bluuebunny/crossref_metadata_2025 huggingface dataset:
Features in chemical kinetics. III. Attracting subspaces in a hyper-spherical representation of the reactive system
Authors: Ceccato Alessandro , Nicolini Paolo , Frezzato Diego
Published: December 2015

In this work, we deal with general reactive systems involving N species and M elementary reactions under applicability of the mass-action law. Starting from the dynamic variables introduced in two previous works [P. Nicolini and D. Frezzato, J. Chem. Phys. 138(23), 234101 (2013); 138(23), 234102 (2013)], we turn to a new representation in which the system state is specified in a (N × M)2-dimensional space by a point whose coordinates have physical dimension of inverse-of-time. By adopting hyper-spherical coordinates (a set of dimensionless “angular” variables and a single “radial” one with physical dimension of inverse-of-time) and by examining the properties of their evolution law both formally and numerically on model kinetic schemes, we show that the system evolves towards the equilibrium as being attracted by a sequence of fixed subspaces (one at a time) each associated with a compact domain of the concentration space. Thus, we point out that also for general non-linear kinetics there exist fixed “objects” on the global scale, although they are conceived in such an abstract and extended space. Moreover, we propose a link between the persistence of the belonging of a trajectory to such subspaces and the closeness to the slow manifold which would be perceived by looking at the bundling of the trajectories in the concentration space.
Random matrix techniques in quantum information theory
Authors: Collins Benoît , Nechita Ion
Published: December 2015

The purpose of this review is to present some of the latest developments using random techniques, and in particular, random matrix techniques in quantum information theory. Our review is a blend of a rather exhaustive review and of more detailed examples—coming mainly from research projects in which the authors were involved. We focus on two main topics, random quantum states and random quantum channels. We present results related to entropic quantities, entanglement of typical states, entanglement thresholds, the output set of quantum channels, and violations of the minimum output entropy of random channels.
Transient β-hairpin formation in α-synuclein monomer revealed by coarse-grained molecular dynamics simulation
Authors: Yu Hang , Han Wei , Ma Wen , Schulten Klaus
Published: December 2015

Parkinson’s disease, originating from the intrinsically disordered peptide α-synuclein, is a common neurodegenerative disorder that affects more than 5% of the population above age 85. It remains unclear how α-synuclein monomers undergo conformational changes leading to aggregation and formation of fibrils characteristic for the disease. In the present study, we perform molecular dynamics simulations (over 180 μs in aggregated time) using a hybrid-resolution model, Proteins with Atomic details in Coarse-grained Environment (PACE), to characterize in atomic detail structural ensembles of wild type and mutant monomeric α-synuclein in aqueous solution. The simulations reproduce structural properties of α-synuclein characterized in experiments, such as secondary structure content, long-range contacts, chemical shifts, and 3J(HNHCα)-coupling constants. Most notably, the simulations reveal that a short fragment encompassing region 38-53, adjacent to the non-amyloid-β component region, exhibits a high probability of forming a β-hairpin; this fragment, when isolated from the remainder of α-synuclein, fluctuates frequently into its β-hairpin conformation. Two disease-prone mutations, namely, A30P and A53T, significantly accelerate the formation of a β-hairpin in the stated fragment. We conclude that the formation of a β-hairpin in region 38-53 is a key event during α-synuclein aggregation. We predict further that the G47V mutation impedes the formation of a turn in the β-hairpin and slows down β-hairpin formation, thereby retarding α-synuclein aggregation.
Constraint methods that accelerate free-energy simulations of biomolecules
Authors: Perez Alberto , MacCallum Justin L. , Coutsias Evangelos A. , Dill Ken A.
Published: December 2015

Atomistic molecular dynamics simulations of biomolecules are critical for generating narratives about biological mechanisms. The power of atomistic simulations is that these are physics-based methods that satisfy Boltzmann’s law, so they can be used to compute populations, dynamics, and mechanisms. But physical simulations are computationally intensive and do not scale well to the sizes of many important biomolecules. One way to speed up physical simulations is by coarse-graining the potential function. Another way is to harness structural knowledge, often by imposing spring-like restraints. But harnessing external knowledge in physical simulations is problematic because knowledge, data, or hunches have errors, noise, and combinatoric uncertainties. Here, we review recent principled methods for imposing restraints to speed up physics-based molecular simulations that promise to scale to larger biomolecules and motions.
Thermal radiation and fragmentation pathways of photo-excited silicon clusters
Authors: Ferrari Piero , Janssens Ewald , Lievens Peter , Hansen Klavs
Published: December 2015

The fragmentation of laser heated silicon clusters was studied by time-of-flight mass spectrometry. For Sin+ (n = 5–19, 21), the lowest energy fragmentation pathways were identified as the metastable decay channel occurring after the primary acceleration of the ions. The radiative cooling of laser excited Sin+ (n = 5–9, 11, and 13) was quantified via its quenching effect on the amount of metastable fragmentation. The quenching varied strongly with cluster size, from no observable amount for Si7+ to a cooling constant of 3 ⋅ 105 s−1 for Si13+. In addition, based on the observed fragmentation channels, the ionization energies and the relative binding energies of the clusters were partially ordered, and several ionization energies have been bracketed more precisely.
Brush in the bath of active particles: Anomalous stretching of chains and distribution of particles
Authors: Li Hui-shu , Zhang Bo-kai , Li Jian , Tian Wen-de , Chen Kang
Published: December 2015

