bluuebunny/crossref_metadata_2025 huggingface dataset:
Interface modulated currents in periodically proton exchanged Mg doped lithium niobate
Authors: Neumayer Sabine M. , Manzo Michele , Kholkin Andrei L. , Gallo Katia , Rodriguez Brian J.
Published: March 2016

Conductivity in Mg doped lithium niobate (Mg:LN) plays a key role in the reduction of photorefraction and is therefore widely exploited in optical devices. However, charge transport through Mg:LN and across interfaces such as electrodes also yields potential electronic applications in devices with switchable conductivity states. Furthermore, the introduction of proton exchanged (PE) phases in Mg:LN enhances ionic conductivity, thus providing tailorability of conduction mechanisms and functionality dependent on sample composition. To facilitate the construction and design of such multifunctional electronic devices based on periodically PE Mg:LN or similar ferroelectric semiconductors, fundamental understanding of charge transport in these materials, as well as the impact of internal and external interfaces, is essential. In order to gain insight into polarization and interface dependent conductivity due to band bending, UV illumination, and chemical reactivity, wedge shaped samples consisting of polar oriented Mg:LN and PE phases were investigated using conductive atomic force microscopy. In Mg:LN, three conductivity states (on/off/transient) were observed under UV illumination, controllable by the polarity of the sample and the externally applied electric field. Measurements of currents originating from electrochemical reactions at the metal electrode–PE phase interfaces demonstrate a memresistive and rectifying capability of the PE phase. Furthermore, internal interfaces such as domain walls and Mg:LN–PE phase boundaries were found to play a major role in the accumulation of charge carriers due to polarization gradients, which can lead to increased currents. The insight gained from these findings yield the potential for multifunctional applications such as switchable UV sensitive micro- and nanoelectronic devices and bistable memristors.
Influence of network topology on the swelling of polyelectrolyte nanogels
Authors: Rizzi L. G. , Levin Y.
Published: March 2016

It is well-known that the swelling behavior of ionic nanogels depends on their cross-link density; however, it is unclear how different topologies should affect the response of the polyelectrolyte network. Here we perform Monte Carlo simulations to obtain the equilibrium properties of ionic nanogels as a function of salt concentration Cs and the fraction f of ionizable groups in a polyelectrolyte network formed by cross-links of functionality z. Our results indicate that the network with cross-links of low connectivity result in nanogel particles with higher swelling ratios. We also confirm a de-swelling effect of salt on nanogel particles.
Efficient generation of sum-of-products representations of high-dimensional potential energy surfaces based on multimode expansions
Authors: Ziegler Benjamin , Rauhut Guntram
Published: March 2016

The transformation of multi-dimensional potential energy surfaces (PESs) from a grid-based multimode representation to an analytical one is a standard procedure in quantum chemical programs. Within the framework of linear least squares fitting, a simple and highly efficient algorithm is presented, which relies on a direct product representation of the PES and a repeated use of Kronecker products. It shows the same scalings in computational cost and memory requirements as the potfit approach. In comparison to customary linear least squares fitting algorithms, this corresponds to a speed-up and memory saving by several orders of magnitude. Different fitting bases are tested, namely, polynomials, B-splines, and distributed Gaussians. Benchmark calculations are provided for the PESs of a set of small molecules.
The thermodynamics and kinetics of a nucleotide base pair
Authors: Wang Yujie , Gong Sha , Wang Zhen , Zhang Wenbing
Published: March 2016

The thermodynamic and kinetic parameters of an RNA base pair were obtained through a long-time molecular dynamics simulation of the opening-closing switch process of the base pair near its melting temperature. The thermodynamic parameters were in good agreement with the nearest-neighbor model. The opening rates showed strong temperature dependence, however, the closing rates showed only weak temperature dependence. The transition path time was weakly temperature dependent and was insensitive to the energy barrier. The diffusion constant exhibited super-Arrhenius behavior. The free energy barrier of breaking a single base stack results from the enthalpy increase, ΔH, caused by the disruption of hydrogen bonding and base-stacking interactions. The free energy barrier of base pair closing comes from the unfavorable entropy loss, ΔS, caused by the restriction of torsional angles. These results suggest that a one-dimensional free energy surface is sufficient to accurately describe the dynamics of base pair opening and closing, and the dynamics are Brownian.
Effect of water on structure and dynamics of [BMIM][PF6] ionic liquid: An all-atom molecular dynamics simulation investigation
Authors: Sharma Anirban , Ghorai Pradip Kr.
Published: March 2016

Composition dependent structural and dynamical properties of aqueous hydrophobic 1-butyl-3-methylimidazolium hexafluorophosphate ([BMIM][PF6]) ionic liquid (IL) have been investigated by using all-atom molecular dynamics simulation. We observe that addition of water does not increase significant number of dissociated ions in the solution over the pure state. As a consequence, self-diffusion coefficient of the cation and anion is comparable to each other at all water concentration similar to that is observed for the pure state. Voronoi polyhedra analysis exhibits strong dependence on the local environment of IL concentration. Void and neck distributions in Voronoi tessellation are approximately Gaussian for pure IL but upon subsequent addition of water, we observe deviation from the Gaussian behaviour with an asymmetric broadening with long tail of exponential decay at large void radius, particularly at higher water concentrations. The increase in void space and neck size at higher water concentration facilitates ionic motion, thus, decreasing dynamical heterogeneity and IL reorientation time and increases self-diffusion coefficient significantly.
Luminescence properties of Ce3+ and Tb3+ co-doped SiOxNy thin films: Prospects for color tunability in silicon-based hosts
Authors: Ramírez J. M. , Ruiz-Caridad A. , Wojcik J. , Gutierrez A. M. , Estradé S. , Peiró F. , Sanchís P. , Mascher P. , Garrido B.
Published: March 2016

