bluuebunny/crossref_metadata_2025 huggingface dataset:
Role of weakly bound complexes in temperature-dependence and relative rates of MxOy− + H2O (M = Mo, W) reactions
Authors: Kafader Jared O. , Ray Manisha , Raghavachari Krishnan , Jarrold Caroline Chick
Published: February 2016

Results of a systematic comparison of the MoxOy− + H2O and WxOy− + H2O reaction rate coefficients are reported and compared to previous experimental and computational studies on these reactions. WxOy− clusters undergo more direct oxidation by water to yield WxOy+1− + H2, while for MoxOy− clusters, production of MoxOyH2− (trapped intermediates in the oxidation reaction) is comparatively more prevalent. However, MoxOy− clusters generally have higher rate coefficients than analogous WxOy− clusters if MoxOy+1H2− formation is included. Results of calculations on the M2Oy− + H2O (M = Mo, W; y = 4, 5) reaction entrance channel are reported. They include charge-dipole complexes formed from long-range interactions, and the requisite conversion to a Lewis acid-base complex that leads to MxOy+1H2− formation. The results predict that the Lewis acid-base complex is more strongly bound for MoxOy− clusters than for WxOy− clusters. The calculated free energies along this portion of the reaction path are also consistent with the modest anti-Arrhenius temperature dependence measured for most MoxOy− + H2O reactions, and the WxOy− + H2O reaction rate coefficients generally being constant over the temperature range sampled in this study. For clusters that exhibit evidence of both water addition and oxidation reactions, increasing the temperature increases the branching ratio toward oxidation for both species. A more direct reaction path to H2 production may therefore become accessible at modest temperatures for certain cluster stoichiometries and structures.
All-solid-state deep ultraviolet laser for single-photon ionization mass spectrometry
Authors: Yuan Chengqian , Liu Xianhu , Zeng Chenghui , Zhang Hanyu , Jia Meiye , Wu Yishi , Luo Zhixun , Fu Hongbing , Yao Jiannian
Published: February 2016

We report here the development of a reflectron time-of-flight mass spectrometer utilizing single-photon ionization based on an all-solid-state deep ultraviolet (DUV) laser system. The DUV laser was achieved from the second harmonic generation using a novel nonlinear optical crystal KBe2BO3F2 under the condition of high-purity N2 purging. The unique property of this laser system (177.3-nm wavelength, 15.5-ps pulse duration, and small pulse energy at ∼15 μJ) bears a transient low power density but a high single-photon energy up to 7 eV, allowing for ionization of chemicals, especially organic compounds free of fragmentation. Taking this advantage, we have designed both pulsed nanospray and thermal evaporation sources to form supersonic expansion molecular beams for DUV single-photon ionization mass spectrometry (DUV-SPI-MS). Several aromatic amine compounds have been tested revealing the fragmentation-free performance of the DUV-SPI-MS instrument, enabling applications to identify chemicals from an unknown mixture.
Tracking the photodissociation probability of D2+ induced by linearly chirped laser pulses
Authors: Csehi András , Halász Gábor J. , Cederbaum Lorenz S. , Vibók Ágnes
Published: February 2016

In the presence of linearly varying frequency chirped laser pulses, the photodissociation dynamics of D2+ is studied theoretically after ionization of D2. As a completion of our recent work [A. Csehi et al., J. Chem. Phys. 143, 014305 (2015)], a comprehensive dependence on the pulse duration and delay time is presented in terms of total dissociation probabilities. Our numerical analysis carried out in the recently introduced light-induced conical intersection (LICI) framework clearly shows the effects of the changing position of the LICI which is induced by the frequency modulation of the chirped laser pulses. This impact is presented for positively, negatively, and zero chirped short pulses.
Enstrophy production and dissipation in developing grid-generated turbulence
Authors: Zhou Yi , Nagata Koji , Sakai Yasuhiko , Ito Yasumasa , Hayase Toshiyuki
Published: February 2016

Direct numerical simulations are performed to investigate the spatial evolution of small-scale motions in turbulence behind a single square grid. Some aspects of small-scale motions, which are thought to be universal, are examined at different streamwise locations along the centerline. The behavior of small-scale motions at the end of the simulation region resembles the well-known behavior observed in many types of turbulence (e.g., homogeneous isotropic turbulence, fractal-generated turbulence, and plane jet), whereas in the near grid region, the turbulence exhibits quite different properties. For instance, the alignments between the vortex vector and the eigenvectors are relatively weak in the upstream location. In contrast, at the furthermost downstream location, the alignments are close to the case of homogeneous isotropic turbulence. Also, it is demonstrated that the high enstrophy region may not be indispensable for the appearance of the 2/3 power-law at a streamwise location close to the grid.
Stabilization of the hypersonic boundary layer by finite-amplitude streaks
Authors: Ren Jie , Fu Song , Hanifi Ardeshir
Published: February 2016

Stabilization of two-dimensional disturbances in hypersonic boundary layer flows by finite-amplitude streaks is investigated using nonlinear parabolized stability equations. The boundary-layer flows at Mach numbers 4.5 and 6.0 are studied in which both first and second modes are supported. The streaks considered here are driven either by the so-called optimal perturbations (Klebanoff-type) or the centrifugal instability (Görtler-type). When the streak amplitude is in an appropriate range, i.e., large enough to modulate the laminar boundary layer but low enough to not trigger secondary instability, both first and second modes can effectively be suppressed.
Role of the sample thickness on the performance of cholesteric liquid crystal lasers: Experimental, numerical, and analytical results
Authors: Sanz-Enguita G. , Ortega J. , Folcia C. L. , Aramburu I. , Etxebarria J.
Published: February 2016