The interaction between polymer brush and colloidal particles has been intensively studied in the last two decades. Here, we consider a flat chain-grafted substrate immersed in a bath of active particles. Simulations show that an increase in the self-propelling force causes an increase in the number of particles that penetrate into the brush. Anomalously, the particle density inside the main body of the brush eventually becomes higher than that outside the brush at very large self-propelling force. The grafted chains are further stretched due to the steric repulsion from the intruded particles. Upon the increase of the self-propelling force, distinct stretching behaviors of the chains were observed for low and high grafting densities. Surprisingly, we find a weak descent of the average end-to-end distance of chains at high grafting density and very large force which is reminiscent of the compression effect of a chain in the active bath.
Multifunctional semiconductor micro-Hall devices for magnetic, electric, and photo-detection
Authors: Gilbertson A. M. , Sadeghi Hatef , Panchal V. , Kazakova O. , Lambert C. J. , Solin S. A. , Cohen L. F.
Published: December 2015

We report the real-space voltage response of InSb/AlInSb micro-Hall devices to local photo-excitation, electric, and magnetic fields at room temperature using scanning probe microscopy. We show that the ultrafast generation of localised photocarriers results in conductance perturbations analogous to those produced by local electric fields. Experimental results are in good agreement with tight-binding transport calculations in the diffusive regime. The magnetic, photo, and charge sensitivity of a 2 μm wide probe are evaluated at a 10 μA bias current in the Johnson noise limit (valid at measurement frequencies > 10 kHz) to be, respectively, 500 nT/√Hz; 20 pW/√Hz (λ = 635 nm) comparable to commercial photoconductive detectors; and 0.05 e/√Hz comparable to that of single electron transistors. These results demonstrate the remarkably versatile sensing attributes of simple semiconductor micro-Hall devices that can be applied to a host of imaging and sensing applications.
Ion-cyclotron instability in plasmas described by product-bi-kappa distributions
Authors: dos Santos M. S. , Ziebell L. F. , Gaelzer R.
Published: December 2015

The dispersion relation for parallel propagating waves in the ion-cyclotron branch is investigated numerically by considering that the velocity distribution of the ion population is a function of type product-bi-kappa. We investigate the effects of the non-thermal features and of the anisotropy associated with this type of distribution on the ion-cyclotron instability, as well as the influence of different forms of the electron distribution, by considering Maxwellian distributions, bi-kappa distributions, and product-bi-kappa distributions. The cases of ions described by either Maxwellian or bi-kappa distributions are also considered, for comparison. The results of the numerical analysis show that the increase in the non-thermal character associated with the anisotropic kappa distributions for ions contributes to enhance the instability as compared to that obtained in the Maxwellian case, in magnitude and in wave number range, with more significant enhancement for the case of ion product-bi-kappa distributions than for the case of ion bi-kappa distributions. It is also shown that the ion-cyclotron instability is decreased if the electrons are described by product-bi-kappa distributions, while electrons described by bi-kappa distributions lead to growth rates which are very similar to those obtained considering a Maxwellian distribution for the electron population.
Large-scale Alfvén vortices
Authors: Onishchenko O. G. , Pokhotelov O. A. , Horton W. , Scullion E. , Fedun V.
Published: December 2015

The new type of large-scale vortex structures of dispersionless Alfvén waves in collisionless plasma is investigated. It is shown that Alfvén waves can propagate in the form of Alfvén vortices of finite characteristic radius and characterised by magnetic flux ropes carrying orbital angular momentum. The structure of the toroidal and radial velocity, fluid and magnetic field vorticity, the longitudinal electric current in the plane orthogonal to the external magnetic field are discussed.
Progress of beam diagnosis system for EAST neutral beam injector
Authors: Xu Y. J. , Hu C. D. , Yu L. , Liang L. Z. , Zhang W. T. , Chen Y. , Li X.
Published: December 2015

Neutral beam injection has been recognized as one of the most effective means for plasma heating. According to the research plan of the EAST physics experiment, two sets of neutral beam injector (NBI) were built and operational in 2014. The paper presents the development of beam diagnosis system for EAST NBI and the latest experiment results obtained on the test-stand and EAST-NBI-1 and 2. The results show that the optimal divergence angle is (0.62°, 1.57°) and the full energy particle is up to 77%. They indicate that EAST NBI work properly and all targets reach or almost reach the design targets. All these lay a solid foundation for the achievement of high quality plasma heating for EAST.
Insights into cadmium diffusion mechanisms in two-stage diffusion profiles in solar-grade Cu(In,Ga)Se2 thin films
Authors: Biderman N. J. , Novak Steven W. , Sundaramoorthy R. , Haldar Pradeep , Lloyd J. R.
Published: December 2015

