bluuebunny/crossref_metadata_2025 huggingface dataset:
A highly sensitive flexible SnS thin film photodetector in the ultraviolet to near infrared prepared by chemical bath deposition
Authors: Mahdi Mohamed S. , Ibrahim K. , Hmood A. , Ahmed Naser M. , Azzez Shrook A. , Mustafa Falah I.
Published: December 2016

A novel flexible broad band UV-vis-NIR SnS photodetector with high photosensitivity and fast response time for scientific and industrial applications.
Correction: A modified Sips distribution for use in adsorption isotherms and in fractal kinetic studies
Authors: Debord Jean , Harel Michel , Cheknane Benamar , Bollinger Jean-Claude , Bouras Omar
Published: December 2016

Correction for ‘A modified Sips distribution for use in adsorption isotherms and in fractal kinetic studies’ by Jean Debord et al., RSC Adv., 2016, 6, 66266–66274.
Inhibition of SIK2 and SIK3 during differentiation enhances the anti-inflammatory phenotype of macrophages
Authors: Darling Nicola J. , Toth Rachel , Arthur J. Simon C. , Clark Kristopher
Published: December 2016

The salt-inducible kinases (SIKs) control a novel molecular switch regulating macrophage polarization. Pharmacological inhibition of the SIKs induces a macrophage phenotype characterized by the secretion of high levels of anti-inflammatory cytokines, including interleukin (IL)-10, and the secretion of very low levels of pro-inflammatory cytokines, such as tumour necrosis factor α. The SIKs, therefore, represent attractive new drug targets for the treatment of macrophage-driven diseases, but which of the three isoforms, SIK1, SIK2 or SIK3, would be appropriate to target remains unknown. To address this question, we developed knock-in (KI) mice for SIK1, SIK2 and SIK3, in which we introduced a mutation that renders the enzymes catalytically inactive. Characterization of primary macrophages from the single and double KI mice established that all three SIK isoforms, and in particular SIK2 and SIK3, contribute to macrophage polarization. Moreover, we discovered that inhibition of SIK2 and SIK3 during macrophage differentiation greatly enhanced the production of IL-10 compared with their inhibition in mature macrophages. Interestingly, macrophages differentiated in the presence of SIK inhibitors, MRT199665 and HG-9-91-01, still produced very large amounts of IL-10, but very low levels of pro-inflammatory cytokines, even after the SIKs had been reactivated by removal of the drugs. Our data highlight an integral role for SIK2 and SIK3 in innate immunity by preventing the differentiation of macrophages into a potent and stable anti-inflammatory phenotype.
Subwavelength T‐slot waveguide optical interconnect
Authors: Priye V. , Kumar V.
Published: December 2016

A T‐slot waveguide optical interconnect is proposed that can be realised on a photonic integrated circuit with sub – wavelength silicon slot waveguides and can redirect optical power to optical devices placed perpendicular to each other. In the proposed configuration, all critical parameters of high index waveguide and low index slot of all three arms are optimised. A power splitting efficiency of 54% is achieved which is almost independent of operating International Telegraph Union (ITU) grid C Band wavelengths. By judicious modification in T‐slot waveguide configuration, power splitting efficiency is enhanced up to 73%.
260‐GHz differential amplifier in SiGe heterojunction bipolar transistor technology
Authors: Yoon D. , Seo M.‐G. , Song K. , Kaynak M. , Tillack B. , Rieh J.‐S.
Published: December 2016

A 260‐GHz amplifier in a SiGe heterojunction bipolar transistor (HBT) technology is reported. It is based on three‐stage differential cascode topology and adopts a passive shunt transistor pair at the output of each amplifying stage to relax instability caused by parasitic base inductance of amplifying transistor pair. The instability of the amplifier can be mitigated by tuning the base bias voltage of the shunt transistor pair. Peak gain of the amplifier was measured as 15 dB at 260 GHz. DC power dissipation is 112 mW. The chip occupies 300 × 160 μm2 excluding Baluns and probing pads.
Robust guaranteed cost consensus for high‐order discrete‐time multi‐agent systems with parameter uncertainties and time‐varying delays
Authors: Xu Jun , Zhang Guoliang , Zeng Jing , Xi Jianxiang , Du Boyang
Published: December 2016

The robust guaranteed cost consensus problem of high‐order discrete‐time linear multi‐agent systems (MASs) with parameter uncertainties and time‐varying delays is studied, and a linear consensus protocol of it is designed. Norm‐bounded uncertainties and polytopic uncertainties are considered. First, the idea of robust guaranteed cost control is introduced into consensus problems for the MASs, where a cost function is defined based on state errors among neighbouring agents and control inputs of all the agents. Second, by constructing suitable Lyapunov functions and using the stability theory of discrete‐time linear systems, two sufficient linear matrix inequality conditions are derived to insure that high‐order discrete‐time linear MASs with the two types of parameter uncertainties and time‐varying delays reach robust guaranteed cost consensus. At the same time, two upper bounds of the guaranteed cost function are also given. Third, convergence results are given as final consensus values of the MASs with parameter uncertainties and time‐varying delays. Finally, two numerical comparisons are given to illustrate the correctness and availability of the theoretical results.
Fast algorithm for hybrid region‐based active contours optimisation
Authors: Boutiche Yamina , Abdesselam Abdelhamid
Published: December 2016