We have studied the performance characteristics of a dye-doped cholesteric liquid crystal (CLC) laser as a function of the sample thickness. The study has been carried out both from the experimental and theoretical points of view. The theoretical model is based on the kinetic equations for the population of the excited states of the dye and for the power of light generated within the laser cavity. From the equations, the threshold pump radiation energy Eth and the slope efficiency η are numerically calculated. Eth is rather insensitive to thickness changes, except for small thicknesses. In comparison, η shows a much more pronounced variation, exhibiting a maximum that determines the sample thickness for optimum laser performance. The predictions are in good accordance with the experimental results. Approximate analytical expressions for Eth and η as a function of the physical characteristics of the CLC laser are also proposed. These expressions present an excellent agreement with the numerical calculations. Finally, we comment on the general features of CLC layer and dye that lead to the best laser performance.
Measurement of thermal conductivity of Bi2Te3 nanowire using high-vacuum scanning thermal wave microscopy
Authors: Park Kyungbae , Hwang Gwangseok , Kim Hayeong , Kim Jungwon , Kim Woochul , Kim Sungjin , Kwon Ohmyoung
Published: February 2016

With the increasing application of nanomaterials in the development of high-efficiency thermoelectric energy conversion materials and electronic devices, the measurement of the intrinsic thermal conductivity of nanomaterials in the form of nanowires and nanofilms has become very important. However, the current widely used methods for measuring thermal conductivity have difficulties in eliminating the influence of interfacial thermal resistance (ITR) during the measurement. In this study, by using high-vacuum scanning thermal wave microscopy (HV-STWM), we propose a quantitative method for measuring the thermal conductivity of nanomaterials. By measuring the local phase lag of high-frequency (>10 kHz) thermal waves passing through a nanomaterial in a high-vacuum environment, HV-STWM eliminates the measurement errors due to ITR and the distortion due to heat transfer through air. By using HV-STWM, we measure the thermal conductivity of a Bi2Te3 nanowire. Because HV-STWM is quantitatively accurate and its specimen preparation is easier than in the thermal bridge method, we believe that HV-STWM will be widely used for measuring the thermal properties of various types of nanomaterials.
Holographic quantization of gravity in a black hole background
Authors: Park I. Y.
Published: February 2016

It was recently observed in Park [Eur. Phys. J. C (unpublished); e-print arXiv:1404.5066 [hep-th]] that the holographic nature of gravity may hold a key to quantization of gravity. The so-called “holographic quantization” has been carried out in Park [J. High Energy Phys. 1504, 053 (2015); e-print arXiv:1412.1528 [hep-th]; e-print arXiv:1506.08383 [hep-th]] for Einstein gravity in a flat background. Generalizing the procedure to a curved background is the main goal of the present work. In particular, we consider the Einstein action expanded around a Schwarzschild background.
Anisotropic electronic, mechanical, and optical properties of monolayer WTe2
Authors: Torun E. , Sahin H. , Cahangirov S. , Rubio A. , Peeters F. M.
Published: February 2016

Using first-principles calculations, we investigate the electronic, mechanical, and optical properties of monolayer WTe2. Atomic structure and ground state properties of monolayer WTe2 (Td phase) are anisotropic which are in contrast to similar monolayer crystals of transition metal dichalcogenides, such as MoS2, WS2, MoSe2, WSe2, and MoTe2, which crystallize in the H-phase. We find that the Poisson ratio and the in-plane stiffness is direction dependent due to the symmetry breaking induced by the dimerization of the W atoms along one of the lattice directions of the compound. Since the semimetallic behavior of the Td phase originates from this W-W interaction (along the a crystallographic direction), tensile strain along the dimer direction leads to a semimetal to semiconductor transition after 1% strain. By solving the Bethe-Salpeter equation on top of single shot G0W0 calculations, we predict that the absorption spectrum of Td-WTe2 monolayer is strongly direction dependent and tunable by tensile strain.
Modelling of the Peltier effect in magnetic multilayers
Authors: Juarez-Acosta Isaac , Olivares-Robles Miguel A. , Bosu Subrojati , Sakuraba Yuya , Kubota Takahide , Takahashi Saburo , Takanashi Koki , Bauer Gerrit E. W.
Published: February 2016

We model the charge, spin, and heat currents in ferromagnetic metal|normal metal|normal metal trilayer structures in the two current model, taking into account bulk and interface thermoelectric properties as well as Joule heating. The results include the temperature distribution as well as resistance-current curves that reproduce the observed shifted parabolic characteristics. Thin tunneling barriers can enhance the apparent Peltier cooling. The model agrees with the experimental results for wide multilayer pillars, but the giant effects observed for diameters ≲100 nm are still under discussion.
Investigation of helium plasma temperature in atmospheric-pressure plasma plume using line pair method
Authors: Yambe Kiyoyuki , Satou Sou
Published: February 2016

