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https://www.readbyqxmd.com/read/28340456/macroscopic-and-microscopic-investigation-of-adsorption-and-precipitation-of-zn-on-%C3%AE-alumina-in-the-absence-and-presence-of-as
#1
Yu-Jun Wang, Ting-Ting Fan, Cun Liu, Wei Li, Meng-Qiang Zhu, Jian-Xin Fan, Hua Gong, Dong-Mei Zhou, Donald L Sparks
Contaminants zinc (Zn) and arsenate (As) often coexist in soils. However, little is known concerning the impacts of coexisting As on Zn adsorption and precipitation on soil minerals. In the present study, adsorption and precipitation of Zn on γ-alumina in the absence and presence of arsenate was investigated employing batch experiments and Extended X-ray Absorption Fine Structure (EXAFS) spectroscopy. Results indicated that Zn formed edge-sharing tetrahedral surface complexes at pH 5.5 and Zn-Al LDH-like (layered double hydroxide) precipitates at pH 7...
March 21, 2017: Chemosphere
https://www.readbyqxmd.com/read/28338312/engineering-nanoscale-iron-oxides-for-uranyl-sorption-and-separation-optimization-of-particle-core-size-and-bilayer-surface-coatings
#2
Wenlu Li, Lyndsay D Troyer, Seung Soo Lee, Jiewei Wu, Changwoo Kim, Brandon J Lafferty, Jeffrey G Catalano, John D Fortner
Herein, we describe engineered superparamagnetic iron oxide nanoparticles (IONPs) as platform materials for enhanced uranyl (UO22+) sorption and separation processes under environmentally relevant conditions. Specifically, monodispersed 8-25 nm iron oxide (magnetite, Fe3O4) nanoparticles with tailored organic acid bilayered coatings have been systematically evaluated and optimized to bind, and thus remove, uranium, from water. The combined non-hydrolytic synthesis and bilayer phase transfer material preparation methods yield highly uniform and surface tailorable IONPs, which allow us to directly evaluate the size-dependent and coating-dependent sorption capacities of IONPs...
March 24, 2017: ACS Applied Materials & Interfaces
https://www.readbyqxmd.com/read/28338264/engineering-high-energy-interfacial-structures-for-high-performance-oxygen-involving-electrocatalysis
#3
Chunxian Guo, Yao Zheng, Jingrun Ran, Fangxi Xie, Mietek Jaroniec, Shi-Zhang Qiao
Engineering high-energy interfacial structures for high-performance electrocatalysis is achieved by chemical coupling of active CoO nanoclusters and high-index facet Mn3 O4 nano-octahedrons (hi-Mn3 O4 ). A thorough characterization, including synchrotron-based near edge X-ray absorption fine structure, reveals that strong interactions between both components promote the formation of high-energy interfacial Mn-O-Co species and high oxidation state CoO, from which electrons are drawn by Mn(III) -O present in hi-Mn3 O4 ...
March 24, 2017: Angewandte Chemie
https://www.readbyqxmd.com/read/28337116/assessment-of-usefulness-of-synchrotron-radiation-techniques-to-determine-arsenic-species-in-hair-and-rice-grain-samples
#4
Jun Lin, Guo-Fang Lin, Yu-Lan Li, Xiao-Yan Gao, Hui Du, Chao-Gang Jia, Hong-Chao Lu, Klaus Golka, Jian-Hua Shen
The arseniasis in Southwest Guizhou, China has been identified as a unique case of endemic arseniasis caused by exposure to indoor combustion of high As-content coal. Present investigation targeted the microdistribution and speciation of the element arsenic in human hair and environmental samples collected in one of the hyper-endemic villages of arseniasis in the area. Analyses were performed by micro-beam X-ray fluorescence (μ-XRF) and X-ray absorption fine structure (XAFS). The total As level in hair samples of diagnosed patients was detected at almost the same level as in their asymptomatic neighbors...
