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https://www.readbyqxmd.com/read/28922453/disruption-of-human-stratum-corneum-lipid-structure-by-sodium-dodecyl-sulfate
#1
Kaori Yanase, Ichiro Hatta
OBJECTIVE: Surfactants are major ingredients of body soaps and cleansers. Among them, harsh ones have been demonstrated to damage the skin. Stratum corneum (SC), the outermost barrier of skin layer, is rich in intercellular lipids. This lipid structure can be disrupted by surfactants, impairing the barrier function of the skin. Thus, we investigated the surfactant-induced disruption of the intercellular lipid structure of human SC at the molecular level using synchrotron X-ray diffraction...
September 18, 2017: International Journal of Cosmetic Science
https://www.readbyqxmd.com/read/28922140/a-point-kernel-algorithm-for-microbeam-radiation-therapy
#2
Charlotte Debus, Uwe Oelfke, Stefan Bartzsch
Microbeam Radiation Therapy (MRT) is a treatment approach in radiation therapy where the treatment field is spatially fractionated into arrays of a few tens of micrometre wide planar beams of unusually high peak doses separated by low dose regions of several hundred micrometre width. In preclinical studies, this treatment approach has proven to spare normal tissue more effectively than conventional radiation therapy, while being equally efficient in tumour control. So far dose calculations in MRT, a prerequisite for future clinical applications are based on Monte Carlo simulations...
September 18, 2017: Physics in Medicine and Biology
https://www.readbyqxmd.com/read/28921972/what-can-be-learned-from-nuclear-resonance-vibrational-spectroscopy-vibrational-dynamics-and-hemes
#3
W Robert Scheidt, Jianfeng Li, J Timothy Sage
Nuclear resonance vibrational spectroscopy (NRVS; also known as nuclear inelastic scattering, NIS) is a synchrotron-based method that reveals the full spectrum of vibrational dynamics for Mössbauer nuclei. Another major advantage, in addition to its completeness (no arbitrary optical selection rules), is the unique selectivity of NRVS. The basics of this recently developed technique are first introduced with descriptions of the experimental requirements and data analysis including the details of mode assignments...
September 18, 2017: Chemical Reviews
https://www.readbyqxmd.com/read/28920686/high-pressure-synthesis-of-the-cobalt-pyrochlore-oxide-pb2co2o7-with-large-cation-mixed-occupancy
#4
Junye Yang, Jianhong Dai, Zhehong Liu, Runze Yu, Hajime Hojo, Zhiwei Hu, Tunwen Pi, Yunliang Soo, Changqing Jin, Masaki Azuma, Youwen Long
The novel A2B2O7-type compound Pb2Co2O7 was synthesized at 8 GPa and 1673 K. Synchrotron X-ray diffraction shows a cubic pyrochlore structure with space group Fd3̅m. Rietveld structural analysis reveals a large cation mixed occupancy at both A and B sites by about 40%, the greatest value found in the pyrochlore family. In combination with the X-ray absorption spectroscopy results, the specific chemical composition and charge states are determined to be (Co0.6Pb0.4)(3+)2(Pb0.6Co0.4)(4+)2O7, in which both the A-site Co(3+) and the B-site Co(4+) are low-spin...
September 18, 2017: Inorganic Chemistry
https://www.readbyqxmd.com/read/28920668/electrochemical-and-diffusional-investigation-of-na2feiipo4f-fluorophosphate-sodium-insertion-material-obtained-from-feiii-precursor
#5
Lalit Sharma, Prasant Kumar Nayak, Ezequiel de la Llave, Haomin Chen, Stefan Adams, Doron Aurbach, Prabeer Barpanda
Sodium iron fluorophosphate (Na2FeIIPO4F) was synthesized by economic solvothermal combustion technique using FeIII precursors, developing one-step carbon-coated homogeneous product. Synchrotron diffraction and Mössbauer spectroscopy revealed the formation of single-phase product assuming an orthorhombic structure (s.g. Pbcn) with FeII species. This FeIII precursor derived Na2FeIIPO4F exhibited reversible Na+ (de)intercalation with discharge capacity of 100 mAh/g at a rate of C/10 involving flat FeIII/FeII redox plateaus located at 2...
