bluuebunny/crossref_metadata_2025 huggingface dataset:
Tuning the crystal growth of perovskite thin-films by adding the 2-pyridylthiourea additive for highly efficient and stable solar cells prepared in ambient air
Authors: Sun Mengna , Zhang Fei , Liu Hongli , Li Xianggao , Xiao Yin , Wang Shirong
Published: April 2017

A rapid and simple process to prepare CH3NH3PbI3 perovskite solar cells in ambient air by adding 2-pyridylthiourea in the precursor solution was reported. The newly developed PSC exhibited an enhanced PCE of 18.2% along with enhanced stability under heat and humidity.
Metal–organic framework – derived Co9S8@CoS@CoO@C nanoparticles as efficient electro- and photo-catalysts for the oxygen evolution reaction
Authors: Long Jiying , Gong Yun , Lin Jianhua
Published: May 2017

Co9S8@CoS@CoO@C nanoparticles with photoresponse exhibit excellent electrocatalytic activity for the oxygen evolution reaction with a lower overpotential than RuO2and Pt.
CoOx–carbon nanotubes hybrids integrated on carbon cloth as a new generation of 3D porous hydrogen evolution promoters
Authors: Wang Jing , Wei Zhongzhe , Wang Haiyan , Chen Yiqing , Wang Yong
Published: April 2017

CoOx–CNT–CC electrodes not only displayed outstanding performance over a wide pH range, but also showed superb catalytic activity at low temperature.
A two-dimensional molecule with a large conjugation degree: synthesis, two-photon absorption and charge transport ability
Authors: Chen Dugang , Zhong Cheng , Zhao Yan , Nan Lingyan , Liu Yunqi , Qin Jingui
Published: May 2017

A 2D molecule OSPB demonstrated excimer emission in aqueous media and showed high 2PA performance in THF.
Human‐action recognition using a multi‐layered fusion scheme of Kinect modalities
Authors: Seddik Bassem , Gazzah Sami , Essoukri Ben Amara Najoua
Published: April 2017

This study addresses the problem of efficiently combining the joint, RGB and depth modalities of the Kinect sensor in order to recognise human actions. For this purpose, a multi‐layered fusion scheme concatenates different specific features, builds specialised local and global SVM models and then iteratively fuses their different scores. The authors essentially contribute in two levels: (i) they combine the performance of local descriptors with the strength of global bags‐of‐visual‐words representations. They are able then to generate improved local decisions that allow noisy frames handling. (ii) They also study the performance of multiple fusion schemes guided by different features concatenations, Fisher vectors representations concatenation and later iterative scores fusion. To prove the efficiency of their approach, they have evaluated their experiments on two challenging public datasets: CAD‐60 and CGC‐2014. Competitive results are obtained for both benchmarks.
Modular resonant DC/DC converter for DC grid system applications
Authors: Lin Bor‐Ren
Published: April 2017

A modular resonant DC/DC converter for DC microgrid system applications is provided in this study. Half‐bridge circuit cells are connected in series to reduce the voltage stress on each half‐bridge circuit, so that power metal–oxide–semiconductor field‐effect transistors with high‐frequency operation can be used at high‐voltage DC/DC converters and the converter size can be reduced. To balance input split voltages, flying capacitors are used and connected between each half‐bridge circuit. Therefore, input split voltages can be balanced automatically in each switching cycle without using the complexity control scheme. Resonant circuit is used in each half‐bridge cell to realise the zero‐voltage turn‐on for power switches and zero current turn‐off for rectifier diodes over the wide load range. Therefore, the proposed modular resonant DC/DC converter with high‐circuit efficiency can be achieved. The output sides of half‐bridge circuit cells are connected in parallel to reduce the current stress of all passive components. Finally, the circuit performance of the proposed converter is evaluated by experiments.
Comparative Study for Alignment of Extramedullary Guides versus Portable, Accelerometer-Based Navigation in Total Knee Arthroplasty
Authors: Matsumoto Kazu , Fukuta Masashi , Mori Nobuyuki , Akiyama Haruhiko , Ogawa Hiroyasu
Published: May 2017

The use of portable, accelerometer-based navigation (PN) devices for positioning of the components of total knee arthroplasty (TKA) is emerging as an alternative to standard extramedullary (EM) systems, which was needed to the image intensifier. The aim of our study was to compare the accuracy of component positioning in TKA using an EM and PN systems. Data from 100 consecutive primary TKAs, performed by multiple surgeons in 87 patients between October 2010 and June 2015, were analyzed. Coronal and sagittal plane alignments of the TKA components, relative to the mechanical axis of the limb, were evaluated by radiography. The mean postoperative coronal alignment angle of the femoral (α) and tibial (β) components was comparable between the groups (α: PN, 89.9 ± 2.2 degrees; EM, 89.9 ± 1.6 degrees and β: PN, 90.1 ± 1.4 degrees; EM, 89.6 ± 1.3 degrees). Groups were also comparable with regard to mean postoperative sagittal alignment angle of the femoral and tibial components (γ: PN, 2.3 ± 3.3 degrees; EM, 1.8 ± 1.7 degrees and σ: PN, 89.7 ± 2.5 degrees; EM, 90.1 ± 1.3 degrees). The incidence rate of a component malalignment > 3 degrees in the coronal and sagittal planes of the mechanical axis of the knee was comparable between the groups. In conclusion, the coronal and sagittal alignments for the femoral components was less accurate compared with tibial component alignment, especially in the PN group, and the sagittal alignment of the femoral component was less accurate than coronal alignment for both groups. Both the PN and EM systems provide satisfactory coronal and sagittal component alignments in TKA. Further technical improvement of the PN system could further improve its application for accurate component implantation in TKAs.
Effect of Transcutaneous Electric Nerve Stimulation on Pain after Total Knee Arthroplasty: A Blind Randomized Controlled Trial
Authors: Bautmans Ivan , Lefeber Nina , Lievens Pierre , Scheerlinck Thierry , Vaes Peter , Beckwée David
Published: May 2017

