bluuebunny/crossref_metadata_2025 huggingface dataset:
Simultaneous binding of a cyclophane and classical intercalators to DNA: observation of FRET-mediated white light emission
Authors: Sanju Krishnankutty S. , Thurakkal Shameel , Neelakandan Prakash P. , Joseph Joshy , Ramaiah Danaboyina
Published: April 2015

FRET tuning in ternary systems consisting of DNA, an anthracene based cyclophane and a DNA mono-/bis-intercalator is reported.
Excited state lifetimes and energies of okenone and chlorobactene, exemplary keto and non-keto aryl carotenoids
Authors: Niedzwiedzki Dariusz M. , Cranston Laura
Published: April 2015

Photophysical properties of two typical aryl carotenoids, okenone and chlorobactene, were studied with application of femtosecond and microsecond time-resolved absorption spectroscopies.
Perspectives on the energy landscape of Au–Cl binary systems from the structural phase diagram of AuxCly (x + y = 20)
Authors: Tian Zhimei , Cheng Longjiu
Published: April 2015

Structural phase diagram (SPD) of AuxCly (x + y = 20) clusters.
Lignin depolymerization over Ni/C catalyst in methanol, a continuation: effect of substrate and catalyst loading
Authors: Klein Ian , Saha Basudeb , Abu-Omar Mahdi M.
Published: April 2015

In conversion of lignin the product spectrum and yield vary significantly across catalyst loading and biomass type and origin.
A general route to monoorganopnicogen(iii) (M = Sb, Bi) compounds with a pincer (N,C,N) group and oxo ligands
Authors: Strîmb Gabriela , Pöllnitz Alpár , Raţ Ciprian I. , Silvestru Cristian
Published: April 2015

General synthetic protocols for well-defined organometallic compounds of heavy pnicogens with the pincer group, 2,6-[MeN(CH2CH2)2NCH2]2C6H3, and oxo ligands are reported.
Hydrophobicity and antioxidant activity acting together for the beneficial health properties of nordihydroguaiaretic acid
Authors: Paracatu Luana Chiquetto , Quinello Gomes de Faria Carolina Maria , Zeraik Maria Luiza , Quinello Camila , Rennó Camila , Palmeira Patrícia , da Fonseca Luiz Marcos , Ximenes Valdecir Farias
Published: April 2015

Nordihydroguaiaretic acid and rosmarinic acid, phenolic compounds found in various plants and functional foods, have known anti-inflammatory properties.
Protective effect of theaflavin-enriched black tea extracts against dimethylnitrosamine-induced liver fibrosis in rats
Authors: Weerawatanakorn Monthana , Lee You-Li , Tsai Chen-Yu , Lai Ching-Shu , Wan Xiaochun , Ho Chi-Tang , Li Shiming , Pan Min-Hsiung
Published: April 2015

Theaflavin-enriched black tea markedly reduced the DMN-induced liver fibrosis in rats.
Comparative studies on the inhibitory activities of selected benzoic acid derivatives against secretory phospholipase A2, a key enzyme involved in the inflammatory pathway
Authors: Dileep K. V. , Remya C. , Cerezo J. , Fassihi A. , Pérez-Sánchez H. , Sadasivan C.
Published: April 2015

Inhibitory activities of selected benzoic acid derivatives against phospholipase A2.
Fabrication of V2O5super long nanobelts: optical, in situ electrical and field emission properties
Authors: Butt Faheem K. , Cao Chuanbao , Idrees Faryal , Tahir Muhammad , Hussain Rafaqat , Alshemary Ammar Z.
Published: April 2015

A low turn-on field of 1.4 V μm−1, carrier concentrations ofNd= 1.48 × 1018cm−3and electron mobility of 1.26 cm2V−1s−1were obtained for V2O5super long nanobelts.
Amphiphilic fullerene/ZnO hybrids as cathode buffer layers to improve charge selectivity of inverted polymer solar cells
Authors: Hu Ting , Chen Lie , Yuan Kai , Chen Yiwang
Published: April 2015

The novel fullerene derivative/ZnO hybrids are prepared as cathode buffer layers for improving the performance of inverted polymer solar cells.
Transient dynamics of magnetic Co–graphene systems
Authors: Wang Bin , Li Jianwei , Xu Fuming , Wei Yadong , Wang Jian , Guo Hong
Published: April 2015

We report the investigation of response time of spin resolved electron traversing through a magnetic Co–graphene nano-device.
Rhenium-catalyzed dehydrogenative olefination of C(sp3)–H bonds with hypervalent iodine(iii) reagents
Authors: Gu Haidong , Wang Congyang
Published: April 2015

A dehydrogenative olefination of C(sp3)–H bonds is developed by merging rhenium catalysis with an alanine-derived hypervalent iodine(iii) reagent.
Synthesis of morpholine or piperazine derivatives through gold-catalyzed cyclization reactions of alkynylamines or alkynylalcohols
Authors: Yao Liang-Feng , Wang Yuan , Huang Kuo-Wei
Published: April 2015

A gold catalyzed reaction for the preparation of morpholine and piperazine derivatives from alkynylalcohols or alkynylamines was developed.
Synthesis and characterization of monometallic rhenium(i) complexes and their application as selective sensors for copper(ii) ions
Authors: Ramdass Arumugam , Sathish Veerasamy , Velayudham Murugesan , Thanasekaran Pounraj , Umapathy Siva , Rajagopal Seenivasan
Published: April 2015