2017: EXCLI journal
https://www.readbyqxmd.com/read/28336935/preservation-of-organic-matter-in-marine-sediments-by-inner-sphere-interactions-with-reactive-iron
#5
Andrew Barber, Jay Brandes, Alessandra Leri, Karine Lalonde, Kathryn Balind, Sue Wirick, Jian Wang, Yves Gélinas
Interactions between organic matter and mineral matrices are critical to the preservation of soil and sediment organic matter. In addition to clay minerals, Fe(III) oxides particles have recently been shown to be responsible for the protection and burial of a large fraction of sedimentary organic carbon (OC). Through a combination of synchrotron X-ray techniques and high-resolution images of intact sediment particles, we assessed the mechanism of interaction between OC and iron, as well as the composition of organic matter co-localized with ferric iron...
March 23, 2017: Scientific Reports
https://www.readbyqxmd.com/read/28335367/investigating-polymer-metal-interfaces-by-grazing-incidence-small-angle-x-ray-scattering-from-gradients-to-real-time-studies
#6
REVIEW
Matthias Schwartzkopf, Stephan V Roth
Tailoring the polymer-metal interface is crucial for advanced material design. Vacuum deposition methods for metal layer coating are widely used in industry and research. They allow for installing a variety of nanostructures, often making use of the selective interaction of the metal atoms with the underlying polymer thin film. The polymer thin film may eventually be nanostructured, too, in order to create a hierarchy in length scales. Grazing incidence X-ray scattering is an advanced method to characterize and investigate polymer-metal interfaces...
December 10, 2016: Nanomaterials
https://www.readbyqxmd.com/read/28334658/extraction-of-the-3d-local-orientation-of-myocytes-in-human-cardiac-tissue-using-x-ray-phase-contrast-micro-tomography-and-multi-scale-analysis
#7
François Varray, Iulia Mirea, Max Langer, Françoise Peyrin, Laurent Fanton, Isabelle E Magnin
This paper presents a methodology to access the 3D local myocyte arrangements in fresh human post-mortem heart samples. We investigated the cardiac micro-structure at a high and isotropic resolution of 3.5 µm in three dimensions using X-ray phase micro-tomography at the European Synchrotron Radiation Facility. We then processed the reconstructed volumes to extract the 3D local orientation of the myocytes using a multi-scale approach with no segmentation. We created a simplified 3D model of tissue sample made of simulated myocytes with known size and orientations, to evaluate our orientation extraction method...
February 20, 2017: Medical Image Analysis
https://www.readbyqxmd.com/read/28333689/computational-modelling-of-the-cerebral-cortical-microvasculature-effect-of-x-ray-microbeams-versus-broad-beam-irradiation
#8
Andreas Merrem, Stefan Bartzsch, Jean Laissue, Uwe Oelfke
Microbeam Radiation Therapy is an innovative pre-clinical strategy which uses arrays of parallel, tens of micrometre wide kilo-voltage photon beams to treat tumours. These X-ray beams are typically generated on a synchrotron source. It was shown that these beam geometries allow exceptional normal tissue sparing from radiation damage while still being effective in tumour ablation. A final biological explanation for this enhanced therapeutic ratio has still not been found, some experimental data support an important role of the vasculature...
March 23, 2017: Physics in Medicine and Biology
https://www.readbyqxmd.com/read/28332675/tailoring-the-structure-and-thermoelectric-properties-of-batio3via-eu-2-substitution
#9
Xingxing Xiao, Marc Widenmeyer, Wenjie Xie, Tianhua Zou, Songhak Yoon, Marco Scavini, Stefano Checchia, Zhicheng Zhong, Philipp Hansmann, Stefan Kilper, Andrei Kovalevsky, Anke Weidenkaff
A series of Ba1-xEuxTiO3-δ (0.1 ≤ x ≤ 0.9) phases with ∼40 nm particle size were synthesized via a Pechini method followed by annealing and sintering under a reducing atmosphere. The effects of Eu(2+) substitution on the BaTiO3 crystal structure and the thermoelectric transport properties were systematically investigated. According to synchrotron X-ray diffraction data only cubic perovskite structures were observed. On the local scale below about 20 Å (equal to ∼5 unit cells) deviations from the cubic structure model (Pm3[combining macron]m) were detected by evaluation of the pair distribution function (PDF)...