Transcutaneous electric nerve stimulation (TENS) has proven to be effective for postsurgical pain relief. However, there is a lack of well-constructed clinical trials investigating the effect of TENS after total knee arthroplasty (TKA). In addition, previous investigations reported that low- and high-frequency TENSs produced analgesic tolerance after 4 or 5 days of treatment. The aim of this study is to explore the effect of burst TENS on pain during hospitalization after TKA and to investigate whether burst TENS produces analgesic tolerance after 4 or 5 days of treatment. This stratified, triple blind, randomized controlled trial was approved by the University Hospital Brussels. Sixty-eight subjects were screened for eligibility before surgery; 54 were found eligible and 53 were included in the analyses. Patients were allocated to either a burst TENS or sham burst TENS group. TENS was applied daily during continuous passive mobilization. Knee pain intensity, knee range of motion, and analgesic consumption were assessed daily. Patients received burst TENS (N = 25) or sham burst TENS (N = 28). No significant differences in knee pain intensity were found between the groups (p > 0.05). Within the TENS and the sham TENS groups, the difference in knee pain before and after treatment did not evolve over time (p > 0.05). This study found no effects of burst TENS compared with sham burst TENS on pain during hospitalization after TKA.
Validity and Reliability of the Garmin Vector Power Meter in Laboratory and Field Cycling
Authors: Nimmerichter Alfred , Schnitzer Lukas , Prinz Bernhard , Simon Dieter , Wirth Klaus
Published: May 2017

To assess the validity and reliability of the Garmin Vector against the SRM power meter, 6 cyclists completed 3 continuous trials at power outputs from 100–300 W at 50–90 rev·min−1 and a 5-min time trial in laboratory and field conditions. In field conditions only, a 30-s sprint was performed. Data were compared with paired samples t-tests, with the 95% limits of agreement (LoA) and the typical error. Reliability was calculated as the coefficient of variation (CV). There was no significant difference between the devices in power output in laboratory (p=0.245) and field conditions (p=0.312). 1-s peak power was significantly different between the devices (p=0.043). The LoA were ~1.0±5.0 W and ~0.5±0.5 rev·min−1 in both conditions. The LoA during the 30-s sprint was 6.3±38.9 W and for 1-s peak power it was 18.8±17.1 W. The typical error for power output was 2.9%, while during sprint cycling it was 7.4% for 30-s and 2.7% for 1-s peak power. For cadence, the typical error was below 1.0%. The mean CVs were ~1.0% and ~3.0% for the SRM and Garmin, respectively. These findings suggest, that the Garmin Vector is a valid alternative for training. However, during sprint cycling there is lower agreement with the SRM power meter. Both devices provide good reliability (CV<3.0%).
Research Update: Hybrid energy devices combining nanogenerators and energy storage systems for self-charging capability
Authors: Kim Jeonghun , Lee Ju-Hyuck , Lee Jaewoo , Yamauchi Yusuke , Choi Chang Ho , Kim Jung Ho
Published: May 2017

The past decade has been especially creative for nanogenerators as energy harvesting devices utilizing both piezoelectric and triboelectric properties. Most recently, self-charging power units using both nanogenerators and energy storage systems have begun to be investigated for portable and wearable electronics to be used in our daily lives. This review focuses on these hybrid devices with self-charging combined with energy harvesting storage systems based on the most recent reports. In this research update, we will describe the materials, device structures, integration, applications, and research progress up to the present on hybrid devices.
Ultralow-energy electro-absorption modulator consisting of InGaAsP-embedded
photonic-crystal waveguide
Authors: Nozaki Kengo , Shakoor Abdul , Matsuo Shinji , Fujii Takuro , Takeda Koji , Shinya Akihiko , Kuramochi Eiichi , Notomi Masaya
Published: May 2017

Towards realizing highly integrable low-energy optical modulators, the small device capacitance (C) as well as the low driving voltage (Vpp) is demanded for suppressing the charging energy during the dynamic operation. Although an electro-absorption modulator (EAM) has great potential in reducing them, the additional energy associated with the photocurrent flow will limit the lower-bound of the consumption energy. In this work, a broadband EAM based on an InGaAsP-embedded photonic crystal waveguide is demonstrated, revealing a high modulation bit rate of up to 56 Gbit/s. The air-bridge structure and a device length of 100 μm or less result in a small C ≤ 13 fF while operating with Vpp < 1 V. Particularly, the operation in low reverse voltage for a p-i-n junction, that is, −0.2 V as the minimum value in this study, works effective for the reduction of energy involving the photocurrent. This results in the total electrical energy consumption of <2 fJ/bit, which is lower than that of any waveguide EAMs.
A “circularisation” method to repair deformations and determine the centre of velocity map images
Authors: Gascooke Jason R. , Gibson Stephen T. , Lawrance Warren D.
Published: May 2017