Monometallic Re(i) complexes, selective and sensitive sensor of Cu(ii) ion, show substantial enhancement in the emission intensity, quantum yield, and lifetime due to the restriction of CN isomerization.
Encrustation of cobalt doped copper ferrite nanoparticles on solid scaffold CNTs and their comparison with corresponding ferrite nanoparticles: a study of structural, optical, magnetic and photo catalytic properties
Authors: Singh Charanjit , Bansal S. , Kumar Vinod , Tikoo K. B. , Singhal Sonal
Published: April 2015

CoxCu1−xFe2O4 nanoparticles and their structural, optical, magnetic and catalytic comparison with CNTs encrusted CoxCu1−xFe2O4 nanocomposites.
First-principles calculation of metal-doped CaAlSiN3: material design for new phosphors
Authors: Jang Seunghun , Im Jino , Bang Bo Keuk , Kim Chang Hae , Chang Hyunju , Kong Ki-jeong
Published: April 2015

Sn- or Bi-doped CASN may potentially be useful as alternatives to the Eu-doped CASN phosphors.
Confined nanospace pyrolysis for synthesis of N-doped few-layer graphene-supported yolk–shell carbon hollow spheres for electrochemical sensing
Authors: Liu Sen , Zhang Yong , Wang Ziying , Yu Bo , Song Shenguan , Zhang Tong
Published: April 2015

A confined nanospace pyrolysis method has been developed for synthesis of N-doped few-layer graphene-supported yolk–shell carbon hollow spheres for electrochemical sensing.
Synthesis of a graft-copolymer adsorbent through a green route and studies on its interactions with chromium(iii) through active functional groups: kinetics and improved adsorption supported by SEM-EDX and AFM
Authors: Kanagaraj J. , Panda Rames C. , Sumathi V.
Published: April 2015

A novel adsorbent for enhanced absorption of chromium(iii).
Improvement of the photocatalytic degradation property of atomic layer deposited ZnO thin films: the interplay between film properties and functional performances
Authors: Rogé V. , Bahlawane N. , Lamblin G. , Fechete I. , Garin F. , Dinia A. , Lenoble D.
Published: April 2015

In this work, we have evidenced the impact of stoichiometry on the photocatalytic properties of ZnO nanofilms grown by atomic layer deposition (ALD).
Core–shell ultramicroporous@microporous carbon nanospheres as advanced supercapacitor electrodes
Authors: Liu Mingxian , Qian Jiasheng , Zhao Yunhui , Zhu Dazhang , Gan Lihua , Chen Longwu
Published: April 2015

Core–shell ultramicroporous@microporous carbon nanospheres were developed as advanced supercapacitor electrodes for high rate electrochemical energy storage.
Efficient aqueous-processed hybrid solar cells from a polymer with a wide bandgap
Authors: Chen Zhaolai , Liu Fangyuan , Zeng Qingsen , Cheng Zhongkai , Du Xiaohang , Jin Gan , Zhang Hao , Yang Bai
Published: April 2015

Efficient aqueous processed polymer–nanocrystal hybrid solar cells are demonstrated based on MPPV with a wide band gap. A PCE of 5.18% is achieved which is the highest for solar devices via an aqueous process. This work may provide a new way to develop hybrid solar cells.
Agarose-biofunctionalized, dual-electrospun heteronanofiber mats: toward metal-ion chelating battery separator membranes
Authors: Kim Ju-Myung , Kim Chanhoon , Yoo Seungmin , Kim Jeong-Hoon , Kim Jung-Hwan , Lim Jun-Muk , Park Soojin , Lee Sang-Young
Published: April 2015

We demonstrated an agarose-biofunctionalized, dual-electrospun heteronanofiber mat as a new class of chemically active (specifically, metal-ion chelating) separator membranes for high-performance Li-ion batteries.
Microwave-assisted synthesis and single particle spectroscopy of infrared down- and visible up-conversion in Er3+ and Yb3+ co-doped fluoride nanowires
Authors: Wawrzynczyk Dominika , Piatkowski Dawid , Mackowski Sebastian , Samoc Marek , Nyk Marcin
Published: April 2015

We report a comprehensive study on the influence of solvent and organic ligands on the up-converted emission of single particles and colloidal solutions of NaYF4 nanowires.
Multiscale simulation of charge transport in a host material, N,N′-dicarbazole-3,5-benzene (mCP), for organic light-emitting diodes
Authors: Suzuki Furitsu , Shizu Katsuyuki , Kawaguchi Hisafumi , Furukawa Shinya , Sato Tohru , Tanaka Kazuyoshi , Kaji Hironori
Published: April 2015

By considering organic molecules explicitly, we could successfully link the macroscopic charge transfer and the microscopic molecular structure directly.
Triple-signaling mechanisms-based three-in-one multi-channel chemosensor for discriminating Cu2+, acetate and ion pair mimicking AND, NOR, INH and IMP logic functions
Authors: Singh Prabhpreet , Singh Harminder , Bhargava Gaurav , Kumar Subodh
Published: April 2015

Chemosensor 1 shows three different responses towards Cu2+, acetate and Cu(OAc)2 ion pair following triple-signaling mechanisms and also demonstrate fabrication of INH, IMP, AND, NOR logic gates.
From commercial tyrosine polymers to a tailored polydopamine platform: concepts, issues and challenges en route to melanin-based bioelectronics
Authors: Ambrico Marianna , Ambrico Paolo F. , Ligonzo Teresa , Cardone Antonio , Cicco Stefania R. , d'Ischia Marco , Farinola Gianluca M.
Published: April 2015

