly, but Fe(2+) weakly; BPDS binds Fe(2+) strongly but Fe(3+) weakly. Addition of an excess of BPDS to nutrient solutions containing Fe(3+)-chelates inhibited soybean Fe uptake-translocation by 99+%; [Fe(II) (BPDS)(3)](4-) accumulated in the nutrient solution. The addition of EDDHA caused little or no inhibition. These results were observed with topped and intact soybeans. Thus, separation and absorption of Fe from Fe(3+)-chelates appear to require reduction of Fe(3+)-chelate to Fe(2+)-chelate at the root, with Fe(2+) being the principal form of Fe absorbed by soybean.

Bases for DOT exemption uranyl nitrate solution shipments

International Nuclear Information System (INIS)

Moyer, R.A.

1982-07-01

Uranyl nitrate solutions from a Savannah River Plant reprocessing facility have been transported in cargo tank trailers for more than 20 years without incident during transit. The solution is shipped to Oak Ridge for further processing and returned to SRP in a solid metal form for recycle. This solution, called uranyl nitrate hexahydrate (UNH) solution in Department of Transportation (DOT) regulations, is currently diluted about 2-fold to comply with DOT concentration limits (10% of low specific activity levels) specified for bulk low specific activity (LSA) liquid shipments. Dilution of the process solution increases the number of shipments, the cost of transportation, the cost of shipper preparations, the cost of further reprocessing in the receiving facility to first evaporate the added water, and the total risk to the population along the route of travel. However, the radiological risk remains about the same. Therefore, obtaining an exemption from DOT regulations to permit shipment of undiluted UNH solution, which is normally about two times the present limit, is prudent and more economical. The radiological and nonradiological risks from shipping a unit load of undiluted solution are summarized for the probable route. Data and calculations are presented on a per load or per shipment basis throughout this memorandum to keep it unclassified

Development of radiolabelling techniques of anti-CEA monoclonal antibody

International Nuclear Information System (INIS)

Castiglia, S.G. de

1998-01-01

The purpose of this work was to label monoclonal and polyclonal antibodies with 99 Tc m such as the ior-CEA-1 antibody and polyclonal IgG using a direct method, to check the radiochemical and biological behavior of labelled products, to prepare it under sterile and apyrogenic conditions as a lyophilized kit and to employ it in clinical trials. In addition, a photoactivation method was used to label polyclonal IgG with 99 Tc m and to compare with the established method using mercaptoethanol (2-ME) as the reducing agent. Finally polyclonal IgG was labelled using an indirect method in which a chelator was covalently attached to the protein and the 99 Tc m added as glucoheptonate complex. The properties of 99 Tc m when labelled with monoclonal and polyclonal antibodies by different methods were assessed by in vitro and in vivo studies

Sodium dodecyl sulfate coated alumina modified with a new Schiff's base as a uranyl ion selective adsorbent

Energy Technology Data Exchange (ETDEWEB)

Tashkhourian, J., E-mail: tashkhourian@susc.ac.ir [Department of Chemistry, College of Science, Shiraz University, 71454 Shiraz (Iran, Islamic Republic of); Moradi Abdoluosofi, L.; Pakniat, M. [Department of Chemistry, Faculty of Science, Persian Gulf University, Bushehr 75169 (Iran, Islamic Republic of); Montazerozohori, M. [Department of Chemistry, Faculty of Science, Yasouj University, Yasouj (Iran, Islamic Republic of)

2011-03-15

A simple and selective method was used for the preconcentration and determination of uranium(VI) by solid-phase extraction (SPE). In this method, a column of alumina modified with sodium dodecyl sulfate (SDS) and a new Schiff's base ligand was prepared for the preconcentration of trace uranyl(VI) from water samples. The uranium(VI) was completely eluted with HCl 2 M and determined by a spectrophotometeric method with Arsenazo(III). The preconcentration steps were studied with regard to experimental parameters such as amount of extractant, type, volume and concentration of eluent, pH, flow rate of sample source and tolerance limit of diverse ions on the recovery of uranyl ion. A preconcentration factor more than 200 was achieved and the average recovery of uranyl(VI) was 99.5%. The relative standard deviation was 1.1% for 10 replicate determinations of uranyl(VI) ion in a solution with a concentration of 5 {mu}g mL{sup -1}. This method was successfully used for the determination of spiked uranium in natural water samples.

Development of iron chelators for Cooley's anemia. Final report

International Nuclear Information System (INIS)

Crosby, W.H.; Green, R.

1982-01-01

Iron chelators were screened in an iron-loaded rat model using selective radioiron probes. In all experiments, chelators D and F, in that order, induced significant loss of radioiron compared with controls. However, use of chelator D was associated with side effects, and resulted in the death of some animals. There was some evidence that chelator A also caused iron loss significantly greater than controls. Chelators B, C and E were without apparent enhancing effect on radioiron excretion. This was a blind study and the compounds used were A - 2,3-Dihydroxybenzoic acid; B - N,N1-Dimethyladipohydroxamic acid; C - DL-Phenylalanine hydroxamic acid; D - Ethylenediamine-N,N1-bis(2-hydroxphenylacetic acid); E - Propionohydroxamic acid; and F - Deferrioxamine B

The system uranyl nitrate-dietyl ether-water. Extraction by water in spray and packed columns from uranyl nitrate-either solutions

International Nuclear Information System (INIS)

Perez Luina, A.; Gutierrez Jodra, L.

1960-01-01

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

Interaction of uranyl ions with snake venom proteins from Lachesis muta muta

International Nuclear Information System (INIS)

MacCordick, H.J.; Taghva, F.

1997-01-01

The reaction product of uranyl nitrate with whole-protein Bushmaster snake venom in nitrate buffer at pH 3.5 has been studied. The maximum uptake of uranium was 291 μmol U x g -1 of venom. The infrared spectrum of the product showed an asymmetric O-U-O vibration at 921 cm -1 typical of complex formation with the uranyl ion. Stability measurements with the UO 2 2+ -protein complex in neutral medium indicated moderate hydrolytic stability, with 14% dissociation after 16 hours at 0 deg C. Neutron irradiation and desorption studies with a 235 U-labelled complex showed that generated fission products such as lanthanides and barium were readily lixiviated at pH 7, whereas Ru and Zr were highly retained by the protein substrate. (author)

Crystallization characteristics of ammonium uranyl carbonate (AUC) in ammonium carbonate solutions

International Nuclear Information System (INIS)

Kim, T.J.; Jeong, K.C.; Park, J.H.; Chang, I.S.; Choi, C.S.

1994-01-01

Ammonium carbonate solutions with an excessive amount of NH 3 were produced in a commercial AUC (ammonium uranyl carbonate) conversion plant. In this study the AUC crystals, precipitated with uranyl nitrate and ammonium carbonate solutions prepared in the laboratory, were characterized to determine the feasibility of recycling ammonium carbonate solution. The AUC crystals were easily agglomerated with the increasing concentration of CO 3 2- and mole ratio of NH 4 + /CO 3 2- in ammonium carbonate solution. Effects of a mixing system for the solution in the AUC crystallizer and the feed location of the solution onthe agglomeration of AUC crystals were also studied along with the effects of agglomerated AUC powders on UO 2 powders. Finally, the feasibility of manufacturing UO 2 fuel with a sintered pellet density of 10.52 g/cm 3 , using the AUC powders generated in this experiment, was demonstrated. (orig.)

Synthesis and investigation of uranyl molybdate UO2MoO4

International Nuclear Information System (INIS)

Nagai, Takayuki; Sato, Nobuaki; Kitawaki, Shin-ichi; Uehara, Akihiro; Fujii, Toshiyuki; Yamana, Hajimu; Myochin, Munetaka

2013-01-01

In order to examine easily synthetic conditions of uranyl molybdate, UO 2 MoO 4 , used for the reprocessing process study of spent nuclear oxide fuels in alkaline molybdate melts, the uranium molybdate compounds were produced from U 3 O 8 powder and anhydrous MoO 3 reagent. The results of having investigated them in solid state by using X-ray diffractometry and Raman spectrometry, it was confirmed that UO 2 MoO 4 could be synthesized by heating mixed powder of U 3 O 8 and MoO 3 with stoichiometric mole ratio at 770 °C for 4 h under air atmosphere. Moreover, adding this UO 2 MoO 4 into Li 2 MoO 4 -Na 2 MoO 4 eutectic melt, most of the dissolved uranium species in the melt were observed as hexa–valent uranyl ions by absorption spectrophotometry

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)

Uranyl Photocleavage of Phosphopeptides Yields Truncated C-Terminally Amidated Peptide Products

DEFF Research Database (Denmark)

Elnegaard, Rasmus L B; Møllegaard, Niels Erik; Zhang, Qiang

2017-01-01

photocleavage reaction of a tetraphosphorylated β-casein model peptide. We show that the primary photocleavage products of the uranyl-catalysed reaction are C-terminally amidated. This could be of great interest to the pharmaceutical industry, as efficient peptide amidation reactions are one of the top...

Uranyl phosphate mineral in Gapyeong area

International Nuclear Information System (INIS)

Chung, S.J.

1980-01-01

An uranyl phosphate crystal from Gapeong area is studied by means of single crystal x-ray diffraction and electron microscopic qualitative analysis of chemical contents. The crystal is identified as meta-ankoleite which has a unit cell of super structure with a=b=6.99 A, c=17.69 A and space group P4 2 22. There exists some indication in the total fluorescent spectrum of the sample that potassium may be partially substituted by calcium. The chemical formula of this meta-ankoleite may be expressed by Ksub(1-2x)Casub(x)(UO 2 PO 4 ) (H 2 O)sub(3-x). (Author)

New Insights into the Functional Behavior of Antibodies as Revealed by Binding Studies on an Anti-Uranium Monoclonal Antibody

International Nuclear Information System (INIS)

Blake, Diane A.; Xia Li; Haini Yu; Blake, Robert C.

2004-01-01

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

Tritium gettering from air with hydrogen uranyl phosphate

International Nuclear Information System (INIS)

Souers, P.C.; Uribe, F.S.; Stevens, C.G.; Tsugawa, R.T.

1985-01-01

Hydrogen uranyl phosphate (HUP), a solid proton electrolyte, getters tritium gas and water vapor from air by DC electrical action. We have reduced the formation of residual tritiated water to less than 2%, and demonstrated that HUP can clean a 5.5 m 3 working glove box. Data are presented to illustrate the parameters of the gettering and a model is derived. Two other tritium gettering electrolytes have been discovered. 9 refs., 5 figs., 3 tabs

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.

TG/DTA and X ray Diffraction Studies on Ammonium Uranyl Nitrate

International Nuclear Information System (INIS)

Kim, Byung Ho; Lee, Young Bum; Jeong, Ji Young; Choi, Jong Hyun; Kim, Tae Joon; Nam, Ho Yun; Kim, Jong Man

2011-01-01

Ammonium uranyl nitrate (AUN) is an important intermediate product during conversion of a uranyl nitrate[UO 2 (NO 3 ) 2 ] solution to UO 2 powder for the fabrication of nuclear fuels, the so-called modified direct denitration (MDD) process. The MDD process involves the thermal decomposition of AUN double salts, which are prepared from a mixture consisting of a UO 2 (NO 3 ) 2 solution and NH 4 NO 3 . The physical and chemical properties of an oxide powder depend upon its thermal treatment. Three double salts are known for the UO 2 (NO 3 ) 2 - NH 4 NO 3 -H 2 O system, but there have been only a few studies done on thermal decomposition of these salts. Therefore, the objective of this study is to investigate the reaction pathways during a thermal decomposition and reduction of AUN to achieve a better knowledge of the influence of an AUN preparation process and thermal decomposition procedures on uranium oxides under a nitrogen, air, or hydrogen atmosphere

3-hydroxy-2(1H)-pyridinone chelating agents

Science.gov (United States)

Raymond, K.; Xu, J.

1999-04-06

Disclosed is a series of improved chelating agents and the chelates formed from these agents, which are highly effective upon both injection and oral administration. Several of the most effective are of low toxicity. These chelating agents incorporate within their structure 3-hydroxy-2-pyridinone (3,2-HOPO) moieties with a substituted carbamoyl group ortho to the hydroxy group of the hydroxypyridinone ring. The electron-withdrawing carbamoyl group increases the acidity, as well as the chemical stability towards oxidation and reduction, of the hydroxypyridinones. In the metal complexes of the chelating agents, the amide protons form very strong hydrogen bonds with the adjacent HOPO oxygen donor, making these complexes very stable at physiological conditions. The terminal N-substituents provide a certain degree of lipophilicity to the 3,2-HOPO, increasing oral activity. 2 figs.

Photochemical methodologies for organic waste treatment: advanced oxidation process using uranyl ion with H2O2

International Nuclear Information System (INIS)

Naik, D.B.; Sarkar, S.K.; Mukherjee, T.

2009-01-01

Excited uranyl ion is able to degrade dyes such as thionine and methylene blue on irradiation with 254 nm/300 nm light. By adding H 2 O 2 along with uranyl ion, photodegradation takes place with visible light and also with enhanced rate. The hydroxyl radicals generated in the reoxidation of U(IV)/UO 2 + to UO 2 2+ are responsible for this enhanced degradation. The above advanced oxidation process (AOP) was applied to study the oxidation of 2-propanol to acetone. (author)

Biosensing for the Environment and Defence: Aqueous Uranyl Detection Using Bacterial Surface Layer Proteins

Directory of Open Access Journals (Sweden)

David J.R. Conroy

2010-05-01

Full Text Available The fabrication of novel uranyl (UO22+ binding protein based sensors is reported. The new biosensor responds to picomolar levels of aqueous uranyl ions within minutes using Lysinibacillus sphaericus JG-A12 S-layer protein tethered to gold electrodes. In comparison to traditional self assembled monolayer based biosensors the porous bioconjugated layer gave greater stability, longer electrode life span and a denser protein layer. Biosensors responded specifically to UO22+ ions and showed minor interference from Ni2+, Cs+, Cd2+ and Co2+. Chemical modification of JG-A12 protein phosphate and carboxyl groups prevented UO22+ binding, showing that both moieties are involved in the recognition to UO22+.

PVC membrane based potentiometric sensor for uranyl ion using thenoyl trifluoro acetone as ionophore

International Nuclear Information System (INIS)

Nanda, D.; Chouhan, H.P.S.; Maiti, B.

2004-01-01

Uranyl ion selective electrode based on thenoyl trifluoro acetone (TTA) incorporated into a polyvinyl chloride (PVC) membrane has been developed where dibutyl phthalate and sodium tetraphenyl borate have been used as plasticizer and anion excluder respectively. The PVC membrane containing the active ionophore, TTA, and the other ingredients has been directly cast a graphite electrode. The electrode shows near Nernstian response to UO 2 2+ in the concentration range of 10 -1 to 10 -6 mol. L -1 an average slope of 30 mV/decade. Alkali and alkaline earth ions do not interfere with the determination of uranyl ion. Interference of transition metal ions and Th (IV) is eliminated using EDTA. (author)

Use of chelating agents as immovable phase in extraction chromatography

International Nuclear Information System (INIS)

Sebesta, F.

1978-01-01

Extraction chromatography using chelating agents is reviewed. The theory of element extraction by chelating agents and factors influencing this process (pH, extracting agent concentration in organic phase, masking agent concentration in aqueous phase) are briefly considered. The effect of kinetic factors on the extraction chromatography process is discussed. Ways of preparing columns are emphasized. Examples of using chelating reagents in various extraction chromatography systems are given. β-Diketones, oximes, hydroxamic acids, dithizon, diethyl dithiocarbamic acid are chosen as chelating agents

Crystal chemistry of uranyl carboxylate coordination networks obtained in the presence of organic amine molecules

Energy Technology Data Exchange (ETDEWEB)

Mihalcea, Ionut; Henry, Natacha; Loiseau, Thierry [Unite de Catalyse et Chimie du Solide (UCCS) - UMR CNRS 8181, Universite de Lille Nord de France, USTL-ENSCL, Villeneuve d' Ascq (France)

2014-03-15

Three uranyl isophthalates (1,3-bdc) and two uranyl pyromellitates (btec) of coordination-polymer type were hydrothermally synthesized (200 C for 24 h) in the presence of different amine-based molecules [1,3-diaminopropane (dap) or dimethylamine (dma) originating from the in situ decomposition of N,N-dimethylformamide]. (UO{sub 2}){sub 2}(OH){sub 2}(H{sub 2}O)(1,3-bdc).H{sub 2}O (1) is composed of inorganic tetranuclear cores, which are linked to each other through the isophthalato ligand to generate infinite neutral ribbons, which are intercalated by free H{sub 2}O molecules. The compounds (UO{sub 2}){sub 1.5}(H{sub 2}O)(1,3-bdc){sub 2}.0.5H{sub 2}dap.1.5H{sub 2}O (2) and UO{sub 2}(1,3-bdc){sub 1.5}.0.5H{sub 2}dap.2H{sub 2}O (3) consist of discrete uranyl-centered hexagonal bipyramids connected to each other by a ditopic linker to form a single-layer network for 2 or a double-layer network for 3. The protonated diamine molecules are located between the uranyl-organic sheets and balance the negative charge of the layered sub-networks. The phase (UO{sub 2}){sub 2}O(btec).2Hdma.H{sub 2}O (4) presents a 2D structure built up from tetranuclear units, which consist of two central sevenfold coordinated uranium centers and two peripheral eightfold coordinated uranium centers. The connection of the resulting tetramers through the pyromellitate molecules generates an anionic layerlike structure, in which the protonated dimethylammonium species are inserted. The compound UO{sub 2}(btec).2Hdma (5) is also a lamellar coordination polymer, which contains isolated eightfold coordinated uranium cations linked through pyromellitate molecules and intercalated by protonated dimethylammonium species. In both phases 4 and 5, the btec linker has non-bonded carboxyl oxygen atoms, which preferentially interact with the protonated amine molecules through a hydrogen-bond network. The different illustrations show the structural diversity of uranyl-organic coordination polymers with organic

Chelating impact assessment of biological ad chemical chelates on metal extraction from contaminated soils

International Nuclear Information System (INIS)

Manwar, S.; Iram, S.

2014-01-01

Soil contamination is the result of uncontrolled waste dumping and poor practices by humans. Of all the pollutants heavy metals are of particular concern due to their atmospheric deposition, leaching capacity and non-biodegradability. Heavy metal containing effluent is discharged into the agricultural fields and water bodies. This results in the accumulation of heavy metals in soil and the crops grown on that soil. Studies have revealed detrimental impacts on soil fertility and the poor health of animals and humans. Phytoextraction is widely researched for remediation of heavy metal contaminated soil. To enhance the effect of phytoextraction heavy metals have to be available to the plants in soluble form. In this study the potential of different chelating agents was assessed in solubilizing the heavy metals making easy for plants to uptake them. For this purpose efficient chemical and biological chelating agent had to be identified. Along with that an optimum dose and application time for chemical chelating agent was determined. Ethylenediamine tetraacetic acid (EDTA), Diethylene triamine pentaacetic acid (DTPA), Nitriloacetic acid (NTA) were applied to the soil, containing Pb, Cr, Cu and Cd, at different concentrations and application time. Aspergillus niger and Aspergillus flavus were incubated in soil for different time periods. In correspondence with findings of the study, Pb and Cr were best solubilized by 5mM EDTA. For Cd and Cu 5mM DTPA carried out efficient chelation. NTA showed relatively inadequate solubilisation, although for Cr it performed equal to EDTA. A. niger and A. flavus instead of solubilizing adsorbed the metals in their biomass. Adsorption was mainly carried out by A. niger. (author)

Inhibition of mannosidase in hybridomas yields monoclonal antibodies with greater capacity for carbohydrate labeling

International Nuclear Information System (INIS)

Simonson, R.B.; Ultee, M.E.; Long, C.G.; Gillette, R.W.; McKearn, T.J.; Rodwell, J.D.

