bluuebunny/crossref_metadata_2025 huggingface dataset:
An Evidence-Based Systematic Review on the Diagnostic Accuracy of Hearing Screening Instruments for Preschool- and School-Age Children
Authors: Prieve Beth A. , Schooling Tracy , Venediktov Rebecca , Franceschini Nicole
Published: March 2015

Purpose

The purpose of this article is to conduct an evidence-based systematic review on the accuracy of pure-tone or otoacoustic emission (OAE) screening for identifying hearing loss in preschool- and school-age children.

Method

A systematic search of the literature published between 1975 and 2013 was conducted. Articles meeting the selection criteria were critically appraised for quality. Selection criteria required that behavioral thresholds be measured in children failing the screen and in at least a subset of children passing the screen. Sensitivity and specificity were used to calculate positive and negative likelihood ratios that could be compared between instruments.

Results

Eighteen studies were included in the final analysis. There was considerable variability among studies on stimulus levels, response criteria, and definition of hearing loss. Approximately half of positive and negative likelihood ratio pairs for OAEs (52%) and pure-tone screening (45%) were considered suggestive or informative for identifying hearing loss.

Conclusions

Both pure-tone and OAE screening can identify hearing loss in preschool- and school-age children. Studies that compared both tools in the same population concluded that pure-tone screening had higher sensitivity than OAE screening and thus was considered the preferred tool. Future research should incorporate standard stimulus levels, response criteria, and definitions of hearing loss.
Exploration of kc‐cycle transient fault‐secured datapath and loop unrolling factor for control data flow graphs during high‐level synthesis
Authors: Sengupta A.
Published: March 2015

Simultaneous design space exploration (DSE) of kc‐cycle transient fault‐secured datapath and loop unrolling factor (UF) for control data flow graphs (CDFGs) during high‐level synthesis is an unsolved problem in the literature. The aforementioned problems are solved with the following specific contributions: (i) a novel DSE methodology that explores an optimal combination of transient fault‐secured datapath configuration and loop UF using particle swarm optimisation for CDFG, and (ii) the novel kc‐cycle fault secured algorithm. Finally, the proposed approach when tested on standard benchmarks yielded an optimal solution which minimises the fitness function and satisfies user constraints, as well as achieving significantly reduced cost of the final solution when compared with a recent fault‐secured approach.
Auto‐encoder‐based shared mid‐level visual dictionary learning for scene classification using very high resolution remote sensing images
Authors: Cheng Gong , Zhou Peicheng , Han Junwei , Guo Lei , Han Jungong
Published: March 2015

Effective representation and classification of scenes using very high resolution (VHR) remote sensing images cover a wide range of applications. Although robust low‐level image features have been proven to be effective for scene classification, they are not semantically meaningful and thus have difficulty to deal with challenging visual recognition tasks. In this study, the authors propose a new and effective auto‐encoder‐based method to learn a shared mid‐level visual dictionary. This dictionary serves as a shared and universal basis to discover mid‐level visual elements. On the one hand, the mid‐level visual dictionary learnt using machine learning technique is more discriminative and contains rich semantic information, compared with the traditional low‐level visual words. On the other hand, the mid‐level visual dictionary is more robust to occlusions and image clutters. In the authors' scene‐classification scheme, they use discriminative mid‐level visual elements, rather than individual pixels or low‐level image features, to represent images. This new image representation is able to capture much of the high‐level meaning and contents of the image, facilitating challenging remote sensing image scene‐classification tasks. Comprehensive evaluations on a challenging VHR remote sensing images data set and comparisons with state‐of‐the‐art approaches demonstrate the effectiveness and superiority of their study.
Improving the gas sensing response of polyaniline via a porous carbon nanotube‐based template
Authors: Li Wei , Guan Panpan , Wei Aili , Zhang Huaiping , Zhai Hui
Published: March 2015

Tin metal was coated onto single‐walled carbon nanotubes by sputtering and then thermally oxidised to form a stable tin oxide/single‐walled carbon nanotubes porous template on glass substrate. Polyaniline (PANI) was coated onto this template through oxidative polymerisation. The nanocomposite was characterised by scanning electron microscopy, infrared spectra and Raman spectra. The sensor response of the nanocomposite to an aromatic organic compound (AOC) was investigated in the comparison with pure PANI. The results show that, upon exposure to the AOC, the conductivity of the sensor increases and the response of the nanocomposite is much higher than that of pure PANI.
Reference Correlation of the Viscosity of para-Xylene from the Triple Point to 673 K and up to 110 MPa
Authors: Balogun B. , Riesco N. , Vesovic V.
Published: March 2015

A new correlation for the viscosity of para-xylene (p-xylene) is presented. The correlation is based upon a body of experimental data that has been critically assessed for internal consistency and for agreement with theory. It is applicable in the temperature range from the triple point to 673 K at pressures up to 110 MPa. The overall uncertainty of the proposed correlation, estimated as the combined expanded uncertainty with a coverage factor of 2, varies from 0.5% for the viscosity of the dilute gas to 5% for the highest temperatures and pressures of interest. Tables of the viscosity generated by the relevant equations, at selected temperatures and pressures and along the saturation line, are provided.
Start-up vortex flow past an accelerated flat plate
Authors: Xu Ling , Nitsche Monika
Published: March 2015