Active contours are usually based on the optimisation of energy functionals that are built to attract the curve towards the objects' boundaries. This study describes a hybrid region‐based active contours technique that uses global means to define the global fitting energy and local means and variances to define the local fitting energy. The optimisation of the functional is performed by applying a sweeping‐principle algorithm, which avoids solving any partial differential equation and removes the need for any stability conditions. Furthermore, sweeping‐principle algorithm is not based on the computation of derivatives, which allows using a binary level set function during the minimisation process instead of the signed distance function, consequently this removes the need for the distance regularisation term, avoiding its subtle side effects and speeding up the optimisation process. Successful and accurate segmentation results are obtained on synthetic and real images with a significant gain in the CPU execution time when compared with the minimisation via the commonly used gradient descent method.
Theory, analysis and design of high order reflective, absorptive filters
Authors: Bulja Senad , Grebennikov Andrei , Rulikowski Pawel
Published: December 2016

In this study, design methodology and equations necessary for low‐loss high‐order absorptive filters in the reflective‐type configuration are introduced, derived and described in detail. Initially, a simple single, absorptive filter is described and its use in radio frequency front‐ends is discussed. Based on this, improvements to the single, first‐order absorptive filter are discussed and novel circuits that cater for lower loss higher‐order absorptive filters are proposed. The necessary conditions for the achievement of the proposed higher‐order absorptive filters from the proposed circuits are derived in order to establish the potential of the proposed circuits. As an experimental verification, first‐, second‐ and third‐order reflective‐type absorptive filters are fabricated and their performances measured. In particular, in the case of a third‐order absorptive filter, it is shown that the depth of the introduced attenuation is at least 27.4 dB across the frequency range of 2.17–2.27 GHz. Further, the use of the obtained absorptive filters was put to a test by inserting them in series with a commercially available band‐pass filter.
Systematic approach to sidelobe reduction in linear antenna arrays through corporate‐feed‐controlled excitation
Authors: Ogurtsov Stanislav , Koziel Slawomir
Published: December 2016

A systematic approach to sidelobe reduction of broadside linear antenna arrays by design of corporate feeds implementing non‐uniform excitation is proposed. The approach comprises of the two major stages. First, candidate excitation sets (corporate feeds) are searched among excitation sets which might energize a particular array aperture. The range of the corporate networks is restricted – based on the implementation and performance considerations – to the ones constructed using only T‐junctions with equal power split. The reference for the candidates in terms of the sidelobe level is the uniformly excited and spaced array aperture with the same number of elements. The search is performed over realizable excitations and constrained elements’ spacings using the array factor and the model of excitation amplitudes due to corporate feeding. At the second stage, an excitation providing reduced sidelobes and simple routing is implemented as a microstrip corporate feed within the antenna array model. The entire antenna‐feed circuit is adjusted and validated using numerical optimization and discrete electromagnetic simulations at the high‐fidelity level of description. The proposed feeds and the approach to their systematic design offer flexibility in design of linear antenna arrays without extra complications and allow substantial sidelobe reduction. A demonstration example is provided.
Robust speed measurements with standard wireless devices
Authors: Schneider Johannes , Caracas Alexandru
Published: December 2016

Speed measurements are crucial for controlling traffic and in supporting automation of industrial processes. The speed of moving objects is typically measured from a stationary position using time‐of‐flight or the Doppler effect. Existing approaches require either relatively bulky physical devices or complex signal processing. The authors propose a new method for measuring the speed of (metal) objects moving on a fixed track. The authors’ method is applicable, e.g. to cars on a road, trains on rails, or goods sliding on a conveyor belt. The method relies on the constructive and destructive interference patterns created by the reflections from the moving target. Speed is determined by measuring the signal strength of received messages as perceived by standard wireless devices. The method requires only minimal signal processing and only two commodity wireless transceivers, which are independent of the moving target. The advantages of their system compared to other technologies are reduced size, reduced cost, and in some scenarios robustness.
Plasma treatment effect on angiogenesis in wound healing process evaluated in vivo using angiographic optical coherence tomography
Authors: Kim D. W. , Park T. J. , Jang S. J. , You S. J. , Oh W. Y.
Published: December 2016

Non-thermal atmospheric pressure plasma holds promise for promoting wound healing. However, plasma-induced angiogenesis, which is important to better understand the underlying physics of plasma treatment effect on wound healing, remains largely unknown. We therefore evaluated the effect of non-thermal plasma on angiogenesis during wound healing through longitudinal monitoring over 30 days using non-invasive angiographic optical coherence tomography imaging in vivo. We demonstrate that the plasma-treated vascular wound area of mouse ear was noticeably decreased as compared to that of control during the early days in the wound healing process. We also observed that the vascular area density was increased in the plasma affected region near the wound as compared to the plasma unaffected region. The difference in the vascular wound area and the vascular area density peaked around day 3. This indicates that the plasma treatment induced additional angiogenic effects in the wound healing process especially during the early days. This non-invasive optical angiographic approach for in vivo time-lapse imaging provides further insights into elucidating plasma-induced angiogenesis in the wound healing process and its application in the biomedical plasma evaluation.
Structural transition and its effect in La, Zr co-substituted mono-domain BiFeO3
Authors: Usama Hasan M. , Sharif Ahmed , Zubair M. A. , Gafur M. A. , Hoque Sheikh Manjura
Published: December 2016