March 23, 2017: Physical Chemistry Chemical Physics: PCCP
https://www.readbyqxmd.com/read/28332562/new-insights-on-the-biomineralisation-process-developing-in-human-lungs-around-inhaled-asbestos-fibres
#10
Fabrizio Bardelli, Giulia Veronesi, Silvana Capella, Donata Bellis, Laurent Charlet, Alessia Cedola, Elena Belluso
Once penetrated into the lungs of exposed people, asbestos induces an in vivo biomineralisation process that leads to the formation of a ferruginous coating embedding the fibres. The ensemble of the fibre and the coating is referred to as asbestos body and is believed to be responsible for the high toxicological outcome of asbestos. Lung tissue of two individuals subjected to prolonged occupational exposure to crocidolite asbestos was investigated using synchrotron radiation micro-probe tools. The distribution of K and of elements heavier than Fe (Zn, Cu, As, and Ba) in the asbestos bodies was observed for the first time...
March 23, 2017: Scientific Reports
https://www.readbyqxmd.com/read/28332093/pathogenic-implications-of-distinct-patterns-of-iron-and-zinc-in-chronic-ms-lesions
#11
Bogdan F Popescu, Josa M Frischer, Samuel M Webb, Mylyne Tham, Reginald C Adiele, Christopher A Robinson, Patrick D Fitz-Gibbon, Stephen D Weigand, Imke Metz, Susan Nehzati, Graham N George, Ingrid J Pickering, Wolfgang Brück, Simon Hametner, Hans Lassmann, Joseph E Parisi, Guo Yong, Claudia F Lucchinetti
Multiple sclerosis (MS) is a chronic inflammatory demyelinating disease of the central nervous system (CNS) in which oligodendrocytes, the CNS cells that stain most robustly for iron and myelin are the targets of injury. Metals are essential for normal CNS functioning, and metal imbalances have been linked to demyelination and neurodegeneration. Using a multidisciplinary approach involving synchrotron techniques, iron histochemistry and immunohistochemistry, we compared the distribution and quantification of iron and zinc in MS lesions to the surrounding normal appearing and periplaque white matter, and assessed the involvement of these metals in MS lesion pathogenesis...
March 22, 2017: Acta Neuropathologica
https://www.readbyqxmd.com/read/28329054/whole-heart-detailed-and-quantitative-anatomy-myofibre-structure-and-vasculature-from-x-ray-phase-contrast-synchrotron-radiation-based-micro-computed-tomography
#12
Anna Gonzalez-Tendero, Chong Zhang, Vedrana Balicevic, Rubén Cárdenes, Sven Loncaric, Constantine Butakoff, Bruno Paun, Anne Bonnin, Patricia Garcia-Cañadilla, Emma Muñoz-Moreno, Eduard Gratacós, Fatima Crispi, Bart Bijnens
Background: While individual cardiac myocytes only have a limited ability to shorten, the heart efficiently pumps a large volume-fraction thanks to a cell organization in a complex 3D fibre structure. Subclinical subtle cardiac structural remodelling is often present before symptoms arise. Understanding and early detection of these subtle changes is crucial for diagnosis and prevention. Additionally, personalized computational modelling requires knowledge on the multi-scale structure of the whole heart and vessels...
