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X ray phase contrast

Marlena Whinton, Timothy C Hughes, Shuhua Peng, Michael A Brook
Bicontinuous microemulsions exhibit domain structures on the nanoscale (<20 nm). Normally, such fine details are lost during the conversion from a fluid microemulsion to solid elastomeric materials, as a consequence of interfacial destabilization via polymerization of either the oil phase, or of monomers in the aqueous phase. Very little is known about the polymerization of silicone microemulsions and the morphological changes that occur upon transition from a nanostructured liquid to a solid ma-trix. Silicone microemulsions polymerized by free radical (aqueous phase) and condensation (silicone phase) processes, respective-ly, were characterized by small angle X-ray scattering (SAXS) and transmission electron microscopy (TEM)...
March 16, 2018: Langmuir: the ACS Journal of Surfaces and Colloids
Zhu Liang, Wei Bu, Karl J Schweighofer, David J Walwark, Jeffrey S Harvey, Glenn R Hanlon, Daniel Amoanu, Cem Erol, Ilan Benjamin, Mark L Schlossman
During solvent extraction, amphiphilic extractants assist the transport of metal ions across the liquid-liquid interface between an aqueous ionic solution and an organic solvent. Investigations of the role of the interface in ion transport challenge our ability to probe fast molecular processes at liquid-liquid interfaces on nanometer-length scales. Recent development of a thermal switch for solvent extraction has addressed this challenge, which has led to the characterization by X-ray surface scattering of interfacial intermediate states in the extraction process...
March 12, 2018: Proceedings of the National Academy of Sciences of the United States of America
Mario Mardirossian, Natacha Pérébaskine, Monica Benincasa, Stefano Gambato, Sven Hofmann, Paul Huter, Claudia Müller, Kai Hilpert, C Axel Innis, Alessandro Tossi, Daniel N Wilson
Proline-rich antimicrobial peptides (PrAMPs) internalize into susceptible bacteria using specific transporters and interfere with protein synthesis and folding. To date, mammalian PrAMPs have so far been identified only in artiodactyls. Since cetaceans are co-phyletic with artiodactyls, we mined the genome of the bottlenose dolphin Tursiops truncatus, leading to the identification of two PrAMPs, Tur1A and Tur1B. Tur1A, which is orthologous to the bovine PrAMP Bac7, is internalized into Escherichia coli, without damaging the membranes, using the inner membrane transporters SbmA and YjiL/MdM...
February 22, 2018: Cell Chemical Biology
Henry Jahn, Ivo DE Sena Oliveira, Vladimir Gross, Christine Martin, Alexander Hipp, Georg Mayer, Jörg U Hammel
Non-invasive imaging techniques like X-ray computed tomography have become very popular in zoology, as they allow for simultaneous imaging of the internal and external morphology of organisms. Nevertheless, the effect of different staining approaches required for this method on samples lacking mineralized tissues, such as soft-bodied invertebrates, remains understudied. Herein, we used synchrotron radiation-based X-ray micro-computed tomography to compare the effects of commonly used contrasting approaches on onychophorans - soft-bodied invertebrates important for studying animal evolution...
February 22, 2018: Journal of Microscopy
Jimin Lee, Tae-Yeon Hwang, Min Kyu Kang, Hong-Baek Cho, Jongryoul Kim, Nosang V Myung, Yong-Ho Choa
High-throughput synthesis of Samarium-Cobalt sub-micron fibers with controlled composition and dimension was demonstrated by combining electrospinning and reduction-diffusion processes. The composition of fibers was readily varied (8 < Sm < 20 at.%) by adjusting precursor composition whereas the diameter of fibers was precisely controlled by varying electrospinning parameters (e.g., applied voltage, solution feed rate, temperature, and humidity) to reach single-domain size. X-ray diffraction patterns confirmed that single phase Sm2 Co17 fibers were synthesized when the metal precursor ratio (Sm3+ /(Sm3+ +Co2+ )) was precisely controlled at 10...
2018: Frontiers in Chemistry
Tatyana B Bekker, Vladimir P Solntsev, Sergey V Rashchenko, Alexander P Yelisseyev, Alexey V Davydov, Alexander A Kragzhda, Alexander E Kokh, Artem B Kuznetsov, SoHyun Park
Crystals of the Mnx Ba12 (BO3 )8-2x F8x phase were grown from a high-temperature solution. This new fluoride borate is built of positively charged [Ba12 (BO3 )6 ]6+ blocks, the so-called "anti-zeolite" pattern. Using X-ray single-crystal diffraction, the bulk atomic arrangement in the centrosymmetric tetragonal unit cell in I4/mcm could be elucidated. Crystals of the (MnF6 )4- group-containing solid solution Mnx Ba12 (BO3 )8-2x F8x are dark brown in color in contrast to the differently colored crystals of (LiF4 )3- group-containing "anti-zeolite" LiBa12 (BO3 )7 F4 (P42 bc)...