Viscous flow past a finite flat plate accelerating in the direction normal to itself is studied numerically. The plate moves with nondimensional speed tp, where p = 0, 1/2, 1, 2. The work focuses on resolving the flow at early to moderately large times and determining the dependence on the acceleration parameter p. Three stages in the vortex evolution are identified and quantified. The first stage, referred to as the Rayleigh stage [Luchini and Tognaccini, “The start-up vortex issuing from a semi-infinite flat plate,” J. Fluid Mech. 455, 175–193 (2002)], consists of a vortical boundary layer of roughly uniform thickness surrounding the plate and its tip, without any separating streamlines. This stage is present only for p > 0, for a time-interval that scales like p3, as p → 0. The second stage is one of self-similar growth. The vortex trajectory and circulation satisfy inviscid scaling laws, the boundary layer thickness satisfies viscous laws. The self-similar trajectory starts immediately after the Rayleigh stage ends and lasts until the plate has moved a distance d = 0.5 to 1 times its length. Finally, in the third stage, the image vorticity due to the finite plate length becomes relevant and the flow departs from self-similar growth. The onset of an instability in the outer spiral vortex turns is also observed, however, at least for the zero-thickness plate considered here, it is shown to be easily triggered numerically by underresolution. The present numerical results are compared with experimental results of Pullin and Perry [“Some flow visualization experiments on the starting vortex,” J. Fluid Mech. 97, 239–255 (1980)], and numerical results of Koumoutsakos and Shiels [“Simulations of the viscous flow normal to an impulsively started and uniformly accelerated flat plate,” J. Fluid Mech. 328, 177–227 (1996)].
A design study for a compact two stage in-flight separator with a high mass resolution and large acceptance
Authors: Hwang Ji-Gwang , Kim Eun-San , Hatanaka Kichiji
Published: March 2015

The rare isotope beam separator with a large angular acceptance and energy acceptance is essential for examining the characteristics of unstable nuclei and exotic nuclear reactions. Careful design, however, is required to compensate for the effects of high order aberrations induced by large aperture magnets, which are used to collect rare isotopes obtained from a high energy primary heavy-ion beam hitting a target. In order to minimize the effect of the high order aberration, the optics was based on the mirror symmetry optics, which provides smaller high order aberrations, for the separation of 132Sn produced by a fission reaction between the primary beam of 238U and a relatively thick Pb target. The designed optics provides energy acceptance (full), horizontal angular acceptance, and vertical acceptance of approximately 8%, 60 mrad, and 130 mrad, respectively.
Paramagnetic to antiferromagnetic transition in epitaxial tetragonal CuMnAs (invited)
Authors: Hills V. , Wadley P. , Campion R. P. , Novak V. , Beardsley R. , Edmonds K. W. , Gallagher B. L. , Ouladdiaf B. , Jungwirth T.
Published: March 2015

In this paper, we use neutron scattering and electrical transport to investigate the paramagnetic to antiferromagnetic phase transition in tetragonal CuMnAs films on GaP(001). X-ray diffraction and cross-sectional transmission electron microscopy measurements show that the films are chemically ordered with high structural quality. The temperature dependence of the structurally forbidden (100) neutron scattering peak is used to determine the Néel temperature, TN. We then demonstrate the presence of a clear peak in the temperature derivative of the resistivity around TN. The effect of disorder-induced broadening on the shape of the peak is discussed.
Computational modelling of the interaction of shock waves with multiple gas-filled bubbles in a liquid
Authors: Betney M. R. , Tully B. , Hawker N. A. , Ventikos Y.
Published: March 2015

This study presents a computational investigation of the interactions of a single shock wave with multiple gas-filled bubbles in a liquid medium. This work illustrates how multiple bubbles may be used in shock-bubble interactions to intensify the process on a local level. A high resolution front-tracking approach is used, which enables explicit tracking of the gas-liquid interface. The collapse of two identical bubbles, one placed behind the other is investigated in detail, demonstrating that peak pressures in a two bubble arrangement can exceed those seen in single bubble collapse. Additionally, a parametric investigation into the effect of bubble separation is presented. It is found that the separation distance has a significant effect on both the shape and velocity of the main transverse jet of the second bubble. Extending this analysis to effects of relative bubble size, we show that if the first bubble is sufficiently small relative to the second, it may become entirely entrained in the second bubble main transverse jet. In contrast, if the first bubble is substantially larger than the second, it may offer it significant protection from the incident shock. This protection is utilised in the study of a triangular array of three bubbles, with the central bubble being significantly smaller than the outer bubbles. It is demonstrated that, through shielding of bubbles until later in the collapse process, pressures over five times higher than the maximum pressure observed in the single bubble case may be achieved. This corresponds to a peak pressure that is approximately 40 times more intense than the incident shock wave. This work has applications in a number of different fields, including cavitation erosion, explosives, targeted drug delivery/intensification, and shock wave lithotripsy.
Proof-of-concept framework to separate recombination processes in thin silicon wafers using transient free-carrier absorption spectroscopy
Authors: Siah S. C. , Winkler M. T. , Powell D. M. , Johnston S. W. , Kanevce A. , Levi D. H. , Buonassisi T.
Published: March 2015