1988-01-01

Labeling an antibody site specifically through its carbohydrate residues preserves more of its antigen-binding activity than does labeling through protein moieties. To boost the amount of immunoglobulin G carbohydrate capable of being labeled, we treated hybridoma cells with a mannosidase inhibitor, deoxymannojirimycin (dMM). Polyacrylamide gel electrophoresis showed formation of a glycoprotein with high mannose content, in that endo-beta-N-acetylglucosaminidase H 3.2.1.96) could digest the antibody from the dMM-treated cells, but not from control cultures. Carbohydrate analysis confirmed this conclusion, indicating that the antibody from the dMM-treated cells had twice as much mannose as did the control antibody. The glucosamine content of the treated-cells' antibodies was half that of the control, and no additional carbohydrate residues were detectable in the antibodies secreted by the dMM-treated cells. We conjugated both the dMM and control antibodies through their carbohydrate to a chelator. In labeling, the dMM antibody conjugate incorporated approximately threefold as much 111 In isotope as the control conjugate. The two labeled antibodies were injected into mice and showed similar organ distributions

Calorimetric measurement of the enthalpy of extraction of uranyl nitrate by tri-n-amyl phosphate

International Nuclear Information System (INIS)

Srinivasan, T.G.; Vasudeva Rao, P.R.; Venugopal, V.; Sood, D.D.

2002-01-01

Enthalpy of extraction of uranyl nitrate by tri n-amyl phosphate (TAP) and its solutions in n-dodecane has been directly measured by solution calorimetry for the first time. Measurements have been made at 303±1 K, in both forward as well as the reverse extraction modes. The enthalpies of the accompanying reactions such as the dilution of the uranyl nitrate in the aqueous phase, the hydration of TAP, the mixing of TAP and n-dodecane, the mixing of the metal-solvate (UO 2 (NO 3 ) 2 ·2TAP) and n-dodecane and mixing of the metal-solvate and TAP have also been independently measured and used to derive both the equilibrium state enthalpies and the standard state enthalpies for the extraction. Two distinct standard states have been used for the organic phase, viz., 1) all solutes infinitely diluted in diluent (ΔH*) and 2) all solutes infinitely diluted in the water saturated extractant (ΔH 0 ). The results have been compared with the enthalpies of extraction measured by employing the temperature dependence of the distribution ratio as well as calorimetry reported in the literature for extraction of uranyl nitrate by TAP and TBP. (author)

Glyphosate, a chelating agent-relevant for ecological risk assessment?

Science.gov (United States)

Mertens, Martha; Höss, Sebastian; Neumann, Günter; Afzal, Joshua; Reichenbecher, Wolfram

2018-02-01

Glyphosate-based herbicides (GBHs), consisting of glyphosate and formulants, are the most frequently applied herbicides worldwide. The declared active ingredient glyphosate does not only inhibit the EPSPS but is also a chelating agent that binds macro- and micronutrients, essential for many plant processes and pathogen resistance. GBH treatment may thus impede uptake and availability of macro- and micronutrients in plants. The present study investigated whether this characteristic of glyphosate could contribute to adverse effects of GBH application in the environment and to human health. According to the results, it has not been fully elucidated whether the chelating activity of glyphosate contributes to the toxic effects on plants and potentially on plant-microorganism interactions, e.g., nitrogen fixation of leguminous plants. It is also still open whether the chelating property of glyphosate is involved in the toxic effects on organisms other than plants, described in many papers. By changing the availability of essential as well as toxic metals that are bound to soil particles, the herbicide might also impact soil life, although the occurrence of natural chelators with considerably higher chelating potentials makes an additional impact of glyphosate for most metals less likely. Further research should elucidate the role of glyphosate (and GBH) as a chelator, in particular, as this is a non-specific property potentially affecting many organisms and processes. In the process of reevaluation of glyphosate its chelating activity has hardly been discussed.

Chelation therapy to prevent diabetes-associated cardiovascular events.

Science.gov (United States)

Diaz, Denisse; Fonseca, Vivian; Aude, Yamil W; Lamas, Gervasio A

2018-05-24

For over 60 years, chelation therapy with disodium ethylene diamine tetraacetic acid (EDTA, edetate) had been used for the treatment of cardiovascular disease (CVD) despite lack of scientific evidence for efficacy and safety. The Trial to Assess Chelation Therapy (TACT) was developed and received funding from the National Institutes of Health (NIH) to ascertain the safety and efficacy of chelation therapy in patients with CVD. This pivotal trial demonstrated an improvement in outcomes in postmyocardial infarction (MI) patients. Interestingly, it also showed a particularly large reduction in CVD events and all-cause mortality in the prespecified subgroup of patients with diabetes. The TACT results may support the concept of metal chelation to reduce metal-catalyzed oxidation reactions that promote the formation of advanced glycation end products, a precursor of diabetic atherosclerosis. In this review, we summarize the epidemiological and basic evidence linking toxic metal accumulation and diabetes-related CVD, supported by the salutary effects of chelation in TACT. If the ongoing NIH-funded TACT2, in diabetic post-MI patients, proves positive, this unique therapy will enter the armamentarium of endocrinologists and cardiologists seeking to reduce the atherosclerotic risk of their diabetic patients.

Structural evolution of a uranyl peroxide nano-cage fullerene: U60, at elevated pressures

Science.gov (United States)

Turner, K. M.; Lin, Y.; Zhang, F.; McGrail, B.; Burns, P. C.; Mao, W. L.; Ewing, R. C.

2015-12-01

U60 is a uranyl peroxide nano-cage that adopts a highly symmetric fullerene topology; it is topologically identical to C60. Several studies on the aqueous-phase of U60 clusters, [UO2(O2)(OH)]6060-, have shown its persistence in complex solutions and over lengthy time scales. Peroxide enhances corrosion of nuclear fuel in a reactor accident-uranyl peroxides often form near contaminated sites. U60 (Fm-3) crystallizes with approximate formula: Li68K12(OH)20[UO2(O2)(OH)]60(H2O)310. Here, we have used the diamond anvil cell (DAC) to examine U60 to understand the stability of this cluster at high pressures. We used a symmetric DAC with 300 μm culet diamonds and two different pressure-transmitting media: a mixture of methanol+ethanol and silicone oil. Using a combination of in situ Raman spectroscopy and synchrotron XRD, and electrospray ionization mass spectroscopy (ESI-MS) ex situ, we have determined the pressure-induced evolution of U60. Crystalline U60 undergoes an irreversible phase transition to a tetragonal structure at 4.1 GPa, and irreversibly amorphizes at 13 GPa. The amorphous phase likely consists of clusters of U60. Above 15 GPa, the U60 cluster is irreversibly destroyed. ESI-MS shows that this phase consists of species that likely have between 10-20 uranium atoms. Raman spectroscopy complements the diffraction measurements. U60 shows two dominant vibrational modes: a symmetric stretch of the uranyl U-O triple bond (810 cm-1), and a symmetric stretch of the U-O2-U peroxide bond (820 cm-1). As pressure is increased, these modes shift to higher wavenumbers, and overlap at 4 GPa. At 15 GPa, their intensity decreases below detection. These experiments reveal several novel behaviors including a new phase of U60. Notably, the amorphization of U60 occurs before the collapse of its cluster topology. This is different from the behavior of solvated C60 at high pressure, which maintains a hcp structure up to 30 GPa, while the clusters disorder. These results suggest

Biological behavior of 188Re-biotin chelate for multistep therapy with the avidin-biotin system

International Nuclear Information System (INIS)

Choi, T. H.; Ahn, S. H.; Choi, C. W.; Woo, K. S.; Jung, W. S.; Lim, S. J.; Lim, S. M.

1999-01-01

The purpose of this study was to test the three-step targeting of tumors in mice using biotinylated antibody, streptavidin and radiolabeled biotin for radioimmunotherapy (RAIT). Three-step pretargetting can potentially decreases harmful radiation to normal tissues in radioimmunotherapy. 188 Re from 188 W- 188 Re generator, is recently introduced in therapeutic nuclear medicine and made it possible to use whenever needed. We studied biotin-chelates MGB for use in the avidin/biotin pretargetting system. Chelates that hold radiometals with high stability under physiological conditions are essential to avoid excessive radiation damage to non-target cells. We synthesized MAG 2 GABA-Biocytin (MGB), labeled with 188 Re and evaluated biological behavior of 188 Re-MGB. biotinyl MAG 2 GABA bind the therapeutic radiometal 188 Re with excellent in vitro stability and have the required physiological properties for pretargetted therapy. In normal mice, 188 Re-MGB was excreted via hepatobiliary pathway, %ID/g of GI tract was 52.1 at 120min. In Raji cells tumor bearing nude mice, liver and colon were higher than those of normal mouse. Tumor uptake at 120min was 0.05%ID/g. 188 Re-MGB may have a role in pretargetted radioimmunotherapy

Removal of toxic uranium from synthetic nuclear power reactor effluents using uranyl ion imprinted polymer particles.

Science.gov (United States)

Preetha, Chandrika Ravindran; Gladis, Joseph Mary; Rao, Talasila Prasada; Venkateswaran, Gopala

2006-05-01

Major quantities of uranium find use as nuclear fuel in nuclear power reactors. In view of the extreme toxicity of uranium and consequent stringent limits fixed by WHO and various national governments, it is essential to remove uranium from nuclear power reactor effluents before discharge into environment. Ion imprinted polymer (IIP) materials have traditionally been used for the recovery of uranium from dilute aqueous solutions prior to detection or from seawater. We now describe the use of IIP materials for selective removal of uranium from a typical synthetic nuclear power reactor effluent. The IIP materials were prepared for uranyl ion (imprint ion) by forming binary salicylaldoxime (SALO) or 4-vinylpyridine (VP) or ternary SALO-VP complexes in 2-methoxyethanol (porogen) and copolymerizing in the presence of styrene (monomer), divinylbenzene (cross-linking monomer), and 2,2'-azobisisobutyronitrile (initiator). The resulting materials were then ground and sieved to obtain unleached polymer particles. Leached IIP particles were obtained by leaching the imprint ions with 6.0 M HCl. Control polymer particles were also prepared analogously without the imprint ion. The IIP particles obtained with ternary complex alone gave quantitative removal of uranyl ion in the pH range 3.5-5.0 with as low as 0.08 g. The retention capacity of uranyl IIP particles was found to be 98.50 mg/g of polymer. The present study successfully demonstrates the feasibility of removing uranyl ions selectively in the range 5 microg - 300 mg present in 500 mL of synthetic nuclear power reactor effluent containing a host of other inorganic species.

Preparation, Spectroscopic Investigation and Biological Activity of New Mixed Ligand Chelates

International Nuclear Information System (INIS)

Alassbaly, F.S.; Ajaily, M.M.E.

2014-01-01

Preparation and investigation of new Co(II), Ni(II), Zn(II) and Cr(III) chelates with mixed ligands including Schiff base (L1) formed from the condensation of 4-dimethylaminobenzaldehyde with 2-aminophenol and anthranilic acid (L2) were studied. The obtained Schiff base and mixed ligand chelates were subjected to several physiochemical techniques, in terms of CHN elemental analyses, molar conductivity, magnetic moment measurements, infrared, proton nuclear magnetic resonance, electronic and mass spectra. The analytical data showed the formation of the Schiff base compound and the ratio of metal to ligands of the chelates are 1:1:1(M:L1:L2). The infrared spectral data exhibited that the used ligands behaving as bidentate ligands towards the metal ions. The proton nuclear magnetic resonance spectral data showed the signals of the active groups in the ligands which entered in chelation with Zn(II) metal ion. The electronic spectral results showed the existence of pie (phenyl ring) and n = pie (C=N) of the ligands and suggested the geometrical structures of the chelates. Meanwhile, the mass spectral data revealed the fragmentations of the Schiff base, anthranilic acid and their Ni(II) mixed ligand chelate has been preformed the only chelate conducted for justification. All the prepared mixed chelates were non-electrolyte in nature. The antibacterial activity of the Schiff base, anthranilic acid, metal salts and mixed ligand chelates were studied and found to be that mixed ligand chelates have the most biological activity in comparison to the free ligands and salts. (author)

Studying of the dehydration process of uranyl nitrate hexahydrate (Unh)

International Nuclear Information System (INIS)

Badalov, A.; Kamalov, J.J.; Homidov, B.J.; Mirsaidov, I.U.; Eshbekov, N.R.

2005-01-01

By the tensimeteric method is studying the dehydration process of uranyl nitrate hexahydrate (Unh). It is shown, that the temperature interval 300-400 K in equilibrium conditions the dehydration process of Unh runs in three stages. According to the equations of dependence of saturated steam pressure from temperature, the thermodynamic characteristics of each stage of the dehydration process of Unh are calculated

Crystal structure of the (REE)-uranyl carbonate mineral kamotoite-(Y)

Czech Academy of Sciences Publication Activity Database

Plášil, Jakub; Petříček, Václav

2017-01-01

Roč. 81, č. 3 (2017), s. 653-660 ISSN 0026-461X R&D Projects: GA MŠk LO1603 EU Projects: European Commission(XE) CZ.2.16/3.1.00/24510 Institutional support: RVO:68378271 Keywords : kamotoite-(Y) * uranyl carbonate * rare-earth elements * crystal structure Subject RIV: DB - Geology ; Mineralogy OBOR OECD: Geology Impact factor: 1.285, year: 2016

Study of cyclization of chelating compounds using electrospray ionization mass spectrometry

International Nuclear Information System (INIS)

Shi Ying; Campbell, J.A.

2000-01-01

Electrospray ionization mass spectrometry (ESI-MS) was used for the study of cyclization of organic chelating compounds (chelators). Four chelating compounds were studied: Symmetrical ethylenediaminediacetic acid (s-EDDA), Unsymmetrical ethylenediaminediacetic acid (u-EDDA), N-(2-hydroxyethyl) ethylenediaminetriacetic acid (HEDTA), and N-(2-hydroxyethyl)iminodiacetic acid (HEIDA). The chelators were cyclized with treatments of acids and heating. The open and cyclized form of the chelators were semi-quantified by both positive and negative ion modes ESI-MS. The kinetics of chelator cyclization was studied as a function of reaction temperature and the pH of the matrix. The cyclization of s-EDDA was found to be a pseudo-first order reaction in s-EDDA and overall second order. The cyclizations of HEIDA and HEDTA are reversible reactions. Higher temperature and lower pH favors cyclization. (author)

Surface analysis of uranyl fluoride layers with a glow discharge lamp

International Nuclear Information System (INIS)

Nel, J.T.; Stander, C.M.; Boehmer, R.G.

1991-01-01

Surface analysis with a Grimm-type glow discharge lamp was used to analyse uranyl fluoride layers that had formed on a nickel substrate after exposure to UF 6 . Narrow-band optical filters were used to isolate the intensities of three fluorine emission lines. An in-depth profile of layer composition was obtained. (author)

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.

Interfacial tension in systems involving TBP in dodecane, nitric acid, uranyl nitrate and water

International Nuclear Information System (INIS)

Kolarik, Z.; Pipkin, N.

1982-08-01

The interfacial tension was measured at 25 0 C in the systems TBP - n-dodecane/nitric acid - water and TBP - n-dodecane/nitric acid - uranyl nitrate - water. Empirical equations describing the interfacial tension as a function of the concentration of TBP in the starting organic phase and of uranium-(VI) and nitric acid in the equilibrium aqueous phase were suggested. In the absence of uranium (VI), the interfacial tension can also be correlated with the concentration of water in the equilibrium organic phase. Free TBP, hydrated or nonhydrated, and hydrated TBP solvates of nitric acid are interfacially active. Anhydrous TBP solvates of nitric acid and the TBP solvate of uranyl nitrate, which neither is hydrated, do not exhibit any visible interfacial activity. (orig.) [de

Thermal decomposition of uranyl nitrate hexahydrate. Study of intermediate reaction products; Decomposition thermique du nitrate d'uranyle hexahydrate etude des intermediaires de cette decomposition

Energy Technology Data Exchange (ETDEWEB)

Chottard, G [Commissariat a l' Energie Atomique, Saclay (France). Centre d' Etudes Nucleaires

1970-07-01

The thermal decomposition of uranyl nitrate hexahydrate has been carried but at constant pressure and constant rate of reaction. The following intermediary products have been shown to exist and isolated: UO{sub 2}(NO{sub 3}){sub 2}.3H{sub 2}O; UO{sub 2}(NO{sub 3}){sub 2}. 2H{sub 2}O; UO{sub 2}(NO{sub 3}){sub 2}. H{sub 2}O; UO{sub 2}(NO{sub 3}){sub 2} and UO{sub 3}. These products, together with the hexahydrate UO{sub 2} (NO{sub 3}){sub 2}.6H{sub 2}O, have been studied by: - X-ray diffraction, using the Debye-Scherrer method.- infra-red spectrography: determination of the type of bonding for the water and the nitrate groups. - nuclear magnetic resonance: study of the mobility of water molecules. The main results concern: - the water molecule bonds in the series of hydrates with 6.3 and 2 H{sub 2}O. - isolation and characterization of uranyl nitrate monohydrate, together with the determination of its molecular structure. - the mobility of the water molecules in the series of the hydrates with 6.3 and 2 H{sub 2}O. An analysis is made of the complementary results given by infra-red spectroscopy and nuclear magnetic resonance; they are interpreted for the whole of the hydrate series. [French] La decomposition thermique du nitrate d'uranyle hexahydrate a ete effectuee en operant a pression et vitesse de decomposition constantes. Les produits intermediaires suivants ont ete mis en evidence et isoles: UO{sub 2}(NO{sub 3}){sub 2}, 3H{sub 2}O; UO{sub 2}(NO{sub 3}){sub 2}, 2H{sub 2}O; UO{sub 2}(NO{sub 3}){sub 2},H{sub 2}O; UO{sub 2}(NO{sub 3}){sub 2} et UO{sub 3}. Ces composes, ainsi que l'hexahydrate UO{sub 2}(NO{sub 3} ){sub 2}, 6H{sub 2}O ont ete etudies par: - diffraction des rayons X, selon la methode Debye-Scherrer.- spectrographie infra-rouge: determination des modes de liaison de l'eau et des groupements nitrate. - resonance magnetique nucleaire: etude de la mobilite des molecules d'eau. Les principaux resultats portent sur: - les liaisons des molecules d'eau dans la

Bifunctional chelates of Rh-105 and Au-199 as potential radiotherapeutic agents

International Nuclear Information System (INIS)

Troutner, D.E.; Schlemper, E.O.