Cadmium diffusion experiments were performed on polished copper indium gallium diselenide (Cu(In,Ga)Se2 or CIGS) samples with resulting cadmium diffusion profiles measured by time-of-flight secondary ion mass spectroscopy. Experiments done in the annealing temperature range between 275 °C and 425 °C reveal two-stage cadmium diffusion profiles which may be indicative of multiple diffusion mechanisms. Each stage can be described by the standard solutions of Fick's second law. The slower cadmium diffusion in the first stage can be described by the Arrhenius equation D1 = 3 × 10−4 exp (− 1.53 eV/kBT) cm2 s−1, possibly representing vacancy-meditated diffusion. The faster second-stage diffusion coefficients determined in these experiments match the previously reported cadmium diffusion Arrhenius equation of D2 = 4.8 × 10−4 exp (−1.04 eV/kBT) cm2 s−1, suggesting an interstitial-based mechanism.
A classical mechanics model for the interpretation of piezoelectric property data
Authors: Bell Andrew J.
Published: December 2015

In order to provide a means of understanding, the relationship between the primary electromechanical coefficients and simple crystal chemistry parameters for piezoelectric materials, a static analysis of a 3 atom, dipolar molecule has been undertaken to derive relationships for elastic compliance sE, dielectric permittivity εX, and piezoelectric charge coefficient d in terms of an effective ionic charge and two inter-atomic force constants. The relationships demonstrate the mutual interdependence of the three coefficients, in keeping with experimental evidence from a large dataset of commercial piezoelectric materials. It is shown that the electromechanical coupling coefficient k is purely an expression of the asymmetry in the two force constants or bond compliances. The treatment is extended to show that the quadratic electrostriction relation between strain and polarization, in both centrosymmetric and non-centrosymmetric systems, is due to the presence of a non-zero 2nd order term in the bond compliance. Comparison with experimental data explains the counter-intuitive, positive correlation of k with sE and εX and supports the proposition that high piezoelectric activity in single crystals is dominated by large compliance coupled with asymmetry in the sub-cell force constants. However, the analysis also shows that in polycrystalline materials, the dielectric anisotropy of the constituent crystals can be more important for attaining large charge coefficients. The model provides a completely new methodology for the interpretation of piezoelectric and electrostrictive property data and suggests methods for rapid screening for high activity in candidate piezoelectric materials, both experimentally and by novel interrogation of ab initio calculations.
Counting graphene layers based on the light-shielding effect of Raman scattering from a substrate
Authors: Nakayama Atsuko , Hoshino Suguru , Yamada Yuh , Ohmura Ayako , Ishikawa Fumihiro
Published: December 2015

We present a method for determining the number of stacked layers in graphene by exploiting its light-shielding effect. If a substrate supporting graphene has Raman-active modes, its Raman bands can be obtained simultaneously with the G and G′ bands of graphene. The Raman intensities from the substrate decrease with increasing the number of graphene layers because of the low opacity of graphene for visible light. The relationship between the number of graphene layers n and the relative intensities In,h/I0,h from the substrate can be represented by In,h/I0,h = 0.9772n, on the basis of the optical transmittance of visible light for single-layer graphene. The method is simple, convenient, highly accurate, and can be used to count beyond six layers up to 30 layers.
Airflow acceleration performance of asymmetric surface dielectric barrier discharge actuators at different exposed needle electrode heights
Authors: Yang Liang , Yan Hui-Jie , Qi Xiao-Hua , Hua Yue , Ren Chun-Sheng
Published: December 2015

The use of plasma, created by asymmetric surface dielectric barrier discharge (ASDBD), as aerodynamic actuators to control airflows, has been of widespread concern over the past decades. For the single ASDBD, the actuator performance is dependent on the geometry of actuator and the produced plasma. In this work, a new electrode configuration, i.e., a row of needle, is taken as an exposed electrode for the ASDBD plasma actuator, and the electrode height is adjustable. The effects of different electrode heights on the airflow acceleration behavior are experimentally investigated by measuring surface potential distribution, ionic wind velocity, and mean thrust force production. It is demonstrated that the airflow velocity and thrust force increase with the exposed electrode height and the best actuator performance can be obtained when the exposed electrode is adjusted to an appropriate height. The difference, as analyzed, is mainly due to the distinct plasma spatial distributions at different exposed electrode heights.
Absorption-reduced waveguide structure for efficient terahertz generation
Authors: Pálfalvi L. , Fülöp J. A. , Hebling J.
Published: December 2015

An absorption-reduced planar waveguide structure is proposed for increasing the efficiency of terahertz (THz) pulse generation by optical rectification of femtosecond laser pulses with tilted-pulse-front in highly nonlinear materials with large absorption coefficient. The structure functions as waveguide both for the optical pump and the generated THz radiation. Most of the THz power propagates inside the cladding with low THz absorption, thereby reducing losses and leading to the enhancement of the THz generation efficiency by up to more than one order of magnitude, as compared with a bulk medium. Such a source can be suitable for highly efficient THz pulse generation pumped by low-energy (nJ-μJ) pulses at high (MHz) repetition rates delivered by compact fiber lasers.
Dusty plasma sheath-like structure in the region of lunar terminator
Authors: Popel S. I. , Zelenyi L. M. , Atamaniuk B.
Published: December 2015

The main properties of the dusty plasma layer near the surface over the illuminated and dark parts of the Moon are described. They are used to realize dusty plasma behaviour and to determine electric fields over the terminator region. Possibility of the existence of a dusty plasma sheath-like structure in the region of lunar terminator is shown. The electric fields excited in the terminator region are demonstrated to be on the order of 300 V/m. These electric fields can result in rise of dust particles of the size of 2–3 μm up to an altitude of about 30 cm over the lunar surface that explains the effect of “horizon glow” observed at the terminator by Surveyor lunar lander.
Electric field dependence of junction magnetoresistance in magnetite/semiconductor heterostructure at room temperature
Authors: Aireddy H. , Bhaumik S. , Das A. K.
Published: December 2015