Current issues/challenges in the development of biocompatible eumelanin-based devices ranging from commercial eumelanins through 5,6-dihydroxyindole polymers to mussel-inspired polydopamine are presented.
Surface plasmon resonance sensor based on exposed‐core microstructured optical fibres
Authors: Luan Nannan , Wang Ran , Lv Wenhua , Yao Jianquan
Published: April 2015

A surface plasmon resonance (SPR) sensor based on exposed‐core microstructured optical fibres (EC‐MOFs) is presented and numerically characterised. The exposed section (analyte channel) of the EC‐MOF is coated with a SPR supporting thin film of gold. The asymmetrically coated fibre can support two separate resonance peaks, with orthogonal polarisations (x‐ and y‐polarised peaks). Although the sensitivity of both the polarised peaks is very similar, the narrower linewidth of the y‐polarised peak provides a much enhanced signal‐to‐noise ratio. The SPR sensing performance for a large refractive index (RI) range from 1.33 to 1.42 is evaluated. The sensor has higher sensitivity for detecting the high analyte RI. The feasibility of using EC‐MOFs to develop a fast‐response, real‐time and distributed SPR sensor is determined.
Vertical type double gate tunnelling FETs with thin tunnel barrier
Authors: Kim Jang Hyun , Kim Sang Wan , Kim Hyun Woo , Park Byung‐Gook
Published: April 2015

A vertical type tunnelling field‐effect transistor (TFET) with a thin tunnel junction based on a bulk Si substrate is presented. In the authors' previously reported L‐shaped TFET, a thin tunnel barrier and a large tunnelling area were employed on the source side to achieve a steep subthreshold swing (SS) and high on‐current, which can lead to the TFET's outstanding performance. The proposed TFET devices demonstrate a SS of 32 mV/decade averaged over five decades and an Ion > 10−5 A/μm. Moreover, the on‐current can be increased easily by adjusting the height of the source. However, since a hump phenomenon in the transfer curves occurred, the hump behaviour in the proposed device was investigated. After investigating it, the hump behaviour was found to have originated from two different tunnelling regions. Moreover, their threshold voltages show different values. Using a capping layer that can be made by gradual doping, the hump behaviour can be suppressed.
Vertical and horizontal transmission enhancement between antennas using textile artificial magnetic conductor waveguide sheet
Authors: Kamardin K. , Rahim M.K.A. , Hall P.S. , Samsuri N.A.
Published: April 2015

A textile artificial magnetic conductor (AMC) waveguide sheet with a textile diamond dipole is proposed to improve wireless on‐body transmission. The sheet‐like waveguide provides an independent transmission path which can reduce the performance degradation caused by the human body. The proposed AMC sheet is made entirely of textiles for both the substrate and the conducting parts, thus making it suitable for wearable communications. Transmission characteristics between antennas are studied rigorously in free space and on‐body environments. Significant transmission enhancement is observed for all the tested orientations and positions for both free space and on‐body placements. With the presence of the AMC, the S21 has peaks of up to a maximum of −9.9 dB. This textile AMC sheet constitutes a new approach for efficient wearable wireless body‐centric communications.
Reduction of space complexity based on symmetric TMVP
Authors: Yang Chunsheng , Pan Jeng‐Shyang , Lee Chiou‐Yng , Yan Lijun
Published: April 2015

Toeplitz matrix–vector product (TMVP) decomposition is one of the high‐precision multiplication algorithms. A symmetric TMVP (STMVP) decomposition is presented and theoretical analysis shows that the space complexity of the proposed STMVP scheme is less compared with the traditional TMVP approach. Gaussian normal basis (GNB) multiplication based on the proposed architecture can be used to reduce the space complexity.
Stochastic computation of moments, mean, variance, skewness and kurtosis
Authors: Georgiou G.M. , Voigt K.
Published: April 2015

Stochastic computation of statistical moments and related quantities, such as the mean, variance, skewness and kurtosis, is performed with simple neural networks. The computed quantities can be used to estimate the parameters of input data probability distributions, gauge the normality of data, add useful features to the inputs, preprocess data and for other applications. Such neural networks can be embedded in larger ones that perform signal processing or pattern recognition tasks. Convergence to the correct values is demonstrated with experiments.
Fast and convenient implementation of iterative eigenspace‐based beamforming
Authors: Wang Cheng , Tang Jun , Yang Bin
Published: April 2015

An iterative implementation of eigenspace‐based beamforming is introduced. An approximate expression of signal subspace projection is first derived, and then the eigenspace‐based beamformer is innovatively implemented with a two‐stage beamforming scheme. The proposed method is capable of avoiding the source number estimation or subspace projection operation, which are indispensable for existing solutions. Hence, it can be fast and conveniently applied in programming. The effectiveness of the proposed technique is demonstrated by simulations.
1 × 2 wideband patch‐dipole antenna array with slot coupler
Authors: Lian Ruina , Wang Zedong , Yin Yingzeng , Wu Jianjun , Tang Zhaoyang
Published: April 2015

A 1 × 2 wideband patch‐dipole antenna array is proposed, which consists of a slot coupler, a cavity and two pairs of bow‐tie dipole antennas loaded with meandering loops. The slot coupler has two functions: one is to work as a divider and the other is to generate differential signals for bow‐tie dipole antennas. Each bow‐tie dipole antenna is conveniently and differentially fed by two parallel probes located symmetrically at both sides of the slot coupler. A prototype is fabricated and measured for verification. The experimental results show that the proposed antenna array achieves a bandwidth of 66.4% ranging from 1.59 to 3.17 GHz. Stable radiation patterns with low cross‐polarisation and a flat gain fluctuating in the range of 10.2 ± 1.5 dBi are found over the whole frequency band.
Feedback control of oxygen uptake profiles during robotics‐assisted treadmill exercise
Authors: Schindelholz Matthias , Hunt Kenneth J.
Published: April 2015