We present a proof-of-concept framework to independently determine the bulk Shockley-Read-Hall (SRH) lifetime and surface recombination velocity in silicon wafers self-consistently. We measure the transient decay of free-carrier absorption (FCA) using two different excitation wavelengths (1050 and 750 nm) for p-type crystalline Si (c-Si) wafers over a wide injection range and fit the FCA transients for the two excitation wavelengths in a coupled manner. In this way, we can estimate the surface recombination lifetime accurately. However, we find that the capability to uniquely measure extrinsic bulk-SRH recombination is challenging in the presence of other recombination processes and can be broadly categorized into five different regimes depending on the relative strengths of each recombination pathway.
Shear driven droplet shedding and coalescence on a superhydrophobic surface
Authors: Moghtadernejad S. , Tembely M. , Jadidi M. , Esmail N. , Dolatabadi A.
Published: March 2015

The interest on shedding and coalescence of sessile droplets arises from the importance of these phenomena in various scientific problems and industrial applications such as ice formation on wind turbine blades, power lines, nacelles, and aircraft wings. It is shown recently that one of the ways to reduce the probability of ice accretion on industrial components is using superhydrophobic coatings due to their low adhesion to water droplets. In this study, a combined experimental and numerical approach is used to investigate droplet shedding and coalescence phenomena under the influence of air shear flow on a superhydrophobic surface. Droplets with a size of 2 mm are subjected to various air speeds ranging from 5 to 90 m/s. A numerical simulation based on the Volume of Fluid method coupled with the Large Eddy Simulation turbulent model is carried out in conjunction with the validating experiments to shed more light on the coalescence of droplets and detachment phenomena through a detailed analysis of the aerodynamics forces and velocity vectors on the droplet and the streamlines around it. The results indicate a contrast in the mechanism of two-droplet coalescence and subsequent detachment with those related to the case of a single droplet shedding. At lower speeds, the two droplets coalesce by attracting each other with successive rebounds of the merged droplet on the substrate, while at higher speeds, the detachment occurs almost instantly after coalescence, with a detachment time decreasing exponentially with the air speed. It is shown that coalescence phenomenon assists droplet detachment from the superhydrophobic substrate at lower air speeds.
Disorder persistent transparency within the bandgap of a periodic array of acoustic Helmholtz resonators
Authors: Richoux O. , Maurel A. , Pagneux V.
Published: March 2015

In this paper, the influence of disorder on 1D periodic lattice of resonant scatterers is inspected. These latter have multiple resonance frequencies which produce band gaps in the transmission spectrum. One peculiarity of the presented system is that it is chosen with a nearly perfect overlap between the Bragg and the second hybridization band gaps. In the case of a perfectly ordered lattice, and around this overlap, this produces a narrow transparency band within a large second bandgap. As expected, the effect of the disorder is generally to increase the width of the band gaps. Nevertheless, the transparency band appears to be robust with respect to an increase in the disorder. In this paper, we study this effect by means of experimental investigations and numerical simulations.
Energy level of the Si-related DX-center in (AlyGa1−y)1−xInxAs
Authors: Heckelmann Stefan , Lackner David , Bett Andreas W.
Published: March 2015

For the quaternary material (AlyGa1−y)1−xInxAs, the energy level of the silicon-related deep electron trap known as the DX-center is calculated. In addition, the composition range y(x) is derived, for which the silicon-related DX-center level is below the conduction band minimum and thus electronically active. Eventually, the result of the calculation is compared with available measurement data, revealing good agreement regarding the composition when the DX-center energy level crosses the conduction band minimum.
Wicking and flooding of liquids on vertical porous sheets
Authors: Kim Seong Jin , Choi Jin Woo , Moon Myoung-Woon , Lee Kwang-Ryeol , Chang Young Soo , Lee Dae-Young , Kim Ho-Young
Published: March 2015

When one brings a wet paintbrush into contact with a vertical watercolor paper, the paint may wick into the porous sheet completely or run down to ruin the art. We study a simple model of this spreading dynamics of liquids on hydrophilic porous sheets under the effects of gravity, using a capillary as a liquid source and thin fabrics of non-woven polyethylene terephthalate. Upon finding the maximum flow rate, Qw, that can be absorbed into the fabric, we show that the model can be used to obtain an estimate of the in-plane permeability of fabrics in a simpler manner than the conventional schemes. The shape of a wetting area that grows when the flow rate exceeds Qw to lead to rivulet formation is also theoretically given. The nose shape of the wetting front is shown to be time-invariant, while its profile depends on the properties of the liquid and the fabric. This study can be applied to understand and improve the liquid absorption behavior of hygiene items, heating, ventilation, and air-conditioning equipments, and fuel cell membranes in addition to elucidating the mundane painting activity.
Polarization-induced transport in ferroelectric organic field-effect transistors
Authors: Laudari A. , Guha S.
Published: March 2015

Ferroelectric dielectrics, permitting access to nearly an order of magnitude range of dielectric constants with temperature as the tuning parameter, offer a great platform to monitor the changes in interfacial transport in organic field-effect transistors (OFETs) as the polarization strength is tuned. Temperature-dependent transport studies have been carried out from pentacene-based OFETs using the ferroelectric copolymer poly(vinylidene fluoride-co-trifluoroethylene) (PVDF-TrFE) as a gate insulating layer. The thickness of the gate dielectric was varied from 20 nm to 500 nm. By fits to an Arrhenius-type dependence of the charge carrier mobility as a function of temperature, the activation energy in the ferroelectric phase is found to increase as the thickness of the PVDF-TrFE layer decreases. The weak temperature-dependence of the charge carrier mobility in the ferroelectric phase of PVDF-TrFE may be attributed to a polarization fluctuation driven transport, which results from a coupling of the charge carriers to the surface phonons of the dielectric. By comparing single layer PVDF-TrFE pentacene OFETs with stacked PVDF-TrFE/inorganic dielectric OFETs, the contribution from Fröhlich polarons is extracted. The temperature-dependent mobility of the polarons increases with the thickness of the PVDF-TrFE layer. Using a strongly coupled polaron model, the hopping lengths were determined to vary between 2 Å and 5 Å.
Inapplicability of Martin transformation to elastic constants of zinc-blende and wurtzite group-III nitride alloys
Authors: Łepkowski S. P.
Published: March 2015

