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Laura Y Zheng, Alison P Sanders, Jeffrey M Saland, Robert O Wright, Manish Arora
BACKGROUND: Environmental chemical exposures have been implicated in pediatric kidney disease. No appraisal of the available evidence has been conducted on this topic. METHODS: We performed a systematic review of the epidemiologic studies that assessed association of environmental exposures with measures of kidney function and disease in pediatric populations. The search period went through July 2016. RESULTS: We found 50 studies that met the search criteria and were included in this systematic review...
July 17, 2017: Environmental Research
Marta Falcone, Lucile Chatelain, Rosario Scopelliti, Ivica Živković, Marinella Mazzanti
Molecular nitrogen (N2) is cheap and widely available, but its unreactive nature is a challenge when attempting to functionalize it under mild conditions with other widely available substrates (such as carbon monoxide, CO) to produce value-added compounds. Biological N2 fixation can do this, but the industrial Haber-Bosch process for ammonia production operates under harsh conditions (450 degrees Celsius and 300 bar), even though both processes are thought to involve multimetallic catalytic sites. And although molecular complexes capable of binding and even reducing N2 under mild conditions are known, with co-operativity between metal centres considered crucial for the N2 reduction step, the multimetallic species involved are usually not well defined, and further transformation of N2-binding complexes to achieve N-H or N-C bond formation is rare...
July 19, 2017: Nature
Manuel Alcaraz-Castaño, Javier Alcolea-González, Martin Kehl, Rosa-María Albert, Javier Baena-Preysler, Rodrigo de Balbín-Behrmann, Felipe Cuartero, Gloria Cuenca-Bescós, Fernando Jiménez-Barredo, José-Antonio López-Sáez, Raquel Piqué, David Rodríguez-Antón, José Yravedra, Gerd-Christian Weniger
INTRODUCTION AND OBJECTIVES: Although the Iberian Peninsula is a key area for understanding the Middle to Upper Paleolithic transition and the demise of the Neandertals, valuable evidence for these debates remains scarce and problematic in its interior regions. Sparse data supporting a late Neandertal persistence in the Iberian interior have been recently refuted and hence new evidence is needed to build new models on the timing and causes of Neandertal disappearance in inland Iberia and the whole peninsula...
2017: PloS One
Stephen Liddle, John Seed, Matthew Gregson, Floriana Tuna, Nicholas Chilton, Ashley Wooles, Eric McInnes
Neutral mesoionic carbenes (MICs) have emerged as an important class of carbene, however they are found only in the free form or ligated to a few d-block ions. Here, we report unprecedented f-block MIC complexes [M(N'')3{CN(Me)C(Me)N(Me)CH}] (M = U, Y, La, Nd; N'' = N(SiMe3)2). These complexes were prepared by a formal 1,4-proton migration reaction when the metal-triamides [M(N'')3] were treated with the N-heterocyclic olefin H2C=C(NMeCH)2, which constitutes a new, general way to prepare MIC complexes. Quantum chemical calculations on the 5f3 uranium(III) complex suggest the presence of a U=C donor-acceptor bond, composed of a MIC→U σ-component and a U(5f)→MIC(2p) π-back-bond, but for the d0f0 Y and La and 4f3 Nd congeners only MIC→M σ-bonding is found...
July 18, 2017: Angewandte Chemie
Nathanael Lampe, Vincent Breton, David Sarramia, Télesphore Sime-Ngando, David G Biron
Biological experiments conducted in underground laboratories over the last decade have shown that life can respond to relatively small changes in the radiation background in unconventional ways. Rapid changes in cell growth, indicative of hormetic behaviour and long-term inheritable changes in antioxidant regulation have been observed in response to changes in the radiation background that should be almost undetectable to cells. Here, we summarize the recent body of underground experiments conducted to date, and outline potential mechanisms (such as cell signalling, DNA repair and antioxidant regulation) that could mediate the response of cells to low radiation backgrounds...