A new approach was employed in explaining the weak ferromagnetic behavior of conventionally synthesized Zr4+ modified Bi0.8La0.2FeO3. Rietveld refinement of XRD patterns revealed a polar-to-non-polar R3c → Pnma structural transition in Zr4+substituted samples. Magnetic properties were discovered to be remarkably enhanced, with extracted coercivity and remanence as high as 14 kOe and 0.2 emu/g, respectively. More importantly, an answer to the essential question of the magnetic domain state of the samples has been put forward. Our analysis established, nearly without doubt, the presence of grains consisting of a single magnetic domain. Separated ferromagnetic and anti-ferromagnetic components of the total M-H curves helped to reveal an immense effect of the structural transition on the shape of the hysteresis loops. The orthorhombic magnetocrystalline anisotropy of the Pnma phase has been primarily deemed responsible for the high coercivity and remanence of the Zr4+ modified samples. The effect of the grain size and Fe-O-Fe bond angle on the magnetic properties of the samples has also been discussed. Ferroelectricity was found to be absent in Zr-substituted samples because of their non-polar structure. However, the leakage current was reduced by up to two orders of magnitude compared to Bi0.8La0.2FeO3 upon addition of Zr4+. Dielectric measurements conformed to the ferroelectric and leakage current characteristics, and Zr4+ substitution was again found to be beneficial.
Measurement of the electro-optic coefficient during the photoelectric-field assisted poling using a Mach-Zehnder interferometer
Authors: Shimizu Flávio M. , Giacometti José A.
Published: December 2016

This work describes the experimental apparatus based on the Mach-Zehnder interferometer for measuring the electro-optic coefficient during and after the photo-assisted poling process using a continuous light excitation. We also show that the poling can be performed at cryogenic temperatures. The setup is based on the superposition of a Mach-Zehnder AC modulation voltage on the DC bias voltage required to promote the chromophore orientation during light excitation. The effect of the reversible polarization due to the DC bias voltage applied to the polymer film is considered to calculate the electro-optic coefficient during the photo-assisted poling process. The usefulness of our setup is demonstrated with three polymer films, with different electro-optic activities: guest-host, copolymer, and homopolymer, all based on methyl methacrylate monomers and containing disperse red-1 chromophores.
The kite integral to all orders in terms of elliptic polylogarithms
Authors: Adams Luise , Bogner Christian , Schweitzer Armin , Weinzierl Stefan
Published: December 2016

We show that the Laurent series of the two-loop kite integral in D = 4 − 2ε space-time dimensions can be expressed in each order of the series expansion in terms of elliptic generalisations of (multiple) polylogarithms. Using differential equations, we present an iterative method to compute any desired order. As an example, we give the first three orders explicitly.
Investigating the electron density of multi-MeV X-ray-induced air plasmas at low pressures based on electromagnetic resonant cavity analysis
Authors: Ribière M. , d'Almeida T. , Cessenat O. , Maulois M. , Pouzalgues R. , Crabos B. , Delbos C. , Garrigues A. , Azaïs B.
Published: December 2016

We investigate air plasmas generated by multi-MeV pulsed X-rays at pressures ranging from 10−5 to 10−1 mbar. The experimental approach used for these studies is based on measurements of resonant frequencies damping and shift for different electromagnetic modes within a cylindrical cavity. Time-integrated electron densities in X-ray-induced air plasmas are inferred from the damping rate of the measured magnetic fields and their corresponding frequency shifts. In the present study, electron densities ranging from 108 to 109 cm−3 at pressures ranging from 10−3 to 10−1 mbar have been measured. Experimental results were confronted to 3D Maxwell-Vlasov Particle-In-Cell simulations incorporating a radiation-induced electric conductivity model. The method used in this work enables determining microscopic and macroscopic physical quantities within low pressure air plasmas generated by pulsed X-ray.
Condensed phase electron transfer beyond the Condon approximation
Authors: Mavros Michael G. , Hait Diptarka , Van Voorhis Troy
Published: December 2016

Condensed phase electron transfer problems are often simplified by making the Condon approximation: the approximation that the coupling connecting two charge-transfer diabatic states is a constant. Unfortunately, the Condon approximation does not predict the existence of conical intersections, which are ubiquitous in both gas-phase and condensed-phase photochemical dynamics. In this paper, we develop a formalism to treat condensed-phase dynamics beyond the Condon approximation. We show that even for an extremely simple test system, hexaaquairon(ii)/hexaaquairon(iii) self-exchange in water, the electronic coupling is expected to fluctuate rapidly and non-Condon effects must be considered to obtain quantitatively accurate ultrafast nonequilibrium dynamics. As diabatic couplings are expected to fluctuate substantially in many condensed-phase electron transfer systems, non-Condon effects may be essential to quantitatively capture accurate short-time dynamics.
Interaction of solitons for obliquely propagating magnetoacoustic waves in stellar atmosphere
Authors: Jahangir R. , Masood W. , Siddiq M. , Batool Nazia
Published: December 2016