A problem besetting the analysis of velocity map images, particularly those of photoelectrons, is the presence of distortions that cause the features in the image to deviate from circularity, leading to a loss of resolution in the spectrum extracted. A method is presented to repair such distortions based on fitting the angular behaviour of each of the ring structures to a trigonometric expansion. The repair function allows the intensity at any value of radius and angle to be mapped to a new position that removes the distortion and returns the features to circular. While the method relies on the analysis of the structure in an image, it could also be applied to determine the “repair function” using a calibration image (or series of images) for the experiment. Once the image has been circularised it can be processed by any of the approaches that have been developed for that purpose. The analysis also enables the image centre to be determined with high accuracy. The fitting method utilises an inverse Abel transformation of the image in polar coordinates as a means to reshape the image into a series of spectral features in order to determine the radial position of features at each angle. Although the velocity distribution is not in general spherically symmetric and so this is not a mathematically correct means to extract the velocity distribution, the feature positions are accurately reproduced in the resulting spectrum while the intensity and anisotropy parameters can be remarkably close to those obtained using the proper inverse Abel transformation of the image.
Thermal diffusivity measurement of focused-ion-beam fabricated sample using photothermal reflectance technique
Authors: Hua Zilong , Ban Heng
Published: May 2017

Focused-Ion-Beam (FIB) can lift-off micrometer-sized samples from bulk materials for structural characterization and property measurement. The ability to determine thermophysical properties of such samples offers unique insight into the local microstructure-property relationship. A photothermal reflectance technique is developed to measure the thermal diffusivity of FIB-fabricated, micrometer-sized samples in this study. An analytic model is established to guide the experimental design and data analysis for the limited sample size and thickness. The thermal diffusivity of the sample can be extracted from a series of spatial-scan measurements at several modulated heating frequencies. To demonstrate the viability of the technique, a FIB-fabricated SiC plate with the size of 42 μm × 31 μm × 8 μm was used to represent high conductivity materials, which pose more challenges for the technique. The result compares favorably with literature values of SiC. The measurement uncertainty is quantified and possible experimental error sources are discussed. This technique is specially promising for thermal property measurements on nuclear fuels and materials.
Model microswimmers in channels with varying cross section
Authors: Malgaretti Paolo , Stark Holger
Published: May 2017

We study different types of microswimmers moving in channels with varying cross section and thereby interacting hydrodynamically with the channel walls. Starting from the Smoluchowski equation for a dilute suspension, for which interactions among swimmers can be neglected, we derive analytic expressions for the lateral probability distribution between plane channel walls. For weakly corrugated channels, we extend the Fick–Jacobs approach to microswimmers and thereby derive an effective equation for the probability distribution along the channel axis. Two regimes arise dominated either by entropic forces due to the geometrical confinement or by the active motion. In particular, our results show that the accumulation of microswimmers at channel walls is sensitive to both the underlying swimming mechanism and the geometry of the channels. Finally, for asymmetric channel corrugation, our model predicts a rectification of microswimmers along the channel, the strength and direction of which strongly depends on the swimmer type.
Effects of heat sink and source and entropy generation on MHD mixed convection of a Cu-water nanofluid in a lid-driven square porous enclosure with partial slip
Authors: Chamkha A. J. , Rashad A. M. , Mansour M. A. , Armaghani T. , Ghalambaz M.
Published: May 2017

In this work, the effects of the presence of a heat sink and a heat source and their lengths and locations and the entropy generation on MHD mixed convection flow and heat transfer in a porous enclosure filled with a Cu-water nanofluid in the presence of partial slip effect are investigated numerically. Both the lid driven vertical walls of the cavity are thermally insulated and are moving with constant and equal speeds in their own plane and the effect of partial slip is imposed on these walls. A segment of the bottom wall is considered as a heat source meanwhile a heat sink is placed on the upper wall of cavity. There are heated and cold parts placed on the bottom and upper walls, respectively, while the remaining parts are thermally insulated. Entropy generation and local heat transfer according to different values of the governing parameters are presented in detail. It is found that the addition of nanoparticles decreases the convective heat transfer inside the porous cavity at all ranges of the heat sink and source lengths. The results for the effects of the magnetic field show that the average Nusselt number decreases considerably upon the enhancement of the Hartmann number. Also, adding nanoparticles to a pure fluid leads to increasing the entropy generation for all values of D for λl=−λr= 1.
When can time-dependent currents be reproduced by the Landauer steady-state approximation?
Authors: Carey Rachel , Chen Liping , Gu Bing , Franco Ignacio
Published: May 2017

