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X ray phase contrast

Xu Ji, Yongshuai Ge, Ran Zhang, Ke Li, Guang-Hong Chen
PURPOSE: In grating-based x-ray multi-contrast imaging, signals of three contrast mechanisms-absorption contrast, differential phase contrast (DPC), and dark-field contrast-can be estimated from the same set of acquired data. The estimated sig-nals, N0 (related to absorption), N1 (related to dark-field), and ϕ (related to DPC) may be intrinsically biased. However, it is yet unclear how large these biases are and how the data acquisition parameters affect the biases in the extracted signals...
March 24, 2017: Medical Physics
Victoria Ewan, Thomas Hellyer, Julia Newton, John Simpson
Approximately 1.5% of hospital patients develop hospital acquired pneumonia. Aspiration is the major risk factor for pneumonia and is associated with reduced ability to mechanically clear respiratory pathogens into the stomach. Currently non-invasive methods of diagnosing hospital acquired pneumonia are less robust than invasive methods, and lead to over-diagnosis. Accurate diagnosis is key to surveillance, prevention and treatment of HAP, and also to improving outcomes; newer imaging modalities such as phase contrast X-ray imaging and nanoparticle enhanced magnetic resonance imaging may help...
February 27, 2017: Age and Ageing
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
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
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
Galina Marzun, Helmut Bönnemann, Christian Lehmann, Bernd Spliethoff, Claudia Weidenthaler, Stephan Barcikowski
The role of molecular oxygen dissolved in the solvent is often discussed as being an influential factor on particle oxidation during pulsed laser ablation in liquids. However, the formation of the particles during laser synthesis takes place under extreme conditions that enable the decomposition of the liquid medium. Reactive species of the solvent may then affect particle formation due to a chemical reaction in the reactive plasma. Experimental results show a difference between the role of dissolved molecular oxygen and the contribution from the oxygen in water molecules...
March 20, 2017: Chemphyschem: a European Journal of Chemical Physics and Physical Chemistry
Miho Osaka, Aoi Ishikawa, Shigehito Yamada, Chigako Uwabe, Hirohiko Imai, Tetsuya Matsuda, Akio Yoneyama, Tohoru Takeda, Tetsuya Takakuwa
The present study aimed to describe the positional changes of the ocular organs during craniofacial development; moreover, we examined the relationships among the ocular organs and other internal structures. To do this, we traced the positions of the ocular organs in 56 human early fetal samples at different stages of development using high-resolution magnetic resonance imaging and phase-contrast X-ray computed tomography. The eyes were located on the lateral side in the ventral view at Carnegie stage (CS) 16, and then changed their positions medially during development...
March 13, 2017: Anatomical Record: Advances in Integrative Anatomy and Evolutionary Biology
Orsolya Dömötör, Veronika F S Pape, Nóra V May, Gergely Szakács, Éva A Enyedy
Complex formation processes of [Ru(η(6)-p-cymene)(H2O)3](+) and [Rh(η(5)-C5Me5)(H2O)3](+) organometallic cations with 8-hydroxyquinoline (HQ) ligands were studied in aqueous solution by the combined use of (1)H NMR spectroscopy, UV-visible spectrophotometry and pH-potentiometry. Solution stability, chloride ion affinity and lipophilicity of the complexes were characterized together with the in vitro cytotoxicity against a pair of cancer cell lines, responsive and resistant to classic chemotherapy. The solid phase structure of the [Rh(η(5)-C5Me5)(8-quinolinolato)(Cl)] complex was characterized by single-crystal X-ray diffraction analysis...
March 13, 2017: Dalton Transactions: An International Journal of Inorganic Chemistry
Gregory S Hutchings, Jin-Hao Jhang, Chao Zhou, David Hynek, Udo D Schwarz, Eric I Altman
Epitaxial strain can be a powerful parameter for directing the growth of thin films. Unfortunately, conventional materials only offer discrete choices for setting the lattice strain. In this work, it is demonstrated that epitaxial growth of transition metal alloy solid solutions can provide thermally stable, high-quality growth substrates with continuously tunable lattice constants. Molecular beam epitaxy was used to grow NixPd1-x(111) alloy films with lattice constants between 3.61 and 3.89 Å on the hexagonal (0001) basal planes of α-Al2O3 and Cr2O3 (grown as epitaxial films on α-Al2O3 (0001))...
