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https://www.readbyqxmd.com/read/28228039/cell-quintupling-structural-phase-transition-in-a-molecular-crystal-bis-trans-4-butylcyclohexyl-methanol
#1
Kazuya Saito, Takaaki Ikeda, Yasuhisa Yamamura, Hideki Saitoh, Mafumi Hishida, Yutaro Kobayashi, Takeshi Fujita, Junji Ichikawa
A structural phase transition at 151.6 K of the title compound [bis(trans-4-butylcyclohexyl)methanol] is examined by X-ray diffraction crystallography, Fourier-transform infrared spectroscopy, and adiabatic calorimetry. A general consideration on possible superstructures indicates that a single modulation wave is sufficient to drive this cell-quintupling transition. The entropy of transition determined calorimetrically indicates that two conformations are dominant in the room-temperature phase in contrast to the fivefold disorder expected from the structure of the low-temperature phase...
February 21, 2017: Journal of Chemical Physics
https://www.readbyqxmd.com/read/28226214/selective-encaging-of-n2o-in-n2o-n2-binary-gas-hydrates-via-hydrate-based-gas-separation
#2
Youjeong Yang, Donghoon Shin, Seunghyun Choi, Yesol Woo, Jong-Won Lee, Dongseon Kim, Hee-Young Shin, Minjun Cha, Ji-Ho Yoon
The crystal structure and guest inclusion behaviors of nitrous oxide-nitrogen (N2O-N2) binary gas hydrates formed from N2O/N2 gas mixtures are determined through spectroscopic analysis. Powder X-ray diffraction results indicate that the crystal structure of all the N2O-N2 binary gas hydrates is identified as the structure I (sI) hydrate. Raman spectra for N2O-N2 binary gas hydrate formed from N2O/N2 (80/20, 60/40, 40/60 mol %) gas mixtures reveal that N2O molecules occupy both large and small cages of the sI hydrate...
February 22, 2017: Environmental Science & Technology
https://www.readbyqxmd.com/read/28209631/hdpscs-fabricate-a-vascularised-woven-bone-tissue-a-new-tool-in-bone-tissue-engineering
#3
Francesca Paino, Marcella La Noce, Alessandra Giuliani, Alfredo De Rosa, Serena Mazzoni, Luigi Laino, Evzen Amler, Gianpaolo Papaccio, Vincenzo Desiderio, Virginia Tirino
Human dental pulp stem cells (hDPSCs) are mesenchymal stem cells successfully used in human bone tissue engineering. To better establish if these cells can lead to a bone tissue ready to be grafted, we checked DPSCs for their osteogenic and angiogenic differentiation capabilities with the specific aim to obtain a new tool for bone transplantation. Therefore, hDPSCs were specifically selected from the stromal-vascular dental pulp fraction, using appropriate markers and cultured. Growth curves, expression of bone-related markers, calcification, angiogenesis as well as in vivo transplantation assay were performed...
February 16, 2017: Clinical Science (1979-)
https://www.readbyqxmd.com/read/28181677/application-of-sensitive-high-resolution-imaging-at-a-commercial-lab-based-x-ray-micro-ct-system-using-propagation-based-phase-retrieval
#4
P Bidola, K Morgan, M Willner, A Fehringer, S Allner, F Prade, F Pfeiffer, K Achterhold
Several dedicated commercial lab-based micro-computed tomography (μCT) systems exist, which provide high-resolution images of samples, with the capability to also deliver in-line phase contrast. X-ray phase contrast is particularly beneficial when visualizing very small features and weakly absorbing samples. The raw measured projections will include both phase and absorption effects. Extending our previous work that addressed the optimization of experimental conditions at the commercial ZEISS Xradia 500 Versa system, single-distance phase-contrast imaging is demonstrated on complex biological and material samples...
February 9, 2017: Journal of Microscopy
https://www.readbyqxmd.com/read/28165065/interplay-between-the-static-ordering-and-dynamical-heterogeneities-determining-the-dynamics-of-rotation-and-ordinary-liquid-phases-in-1-6-anhydro-%C3%AE-d-glucose
#5
O Madejczyk, K Kaminski, E Kaminska, K Jurkiewicz, M Tarnacka, A Burian, M Paluch
In this letter, we reported thorough the structural and molecular dynamics studies on 1,6-anhydro-β-D-glucose, the second compound reported so far that is capable to form rotator and supercooled liquid phases. In contrast to the data presented for ethanol, temperature dependences of structural dynamics in both phases are very comparable. On the other hand, X ray measurements revealed unusually long range ordering/correlations between molecules in the ODIC (d ≈ 95 Å) and supercooled phases (d ≈ 30-40 Å) of this carbohydrate...
