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https://www.readbyqxmd.com/read/29775319/operando-evidence-for-a-universal-oxygen-evolution-mechanism-on-thermal-and-electrochemical-iridium-oxides
#1
Viktoriia A Saveleva, Li Wang, Detre Teschner, Travis E Jones, Aldo S Gago, K Andreas Friedrich, Spyridon Zafeiratos, Robert Schloegl, Elena R Savinova
Progress in the development of the proton exchange membrane (PEM) water electrolysis technology requires decreasing the anode overpotential, where the sluggish multistep oxygen evolution reaction (OER) occurs. This calls for the understanding of the nature of the active OER sites and reaction intermediates, which are still being debated. In this work, we apply synchrotron radiation - based near ambient pressure X-ray photoelectron and absorption spectroscopies under operando conditions in order to unveil the nature of the reaction intermediates and shed light on the OER mechanism on electrocatalysts most widely used in PEM electrolyzers - electrochemical and thermal iridium oxides...
May 18, 2018: Journal of Physical Chemistry Letters
https://www.readbyqxmd.com/read/29774355/3d-negative-thermal-expansion-in-orthorhombic-mil-68-in
#2
Zhanning Liu, Qiang Li, He Zhu, Kun Lin, Jinxia Deng, Jun Chen, Xianran Xing
Negative thermal expansion (NTE), lattice contraction upon heating, has been found in some metal organic frameworks (MOFs). To date, MOF compounds have been found to present either isotropic NTE in the cubic phase or 1D or 2D NTE in a low symmetry structure. Herein, we report anisotropic NTE in orthorhombic MIL-68(In) with the 3D NTE of αa = -5.6 × 10-6 K-1, αb = -2.7 × 10-6 K-1 and αc = -4.0 × 10-6 K-1. A synchrotron X-ray diffraction study shows that the transverse vibration of the phenyl ring leads to the NTE in the ab plane...
May 18, 2018: Chemical Communications: Chem Comm
https://www.readbyqxmd.com/read/29773822/origin-of-magnetic-properties-in-carbon-implanted-zno-nanowires
#3
Y F Wang, Y C Shao, S H Hsieh, Y K Chang, P H Yeh, H C Hsueh, J W Chiou, H T Wang, S C Ray, H M Tsai, C W Pao, C H Chen, H J Lin, J F Lee, C T Wu, J J Wu, Y M Chang, K Asokan, K H Chae, T Ohigashi, Y Takagi, T Yokoyama, N Kosugi, W F Pong
Various synchrotron radiation-based spectroscopic and microscopic techniques are used to elucidate the room-temperature ferromagnetism of carbon-doped ZnO-nanowires (ZnO-C:NW) via a mild C+ ion implantation method. The photoluminescence and magnetic hysteresis loops reveal that the implantation of C reduces the number of intrinsic surface defects and increases the saturated magnetization of ZnO-NW. The interstitial implanted C ions constitute the majority of defects in ZnO-C:NW as confirmed by the X-ray absorption spectroscopic studies...
May 17, 2018: Scientific Reports
https://www.readbyqxmd.com/read/29772895/reversible-assembly-of-a-drug-peptide-into-amyloid-fibrils-a-dynamic-circular-dichroism-study
#4
Frédéric Gobeaux, Frank Wien
The common view on the amyloid fibril formation is that it is a multistep process that involves many oligomeric intermediate species, which leads to a high degree of polymorphism. This view derives from numerous kinetic studies whose vast majority was carried out with amyloid β fragments or other pathological amyloidogenic sequences. Yet, it is not clear whether the mechanisms inferred from these studies are universal and also apply to functional amyloids, in particular to peptide hormones which form reversible amyloid structures...
May 18, 2018: Langmuir: the ACS Journal of Surfaces and Colloids
https://www.readbyqxmd.com/read/29772689/fabrication-and-characterization-of-nanoenergetic-hollow-spherical-hexanitrostibene-hns-derivatives
#5
Xiong Cao, Peng Deng, Shuangqi Hu, Lijun Ren, Xiaoxia Li, Peng Xiao, Yu Liu
The spherization of nanoenergetic materials is the best way to improve the sensitivity and increase loading densities and detonation properties for weapons and ammunition, but the preparation of spherical nanoenergetic materials with high regularization, uniform size and monodispersity is still a challenge. In this paper, nanoenergetic hollow spherical hexanitrostibene (HNS) derivatives were fabricated via a one-pot copolymerization strategy, which is based on the reaction of HNS and piperazine in acetonitrile solution...
