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Giuseppe Fisicaro, Luigi Genovese, Oliviero Andreussi, Sagarmoy Mandal, Nisanth N Nair, Nicola Marzari, Stefan Goedecker
We present an implicit solvation approach where the interface between the quantum-mechanical solute and the surrounding environment is described by a fully continuous permittivity built up with atomic-centered ``soft'' spheres. This approach combines many of the advantages of the self-consistent continuum solvation model in handling solutes and surfaces in contact with complex dielectric environments or electrolytes in electronic-structure calculations. In addition it is able to describe accurately both neutral and charged systems...
June 19, 2017: Journal of Chemical Theory and Computation
Theodore Stenmark, R C Word, R Könenkamp
Using photoemission electron microscopy (PEEM) we present a comparative analysis of the wavelength dependence of propagating fields in a simple optical slab waveguide and a thin film photonic crystal W1-type waveguide. We utilize an interferometric imaging approach for light in the near-ultraviolet regime where a 2-photon process is required to produce photoelectron emission. The typical spatial resolution in these experiments is < 30nm. Electromagnetic theory and finite element simulations are shown to be in good agreement with the experimental observations...
June 13, 2017: Ultramicroscopy
Ingunn Risnes Hellings, Nils Ivar Dolvik, Stina Ekman, Kristin Olstad
Some epiphyseal growth cartilage canals are surrounded by a ring of hypereosinophilic matrix consisting of collagen type I. Absence of the collagen type I ring may predispose canal vessels to failure and osteochondrosis, which can lead to fragments in joints (osteochondrosis dissecans). It is not known whether the ring develops in response to programming or biomechanical force. The distribution that may reveal the function of the ring has only been described in the distal femur of a limited number of foals...
June 15, 2017: Journal of Anatomy
Melanie Rehage, Judith Delius, Thomas Hofmann, Matthias Hannig
OBJECTIVES: This electron microscopic study aimed at investigating effects of oral astringent stimuli on the enamel pellicle's morphology. METHODS: Pellicles were formed in situ within 30min on bovine enamel slabs, fixed to individuals' upper jaw splints. The pellicle-coated specimens were immersed in vitro in seven diverse astringent solutions and subsequently analyzed by scanning electron microscopy (SEM), energy dispersive X-ray (EDX) spectroscopy, as well as transmission electron microscopy (TEM)...
June 12, 2017: Journal of Dentistry
S A Piriz, A R Piriz, N A Tahir
A physical model has been developed for the linear Rayleigh-Taylor instability of a finite-thickness elastic slab laying on top of a semi-infinite ideal fluid. The model includes the nonideal effects of elasticity as boundary conditions at the top and bottom interfaces of the slab and also takes into account the finite transit time of the elastic waves across the slab thickness. For Atwood number A_{T}=1, the asymptotic growth rate is found to be in excellent agreement with the exact solution [Plohr and Sharp, Z...
May 2017: Physical Review. E
Kiyoung Kim, Eung Suk Kim, Yonguk Kim, Seung-Young Yu, Hyung Woo Kwak
PURPOSE: To investigate the correlation between preoperative en face spectral domain optical coherence tomography findings of the photoreceptor layer with restoration of foveal microstructure and visual acuity in repaired macular holes. METHODS: Medical records of 106 patients with surgically closed macular holes were retrospectively reviewed. Preoperative OCT slabs of the external limiting membrane (ELM) and ellipsoid zone (EZ) were generated using embedded tools...
May 22, 2017: Retina
Chunxian Tao, Bo Yang, Zhenqing Li, Dawei Zhang, Yoshinori Yamaguchi
Slab gel electrophoresis (SGE) is the most common method for the separation of DNA fragments; thus, it is broadly applied to the field of biology and others. However, the traditional SGE protocol is quite tedious, and the experiment takes a long time. Moreover, the chemical consumption in SGE experiments is very high. This work proposes a simple method for the separation of DNA fragments based on an SGE chip. The chip is made by an engraving machine. Two plastic sheets are used for the excitation and emission wavelengths of the optical signal...