We study here the nonlinear oblique propagation of magnetoacoustic waves in dense plasmas with degenerate electrons by deriving Kadomtsev-Petviashvili (KP) equation for small but finite amplitude perturbations. The two soliton interaction has been studied by finding the solution of the KP equation using the Hirota bilinear formalism. For illustrative purposes, we have used the plasma parameters typically found in white dwarf stars for both the fast and slow modes of magnetoacoustic waves. It has been observed that the soliton interaction in the fast and slow modes is strongly influenced by the predominant and weak dispersive coefficients of the KP equation. The single soliton behavior has also been explained for the fast and slow magnetoacoustic modes.
A technique to control cross-field diffusion of plasma across a transverse magnetic field
Authors: Hazarika P. , Chakraborty M. , Das B. K. , Bandyopadhyay M.
Published: December 2016

A study to control charged particle transport across a transverse magnetic field (TMF), popularly known as the magnetic filter in a negative ion source, has been carried out in a double plasma device. In the experimental setup, the TMF placed between the two magnetic cages divides the whole plasma chamber into two distinct regions, viz., the source and the target on the basis of the plasma production and the corresponding electron temperature. The plasma produced in the source region by the filament discharge method diffuses into the target region through the TMF. Data are acquired by the Langmuir probe and are compared in different source configurations, in terms of external biasing applied to metallic plates inserted in the TMF plane but in the orthogonal direction. The effect of the direction of current between the two plates in either polarity of bias in the presence of TMF on the plasma parameters and the cross-field transport of charge particles are discussed.
The characteristic of magnetized plasma sheath with nanometer-sized dust grains in fusion devices
Authors: Zhao Xiaoyun , Ou Jing , Xiang Nong , Li Dehui , Lin Binbin
Published: December 2016

It is well known that dust grains may affect the sheath structure when dust grains are dense. Typical fluid theory of a dusty plasma sheath assumes that the charging relaxation time of dust grains is much smaller than the time of dust grains across the sheath and the orbit motion limited theory is used to calculate the dust charge. Under these conditions, it is shown that dust charge in the sheath and the sheath parameters associated with dust charge fluctuate within a certain range. However, for fusion plasma, dust grains with large velocity and small radius can often be observed in the edge region of fusion devices. In this case, charge relaxation time may be much longer than the transit time moving from the sheath edge to the wall and then the dust charge can be considered constant. In this paper, one-dimensional multifluid model is developed to study a sheath of dusty plasma containing nanometer-sized dust grains with constant charge based on their long charging relaxation time and the short time across the sheath. It is found that the sheath parameters show monotonic variations and differ from the oscillation variations obtained from the sheath model which the charging relaxation time of dust grains is much smaller than the time across the sheath. In addition, the effects of dust grain density at the sheath edge, dust radius, and ion Mach number on sheath parameters are studied.
The influence of Cu, Al, or Fe on the insulating capacity of CF3I
Authors: Xiao Song , Cressault Yann , Zhang Xiaoxing , Teulet Philippe
Published: December 2016

SF6 is widely used in electrical equipment as an insulating medium. However, SF6 is a serious greenhouse gas. CF3I is considered as one of its potential alternatives. This study verifies whether free metal particle (Cu, Al, or Fe) defects adversely affect CF3I insulation and investigates the incidence from different types and numbers of metal particles. This study is also devoted to calculating specific heat at constant pressure and electrical conductivity of CF3I–metal mixtures. The calculation results prove that with the increase of metal ions, temperature rises faster in the CF3I–Cu plasma or in the CF3I–Fe plasma than in the CF3I plasma without metal absorbing the same energy. The fast development of ionization can promote the increase of free electrons and the rise of electric conductivity. On the basis of the experiments and theoretical analysis, the influence of Cu and Al on the insulating capacity of CF3I is greater than that of Fe.
Multiple stationary filamentary states in a planar dc-driven gas discharge-semiconductor system
Authors: Rafatov Ismail
Published: December 2016

Formation of stationary current filaments is studied in a planar layered structure of gas discharge coupled to a high-Ohmic semiconductor and driven by a stationary voltage (the gas discharge-semiconductor system, GDSS). The simulations are carried out in 2D. The model is based on the diffusion-drift theory of gas discharges. Multiple steady-state solutions in GDSS are found for the first time. The computed discharge parameters are found to be in reasonable agreement with the experiment. Results support the evidence that the thermal mechanism is responsible for the instability in GDSS, under considered conditions. This is also supported by the linear stability analysis of the homogeneous stationary state: with heating of the gas excluded, the instability does not form a spatial structure, it is homogeneous and purely growing without oscillations. Including the gas heating into the model changes the dispersion relation drastically.
Modeling of reduced effective secondary electron emission yield from a velvet surface
Authors: Swanson Charles , Kaganovich Igor D.
Published: December 2016