The applicability of the Martin transformation [R. M. Martin, Phys. Rev. B 6, 4546 (1972)] to the elastic constants of wurtzite and zinc-blende group-III nitride alloys is examined using density functional theory calculations. The composition dependencies of the elastic constants in InGaN, AlGaN, and InAlN are determined by means of ab-initio calculations and compared with the results obtained from the Martin's method. A detailed analysis reveals that the Martin transformation can approximate reasonably well the dependence of the elastic constants on composition in wurtzite InGaN alloys, except for the case of C33 where it predicts too small bowing. However, it fails to reproduce correctly the composition dependencies of C13 and C33 in wurtzite InAlN and C13, C33, and C44 in wurtzite AlGaN. In order to identify the origin of the failure of the Martin transformation, the effective elastic constants of strained wurtzite alloys with the ideal value of the lattice axial ratio c/a have been investigated. It is shown that these effective elastic constants are significantly closer to the elastic constants predicted by the Martin's method which indicates that the breakdown of the Martin transformation in group III nitride alloys is partially caused by the deviation of the c/a axial ratio from the ideal value.
Physical mechanisms of SiNx layer structuring with ultrafast lasers by direct and confined laser ablation
Authors: Rapp S. , Heinrich G. , Wollgarten M. , Huber H. P. , Schmidt M.
Published: March 2015

In the production process of silicon microelectronic devices and high efficiency silicon solar cells, local contact openings in thin dielectric layers are required. Instead of photolithography, these openings can be selectively structured with ultra-short laser pulses by confined laser ablation in a fast and efficient lift off production step. Thereby, the ultrafast laser pulse is transmitted by the dielectric layer and absorbed at the substrate surface leading to a selective layer removal in the nanosecond time domain. Thermal damage in the substrate due to absorption is an unwanted side effect. The aim of this work is to obtain a deeper understanding of the physical laser-material interaction with the goal of finding a damage-free ablation mechanism. For this, thin silicon nitride (SiNx) layers on planar silicon (Si) wafers are processed with infrared fs-laser pulses. Two ablation types can be distinguished: The known confined ablation at fluences below 300 mJ/cm2 and a combined partial confined and partial direct ablation at higher fluences. The partial direct ablation process is caused by nonlinear absorption in the SiNx layer in the center of the applied Gaussian shaped laser pulses. Pump-probe investigations of the central area show ultra-fast reflectivity changes typical for direct laser ablation. Transmission electron microscopy results demonstrate that the Si surface under the remaining SiNx island is not damaged by the laser ablation process. At optimized process parameters, the method of direct laser ablation could be a good candidate for damage-free selective structuring of dielectric layers on absorbing substrates.
Highly conductive single naphthalene and anthracene molecular junction with well-defined conductance
Authors: Liu Chenyang , Kaneko Satoshi , Komoto Yuki , Fujii Shintaro , Kiguchi Manabu
Published: March 2015

We performed electronic investigation on single acene molecular junctions bridging Au-electrodes in ultra-high vacuum conditions using mechanically controllable break junction technique. While the molecular junctions displayed various conductance values at 100 K, they exhibited well-defined high conductance values (∼0.3 G0) at 300 K, which is close to that of metal atomic contact. Direct π-binding of the molecules to the Au-electrodes leads to the high conductivities at the metal-molecule interface. At the elevated temperature, single molecular junctions trapped in local metastable structures can be fallen into energetically preferential more stable state and thus we fabricated structurally well-defined molecular junctions.
Permittivity evaluation of multilayered hyperbolic metamaterials: Ellipsometry vs. reflectometry
Authors: Tumkur T. , Barnakov Y. , Kee S. T. , Noginov M. A. , Liberman V.
Published: March 2015

Metal-dielectric nanolaminates represent a class of hyperbolic metamaterials with uniaxial permittivity tensor. In this study, we critically compare permittivity extraction of nanolaminate samples using two techniques: polarized reflectometry vs. spectroscopic anisotropic ellipsometry. Both Au/MgF2 and Ag/MgF2 metal-dielectric stacks are examined. We demonstrate the applicability of the treatment of the multilayered material as a uniaxial medium and compare the derived optical parameters to those expected from the effective medium approximation. We also experimentally compare the effect of varying the material outer layer on the homogenization of the composite. Additionally, we introduce a simple empirical method of extracting the epsilon-near-zero point of the nanolaminates from normal incidence reflectance. The results of this study are useful in accurate determination of the hyperbolic material permittivity and in the ability to tune its optical properties.
Transition from semiconducting to metallic-like conducting and weak antilocalization effect in single crystals of LuPtSb
Authors: Hou Zhipeng , Wang Yue , Xu Guizhou , Zhang Xiaoming , Liu Enke , Wang Wenquan , Liu Zhongyuan , Xi Xuekui , Wang Wenhong , Wu Guangheng
Published: March 2015

