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X ray phase contrast

Mohammad Izadifar, Paul Babyn, Michael E Kelly, Dean Chapman, Xiongbiao Chen
Three-dimensional (3D)-bioprinting techniques may be used to modulate electrical/mechanical properties and porosity of hydrogel constructs for fabrication of suitable cardiac implants. Notably, characterization of these properties after implantation remains a challenge, raising the need for the development of novel quantitative imaging techniques for monitoring hydrogel implant behavior in-situ. This study aims to (i) assess the influence of hydrogel bioprinting patterns on electrical/mechanical behavior of cardiac implants based on a 3D-printing technique and (ii) investigate the potential of synchrotron X-ray phase contrast computed tomography (PCI-CT) for estimating elastic modulus/impedance/porosity and microstructural features of 3D-printed cardiac implants in-situ via an ex-vivo study...
July 20, 2017: Tissue Engineering. Part C, Methods
A Cedola, A Bravin, I Bukreeva, M Fratini, A Pacureanu, A Mittone, L Massimi, P Cloetens, P Coan, G Campi, R Spanò, F Brun, V Grigoryev, V Petrosino, C Venturi, M Mastrogiacomo, Nicole Kerlero de Rosbo, A Uccelli
The degenerative effects of multiple sclerosis at the level of the vascular and neuronal networks in the central nervous system are currently the object of intensive investigation. Preclinical studies have demonstrated the efficacy of mesenchymal stem cell (MSC) therapy in experimental autoimmune encephalomyelitis (EAE), the animal model for multiple sclerosis, but the neuropathology of specific lesions in EAE and the effects of MSC treatment are under debate. Because conventional imaging techniques entail protocols that alter the tissues, limiting the reliability of the results, we have used non-invasive X-ray phase-contrast tomography to obtain an unprecedented direct 3D characterization of EAE lesions at micro-to-nano scales, with simultaneous imaging of the vascular and neuronal networks...
July 19, 2017: Scientific Reports
Roberts Blukis, Rudolf Rüffer, Aleksandr I Chumakov, Richard J Harrison
Metallic phases in the Tazewell IIICD iron and Esquel pallasite meteorites were examined using (57)Fe synchrotron Mössbauer spectroscopy. Spatial resolution of ~10-20 μm was achieved, together with high throughput, enabling individual spectra to be recorded in less than 1 h. Spectra were recorded every 5-10 μm, allowing phase fractions and hyperfine parameters to be traced along transects of key microstructural features. The main focus of the study was the transitional region between kamacite and plessite, known as the "cloudy zone...
May 2017: Meteoritics & Planetary Science
Peter Modregger, Matias Kagias, Sarah C Irvine, Rolf Brönnimann, Konstantins Jefimovs, Marco Endrizzi, Alessandro Olivo
Small angle x-ray scattering has been proven to be a valuable method for accessing structural information below the spatial resolution limit implied by direct imaging. Here, we theoretically derive the relation that links the subpixel differential phase signal provided by the sample to the moments of scattering distributions accessible by refraction sensitive x-ray imaging techniques. As an important special case we explain the scatter or dark-field contrast in terms of the sample's phase signal. Further, we establish that, for binary phase objects, the nth moment scales with the difference of the refractive index decrement to the power of n...
June 30, 2017: Physical Review Letters
M Zürch, R Jung, C Späth, J Tümmler, A Guggenmos, D Attwood, U Kleineberg, H Stiel, C Spielmann
Coherent diffraction imaging (CDI) in the extreme ultraviolet has become an important tool for nanoscale investigations. Laser-driven high harmonic generation (HHG) sources allow for lab scale applications such as cancer cell classification and phase-resolved surface studies. HHG sources exhibit excellent coherence but limited photon flux due poor conversion efficiency. In contrast, table-top soft X-ray lasers (SXRL) feature excellent temporal coherence and extraordinary high flux at limited transverse coherence...
July 13, 2017: Scientific Reports
Arokiadhas Iswarya, Baskaralingam Vaseeharan, Mahalingam Anjugam, Balasubramaniem Ashokkumar, Marimuthu Govindarajan, Naiyf S Alharbi, Shine Kadaikunnan, Jamal M Khaled, Giovanni Benelli
The effective treatment of cancer and bacterial pathogens are two key challenges in modern nanomedicine. Here, zinc oxide nanoparticles (ZnO NPs) were fabricated using the crustacean immune molecule β-1, 3- glucan binding protein (Phβ-GBP, 100kDa) purified from the heamolymph of Paratelphusa hydrodromus. β-GBP coated zinc oxide nanoparticles (Phβ-GBP-ZnO NPs) were characterized by UV-vis spectroscopy, X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), and high resolution-transmission electron microscopy (HR-TEM) analyses...
