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James H Yiin, Jeri L Anderson, Robert D Daniels, Stephen J Bertke, Donald A Fleming, David J Tollerud, Chih-Yu Tseng, Pi-Hsueh Chen, Kathleen M Waters
OBJECTIVE: To examine the patterns of cause-specific mortality and relationship between internal exposure to uranium and specific causes in a pooled cohort of 29,303 workers employed at three former uranium enrichment facilities in the United States with follow-up through 2011. METHODS: Cause-specific standardized mortality ratios (SMRs) for the full cohort were calculated with the U.S. population as referent. Internal comparison of the dose-response relation between selected outcomes and estimated organ doses was evaluated using regression models...
October 18, 2016: American Journal of Industrial Medicine
Claudia Joseph, Jens Mibus, Paul Trepte, Christa Müller, Vinzenz Brendler, Dan M Park, Yongqin Jiao, Annie B Kersting, Mavrik Zavarin
As a contribution to the safety assessment of nuclear waste repositories, U(VI) diffusion through the potential buffer material MX-80 bentonite was investigated at three clay dry densities over six years. Synthetic MX-80 model pore water was used as background electrolyte. Speciation calculations showed that Ca2UO2(CO3)3(aq) was the main U(VI) species. The in- and out-diffusion of U(VI) was investigated separately. U(VI) diffused about 3mm, 1.5mm, and 1mm into the clay plug at ρ=1.3, 1.6, and 1.9g/cm(3), respectively...
October 11, 2016: Science of the Total Environment
Lucile Chatelain, Sarah White, Rosario Scopelliti, Marinella Mazzanti
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(UO2 )5 (μ3 -O)5 (PhCOO)5 (Py)7 ] (1)...
October 14, 2016: Angewandte Chemie
Tobias Hollmer, Winfried Petry
(99)Mo is the most widely used radioactive isotope in nuclear medicine. Its main production route is the fission of uranium. A major challenge for a reliable supply is the conversion from highly enriched uranium (HEU) to low enriched uranium (LEU). A promising candidate to realize this conversion is the cylindrical LEU irradiation target. The target consists of a uranium foil encapsulated between two coaxial aluminum cladding cylinders. This target allows a separate processing of the irradiated uranium foil and the cladding when recovering the (99)Mo...
October 6, 2016: Applied Radiation and Isotopes
John J Kiernicki, Maryline G Ferrier, Juan S Lezama Pacheco, Henry S La Pierre, Benjamin W Stein, Matthias Zeller, Stosh A Kozimor, Suzanne C Bart
Arylazide and diazene activation by highly reduced uranium(IV) complexes bearing trianionic redox-active pyridine(diimine) ligands, [Cp(P)U((Mes)PDI(Me))]2 (1-Cp(P)), Cp*U((Mes)PDI(Me))(THF) (1-Cp*) (Cp(P) = 1-(7,7-dimethylbenzyl)cyclopentadienide; Cp* = η(5)-1,2,3,4,5-pentamethylcyclopentadienide), and Cp*U((t)Bu-(Mes)PDI(Me)) (THF) (1-(t)Bu) (2,6-((Mes)N═CMe)2-p-R-C5H2N, Mes = 2,4,6-trimethylphenyl; R = H, (Mes)PDI(Me); R = C(CH3)3, (t)Bu-(Mes)PDI(Me)), has been investigated. While 1-Cp* and 1-Cp(P) readily reduce N3R (R = Ph, p-tolyl) to form trans-bis(imido) species, Cp(P)U(NAr)2((Mes)PDI(Me)) (Ar = Ph, 2-Cp(P); Ar = p-Tol, 3-Cp(P)) and Cp*U(NPh)2((Mes)PDI(Me)) (2-Cp*), only 1-Cp* can cleave diazene N═N double bonds to form the same product...