March 15, 2017: European Heart Journal Cardiovascular Imaging
https://www.readbyqxmd.com/read/28328229/characterization-of-the-bonds-developed-between-calcium-silicate-hydrate-and-polycarboxylate-based-superplasticizers-with-silyl-functionalities
#13
Carlos A Orozco, Byong-Wa Zen Chun, Guoqing Geng, Abdul-Hamid Emwas, Paulo J M Monteiro
Major developments in concrete technology have been achieved with the use of polycarboxylate-based superplasticizers (PCEs) to improve the concrete rheology without increasing the mix water content. Currently, it is possible to control the fluidity of the fresh concrete and obtain stronger and more durable structures. Therefore, there is a strong incentive to understand the interactions between PCEs and cement hydrates at the atomic scale to design new customized functional PCEs according to the ever-increasing requirements of the concrete industry...
March 22, 2017: Langmuir: the ACS Journal of Surfaces and Colloids
https://www.readbyqxmd.com/read/28328028/large-area-elemental-imaging-reveals-van-eyck-s-original-paint-layers-on-the-ghent-altarpiece-1432-rescoping-its-conservation-treatment
#14
Geert Van der Snickt, Hélène Dubois, Jana Sanyova, Stijn Legrand, Alexia Coudray, Cécile Glaude, Marie Postec, Piet Van Espen, Koen Janssens
A combination of large-scale and micro-scale elemental imaging, yielding elemental distribution maps obtained by, respectively non-invasive macroscopic X-ray fluorescence (MA-XRF) and by secondary electron microscopy/energy dispersive X-ray analysis (SEM-EDX) and synchrotron radiation-based micro-XRF (SR μ-XRF) imaging was employed to reorient and optimize the conservation strategy of van Eyck's renowned Ghent Altarpiece. By exploiting the penetrative properties of X-rays together with the elemental specificity offered by XRF, it was possible to visualize the original paint layers by van Eyck hidden below the overpainted surface and to simultaneously assess their condition...
March 22, 2017: Angewandte Chemie
https://www.readbyqxmd.com/read/28325307/effects-of-coagulation-conditions-on-structure-and-properties-of-cellulose-based-fibers-from-aqueous-naoh-solvent
#15
Wencong Wang, Faxue Li, Jianyong Yu, Jian Zhou, Hongbo Wang
Hydroxyethyl cellulose (HEC) fibers with low degree of substitution were prepared by wet spinning of solutions in 8wt% NaOH solvent, and H2SO4/Na2SO4/ZnSO4 solution was chosen as coagulants. The influence of coagulation temperature and H2SO4 concentration on structure and mechanical properties of resultant HEC fibers was examined by synchrotron X-ray measurements, scanning electron microscope and tensile tests. The results were analyzed from the perspective of coagulation kinetics by determining coagulation rate and mass transfer rate difference...
May 15, 2017: Carbohydrate Polymers
https://www.readbyqxmd.com/read/28323518/synthesis-crystallization-and-preliminary-crystallographic-analysis-of-a-52-nucleotide-dna-2-ome-rna-oligomer-mimicking-10-23-dnazyme-in-the-complex-with-a-substrate
#16
Rafał Dolot, Milena Sobczak, Barbara Mikołajczyk, Barbara Nawrot
A 52-nucleotide DNA/2'-OMe-RNA oligomer mimicking 10-23 DNAzyme in the complex with its substrate was synthesized, purified and crystallized by the hanging-drop method using 0.8 M sodium potassium tartrate as a precipitant. A data set to 1.21 Å resolution was collected from a monocrystal at 100 K using synchrotron radiation on a beamline BL14.1 at BESSY. The crystal belonged to the P21 group with unit-cell a = 49.42, b = 24.69, c = 50.23, β = 118.48.