August 2017: Evolutionary Applications
Junpei Imoto, Asumi Ochiai, Genki Furuki, Mizuki Suetake, Ryohei Ikehara, Kenji Horie, Mami Takehara, Shinya Yamasaki, Kenji Nanba, Toshihiko Ohnuki, Gareth T W Law, Bernd Grambow, Rodney C Ewing, Satoshi Utsunomiya
Highly radioactive cesium-rich microparticles (CsMPs) released from the Fukushima Daiichi Nuclear Power Plant (FDNPP) provide nano-scale chemical fingerprints of the 2011 tragedy. U, Cs, Ba, Rb, K, and Ca isotopic ratios were determined on three CsMPs (3.79-780 Bq) collected within ~10 km from the FDNPP to determine the CsMPs' origin and mechanism of formation. Apart from crystalline Fe-pollucite, CsFeSi2O6 · nH2O, CsMPs are comprised mainly of Zn-Fe-oxide nanoparticles in a SiO2 glass matrix (up to ~30 wt% of Cs and ~1 wt% of U mainly associated with Zn-Fe-oxide)...
July 14, 2017: Scientific Reports
Thomas Duignan, Jochen Autschbach, Enrique Batista, Ping Yang
The Kohn-Sham delocalization error (DE) is quantified in select uranium compounds for various functionals and shown to correlate with the magnitude of dative ligand donation into the 5f shell. Range seperated exchange (RSE) functionals are parameterized in order to minimize the DE and analyzed for their spectroscopic predictive capabilities. Valence excitation spectra of occupied 5f systems exhibit noticeable improvement upon parameterization, e.g. UCl6 - , UCl62 - , and UO2+. Less sensitivity to the reparameterization was observed for closed shell 5f systems and core excitation spectra...
July 12, 2017: Journal of Chemical Theory and Computation
Alice M Shumate, Kristin Yeoman, Tristan Victoroff, Kandace Evans, Roger Karr, Tami Sanchez, Akshay Sood, Anthony Scott Laney
OBJECTIVE: This study examines differences in chronic health outcomes between coal, uranium, metal, and nonmetal miners. METHODS: In a cross-sectional study using data from a health screening program for current and former New Mexico miners, log-binomial logistic regression models were used to estimate relative risks of respiratory and heart disease, cancer, osteoarthritis, and back pain associated with mining in each sector as compared with coal, adjusting for other relevant risk factors...
July 10, 2017: Journal of Occupational and Environmental Medicine
Edward D Hoegg, R Kenneth Marcus, David W Koppenaal, Jan Irvahn, George J Hager, Garret L Hart
RATIONALE: The field of highly accurate and precise isotope ratio analysis, for use in nonproliferation, has been dominated by thermal ionization and inductively coupled plasma mass spectrometry. While these techniques are considered the gold standard for isotope ratio analysis, a downsized instrument capable of accurately and precisely measuring U isotope ratios is desirable for field studies or in laboratories with limited infrastructure. METHODS: The developed system interfaces the liquid sampling, an atmospheric pressure glow discharge (LS-APGD) ion source, with a high resolution Exactive Orbitrap mass spectrometer...
July 11, 2017: Rapid Communications in Mass Spectrometry: RCM
V E A Post, S I Vassolo, C Tiberghien, D Baranyikwa, D Miburo
The potential use of groundwater for potable water supply can be severely compromised by natural contaminants such as uranium. The environmental mobility of uranium depends on a suite of factors including aquifer lithology, redox conditions, complexing agents, and hydrological processes. Uranium concentrations of up to 734μg/L are found in groundwater in northern Burundi, and the objective of the present study was to identify the causes for these elevated concentrations. Based on a comprehensive data set of groundwater chemistry, geology, and hydrological measurements, it was found that the highest dissolved uranium concentrations in groundwater occur near the shores of Lake Tshohoha South and other smaller lakes nearby...