June 24, 2017: Colloids and Surfaces. B, Biointerfaces
Linlin Ye, Yanling Xue, Yudan Wang, Juncheng Qi, Tiqiao Xiao
BACKGROUND: The use of X-ray phase-contrast microtomography for the investigation of Chinese medicinal materials is advantageous for its nondestructive, in situ, and three-dimensional quantitative imaging properties. METHODS: The X-ray phase-contrast microtomography quantitative imaging method was used to investigate the microstructure of ginseng, and the phase-retrieval method is also employed to process the experimental data. Four different ginseng samples were collected and investigated; these were classified according to their species, production area, and sample growth pattern...
July 2017: Journal of Ginseng Research
Iftikhar Khan, Sakib Yousaf, Sneha Subramanian, Mohamed Albed Alhnan, Waqar Ahmed, Abdelbary Elhissi
Formulation effects on the entrapment of beclometasone dipropionate (BDP) in liposomes generated by hydration of proliposomes were studied, using the high-density dispersion medium deuterium oxide in comparison to deionized water (DW). Proliposomes incorporating BDP (2 mol% of the lipid phase consisting of soya phosphatidylcholine (SPC) and cholesterol; 1:1) were manufactured, using lactose monohydrate (LMH), sorbitol or D-mannitol as carbohydrate carriers (1:5 w/w lipid to carrier). Following hydration of proliposomes, separation of BDP-entrapped liposomes from the unentrapped (free) BDP at an optimized centrifugation duration of 90 min and a centrifugation force of 15,500g were identified...
July 11, 2017: AAPS PharmSciTech
Regine Gradl, Martin Dierolf, Lorenz Hehn, Benedikt Günther, Ali Önder Yildirim, Bernhard Gleich, Klaus Achterhold, Franz Pfeiffer, Kaye Susannah Morgan
We demonstrate the applicability of propagation-based X-ray phase-contrast imaging at a laser-assisted compact light source with known phantoms and the lungs and airways of a mouse. The Munich Compact Light Source provides a quasi-monochromatic beam with partial spatial coherence, and high flux relative to other non-synchrotron sources (up to 10(10) ph/s). In our study we observe significant edge-enhancement and quantitative phase-retrieval is successfully performed on the known phantom. Furthermore the images of a small animal show the potential for live bio-imaging research studies that capture biological function using short exposures...
July 7, 2017: Scientific Reports
Xiaoping Li, Ting Wu, Hongxiang Bao, Xianyu Liu, Changlin Xu, Yanan Zhao, Dongying Liu, Hongtao Yu
Rapid urbanization and industrialization may cause increased exposure levels to potential toxic trace elements (PTEs) and associated health risks for population living in cities. The main objectives of this study are to investigate systematically the occurrence, source, fate, and risk of PTE contamination from industrial influence in Baoji urban soil. Seven PTE levels (Pb, Zn, Cu, Cr, V, Sb, and As) were surveyed in 50 composite samples from Baoji urban soil by wavelength dispersive X-ray fluorescence spectrometry...
July 6, 2017: Environmental Science and Pollution Research International
Masayuki Nishi, Yasuhiro Kuwayama, Jun Tsuchiya, Taku Tsuchiya
Water transported into Earth's interior by subduction strongly influences dynamics such as volcanism and plate tectonics. Several recent studies have reported hydrous minerals to be stable at pressure and temperature conditions representative of Earth's deep interior, implying that surface water may be transported as far as the core-mantle boundary. However, the hydrous mineral goethite, α-FeOOH, was recently reported to decompose under the conditions of the middle region of the lower mantle to form FeO2 and release H2, suggesting the upward migration of hydrogen and large fluctuations in the oxygen distribution within the Earth system...
July 13, 2017: Nature
Somayeh Saghamanesh, Seyed Mahmoud-Reza Aghamiri, Alessandro Olivo, Maryam Sadeghilarijani, Hidemi Kato, Alireza Kamali-Asl, Wataru Yashiro
Edge-illumination x-ray phase contrast imaging (EI XPCI) is a non-interferometric phase-sensitive method where two absorption masks are employed. These masks are fabricated through a photolithography process followed by electroplating which is challenging in terms of yield as well as time- and cost-effectiveness. We report on the first implementation of EI XPCI with Pt-based metallic glass masks fabricated by an imprinting method. The new tested alloy exhibits good characteristics including high workability beside high x-ray attenuation...
June 2017: Review of Scientific Instruments
M Endrizzi, F A Vittoria, L Rigon, D Dreossi, F Iacoviello, P R Shearing, A Olivo
We present a multiaperture analyzer setup for performing x-ray phase contrast imaging in planar and three-dimensional modalities. The method is based on strongly structuring the x-ray beam with an amplitude modulator, before it reaches the sample, and on a multiaperture analyzing element before detection. A multislice representation of the sample is used to establish a quantitative relation between projection images and the corresponding three-dimensional distributions, leading to successful tomographic reconstruction...