High quality half-Heusler single crystals of LuPtSb have been synthesized by a Pb flux method. The temperature dependent resistivity and Hall effects indicate that the LuPtSb crystal is a p-type gapless semiconductor showing a transition from semiconducting to metallic conducting at 150 K. Moreover, a weakly temperature-dependent positive magnetoresistance (MR) as large as 109% and high carrier mobility up to 2950 cm2/V s are experimentally observed at temperatures below 150 K. The low-field MR data show evidence for weak antilocalization (WAL) effect at temperatures even up to 150 K. Analysis of the temperature and angle dependent magnetoconductance manifests that the WAL effect originates from the bulk contribution owing to the strong spin-orbital coupling.
Nanosized perpendicular organic spin-valves
Authors: Göckeritz Robert , Homonnay Nico , Müller Alexander , Richter Tim , Fuhrmann Bodo , Schmidt Georg
Published: March 2015

A fabrication process for perpendicular organic spin-valve devices based on the organic semiconductor Alq3 has been developed which offers the possibility to achieve active device areas of less than 500 × 500 nm2 and is flexible in terms of material choice for the active layers. Characterization of the resulting devices shows a large magnetoresistance of sometimes more than 100%, however with equally large variation from device to device. Comparison with large area spin-valves indicates that the magnetoresistance of both large and small devices most likely originates from tunneling through pinholes and tunneling magnetoresistance.
Crystallographic investigation of Au nanoparticles embedded in a SrTiO3 thin film for plasmonics applications by means of synchrotron radiation
Authors: Pincini Davide , Mazzoli Claudio , Bernhardt Hendrik , Katzer Christian , Schmidl Frank , Uschmann Ingo , Detlefs Carsten
Published: March 2015

Self-organized monocrystalline Au nanoparticles with potential applications in plasmonics are grown in a SrTiO3 matrix by a novel two-step deposition process. The crystalline preferred orientation of these Au nanoparticles is investigated by synchrotron hard x-ray diffraction. Nanoparticles preferentially align with the (111) direction along the substrate normal (001), whereas two in-plane orientations are found with [110]SrTiO3∥[110]Au and [100]SrTiO3∥[110]Au. Additionally, a smaller diffraction signal from nanoparticles with the (001) direction parallel to the substrate normal (001) is observed; once again, two in-plane orientations are found, with [100]SrTiO3∥[100]Au and [100]SrTiO3∥[110]Au. The populations of the two in-plane orientations are found to depend on the thickness of the gold film deposited in the first step of the growth.
Divided-pulse nonlinear amplification and simultaneous compression
Authors: Hao Qiang , Zhang Qingshan , Sun Tingting , Chen Jie , Guo Zhanhua , Wang Yuqing , Guo Zhengru , Yang Kangwen , Zeng Heping
Published: March 2015

We report on a fiber laser system delivering 122 fs pulse duration and 600 mW average power at 1560 nm by the interplay between divided pulse amplification and nonlinear pulse compression. A small-core double-clad erbium-doped fiber with anomalous dispersion carries out the pulse amplification and simultaneously compresses the laser pulses such that a separate compressor is no longer necessary. A numeric simulation reveals the existence of an optimum fiber length for producing transform-limited pulses. Furthermore, frequency doubling to 780 nm with 240 mW average power and 98 fs pulse duration is achieved by using a periodically poled lithium niobate crystal at room temperature.
The enhancement mechanism of thin plasma layer on antenna radiation
Authors: Wang Chunsheng , Li Xueai , Jiang Binhao
Published: March 2015

A model of plasma-antenna is carried out to study the radiation enhancement mechanism of antenna covered by thin plasma layer. The results show when the radiation intensity achieves maximum, a region of equal electric field is formed due to the reflection of electric field at the interface of plasma and air. The plasma layer acted as an extension of the antenna. Furthermore, the shape of plasma layer is changed to verify the effect of plasma boundary on antenna radiation. The study shows the effect of thin plasma layer on electromagnetic field and provides a type of plasma antenna.
On the effect of alignment layers on blue phase liquid crystals
Authors: Joshi Pankaj , Shang Xiaobing , De Smet Jelle , Islamai Esma , Cuypers Dieter , Van Steenberge Geert , Van Vlierberghe Sandra , Dubruel Peter , De Smet Herbert
Published: March 2015

In the present work, the effect of alignment layers on blue phase liquid crystals was investigated. It was found that homogeneous alignment layers have profound selective influence on blue phase II (BPII). In the absence of alignment layers, BPII domains were randomly oriented and showed weak Bragg reflection in the UV, whereas with assistance of anchoring uniform domains with sharp Bragg reflection in the visible range appeared. On the other hand, the magnitude of Bragg shift in response to alignment layers in BPI is negligible. Domains of BP with alignment layers exhibit sharp Bragg reflection peaks (with FWHM < 15 nm), with very vivid colors and possessing fast switching speeds (<5 ×10−4 s). This simple method of selectively assisting one of the cubic phases is expected to be advantageous in the comparative studies of the two phases.
Surface plasmon resonance based integrable micro spectrometer
Authors: Ehlermann Jens , Siebels Jan , Fohrmann Simone , Mendach Stefan
Published: March 2015