We have fabricated Fe3O4/p-Si heterojunction using pulsed laser deposition technique and explored its electro-magnetic transport properties. The heterojunction exhibits backward rectifying property at all temperatures, and appraisal of giant junction magnetoresistance (JMR) is observed at room temperature (RT). Conspicuously, the variation and sign change of JMR as a function of electric field is observed at RT. The backward rectifying behavior of the device is ascribed to the highly doped p-type (p++) semiconducting nature of Fe3O4, and the origin of electric field (voltage) dependence of magnetoresistance is explained proposing electronic band diagram of Fe3O4/SiO2/p-Si heterojunction. This interesting result may have importance to integrate Si-based magnetoresistance sources in multifunctional spintronic devices.
In situ analysis of texture development from sinusoidal stress at high pressure and temperature
Authors: Li Li , Weidner Donald J.
Published: December 2015

Here, we present a new experimental protocol to investigate the relationship between texture, plastic strain, and the mechanisms of plastic deformation at high pressure and temperature. The method utilizes synchrotron X-ray radiation as the probing tool, coupled with a large-volume high pressure deformation device (D-DIA). The intensity of X-ray diffraction peaks within the spectrum of the sample is used for sampling texture development in situ. The unique feature of this study is given by the sinusoidal variation of the intensity when a sinusoidal strain is applied to the sample. For a sample of magnesium oxide at elevated pressure and temperature, we demonstrate observations that are consistent with elasto-plastic models for texture development and for diffraction-peak measurements of apparent stress. The sinusoidal strain magnitude was 3%.
Composition-induced structural, electrical, and magnetic phase transitions in AX-type mixed-valence cobalt oxynitride epitaxial thin films
Authors: Takahashi Jumpei , Hirose Yasushi , Oka Daichi , Nakao Shoichiro , Yang Chang , Fukumura Tomoteru , Harayama Isao , Sekiba Daiichiro , Hasegawa Tetsuya
Published: December 2015

Synthesis of mid- to late-transition metal oxynitrides is generally difficult by conventional thermal ammonolysis because of thermal instability. In this letter, we synthesized epitaxial thin films of AX-type phase-pure cobalt oxynitrides (CoOxNy) by using nitrogen-plasma-assisted pulsed laser deposition and investigated their structural, electrical, and magnetic properties. The CoOxNy thin films with 0 ≤ y/(x + y) ≤ 0.63 grown on MgO (100) substrates showed a structural phase transition from rock salt (RS) to zinc blend at the nitrogen content y/(x + y) ∼ 0.5. As the nitrogen content increased, the room-temperature electrical resistivity of the CoOxNy thin films monotonically decreased from the order of 105 Ω cm to 10−4 Ω cm. Furthermore, we observed an insulator-to-metal transition at y/(x + y) ∼ 0.34 in the RS-CoOxNy phase, which has not yet been reported in Co2+/Co3+ mixed-valence cobalt oxides with octahedral coordination. The low resistivity in the RS-CoOxNy phase, on the 10−3 Ω cm order, may have originated from the intermediate spin state of Co3+ stabilized by the lowered crystal field symmetry of the CoO6−nNn octahedra (n = 1, 2,…5). Magnetization measurements suggested that a magnetic phase transition occurred in the RS-CoOxNy films during the insulator-to-metal transition. These results demonstrate that low-temperature epitaxial growth is a promising approach for exploring novel electronic functionalities in oxynitrides.
Controlling threshold voltage and leakage currents in vertical organic field-effect transistors by inversion mode operation
Authors: Günther Alrun A. , Hossbach Christoph , Sawatzki Michael , Kasemann Daniel , Bartha Johann W. , Leo Karl
Published: December 2015

The interest in vertical organic transistors as a means to overcome the limitations of conventional organic field-effect transistors (OFETs) has been growing steadily in recent years. Current vertical architectures, however, often suffer from a lack of parameter control, as they are limited to certain materials and processing techniques, making a controlled shift of, e.g., the transistor threshold voltage difficult. In this contribution, we present a vertical OFET (VOFET) operating in the inversion regime. By varying the thickness or doping concentration of a p-doped layer in an otherwise n-type VOFET, we are able to shift the threshold voltage in a controlled manner from 1.61 V (for a normal n-type VOFET) to 4.83 V (for the highest doping concentration of 50 mol. %). Furthermore, it is found that low doping concentrations of 20 mol. % can improve the Off state of the VOFET through reduction of the source-drain leakage current.
Engineering spin-orbit torque in Co/Pt multilayers with perpendicular magnetic anisotropy
Authors: Huang Kuo-Feng , Wang Ding-Shuo , Lin Hsiu-Hau , Lai Chih-Huang
Published: December 2015

To address thermal stability issues for spintronic devices with a reduced size, we investigate spin-orbit torque in Co/Pt multilayers with strong perpendicular magnetic anisotropy. Note that the spin-orbit torque arises from the global imbalance of the spin currents from the top and bottom interfaces for each Co layer. By inserting Ta or Cu layers to strengthen the top-down asymmetry, the spin-orbit torque efficiency can be greatly modified without compromised perpendicular magnetic anisotropy. Above all, the efficiency builds up as the number of layers increases, realizing robust thermal stability and high spin-orbit-torque efficiency simultaneously in the multilayers structure.
Correlation between the spin Hall angle and the structural phases of early 5d transition metals
Authors: Liu Jun , Ohkubo Tadakatsu , Mitani Seiji , Hono Kazuhiro , Hayashi Masamitsu
Published: December 2015