In this work, the role of the nitrogen content, the annealing temperature, and the sample morphology on the luminescence properties of Ce3+ and Tb3+ co-doped SiOxNy thin films has been investigated. An increasing nitrogen atomic percentage has been incorporated in the host matrix by gradually replacing oxygen with nitrogen during fabrication while maintaining the Si content unaltered, obtaining a sequential variation in the film composition from nearly stoichiometric SiO2 to SiOxNy. The study of rare earth doped single layers has allowed us to identify the parameters that yield an optimum optical performance from Ce3+ and Tb3+ ions. Ce3+ ions proved to be highly sensitive to the annealing temperature and the nitrogen content, showing strong PL emission for relatively low nitrogen contents (from 0 to 20%) and moderate annealing temperatures (800–1000 °C) or under high temperature annealing (1180 °C). Tb3+ ions, on the other hand, displayed a mild dependence on those film parameters. Rare earth co-doping has also been investigated by comparing the luminescence properties of three different approaches: (i) a Ce3+ and Tb3+ co-doped SiOxNy single layer, (ii) a bilayer composed of two SiOxNy single layers doped with either Ce3+ or Tb3+ ions, and (iii) a multilayer composed of a series of either Tb3+ or Ce3+-doped SiOxNy thin films with interleaved SiO2 spacers. Bright green emission and efficient energy transfer from either Ce3+ ions or Ce silicates to Tb3+ ions has been observed in the co-doped single layer as a consequence of the strong ion-ion interaction. On the other hand, independent luminescence from Ce3+ and Tb3+ ions has been observed in the Ce3+ and Tb3+ co-doped bilayer and multilayer, providing a good scenario to develop light emitting devices with wide color tunability by varying the number of deposited films that contain each rare earth dopant. Moreover, the optoelectronic properties of Ce3+- and/or Tb3+-doped thin films have been studied by depositing transparent conductive electrodes over selected samples. An electroluminescence signal according to the rare earth transitions is obtained in all cases, validating the excitation of Ce3+ and Tb3+ ions upon electron injection. Also, the main charge transport of injected electrons has been evaluated and correlated with the layer stoichiometry. Finally, a simple reliability test has allowed disclosing the origin of the early breakdown of test devices, attributed to the excessive joule heating at filament currents that occur around a region close to the polarization point.
Quantitative X-ray dark-field and phase tomography using single directional speckle scanning technique
Authors: Wang Hongchang , Kashyap Yogesh , Sawhney Kawal
Published: March 2016

X-ray dark-field contrast tomography can provide important supplementary information inside a sample to the conventional absorption tomography. Recently, the X-ray speckle based technique has been proposed to provide qualitative two-dimensional dark-field imaging with a simple experimental arrangement. In this letter, we deduce a relationship between the second moment of scattering angle distribution and cross-correlation degradation of speckle and establish a quantitative basis of X-ray dark-field tomography using single directional speckle scanning technique. In addition, the phase contrast images can be simultaneously retrieved permitting tomographic reconstruction, which yields enhanced contrast in weakly absorbing materials. Such complementary tomography technique can allow systematic investigation of complex samples containing both soft and hard materials.
Opto-electrochemical spectroscopy of metals in aqueous solutions
Authors: Habib K.
Published: March 2016

In the present investigation, holographic interferometry was utilized for the first time to determine the rate change of the electrical resistance of aluminium samples during the initial stage of anodisation processes in aqueous solution. In fact, because the resistance values in this investigation were obtained by holographic interferometry, electromagnetic method rather than electronic method, the abrupt rate change of the resistance was called electrical resistance–emission spectroscopy. The anodisation process of the aluminium samples was carried out by electrochemical impedance spectroscopy (EIS) in different sulphuric acid concentrations (1.0%–2.5% H2SO4) at room temperature. In the meantime, the real time holographic interferometry was used to determine the difference between the electrical resistance of two subsequent values, dR, as a function of the elapsed time of the EIS experiment for the aluminium samples in 1.0%, 1.5%, 2.0%, and 2.5% H2SO4 solutions. The electrical resistance–emission spectra of the present investigation represent a detailed picture of not only the rate change of the electrical resistance throughout the anodisation processes but also the spectra represent the rate change of the growth of the oxide films on the aluminium samples in different solutions. As a result, a new spectrometer was developed based on the combination of the holographic interferometry and electrochemical impedance spectroscopy for studying in situ the electrochemical behavior of metals in aqueous solutions.
Enhanced microwave-to-terahertz absorption in graphene
Authors: Batrakov K. , Kuzhir P. , Maksimenko S. , Volynets N. , Voronovich S. , Paddubskaya A. , Valusis G. , Kaplas T. , Svirko Yu. , Lambin Ph.
Published: March 2016