February 19, 2018: Inorganic Chemistry
Tanja Schulz-Mirbach, Margie Olbinado, Alexander Rack, Alberto Mittone, Alberto Bravin, Roland R Melzer, Friedrich Ladich, Martin Heß
Regarding the basics of ear structure-function relationships in fish, the actual motion of the solid otolith relative to the underlying sensory epithelium has rarely been investigated. Otolith motion has been characterized based on a few experimental studies and on approaches using mathematical modeling, which have yielded partially conflicting results. Those studies either predicted a simple back-and-forth motion of the otolith or a shape-dependent, more complex motion. Our study was designed to develop and test a new set-up to generate experimental data on fish otolith motion in-situ...
February 15, 2018: Scientific Reports
Cressa Ria P Fulong, Junyi Liu, Vincent J Pastore, Haiqing Lin, Timothy R Cook
Discrete metal-organic polyhedra (MOPs) containing copper(ii), palladium(ii), and iron(ii) nodes were synthesized as fillers for mixed-matrix materials (MMMs) with a polyvinylidine fluoride (PVDF) polymer phase and contrasted against an MMM containing a metal-organic framework, MOF-5. When a given MOP was soluble in the precursor solutions, the resulting MMMs were thin, flexible, and homogeneous based on microscopy and SEM imaging. Analogous MMM formation using either insoluble MOPs or the inherent insoluble MOF-5 showed a higher degree of phase separation and inhomogeneity...
February 15, 2018: Dalton Transactions: An International Journal of Inorganic Chemistry
Yuping Feng, Jordina Fornell, Huiyan Zhang, Pau Solsona, Maria Dolors Barό, Santiago Suriñach, Eva Pellicer, Jordi Sort
Open cell foams consisting of Fe and Fe-Mn oxides are prepared from metallic Fe and Mn powder precursors by the replication method using porous polyurethane (PU) templates. First, reticulated PU templates are coated by slurry impregnation. The templates are then thermally removed at 260 °C and the debinded powders are sintered at 1000 °C under N₂ atmosphere. The morphology, structure, and magnetic properties are studied by scanning electron microscopy, X-ray diffraction and vibrating sample magnetometry, respectively...
February 11, 2018: Materials
Anas Z Abidin, Botao Deng, Adora M DSouza, Mahesh B Nagarajan, Paola Coan, Axel Wismüller
Phase contrast X-ray computed tomography (PCI-CT) has been demonstrated to be effective for visualization of the human cartilage matrix at micrometer resolution, thereby capturing osteoarthritis induced changes to chondrocyte organization. This study aims to systematically assess the efficacy of deep transfer learning methods for classifying between healthy and diseased tissue patterns. We extracted features from two different convolutional neural network architectures, CaffeNet and Inception-v3 for characterizing such patterns...
February 9, 2018: Computers in Biology and Medicine
H D Zhou, P M Sarte, B S Conner, L Balicas, C R Wiebe, X H Chen, T Wu, G Wu, R H Liu, H Chen, D F Fang
The fluorine-doped rare-earth iron oxypnictide series SmFeAsO1-x F x (0 [Formula: see text] 0.10) was investigated with high resolution powder x-ray scattering. In agreement with previous studies (Margadonna et al 2009 Phys. Rev. B. 79 014503), the parent compound SmFeAsO exhibits a tetragonal-to-orthorhombic structural distortion at [Formula: see text]  =  130 K which is rapidly suppressed by [Formula: see text] 0.10 deep within the superconducting dome. The change in unit cell symmetry is followed by a previously unreported magnetoelastic distortion at 120 K...
February 12, 2018: Journal of Physics. Condensed Matter: An Institute of Physics Journal
Christian Fedon, Luigi Rigon, Fulvia Arfelli, Diego Dreossi, Elisa Quai, Maura Tonutti, Giuliana Tromba, Maria Assunta Cova, Renata Longo
Two dosimetric quantities [mean glandular dose (MGD) and entrance surface air kerma (ESAK)] and the diagnostic performance of phase-contrast mammography with synchrotron radiation (MSR) are compared to conventional digital mammography (DM). Seventy-one patients (age range, 41 to 82 years) underwent MSR after a DM examination if questionable or suspicious breast abnormalities were not clarified by ultrasonography. The MGD and the ESAK delivered in both examinations were evaluated and compared. Two on-site radiologists rated the images in consensus according to the Breast Imaging Reporting and Data System assessment categories, which were then correlated with the final diagnoses by means of statistical generalized linear models (GLMs)...
January 2018: Journal of Medical Imaging
Hatem A Mahmoud, Katabathini Narasimharao, Tarek T Ali, Kamal M S Khalil
TiO2 nanoparticles were synthesized from titanium isopropoxide by a simple peptization method using sulfuric, nitric, and acetic acids. The effect of peptizing acid on physicochemical and photocatalytic properties of TiO2 powders was studied. The structural properties of synthesized TiO2 powders were analyzed by using XRD, TEM, N2-physisorption, Raman, DR UV-vis, FTIR, and X-ray photoelectron spectroscopy techniques. The characterization results showed that acetic acid peptization facilitated the formation of pure anatase phase after thermal treatment at 500 °C; in contrast, nitric acid peptization led to a major rutile phase formation (67%)...