We have studied the relationship between the structure and the spin Hall angle of the early 5d transition metals in X/CoFeB/MgO (X = Hf, Ta, W, and Re) heterostructures. Spin Hall magnetoresistance (SMR) is used to characterize the spin Hall angle of the heavy metals. Transmission electron microscopy images show that all underlayers are amorphous-like when their thicknesses are small, however, crystalline phases emerge as the thickness is increased for certain elements. We find that the heavy metal layer thickness dependence of the SMR reflects these changes in structure. The largest spin Hall angle |θSH| of Hf, Ta, W, and Re (∼0.11, 0.10, 0.23, and 0.07, respectively) is found when the dominant phase is amorphous-like. We find that the amorphous-like phase not only possesses large resistivity but also exhibits sizeable spin Hall conductivity, which both contribute to the emergence of the large spin Hall angle.
Maxwell consideration of polaritonic quasi-particle Hamiltonians in multi-level systems
Authors: Richter Steffen , Michalsky Tom , Fricke Lennart , Sturm Chris , Franke Helena , Grundmann Marius , Schmidt-Grund Rüdiger
Published: December 2015

We address the problem of the correct description of light-matter coupling for excitons and cavity photons in the case of systems with multiple photon modes or excitons, respectively. In the literature, two different approaches for the phenomenological coupling Hamiltonian can be found: Either one single Hamiltonian with a basis whose dimension equals the sum of photonic modes and excitonic resonances is used. Or a set of independent Hamiltonians, one for each photon mode, is chosen. Both are usually used equivalently for the same kind of multi-photonic systems which cannot be correct. However, identifying the suitable Hamiltonian is difficult when modeling experimental data. By means of numerical transfer matrix calculations, we demonstrate the scope of application of each approach: The first one holds only for the coupling of a single photon state to several excitons, while in the case of multiple photon modes, separate Hamiltonians must be used for each photon mode.
Thermal effects on the Raman phonon of few-layer phosphorene
Authors: Ling Zhi-Peng , Ang Kah-Wee
Published: December 2015

Two-dimensional phosphorene is a promising channel material for next generation transistor applications due to its superior carrier transport property. Here, we report the influence of thermal effects on the Raman phonon of few-layer phosphorene formed on hafnium-dioxide (HfO2) high-k dielectric. When annealed at elevated temperatures (up to 200 °C), the phosphorene film was found to exhibit a blue shift in both the out-of-plane (A1g) and in-plane (B2g and A2g) phonon modes as a result of compressive strain effect. This is attributed to the out-diffusion of hafnium (Hf) atoms from the underlying HfO2 dielectric, which compresses the phosphorene in both the zigzag and armchair directions. With a further increase in thermal energy beyond 250 °C, strain relaxation within phosphorene eventually took place. When this happens, the phosphorene was unable to retain its intrinsic crystallinity prior to annealing, as evident from the broadening of full-width at half maximum of the Raman phonon. These results provide an important insight into the impact of thermal effects on the structural integrity of phosphorene when integrated with high-k gate dielectric.
Fabry-Perot resonance enhanced electrically pumped random lasing from ZnO films
Authors: Ni P. N. , Shan C. X. , Wang S. P. , Lu Y. J. , Li B. H. , Shen D. Z.
Published: December 2015

Fabry-Perot (F-P) resonance has been introduced into Au/MgO/ZnO structure in order to improve the performance of electrically pumped random lasing in this structure. It is found that the lasing threshold of this structure is significantly reduced by introducing the F-P resonance due to the better optical confinement. Meanwhile, this structure shows improved random lasing output characteristics with less random lasing modes and strong dominant output mode due to the gain competition process. The results demonstrate that introducing F-P resonance into the random media provides an effective strategy towards controllable, high performance electrically pumped random lasers.
Quantum frequency up-conversion of continuous variable entangled states
Authors: Liu Wenyuan , Wang Ning , Li Zongyang , Li Yongmin
Published: December 2015

We demonstrate experimentally quantum frequency up-conversion of a continuous variable entangled optical field via sum-frequency-generation process. The two-color entangled state initially entangled at 806 and 1518 nm with an amplitude quadrature difference squeezing of 3.2 dB and phase quadrature sum squeezing of 3.1 dB is converted to a new entangled state at 530 and 1518 nm with the amplitude quadrature difference squeezing of 1.7 dB and phase quadrature sum squeezing of 1.8 dB. Our implementation enables the observation of entanglement between two light fields spanning approximately 1.5 octaves in optical frequency. The presented scheme is robust to the excess amplitude and phase noises of the pump field, making it a practical building block for quantum information processing and communication networks.
Colossal magnetoelectric effect in 3-1 multiferroic nanocomposites originating from ultrafine nanodomain structures
Authors: Van Lich Le , Shimada Takahiro , Miyata Kohei , Nagano Koyo , Wang Jie , Kitamura Takayuki
Published: December 2015