1990-01-01

Since last year we have: continued the synthesis of pentadentate bifunctional chelating agents based on diethylene triamine; studied the chelation Rh-105, Au-198 (as model for Au-199) and Tc-99m with these agents as well as chelation of Pd-109, Cu-67, In-111, and Co-57 with some of them; synthesized a new class of potential bifunctional chelating agents based on phenylene diamine; investigated the behavior of Au-198 as a model for Au-199; begun synthesis of bifunctional chelating agents based on terpyridly and similar ligands; and continued attempts to produce tetradentate bifunctional chelates based on diaminopropane. Each of these will be addressed in this report

Microporous uranyl chromates successively formed by evaporation from acidic solution

Energy Technology Data Exchange (ETDEWEB)

Siidra, Oleg I.; Nazarchuk, Evgeny V.; Bocharov, Sergey N.; Kayukov, Roman A. [St. Petersburg State Univ. (Russian Federation). Dept. of Crystallography; Depmeier, Wulf [Kiel Univ. (Germany). Inst. fuer Geowissenschaften

2018-04-01

The first microporous framework structures containing uranium and chromium have been synthesized and characterized. Rb{sub 2}[(UO{sub 2}){sub 2}(CrO{sub 4}){sub 3}(H{sub 2}O){sub 2}](H{sub 2}O){sub 3} (1) was crystallized from uranyl chromate solution by evaporation. Further evaporation led to increased viscosity of the solution and overgrowing of Rb{sub 2}[(UO{sub 2}){sub 2}(CrO{sub 4}){sub 3}(H{sub 2}O)](H{sub 2}O) (2) on the crystals of 1. With respect to 1, the framework of 2 is partially dehydrated. Both frameworks differ compositionally by only one water molecule, but this seemingly small difference affects significantly the pore size and overall structural topology of the frameworks, which present very different flexibility of the U-O-Cr links. These are rigid in the pillared framework of 1, in contrast to 2 where the U-O-Cr angles range from 126.3 to 168.2 , reflecting the substantial flexibility of Cr-O-U connections which make them comparable to the corresponding Mo-O-U links in uranyl molybdates.

The uranyl influence on a mutation process in germ and somatic cells of mice

International Nuclear Information System (INIS)

Kostrova, L.N.; Mosseh, I.B.; Molofej, V.P.

2008-01-01

The mutagenic effect of uranyl was revealed by the chromosome rearrangement test in germ and somatic cells of mice. The effect value depended on duration of substance administration into organism. (authors)

Charge-density matching in organic-inorganic uranyl compounds

International Nuclear Information System (INIS)

Krivovichev, S.V.; Krivovichev, S.V.; Tananaev, I.G.; Myasoedov, B.F.

2007-01-01

Single crystals of [C 10 H 26 N 2 ][(UO 2 )(SeO 4 ) 2 (H 2 O)](H 2 SeO 4 ) 0.85 (H 2 O) 2 (1), [C 10 H 26 N 2 ][(UO 2 )(SeO 4 ) 2 ] (H 2 SeO 4 ) 0.50 (H 2 O) (2), and [C 8 H 20 N] 2 [(UO 2 )(SeO 4 ) 2 (H 2 O)] (H 2 O) (3) were prepared by evaporation from aqueous solution of uranyl nitrate, selenic acid and the respective amines. The structures of the compounds have been solved by direct methods and structural models have been obtained. The structures of the compounds 1, 2, and 3 contain U and Se atoms in pentagonal bipyramidal and tetrahedral coordinations, respectively. The UO 7 and SeO 4 polyhedra polymerize by sharing common O atoms to form chains (compound 1) or sheets (compounds 2 and 3). In the structure of 1, the layers consisting of hydrogen-bonded [UO 2 (SeO 4 ) 2 (H 2 O)] 2- chains are separated by mixed organic-inorganic layers comprising from [NH 3 (CH 2 ) 10 NH 3 ] 2+ molecules, H 2 O molecules, and disordered electroneutral (H 2 SeO 4 ) groups. The structure of 2 has a similar architecture but a purely inorganic layer is represented by a fully connected [UO 2 (SeO 4 ) 2 ] 2- sheet. The structure of 3 does not contain disordered (H 2 SeO 4 ) groups but is based upon alternating [UO 2 (SeO 4 ) 2 (H 2 O)] 2- sheets and 1.5-nm-thick organic blocks consisting of positively charged protonated octylamine molecules, [NH 3 (CH 2 ) 7 CH 3 ] + . The structures may be considered as composed of anionic inorganic sheets (2D blocks) and cationic organic blocks self-organized according to competing hydrophilic-hydrophobic interactions. Analysis of the structures allows us to conclude that the charge-density matching principle is observed in uranyl compounds. In order to satisfy some basic peculiarities of uranyl (in general, actinyl) chemistry, it requires specific additional mechanisms: (a) in long-chain-amine-templated compounds, protonated amine molecules inter-digitate; (b) in long-chain-diamine-templated compounds, incorporation of acid-water interlayers into

Behind adhesion of uranyl onto montmorillonite surface: A molecular dynamics study

Energy Technology Data Exchange (ETDEWEB)

Yang, W.; Zaoui, A., E-mail: azaoui@polytech-lille.fr

2013-10-15

Highlights: • We investigated the adsorption of uranyl onto Montmorillonite surface. • We studied the surface energy between layered Montmorillonite sheets. • We studied the work of adhesion between radionuclide and charged Montmorillonite. -- Abstract: We have performed molecular dynamics simulations to investigate the adsorption of radionuclide elements species onto substituted Montmorillonite (001) surface in the presence of different counterions. The structure and the dynamics of uranyl ion as well as its aquo, chloride ion, and carbonate complexes are analyzed. In addition, we have studied the surface energy between layered Montmorillonite sheets and the work of adhesion between radionuclide and charged Montmorillonite. The clay model used here is a Wyoming-type Montmorillonite with 0.75e negative charge per unit cell resulting from substitutions in Octahedral and Tetrahedral sheets. The system model was constructed based on CLAYFF force field potential model. To evaluate the thermodynamic work of adhesion, each surface and clay layer regions are converted to a thin film model. One and two species of radionuclide elements (UO{sub 2}(H{sub 2}O){sub 5},UO{sub 2}CO{sub 3}(H{sub 2}O){sub 5}, and UO{sub 2}Cl{sub 2}(H{sub 2}O){sub 5}) were deposited near the clay surface in a pseudo-two-dimensional periodic cell. Analysis shows that the uranyl ion structure is preserved with two axial oxygen atoms detected at 1.8 Å. Radial distribution functions results indicate that average U-O{sub w} distances are 2.45–2.61 Å, and 2.29–2.40 Å for U-O{sub c} distance. Average U-Cl distances are 2.78–3.08 Å, which is relatively larger than that of Uranium atom-Oxygen atom because of electrostatic factors.

A new uranyl phosphate sheet in the crystal structure of furongite

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Dal Bo, Fabrice; Hatert, Frederic [Liege Univ. (Belgium). Lab. de Mineralogie; Philippo, Simon [Musee National d' Historie Naturelle, Luxembourg (Luxembourg). Section Mineralogie

2017-06-15

The crystal structure of furongite, Al{sub 4}[(UO{sub 2}){sub 4}(PO{sub 4}){sub 6}](OH){sub 2}(H{sub 2}O){sub 19.5}, from the Kobokobo pegmatite, Kivu, Democratic Republic of Congo, was solved for the first time. Furongite is triclinic, the space group P anti 1, Z=2, a = 12.1685(8), b = 14.1579(6), c = 17.7884(6) Aa, α = 79.822(3), β = 77.637(4), γ = 67.293(2) , and V = 2746.2(2)Aa{sup 3}. The crystal structure was refined from single crystal X-ray diffraction data to R{sub 1} = 0.0733 for 7716 unique observed reflections, and to wR{sub 2} = 0.2081 for all 12,538 unique reflections. The structure of furongite contains infinite uranyl phosphate sheets of composition [(UO{sub 2}){sub 4}(PO{sub 4}){sub 6}]{sup 10-} which are parallel to (1 0 1). The sheets are constituted by UrO{sub 5} pentagonal bipyramids and PO{sub 4} tetrahedra which share edges and vertices, and adjacent sheets are linked by a dense network of hydrogen bonds. Running through the sheets and connected mainly to the free apical oxygen atom of PO4 tetrahedra are Al octahedra connected together to form remarkable Al{sub 2}O{sub 5}(OH)(H{sub 2}O){sub 5} and Al{sub 4}O{sub 8}(OH){sub 2}(H{sub 2}O){sub 10} clusters. These Al clusters are only bonded to one sheet, and do not connect two adjacent sheets together. The topology of the uranyl phosphate sheets is related to the uranophane anion topology, and can be described as a new geometrical isomer of the uranophane group. Furongite is the first uranyl phosphate reported in nature with a U:P ratio of 2:3.

Weathering of natural uranyl oxide hydrates: Schoepite polytypes and dehydration effects

International Nuclear Information System (INIS)

Finch, R.J.; Miller, M.L.; Ewing, R.C.

1992-01-01

Partial dehydration of schoepite, UO 3 x2H 2 O, is reported to produce three discrete schoepite polytypes with characteristic unit cell parameters, but this has not been confirmed. The loss of structural water from the schoepite interlayer results in progressive modification to the structure; expansion parallel to schoepite cleavage planes, and extensive fracturing. Dehydration of schoepite commences at grain boundaries and progresses inward until the entire grain is converted to dehydrated schoepite, UO 3 x0.8H 2 O. The volume decrease associated with dehydration results in expanded grain boundaries. These gaps can provide pathways for the access of groundwater, and uranyl silicates and uranyl carbonates have precipitated within these gaps, replacing both schoepite and dehydrated schoepite. Schoepite, however, is not observed to re-precipitate where in contact with dehydrated schoepite. Thus, while the formation of schoepite early during the corrosion of uraninite may be favored, schoepite is not a long-term solubility limiting phase for oxidized uranium in natural ground waters containing dissolved silica or carbonate. (orig.)

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.

f-Element Ion Chelation in Highly Basic Media

International Nuclear Information System (INIS)

Paine, R.T.

2000-01-01

A large body of data has been collected over the last fifty years on the chemical behavior of f-element ions. The ions undergo rapid hydrolysis reactions in neutral or basic aqueous solutions that produce poorly understood oxide-hydroxide species; therefore, most of the fundamental f-element solution chemistry has allowed synthetic and separations chemists to rationally design advanced organic chelating ligands useful for highly selective partitioning and separation of f-element ions from complex acidic solution matrices. These ligands and new examples under development allow for the safe use and treatment of solutions containing highly radioactive species. This DOE/EMSP project was undertaken to address the following fundamental objectives: (1) study the chemical speciation of Sr and lanthanide (Ln) ions in basic aqueous media containing classical counter anions found in waste matrices; (2) prepare pyridine N-oxide phosphonates and phosphonic acids that might act as selective chelators for Ln ions in model basic pH waste streams; (3) study the binding of the new chelators toward Ln ions and (4) examine the utility of the chelators as decontamination and dissolution agents under basic solution conditions. The project has been successful in attacking selected aspects of the very difficult problems associated with basic pH solution f-element waste chemistry. In particular, the project has (1) shed additional light on the initial stages of Ln ion sol-gel-precipitate formulation under basic solution conditions; (2) generated new families of pyridine phosphonic acid chelators; (3) characterized the function of the chelators and (4) examined their utility as oxide-hydroxide dissolution agents. These findings have contributed significantly to an improved understanding of the behavior of Ln ions in basic media containing anions found in typical waste sludges as well as to the development of sludge dissolution agents. The new chelating reagents are easily made and could be

Chelating agents as stationary phase in extraction chromatography, ch. 11

International Nuclear Information System (INIS)

Sebesta, F.

1975-01-01

Chelating agents have been used largely in extraction chromatography for separations related to activation analysis, for concentration of metals from dilute solutions, and for preparation of radiochemically pure or carrier-free radionuclides. This review deals with the theory of extraction by chelating agents, the experimental technique, and the chelating agents and systems used (β-diketones, oximes, hydroxamic acid, dithizone and diethyldithiocarbamic acid)

Topologically and geometrically flexible structural units in seven new organically templated uranyl selenates and selenite-selenates

Science.gov (United States)

Gurzhiy, Vladislav V.; Kovrugin, Vadim M.; Tyumentseva, Olga S.; Mikhaylenko, Pavel A.; Krivovichev, Sergey V.; Tananaev, Ivan G.

2015-09-01

Single crystals of seven novel uranyl oxysalts of selenium with protonated methylamine molecules, [C2H8N]2[(UO2)(SeO4)2(H2O)] (I), [C2H8N]2[(UO2)2(SeO4)3(H2O)] (II), [C4H15N3][H3O]0.5[(UO2)2(SeO4)2.93(SeO3)0.07(H2O)](NO3)0.5 (III), [C2H8N]3[H5O2][(UO2)2(SeO4)3(H2O)2]2(H2O)5 (IV), [C2H8N]2[H3O][(UO2)3(SeO4)4(HSeO3)(H2O)](H2SeO3)0.2 (V), [C4H12N]3[H3O][(UO2)3(SeO4)5(H2O)] (VI), and [C2H8N]3(C2H7N)[(UO2)3(SeO4)4(HSeO3)(H2O)] (VII) have been prepared by isothermal evaporation from aqueous solutions. Their crystal structures have been solved by direct methods and their uranyl selenate and selenite-selenate units investigated using black-and-white graphs from the viewpoints of topology of interpolyhedral linkages and isomeric variations. The crystal structure of IV is based upon complex layers with unique topology, which has not been observed previously in uranyl selenates. Investigations of the statistics and local distribution of the U-Obr-Se bond angles demonstrates that shorter angles associate with undulations, whereas larger angles correspond to planar areas of the uranyl selenite layers.

Impact of uranyl-calcium-carbonato complexes on uranium(VI) adsorption to synthetic and natural sediments.

Science.gov (United States)

Stewart, Brandy D; Mayes, Melanie A; Fendorf, Scott

2010-02-01

Adsorption on soil and sediment solids may decrease aqueous uranium concentrations and limit its propensity for migration in natural and contaminated settings. Uranium adsorption will be controlled in large part by its aqueous speciation, with a particular dependence on the presence of dissolved calcium and carbonate. Here we quantify the impact of uranyl speciation on adsorption to both goethite and sediments from the Hanford Clastic Dike and Oak Ridge Melton Branch Ridgetop formations. Hanford sediments were preconditioned with sodium acetate and acetic acid to remove carbonate grains, and Ca and carbonate were reintroduced at defined levels to provide a range of aqueous uranyl species. U(VI) adsorption is directly linked to UO(2)(2+) speciation, with the extent of retention decreasing with formation of ternary uranyl-calcium-carbonato species. Adsorption isotherms under the conditions studied are linear, and K(d) values decrease from 48 to 17 L kg(-1) for goethite, from 64 to 29 L kg (-1) for Hanford sediments, and from 95 to 51 L kg(-1) for Melton Branch sediments as the Ca concentration increases from 0 to 1 mM at pH 7. Our observations reveal that, in carbonate-bearing waters, neutral to slightly acidic pH values ( approximately 5) and limited dissolved calcium are optimal for uranium adsorption.

Structural determination of some uranyl compounds by vibrational spectroscopy

International Nuclear Information System (INIS)

Rodriguez S, A.; Martinez Q, E.

1990-07-01

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)

Modeling of critical experiments employing Raschig rings in uranyl nitrate solution

International Nuclear Information System (INIS)

Tanner, J.E.

1989-01-01

Four critical experiments employing borated glass rings in concentrated uranyl nitrate solution yielded k eff higher by 0. 04 when modeled with a flux-weighted, homogenized cross section set than when modeled with discrete rings. k eff varied by 0.014 for a 10% boron uncertainty and by up to 0.04 for a 10% packing fraction uncertainty

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

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Gurzhiy, Vladislav V., E-mail: vladgeo17@mail.ru [Department of Crystallography, St. Petersburg State University, University Emb. 7/9, 199034 St. Petersburg, Russia Federation (Russian Federation); Tyumentseva, Olga S.; Krivovichev, Sergey V. [Department of Crystallography, St. Petersburg State University, University Emb. 7/9, 199034 St. Petersburg, Russia Federation (Russian Federation); Tananaev, Ivan G. [Far Eastern Federal University, Suhanova st. 8, Vladivostok 690950 (Russian Federation)

2017-04-15

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 Cs{sub 2}[(UO{sub 2}){sub 2}(TO{sub 4}){sub 3}] (T= S, Se), which crystallizes in tetragonal system, P-42{sub 1}m, a =9.616(1)–9.856(2), c =8.105(1)–8.159(1) Å, V =749.6(2)–792.5(3) Å{sup 3}. Nine phases with variable amount of S and Se have been structurally characterized. The structures of the Cs{sub 2}[(UO{sub 2}){sub 2}(TO{sub 4}){sub 3}] (T= S, Se) compounds are based upon the [(UO{sub 2}){sub 2}(TO{sub 4}){sub 3}]{sup 2-} layers of corner-sharing uranyl pentagonal bipyramids and TO{sub 4} 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 S{sup 6+} cation showing a strong preference for the more tightly bonded T2 site. Crystallization in the pure Se system starts with the formation of Cs{sub 2}[(UO{sub 2})(SeO{sub 4}){sub 2}(H{sub 2}O)](H{sub 2}O) crystals, its subsequent dissolution and formation of Cs{sub 2}[(UO{sub 2}){sub 2}(SeO{sub 4}){sub 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. - Graphical abstract: Nine phases representing the Cs{sub 2}[(UO{sub 2}){sub 2}(TO{sub 4}){sub 3}] (T= S, Se) solid solution series with variable amount of S and Se have been prepared by isothermal evaporation from aqueous solutions and characterized using a number of experimental and theoretical techniques. No immiscibility is observed between the

The study of conjugation of anti-CD20 monoclonal antibody for labeling with metallic or lanthanides radionuclides; Estudo de conjugacao do anticorpo anti-CD20 para marcacao com radionuclideos metalicos ou lantanideos

Energy Technology Data Exchange (ETDEWEB)

Akanji, Akinkunmi Ganiyu

2012-07-01

Lymphomas are malignancies or cancers that start from the malign transformation of a lymphocyte in the lymphatic system. Generally, lymphomas start from the lymph nodes or from the agglomeration of the lymphatic tissues, organs like stomach, intestines, in some cases it can involve the bone marrow and the blood, it can also disseminate to other organs. Lymphomas are divided in two major categories: Hodgkin lymphoma and non-Hodgkin lymphoma (NHL). Patient with NHL are generally treated with radiotherapy alone or combined with immunotherapy using monoclonal antibody rituximab (MabThera Registered-Sign ). Currently, monoclonal antibodies (Acm) conjugated with bifunctional chelate agents and radiolabeled with metallic or lanthanides radionuclides are a treatment reality for patients with NHL by the principle of radioimmunotherapy (RIT). This study focused on the conditions of conjugation of Acm rituximab (MabThera Registered-Sign ) with bifunctional chelating agents DOTA and DTPA. Various parameters were studied: method of Acm purification, conditions of Acm conjugation, the method for determination of number of chelate agent coupled to the Acm, method for purification of the conjugated antibody Acm, conditions of labeling of the conjugated antibody with lutetium-177, method of purification of the radiolabeled immuno conjugate, method of radiochemical purity (RP), specific binding in vitro Raji cells (Human Burkitt) and biological distribution performed in normal Balb-c mouse. The three methodologies employed in pre-purification of Acm (dialysis, size exclusion chromatograph and dial filtration) demonstrated to be efficient; they provided sample recovery exceeding 90%. However, the methodology of dial filtration presents minimal sample loss, and gave the final recovery of the sample in micro liters; thereby facilitating sample use in subsequent experiments. Numbers of chelators attached to the Acm molecule was proportional to the molar ratio studied. When we evaluated

Application of membrane LaF3 electrode in the determination of stability constants of Uranyl Fluoride complex in solution

International Nuclear Information System (INIS)

Muzakky; Iswani GS; Mintolo

1996-01-01

A membrane electrode LaF 3 has been applied in the determination of uranyl fluoride complex stability constant in solution. The determination is based on the detection of free F ion in solution as a result of hydrolysis reaction (process) of uranyl ions into the uranyl hydroxide form at low pH. The experiment results showed that there was no effect of ammonium carbonate 2 M titran, flow rate on the electrode response. The F release is optimum at pH 1. The free F ion in solution is calculated from the standard curve at pH 1, after the fluoride concentration at the same pH has been corrected. Using the plot of average number of ligand binding (n) versus minus log of free ligand (-log F) the value of β1 = 4.4, β2 = 7.48, β3=9.73, and β4 = 11.67

Thermometric titration of a free acid and of uranyl in spent fuel element solutions

International Nuclear Information System (INIS)

Zamek, M.; Strafelda, F.

