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https://www.readbyqxmd.com/read/29334611/understanding-complex-tribofilms-by-means-of-h3bo3-b2o3-model-glasses
#1
Fabiana Spadaro, Antonella Rossi, Shivaprakash N Ramakrishna, Emmanuel Lainé, Philip Woodward, Nicholas D Spencer
The discovery of the spontaneous reaction of boric oxides with moisture in the air to form lubricious H3BO3 films has led to great interest in the tribology of boron compounds in general. Despite this, a study of the growth kinetics of H3BO3 on a B2O3 substrate under controlled relative humidity (RH), has not yet been reported in the literature. Here, we describe the tribological properties of H3BO3-B2O3 glass systems after aging under controlled relative humidity over different lengths of time. A series of tribological tests has been performed applying a normal load of 15 N, at both room temperature and 100°C in Yubase 4 oil...
January 15, 2018: Langmuir: the ACS Journal of Surfaces and Colloids
https://www.readbyqxmd.com/read/29334459/development-of-charmm-compatible-force-field-parameters-for-cobalamin-and-related-cofactors-from-quantum-mechanical-calculations
#2
Anna Pavlova, Jerry M Parks, James C Gumbart
Corrinoid cofactors such as cobalamin are used by many enzymes and are essential for most living organisms. Therefore, there is broad interest in investigating cobalamin-protein interactions with molecular dynamics simulations. Previously developed parameters for cobalamins are based mainly on crystal structure data. Here, we report CHARMM-compatible force field parameters for several corrinoids developed from quantum mechanical calculations. We provide parameters for corrinoids in three oxidation states, Co3+, Co2+ and Co1+, and with various axial ligands...
January 15, 2018: Journal of Chemical Theory and Computation
https://www.readbyqxmd.com/read/29334395/probing-the-geometry-of-copper-and-silver-adatoms-on-magnetite-quantitative-experiment-versus-theory
#3
Matthias Meier, Zdeněk Jakub, Jan Balajka, Jan Hulva, Roland Bliem, Pardeep K Thakur, Tien-Lin Lee, Cesare Franchini, Michael Schmid, Ulrike Diebold, Francesco Allegretti, David A Duncan, Gareth S Parkinson
Accurately modelling the structure of a catalyst is a fundamental prerequisite for correctly predicting reaction pathways, but a lack of clear experimental benchmarks makes it difficult to determine the optimal theoretical approach. Here, we utilize the normal incidence X-ray standing wave (NIXSW) technique to precisely determine the three dimensional geometry of Ag1 and Cu1 adatoms on Fe3O4(001). Both adatoms occupy bulk-continuation cation sites, but with a markedly different height above the surface (0.43 ± 0...
January 15, 2018: Nanoscale
https://www.readbyqxmd.com/read/29334394/substitution-of-the-laser-borane-anti-b18h22-with-pyridine-a-structural-and-photophysical-study-of-some-unusually-structured-macropolyhedral-boron-hydrides
#4
Michael G S Londesborough, Jiří Dolanský, Tomáš Jelínek, John D Kennedy, Ivana Císařová, Robert D Kennedy, Daniel Roca-Sanjuán, Antonio Francés-Monerris, Kamil Lang, William Clegg
Reaction of anti-B18H221 with pyridine in neutral solvents gives sparingly soluble B16H18-3',8'-Py23a as the major product (ca. 53%) and B18H20-6',9'-Py22 (ca. 15%) as the minor product, with small quantities of B18H20-8'-Py 4 (ca. 1%) also being formed. The three new compounds 2, 3a and 4 are characterized by single-crystal X-ray diffraction analyses and by multinuclear multiple-resonance NMR spectroscopy. Compound 2 is of ten-vertex nido:ten-vertex arachno two-atoms-in-common architecture, long postulated for a species with borons-only cluster constitution, but previously elusive...
January 15, 2018: Dalton Transactions: An International Journal of Inorganic Chemistry
https://www.readbyqxmd.com/read/29334360/self-consistent-description-of-local-density-dynamics-in-simple-liquids-the-case-of-molten-lithium
#5
Anatolii Mokshin, Bulat N Galimzyanov
The dynamic structure factor is the quantity, which can be measured by means of Brillouin light-scattering as well as by means of inelastic scattering of neutrons and X-rays. The spectral (or frequency) moments of the dynamic structure factor define directly the sum rules of the scattering law. The theoretical scheme formulated in this study allows one to describe the dynamics of local density fluctuations in simple liquids and to obtain the expression of the dynamic structure factor in terms of the spectral moments...
