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Jo Ellen Hinck, Danielle Cleveland, William G Brumbaugh, Greg Linder, Julia Lankton
The risks to wildlife and humans from uranium (U) mining in the Grand Canyon watershed are largely unknown. In addition to U, other co-occurring ore constituents contribute to risks to biological receptors depending on their toxicological profiles. This study characterizes the pre-mining concentrations of total arsenic (As), cadmium (Cd), copper (Cu), lead (Pb), mercury (Hg), nickel (Ni), selenium (Se), thallium (Tl), U, and zinc (Zn); radiation levels; and histopathology in biota (vegetation, invertebrates, amphibians, birds, and mammals) at the Canyon Mine...
February 2017: Environmental Monitoring and Assessment
S Inaida, T Tsuda, S Matsuno
We investigated the relationship between epidemics and soil radiation through an exploratory study using sentinel surveillance data (individuals aged <20 years) during the last three epidemic seasons of influenza and norovirus in Japan. We used a spatial analysis method of a geographical information system (GIS). We mapped the epidemic spreading patterns from sentinel incidence rates. We calculated the average soil radiation [dm (μGy/h)] for each sentinel site using data on uranium, thorium, and potassium oxide in the soil and examined the incidence rate in units of 0·01 μGy/h...
January 16, 2017: Epidemiology and Infection
Jichang Yu, Yanyan Liu, Jianwen Cai, Dale P Sandler, Haibo Zhou
We propose a cost-effective outcome-dependent sampling design for the failure time data and develop an efficient inference procedure for data collected with this design. To account for the biased sampling scheme, we derive estimators from a weighted partial likelihood estimating equation. The proposed estimators for regression parameters are shown to be consistent and asymptotically normally distributed. A criteria that can be used to optimally implement the ODS design in practice is proposed and studied. The small sample performance of the proposed method is evaluated by simulation studies...
November 2016: Journal of Statistical Planning and Inference
Tatiana Gritsaenko, Valérie Pierrefite-Carle, Thomas Lorivel, Véronique Breuil, Georges F Carle, Sabine Santucci-Darmanin
BACKGROUND: Uranium is a naturally occurring radionuclide ubiquitously present in the environment. The skeleton is the main site of uranium long-term accumulation. While it has been shown that natural uranium is able to perturb bone metabolism through its chemical toxicity, its impact on bone resorption by osteoclasts has been poorly explored. Here, we examined for the first time in vitro effects of natural uranium on osteoclasts. METHODS: The effects of uranium on the RAW 264...
January 9, 2017: Biochimica et Biophysica Acta
R Eigl, P Steier, K Sakata, A Sakaguchi
The first extensive study on (236)U in the North Pacific Ocean has been conducted. The vertical distribution of (236)U/(238)U isotopic ratios and the (236)U concentrations were analysed on seven depth profiles, and large variations with depth were found. The range of (236)U/(238)U isotopic ratios was from (0.09 ± 0.03) × 10(-10) to (14.1 ± 2.2) × 10(-10), which corresponds to (236)U concentrations of (0.69 ± 0.24) × 10(5) atoms/kg and (119 ± 21) × 10(5) atoms/kg, respectively. The variations in (236)U concentrations could mainly be attributed to the different water masses in the North Pacific Ocean and their formation processes...
January 12, 2017: Journal of Environmental Radioactivity
Su Jung An, Hee Seo, Chaehun Lee, Seong-Kyu Ahn, Se-Hwan Park, Jeong-Hoe Ku
The PRIDE (PyRoprocessing Integrated inactive DEmonstration) is an engineering-scale pyroprocessing test-bed facility that utilizes depleted uranium (DU) instead of spent fuel as a process material. As part of the ongoing effort to enhance pyroprocessing safeguardability, UNDA (Unified Non-Destructive Assay), a system integrating three different non-destructive assay techniques, namely, neutron, gamma-ray, and mass measurement, for nuclear material accountancy (NMA) was developed. In the present study, UNDA's NMA capability was evaluated by measurement of the weight, (238)U mass, and U enrichment of oxide-reduction-process feed material (i...
December 30, 2016: Applied Radiation and Isotopes
Miriam Bader, Katharina Müller, Harald Foerstendorf, Björn Drobot, Matthias Schmidt, Niculina Musat, Juliet S Swanson, Donald T Reed, Thorsten Stumpf, Andrea Cherkouk
The interactions of two extremely halophilic archaea with uranium were investigated at high ionic strength as a function of time, pH and uranium concentration. Halobacterium noricense DSM-15987 and Halobacterium sp. putatively noricense, isolated from the Waste Isolation Pilot Plant repository, were used for these investigations. The kinetics of U(VI) bioassociation with both strains showed an atypical multistage behavior, meaning that after an initial phase of U(VI) sorption, an unexpected interim period of U(VI) release was observed, followed by a slow reassociation of uranium with the cells...