September 18, 2017: ACS Applied Materials & Interfaces
https://www.readbyqxmd.com/read/28919698/skeletal-lead-burden-of-the-british-royal-navy-in-colonial-antigua
#6
K L Giffin, T Swanston, I Coulthard, A R Murphy, D M L Cooper, T L Varney
Lead (Pb) has been known to be a cause of human poisoning since ancient times, but despite this, it was a widely used metal in the European colonial period. In this study, the relationship between Pb exposure and the demographic variables ancestry and age was explored by comparing the bone Pb levels of individuals that were of either African or European ancestry, excavated from a British Royal Navy hospital cemetery (1793-1822 CE) at English Harbour in Antigua, West Indies. More direct comparisons of Pb levels between the two ancestral groups were possible in this study because of the unsegregated nature of this cemetery...
July 2017: Int J Osteoarchaeol
https://www.readbyqxmd.com/read/28918933/structural-proteomics-topology-and-relative-accessibility-of-plant-lipid-droplet-associated-proteins
#7
Pascale Jolivet, Laure Aymé, Alexandre Giuliani, Frank Wien, Thierry Chardot, Yann Gohon
Lipid droplets are the major stock of lipids in oleaginous plant seeds. Despite their economic importance for oil production and biotechnological issues (biofuels, lubricants and plasticizers), numerous questions about their formation, structure and regulation are still unresolved. To determine water accessible domains of protein coating at lipid droplets surface, a structural proteomic approach has been performed. This technique relies on the millisecond timescale production of hydroxyl radicals by the radiolysis of water using Synchrotron X-ray white beam...
September 14, 2017: Journal of Proteomics
https://www.readbyqxmd.com/read/28915000/ductile-glass-of-polyrotaxane-toughened-by-stretch-induced-intramolecular-phase-separation
#8
Kazuaki Kato, Kaito Nemoto, Koichi Mayumi, Hideaki Yokoyama, Kohzo Ito
A new class of ductile glasses is created from a thermoplastic polyrotaxane. The hard glass, which has a Young's modulus of 1 GPa, shows crazing, necking, and strain hardening with a total elongation of 330%. Stress concentration is prevented through a unique stretch-induced intramolecular phase separation of the cyclic components and the exposed backbone. In situ synchrotron X-ray scattering studies indicate that the backbone polymer chains slip through the cyclic components in the regions where the stress is concentrated...
September 15, 2017: ACS Applied Materials & Interfaces
https://www.readbyqxmd.com/read/28912485/serial-millisecond-crystallography-for-routine-room-temperature-structure-determination-at-synchrotrons
#9
Tobias Weinert, Natacha Olieric, Robert Cheng, Steffen Brünle, Daniel James, Dmitry Ozerov, Dardan Gashi, Laura Vera, May Marsh, Kathrin Jaeger, Florian Dworkowski, Ezequiel Panepucci, Shibom Basu, Petr Skopintsev, Andrew S Doré, Tian Geng, Robert M Cooke, Mengning Liang, Andrea E Prota, Valerie Panneels, Przemyslaw Nogly, Ulrich Ermler, Gebhard Schertler, Michael Hennig, Michel O Steinmetz, Meitian Wang, Jörg Standfuss
Historically, room-temperature structure determination was succeeded by cryo-crystallography to mitigate radiation damage. Here, we demonstrate that serial millisecond crystallography at a synchrotron beamline equipped with high-viscosity injector and high frame-rate detector allows typical crystallographic experiments to be performed at room-temperature. Using a crystal scanning approach, we determine the high-resolution structure of the radiation sensitive molybdenum storage protein, demonstrate soaking of the drug colchicine into tubulin and native sulfur phasing of the human G protein-coupled adenosine receptor...
September 14, 2017: Nature Communications
https://www.readbyqxmd.com/read/28912460/elemental-and-molecular-segregation-in-oil-paintings-due-to-lead-soap-degradation
#10
Yu-Chen Karen Chen-Wiegart, Jaclyn Catalano, Garth J Williams, Anna Murphy, Yao Yao, Nicholas Zumbulyadis, Silvia A Centeno, Cecil Dybowski, Juergen Thieme
The formation of Pb, Zn, and Cu carboxylates (soaps) has caused visible deterioration in hundreds of oil paintings dating from the 15th century to the present. Through transport phenomena not yet understood, free fatty acids in the oil binding medium migrate through the paint and react with pigments containing heavy metals to form soaps. To investigate the complex correlation among the elemental segregation, types of chemical compounds formed, and possible mechanisms of the reactions, a paint sample cross-section from a 15th century oil painting was examined by synchrotron X-ray techniques...
