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https://www.readbyqxmd.com/read/27910840/-na-%C3%A2-5-mno2-13-nanorods-a-new-tunnel-structure-for-electrode-materials-determined-ab-initio-and-refined-through-a-combination-of-electron-and-synchrotron-diffraction-data
#1
Enrico Mugnaioli, Mauro Gemmi, Marco Merlini, Michele Gregorkiewitz
(Nax□1 - x)5[MnO2]13 has been synthesized with x = 0.80 (4), corresponding to Na0.31[MnO2]. This well known material is usually cited as Na0.4[MnO2] and is believed to have a romanèchite-like framework. Here, its true structure is determined, ab initio, by single-crystal electron diffraction tomography (EDT) and refined both by EDT data applying dynamical scattering theory and by the Rietveld method based on synchrotron powder diffraction data (χ(2) = 0.690, Rwp = 0.051, Rp = 0.037, RF2 = 0.035). The unit cell is monoclinic C2/m, a = 22...
December 1, 2016: Acta Crystallographica Section B, Structural Science, Crystal Engineering and Materials
https://www.readbyqxmd.com/read/27910835/two-cubic-phases-in-kimzeyite-garnet-from-the-type-locality-magnet-cove-arkansas
#2
Sytle M Antao, Laura A Cruickshank
The crystal structure of an optically anisotropic kimzeyite garnet from Magnet Cove, Arkansas, USA, where it was first discovered, was refined with the Rietveld method, cubic space group, Ia\overline 3 d, and monochromatic [λ = 0.41422 (2) Å] synchrotron high-resolution powder X-ray diffraction (HRPXRD) data. The Rietveld refinement reduced χ(2) and overall R(F(2)) values are 1.840 and 0.0647, respectively. The sample, with the general garnet formula ([8])X3([6])Y2([4])Z3([4])O12, contains an intergrowth of two cubic phases that occur initially as oscillatory growth zoning, and patchy intergrowths arise later from fluid-enhanced dissolution and re-precipitation...
December 1, 2016: Acta Crystallographica Section B, Structural Science, Crystal Engineering and Materials
https://www.readbyqxmd.com/read/27910692/observation-of-runaway-electrons-by-infrared-camera-in-j-text
#3
R H Tong, Z Y Chen, M Zhang, D W Huang, W Yan, G Zhuang
When the energy of confined runaway electrons approaches several tens of MeV, the runaway electrons can emit synchrotron radiation in the range of infrared wavelength. An infrared camera working in the wavelength of 3-5 μm has been developed to study the runaway electrons in the Joint Texas Experimental Tokamak (J-TEXT). The camera is located in the equatorial plane looking tangentially into the direction of electron approach. The runaway electron beam inside the plasma has been observed at the flattop phase...
November 2016: Review of Scientific Instruments
https://www.readbyqxmd.com/read/27910601/combined-scanning-probe-microscopy-and-x-ray-scattering-instrument-for-in-situ-catalysis-investigations
#4
Willem G Onderwaater, Peter C van der Tuijn, Rik V Mom, Matthijs A van Spronsen, Sander B Roobol, Amirmehdi Saedi, Jakub Drnec, Helena Isern, Francesco Carla, Thomas Dufrane, Raymond Koehler, Bert Crama, Irene M N Groot, Roberto Felici, Joost W M Frenken
We have developed a new instrument combining a scanning probe microscope (SPM) and an X-ray scattering platform for ambient-pressure catalysis studies. The two instruments are integrated with a flow reactor and an ultra-high vacuum system that can be mounted easily on the diffractometer at a synchrotron end station. This makes it possible to perform SPM and X-ray scattering experiments in the same instrument under identical conditions that are relevant for catalysis.
November 2016: Review of Scientific Instruments
https://www.readbyqxmd.com/read/27910568/mobile-setup-for-synchrotron-based-in-situ-characterization-during-thermal-and-plasma-enhanced-atomic-layer-deposition
#5
Jolien Dendooven, Eduardo Solano, Matthias M Minjauw, Kevin Van de Kerckhove, Alessandro Coati, Emiliano Fonda, Giuseppe Portale, Yves Garreau, Christophe Detavernier
We report the design of a mobile setup for synchrotron based in situ studies during atomic layer processing. The system was designed to facilitate in situ grazing incidence small angle x-ray scattering (GISAXS), x-ray fluorescence (XRF), and x-ray absorption spectroscopy measurements at synchrotron facilities. The setup consists of a compact high vacuum pump-type reactor for atomic layer deposition (ALD). The presence of a remote radio frequency plasma source enables in situ experiments during both thermal as well as plasma-enhanced ALD...