We have studied the atmospheric pressure plasma generated using a quartz tube, helium gas, and foil electrode by applying AC high voltage. The plasma plume is released into the atmosphere from inside the quartz tube. The helium plasma temperature is investigated using a line pair method. The excitation temperature of the electrons in the helium plasma is estimated at about 700 K along the plasma plume (column). The excitation temperature of the electrons decreases slightly towards the tip of the plasma plume. Because the emitted light of the helium ion (He I) excitation at a wavelength of 706 nm is weak at the tip of the plasma plume, the electron excitation temperature is overestimated. In the atmosphere region near the tip of the plasma plume, collisions between helium gas and air increase. Therefore, the electron excitation temperature determined using the observed emitted light from helium ion excitation inside of the quartz tube filled with a helium gas.
Limiting current of intense electron beams in a decelerating gap
Authors: Nusinovich G. S. , Beaudoin B. L. , Thompson C. , Karakkad J. A. , Antonsen T. M.
Published: February 2016

For numerous applications, it is desirable to develop electron beam driven efficient sources of electromagnetic radiation that are capable of producing the required power at beam voltages as low as possible. This trend is limited by space charge effects that cause the reduction of electron kinetic energy and can lead to electron reflection. So far, this effect was analyzed for intense beams propagating in uniform metallic pipes. In the present study, the limiting currents of intense electron beams are analyzed for the case of beam propagation in the tubes with gaps. A general treatment is illustrated by an example evaluating the limiting current in a high-power, tunable 1–10 MHz inductive output tube (IOT), which is currently under development for ionospheric modification. Results of the analytical theory are compared to results of numerical simulations. The results obtained allow one to estimate the interaction efficiency of IOTs.
Microfluidic synthesis of multiferroic Janus particles with disk-like compartments
Authors: Yu Xiaolei , Zhang Cancan , You Sujian , Liu Huiqin , Zhang Lingling , Liu Wei , Guo Shi-Shang , Zhao Xing-Zhong
Published: February 2016

Aiming to synthesize multiferroic materials in microscale, a microfluidic device capable of generating multiferroic Janus microparticles is demonstrated. Through bonding two polydimethylsiloxane (PDMS) layers “face to face,” laminar flow containing an upper layer and a lower layer can be realized. Accordingly, poly(vinylidene fluoride-trifluoroethylene) ferroelectric polymers and Fe3O4 ferromagnetic particles are separately encapsulated in the two layers of a single droplet. Numerical simulation enables the analysis of cross-mixing between the two counterparts and helps to find an optimized location for adding subsequent ultraviolet treatment, which will polymerize the droplets into Janus particles without any side effect. By modulation of the flow rate, the size of the Janus particles can be precisely tuned. Finally, the ferroelectricity and magnetism of the Janus particles are verified by the magnetization and polarization measurements, indicating the multiferroic nature.
High circular polarization in electroluminescence from MoSe2
Authors: Onga Masaru , Zhang Yijin , Suzuki Ryuji , Iwasa Yoshihiro
Published: February 2016

The coupling between the valley degree of freedom and the optical helicity is one of the unique phenomena in transition metal dichalcogenides. The significant valley polarization evaluated from circularly polarized photoluminescence (PL) has been reported in many transition metal dichalcogenides, except in MoSe2. This compound is an anomalous material showing ultra-fast relaxation of the valley polarized states, which causes negligible polarization in the PL. Meanwhile, circularly polarized electroluminescence (EL) has been recently reported in a WSe2 light-emitting transistor, providing another method for using the valley degree of freedom. Here, we report the EL properties of MoSe2, demonstrating electrical switching of the optical helicity. Importantly, we observed high circular polarization reaching 66%. The results imply that the dominant mechanism of circularly polarized EL is robust against intervalley scattering, in marked contrast to the PL.
Reduction of critical current density for out-of-plane mode oscillation in a mag-flip spin torque oscillator using highly spin-polarized Co2Fe(Ga0.5Ge0.5) spin injection layer
Authors: Bosu S. , Sepehri-Amin H. , Sakuraba Y. , Hayashi M. , Abert C. , Suess D. , Schrefl T. , Hono K.
Published: February 2016

We study spin torque oscillators comprised of a perpendicular spin injection layer (SIL) and a planar field generating layer to reveal the influence of the spin polarization of SIL material on the critical current density, JC, to induce microwave oscillation. Two systems with different SIL are compared: one with a highly spin-polarized Heusler alloy, Co2Fe(Ga0.5Ge0.5) (CFGG), and the other a prototypical Fe2Co alloy. Cross sectional scanning transmission electron microscopy observations show the B2-ordered structure in a 3-nm-thick CFGG SIL, a prerequisite for obtaining half-metallic transport properties. Current induced microwave oscillations are found at frequencies of ∼15 GHz for both systems. However, the current needed to cause the oscillations is ∼50% smaller for films with the CFGG SIL compared to those of the Fe2Co SIL. These results are in accordance with micromagnetic simulations that include spin accumulation at the SIL.
Dynamical study of bubble expansion following laser ablation in liquids
Authors: Lam Julien , Lombard Julien , Dujardin Christophe , Ledoux Gilles , Merabia Samy , Amans David
Published: February 2016

This work examines the initial growth and collapse stages of bubbles induced by laser ablation in liquids. First, the bubble shape and size are tracked using an ultrafast camera in a shadowgraph imaging setup. The use of an ultrafast camera ensures a high control of the reproducibility, because a thorough measurement of each bubble lifetime is performed. Next, an analytical cavitation-based model is developed to assess the thermodynamic bubble properties. This study demonstrates that the bubble evolution is adiabatic and driven by inertial forces. Surprisingly, it is found that the bubbles consist of significantly more solvent molecules than ablated matter. These results are valuable to the field of nanoparticle synthesis as they provide insight into the mechanics of laser ablation in liquids.
Wettability transparency and the quasiuniversal relationship between hydrodynamic slip and contact angle
Authors: Ramos-Alvarado Bladimir , Kumar Satish , Peterson G. P.
Published: February 2016