Gait rehabilitation robots have potential for cardiovascular rehabilitation of patients with neurological deficits. A novel method was developed to guide exercise intensity by feedback control of oxygen uptake rate with a focus on tracking ramps as typically applied in maximal exercise testing. This approach is important as prior observations have noted a non‐linear oxygen uptake response to increasing work rate, whereas a linear progression of exercise intensity is desirable. The proposed oxygen‐uptake controller has embedded within it a human‐in‐the‐loop feedback system for control of mechanical work rate which takes its target work rate from the automatic oxygen uptake control loop. Results of step and ramp tracking of target oxygen‐uptake profiles, and disturbance rejection tests, demonstrated the technical feasibility and accuracy of the approach. Comparison with open‐loop tests demonstrated clearly that the feedback system linearises the oxygen‐uptake response and that linear progression of exercise intensity leads to higher peak oxygen uptake values. Further work will focus on clinical feasibility and the potential for cardiovascular rehabilitation in patients with neurological deficits.
Unsupervised feature learning based on sparse coding and spectral clustering for segmentation of synthetic aperture radar images
Authors: Rahmani Masoumeh , Akbarizadeh Gholamreza
Published: April 2015

Synthetic aperture radar (SAR) image segmentation is fundamental for the interpretation and understanding of these images. In this process, the representation of SAR image features plays an important role. Spectral clustering is an image segmentation method making it possible to combine features and cues. This study presents a new spectral clustering method using unsupervised feature learning (UFL). In this method, the SAR image is primarily processed by the non‐negative matrix factorisation (NMF) algorithm and then non‐negative features containing spatial structure information are extracted. Afterwards, the extracted features are learned using a sparse coding algorithm to increase the discrimination power of the features. Sparse coding is an unsupervised learning algorithm which finds the patterns or high‐level semantics of the data. Ultimately, the SAR image segmentation operation is performed by applying spectral clustering on learned features. In this method, sparse coding learns features and simultaneously creates the similarity function required in spectral clustering through the production of sparse coefficients. Therefore this method avoids the Gaussian similarity function, which has a problem with scale parameter adjustment that is one of the drawbacks of spectral clustering methods. The results demonstrate that, compared with wavelet and GLCM features, NMF features manage to obtain more meaningful information and provide a better SAR image segmentation result. The results have also demonstrated that SAR image segmentation using learned features is significantly improved compared with segmentation by unlearned features. The experimental results indicate the effect of UFL on SAR image segmentation.
Magnetic metamaterial analog of electromagnetically induced transparency and absorption
Authors: Zhu Lei , Meng Fan-Yi , Dong Liang , Wu Qun , Che Bang-Jun , Gao Ju , Fu Jia-Hui , Zhang Kuang , Yang Guo-Hui
Published: April 2015

In this paper, it is theoretically demonstrated that the electromagnetically induced transparency (EIT) and absorption (EIA) can be achieved in a magnetic metamaterial. Unit cell of metamaterial consists of a split ring resonator and an “I” shaped cut-wire pair, which serves as a bright resonator and a dark resonator, respectively. It is found that the EIT effect in metamaterial results from the magnetic interaction between bright and dark resonators. A classical model is also introduced to describe the EIT behavior in magnetic metamaterial, and its analytical results are in good agreement with numerical results. Significantly, by controlling the space separation between resonators, we can obtain the destructive and constructive interferences, and thus observe the transition between EIT and EIA. These results may achieve potential applications on enhancing the nonlinear interaction.
Stability of aerosol droplets in Bessel beam optical traps under constant and pulsed external forces
Authors: David Grégory , Esat Kıvanç , Hartweg Sebastian , Cremer Johannes , Chasovskikh Egor , Signorell Ruth
Published: April 2015

We report on the dynamics of aerosol droplets in optical traps under the influence of additional constant and pulsed external forces. Experimental results are compared with simulations of the three-dimensional droplet dynamics for two types of optical traps, the counter-propagating Bessel beam (CPBB) trap and the quadruple Bessel beam (QBB) trap. Under the influence of a constant gas flow (constant external force), the QBB trap is found to be more stable compared with the CPBB trap. By contrast, under pulsed laser excitation with laser pulse durations of nanoseconds (pulsed external force), the type of trap is of minor importance for the droplet stability. It typically needs pulsed laser forces that are several orders of magnitude higher than the optical forces to induce escape of the droplet from the trap. If the droplet strongly absorbs the pulsed laser light, these escape forces can be strongly reduced. The lower stability of absorbing droplets is a result of secondary thermal processes that cause droplet escape.
Electron scattering and transport in liquid argon
Authors: Boyle G. J. , McEachran R. P. , Cocks D. G. , White R. D.
Published: April 2015

The transport of excess electrons in liquid argon driven out of equilibrium by an applied electric field is revisited using a multi-term solution of Boltzmann’s equation together with ab initio liquid phase cross-sections calculated using the Dirac-Fock scattering equations. The calculation of liquid phase cross-sections extends previous treatments to consider multipole polarisabilities and a non-local treatment of exchange, while the accuracy of the electron-argon potential is validated through comparison of the calculated gas phase cross-sections with experiment. The results presented highlight the inadequacy of local treatments of exchange that are commonly used in liquid and cluster phase cross-section calculations. The multi-term Boltzmann equation framework accounting for coherent scattering enables the inclusion of the full anisotropy in the differential cross-section arising from the interaction and the structure factor, without an a priori assumption of quasi-isotropy in the velocity distribution function. The model, which contains no free parameters and accounts for both coherent scattering and liquid phase screening effects, was found to reproduce well the experimental drift velocities and characteristic energies.
High resolution coherent three dimensional spectroscopy of NO2
Authors: Wells Thresa A. , Muthike Angelar K. , Robinson Jessica E. , Chen Peter C.
Published: April 2015