November 2016: Review of Scientific Instruments
https://www.readbyqxmd.com/read/27910538/a-compact-and-versatile-dynamic-flow-cryostat-for-photon-science
#6
Peter J E M van der Linden, Marco Moretti Sala, Christian Henriquet, Matteo Rossi, Kenya Ohgushi, François Fauth, Laura Simonelli, Carlo Marini, Edmundo Fraga, Claire Murray, Jonathan Potter, Michael Krisch
We have developed a helium gas flow cryostat for use on synchrotron tender to hard X-ray beamlines. Very efficient sample cooling is achieved because the sample is placed directly in the cooling helium flow on a removable sample holder. The cryostat is compact and easy to operate; samples can be changed in less than 5 min at any temperature. The cryostat has a temperature range of 2.5-325 K with temperature stability better than 0.1 K. The very wide optical angle and the ability to operate in any orientation mean that the cryostat can easily be adapted for different X-ray techniques...
November 2016: Review of Scientific Instruments
https://www.readbyqxmd.com/read/27908159/a-preclinical-microbeam-facility-with-a-conventional-x-ray-tube
#7
Stefan Bartzsch, Craig Cummings, Stephan Eismann, Uwe Oelfke
PURPOSE: Microbeam radiation therapy is an innovative treatment approach in radiation therapy that uses arrays of a few tens of micrometer wide and a few hundreds of micrometer spaced planar x-ray beams as treatment fields. In preclinical studies these fields efficiently eradicated tumors while normal tissue could effectively be spared. However, development and clinical application of microbeam radiation therapy is impeded by a lack of suitable small scale sources. Until now, only large synchrotrons provide appropriate beam properties for the production of microbeams...
December 2016: Medical Physics
https://www.readbyqxmd.com/read/27908128/identifying-barriers-to-charge-carriers-in-the-bulk-and-surface-regions-of-cu2znsns4-nanocrystal-films-by-x-ray-absorption-fine-structures-xafss
#8
Matthew J Turnbull, Daniel Vaccarello, Yun Mui Yiu, Tsun-Kong Sham, Zhifeng Ding
Solar cell performance is most affected by the quality of the light absorber layer. For thin-film devices, this becomes a two-fold problem of maintaining a low-cost design with well-ordered nanocrystal (NC) structure. The use of Cu2ZnSnS4 (CZTS) NCs as the light absorber films forms an ideal low-cost design, but the quaternary structure makes it difficult to maintain a well-ordered layer without the use of high-temperature treatments. There is little understanding of how CZTS NC structures affect the photoconversion efficiency, the charge-carriers, and therefore the performance of the device manufactured from it...
November 28, 2016: Journal of Chemical Physics
https://www.readbyqxmd.com/read/27906408/spatially-uniform-resistance-switching-of-low-current-high-endurance-titanium-niobium-oxide-memristors
#9
Suhas Kumar, Noraica Davila, Ziwen Wang, Xiaopeng Huang, John Paul Strachan, David Vine, A L David Kilcoyne, Yoshio Nishi, R Stanley Williams
We analyzed micrometer-scale titanium-niobium-oxide prototype memristors, which exhibited low write-power (<3 μW) and energy (<200 fJ per bit per μm(2)), low read-power (∼nW), and high endurance (>millions of cycles). To understand their physico-chemical operating mechanisms, we performed in operando synchrotron X-ray transmission nanoscale spectromicroscopy using an ultra-sensitive time-multiplexed technique. We observed only spatially uniform material changes during cell operation, in sharp contrast to the frequently detected formation of a localized conduction channel in transition-metal-oxide memristors...
December 1, 2016: Nanoscale
https://www.readbyqxmd.com/read/27906228/holographic-imaging-with-a-hard-x-ray-nanoprobe-ptychographic-versus-conventional-phase-retrieval
#10
A-L Robisch, J Wallentin, A Pacureanu, P Cloetens, T Salditt
We have performed near-field x-ray imaging with simultaneous object and probe reconstruction. By an advanced ptychographic algorithm based on longitudinal and lateral translations, full-field images of nanoscale objects are reconstructed with quantitative contrast values, along with the extended wavefronts used to illuminate the objects. The imaging scheme makes idealizing assumptions on the probe obsolete, and efficiently disentangles phase shifts related to the object from the imperfections in the illumination...
