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Christian Turra
Rare earth elements (REE) are a group of chemical elements that include lanthanoids (lanthanum to lutetium), scandium and yttrium. In the last decades, the REE demand in the industry and other areas has increased significantly. In general, REE have shown low concentrations in soils, plants, water and atmosphere, but they may accumulate in such environments due to anthropogenic inputs. In areas where there is REE contamination, the slow accumulation of these elements in the environment could become problematic...
December 15, 2017: International Journal of Environmental Health Research
Lei Yao, Wei Pan, Jian Luo, Xiaohui Zhao, Jing Cheng, Hiroki Nishijima
Nanocrystalline materials often exhibit extraordinary mechanical and physical properties, but their applications at elevated temperatures are impaired by the rapid grain growth. Moreover, the grain growth in nanocrystalline oxide nanofibers at high temperatures can occur at hundreds of degrees lower than that would occur in corresponding bulk nanocrystalline materials, which would eventually break the fibers. Herein, by characterizing a model system of scandia-stabilized zirconia (ScSZ) using hot-stage in-situ scanning transmission electron microscopy (STEM), we discover that the enhanced grain growth in nanofibers is initiated at the surface...
December 14, 2017: Nano Letters
Liping Fang, Ru Liu, Ji Li, Cuihong Xu, Li-Zhi Huang, Dongsheng Wang
An effective approach for eutrophication control and phosphate recovery remains a longstanding challenge. Herein, we present a new technique for phosphate sequestration in lake and phosphate recovery using novel magnetically recoverable magnetite/lanthanum hydroxide [M-La(OH)3] hybrids that can be prepared using a simple one-pot synthesis method. Batch studies show that M-La(OH)3 exhibits a strong sorption towards phosphate with sorption capacities of up to 52.7 mg-P/g at pH 7.0 in water. A simple model indicates that the efficiency of M-La(OH)3 for phosphate sequestration in lake is significantly attenuated by 34-45% compared to that in water, due to interference from sediment particles...
December 5, 2017: Water Research
Fan Zhang, Huiqing Hu, Lihong Wang, Qing Zhou, Xiaohua Huang
Combined rare earth and acid rain pollution has become a new environmental problem, seriously affecting plant survival. The effects of these two kinds of pollutants on plant photosynthesis have been reported, but the micro mechanisms are not very clear. In this research, we studied the effects of lanthanum [La(III), 0.08, 1.20 and 2.40 mM] and acid rain (pH value = 2.5, 3.5 and 4.5) on the ATPase activity and gene transcription level and the functional element contents in rice leaf chloroplasts. The results showed that the combined 0...
December 1, 2017: Chemosphere
Masaya Iwamuro, Haruo Urata, Takehiro Tanaka, Seiji Kawano, Yoshiro Kawahara, Katsuhiko Kimoto, Hiroyuki Okada
In this case report, we describe two patients who showed a diffusely whitish mucosa in the posterior wall and the lesser curvature of the gastric body. The patients were serologically- and histopathologically-negative for Helicobacter pylori. Random biopsy specimens from the stomach revealed no regenerative changes, intestinal metaplasia, and/or foveolar hyperplasia in either of the patients. Although lanthanum deposition in the gastric mucosa has been reported to occur in close association with H. pylori-associated gastritis, our patients tested negative for H...
December 8, 2017: Internal Medicine
Li Sheng, Zhihui Zhao, Biquan Su, Caihong Tao, Wangli Jing
Two simple and sensitive kinetic-fluorometric methods have been developed for the determination of lanthanum(III): fluorescence quenching generated by the oxidation of safranine T or phenosafranine with potassium bromate in an acetate buffer solution. The rate of the oxidation reaction is significantly accelerated after adding lanthanum(III). A good linearity between the relative fluorescence intensity and lanthanum(III) is observed in the range of both 0.04 - 2.0 and 4.0 - 16 μg/mL. The detection limits have been 3...
2017: Analytical Sciences: the International Journal of the Japan Society for Analytical Chemistry
Qiannan Fang, Haohai Yu, Huaijin Zhang, Guochun Zhang, Jiyang Wang, Yicheng Wu
We demonstrated the output power enhancement of a self-frequency-doubled laser with Nd3+-doped lanthanum calcium borate La2CaB10O19 (Nd:LCB) crystals by selective excitation of its inequivalent active centers. When the Nd3+ ions located in the Ca2+ sites were excited in the Nd:LCB crystal, the fundamental laser at the wavelength of 1066 nm was successfully realized, which can keep the self-frequency-doubled wavelength away from the self-absorption peak of Nd3+ ions at about 523 nm. By optimizing the key parameters, the maximum output power of 801 mW was achieved with the frequency-doubling at the wavelength of 533 nm, and the enhancement of output power was about 7...