We propose and realize the concept of a surface plasmon resonance based integrable and planar micro spectrometer that is suitable to determine the wavelength of incident light with sub-nanometer resolution over a broad range of frequencies in the infrared, visible, and ultraviolet regime. A dielectric grating structure with an ascending effective refractive index in the direction perpendicular to the periodicity is applied on top of a 20 nm thick gold film. Monochromatic light in normal incidence excites surface plasmons at confined areas on the sample so that the transmission is reduced locally. Depending on the wavelength, this area of low transmission shifts along the grating. The spatial transmission pattern provides information on the wavelength of the incident light.
Thermal expansion and its impacts on thermal transport in the FPU-α-β model
Authors: Cao Xiaodong , He Dahai , Zhao Hong , Hu Bambi
Published: March 2015

We study the impacts of thermal expansion, arising from the asymmetric interparticle potential, on thermal conductance in the FPU-α-β model. A nonmonotonic dependence of the temperature gradient and thermal conductance on the cubic interaction parameter α are shown, which corresponds to the variation of the coefficient of thermal expansion. Three domains with respect to α can be identified. The results are explained based on the detailed analysis of the asymmetry of the interparticle potential. The self-consistent phonon theory, which can capture the effect of thermal expansion, is developed to support our explanation in a quantitative way. Our result would be helpful to understand the issue that whether there exist normal thermal conduction in the FPU-α-β model.
Elimination of trench defects and V-pits from InGaN/GaN structures
Authors: Smalc-Koziorowska Julita , Grzanka Ewa , Czernecki Robert , Schiavon Dario , Leszczyński Mike
Published: March 2015

The microstructural evolution of InGaN/GaN multiple quantum wells grown by metalorganic chemical vapor phase epitaxy was studied as a function of the growth temperature of the GaN quantum barriers (QBs). We observed the formation of basal stacking faults (BSFs) in GaN QBs grown at low temperature. The presence of BSFs terminated by stacking mismatch boundaries (SMBs) leads to the opening of the structure at the surface into a V-shaped trench loop. This trench may form above an SMB, thereby terminating the BSF, or above a junction between the SMB and a subsequent BSF. Fewer BSFs and thus fewer trench defects were observed in GaN QBs grown at temperatures higher than 830 °C. Further increase in the growth temperature of the GaN QBs led to the suppression of the threading dislocation opening into V-pits.
Breakdown of the brain’s functional network modularity with awareness
Authors: Godwin Douglass , Barry Robert L. , Marois René
Published: March 2015

Significance

How the brain begets conscious awareness has been one of the most fundamental and elusive problems in neuroscience, psychology, and philosophy. Correspondingly, this problem has spawned a remarkably large number of theories that differ by the proposed extent of cortical and subcortical changes associated with awareness, ranging from local to global changes in functional connectivity. Graph theoretical techniques, in combination with functional magnetic resonance imaging, provide a well-suited tool to adjudicate between these disparate theories by characterizing whole-brain patterns of communication. In this paper, we demonstrate large-scale differences in functional connections with awareness of a visual target, consistent with global models of awareness.
Heme-thiolate ferryl of aromatic peroxygenase is basic and reactive
Authors: Wang Xiaoshi , Ullrich René , Hofrichter Martin , Groves John T.
Published: March 2015

Significance

The heme-thiolate peroxygenase of
Agrocybe aegerita
is a remarkably capable biocatalyst and a mechanistic analog of cytochrome P450. The stability of this fungal protein has provided a rare opportunity to study P450-like C−H hydroxylation in a novel and unrelated enzyme. Both APO-I and APO-II have been generated, and their redox potentials have been determined. The ferryl species Cys−S−Fe
IV
−OH (APO-II) has been generated cleanly via reduction of the corresponding APO-I and a basic p
K
a
revealed for the Cys−S−Fe
IV
−OH ⇄ Cys−S−Fe
IV
=O equilibrium. Most significantly, APO-II displays surprisingly high reactivity toward benzylic C−H (bond-dissociation energy 80−86 kcal/mol) and phenolic substrates with rate constants orders of magnitude larger than those of typical peroxidases or model compounds due to the basic ferryl.
Quantifying Avian Predation on Fish Populations: Integrating Predator‐Specific Deposition Probabilities in Tag Recovery Studies
Authors: Hostetter Nathan J. , Evans Allen F. , Cramer Bradley M. , Collis Ken , Lyons Donald E. , Roby Daniel D.
Published: March 2015

