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X ray phase contrast

L Weber, A Hänsch, U Wolfram, A Pacureanu, P Cloetens, F Peyrin, S Rit, M Langer
X-ray phase tomography aims at reconstructing the 3D electron density distribution of an object. It offers enhanced sensitivity compared to attenuation-based X-ray absorption tomography. In propagation-based methods, phase contrast is achieved by letting the beam propagate after interaction with the object. The phase shift is then retrieved at each projection angle, and subsequently used in tomographic reconstruction to obtain the refractive index decrement distribution, which is proportional to the electron density...
August 16, 2017: Journal of Microscopy
Maria Dobies, Monika Makrocka-Rydzyk, Jacek Jenczyk, Marcin Jarek, Richard J Spontak, Stefan Jurga
Two polystyrene-b-poly(ethylene oxide) (PS-b-PEO) diblock copolymers differing in molecular mass (49 and 78 kDa), but possessing the same PEO cylindrical morphology, are examined to elucidate their molecular dynamics. Of particular interest here is the molecular motion of the PEO blocks involved in the rigid amorphous fraction (RAF). Analysis of complementary thermal calorimetry and X-ray scattering data confirm the presence of a microphase-separated morphology, as well as semi-crystalline structure, in each copolymer...
August 16, 2017: Langmuir: the ACS Journal of Surfaces and Colloids
Sanghun Jang, Jaehong Lim, Onseok Lee
Radiation beam interface contrast X-ray microscopy provides resolution of a few dozen nanometers from fixed whole muscle biopsies, allowing better reconstruction of the microstructure of the muscle than is currently possible with classic histological techniques. Fixed soleus muscle biopsies have been evaluated from the walk-in mouse model using phase-contrast X-ray microscopy, and results presented that corroborate the accuracy of the method used, and its potential for application in physiotherapy and occupational therapy studies...
August 12, 2017: Microscopy Research and Technique
Svetlana V Kameneva, Daniil A Tyurin, Kirill B Nuzhdin, Vladimir I Feldman
Spectroscopic characteristics and X-ray induced transformations of the HCN⋯CO2 complex in solid Ar and Kr matrices were studied by FTIR spectroscopy and ab initio calculations at the CCSD(T) level. The complex was prepared by deposition of the HCN/CO2/Ng gas mixtures (Ng = Ar or Kr). The comparison of the experiment and calculations prove formation of a linear, H-bonded NCH⋯OCO complex with a substantial red shift of the C-H stretching band and a blue shift of the H-C-N bending band in respect to the monomer...
December 7, 2016: Journal of Chemical Physics
Marietta Andrea Markus, Sergej Borowik, Marius Reichardt, Giuliana Tromba, Frauke Alves, Christian Dullin
Chronic asthma patients experience difficulties even years after the inciting allergen. Although studies in small animal asthma models have enormously advanced progress in uncovering the mechanisms of inception and development of the disease, little is known about the processes involved in the persistence of asthma symptoms in the absence of allergen exposure. Long term asthma mouse models have so far been scarce or not been able to reproduce the findings in patients. Here we used a common ovalbumin induced acute allergic airway inflammation mouse model to study lung function and remodeling after a four months recovery period...
August 3, 2017: American Journal of Physiology. Lung Cellular and Molecular Physiology
Erin Victoria McGillick, Katie Lee, Shigeo Yamaoka, Arjan B Te Pas, Kelly J Crossley, Megan J Wallace, Marcus John Kitchen, Robert A Lewis, Lauren T Kerr, Philip DeKoninck, Janneke Dekker, Marta Thio, Annie McDougall, Stuart B Hooper
Excessive liquid in airways and/or in distal lung tissue may underpin the respiratory morbidity associated with transient tachypnea of the newborn (TTN). However, its effects on lung aeration and respiratory function following birth are unknown. We investigated the effect of elevated airway liquid volumes on newborn respiratory function. Near term rabbit kittens (30 days gestation; term ~32 days) were delivered, had lung liquid drained and either had no liquid replaced (Control, n=7) or 30 mL/kg of liquid was re-added to the airways (liquid added; LA, n=7)...
August 3, 2017: Journal of Applied Physiology
Hung-Bin Lee, Hsueh-Chuan Hsu, Shih-Ching Wu, Shih-Kuang Hsu, Peng-Hsiang Wang, Wen-Fu Ho
We propose a simple and low-cost process for the preparation of porous Ti foams through a sponge replication method using single-step air sintering at various temperatures. In this study, the apatite-forming ability of air-sintered Ti samples after 21 days of immersion in simulated body fluid (SBF) was investigated. The microstructures of the prepared Ca-P deposits were examined by X-ray diffraction (XRD), field-emission scanning electron microscopy (FE-SEM), Fourier transform infrared (FTIR) spectroscopy, and cross-sectional transmission electron microscopy (TEM)...