September 14, 2017: Scientific Reports
https://www.readbyqxmd.com/read/28912363/tgf%C3%AE-transforming-growth-factor-%C3%AE-blockade-induces-a-human-like-disease-in-a-nondissecting-mouse-model-of-abdominal-aortic-aneurysm
#11
Fabien Lareyre, Marc Clément, Juliette Raffort, Stefanie Pohlod, Meghana Patel, Bruno Esposito, Leanne Master, Alison Finigan, Marie Vandestienne, Nikolaos Stergiopulos, Soraya Taleb, Bram Trachet, Ziad Mallat
OBJECTIVE: Current experimental models of abdominal aortic aneurysm (AAA) do not accurately reproduce the major features of human AAA. We hypothesized that blockade of TGFβ (transforming growth factor-β) activity-a guardian of vascular integrity and immune homeostasis-would impair vascular healing in models of nondissecting AAA and would lead to sustained aneurysmal growth until rupture. APPROACH AND RESULTS: Here, we test this hypothesis in the elastase-induced AAA model in mice...
September 14, 2017: Arteriosclerosis, Thrombosis, and Vascular Biology
https://www.readbyqxmd.com/read/28910515/chiral-kagome-lattices-from-on-surface-synthesized-molecules
#12
Tao Wang, Qitang Fan, Lin Feng, Zhijie Tao, Jianmin Huang, Huanxin Ju, Qian Xu, Shanwei Hu, Junfa Zhu
Kagome lattices have attracted much attention due to their potential applications in spin-frustrated magnetism and host-guest chemistry. Examples toward the fabrication of 2D Kagome lattices reported previously have a common feature that the precursor molecules were typically structurally intact on surface with no chemical reactions accompanied. Herein, with the combined synchrotron radiation photoelectron spectroscopy (SRPES) and scanning tunneling microscopy (STM), we demonstrated that two types of chiral Kagome lattices from on-surface synthesized organometallic compounds were fabricated, which are known as intermediates of Glaser coupling on silver single crystal surfaces...
September 14, 2017: Chemphyschem: a European Journal of Chemical Physics and Physical Chemistry
https://www.readbyqxmd.com/read/28910135/imaging-of-vanadium-in-microfossils-a-new-potential-biosignature
#13
Craig P Marshall, Alison Olcott Marshall, Jade B Aitken, Barry Lai, Stefan Vogt, Pierre Breuer, Philippe Steemans, Peter A Lay
The inability to unambiguously distinguish the biogenicity of microfossil-like structures in the ancient rock record is a fundamental predicament facing Archean paleobiologists and astrobiologists. Therefore, novel methods for discriminating biological from nonbiological chemistries of microfossil-like structures are of the utmost importance in the search for evidence of early life on Earth. This, too, is important for the search for life on Mars by in situ analyses via rovers or sample return missions for future analysis here on Earth...
September 14, 2017: Astrobiology
https://www.readbyqxmd.com/read/28910116/hard-x-ray-induced-valence-tautomeric-interconversion-in-cobalt-o-dioxolene-complexes
#14
Thiago Martins Francisco, William J Gee, Helena J Shepherd, Mark R Warren, David A Shultz, Paul R Raithby, Carlos B Pinheiro
The valence tautomeric interconversion (VTI) is a reversible process occurring in metal complexes in which an intramolecular metal-ligand electron transfer is accompanied by a change of metal ion spin state creating two switchable electronic states (redox isomers). Herein, we describe the low temperature, 30 - 100 K, single-crystal study of the [Co(diox)2(4-CN-py)2]·benzene complex (1) (diox = 3,5-di-t-butylsemiquinonate (SQ(•-)) and/or 3,5-di-t-butylcatecholate (Cat(2-)) radical; 4-CN-py = 4-cyano-pyridine) using hard synchrotron X-ray radiation with different intensities...
September 14, 2017: Journal of Physical Chemistry Letters
https://www.readbyqxmd.com/read/28906570/probing-novel-microstructural-evolution-mechanisms-in-aluminum-alloys-using-4d-nanoscale-characterization
#15
C Shashank Kaira, V De Andrade, Sudhanshu S Singh, C Kantzos, Antony Kirubanandham, F De Carlo, Nikhilesh Chawla
Dispersions of nanoscale precipitates in metallic alloys have been known to play a key role in strengthening, by increasing their strain hardenability and providing resistance to deformation. Although these phenomena have been extensively investigated in the last century, the traditional approaches employed in the past have not rendered an authoritative microstructural understanding in such materials. The effect of the precipitates' inherent complex morphology and their 3D spatial distribution on evolution and deformation behavior have often been precluded...
