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https://www.readbyqxmd.com/read/28107207/dynamic-mechanical-interactions-between-neighboring-airspaces-determine-cyclic-opening-and-closure-in-injured-lung
#1
Ludovic Broche, Gaetano Perchiazzi, Liisa Porra, Angela Tannoia, Mariangela Pellegrini, Savino Derosa, Alessandra Sindaco, João Batista Borges, Loïc Degrugilliers, Anders Larsson, Göran Hedenstierna, Anthony S Wexler, Alberto Bravin, Sylvia Verbanck, Bradford J Smith, Jason H T Bates, Sam Bayat
OBJECTIVES: Positive pressure ventilation exposes the lung to mechanical stresses that can exacerbate injury. The exact mechanism of this pathologic process remains elusive. The goal of this study was to describe recruitment/derecruitment at acinar length scales over short-time frames and test the hypothesis that mechanical interdependence between neighboring lung units determines the spatial and temporal distributions of recruitment/derecruitment, using a computational model. DESIGN: Experimental animal study...
January 19, 2017: Critical Care Medicine
https://www.readbyqxmd.com/read/28106517/traditional-invasive-and-synchrotron-based-non-invasive-assessments-of-3d-printed-hybrid-cartilage-constructs
#2
Adeola Deborah Olubamiji, Ning Zhu, Tuanjie Chang, Chijioke Nwankwo, Zohreh Izadifar, Ali Honaramooz, Daniel Chen, B Frank Eames
Three-dimensional (3D)-printed constructs made of polycaprolactone (PCL) and chondrocyte-impregnated alginate hydrogel (hybrid cartilage constructs) mimic the biphasic nature of articular cartilage, offering promise for cartilage tissue engineering (CTE) applications. However, the regulatory pathway for medical device development requires validation of such constructs through in vitro bench tests and in vivo preclinical examinations premarket approval. Furthermore, non-invasive imaging techniques are required for effective evaluation of the progress of these cartilage constructs, especially when implanted in animal models or human subjects...
January 20, 2017: Tissue Engineering. Part C, Methods
https://www.readbyqxmd.com/read/28102667/two-different-structures-of-the-oxygen-evolving-complex-in-the-same-polypeptide-frameworks-of-photosystem-ii
#3
Ayako Tanaka, Yoshimasa Fukushima, Nobuo Kamiya
The oxygen-evolving complex (OEC) forms the heart of photosystem II (PSII) in photosynthesis. The crystal structure of PSII from Thermosynechococcus vulcanus has been reported at a resolution of 1.9 Å and at an averaged X-ray dose of 0.43 MGy. The OEC structure is suggested to be partially reduced to Mn(II) by EXAFS and DFT compu-tational studies. Recently, the "radiation-damage-free" struc-tures have been published at 1.95 Å resolution using XFEL, but reports continued to appear that the OEC is reduced to the S0-state of the Kok cycle...
January 19, 2017: Journal of the American Chemical Society
https://www.readbyqxmd.com/read/28097742/differential-dehydration-effects-on-globular-proteins-and-intrinsically-disordered-proteins-during-film-formation
#4
Juliana Sakamoto Yoneda, Andew J Miles, Ana Paula Ulian de Araujo, B A Wallace
Globular proteins composed of different secondary structures and fold types were examined by synchrotron radiation circular dichroism spectroscopy to determine the effects of dehydration on their secondary structures. They exhibited only minor changes upon removal of bulk water during film formation, contrary to previously reported studies of proteins dehydrated by lyophilisation (where substantial loss of helical structure and gain in sheet structure was detected). This near lack of conformational change observed for globular proteins contrasts with intrinsically disordered proteins (IDPs) dried in the same manner: the IDPs, which have almost completely unordered structures in solution, exhibited increased amounts of regular (mostly helical) secondary structures when dehydrated, suggesting formation of new intra-protein hydrogen bonds replacing solvent-protein hydrogen bonds, in a process which may mimic interactions that occur when IDPs bind to partner molecules...
January 18, 2017: Protein Science: a Publication of the Protein Society
https://www.readbyqxmd.com/read/28096523/x-ray-imaging-of-spin-currents-and-magnetisation-dynamics-at-the-nanoscale
#5
Stefano Bonetti
Understanding how spins move in time and space is the aim of both fundamental and applied research in modern magnetism. Over the past three decades, research in this field has led to technological advances that have had a major impact on our society, while improving the understanding of the fundamentals of spin physics. However, important questions still remain unanswered, because it is experimentally challenging to directly observe spins and their motion with a combined high spatial and temporal resolution...