The universality of the scaling laws that correlate the hydrodynamic slip length and static contact angle was investigated by introducing the concept of the wettability transparency of graphene-coated surfaces. Equilibrium molecular dynamics simulations of droplet wettability for Si(111), Si(100), and graphene-coated silicon surfaces were performed to determine the conditions required to obtain similar contact angles between bare and graphene-coated surfaces (wettability transparency). The hydrodynamic slip length was determined by means of equilibrium calculations for silicon and graphene-coated silicon nanochannels. The results indicate that the slip-wettability scaling laws can be used to describe the slip behavior of the bare silicon nanochannels in general terms; however, clear departures from a general universal description were observed for hydrophobic conditions. In addition, a significant difference in the hydrodynamic slippage was observed under wettability transparency conditions. Alternatively, the hydrodynamic boundary condition for silicon and graphene-coated silicon nanochannels was more accurately predicted by observing the density depletion length, posing this parameter as a better alternative than the contact angle to correlate with the slip length.
α,ω-dihexyl-sexithiophene thin films for solution-gated organic field-effect transistors
Authors: Schamoni Hannah , Noever Simon , Nickel Bert , Stutzmann Martin , Garrido Jose A.
Published: February 2016

While organic semiconductors are being widely investigated for chemical and biochemical sensing applications, major drawbacks such as the poor device stability and low charge carrier mobility in aqueous electrolytes have not yet been solved to complete satisfaction. In this work, solution-gated organic field-effect transistors (SGOFETs) based on the molecule α,ω-dihexyl-sexithiophene (DH6T) are presented as promising platforms for in-electrolyte sensing. Thin films of DH6T were investigated with regard to the influence of the substrate temperature during deposition on the grain size and structural order. The performance of SGOFETs can be improved by choosing suitable growth parameters that lead to a two-dimensional film morphology and a high degree of structural order. Furthermore, the capability of the SGOFETs to detect changes in the pH or ionic strength of the gate electrolyte is demonstrated and simulated. Finally, excellent transistor stability is confirmed by continuously operating the device over a period of several days, which is a consequence of the low threshold voltage of DH6T-based SGOFETs. Altogether, our results demonstrate the feasibility of high performance and highly stable organic semiconductor devices for chemical or biochemical applications.
Neutral-depletion-induced axially asymmetric density in a helicon source and imparted thrust
Authors: Takahashi Kazunori , Takao Yoshinori , Ando Akira
Published: February 2016

The high plasma density downstream of the source is observed to be sustained only for a few hundreds of microsecond at the initial phase of the discharge, when pulsing the radiofrequency power of a helicon plasma thruster. Measured relative density of argon neutrals inside the source implies that the neutrals are significantly depleted there. A position giving a maximum plasma density temporally moves to the upstream side of the source due to the neutral depletion and then the exhausted plasma density significantly decreases. The direct thrust measurement demonstrates that the higher thrust-to-power ratio is obtained by using only the initial phase of the high density plasma, compared with the steady-state operation.
Continuous wave lasing from individual GaAs-AlGaAs core-shell nanowires
Authors: Mayer B. , Janker L. , Rudolph D. , Loitsch B. , Kostenbader T. , Abstreiter G. , Koblmüller G. , Finley J. J.
Published: February 2016

We demonstrate single-mode continuous wave (cw) lasing from individual GaAs-AlGaAs core-shell nanowires (NWs) subject to optical excitation. By comparing the s-shaped input-output characteristics of cw-excited NW lasers with those obtained under pulsed excitation at 4 K, we observe a ∼4× lower equivalent pump power for cw-excitation and a lower minimum lasing linewidth of ∼200 μeV, indicative of the steady-state excitation conditions that result in improved temporal coherence of the emission. Analysis of the NW cavity length dependence of the mode characteristics reveals a clear inverse scaling behavior, with the spacing of Fabry–Perot modes corresponding to a group refractive index of ∼8. Remarkably, when subject to cw excitation heating of the NW-lasers is found to be negligible, as verified by a constant lasing linewidth as well as the absence of red-shifted lasing peak emission at high excitation levels.
Commensurate and incommensurate spin-density waves in heavy electron systems
Authors: Schlottmann P.
Published: February 2016

The nesting of the Fermi surfaces of an electron and a hole pocket separated by a nesting vector Q and the interaction between electrons gives rise to itinerant antiferromagnetism. The order can gradually be suppressed by mismatching the nesting and a quantum critical point (QCP) is obtained as the Néel temperature tends to zero. The transfer of pairs of electrons between the pockets can lead to a superconducting dome above the QCP (if Q is commensurate with the lattice, i.e. equal to G/2). If the vector Q is not commensurate with the lattice there are eight possible phases: commensurate and incommensurate spin and charge density waves and four superconductivity phases, two of them with modulated order parameter of the FFLO type. The renormalization group equations are studied and numerically integrated. A re-entrant SDW phase (either commensurate or incommensurate) is obtained as a function of the mismatch of the Fermi surfaces and the magnitude of |Q − G/2|.
Anomalous Hall effects in pseudo-single-crystal γ′-Fe4N thin films
Authors: Kabara Kazuki , Tsunoda Masakiyo , Kokado Satoshi
Published: February 2016