We investigate colossal magnetoelectric coupling through interactions between ferroelectric and ferromagnetic nanodomains in 3-1 multiferroic BaTiO3/CoFe2O4 nanocomposites using a recent real-space phase field model based on the Landau-Ginzburg theory. A hierarchical ultrafine domain structure is characteristically formed in the nanocomposites, resulting in an extremely high density of domain walls, which causes polarization domains to be more susceptible to an external magnetic field via interfacial strain-mediation. This leads to an anomalously large magnetoelectric coupling effect in the multiferroic nanocomposites. We further demonstrate that the domain configuration and consequent magnetoelectric effect are strongly dependent on the constituent phase distribution, suggesting a promising route for the rational design of multiferroic domains and magnetoelectric effects, reminiscent of recent nano-metamaterial concepts.
Self-bending symmetric cusp beams
Authors: Gong Lei , Liu Wei-Wei , Ren Yu-Xuan , Lu Yao , Li Yin-Mei
Published: December 2015

A type of self-bending symmetric cusp beams with four accelerating intensity maxima is theoretically and experimentally presented. Distinguished from the reported regular polygon beams, the symmetric cusp beams simultaneously exhibit peculiar features of natural autofocusing and self-acceleration during propagation. Further, such beams take the shape of a fine longitudinal needle-like structure at the focal region and possess the strong ability of self-healing over obstacles. All these intriguing properties were verified experimentally. Particularly, the spatial profile of the reconstructed beam exhibits spatially sculpted optical structure with four siamesed curved arms. Thus, we anticipate that the structured beam will benefit optical guiding and optofluidics in surprising ways.
Temperature dependent polarization reversal mechanism in 0.94(Bi1/2Na1/2)TiO3-0.06Ba(Zr0.02Ti0.98)O3 relaxor ceramics
Authors: Glaum Julia , Simons Hugh , Hudspeth Jessica , Acosta Matias , Daniels John E.
Published: December 2015

The temperature at which the electric field induced long-range ordered ferroelectric state undergoes transition into the short-range ordered relaxor state, TF-R, is commonly defined by the onset of strong dispersion of the dielectric permittivity. However, this combined macroscopic property and structural investigation of the polarization reversal process in the prototypical lead-free relaxor 0.94(Bi1/2Na1/2)TiO3-0.06Ba(Zr0.02Ti0.98)O3 reveals that an applied electric field can trigger depolarization and onset of relaxor-like behavior well below TF-R. The polarization reversal process can as such be described as a combination of (1) ferroelectric domain switching and (2) a reversible phase transition between two polar ferroelectric states mediated by a non-polar relaxor state. Furthermore, the threshold fields of the second, mediated polarization reversal mechanism depend strongly on temperature. These results are concomitant with a continuous ferroelectric to relaxor transition occurring over a broad temperature range, during which mixed behavior is observed. The nature of polarization reversal can be illustrated in electric-field-temperature (E-T) diagrams showing the electric field amplitudes associated with different polarization reversal processes. Such diagrams are useful tools for identifying the best operational temperature regimes for a given composition in actuator applications.
Porous silicon nanoparticles as biocompatible contrast agents for magnetic resonance imaging
Authors: Gongalsky M. B. , Kargina Yu. V. , Osminkina L. A. , Perepukhov A. M. , Gulyaev M. V. , Vasiliev A. N. , Pirogov Yu. A. , Maximychev A. V. , Timoshenko V. Yu.
Published: December 2015

We propose porous silicon nanoparticles (PSi NPs) with natural oxide coating as biocompatible and bioresorbable contrast agents for magnetic resonant imaging (MRI). A strong shortening of the transversal proton relaxation time (T2) was observed for aqueous suspensions of PSi NPs, whereas the longitudinal relaxation time (T1) changed moderately. The longitudinal and transversal relaxivities are estimated to be 0.03 and 0.4 l/(g·s), respectively, which are promising for biomedical studies. The proton relaxation is suggested to undergo via the magnetic dipole-dipole interaction with Si dangling bonds on surfaces of PSi NPs. MRI experiments with phantoms have revealed the remarkable contrasting properties of PSi NPs for medical diagnostics.
Fluctuating single sp2 carbon clusters at single hotspots of silver nanoparticle dimers investigated by surface-enhanced resonance Raman scattering
Authors: Itoh Tamitake , Yamamoto Yuko S. , Biju Vasudevanpillai , Tamaru Hiroharu , Wakida Shin-ichi
Published: December 2015

We evaluate spectral changes in surface enhanced resonance Raman scattering (SERRS) of near-single dye molecules in hotspots of single Ag nanoparticle (NP) dimers. During the laser excitation, surface enhance florescence (SEF) of dye disappeared and the number of SERRS lines decreased until finally ca. two lines remained around 1600 and 1350 cm−1, those are evidence of G and D lines of single sp2 carbon clusters. Analysis of the G and D line intensity ratios reveals the temporal fluctuation in the crystallite size of the clusters within several angstroms; whereas, broadening and splitting in the lines enable us for identifying directly the dynamics of various defects in the clusters. This analysis reveals that the detailed fluctuations of single sp2 carbon clusters, which would be impossible to gain with other microscopic methods.
Operating from different premises: the ethics of inter‐disciplinarity in health promotion
Authors: Cribb Alan
Published: December 2015