1975-01-01

A method was elaborated of determining nitric acid in the presence of uranyl nitrate in both aqueous and non-aqueous solutions using a pyridine aqueous solution as a titration agent, and of determining excess uranyl after a hydrogen peroxide addition by a further titration using the same agent. Even a hundred-fold excess of magnesium did not disturb the titration. The method is used in operating solution analyses in the extraction fuel reprocessing in the presence of a small amount of plutonium and of fission products. The reproducibility and accuracy of the method varied in the order of tens to units per cent depending on the concentration of components to be determined. The procedure is applicable for test volumes ranging between 0.1 and 10 ml in concentrations of 1 to 10 -3 M. (author)

The adsorption of chelating reagents on oxide minerals

International Nuclear Information System (INIS)

Bryson, M.A.W.

1984-06-01

This work constitutes a fundamental study of the interaction between chelating reagents and oxide minerals. The adsorption mechanisms have been elucidated for most of the systems generated by the oxides of copper(II) or iron(III) and chelating reagents octyl hydroxamate, N-phenylbenzohydroxamate, salicylaldoxime, 5-nitro-salicylaldoxime or 8-hydroxyquinoline. In order to better understand the adsorption process associated with copper(II) oxide, the oxide was recrystallized to produce a coarser material with a more uniform surface. This allowed the oxide surface to be viewed under the scanning electron microscope. A detailed investigation of the effect of the system variables; pH, conditioning period, concentration, temperature, surface area and dispersing reagent on the rate of precipitation of the copper chelate species of general form, Cu(chel) 2 , was made. In addition the chemical nature of the adsorbed species and the structural form of the precipitates were determined with the aid of infra-red spectroscopy and the scanning electron microscope. On the basis of these results a model has been formulated for the adsorption processes. The precipitation process was examined in more detail by the study of the adsorption of chelate on copper metal. Contact angle measurements of air bubbles on copper metal conditioned with chelate were related to the adsorption results in an attempt to isolate the optimum conditions for flotation of oxide minerals

Interfacial Interaction of Titania Nanoparticles and Ligated Uranyl Species: A Relativistic DFT Investigation.

Science.gov (United States)

Zhao, Hong-Bo; Zheng, Ming; Schreckenbach, Georg; Pan, Qing-Jiang

2017-03-06

To understand interfacial behavior of actinides adsorbed onto mineral surfaces and unravel their structure-property relationship, the structures, electronic properties, and energetics of various ligated uranyl species adsorbed onto TiO 2 surface nanoparticle clusters (SNCs) were examined using relativistic density functional theory. Rutile (110) and anatase (101) titania surfaces, experimentally known to be stable, were fully optimized. For the former, models studied include clean and water-free Ti 27 O 64 H 20 (dry), partially hydrated (Ti 27 O 64 H 20 )(H 2 O) 8 (sol) and proton-saturated [(Ti 27 O 64 H 20 )(H 2 O) 8 (H) 2 ] 2+ (sat), while defect-free and defected anatase SNCs involving more than 38 TiO 2 units were considered. The aquouranyl sorption onto rutile SNCs is energetically preferred, with interaction energies of -8.54, -10.36, and -2.39 eV, respectively. Energy decomposition demonstrates that the sorption is dominated by orbital attractive interactions and modified by steric effects. Greater hydrogen-bonding involvement leads to increased orbital interactions (i.e., more negative energy) from dry to sol/sat complexes, while much larger steric interaction in the sat complex significantly reduces the sorption interaction (i.e., more positive energy). For dry SNC, adsorbates were varied from aquo to aquo-carbonato, to carbonato, to hydroxo uranyl species. Longer U-O surf /U-Ti distances and more positive sorption energies were calculated upon introducing carbonato and hydroxo ligands, indicative of weaker uranyl sorption onto the substrate. This is consistent with experimental observations that the uranyl sorption rate decreases upon raising solution pH value or adding carbon dioxide. Anatase SNCs adsorbing aquouranyl are even more exothermic, because more bonds are formed than in the case of rutile. Moreover, the anatase sorption can be tuned by surface defects as well as its Ti and O stoichiometry. All the aquouranyl-SNC complexes show similar

Labelling of bacteria with indium chelates

International Nuclear Information System (INIS)

Kleinert, P.; Pfister, W.; Endert, G.; Sproessig, M.

1985-01-01

The indium chelates were prepared by reaction of radioactive indiumchloride with 10 μg oxine, 15 μg tropolone and 3 mg acetylacetone, resp. The formed chelates have been incubated with 10 9 germs/ml for 5 minutes, with labelling outputs from 90 to 95%. Both gram-positive (Streptococcus, Staphylococcus) and gram-negative bacteria (Escherichia coli) can be labelled. The reproductive capacity of the bacteria was not impaired. The application of indium labelled bacteria allows to show the distribution of microorganisms within the living organism and to investigate problems of bacterial adherence. (author)

Uranium (VI) chemistry at the interface solution/minerals (quartz and aluminium hydroxide): experiments and spectroscopic investigations of the uranyl surface species; Chimie de l'uranium (VI) a l'interface solution/mineraux (quartz et hydroxyde d'aluminium): experiences et caracterisations spectroscopiques

Energy Technology Data Exchange (ETDEWEB)

Froideval, A.

2004-09-15

This study deals with the understanding of the uranyl chemistry at the 0.1 M NaNO{sub 3} solution/mineral (quartz and aluminium hydroxide) interface. The aims are:(i) to identify and to characterize the different uranyl surface species (mononuclear, polynuclear complexes and/or precipitates...), i.e. the coordination environments of sorbed/precipitated uranyl ions, by using X-ray photoelectron spectroscopy (XPS), extended X-ray absorption fine structure (EXAFS) and time-resolved laser-induced fluorescence spectroscopy (TRLFS), and;(ii) to investigate the influence of pH, initial uranyl aqueous concentration and hydroxyl ligand concentration on the uranyl surface speciation. Our study on the speciation of uranyl ions at the quartz surface (i) confirms the formation of uranyl polynuclear/oligomers on quartz from moderate (1 {mu}mol/m{sup 2}) to high (26 {mu}mol/m{sup 2}) uranyl surface concentrations and (ii) show that theses polynuclear species coexist with uranyl mononuclear surface species over a pH range {approx_equal} 5-8.5 and a wide range of initial uranyl concentration o f the solutions (10-100 {mu}M). The uranyl concentration of these surface species depends on pH and on the initial uranyl aqueous concentration. Hydrate (surface-) precipitates and/or adsorbed polynuclear species and monomeric uranyl surface complexes are formed on aluminium hydroxide. Uranyl mononuclear complexes are predominant at acidic pH, as well as uranyl in solution or on the surface. Besides mononuclear species, precipitates and/or adsorbed polynuclear species are predominantly formed at neutral pH values on aluminium hydroxide. A main contribution of our investigations is that precipitation and/or adsorption of polynuclear species seem to occur at low uranyl surface concentrations (0.01-0.4 {mu}mol/m{sup 2}). The uranyl surface speciation is mainly dependent on the pH and the aluminol ligand concentration. (author)

Subtle interactions and electron transfer between UIII, NpIII, or PuIII and uranyl mediated by the oxo group

International Nuclear Information System (INIS)

Arnold, Polly L.; Zegke, Markus; Hollis, Emmalina; Pecharman, Anne-Frederique; Love, Jason B.; Dutkiewicz, Michal S.; Walter, Olaf; Apostolidis, Christos; Magnani, Nicola; Griveau, Jean-Christophe; Colineau, Eric; Caciuffo, Roberto; Zhang, Xiaobin; Schreckenbach, Georg

2016-01-01

A dramatic difference in the ability of the reducing An III center in AnCp 3 (An=U, Np, Pu; Cp=C 5 H 5 ) to oxo-bind and reduce the uranyl(VI) dication in the complex [(UO 2 )(THF)(H 2 L)] (L=''Pacman'' Schiff-base polypyrrolic macrocycle), is found and explained. These are the first selective functionalizations of the uranyl oxo by another actinide cation. At-first contradictory electronic structural data are explained by combining theory and experiment. Complete one-electron transfer from Cp 3 U forms the U IV -uranyl(V) compound that behaves as a U V -localized single molecule magnet below 4 K. The extent of reduction by the Cp 3 Np group upon oxo-coordination is much less, with a Np III -uranyl(VI) dative bond assigned. Solution NMR and NIR spectroscopy suggest Np IV U V but single-crystal X-ray diffraction and SQUID magnetometry suggest a Np III -U VI assignment. DFT-calculated Hirshfeld charge and spin density analyses suggest half an electron has transferred, and these explain the strongly shifted NMR spectra by spin density contributions at the hydrogen nuclei. The Pu III -U VI interaction is too weak to be observed in THF solvent, in agreement with calculated predictions. (copyright 2016 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim)

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)

Uranyl ion complexation by the tripodal ligand nitrilo-tri-acetate

Energy Technology Data Exchange (ETDEWEB)

Thuery, P. [CEA Saclay, DSM/DRECAM/SCM, F-91191 Gif Sur Yvette, (France)

2007-07-01

Reaction of uranyl nitrate with N-(2-acetamido)iminodiacetic acid (ADA) under hydrothermal conditions resulted in the hydrolysis of the amide group and the isolation of the complex [(UO{sub 2})(HNTA)(H{sub 2}O){sub 2}], in which each nitrilo-tri-acetate ligand, protonated at the N site, bridges three metal atoms to give rise to infinite ladder-like ribbons built from 2:2 metallacycles. (author)

Investigation of Uranyl Nitrate Ion Pairs Complexed with Amide Ligands using Electrospray Ionization Ion Trap Mass Spectrometry and Density Functional Theory

International Nuclear Information System (INIS)

Groenewold, Gary S.; Dinescu, Adriana; Benson, Michael T.; Gresham, Garold L.; van Stipdonk, Michael J.

2011-01-01

Ion populations formed from electrospray of uranyl nitrate solutions containing different amides vary depending on ligand nucleophilicity and steric crowding at the metal center. The most abundant species were ion pair complexes having the general formula (UO2(NO3)(amide)n=2,3)+, and complexes containing the amide conjugate base, reduced uranyl UO2+, and a 2+ charge were also formed. The formamide experiment produced the greatest diversity of species that stems from weaker amide binding leading to dissociation and subsequent solvent coordination or metal reduction. Experiments using methyl formamide, dimethyl formamide, acetamide, and methyl acetamide produced ion pair and doubly charged complexes that were more abundant, and less abundant complexes containing solvent or reduced uranyl. This pattern is reversed in the dimethylacetamide experiment, which displayed reduced doubly charged complexes and augmented reduced uranyl complexes. DFT investigations of the tris-amide ion pair complexes showed that inter-ligand repulsion distorts the amide ligands out of the uranyl equatorial plane, and that complex stabilities do not increase with increasing amide nucleophilicity. Elimination of an amide ligand largely relieves the interligand repulsion, and the remaining amide ligands become closely aligned with the equatorial plane in the structures of the bis-amide ligands. The studies show that the phenomenological distribution of coordination complexes in a metal-ligand electrospray experiment is a function of both ligand nucleophilicity and interligand repulsion, and that the latter factor begins exerting influence even in the case of relatively small ligands like the substituted methyl-formamide and methyl-acetamide ligands.

Review of actinide decorporation with chelating agents

Energy Technology Data Exchange (ETDEWEB)

Ansoborlo, E. [CEA Valrho, Dir. de l' Energie Nucleaire (DEN/DRCP/CETAMA), 30 - Marcoule (France); Amekraz, B.; Moulin, Ch. [CEA Saclay, Dept. de Physico-Chimie (DEN/DPC/SECR), 91 - Gif sur Yvette (France); Moulin, V. [CEA Saclay, Dir. du Developpement et de l' Innovation Nucleares (DEN/DDIN/MR), 91 - Gif Sur Yvette (France); Taran, F. [CEA Saclay (DSV/DBJC/SMMCB), 91 - Gif-sur-Yvette (France); Bailly, Th.; Burgada, R. [Centre National de la Recherche Scientifique (CNRS/LCSB/UMR 7033), 93 - Bobigny (France); Henge-Napoli, M.H. [CEA Valrho, Site de Marcoule (INSTN), 30 (France); Jeanson, A.; Den Auwer, Ch.; Bonin, L.; Moisy, Ph. [CEA Valrho, Dir. de l' Energie Nucleaire (DEN/DRCP/SCPS), 30 - Marcoule (France)

2007-10-15

In case of accidental release of radionuclides in a nuclear facility or in the environment, internal contamination (inhalation, ingestion or wound) with actinides represents a severe health risk to human beings. It is therefore important to provide effective chelation therapy or decorporation to reduce acute radiation damage, chemical toxicity, and late radiation effects. Speciation governs bioavailability and toxicity of elements and it is a prerequisite tool for the design and success of new ligands or chelating agents. The purpose of this review is to present the state-of-the-art of actinide decorporation within biological media, to recall briefly actinide metabolism, to list the basic constraints of actinide-ligand for development, to describe main tools developed and used for decorporation studies, to review mainly the chelating agents tested for actinides, and finally to conclude on the future trends in this field. (authors)

Radiopharmaceutical chelates and method of external imaging

International Nuclear Information System (INIS)

1976-01-01

The preparation of the following chemicals is described: chelates of technetium-99m, cobalt-57, gallium-67, gallium-68, indium-111 or indium-113m and a substituted iminodiacetic acid or an 8-hydroxyquinoline useful as a radiopharmaceutical external imaging agent. The compounds described are suitable for intravenous injection, have an excellent in vivo stability and are good organ seekers. Tin(II) choride or other tin(II) compounds are used as chelating agents

Crystal structure of the (REE)–uranyl carbonate mineral shabaite-(Nd)

Czech Academy of Sciences Publication Activity Database

Plášil, Jakub; Škoda, R.

2017-01-01

Roč. 62, č. 2 (2017), s. 97-105 ISSN 1802-6222 R&D Projects: GA MŠk LO1603 EU Projects: European Commission(XE) CZ.2.16/3.1.00/24510 Institutional support: RVO:68378271 Keywords : shabaite-(Nd) * uranyl carbonate * rare-earth elements * crystal structure * mineral evolution Subject RIV: DB - Geology ; Mineralogy OBOR OECD: Geology Impact factor: 0.609, year: 2016

Recuperation of uranyl ions from effluents by means of microbiological collectors

International Nuclear Information System (INIS)

Cecal, A.; Palamaru, I.; Humelnicu, D.; Goanta, M.; Rudic, V.; Salaru, V.V.; Gulea, A.

1997-01-01

This paper deals with the study of bioaccumulation of uranyl ions (UO 2 2+ ) from industrial effluents, using microbiological collectors: Nostoc linkia sp., Tolipotrix sp., Spirulina sp., Porphyridium cruentum and also the glucide extract of P. cruentum. The values of retaining degree of UO 2 2+ on the biomass, for several experimental conditions, were established between 14.22 and 91.99%

Complexes of uranyl with N-oxides of heterocyclic amines. Electron-vibrational absorption spectra

International Nuclear Information System (INIS)

Jezowska-Trzebiatowska, B.; Wieczorek, M.

1977-01-01

A number of coordination compounds formed by uranyl chloride and nitrate with N-oxides of heterocyclic amines have been prepared and characterized by spectral measurements in the absorption region 20000-50000 cm -1 . The electrons and vibronic transitions have been determined and discussed. (author)

Radioimmunoimaging in malignant melanoma with 111In-labeled monoclonal antibody 96.5

International Nuclear Information System (INIS)

Murray, J.L.; Rosenblum, M.G.; Sobol, R.E.

1985-01-01

A radiolabeled monoclonal antibody (96.5) reactive with an Mr 97,000 antigen found on over 80% of melanoma cell lines and tissue extracts was examined for its ability to detect malignant melanoma metastases in vivo. For imaging purposes, it was conjugated with diethyltriaminepentaacetic acid and subsequently labeled with 111 In by chelation. Thirty-one patients with metastatic melanoma received single injections of monoclonal antibody 96.5 at concentrations ranging from 0.5 to 20 mg and at specific activities of 111 In ranging from 0.125 to 4 mCi/mg. Total-body scans were performed at various time intervals following administration. No serious side effects were observed. Of a total of 100 previously documented metastatic sites, 50 imaged for a specificity of 50%. The number of sites imaged increased significantly as the amount of antibody administered increased relative to the average radiation dose. Considerable background uptake of isotope was observed in blood pool and other organs with gradual acquisition of label in tumor sites by 48 to 72 h. Hence, tumor imaging of melanoma using 111 In-labeled monoclonal antibody 96.5 appeared feasible, especially at antibody doses above 2 mg

Modulation of the unpaired spin localization in Pentavalent Uranyl Complexes

Energy Technology Data Exchange (ETDEWEB)

Vetere, V.; Maldivi, P.; Mazzanti, M. [CEA Grenoble, INAC, SCIB, laboratoire de reconnaissance ionique et chimie de coordination, 38 (France); Vetere, V. [UMR5626, laboratoire de chimie et physique quantique, universite de Toulouse, 31 - Toulouse (France)

2010-06-15

The electronic structure of various complexes of pentavalent uranyl species, namely UO{sub 2}{sup +}, is described, using DFT methods, with the aim of understanding how the structure of the ligands may influence the localisation of the unpaired 5f electron of uranium (V) and, finally, the stability of such complexes towards oxidation. Six complexes have been inspected: [UO{sub 2}py{sub 5}]{sup +} (1), [(UO{sub 2}py{sub 5})KI{sub 2}] (2), [UO{sub 2}(salan-{sup t}Bu{sub 2})(py)K] (3), [UO{sub 2}(salophen-{sup t}Bu{sub 2})(thf)K] (4), [UO{sub 2}(salen-{sup t}Bu{sub 2})(py)K] (5), [and UO{sub 2}-cyclo[6]pyrrole]{sup 1-} (6), chosen to explore various ligands. In the five first complexes, the UO{sub 2}{sup +} species is well identified with the unpaired electron localized on the 5f uranium orbital. Additionally, for the salan, salen and salophen ligands, some covalent interactions have been observed, resulting from the presence of both donor and acceptor binding sites. In contrast, the last complex is best described by a UO{sub 2}{sup 2+} uranyl (VI) coordinated by the anionic radical cyclo-pyrrole, the highly delocalized p orbitals set stabilizing the radical behaviour of this ligand. (authors)

Mechanistic study of the interaction of uranyl ions with zirconium oxide and zirconium silicate

International Nuclear Information System (INIS)

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 4 or KNO 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 (≡Zr-O- on zirconia and ≡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)

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

Phenolic aminocarboxylic acids - new chelating agents for modifying gallium-67 biodistribution

Energy Technology Data Exchange (ETDEWEB)

Hunt, F.C.; Maddalena, D.J. (Australian Atomic Energy Commission Research Establishment, Lucas Heights)

The chelating agents EDDHA and HBED were synthesised with carboxyl or sulphonyl groups in the phenolic ring to favour urinary excretion on complexing with gallium. Carboxyl EDDMA was administered to tumor-bearing rats, and its concentration in the tumours and other tissues determined by scintigraphic imaging. The chelating agents increase tumour to blood ratios by chelating gallium in vivo.