January 18, 2017: Journal of Physics. Condensed Matter: An Institute of Physics Journal
https://www.readbyqxmd.com/read/28094374/combined-in-and-ex-situ-studies-of-pyrazine-adsorption-into-the-aliphatic-mof-al-cau-13-structures-dynamics-and-correlations
#6
Helge Reinsch, Jannik Benecke, Martin Etter, Niclas Heidenreich, Norbert Stock
The intercalation of different pyrazines (pyrazine, methylpyrazine, 2,5-dimethylpyrazine, 2,3-dimethylpyrazine, trimethylpyrazine and tetramethylpyrazine) into the trans-1,4-cyclohexanedicarboxylate (CDC(2-)) based Al-MOF [Al(OH)(CDC)], denoted as CAU-13, was investigated. The adsorption of the guest molecules into the flexible MOF was carried out from an aqueous solution or via vapour phase adsorption, starting with the hydrated narrow-pore form of the framework [Al(OH)(O2C-C6H10-CO2)]·H2O (CAU-13-np). The obtained host-guest systems were characterised by thermogravimetry and vibrational spectroscopy and their crystal structures were elucidated using powder X-ray diffraction (PXRD) data...
January 17, 2017: Dalton Transactions: An International Journal of Inorganic Chemistry
https://www.readbyqxmd.com/read/28087363/membrane-restructuring-following-in-situ-sialidase-digestion-of-gangliosides-complex-model-bilayers-by-synchrotron-radiation-reflectivity
#7
Valeria Rondelli, Paola Brocca, Giovanna Fragneto, Jean Daillant, Cristina Tringali, Laura Cantu', Elena Del Favero
Synchrotron radiation reflectometry was used to access the transverse structure of model membranes under the action of the human sialidase NEU2, down to the Ångström length scale. Model membranes were designed to mimic the lipid composition of so-called Glycosphingolipids Enriched Microdomains (GEMs), which are membrane platforms specifically enriched in cholesterol and sphingolipids, where also typical signalling molecules are hosted. Gangliosides, glycosphingolipids containing one or more sialic acid residues, are asymmetrically embedded in GEMs, in the outer membrane leaflet...
January 10, 2017: Biochimica et Biophysica Acta
https://www.readbyqxmd.com/read/28075578/probing-structural-perturbation-in-a-bent-molecular-crystal-with-synchrotron-infrared-microspectroscopy-and-periodic-density-functional-theory-calculations
#8
Ljupco Pejov, Manas K Panda, Taro Moriwaki, Pance Naumov
The range of unit cell orientations generated at the kink of a bent single crystal poses unsurmountable challenges with diffraction analysis and limits the insight into the molecular-scale mechanism of bending. On a plastically bent crystal of hexachlorobenzene it is demonstrated here that spatially resolved microfocus infrared spectroscopy using synchrotron radiation can be applied in conjunction with periodic density functional theory calculations to predict spectral changes or to extract information on structural changes that occur as a consequence of bending...
January 11, 2017: Journal of the American Chemical Society
https://www.readbyqxmd.com/read/28068671/high-spatial-resolution-mapping-of-catalytic-reactions-on-single-particles
#9
Chung-Yeh Wu, William J Wolf, Yehonatan Levartovsky, Hans A Bechtel, Michael C Martin, F Dean Toste, Elad Gross
The critical role in surface reactions and heterogeneous catalysis of metal atoms with low coordination numbers, such as found at atomic steps and surface defects, is firmly established. But despite the growing availability of tools that enable detailed in situ characterization, so far it has not been possible to document this role directly. Surface properties can be mapped with high spatial resolution, and catalytic conversion can be tracked with a clear chemical signature; however, the combination of the two, which would enable high-spatial-resolution detection of reactions on catalytic surfaces, has rarely been achieved...
January 11, 2017: Nature
https://www.readbyqxmd.com/read/28058831/peptide-tethered-hydrogel-scaffold-promotes-recovery-from-spinal-cord-transection-via-synergism-with-mesenchymal-stem-cells
#10
Li-Ming Li, Min Han, Xin-Chi Jiang, Xian-Zhen Yin, Fu Chen, Tian-Yuan Zhang, Hao Ren, Ji-Wen Zhang, Ting-Jun Hou, Zhong Chen, Hong-Wei Ou-Yang, Yasuhiko Tabata, You-Qing Shen, Jian-Qing Gao
Spinal cord injury (SCI) is one of the most devastating injuries. Treatment strategies for SCI are required to overcome comprehensive issues. Implantation of biomaterial scaffolds and stem cells has been demonstrated to be a promising strategy. However, a comprehensive recovery effect is difficult to achieve. In the comprehensive treatment process, the specific roles of the implanted scaffolds and of stem cells in combined strategy are usually neglected. In this study, a peptide-modified scaffold is developed based on hyaluronic acid and an adhesive peptide PPFLMLLKGSTR...
