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https://www.readbyqxmd.com/read/28195738/thorium-and-uranium-hydride-phosphorus-and-arsenic-bearing-molecules-with-single-and-double-actinide-pnictogen-and-bridged-agostic-hydrogen-bonds
#1
Lester Andrews, Han-Gook Cho, K Sahan Thanthiriwatte, David A Dixon
Thorium atoms from laser ablation react with phosphine during condensation in excess argon to produce two new infrared absorptions at 1467.2 and 1436.6 cm(-1) near weak bands for ThH and ThH2, which increase on annealing to 25 and 30 K, indicating spontaneous reactions. Analogous experiments with uranium produced two similar bands at 1473.4 and 1456.7 cm(-1) above UH at 1423.8 cm(-1) and another absorption at 1388.2 cm(-1). Electronic structure calculations at the coupled cluster CCSD(T) for Th and density functional theory calculations for U as well as their proximity to other actinide hydride absorptions support assignments of these bands to the simplest molecules HP═ThH2, HP═UH2, and PH2-UH...
February 14, 2017: Inorganic Chemistry
https://www.readbyqxmd.com/read/28195703/mass-spectrometric-determination-of-uranium-and-thorium-in-high-radiopurity-polymers-using-ultra-low-background-electroformed-copper-crucibles-for-dry-ashing
#2
Isaac J Arnquist, Eric W Hoppe, Mary Bliss, Jay W Grate
A rapid new method for determining the U and Th mass concentrations in high radiopurity plastics is described, consisting of 1) dry ashing the plastic sample and tracers in low mass crucibles made of ultra low background electroformed copper (ULB EF-Cu) foil cut and folded into boats, 2) dissolving both the ash and the boat in acid, 3) performing a column separation to remove copper, and 4) determining the elements of interest by isotope dilution mass spectrometry. This method was demonstrated on both unfluorinated and fluorinated plastics, demonstrating high tracer recoveries and detection limits to pg/g (i...
February 14, 2017: Analytical Chemistry
https://www.readbyqxmd.com/read/28191940/thorium-chemistry-in-oxo-tellurium-system-under-extreme-conditions
#3
Bin Xiao, Philip Kegler, Dirk Bosbach, Evgeny V Alekseev
Through the use of a high-temperature/high-pressure synthesis method, four thorium oxo-tellurium compounds with different tellurium valence states were isolated. The novel inorganic phases illustrate the intrinsic complexity of the actinide tellurium chemistry under extreme conditions of pressure and temperature. Th2Te3O11 is the first instance of a mixed-valent oxo-tellurium compound, and at the same time, Te exhibits three different coordination environments (Te(IV)O3, Te(IV)O4, and Te(VI)O6) within a single structure...
February 13, 2017: Inorganic Chemistry
https://www.readbyqxmd.com/read/28161042/factors-affecting-atmospheric-radon-concentration-human-health
#4
D E Tchorz-Trzeciakiewicz, M Kłos
We studied the influence of terrain, geology and weather condition on radon concentration in the atmosphere and occurrence of radon density currents. The survey was carried out in Kowary (SW Poland) and in the spoil tip formed during uranium mining. The measurements of radon concentration were performed using SSNTD LR-115. The measurements of uranium thorium and potassium content in soil were carried out using gamma ray spectrometer Exploranium RS-230. We noticed that terrain and stability of weather condition had significant impact on atmospheric radon concentration...
February 1, 2017: Science of the Total Environment
https://www.readbyqxmd.com/read/28155857/the-inverse-trans-influence-in-tetravalent-lanthanide-and-actinide-bis-carbene-complexes
#5
Matthew Gregson, Erli Lu, David P Mills, Floriana Tuna, Eric J L McInnes, Christoph Hennig, Andreas C Scheinost, Jonathan McMaster, William Lewis, Alexander J Blake, Andrew Kerridge, Stephen T Liddle
Across the periodic table the trans-influence operates, whereby tightly bonded ligands selectively lengthen mutually trans metal-ligand bonds. Conversely, in high oxidation state actinide complexes the inverse-trans-influence operates, where normally cis strongly donating ligands instead reside trans and actually reinforce each other. However, because the inverse-trans-influence is restricted to high-valent actinyls and a few uranium(V/VI) complexes, it has had limited scope in an area with few unifying rules...
February 3, 2017: Nature Communications
https://www.readbyqxmd.com/read/28091341/correlation-between-infectious-disease-and-soil-radiation-in-japan-an-exploratory-study-using-national-sentinel-surveillance-data
#6
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
https://www.readbyqxmd.com/read/28079075/hydroclimate-changes-across-the-amazon-lowlands-over-the-past-45-000-years
#7
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
https://www.readbyqxmd.com/read/28059763/permanent-human-occupation-of-the-central-tibetan-plateau-in-the-early-holocene
#8
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
https://www.readbyqxmd.com/read/28056169/concomitant-leaching-and-electrochemical-extraction-of-rare-earth-elements-from-monazite
#9
Synthia Maes, Wei-Qin Zhuang, Korneel Rabaey, Lisa Alvarez-Cohen, Tom Hennebel
Rare earth elements (REEs) have become increasingly important in modern day technologies. Unfortunately, their recycling is currently limited, and the conventional technologies for their extraction and purification are exceedingly energy and chemical intensive. New sustainable technologies for REE extraction from both primary and secondary resources would be extremely beneficial. This research investigated a two-stage recovery strategy focused on the recovery of neodymium (Nd) and lanthanum (La) from monazite ore that combines microbially based leaching (using citric acid and spent fungal supernatant) with electrochemical extraction...