Complex structures on a material surface can significantly reduce total secondary electron emission from that surface. A velvet is a surface that consists of an array of vertically standing whiskers. The reduction occurs due to the capture of low-energy, true secondary electrons emitted at the bottom of the structure and on the sides of the velvet whiskers. We performed numerical simulations and developed an approximate analytical model that calculates the net secondary electron emission yield from a velvet surface as a function of the velvet whisker length and packing density, and the angle of incidence of primary electrons. We found that to suppress secondary electrons, the following condition on dimensionless parameters must be met: (π/2)DA tan θ≫1, where θ is the angle of incidence of the primary electron from the normal, D is the fraction of surface area taken up by the velvet whisker bases, and A is the aspect ratio, A ≡ h/r, the ratio of height to radius of the velvet whiskers. We find that velvets available today can reduce the secondary electron yield by 90% from the value of a flat surface. The values of optimal velvet whisker packing density that maximally suppresses the secondary electron emission yield are determined as a function of velvet aspect ratio and the electron angle of incidence.
Controlling energy transfer time between two coupled magnetic vortex-state disks
Authors: Vigo-Cotrina H. , Guimarães A. P.
Published: December 2016

The influence of the in-plane uniaxial anisotropy (IPUA) in the mutual energy transfer time (τ) between two identical coupled nanodisks was studied. Using an analytical dipolar model, we obtained the interactions between the disks along x and y directions (the coupling integrals) as a function of the uniaxial anisotropy constant (K σ) and the distance. We find that the IPUA increases the interaction between the disks allowing shorter energy transfer times. For our range of K σ values, we get a drop in the values of τ of up to about 70%. From the Lagrangian of the system, we obtained the equations of motion and the coupling frequencies of the dynamic system as a function of distance and K σ. The coupling frequencies were also obtained from micromagnetic simulations. Our results of the simulations are in agreement with the analytical results.
Unipolar resistive switching characteristics and scaling behaviors in La2Mo2O9 thin films for nonvolatile memory applications
Authors: Hu L. , Lin G. T. , Luo X. , Wei R. H. , Zhu X. B. , Song W. H. , Dai J. M. , Sun Y. P.
Published: December 2016

La2Mo2O9 (LMO) thin films have been deposited on Pt/Ti/SiO2/Si substrates by pulsed laser deposition and the resistive switching (RS) characteristics of the Au/LMO/Pt devices has been investigated. The Au/LMO/Pt devices show excellent unipolar RS characteristics with high resistance ratio between high resistance state and low resistance state (LRS), good endurance, and retention performances. The results of temperature dependence of resistance and x-ray photoelectron spectroscopy suggest that the observed RS characteristics can be explained by the formation and rupture of conducting filaments composed of oxygen vacancies. Furthermore, the plot of the reset current (IR) as a function of the third harmonic coefficient (B0) caused by Joule heating during the reset process shows scaling behavior with a power law of IR∝B0−δ. The IR and reset power (PR) can also be scaled to the resistance in LRS (R0), i.e., IR(PR)∝R0−α(β). The observed scaling behaviors indicate the importance of the Joule heating for the RS characteristics of Au/LMO/Pt devices. These results demonstrate the potential application of LMO thin film in a nonvolatile memory device.
Control surface wettability with nanoparticles from phase-change materials
Authors: ten Brink G. H. , van het Hof P. J. , Chen B. , Sedighi M. , Kooi B. J. , Palasantzas G.
Published: December 2016

The wetting state of surfaces can be controlled physically from the highly hydrophobic to hydrophilic states using the amorphous-to-crystalline phase transition of Ge2Sb2Te5 (GST) nanoparticles as surfactant. Indeed, contact angle measurements show that by increasing the surface coverage of the amorphous nanoparticles the contact angle increases to high values ∼140°, close to the superhydrophobic limit. However, for crystallized nanoparticle assemblies after thermal annealing, the contact angle decreases down to ∼40° (significantly lower than that of the bare substrate) leading to an increased hydrophilicity. Moreover, the wettability changes are also manifested on the capillary adhesion forces by being stronger for the crystallized GST state.
Transport properties of chemically synthesized MoS2 – Dielectric effects and defects scattering
Authors: Mongillo Massimo , Chiappe Daniele , Arutchelvan Goutham , Asselberghs Inge , Perucchini Marta , Manfrini Mauricio , Lin Dennis , Huyghebaert Cedric , Radu Iuliana
Published: December 2016

We report on the electrical characterization of synthetic, large-area MoS2 layers obtained by the sulfurization technique. The effects of dielectric encapsulation and localized defect states on the intrinsic transport properties are explored with the aid of temperature-dependent measurements. We study the effect of dielectric environment by transferring as-grown MoS2 films into different dielectrics such as SiO2, Al2O3, HfO2, and ZrO2 with increasing dielectric permittivity. Electrical data are collected on a statistically-relevant device ensemble and allow to assess device performances on a large scale assembly. Our devices show relative in-sensitiveness of mobility with respect to dielectric encapsulation. We conclude that the device behavior is strongly affected by several scattering mechanisms of different origin that can completely mask any effect related to dielectric mismatch. At low temperatures, conductivity of the devices is thermally activated, a clear footprint of the existence of a mobility edge separating extended states in the conduction band from impurity states in the band-gap.
Lattice-matched Cu2ZnSnS4/CeO2 solar cell with open circuit voltage boost
Authors: Crovetto Andrea , Yan Chang , Iandolo Beniamino , Zhou Fangzhou , Stride John , Schou Jørgen , Hao Xiaojing , Hansen Ole
Published: December 2016