Expansion from coherent 2D spectroscopy to coherent 3D spectroscopy can provide significant advantages when studying molecules that have heavily perturbed energy levels. This paper illustrates such advantages by demonstrating how high resolution coherent 3D (HRC3D) spectroscopy can be used to study a portion of the visible spectrum of nitrogen dioxide. High resolution coherent 2D spectra usually contain rotational and vibrational patterns that are easy to analyze, but severe congestion and complexity preclude its effective use for many parts of the NO2 spectrum. HRC3D spectroscopy appears to be much more effective; multidimensional rotational and vibrational patterns produced by this new technique are easy to identify even in the presence of strong perturbations. A method for assigning peaks, which is based upon analyzing the resulting multidimensional patterns, has been developed. The higher level of multidimensionality is useful for reducing uncertainty in peak assignments, improving spectral resolution, providing simultaneous information on multiple levels and states, and predicting, verifying, and categorizing peaks.
Proposed linear energy transfer areal detector for protons using radiochromic film
Authors: Mayer Rulon , Lin Liyong , Fager Marcus , Douglas Dan , McDonough James , Carabe Alejandro
Published: April 2015

Radiation therapy depends on predictably and reliably delivering dose to tumors and sparing normal tissues. Protons with kinetic energy of a few hundred MeV can selectively deposit dose to deep seated tumors without an exit dose, unlike x-rays. The better dose distribution is attributed to a phenomenon known as the Bragg peak. The Bragg peak is due to relatively high energy deposition within a given distance or high Linear Energy Transfer (LET). In addition, biological response to radiation depends on the dose, dose rate, and localized energy deposition patterns or LET. At present, the LET can only be measured at a given fixed point and the LET spatial distribution can only be inferred from calculations. The goal of this study is to develop and test a method to measure LET over extended areas. Traditionally, radiochromic films are used to measure dose distribution but not for LET distribution. We report the first use of these films for measuring the spatial distribution of the LET deposited by protons. The radiochromic film sensitivity diminishes for large LET. A mathematical model correlating the film sensitivity and LET is presented to justify relating LET and radiochromic film relative sensitivity. Protons were directed parallel to radiochromic film sandwiched between solid water slabs. This study proposes the scaled-normalized difference (SND) between the Treatment Planning system (TPS) and measured dose as the metric describing the LET. The SND is correlated with a Monte Carlo (MC) calculation of the LET spatial distribution for a large range of SNDs. A polynomial fit between the SND and MC LET is generated for protons having a single range of 20 cm with narrow Bragg peak. Coefficients from these fitted polynomial fits were applied to measured proton dose distributions with a variety of ranges. An identical procedure was applied to the protons deposited from Spread Out Bragg Peak and modulated by 5 cm. Gamma analysis is a method for comparing the calculated LET with the LET measured using radiochromic film at the pixel level over extended areas. Failure rates using gamma analysis are calculated for areas in the dose distribution using parameters of 25% of MC LET and 3 mm. The processed dose distributions find 5%–10% failure rates for the narrow 12.5 and 15 cm proton ranges and 10%–15% for proton ranges of 15, 17.5, and 20 cm and modulated by 5 cm. It is found through gamma analysis that the measured proton energy deposition in radiochromic film and TPS can be used to determine LET. This modified film dosimetry provides an experimental areal LET measurement that can verify MC calculations, support LET point measurements, possibly enhance biologically based proton treatment planning, and determine the polymerization process within the radiochromic film.
Extended theory of the Taylor problem in the plasmoid-unstable regime
Authors: Comisso L. , Grasso D. , Waelbroeck F. L.
Published: April 2015

A fundamental problem of forced magnetic reconnection has been solved taking into account the plasmoid instability of thin reconnecting current sheets. In this problem, the reconnection is driven by a small amplitude boundary perturbation in a tearing-stable slab plasma equilibrium. It is shown that the evolution of the magnetic reconnection process depends on the external source perturbation and the microscopic plasma parameters. Small perturbations lead to a slow nonlinear Rutherford evolution, whereas larger perturbations can lead to either a stable Sweet-Parker-like phase or a plasmoid phase. An expression for the threshold perturbation amplitude required to trigger the plasmoid phase is derived, as well as an analytical expression for the reconnection rate in the plasmoid-dominated regime. Visco-resistive magnetohydrodynamic simulations complement the analytical calculations. The plasmoid formation plays a crucial role in allowing fast reconnection in a magnetohydrodynamical plasma, and the presented results suggest that it may occur and have profound consequences even if the plasma is tearing-stable.
Prolate spheroidal quantum cloak
Authors: Syue Cheng-De , Lin De-Hone
Published: April 2015