June 1, 2017: Journal of Visualized Experiments: JoVE
Mohsin Ali, Mansoor Ahmed, Shakil Ahmed, Syed Imran Ali, Samina Perveen, Majid Mumtaz, Syed Moazzam Haider, Urooj Nazim
The human digestive tract contains some 100 trillion cells and thousands of species of micro-organisms may be present as normal flora of this tract as well as other mucocutaneous junctions of the body. Candida specie is the most common organism residing in these areas and can easily invade the internal tissues in cases of loss of host defenses. Modifications of previously existing antifungal agents may provide new options to fight against these species. Inorganic compounds of different antifungals are under investigations...
January 2017: Pakistan Journal of Pharmaceutical Sciences
Minoru Sayou, Ryosuke Ishizuka, Nobuyuki Matubayasi
Adsorption and absorption were analyzed for nonpolar and polar solutes to a water droplet of nanometer size and to a planar slab. All-atom molecular dynamics simulation was performed, and the free energy change for bringing the solute to the water aggregate was computed over a wide range of temperature. It was seen in both the droplet and slab systems that the solute is preferably located at the surface, and the propensity of the nonpolar solute at the surface relative to the bulk was found to be larger in the droplet than in the slab...
June 9, 2017: Journal of Physical Chemistry. B
Angela D Morris, Alev Erisir, Stacey J Criswell, Sarah Kucenas
BACKGROUND: Spinal motor nerves are essential for relaying information between the central and peripheral nervous systems. Perturbations to cell types that compose these nerves may impair rapid and efficient transmission of action potentials and alter nerve function. Identifying ultrastructural changes resulting from defects to these cellular components via transmission electron microscopy (TEM) can provide valuable insight into nerve function and disease. However, efficiently locating spinal motor nerves in adult zebrafish for TEM is challenging and time consuming...
June 9, 2017: Developmental Dynamics: An Official Publication of the American Association of Anatomists
Michael Z Hu, David W DePaoli, Tanya Kuritz, Ogbemi O Omatete
We present a "bottom-up" fabrication approach to first grow a new class of inorganic (silica) long hair-like microfibrils or microwires and then to form monolithic solid pellet that contains parallel arrays of bundled microfibrils with a controlled orientation. During the sol-gel solution processing, reactive precursor species are utilized as molecular "building blocks" for the field-directed assembly growth of microfibrils driven by an electric field of pulsed direct current (dc) with controlled frequency...
April 20, 2017: Recent Patents on Nanotechnology
Zhao-Hua Lu, Sy-Miin Chow, Eric Loken
We compare the performances of well-known frequentist model fit indices (MFIs) and several Bayesian model selection criteria (MCC) as tools for cross-loading selection in factor analysis under low to moderate sample sizes, cross-loading sizes, and possible violations of distributional assumptions. The Bayesian criteria considered include the Bayes factor (BF), Bayesian Information Criterion (BIC), Deviance Information Criterion (DIC), a Bayesian leave-one-out with Pareto smoothed importance sampling (LOO-PSIS), and a Bayesian variable selection method using the spike-and-slab prior (SSP; Lu, Chow, & Loken, 2016)...
June 2017: Psychological Methods
James Clark Field, Paula Jane Waterhouse, Matthew John German
AIM: This study aimed to test the null hypothesis that there are no significant differences in surface characteristics of eroded and abraded human, ovine and bovine enamel. DESIGN: Twenty enamel slabs were prepared from bovine, human and ovine incisor crowns, and randomly assigned to one of 4 treatments: 30 second/4 minute immersion at 1%/6% w/v citric acid. Post-erosion, an oscillatory brush was used for 20 seconds. Roughness parameters, height change and scanning electron microscopy were measured at each stage...
June 2017: European Journal of Prosthodontics and Restorative Dentistry
Stefano Peca, Derek Wilson Brown, Wendy Lani Smith
PURPOSE: To improve patient safety and treatment quality, verification of dose delivery in radiotherapy is desirable. We present a simple, easy-to-implement, open-source method for in vivo planar dosimetry of conformal radiotherapy by electronic portal imaging device (EPID). METHODS: Correlation ratios, which relate dose in the mid-depth of slab phantoms to transit EPID signal, were determined for multiple phantom thicknesses and field sizes. Off-axis dose is corrected for by means of model-based convolution...