Combinational chelation therapy abrogates lead-induced neurodegeneration in rats

International Nuclear Information System (INIS)

Pachauri, Vidhu; Saxena, Geetu; Mehta, Ashish; Mishra, Deepshikha; Flora, Swaran J.S.

2009-01-01

Lead, a ubiquitous and potent neurotoxicant causes oxidative stress which leads to numerous neurobehavioral and physiological alterations. The ability of lead to bind sulfhydryl groups or compete with calcium could be one of the reasons for its debilitating effects. In the present study, we addressed: i) if chelation therapy could circumvent the altered oxidative stress and prevent neuronal apoptosis in chronic lead-intoxicated rats, ii) whether chelation therapy could reverse biochemical and behavioral changes, and iii) if mono or combinational therapy with captopril (an antioxidant) and thiol chelating agents (DMSA/MiADMSA) is more effective than individual thiol chelator in lead-exposed rats. Results indicated that lead caused a significant increase in reactive oxygen species, nitric oxide, and intracellular free calcium levels along with altered behavioral abnormalities in locomotor activity, exploratory behavior, learning, and memory that were supported by changes in neurotransmitter levels. A fall in membrane potential, release of cytochrome c, and DNA damage indicated mitochondrial-dependent apoptosis. Most of these alterations showed significant recovery following combined therapy with captopril with MiADMSA and to a smaller extend with captopril + DMSA over monotherapy with these chelators. It could be concluded from our present results that co-administration of a potent antioxidant (like captopril) might be a better treatment protocol than monotherapy to counter lead-induced oxidative stress. The major highlight of the work is an interesting experimental evidence of the efficacy of combinational therapy using an antioxidant with a thiol chelator in reversing neurological dystrophy caused due to chronic lead exposure in rats.

Synthesis and X-ray diffraction study of new uranyl malonate and oxalate complexes with carbamide

International Nuclear Information System (INIS)

Medvedkov, Ya. A.; Serezhkina, L. B.; Grigor’ev, M. S.; Serezhkin, V. N.

2016-01-01

Two new malonate-containing uranyl complexes with carbamide of the formulas [UO 2 (C 3 H 2 O 4 )(Urea) 2 ] (I) and [UO 2 (C 3 H 2 O 4 )(Urea) 3 ] (II), where Urea is carbamide, and one uranyl oxalate complex of the formula [UO 2 (C 2 O 4 )(Urea) 3 ] (III) were synthesized, and their crystals were studied by X-ray diffraction. The main structural units in crystals I are the electroneutral chains [UO 2 (C 3 H 2 O 4 )(Urea) 2 ] ∞ belonging to the crystal-chemical group AT 11 M 2 1 (A = UO 2 2+ , T 11 = C 3 H 2 O 4 2- , M 1 = Urea) of uranyl complexes. Crystals II and III are composed of the molecular complexes [UO 2 (L)(Urea) 3 ], where L = C 3 H 2 O 4 2- or C 2 O 4 2- , belonging to the crystal-chemical group AB 01 M 3 1 (A = UO 2 2+ , B 01 = C 3 H 2 O 4 2- or C 2 O 4 2- , M 1 = Urea). The characteristic features of the packing of the uranium-containing complexes are discussed in terms of molecular Voronoi–Dirichlet polyhedra. The effect of the Urea: U ratio on the structure of uranium-containing structural units is considered.

Rates of cuticular penetration of chelated Fe(III): role of humidity, concentration, adjuvants, temperature, and type of chelate.

Science.gov (United States)

Schönherr, Jörg; Fernández, Victoria; Schreiber, Lukas

2005-06-01

Time courses of cuticular penetration of FeCl3 and Fe(III) complexes of citric acid, EDTA, EDDHA (Sequestrene 138Fe), imidodisuccinic acid (IDHA), and ligninsulfonic acid (Natrel) were studied using astomatous cuticular membranes (CMs) isolated from Populus x canescens leaves. At 100% relative humidity, the Fe(III) chelates disappeared exponentially with time from the surface of the CMs; that is, penetration was a first-order process that can be described using rate constants or half-times of penetration (t(1/2)). Half-times ranged from 20 to 30 h. At 90% humidity, penetration rates were insignificant with the exception of Natrel, for which t(1/2) amounted to 58 h. Rate constants were independent of temperature (15, 25, and 35 degrees C). Permeability decreased with increasing Fe chelate concentration (IDHA and EDTA). At 100% humidity, half-times measured with FeIDHA were 11 h (2 mmol L(-1)), 17 h (10 mmol L(-1)) and 36 h (20 mmol L(-1)), respectively. In the presence of FeEDTA, penetration of CaCl2 was slowed greatly. Half-times for penetration of CaCl2, which were 1.9 h in the absence of FeEDTA, rose to 3.12 h in the presence of an equimolar concentration of EDTA and 13.3 h when the FeEDTA concentration was doubled. Hence, Fe chelates reduced permeability of CMs to CaCl2 and to the Fe chelates themselves. It is suggested that Fe chelates reduced the size of aqueous pores. This view is supported by the fact that rate constants for calcium salts were about 5 times higher than for Fe chelates with the same molecular weights. Adding Tween 20 (5 g L(-1)) as a humectant did not increase permeability to FeIDHA at 90% humidity and below, while addition of glycine betaine did. Penetration of FeCl3 applied at 5 g L(-1) (pH 1.5) was not a first order process as rate constants decreased rapidly with time. Only 2% of the dose penetrated during the first 2 h and less than that in the subsequent 8 h. Recovery was only 70%. This was attributed to the formation of insoluble Fe

Uranyl determination using pyridylazoresorcinol as complexing active by adsorb voltametry technique with cathodic redissolution

International Nuclear Information System (INIS)

Ohara, A.K.; Farias, P.A.M.

1990-01-01

The development method for uranyl ion determination by the optimization of chemical reaction and instrumental parameters is shown. This method is based on preconcentration stage, where in adsorptive accumulation of metallic complex in a static electrode is presented. (author)

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

Effect of diluent on extraction of uranyl nitrate from nitric acid solution by tri-n-octylamine

International Nuclear Information System (INIS)

Kojima, Takashi; Ukon, Toshiaki; Fukutomi, Hiroshi

1979-01-01

The distribution ratios in the extraction equilibriums of uranylnitrate from 3 M HNO 3 by tri-n-octylamine (TOA) nitrate salt in nitrobenzene, chlorobenzene, benzene, toluene, cyclohexane, nitrobenzene-benzene and benzene-cylohexane mixtures have been determined in varying the concentrations of uranyl nitrate and TOA nitrate salt. The extraction mechanisms have been discussed in detail based on the law of mass action. It has been concluded that the extractions of uranyl nitrate by TOA nitrate salt in nitrobenzene, 74% nitrobenzene-benzene and 49% nitrobenzene-benzene mixture are represented by the equation TOAHNO 3 (org) + UO 2 2+ (aq) + 2 NO 3 - (aq) = TOAHUO 2 (NO 3 - ) 3 (org), while the extractions of uranyl nitrate by TOA nitrate salt in chlorobenzene, benzene, toluene, cyclohexane, benzene-cyclohexane mixtures and 24% nitrobenzene-benzene mixture are represented by the equation 2 TOAHNO 3 (org) + UO 2 2+ (aq) + 2 NO 3 - (aq) = TOAHUO 2 (NO 3 ) 3 TOAHNO 3 (org). In the latter the extraction equilibrium constants increase in the order of chlorobenzene < benzene < toluene < cyclohexane and with decreasing of the volume fraction of benzene in benzene-cyclohexane mixtures. The effects of diluent have been discussed in detail on the basis of the Hildebrand-Scatchard theory of regular solutions. (author)

Mixed and chelated waste test programs with bitumen solidification

International Nuclear Information System (INIS)

Simpson, S.I.; Morris, M.; Vidal, H.

1988-01-01

This paper presents the results of bitumen solidification tests on mixed wastes and chelated wastes. The French Atomic Energy Commission (CEA) performed demonstration tests on radioactive wastes contaminated with chelating agents for Associated Technologies, Inc. (ATI). The chelated wastes were produced and concentrated by Commonwealth Edison Co. as a result of reactor decontamination at Dresden Nuclear Station, Unit 1. Law Engineering in Charlotte, N. C. produced samples and performed tests on simulated heavy metal laden radioactive waste (mixed) to demonstrate the quality of the bituminous product. The simulation is intended to represent waste produced at Oak Ridge National Labs operated by Martin-Marietta

Efficient tetracycline adsorption and photocatalytic degradation of rhodamine B by uranyl coordination polymer

Science.gov (United States)

Ren, Ya-Nan; Xu, Wei; Zhou, Lin-Xia; Zheng, Yue-Qing

2017-07-01

Two mixed uranyl-cadmium malonate coordination polymers [(UO2)2Cd(H-bipy)2(mal)4(H2O)2]·4H2O 1 and [(UO2)Cd(bipy)(mal)2]·H2O 2 (H2mal = malonic acid, bipy =4,4‧-bipyridine) have been synthesized in room temperature. Compound 1 represents a one-dimensional (1D) chain assembly of Cd(II) ions, uranyl centers and malonate ligands. Compound 2 exhibits a two-dimensional (2D) 2D +2D → 3D polycatenated framework based on inclined interlocked 2D 44 sql grids. The two compounds have been characterized by elemental analysis, IR and UV-vis spectroscopy, thermal analysis, powder X-ray diffraction and photoluminescence spectroscopy. And the ferroelectric property of 2 also has been studied. Moreover, compound 2 exhibits good photocatalytic activity for dye degradation under UV light and is excellent adsorbent for removing tetracycline antibiotics in the aqueous solution.

Effect of Chelator Conjugation Level and Injection Dose on Tumor and Organ Uptake of 111In Labeled MORAb-009, an Anti-mesothelin Antibody

Science.gov (United States)

Shin, I. S.; Lee, S.-M.; Kim, H. S.; Yao, Z.; Regino, C.; Sato, N.; Cheng, K. T.; Hassan, R.; Campo, M. F.; Albone, E. F.; Choyke, P. L.; Pastan, I.; Paik, C. H.

2012-01-01

Introduction Radiolabeling of a monoclonal antibody (mAb) with a metallic radionuclide requires the conjugation of a bifunctional chelator to the mAb. The conjugation, however, can alter the physical and immunological properties of the mAb, consequently affecting its tumor targeting pharmacokinetics. In this study, we investigated the effect of the amount of 2-(p-isothiocyanatobenzyl)-cyclohexyl-diethylenetriamine-pentaacetic acid (CHX-A″) conjugated to MORAb-009, a mAb directed against mesothelin and the effect of MORAb dose on the biodistribution of 111In labeled MORAb-009. Methods We used nude mice bearing A431/K5 tumor as a mesothelin-positive tumor model and A431 tumor as a mesothelin-negative control. To find the optimal level of CHX-A″ conjugation, CHX-A″-MORAb-009 conjugates with 2.4, 3.5, and 5.5 CHX-A″ molecules were investigated. To investigate the effect of injected MORAb-009 dose on neutralizing the shed-mesothelin in the circulation, the biodistribution studies were performed after the i.v. co-injection of the 111In labeled MORAb-009 (2.4 CHX-A″/MORAb-009) with three different doses, 0.2, 2, and 30 μg of MORAb-009. Results The tumor uptake in A431/K5 tumor was 4 times higher than that in A431 tumor, indicating that the tumor uptake in A431/K5 was mesothelin-mediated. The conjugate with 5.5 CHX-A″ showed a lower isoelectric point (pI) and lower immunoreactivity (IR) than the 2.4 CHX-A″ conjugate. These differences were reflected in biodistribution of the 111In label. The 111In labeled MORAb-009 conjugated with 2.4 CHX-A″ produced higher tumor uptake, and lower liver and spleen uptakes than the 5.5 CHX-A″ conjugate. The biodistribution studies also revealed that the tumor uptake was significantly affected by the injected MORAb-009 dose and tumor size. The 30 μg dose produced higher tumor uptake than the 0.2 and 2 μg doses whereas the 30 μg dose produced lower liver and spleen uptakes than the 0.2 μg dose. Conclusion This study

Uranyl-organic assemblies with the macrocyclic ligand 1, 4, 8, 11-tetra-aza-cyclo-tetradecane-1, 4, 8, 11-tetraacetate (TETA)

International Nuclear Information System (INIS)

Thuery, Pierre

2010-01-01

Three uranyl ion complexes obtained from the reaction of uranyl nitrate hexahydrate and 1, 4, 8, 11-tetra-aza-cyclo-tetradecane-1, 4, 8, 11-tetraacetic acid (H 4 TETA) were characterized by their crystal structure. The centrosymmetric macrocycle, in the [3434] conformation with either carbon or nitrogen atoms as corners, is zwitterionic, with four carboxylate groups and two or four protonated nitrogen atoms. The complexes [(UO 2 ) 2 (H 2 TETA)(C 2 O 4 )(H 2 O) 2 ] (1) and [UO 2 (H 4 TETA)(H 2 O)].NO 3 .Cl (2) were synthesized under hydrothermal conditions and 1 includes additional oxalate ligands generated in situ. Both compounds are two-dimensional polymers in which the four-fold monodentate macrocyclic ligand unites either four uranyl oxalate dinuclear species (1) or isolated uranyl ions (2). Complex 3, [UO 2 (H 2 TETA)(H 2 O)].6H 2 O, was obtained at room temperature and, although it displays the same stoichiometry as 2, it differs from it by being a three-dimensional framework. Both 2 and 3 present channels containing either counter-ions or water molecules. As often observed, the water content of the low-temperature species, 3, is higher than that of the high-temperature one, 2. (author)

Different photoluminescent properties of binary and ternary europium chelates doped in PMMA

International Nuclear Information System (INIS)

Liu Hongguo; Park, Seongtae; Jang, Kiwan; Zhang Wansong; Seo, Hyo-Jin; Lee, Yong-Ill

2003-01-01

Two kinds of europium-β-diketone chelates, binary Eu(DBM) 3 and ternary Eu(DBM) 3 phen were doped in poly(methyl methacrylate) (PMMA). These chelates show very different photoluminescent (PL) behaviors: the hypersensitive 5 D 0 → 7 F 2 emission bands of Eu(DBM) 3 phen change slightly with the molar ratios, while those of Eu(DBM) 3 change obviously and regularly with the molar ratios. The results of the luminescent lifetimes of 5 D 0 levels show that the binary chelate exists as two kinds of species in the doped systems, and the lifetimes and contents of each species change with the molar ratios, while the ternary chelate exists as one kind of species in the doped systems. X-ray diffraction (XRD) patterns of the binary chelate doped systems give some diffraction peaks that are different from those of pure chelate and change with the molar ratios, indicating new kinds of crystal structures formed, and consequently, the first coordination sphere of Eu 3+ ion changes; while those of the ternary chelate doped systems just show amorphous diffraction halos of the host, indicating that the ternary chelate exist in an amorphous state and disperse well in the host. The FTIR spectra of PMMA also change gradually with increasing the molar ratios of the doped two kinds of chelates, and the XRD patterns show that the amorphous halos of PMMA in the doped systems are different from those of pure PMMA and change with the molar ratios, too, suggesting the interaction between the guest and the host

Phenolic aminocarboxylic acids - new chelating agents for modifying gallium-67 biodistribution

International Nuclear Information System (INIS)

Hunt, F.C.; Maddalena, D.J.

1982-01-01

The chelating agents EDDHA and HBED were synthesised with carboxyl or sulphonyl groups in the phenolic ring to favour urinary excretion on complexing with gallium. Carboxyl EDDMA was administered to tumor-bearing rats, and its concentration in the tumours and other tissues determined by scintigraphic imaging. The chelating agents increase tumour to blood ratios by chelating gallium in vivo. (U.K.)

Antioxidant, Iron-chelating and Anti-glucosidase Activities of Typha ...

African Journals Online (AJOL)

Iron chelating activity was assessed using a ferrozine-based assay. Anti- glucosidase activity was determined using 4-nitrophenyl ... flavonoid (TF) content was determined based an aluminum chloride colorimetric assay [6]. TF content was ..... Dietary iron restriction or iron chelation protects from diabetes and loss of β-cell.

Olivine-type cathode for rechargeable batteries: Role of chelating agents

International Nuclear Information System (INIS)

Kandhasamy, Sathiyaraj; Singh, Pritam; Thurgate, Stephen; Ionescu, Mihail; Appadoo, Dominique; Minakshi, Manickam

2012-01-01

Highlights: ► Olivine powder was synthesized by sol–gel method using a range of chelating agents. ► Role of chelating agents in olivine cathode was investigated for battery application. ► Battery was fabricated with olivine cathode, Zn anode and aqueous electrolyte. ► Synergetic effect of additives (CA + TEA + PVP) led to improved storage capacity. - Abstract: Olivine (LiCo 1/3 Mn 1/3 Ni 1/3 PO 4 ) powders were synthesized at 550–600 °C for 6 h in air by a sol–gel method using multiple chelating agents and used as a cathode material for rechargeable batteries. Range of chelating agents like a weak organic acid (citric acid – CA), emulsifier (triethanolamine – TEA) and non-ionic surfactant (polyvinylpyrrolidone – PVP) in sol–gel wet chemical synthesis were used. The dependence of the physicochemical properties of the olivine powders such as particle size, morphology, structural bonding and crystallinity on the chelating agent was extensively investigated. Among the chelating agents used, unique cycling behavior (75 mAh/g after 25 cycles) is observed for the PVP assisted olivine. This is due to volumetric change in trapped organic layer for first few cycles. The trapped organic species in the electrode–electrolyte interface enhances the rate of lithium ion diffusion with better capacity retention. In contrast, CA and TEA showed a gradual capacity fade of 30 and 38 mAh/g respectively after multiple cycles. The combination of all the three mixed chelating agents showed an excellent electrochemical behavior of 100 mAh/g after multiple cycles and the synergistic effect of these agents are discussed.