January 18, 2017: ACS Applied Materials & Interfaces
https://www.readbyqxmd.com/read/28054081/imaging-metals-in-caenorhabditis-elegans
#11
REVIEW
M Aschner, C Palinski, M Sperling, U Karst, T Schwerdtle, J Bornhorst
Systemic trafficking and storage of essential metal ions play fundamental roles in living organisms by serving as essential cofactors in various cellular processes. Thereby metal quantification and localization are critical steps in understanding metal homeostasis, and how their dyshomeostasis might contribute to disease etiology and the ensuing pathologies. Furthermore, the amount and distribution of metals in organisms can provide insight into their underlying mechanisms of toxicity and toxicokinetics. While in vivo studies on metal imaging in mammalian experimental animals are complex, time- and resource-consuming, the nematode Caenorhabditis elegans (C...
January 5, 2017: Metallomics: Integrated Biometal Science
https://www.readbyqxmd.com/read/28052677/photoionization-of-the-buckminsterfullerene-cation
#12
Suzie Douix, Denis Duflot, Denis Cubaynes, Jean-Marc Bizau, Alexandre Giuliani
Photoionization of a buckminsterfullerene ion is investigated using an ion trap and a merged beam setup coupled to synchrotron radiation beamlines and compared to theoretical calculations. Absolute measurements derived from the ion trap experiment allow discrepancies concerning the photoionization cross section of C60(+) to be solved.
January 5, 2017: Journal of Physical Chemistry Letters
https://www.readbyqxmd.com/read/28051069/a-light-responsive-self-assembly-formed-by-a-cationic-azobenzene-derivative-and-sds-as-a-drug-delivery-system
#13
Shengyong Geng, Yuzhu Wang, Liping Wang, Tsutomu Kouyama, Toshiaki Gotoh, Satoshi Wada, Jin-Ye Wang
The structure of a self-assembly formed from a cationic azobenzene derivative, 4-cholesterocarbonyl-4'-(N,N,N-triethylamine butyloxyl bromide) azobenzene (CAB) and surfactant sodium dodecyl sulfate (SDS) in aqueous solution was studied by cryo-TEM and synchrotron radiation small-angle X-ray scattering (SAXS). Both unilamellar and multilamellar vesicles could be observed. CAB in vesicles were capable to undergo reversible trans-to-cis isomerization upon UV or visible light irradiation. The structural change upon UV light irradiation could be catched by SAXS, which demonstrated that the interlamellar spacing of the cis-multilamellar vesicles increased by 0...
January 4, 2017: Scientific Reports
https://www.readbyqxmd.com/read/28048259/su-g-iep4-10-microimaging-for-different-degrees-of-human-cavernous-hemangioma-of-liver-by-using-in-line-phase-contrast-imaging-ct
#14
J Duan
PURPOSE: Cavernous hemangioma of the liver (CHL) is the most common benign solid tumor of the liver. In this study, we quantitative assessment the different degrees of CHL from microscopic viewpoint by using in-line phase-contrast imaging CT (ILPCI-CT). METHODS: The experiments were performed at x-ray imaging and biomedical application beamline (BL13W1) of Shanghai Synchrotron Radiation Facility (SSRF) in China. Three typical specimens at different stages, i.e., mild, moderate and severe human CHL were imaged using ILPCI-CT at 16keV without contrast agents...
June 2016: Medical Physics
https://www.readbyqxmd.com/read/28047081/su-f-t-673-effects-of-cardiac-induced-brain-pulsations-on-proton-minibeams
#15
J Eagle, S Marsh, E Lee, J Meyer
PURPOSE: To quantify the dosimetric impact of internal motion within the brain on spatially modulated proton minibeam radiation therapy (pMRT) for small animal research. METHODS: The peak-to-valley dose ratio (PVDR) is an essential dosimetric factor for pMRT. Motion of an animal brain caused by cardiac-induced pulsations (CIP) can impact dose deposition. For synchrotron generated high dose rate X-ray microbeams this effect is evaded due to the quasi-instantaneous delivery...
