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X Bai, B Tie, J-H Schmitt, D Aubry
The correlation between ultrasonic wave propagation and polycrystalline microstructures has significant implications in nondestructive evaluation. An original numerical approach using the finite element method to quantify in both time and frequency domains the ultrasonic noise scattering due to the elastic heterogeneity of polycrystalline microstructures is presented. Based on the reciprocity theorem, it allows the scattering evaluation using mechanical data recorded only on the boundary of polycrystal instead of within its volume and is applicable to any polycrystalline aggregate regardless of its crystallographic or morphological characteristics...
February 14, 2018: Ultrasonics
Yun Bai, Chuan Liu, Lei Fu, Xiaoshan Gong, Ce Dou, Zhen Cao, Hongyu Quan, Jianmei Li, Fei Kang, Jingjin Dai, Chunrong Zhao, Shiwu Dong
Endochondral ossification is crucial for bone formation in both adult bone repair process and embryo long-bone development. In endochondral ossification, bone marrow-derived mesenchymal stem cells (BMSCs) first differentiate to chondrocyte, BMSC-derived chondrocyte then endure a hypertrophic process to generate new bone. Endochondral ossification-based bone repair is a promising strategy to cure massive bone defect, which is a major clinical issue in orthopedics. However, challenges still remain for this novel strategy...
March 16, 2018: FASEB Journal: Official Publication of the Federation of American Societies for Experimental Biology
Kurtis H Dekker, Rubin Hazarika, Matheus A Silveira, Kevin J Jordan
Optical cone beam computed tomography (CT) scanning of radiochromic gel dosimeters, using a CCD camera and a low stray light convergent source, provides fast, truly 3D radiation dosimetry with high accuracy. However, a key limiting factor in radiochromic gel dosimetry at large (⩾10 cm diameter) volumes is the initial attenuation of the dosimeters. It is not unusual to observe a 5-10×  difference in signal intensity through the dosimeter center versus through the surrounding medium in pre-irradiation images...
March 16, 2018: Physics in Medicine and Biology
Dimitar Popmintchev, Benjamin R Galloway, Ming-Chang Chen, Franklin Dollar, Christopher A Mancuso, Amelia Hankla, Luis Miaja-Avila, Galen O'Neil, Justin M Shaw, Guangyu Fan, Skirmantas Ališauskas, Giedrius Andriukaitis, Tadas Balčiunas, Oliver D Mücke, Audrius Pugzlys, Andrius Baltuška, Henry C Kapteyn, Tenio Popmintchev, Margaret M Murnane
Recent advances in high-order harmonic generation have made it possible to use a tabletop-scale setup to produce spatially and temporally coherent beams of light with bandwidth spanning 12 octaves, from the ultraviolet up to x-ray photon energies >1.6  keV. Here we demonstrate the use of this light for x-ray-absorption spectroscopy at the K- and L-absorption edges of solids at photon energies near 1 keV. We also report x-ray-absorption spectroscopy in the water window spectral region (284-543 eV) using a high flux high-order harmonic generation x-ray supercontinuum with 10^{9}  photons/s in 1% bandwidth, 3 orders of magnitude larger than has previously been possible using tabletop sources...
March 2, 2018: Physical Review Letters
Yongxi Ou, D C Ralph, R A Buhrman
Robust spin Hall effects (SHE) have recently been observed in nonmagnetic heavy metal systems with strong spin-orbit interactions. These SHE are either attributed to an intrinsic band-structure effect or to extrinsic spin-dependent scattering from impurities, namely, side jump or skew scattering. Here we report on an extraordinarily strong spin Hall effect, attributable to spin fluctuations, in ferromagnetic Fe_{x}Pt_{1-x} alloys near their Curie point, tunable with x. This results in a dampinglike spin-orbit torque being exerted on an adjacent ferromagnetic layer that is strongly temperature dependent in this transition region, with a peak value that indicates a lower bound 0...
March 2, 2018: Physical Review Letters
Ran Chen, Ying Lu, Zhiyong Jiang, Yongfeng Men
The poly(4-methyl-1-pentene) sample was used to investigate the cavitation induced stress-whitening phenomenon during stretching at different temperatures via the ultra-small-angle X-ray scattering technique. Two modes of cavitation were found that mode I cavitation activated around yield point followed by mode II cavitation generated in highly oriented state. The critical strain for initiating the mode II cavitation increases with the increase of stretching temperature whereas the critical stress grew steadily in the lower temperature regime (30~60oC) and reached a plateau at 70oC...
March 16, 2018: Journal of Physical Chemistry. B
Laura Castoldi, Laura Ielo, Wolfgang Holzer, Gerald Giester, Alexander Roller, Vittorio Pace
Primary and secondary α-halomethyl diazoketones generated via Arndt-Eistert chemistry with minimum loading of diazomethane efficiently alkylate aromatic amines in the presence of calcium oxide to furnish the corresponding α-arylamino diazoketones under full chemocontrol. Such a simple inorganic acid scavenger fully neutralizes the hydrohalic acid formed during the nucleophilic displacement which otherwise would immediately react to produce the corresponding α-haloketone. The methodology can be further exploited in analogous acylation-type processes on secondary arylamino diazoketones...