We report a reproducible enhancement of the open circuit voltage in Cu2ZnSnS4 solar cells by introduction of a very thin CeO2 interlayer between the Cu2ZnSnS4 absorber and the conventional CdS buffer. CeO2, a non-toxic earth-abundant compound, has a nearly optimal band alignment with Cu2ZnSnS4 and the two materials are lattice-matched within 0.4%. This makes it possible to achieve an epitaxial interface when growing CeO2 by chemical bath deposition at temperatures as low as 50 °C. The open circuit voltage improvement is then attributed to a decrease in the interface recombination rate through formation of a high-quality heterointerface.
Interplay between quantum well width and interface roughness for electron transport mobility in GaAs quantum wells
Authors: Kamburov D. , Baldwin K. W. , West K. W. , Shayegan M. , Pfeiffer L. N.
Published: December 2016

We report transport mobility measurements for clean, two-dimensional (2D) electron systems confined to GaAs quantum wells (QWs), grown via molecular beam epitaxy, in two families of structures, a standard, symmetrically doped GaAs set of QWs with Al0.32Ga0.68As barriers and one with additional AlAs cladding surrounding the QWs. Our results indicate that the mobility in narrow QWs with no cladding is consistent with existing theoretical calculations where interface roughness effects are softened by the penetration of the electron wave function into the adjacent low barriers. In contrast, data from AlAs-clad wells show a number of samples where the 2D electron mobility is severely limited by interface roughness. These measurements across three orders of magnitude in mobility provide a road map of reachable mobilities in the growth of GaAs structures of different electron densities, well widths, and barrier heights.
Nano-gap between a gold tip and nanorod for polarization dependent surface enhanced Raman scattering
Authors: Cao Zhengmin , He Yingbo , Cheng Yuqing , Zhao Jingyi , Li Guantao , Gong Qihuang , Lu Guowei
Published: December 2016

We demonstrate experimentally that a nano-gap could be constructed by using a scanning probe microscope to allow a gold tip to approach a gold nanorod immobilized on a glass coverslip. The nano-gap can enhance Raman scattering of graphene sandwiched between the tip and the nanorod. The Raman intensity was strongly dependent on the incident light polarization. Here, linear, radial, azimuthal, and intermediate states between radial and azimuthal polarization were investigated and compared in detail. The maximum surface-enhanced Raman scattering effect of the nano-gap occurred for the intermediate states between the radial and azimuthal polarized light.
Direct observation of the M2 phase with its Mott transition in a VO2 film
Authors: Kim Hoon , Slusar Tetiana V. , Wulferding Dirk , Yang Ilkyu , Cho Jin-Cheol , Lee Minkyung , Choi Hee Cheul , Jeong Yoon Hee , Kim Hyun-Tak , Kim Jeehoon
Published: December 2016

In VO2, the explicit origin of the insulator-to-metal transition is still disputable between Peierls and Mott insulators. Along with the controversy, its second monoclinic (M2) phase has received considerable attention due to the presence of electron correlation in undimerized vanadium ions. However, the origin of the M2 phase is still obscure. Here, we study a granular VO2 film using conductive atomic force microscopy and Raman scattering. Upon the structural transition from monoclinic to rutile, we observe directly an intermediate state showing the coexistence of monoclinic M1 and M2 phases. The conductivity near the grain boundary in this regime is six times larger than that of the grain core, producing a donut-like landscape. Our results reveal an intra-grain percolation process, indicating that VO2 with the M2 phase is a Mott insulator.
Evaluation of a pilot school‐based physical activity challenge for primary students
Authors: Passmore E. , Donato‐Hunt C. , Maher L. , Havrlant R. , Hennessey K. , Milat A. , Farrell L.
Published: December 2016

Issue addressed

Physical inactivity and sedentary behaviour among children are growing public health concerns. The Culture Health Communities Activity Challenge (hereafter known as the Challenge) is a school‐based pedometer program in which classes compete to achieve the highest class average daily steps in an 8‐week period. The Challenge aims to encourage physical activity in primary school students, with a focus on engaging Aboriginal students. The program was piloted in 15 classes in New South Wales in 2014.

Methods

The evaluation aimed to explore students’ and teachers’ experiences of the Challenge, and assess its impact on the students’ physical activity levels. Data sources were a pre‐ and post‐intervention survey of students’ physical activity levels and sedentary time (n = 209), qualitative interviews with teachers (n = 11) and discussions with 10 classes.

Results

Fifteen Year 5 and 6 classes comprising 318 students participated. Fifty percent of participants were girls, the average age was 11 years and the majority (57%) were Aboriginal students. Participation in the Challenge was associated with a slight but statistically significant increase in students’ physical activity levels (P < 0.05), and a significant decrease in weekend screen time (P < 0.05). However, when stratified by Aboriginality these changes were not statistically significant for Aboriginal students. Qualitative feedback from teachers and students indicated high levels of engagement and satisfaction with the Challenge. Teachers and students reported positive impacts, including increased motivation to be physically active, and improved student attendance and engagement in class activities and teamwork.