Accurate assessment of specific mortality factors is vital to prioritize recovery actions for threatened and endangered species. For decades, tag recovery methods have been used to estimate fish mortality due to avian predation. Predation probabilities derived from fish tag recoveries on piscivorous waterbird colonies typically reflect minimum estimates of predation due to an unknown and unaccounted‐for fraction of tags that are consumed but not deposited on‐colony (i.e., deposition probability). We applied an integrated tag recovery modeling approach in a Bayesian context to estimate predation probabilities that accounted for predator‐specific tag detection and deposition probabilities in a multiple‐predator system. Studies of PIT tag deposition were conducted across three bird species nesting at seven different colonies in the Columbia River basin, USA. Tag deposition probabilities differed significantly among predator species (Caspian terns Hydroprogne caspia: deposition probability = 0.71, 95% credible interval [CRI] = 0.51–0.89; double‐crested cormorants Phalacrocorax auritus: 0.51, 95% CRI = 0.34–0.70; California gulls Larus californicus: 0.15, 95% CRI = 0.11–0.21) but showed little variation across trials within a species or across years. Data from a 6‐year study (2008–2013) of PIT‐tagged juvenile Snake River steelhead Oncorhynchus mykiss (listed as threatened under the Endangered Species Act) indicated that colony‐specific predation probabilities ranged from less than 0.01 to 0.17 and varied by predator species, colony location, and year. Integrating the predator‐specific deposition probabilities increased the predation probabilities by a factor of approximately 1.4 for Caspian terns, 2.0 for double‐crested cormorants, and 6.7 for California gulls compared with traditional minimum predation rate methods, which do not account for deposition probabilities. Results supported previous findings on the high predation impacts from strictly piscivorous waterbirds nesting in the Columbia River estuary (i.e., terns and cormorants), but our findings also revealed greater impacts of a generalist predator species (i.e., California gulls) than were previously documented. Approaches used in this study allow for direct comparisons among multiple fish mortality factors and considerably improve the reliability of tag recovery models for estimating predation probabilities in multiple‐predator systems.

Received August 1, 2014; accepted November 11, 2014
The dark side of ERP implementations: narratives of domination, confusion and disruptive ambiguity
Authors: Kerr Don , Houghton Luke
Published: March 2015

This paper explores end-user perceptions of poorly implemented enterprise resource planning systems (ERP) from the perspective of a primary frontline user. This exploration analyses three case studies – from Australia, the United Kingdom and Denmark. Through these cases, we find three areas of concern: the reaction of implemented systems to existing work processes; the suspicion among workers that management has a hidden agenda in implementing an ERP system; and the perception that the implemented system is poorly aligned and leads to process duplication. The objective of this research is to see how ERP implementations have consequences that go beyond current research which, in the main, frames ERPs in a positive light and does not critically evaluate them. Our research demonstrates that, while major work groups in an organisation may appear to accommodate the ERP implementation, many individuals are very concerned about how the ERP disrupts their work. Our research demonstrates that there may be ‘dark’ consequences arising from an ERP implementation. These are likely to include unauthorised software development to fit previous work processes, confusion and little understanding of the new business processes. The result is an overall lack of trust in the efficacy of the system.
Glutamatergic Neurometabolites in Clozapine-Responsive and -Resistant Schizophrenia
Authors: Mcilwain Meghan Elizabeth , Anderson Valerie Margaret , Pillai Avinesh , Kydd Robert R , Russell Bruce R
Published: March 2015

Background

According to the current schizophrenia treatment guidelines, 3 levels of responsiveness to antipsychotic medication exist: those who respond to first-line antipsychotics, those with treatment-resistant schizophrenia who respond to clozapine, and those with clozapine-resistant or ultra-treatment resistant schizophrenia. Proton magnetic resonance spectroscopy studies indicate that antipsychotic medication decreases glutamate or total glutamate + glutamine in the brains of patients with schizophrenia and may represent a biomarker of treatment response; however, the 3 levels of treatment responsiveness have not been evaluated.

Methods

Proton magnetic resonance spectroscopy spectra were acquired at 3 Tesla from patients taking a second generation non-clozapine antipsychotic (first-line responders), patients with treatment-resistant schizophrenia taking clozapine, patients with ultra-treatment resistant schizophrenia taking a combination of antipsychotics, and healthy comparison subjects.

Results

Group differences in cerebrospinal fluid-corrected total glutamate + glutamine levels scaled to creatine were detected in the dorsolateral prefrontal cortex [df(3,48); F = 3.07, P = .04, partial η2 = 0.16] and the putamen [df(3,32); F = 2.93, P = .05, partial η2 = 0.22]. The first-line responder group had higher dorsolateral prefrontal cortex total glutamate + glutamine levels scaled to creatine than those with ultra-treatment resistant schizophrenia [mean difference = 0.25, standard error = 0.09, P = .04, family-wise error-corrected]. Those with treatment-resistant schizophrenia had higher total glutamate + glutamine levels scaled to creatine in the putamen than the first-line responders (mean difference = 0.31, standard error = 0.12, P = .05, family-wise error-corrected) and those with ultra-treatment-resistant schizophrenia (mean difference = 0.39, standard error = 0.12, P = .02, family-wise error-corrected).

Conclusions

Total glutamate + glutamine levels scaled to creatine in the putamen may represent a marker of response to clozapine. Future studies should investigate glutamatergic anomalies prior to clozapine initiation and following successful treatment.
Role of zinc-finger anti-viral protein in host defense against Sindbis virus
Authors: Kozaki Tatsuya , Takahama Michihiro , Misawa Takuma , Matsuura Yoshiharu , Akira Shizuo , Saitoh Tatsuya
Published: March 2015