December 1, 2017: Optics Letters
Shui-Ping Yang, Wei Zhao, Pei-Pei Hu, Ke-Yang Wu, Zhi-Hong Jiang, Li-Ping Bai, Min-Min Li, Jin-Xiang Chen
Reactions of La(NO3)3·6H2O with the polar, tritopic quaternized carboxylate ligands N-carboxymethyl-3,5-dicarboxylpyridinium bromide (H3CmdcpBr) and N-(4-carboxybenzyl)-3,5-dicarboxylpyridinium bromide (H3CbdcpBr) afford two water-stable metal-organic frameworks (MOFs) of {[La4(Cmdcp)6(H2O)9]}n (1, 3D) and {[La2(Cbdcp)3(H2O)10]}n (2, 2D). MOFs 1 and 2 absorb the carboxyfluorescein (FAM)-tagged probe DNA (P-DNA) and quench the fluorescence of FAM via a photoinduced electron transfer (PET) process. The nonemissive P-DNA@MOF hybrids thus formed in turn function as sensing platforms to distinguish conservative linear, single-stranded RNA sequences of Sudan virus with high selectivity and low detection limits of 112 and 67 pM, respectively (at a signal-to-noise ratio of 3)...
December 7, 2017: Inorganic Chemistry
Emine Kılıçkaya Selvi, Uğur Şahin, Serkan Şahan
This method was developed for the determination of trace amounts of aluminum(III) in dialysis concentrates using atomic absorption spectrometry after coprecipitation with lanthanum phosphate. The analytical parameters that influenced the quantitative coprecipitation of analyte including amount of lanthanum, amount of phosfate, pH and duration time were optimized. The % recoveries of the analyte ion were in the range of 95-105 % with limit of detection (3s) of 0.5 µg l-1. Preconcentration factor was found as 1000 and Relative Standard Deviation (RSD) % value obtained from model solutions was 2...
2017: Iranian Journal of Pharmaceutical Research: IJPR
Zack Geballe, Hanyu Liu, Ajay K Mishra, Muhtar Ahart, Maddury Somayazulu, Yue Meng, Maria Baldini, Russell J Hemley
Recent theoretical calculations predict that megabar pressure stabilizes very hydrogen-rich simple compounds having new clathrate-like structures and remarkable electronic properties including room-temperature superconductivity. We report x-ray diffraction and optical studies demonstrating that superhydrides of lanthanum can be synthesized with La atoms in an fcc lattice at 170 GPa upon heating to ~1000 K. The results match the predicted cubic metallic phase of LaH10 having cages of thirty-two hydrogen atoms surrounding each La atom...
November 29, 2017: Angewandte Chemie
Francesco Giannici, Giovanna Canu, Alessandro Chiara, Marianna Gambino, Chiara Aliotta, Alessandro Longo, Vincenzo Buscaglia, Antonino Martorana
The chemical compatibility between electrolytes and electrodes is an extremely important aspect governing the overall impedance of solid-oxide cells. Since these devices work at elevated temperatures, they are especially prone to cation interdiffusion between the cell components, possibly resulting in secondary insulating phases. In this work, we applied X-ray microspectroscopy to study the interface between a samarium-doped ceria electrolyte and lanthanum ferrite cathodes (La0.9Sr0.1Fe0.85Cu0.15O3 - LSCF; La0...
December 1, 2017: ACS Applied Materials & Interfaces
Takuya Okugawa, Kaoru Ohno, Yusuke Noda, Shinichiro Nakamura
We investigate spin-dependent electronic states of antiferromagnetic (AFM) lanthanum chromite (LaCrO<sub>3</sub>), lanthanum manganite (LaMnO<sub>3</sub>), and lanthanum ferrite (LaFeO<sub>3</sub>) using spin-polarized first-principles density functional theory (DFT) with Hubbard <i>U</i> correction. The band structures are calculated for 15 types of their different AFM structures. It is verified for these structures that there is a very simple rule to identify which wave number <b><i>k</i></b> exhibits spin splitting or degeneracy in the band structure...
November 30, 2017: Journal of Physics. Condensed Matter: An Institute of Physics Journal
Julia V Zaikina, Van S Griffin, Susan E Latturner
Reactions of tin and manganese in a lanthanum/nickel eutectic melt in alumina crucibles produce La11Mn13-x-yNixAlySn4-δ (0 ≤ x ≤ 3.6; 2.5 ≤ y ≤ 4.9; 0.6 ≤ δ ≤ 1.1) phases with the stoichiometry dependent on the reactant ratio. These compounds crystallize in a new tetragonal structure type in space group P4/mbm, with a = 8.4197(1) Å, c = 19.2414(3) Å, and Z = 2 for La11Mn8.2Ni0.8Al4Sn3.3. The structure can be viewed as an intergrowth between La6Co11Ga3-type layers and Cr5B3-type La/Sn slabs. This system represents a unique playground to study the itinerant magnetism of diluted icosahedral Mn layers...