October 12, 2016: Journal of the American Chemical Society
Stéphane Grison, Gaëlle Favé, Matthieu Maillot, Line Manens, Olivia Delissen, Éric Blanchardon, Isabelle Dublineau, Jocelyne Aigueperse, Sandra Bohand, Jean-Charles Martin, Maâmar Souidi
INTRODUCTION: Data are sparse about the potential health risks of chronic low-dose contamination of humans by uranium (natural or anthropogenic) in drinking water. Previous studies report some molecular imbalances but no clinical signs due to uranium intake. OBJECTIVES: In a proof-of-principle study, we reported that metabolomics is an appropriate method for addressing this chronic low-dose exposure in a rat model (uranium dose: 40 mg L(-1); duration: 9 months, n = 10)...
2016: Metabolomics: Official Journal of the Metabolomic Society
Jordann A L Wells, Megan L Seymour, Markéta Suvova, Polly L Arnold
Two lower-oxidation state uranium cations can be readily combined in a robust, yet flexible and derivatisable, tetraaryloxide ligand framework, affording a new platform at which to use the multi-electron reductive capacity of the two actinide centres.
October 12, 2016: Dalton Transactions: An International Journal of Inorganic Chemistry
Xiaofang Wang, Zhong Long, Ren Bin, Ruilong Yang, Qifa Pan, Fangfang Li, Lizhu Luo, Yin Hu, Kezhao Liu
Uranium nitrides are among the most promising fuels for Generation IV nuclear reactors, but until now, very little has been known about their thermal stability properties under nonequilibrium conditions. In this work, thermal decomposition of nitrogen-rich uranium nitride (denoted as UN2-x) under ultrahigh-vacuum (UHV) conditions was investigated by thermal desorption spectroscopy (TDS). It has been shown that the nitrogen TDS spectrum consists of two peaks at about 723 and 1038 K. The X-ray diffraction, scanning electron microscopy, and X-ray photoelectron microscopy results indicate that UN2-x (UN2 phase) decomposed into the α-U2N3 phase in the first step and the α-U2N3 phase decomposed into the UN phase in the second step...
October 11, 2016: Inorganic Chemistry
Shu-Xian Hu, John K Gibson, Wan-Lu Li, Michael J Van Stipdonk, Jonathan Martens, Giel Berden, Britta Redlich, Jos Oomens, Jun Li
Understanding of the nature and extent of chemical bonding in uranyl coordination complexes is crucial for the design of new ligands for nuclear waste separation, uranium extraction from seawater, and other applications. We report here the synthesis, infrared spectroscopic characterization, and quantum chemical studies of a molecular uranyl-di-15-crown-5 complex. The structure and bonding of this unique complex featuring a distinctive 6-fold coplanar coordination staggered sandwich structure and an unusual non-perpendicular orientation of the uranyl moiety are evaluated using density functional theory and chemical bonding analyses...
October 11, 2016: Chemical Communications: Chem Comm
Joseph Hufton, John H Harding, Maria E Romero-González
Bacterial extra polymeric substances (EPS) have been associated with the extracellular precipitation of uranium. Here we report findings on the biomineralisation of uranium, with extracellular DNA (eDNA) used as a model biomolecule representative of EPS. The complexation and precipitation of eDNA with uranium were investigated as a function of pH, ionic strength and varying concentrations of reactants. The role of phosphate moieties in the biomineralisation mechanism was studied by enzymatically releasing phosphate (ePO4) from eDNA compared to abiotic phosphate (aPO4)...
October 11, 2016: Physical Chemistry Chemical Physics: PCCP
Xiaofeng Guo, Christian Lipp, Eitan Tiferet, Antonio Lanzirotti, Matthew Newville, Mark H Engelhard, Di Wu, Eugene S Ilton, Stephen R Sutton, Hongwu Xu, Peter C Burns, Alexandra Navrotsky
Heating a mixture of uranyl(vi) nitrate and tantalum(v) oxide in the molar ratio of 2 : 3 to 1400 °C resulted in the formation of a new compound, UTa3O10. The honey colored to yellow brown crystals of UTa3O10 crystallize in an orthorhombic structure with the space group Fddd (no. 70), lattice parameters a = 7.3947(1), b = 12.7599(2), c = 15.8156(2) Å, and Z = 8. Vertex sharing [TaO6](7-) octahedra of two crystallographically distinct Ta cations form a three dimensional tantalate framework. Within this framework, six membered rings of [TaO6](7-) octahedra are formed within the (001) plane...