We establish well-defined limits in which the time-dependent electronic currents across a molecular junction subject to a fluctuating environment can be quantitatively captured via the Landauer steady-state approximation. For this, we calculate the exact time-dependent non-equilibrium Green’s function (TD-NEGF) current along a model two-site molecular junction, in which the site energies are subject to correlated noise, and contrast it with that obtained from the Landauer approach. The ability of the steady-state approximation to capture the TD-NEGF behavior at each instant of time is quantified via the same-time correlation function of the currents obtained from the two methods, while their global agreement is quantified by examining differences in the average currents. The Landauer steady-state approach is found to be a useful approximation when (i) the fluctuations do not disrupt the degree of delocalization of the molecular eigenstates responsible for transport and (ii) the characteristic time for charge exchange between the molecule and leads is fast with respect to the molecular correlation time. For resonant transport, when these conditions are satisfied, the Landauer approach is found to accurately describe the current, both on average and at each instant of time. For non-resonant transport, we find that while the steady-state approach fails to capture the time-dependent transport at each instant of time, it still provides a good approximation to the average currents. These criteria can be employed to adopt effective modeling strategies for transport through molecular junctions in interaction with a fluctuating environment, as is necessary to describe experiments.
A combined theoretical and experimental study of the valence and Rydberg states of iodopentafluorobenzene
Authors: Palmer Michael H. , Hoffmann Søren Vrønning , Jones Nykola C. , Coreno Marcello , de Simone Monica , Grazioli Cesare , Peterson Kirk A. , Baiardi Alberto , Zhang Teng , Biczysko Malgorzata
Published: May 2017

A new ultraviolet (UV) and vacuum ultraviolet (VUV) spectrum for iodopentafluorobenzene (C6F5I) using synchrotron radiation is reported. The measurements have been combined with those from a recent high-resolution photoelectron spectroscopic study. A major theoretical study, which includes both Franck-Condon (FC) and Herzberg-Teller (HT) analyses, leads to conclusions, which are compatible with both experimental studies. Our observation that the VUV multiplet at 7.926 eV in the VUV spectrum is a Rydberg state rather than a valence state leads to a fundamental reassignment of the VUV Rydberg spectrum over previous studies and removes an anomaly where some previously assigned Rydberg states were to optically forbidden states. Adiabatic excitation energies (AEEs) were determined from equations-of-motion coupled cluster with singles and doubles excitation; these were combined with time dependent density functional theoretical methods. Frequencies from these two methods are very similar, and this enabled the evaluation of both FC and HT contributions in the lower valence states. Multi-reference multi-root configuration interaction gave a satisfactory account of the principal UV+VUV spectral profile of C6F5I, with vertical band positions and intensities. The UV spectral onset consists of two very weak transitions assigned to 11B1 (πσ*) and 11B2 (σσ*) symmetries. The lowest unoccupied molecular orbital of a σ*(a1) symmetry has a significant C–I* antibonding character. This results in considerable lengthening of the C–I bond for both these excited states. The vibrational intensity of the lowest 11B1 state is dominated by HT contributions; the 11B2 state contains both HT and FC contributions; the third band, which contains three states, two ππ*(11A1, 21B2) and one πσ*(21B1), is dominated by FC contributions in the 1A1 state. In this 1A1 state, and the spectrally dominant bands near 6.7 (1A1) and 7.3 eV (1A1 + 1B2), the C–I bond length is in the normal range, and FC components dominate.
Note: Development of real-time epithermal neutron detector for boron neutron capture therapy
Authors: Tanaka H. , Sakurai Y. , Takata T. , Watanabe T. , Kawabata S. , Suzuki M. , Masunaga S.-I. , Taki K. , Akabori K. , Watanabe K. , Ono K.
Published: May 2017

The real-time detection of epithermal neutrons forms an important aspect of boron neutron capture therapy. In this context, we developed an epithermal neutron detector based on the combination of a small Eu:LiCaAlF6 scintillator and a quartz fiber in order to fulfill the irradiation-field requirements for boron neutron capture therapy. The irradiation test is performed with the use of a reactor-based neutron source. The thermal and epithermal neutron sensitivities of our epithermal neutron detector are estimated to be 9.52 × 10−8 ± 1.59 × 10−8 cm2 and 1.20 × 10−6 cm2 ± 8.96 × 10−9 cm2, respectively. We also subject the developed epithermal neutron detector to actual irradiation fields, and we confirm that the epithermal neutron flux can be measured in realtime.
Characterizing shock waves in hydrogel using high speed imaging and a fiber-optic probe hydrophone
Authors: Anderson Phillip A. , Betney M. R. , Doyle H. W. , Tully B. , Ventikos Y. , Hawker N. A. , Roy Ronald A.
Published: May 2017

The impact of a stainless steel disk-shaped projectile launched by a single-stage light gas gun is used to generate planar shock waves with amplitudes on the order of 102MPa in a hydrogel target material. These shock waves are characterized using ultra-high-speed imaging as well as a fiber-optic probe hydrophone. Although the hydrogel equation of state (EOS) is unknown, the combination of these measurements with conservation of mass and momentum allows us to calculate pressure. It is also shown that although the hydrogel behaves similarly to water, the use of a water EOS underpredicts pressure amplitudes in the hydrogel by ∼10% at the shock front. Further, the water EOS predicts pressures approximately 2% higher than those determined by conservation laws for a given value of the shock velocity. Shot to shot repeatability is controlled to within 10%, with the shock speed and pressure increasing as a function of the velocity of the projectile at impact. Thus the projectile velocity may be used as an adequate predictor of shock conditions in future work with a restricted suite of diagnostics.
A parametric investigation on the cyclotron maser instability driven by ring-beam electrons with intrinsic Alfvén waves
Authors: Tong Zi-Jin , Wang Chuan-Bing , Zhang Pei-Jin , Liu Jin
Published: May 2017