November 24, 2016: Materials
Guodong Xiong, Bolin Wu, Tingting Wu
This paper investigated the effect of Pr₆O11 addition on the acid resistance of ceramic proppant. Acid resistance of proppants can be improved by introducing Pr₆O11 into the Al₂O₃-CaO-MgO-SiO₂ (ACMS) system. To illustrate and explain the mechanism of acid resistance, the samples were characterized by different techniques, using X-ray powder diffraction (XRD) and scanning electron microscopy (SEM). The phase structure of the specimens was characterized by XRD and SEM-detected microstructures of the specimens...
April 19, 2017: Materials
Sachin M Bhosle, Craig R Friedrich
The amorphous to anatase transformation of anodized nanotubular titania surfaces has been studied by X-ray diffraction and transmission electron microscopy. A more rapid heat treatment for conversion of amorphous to crystalline anatase favorable for orthopedic implant applications was demonstrated. Nanotube titania surfaces were fabricated by electrochemical anodization of Ti6Al4V in an electrolyte containing 0.2 wt% NH4F, 60% ethylene glycol and 40% deionized water. The resulting surfaces were systematically heat treated in air with isochronal and isothermal experiments to study the temperature and time dependent transformation respectively...
August 2, 2017: Nanotechnology
Jia Xu, Yuxin Sun, Tianyi Wu, Yang Liu, Liu Shi, Jinfang Zhang, Qinglin Kang, Yimin Chai, Gang Li
Axial micromotion of bone fragments promotes callus formation and bone healing during the process of distraction osteogenesis (DO). The present study investigated the effects of the combined axial compression and distraction (accordion) technique on bone regeneration in rat DO model. Male Sprague-Dawley rats (n = 62) underwent right tibial transverse osteotomy, and were randomly divided into four groups after lengthening: control (no manipulation) and three experimental groups assigned based on the period of accordion maneuvers in the consolidation phase (Groups 1, 2, and 3 with accordion technique applied at weeks 1, 3, and 5, respectively)...
August 1, 2017: Journal of Tissue Engineering and Regenerative Medicine
F Horn, K Gelse, S Jabari, C Hauke, S Kaeppler, V Ludwig, P Meyer, T Michel, J Mohr, G Pelzer, J Rieger, C Riess, M Seifert, G Anton
We report on a radiographic measurement of an ex vivo human knee using a grating-based phase-contrast imaging setup and a medical x-ray tube at a tube voltage of 70 kV. The measurement has been carried out using a Talbot-Lau setup that is suitable to achieve a high visibility in the energy regime of medical imaging. In a medical reading by an experienced trauma surgeon signatures of chondrocalcinosis in the medial meniscus have been identified more evidently using the dark-field image in comparison to the conventional attenuation image...
August 1, 2017: Physics in Medicine and Biology
Shivaji Bachche, Masahiro Nonoguchi, Koichi Kato, Masashi Kageyama, Takafumi Koike, Masaru Kuribayashi, Atsushi Momose
An X-ray Talbot-Lau interferometer scanning setup consisting of three transmission gratings, a laboratory-based X-ray source that emits X-rays vertically, and an image detector on the top has been developed for the application of X-ray phase imaging to moving objects that cannot be tested clearly with conventional absorption contrast. The grating-based X-ray phase imaging method usually employs a phase-stepping (or fringe-scanning) technique by displacing one of the gratings step-by-step while the object stays still...
July 27, 2017: Scientific Reports
Tiansheng Liu, Chao He, Fengying Wang, Yingbin Liu, Xiaoxiang Xi, Ruidan Zhong, Genda Gu
We report a shockwave method for altering the properties of the superconductor material Bi2Sr2CaCu2O8+δ (Bi2212). We find that the superconducting transition temperature (T c) increases from 84 K for the pristine sample to 94 K for the sample treated at a temperature and pressure of ~1200 K and ~31 GPa, respectively. X-ray diffraction and transmission electron microscopy characterizations indicate that this T c enhancement arises from a phase transition from pristine Bi2212 to a mixture of superconducting Bi2212 and semiconducting Bi2Sr2CuO6+δ (Bi2201) during the shockwave treatment...
July 27, 2017: Scientific Reports
Baran Eren, Heath Kersell, Robert S Weatherup, Christian Heine, Ethan J Crumlin, Cynthia M Friend, Miquel B Salmeron
Using ambient pressure X-ray photoelectron spectroscopy (APXPS) and high pressure scanning tunneling microscopy (HPSTM), we show that in equilibrium with 0.01-0.2 Torr of methanol vapor, at room temperature, the Cu(100) surface is covered with methoxy species forming a c(2 × 2) overlayer structure. In contrast, no methoxy is formed if the surface is saturated with an ordered oxygen layer, even when the methanol pressure is 0.2 Torr. At oxygen coverages below saturation, methanol dissociates and reacts with the atomic oxygen, producing methoxy and formate on the surface, and formaldehyde that desorbs to the gas phase...