February 6, 2017: Scientific Reports
https://www.readbyqxmd.com/read/28159991/x-ray-phase-contrast-tomography-opens-new-era-for-cardiovascular-research
#6
Takuro Tsukube, Masato Hoshino, Naoto Yagi
No abstract text is available yet for this article.
February 4, 2017: European Heart Journal Cardiovascular Imaging
https://www.readbyqxmd.com/read/28158943/nuclear-dynamical-correlation-effects-in-x-ray-spectroscopy-from-a-theoretical-time-domain-perspective
#7
Sven Karsten, Sergei D Ivanov, Saadullah G Aziz, Sergey I Bokarev, Oliver Kühn
To date X-ray spectroscopy has become a routine tool that can reveal highly local and element-specific information on the electronic structure of atoms in complex environments. Here, we focus on nuclear dynamical correlation effects in X-ray spectra and develop a rigorous time-correlation function method employing ground state classical molecular dynamics simulations. The importance of nuclear correlation phenomena is demonstrated by comparison against the results from the conventional sampling approach performed on the same dataset for gas phase water...
February 3, 2017: Journal of Physical Chemistry Letters
https://www.readbyqxmd.com/read/28158042/high-speed-two-dimensional-synchrotron-white-beam-x-ray-radiography-of-spray-breakup-and-atomization
#8
Benjamin R Halls, Christopher D Radke, Benjamin J Reuter, Alan L Kastengren, James R Gord, Terrence R Meyer
High-speed, two-dimensional synchrotron x-ray radiography and phase-contrast imaging are demonstrated in propulsion sprays. Measurements are performed at the 7-BM beamline at the Advanced Photon Source user facility at Argonne National Laboratory using a recently developed broadband x-ray white beam. This novel enhancement allows for high speed, high fidelity x-ray imaging for the community at large. Quantitative path-integrated liquid distributions and spatio-temporal dynamics of the sprays were imaged with a LuAG:Ce scintillator optically coupled to a high-speed CMOS camera...
January 23, 2017: Optics Express
https://www.readbyqxmd.com/read/28147659/large-field-of-view-tiled-grating-structures-for-x-ray-phase-contrast-imaging
#9
Tobias J Schröter, Frieder J Koch, Pascal Meyer, Danays Kunka, Jan Meiser, Konstantin Willer, Lukas Gromann, Fabio De Marco, Julia Herzen, Peter Noel, Andre Yaroshenko, Andreas Hofmann, Franz Pfeiffer, Jürgen Mohr
X-ray grating-based interferometry promises unique new diagnostic possibilities in medical imaging and materials analysis. To transfer this method from scientific laboratories or small-animal applications to clinical radiography applications, compact setups with a large field of view (FoV) are required. Currently the FoV is limited by the grating area, which is restricted due to the complex manufacturing process. One possibility to increase the FoV is tiling individual grating tiles to create one large area grating mounted on a carrier substrate...
January 2017: Review of Scientific Instruments
https://www.readbyqxmd.com/read/28146542/single-shot-edge-illumination-x-ray-phase-contrast-tomography-enabled-by-joint-image-reconstruction
#10
Yujia Chen, Huifeng Guan, Charlotte K Hagen, Alessandro Olivo, Mark A Anastasio
Edge illumination x-ray phase-contrast tomography (EIXPCT) is an emerging x-ray phase-contrast tomography technique for reconstructing the complex-valued x-ray refractive index distribution of an object. Conventional image reconstruction approaches for EIXPCT require multiple images to be acquired at each tomographic view angle. This contributes to prolonged data-acquisition times and elevated radiation doses, which can hinder in vivo applications. In this work, a new "single-shot" method is proposed for joint reconstruction (JR) of the real and imaginary-valued components of the refractive index distribution from a tomographic data set that contains only a single image acquired at each view angle...
February 1, 2017: Optics Letters
https://www.readbyqxmd.com/read/28140377/optimization-of-propagation-based-x-ray-phase-contrast-tomography-for-breast-cancer-imaging
#11
Patrycja Baran, Serena Pacile, Yakov Nesterets, Sheridan Mayo, Christian Dullin, Diego Dreossi, Fulvia Arfelli, Darren Thompson, Darren Lockie, Mikkaela McCormack, Seyedamir Taba, Francesco Brun, Maurizio Pinamonti, Carolyn Nickson, Christopher Hall, Matthew Dimmock, Fabrizio Zanconati, Marian Cholewa, Harry Quiney, Patrick Brennan, Giuliana Tromba, Tim E Gureyev
The aim of this study was to optimise the experimental protocol and data analysis for in-vivo breast cancer X-ray imaging. Results are presented of the experiment at the SYRMEP beamline of Elettra Synchrotron using the propagation-based phase-contrast mammographic tomography method, which incorporates not only absorption, but also X-ray phase information. In this study the images of breast tissue samples, of a size corresponding to a full human breast, with radiologically acceptable X-ray doses were obtained, and the degree of improvement of the image quality (from the diagnostic point of view) achievable using propagation-based phase-contrast image acquisition protocols with proper incorporation of X-ray phase retrieval into the reconstruction pipeline was investigated...