The electron-cyclotron maser is a process that generates the intense and coherent radio emission in the plasma. In this paper, we present a comprehensive parametric investigation on the electron-cyclotron-maser instability driven by non-thermal ring-beam electrons with intrinsic Alfvén waves, which pervade the solar atmosphere and interplanetary space. It is found that both forward propagating and backward propagating waves can be excited in the fast ordinary (O) and extraordinary (X) electromagnetic modes. The growth rates of X1 mode are almost always weakened by Alfvén waves. The average pitch-angle ϕ0 of electrons is a key parameter for the effect of Alfvén waves on the growth rate of modes O1, O2, and X2. For a beam-dominated electron distribution (ϕ0≲30°), the growth rates of the maser instability for O1, O2, and X2 modes are enhanced with the increase of the Alfvén wave energy density. In other conditions, the growth rates of O1, O2, and X2 modes weakened with the increasing Alfvén wave intensity, except that the growth of the O1 mode may also be enhanced by Alfvén waves for a ring distribution. The results may be important for us in analyzing the mechanism of radio bursts with various fine structures observed in space and astrophysical plasmas.
Hierarchy of stochastic Schrödinger equation towards the calculation of absorption and circular dichroism spectra
Authors: Ke Yaling , Zhao Yi
Published: May 2017

A theoretically solid and numerically exact method is presented for the calculation of absorption and circular dichroism (CD) spectra of molecular aggregates immersed in a harmonic bath constituted as the combination of some prominent quantized vibrational modes and continuous overdamped Brownian oscillators. The feasibility and the validity of newly proposed method are affirmed in the analytical monomer spectra. To go beyond the independent local bath approximation, all the correlations of site energy fluctuations and excitonic coupling fluctuations are included in our strategy, and their influence on the absorption and CD spectra is investigated based on the Frenkel exciton model of homodimer. In the end, a good fit of the absorption and part of CD spectra for the entire B800-B850 ring in the light-harvesting complexes 2 of purple bacteria to the experimental data is given, and the simulation results suggest that the asymmetry in the 800 nm region of CD spectra is actually an indication of B800-B850 inter-ring coupling.
Simultaneous measurement of film thickness, temperature, and mass fraction of urea-water-solutions by multi-wavelength laser absorption spectroscopy
Authors: Yang Huinan , Shi Jianwei , Su Mingxu , Wu Wei , Cai Xiaoshu
Published: May 2017

Quantitative analysis for thickness, temperature, and mass fraction of liquid film is extremely crucial to the relevant industrial processes, but these parameters cannot be determined simultaneously by conventional measurement techniques. In the present work, a novel measurement method based on laser absorption spectroscopy was developed to measure the film temperature, thickness, and mass fraction of urea–water-solutions simultaneously by combining three wavelengths, 1420 nm, 1488 nm, and 1531 nm. Moreover, measurement accuracy of this method was validated by a calibration tool which provided liquid film with known film thickness, temperature, and mass fraction, respectively. It revealed that the deviation between the measured and known parameters with the developed method was 0.86%, 4.58%, and 3.85%, respectively.
Photoinduced effects in field electron emission from diamond needles
Authors: Porshyn V. , Kleshch V. I. , Obraztsova E. A. , Chuvilin A. L. , Lützenkirchen-Hecht D. , Obraztsov A. N.
Published: May 2017

We report an explicit experimental observation of photostimulated electron field emission from diamond. The electron emission properties of monocrystalline diamond needles were investigated in the dark and under illumination by nanosecond laser pulses. A prominent increase in the electron emission current was detected under illumination by light with photon energies above 5.0 eV. The linear dependence of the photoinduced emission current on the light intensity was observed in the spectral range of 5.0 to 5.9 eV, while its field dependence demonstrated saturation behavior. The remarkable feature of the observed phenomenon was the fact that illuminated and field emission areas of the diamond needles were spatially separated by about 100 μm in the used experimental setup. Possible mechanisms for the observed effects are discussed.
SFG analysis of the molecular structures at the surfaces and buried interfaces of PECVD ultralow-dielectric constant pSiCOH: Reactive ion etching and dielectric recovery
Authors: Myers John N. , Zhang Xiaoxian , Huang Huai , Shobha Hosadurga , Grill Alfred , Chen Zhan
Published: May 2017

Molecular structures at the surface and buried interface of an amorphous ultralow-k pSiCOH dielectric film were quantitatively characterized before and after reactive ion etching (RIE) and subsequent dielectric repair using sum frequency generation (SFG) vibrational spectroscopy and Auger electron spectroscopy. SFG results indicated that RIE treatment of the pSiCOH film resulted in a depletion of ∼66% of the surface methyl groups and changed the orientation of surface methyl groups from ∼47° to ∼40°. After a dielectric recovery process that followed the RIE treatment, the surface molecular structure was dominated by methyl groups with an orientation of ∼55° and the methyl surface coverage at the repaired surface was 271% relative to the pristine surface. Auger depth profiling indicated that the RIE treatment altered the top ∼25 nm of the film and that the dielectric recovery treatment repaired the top ∼9 nm of the film. Both SFG and Auger profiling results indicated that the buried SiCNH/pSiCOH interface was not affected by the RIE or the dielectric recovery process. Beyond characterizing low-k materials, the developed methodology is general and can be used to distinguish and characterize different molecular structures and elemental compositions at the surface, in the bulk, and at the buried interface of many different polymer or organic thin films.
Widely tunable narrow-linewidth 1.5 μm light source based on a monolithically integrated quantum dot laser array
Authors: Becker A. , Sichkovskyi V. , Bjelica M. , Rippien A. , Schnabel F. , Kaiser M. , Eyal O. , Witzigmann B. , Eisenstein G. , Reithmaier J. P.
Published: May 2017