December 1, 2016: Optics Letters
https://www.readbyqxmd.com/read/27904078/effect-of-nerolidol-and-or-levulinic-acid-on-the-thermotropic-behavior-of-lipid-lamellar-structures-in-the-stratum-corneum
#11
Shunichi Utsumi, Tomohiro Nakamura, Yasuko Obata, Noboru Ohta, Kozo Takayama
Permeation enhancers are required to deliver drugs through the skin efficiently and maintain effective blood concentrations. Studies of the barrier function of the stratum corneum using l-menthol, a monocyclic monoterpene widely used in medicines and foods, have revealed an interaction between characteristic intercellular lipid structures in the stratum corneum and permeation enhancers. The variety of permeation enhancers that can be used to contribute to transdermal delivery systems beyond l-menthol is increasing...
2016: Chemical & Pharmaceutical Bulletin
https://www.readbyqxmd.com/read/27900454/intact-imaging-of-human-heart-structure-using-x-ray-phase-contrast-tomography
#12
Yukihiro Kaneko, Gen Shinohara, Masato Hoshino, Hiroyuki Morishita, Kiyozo Morita, Yoshihiro Oshima, Masashi Takahashi, Naoto Yagi, Yutaka Okita, Takuro Tsukube
Structural examination of human heart specimens at the microscopic level is a prerequisite for understanding congenital heart diseases. It is desirable not to destroy or alter the properties of such specimens because of their scarcity. However, many of the currently available imaging techniques either destroy the specimen through sectioning or alter the chemical and mechanical properties of the specimen through staining and contrast agent injection. As a result, subsequent studies may not be possible. X-ray phase-contrast tomography is an imaging modality for biological soft tissues that does not destroy or alter the properties of the specimen...
November 30, 2016: Pediatric Cardiology
https://www.readbyqxmd.com/read/27898777/synchrotron-based-x-ray-spectroscopy-studies-for-redox-based-remediation-of-lead-zinc-and-cadmium-in-mine-waste-materials
#13
Ranju R Karna, Ganga M Hettiarachchi, Matthew Newville, ChengJun Sun, Qing Ma
Several studies have examined the effect of submergence on the mobility of metals present in mine waste materials. This study examines the effect of organic carbon (OC) and sulfur (S) additions and submergence time on redox-induced biogeochemical transformations of lead (Pb), zinc (Zn), and cadmium (Cd) present in mine waste materials collected from the Tri-State mining district located in southeastern Kansas, southwestern Missouri, and northeastern Oklahoma. A completely randomized design, with a two-way treatment structure, was used for conducting a series of column experiments...
November 2016: Journal of Environmental Quality
https://www.readbyqxmd.com/read/27897249/visualization-and-pathological-characteristics-of-hepatic-alveolar-echinococcosis-with-synchrotron-based-x-ray-phase-sensitive-micro-tomography
#14
Huiqiang Liu, Xuewen Ji, Li Sun, Tiqiao Xiao, Honglan Xie, Yanan Fu, Yuan Zhao, Wenya Liu, Xueliang Zhang, Renyong Lin
Propagation-based phase-contrast computed tomography (PPCT) utilizes highly sensitive phase-contrast technology applied to X-ray micro-tomography, especially with the extensive use of synchrotron radiation (SR). Performing phase retrieval (PR) on the acquired angular projections can enhance image contrast and enable quantitative imaging. We employed the combination of SR-PPCT and PR for the histopathological evaluation of hepatic alveolar echinococcosis (HAE) disease and demonstrated the validity and superiority of PR-based SR-PPCT...
November 29, 2016: Scientific Reports
https://www.readbyqxmd.com/read/27896717/a-practical-approach-to-protein-crystallography
#15
Andrea Ilari, Carmelinda Savino
Macromolecular crystallography is a powerful tool for structural biology. The resolution of a protein crystal structure is becoming much easier than in the past, thanks to developments in computing, automation of crystallization techniques and high-flux synchrotron sources to collect diffraction datasets. The aim of this chapter is to provide practical procedures to determine a protein crystal structure, illustrating the new techniques, experimental methods, and software that have made protein crystallography a tool accessible to a larger scientific community...