November 28, 2017: Inorganic Chemistry
Santosh K Suram, Sean Fackler, Lan Zhou, Alpha T N'Diaye, Walter S Drisdell, Junko Yano, John M Gregoire
Oxynitrides with the photoelectrochemical stability of oxides and desirable band energetics of nitrides comprise a promising class of materials for solar photochemistry. Challenges in synthesizing a wide variety of oxynitride materials has limited exploration of this class of functional materials, which we address using a reactive co-sputtering combined with rapid thermal processing method to synthesize multi-cation-multi-anion libraries. We demonstrate the synthesis of a LaxTa1-xOyNz thin film composition spread library and its characterization by both traditional thin film materials characterization and custom combinatorial optical spectroscopy and X-ray Absorption Near Edge Spectroscopy (XANES) techniques, ultimately establishing structure-chemistry-property relationships...
November 27, 2017: ACS Combinatorial Science
Dajiang Liu, Kwang Ho Kim, Jian Sun, Blake Simmons, Seema Singh
Lignocellulosic biomass conversion to value-added platform chemicals in the non-toxic, water-tolerant Lewis acid, and water solutions bears the hallmark of green chemistry. Lactic acid derived from biomass is an important chemical building block for biodegradable polymers such as polylactide. Herein, a universal method of converting lignocellulosic sugars to lactic acid using catalytic amount of water-stable Lewis acid La(OTf)3 is demonstrated. The lignocellulosic sugars studied in this work include 1) pyrolytic sugars from pyrolysis oil, and 2) sugars derived from ionic liquid (IL)-pretreated biomass...
November 27, 2017: ChemSusChem
Michael A Boreen, Bernard F Parker, Stephan Hohloch, Brighton A Skeel, John Arnold
Straightforward syntheses are provided for the m-terphenyl dithiocarboxylic acid 2,6-(C6H4-4-tBu)2C6H3CS2H (TerphCS2H, 2) and its lithium and potassium salts, TerphCS2Li(Et2O)2 and TerphCS2K (1·Et2O and 4, respectively). These compounds can be isolated in good yields on multi-gram scales starting from Terph-I without isolating intermediates. Salt metathesis and protonolysis reactions provided access to the homoleptic actinide(iv) complexes (TerphCS2)4An (An = Th (5) and U (6)). Electrochemical and reactivity studies revealed that the dithiocarboxylate ligand is incompatible with U(iii)...
November 27, 2017: Dalton Transactions: An International Journal of Inorganic Chemistry
M A de León-Alfaro, A Morales-Hernández, J Roman-Lopez, J Zarate-Medina, T Rivera-Montalvo
This paper reports on an investigation into the thermally stimulated luminescence (TL) and optically stimulated luminescence (OSL) characteristics of novel luminescent phosphor. A new Pr(3+)-doped, lanthanum aluminate (LaAlO3)-based luminescent phosphor is developed. Samples of LaAlO3:Pr(3+) were irradiated to beta doses, in air, from 0.1Gy up to 50Gy and then were analyzed using both TL and continuous wavelength OSL (CW-OSL) techniques to determine their luminescent characteristics. This phosphor shows a TL glow curve, after its irradiation to beta radiation, with two TL peaks: one located around 160°C and a second at 300°C...
November 14, 2017: Applied Radiation and Isotopes
Jinxia Li, Rudo A Verweij, Cornelis A M van Gestel
This study determined the toxicity of lanthanum, one of the most commonly used rare earth elements (REEs), to five representative soil invertebrates after 3-4 weeks exposure. Toxicity was related to total, 0.01 M CaCl2-extractable and porewater concentrations in the standard LUFA 2.2 soil, and for earthworms also to body concentrations. La sorption to LUFA 2.2 soil, estimated by relating total soil concentrations to CaCl2-extractable or porewater concentrations seemed to reach saturation at >1000 mg La/kg dry soil...
November 10, 2017: Chemosphere
Atsuya Koizumi, Takuya Hasegawa, Atsushi Itadani, Kenji Toda, Taoyun Zhu, Mineo Sato
In the title complex, di-aqua-(1H-imidazole-κN(3))(nitrato-κ(2)O,O')bis-(4-oxo-pent-2-en-2-olato-κ(2)O,O')lanthanum(III), [La(C5H7O2)2(NO3)(C3H4N2)(H2O)2], the La atom is coordinated by eight O atoms of two acetyl-acetonate (acac) anions acting as bidentate ligands, two water mol-ecule as monodentate ligands, one nitrate anions as a bidentate ligand and one N atom of an imidazolate (ImH) molecule as a monodentate ligand. Thus, the coordination number of the La atom is nine in a monocapped square anti-prismatic polyhedron...
November 1, 2017: Acta Crystallographica. Section E, Crystallographic Communications
Chunhua Zhang, Shixiang Wang, Sumei Zhao, Xiaodong Zhang
BACKGROUND: The incidence of adynamic bone disease (ABD) is increasing. Coronary artery calcification (CAC) may be severe in patients with ABD on maintenance hemodialysis (MHD). The aim of this study was to evaluate the effect of lanthanum carbonate (LC) on CAC and bone mineral density (BMD) in MHD patients with diabetes complicated with ABD. METHODS: A total of 92 MHD cases were divided into the calcium carbonate (CC) and LC groups. Primary outcome measure was the changes in the degree of CAC score (CACS) and BMD in forearm from baseline to 12 months...
November 2017: Medicine (Baltimore)
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