Obtention of Uo3 by means of denitration of uranyl nitrate in a fluidized-bed

International Nuclear Information System (INIS)

Santos, W.R. dos; Costa, P.A.

1990-01-01

A fluidized-bed pilot unit for the production of UO 3 installed at IPEN-CNEN/SP is described. Its capacity is of 20 kg U/h in a continuous process. The main components of this pilot unit are: a system for the concentration of nuclearly pure uranyl nitrate (≅ 100 g U/L), a system for the denitration of the concentrated uranyl nitrate, an absorption system for NO 2 produced during the denitration reaction and, finally, a system for the dissolution of UO 3 that does not meet the specifications. The operational troubles found during the initial runs are presented. The results of the physical and chemical analysis of the UO 3 produced are discussed and a comparison is made for the UO 3 obtained by both fluidized-bed and wet processes. (author) [pt

An evaluation of Tiron (sodium 4,5-dihydroxybenzene-1,3-disulfonate) as a rescue agent for the nephropathy induced by uranyl fluoride (UO2F2) in rats

International Nuclear Information System (INIS)

Zalups, R.K.

1991-01-01

Tiron (sodium 4,5-dihydroxybenzene-1,3-disulfonate) was tested as a potential rescue agent for the nephropathy induced by uranyl fluoride (UO2F2) in rats. When uranyl fluoride was administered (i.v.) to male Sprague-Dawley rats at a dose that delivered 250 micrograms U/kg, moderate to severe cellular necrosis occurred in pars recta segments of proximal tubules in the cortex and outer stripe of the outer medulla of the rats' kidneys within four days after treatment. The severity of renal tubular injury was not significantly diminished when rats were given a 10, 100 or 1,000 mg/kg dose of Tiron (i.p.) 30 minutes after the administration of uranyl fluoride. No obvious protection was noted even when the rats were given a 1,000 mg/kg dose of Tiron 15, 30 and 90 minutes after the administration of uranyl fluoride. Therefore, Tiron does not appear to provide rats substantial protection against a dose of uranyl fluoride that induces moderate to severe renal injury

Tritium gettering from air with hydrogen uranyl phosphate. Revision 1

International Nuclear Information System (INIS)

Souers, P.C.; Uribe, F.S.; Stevens, C.G.; Tsugawa, R.T.

1985-01-01

Hydrogen uranyl phosphate (HUP), a solid proton electrolyte, getters tritium gas and water vapor from air by DC electrical action. We have reduced the formation of residual tritiated water to less than 2%, and demonstrated that HUP can clean a 5.5 m 3 working glove box. Data are presented to illustrate the parameters of the gettering and a model is derived. Two other tritium gettering electrolytes have been discovered. 9 refs., 5 figs., 3 tabs

Uranyl(VI)-acetylacetonate coordination compounds with various N-heterocyclic ligands

International Nuclear Information System (INIS)

Kawasaki, Takeshi; Nishimura, Tatsuru; Kitazawa, Takafumi

2010-01-01

Seven uranyl(VI) complexes, [UO 2 (acac) 2 (L)] [L=4-methylpyridine (1), 4-ethylpyridine (2), 2,4-dimethylpyridine (3), (-)-nicotine (4), and imidazole (5)], [{UO 2 (acac) 2 } 2 -(4,4'-bipyridine)] (6), and [(2,2'-bipyridine) 2 H][UO 2 (acac)(NO 3 ) 2 ] (7) have been synthesized and characterized crystallographically. The coordination geometry of U has a UNO 6 pentagonal-bipyramidal coordination in 1-6, and a UO 8 hexagonal-bipyramidal coordination in 7. (author)

Tris-amidoximate uranyl complexes via η2 binding mode coordinated in aqueous solution shown by X-ray absorption spectroscopy and density functional theory methods.

Science.gov (United States)

Zhang, Linjuan; Qie, Meiying; Su, Jing; Zhang, Shuo; Zhou, Jing; Li, Jiong; Wang, Yu; Yang, Shitong; Wang, Shuao; Li, Jingye; Wu, Guozhong; Wang, Jian Qiang

2018-03-01

The present study sheds some light on the long-standing debate concerning the coordination properties between uranyl ions and the amidoxime ligand, which is a key ingredient for achieving efficient extraction of uranium. Using X-ray absorption fine structure combined with theoretical simulation methods, the binding mode and bonding nature of a uranyl-amidoxime complex in aqueous solution were determined for the first time. The results show that in a highly concentrated amidoxime solution the preferred binding mode between UO 2 2+ and the amidoxime ligand is η 2 coordination with tris-amidoximate species. In such a uranyl-amidoximate complex with η 2 binding motif, strong covalent interaction and orbital hybridization between U 5f/6d and (N, O) 2p should be responsible for the excellent binding ability of the amidoximate ligand to uranyl. The study was performed directly in aqueous solution to avoid the possible binding mode differences caused by crystallization of a single-crystal sample. This work also is an example of the simultaneous study of local structure and electronic structure in solution systems using combined diagnostic tools.

Metal-chelating active packaging film enhances lysozyme inhibition of Listeria monocytogenes.

Science.gov (United States)

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

2014-07-01

Several studies have demonstrated that metal chelators enhance the antimicrobial activity of lysozyme. This study examined the effect of metal-chelating active packaging film on the antimicrobial activity of lysozyme against Listeria monocytogenes. Polypropylene films were surface modified by photoinitiated graft polymerization of acrylic acid (PP-g-PAA) from the food contact surface of the films to impart chelating activity based on electrostatic interactions. PP-g-PAA exhibited a carboxylic acid density of 113 ± 5.4 nmol cm(-2) and an iron chelating activity of 53.7 ± 9.8 nmol cm(-2). The antimicrobial interaction of lysozyme and PP-g-PAA depended on growth media composition. PP-g-PAA hindered lysozyme activity at low ionic strength (2.48-log increase at 64.4 mM total ionic strength) and enhanced lysozyme activity at moderate ionic strength (5.22-log reduction at 120 mM total ionic strength). These data support the hypothesis that at neutral pH, synergy between carboxylate metal-chelating films (pKa(bulk) 6.45) and lysozyme (pI 11.35) is optimal in solutions of moderate to high ionic strength to minimize undesirable charge interactions, such as lysozyme absorption onto film. These findings suggest that active packaging, which chelates metal ions based on ligand-specific interactions, in contrast to electrostatic interactions, may improve antimicrobial synergy. This work demonstrates the potential application of metal-chelating active packaging films to enhance the antimicrobial activity of membrane-disrupting antimicrobials, such as lysozyme.

Determination of uranyl nitrate diffusion coefficients in organic and aqueous media using the porous diaphragm method

International Nuclear Information System (INIS)

Chierice, G.O.

1974-01-01

The diffusion coefficient is one of the parameters necessary for the obtention of the extraction exponential coefficients, that are contained within the H.T.U. (height of transfer unity) calculation expression, when operating with continuous organic phase. The organic phase used was tri-n-butyl-phosphate (TBP) and varsol in the 35% and 65% proportions respectively. After each experiment, the uranium content present in each compartment was spectrophotometrically determined and the quantities contained in the aqueous phases were determined by means of volumetric titration. It was found out that the uranyl ion diffusion coefficient is two and one half times less in organic phase, this just being attributed to the greater interactions of the uranyl ions in organic than in aqueous medium

The influence of functional groups on the permeation and distribution of antimycobacterial rhodamine chelators.

Science.gov (United States)

Moniz, T; Leite, A; Silva, T; Gameiro, P; Gomes, M S; de Castro, B; Rangel, M

2017-10-01

We formerly hypothesized a mechanism whereby the antimycobacterial efficiency of a set of rhodamine labelled iron chelators is improved via the rhodamine fluorophore which enhances the chelators' permeation properties through membranes. To validate our hypothesis in a cellular context and to understand the influence of the structure of the fluorophore on the chelator's uptake and distribution within macrophages we now report comparative confocal microscopy studies performed with a set of rhodamine labelled chelators. We identify the functional groups of the chelator's framework that favor uptake by macrophages and conclude that the antimycobacterial effect is strongly related with the capacity of the chelator to distribute within the host cell and its compartments, a property that is closely related with the chelators' ability to interact with membranes. The quantification of the chelators' interaction with membranes was assessed through measurement of the corresponding partition constants in liposomes. The overall results support that the compounds which are preferentially taken up are the most efficient antimycobacterial chelators and for that reason we infer that the biological activity is modulated by the structural features of the fluorophore. Copyright © 2017 Elsevier Inc. All rights reserved.

Theoretical analysis of the influence of chelate-ring size and vicinal effects on electronic circular dichroism spectra of cobalt(III) EDDA-type complexes.

Science.gov (United States)

Wang, Ai; Wang, Yuekui; Jia, Jie; Feng, Lixia; Zhang, Chunxia; Liu, Linlin

2013-06-20

To assess the contributions of configurational and vicinal effects as well as chelate-ring size to rotational strengths, the geometries of a series of cobalt(III) complexes [Co(EDDA-type)(L)](±) with the tetradentate EDDA-type ligands, EDDA (ethylenediamine-N,N'-diacetate), DMEDDA (N,N'-dimethylethylenediamine-N,N'-diacetate), DEEDDA (N,N'-diethylethylenediamine-N,N'-diacetate), and a bidentate ancillary ligand L (L = ethylenediamine, oxalate, carbonate, (S)-alanine, and malonate) in aqueous solution have been optimized at the DFT/B3LYP/6-311++G(2d,p) level of theory. Based on the optimized geometries, the excitation energies and oscillator and rotational strengths have been calculated using the time-dependent density functional theory (TDDFT) method with the same functional and basis set. The calculated circular dichroism (CD) curves are in excellent agreement with the observed ones except for some small red or blue shifts in peak wavelengths. For the influence of chelate-ring size of the bidentate ligands on the CD intensities, a qualitative analysis together with the quantitative TDDFT calculation reveal that it depends on the symmetry of the cobalt-EDDA backbone. For the s-cis-isomers, the influence is negligible due to the perturbation is symmetric. For the uns-cis-isomers, the perturbation is unsymmetric. Since a small ring size means a large perturbation, this leads to the integral CD intensities decreasing with increasing the chelate ring size. The vicinal effects of asymmetric nitrogens incorporate both the substitutent effects and conformational relaxation effects, with the former being dominant. By analyzing the contributions of chiral arrays to rotational strengths, we found that the part of contributions dominated by the S-type chiral nitrogens could be considered as a good measure for the vicinal effects of chiral nitrogens. In addition, we found that the twist form (δ/λ) of the backbone ethylenediamine ring (E-ring) of the coordinated EDDA

Iron chelators ICL670 and 311 inhibit HIV-1 transcription

International Nuclear Information System (INIS)

Debebe, Zufan; Ammosova, Tatyana; Jerebtsova, Marina; Kurantsin-Mills, Joseph; Niu, Xiaomei; Charles, Sharroya; Richardson, Des R.; Ray, Patricio E.; Gordeuk, Victor R.; Nekhai, Sergei

2007-01-01

HIV-1 replication is induced by an excess of iron and iron chelation by desferrioxamine (DFO) inhibits viral replication by reducing proliferation of infected cells. Treatment of cells with DFO and 2-hydroxy-1-naphthylaldehyde isonicotinoyl hydrazone (311) inhibit expression of proteins that regulate cell-cycle progression, including cycle-dependent kinase 2 (CDK2). Our recent studies showed that CDK2 participates in HIV-1 transcription and viral replication suggesting that inhibition of CDK2 by iron chelators might also affect HIV-1 transcription. Here we evaluated the effect of a clinically approved orally effective iron chelator, 4-[3,5-bis-(hydroxyphenyl)-1,2,4-triazol-1-yl]-benzoic acid (ICL670) and 311 on HIV-1 transcription. Both ICL670 and 311 inhibited Tat-induced HIV-1 transcription in CEM-T cells, 293T and HeLa cells. Neither ICL670 nor 311 induced cytotoxicity at concentrations that inhibited HIV-1 transcription. The chelators decreased cellular activity of CDK2 and reduced HIV-1 Tat phosphorylation by CDK2. Neither ICL670A or 311 decreased CDK9 protein level but significantly reduced association of CDK9 with cyclin T1 and reduced phosphorylation of Ser-2 residues of RNA polymerase II C-terminal domain. In conclusion, our findings add to the evidence that iron chelators can inhibit HIV-1 transcription by deregulating CDK2 and CDK9. Further consideration should be given to the development of iron chelators for future anti-retroviral therapeutics

Interaction of chelating agents with cadmium in mice and rats

International Nuclear Information System (INIS)

Eybl, V.; Sykora, J.; Koutensky, J.; Caisova, D.; Schwartz, A.; Mertl, F.

1984-01-01

The influence of several chelating agents (CaDTPA, ZnDTPA, CaEDTA, ZnEDTA, DMSA, D-penicillamine and DMPS, DMP and DDC) on the acute toxicity of CdCl 2 and on the whole body retention and tissue distribution of cadmium after the IV application of /sup 115mCdCl 2 was compared in mice. The chelating agents were applied immediately after the application of cadmium. CaDTPA, ZnDTPA and DMSA appeared to be the most effective antidotes. However, DMSA increased the amount of cadmium retained in kidneys. The treatement of cadmium-poisoned mice with the combination of DMSA (IP) and ZnDTPA (SC) (all the compounds were injected in equimolar dose) decreased the toxicity of cadmium more than treatment with one chelating agents (given in a 2:1 dose). However, by studying the effect of these chelating agents and their combination application of the antidotes showed little or no improvement over the results obtained with the most effective of the individual components. In the urine of rats injected with CdCl 2 and treated with the chelating agents (CaDTPA, ZnDTPA, DMSA), the presence of cadmium complexes was demonstrated. The formation of mixed ligand chelates in vivo was not proved. Experiments in mice given a single injection of /sup 115m/Cd-labeled Cd complexes of DMPS, DMSA and DTPA showed a high retention of cadmium in the organisms after the IV application of CdDMPS and CdDMSA complexes

Bone marrow and chelatable iron in patients with protein energy ...

African Journals Online (AJOL)

chelatable iron is present and is excreted in the urine of children with kwashiorkor ... venous blood sample was drawn for routine biochemical and haematological .... storage.l.1:m In response to chelation, the kwashiorkor children excrete large ...

In vitro and in vivo evaluation of potential aluminum chelators.

Science.gov (United States)

Graff, L; Muller, G; Burnel, D

1995-10-01

The potential for aluminium (Al) chelation by different compounds was determined using 2 in vitro techniques. The formation of stable complexes with Al in an aqueous solution was evaluated using pulse polarography. This technique allowed the influence of temperature and calcium (Ca) to be studied for each compound. Certain compounds (EDDHA, HAES, citric acid and HBED) showed great chelation in the absence of Ca2+ at a temperature of 37 +/- 1 C. An ultrafiltration technique combined with Al determination by atomic emission spectroscopy allowed the efficiency of different substances to complex Al that were previously bound to serum proteins to be estimated. The kinetics of chelation and minimum efficient concentration have been determined for all products studied. EDDHA had chelation potential similar to DFO. The real efficacies of the compounds were studied in vivo to compare the effectiveness of repeated administrations of the best chelating agents (EDDHA, DFO, HAES and tartaric acid) on the distribution and excretion of Al after repeated i.p. administrations to rats. Intraperitoneal EDDHA significantly increased urinary metal (Al, Ca, Cu, Fe and Zn) excretion. These excretions may be correlated to a renal toxic potential property.

Contribution to the study of the mechanism of extraction of uranyl chloride by long chain aliphatic amines; Contribution a l'etude du mecanisme d'extraction du chlorure d'uranyle par les amines aliphatiques a longues chaines

Energy Technology Data Exchange (ETDEWEB)

Rubinstein, G R [Commissariat a l' Energie Atomique, Saclay (France). Centre d' Etudes Nucleaires

1965-06-01

After having studied and developed the mechanisms which may 'a priori' explain the extraction process (co-ordination, ion association or intermediate mechanism), experience shows that ion association only should be taken into consideration. The structure of the organic complex of uranyl chloride has been defined on the basis of the study of the variation of the distribution coefficient of uranium between the two phases at the equilibrium as a function of successively the activity of Cl{sup -} ions in the aqueous phase, the concentration of amine salt in the organic phase and finally of the concentration of uranium in the aqueous phase. The plotting of the results in bi-logarithmic co-ordinates enables us to propose the following formula for the extracted compound: UO{sub 2}Cl{sub 4}{sup --}(NR{sub 3}H{sup +}){sub 2}. The calculation of the equilibrium constant of formation of the organic compound of uranyl chloride has been possible in the case of diluted solutions of uranium only. (author) [French] Apres avoir expose et developpe les mecanismes qui a priori pouvaient expliquer le processus d'extraction (coordination, association d'ions ou mecanisme intermediaire), le recours a l'experience a finalement permis de ne retenir que l'association d'ions. La structure du complexe organique de chlorure d'uranyle a ete definie a partir de l'etude de la variation du coefficient de partage de l'uranium entre les deux phases a l'equilibre en fonction successivement de l'activite des ions Cl{sup -} en phase aqueuse, de la concentration de sel d'amine en phase organique et enfin de la concentration d'uranium de la phase aqueuse. La representation bilogarithmique des resultats de ces essais a permis de proposer la formule suivante pour le compose extrait: UO{sub 2}Cl{sub 4}{sup --}(NR{sub 3}H{sup +}){sub 2}. Le calcul de la constante d'equilibre de formation du compose organique de chlorure d'uranyle a ete seulement possible pour les solutions diluees en uranium. (auteur)

Determination of halogens, silicon, phosphorus, carbon, sulfur, tributyl phosphate and of free acid in uranyl nitrate solutions

International Nuclear Information System (INIS)

Chu Van Vinh

2003-01-01

High-purity uranium compounds are widely used in nuclear field in the form of uranyl nitrate or uranium oxides. In production of uranium material the estimation and the control of products quality is necessary and very important. Halogens was separated from uranium compounds by steam distillation and they were later determined by high performance liquid chromatography (HPLC) for Cl - , Br - , I - ions. Br - was also determined by spectrophotometric and iodide by the individual pulse polarography. Silicon and phosphorus in uranyl nitrate solutions were determined by the photometric method. Sulfur was determined as sulfate form by the measurement of turbidity by the titrimetry. TBP in kerosene and free acid in aqueous solution were determined by the titration. (author)

Selectivity in extraction of copper and indium with chelate extractants

International Nuclear Information System (INIS)

Zivkovic, D.

2003-01-01

Simultaneous extraction of copper and indium with chelate extractants (LIX84 and D2E11PA) was described. Stechiometry of metal-organic complexes examined using the method of equimolar ratios resulted in CuR 2 and InR 3 forms of hydrophobic extracting species. A linear correlation was obtained between logarithm of distribution coefficients and chelate agents and pH, respectively. Selectivity is generally higher with higher concentrations of chelate agents in the organic phase, and is decreased with increase of concentration of hydrogen ions in feeding phase. (Original)

Complex formation between uranyl and various thiosemicarbazide derivatives

International Nuclear Information System (INIS)

Chuguryan, D.G.; Dzyubenko, V.I.

