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X ray phase contrast

A D Surowka, M Töpperwien, M Bernhardt, J D Nicolas, M Osterhoff, T Salditt, D Adamek, M Szczerbowska-Boruchowska
Human dopaminergic system in general, and substantia nigra (SN) neurons, in particular, are implicated in the pathologies underlying the human brain aging. The interplay between aberrations in the structural organization and elemental composition of SN neuron bodies has recently gained in importance as selected metals: Fe, Cu, Zn, Ca were found to trigger oxidative-stress-mediated aberration in their molecular assembly due to concomitant protein (alpha-synuclein, tau-protein) aggregation, gliosis and finally oxidative stress...
December 1, 2016: Talanta
Fang Mao, Mamoun Taher, Oleksandr Kryshtal, Adam Kruk, Aleksandra Czyrska-Filemonowicz, Mikael Ottosson, Anna Mikaela Andersson, Urban Wiklund, Ulf Jansson
A combinatorial approach is applied to rapidly deposit and screen Ag-Al thin films to evaluate the mechanical, tribological and electrical properties as a function of chemical composition. Ag-Al thin films with large continuous composition gradients (6-60 at.% Al) were deposited by a custom-designed combinatorial magnetron sputtering system. X-ray diffraction (XRD), energy dispersive X-ray spectroscopy (EDX), scanning and transmission electron microscopy (SEM & TEM), X-ray photoelectron spectroscopy (XPS), nanoindentation, and four-point electrical resistance screening were employed to characterize the chemical composition, structure and physical properties of the films in a rapid and time-efficient way...
October 17, 2016: ACS Applied Materials & Interfaces
Houxun Miao, Alireza Panna, Andrew A Gomella, Eric E Bennett, Sami Znati, Lei Chen, Han Wen
A moiré pattern is created by superimposing two black-and-white or gray-scale patterns of regular geometry, such as two sets of evenly spaced lines. We observed an analogous effect between two transparent phase masks in a light beam which occurs at a distance. This phase moiré effect and the classic moiré effect are shown to be the two ends of a continuous spectrum. The phase moiré effect allows the detection of sub-resolution intensity or phase patterns with a transparent screen. When applied to x-ray imaging, it enables a polychromatic far-field interferometer (PFI) without absorption gratings...
2016: Nature Physics
Lorenzo Massimi, Michela Fratini, Inna Bukreeva, Francesco Brun, Alberto Mittone, Gaetano Campi, Raffaele Spanò, Milena Mastrogiacomo, Nicole Kerlero de Rosbo, Alberto Bravin, Antonio Uccelli, Alessia Cedola
High resolution Synchrotron-based X-ray Phase Contrast Tomography (XPCT) allows the simultaneous detection of three dimensional neuronal and vascular networks without using contrast agents or invasive casting preparation. We show and discuss the different features observed in reconstructed XPCT volumes of the ex vivo mouse spinal cord in the lumbo-sacral region, including motor neurons and blood vessels. We report the application of an intensity-based segmentation method to detect and quantitatively characterize the modification in the vascular networks in terms of reduction in experimental visibility...
October 12, 2016: Physica Medica: PM
Andrea Nardini, Tadeja Savi, Adriano Losso, Giai Petit, Serena Pacilè, Giuliana Tromba, Stefan Mayr, Patrizia Trifilò, Maria A Lo Gullo, Sebastiano Salleo
Drought-induced xylem embolism is a serious threat to plant survival under future climate scenarios. Hence, accurate quantification of species-specific vulnerability to xylem embolism is a key to predict the impact of climate change on vegetation. Low-cost hydraulic measurements of embolism rate have been suggested to be prone to artefacts, thus requiring validation by direct visualization of the functional status of xylem conduits using nondestructive imaging techniques, such as X-ray microtomography (microCT)...
October 13, 2016: New Phytologist
Sabrina Seidel, Christian Patzig, Wolfgang Wisniewski, Antje Gawronski, Yongfeng Hu, Thomas Höche, Christian Rüssel
The non-isochemical crystallization of glasses leads to glass-ceramics in which the chemical composition of the amorphous matrix differs from that of the parent glass. It is challenging to solely analyse the properties of these residual glassy phases because they frequently contain finely dispersed crystals. In this study, the composition of the residual glass matrix after the crystallization of a glass with the mol% composition 50.6 SiO2 · 20.7 MgO · 20.7 Al2O3 · 5.6 ZrO2 · 2.4 Y2O3 is analysed by scanning transmission electron microscopy (STEM) including energy dispersive X-ray analysis (EDXS)...