To understand the propagation behavior of an oblique incident matter wave in a three-dimensional non-spherical quantum cloak, we perform the transformation design for the prolate spheroidal coordinate system and obtain a quantum cloak with an ellipsoidal shape. The mass parameters and effective potential for the creation of a perfect prolate spheroidal invisibility region are given. The analytic representations of the cloaked matter wave and probability current in the cloaking shell are presented. Special attention is paid to the discussions of the probability current in the cloaking shell for only that current can manifestly exhibit how the wave vector of the matter wave is curved, rotated, and guided in the cloaking shell to flow around the non-spherically invisible region. With the current analysis, one shows that the presented cloak can perfectly guide the matter wave in the situation of any oblique incidence. The proposed prolate spheroidal cloak for matter waves provides the first non-spherically three-dimensional setup for quantum cloaking.
Level density of a Bose gas: Beyond the saddle point approximation
Authors: Ribeiro A. D.
Published: April 2015

The present article is concerned with the use of approximations in the calculation of the many-body density of levels ρmb(E, N) of a system with total energy E, composed by N bosons. In the mean-field framework, an integral expression for ρmb, which is proper to be performed by asymptotic expansions, can be derived. However, the standard second order steepest descent method cannot be applied to this integral when the ground-state is sufficiently populated. Alternatively, we derive a uniform formula for ρmb, which is potentially able to deal with this regime. In the case of the one-dimensional harmonic oscillator, using results found in the number theory literature, we show that the uniform formula improves the standard expression achieved by means of the second order method.
Effect of stripe height on the critical current density of spin-torque noise in a tunneling magnetoresistive read head with a low resistance area product below 1.0 Ω μm2
Authors: Endo Yasushi , Fan Peng , Yamaguchi Masahiro
Published: April 2015

To understand the spin-torque effect on the noise in tunneling magnetoresistive (TMR) read heads, the GHz range noise spectra of TMR read heads with a narrow track width (w = 36 nm), and various stripe heights (h) are investigated as a function of the external magnetic field (Hex) and dc bias current density (j). The strong noise peak intensity depends on both Hex and j, indicating that the spin-torque affects the thermal mag-noise under a positive (negative) j for a positive (negative) Hex, regardless of h in the TMR heads. Due to the increased shape anisotropy, the critical current density (jc), where the non-thermal fluctuation noise originates from the spin-torque, increases markedly as the head dimension is reduced, and the maximum value of jc is approximately +1.5 × 1012 A/m2 for a head with w = 36 nm and h = 15 nm. These results demonstrate that the non-thermal fluctuation noise originating from the spin-torque in the TMR head can be suppressed in the current density range below 1012 A/m2, as the head dimension is reduced and the shape anisotropy is increased.
Semi-quartic force fields retrieved from multi-mode expansions: Accuracy, scaling behavior, and approximations
Authors: Ramakrishnan Raghunathan , Rauhut Guntram
Published: April 2015

Semi-quartic force fields (QFF) rely on a Taylor-expansion of the multi-dimensional Born-Oppenheimer potential energy surface (PES) and are frequently used within the calculation of anharmonic vibrational frequencies based on 2nd order vibrational perturbation theory (VPT2). As such they are usually determined by differentiation of the electronic energy with respect to the nuclear coordinates. Alternatively, potential energy surfaces can be expanded in terms of multi-mode expansions, which typically do not require any derivative techniques. The computational effort to retrieve QFF from size-reduced multi-mode expansions has been studied and has been compared with standard Taylor-expansions. As multi-mode expansions allow for the convenient introduction of subtle approximations, these will be discussed in some detail. In addition, a preliminary study about the applicability of a generalized Duschinsky transformation to QFFs is provided. This transformation allows for the efficient evaluation of VPT2 frequencies of isotopologues from the PES of the parent compound and thus avoids the recalculation of PESs in different axes systems.
Tunable magnetic helicity in Mn1−xFexGe: A Monte Carlo simulation
Authors: Chen J. P. , Xie Y. L. , Yan Z. B. , Liu J.-M.
Published: April 2015

Motivated by recent experiments on B20 compound Mn1−xFexGe, we explore the variations of spin structures and magnetic helicity γm in Mn1−xFexGe as a function of concentration x, using Monte Carlo simulation. We propose a simple spin model including hybrid Dzyaloshinskii-Moriya (DM) interactions with different signs in FeGe and MnGe. The results reveal a series of spin structures with helicity γm varying continuously from negative values to positive values upon decreasing x (0.0 ≤ x ≤ 1.0). The simulated x-dependence of the spin structures is consistent with experimental observations, suggesting the validity of the present hybrid model. This study sheds light on control of magnetic helicity in helimagnets, by mixing crystals with different DM interactions.
Quantifying data retention of perpendicular spin-transfer-torque magnetic random access memory chips using an effective thermal stability factor method
Authors: Thomas Luc , Jan Guenole , Le Son , Wang Po-Kang
Published: April 2015

The thermal stability of perpendicular Spin-Transfer-Torque Magnetic Random Access Memory (STT-MRAM) devices is investigated at chip level. Experimental data are analyzed in the framework of the Néel-Brown model including distributions of the thermal stability factor Δ. We show that in the low error rate regime important for applications, the effect of distributions of Δ can be described by a single quantity, the effective thermal stability factor Δeff, which encompasses both the median and the standard deviation of the distributions. Data retention of memory chips can be assessed accurately by measuring Δeff as a function of device diameter and temperature. We apply this method to show that 54 nm devices based on our perpendicular STT-MRAM design meet our 10 year data retention target up to 120 °C.
Hot probe measurements of n-type conduction in Sb-doped ZnO microwires
Authors: Alsmadi A. M. , Masmali N. , Jia H. , Guenther J. , Abu Jeib H. , Kerr Lei L. , Eid K. F.
Published: April 2015