February 9, 2018: Nanoscale Research Letters
Katharina Hellbach, Ebba Beller, Andreas Schindler, Franziska Schoeppe, Nina Hesse, Alena Baumann, Regina Schinner, Sigrid Auweter, Christian Hauke, Marcus Radicke, Felix G Meinel
PURPOSE: The aim of this study was to investigate whether the detection of foreign bodies can be improved using dark-field and phase-contrast radiography compared with conventional (transmission) radiographs. MATERIALS AND METHODS: Experiments were performed using ex vivo pig paws, which were prepared with differently sized foreign bodies of metal, wood, and glass (n = 10 each). Paws without foreign bodies served as controls (n = 30). All images were acquired using an experimental grating-based large object radiography system...
February 7, 2018: Investigative Radiology
Dionysia Aravopoulou, Konstantinos Kyriakos, Anna Miasnikova, André Laschewsky, Christine M Papadakis, Apostolos Kyritsis
The thermoresponsive behavior of two diblock copolymers PS-b-PNIPAM and PS-b-PMDEGA, which both comprise a hydrophobic polystyrene block but different thermoresponsive blocks, also differing in length, poly(N-isopropylacrylamide) (PNIPAM) and poly(methoxy diethylene glycol acrylate) (PMDEGA), respectively, was comparatively investigated in a wide temperature range. Concentrated aqueous solutions containing 25 wt% polymer, were studied by small-angle X-ray scattering (SAXS), differential scanning calorimetry (DSC) and broadband dielectric spectroscopy (BDS)...
February 8, 2018: Journal of Physical Chemistry. B
Anne-Kathrin Wolfrum, Björn Matthey, Alexander Michaelis, Mathias Herrmann
Cubic boron nitride (c-BN) composites produced at high pressures and temperatures are widely used as cutting tool materials. The advent of new, effective pressure-assisted densification methods, such as spark plasma sintering (SPS), has stimulated attempts to produce these composites at low pressures. Under low-pressure conditions, however, transformation of c-BN to the soft hexagonal BN (h-BN) phase can occur, with a strong deterioration in hardness and wear. In the present work, the influence of secondary phases (B₂O₃, Si₃N₄, and oxide glasses) on the transformation of c-BN was studied in the temperature range between 1100 °C and 1575 °C...
February 7, 2018: Materials
Wataru Yashiro, Daiji Noda, Kentaro Kajiwara
X-ray grating interferometry, which has been spotlighted in the last decade as a multi-modal X-ray imaging technique, can provide three independent images, i.e., absorption, differential-phase, and visibility-contrast images. We report on a cause of the visibility contrast, an effect of insufficient temporal coherence, that can be observed when continuous-spectrum X-rays are used. This effect occurs even for a sample without unresolvable random structures, which are known as the main causes of visibility contrast...
January 22, 2018: Optics Express
Elysse Kompaniez-Dunigan, Craig K Abbey, John M Boone, Michael A Webster
We examined how visual sensitivity and perception are affected by adaptation to the characteristic amplitude spectra of X-ray mammography images. Because of the transmissive nature of X-ray photons, these images have relatively more low-frequency variability than natural images, a difference that is captured by a steeper slope of the amplitude spectrum (~ - 1.5) compared to the ~ 1/f (slope of - 1) spectra common to natural scenes. Radiologists inspecting these images are therefore exposed to a different balance of spectral components, and we measured how this exposure might alter spatial vision...
2018: Cognitive Research: Principles and Implications
Dongxu Pan, Yongping Fu, Jie Chen, Kyle J Czech, John C Wright, Song Jin
The facile chemical transformation of metal halide perovskites via ion exchange has been attributed to their "soft" crystal lattices that enable fast ion migration. Kinetic studies of such processes could provide mechanistic insights on the ion migration dynamics. Herein, by using aligned single-crystal nanowires of cesium lead bromide (CsPbBr3) perovskite on epitaxial substrates as platforms, we visualize and investigate the cation or anion interdiffusion kinetics via spatially resolved photoluminescence measurement on heterostructures fabricated by stacking CsPbCl3, MAPbI3, or MAPbBr3 microplates on top of CsPbBr3 nanowires...
February 3, 2018: Nano Letters
Florian Horn, Martino Leghissa, Sebastian Kaeppler, Georg Pelzer, Jens Rieger, Maria Seifert, Johannes Wandner, Thomas Weber, Thilo Michel, Christian Riess, Gisela Anton
X-ray grating-based phase-contrast imaging has raised interest regarding a variety of potential clinical applications, whereas the method is feasible using a medical x-ray tube. Yet, the transition towards a clinical setup remains challenging due to the requirement of mechanical robustness of the interferometer and high demands applying to medical equipment in clinical use. We demonstrate the successful implementation of a Talbot-Lau interferometer in an interventional c-arm setup. The consequence of vibrations induced by the rotating anode of the tube is discussed and the prototype is shown to provide a visibility of 21...
February 2, 2018: Scientific Reports
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