Fresnel equations predict that an ultrathin free standing conductive film, thousands times thinner than skin depth, is capable to absorb up to 50% of incident electromagnetic radiations. In the microwave range, the same holds true for a free standing graphene sheet. We demonstrate theoretically and prove experimentally that microwave absorptance of graphene can be enhanced considerably by depositing graphene on a dielectric substrate. On the experimental side, we obtain 80% and 65% absorptance at 30 GHz and 1 THz, respectively. Theory predicts that higher absorptance can be achieved with a suitable choice of the dielectric permittivity and the thickness of the substrate. Absorption can also be maximized by choosing the optimum incidence angle for s-polarized waves in free space or by working in the vicinity of the cut-off frequency of the transverse electric mode in waveguide configuration. The polarization sensitivity of the transmittance and reflectance of graphene layers can be used to tune the polarization state of the transmitted and reflected radiations.
In-plane/out-of-plane disorder influence on the magnetic anisotropy of Fe1−yMnyPt-L1 bulk alloy
Authors: Cuadrado R. , Liu Kai , Klemmer Timothy J. , Chantrell R. W.
Published: March 2016

The random substitution of a non-magnetic species instead of Fe atoms in FePt-L10 bulk alloy will permit to tune the magnetic anisotropy energy of this material. We have performed by means of first principles calculations a study of Fe1−yMnyPt-L10 (y = 0.0, 0.08, 0.12, 0.17, 0.22, and 0.25) bulk alloy for a fixed Pt concentration when the Mn species have ferro-/antiferromagnetic (FM,AFM) alignment at the same(different) atomic plane(s). This substitution will promote several in-plane lattice values for a fixed amount of Mn. Charge hybridization will change compared to the FePt-L10 bulk due to this lattice variation leading to a site resolved magnetic moment modification. We demonstrate that this translates into a total magnetic anisotropy reduction for the AFM phase and an enhancement for the FM alignment. Several geometric configurations were taken into account for a fixed Mn concentration because of different possible Mn positions in the simulation cell.
Experimental and theoretical investigation of temperature-dependent electrical fatigue studies on 1-3 type piezocomposites
Authors: Mohan Y. , Arockiarajan A.
Published: March 2016

1-3 type piezocomposites are very attractive materials for transducers and biomedical application, due to its high electromechanical coupling effects. Reliability study on 1-3 piezocomposites subjected to cyclic loading condition in transducer application is one of the primary concern. Hence, this study focuses on 1-3 piezocomposites for various PZT5A1 fiber volume fraction subjected to electrical fatigue loading up-to 106 cycles and at various elevated temperature. Initially experiments are performed on 1-3 piezocomposites, in order to understand the degradation phenomena due to various range in amplitude of electric fields (unipolar & bipolar), frequency of applied electric field and for various ambient temperature. Performing experiments for high cycle fatigue and for different fiber volume fraction of PZT5A1 is a time consuming process. Hence, a simplified macroscopic uni-axial model based on physical mechanisms of domain switching and continuum damage mechanics has been developed to predict the non-linear fatigue behaviour of 1-3 piezocomposites for temperature dependent electrical fatigue loading conditions. In this model, damage effects namely domain pinning, frozen domains and micro cracks, are considered as a damage variable (ω). Remnant variables and material properties are considered as a function of internal damage variable and the growth of the damage is derived empirically based on the experimental observation to predict the macroscopic changes in the properties. The measured material properties and dielectric hysteresis (electric displacement vs. electric field) as well as butterfly curves (longitudinal strain vs. electric field) are compared with the simulated results. It is observed that variation in amplitude of bipolar electric field and temperature has a strong influence on the response of 1-3 piezocomposites.
Interface electronic properties of co-evaporated MAPbI3 on ZnO(0001): In situ X-ray photoelectron spectroscopy and ultraviolet photoelectron spectroscopy study
Authors: Zhou Xianzhong , Li Xiaoli , Liu Yuan , Huang Feng , Zhong Dingyong
Published: March 2016

In this work, the interface electronic properties of ZnO(0001)/CH3NH3PbI3 were investigated by both X-ray and ultraviolet photoelectron spectroscopy. The CH3NH3PbI3 thin films were grown on single crystalline ZnO(0001) substrate in situ by co-evaporation of PbI2 and CH3NH3I at room temperature with various thickness from 1.5 nm to 190 nm. It was found that the conduction band minimum of ZnO lies 0.3 eV below that of CH3NH3PbI3, while the valence band maximum of ZnO lies 2.1 eV below that of CH3NH3PbI3, implying that the electrons can be effectively transported from CH3NH3PbI3 to ZnO, and the holes can be blocked in the same time. A PbI2 rich layer was initially formed at the interface of ZnO(0001)/CH3NH3PbI3 during the growth. As a consequence, an interface barrier was built up which may prevent the electron transport at the interface.
Optical and acoustic sensing using Fano-like resonances in dual phononic and photonic crystal plate
Authors: Amoudache Samira , Moiseyenko Rayisa , Pennec Yan , Rouhani Bahram Djafari , Khater Antoine , Lucklum Ralf , Tigrine Rachid
Published: March 2016