October 13, 2016: Scientific Reports
Antonio Sarno, Giovanni Mettivier, Francesca Di Lillo, Mario Cesarelli, Paolo Bifulco, Paolo Russo
We developed a scanner for micro computed tomography dedicated to the breast (BµCT) with a high resolution flat-panel detector and a microfocus X-ray tube. We evaluated the system spatial resolution via the 3D modulation transfer function (MTF). In addition to conventional absorption-based X-ray imaging, such a prototype showed capabilities for propagation-based phase-contrast and related edge enhancement effects in 3D imaging. The system limiting spatial resolution is 6.2mm(-1) (MTF at 10%) in the vertical direction and 3...
October 7, 2016: Medical Engineering & Physics
Ryuta Mizutani, Rino Saiga, Masato Ohtsuka, Hiromi Miura, Masato Hoshino, Akihisa Takeuchi, Kentaro Uesugi
Neurons transmit active potentials through axons, which are essential for the brain to function. In this study, the axonal networks of the murine brain were visualized with X-ray tomographic microscopy, also known as X-ray microtomography or micro-CT. Murine brain samples were freeze-dried to reconstitute the intrinsic contrast of tissue constituents and subjected to X-ray visualization. A whole brain hemisphere visualized by absorption contrast illustrated three-dimensional structures including those of the striatum, corpus callosum, and anterior commissure...
October 11, 2016: Scientific Reports
Jason A Dunlop, Dmitry A Apanaskevich, Jens Lehmann, René Hoffmann, Florian Fusseis, Moritz Ehlke, Stefan Zachow, Xianghui Xiao
BACKGROUND: Fossil ticks are extremely rare and Ixodes succineus Weidner, 1964 from Eocene (ca. 44-49 Ma) Baltic amber is one of the oldest examples of a living hard tick genus (Ixodida: Ixodidae). Previous work suggested it was most closely related to the modern and widespread European sheep tick Ixodes ricinus (Linneaus, 1758). RESULTS: Restudy using phase contrast synchrotron x-ray tomography yielded images of exceptional quality. These confirm the fossil's referral to Ixodes Latreille, 1795, but the characters resolved here suggest instead affinities with the Asian subgenus Partipalpiger Hoogstraal et al...
October 10, 2016: BMC Evolutionary Biology
Stefan Permien, Sylvio Indris, Gero Neubüser, Andy Fiedler, Lorenz Kienle, Stefan Zander, Stephen Doyle, Björn Richter, Wolfgang Bensch
A composite consisting of CoFe2 O4 spinel nanoparticles and reduced graphite oxide (rGO) is studied as an anode material during Li uptake and release by applying synchrotron operando X-ray diffraction (XRD) and operando X-ray absorption spectroscopy (XAS), yielding a comprehensive picture of the reaction mechanisms. In the early stages of Li uptake, a monoxide is formed as an intermediate phase containing Fe(2+) and Co(2+) ions; this observation is in contrast to reaction pathways proposed in the literature...
October 10, 2016: Chemistry: a European Journal
Mette Andersen Borup, Anders Bank Blichfeld, Solveig Røgild Madsen, Bo Brummerstedt Iversen
The structures of thermoelectric ZnSb and Zn4Sb3 have been studied extensively as a function of temperature but not in detail as a function of pressure. High pressure single crystal X-ray diffraction data allow structure refinements of ZnSb and Zn4Sb3 up to 12.8(2) GPa and 10.6(2) GPa, respectively, and in contrast to previous reports without any signs of phase transitions. At high pressure a redistribution of Zn in Zn4Sb3 is present, which is distinctly different from the thermal response of the structure...
September 27, 2016: Dalton Transactions: An International Journal of Inorganic Chemistry
Fei Zhang, Masanao Inokoshi, Maria Batuk, Joke Hadermann, Ignace Naert, Bart Van Meerbeek, Jef Vleugels
OBJECTIVE: The aim was to evaluate the optical properties, mechanical properties and aging stability of yttria-stabilized zirconia with different compositions, highlighting the influence of the alumina addition, Y2O3 content and La2O3 doping on the translucency. METHODS: Five different Y-TZP zirconia powders (3 commercially available and 2 experimentally modified) were sintered under the same conditions and characterized by X-ray diffraction with Rietveld analysis and scanning electron microscopy (SEM)...
September 30, 2016: Dental Materials: Official Publication of the Academy of Dental Materials
Qi Wang, Ajinkya Puntambekar, Vidhya Chakrapani
Metal-insulator transitions in strongly correlated oxides induced by electrochemical charging have been attributed to formation of vacancy defects. However, the role of native defects in affecting these transitions is not clear. Here, we report a new type of phase transition in p-type, non-stoichiometric nickel oxide involving a semiconductor-to-insulator-to-metal transition along with the complete reversal of conductivity from p- to n-type at room temperature induced by electrochemical charging in a Li+-containing electrolyte...