January 31, 2017: Physics in Medicine and Biology
https://www.readbyqxmd.com/read/28128834/mono-and-bimetallic-manganese-carbonyl-complexes-and-clusters-bearing-imidazol-in-ium-2-dithiocarboxylate-ligands
#12
Tomás F Beltrán, Guillermo Zaragoza, Lionel Delaude
Five complexes with the generic formula fac-[MnBr(CO)3(S2C·NHC)] were obtained by reacting [MnBr(CO)5] with a set of representative imidazol(in)ium-2-dithiocarboxylate zwitterions. These ligands are the adducts of N-heterocyclic carbenes (NHCs) and carbon disulfide. The mononuclear Mn(i) derivatives were coupled with Na[Mn(CO)5] to afford bimetallic [Mn2(CO)6(S2C·NHC)] clusters. Yet, the most convenient strategy to access these dinuclear Mn(0) products implied a direct carbonyl substitution from the [Mn2(CO)10] dimer...
January 27, 2017: Dalton Transactions: An International Journal of Inorganic Chemistry
https://www.readbyqxmd.com/read/28122521/neovascularization-of-hepatocellular-carcinoma-in-a-nude-mouse-orthotopic-liver-cancer-model-a-morphological-study-using-x-ray-in-line-phase-contrast-imaging
#13
Beilei Li, Yiqiu Zhang, Weizhong Wu, Guohao Du, Liang Cai, Hongcheng Shi, Shaoliang Chen
BACKGROUND: This study aimed to determine whether synchrotron radiation (SR)-based X-ray in-line phase-contrast imaging (IL-PCI) can be used to investigate the morphological characteristics of tumor neovascularization in a liver xenograft animal model. METHODS: A human hepatocellular carcinoma HCCLM3 xenograft model was established in nude mice. Xenografts were sampled each week for 4 weeks and fixed to analyze tissue characteristics and neovascularization using SR-based X-ray in-line phase contrast computed tomography (IL-XPCT) without any contrast agent...
January 25, 2017: BMC Cancer
https://www.readbyqxmd.com/read/28118061/a-comparison-of-radiation-induced-mitochondrial-damage-between-neural-progenitor-stem-cells-and-differentiated-cells
#14
Tsutomu Shimura, Megumi Sasatani, Hidehiko Kawai, Kenji Kamiya, Junya Kobayashi, Kenshi Komatsu, Naoki Kunugita
Mitochondria play a key role in maintaining cellular homeostasis during stress responses, and mitochondrial dysfunction contributes to carcinogenesis, aging, and neurological disease. We here investigated ionizing radiation (IR)-induced mitochondrial damage in human neural progenitor stem cells (NSCs), their differentiated counterparts and human normal fibroblasts. Long-term fractionated radiation (FR) with low doses of X-rays for 31 days enhanced mitochondrial activity as evident by elevated mitochondrial membrane potential (ΔΨm) and mitochondrial complex IV (cytochrome c oxidase) activity to fill the energy demands for the chronic DNA damage response in differentiated cells...
January 24, 2017: Cell Cycle
https://www.readbyqxmd.com/read/28112212/quantitative-3d-investigation-of-neuronal-network-in-mouse-spinal-cord-model
#15
I Bukreeva, G Campi, M Fratini, R Spanò, D Bucci, G Battaglia, F Giove, A Bravin, A Uccelli, C Venturi, M Mastrogiacomo, A Cedola
The investigation of the neuronal network in mouse spinal cord models represents the basis for the research on neurodegenerative diseases. In this framework, the quantitative analysis of the single elements in different districts is a crucial task. However, conventional 3D imaging techniques do not have enough spatial resolution and contrast to allow for a quantitative investigation of the neuronal network. Exploiting the high coherence and the high flux of synchrotron sources, X-ray Phase-Contrast multiscale-Tomography allows for the 3D investigation of the neuronal microanatomy without any aggressive sample preparation or sectioning...