January 18, 2017: Environmental Science & Technology
https://www.readbyqxmd.com/read/28049554/characterization-of-bauxite-residue-red-mud-for-235-u-238-u-232-th-and-40-k-using-neutron-activation-analysis-and-the-radiation-dose-levels-as-modeled-by-mcnp
#10
S Landsberger, A Sharp, S Wang, Y Pontikes, A H Tkaczyk
This study employs thermal and epithermal neutron activation analysis (NAA) to quantitatively and specifically determine absorption dose rates to various body parts from uranium, thorium and potassium. Specifically, a case study of bauxite residue (red mud) from an industrial facility was used to demonstrate the feasibility of the NAA approach for radiological safety assessment, using small sample sizes to ascertain the activities of (235)U, (238)U, (232)Th and (40)K. This proof-of-concept was shown to produce reliable results and a similar approach could be used for quantitative assessment of other samples with possible radiological significance...
December 31, 2016: Journal of Environmental Radioactivity
https://www.readbyqxmd.com/read/28034512/characterization-of-the-natural-radioactivity-of-the-first-deep-geothermal-doublet-in-flanders-belgium
#11
M Vasile, M Bruggeman, S Van Meensel, S Bos, B Laenen
Deep geothermal energy is a local energy resource that is based on the heat generated by the Earth. As the heat is continuously regenerated, geothermal exploitation can be considered as a renewable and, depending on the techniques used, a sustainable energy production system. In September 2015, the Flemish Institute for Technological Research (VITO) started drilling an exploration well targeting a hot water reservoir at a depth of about 3km on the Balmatt site near Mol. Geothermal hot water contains naturally occurring gases, chemicals and radionuclides at variable concentrations...
December 20, 2016: Applied Radiation and Isotopes
https://www.readbyqxmd.com/read/28013158/preparation-and-characterization-of-porous-reduced-graphene-oxide-based-inverse-spinel-nickel-ferrite-nanocomposite-for-adsorption-removal-of-radionuclides
#12
Lakshmi Prasanna Lingamdinne, Yu-Lim Choi, Im-Soon Kim, Jae-Kyu Yang, Janardhan Reddy Koduru, Yoon-Young Chang
For the removal of uranium(VI) (U(VI)) and thorium(IV) (Th(IV)), graphene oxide based inverse spinel nickel ferrite (GONF) nanocomposite and reduced graphene oxide based inverse spinel nickel ferrite (rGONF) nanocomposite were prepared by co-precipitation of GO with nickel and iron salts in one pot. The spectral characterization analyses revealed that GONF and rGONF have a porous surface morphology with an average particle size of 41.41nm and 32.16nm, respectively. The magnetic property measurement system (MPMS) studies confirmed the formation of ferromagnetic GONF and superparamagnetic rGONF...
December 20, 2016: Journal of Hazardous Materials
https://www.readbyqxmd.com/read/28009936/double-reduction-of-4-4-bipyridine-and-reductive-coupling-of-pyridine-by-two-thorium-iii-single-electron-transfers
#13
Alasdair Formanuik, Fabrizio Ortu, Jingjing Liu, Lydia E Nodaraki, Floriana Tuna, Andrew Kerridge, David P Mills
The redox chemistry of uranium is burgeoning and uranium(III) complexes have been shown to promote many interesting synthetic transformations. However, their utility is limited by their reduction potentials, which are smaller than many non-traditional lanthanide(II) complexes. Thorium(III) has a greater redox potential so it should present unprecedented opportunities for actinide reactivity but as with uranium(II) and thorium(II) chemistry, these have not yet been fully realized. Herein we present reactivity studies of two equivalents of [Th(Cp'')3 ] (1, Cp''={C5 H3 (SiMe3 )2 -1,3}) with 4,4'-bipyridine or two equivalents of pyridine to give [{Th(Cp'')3 }2 {μ-(NC5 H4 )2 }] (2) and [{Th(Cp'')3 }2 {μ-(NC5 H5 )2 }] (3), respectively...
December 23, 2016: Chemistry: a European Journal
https://www.readbyqxmd.com/read/27931000/thorium-impact-on-tobacco-root-transcriptome
#14
Kateřina Mazari, Přemysl Landa, Sylva Přerostová, Karel Müller, Radomíra Vaňková, Petr Soudek, Tomáš Vaněk
Thorium is natural actinide metal with potential use in nuclear energetics. Contamination by thorium, originated from mining activities or spills, represents environmental risk due to its radioactivity and chemical toxicity. A promising approach for cleaning of contaminated areas is phytoremediation, which need to be based, however, on detail understanding of the thorium effects on plants. In this study we investigated transcriptomic response of tobacco roots exposed to 200μM thorium for one week. Thorium application resulted in up-regulation of 152 and down-regulation of 100 genes (p-value <0...
