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X ray phase contrast

L Krishna Bharat, G Seeta Rama Raju, Jae Su Yu
We report the synthesis of spherical-shaped rare-earth (Eu(3+) and Tb(3+)) ions doped CaMoO4 nanoparticles in double solvents (IPA and H2O) with the help of autoclave. The X-ray diffraction patterns well match with the standard values and confirm the crystallization in a tetragonal phase with an I41/a (88) space group. The luminescence spectra exhibit the strong red and green emissions from Eu(3+) and Tb(3+) ions doped samples, respectively. The X-ray photoelectron spectroscopy results show the oxidation states of all the elements present in the sample...
September 14, 2017: Scientific Reports
Bram Trachet, Lydia Aslanidou, Alessandra Piersigilli, Rodrigo A Fraga-Silva, Jessica Sordet-Dessimoz, Pablo Villanueva-Perez, Marco F M Stampanoni, Nikolaos Stergiopulos, Patrick Segers
Aims: Angiotensin II-infused ApoE-/- mice are a popular mouse model for preclinical aneurysm research. Here, we provide insight in the often-reported but seldom-explained variability in shape of dissecting aneurysms in these mice. Methods and results: N = 45 excised aortas were scanned ex vivo with phase-contrast X-ray tomographic microscopy. Micro-ruptures were detected near the ostium of celiac and mesenteric arteries in 8/11 mice that were sacrificed after 3 days of angiotensin II-infusion...
August 1, 2017: Cardiovascular Research
Victoria M Steffes, Meena M Murali, Yoonsang Park, Bretton J Fletcher, Kai K Ewert, Cyrus R Safinya
Lipid-based particles are used worldwide in clinical trials as carriers of hydrophobic paclitaxel (PTXL) for cancer chemotherapy, albeit with little improvement over the standard-of-care. Improving efficacy requires an understanding of intramembrane interactions between PTXL and lipids to enhance PTXL solubilization and suppress PTXL phase separation into crystals. We studied the solubility of PTXL in cationic liposomes (CLs) composed of positively charged 2,3-dioleyloxypropyltrimethylammonium chloride (DOTAP) and neutral 1,2-dioleoyl-sn-glycero-3-phosphatidylcholine (DOPC) as a function of PTXL membrane content and its relation to efficacy...
August 17, 2017: Biomaterials
Huiqiang Liu, Chuanshan Zhang, Xiaoxi Fan, Yingni Duan, Tiqiao Xiao, Guohao Du, Yanan Fu, Haigang Liu, Hao Wen
Propagation-based phase-contrast computed micro-tomography (PPCT) dominates the non-destructive, three-dimensional inner-structure measurement in synchrotron-based biomedical research due to its simple experimental setup. To quantitatively visualize tiny density variations in soft tissues and organs closely related to early pathological morphology, an experimental study of synchrotron-based X-ray PPCT combined with generalized phase and attenuation duality (PAD) phase retrieval was implemented with the hepatic echinococcosis (HE) infection rat model at different stages...
2017: PloS One
Tianding Wu, Yong Cao, Shuangfei Ni, Zixiang Luo, Liyuan Jiang, Hongbin Lu, Jianzhong Hu
STUDY DESIGN: An advanced imaging of vasculature with synchrotron radiation X-ray in a rat model. OBJECTIVE: To develop the potential for quantitative assessment of vessel network from 2D to 3D visualization by synchrotron radiation X-ray phase contrast tomography (XPCT) in rat spinal cord model. SUMMARY OF BACKGROUND DATA: Investigation of microvasculature contributes to the understanding of pathological development of spinal cord injury...
September 6, 2017: Spine
Erika M Dematteis, Eugenio R Pinatel, Marta Corno, Torben R Jensen, Marcello Baricco
A combination of experimental and computational techniques has been used to fully describe the thermodynamic properties and phase diagrams of the LiBH4-NaBH4-KBH4 system. The Calphad method was used to assess the thermodynamic properties of LiBH4-NaBH4, LiBH4-KBH4, and NaBH4-KBH4 binary systems and to extend the investigation to the LiBH4-NaBH4-KBH4 ternary system. Samples with various compositions in the ternary system were synthesised, both by ball milling and manual mixing of the parent borohydrides, and their thermal stability has been studied using in situ synchrotron radiation X-ray diffraction as a function of temperature and using differential scanning calorimetry...
September 20, 2017: Physical Chemistry Chemical Physics: PCCP
Mathias Marschner, Lorenz Birnbacher, Marian Willner, Michael Chabior, Julia Herzen, Peter B Noël, Franz Pfeiffer
Phase-contrast x-ray computed tomography (PCCT) is currently investigated as an interesting extension of conventional CT, providing high soft-tissue contrast even if examining weakly absorbing specimen. Until now, the potential for dose reduction was thought to be limited compared to attenuation CT, since meaningful phase retrieval fails for scans with very low photon counts when using the conventional phase retrieval method via phase stepping. In this work, we examine the statistical behaviour of the reverse projection method, an alternative phase retrieval approach and compare the results to the conventional phase retrieval technique...