January 15, 2018: Journal of Physics. Condensed Matter: An Institute of Physics Journal
https://www.readbyqxmd.com/read/29334167/cross-linking-mass-spectrometry-for-studying-protein-structures-and-protein-protein-interactions-where-are-we-now-and-where-should-we-go-from-here
#6
Andrea Sinz
Structural mass spectrometry (MS) is gaining increasing importance in deriving valuable three-dimensional structural information on proteins and protein complexes and complements existing techniques, such as NMR spectroscopy and X-ray crystallography. Structural MS unites different MS-based techniques, i.e, hydrogen-deuterium exchange, native MS, ion-mobility MS, protein footprinting, and chemical cross-linking/MS, and allows fundamental questions in structural biology to be addressed. In this article, I will focus on the cross-linking/MS strategy...
January 15, 2018: Angewandte Chemie
https://www.readbyqxmd.com/read/29334160/fine-tuning-of-molecular-packing-and-energy-level-through-methyl-substitution-enabling-excellent-small-molecule-acceptors-for-nonfullerene-polymer-solar-cells-with-efficiency-up-to-12-54
#7
Zhenghui Luo, Haijun Bin, Tao Liu, Zhi-Guo Zhang, Yankang Yang, Cheng Zhong, Beibei Qiu, Guanghao Li, Wei Gao, Dongjun Xie, Kailong Wu, Yanming Sun, Feng Liu, Yongfang Li, Chuluo Yang
A novel small molecule acceptor MeIC with a methylated end-capping group is developed. Compared to unmethylated counterparts (ITCPTC), MeIC exhibits a higher lowest unoccupied molecular orbital (LUMO) level value, tighter molecular packing, better crystallites quality, and stronger absorption in the range of 520-740 nm. The MeIC-based polymer solar cells (PSCs) with J71 as donor, achieve high power conversion efficiency (PCE), up to 12.54% with a short-circuit current (JSC ) of 18.41 mA cm-2 , significantly higher than that of the device based on J71:ITCPTC (11...
January 15, 2018: Advanced Materials
https://www.readbyqxmd.com/read/29334137/calcium-phosphate-precipitation-in-experimental-gaps-between-fluoride-containing-fast-setting-calcium-silicate-cement-and-dentin
#8
Bahram Ranjkesh, Ming Ding, Michel Dalstra, Jens R Nyengaard, Jacques Chevallier, Flemming Isidor, Henrik Løvschall
A novel fast-setting calcium silicate cement containing fluoride (novel-CSC) has been developed for applications in tooth crowns. The aim of this study was to assess the ability of the novel-CSC to close the experimental gaps at the dentin-cement interface. The novel-CSC was tested against Vitrebond and GC Fuji II LC. Experimental gaps of 50 or 300 μm width were created between the materials and dentin. Specimens with the 300-μm-wide gap were immersed in phosphate-buffered saline and the closed gap area was measured during 96 h...
January 15, 2018: European Journal of Oral Sciences
https://www.readbyqxmd.com/read/29334109/a-multifunctional-supramolecular-hydrogel-preparation-properties-and-molecular-assembly
#9
Lin Wang, Xuefeng Shi, Yaqian Wu, Jian Zhang, Yuejun Zhu, Jinben Wang
A novel supramolecular hydrogel was designed and constructed by molecular self-assembly of a cationic gemini surfactant, 1,3-bis(N,N-dimethyl-N-cetylammonium)-2-propylacrylate dibromide (AGC16), and an anionic aromatic compound, trisodium 1,3,6-naphthalenetrisulfonate (NTS). Owing to its unique structure, the hydrogel (abbreviated as AGC16/NTS) has the potential to be used as a multifunctional drug delivery system. The structure and properties of AGC16/NTS were characterized by rheological measurements, differential scanning calorimetry, variable-temperature 1H nuclear magnetic resonance, ultraviolet-visible spectroscopy, variable-temperature fluorescence emission spectroscopy, cryogenic scanning electron microscopy, transmission electron microscopy and X-ray diffraction methods...
January 15, 2018: Soft Matter
https://www.readbyqxmd.com/read/29334076/pt-decorated-mos-sub-2-sub-nanoflakes-for-ultrasensitive-resistive-humidity-sensor
#10
Debasree Burman, Sumita Santra, Panchanan Pramanik, Prasanta Kumar Guha
In this work, we report the fabrication of a low power, humidity sensor where platinum nanoparticles (NPs) decorated few-layered Molybdenum disulphide (MoS<sub>2</sub>) nanoflakes have been used as the sensing layer. A mixed solvent was used to exfoliate the nanoflakes from the bulk powder. Then the Pt/MoS<sub>2</sub> composites were prepared by reducing Pt NPs from chloroplatinic acid hexahydrate using a novel reduction technique using sulfide salt. The successful reduction and composite preparation were confirmed using various material characterization tools like Scanning Electron Microscopy (SEM), Atomic Force Microscopy (AFM), Transmission Electron Microscopy (TEM), X-Ray Diffraction (XRD), X-ray Photoelectron Spectroscopy (XPS), Raman spectroscopy and UV-visible spectroscopy (UV-Vis)...