March 20, 2017: ACS Applied Materials & Interfaces
Irvin Teh, Darryl McClymont, Marie-Christine Zdora, Hannah J Whittington, Valentina Davidoiu, Jack Lee, Craig A Lygate, Christoph Rau, Irene Zanette, Jürgen E Schneider
BACKGROUND: Diffusion tensor imaging (DTI) is widely used to assess tissue microstructure non-invasively. Cardiac DTI enables inference of cell and sheetlet orientations, which are altered under pathological conditions. However, DTI is affected by many factors, therefore robust validation is critical. Existing histological validation is intrinsically flawed, since it requires further tissue processing leading to sample distortion, is routinely limited in field-of-view and requires reconstruction of three-dimensional volumes from two-dimensional images...
March 10, 2017: Journal of Cardiovascular Magnetic Resonance
Mercouri G Kanatzidis
The discovery of new materials and their efficient syntheses is a fundamental goal of chemistry. A related objective is to identify foundational and rational approaches to enhance the art of synthesis by combining the exquisite predictability of organic synthesis with the high yields of solid-state chemistry. In contrast to so-called solid-state methods, inorganic syntheses in liquid fluxes permit bond formation, framework assembly, and crystallization at lower temperatures because of facile diffusion and chemical reactions with and within the flux itself...
March 9, 2017: Inorganic Chemistry
Pengzhi Guo, Guoping Luo, Qiang Su, Jianfeng Li, Peng Zhang, Junfeng Tong, Chunyan Yang, Yangjun Xia, Hongbin Wu
The photovoltaic cells (PVCs) from conjugated copolymers of PDTBDT-BT and PDTBDT-FBT with 5,10-bis(4,5-didecylthien-2-yl)dithieno[2,3-d:2',3'-d']benzo[1,2-b:4,5-b']dithiophene as electron donor moieties and benzothiadiazole and/or 5,6-difluorobenzothiadiazole as electron acceptor moieties are optimized by employing alcohol-soluble PFN (poly(9,9-bis(3'-(N,N-dimethylamino)propyl)-2,7-fluorene)-alt-2,7-(9,9-dioctylfluorene)) as cathode modification interlayer. The power conversion efficiencies (PCEs) of inverted PVCs (i-PVCs) from PDTBDT-BT and PDTBDT-FBT with devices configuration as ITO/PFN/active layer/MoO3/Ag are increased from 4...
March 20, 2017: ACS Applied Materials & Interfaces
Sebastian Kaeppler, Maria Seifert, Florian Horn, Georg Pelzer, Jens Rieger, Thilo Michel, Andreas Maier, Gisela Anton, Christian Riess
PURPOSE: Grating-based Talbot-Lau interferometers are a popular choice for phase-contrast X-ray acquisitions. Here, an air reference scan has to be acquired prior to an object scan. This particularly complicates acquisition of large objects: large objects are tiled into multiple scans due to the small field of view of current gratings. However, phase reference drifts occurring between these scans may require to repeatedly move the object in and out of the X-ray beam to update the reference information...
March 9, 2017: Medical Physics
Tomoya Onozuka, Akira Chikamatsu, Tsukasa Katayama, Yasushi Hirose, Isao Harayama, Daiichiro Sekiba, Eiji Ikenaga, Makoto Minohara, Hiroshi Kumigashira, Tetsuya Hasegawa
Perovskite nickel oxides are of fundamental as well as technological interest because they show large resistance modulation associated with phase transition as a function of the temperature and chemical composition. Here, the effects of fluorine doping in perovskite nickelate NdNiO3 epitaxial thin films are investigated through a low-temperature reaction with polyvinylidene fluoride as the fluorine source. The fluorine content in the fluorinated NdNiO3-xFx films is controlled with precision by varying the reaction time...
March 16, 2017: ACS Applied Materials & Interfaces
Marie-Christine Zdora, Joan Vila-Comamala, Georg Schulz, Anna Khimchenko, Alexander Hipp, Andrew C Cook, Daniel Dilg, Christian David, Christian Grünzweig, Christoph Rau, Pierre Thibault, Irene Zanette
The high-throughput 3D visualisation of biological specimens is essential for studying diseases and developmental disorders. It requires imaging methods that deliver high-contrast, high-resolution volumetric information at short sample preparation and acquisition times. Here we show that X-ray phase-contrast tomography using a single grating can provide a powerful alternative to commonly employed techniques, such as high-resolution episcopic microscopy (HREM). We present the phase tomography of a mouse embryo in paraffin obtained with an X-ray single-grating interferometer at I13-2 Beamline at Diamond Light Source and discuss the results in comparison with HREM measurements...