The charge carriers type in antimony-doped ZnO (ZnO:Sb) microwires was studied using the hot probe technique. The wires were grown by a simple thermal evaporation method. Contrary to the expected p-type behavior reported for Sb doped ZnO thin films and nanowires, our hot probe measurements of representative single Sb-doped ZnO wires show a stable n-type behavior. The hot probe technique is a simple and efficient way to determine the charge carrier type from thermoelectric measurements on a single semiconductor wire and could offer an alternative to Hall effect measurements. The technique relies on creating a temperature gradient across the wire (i.e., heating one side of the wire relative to the other) and monitoring the resulting open-circuit voltage between the two ends. We also performed Energy Dispersive X-ray Spectroscopy measurements to identify and monitor the elemental composition in these ZnO:Sb wires.
Note: Rotational Raman scattering on CO2 plasma using a volume Bragg grating as a notch filter
Authors: Klarenaar B. L. M. , Brehmer F. , Welzel S. , van der Meiden H. J. , van de Sanden M. C. M. , Engeln R.
Published: April 2015

We present a novel approach for filtering Rayleigh scattering and stray light from Raman scattering in a gas discharge, using a volume Bragg grating as a notch filter. For low frequency rotational Raman contributions, it is essential to filter out Rayleigh scattering and stray light at the laser wavelength to be able to measure an undisturbed Raman spectrum. Using the Bragg grating, having an optical density of 3.1 at the central wavelength of 532 nm and a full width at half maximum of 7 cm−1, we were able to measure a nearly full rotational CO2 spectrum (1.56 cm−1 peak-to-peak separation). The rotational temperature in a CO2 discharge was determined with an accuracy of 2%.
Towards reversible control of domain wall conduction in Pb(Zr0.2Ti0.8)O3 thin films
Authors: Gaponenko I. , Tückmantel P. , Karthik J. , Martin L. W. , Paruch P.
Published: April 2015

Control over the localised conductance recently observed at ferroelectric domain walls is key for their integration into potential nanoelectronics devices. Using a combination of piezoresponse force microscopy and local conductance mapping, we demonstrate switching between conducting and insulating behavior at 180° domain walls in epitaxial Pb(Zr0.2Ti0.8)O3 thin films subjected to ultrahigh vacuum thermal annealing or exposed to ambient conditions, respectively. The reversibility of this behavior is demonstrated in repeated annealing-exposure cycles. To explain these observations, we propose a mechanism based on changes in electrostatic and chemical boundary conditions through oxygen vacancy redistribution and the removal of surface adsorbates.
Isotropic octupolar second harmonic generation response in LaBGeO5 glass-ceramic with spherulitic precipitation
Authors: Truong Lo Nhat , Dussauze Marc , Fargin Evelyne , Santos Luis , Vigouroux Hélène , Fargues Alexandre , Adamietz Frédéric , Rodriguez Vincent
Published: April 2015

A spherulitic crystallization of the crystalline phase LaBGeO5 is generated in the 25La2O3-25B2O3-50 GeO2 glass system. Linear and nonlinear optical properties of lanthanum borogermanate glass-ceramic have been investigated at both macroscopic and microscopic scales. Polarized μ-Raman analysis has evidenced a radial distribution of the crystallites along the c-axis inside spherulites, whereas polarized μ-Second Harmonic Generation (SHG) analysis revealed intensity maxima perpendicularly to the c-axis crystallites orientation. Polarized SHG mapping of a spherulite indicate that no dipolar response along the c-axis oriented crystallites occurs despite the individual dipolar symmetry C3 of the crystallites. At a larger mm scale, the isotropic scattering of spherulites recorded from macroscopic SHG experiment in the forward direction is consistent with an average coherent octupolar response per spherulite. These SHG analyses at different scale are both in accordance with radial antiferroelectric orientation along the c-axis of crystallites inside each spherulite.
Self-amplified piezoelectric nanogenerator with enhanced output performance: The synergistic effect of micropatterned polymer film and interweaved silver nanowires
Authors: Liu Chang , Hua Bo , You Sujian , Bu Chenghao , Yu Xiaolei , Yu Zhenhua , Cheng Nian , Cai Bo , Liu Huiqin , Li Shasha , Zhang Lingling , Wang Shengxiang , Liu Kan , Zhang Nangang , Liu Wei , Guo Shishang , Zhao Xing-Zhong
Published: April 2015

A piezoelectric nanogenerator with self-amplified output is prepared with a polydimethylsiloxane (PDMS)/silver nanowire (Ag NW)/poly(vinylidene fluoride-trifluoroethylene) sandwich structure. The Ag NWs facilitate the collection of induced charge generated by the piezoelectric film, and the micro-patterned PDMS films multiply the devices sensitivity under external compression. The nanogenerator exhibits good performance, with a peak open circuit voltage of 1.2 V, and a peak short circuit current of 82 nA. These findings highlight the potential of the nanogenerator in self-powered devices and wearable energy harvesters.
Would shorter working time reduce greenhouse gas emissions? An analysis of time use and consumption in Swedish households
Authors: Nässén Jonas , Larsson Jörgen
Published: April 2015

This paper addresses the effect of working hours on energy use and greenhouse gas emissions from private consumption. Time use and consumption patterns of Swedish households are analysed to estimate the effects of changing income and availability of leisure time. The results indicate that a decrease in working time by 1% may reduce energy use and greenhouse gas emissions by about 0.7% and 0.8%, respectively. These results are mainly because of the effects of lower income and lower consumption. The partly offsetting effect of households having more time available for leisure activities is less than a tenth of the income effect. In a sketched scenario we also elaborate on the long-term impacts of a work time reduction. A gradual reduction towards a 30-hour working week in 2040 would result in a significantly slower growth of energy demand, which would also make it easier to reach climate targets.
Hydrocarbons in a coral reef ecosystem subjected to anthropogenic pressures (La Réunion Island, Indian Ocean)
Authors: Guigue Catherine , Bigot Lionel , Turquet Jean , Tedetti Marc , Ferretto Nicolas , Goutx Madeleine , Cuet Pascale
Published: April 2015