March 21, 2017: Nucleosides, Nucleotides & Nucleic Acids
https://www.readbyqxmd.com/read/28323401/zinc-and-copper-effects-on-stability-of-tubulin-and-actin-networks-in-dendrites-and-spines-of-hippocampal-neurons
#17
Laura Perrin, Stephane Roudeau, Asuncion Carmona, Florelle Domart, Jennifer D Petersen, Sylvain Bohic, Yang Yang, Peter Cloetens, Richard Ortega
Zinc and copper ions can modulate the activity of glutamate-receptors. However, labile zinc and copper ions likely represent only the tip of the iceberg and other neuronal functions are suspected for these metals in their bound state. We performed synchrotron X-ray fluorescence imaging with 30 nm resolution to image total biometals in dendrites and spines from hippocampal neurons. We found that zinc is distributed all along the dendrites while copper is mainly pinpointed within the spines. In spines, zinc content is higher within the spine head while copper is higher within the spine neck...
March 21, 2017: ACS Chemical Neuroscience
https://www.readbyqxmd.com/read/28322316/grid-enhanced-x-ray-coded-aperture-microscopy-with-polycapillary-optics
#18
Katarzyna M Sowa, Arndt Last, Paweł Korecki
Polycapillary devices focus X-rays by means of multiple reflections of X-rays in arrays of bent glass capillaries. The size of the focal spot (typically 10-100 μm) limits the resolution of scanning, absorption and phase-contrast X-ray imaging using these devices. At the expense of a moderate resolution, polycapillary elements provide high intensity and are frequently used for X-ray micro-imaging with both synchrotrons and X-ray tubes. Recent studies have shown that the internal microstructure of such an optics can be used as a coded aperture that encodes high-resolution information about objects located inside the focal spot...
March 21, 2017: Scientific Reports
https://www.readbyqxmd.com/read/28316819/crystal-structure-of-bis-oxalato-%C3%AE%C2%BA-2-o-1-o-2-1-4-8-11-tetra-aza-cyclo-tetra-decane-%C3%AE%C2%BA-4-n-chromium-iii-dichromate-octa-hydrate-from-synchrotron-x-ray-data
#19
Dohyun Moon, Jong-Ha Choi
The asymmetric unit of the title compound, [Cr(C2O4)(C10H24N4)]2[Cr2O7]·8H2O (C10H24N4 = 1,4,8,11-tetra-aza-cyclo-tetra-decane, cyclam; C2O4 = oxalate, ox) contains one [Cr(ox)(cyclam)](+) cation, one half of a dichromate anion that lies about an inversion centre so that the bridging O atom is equally disordered over two positions, and four water mol-ecules. The terminal O atoms of the dichromate anion are also disordered over two positions with a refined occupancy ratio 0.586 (6):0.414 (6). The Cr(III) ion is coordinated by the four N atoms of the cyclam ligand and one bidentate oxalato ligand in a cis arrangement, resulting in a distorted octa-hedral geometry...
March 1, 2017: Acta Crystallographica. Section E, Crystallographic Communications
https://www.readbyqxmd.com/read/28316816/crystal-structure-of-9-20-dimethyl-1-8-12-19-tetra-aza-tetra-cyclo-17-3-1-0-2-7-0-13-18-tricosane-dihydrate-from-synchrotron-x-ray-data
#20
Dohyun Moon, Jong-Ha Choi
The structure of the title compound, C21H40N4·2H2O, has been determined from synchrotron X-ray radiation data. The asymmetric unit comprises one 12-membered macropolycycle and two lattice water mol-ecules. The macropolycycle contains two cyclo-hexane rings and one 1,3-di-aza-cyclo-hexane ring, all in chair conformations. The C-N and C-C bond lengths are in the ranges 1.4526 (16)-1.4786 (17) and 1.517 (2)-1.5414 (17) Å, respectively. One intra-molecular N-H⋯N hydrogen bond helps to stabilize the mol-ecular conformation while medium-strength inter-molecular N-H⋯O, O-H⋯N and O-H⋯O hydrogen bonds involving the lattice water mol-ecules connect the components into a three-dimensional network...
March 1, 2017: Acta Crystallographica. Section E, Crystallographic Communications
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