The intersectoral and interdisciplinary nature of health promotion gives rise to ethical questions. This is because health promotion depends upon alliances between people who often have different perspectives on what matters in particular cases or different visions of the good society. This paper draws on the ambivalent relationship that health promoters can have with biomedicine to illustrate and explore the nature of these ethical questions. Examples from everyday life are used to underline the familiar nature of the kinds of coalitions and compromises that are needed to work alongside others with different values to oneself. It is suggested that analogous kinds of compromise are needed in health promotion and that this requires a form of ‘diplomatic ethics' for health promoters that, in turn, raises questions about their ethical integrity.
Spatial partitioning in the use of structural woody habitat supports the cohabitation of two cod species in a large lowland river
Authors: Lieschke J. A. , Lyon J. P. , Moloney P. D. , Nicol S. J.
Published: December 2015

Many freshwater fish worldwide have been shown to use Structural Woody Habitat (SWH) for a variety of reasons. The mid reaches of the Murray River, a large lowland river in south-eastern Australia, was surveyed by boat electrofishing, to investigate the use of SWH type (hollows, rootmass and solids), SWH distance to bank (near bank, intermediate to bank and mid-channel) and the interaction between SWH type and distance to bank. The study found that Murray cod catch per unit effort (CPUE) increased in near-bank areas when hollows were a component of the SWH. The CPUE of trout cod was higher when hollows were present. However, the interactions between distance to bank and hollow SWH were complex and dependent on presence or absence of rootmass. The species-specific interactions between SWH microhabitat and distance to bank found within this study has important relevance for stream managers. The common practice of realigning SWH favours Murray cod over trout cod, which could have negative consequences for the endangered trout cod. More broadly, managers may need to consider a balance of SWH type and where it is placed in the river for the species they are targeting when rehabilitating rivers via the introduction of SWH.
Potential invasions of phytoplankton in ship ballast water at South Korean ports
Authors: Hyun Bonggil , Shin Kyoungsoon , Jang Min-Chul , Jang Pung-Guk , Lee Woo-Jin , Park Chul , Choi Keun-Hyung
Published: December 2015

We studied the phytoplankton communities in ballast water in ships that arrived at two South Korean ports. We determined the potential for phytoplankton in the ballast water to invade the South Korean marine environment, given the specific growth rates of the phytoplankton, the delay before the phytoplankton started growing, and the rate at which the phytoplankton would initially disperse in ports and bays. Most of the phytoplankton in the ballast water samples originated in countries such as China and Japan that are adjacent to South Korea, and diatoms dominated these phytoplankton communities. The abundance of phytoplankton in a sample did not appear to be related to any particular environmental parameter, including the voyage duration. However, the number of phytoplankton taxa in a sample decreased as the voyage duration increased. The survival and growth of phytoplankton communities in the South Korean marine environment were assessed, and we found that most invasions failed at the initial dispersal phase, especially when a community was introduced to pier-side seawater. However, some members of phytoplankton communities, if they were dispersed and where conditions were highly eutrophic, could grow fast enough to overcome the initial dispersal phase in South Korean ports and bays.
Genome-based establishment of a high-yielding heterotic pattern for hybrid wheat breeding
Authors: Zhao Yusheng , Li Zuo , Liu Guozheng , Jiang Yong , Maurer Hans Peter , Würschum Tobias , Mock Hans-Peter , Matros Andrea , Ebmeyer Erhard , Schachschneider Ralf , Kazman Ebrahim , Schacht Johannes , Gowda Manje , Longin C. Friedrich H. , Reif Jochen C.
Published: December 2015

Significance

Selfing species wheat are bred as pure-line varieties with stagnating yield growths. In contrast, selection gain in maize is high, owing to massive investment sustained by hybrid seed sales, coupled with an efficient exploitation of hybrid vigor. We have developed a three-step strategy for establishing a heterotic pattern, which was one of the central unsolved challenges for initiating hybrid breeding programs. The benefits of our approach are demonstrated using data for wheat, but the strategy is relevant for several autogamous crops. Our three-step approach facilitates identification of a heterotic pattern, and thus may contribute to meeting the global challenge of increasing demand for food, feed, and fuel.
Cell membrane deformation and bioeffects produced by tandem bubble-induced jetting flow
Authors: Yuan Fang , Yang Chen , Zhong Pei
Published: December 2015

Significance

Cavitation plays a pivotal role in ultrasound-generated bioeffects. Here, we report the design of an experimental system based on laser-generated tandem bubbles in a microfluidic chip and surface patterning to investigate the causal relationship between cavitation jetting-induced cell membrane deformation and resultant bioeffects. We have demonstrated that pinpoint membrane poration produced at the cell’s leading edge correlates with area strain integral, which varies significantly with standoff distance to the tandem bubble. By adjusting the standoff distance, distinctly different bioeffects (necrosis, repairable poration, or nonporation) could be produced in individual cells, providing the opportunity to probe mechanotransduction at single cell level with potential applications in disease diagnosis and treatment monitoring based on mechanical characterization of the cell.
Full and Partial Overhead Tank Cover Improves Rainbow Trout Rearing Performance
Authors: Walker Lily M , Parker Timothy M , Barnes Michael E
Published: December 2015