June 16, 2017: Physical Review Letters
Mohammad Izadifar, Paul Babyn, Dean Chapman, Michael E Kelly, Xiongbiao Chen
Hydrogel-based cardiac tissue engineering offers great promise for myocardial infarction repair. The ability to visualize engineered systems in vivo in animal models is desired to monitor the performance of cardiac constructs. However, due to the low density and weak X-ray attenuation of hydrogels, conventional radiography and micro-computed tomography are unable to visualize the hydrogel cardiac constructs upon their implantation, thus limiting their use in animal systems. This paper presents a study on the optimization of synchrotron X-ray propagation-based phase-contrast imaging computed tomography (PCI-CT) for three-dimensional (3D) visualization and assessment of the hydrogel cardiac patches...
July 1, 2017: Journal of Synchrotron Radiation
Martin Krenkel, Mareike Toepperwien, Frauke Alves, Tim Salditt
X-ray tomography at the level of single biological cells is possible in a low-dose regime, based on full-field holographic recordings, with phase contrast originating from free-space wave propagation. Building upon recent progress in cellular imaging based on the illumination by quasi-point sources provided by X-ray waveguides, here this approach is extended in several ways. First, the phase-retrieval algorithms are extended by an optimized deterministic inversion, based on a multi-distance recording. Second, different advanced forms of iterative phase retrieval are used, operational for single-distance and multi-distance recordings...
July 1, 2017: Acta Crystallographica. Section A, Foundations and Advances
Santanu Kumar Pal, Indu Bala, Santosh Prasad Gupta, Joydip De
Three new oligomeric perylene (PE) tetraester derivatives are reported consisting of a PE-based core attached to which are four pentaalkynylbenzene units via flexible alkyl spacers. These derivatives were investigated for their mesomorphic properties, thermal, photophysical and electrochemical behaviour. Small and wide angle X-ray scattering (SAXS/WAXS) studies were performed to deduce the exact nature of the phases. GISAXS/GIWAXS experiments were carried out on oriented thin films on ITO coated glass substrate and the corresponding electron density maps were derived...
June 28, 2017: Chemistry: a European Journal
Arman Davtyan, Thilo Krause, Dominik Kriegner, Ali Al-Hassan, Danial Bahrami, Seyed Mohammad Mostafavi Kashani, Ryan B Lewis, Hanno Küpers, Abbes Tahraoui, Lutz Geelhaar, Michael Hanke, Steven John Leake, Otmar Loffeld, Ullrich Pietsch
Coherent X-ray diffraction imaging at symmetric hhh Bragg reflections was used to resolve the structure of GaAs/In0.15Ga0.85As/GaAs core-shell-shell nanowires grown on a silicon (111) substrate. Diffraction amplitudes in the vicinity of GaAs 111 and GaAs 333 reflections were used to reconstruct the lost phase information. It is demonstrated that the structure of the core-shell-shell nanowire can be identified by means of phase contrast. Interestingly, it is found that both scattered intensity in the (111) plane and the reconstructed scattering phase show an additional threefold symmetry superimposed with the shape function of the investigated hexagonal nanowires...
June 1, 2017: Journal of Applied Crystallography
Lili Qin, Xinyan Zhao, Jianbo Jian, Yuqing Zhao, Mengyu Sun, Chunhong Hu
X-ray phase-contrast computed tomography (PCCT) can provide excellent image contrast for soft tissues with small density differences, and it is particularly appropriate for three-dimensional (3D) visualization of accurate microstructures inside biological samples. In this study, the morphological structures of proliferative bile ductules (BDs) were visualized without contrast agents via PCCT with liver fibrosis samples induced by bile duct ligation (BDL) in rats. Adult male Sprague-Dawley rats were randomly divided into three groups: sham operation group, 2-week and 6-week post-BDL groups...
June 26, 2017: Scientific Reports
George S K Fung, Luisa Ciuffo, Hiroshi Ashikaga, Katsuyuki Taguchi
PURPOSE: This work concerns computed tomography (CT)-based cardiac functional analysis (CFA) with a reduced radiation dose. As CT-CFA requires images over the entire heartbeat, the scans are often performed at 10-20% of the tube current settings that are typically used for coronary CT angiography. A large image noise then degrades the accuracy of motion estimation. Moreover, even if the scan was performed during the sinus rhythm, the cardiac motion observed in CT images may not be cyclic with patients with atrial fibrillation...
June 22, 2017: Medical Physics
J Stern, T Loerting
The crystallisation behaviour of very high-density amorphous ice (VHDA) and unannealed high-density amorphous ice (uHDA) has been studied in situ by volumetry and ex situ by powder x-ray diffraction in the intermediate pressure range 0.7-1.8 GPa employing different heating rates (0.5, 5 and 30 K min(-1)). This study shows that at pressures >1 GPa the crystallisation behaviour of VHDA and uHDA is basically the same for all heating rates. That is, parallel crystallisation is almost entirely suppressed with mainly ice XII forming...
June 21, 2017: Scientific Reports
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