February 1, 2017: Biomedical Optics Express
Eduardo Coello, Jonathan I Sperl, Dirk Bequé, Tobias Benz, Kai Scherer, Julia Herzen, Anikó Sztrókay-Gaul, Karin Hellerhoff, Franz Pfeiffer, Cristina Cozzini, Susanne Grandl
X-Ray Phase-Contrast (XPC) imaging is a novel technology with a great potential for applications in clinical practice, with breast imaging being of special interest. This work introduces an intuitive methodology to combine and visualize relevant diagnostic features, present in the X-ray attenuation, phase shift and scattering information retrieved in XPC imaging, using a Fourier domain fusion algorithm. The method allows to present complementary information from the three acquired signals in one single image, minimizing the noise component and maintaining visual similarity to a conventional X-ray image, but with noticeable enhancement in diagnostic features, details and resolution...
April 2017: European Journal of Radiology
Edward B Trigg, Mark J Stevens, Karen I Winey
Precise control over polymer architecture unlocks the potential for engineered self-assembled crystal structures with useful features on the nanometer length scale. Here we elucidate the structure of the ordered phase of a semicrystalline, functional polyethylene having a precise linear architecture, namely, pendant carboxylic acid groups precisely every 21st backbone carbon atom. By comparing the results of atomistic molecular dynamics simulations with experimental X-ray scattering and Raman spectroscopy data, we find that the polymer chains are folded in a hairpin manner near each carboxylic acid group, giving rise to multiple embedded layers of functional groups that have an interlayer distance of 2...
March 6, 2017: Journal of the American Chemical Society
Lin Zhou, Xuan Zheng, Ping-Ping Shi, Zainab Zafar, Heng-Yun Ye, Da-Wei Fu, Qiong Ye
A new perovskite-like inorganic-organic hybrid compound [Et3(n-Pr)P][Cd(dca)3] (1) (where [Et3(n-Pr)P](+) is the propyltriethylphosphonium cation and dca is a dicyanamide ligand) was discovered to undergo three reversible phase transitions at 270 K (T1), 386 K (T2), and 415 K (T3), respectively. The variable-temperature single-crystal X-ray structural analyses reveal that these sequential phase transitions originate from the deformations of the [Cd(dca)3](-) frameworks and the concomitant reorientations of the [Et3(n-Pr)P](+) guest cations...
March 6, 2017: Inorganic Chemistry
Dina M Drennan, Robert Almstrand, Jeffrey Ladderud, Ilsu Lee, Lee Landkamer, Linda Figueroa, Jonathan O Sharp
Sulfate-reducing bioreactors (SRBRs) represent a passive, sustainable, and long-term option for mitigating mining influenced water (MIW) during release. Here we investigate spatial zinc precipitation profiles as influenced by substrate differentiation, inorganic ligand availability (inorganic carbon and sulfide), and microbial community structure in pilot-scale SRBR columns fed with sulfate and zinc-rich MIW. Through a combination of aqueous sampling, geochemical digests, electron microscopy and energy-dispersive x-ray spectroscopy, we were able to delineate zones of enhanced zinc removal, identify precipitates of varying stability, and discern the temporal and spatial evolution of zinc, sulfur, and calcium associations...
February 20, 2017: Water Research
Qianyue Sun, Yuhui Yang, Wenjing Luo, Jinghui Zhao, Yanmin Zhou
A calcium phosphate (CaP) coating on titanium surface enhances its biocompatibility, thus facilitating osteoconduction and osteoinduction with the inorganic phase of the human bone. Electrochemical deposition has been suggested as an effective means of fabricating CaP coatings on porous surface. The purpose of this study was to develop CaP coatings on a direct laser metal forming implant using electrochemical deposition and to investigate the effect of electrolytic concentration on the coating's morphology and structure by X-ray diffraction, scanning electron microscopy, water contact angle analysis, and Fourier transform infrared spectroscopy...
2017: International Journal of Analytical Chemistry
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