Accumulating evidence indicates that type I interferon (IFN) mediates the host protective response to RNA viruses. However, the anti-viral effector molecules involved in this response have not been fully identified. Here, we show that zinc-finger anti-viral protein (ZAP), an IFN-inducible gene, plays a critical role in the elimination of Sindbis virus (SINV) in vitro and in vivo. The loss of ZAP greatly enhances the replication of SINV but does not inhibit type I IFN production in primary mouse embryonic fibroblasts (MEFs). ZAP binds and destabilizes SINV RNA, thereby suppressing the replication of SINV. Type I IFN fails to suppress SINV replication in ZAP-deficient MEFs, whereas the ectopic expression of ZAP is sufficient to suppress the replication of SINV in MEFs lacking the expression of type I IFN and the IFN-inducible genes. ZAP-deficient mice are highly susceptible to SINV infection, although they produce sufficient amounts of type I IFN. Therefore, ZAP is an RNA-sensing anti-viral effector molecule that mediates the type-I-IFN-dependent host defense against SINV.
ALotus japonicusCochaperone Protein Interacts With the Ubiquitin-Like Domain Protein CIP73 and Plays a Negative Regulatory Role in Nodulation
Authors: Kang Heng , Xiao Aifang , Huang Xiaoqin , Gao Xioumei , Yu Haixiang , He Xingxing , Zhu Hui , Hong Zonglie , Zhang Zhongming
Published: March 2015

The calcium/calmodulin-dependent protein kinase CCaMK forms a complex with its phosphorylation target CIP73 (CCaMK-interacting protein of 73 kDa). In this work, a homolog of the animal HSC/HSP70 interacting protein (HIP) was identified as an interacting partner of CIP73 in Lotus japonicus. L. japonicus HIP contains all functional domains characteristic of animal HIP proteins. The C-terminal STI1-like domain of L. japonicus HIP was found to be necessary and sufficient for interaction with CIP73. The interaction between CIP73 and HIP occurred in both the nuclei and cytoplasm in Nicotiana benthamiana leaf cells. The interactions between CIP73 and HIP and between CIP73 and CCaMK could take place simultaneously in the same nuclei. HIP transcripts were detected in all plant tissues tested. As nodule primordia developed into young nodules, the expression of HIP was down-regulated and the HIP transcript level became very low in mature nodules. More nodules were formed in transgenic hairy roots of L. japonicus expressing HIP RNA interference at 16 days postinoculation as compared with the control hairy roots expressing the empty vector. It appears that HIP may play a role as a negative regulator for nodulation.
The Novel Lipopeptide Poaeamide of the EndophytePseudomonas poaeRE*1-1-14 Is Involved in Pathogen Suppression and Root Colonization
Authors: Zachow Christin , Jahanshah Ghazaleh , de Bruijn Irene , Song Chunxu , Ianni Federica , Pataj Zoltán , Gerhardt Heike , Pianet Isabelle , Lämmerhofer Michael , Berg Gabriele , Gross Harald , Raaijmakers Jos M.
Published: March 2015

Endophytic Pseudomonas poae strain RE*1-1-14 was originally isolated from internal root tissue of sugar beet plants and shown to suppress growth of the fungal pathogen Rhizoctonia solani both in vitro and in the field. To identify genes involved in its biocontrol activity, RE*1-1-14 random mutagenesis and sequencing led to the identification of a nonribosomal peptide synthetase (NRPS) gene cluster predicted to encode a lipopeptide (LP) with a 10-amino-acid peptide moiety. The two unlinked gene clusters consisted of three NRPS genes, designated poaA (cluster 1) and poaB and poaC (cluster 2), spanning approximately 33.7 kb. In silico analysis followed by chemical analyses revealed that the encoded LP, designated poaeamide, is a structurally new member of the orfamide family. Poaeamide inhibited mycelial growth of R. solani and different oomycetes, including Phytophthora capsici, P. infestans, and Pythium ultimum. The novel LP was shown to be essential for swarming motility of strain RE*1-1-14 and had an impact on root colonization of sugar beet seedlings The poaeamide-deficient mutant colonized the rhizosphere and upper plant cortex at higher densities and with more scattered colonization patterns than the wild type. Collectively, these results indicate that Pseudomonas poae RE*1-1-14 produces a structurally new LP that is relevant for its antagonistic activity against soilborne plant pathogens and for colonization of sugar beet roots.
Resistance to the Ug99 Race Group of Puccinia graminis f. sp. tritici in Wheat–Intra/intergeneric Hybrid Derivatives
Authors: Kielsmeier-Cook Joshua , Danilova Tatiana V. , Friebe Bernd , Rouse Matthew N.
Published: March 2015

New races of Puccinia graminis f. sp. tritici, the causal agent of stem rust, threaten global wheat production. In particular, races belonging to the Ug99 race group significantly contribute to yield loss in several African nations. Genetic resistance remains the most effective means of controlling this disease. A collection of 546 wheat–intra- and intergeneric hybrids developed by W. J. Sando (United States Department of Agriculture, Beltsville, MD) was screened with eight races of P. graminis f. sp. tritici, including races TTKSK, TTKST, TTTSK, TRTTF, TTTTF, TPMKC, RKQQC, and QTHJC. There were 152 accessions resistant to one or more races and 29 accessions resistant to TTKSK, TTKST, and TTTSK. Of these 29 accessions, 9 were resistant to all races, 14 had infection type patterns that were indistinguishable from cultivars possessing Sr9h and Sr42, 2 were indistinguishable from accessions with SrTmp, and 4 did not display resistant patterns of accessions with any known Sr gene. Three accessions (604981, 605286, and 611932) characterized cytogenetically were disomic substitution lines, each with a single Thinopyrum ponticum chromosome pair. One accession (606057) was a disomic substitution or addition line with two pairs of T. ponticum chromosomes. In total, seven accessions are postulated to contain novel stem rust resistance genes. This research indicates the value of extant collections of wheat–intergeneric hybrids as sources of disease resistance genes.