1987-01-01

Complex formation between hexavalent uranium and salicylaldehyde thiosemicarbazone (H 2 L), salicylaldehyde S-methyl-isothiosemicarbazone (H 2 Q), S-methyl-N 1 ,N 4 -bis(salicylidene)isothiosemicarbazide(H 2 Z), and thiosemicarbazidodiacetic acid (H 2 R) has been studied spectrophotometrically in solution. Stability constants for complexes having the composition UO 2 A have been calculated. Solid uranyl derivatives having the composition UO 2 L x 2H 2 O, UO 2 Q x 2H 2 O, UO 2 Z x 2H 2 O, and UO 2 R x 2H 2 O have been obtained. These derivatives were isolated and their IR spectroscopic behavior and thermal properties were investigated

Glutathione attenuates uranyl toxicity in Lactococcus lactis

International Nuclear Information System (INIS)

Fahmy, Karim; Oertel, Jana; Solioz, M.

2017-01-01

We investigated the role of intracellular glutathione (GSH), which in a large number of taxa plays a role in the protection against the toxicity of heavy metals. Anaerobically grown Lactococcus lactis containing an inducible GSH synthesis pathway was used as a model organism allowing the study of GSH-dependent uranyl detoxification without interference from additional reactive oxygen species. Microcalorimetric measurements of the metabolic heat showed that intracellular GSH attenuates the toxicity of uranium at a concentration in the range of 10-150 μM. Isothermal titration calorimetry revealed the endothermic binding of U(VI) to the carboxyl group(s) of GSH. The data indicate that the primary detoxifying mechanism is the intracellular sequestration of carboxyl-coordinated U(VI) into an insoluble complex with GSH.

Glutathione attenuates uranyl toxicity in Lactococcus lactis

Energy Technology Data Exchange (ETDEWEB)

Fahmy, Karim; Oertel, Jana [Helmholtz-Zentrum Dresden-Rossendorf e.V., Dresden (Germany). Biophysics; Obeid, M. [Technische Univ. Dresden (Germany); Solioz, M. [Bern Univ. (Switzerland)

2017-06-01

We investigated the role of intracellular glutathione (GSH), which in a large number of taxa plays a role in the protection against the toxicity of heavy metals. Anaerobically grown Lactococcus lactis containing an inducible GSH synthesis pathway was used as a model organism allowing the study of GSH-dependent uranyl detoxification without interference from additional reactive oxygen species. Microcalorimetric measurements of the metabolic heat showed that intracellular GSH attenuates the toxicity of uranium at a concentration in the range of 10-150 μM. Isothermal titration calorimetry revealed the endothermic binding of U(VI) to the carboxyl group(s) of GSH. The data indicate that the primary detoxifying mechanism is the intracellular sequestration of carboxyl-coordinated U(VI) into an insoluble complex with GSH.

ELECTED PROBLEMS RELATED TO ENVIRONMENTAL HEAVY METALS EXPOSURE AND CHELATION THERAPY

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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.

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.

EDTA chelation therapy for cardiovascular disease: a systematic review

Directory of Open Access Journals (Sweden)

Wu Ping

2005-11-01

Full Text Available Abstract Background Numerous practitioners of both conventional and complementary and alternative medicine throughout North America and Europe claim that chelation therapy with EDTA is an effective means to both control and treat cardiovascular disease. These claims are controversial, and several randomized controlled trials have been completed dealing with this topic. To address this issue we conducted a systematic review to evaluate the best available evidence for the use of EDTA chelation therapy in the treatment of cardiovascular disease. Methods We conducted a systematic review of 7 databases from inception to May 2005. Hand searches were conducted in review articles and in any of the trials found. Experts in the field were contacted and registries of clinical trials were searched for unpublished data. To be included in the final systematic review, the studies had to be randomized controlled clinical trials. Results A total of seven articles were found assessing EDTA chelation for the treatment of cardiovascular disease. Two of these articles were subgroup analyses of one RCT that looked at different clinical outcomes. Of the remaining five studies, two smaller studies found a beneficial effect whereas the other three exhibited no benefit for cardiovascular disease from the use of EDTA chelation therapy. Adverse effects were rare but those of note included a few cases of hypocalcemia and a single case of increased creatinine in a patient on the EDTA intervention. Conclusion The best available evidence does not support the therapeutic use of EDTA chelation therapy in the treatment of cardiovascular disease. Although not considered to be a highly invasive or harmful therapy, it is possible that the use of EDTA chelation therapy in lieu of proven therapy may result in causing indirect harm to the patient.

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…

Copper chelators: chemical properties and bio-medical applications.

Science.gov (United States)

Tegoni, M; Valensin, D; Toso, L; Remelli, M

2014-01-01

Copper is present in different concentrations and chemical forms throughout the earth crust, surface and deep water and even, in trace amounts, in the atmosphere itself. Copper is one of the first metals used by humans, the first artifacts dating back 10,000 years ago. Currently, the world production of refined copper exceeds 16,000 tons/year. Copper is a micro-element essential to life, principally for its red-ox properties that make it a necessary cofactor for many enzymes, like cytochrome-c oxidase and superoxide dismutase. In some animal species (e.g. octopus, snails, spiders, oysters) copper-hemocyanins also act as carriers of oxygen instead of hemoglobin. However, these red-ox properties also make the pair Cu(+)/Cu(2+) a formidable catalyst for the formation of reactive oxygen species, when copper is present in excess in the body or in tissues. The treatment of choice in cases of copper overloading or intoxication is the chelation therapy. Different molecules are already in clinical use as chelators or under study or clinical trial. It is worth noting that chelation therapy has also been suggested to treat some neurodegenerative diseases or cardiovascular disorders. In this review, after a brief description of the homeostasis and some cases of dyshomeostasis of copper, the main (used or potential) chelators are described; their properties in solution, even in relation to the presence of metal or ligand competitors, under physiological conditions, are discussed. The legislation of the most important Western countries, regarding both the use of chelating agents and the limits of copper in foods, drugs and cosmetics, is also outlined.

Direct 99mTc labeling of monoclonal antibodies: radiolabeling and in vitro stability

International Nuclear Information System (INIS)

Garron, J.Y.; Moinereau, M.; Pasqualini, R.; Saccavini, J.C.

1991-01-01

Direct labeling involves 99m Tc 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 99m Tc. The direct 99m Tc 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 99m Tc requires the generation of sulfhydryl groups, which show high affinity binding sites for 99m Tc. 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 99m Tc-antibody bond with three ligands, Chelex 100 (a metal chelate-type resin), free DTPA solution and 1% HSA solution. Very good 99m Tc-antibody stability is obtained with activated IgG (IgGa) and Fab' fragment, which makes these substances possible candidates for immunoscintigraphy use. (author)

Preparations and crystal structures of 8 coordinate uranyl(VI) complexes having macrocyclic ligands derived from pyrroledicarboxialdehydes and diamines

International Nuclear Information System (INIS)

Komagine, J.; Takeda, M.; Takahashi, M.

2006-01-01

Six 8-coordinate uranyl(VI) complexes with macrocyclic Schiff base ligands derived from 2,6-pyrroledicarboxialdehyde and diamines are prepared and the crystal structures for two of them are determined focusing on the relation between the size of the ligands and U-N bond distances. No difference in average uranyl bond distances and bond angles are observed between [UO 2 (bipytn)](a) and [UO 2 (bipydmtn)](b). U-N bonds of these complexes are, however, not equal; the U-N(pyrrole) bonds [2.45(a), 2.44(b) A] are much shorter than the U-N(imine) bonds [2.67(a), 2.67(b) A]. (author)

A review of pitfalls and progress in chelation treatment of metal poisonings.

Science.gov (United States)

Andersen, Ole; Aaseth, Jan

2016-12-01

Most acute and chronic human metal poisonings are due to oral or inhalation exposure. Almost 80% of published animal experiments on chelation in metal poisoning used single or repeated intraperitoneal, intramuscular or intravenous administration of metal and chelator, impeding extrapolation to clinical settings. Intramuscular administration of dimercaptopropanol (BAL) has until now been used in acute arsenic, lead, and mercury poisonings, but repeated BAL administration increased the brain uptake of As, Pb and Hg in experimental animals. Also, diethyl dithiocarbamate (DDC) has been used as antidote in acute experimental animal parenteral Cd poisoning, and both DDC and tetraethylthiuram disulfide (TTD, disulfiram, Antabuse) have been used in nickel allergic patients. However, even one dose of DDC given immediately after oral Cd or Ni increased their brain uptake considerably. The calcium salt of ethylenediamminetetraacetic acid (CaEDTA) but not dimercaptosuccinic acid (DMSA) increased the brain uptake of Pb. In oral Cd or Hg poisoning, early oral administration of DMSA or dimercaptopropane sulfonate (DMPS) increased survival and reduced intestinal metal uptake. Oral administration of Prussian Blue or resins with fixed chelating groups that are not absorbed offer chelation approaches for decorporation after oral exposure to various metals. Diethylenetriaminepentaacetic acid (DTPA) nebulizers for pulmonary chelation after inhalation exposure need further development. Also, combined chelation with more than one compound may offer extensive advances. Solid knowledge on the chemistry of metal chelates together with relevant animal experiments should guide development of chelation procedures to alleviate and not aggravate the clinical status of poisoned patients. Copyright © 2016 Elsevier GmbH. All rights reserved.

New insight into the ternary complexes of uranyl carbonate in seawater.

Science.gov (United States)

Beccia, M R; Matara-Aho, M; Reeves, B; Roques, J; Solari, P L; Monfort, M; Moulin, C; Den Auwer, C

2017-11-01

Uranium is naturally present in seawater at trace levels and may in some cases be present at higher concentrations, due to anthropogenic nuclear activities. Understanding uranium speciation in seawater is thus essential for predicting and controlling its behavior in this specific environmental compartment and consequently, its possible impact on living organisms. The carbonato calcic complex Ca 2 UO 2 (CO 3 ) 3 was previously identified as the main uranium species in natural seawater, together with CaUO 2 (CO 3 ) 3 2- . In this work, we further investigate the role of the alkaline earth cation in the structure of the ternary uranyl-carbonate complexes. For this purpose, artificial seawater, free of Mg 2+ and Ca 2+ , using Sr 2+ as a spectroscopic probe was prepared. Combining TRLIF and EXAFS spectroscopy, together with DFT and theoretical thermodynamic calculations, evidence for the presence of Sr alkaline earth counter ion in the complex structure can be asserted. Furthermore, data suggest that when Ca 2+ is replaced by Sr 2+ , SrUO 2 (CO 3 ) 3 2- is the main complex in solution and it occurs with the presence of at least one monodentate carbonate in the uranyl coordination sphere. Copyright © 2017 Elsevier Ltd. All rights reserved.

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

Science.gov (United States)

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

2016-05-01

A chemically modified electrode (CME) on a gold surface assembled with a ω-phosphonic acid terminated thiol was investigated for its capability to complex uranyl ions. The electrode, characterized by electrochemical techniques, demonstrated to be effective for the determination of uranyl at sub-μgL(-1) level by differential pulse adsorptive stripping voltammetry (DPAdSV) in environmental waters, also in presence of humic matter and other potential chelating agents. The accuracy of the measurements was investigated employing as model probes ligands of different complexing capability (humic acids and EDTA). Copyright © 2016 Elsevier B.V. All rights reserved.

Charge-density matching in organic-inorganic uranyl compounds

Energy Technology Data Exchange (ETDEWEB)

Krivovichev, S.V. [Saint Petersburg State Univ., Dept. of Crystallography, Faculty of Geology (Russian Federation); Krivovichev, S.V.; Tananaev, I.G.; Myasoedov, B.F. [Russian Academy of Sciences, A.N. Frumkin Institute of Physical Chemistry and Electrochemistry, Moscow (Russian Federation)

2007-10-15

Single crystals of [C{sub 10}H{sub 26}N{sub 2}][(UO{sub 2})(SeO{sub 4}){sub 2}(H{sub 2}O)](H{sub 2}SeO{sub 4}){sub 0.85}(H{sub 2}O){sub 2} (1), [C{sub 10}H{sub 26}N{sub 2}][(UO{sub 2})(SeO{sub 4}){sub 2}] (H{sub 2}SeO{sub 4}){sub 0.50}(H{sub 2}O) (2), and [C{sub 8}H{sub 20}N]{sub 2}[(UO{sub 2})(SeO{sub 4}){sub 2}(H{sub 2}O)] (H{sub 2}O) (3) were prepared by evaporation from aqueous solution of uranyl nitrate, selenic acid and the respective amines. The structures of the compounds have been solved by direct methods and structural models have been obtained. The structures of the compounds 1, 2, and 3 contain U and Se atoms in pentagonal bipyramidal and tetrahedral coordinations, respectively. The UO{sub 7} and SeO{sub 4} polyhedra polymerize by sharing common O atoms to form chains (compound 1) or sheets (compounds 2 and 3). In the structure of 1, the layers consisting of hydrogen-bonded [UO{sub 2}(SeO{sub 4}){sub 2}(H{sub 2}O)]{sup 2-} chains are separated by mixed organic-inorganic layers comprising from [NH{sub 3}(CH{sub 2}){sub 10}NH{sub 3}]{sup 2+} molecules, H{sub 2}O molecules, and disordered electroneutral (H{sub 2}SeO{sub 4}) groups. The structure of 2 has a similar architecture but a purely inorganic layer is represented by a fully connected [UO{sub 2}(SeO{sub 4}){sub 2}]{sup 2-} sheet. The structure of 3 does not contain disordered (H{sub 2}SeO{sub 4}) groups but is based upon alternating [UO{sub 2}(SeO{sub 4}){sub 2}(H{sub 2}O)]{sup 2-} sheets and 1.5-nm-thick organic blocks consisting of positively charged protonated octylamine molecules, [NH{sub 3}(CH{sub 2}){sub 7}CH{sub 3}]{sup +}. The structures may be considered as composed of anionic inorganic sheets (2D blocks) and cationic organic blocks self-organized according to competing hydrophilic-hydrophobic interactions. Analysis of the structures allows us to conclude that the charge-density matching principle is observed in uranyl compounds. In order to satisfy some basic peculiarities of uranyl (in

Sorption of uranyl species on zircon and zirconia

International Nuclear Information System (INIS)

Lomenech, C.; Drot, R.; Simoni, E.; Ehrhardt, J.J.; Mielczarski, J.

2002-01-01

The safety of a long-term storage of radioactive waste in deep geological repositories would be strongly affected by the migration properties of radionuclides through the different barriers to the surface of the earth. Since the main process involved in the retention of radioactive ions is their sorption at the water/ mineral interface, a quantitative description of the sorption reactions is needed. Macroscopic data have for a long time been the only source of information used to propose a modelling of sorption equilibria, although they bring no direct information on the nature of the sorbed species; a microscopic structural investigation of the surface complexes is difficult indeed, because of the small amount of matter sorbed. Thus, in this study, parallel to the macroscopic measurements, different complementary spectroscopic techniques have been used in order to determine the nature of the surface species. As the final purpose of such a study is the simulation of the experimental retention data, the precise structural identification of the sorption equilibria will then be very useful to constrain the data simulation code. In this work, we present the results of both macroscopic and microscopic studies of the sorption of uranyl species on zircon and zirconia. The first part of our macroscopic approach was the surface characterisation of the non-sorbed materials by the determination of the specific areas, of the pH of the isoelectric points, and of the sorption site numbers, while the second part aimed at obtaining the sorption isotherms (percentage of sorption versus pH), which was performed using alpha spectrometry, for different uranyl concentrations, media (NaClO 4 or KNO 3 ) and ionic strengths. The spectroscopic identification of the different surface complexes and sorption sites has been carried out using four different spectroscopies. Whereas tune-resolved laser spectro-fluorimetry gave a direct answer concerning the number of surface species (only for a

Structural variability in uranyl-lanthanide hetero-metallic complexes with DOTA and oxalato ligands

International Nuclear Information System (INIS)

Thuery, P.

2009-01-01

Four novel 4f-5f hetero-metallic complexes could be obtained from the reaction of uranyl and lanthanide nitrates with DOTA (H 4 L) under hydrothermal conditions. In all cases, as in the previous examples reported, additional oxalato ligands are formed in situ. Variations in the stoichiometry of the final products and the presence of hydroxo ions in some cases appear to result in a large structural variability. In the two isomorphous complexes [(UO 2 ) 2 Ln 2 (L) 2 (C 2 O 4 )] with Ln = Sm(1) or Eu(2), the lanthanide ion is located in the N 4 O 4 site and is also bound to a carboxylate oxygen atom from a neighbouring unit, to give zigzag chains which are further linked to one another by [(UO 2 ) 2 (C 2 O 4 )] 2+ di-cations, resulting in the formation of a 3D framework. In [(UO 2 ) 4 Gd 2 (L) 2 (C 2 O 4 ) 3 (H 2 O) 6 ].2H 2 O (3), 2D bilayer subunits of the 'double floor' type with uranyl oxalate pillars are assembled into a 3D framework by other, disordered uranyl ions. [(UO 2 ) 2 Gd(L)(C 2 O 4 )(OH)].H 2 O (4) is a 2D assembly in which cationic {[(UO 2 ) 2 (C 2 O 4 )(OH)] + } n chains are linked to one another by the [Gd(L)] - groups. The most notable feature of this compound is the environment of the 4f ion, which is eight-coordinate and twisted square anti-prismatic (TSA'), instead of nine-coordinate mono-capped square anti-prismatic (SA), as generally observed in DOTA complexes of gadolinium(III) and similarly-sized ions. (author)

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

Czech Academy of Sciences Publication Activity Database

Asadi, Z.; Asadi, M.; Zeinali, A.; Ranjkeshshorkaei, M.; Fejfarová, Karla; Eigner, Václav; Dušek, Michal; Dehnokhalaji, A.

2014-01-01

Roč. 126, č. 6 (2014), s. 1673-1683 ISSN 0974-3626 R&D Projects: GA ČR(CZ) GAP204/11/0809 Institutional support: RVO:68378271 Keywords : uranyl schiff base complexes * kinetic study * kinetics of thermal decomposition * X-ray crystallography * cyclic voltammetry Subject RIV: CA - Inorganic Chemistry Impact factor: 1.191, year: 2014

Interaction of chelating agents with cadmium in mice and rats.