June 2016: Medical Physics
https://www.readbyqxmd.com/read/28046672/su-f-t-180-evaluation-of-a-scintillating-screen-detector-for-proton-beam-qa-and-acceptance-testing
#16
A Ghebremedhin, M Taber, P Koss, G Camargo, S Ebstein, B Patyal
PURPOSE: To test the performance of a commercial scintillating screen detector for acceptance testing and Quality Assurance of a proton pencil beam scanning system. METHOD: The detector (Lexitek DRD 400) has 40cm × 40cm field, uses a thin scintillator imaged onto a 16-bit scientific CCD with ∼0.5mm resolution. A grid target and LED illuminators are provided for spatial calibration and relative gain correction. The detector mounts to the nozzle with micron precision...
June 2016: Medical Physics
https://www.readbyqxmd.com/read/28045991/enhancement-of-iudr-radiosensitization-by-low-energy-photons-results-from-increased-and-persistent-dna-damage
#17
Emilie Bayart, Frédéric Pouzoulet, Lucie Calmels, Jonathan Dadoun, Fabien Allot, Johann Plagnard, Jean-Luc Ravanat, André Bridier, Marc Denozière, Jean Bourhis, Eric Deutsch
Low-energy X-rays induce Auger cascades by photoelectric absorption in iodine present in the DNA of cells labeled with 5-iodo-2'-deoxyuridine (IUdR). This photoactivation therapy results in enhanced cellular sensitivity to radiation which reaches its maximum with 50 keV photons. Synchrotron core facilities are the only way to generate such monochromatic beams. However, these structures are not adapted for the routine treatment of patients. In this study, we generated two beams emitting photon energy means of 42 and 50 keV respectively, from a conventional 225 kV X-ray source...
2017: PloS One
https://www.readbyqxmd.com/read/28045513/dynamic-versus-static-character-of-the-magnetic-jahn-teller-effect-magnetostructural-studies-of-fe3o-o2cph-6-py-3-clo4%C3%A2-py
#18
Anastasia N Georgopoulou, Irene Margiolaki, Vassilis Psycharis, Athanassios K Boudalis
Complex [Fe3O(O2CPh)6(py)3]ClO4·py (1) crystallizes in the hexagonal P63/m space group, and its cation exhibits a crystallographically imposed D3h symmetry due to a C3 axis passing through the oxide of its {Fe3O}(7+) core. Single-crystal unit-cell studies carried out with synchrotron radiation confirmed that this symmetry is retained down to 4.5 K; a full crystal structure determination carried out at 90 K resolved the previously reported disorder of the perchlorate anion. Magnetic susceptibility and electron paramagnetic resonance (EPR) data for complex 1 were interpreted with a model considering the retention of the threefold crystallographic symmetry while predicting a lowering of the magnetic symmetry...
January 3, 2017: Inorganic Chemistry
https://www.readbyqxmd.com/read/28040926/a-sparsity-based-iterative-algorithm-for-reconstruction-of-micro-ct-images-from-highly-undersampled-projection-datasets-obtained-with-a-synchrotron-x-ray-source
#19
S Ali Melli, Khan A Wahid, Paul Babyn, David M L Cooper, Varun P Gopi
Synchrotron X-ray Micro Computed Tomography (Micro-CT) is an imaging technique which is increasingly used for non-invasive in vivo preclinical imaging. However, it often requires a large number of projections from many different angles to reconstruct high-quality images leading to significantly high radiation doses and long scan times. To utilize this imaging technique further for in vivo imaging, we need to design reconstruction algorithms that reduce the radiation dose and scan time without reduction of reconstructed image quality...
December 2016: Review of Scientific Instruments
https://www.readbyqxmd.com/read/28040919/evaluation-of-a-flat-field-grazing-incidence-spectrometer-for-highly-charged-ion-plasma-emission-in-soft-x-ray-spectral-region-from-1-to-10-nm
#20
Thanh Hung Dinh, Yoshiki Kondo, Toshiki Tamura, Yuichi Ono, Hiroyuki Hara, Hiroki Oikawa, Yoichi Yamamoto, Masahiko Ishino, Masaharu Nishikino, Tetsuya Makimura, Padraig Dunne, Gerry O'Sullivan, Shigeru Ohta, Ken Kitano, Takeo Ejima, Tadashi Hatano, Takeshi Higashiguchi
A flat-field grazing incidence spectrometer operating on the spectral region from 1 to 10 nm was built for research on physics of high temperature and high energy density plasmas. It consists of a flat-field grating with 2400 lines/mm as a dispersing element and an x-ray charged coupled device (CCD) camera as the detector. The diffraction efficiency of the grating and the sensitivity of the CCD camera were directly measured by use of synchrotron radiation at the BL-11D beamline of the Photon Factory (PF). The influence of contamination to the spectrometer also was characterized...
December 2016: Review of Scientific Instruments
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