March 5, 2017: Journal of Hazardous Materials
https://www.readbyqxmd.com/read/27914775/assessment-of-background-gamma-radiation-levels-using-airborne-gamma-ray-spectrometer-data-over-uranium-deposits-cuddapah-basin-india-a-comparative-study-of-dose-rates-estimated-by-agrs-and-pgrs
#15
D Srinivas, V Ramesh Babu, I Patra, Shailesh Tripathi, M S Ramayya, A K Chaturvedi
The Atomic Minerals Directorate for Exploration and Research (AMD) has conducted high-resolution airborne gamma ray spectrometer (AGRS), magnetometer and time domain electromagnetic (TDEM) surveys for uranium exploration, along the northern margins of Cuddapah Basin. The survey area includes well known uranium deposits such as Lambapur-Peddagattu, Chitrial and Koppunuru. The AGRS data collected for uranium exploration is utilised for estimating the average absorbed rates in air due to radio-elemental (potassium in %, uranium and thorium in ppm) distribution over these known deposit areas...
February 2017: Journal of Environmental Radioactivity
https://www.readbyqxmd.com/read/27907882/thorium-229-quantified-in-historical-thorium-228-capsules
#16
Sven Boden, Koen Vints, Simone Cagno, Dominic Maertens, Karen Van Hecke, Thomas Cardinaels
Thorium-229 is a valuable, but scarce, radionuclide for nuclear clock applications or targeted alpha therapy. While it is mostly produced by the decay of (233)U, (229)Th can also be produced by neutron irradiation of (226)Ra. At SCK•CEN, capsules containing mainly (228)Th (by-product of (226)Ra irradiation) were characterized to quantify the present amounts of (229)Th, (228)Th, (227)Ac, (226)Ra with high resolution gamma spectroscopy, after a decay period of 40 years in which (228)Th has decayed. High purity (229)Th was quantified, and after recovery using radiochemical separation processes, it can be used to support ongoing research...
February 2017: Applied Radiation and Isotopes
https://www.readbyqxmd.com/read/27847956/uranium-iii-and-thorium-iv-alkyl-complexes-as-potential-starting-materials
#17
Andrew C Behrle, Alexander J Myers, Pokpong Rungthanaphatsophon, Wayne W Lukens, Charles L Barnes, Justin R Walensky
The synthesis and characterisation of a rare U(iii) alkyl complex, U[η(4)-Me2NC(H)C6H5]3, using the dimethylbenzylamine (DMBA) ligand has been accomplished. While attempting to prepare the U(iv) compound, reduction to the U(iii) complex occurred. In the analogous Th(iv) system, C-H bond activation of a methyl group of one dimethylamine was observed yielding Th[η(4)-Me2NC(H)C6H5]2[η(5)-(CH2)MeNC(H)C6H5] with a dianionic DMBA ligand. The utility of these complexes as starting materials has been analyzed using a bulky dithiocarboxylate ligand to yield tetravalent actinide species...
December 13, 2016: Chemical Communications: Chem Comm
https://www.readbyqxmd.com/read/27846529/response-to-comments-on-reconciliation-of-the-devils-hole-climate-record-with-orbital-forcing
#18
Gina E Moseley, Yuri V Dublyansky, R Lawrence Edwards, Kathleen A Wendt, Mathieu Pythoud, Pu Zhang, Hai Cheng, Yanbin Lu, Ronny Boch, Christoph Spötl
Winograd and Coplen question the thorium-230 distribution model proposed to explain the age bias observed with increasing depth during Termination II. We have evaluated both criticisms and find that all samples display virtually identical fabrics, argue that the modern setting is not analogous to the conditions during Termination II, and reiterate the robustness of our age models. Our conclusions remain unchanged.
October 21, 2016: Science
https://www.readbyqxmd.com/read/27846528/comment-on-reconciliation-of-the-devils-hole-climate-record-with-orbital-forcing
#19
Tyler B Coplen
Moseley et al's (Reports, 8 January 2016, p. 165) preferred-Termination-II age is subjective, as evidenced by variation in their Termination-II ages of 2500 years per meter. Termination-II-age bias decreases to zero at ~1.5 meters below the present-day water table, if one assumes linear variation with core-sample height. Maintaining the required gradient of thorium isotope (230)Th over 3.6 meters for 1000 years, much less 10,000 years, seems exceedingly unlikely.
October 21, 2016: Science
https://www.readbyqxmd.com/read/27846527/comment-on-reconciliation-of-the-devils-hole-climate-record-with-orbital-forcing
#20
Isaac J Winograd
Moseley et al (Reports, 8 January 2016, p. 165) postulate an increase in dissolved thorium isotope (230)Th with depth below the water table as the explanation for the differing ages of Termination II. Flow of geothermal water through the Devils Hole caverns precludes this explanation. Deposition of younger secondary calcite into the initial porosity of the calcite comprising their cores is a plausible alternate explanation.
October 21, 2016: Science
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