A monolithically integrated widely tunable narrow-linewidth light source was realized on an InP-based quantum dot (QD) gain material. The quasi zero-dimensional nature of QDs and the resulting low linewidth enhancement factor enabled standalone distributed feedback (DFB) lasers with intrinsic linewidths as low as 110 kHz. An integrated device comprising four DFB lasers with on-chip micro-heaters, a 3 dB-coupler network, and a semiconductor optical amplifier (SOA), which covers the entire C+ telecom band, exhibits a linewidth of below 200 kHz independent of the SOA operation current.
Fano resonance based ultra high-contrast electromagnetic switch
Authors: Amin Muhammad , Ramzan Rashad , Siddiqui Omar
Published: May 2017

We experimentally achieve highly asymmetrical enhanced-Q Fano resonances in metallic electromagnetic structures fabricated on conductive planes. We show that the complete destructive interference mechanism of the dark and bright resonant modes generated by a pair of electromagnetically coupled open-ended conductive arms can lead to the asymmetric resonance characterized by a near-unity transparency window followed by a deep scattering band. With the incorporation of a variable capacitor between the coupled metallic strips, the dynamic tunability of the resonant modes is achieved, which can be exploited in high isolation switches and modulators in the GHz spectrum. The switching contrast of over 50 dB achieved through Fano resonance is much higher considering its compact size (i.e., the transmission path is much smaller than the wavelength λ/30). The dispersion based tunable Fano switch offers several advantages over conventional microelectromechanical system and CMOS based switches.
Macroscopic model for analyzing the electro-optics of uniform lying helix cholesteric liquid crystals
Authors: Tan Guanjun , Lee Yun-Han , Gou Fangwang , Hu Minggang , Lan Yi-Fen , Tsai Cheng-Yeh , Wu Shin-Tson
Published: May 2017

A macroscopic model is developed for analyzing the electro-optics of short-pitch uniform lying helix (ULH) cholesteric liquid crystals (CLCs). Both flexoelectric effect and dielectric effect make important contributions to the maximum transmittance and operation voltage of the ULH devices. Based on the proposed macroscopic approximation, we derive an analytical expression to quantitatively evaluate the relative strength of these two effects. Very good agreement between theory and experiment is achieved. We also investigate the viewing angle of ULH CLC displays and find that their viewing angle characteristics are similar to those of conventional in-plane switching liquid crystal displays.
Plasmonic lattice resonance-enhanced light emission from plastic scintillators by periodical Ag nanoparticle arrays
Authors: Liu Bo , Zhu Zhichao , Wu Qiang , Cheng Chuanwei , Gu Mu , Xu Jun , Chen Hong , Liu Jinliang , Chen Liang , Ouyang Xiaoping
Published: May 2017

We have demonstrated that periodical arrays of silver nanoparticles can enhance the light emission from a plastic scintillator layer on the surface of a silicon substrate. The enhancement is attributed to surface lattice resonances with a photonic-plasmonic nature. Although the enhancement exhibits directional characteristics for individual wavelengths, the wavelength-integrated enhancement shows a monotonous increase with increasing emission angle. As a result, an overall 1.81-fold wavelength- and angle-integrated enhancement has been obtained. This observation is promising for fundamental and applied research into enhanced luminescent material layers on opaque substrates.
A high accuracy algorithm of displacement measurement for a micro-positioning stage
Authors: Zhang Xiang , Zhang Xianmin , Wu Heng , Gan Jinqiang , Li Hai
Published: May 2017

A high accuracy displacement measurement algorithm for a two degrees of freedom compliant precision micro-positioning stage is proposed based on the computer micro-vision technique. The algorithm consists of an integer-pixel and a subpixel matching procedure. Series of simulations are conducted to verify the proposed method. The results show that the proposed algorithm possesses the advantages of high precision and stability, the resolution can attain to 0.01 pixel theoretically. In addition, the consuming time is reduced about 6.7 times compared with the classical normalized cross correlation algorithm. To validate the practical performance of the proposed algorithm, a laser interferometer measurement system (LIMS) is built up. The experimental results demonstrate that the algorithm has better adaptability than that of the LIMS.
Proton structure seen in a new light
Authors: Blau Steven K.
Published: May 2017

New evidence of two-photon exchange could reconcile discrepant measurements of the proton’s inner construction.
Steady, strong growth is expected for open-access journals
Authors: Kramer David
Published: May 2017

Publishing models continue evolving to accommodate government mandates. Meanwhile, publishers look to cope with article-sharing sites that affect their business.
US academic fusion researchers sound alarm
Authors: Feder Toni
Published: May 2017

Forming new modes of university leadership using off-campus facilities is essential to sustain the field.
Imaging cancer with photoacoustic radar
Authors: Mandelis Andreas
Published: May 2017