We perform a theoretical study based on the transmissions of optical and acoustic waves normally impinging to a periodic perforated silicon plate when the embedded medium is a liquid and show the existence of Fano-like resonances in both cases. The signature of the resonances appears as well-defined asymmetric peaks in the phononic and photonic transmission spectra. We show that the origin of the Fano-like resonances is different with respect to the nature of the wave. In photonic, the origin comes from guided modes in the photonic plate while in phononic we show that it comes from the excitation of standing waves confined inside the cavity coming from the deformation of the water/silicon edges of the cylindrical inclusion. We finally use these features for sensing and show ultra-sensitivity to the light and sound velocities for different concentrations of analytes.
Analytical modeling and numerical simulation of the short-wave infrared electron-injection detectors
Authors: Movassaghi Yashar , Fathipour Vala , Fathipour Morteza , Mohseni Hooman
Published: March 2016

This paper describes comprehensive analytical and simulation models for the design and optimization of the electron-injection based detectors. The electron-injection detectors evaluated here operate in the short-wave infrared range and utilize a type-II band alignment in InP/GaAsSb/InGaAs material system. The unique geometry of detectors along with an inherent negative-feedback mechanism in the device allows for achieving high internal avalanche-free amplifications without any excess noise. Physics-based closed-form analytical models are derived for the detector rise time and dark current. Our optical gain model takes into account the drop in the optical gain at high optical power levels. Furthermore, numerical simulation studies of the electrical characteristics of the device show good agreement with our analytical models as well experimental data. Performance comparison between devices with different injector sizes shows that enhancement in the gain and speed is anticipated by reducing the injector size. Sensitivity analysis for the key detector parameters shows the relative importance of each parameter. The results of this study may provide useful information and guidelines for development of future electron-injection based detectors as well as other heterojunction photodetectors.
Elasto-inertial particle focusing under the viscoelastic flow of DNA solution in a square channel
Authors: Kim Bookun , Kim Ju Min
Published: March 2016

Particle focusing is an essential step in a wide range of applications such as cell counting and sorting. Recently, viscoelastic particle focusing, which exploits the spatially non-uniform viscoelastic properties of a polymer solution under Poiseuille flow, has attracted much attention because the particles are focused along the channel centerline without any external force. Lateral particle migration in polymer solutions in square channels has been studied due to its practical importance in lab-on-a-chip applications. However, there are still many questions about how the rheological properties of the medium alter the equilibrium particle positions and about the flow rate ranges for particle focusing. In this study, we investigated lateral particle migration in a viscoelastic flow of DNA solution in a square microchannel. The elastic property is relevant due to the long relaxation time of a DNA molecule, even when the DNA concentration is extremely low. Further, the shear viscosity of the solution is essentially constant irrespective of shear rate. Our current results demonstrate that the particles migrate toward the channel centerline and the four corners of a square channel in the dilute DNA solution when the inertia is negligible (elasticity-dominant flow). As the flow rate increases, the multiple equilibrium particle positions are reduced to a single file along the channel centerline, due to the elasto-inertial particle focusing mechanism. The current results support that elasto-inertial particle focusing mechanism is a universal phenomenon in a viscoelastic fluid with constant shear viscosity (Boger fluid). Also, the effective flow rate ranges for three-dimensional particle focusing in the DNA solution were significantly higher and wider than those for the previous synthetic polymer solution case, which facilitates high throughput analysis of particulate systems. In addition, we demonstrated that the DNA solution can be applied to focus a wide range of particle sizes in a single channel and also align red blood cells without any significant deformation.
Modifications in surface, structural and mechanical properties of brass using laser induced Ni plasma as an ion source
Authors: Ahmad Shahbaz , Bashir Shazia , Rafique M. Shahid , Yousaf Daniel
Published: March 2016

Laser induced Ni plasma has been employed as source of ion implantation for surface, structural and mechanical properties of brass. Excimer laser (248 nm, 20 ns, 120mJ and 30 Hz) was used for the generation of Ni plasma. Thomson parabola technique was employed to estimate the energy of generated ions using CR39 as a detector. In response to stepwise increase in number of laser pulses from 3000 to 12000, the ion dose varies from 60 × 1013 to 84 × 1016 ions/cm2 with constant energy of 138 KeV. SEM analysis reveals the growth of nano/micro sized cavities, pores, pits, voids and cracks for the ion dose ranging from 60 × 1013 to 70 × 1015 ions/cm2. However, at maximum ion dose of 84 × 1016 ions/cm2 the granular morphology is observed. XRD analysis reveals that new phase of CuZnNi (200) is formed in the brass substrate after ion implantation. However, an anomalous trend in peak intensity, crystallite size, dislocation line density and induced stresses is observed in response to the implantation with various doses. The increase in ion dose causes to decrease the Yield Stress (YS), Ultimate Tensile Strength (UTS) and hardness. However, for the maximum ion dose the highest values of these mechanical properties are achieved. The variations in the mechanical properties are correlated with surface and crystallographical changes of ion implanted brass.
One step antibody-mediated isolation and patterning of multiple cell types in microfluidic devices
Authors: Bavli Danny , Ezra Elishai , Kitsberg Daniel , Vosk-Artzi Margarita , Murthy Shashi K. , Nahmias Yaakov
Published: March 2016