May 16, 2018: Nanomaterials
https://www.readbyqxmd.com/read/29771123/carotenoids-experimental-ionization-energies-and-capacity-at-inhibiting-lipid-peroxidation-in-a-chemical-model-of-dietary-oxidative-stress
#6
Olivier Dangles, Pascale Goupy, Michel Carail, Alexandre Giuliani, Denis Duflot, Catherine Caris-Veyrat
Carotenoids are important natural pigments and micronutrients contributing to health prevention by several mechanisms, including their electron-donating (antioxidant) activity. In this work, a large series of carotenoids, including 11 carotenes and 14 xanthophylls, has been investigated by wavelength-resolved atmospheric pressure photoionization mass spectrometry (DISCO line of SOLEIL synchrotron), thus allowing the experimental determination of their ionization energy (IE) for the first time. On the other hand, the carotenoids have been also investigated for their ability to inhibit the heme iron-induced peroxidation of linoleic acid in mildly acidic micelles, a simple but relevant chemical model of oxidative stress in the gastric compartment...
May 17, 2018: Journal of Physical Chemistry. B
https://www.readbyqxmd.com/read/29768016/cisplatin-encapsulation-generates-morphologically-different-multi-compartments-in-the-internal-nanostructures-of-non-lamellar-liquid-crystalline-self-assemblies
#7
Intan Diana Mat Azmi, Jesper Ostergaard, Stefan Sturup, Bente Gammelgaard, Arto Urtti, Seyed Moein Moghimi, Anan Yaghmur
Cisplatin (cis-diamminedichloroplatinum (II)) is among the most potent cytotoxic agents used in cancer chemotherapy. The encapsulation of cisplatin in lipid-based drug carriers has been challenging owing to its low solubility in both aqueous and lipid phases. Here, we investigated cisplatin encapsulation in non-lamellar liquid crystalline (LC) nanodispersions formed from a ternary mixture of phytantriol (PHYT), vitamin E (Vit E) and an anionic phospholipid [either phosphatidylglycerol (DSPG) or phosphatidylserine (DPPS)]...
May 16, 2018: Langmuir: the ACS Journal of Surfaces and Colloids
https://www.readbyqxmd.com/read/29767517/formation-of-zno-4-tetrahedra-and-zno-6-octahedra-in-tezno-3-synthesized-under-high-pressure
#8
Jianhong Dai, Xudong Shen, Zhehong Liu, Qing Zhao, Xiao Wang, Cheng Dong, Yuecheng Bian, Wei Ding, Zhigao Sheng, Masaki Azuma, Youwen Long
A new TeZnO3 phase was synthesized by high-pressure techniques. Different from the ambient-pressure orthorhombic phase composed of ZnO5 units, the current high-pressure one crystallizes to a monoclinic structure with space group P21 / n. Moreover, both ZnO4 tetrahedral and ZnO6 octahedral polyhedra are found to occur in this new phase, providing a unique Zn-based material system that simultaneously possesses two distinct coordinated units. Because the outermost orbitals are fully occupied for both Zn2+ and Te4+ , the compound exhibits diamagnetism and strong insulating behavior with a wide bandgap as large as 6...
May 16, 2018: Inorganic Chemistry
https://www.readbyqxmd.com/read/29765746/crystal-structure-of-2-13-bis-acetamido-5-16-dimethyl-2-6-13-17-tetra-aza-tri-cyclo-16-4-0-0-7-12-docosane-%C3%AE%C2%BA-4-n-silver-ii-dinitrate-from-synchrotron-x-ray-data
#9
Dohyun Moon, Jong-Ha Choi
The asymmetric unit of the title compound, [Ag(C24 H46 N6 O2 )](NO3 )2 [C24 H46 N6 O2 is (5,16-dimethyl-2,6,13,17-tetra-aza-tri-cyclo-[16.4.0.07,12 ]docosane-2,13-di-yl)diacetamide, L ], consists of one independent half of the [Ag(C24 H46 N6 O2 )]2+ cation and one nitrate anion. The Ag atom, lying on an inversion centre, has a square-planar geometry and the complex adopts a stable trans -III conformation. Inter-estingly, the two O atoms of the pendant acetamide groups are not coordinated to the AgII ion. The longer distance of 2...
April 1, 2018: Acta Crystallographica. Section E, Crystallographic Communications
https://www.readbyqxmd.com/read/29765710/design-of-new-anti-alzheimer-drugs-ring-expansion-synthesis-and-synchrotron-x-ray-diffraction-study-of-dimethyl-4-ethyl-11-fluoro-1-4-5-6-7-8-hexa-hydro-azonino-5-6-b-indole-2-3-di-carboxyl-ate
#10
Flavien A A Toze, Anna V Listratova, Leonid G Voskressensky, Natalia Yu Chernikova, Nikolai N Lobanov, Alexey N Bilyachenko, Pavel V Dorovatovskii
The title compound, C20 H23 FN2 O4 , is the product of a ring-expansion reaction from a seven-membered fluorinated hexa-hydro-azepine to a nine-membered azonine. The nine-membered azonine ring of the mol-ecule adopts a chair-boat conformation. The C=C and C-N bond lengths [1.366 (3) and 1.407 (3) Å, respectively] indicate the presence of conjugation within the enamine CH2 -C=C-N-CH2 fragment. The substituent planes at the C=C double bond of this fragment are twisted by 16.0 (3)° as a result of steric effects...