An 80-year-old technology best known for locating planes in the sky is inspiring new methods to spot tumors before they become malignant.
Changes in leaf stomatal conductance, petiole hydraulics and vessel morphology in grapevine (Vitis vinifera cv. Chasselas) under different light and irrigation regimes
Authors: Dayer Silvina , Peña Jorge Perez , Gindro Katia , Torregrosa Laurent , Voinesco Francine , Martínez Liliana , Prieto Jorge A. , Zufferey Vivian
Published: May 2017

Hydraulic conductance and water transport in plants may be affected by environmental factors, which in turn regulate leaf gas exchange, plant growth and yield. In this study, we assessed the combined effects of radiation and water regimes on leaf stomatal conductance (gs), petiole specific hydraulic conductivity (Kpetiole) and anatomy (vessel number and size); and leaf aquaporin gene expression of field-grown grapevines at the Agroscope Research Station (Leytron, Switzerland). Chasselas vines were subjected to two radiation (sun and shade) levels combined with two water (irrigated and water-stressed) regimes. The sun and shade leaves received ~61.2 and 1.48 mol m–2 day–1 of photosynthetically active radiation, respectively, during a clear-sky day. The irrigated vines were watered weekly from bloom to veraison whereas the water-stressed vines did not receive any irrigation during the season. Water stress reduced gs and Kpetiole relative to irrigated vines throughout the season. The petioles from water-stressed vines showed fewer large-sized vessels than those from irrigated vines. The shaded leaves from the irrigated vines exhibited a higher Kpetiole than the sun leaves at the end of the season, which was partially explained by a higher number of vessels per petiole and possibly by the upregulation of some of the aquaporins measured in the leaf. These results suggest that not only plant water status but also the light environment at the leaf level affected leaf and petiole hydraulics.
Demographic evaluation of translocating the threatened northern quoll to two Australian islands
Authors: Griffiths Anthony D. , Rankmore Brooke , Brennan Kym , Woinarski John C. Z.
Published: May 2017

Context Translocation is widely used to help avoid extinction of species from threatening processes. A fundamental objective of translocation is to establish self-sustaining populations; estimating demographic parameters is critical to assessing success of these programs and can also be used to support future management actions. Aims We estimated demographic parameters to evaluate the success of translocating the northern quoll Dasyurus hallucatus to two islands (Astell and Pobassoo), in response to the threat posed by the introduced cane toad Rhinella marina on the Australian mainland. Methods We used capture–mark–recapture methods to monitor both populations at regular intervals from initial release in 2003 until 2009 and a one-off survey in 2014. Key results Relative abundance (trap success) increased exponentially in the first 4 years, declined, and then stabilised in subsequent years. The population of female northern quolls on Astell Island peaked in 2006 with an estimate of 3640 (95% CI 3022–4257), and on Pobassoo Island the peak was 2007 with 617 (95% CI 531–703) females. In 2014 the population had decreased to 2193 (95% CI 1920–2467) on Astell and 451 (95% CI 359–543) on Pobassoo. Apparent survival and body condition decreased significantly following the population peak, possibly related to density dependence. Conclusion Both populations of northern quolls reached their regulation phase after going through establishment and growth phases, which included exceeding carrying capacity. The pattern was similar between the populations. Implications Increased survival and recruitment at threat-free translocation sites contributes to successful establishment of self-sustaining populations.
A transit-amplifying population underpins the efficient regenerative capacity of the testis
Authors: Carrieri Claudia , Comazzetto Stefano , Grover Amit , Morgan Marcos , Buness Andreas , Nerlov Claus , O’Carroll Dónal
Published: May 2017

The spermatogonial stem cell (SSC) that supports spermatogenesis throughout adult life resides within the GFRα1-expressing A type undifferentiated spermatogonia. The decision to commit to spermatogenic differentiation coincides with the loss of GFRα1 and reciprocal gain of Ngn3 (Neurog3) expression. Through the analysis of the piRNA factor Miwi2 (Piwil4), we identify a novel population of Ngn3-expressing spermatogonia that are essential for efficient testicular regeneration after injury. Depletion of Miwi2-expressing cells results in a transient impact on testicular homeostasis, with this population behaving strictly as transit amplifying cells under homeostatic conditions. However, upon injury, Miwi2-expressing cells are essential for the efficient regenerative capacity of the testis, and also display facultative stem activity in transplantation assays. In summary, the mouse testis has adopted a regenerative strategy to expand stem cell activity by incorporating a transit-amplifying population to the effective stem cell pool, thus ensuring rapid and efficient tissue repair.
Factors related to the decline and rebuilding of billfish stocks in the Atlantic and Indian oceans
Authors: Sharma Rishi , Pons Maite , Martin Sarah , Kell Laurie , Walter John , Lauretta Matthew , Schirripa Michael
Published: April 2017