Conclusions

Participation in the Challenge was associated with increased physical activity and decreased screen time for some students. Students and teachers also reported a range of positive social and educational outcomes.

So what?

The findings highlight the importance of primary schools as a setting for health promotion activities, and demonstrate that school‐based physical activity programs can be engaging and appropriate for classes with high proportions of Aboriginal students.
Range extensions in anemonefishes and host sea anemones in eastern Australia: potential constraints to tropicalisation
Authors: Malcolm Hamish , Scott Anna
Published: December 2016

Species distributions at range edges show complex shifts with climate change. The present study examined anemonefish and host sea anemone abundance at their southern distribution limits on the eastern coast of Australia, to identify factors influencing the geographic responses of the symbiosis. Roaming surveys (30min) were conducted at 21 sites (~30.01–30.95°S) on rocky reefs in a tropical–temperate transition zone. Two species of host anemones (Entacmaea quadricolor and Heteractis crispa) and anemonefishes (Amphiprion akindynos and A. latezonatus) were found, along with Dascyllus trimaculatus. Nearly all anemones and anemonefishes (>99.5%) were associated with vegetated islands and rocky islets, and abundance was influenced by seawater temperature. Greater numbers of H. crispa and A. akindynos than E. quadricolor and A. latezonatus were found; however, most A. akindynos were juveniles. H. crispa provided nursery habitat for both fishes, whereas adult fishes utilised only E. quadricolor. A southern range extension was found for E. quadricolor, and overwintering of A. latezonatus had extended poleward since the mid-1990s. The paucity of islands and rocky islets south of our surveys, and host-usage patterns, could constrain future range extensions. These findings showed climate-driven latitudinal shifts are complex and are likely to be variably constrained for different species.
Emergent structures and dynamics of cell colonies by contact inhibition of locomotion
Authors: Smeets Bart , Alert Ricard , Pešek Jiří , Pagonabarraga Ignacio , Ramon Herman , Vincent Romaric
Published: December 2016

Significance

The regular distribution of mesenchymal cells, the formation of epithelial monolayers, or their collapse into spheroidal tumors illustrates the broad range of possible organizations of cells in tissues. Unveiling a physical picture of their emergence and dynamics is of critical importance to understand tissue morphogenesis or cancer progression. Although the role of cell–substrate and cell–cell adhesion in the organization of cell colonies has been widely studied, the impact of the cell-type–specific contact inhibition of locomotion (CIL) remains unclear. Here, we include this interaction in simulations of active particles and find a number of structures and collective dynamics that recapitulate existing tissue phenotypes. We give analytical predictions for the epithelial–mesenchymal transition and the formation of 3D aggregates as a function of cell–cell adhesion and CIL strengths. Thus, our findings shed light on the physical mechanisms underlying multicellular organization.
Receptor kinase complex transmits RALF peptide signal to inhibit root growth in
Arabidopsis
Authors: Du Changqing , Li Xiushan , Chen Jia , Chen Weijun , Li Bin , Li Chiyu , Wang Long , Li Jianglin , Zhao Xiaoying , Lin Jianzhong , Liu Xuanming , Luan Sheng , Yu Feng
Published: December 2016

Significance

Receptor-like kinase FERONIA (FER) is a versatile regulator of cell growth under both normal and stress environments. FER binds its peptide ligand, rapid alkalinization factor 1 (RALF1), and triggers downstream events to inhibit cell growth in primary roots. However, the mechanism of RALF1 reception by FER is still largely unknown. In this study, we identified a receptor-like cytoplasmic kinase (RPM1-induced protein kinase, RIPK) that directly interacts with and is phosphorylated by FER in a RALF1 peptide-dependent manner. The defects of
fer-4
mutant in RALF1 response and root hair development are mimicked by
ripk
loss-of-function but partially compensated by RIPK overexpression. These and other data suggest that formation of the FER–RIPK complex serves as a crucial step in the RALF1 signaling pathway.
Biconcave shape of human red-blood-cell ghosts relies on density differences between the rim and dimple of the ghost's plasma membrane
Authors: Hoffman Joseph F.
Published: December 2016

Significance

The shape of the human red blood cell (RBC) is known to be a biconcave disc. The experiments in this paper identify some of the underlying determinates. RBC ghosts were made such that they were spheres in hypo-osmotic solutions and biconcave discs in iso-osmotic solutions. The spherical ghosts were centrifuged onto coverslips. When these spheres became biconcave discs by flushing with an iso-osmotic solution, the ghosts laid
flat
on the coverslip. This indicates that, during centrifugation, the spherical ghosts were oriented by a dense band in their equatorial planes. This unique orientation appears to be the first evidence that differences in the densities between the rim and the dimple regions of RBCs and their ghosts underlie their biconcave shape.
State estimation and prediction using clustered particle filters
Authors: Lee Yoonsang , Majda Andrew J.
Published: December 2016