January 23, 2017: Scientific Reports
https://www.readbyqxmd.com/read/28109750/phytosphingosine-sphingosine-and-dihydrosphingosine-ceramides-in-model-skin-lipid-membranes-permeability-and-biophysics
#16
Barbora Školová, Andrej Kováčik, Ondřej Tesař, Lukáš Opálka, Kateřina Vávrová
Ceramides based on phytosphingosine, sphingosine and dihydrosphingosine are essential constituents of the skin lipid barrier that protects the body from excessive water loss. The roles of the individual ceramide subclasses in regulating skin permeability and the reasons for C4-hydroxylation of these sphingolipids are not completely understood. We investigated the chain length-dependent effects of dihydroceramides, sphingosine ceramides (with C4-unsaturation) and phytoceramides (with C4-hydroxyl) on the permeability, lipid organization and thermotropic behavior of model stratum corneum lipid membranes composed of ceramide/lignoceric acid/cholesterol/cholesteryl sulfate...
January 18, 2017: Biochimica et Biophysica Acta
https://www.readbyqxmd.com/read/28102690/ph-sensitive-adsorption-behavior-of-polymer-particles-at-the-air-water-interface
#17
Syuji Fujii, Emiko Mouri, Ko Akiyama, Saori Nakayama, Kyohei Uda, Yoshinobu Nakamura, Hideki Matsuoka
pH-Sensitive adsorption of polymer particles bearing poly[2-(dimethylamino)ethyl methacrylate] hairs at the air-water interface was investigated using a surface tensiometer, a Langmuir-Blodgett trough, and an X-ray reflectometer. We clarified that the particles are adsorbed at the interface at basic pH; by contrast, at acidic pH, only a small number of particles are adsorbed, whereas the majority are dispersed in the water phase. X-ray reflectometry analysis revealed that a particle monolayer was formed at the air-water interface, which was packed densely under increasing surface pressure, as determined by the electron density profile change...
February 3, 2017: Langmuir: the ACS Journal of Surfaces and Colloids
https://www.readbyqxmd.com/read/28097509/revealing-pmdi-spray-initial-conditions-flashing-atomisation-and-the-effect-of-ethanol
#18
Nicholas Mason-Smith, Daniel J Duke, Alan L Kastengren, Daniela Traini, Paul M Young, Yang Chen, David A Lewis, Daniel Edgington-Mitchell, Damon Honnery
PURPOSE: Sprays from pressurised metered-dose inhalers are produced by a transient discharge of a multiphase mixture. Small length and short time scales have made the investigation of the governing processes difficult. Consequently, a deep understanding of the physical processes that govern atomisation and drug particle formation has been elusive. METHODS: X-ray phase contrast imaging and quantitative radiography were used to reveal the internal flow structure and measure the time-variant nozzle exit mass density of 50 µL metered sprays of HFA134a, with and without ethanol cosolvent...
January 17, 2017: Pharmaceutical Research
https://www.readbyqxmd.com/read/28095993/evaluation-of-the-short-term-fate-and-transport-of-chemicals-of-emerging-concern-during-soil-aquifer-treatment-using-select-transformation-products-as-intrinsic-redox-sensitive-tracers
#19
Meriam Muntau, Manoj Schulz, Kevin S Jewell, Nina Hermes, Uwe Hübner, Thomas Ternes, Jörg E Drewes
In this study, known products from oxic transformation of the X-ray contrast medium iopromide were introduced for the first time as intrinsic tracer for in situ characterization of the transition zone between oxic and suboxic conditions during the initial phase of soil-aquifer treatment (SAT). Two wet-dry cycles of a full-scale infiltration basin were monitored to characterize hydraulic retention times, redox conditions, removal of bulk organic parameters and the fate of chemicals of emerging concern (CECs)...
January 14, 2017: Science of the Total Environment
https://www.readbyqxmd.com/read/28079701/ex-vivo-assessment-of-coronary-atherosclerotic-plaque-by-grating-based-phase-contrast-computed-tomography-correlation-with-optical-coherence-tomography
#20
Christopher Habbel, Holger Hetterich, Marian Willner, Julia Herzen, Kristin Steigerwald, Sigrid Auweter, Ulrich Schüller, Jörg Hausleiter, Steffen Massberg, Maximilian Reiser, Franz Pfeiffer, Tobias Saam, Fabian Bamberg
OBJECTIVES: The aim of this study was to determine the diagnostic accuracy of grating-based phase-contrast computed tomography (gb-PCCT) to classify and quantify coronary vessel characteristics in comparison with optical coherence tomography (OCT) and histopathology in an ex vivo setting. MATERIALS AND METHODS: After excision from 5 heart specimens, 15 human coronary arteries underwent gb-PCCT examination using an experimental imaging setup consisting of a rotating molybdenum anode x-ray tube, a Talbot-Lau grating interferometer, and a single photon counting detector...
January 10, 2017: Investigative Radiology
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