2017: PloS One
Gabriela Kovácsová, Marie Luise Grünbein, Marco Kloos, Thomas R M Barends, Ramona Schlesinger, Joachim Heberle, Wolfgang Kabsch, Robert L Shoeman, R Bruce Doak, Ilme Schlichting
Serial (femtosecond) crystallography at synchrotron and X-ray free-electron laser (XFEL) sources distributes the absorbed radiation dose over all crystals used for data collection and therefore allows measurement of radiation damage prone systems, including the use of microcrystals for room-temperature measurements. Serial crystallography relies on fast and efficient exchange of crystals upon X-ray exposure, which can be achieved using a variety of methods, including various injection techniques. The latter vary significantly in their flow rates - gas dynamic virtual nozzle based injectors provide very thin fast-flowing jets, whereas high-viscosity extrusion injectors produce much thicker streams with flow rates two to three orders of magnitude lower...
July 1, 2017: IUCrJ
Michele C Darrow, Imanol Luengo, Mark Basham, Matthew C Spink, Sarah Irvine, Andrew P French, Alun W Ashton, Elizabeth M H Duke
Segmentation is the process of isolating specific regions or objects within an imaged volume, so that further study can be undertaken on these areas of interest. When considering the analysis of complex biological systems, the segmentation of three-dimensional image data is a time consuming and labor intensive step. With the increased availability of many imaging modalities and with automated data collection schemes, this poses an increased challenge for the modern experimental biologist to move from data to knowledge...
August 23, 2017: Journal of Visualized Experiments: JoVE
S Carlotto, L Floreano, A Cossaro, M Dominguez, M Rancan, M Sambi, M Casarin
The occupied and unoccupied electronic structures of three high spin TM(acac)3 (TM = Cr, Mn, and Fe) complexes (I, II, and III, respectively) were studied by revisiting their literature vapour-phase He(i) and, when available, He(ii) photoemission (PE) spectra and by means of original near-edge X-ray absorption fine structure (NEXAFS) spectroscopic data recorded at the O K-edge ((O)K-edge) and TM L2,3-edges ((TM)L2,3-edges). The assignments of the vapour-phase He(i)/He(ii) PE spectra were guided by the results of spin-unrestricted non-relativistic Slater transition state calculations, while the (O)K-edge and (TM)L2,3-edge spectroscopic pieces of evidence were analysed by exploiting the results of spin-unrestricted scalar-relativistic time-dependent density functional theory (DFT) and DFT/ROCIS calculations, respectively...
September 20, 2017: Physical Chemistry Chemical Physics: PCCP
Ronghui Luo, Zhao Wu, Ying Xiong, Chenxi Wei, Xiaobo Zhang, Renfang Hu, Lei Wang, Liang Guo, Gang Liu, Yangchao Tian
Grating-based X-ray phase contrast imaging technology is one of the most potential imaging methods in real applications. It can be classified into two categories: interferometry and non-interferometric imaging. The non-interferometric grating-based X-ray phase contrast imaging (NIGPCI) instrument has a great advantage in the forthcoming commercial applications for the flexible system design and the use of large periodic gratings. The performance of the NIGPCI instrument depends on its angular sensitivity to a great extent...
August 2017: Review of Scientific Instruments
Shanhong Wan, Anh Kiet Tieu, Yana Xia, Liping Wang, Dongshan Li, Guangan Zhang, Hongtao Zhu, Bach H Tran, David R G Mitchell
Understanding how an adaptive integrated interface between lubricant additives and solid contacts works will enable improving the wear and friction of moving engine components. This work represents the comprehensive characterization of compositional and structural orientation at the sliding interface from the perspective of surface/interface tribochemistry. The integrated interface of a lubricant additive-solid resulting from the friction testing of Graphite-like carbon (GLC) and PVD-CrN coated rings sliding against cast iron under boundary lubrication was studied...
August 30, 2017: Scientific Reports
Dongjiang Ji, Gangrong Qu, Chunhong Hu, Yuqing Zhao, Xiaodong Chen
In practice, mis-calibrated detector pixels give rise to wide and faint ring artifacts in the reconstruction image of the In-line phase-contrast computed tomography (IL-PC-CT). Ring artifacts correction is essential in IL-PC-CT. In this study, a novel method of wide and faint ring artifacts correction was presented based on combining TV-L1 model with guided image filtering (GIF) in the reconstruction image domain. The new correction method includes two main steps namely, the GIF step and the TV-L1 step. To validate the performance of this method, simulation data and real experimental synchrotron data are provided...