The anomalous Hall effects (AHE) were investigated at various temperatures for the pseudo-single-crystal Fe4N films, deposited on MgO substrates with changing the degree of order (S) of the nitrogen site. Both the anomalous Hall resistivity and the longitudinal resistivity simply decrease with lowering temperature for all the specimens. The AHE of the Fe4N films is presumed to arise from an intrinsic mechanism because of the relationship between the anomalous Hall resistivity and longitudinal resistivity. The anomalous Hall conductivity, σAH, exhibits a specific behavior at low temperature. In the case of the film with S = 0.93, the σAH drastically drops below 50 K, while it simply increases with lowering temperature in the range of 50–300 K. This low-temperature anomaly decays with decreasing S of the film and nearly vanishes in the films with low S. The threshold temperature and the dependence on S of the low-temperature anomaly of the σAH well correspond to those of the anisotropic magnetoresistance effects in the Fe4N films, reported in the literatures. From these results, it is suggested that the low-temperature anomaly of the σAH originates from the crystal field effect which reflects the structural transformation from a cubic to a tetragonal symmetry below 50 K and provides a modulation of the orbital angular momentum of the 3d orbitals at the Fermi level.
Investigation of insulator-metal transition in Ti4O7 using terahertz probe pulse
Authors: Kamioka Hayato , Nishitani Junichi , Tsukada Hiroyuki , Yamaguchi Ryotaro , Suemoto Tohru
Published: February 2016

The ultrafast photo-induced insulator-metal transition in a Ti4O7 single crystal is investigated with different excitation densities using an optical-pump terahertz (THz)-probe technique. The oxide shows a two-step phase transition at 130 K from a low temperature (LT) phase to an intermediate phase and to a high temperature metallic phase at 150 K. The photo-irradiation in the LT phase induces an ultrafast decrease in the transmittance of the THz probe within 3.6 ps, corresponding to the generation of a metallic domain. This is followed by an additional slow decrease when the excitation is above the threshold level. The nonlinear dependence of the amplitude and lifetime on the excitation density indicates that the metallic domains grow spontaneously and are stabilized depending on their resultant amount.
Comparing national images in translations of popular fiction
Authors: Zlatnar Moe Marija , Žigon Tanja
Published: February 2016

This paper concentrates on the way national – and sometimes racial – images are translated in works of popular fiction. Popular fiction is a distinctive literary field, with distinctive norms and conventions, also as regards translation. We explore how these specific translation conventions influence the images of cultures, nations, subcultures and races in the Slovene translations of various popular fiction genres, with a focus on romance, which is usually set in a domestic environment; crime novels, with a more international setting; and fantasy, which often takes place in another universe.
Does bilingual language control decline in older age?
Authors: Ivanova Iva , Murillo Mayra , Montoya Rosa I. , Gollan Tamar H.
Published: February 2016

We investigated age-related decline of bilingual language control. Thirteen older and 13 younger bilinguals performed a verbal fluency task (completing the same letter and semantic categories in each language and switching languages after every category), and a non-linguistic flanker task. In letter fluency, bilinguals produced fewer correct responses after switching languages, suggesting inhibition of the previously-used language. However, this testing-order effect did not differ between groups and older bilinguals produced few wrong-language intrusions, implying intact ability to apply inhibition in older age. In contrast, age-related deficits in the flanker task were robust, implying dissociations between language control and domain-general executive control. In semantic fluency, there were no testing-order effects but older bilinguals produced more intrusions than younger bilinguals, and more intrusions than in letter fluency. Thus, bilinguals may flexibly modulate the degree of inhibition when they can benefit from semantic priming between languages, but less efficiently so in older age.
In situ monitoring hydrogen isotope retention in ITER first wall
Authors: Mukhin E.E. , Andrew P. , Anthoine A.D. , Bazhenov A.N. , Barnsley R. , Bukreev I.M. , Bukhovets V.L. , Chernakov A.P. , Gorodetsky A.E. , Kochergin M.M. , Koval A.N. , Kukushkin A.B. , Kukushkin A.S. , Kurskiev G.S. , Levashova M.G. , Litvinov A.E. , Litunovsky V.N. , Markin A.V. , Mazul I.V. , Masyukevich S.V. , Miroshnikov I.V. , Nemov A.S. , Novokhatsky A.N. , Razdobarin A.G. , Sherstnev E.V. , Samsonov D.S. , Semenov V.V. , Smirnov A.S. , De Temmerman G. , Tolstyakov S.Yu. , Zalavutdinov R.Kh. , Walsh M.J.
Published: February 2016

Tritium retention inside the vacuum vessel is a potentially serious constraint in the operation of large-scale fusion machines like ITER. An in situ diagnostics for first wall H/D/T retention by laser induced desorption spectroscopy (LIDS) is proposed for use between plasma discharges. The technique is based on local baking of the first wall by laser irradiation and subsequent analysis of the in-vessel gas by optical emission spectroscopy of plasma radiation. The local heating implementation, kinetics of H/D/T thermal extraction and the accuracy of optical emission spectroscopy measurements are analysed. To resolve the H/D/T lines spectroscopically, their thermal broadening should be minimized to prevent overlapping of the line shapes. A comparative performance analysis of several types of plasma sources with relatively cold ions is made including the following types of discharges: Penning, RF multipactor, laser torch and ECR. All these radiation sources require rather low power and could be used for remote in situ measurements of relative densities of the thermally extracted hydrogen isotopes.
Core-localized Alfvénic modes driven by energetic ions in HL-2A NBI plasmas with weak magnetic shears
Authors: Chen W. , Yu L.M. , Ding X.T. , Xie H.S. , Shi Z.B. , Ji X.Q. , Yu D.L. , Zhang Y.P. , Shi P.W. , Li Y.G. , Feng B.B. , Jiang M. , Zhong W.L. , Cao J.Y. , Song X.M. , Xu M. , Xu Y.H. , Yan L.W. , Liu Yi , Yang Q.W. , Duan X.R.
Published: February 2016