July 7, 2017: Science of the Total Environment
Guohui Wang, Wooyong Um, Kirk J Cantrell, Michelle M V Snyder, Mark E Bowden, Mark B Triplett, Edgar C Buck
Chemical stabilization of tank residual waste is part of a Hanford Site tank closure strategy to reduce overall risk levels to human health and the environment. In this study, a set of column leaching experiments using tank C-104 residual waste were conducted to evaluate the leachability of uranium (U) and technetium (Tc) where grout and hydrated lime were applied as chemical stabilizing agents. The experiments were designed to simulate future scenarios where meteoric water infiltrates through the vadose zones into the interior of the tank filled with layers of grout or hydrated lime, and then contacts the residual waste...
June 26, 2017: Chemosphere
Leila Dolatyari, Mohammad Reza Yaftian, Sadegh Rostamnia, Mir Saeed Seyeddorraji
A solid-phase extraction based on a functionalized SBA-15, with the Schiff base ligand, ethylenediaminepropylesalicylaldimine (SBA/EnSA), was developed for the recovery and preconcentration of trace amounts of uranium(VI) in water samples, prior to its determination spectrophotometrically using ArsenazoIII. For optimizing the parameters affecting the adsorption step (pH, adsorbent dose and adsorption time) and those influencing the desorption process (concentration and volume of eluent and desorption time), a statistical technique response surface methodology (RSM) was employed...
2017: Analytical Sciences: the International Journal of the Japan Society for Analytical Chemistry
Ahmed Amara Konaté, Heping Pan, Huolin Ma, Zhen Qin, Bo Guo, Yao Yevenyo Ziggah, Claude Ernest Moussounda Kounga, Nasir Khan, Fodé Tounkara
The main purpose of the Wenchuan Earthquake Fault Scientific drilling project (WFSD) was to produce an in-depth borehole into the Yingxiu-Beichuan (YBF) and Anxian-Guanxian faults in order to gain a much better understanding of the physical and chemical properties as well as the mechanical faulting involved. Five boreholes, namely WFSD-1, WFSD-2, WFSD-3P, WFSD-3 and WFSD-4, were drilled during the project entirety. This study, therefore, presents first-hand WFSD-4 data on the lithology (original rocks) and fault rocks that have been obtained from the WFSD project...
June 28, 2017: Applied Radiation and Isotopes
T Vitova, I Pidchenko, D Fellhauer, P S Bagus, Y Joly, T Pruessmann, S Bahl, E Gonzalez-Robles, J Rothe, M Altmaier, M A Denecke, H Geckeis
One of the long standing debates in actinide chemistry is the level of localization and participation of the actinide 5f valence orbitals in covalent bonds across the actinide series. Here we illuminate the role of the 5f valence orbitals of uranium, neptunium and plutonium in chemical bonding using advanced spectroscopies: actinide M4,5 HR-XANES and 3d4f RIXS. Results reveal that the 5f orbitals are active in the chemical bonding for uranium and neptunium, shown by significant variations in the level of their localization evidenced in the spectra...
July 6, 2017: Nature Communications
Mark R Antonio, Ross J Ellis, Shanna L Estes, Mrinal K Bera
X-ray and electrochemical studies of organic phases obtained by the extraction of tetravalent cerium, Ce(iv), from aqueous nitric acid (3 M) with tri-n-butyl phosphate (TBP) in n-dodecane reveal a tetranuclear Ce(iv) structural motif. This finding is consistent with the results of previous liquid-liquid extraction (LLE) studies that implicate the aggregation of (Ce-O-Ce)(6+) dimers into multinuclear Ce(iv)·TBP solvates. The organic solution structures elaborated here for the Ce(iv)-HNO3-20% TBP-n-C12H26 system are correlated with multiscale phenomena-from the atomic level of the cerium coordination environment to the supramolecular scale of solute aggregates-in the organic phases, which are of relevance to the PUREX (Plutonium Uranium Reduction EXtraction) process...