August 24, 2017: Journal of X-ray Science and Technology
Chi Wang, Ting-Ting Hsiue
Through single-tube electrospinning, the biodegradable core-shell fibers of poly(3-hydroxybutyrate) (PHB) and poly(d,l-lactic acid) (PDLLA) were obtained from blend solutions with different compositions at a total polymer concentration of 7 wt %. Regardless whether PHB is the major or minor component (PHB/PDLLA = 90/10, 75/25, 50/50, and 25/75 wt. ratio), these phase-separated solutions all yielded core-shell fibers with PHB as core and PDLLA as shell. A new scenario of core-shell fiber formation was proposed on the basis of the relative magnitude of the intrinsic relaxation rate of fluids and external extension rate during electrospinning...
August 30, 2017: Biomacromolecules
Susan Notohamiprodjo, Nicole Webber, Lorenz Birnbacher, Marian Willner, Manuel Viermetz, Julia Herzen, Mathias Marschner, Doris Mayr, Harald Bartsch, Tobias Saam, Sigrid Auweter, Franz Pfeiffer, Maximilian F Reiser, Holger Hetterich
OBJECTIVES: Grating-based phase-contrast computed tomography (gb-PCCT) relies on x-ray refraction instead of absorption to generate high-contrast images in biological soft tissue. The aim of this study was to evaluate the potential of gb-PCCT for the depiction of structural changes in heart disease. MATERIALS AND METHODS: Four human heart specimens from patients with hypertensive disease, ischemic disease, dilated heart disease, and cardiac lipomatosis were examined...
August 25, 2017: Investigative Radiology
Marie E Roy, Leo A Whiteside, Arun M Sebastian
BACKGROUND: The degradation of ceramic femoral heads made of yttria-stabilized zirconia (Y-TZP) because of tetragonal-to-monoclinic phase transformation in vivo is well-described, whereas magnesia-stabilized zirconia (Mg-PSZ) ceramics resist phase transformation in a warm aqueous environment. The purpose of this study was to evaluate phase transformation, changes in surface topography, and roughness parameters, including changes in surface polarity and abrasiveness, among retrieved zirconia femoral heads...
July 25, 2017: Journal of Arthroplasty
Alessia Nava, Alfredo Coppa, Donato Coppola, Lucia Mancini, Diego Dreossi, Franco Zanini, Federico Bernardini, Claudio Tuniz, Luca Bondioli
The fetal remains from the Ostuni 1 burial (Italy, ca 27 ka) represent a unique opportunity to explore the prenatal biological parameters, and to reconstruct the possible patho-biography, of a fetus (and its mother) in an Upper Paleolithic context. Phase-contrast synchrotron X-ray microtomography imaging of two deciduous tooth crowns and microfocus CT measurements of the right hemimandible of the Ostuni 1b fetus were performed at the SYRMEP beamline and at the TomoLab station of the Elettra - Sincrotrone laboratory (Trieste, Italy) in order to refine age at death and to report the enamel developmental history and dental tissue volumes for this fetal individual...
August 25, 2017: Scientific Reports
Roy l'Abee, Martin van Duin, Han Goossens
The micromechanical deformation mechanisms of sub-μm thermoplastic vulcanizates (TPVs) based on poly(ε-caprolactone) (PCL) and cross-linked methacrylate rubbers were studied by time-resolved small-angle X-ray scattering (SAXS) and wide-angle X-ray diffraction (WAXD) measurements in order to better understand the underlying deformation mechanisms responsible for the high elongation at break and good elastic recovery of sub-μm TPVs. It is demonstrated that, in contrast to neat PCL, the interlamellar void formation in the PCL matrix and subsequent coalescence of voids is suppressed by the presence of the rubber (nano)particles in these TPVs...
August 24, 2017: Soft Matter
Tao Chen, Sha Yang, Jinsong Chai, Yongbo Song, Jiqiang Fan, Bo Rao, Hongting Sheng, Haizhu Yu, Manzhou Zhu
We report the first noble metal nanocluster with a formula of Au4Ag13(DPPM)3(SR)9 exhibiting crystallization-induced emission enhancement (CIEE), where DPPM denotes bis(diphenylphosphino)methane and HSR denotes 2,5-dimethylbenzenethiol. The precise atomic structure is determined by x-ray crystallography. The crystalline state of Au4Ag13 shows strong luminescence at 695 nm, in striking contrast to the weak emission of the amorphous state and hardly any emission in solution phase. The structural analysis and the density functional theory calculations imply that the compact C-H⋯π interactions significantly restrict the intramolecular rotations and vibrations and thus considerably enhance the radiative transitions in the crystalline state...
August 2017: Science Advances
Di Wu, Molly Donovan Wong, Kai Yang, Aimin Yan, Yuhua Li, Laurie Fajardo, Bin Zheng, Xizeng Wu, Hong Liu
The ability of microbubbles to benefit the imaging quality of high-energy in-line phase contrast as compared with conventional low-energy contact mode radiography was investigated. The study was conducted by comparing in-line phase contrast imaging with conventional contact-mode projection imaging under the same dose delivered to a phantom. A custom designed phantom was employed to simulate a segment of human blood vessel injected with microbubble suspensions. The microbubbles were suspended in deionized water to obtain different volume concentrations...
August 21, 2017: IEEE Transactions on Bio-medical Engineering
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