Recent experimental results that are associated with the core-localized (i.e. normalized radius

) Alfvénic modes in HL-2A neutral beam injection (NBI) plasmas with weak magnetic shears are reported. In the different plasma parameter regions, the energetic ions produced by the NBI drive multiple Alfvénic instabilities, such as the toroidal Alfvén eigenmode (TAE), beta-induced Alfvén eigenmode, reversed shear Alfvén eigenmode (RSAE) and fishbone and energetic particle mode (EPM). Here, we focus on the high-frequency RSAE (HFRSAE) and resonant kinetic ballooning mode (rKBM). A group of downward-sweeping frequency coherent modes (HFRSAEs) with 100  <  f  <  500 kHz and n  =  3–7 are often observed with an increase in the edge safety factor, q

a
. Their measured frequency is more than that of the TAEs, and

. The analysis suggests that these modes localize inside the high-order Alfvén eigenmode (AE) gap of the Alfvénic continuum, and their eigenfrequency and eigenfunction depend on the

and q-profile. When the core plasma density is more than

m−3 and the impurity or supersonic molecular beam enters the bulk plasma, the profiles of the plasma density/pressure peak, and the magnetic shear is weak or negative. In this case, a group of multi-harmonic coherent modes (rKBMs) with 30  <  f  <  150 kHz and n  =  2–9 are observed through multiple diagnostic techniques, and

, where

is the diamagnetic drift frequency of the thermal ion. It is found that the HFRSAEs can transit into the rKBMs when the density profile suddenly peaks. Neutron monitoring outside the vacuum chamber demonstrates that the HFRSAE and rKBM both degrade the confinement of the energetic ions. The rKBM instabilities also affect the bulk plasma performance.
A study of 239Pu production rate in a water cooled natural uranium blanket mock-up of a fusion–fission hybrid reactor
Authors: Feng Song , Liu Rong , Lu Xinxin , Yang Yiwei , Xu Kun , Wang Mei , Zhu Tonghua , Jiang Li , Qin Jianguo , Jiang Jieqiong , Han Zijie , Lai Caifeng , Wen Zhongwei
Published: February 2016

The 239Pu production rate is important data in neutronics design for a natural uranium blanket of a fusion–fission hybrid reactor, and the accuracy and reliability should be validated by integral experiments. The distribution of 239Pu production rates in a subcritical natural uranium blanket mock-up was obtained for the first time with a D-T neutron generator by using an activation technique. Natural uranium foils were placed in different spatial locations of the mock-up, the counts of 277.6 keV γ-rays emitted from 239Np generated by 238U capture reaction were measured by an HPGe γ spectrometer, and the self-absorption of natural uranium foils was corrected. The experiment was analyzed using the Super Monte Carlo neutron transport code SuperMC2.0 with recent nuclear data of 238U from the ENDF/B-VII.0, ENDF/B-VII.1, JENDL-4.0u2, JEFF-3.2 and CENDL-3.1 libraries. Calculation results with the JEFF-3.2 library agree with the experimental ones best, and they agree within the experimental uncertainty in general with the average ratios of calculation results to experimental results (C/E) in the range of 0.93 to 1.01.
The star formation rates of active galactic nuclei host galaxies
Authors: Ellison Sara L. , Teimoorinia Hossen , Rosario David J. , Mendel J. Trevor
Published: February 2016

Using artificial neural network predictions of total infrared luminosities (LIR), we compare the host galaxy star formation rates (SFRs) of ∼21 000 optically selected active galactic nuclei (AGN), 466 low-excitation radio galaxies (LERGs) and 721 mid-IR-selected AGN. SFR offsets (ΔSFR) relative to a sample of star-forming ‘main-sequence’ galaxies (matched in M⋆, z and local environment) are computed for the AGN hosts. Optically selected AGN exhibit a wide range of ΔSFR, with a distribution skewed to low SFRs and a median ΔSFR = −0.06 dex. The LERGs have SFRs that are shifted to even lower values with a median ΔSFR = −0.5 dex. In contrast, mid-IR-selected AGN have, on average, SFRs enhanced by a factor of ∼1.5. We interpret the different distributions of ΔSFR amongst the different AGN classes in the context of the relative contribution of triggering by galaxy mergers. Whereas the LERGs are predominantly fuelled through low accretion rate secular processes which are not accompanied by enhancements in SFR, mergers, which can simultaneously boost SFRs, most frequently lead to powerful, obscured AGN.
Wealth, Health, and Child Development: Evidence from Administrative Data on Swedish Lottery Players *
Authors: Cesarini David , Lindqvist Erik , Östling Robert , Wallace Björn
Published: February 2016