Cell-cell interactions play a key role in regeneration, differentiation, and basic tissue function taking place under physiological shear forces. However, current solutions to mimic such interactions by micro-patterning cells within microfluidic devices have low resolution, high fabrication complexity, and are limited to one or two cell types. Here, we present a microfluidic platform capable of laminar patterning of any biotin-labeled peptide using streptavidin-based surface chemistry. The design permits the generation of arbitrary cell patterns from heterogeneous mixtures in microfluidic devices. We demonstrate the robust co-patterning of α-CD24, α-ASGPR-1, and α-Tie2 antibodies for rapid isolation and co-patterning of mixtures of hepatocytes and endothelial cells. In addition to one-step isolation and patterning, our design permits step-wise patterning of multiple cell types and empty spaces to create complex cellular geometries in vitro. In conclusion, we developed a microfluidic device that permits the generation of perfusable tissue-like patterns in microfluidic devices by directly injecting complex cell mixtures such as differentiated stem cells or tissue digests with minimal sample preparation.
Effects of aging time and temperature of Fe-1wt.%Cu on magnetic Barkhausen noise and FORC
Authors: Saleh Muad , Cao Yue , Edwards Danny J. , Ramuhalli Pradeep , Johnson Bradley R. , McCloy John S.
Published: March 2016

Magnetic Barkhausen noise (MBN), hysteresis measurements, first order reversal curves (FORC), Vickers microhardness, and Transmission Electron Microscopy (TEM) analyses were performed on Fe-1wt.%Cu (Fe-Cu) samples isothermally aged at 700°C for 0.5 – 25 hours to obtain samples with different sized Cu precipitates and dislocation structures. Fe-Cu is used to simulate the thermal and irradiation-induced defects in copper-containing nuclear reactor materials such as cooling system pipes and pressure vessel materials. The sample series showed an initial increase followed by a decrease in hardness and coercivity with aging time, which is explained by Cu precipitates formation and growth as observed by TEM measurements. Further, the MBN envelope showed a continuous decrease in its magnitude and the appearance of a second peak with aging. Also, FORC diagrams showed multiple peaks whose intensity and location changed for different aging time. The changes in FORC diagrams are attributed to combined changes of the magnetic behavior due to Cu precipitate characteristics and dislocation structure. A second series of samples aged at 850°C, which is above the solid solution temperature of Fe-Cu, was studied to isolate the effects of dislocations. These samples showed a continuous decrease in MBN amplitude with aging time although the coercivity and hardness did not change significantly. The decrease of MBN amplitude and the appearance of the second MBN envelope peak are attributed to the changes in dislocation density and structure. This study shows that the effect of dislocations on MBN and FORC of Fe-Cu materials can vary significantly and should be considered in interpreting magnetic signatures.
Magnetic ordering in Gd5Ir2Bi and Gd5Ir2Sb
Authors: Ryan D. H. , Mas Nadejda , Rejali Rasa , Miller T. , Gerke Birgit , Heying Birgit , Pöttgen Rainer , Flacau Roxana
Published: March 2016

155Gd Mössbauer spectroscopy and neutron powder diffraction have been used to study magnetic ordering in Gd5Ir2Bi and Gd5Ir2Sb. Despite the hyperfine fields (Bhf) at the two Gd sites differing by more than a factor of two for both compounds, the moments derived from neutron diffraction are essentially equal in Gd5Ir2Bi. This implies an unusual departure from the commonly assumed scaling between BhfGd and μGd. Neutron powder diffraction shows that Gd5Ir2Bi is a c-axis ferromagnet at 3.6 K. We find no evidence for a FM → AF transition.
Size dependent magnetic and electrical properties of Ba-doped nanocrystalline BiFeO3
Authors: Hasan Mehedi , Hakim M. A. , Basith M. A. , Hossain Md. Sarowar , Ahmmad Bashir , Zubair M. A. , Hussain A. , Islam Md. Fakhrul
Published: March 2016

Improvement in magnetic and electrical properties of multiferroic BiFeO3 in conjunction with their dependence on particle size is crucial due to its potential applications in multifunctional miniaturized devices. In this investigation, we report a study on particle size dependent structural, magnetic and electrical properties of sol-gel derived Bi0.9Ba0.1FeO3 nanoparticles of different sizes ranging from ∼ 12 to 49 nm. The substitution of Bi by Ba significantly suppresses oxygen vacancies, reduces leakage current density and Fe2+ state. An improvement in both magnetic and electrical properties is observed for 10 % Ba-doped BiFeO3 nanoparticles compared to its undoped counterpart. The saturation magnetization of Bi0.9Ba0.1FeO3 nanoparticles increase with reducing particle size in contrast with a decreasing trend of ferroelectric polarization. Moreover, a first order metamagnetic transition is noticed for ∼ 49 nm Bi0.9Ba0.1FeO3 nanoparticles which disappeared with decreasing particle size. The observed strong size dependent multiferroic properties are attributed to the complex interaction between vacancy induced crystallographic defects, multiple valence states of Fe, uncompensated surface spins, crystallographic distortion and suppression of spiral spin cycloid of BiFeO3.
Stability of Polymer Interlayer Modified ITO Electrodes for Organic Solar Cells
Authors: Sharma Anirudh , George Zandra , Bennett Trystan , Lewis David A. , Metha Gregory F. , Andersson Gunther G. , Andersson Mats R.
Published: March 2016