Significance

Particle filtering is an essential tool for the estimation and prediction of complex systems including non-Gaussian features. A class of particle filters, clustered particle filters, is introduced for high-dimensional dynamical systems such as geophysical systems. The proposed method uses relatively few particles compared with the standard particle filter and captures the non-Gaussian features of the true signal, which are typical in complex nonlinear systems. The method is also robust for the difficult regime of high-quality sparse and infrequent observations and does not show any filter divergence in our tests. In the clustered particle filter, coarse-grained localization is implemented through the clustering of state variables and particles are adjusted to stabilize the filter.
Chromosome instability drives phenotypic switching to metastasis
Authors: Gao ChongFeng , Su Yanli , Koeman Julie , Haak Elizabeth , Dykema Karl , Essenberg Curt , Hudson Eric , Petillo David , Khoo Sok Kean , Vande Woude George F.
Published: December 2016

Significance

Chromosome instability and its resulting karyotypic heterogeneity make up one of the most striking characteristics of human cancers. Yet whether chromosome loss or gain drives tumor progression to metastasis remains unknown. Here we show that clonal populations of epithelial cells spontaneously generate mesenchymal variants. These variants have potential for reverting to an epithelial phenotype. Importantly, we show that the successive phenotypic variants selectively eliminate or acquire chromosome segments that harbor genes encoding intercellular junctional proteins and their regulators. Thus, tumor metastasis can be a clonal process driven by chromosome instability.
Reducing Size Variation in Hybrid Catfish Culture through Graded Partial Harvest
Authors: Mischke Charles C , Brown Travis W , Tucker Craig S , Torrans E Les
Published: December 2016

Hybrid catfish (female Channel Catfish Ictalurus punctatus × male Blue Catfish I. furcatus) have quickly become a major contributor to ictalurid catfish aquaculture in the United States. Hybrid catfish have unique production characteristics compared with Channel Catfish, and rapid adoption of the hybrid by fish farmers has outpaced research on appropriate management practices. This study was conducted to determine the effect of midsummer partial harvest of faster-growing fish on production characteristics in ponds with hybrid catfish in single-batch culture. Twelve 1.0-acre ponds were stocked with 10,000 year-class 1 hybrid catfish (~0.12 lb/fish) in mid-March 2015. In August 2015, six random ponds were partially harvested to remove fish larger than ~1.25 lb using an in-pond, flexible-panel, grading sock. In October 2015, all ponds were completely harvested. Partial harvest of faster-growing fish removed ~26% of fish from ponds in August. Removal of faster-growing fish resulted in 0.9% of the total crop considered “out-of-size” (>4 lb/fish) and subject to discounts, compared with 2.1% of the fish from the control ponds. However, reduction of fish numbers by midsummer partial harvest reduced overall production by an average of 16% in the partial-harvest treatment compared with control ponds. Overall, partial harvest of faster-growing fish in midsummer reduced the overall biomass of discounted, out-of-size fish. Higher production in control ponds resulted in greater net revenue.
Analysis of Physical Properties and Mineralogical of Pyrolysis Tires Rubber Ash Compared Natural Sand in Concrete material
Authors: Senin Mohamad Syamir , Shahidan Shahiron , Leman Alif Syazani , Hannan Nurul Izzati Raihan Ramzi
Published: December 2016

Waste tires pose significant health and environmental concerns if not recycled or discarded properly. At the same time, natural sand is becoming scarcer and costlier due to its non-availability. Waste tires as fine aggregate can be an economical and sustainable alternative to the natural sand. Recent years, the interest on recycling waste tires into civil engineering applications by the researchers has increased. In this research, the chemical and physical properties of the tires rubber ash and the natural sand have been analysed. The densities of the rubber ash are lower than the natural sand. Rubber ash had finer particle size compared to the natural sand. Almost all chemical in the natural sand had in rubber ash with the additional sulphur trioxide and zinc oxide in the rubber ash, made the rubber ash better than natural sand. Rubber ash seems to be a suitable material to use in concrete as sand replacement.
ProTEK PSB as Biotechnology Photosensitive Protection Mask on 3C-SiC-on-Si in MEMS Sensor
Authors: Marsi N , Majlis B Y , Mohd-Yasin F , Hamzah A A , Rus A Z Mohd
Published: December 2016

This project presents the fabrication of MEMS employing a cubic silicon carbide (3C- SiC) on silicon wafer using newly developed ProTEK PSB as biotechnology photosensitive protection mask. This new biotechnology can reduce the number of processes and simplify the process flow with minimal impact on overall undercut performance. The 680 pm thick wafer is back-etched, leaving the 3C-SiC thin film with a thickness of 1.0 μm as the flexible diaphragm to detect pressure. The effect of the new coating of ProTEK PSB on different KOH solvents were investigated depending on various factors such as development time, final cure temperature and the thickness of the ProTEK PSB deposited layer. It is found that 6.174 μm thickness of ProTEK PSB offers some possibility of reducing the processing time compared to silicon nitride etch masks in KOH (55%wt, 80°C). The new ProTEK PSB biotechnology photosensitive protection mask indicates good stability and sustains its performance in different treatments under KOH and IPA for 8 hours. This work also revealed that the fabrication of MEMS sensors using the new biotechnology photosensitive protection mask provides a simple assembly approach and reduces manufacturing costs. The MEMS sensor can operate up to 500 °C as indicated under the sensitivity of 0.826 pF/MPa with nonlinearity and hysteresis of 0.61% and 3.13%, respectively.