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Khosrow Shakouri, Jörg Behler, Joerg Meyer, Geert-Jan Kroes
Ab initio molecular dynamics (AIMD) simulations enable the accurate description of reactive molecule-surface scattering especially if energy transfer involving surface phonons is important. However, presently the computational expense of AIMD rules out its application to systems where reaction probabilities are smaller than about 1 percent. Here we show that this problem can be overcome by a high-dimensional neural network fit of the molecule-surface interaction potential, which also incorporates the dependence on phonons by taking into account all degrees of freedom of the surface explicitly...
April 25, 2017: Journal of Physical Chemistry Letters
Ran Peng, Dongqing Li
The RPS (Resistive Pulse Sensing) technique is a popular tool for the label-free detection of particles. This paper describes a simple, cost-effective PDMS nanofluidic chip for the detection and characterization of nanoparticles based on the differential RPS technique with high resolution and sensitivity. The chip is composed of two layers of PDMS slabs. Microchannel systems fabricated by the photolithography method on the top layer are used for sample loading and differential signal acquisition, and a straight nanochannel on the bottom layer fabricated by an unconventional approach bridging the gap between the microchannels works as an RPS sensing gate...
April 25, 2017: Nanoscale
Marco Costantini, Stefano Testa, Ersilia Fornetti, Andrea Barbetta, Marcella Trombetta, Stefano Maria Cannata, Cesare Gargioli, Alberto Rainer
In this work, the influence of mechanical stiffness and geometrical confinement on the 3D culture of myoblast-laden gelatin methacryloyl (GelMA) photo-crosslinkable hydrogels was evaluated in terms of in vitro myogenesis. We formulated a set of cell-laden GelMA hydrogels with a compressive modulus in the range 1 ÷ 17 kPa, obtained by varying GelMA concentration and degree of cross-linking. C2C12 myoblasts were chosen as the cell model to investigate the supportiveness of different GelMA hydrogels toward myotube formation up to 2 weeks...
2017: Frontiers in Bioengineering and Biotechnology
Sune G Nielsen, Horst R Marschall
In subduction zones, sediments and hydrothermally altered oceanic crust, which together form part of the subducting slab, contribute to the chemical composition of lavas erupted at the surface to form volcanic arcs. Transport of this material from the slab to the overlying mantle wedge is thought to involve discreet melts and fluids that are released from various portions of the slab. We use a meta-analysis of geochemical data from eight globally representative arcs to show that melts and fluids from individual slab components cannot be responsible for the formation of arc lavas...
April 2017: Science Advances
Berkin Bilgic, Huihui Ye, Lawrence L Wald, Kawin Setsompop
T2⁎ weighted 3D Gradient Echo (GRE) acquisition is the main sequence used for Susceptibility Weighted Imaging (SWI) and Quantitative Susceptibility Mapping (QSM). These applications require a long echo time (TE) to build up phase contrast, requiring a long repetition time (TR), and leading to excessively lengthy scans. The long TE acquisition creates a significant amount of unused time within each TR, which can be utilized for either multi-echo sampling or additional image encoding with the echo-shift technique...
April 20, 2017: NeuroImage
Chuan Guo, Junwei Zuo, Qi Bian, Chang Xu, Qinshuang Zong, Yong Bo, Yu Shen, Nan Zong, Hongwei Gao, Yanyong Lin, Lei Yuan, Yang Liu, Dafu Cui, Qinjun Peng, Zuyan Xu
We demonstrate a compact, high-power, quasi-continuous-wave (QCW) end-pumped 1319 nm Nd:YAG slab amplifier laser with good beam quality. The laser is based on a QCW pulse Nd:YAG master oscillator and Nd:YAG slab amplifier with multi-pass zigzag architecture. The amplifier operates at a pulse repetition frequency of 500 Hz and pulse width of ∼105  μs, delivering a maximum output power of 51.5 W under absorbed pump power of 217.8 W and corresponding to an extraction efficiency of 14.2%. The beam quality factor is measured to be Mx2=1...
April 20, 2017: Applied Optics
Ludwig Gutzweiler, Tobias Gleichmann, Laurent Tanguy, Peter Koltay, Roland Zengerle, Lutz Riegger
Gel electrophoresis is one of the most applied and standardized tools for separation and analysis of macromolecules and their fragments in academic research and in industry. In this work we present a novel approach for conducting on-demand electrophoretic separations of DNA molecules in open microfluidic (OM) systems on planar polymer substrates. The approach combines advantages of slab gel, capillary- & chip-based methods offering low consumable costs (<0.1 $) circumventing cost intensive microfluidic chip fabrication, short process times (5 minutes per analysis) and high sensitivity (4 ng/μl dsDNA) combined with reasonable resolution (17 bases)...