December 27, 2016: Journal of Hazardous Materials
Lan Ling, Wei-Xian Zhang
A nanostructure-based mechanism is presented on the enrichment, separation and immobilization of arsenic with nanoscale Zero-Valent Iron (nZVI). The As-Fe reactions are studied with Spherical Aberration Corrected Scanning Transmission Electron Microscopy (Cs-STEM). Near atomic-resolution (<1 nm3) electron tomography discovers a thin continuous layer (23±3 Å) of elemental arsenic sandwiched between the iron oxide shell and the zero-valent iron core. This points to a unique mechanism of nano-encapsulation and proves that the outer layer, especially the Fe(0)/oxide interface is the edge of the As-Fe reactions...
January 12, 2017: Environmental Science & Technology
Xianfeng Wang, R Lawrence Edwards, Augusto S Auler, Hai Cheng, Xinggong Kong, Yongjin Wang, Francisco W Cruz, Jeffrey A Dorale, Hong-Wei Chiang
Reconstructing the history of tropical hydroclimates has been difficult, particularly for the Amazon basin-one of Earth's major centres of deep atmospheric convection. For example, whether the Amazon basin was substantially drier or remained wet during glacial times has been controversial, largely because most study sites have been located on the periphery of the basin, and because interpretations can be complicated by sediment preservation, uncertainties in chronology, and topographical setting. Here we show that rainfall in the basin responds closely to changes in glacial boundary conditions in terms of temperature and atmospheric concentrations of carbon dioxide...
January 11, 2017: Nature
Stephen Liddle, Peter Cleaves, Christos Kefalidis, Benedict Gardner, Floriana Tuna, Eric McInnes, William Lewis, Laurent Maron
We report the reactivity of terminal uranium(V/VI)-nitrides with CE2 (E = O, S), where we observe well-defined C=E cleavage followed by zero-, one-, and two-electron redox events. The uranium(V)-nitride [U(TrenTIPS)(N)][K(B15C5)2] [1, TrenTIPS = N(CH2CH2NSiPri3)3; B15C5 = benzo-15-crown-5] reacts with CO2 to give [U(TrenTIPS)(O)(NCO)][K(B15C5)2] (3), whereas the uranium(VI)-nitride [U(TrenTIPS)(N)] (2) reacts with CO2 to give isolable [U(TrenTIPS)(O)(NCO)] (4); complex 4 rapidly decomposes to known [U(TrenTIPS)(O)] (5) with concomitant formation of N2 and CO proposed, with the latter trapped as a vanadocene adduct...
January 11, 2017: Chemistry: a European Journal
Mateusz Dembowski, Varinia Bernales, Jie Qiu, Sarah Hickam, Gabriel Gaspar, Laura Gagliardi, Peter C Burns
Combination of uranium, peroxide, and mono- (Na, K) or divalent (Mg, Ca, Sr) cations under alkaline aqueous conditions results in the rapid formation of anionic uranyl triperoxide monomers (UTs), (UO2(O2)3)(4-), exhibiting unique Raman signatures. Electronic structure calculations were decisive for the interpretation of the spectra and assignment of unexpected signals associated with vibrations of the uranyl and peroxide ions. Assignments were verified by (18)O isotopic labeling of the uranyl ions supporting the computational-based interpretation of the experimentally observed peaks and the assignment of a novel asymmetric vibration of the peroxide ligands, v2(O2(2-))...
January 11, 2017: Inorganic Chemistry
Kathryn M Peruski, Varinia Bernales, Mateusz Dembowski, Haylie L Lobeck, Kristi L Pellegrini, Ginger E Sigmon, Sarah Hickam, Christine M Wallace, Jennifer E S Szymanowski, Enrica Balboni, Laura Gagliardi, Peter C Burns
Uranium concentrations as high as 2.94 × 10(5) parts per million (1.82 mol of U/1 kg of H2O) occur in water containing nanoscale uranyl cage clusters. The anionic cage clusters, with diameters of 1.5-2.5 nm, are charge-balanced by encapsulated cations, as well as cations within their electrical double layer in solution. The concentration of uranium in these systems is impacted by the countercations (K, Li, Na), and molecular dynamics simulations have predicted their distributions in selected cases. Formation of uranyl cages prevents hydrolysis reactions that would result in formation of insoluble uranyl solids under alkaline conditions, and these spherical clusters reach concentrations that require close packing in solution...
January 11, 2017: Inorganic Chemistry
Sharon E Bone, James J Dynes, John Cliff, John R Bargar
Uranium is an important carbon-free fuel source and environmental contaminant that accumulates in the tetravalent state, U(IV), in anoxic sediments, such as ore deposits, marine basins, and contaminated aquifers. However, little is known about the speciation of U(IV) in low-temperature geochemical environments, inhibiting the development of a conceptual model of U behavior. Until recently, U(IV) was assumed to exist predominantly as the sparingly soluble mineral uraninite (UO2+x) in anoxic sediments; however, studies now show that this is not often the case...