This study examined the effects of different overhead tank cover regimes during rearing of Rainbow Trout Onchorynchus mykiss. Three different overhead cover treatments were applied to circular tanks: near-full (98%), partial (65%), and no cover. Compared with tanks with no overhead cover, fish growth and feed conversion ratio were significantly improved in tanks with either partial cover or near-full cover. There were no significant differences in condition factor, visceral somatic index, hepatosomatic index, or hematocrit values in fish reared under either of the cover treatments. These results indicate that either partial or near-full covers may provide benefits during hatchery production of Rainbow Trout.
The electrophysiological correlates of integrated face and body-part perception
Authors: Vakli Pál , Németh Kornél , Zimmer Márta , Kovács Gyula
Published: December 2015

Previous studies have suggested that the human visual system processes faces and bodies holistically—that is, the different body parts are integrated into a unified representation. However, the time course of this integrative process is less known. In the present study, we investigated this issue by recording event-related potentials evoked by a face and two hands presented simultaneously and in different configurations. When the hands were rotated to obtain a biologically implausible configuration, a reduction of the P2 amplitude was observed relative to the condition in which the face and hands were retained in their veridical configuration and were supplemented with visual cues to highlight further the overall body posture. Our results show that the P2 component is sensitive to manipulations affecting the configuration of face and hand stimuli and suggest that the P2 reflects the operation of perceptual mechanisms responsible for the integrated processing of visually presented body parts.
Causing Trouble: Theories of Reference and Theory of Mind
Authors: Thompson J. Robert
Published: December 2015

Michael and MacLeod’s paper on theories of reference for intentional concepts addresses neglected connections between theories of reference and Theory of Mind debates. Unfortunately, their paper neither shows the negative effects of descriptivism on theories of reference for intentional concepts nor provides an adequate picture of how the sort of theory they advocate might explain either the reference of intentional concepts or the puzzles of development on which they focus. In this article, I give reasons to think that the prospects are dim for applying causal approaches to the major topics raised by Michael and MacLeod.
By moonlighting in the nucleus, villin regulates epithelial plasticity
Authors: Patnaik Srinivas , George Sudeep P. , Pham Eric , Roy Swati , Singh Kanchan , Mariadason John M. , Khurana Seema
Published: December 2015

Villin is a tissue-specific, actin-binding protein involved in the assembly and maintenance of microvilli in polarized epithelial cells. Conversely, villin is also linked with the loss of epithelial polarity and gain of the mesenchymal phenotype in migrating, invasive cells. In this study, we describe for the first time how villin can switch between these disparate functions to change tissue architecture by moonlighting in the nucleus. Our study reveals that the moonlighting function of villin in the nucleus may play an important role in tissue homeostasis and disease. Villin accumulates in the nucleus during wound repair, and altering the cellular microenvironment by inducing hypoxia increases the nuclear accumulation of villin. Nuclear villin is also associated with mouse models of tumorigenesis, and a systematic analysis of a large cohort of colorectal cancer specimens confirmed the nuclear distribution of villin in a subset of tumors. Our study demonstrates that nuclear villin regulates epithelial–mesenchymal transition (EMT). Altering the nuclear localization of villin affects the expression and activity of Slug, a key transcriptional regulator of EMT. In addition, we find that villin directly interacts with a transcriptional corepressor and ligand of the Slug promoter, ZBRK1. The outcome of this study underscores the role of nuclear villin and its binding partner ZBRK1 in the regulation of EMT and as potential new therapeutic targets to inhibit tumorigenesis.
Acute Infections, Cost per Infection and Turnaround Time in Three United States Hospital Laboratories Using Fourth-Generation Antigen-Antibody Human Immunodeficiency Virus Immunoassays
Authors: Wesolowski Laura G. , Nasrullah Muazzam , Coombs Robert W. , Rosenberg Eric , Ethridge Steven F. , Hutchinson Angela B. , Dragavon Joan , Rychert Jennifer , Nolte Frederick S. , Madory James E. , Werner Barbara G.
Published: December 2015

Background.  To improve clinical and public health outcomes through early human immunodeficiency virus (HIV) detection, fourth-generation antigen/antibody immunoassay (4IA) and supplemental testing results must be returned rapidly.

Methods.  We examined HIV testing data at Harborview Medical Center (HMC), Massachusetts General Hospital (MGH), and the Medical University of South Carolina (MUSC), which used 4IA and supplemental antibody and nucleic acid tests (NATs). At MGH and MUSC, HIV-1 Western blot (WB) and HIV-2 testing were conducted at a reference laboratory. We compared time from specimen collection to laboratory result for established (positive WB) and acute infections (reactive 4IA, negative/indeterminate WB, detectable NAT), and we calculated testing cost per positive-test result.

Results.  From 3731 (MUSC) to 19 774 (MGH) tests were conducted; 0.01% (MGH) to 0.05% (HMC) were acute infections. Each laboratory had reactive 4IA, WB-negative, or indeterminate specimens without NAT (ie, potential acute infections). Time to result was 1.5 (HMC) to 5.2 days (MGH) for acute and 1.0 (HMC) to 5.2 days (MGH) for established infections. Costs were $1054 (MGH) to $1521 (MUSC).

Conclusions.  Conducting supplemental testing in-house lowered turnaround times, which may be further reduced with rapid HIV-1/HIV-2 differentiation tests. Hospitals may benefit from quantitative NATs not requiring physician orders, so all potential acute infections receive NAT.