July 5, 2017: Physical Chemistry Chemical Physics: PCCP
Stephen Liddle, Thomas Rookes, Benedict Gardner, Gabor Balazs, Matthew Gregson, Floriana Tuna, Ashley Wooles, Manfred Scheer
Reaction of [U(TrenTIPS)(PH2)] (1, TrenTIPS = N(CH2CH2NSiPri3)3) with C6H5CH2K and [U(TrenTIPS)(THF)][BPh4] (2) afforded a rare diuranium-parent-phosphinidiide complex [{U(TrenTIPS)}2(μ-PH)] (3). Treatment of 3 with C6H5CH2K and two equivalents of benzo-15-crown-5 ether (B15C5) gave the diuranium-μ-phosphido complex [{U(TrenTIPS)}2(μ-P)][K(B15C5)2] (4). Alternatively, reaction of [U(TrenTIPS)(PH)][Na(12C4)2] (5, 12C4 = 12-crown-4 ether) with [U{N(CH2CH2NSiMe2But)2CH2CH2NSi(Me)(CH2)(But)}] (6) produced the diuranium-μ-phosphido complex [{U(TrenTIPS)}(μ-P){U(TrenDMBS)}][Na(12C4)2] [7, TrenDMBS = N(CH2CH2NSiMe2But)3]...
July 5, 2017: Angewandte Chemie
J Lourenço, S Marques, F P Carvalho, J Oliveira, M Malta, M Santos, F Gonçalves, R Pereira, S Mendo
Active and abandoned uranium mining sites often create environmentally problematic situations, since they cause the contamination of all environmental matrices (air, soil and water) with stable metals and radionuclides. Due to their cytotoxic, genotoxic and teratogenic properties, the exposure to these contaminants may cause several harmful effects in living organisms. The Fish Embryo Acute Toxicity Test (FET) test was employed to evaluate the genotoxic and teratogenic potential of mine liquid effluents and sludge elutriates from a deactivated uranium mine...
June 30, 2017: Science of the Total Environment
Liang Du, Shicheng Li, Xiaolong Li, Ping Wang, Zhaoya Huang, Zhaoyi Tan, Chunli Liu, Jiali Liao, Ning Liu
Humic acid (HA)(1) is ubiquitous in the environment and is an important factor in the migration behavior of U(VI) in the geological medium. The present work investigated the effect of HA on the migration behavior of U(VI) using quartz column experiments at different pH values and in the presence of various anions. The U(VI) adsorption characteristics and speciation were also studied to illuminate further the migration behavior of U(VI). Our results indicated that, at pH 6.0, HA slightly increased the migration velocity of U(VI) during the initial phase and reduced the quantity of eluted U(VI) because of the formation of HA-U(VI)...
June 28, 2017: Journal of Environmental Radioactivity
Yong-Jun Ye, Yun-Feng Zhang, Xin-Tao Dai, De-Xin Ding
The particle size and heaped methods of exhalation media have important effects on physical parameters, such as the free radon production rate, porosity, permeability, and radon diffusion coefficient. However, existing methods for determining those parameters are too complex, and time-consuming. In this study, a novel, systematic determining method was proposed based on nuclide decay, radon diffusion migration theory, and the mass conservation law, and an associated experimental device was designed and manufactured...
June 26, 2017: Journal of Environmental Radioactivity
Ahmed R Elsalamouny, Osman A Desouky, Saad A Mohamed, Ahmed A Galhoum, Eric Guibal
A direct reaction is described to prepare hydrophobic α-aminomethylphosphonic acid as a novel chitosan-based material. It exhibits chelating properties for polyvalent metal ions such as U(VI) and Nd(III) ions. The new sorbent was fully characterized using Elemental analysis, scanning electron microscope (SEM) and FTIR spectra. Different parameters were examined in order to evaluate the optimum conditions for U(VI) and Nd(III) ions biosorption. Sorption mechanisms of metal ions were investigated using kinetic and isotherm models...
June 27, 2017: International Journal of Biological Macromolecules
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