March 1, 2018: Acta Crystallographica. Section E, Crystallographic Communications
https://www.readbyqxmd.com/read/29765706/crystal-structure-of-silver-propane-1-3-diyl-dinitrilo-%C3%AE%C2%BA-2-n-n-tetra-acetato-%C3%AE%C2%BA-4-o-o-o-o-chromate-iii-from-synchrotron-x-ray-data
#11
Dohyun Moon, Keon Sang Ryoo, Jong-Ha Choi
The asymmetric unit of the title compound, Ag[Cr(C11 H14 N2 O8 )]·3H2 O, contains one [Cr(1,3-pdta)]- anion [1,3-pdta is (propane-1,3-diyldi-nitrilo)-tetra-acetate], one Ag+ cation and three water mol-ecules. The Cr3+ ion is coordinated to the four O and two N atoms of the 1,3-pdta ligand, displaying a distorted octa-hedral geometry. The mean Cr-N and Cr-O bond lengths are 2.0727 (17) and 1.9608 (15) Å, respectively. The conformations of the chelate rings were found to be envelope for the glycinates and twist-boat for the six-membered di-amine ( T ) ring...
March 1, 2018: Acta Crystallographica. Section E, Crystallographic Communications
https://www.readbyqxmd.com/read/29765605/pressure-induced-coherent-sliding-layer-transition-in-the-excitonic-insulator-ta-2-nise-5
#12
Akitoshi Nakano, Kento Sugawara, Shinya Tamura, Naoyuki Katayama, Kazuyuki Matsubayashi, Taku Okada, Yoshiya Uwatoko, Kouji Munakata, Akiko Nakao, Hajime Sagayama, Reiji Kumai, Kunihisa Sugimoto, Naoyuki Maejima, Akihiko Machida, Tetsu Watanuki, Hiroshi Sawa
The crystal structure of the excitonic insulator Ta2 NiSe5 has been investigated under a range of pressures, as determined by the complementary analysis of both single-crystal and powder synchrotron X-ray diffraction measurements. The monoclinic ambient-pressure excitonic insulator phase II transforms upon warming or under a modest pressure to give the semiconducting C -centred orthorhombic phase I. At higher pressures ( i.e. >3 GPa), transformation to the primitive orthorhombic semimetal phase III occurs...
March 1, 2018: IUCrJ
https://www.readbyqxmd.com/read/29765420/a-feasible-method-of-angiogenesis-assessment-in-gastric-cancer-using-3d-microvessel-density
#13
Lu Zhang, Fei Zheng, Zhigang Peng, Zijing Hu, Zhi Yang
Background: Cancer stem cell (CSC) promotes angiogenesis which plays an important role in tumor occurrence, growth, and metastasis. Accurately, quantifying the tumor vasculature can help understanding CSC characteristics and improve cancer diagnosis, therapy planning, and evaluation. The objective of this study is to present a method for improved angiogenesis assessment. Methods: We proposed a three-dimensional microvessel density (3D MVD) to evaluate tumor angiogenesis and tested it in animal models...
2018: Stem Cells International
https://www.readbyqxmd.com/read/29764149/vacuum-ultraviolet-photoionization-cross-section-of-the-hydroxyl-radical
#14
Leah G Dodson, John D Savee, Samer Gozem, Linhan Shen, Anna I Krylov, Craig A Taatjes, David L Osborn, Mitchio Okumura
The absolute photoionization spectrum of the hydroxyl (OH) radical from 12.513 to 14.213 eV was measured by multiplexed photoionization mass spectrometry with time-resolved radical kinetics. Tunable vacuum ultraviolet (VUV) synchrotron radiation was generated at the Advanced Light Source. OH radicals were generated from the reaction of O(1 D) + H2 O in a flow reactor in He at 8 Torr. The initial O(1 D) concentration, where the atom was formed by pulsed laser photolysis of ozone, was determined from the measured depletion of a known concentration of ozone...
May 14, 2018: Journal of Chemical Physics
https://www.readbyqxmd.com/read/29762050/dl-3-n-butylphthalide-attenuates-ischemic-reperfusion-injury-by-improving-the-function-of-cerebral-artery-and-circulation
#15
Chuan Qin, Panting Zhou, Liping Wang, Muyassar Mamtilahun, Wanlu Li, Zhijun Zhang, Guo-Yuan Yang, Yongting Wang
Dl-3-N-butylphthalide (NBP) is approved in China for the treatment of ischemic stroke. Previous studies have shown that NBP promotes recovery after stroke via multiple mechanisms. However, the effect of NBP on vascular function and thrombosis remains unclear. Here, we aim to study the effect of NBP on vascular function using a rat model of transient middle cerebral artery occlusion (MCAO) and a state-of-the-art high-resolution synchrotron radiation angiography. Eighty SD rats underwent MCAO surgery. NBP (90 mg/kg) was administrated daily by gavage...