September 14, 2017: Advanced Materials
https://www.readbyqxmd.com/read/28905399/microdosimetric-measurements-of-a-clinical-proton-beam-with-micrometer-sized-solid-state-detector
#16
Sarah E Anderson, Keith M Furutani, Linh T Tran, Lachlan Chartier, Marco Petasecca, Michael Lerch, Dale A Prokopovich, Mark Reinhard, Vladimir L Perevertaylo, Anatoly B Rosenfeld, Michael G Herman, Chris Beltran
PURPOSE: Microdosimetry is a vital tool for assessing the microscopic patterns of energy deposition by radiation, which ultimately govern biological effect. Solid-state, silicon-on-insulator microdosimeters offer an approach for making microdosimetric measurements with high spatial resolution (on the order of tens of micrometers). These high-resolution, solid-state microdosimeters may therefore play a useful role in characterizing proton radiotherapy fields, particularly for making highly-resolved measurements within the Bragg peak region...
September 14, 2017: Medical Physics
https://www.readbyqxmd.com/read/28905245/identification-of-polymorphic-forms-of-active-pharmaceutical-ingredient-in-low-concentration-dry-powder-formulations-by-synchrotron-x-ray-powder-diffraction
#17
Kenji Egusa, Fumiaki Okazaki, Joerg Schiewe, Ulrike Werthmann, Markus Wolkenhauer
BACKGROUND: The identification of different (pseudo) polymorphs of an active pharmaceutical ingredient in dry powder formulations is of importance during development and entire product lifecycle, e.g., quality control. Whereas determination of polymorphic differences of pure substances is rather easy, in dry powder formulations, it is generally difficult and the difficulties increase particularly, if the substance of interest is present only in low concentrations in the formulation. Such a formulation is SpirivaR inhalation powder (Boehringer Ingelheim), which contains only 0...
September 13, 2017: Drugs in R&D
https://www.readbyqxmd.com/read/28902506/non-invasive-synchrotron-based-x-ray-raman-scattering-discriminates-carbonaceous-compounds-in-ancient-and-historical-materials
#18
Pierre Gueriau, Jean-Pascal Rueff, Sylvain Bernard, Josiane Albert Kaddissy, Sarah Goler, Christoph J Sahle, Dimosthenis Sokaras, Roy A Wogelius, Philip L Manning, Uwe Bergmann, Loïc Bertrand
Carbon compounds are ubiquitous and occur in a diversity of chemical forms in many systems including ancient and historic materials ranging from cultural heritage to paleontology. Determining their speciation cannot only provide unique information on their origin, but may also elucidate degradation processes. Synchrotron-based X-ray absorption near-edge structure (XANES) spectroscopy at the carbon K-edge (280-350 eV) is a very powerful method to probe carbon speciation. However, the short penetration depth of soft X-rays imposes stringent constraints on sample type, preparation and analytical environment...
September 13, 2017: Analytical Chemistry
https://www.readbyqxmd.com/read/28901620/assessment-of-the-spectral-performance-of-hybrid-photon-counting-x-ray-detectors
#19
Peter Trueb, Pietro Zambon, Christian Broennimann
PURPOSE: Hybrid Photon Counting (HPC) detectors profoundly improved x-ray diffraction experiments at third generation synchrotron facilities. Enabling the simultaneous measurement of x-ray intensities in multiple energy bins, they also have many potential applications in the field of medical imaging. A prerequisite for this is a clean spectral response. To quantify how efficiently HPC detectors are able to assign photons to the correct energy bin, a quantity called Spectral Efficiency (SE) is introduced...
September 2017: Medical Physics
https://www.readbyqxmd.com/read/28901355/two-dimensional-metal-nacu6-3sb3-and-solid-state-transformations-of-sodium-copper-antimonides
#20
B Owens-Baird, S Lee, K Kovnir
A novel layered compound, NaCu6.3Sb3, has been successfully synthesized from elements. This unique structure crystallizes in the hexagonal space group P63/mmc and has lattice constants of a = 4.2166(2) Å and c = 24.041(1) Å. The structure consists of complex Cu/Sb 2D blocks separated by Na ions. These blocks contain graphene-like hexagonal layers of either Cu or CuSb. The solid-state transformations in the Na-Cu-Sb system between Cu2Sb-NaCu6.3Sb3-NaCu4Sb2 were explored using annealing at different partial vapor pressures of Na, differential scanning calorimetry, and in situ synchrotron powder X-ray diffraction...
September 13, 2017: Dalton Transactions: An International Journal of Inorganic Chemistry
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