September 15, 2016: Dalton Transactions: An International Journal of Inorganic Chemistry
Anwei Chen, Cui Shang, Jihai Shao, Jiachao Zhang, Hongli Huang
Remediating uranium contamination is of worldwide interest because of the increasing release of uranium from mining and processing, nuclear power leaks, depleted uranium components in weapons production and disposal, and phosphate fertilizer in agriculture activities. Iron-based technologies are attractive because they are highly efficient, inexpensive, and readily available. This paper provides an overview of the current literature that addresses the application of iron-based technologies in the remediation of sites with elevated uranium levels...
October 5, 2016: Science of the Total Environment
Alasdair Formanuik, Fabrizio Ortu, Christopher Inman, Andrew Kerridge, Ludovic Castro, Laurent Maron, David Paul Mills
Improving our comprehension of diverse CO2 activation pathways is of vital importance for the widespread future utilization of an abundant greenhouse gas. CO2 activation by uranium(III) complexes is now relatively well understood, with oxo/carbonate formation predominating as CO2 is readily reduced to CO, but isolated thorium(III) CO2 activation is unprecedented. We show that the thorium(III) complex, [Th(Cp'')3] (1, Cp'' = {C5H3(SiMe3)2-1,3}), reacts with CO2 to give the mixed oxalate-carboxylate thorium(IV) complex [{Th(Cp'')2[κ2-O2C{C5H3-3,3'-(SiMe3)2}]}2(µ-κ2:κ2-C2O4)] (3)...
October 7, 2016: Chemistry: a European Journal
Thi-Ngoc Suong Huynh, Claude Vidaud, Agnès Hagège
During long-term exposure, uranium accumulates in bone. Since uranium in U(vi) complexes shares similar coordination properties to calcium, this toxicant is assumed to be exchanged with calcium ions at the surfaces of bone mineral crystals. Recently, two proteins involved in bone turnover, fetuin A and osteopontin, were shown to exhibit a high affinity for U(vi). A common biochemical feature of both fetuin A and osteopontin is their inhibiting role in calcium phosphate precipitation. Therefore it is conceivable that complexation of U(vi) with these proteins may alter their interaction with calcium and/or calcium phosphate...
September 30, 2016: Metallomics: Integrated Biometal Science
Xiumei Song, Lichao Tan, Xiaojun Sun, Huiyuan Ma, Lin Zhu, Xiaoqing Yi, Qiang Dong, Junyu Gao
A hierarchical structure of NiCo2O4@rGO composite has been fabricated, with its structure and morphology well characterized by XRD, TEM, XPS and BET. The results proved that the NiCo2O4 nanosheets grow uniformly on both sides of the graphene sheets. In batch adsorption experiments, the effects of equilibrium time, pH and temperature on uranium(vi) adsorption were investigated. The main results show that the NiCo2O4@rGO composite has a higher affinity towards the uptake of uranium(vi) from aqueous solutions...