January 1, 2017: Technology in Cancer Research & Treatment
T Kimura, H Ohfuji, M Nishi, T Irifune
Periclase (MgO) is the second most abundant mineral after bridgmanite in the Earth's lower mantle, and its melting behaviour under pressure is important to constrain rheological properties and melting behaviours of the lower mantle materials. Significant discrepancies exist between the melting temperatures of MgO determined by laser-heated diamond anvil cell (LHDAC) and those based on dynamic compressions and theoretical predictions. Here we show the melting temperatures in earlier LHDAC experiments are underestimated due to misjudgment of melting, based on micro-texture observations of the quenched samples...
June 5, 2017: Nature Communications
A V S Ponnaluri, L E Perotti, D B Ennis, W S Klug
We present a constitutive modeling framework for contractile cardiac mechanics by formulating a single variational principle from which incremental stress-strain relations and kinetic rate equations for active contraction and relaxation can all be derived. The variational framework seamlessly incorporates the hyperelastic behavior of the relaxed and contracted tissue along with the rate - and length - dependent generation of contractile force. We describe a three-element, Hill-type model that unifies the active tension and active deformation approaches...
February 1, 2017: Computer Methods in Applied Mechanics and Engineering
Zhengping Ding, Mingquan Xu, Jiatu Liu, Qun Huang, Libao Chen, Peng Wang, Douglas G Ivey, Weifeng Wei
Although chemical doping has been extensively employed to improve the electrochemical performance of Li-rich layered oxide (LLO) cathodes for Li ion batteries, the correlation between the electrochemical kinetics and local structure and chemistry of these materials after chemical doping is still not fully understood. Herein, gradient surface Si/Sn-doped LLOs with improved kinetics are demonstrated. The atomic local structure and surface chemistry are determined using electron microscopy and spectroscopy techniques, and remarkably, the correlation of local structure-enhanced kinetics is clearly described in this work...
June 21, 2017: ACS Applied Materials & Interfaces
Ayan Mitra, David G Politte, Bruce R Whiting, Jeffrey F Williamson, Joseph A O'Sullivan
Model-based image reconstruction (MBIR) techniques have the potential to generate high quality images from noisy measurements and a small number of projections which can reduce the x-ray dose in patients. These MBIR techniques rely on projection and backprojection to refine an image estimate. One of the widely used projectors for these modern MBIR based technique is called branchless distance driven (DD) projection and backprojection. While this method produces superior quality images, the computational cost of iterative updates keeps it from being ubiquitous in clinical applications...
January 2017: Journal of Imaging Science and Technology
Jian Wang, Dapeng Zhao, Zhenxing Yao
It has been proposed that dehydration embrittlement of hydrous materials can trigger intermediate-depth earthquakes and form a double seismic zone in a subducting slab. Seismic anisotropy may provide a possible insight into intermediate-depth intraslab seismicity, because anisotropic properties of minerals change with varying water distribution, temperature and pressure. Here we present a high-resolution model of P-wave radial anisotropy tomography of the Japan subduction zone down to ~400 km depth, which is obtained using a large number of arrival-time data of local earthquakes and teleseismic events...
June 1, 2017: Scientific Reports
Marie-Luise Braatz, Leslie Infantas Meléndez, Michele Sferrazza, Simone Napolitano
We investigated the impact of irreversible adsorption on the mechanisms of thermal expansion of 1D confined polymer layers. For spincoated films (polystyrene on aluminum) of constant thickness, the thermal expansion coefficient of the melt drops upon annealing following the kinetics of irreversible adsorption of the chains onto the supporting substrate, while the thermal expansion of the glass is annealing invariant. These perturbations are explained in terms of the reduction in free volume content, upon immobilization of monomers onto the substrate...
May 28, 2017: Journal of Chemical Physics
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