Indium-tin-oxide (ITO) electrode surfaces were modified using thin polymeric films of ethoxylated polyethylenimine (PEIE) and poly(3,3′-([(9′,9′-dioctyl-9H,9′H-[2,2′-bifluorene]-9,9-diyl)bis(4,1-phenylene)]bis(oxy))bis(N,N-dimethylpropan-1-amine)) (PFPA-1) to investigate the resultant work function and its stability in ambient atmosphere. Both PEIE and PFPA-1 were found to significantly reduce the ITO work function, as a result of a surface dipole at the ITO–polymer interface. After aging for two weeks in ambient air atmosphere, the N-side groups and OH groups in PEIE-modified ITO were found to realign themselves away from the polymer surface, resulting in an orientation more parallel to the surface normal and thus in an increase in work function from 3.5 to 3.8 eV. The work function of PFPA-1-modified ITO was found to increase from 3.65 to 4.1 eV after two weeks of aging in air due to a complete re-orientation of the polar side chains away from the surface, aligning the dipoles more parallel to the surface normal. In both PEIE and PFPA-1 samples, the hydrophobic aliphatic carbon was found to dominate the polymer surface, after aging.
Re-evaluating sowing time of spring canola (Brassica napus L.) in south-eastern Australia—how early is too early?
Authors: Kirkegaard J. A. , Lilley J. M. , Brill R. D. , Sprague S. J. , Fettell N. A. , Pengilley G. C.
Published: March 2016

Optimising the sowing date of canola (Brassica napus L.) in specific environments is an important determinant of yield worldwide. In eastern Australia, late April to early May has traditionally been considered the optimum sowing window for spring canola, with significant reduction in yield and oil in later sown crops. Recent and projected changes in climate, new vigorous hybrids, and improved fallow management and seeding equipment have stimulated a re-evaluation of early-April sowing to capture physiological advantages of greater biomass production and earlier flowering under contemporary conditions. Early–mid-April sowing generated the highest or equal highest yield and oil content in eight of nine field experiments conducted from 2002 to 2012 in south-eastern Australia. Declines in seed yield (–6.0% to –6.5%), oil content (–0.5% to –1.5%) and water-use efficiency (–3.8% to –5.5%) per week delay in sowing after early April reflected levels reported in previous studies with sowings from late April. Interactions with cultivar phenology were evident at some sites depending on seasonal conditions. There was no consistent difference in performance between hybrid and non-hybrid cultivars at the earliest sowing dates. Despite low temperatures thought to damage early pods at some sites (<−2°C), frost damage did not significantly compromise the yield of the early-sown crops, presumably because of greater impact of heat and water-stress in the later sown crops. A validated APSIM-Canola simulation study using 50 years of weather data at selected sites predicted highest potential yields from early-April sowing. However, the application of a frost-heat sensitivity index to account for impacts of temperature stress during the reproductive phase predicted lower yields and higher yield variability from early-April sowing. The frost–heat-limited yields predicted optimum sowing times of mid-April at southern sites, and late April to early May at the northern sites with lower median yield and higher yield variability in crops sown in early April. The experimental and simulation data are potentially compatible given that the experiments occurred during the decade of the Millennium drought in south-eastern Australia (2002–10), with dry and hot spring conditions favouring earlier sowing. However, the study reveals the need for more accurate and validated prediction of the frost and heat impacts on field-grown canola if simulation models are to provide more accurate prediction of attainable yield as new combinations of cultivar and sowing dates are explored.
Direct and indirect effects of near-future pCO2 levels on zooplankton dynamics
Authors: Meunier Cédric L. , Algueró-Muñiz María , Horn Henriette G. , Lange Julia A. F. , Boersma Maarten
Published: March 2016

Ocean acidification has direct physiological effects on organisms, for example by dissolving the calcium carbonate structures of calcifying species. However, non-calcifiers may also be affected by changes in seawater chemistry. To disentangle the direct and indirect effects of ocean acidification on zooplankton growth, we undertook a study with two model organisms. Specifically, we investigated the individual effects of short-term exposure to high and low seawater pCO2, and different phytoplankton qualities as a result of different CO2 incubations on the growth of a heterotrophic dinoflagellate (Oxyrrhis marina) and a copepod species (Acartia tonsa). It was observed previously that higher CO2 concentrations can decrease phytoplankton food quality in terms of carbon:nutrient ratios. We therefore expected both seawater pCO2 (pH) and phytoplankton quality to result in decreased zooplankton growth. Although we expected lowest growth rates for all zooplankton under high seawater pCO2 and low algal quality, we found that direct pH effects on consumers seem to be of lesser importance than the associated decrease in algal quality. The decrease in the quality of primary producers under high pCO2 conditions negatively affected zooplankton growth, which may lead to lower availability of food for the next trophic level and thus potentially affect the recruitment of higher trophic levels.
Spatial and temporal variability of zooplankton–phytoplankton interactions in a large subtropical shallow lake dominated by non-toxic cyanobacteria
Authors: Rosa Luana Morais da , Cardoso Luciana de Souza , Crossetti Luciane Oliveira , da Motta-Marques David
Published: March 2016