We use administrative data on Swedish lottery players to estimate the causal impact of substantial wealth shocks on players’ own health and their children’s health and developmental outcomes. Our estimation sample is large, virtually free of attrition, and allows us to control for the factors conditional on which the prizes were randomly assigned. In adults, we find no evidence that wealth impacts mortality or health care utilization, with the possible exception of a small reduction in the consumption of mental health drugs. Our estimates allow us to rule out effects on 10-year mortality one sixth as large as the cross-sectional wealth-mortality gradient. In our intergenerational analyses, we find that wealth increases children’s health care utilization in the years following the lottery and may also reduce obesity risk. The effects on most other child outcomes, including drug consumption, scholastic performance, and skills, can usually be bounded to a tight interval around zero. Overall, our findings suggest that in affluent countries with extensive social safety nets, causal effects of wealth are not a major source of the wealth-mortality gradients, nor of the observed relationships between child developmental outcomes and household income.
Value of Gamma‐Glutamyl Transpeptidase for Diagnosis of Biliary Atresia by Correlation With Age
Authors: Chen Xiaoli , Dong Rui , Shen Zhen , Yan Weili , Zheng Shan
Published: February 2016

Objectives:

The aim of the study was to analyze the value of gamma‐glutamyl transpeptidase (GGT) for distinguishing biliary atresia (BA) from non‐BA for patients suspected of having neonatal obstructive jaundice by correlation with age.

Methods:

From January 2003 to March 2014, cholangiography and/or surgical exploration were undertaken in 1469 patients with suspicion of having neonatal obstructive jaundice. A total of 1338 patients were diagnosed with BA intraoperatively. Preoperative medical records were compared between BA and non‐BA patients.

Results:

Preoperative levels of total bilirubin, direct bilirubin, and GGT were significantly higher in the BA group (P < 0.05), whereas the non‐BA group had higher alkaline phosphatase levels (P = 0.0003). The area under the receiver operating characteristic curve of total bilirubin, direct bilirubin, GGT, and alkaline phosphatase was 0.584, 0.614, 0.843, and 0.398, respectively. In all age groups (i: 31–60 days; ii: 61–90 days; iii: 91–120 days; iv: ≥121 days), BA groups had higher GGT levels (in IU/L) (i: 725.3 ± 549.9; ii: 927.0 ± 679.8; iii: 1114.3 ± 823.1; iv: 767.5 ± 666.7). The level of GGT in patients with BA younger than 30 days was 834.2 ± 475.3 IU/L. GGT levels had the highest diagnostic value (0.869) in group ii (61–90 days) and the lowest diagnosis value (0.712) in group iv (≥121 days). At a cutoff of >303 IU/L in group ii (61–90 days), GGT had 82.8% sensitivity and 81.6% specificity for the discrimination of BA.

Conclusions:

GGT levels contribute to the diagnosis of BA before 120 days. Age must be considered if using GGT levels as a diagnostic test for BA.
Mismatch Repair Protein Expression in Fordyce Granules
Authors: Fernandez-Flores Angel , Rodríguez Peralto José L.
Published: February 2016

Fordyce spots are a frequent condition under which sebaceous glands are found in the oral mucosa. There are 2 studies in the literature that have found an association between Fordyce spots and either Muir-Torre syndrome or Lynch syndrome. Despite this, no study on the expression of mismatch repair (MMR) proteins has been performed on biopsies of Fordyce granules. In this study, we intend to study the expression of MMR proteins under Fordyce condition. We investigated 9 cases of Fordyce spots of the oral mucosa from 6 men and 3 women, using immunohistochemistry with antibodies for the MutS protein homolog 6 (MSH6), MutS protein homolog 2 (MSH2), MutL protein homolog 1 (MLH1), and postmeiotic segregation increased 2 (PMS2). All cases showed the preservation of the expression of all markers. Even though a strong association has been demonstrated between Lynch syndrome and Fordyce spots, our study suggests that studying the biopsies of Fordyce condition by immunohistochemistry for MMR proteins might not be necessary.
TGF-β and CTGF are Mitogenic Output Mediators of Wnt/β-Catenin Signaling in Desmoid Fibromatosis
Authors: Varghese Sumi , Braggio Danielle A. , Gillespie Jessica , Toland Amanda E. , Pollock Raphael , Mayerson Joel , Scharschmidt Thomas , Iwenofu Obiajulu H.
Published: February 2016

Desmoid fibromatosis is a locally aggressive clonal fibroblastic proliferation with high recurrence rates and no metastatic potential. Implicated molecular aberrations occur within the Wnt/β-catenin pathway (APC and β-catenin gene mutations). Transforming growth factor-β (TGF-β) and connective tissue growth factor (CTGF) are profibrotic growth factors, downstream from nuclear translocation of β-catenin, that lead to increased fibrogenesis. CTGF (a downstream effector of TGF-β) is a matricellular protein that modulates the activity of growth factors, adhesion molecules, integrins, and extracellular matrix thus playing a central role in tissue remodeling and fibrosis. Recently there has been growing interest in use of extracellular matrix inhibitors for treatment of various fibrogenic diseases. Desmoid fibromatosis samples (n=15) were evaluated for expression of β-catenin, TGF-β, and CTGF using immunohistochemistry on formalin paraffin-embedded material. A control group comprising scar tissue and adjacent normal skin (n=10) were simultaneously immunostained with above mentioned markers. Real-time polymerase chain reaction was performed on frozen specimens of desmoid fibromatosis (n=6) and normal skin (n=2). All 15 desmoid tumors were positive for β-catenin (surrogate marker of Wnt/β-catenin pathway dysregulation) which was negative in control normal skin and scar samples. TGF-β and CTGF were negative in 9 of 10 normal skin controls. TGF-β and CTGF were positive in all cases of scar tissue. All 15 cases of desmoid tumors were positive for TGF-β and CTGF. The real-time polymerase chain reaction showed higher expression levels of TGF-β and CTGF in desmoid fibromatosis compared with normal skin. The high constitutive expression of β-catenin downstream effectors; TGF-β, CTGF has the potential for enabling targeted therapy.
Analysis of References on the Plastic Surgery In-Service Training Exam
Authors: Silvestre Jason , Zhang Alicia , Lin Samuel J.
Published: February 2016

Background:

The Plastic Surgery In-Service Training Exam is a knowledge assessment tool widely used during plastic surgery training in the United States. This study analyzed literature supporting correct answer choices to determine highest yield sources, journal publication lag, and journal impact factors.