January 15, 2018: Nanotechnology
https://www.readbyqxmd.com/read/29334027/patient-specific-quality-assurance-using-monte-carlo-dose-calculation-and-elekta-log-files-for-prostate-volumetric-modulated-arc-therapy
#11
Yoshiyuki Katsuta, Noriyuki Kadoya, Yukio Fujita, Eiji Shimizu, Kenichi Matsunaga, Kinya Sawada, Haruo Matsushita, Kazuhiro Majima, Keiichi Jingu
Log file-based methods are attracting increasing interest owing to their ability to validate volumetric-modulated arc therapy outputs with high resolution in the leaf and gantry positions and in delivered dose. Cross-validation of these methods for comparison with measurement-based methods using the ionization chamber/ArcCHECK-3DVH software (version 3.2.0) under the same conditions of treatment anatomy and plan enables an efficient evaluation of this method. In this study, with the purpose of cross-validation, we evaluate the accuracy of a log file-based method using Elekta log files and an X-ray voxel Monte Carlo dose calculation technique in the case of leaf misalignment during prostate volumetric-modulated arc therapy...
December 2017: Technology in Cancer Research & Treatment
https://www.readbyqxmd.com/read/29333810/the-value-of-acute-phase-reactants-and-lightcycler%C3%A2-septifast-test-in-the-diagnosis-of-bacterial-and-viral-infections-in-pediatric-patients
#12
Gulcin Bozlu, Huseyin Tanriverdi, Gonul Aslan, Necdet Kuyucu
INTRODUCTION: This study was performed to investigate the value of acute phase reactants and LightCycler® SeptiFast test to differentiate bacterial and viral infections. POPULATION AND METHODS: Children with fever were enrolled to this prospective study. Peripheral white blood cell (WBC), C-reactive protein (CRP) and procalcitonin (PCT) were studied from all patients on day 1, 3 and 7. Blood culture and chest X-ray were also obtained on day 1. Blood samples for LightCycler® SeptiFast test were obtained in all patients to use them if there was uncertain diagnosis between bacterial or viral infection...
February 1, 2018: Archivos Argentinos de Pediatría
https://www.readbyqxmd.com/read/29333766/-relationship-between-different-x-ray-appearances-and-oral-clinical-manifestations-of-cemental-dysplasia
#13
Wang Hu
Cemental dysplasia is a non-neoplastic lesion and features different X-ray appearances that easily confuse dentists. This condition is often observed in conventional dental films or occasionally on panoramic radiographs. Cemental dysplasia is easily misdiagnosed as chronic periapical periodontitis, osteomyelitis, and tumor. In this paper, clinical mani-festations, imaging diagnosis, and the correlation between these variables are analyzed to achieve correct diagnosis.
December 1, 2017: Hua Xi Kou Qiang Yi Xue za Zhi, Huaxi Kouqiang Yixue Zazhi, West China Journal of Stomatology
https://www.readbyqxmd.com/read/29333693/polypeptide-polymer-brushes-by-light-induced-surface-polymerization-of-amino-acid-n-carboxyanhydrides
#14
Timo Stukenkemper, Xavier Paquez, M W G M Verhoeven, Emiel J M Hensen, Aylvin A Dias, Dermot F Brougham, Andreas Heise
Silicon wafers are decorated with photoamine generator 4,5-dimethoxy-2-nitrobenzyl 3-(triethoxysilyl)propyl carbamate. UV-irradiation in the presence of benzyl-l-glutamate N-carboxyanhydride is carried out, resulting in the release of the surface-bound primary amines, making them viable N-carboxyanhydride (NCA) polymerization initiators. Successful polypeptide grafting is confirmed by water contact angle measurements as well as by ellipsometry, revealing a poly(benzyl-l-glutamate) (PBLG) layer of ≈3 nm. X-ray photoelectron spectroscopy confirms the presence of amide groups in the grafted PBLG while time-of-flight secondary ion mass spectroscopy provides additional evidence for the presence of PBLG on the surface...