The size-specific and composition relationships between zooplankton and phytoplankton were evaluated in a large subtropical lake, as well as the influence of environmental variability on spatial scale considering temporal variation. Seasonal sampling was conducted for 2 years, covering three areas (south, centre and north) and the pelagic and littoral zones in Mangueira Lake (southern Brazil). The zooplankton to phytoplankton biomass ratio, usually, was very low, indicating a weak top-down control on phytoplankton; however, the strength of this interaction varied with zooplankton composition and temporal or spatial variability of the environmental factors. Environmental, bottom-up and probably top-down forces involved the structure of zooplankton, whereas phytoplankton was mainly controlled by nutrients. The phytoplankton predominant biomass consisted of colonial forms of non-toxic cyanobacteria. Rotifers (90–150µm) were more able to benefit from phytoplankton production, whereas large-bodied zooplankton, when present in higher biomass, were not related to phytoplankton. High contribution of small ciliates and significant positive correlations between zooplankton and total phosphorus presuppose that microbial food webs primarily sustain the macro-zooplankton production in this system. The environmental variability induced by wind action or diversification of niches also played a substantial role in the structure of the plankton community, and the strength of zooplankton–phytoplankton interactions.
Diosgenin effectively suppresses skin inflammation induced by phthalic anhydride in IL-4/Luc/CNS-1 transgenic mice
Authors: Kim Ji Eun , Go Jun , Koh Eun Kyoung , Song Sung Hwa , Sung Ji Eun , Lee Hyun Ah , Kim Dong Seob , Son Hong Joo , Lee Hee Seob , Lee Chung Yeoul , Hong Jin Tae , Hwang Dae Youn
Published: March 2016

To quantitatively evaluate the therapeutic effects of diosgenin (DG) and investigate the role of IL-4 on skin inflammation, alterations in luciferase-derived signal and general phenotype biomarkers were measured in IL-4/Luc/CNS-1 transgenic mice with phthalic anhydride (PA)-induced skin inflammation after treatment with DG for 4 weeks. High levels of luciferase-derived signal detected in the abdominal region and submandibular lymph node (SL) of the PA treated group was significantly decreased by 67–88% in the PA + DG cotreated group. Furthermore, the weight of the lymph node and spleen, IgE concentration, epidermis thickness, and number of infiltrated mast cells were lower in the PA + DG treated group than the PA + Vehicle treated group. Moreover, expression of IL-6 and vascular endothelial growth factor (VEGF) also decreased in the PA + DG cotreated group. These results suggest that PA-induced skin inflammation could be successfully suppressed by DG treatment in IL-4/Luc/CNS-1 Tg mice through attenuation of IL-4 and IL-6 expression, as well as decreased IgE concentration and mast cells infiltration.
Tensions and fissures: the politics of standardised testing and accountability in Ontario, 1995–2015
Authors: Pinto Laura Elizabeth
Published: March 2016

While Ontario has received international accolades for its enactment of province‐wide standardised testing upon the formation of the Education Quality and Accountability Office (EQAO), a closer look at provincial assessments over a 20‐year span reveals successes as well as systemic tensions and fissures. The purpose of this paper is twofold. First, it offers a socio‐historical account of EQAO policy and programme enactment. Second, it offers insight into the less‐publicised politics of enactment within systems with respect to principles and methods of accountability and their link to instructional systems. Data and findings from various sources shed light on the realities of struggles, tensions in macro‐political consensus and dissensus among various stakeholders, and the micro‐politics at the school and district levels.
School curriculum in Japan
Authors: Nakayasu Chie
Published: March 2016

This article examines Japanese education system especially relevant to the school curriculum, which might support Japanese high performance in the OECD's Programme for International Student Assessment (PISA), mainly through Japanese policy documents. The Japanese education systems have been constructed by the local context of society and politics, and it is hard to analyse the reasons why Japan has seen better results in the previous PISA assessments than other OECD countries. However, the 2008–2009 revision of the Course of Study (the national curriculum in Japan) shows that the Japanese government was really concerned about the decline of Japan's ranking in the previous PISA assessments and revised the Course of Study in response to children's skills which the PISA aimed to measure (key competencies). The Japanese government has placed importance on the cultivation of human resources which are necessary to compete within the international community, and the PISA has had a large effect on the direction of Japanese education.
Learning not borrowing from the Queensland education system: lessons on curricular, pedagogical and assessment reform
Authors: Mills Martin , McGregor Glenda
Published: March 2016

This paper provides a detailed account of the Queensland education system's engagement with reforming curriculum, pedagogies and assessment. In so doing, it responds to the University College London's Institute of Education report on ‘high‐performing’ jurisdictions, of which Queensland, Australia, was identified as one. In this report, nine issues and choices in relation to ‘instructional systems’ confronting a new education minister (or secretary) are considered. This paper details the strengths of the Queensland education system in relation to curriculum, pedagogy and assessment, whilst acknowledging that particular aspects of the global and national Australian contexts, alongside internal Queensland politics, can inhibit the ongoing work of the very processes that led to Queensland being identified in the Institute of Education report as a ‘high‐performing jurisdiction’. We conclude by arguing that minsters of education need to take a longer view of educational reform than is currently the case and that quick fixes determined by electoral policy cycles need to be avoided. Learning about and from one's own system as well as from others requires a depth of analysis and time that is often not conducive to such policy cycles.
Impact attenuation of protective boxing and taekwondo headgear
Authors: O'Sullivan David M. , Fife Gabriel P.
Published: March 2016