March 16, 2018: Journal of Organic Chemistry
Hari Babu Vasili, Matheus Gamino, Jaume Gazquez, Florencio Sanchez, Manuel Valvidares, Pierluigi Gargiani, Eric Pellegrin, Josep Fontcuberta
Pure spin currents hold promises for an energy-friendlier spintronics. They can be generated by a flow of charge along a non-magnetic metal having a large spin-orbit coupling. It produces a spin accumulation at its surfaces, controllable by the magnetization of an adjacent ferromagnetic layer. Paramagnetic metals typically used are close to a ferromagnetic instability and thus magnetic proximity effects can contribute to the observed angular-dependent magnetoresistance (ADMR). As interface phenomena govern the spin conductance across the metal/ferromagnetic-insulator heterostructures, unraveling these distinct contributions is pivotal to full understanding of spin current conductance...
March 16, 2018: ACS Applied Materials & Interfaces
Paween Mahinthichaichan, Robert B Gennis, Emad Tajkhorshid
Cytochrome aa3 is the terminal respiratory enzyme of all eukaryotes and many bacteria and archaea, reducing O2 to water and harnessing the free energy from the reaction to generate the transmembrane electrochemical potential. The diffusion of O2 to the heme-copper catalytic site, which is buried deep inside the enzyme, is the initiation step of the reaction chemistry. Our previous molecular dynamics (MD) study with cytochrome ba3 , a homologous enzyme of cytochrome aa3 in Thermus thermophilus, demonstrated that O2 diffuses from the lipid bilayer to its reduction site through a 25-Å long tunnel inferred by Xe-binding sites detected by X-ray crystallography$ ...
March 16, 2018: Biochemistry
D Liao, H Yu, L Han, C Zhong, X Ran, D Wang, L Mo
PURPOSE: Evidences showed that paraoxonase 1 (PON1) gene polymorphism has an impact on women's susceptibility to polycystic ovarian syndrome (PCOS) by influencing the expression and activity of PON1. However, the effects of three PON1 polymorphisms (- 108 C>T, L55M and Q192R) on the incidence of PCOS have generated inconsistent results. Here, we conducted a meta-analysis to investigate the association between PON1 polymorphisms and PCOS risk. METHODS: All eligible trials were identified via systematic searches of multiple literature databases...
March 15, 2018: Journal of Endocrinological Investigation
Juan A Santana, Nahyr A Lopez-Dauphin, Peter Beiersdorfer
Level energies are reported for Si V, Si VI, Si VII, Si VIII, Si IX, Si X, Si XI and Si XII. The energies have been calculated with the relativistic Multi-Reference Møller-Plesset Perturbation Theory method and include valence and K-vacancy states with nl up to 5 f . The accuracy of the calculated level energies is established by comparison with the recommended data listed in the National Institute of Standards and Technology (NIST) on-line database. The average deviation of valence level energies ranges from 0...
2018: Astrophysical Journal. Supplement Series
Franz X Bauer, Veronika Heinrich, Florian D Grill, Felix Wölfle, Dennis M Hedderich, Andrea Rau, Klaus-Dietrich Wolff, Lucas M Ritschl, Denys J Loeffelbein
Nasoalveolar Molding (NAM) is associated with ambivalent acceptance regarding effectiveness and unknown long-term results. Our purpose was to analyze the stress distribution patterns within the viscero- and neurocranium of neonates during the first phase of NAM therapy. A finite element (FE) model of a healthy four-week-old neonate was generated, derived from a computed tomography scan allowing the implementation of a bone-density-dependent material model. The influence of dental germs with variable material properties, the cleft width and area of expected force application were analyzed in a worst-case scenario...
February 2, 2018: Journal of Cranio-maxillo-facial Surgery
Qiang Wang, Feiyang Liu, Shuang Qi, Ziping Qi, Xiao-E Yan, Beilei Wang, Aoli Wang, Wei Wang, Cheng Chen, Xiaochuan Liu, Zongru Jiang, Zhenquan Hu, Li Wang, Wenchao Wang, Tao Ren, Shanchun Zhang, Cai-Hong Yun, Qingsong Liu, Jing Liu
Through exploration of the non-highly conserved allosteric hydrophobic pocket generated by DFG-out shifting in the inactive conformation, we discovered a highly selective type II PDGFRα kinase inhibitor 15i (CHMFL-PDGFRα-159), which exhibited strong potency against purified PDGFRα (IC50 : 132 nM) but not structurally similar PDGFRβ, ABL, c-KIT and VEGFR2 kinases. In addition, it displayed a high selectivity profile (S score (10) = 0.02) at the concentration of 1 μM among 468 kinases/mutants in the KINOMEscan profiling...