Environmental context Hydrocarbons are among the most widespread and harmful pollutants found in the aquatic media. Although they have been investigated in various temperate coastal environments, their dynamics in coral reef tropical ecosystems, which are under increasing human pressure, remain poorly understood. It was found that hydrocarbons had moderate to high concentrations, multiple origins (biogenic and anthropogenic) and could be used to track inland intrusions in fore reef waters of the eutrophicated La Saline reef ecosystem (La Réunion Island, Indian Ocean). Abstract The La Saline fringing reef, which is the most important coral reef complex of La Réunion Island, (south-western Indian Ocean), is subjected to anthropogenic pressures through river and groundwater inputs. Salinity and biogeochemical parameters (silicates, nitrates, dissolved organic carbon, chlorophyll-a), as well as aliphatic hydrocarbons (AHs) and polycyclic aromatic hydrocarbons (PAHs) were analysed in particulate and dissolved material from groundwaters, rivers, harbour, back reef, fore reef and oceanic waters in the La Saline reef area during the rainy season (February–March 2012). Particulate and dissolved AH concentration ranges were 0.07–144 and 0.06–0.58µgL–1 respectively. Particulate and dissolved PAH concentrations ranges were 4.3–326 and 28–350ng L–1 respectively. AHs, dominated by nC15, nC17, nC18 compounds or nC26, nC27, nC29, nC31 compounds, were mainly of biogenic origin (phytoplankton, bacteria, higher-plant debris) although some anthropogenic (petroleum inputs) signatures were recorded in the dissolved phase from the harbour and fore reef areas. PAHs, dominated by two- to three-ring compounds and their alkylated homologues, reflected unburned petroleum inputs, but probably also biogenic sources. From the distribution of salinity, biogeochemical parameters and hydrocarbons, we found that inland waters flowed mainly in the surface and in the southern part of reef waters and that particulate PAHs allowed tracking these inland water intrusions in fore reef waters. Finally, this pilot study highlights the uncoupling between the dynamics of AHs and PAHs in tropical environments.
Enhancing legal frameworks for biodiversity conservation in the Pacific
Authors: Techera Erika J.
Published: April 2015

The Pacific region is a biodiversity hot spot with a long history of human occupation closely linked with sustainable use of the marine environment. The health of the marine environment and its resources is of environmental, economic and socio-cultural concern, and law plays an important part in its conservation and management. Designing appropriate legal mechanisms is, however, a challenging prospect. The Pacific Island countries involve a complex environment for law and policy-makers. As a result of their colonial past, these nations are legally pluralist, with more than one legal system operating at the same time. In addition, Pacific Island countries have embraced international law, ratifying the majority of key environmental treaties and subsequently taking steps to implement their obligations, including those related to biodiversity conservation. This complicated legal landscape means that law and policy must be adopted that implements international treaties whilst also meeting the needs of local communities. A particular feature of the Pacific region is the widespread adoption of community-based marine management approaches. Their proliferation is due to a combination of underlying customary law, which has subsisted despite colonial rule, together with a willingness by governments to support local approaches. This article examines community-based marine management through a legal lens; it commences by outlining traditional rules for marine management before exploring the contemporary legal position with a focus on the hybridisation of state-based legislation and customary law. Finally, comments are made on the effectiveness of these legal approaches, as well as remaining challenges.
Subclinical mastitis disrupts oocyte cytoplasmic maturation in association with reduced developmental competence and impaired gene expression in preimplantation bovine embryos
Authors: Roth Z. , Asaf S. , Furman O. , Lavon Y. , Kalo D. , Wolfenson D. , Leitner G.
Published: April 2015

Subclinical chronic mastitis was induced to examine the effects on oocyte developmental competence. Uninfected Holstein cows were intramammary administrated with serial (every 48 h for 20 days) low doses of toxin of Staphylococcus aureus origin (Gram-positive; G+), endotoxin of Escherichia coli origin (Gram-negative; G–) or sterile saline (control). Follicular fluid of toxin- and saline-treated cows was aspirated from preovulatory follicles and used as maturation medium. Oocytes harvested from ovaries collected at the abattoir were matured and then fertilised and cultured for 8 days. The percentage of oocytes undergoing nuclear maturation, determined by meiotic nuclear stages, did not differ between groups. Cytoplasmic maturation, determined by cortical granule distribution, was affected by both toxins (P < 0.05). The percentage of oocytes cleaving to 2- and 4-cell embryos and of embryos developing to the blastocyst stage was lower in both toxin-treated groups than in the control group (P < 0.05). There was no significant difference in the total cell number in Day 8 blastocysts among the groups; however, the apoptotic index was higher in both toxin-treated groups compared with control (P < 0.05). The relative abundance of prostaglandin-endoperoxide synthase 2 (prostaglandin G/H synthase and cyclo-oxygenase; PTGS2) mRNA increased, whereas that of growth differentiation factor 9 (GDF9) decreased in matured oocytes. In addition, PTGS2 expression increased and POU class 5 homeobox 1 (POU5F1) expression decreased in 4-cell embryos developed from both G+ and G– oocytes. Thus, regardless of toxin type, subclinical mastitis disrupts oocyte cytoplasmic maturation and alters gene expression in association with reduced developmental competence.