Science.gov (United States)

Eybl, V; Sýkora, J; Koutenský, J; Caisová, D; Schwartz, A; Mertl, F

1984-01-01

The influence of several chelating agents (CaDTPA, ZnDTPA, CaEDTA, ZnEDTA, DMSA, D-penicillamine and DMPS, DMP and DDC) on the acute toxicity of CdCl2 and on the whole body retention and tissue distribution of cadmium after the IV application of 115mCdCl2 was compared in mice. The chelating agents were applied immediately after the application of cadmium. CaDTPA, ZnDTPA and DMSA appeared to be the most effective antidotes. However, DMSA increased the amount of cadmium retained in kidneys. The treatment of cadmium-poisoned mice with the combination of DMSA (IP) and ZnDTPA (SC) (all the compounds were injected in equimolar dose) decreased the toxicity of cadmium more than treatment with one chelating agents (given in a 2:1 dose). However, by studying the effect of these chelating agents and their combination of the retention and distribution of Cd in mice, it was demonstrated that the combined application of the antidotes showed little or no improvement over the results obtained with the most effective of the individual components. In the urine of rats injected with CdCl2 and treated with the chelating agents (CaDTPA, ZnDTPA, DMSA), the presence of cadmium complexes was demonstrated. The formation of mixed ligand chelates in vivo was not proved. Experiments in mice given a single injection of 115mCd-labeled Cd complexes of DMPS, DMSA and DTPA showed a high retention of cadmium in the organisms after the IV application of CdDMPS and CdDMSA complexes. PMID:6734561

Molecular dynamics simulation of local structure and vibrational spectrum of uranyl (UO2)2+ in vitreous B2O3

International Nuclear Information System (INIS)

Zhuang, Z.-H.; Liu, G. K.; Beitz, J. V.

2000-01-01

Laser spectroscopic and extended X-ray absorption fine structure (EXAFS) spectra have shown that uranium in B 2 O 3 glass matrix forms uranyl in the electronic configuration of (UO 2 ) 2+ ,but its surrounding structure is not well known. Understanding of uranyl local structure, ion-ligand interaction, and chemical stability on the nanometer scale in glasses is essential in management of long-term performance of high-level nuclear wastes after disposal in a geologic repository. In the present work, the structure, phonon density of states, and vibrational spectrum of vitreous B 2 O 3 and the surrounding environment that contains a uranyl ion have been studied using a molecular dynamics (MD) simulation method that utilizes the Born-Mayer-Huggins and Coulomb pair potentials and the Stillinger-Weber three-body potential. A system of 406 ions was considered in our calculation. Simulation of a thermal quenching from 3000 K to 300 K was performed to generate a uniform and equilibrium model glass matrix before structure configuration and vibrational frequencies were obtained from the system. The structure of the simulated glass is in agreement with that reported by Krogh-Moe and Mozzi et al. The characteristic network of planar boroxol (B 3 O 6 ) rings is evident in the simulated system. A configuration of a U 6+ cation in the vitreous B 2 O 3 matrix is shown in Fig. 1. It is shown that a nearly linear (UO 2 ) 2+ uranyl ion is coordinated by four equatorial oxygen anions in an approximately planar arrangement. The U-O bond length is approximately 0.178 nm for the axial oxygen and 0.254 nm for the equatorial oxygen, which is in good agreement with the U-O distances obtained from fitting EXAFS spectra. Based on the simulated model structure, the uranyl vibrational spectrum is simulated and compared with experimental results obtained using site-selective fluorescence line narrowing (FLN) techniques

Controlled deprotection and reorganization of uranyl oxo groups in a binuclear macrocyclic environment

Energy Technology Data Exchange (ETDEWEB)

Jones, Guy M.; Arnold, Polly L.; Love, Jason B. [Edinburgh Univ. (United Kingdom). EaStCHEM School of Chemistry

2012-12-07

The silylated uranium(V) dioxo complex [(Me{sub 3}SiOUO){sub 2}(L){sub 2}] is inert to oxidation, but after two-electron reduction to [(Me{sub 3}SiOUO){sub 2}(L)]{sup 2-}, it can be desilylated to form [OU(μ-O){sub 2}UO(L){sub 2}]{sup 2-} with reinstated uranyl character. Removal of the silyl group uncovers new redox and oxo rearrangement chemistry for uranium, thus reforming the uranyl motif and involving the U{sup VI/V} couple in dioxygen reduction. [German] Der silylierte Dioxouran(V)-Komplex [(Me{sub 3}SiOUO){sub 2}(L){sub 2}] (A) ist inert gegen Oxidation, kann aber nach Zweielektronenreduktion zu [(Me{sub 3}SiOUO){sub 2}(L)]{sup 2-} (1) zu [OU(μ-O){sub 2}UO(L){sub 2}]{sup 2-} (2) mit wiederhergestelltem Uranylcharakter desilyliert werden. Beim Entfernen der Silylgruppe zeigt sich eine neue Redox- und Oxoumlagerungschemie des Urans unter Rueckbildung des Uranylmotivs sowie der Beteiligung des U{sup VI/V}-Paars an einer Disauerstoffreduktion.

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

OpenAIRE

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

2016-01-01

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-shel...

Synergy and antagonism between iron chelators and antifungal drugs in Cryptococcus.

Science.gov (United States)

Lai, Yu-Wen; Campbell, Leona T; Wilkins, Marc R; Pang, Chi Nam Ignatius; Chen, Sharon; Carter, Dee A

2016-10-01

Fungal infections remain very difficult to treat, and developing new antifungal drugs is difficult and expensive. Recent approaches therefore seek to augment existing antifungals with synergistic agents that can lower the therapeutic dose, increase efficacy and prevent resistance from developing. Iron limitation can inhibit microbial growth, and iron chelators have been employed to treat fungal infections. In this study, chequerboard testing was used to explore combinations of iron chelators with antifungal agents against pathogenic Cryptococcus spp. with the aim of determining how disruption to iron homeostasis affects antifungal susceptibility. The iron chelators ethylenediaminetetraacetic acid (EDTA), deferoxamine (DFO), deferiprone (DFP), deferasirox (DSX), ciclopirox olamine and lactoferrin (LF) were paired with the antifungal agents amphotericin B (AmB), fluconazole, itraconazole, voriconazole and caspofungin. All chelators except for DFO increased the efficacy of AmB, and significant synergy was seen between AmB and LF for all Cryptococcus strains. Addition of exogenous iron rescued cells from the antifungal effect of LF alone but could not prevent inhibition by AmB + LF, indicating that synergy was not due primarily to iron chelation but to other properties of LF that were potentiated in the presence of AmB. Significant synergy was not seen consistently for other antifungal-chelator combinations, and EDTA, DSX and DFP antagonised the activity of azole drugs in strains of Cryptococcus neoformans var. grubii. This study highlights the range of interactions that can be induced by chelators and indicates that most antifungal drugs are not enhanced by iron limitation in Cryptococcus. Copyright © 2016 Elsevier B.V. and International Society of Chemotherapy. All rights reserved.

Radiolabelling of antibodies with indium: Use of diethylenetriaminepentaacetic acid (DTPA) as chelating agent

International Nuclear Information System (INIS)

Loetscher, H.

1986-01-01

/sup 111/In/sup 3+/ was used to radiolabel the F(ab')/sub 2/ fragment of a monoclonal antibody (b-12) raised against a surface antigen of a mammalian breast tumor cell line (5). The in vivo distribution of the radiolabel was analyzed in mice bearing a transplant of fixed tumor cells in the left thigh. The results demonstrate that DTPA can be efficiently coupled to a tumor specific F(ab')/sub 2/ fragment and loaded with /sup 111/In/sup 3+/ yielding a stable, highly labelled complex

Characterization of the effect of serum and chelating agents on Staphylococcus aureus biofilm formation; chelating agents augment biofilm formation through clumping factor B

Science.gov (United States)

Abraham, Nabil Mathew

investigated the molecular basis of this phenomenon. Deletion and complementation analysis and thereafter antibody based inhibition assays confirmed a functional role for the surface adhesin clumping factor B as the causative determinant associated with the increased biofilm phenotype. Finally, we investigated the regulation of clumping factor B-mediated biofilm formation and the basis for the strain dependence. Regulation was determined to occur via two novel post-translational networks- one affecting ClfB activity, mediated by Ca2+ binding to the EF-Hand domain, and the other affecting protein stability, mediated by the enzymatic activity of the metalloprotease-aureolysin. Polymorphisms within the aureolysin gene sequence, between strains, was identified as the basis for some strains forming robust biofilms within chelated media versus other than do not exhibit this phenotype.

Crystal structure of the uranyl-oxide mineral rameauite

Energy Technology Data Exchange (ETDEWEB)

Plasil, Jakub [ASCR, Prague (Czech Republic). Inst. of Physics; Skoda, Radek [Masaryk Univ., Brno (Czech Republic). Dept. of Geological Sciences; Cejka, Jiri [National Museum, Prague (Czech Republic). Dept. of Mineralogy and Petrology; Bourgoin, Vincent; Boulliard, Jean-Claude [Pierre et Marie Curie Univ., Paris (France). Association Jean Wyart, Collection des Mineraux de Jussieu

2016-12-15

Rameauite is a rare supergene uranyl-oxide hydroxy-hydrate mineral that forms during hydration-oxidation weathering of uraninite. On the basis of single-crystal X-ray diffraction data collected on a microfocus source, rameauite is monoclinic, space group Cc, with a = 13.9458(19), b = 14.3105(19), c = 13.8959(18) Aa, β = 118.477(14) , V = 2437.7(6) Aa{sup 3} and Z = 4, with D{sub calc} = 5.467 g cm{sup -3}. The structure of rameauite (R = 0.060 for 1698 unique observed reflections) contains sheets of the β-U{sub 3}O{sub 8} topology, with both UO{sub 6} and UO{sub 7} bipyramids, which is similar to the sheets found in spriggite, ianthinite and wyartite. The sheets alternate with the interlayer, which contains K{sup +}, Ca{sup 2+} and H{sub 2}O molecules. Interstitial cations are linked into infinite chains that extend along [10-1]. Adjacent sheets are linked through K-O, Ca-O and H-bonds. The structural formula of rameauite is K{sub 2} Ca(H{sub 2}{sup [3]}O){sub 1}(H{sub 2}{sup [5]}O){sub 4}[(UO{sub 2}) {sub 6}O{sub 6}(OH){sub 4}](H{sub 2}{sup [4]}O){sub 1}. The empirical formula obtained from the average of eight electron-microprobe analyses is (on the basi s of 6 U p.f.u.) K{sub 1.87}(Ca{sub 1.10}Sr{sub 0.04}){sub Σ1.14}[(UO 2){sub 6}O{sub 6}(OH){sub 4.15}].6H{sub 2}O. The Raman spectrum is dominate d by U.O and O.H vibrations. A discussion of related uranyl-oxide minerals is given.

f-Element Ion Chelation in Highly Basic Media - Final Report

International Nuclear Information System (INIS)

Paine, R.T.

2000-01-01

A large body of data has been collected over the last fifty years on the chemical behavior of f-element ions. The ions undergo rapid hydrolysis reactions in neutral or basic aqueous solutions that produce poorly understood oxide-hydroxide species; therefore, most of the fundamental f-element solution chemistry has allowed synthetic and separations chemists to rationally design advanced organic chelating ligands useful for highly selective partitioning and separation of f-element ions from complex acidic solution matrices. These ligands and new examples under development allow for the safe use and treatment of solutions containing highly radioactive species. This DOE/EMSP project was undertaken to address the following fundamental objectives: (1) study the chemical speciation of Sr and lanthanide (Ln) ions in basic aqueous media containing classical counter anions found in waste matrices; (2) prepare pyridine N-oxide phosphonates and phosphonic acids that might act as selective chelator s for Ln ions in model basic pH waste streams; (3) study the binding of the new chelators toward Ln ions and (4) examine the utility of the chelators as decontamination and dissolution agents under basic solution conditions. The project has been successful in attacking selected aspects of the very difficult problems associated with basic pH solution f-element waste chemistry. In particular, the project has (1) shed additional light on the initial stages of Ln ion sol-gel-precipitate formulation under basic solution conditions; (2) generated new families of pyridine phosphonic acid chelators; (3) characterized the function of the chelators and (4) examined their utility as oxide-hydroxide dissolution agents. These findings have contributed significantly to an improved understanding of the behavior of Ln ions in basic media containing anions found in typical waste sludges as well as to the development of sludge dissolution agents. The new chelating reagents are easily made and could be

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.

Cation-Cation Complexes of Pentavalent Uranyl: From Disproportionation Intermediates to Stable Clusters

Energy Technology Data Exchange (ETDEWEB)

Mougel, Victor; Horeglad, Pawel; Nocton, Gregory; Pecaut, Jacques; Mazzanti, Marinella [CEA, INAC, SCIB, Laboratoire de Reconnaissance Ionique et Chimie de Coordination, CEA-Grenoble, 38054 GRENOBLE, Cedex 09 (France)

2010-07-01

Three new cation cation complexes of pentavalent uranyl, stable with respect to the disproportionation reaction, have been prepared from the reaction of the precursor [(UO{sub 2}py{sub 5})-(KI{sub 2}py{sub 2})]{sub n} (1) with the Schiff base ligands salen{sup 2-}, acacen{sup 2-}, and salophen{sup 2-} (H{sub 2}salen N, N'-ethylene-bis(salicylidene-imine), H{sub 2}acacen=-N, N'-ethylenebis(acetylacetone-imine), H{sub 2}salophen=N, N'-phenylene-bis(salicylidene-imine)). The preparation of stable complexes requires a careful choice of counter ions and reaction conditions. Notably the reaction of 1 with salophen{sup 2-} in pyridine leads to immediate disproportionation, but in the presence of [18]crown-6 ([18]C-6) a stable complex forms. The solid-state structure of the four tetra-nuclear complexes ([UO{sub 2}-(acacen)]{sub 4}[{mu}{sub 8}-]{sub 2}[K([18]C-6)(py)]{sub 2}) (3) and ([UO{sub 2}(acacen)](4)[{mu}{sub 8}-]).2[K([222])(py)] (4) ([UO{sub 2}(salophen)](4)[{mu}{sub 8}-K]{sub 2}[mu(5)-KI]{sub 2}[(K([18]C-6)]).2 [K([18]C-6)-(thf){sub 2}].2I (5), and ([UO{sub 2}(salen)(4)][{mu}{sub 8}-Rb]{sub 2}[Rb([18]C-6)]{sub 2}) (9) ([222] = [222]cryptand, py =pyridine), presenting a T-shaped cation cation interaction has been determined by X-ray crystallographic studies. NMR spectroscopic and UV/Vis studies show that the tetra-nuclear structure is maintained in pyridine solution for the salen and acacen complexes. Stable mononuclear complexes of pentavalent uranyl are also obtained by reduction of the hexavalent uranyl Schiff base complexes with cobaltocene in pyridine in the absence of coordinating cations. The reactivity of the complex [U{sup V}O{sub 2}(salen)(py)][Cp*{sub 2}Co] with different alkali ions demonstrates the crucial effect of coordinating cations on the stability of cation cation complexes. The nature of the cation plays a key role in the preparation of stable cation cation complexes. Stable tetra-nuclear complexes form in the presence of K

Syntheses, structures, and IR spectroscopic characterization of new uranyl sulfate/selenate 1D-chain, 2D-sheet and 3D-framework

Energy Technology Data Exchange (ETDEWEB)

Ling Jie; Sigmon, Ginger E.; Ward, Matthew; Roback, Nancy; Burns, Peter C. [Dept. of Civil Engineering and Geological Science, Univ. of Notre Dame, IN (United States)

2010-07-01

Three uranyl sulfates, (C{sub 6}H{sub 20}N{sub 4})[(UO{sub 2}){sub 2} . (SO{sub 4}){sub 4}(H{sub 2}O){sub 2}](H{sub 2}O){sub 6} (TETAUS), (C{sub 15}H{sub 14}N{sub 3})[(UO{sub 2}) . (SO{sub 4}){sub 2}](NO{sub 3})(H{sub 2}O){sub 2} (TPUS), and K{sub 2}[(UO{sub 2})(SO{sub 4}){sub 2}(H{sub 2}O)] . H{sub 2}O (KUS), and two uranyl selenates, K(H{sub 3}O)[(UO{sub 2}){sub 2} . (SeO{sub 4}){sub 3}(H{sub 2}O)](H{sub 2}O){sub 6} (KUSe) and (H{sub 3}O){sub 2}[(UO{sub 2}){sub 2}(SeO{sub 4}){sub 3} . (H{sub 2}O)] (USe), were synthesized by slow evaporation of aqueous solutions at room temperature. TETAUS crystallizes in space group P anti 1, a = 6.7186(5) A, b = 9.2625(7) A, c = 13.1078(9) A, {alpha} = 72.337(2) , {beta} = 89.198(2) , {gamma} = 70.037(1) , V = 726.89(9) A{sup 3}, Z = 1. TPUS is triclinic, P anti 1, a = 6.9732(7) A, b = 13.569(1) A, c = 13.641(1) A, {alpha} = 111.809(2) , {beta} = 102.386(2) , {gamma} = 93.833(2) , V = 1150.0(2) A{sup 3}, Z = 2. KUS is orthorhombic, Cmca, a = 12.171(2) A, b = 16.689(3) A, c = 10.997(2) A, V = 2233.8(6) A{sup 3}, Z = 8. These uranyl sulfates are built from infinite one-dimensional uranyl sulfate chains with different topologies. KUSe is monoclinic, P2{sub 1}/n, a = 14.715(1) A, b = 10.1557(7) A, c = 15.833(1) A, {beta} = 114.415(1) , V = 2154.5(3) A{sup 3}, Z = 4. Its structure is based on a two-dimensional uranyl selenate sheet. USe crystallizes in space group P2{sub 1}/c, a = 10.6124(2) A, b = 14.7717(3) A, c = 13.7139(3) A, {beta} = 96.989(1) , V = 2133.86(8) A{sup 3}, Z = 4, with a complex three-dimensional uranyl selenate framework containing channels extending in three directions. (orig.)

Application of the NICADonnan model for proton, copper and uranyl binding to humic acid

NARCIS (Netherlands)

Saito, T.; Nagasaki, S.; Tanaka, S.; Koopal, L.K.

2004-01-01

Humic acids are natural organic materials that play an important role in the migration of heavy metal and actinide ions in aquatic and soil systems. In the present study, the binding of protons, copper ions and uranyl ions to the purified Aldrich humic acid (PAHA) is investigated and the results are

Protracted chelate therapy after incorporation of plutonium 239 in rats

International Nuclear Information System (INIS)

Gemenetzis, E.

1976-01-01

The author has tested in how far 239 Pu can be mobilized by Ca and Zn, Desfenioxamin B(DFDA) and by combined doses of Ca-DTPA and DFDA. The pre-experiment covered the 239 Pu-metabolism in untreated male and female rats and the distribution in dependence of the way of application. If treatment is started immediately by multiple chelate doses, the first two injections play the main part in the decorporation of 239 Pu. The combination Ca-DTPA30 + DFDA30 μMol x kg -1 is proved to be the best means of decorporation for the whole body. The efficiency of another therapy depends essentially on the treatment used, a daily treatment showing the best effects. If treatment is started later with multiple chelate doses, the total decorporation efficiency is of less value, especially in the skeleton. Aequimolar doses of Ca-DTPA and Zn-DTPA have the same degree of efficiency. This indicates that during protracted chelate treatment starting later, Ca-DTPA could be substituted by the less toxic Zn-DTPA after incorporation of 239 Pu. These results show that intermittant administration of the week's dose is more efficient than a single chelate administration of the whole week's dose at once. Permanent chelate infusion does not seem necessary in any case since it has the same effect as 3 to 5 injections per week and is difficult to carry out in medical practice. Thus, it seems advisable to divide up the weekly dose into 3-5 injections. In case of a wound contamination, the efficiency of immediate intensive treatment depends on the 239 Pu compound used, on the chelate used, and on its dosage. (orig.) [de

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

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