The article examines factors related to the decline and rebuilding of billfish stocks in the Atlantic and Indian oceans. Longline effort has declined over the last 10–15 years in both oceans. This decline in fishing pressure has led to the recovery of some stocks, but some species that are caught incidentally in industrial longline fisheries remain overexploited. Using a simple moving average technique on fishing mortality trajectories, we estimated a threshold effort size of 240 million hooks for the Atlantic Ocean and 364 million hooks for the Indian Ocean where stocks start experiencing overfishing. In addition, we highlight differences in the economic characteristics of the major fleets catching billfish in the two oceans and discuss how this may be associated with differences in management, enforcement, and stock rebuilding.
A broad spectral feature detected during the cooling phase of a type I X-ray burst from GRS 1747−312 with Suzaku
Authors: Iwai Masachika , Dotani Tadayasu , Ozaki Masanobu , Maeda Yoshitomo , Mori Hideyuki , Saji Shigetaka
Published: April 2017

We analyzed the Suzaku archive data of a type I X-ray burst from GRS 1747−312, a low-mass X-ray binary located in the globular cluster Terzan 6. During the Galactic bulge mapping observations with Suzaku, which covered Terzan 6, an X-ray burst of long duration and with moderate photospheric-radius expansion was serendipitously detected and was considered to be most probably originating from GRS 1747−312. The time-divided burst spectra were reproduced well with an absorbed blackbody over the majority of the time, but significant deviation was detected late in the cooling phase. The deviation was due to a rolled-off feature, which gradually developed in the cooling phase of the burst, in the energy spectra above ∼7 keV. We tested various models to reproduce the spectral feature and found three types of models (reflection by cold matter, partial-covering absorption, and Doppler-smeared absorption edges due to the rapid spin of a neutron star) gave a statistically acceptable fit. We discussed the feasibility of these models, including a non-Planckian nature of the burst spectra.
Chloroplast Hsp70 Isoform Is Required for Age-Dependent Tissue Preference ofBamboo mosaic virusin MatureNicotiana benthamianaLeaves
Authors: Huang Ying Wen , Hu Chung Chi , Tsai Ching Hsiu , Lin Na Sheng , Hsu Yau Heiu
Published: May 2017

Plant viruses may exhibit age-dependent tissue preference in their hosts but the underlying mechanisms are not well understood. In this study, we provide several lines of evidence to reveal the determining role of a protein of the Nicotiana benthamiana chloroplast Hsp70 (NbcpHsp70) family, NbcpHsp70-2, involved in the preference of Bamboo mosaic virus (BaMV) to infect older tissues. NbcpHsp70 family proteins were identified in complexes pulled down with BaMV replicase as the bait. Among the isoforms of NbcpHsp70, only the specific silencing of NbcpHsp70-2 resulted in the significant decrease of BaMV RNA in N. benthamiana protopalsts, indicating that NbcpHsp70-2 is involved in the efficient replication of BaMV RNA. We further identified the age-dependent import regulation signal contained in the transit peptide of NbcpHsp70-2. Deletion, overexpression, and substitution experiments revealed that the signal in the transit peptide of NbcpHsp70-2 is crucial for both the import of NbcpHsp70-2 into older chloroplasts and the preference of BaMV for infecting older leaves of N. benthamiana. Together, these data demonstrated that BaMV may exploit a cellular age-dependent transportation mechanism to target a suitable environment for viral replication.
International/Institutional Trauma in Developmental Pediatric Practice
Authors: Pappas Demetra , Fogler Jason , Sargado Sabrina , Welchons Leah , Augustyn Marilyn
Published: April 2017

CASE: “Aabis” is a school-aged boy from a predominantly conservative Muslim nation who presented to a tertiary developmental-behavioral pediatric (DBP) clinic to seek “expert opinion” for significant social and learning difficulties in the context of a history of frequent falling and “clumsiness.” He was seen by a psychiatrist in his home country, who ordered an electroencephalogram and “brain map” (both normal), and received occupational and physical therapies. Frequent tantrums and intense emotional reactions to minor events—revealed to be related to a history of repeated physical beatings from groups of his “friends”—prompted referral to the DBP clinic. When asked why he did not fight back, Aabis said that he did not want to lose his friends. He and his parents further explained that this kind of organized aggression is considered part of normative development in their country and that Aabis needed to “toughen up.”

Aabis was described by his parents as being very “sensitive” when others raised their voices, shivering when reprimanded and profusely apologizing for real and imagined mistakes. He bit his nails until they bled, washed his hands repetitively, and changed his clothes several times per day. On witnessing his parents arguing, Aabis threatened to harm himself with a decorative knife.

The assessment presented with several procedural complications specifically the use of an interpreter and the cultural differences regarding many of the topics discussed. Aabis spoke very little English, and an interpreter was not available in person on the initial day of the assessment. Telephonic phone translation services were attempted, but there were concerns that Aabis would not feel comfortable with sharing his emotions over the phone with an unidentified individual. As feared, Aabis was resistant to discuss emotionally charged topics (e.g., feeling sad, being bullied, hearing or seeing things) and grew impatient and irritated with the phone interpreter. After some unsuccessful experimentation with a Google-based translation system (implemented at Aabi's request to help build comfort and rapport), a second telephonic interpreter was brought into the session, who Aabis later described to his parents as “mean.” (Aabis clarified that the second interpreter had been brusque and insensitive to his tentative attempts to express his feelings, e.g., by telling him to “Speak up. Spit it out.”)

Toward the end of the interview, Aabis seemed to dissociate and insisted anxiously that he did not want to relay certain information without his parents present in the room. What would you do next in this situation?

Details about this case, including name and age, have been altered to protect the child's identity.