January 9, 2017: Proceedings of the National Academy of Sciences of the United States of America
Grzegorz Kosior, Eiliv Steinnes, Aleksandra Samecka-Cymerman, Syverin Lierhagen, Krzysztof Kolon, Agnieszka Dołhańczuk-Śródka, Zbigniew Ziembik
The past uranium/polymetallic mining activities in the Sudety (SW Poland) left abandoned mines, pits, and dumps of waste rocks with trace elements and radionuclides which may erode or leach out and create a potential risk for the aquatic ecosystem, among others. In the present work four rivers affected by effluents from such mines were selected to evaluate the application of aquatic mosses for the bioindication of 56 elements. Naturally growing F. antipyretica and P. riparioides were compared with transplanted samples of the same species...
November 5, 2016: Chemosphere
Kewin Gombeau, Jean-Paul Bourdineaud, Jean-Luc Ravanat, Olivier Armant, Virginie Camilleri, Isabelle Cavalie, Magali Floriani, Christelle Adam-Guillermin
This study investigated the effects of adult zebrafish exposure to a nominal concentration of 20μgL(-1) of depleted uranium (DU) for six days upon DNA methylation, gene expression and the appearance of histopathological damage in their progeny. In the embryos at the 2-8 cell stage, the parental exposure induced significant DU accumulation, with levels seven times higher than those measured in the control embryos, but in larvae 96h post-fertilisation (hpf), uranium concentration had already returned to a level identical to that of the control larvae...
December 8, 2016: Aquatic Toxicology
Li-Yong Yuan, Lin Zhu, Chengliang Xiao, Qun-Yan Wu, Nan Zhang, Ji-Pan Yu, Zhifang Chai, Wei-Qun Shi
The preorganized tetradentate phenanthrolineamide (DAPhen) ligand with hard-soft donors combined in the same molecule has been found to possess high extraction ability towards actinides over lanthanides from acidic aqueous solution in our previous work. Herein, we grafted phenanthrolineamide groups onto a large pore three-dimensional (3-D) cubic silica support by the reaction of DAPhen siloxane with KIT-6 substrate to prepare a novel uranium-selective sorbent, KIT-6-DAPhen. The as-synthesized sorbent was well characterized by SEM, HRTEM, N2 adsorption/desorption, XRD, FT-IR, 13C CP/MAS NMR, and TGA techniques, which confirmed the consummation of the functionalization...
January 9, 2017: ACS Applied Materials & Interfaces
Eungyeong Kim, Hyangsig Ahn, Ho Young Jo, Ji-Hun Ryu, Yong-Kwon Koh
Chlorite alteration and the U removal capacity of altered chlorite were investigated. Batch kinetic dissolution tests using clinochlore CCa-2 were conducted for 60days in aqueous solutions of various pHs and ionic strengths. Batch sorption tests using these altered chlorite samples were conducted for 48h with natural groundwater containing 3.06×10(-6)M U. Chlorite dissolution was influenced more by pHo than by the ionic strength of the solution. TEM analysis revealed Fe(oxy)hydroxide aggregates in the solid residue from the batch dissolution test with 0...
December 26, 2016: Journal of Hazardous Materials
M C Meyer, M S Aldenderfer, Z Wang, D L Hoffmann, J A Dahl, D Degering, W R Haas, F Schlütz
Current models of the peopling of the higher-elevation zones of the Tibetan Plateau postulate that permanent occupation could only have been facilitated by an agricultural lifeway at ~3.6 thousand calibrated carbon-14 years before present. Here we report a reanalysis of the chronology of the Chusang site, located on the central Tibetan Plateau at an elevation of ~4270 meters above sea level. The minimum age of the site is fixed at ~7.4 thousand years (thorium-230/uranium dating), with a maximum age between ~8...
January 6, 2017: Science
Songzi Kou, Zhongguang Yang, Fei Sun
Practical methods for oceanic uranium extraction have yet to be developed in order to tap into the vast uranium reserve in the ocean as an alternative energy. Here we present a protein hydrogel system containing a network of recently engineered super uranyl binding proteins (SUPs) that is assembled through thiol-maleimide click chemistry under mild conditions. Monodisperse SUP hydrogel microbeads fabricated by a microfluidic device further enable uranyl (UO22+) enrichment from seawater with great efficiency (Enrichment index, K = 2...
January 6, 2017: ACS Applied Materials & Interfaces
Slah Hidouri
Uranium has been defined in material research engineering field as one of the most energetic radioactive elements in the entire Mendeleev periodic table. The manipulation of uranium needs higher theories and sophisticated apparatus even in nuclear energy extraction or in many other chemical applications. Above the nuclear exploitation level, the chemical conventional approaches used, require a higher temperature and pressure to control the destination of ionic form. However, it has been discovered later that at biological scale, the manipulation of this actinide is possible under friendly conditions...
January 2017: Saudi Journal of Biological Sciences
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