Methods:

Digital syllabi of 10 consecutive Plastic Surgery In-Service Training Exam administrations (2006 to 2015) were reviewed. The most-referenced articles, journals, and textbooks were determined. Mean journal impact factor and publication lag were calculated and differences were elucidated by section.

Results:

Two thousand questions and 5386 references were analyzed. From 2006 to 2015, the percentage of journal citations increased, whereas textbook references decreased (p < 0.001). Plastic and Reconstructive Surgery was cited with greatest frequency (38.5 percent), followed by Clinics in Plastic Surgery (5.6 percent), Journal of Hand Surgery (American volume) (5.1 percent), and Annals of Plastic Surgery (3.8 percent). There was a trend toward less publication lag over the study period (p = 0.05), with a mean publication lag of 9.1 ± 9.0 years for all journal articles. Mean journal impact factor was 2.3 ± 4.3 and lowest for the hand and lower extremity section (1.7 ± 2.8; p < 0.001). The highest yield textbooks were elucidated by section.

Conclusion:

Plastic surgery faculty and residents may use these data to facilitate knowledge acquisition during residency.
Evolving Concepts of Keystone Perforator Island Flaps (KPIF): Principles of Perforator Anatomy, Design Modifications, and Extended Clinical Applications
Authors: Mohan Anita T. , Rammos Charalambos K. , Akhavan Arya A. , Martinez Jorys , Wu Peter S. , Moran Steven L. , Sim Franklin H. , Behan Felix , Mardini Samir , Saint-Cyr Michel
Published: February 2016

Background:

Keystone flaps have demonstrated growing clinical applications in reconstructive surgery in the past decade. This article highlights flap modifications and their versatility for clinical applications and management of complex defects.

Methods:

A retrospective chart review was conducted of consecutive patients undergoing keystone flap reconstruction at the authors’ institution from January of 2012 to December of 2014. Patient demographics, indications, and operative and postoperative details were abstracted.

Results:

Forty-two keystone flaps were performed in 36 patients. Indications included malignant melanoma (n = 14), soft-tissue sarcoma (n = 12), benign pathologic conditions (e.g., exposed hardware, enterocutaneous fistula, tissue necrosis) (n = 6), and nonmelanoma skin cancer (n = 4). Twenty-eight percent received neoadjuvant irradiation, and 70 percent of these were for sarcoma. Locoregional adjunct flaps were performed in eight patients. The deep fascia was nearly completely in a circumferential manner in 18 of 36 patients (50 percent), in 92 percent of the sarcoma reconstructions, and located mainly in the lower extremity. Average defect size was 215 cm2 (range, 4 to 1000 cm2). Average defect size was 474 cm2 and 35.8 cm2 after sarcoma and malignant melanoma resection, respectively. Average flap size was 344 cm2 (range, 5 to 1350 cm2). Ninety percent of cases had flap sizes exceeding the traditional 1:1 ratio. There was no flap loss or partial necrosis. Mean time to mobilization was 1.8 days, and mean hospital length of stay was 6.8 days.

Conclusions:

Keystone flaps offer an excellent versatile tool for reconstructive surgeons. Fundamental principles behind the vascular basis of the keystone flap and its modifications permit their greater utility in complex wounds in the settings of large oncologic resections, irradiation, and trauma.

CLINICAL QUESTION/LEVEL OF EVIDENCE:

Therapeutic, IV.
Human Factors and Quality Improvement in the Emergency Department: Reducing Potential Errors in Blood Collection
Authors: Bashkin Osnat , Caspi Sigalit , Swissa Assaf , Amedi Amitai , Zornano Shai , Stalnikowicz Ruth
Published: February 2016

Objectives

Adverse events in blood collection procedures such as mismatched or unlabeled samples may have critical implications on patient safety (such as wrong diagnosis and treatments). The current study examined blood collection procedures in an emergency department before and after the application of a human factors approach for improving performance quality and preventing adverse events.

Methods

In the emergency department of a community care hospital, 190 blood collection events were observed in 2 phases: preintervention and postintervention. Two quality measures were tested as follows: quality measure 1, performing all 7 stages in the procedure of blood collection according to protocol, and quality measure 2, performing the stages of the procedure in the correct sequence according to the protocol. In addition, medical staff anonymously answered questionnaires about their procedure for collecting blood.

Results

Analyses of data collected before the intervention revealed only 2 events in which all 7 stages in the protocol of the procedure were performed and only 1 event in which the 7 stages of the procedure were performed in the correct sequence. In 91% of the events, the patient was not fully identified. Based on these findings, we developed an intervention using a human factors approach to improve the quality of performance. Analyses of data collected after the intervention revealed significant differences (t188 = −14.9, ρ < 0.01) in quality measure 1 before (mean [SD], 4.8 [0.6]) and after (mean [SD], 6.4 [0.8]) the intervention was initiated, which implies improvement on efficiency subsequent to the implementation of the intervention. Improvement also appeared in quality measure 2.

Conclusions

This study illustrates the nature of potential errors in blood collection performance, offering a proactive approach to improve the rate of proper performance.