September 30, 2016: Dalton Transactions: An International Journal of Inorganic Chemistry
Lei Zhang, Bo Fang, Guohua Hou, Lin Ai, Wanjian Ding, Marc D Walter, Guofu Zi
The uranium metallacyclopropene (η(5)-C5Me5)2U[η(2)-C2(SiMe3)2] (1) reacts with various small unsaturated organic molecules. For example, replacement of bis(trimethylsilyl)acetylene occurs when complex 1 is exposed to alkynes, conjugated alkenes, nitriles and quinones. Reaction of 1 with internal phenyl(alkyl)acetylene PhC[triple bond, length as m-dash]CMe selectively yields the Cs symmetric uranium metallacyclopentadiene (η(5)-C5Me5)2U[η(2)-C(Ph)[double bond, length as m-dash]C(Me)-C(Ph)[double bond, length as m-dash]C(Me)] (6) after the loss of bis(trimethylsilyl)acetylene, while treatment of 1 with phenyl(silyl)acetylenes (PhC[triple bond, length as m-dash]CR, R = SiHMe2, SiMe3) gives the corresponding C2v symmetric isomers (η(5)-C5Me5)2U[η(2)-C(R)[double bond, length as m-dash]C(Ph)-C(Ph)[double bond, length as m-dash]C(R)] (R = SiHMe2 (7), SiMe3 (8))...
October 18, 2016: Dalton Transactions: An International Journal of Inorganic Chemistry
Zhen Qin, Siwei Shi, Chuting Yang, Jun Wen, Jianping Jia, Xiaofang Zhang, Haizhu Yu, Xiaolin Wang
Sequestering uranium from the ocean is a promising solution to fulfill the demand for nuclear energy. Motivated by this purpose, a series of amidoxime ligands and their analogs have been developed with high absorption capacity and selectivity. An in-depth understanding of the structural information of the uranyl-ligand complexes is essential to improve the performance of the ligands. Herein, we have studied the coordination of three amidoxime ligands (6-methoxyl-naphtha-2-amidoxime, NAO; glutarimidedioxime, GIO; and gluardiamidoxime, GDO) with uranyl in the gas phase by mass spectrometry...
October 18, 2016: Dalton Transactions: An International Journal of Inorganic Chemistry
A Baeza, A Salas, J Guillén, A Muñoz-Serrano, M Á Ontalba-Salamanca, M C Jiménez-Ramos
The occurrence of naturally occurring radionuclides in drinking water can pose health hazards in some populations, especially taking into account that routine procedures in Drinking Water Treatment Plants (DWTPs) are normally unable to remove them efficiently from drinking water. In fact, these procedures are practically transparent to them, and in particular to radium. In this paper, the characterization and capabilities of a patented filter designed to remove radium from drinking water with high efficiency is described...
October 3, 2016: Chemosphere
Yang Li, Lei Wang, Bo Li, Meicheng Zhang, Rui Wen, Xinghua Guo, Xing Li, Ji Zhang, Shoujian Li, Lijian Ma
A new strategy combining pore-free matrix and cooperative-chelating was proposed in the present paper in order to effectively avoid undesired non-selective physical adsorption and intra-particle diffusion caused by pores and voids in porous sorbents, and to greatly enhance uranium-chelating capability based on hyperbranched amidoxime ligands on the surface of nanodiamond particles. Thus a pore-free, amidoxime-terminated hyperbranched nanodiamond (ND-AO) was designed and synthesized. The experimental results demonstrate that the strategy endows the as-synthesized ND-AO with following expected features: (1) distinctively high uranium selectivity (SU = qe-U /qe-tol ×100 %) from over 80% to nearly 100 % over the whole weak acidity range (pH < 4...
October 4, 2016: ACS Applied Materials & Interfaces
Mark A Lashley, Alexander S Ivanov, Vyacheslav S Bryantsev, Sheng Dai, Robert D Hancock
Studies of the complexation of new promising ligands with uranyl (UO2(2+)) and other seawater cations can aid the development of more efficient, selective, and robust sorbents for the recovery of uranium from seawater. In this work, we propose that the ligand design principles based on structural preorganization can be successfully applied to obtain a dramatic enhancement in UO2(2+) ion binding affinity and selectivity. This concept is exemplified through the investigation of the complexes of UO2(2+), VO2(+), and VO(2+) with the highly preorganized ligand 1,10-phenanthroline-2,9-dicarboxylic acid (PDA) using a combination of fluorescence and absorbance techniques, along with density functional theory (DFT) calculations...
October 17, 2016: Inorganic Chemistry
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