January 1, 2018: Journal of Cerebral Blood Flow and Metabolism
https://www.readbyqxmd.com/read/29762013/determination-of-hexavalent-chromium-fractions-in-plastics-using-laboratory-based-high-resolution-x-ray-emission-spectroscopy
#16
Evan P Jahrman, Gerald T Seidler, John R Sieber
Cr(VI) is a well-known human carcinogen with many water-soluble moieties. Its presence in both natural and man-made substances poses a risk to public health, especially when contamination of ground water is possible. This has led the European Union and other jurisdictions to include Cr(VI) in restriction of hazardous substances (RoHS) regulations. However, for several important industrial and commercial purposes, analytical capability to characterize Cr(VI) is known to be insufficient for regulatory purposes...
May 15, 2018: Analytical Chemistry
https://www.readbyqxmd.com/read/29761824/impact-of-cardio-synchronous-brain-pulsations-on-monte-carlo-calculated-doses-for-synchrotron-micro-and-mini-beam-radiation-therapy
#17
Francisco Manchado de Sola, Manuel Vilches, Yolanda Prezado, Antonio M Lallena
PURPOSE: To assess the effects of brain movements induced by heartbeat on dose distributions in synchrotron micro- and mini-beam radiaton therapy and to develop a model to help guide decisions and planning for future clinical trials. METHODS: The Monte Carlo code PENELOPE was used to simulate the irradiation of a human head phantom with a variety of micro- and mini-beam arrays, with beams narrower than 100 μm and above 500 μm, respectively, and with radiation fields of 1cm × 2cm and 2cm × 2cm...
May 15, 2018: Medical Physics
https://www.readbyqxmd.com/read/29761472/cranial-morphology-in-mollisquama-sp-squaliformes-dalatiidae-and-patterns-of-cranial-evolution-in-dalatiid-sharks
#18
John S S Denton, John G Maisey, Mark Grace, Alan Pradel, Michael H Doosey, Henry L Bart, Gavin J P Naylor
Dalatiid sharks are members of a family of predominantly small, midwater meso- and bathypelagic chondrichthyans. The family is notable for both its number of monotypic genera and high morphological disparity. Three of the seven dalatiid genera are known only from holotype specimens (Mollisquama parini) or from only a handful of specimens (Euprotomicroides zantedeschia, Heteroscymnoides marleyi), with the only detailed anatomical work consistent across all taxa being studies of dentition. Here, we present detailed anatomical description of the second-ever specimen of Mollisquama (Mollisquama sp...
May 14, 2018: Journal of Anatomy
https://www.readbyqxmd.com/read/29760396/correlating-photoluminescence-and-structural-properties-of-uncapped-and-gaas-capped-epitaxial-ingaas-quantum-dots
#19
Arka B Dey, Milan K Sanyal, Ian Farrer, Karthick Perumal, David A Ritchie, Qianqian Li, Jinsong Wu, Vinayak Dravid
The understanding of the correlation between structural and photoluminescence (PL) properties of self-assembled semiconductor quantum dots (QDs), particularly InGaAs QDs grown on (001) GaAs substrates, is crucial for both fundamental research and optoelectronic device applications. So far structural and PL properties have been probed from two different epitaxial layers, namely top-capped and buried layers respectively. Here, we report for the first time both structural and PL measurements from an uncapped layer of InGaAs QDs to correlate directly composition, strain and shape of QDs with the optical properties...
May 14, 2018: Scientific Reports
https://www.readbyqxmd.com/read/29760096/an-operando-x-ray-diffraction-study-of-chloroaluminate-anion-graphite-intercalation-in-aluminum-batteries
#20
Chun-Jern Pan, Chunze Yuan, Guanzhou Zhu, Qian Zhang, Chen-Jui Huang, Meng-Chang Lin, Michael Angell, Bing-Joe Hwang, Payam Kaghazchi, Hongjie Dai
We investigated rechargeable aluminum (Al) batteries composed of an Al negative electrode, a graphite positive electrode, and an ionic liquid (IL) electrolyte at temperatures down to -40 °C. The reversible battery discharge capacity at low temperatures could be superior to that at room temperature. In situ/operando electrochemical and synchrotron X-ray diffraction experiments combined with theoretical modeling revealed stable AlCl4 - /graphite intercalation up to stage 3 at low temperatures, whereas intercalation was reversible up to stage 4 at room temperature (RT)...
May 14, 2018: Proceedings of the National Academy of Sciences of the United States of America
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