April 20, 2017: Electrophoresis
Henrik Johansson, Miriam von Tiedemann, Klaus Erhard, Harald Heese, Huanjun Ding, Sabee Molloi, Erik Fredenberg
PURPOSE: To evaluate a method for measuring breast density using photon-counting spectral mammography. Breast density is an indicator of breast cancer risk and diagnostic accuracy in mammography, and can be used as input to personalized screening, treatment monitoring and dose estimation. METHODS: The measurement method employs the spectral difference in x-ray attenuation between adipose and fibro-glandular tissue, and does not rely on any a-priori information. The method was evaluated using phantom measurements on tissue-equivalent material (slabs and breast-shaped phantoms) and using clinical data from a screening population (n=1329)...
April 19, 2017: Medical Physics
Susie Lau, Yang Faridah Abdul Aziz, Kwan Hoong Ng
OBJECTIVES: To investigate: (1) the variability of mammographic compression parameters amongst Asian women; and (2) the effects of reducing compression force on image quality and mean glandular dose (MGD) in Asian women based on phantom study. METHODS: We retrospectively collected 15818 raw digital mammograms from 3772 Asian women aged 35-80 years who underwent screening or diagnostic mammography between Jan 2012 and Dec 2014 at our center. The mammograms were processed using a volumetric breast density (VBD) measurement software (Volpara) to assess compression force, compression pressure, compressed breast thickness (CBT), breast volume, VBD and MGD against breast contact area...
2017: PloS One
Andrey A Kuznetsov, Alexander F Pshenichnikov
Langevin dynamics simulation is used to study the suspension of interacting magnetic nanoparticles (dipolar spheres) in a zero applied magnetic field and in the presence of a gravitational (centrifugal) field. A particular emphasis is placed on the equilibrium vertical distribution of particles in the infinite horizontal slab. An increase in the dipolar coupling constant λ (the ratio of dipole-dipole interaction energy to thermal energy) from zero to seven units causes an increase in the particle segregation coefficient by several orders of magnitude...
March 2017: Physical Review. E
Antoine M Klauser, Oliver T Wiebenga, Anand Jc Eijlers, Menno M Schoonheim, Bernard Mj Uitdehaag, Frederik Barkhof, Petra Jw Pouwels, Jeroen Jg Geurts
BACKGROUND: Multiple sclerosis is characterized by white matter lesions, which are visualized with conventional T2-weighted magnetic resonance imaging (MRI). Little is known about local metabolic processes preceding the appearance and during the pathological development of new lesions. OBJECTIVE: To identify metabolite changes preceding white matter (WM) lesions and pathological severity of lesions over time. METHODS: A total of 59 relapsing-remitting multiple sclerosis (MS) patients were scanned four times, with 6-month intervals...
April 1, 2017: Multiple Sclerosis: Clinical and Laboratory Research
Oliver Plümper, Helen E King, Thorsten Geisler, Yang Liu, Sonja Pabst, Ivan P Savov, Detlef Rost, Thomas Zack
Serpentinization-fueled systems in the cool, hydrated forearc mantle of subduction zones may provide an environment that supports deep chemolithoautotrophic life. Here, we examine serpentinite clasts expelled from mud volcanoes above the Izu-Bonin-Mariana subduction zone forearc (Pacific Ocean) that contain complex organic matter and nanosized Ni-Fe alloys. Using time-of-flight secondary ion mass spectrometry and Raman spectroscopy, we determined that the organic matter consists of a mixture of aliphatic and aromatic compounds and functional groups such as amides...
April 10, 2017: Proceedings of the National Academy of Sciences of the United States of America
Naoki Matsuda, Hirotaka Okabe, Ayako Omura, Miki Nakano, Koji Miyake
To immobilize cytochrome c (cyt.c) on an ITO electrode while keeping its direct electron transfer (DET) functionality, the ITO electrode surface was modified with 11-{2-[2-(2-methoxyethoxy)ethoxy]ethoxy}undecylphosphonic acid (CH3O (CH2CH2O)3C11H22PO(OH)2, M-EG3-UPA) self-assembled monolayer (SAM) film. After a 100-times washing process to exchange a phosphate buffer saline solution surrounding cyt.c and ITO electrode to a fresh one, an in situ observation of visible absorption spectral change with slab optical waveguide (SOWG) spectroscopy showed that 87...