October 3, 2016: Nano Letters
Elena Longo, Federica Ciuchi, Rita Guzzi, Bruno Rizzuti, Rosa Bartucci
Resveratrol is a natural polyphenol found in various plants with potential therapeutic activity as anti-oxidant, anti-inflammatory, cardioprotective and anti-tumoral. Lipid membranes are among cellular components that are targets of its action. In this work ESR of chain labeled lipids, calorimetry, X-ray diffraction and molecular docking are used to study the interaction of resveratrol with membrane model systems of dipalmitoylphosphatidylcholine (DPPC) as a function of resveratrol concentration (0-30 mol% of the lipid) and temperature (10-50°C)...
September 28, 2016: Colloids and Surfaces. B, Biointerfaces
Tomoki Nishimura, Maxym Alexandrov, Takenori Ishida, Ryuichi Hirota, Takeshi Ikeda, Kiyoshi Sekiguchi, Akio Kuroda
Considering the increasing use of various asbestos substitutes, asbestos risk management in many industries may require accurate techniques for detecting and distinguishing asbestos from non-asbestos fibers. Using fluorescently labeled asbestos-binding proteins, we previously developed a novel method for detection and counting of asbestos fibers under fluorescence microscopy (FM). This method can provide speedy, on-site detection and identification of the asbestos fibers and has higher sensitivity than phase contrast microscopy (PCM)...
September 26, 2016: Annals of Occupational Hygiene
Patrick Pietsch, Daniel Westhoff, Julian Feinauer, Jens Eller, Federica Marone, Marco Stampanoni, Volker Schmidt, Vanessa Wood
Despite numerous studies presenting advances in tomographic imaging and analysis of lithium ion batteries, graphite-based anodes have received little attention. Weak X-ray attenuation of graphite and, as a result, poor contrast between graphite and the other carbon-based components in an electrode pore space renders data analysis challenging. Here we demonstrate operando tomography of weakly attenuating electrodes during electrochemical (de)lithiation. We use propagation-based phase contrast tomography to facilitate the differentiation between weakly attenuating materials and apply digital volume correlation to capture the dynamics of the electrodes during operation...
2016: Nature Communications
Aidin Lak, Dina Niculaes, George C Anyfantis, Giovanni Bertoni, Markus J Barthel, Sergio Marras, Marco Cassani, Simone Nitti, Athanassia Athanassiou, Cinzia Giannini, Teresa Pellegrino
Here, we propose the use of magnetic hyperthermia as a means to trigger the oxidation of Fe1-xO/Fe3-δO4 core-shell nanocubes to Fe3-δO4 phase. As a first relevant consequence, the specific absorption rate (SAR) of the initial core-shell nanocubes doubles after exposure to 25 cycles of alternating magnetic field stimulation. The improved SAR value was attributed to a gradual transformation of the Fe1-xO core to Fe3-δO4, as evidenced by structural analysis including high resolution electron microscopy and Rietveld analysis of X-ray diffraction patterns...
September 26, 2016: Scientific Reports
Jermaine L Jenkins, Joseph E Wedekind
Ribozymes and riboswitches are examples of non-protein-coding (nc)RNA molecules that achieve biological activity by adopting complex three-dimensional folds. Visualization of such molecules at near-atomic resolution can enhance our understanding of how chemical groups are organized spatially, thereby providing novel insight into function. This approach has its challenges, which mainly entail sample crystallization followed by the application of empirical, structure-determination methods that often include experimental "phasing" of X-ray diffraction data...
2016: Methods in Molecular Biology
Maïtena Dumont, Paul Tafforeau, Thomas Bertin, Bhart-Anjan Bhullar, Daniel Field, Anne Schulp, Brandon Strilisky, Béatrice Thivichon-Prince, Laurent Viriot, Antoine Louchart
BACKGROUND: The dentitions of extinct organisms can provide pivotal information regarding their phylogenetic position, as well as paleobiology, diet, development, and growth. Extant birds are edentulous (toothless), but their closest relatives among stem birds, the Cretaceous Hesperornithiformes and Ichthyornithiformes, retained teeth. Despite their significant phylogenetic position immediately outside the avian crown group, the dentitions of these taxa have never been studied in detail...
2016: BMC Evolutionary Biology
Alexander Clout, Asma B M Buanz, Timothy J Prior, Christina Reinhard, Yue Wu, Dermot O'Hare, Gareth R Williams, Simon Gaisford
We report a powerful new technique: hyphenating synchrotron X-ray powder diffraction (XRD) with differential scanning calorimetry (DSC). This is achieved with a simple modification to a standard laboratory DSC instrument, in contrast to previous reports which have involved extensive and complex modifications to a DSC to mount it in the synchrotron beam. The high-energy X-rays of the synchrotron permit the recording of powder diffraction patterns in as little as 2 s, meaning that thermally induced phase changes can be accurately quantified and additional insight on the nature of phase transitions obtained...
October 18, 2016: Analytical Chemistry
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