January 15, 2018: Macromolecular Rapid Communications
https://www.readbyqxmd.com/read/29333586/pre-operative-templating-for-knee-arthroplasty-shows-low-accuracy-with-standard-x-rays
#15
Nelson Hiroyuki Miyabe Ooka, André Luiz Siqueira Campos, Vitor Mudesto da Fonseca, Luis Edmundo Oliveira Rodrigues, Edmilson Barbosa Filho, José Sérgio Franco, Rodrigo Satamini Pires E Albuquerque, Vinicius Schott Gameiro
OBJECTIVES: The purpose of this study was to evaluate the accuracy and reliability of pre-operative templating in predicting the size of femoral and tibial components and the effect of coronal deformity on templating accuracy. METHODS: This was a retrospective study of 39 pre-operative templates prepared by three different surgeons with different levels of training. The accuracy and reliability measures were evaluated by alpha and kappa coefficients of agreement...
January 15, 2018: International Orthopaedics
https://www.readbyqxmd.com/read/29333524/resonant-x-ray-emission-of-hexagonal-boron-nitride
#16
John Vinson, Terrence Jach, Matthias Müller, Rainer Unterumsberger, Burkhard Beckhoff
The electronic structure of hexagonal boron nitride (h-BN) is explored using measurements of x-ray absorption and resonant inelastic x-ray scattering (RIXS) at the nitrogen K edge (1s) in tandem with calculations using many-body perturbation theory within the GW and Bethe-Salpeter equation (BSE) approximations. Our calculations include the effects of lattice disorder from phonons activated thermally and from zero point energy. They highlight the influence of disorder on near-edge x-ray spectra.
November 15, 2017: Physical Review. B
https://www.readbyqxmd.com/read/29333339/time-multiplexed-deep-reactive-ion-etching-of-germanium-and-silicon-a-comparison-of-mechanisms-and-application-to-x-ray-optics
#17
Vincent J Genova, David N Agyeman-Budu, Arthur R Woll
Although the mechanisms of deep reactive ion etching (DRIE) of silicon have been reported extensively, very little by comparison has been discussed concerning DRIE of germanium. By directly comparing silicon and germanium etching in a time multiplexed DRIE process, the authors extract significant differences in etch mechanisms from a design of experiment and discuss how these differences are relevant to the design and fabrication of silicon and germanium collimating channel array x-ray optics. The differences are illuminated by characteristics such as reactive ion etching (RIE)-lag, aspect ratio dependent etching, and sidewall passivation...
January 2018: Journal of Vacuum Science and Technology. B, Nanotechnology & Microelectronics: Materials, Processing, Measurement, & Phenomena: JVST B
https://www.readbyqxmd.com/read/29333330/amorphous-cobalt-vanadium-oxide-as-a-highly-active-electrocatalyst-for-oxygen-evolution
#18
Laurent Liardet, Xile Hu
The water-splitting reaction provides a promising mechanism to store renewable energies in the form of hydrogen fuel. The oxidation half-reaction, the oxygen evolution reaction (OER), is a complex four-electron process that constitutes an efficiency bottleneck in water splitting. Here we report a highly active OER catalyst, cobalt vanadium oxide. The catalyst is designed on the basis of a volcano plot of metal-OH bond strength and activity. The catalyst can be synthesized by a facile hydrothermal route. The most active pure-phase material (a-CoVO x ) is X-ray amorphous and provides a 10 mA cm-2 current density at an overpotential of 347 mV in 1 M KOH electrolyte when immobilized on a flat substrate...
January 5, 2018: ACS Catalysis
https://www.readbyqxmd.com/read/29333325/physicochemical-characterization-of-porcine-bone-derived-grafting-material-and-comparison-with-bovine-xenografts-for-dental-applications
#19
Jung Heon Lee, Gyu Sung Yi, Jin Woong Lee, Deug Joong Kim
Purpose: The physicochemical properties of a xenograft are very important because they strongly influence the bone regeneration capabilities of the graft material. Even though porcine xenografts have many advantages, only a few porcine xenografts are commercially available, and most of their physicochemical characteristics have yet to be reported. Thus, in this work we aimed to investigate the physicochemical characteristics of a porcine bone grafting material and compare them with those of 2 commercially available bovine xenografts to assess the potential of xenogenic porcine bone graft materials for dental applications...
December 2017: Journal of Periodontal & Implant Science
https://www.readbyqxmd.com/read/29333113/grating-oriented-line-wise-filtration-golf-for-dual-energy-x-ray-ct
#20
Yan Xi, Wenxiang Cong, Daniel Harrison, Ge Wang
In medical X-ray Computed Tomography (CT), the use of two distinct X-ray source spectra (energies) allows dose-reduction and material discrimination relative to that achieved with only one source spectrum. Existing dual-energy CT methods include source kVp-switching, double-layer detection, dual-source gantry, and two-pass scanning. Each method suffers either from strong spectral correlation or patient-motion artifacts. To simultaneously address these problems, we propose to improve CT data acquisition with the Grating Oriented Line-wise Filtration (GOLF) method, a novel X-ray filter that is placed between the source and patient...
December 2017: Sensing and Imaging
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