2017: Analytical Sciences: the International Journal of the Japan Society for Analytical Chemistry
Shinya Taguchi, Hirofumi Kawazumi, Toshihiko Nagamura, Hirotaka Okabe, Naoki Matsuda
An automated solution exchange (SE) mechanism has been introduced to slab optical waveguide spectroscopy to estimate the protein immobilizing ability of a slab optical waveguide (SOWG) surface. In each SE process, SOWG spectral change in absorbance at peak position of cytochrome c (cyt.c) Soret band at 409 nm was observed to analyze the desorption ratio of cyt.c adsorbed on SOWG surface. Continuous SE processes for 100 times have successfully brought us a kind of master desorption curve of cyt.c, which was well fitted by a double exponential equation, indicating the existence of three kinds of adsorbed states, including weakly adsorbed, strongly adsorbed, and immobilized cyt...
2017: Analytical Sciences: the International Journal of the Japan Society for Analytical Chemistry
Lara Maria Herrera, Clemente Maia da Silva Fernandes, Mônica da Costa Serra
This study aimed to develop and to assess an algorithm to facilitate lip print visualization, and to digitally analyze lip prints on different supports, by superimposition. It also aimed to classify lip prints according to sex. A batch image processing algorithm was developed, which facilitated the identification and extraction of information about lip grooves. However, it performed better for lip print images with a uniform background. Paper and glass slab allowed more correct identifications than glass and the both sides of compact disks...
April 6, 2017: Journal of Forensic Sciences
Barbara Eicher, Frederick A Heberle, Drew Marquardt, Gerald N Rechberger, John Katsaras, Georg Pabst
Low- and high-resolution models describing the internal transbilayer structure of asymmetric lipid vesicles have been developed. These models can be used for the joint analysis of small-angle neutron and X-ray scattering data. The models describe the underlying scattering length density/electron density profiles either in terms of slabs or through the so-called scattering density profile, previously applied to symmetric lipid vesicles. Both models yield structural details of asymmetric membranes, such as the individual area per lipid, and the hydrocarbon thickness of the inner and outer bilayer leaflets...
April 1, 2017: Journal of Applied Crystallography
Hua Zhao, Yince Wang, Tingyu Xue, Hang Su, Jingwen Zhang
An iron-doped Y-cut lithium niobate (Fe:LN) slab was coated with indium-tin-oxide (ITO) thin films by magnetron sputtering. The electron confinement in a sub-nanometer region at ITO/LN interfaces is resulted from electric screening effect. Consequently, the local plasma frequency in the sub-nanometer metallic-like layer is shifted to the UV regime. This makes it possible to excite surface plasmon polaritons (SPPs) in the visible region with photorefractive phase gratings in the LN slab and to transport SPPs much energy-efficiently...
March 20, 2017: Optics Express
Liangfu Ni, Jicheng Jin, Chao Peng, Zhengbin Li
We extend the coupled-wave-theory (CWT) framework to a supercell lattice photonic crystal (PC) structure to model the radiation of high-Q resonances under structural fluctuations since they are inevitable in realistic devices. The comparison of CWT results and the finite-element-method (FEM) simulations confirm the validity of CWT. It is proved that the supercell model approaches a realistic finite-size PC device when the supercell size is large enough. The Q factors within fluctuated structures are constraint owing to the appearance of fractional orders of radiative waves, which are induced by structural fluctuations...
March 6, 2017: Optics Express
Narayan Mohanta, Arno P Kampf, Thilo Kopp
The quantum anomalous Hall effect has been theoretically predicted and experimentally verified in magnetic topological insulators. In addition, the surface states of these materials exhibit a hedgehoglike "spin" texture in momentum space. Here, we apply the previously formulated low-energy model for Bi2Se3, a parent compound for magnetic topological insulators, to a slab geometry in which an exchange field acts only within one of the surface layers. In this sample set up, the hedgehog transforms into a skyrmion texture beyond a critical exchange field...
April 5, 2017: Scientific Reports
Chokri Issaoui, Hammouda Chebbi, Abderrahmen Guesmi
To investigate the influence of P/As substitution on structures and electrical properties, e.g. the effect on material densities, two new solid P/As-doped solutions, Na2CoP1.60As0.40O7 (disodium cobalt diphosphorus arsenic heptaoxide) and Na2CoP1.07As0.93O7 (disodium cobalt phosphorus arsenic heptaoxide), with melilite-like structures have been synthesized by solid-state reactions. Their unit-cell parameters are in agreement with Vegard's law. The obtained structural models were investigated by the bond valence sum (BVS) and charge distribution (CHARDI) validation tools and, for the latter, the structures are described as being built on anion-centred polyhedra...
April 1, 2017: Acta Crystallographica. Section C, Structural Chemistry
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