March 12, 2018: European Journal of Medicinal Chemistry
Katsuyuki Taguchi, Toshihide Itoh, Matthew K Fuld, Eric Fournie, Okkyun Lee, Kyo Noguchi
OBJECTIVES: A novel imaging technique ("X-map") has been developed to identify acute ischemic lesions for stroke patients using non-contrast-enhanced dual-energy computed tomography (NE-DE-CT). Using the 3-material decomposition technique, the original X-map ("X-map 1.0") eliminates fat and bone from the images, suppresses the gray matter (GM)-white matter (WM) tissue contrast, and makes signals of edema induced by severe ischemia easier to detect. The aim of this study was to address the following 2 problems with the X-map 1...
March 14, 2018: Investigative Radiology
Yong-Jun Xu, Hui Sheng, Tian-Wen Wu, Qing-Yue Bao, You Zheng, Yan-Min Zhang, Yu-Xiang Gong, Jian-Qiang Lu, Zhen-Dong You, Yang Xia, Xin Ni
Pregnant women at risk of preterm labor usually receive synthetic glucocorticoids (sGCs) to promote fetal lung development. Emerging evidence indicates that antenatal sGC increases the risk of affective disorders in offspring. Data from animal studies show that such disorders can be transmitted to the second generation. However, the molecular mechanisms underlying the intergenerational effects of prenatal sGC remain largely unknown. Here we show that prenatal dexamethasone (Dex) administration in late pregnancy induced depression-like behavior in first-generation (F1) offspring, which could be transmitted to second-generation (F2) offspring with maternal dependence...
March 15, 2018: FASEB Journal: Official Publication of the Federation of American Societies for Experimental Biology
Andreu Presa, Guillem Vázquez, Leoní A Barrios, Olivier Roubeau, Luís Korrodi-Gregório, Ricardo Pérez-Tomás, Patrick Gamez
The development of photoactivatable metal complexes with potential anticancer properties is a topical area of current investigation. Photoactivated chemotherapy using coordination compounds is typically based on photochemical processes occurring at the metal center. In the present study, an innovative approach is applied that takes advantage of the remarkable photochemical properties of diarylethenes. Following a proof-of-concept study with two complexes, namely, C1 and C2, a series of additional platinum(II) complexes from dithienylcyclopentene-based ligands was designed and prepared...
March 15, 2018: Inorganic Chemistry
Y Dargaud, X Delavenne, D P Hart, S Meunier, P Mismetti
Over the past decades, haemophilia management has continually evolved, with prophylaxis now considered the treatment of choice. Prophylaxis primarily seeks to prevent bleeding and haemarthrosis episodes from occurring and avert the otherwise inevitable haemophilic arthropathy. Yet, numerous unanswered issues remain. These concern dose levels, dosing intervals, ways of integrating variability in bleeding phenotype, patient age, joint status, lifestyle, physical activity, treatment adherence and individual responses to FVIII or FIX concentrates...
March 2018: Haemophilia: the Official Journal of the World Federation of Hemophilia
Ondřej Novák, Peter R Krogen, Tobias Kroh, Tomáš Mocek, Franz X Kärtner, Kyung-Han Hong
We report on a femtosecond ∼8.5  μm, ∼2  μJ source based on the intrapulse difference-frequency generation (DFG) of 2.1 μm pulses in an AgGaSe2 (AGSe) crystal. Compared to the conventional ∼0.8 or 1 μm near-infrared (IR) pulses, a ∼2  μm driver for intrapulse DFG can provide more efficient conversion into the wavelengths longer than 5 μm due to a lower quantum defect and is more suitable for the non-oxide nonlinear crystals that have a relatively low bandgap energy. Using 26 fs, 2...
March 15, 2018: Optics Letters
Zhaoxiang Liu, Jinping Yao, Jinming Chen, Bo Xu, Wei Chu, Ya Cheng
The generation of laserlike narrow bandwidth emissions from nitrogen molecular ions (N_{2}^{+}) generated in intense near- and mid infrared femtosecond laser fields has aroused much interest because of the mysterious physics underlying such a phenomenon. Here, we perform a pump-probe measurement on the nonlinear interaction of rotational quantum wave packets of N_{2}^{+} generated in midinfrared (e.g., at a wavelength centered at 1580 nm) femtosecond laser fields with an ultrashort probe pulse whose broad spectrum overlaps both P- and R-branch rotational transition lines between the electronic states N_{2}^{+}(B^{2}Σ_{u}^{+},v^{'}=0) and N_{2}^{+}(X^{2}Σ_{g}^{+},v=0)...
February 23, 2018: Physical Review Letters
Z H Zhong, R X Tang, M Zhou, X H Deng, Y Pang, W R Paterson, B L Giles, J L Burch, R B Tobert, R E Ergun, Y V Khotyaintsev, P-A Lindquist
Secondary flux ropes are suggested to play important roles in energy dissipation and particle acceleration during magnetic reconnection. However, their generation mechanism is not fully understood. In this Letter, we present the first direct evidence that a secondary flux rope was generated due to the evolution of an electron vortex, which was driven by the electron Kelvin-Helmholtz instability in an ion diffusion region as observed by the Magnetospheric Multiscale mission. The subion scale (less than the ion inertial length) flux rope was embedded within the electron vortex, which contained a secondary electron diffusion region at the trailing edge of the flux rope...
February 16, 2018: Physical Review Letters
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