August 14, 2017: Journal of Physical Chemistry. B
E Troja, V M Lipunov, C G Mundell, N R Butler, A M Watson, S Kobayashi, S B Cenko, F E Marshall, R Ricci, A Fruchter, M H Wieringa, E S Gorbovskoy, V Kornilov, A Kutyrev, W H Lee, V Toy, N V Tyurina, N M Budnev, D A H Buckley, J González, O Gress, A Horesh, M I Panasyuk, J X Prochaska, E Ramirez-Ruiz, R Rebolo Lopez, M G Richer, C Román-Zúñiga, M Serra-Ricart, V Yurkov, N Gehrels
Newly formed black holes of stellar mass launch collimated outflows (jets) of ionized matter that approach the speed of light. These outflows power prompt, brief and intense flashes of γ-rays known as γ-ray bursts (GRBs), followed by longer-lived afterglow radiation that is detected across the electromagnetic spectrum. Measuring the polarization of the observed GRB radiation provides a direct probe of the magnetic fields in the collimated jets. Rapid-response polarimetric observations of newly discovered bursts have probed the initial afterglow phase, and show that, minutes after the prompt emission has ended, the degree of linear polarization can be as high as 30 per cent-consistent with the idea that a stable, globally ordered magnetic field permeates the jet at large distances from the central source...
July 26, 2017: Nature
A Ruhlandt, M Töpperwien, M Krenkel, R Mokso, T Salditt
We present an approach towards four dimensional (4d) movies of materials, showing dynamic processes within the entire 3d structure. The method is based on tomographic reconstruction on dynamically curved paths using a motion model estimated by optical flow techniques, considerably reducing the typical motion artefacts of dynamic tomography. At the same time we exploit x-ray phase contrast based on free propagation to enhance the signal from micron scale structure recorded with illumination times down to a millisecond (ms)...
July 26, 2017: Scientific Reports
Sandra Haschke, Dmitrii Pankin, Yuri Petrov, Sebastian Bochmann, Alina Manshina, Julien Bachmann
Nanotubular iron(III) oxide electrodes are optimized for catalytic proficiency in the water oxidation reaction at neutral pH. Nanostructured electrodes are prepared from anodic alumina templates coated with Fe2O3 by atomic layer deposition. Scanning helium ion microscopy, X-ray diffraction and Raman spectroscopy characterize the morphology and phase of samples submitted to various treatments. These methods document the contrasting effects of thermal annealing, on the one hand, and of electrochemical treatment, on the other hand...
July 26, 2017: ChemSusChem
Maxence Carrel, Mario A Beltran, Verónica L Morales, Nicolas Derlon, Eberhard Morgenroth, Rolf Kaufmann, Markus Holzner
X-ray tomography is a powerful tool giving access to the morphology of biofilms, in 3D porous media, at the mesoscale. Due to the high water content of biofilms, the attenuation coefficient of biofilms and water are very close, hindering the distinction between biofilms and water without the use of contrast agents. Until now, the use of contrast agents such as barium sulfate, silver-coated micro-particles or 1-chloronaphtalene added to the liquid phase allowed imaging the biofilm 3D morphology. However, these contrast agents are not passive and potentially interact with the biofilm when injected into the sample...
2017: PloS One
Eunjue Yi, Sung-Mi Han, Ji-Eun Chang, Hong-Tae Kim, Jong-Ki Kim, Seung-Jun Seo, Jin-Haeng Chung, Sanghoon Jheon
High-resolution tomographic images using synchrotron X-rays are expected to provide detailed reflection of microstructures, thereby allowing for the examination of histologic structures without destruction of the specimen. This study aims to evaluate the synchrotron tomographic images of mixed ground-glass opacity excised on 5-mm sections in comparison to pathologic examination. The Institutional Review Board of our institute approved this retrospective study, and written informed consent was obtained from each patient whose lung tissue would be used...
July 21, 2017: Microscopy Research and Technique
Bartłomiej Włodarczyk, Jakub Pietrzak
Here, we present a hybrid approach for simulating an edge illumination X-ray phase-contrast imaging (EIXPCi) set-up using graphics processor units (GPU) with a high degree of accuracy. In this study, the applicability of pixel, mesh and non-uniform rational B-splines (NURBS) objects to carry out realistic maps of X-ray phase-contrast distribution at a human scale is accounted for by using numerical anthropomorphic phantoms and a very fast and robust simulation framework which integrates total interaction probabilities along selected X-ray paths...
July 17, 2017: Physica Medica: PM
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