This study aimed to compare the impact attenuation performance of boxing and taekwondo headgear in terms of peak linear and rotational acceleration. To measure the impact attenuation of headgear, a standardized (American Society for Testing and Materials (ASTM) F‐2397) martial arts headgear striker was used to impart impacts to a 50th Percentile Male Hybrid III Crash Test Dummy head and neck complex. Two boxing (Adidas and Greenhill) and two taekwondo (Adidas and Nike) headgear, approved by the Association Internationale de Boxe Amateur and the World Taekwondo Federation (WTF), were selected. Each of the selected headgear was fitted to the Hybrid III head and subsequently subjected to five impacts at the front and side with a maximum impact interim time of 60 seconds by the rotating striker at 8 ± 0.3 m/s. Linear and rotational acceleration were recorded at 10,000 Hz. There were significant interactions of the impact location and brand on the rotational acceleration, F(3,40) = 6.7, p < .05. There were significant main effects of both impact location F(1,40) = 9.07, p < .05 and headgear brand F(3,40) = 9.9, p < .05 on the linear acceleration. Pairwise comparisons show significant differences between the front and side for both linear and rotational acceleration. The headgear tested failed the ASTM high impact test requirement to reduce the linear acceleration to below a threshold of 150 g. Further development of headgear to reduce impact linear and rotational acceleration magnitudes should be called for by the relevant sport governing bodies and initiated by headgear manufactures.
Absence of MHC class II on cDCs results in microbial-dependent intestinal inflammation
Authors: Loschko Jakob , Schreiber Heidi A. , Rieke Gereon J. , Esterházy Daria , Meredith Matthew M. , Pedicord Virginia A. , Yao Kai-Hui , Caballero Silvia , Pamer Eric G. , Mucida Daniel , Nussenzweig Michel C.
Published: March 2016

Conventional dendritic cells (cDCs) play an essential role in host immunity by initiating adaptive T cell responses and by serving as innate immune sensors. Although both innate and adaptive functions of cDCs are well documented, their relative importance in maintaining immune homeostasis is poorly understood. To examine the significance of cDC-initiated adaptive immunity in maintaining homeostasis, independent of their innate activities, we generated a cDC-specific Cre mouse and crossed it to a floxed MHC class II (MHCII) mouse. Absence of MHCII on cDCs resulted in chronic intestinal inflammation that was alleviated by antibiotic treatment and entirely averted under germ-free conditions. Uncoupling innate and adaptive functions of cDCs revealed that innate immune functions of cDCs are insufficient to maintain homeostasis and antigen presentation by cDCs is essential for a mutualistic relationship between the host and intestinal bacteria.
The structure of automorphic loops
Authors: Kinyon Michael , Kunen Kenneth , Phillips J. , Vojtěchovský Petr
Published: March 2016

Automorphic loops are loops in which all inner mappings are automorphisms. This variety of loops includes, for instance, groups and commutative Moufang loops.

We study uniquely

2
2

-divisible automorphic loops, particularly automorphic loops of odd order, from the point of view of the associated Bruck loops (motivated by Glauberman’s work on uniquely

2
2

-divisible Moufang loops) and the associated Lie rings (motivated by a construction of Wright). We prove that every automorphic loop

Q
Q

of odd order is solvable and contains an element of order

p
p

for every prime

p
p

dividing

|

Q

|

|Q|

, and that

|

S

|

|S|

divides

|

Q

|

|Q|

for every subloop

S
S

of

Q
Q

.

There are no finite simple nonassociative commutative automorphic loops, and there are no finite simple nonassociative automorphic loops of order less than

2500
2500

. We show that if

Q
Q

is a finite simple nonassociative automorphic loop, then the socle of the multiplication group of

Q
Q

is not regular. The existence of a finite simple nonassociative automorphic loop remains open.

Let

p
p

be an odd prime. Automorphic loops of order

p
p

or

p
2

p^2

are groups, but there exist nonassociative automorphic loops of order

p
3

p^3

, some with trivial nucleus (center) and of exponent

p
p

. We construct nonassociative “dihedral” automorphic loops of order

2
n

2n

for every

n
>
2

n>2

, and show that there are precisely

p
−
2

p-2

nonassociative automorphic loops of order

2
p

2p

, all of them dihedral.
Importance of commitment in encouraging employees’ innovative behaviour
Authors: Hakimian Fatemeh , Farid Hadi , Ismail Mohd Nazari , Nair Pradeep Kumar
Published: March 2016

Purpose

– The extremely competitive and globalized business environment directs organizations to rely on human capital to be innovative. Committed employees are needed for organizations to foster innovative behaviors. The purpose of this paper is to examine the relationship between three forms of commitment and employees’ innovative behavior.

Design/methodology/approach

– Adopted questionnaire from previous studies were distributed among employees of Malaysian Small and Medium Enterprises. A total of 219 questionnaires were analyzed via partial least square.

Findings

– Statistical results revealed significant relationships between affective and normative commitment and employees’ innovative behavior.

Originality/value

– This study offers a theoretical contribution by adding an insight into the relationship between commitment and innovative behavior. The study also provides a practical guideline for managers of Malaysian SMEs who aim to increase innovative behavior among employees by considering their level of commitment.