2017: Methods in Molecular Biology
https://www.readbyqxmd.com/read/27893458/requirements-for-dynamical-differential-phase-contrast-x-ray-imaging-with-a-laboratory-source
#16
David Macindoe, Marcus J Kitchen, Sarah C Irvine, Andreas Fouras, Kaye S Morgan
X-ray phase contrast enables weakly-attenuating structures to be imaged, with bright synchrotron sources adding the ability to capture time sequences and analyse sample dynamics. Here, we describe the translation of dynamical differential phase contrast imaging from the synchrotron to a compact x-ray source, in order to achieve this kind of time sequence imaging in the laboratory. We formulate broadly-applicable set-up guidelines for the single-grid, single-exposure imaging technique using a divergent source, exploring the experimental factors that restrict set-up size, imaging sensitivity and sample size...
December 21, 2016: Physics in Medicine and Biology
https://www.readbyqxmd.com/read/27893445/a-method-for-high-energy-low-dose-mammography-using-edge-illumination-x-ray-phase-contrast-imaging
#17
Paul C Diemoz, Alberto Bravin, Anikó Sztrókay-Gaul, Marie Ruat, Susanne Grandl, Doris Mayr, Sigrid Auweter, Alberto Mittone, Emmanuel Brun, Cyril Ponchut, Maximilian F Reiser, Paola Coan, Alessandro Olivo
Since the breast is one of the most radiosensitive organs, mammography is arguably the area where lowering radiation dose is of the uttermost importance. Phase-based x-ray imaging methods can provide opportunities in this sense, since they do not require x-rays to be stopped in tissue for image contrast to be generated. Therefore, x-ray energy can be considerably increased compared to those usually exploited by conventional mammography. In this article we show how a novel, optimized approach can lead to considerable dose reductions...
December 21, 2016: Physics in Medicine and Biology
https://www.readbyqxmd.com/read/27891248/synchrotron-4-dimensional-imaging-of-two-phase-flow-through-porous-media
#18
F H Kim, D Penumadu, P Patel, X Xiao, E J Garboczi, S P Moylan, M A Donmez
Near real-time visualization of complex two-phase flow in a porous medium was demonstrated with dynamic 4-dimensional (4D) (3D + time) imaging at the 2-BM beam line of the Advanced Photon Source (APS) at Argonne National Laboratory. Advancing fluid fronts through tortuous flow paths and their interactions with sand grains were clearly captured, and formations of air bubbles and capillary bridges were visualized. The intense X-ray photon flux of the synchrotron facility made 4D imaging possible, capturing the dynamic evolution of both solid and fluid phases...
2016: MRS Adv
https://www.readbyqxmd.com/read/27890596/monoacyl-phosphatidylcholine-inhibits-the-formation-of-lipid-multilamellar-structures-during-in-vitro-lipolysis-of-self-emulsifying-drug-delivery-systems
#19
Thuy Tran, Scheyla D V S Siqueira, Heinz Amenitsch, Thomas Rades, Anette Müllertz
The colloidal structures formed during lipolysis of self-emulsifying drug delivery systems (SEDDS) might affect the solubilisation and possibly the absorption of drugs. The aim of the current study is to elucidate the structures formed during the in vitro lipolysis of four SEDDS containing medium-chain glycerides and caprylocaproyl polyoxyl-8 glycerides (Labrasol), with or without monoacyl phosphatidylcholine (MAPC). In situ synchrotron small-angle X-ray scattering (SAXS) was combined with ex situ cryogenic transmission electron microscopy (cryo-TEM) and dynamic light scattering (DLS) to elucidate the generated structures...
November 24, 2016: European Journal of Pharmaceutical Sciences
https://www.readbyqxmd.com/read/27890567/commissioning-of-the-4-d-treatment-delivery-system-for-organ-motion-management-in-synchrotron-based-scanning-ion-beams
#20
Mario Ciocca, Alfredo Mirandola, Silvia Molinelli, Stefania Russo, Edoardo Mastella, Alessandro Vai, Andrea Mairani, Giuseppe Magro, Andrea Pella, Marco Donetti, Francesca Valvo, Piero Fossati, Guido Baroni
PURPOSE: The aim of this work was the commissioning of delivery procedures for the treatment of moving targets in scanning pencil beam hadrontherapy. METHODS: EBT3 films fixed to the Anzai Respiratory Phantom were exposed to carbon ion scanned homogeneous fields (E=332MeV/u). To evaluate the interplay effect, field size and flatness for 3 different scenarios were compared to static condition: gated irradiation or repainting alone and combination of both. Respiratory signal was provided by Anzai pressure sensor or optical tracking system (OTS)...
November 24, 2016: Physica Medica: PM
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