bluuebunny/crossref_metadata_2025 huggingface dataset:
Experimental demonstration of laser to x-ray conversion enhancements with low density gold targets
Authors: Shang Wanli , Yang Jiamin , Zhang Wenhai , Li Zhichao , Deng Bo , Dong Yunsong , Zhu Tuo , Huang Chengwu , Zhan Xiayu , Mei Yu , Guo Liang , Yu Ruizhen , Li Sanwei , Jiang Shaoen , Liu Shenye , Wang Feng , Ding Yongkun , Zhang Baohan , Betti Riccardo
Published: February 2016

The enhancement of laser to x-ray conversion efficiencies using low density gold targets [W. L. Shang, J. M. Yang, and Y. S. Dong, Appl. Phys. Lett. 102, 094105 (2013)] is demonstrated. Laser to x-ray conversion efficiencies with 6.3% and 12% increases are achieved with target densities of 1 and 0.25 g/cm3, when compared with that of a solid gold target (19.3 g/cm3). Experimental data and numerical simulations are in good agreement. The enhancement is caused by larger x-ray emission zone lengths formed in low density targets, which is in agreement with the simulation results.
Experiments on metasurface carpet cloaking for audible acoustics
Authors: Faure Cédric , Richoux Olivier , Félix Simon , Pagneux Vincent
Published: February 2016

We present experiments on acoustic carpet cloaking by using a metasurface made of graded Helmholtz resonators. The thin metasurface, placed over the object to hide, is designed such that the reflection phase shifts of the resonators at the resonance frequency are tuned to compensate the shape of the object to cloak. Experimental as well as numerical results show the efficiency of the cloak at the resonance frequency. The reflection of a short pulse is also reported to inspect the broadband character of the cloak.
Reducing the group velocity of coherent radiation for upconverting the single-cycle electron density modulation
Authors: Tanaka Takashi
Published: February 2016

We present an interesting property of broadband coherent radiation emitted by a single microbunch, or a single-cycle density modulation in an electron beam passing through an undulator, and describe its application to a frequency upconversion of the single-cycle modulation. This is based on the fact that a monocycle pulse is generated by focusing the coherent radiation with a unit-magnification optical system, which propagates without diffraction like the Bessel beam, at a reduced group velocity equal to the average electron velocity in the undulator. Calculations show that a single microbunch with a length of 46-nm formed in a 2-GeV and 2-kA electron beam can be upconverted to a 4-nm long microbunch through interaction with focused coherent radiation.
Multi-layer stretchable pressure sensors using ionic liquids and carbon nanotubes
Authors: Vatani Morteza , Vatani Mohamad , Choi J. W.
Published: February 2016

A stretchable and pressure sensitive polymer capable of detecting strains was developed through the incorporation of 1-ethyl-3-methylimidazolium tetrafluoroborate as an ionic liquid (IL) into a stretchable photopolymer. The developed IL/polymer composite showed both a field effect characteristic and piezoresistivity by embedding the composite between two layers of carbon nanotube (CNT)-based stretchable electrodes. A multi-layer pressure sensitive taxel was formed using a hybrid manufacturing process, where two electrode layers were fabricated by screen printing and the IL/polymer composite was formed by casting using a mold. A composite material for the electrodes was developed through the dispersion of CNTs into a highly stretchable photo/thermal crosslinkable prepolymer. The fabricated sensor was evaluated with different forces ranging from 0 to 140 g. The experiment results showed that the developed stretchable sensor had good repeatability and reliability in detecting applied pressures.
On-chip polarized light emitters based on (6,5) chirality-sorted carbon nanotube aligned arrays
Authors: Ma Ze , Liang Shuang , Liu Yang , Wang Fanglin , Wang Sheng , Peng Lian-Mao
Published: February 2016

Electrically driven light-emitters based on carbon nanotubes are highly promising candidates for on-chip optical interconnection and nanophotonics. Here, we fabricated on-chip polarized light-emitters based on (6,5) chirality-sorted carbon nanotube aligned arrays obtained via an evaporation-induced self-assembly method. Electroluminescence results shows an impact excitation dominant mechanism originated from (6,5) defect-brightened dark exciton emission and trion emission. The degree of polarization of the carbon nanotube aligned arrays is characterized quantitatively and the average value is ∼76.8%. The importance of parallelism and orientation of nanotubes when integrated with on-chip waveguides is also discussed.
Structure evolution and piezoelectric properties across the morphotropic phase boundary of Sm-substituted BiFeO3 ceramics
Authors: Shi Xin Xin , Liu Xiao Qiang , Chen Xiang Ming
Published: February 2016

The evolution of structure, ferroelectric, and piezoelectric properties in Bi1−xSmxFe0.99Ti0.01O3 ceramics was extensively investigated within the entire morphotropic phase boundary region with 0 ≤ x ≤ 0.20. A sequential phase transition of R3c-Pna21-Pbnm with increasing Sm content was revealed by Rietveld refinement of the X-ray diffraction data together with the macroscopic ferroelectric measurements. Both ferroelectric and piezoelectric properties showed a great enhancement in the vicinity of the R3c/Pna21 (polar-to-polar) phase boundary, which should be caused by the field-induced phase transition between these two phases. Such field-induced phase transition might be essentially accompanied by a change of magnetic state, which indicated a way of controlling magnetism by means of electric field.
Treatment of multiwall carbon nanotubes based on the modified Hummers method for supercapacitor electrode materials
Authors: Ma Di , Cai Jian , Wu Xiaoxin , Xu Hongfeng , Tian Ying , Zhao Hong
Published: February 2016

An effective treatment based on the modified Hummers method was initially used to improve the electrochemical properties of multiwall carbon nanotubes (MWNTs) as high-performance electrode materials for supercapacitors. In this study, the MWNTs were treated through this modified method and characterized by transmission electron microscopy (TEM). TEM findings showed that part of the nanotubes exhibited a two-dimensional structure similar to that of the graphene sheets. The –COOH content in the MWNTs treated through the modified Hummers method in accordance with the Boehm method was 8.2%. This result indicates that the modified method can convert the hydrophobic surface of the MWNTs into a hydrophilic surface. Moreover, Brunauer–Emmett–Teller measurements suggest that the specific surface area and mesoporous volume were increased. The maximum specific capacitance of the MWNTs treated with the modified Hummers method was 179 F g−1 at a current density of 0.5 A g−1; this value reflected an increase of 371% in comparison with that of MWNT electrodes treated with nitric acid (38 F g−1). Therefore, the modified Hummers method is believed to be a good prospect for improving the electrochemical performance of the MWNT supercapacitors.
Lattice thermal conductivity of organic-inorganic hybrid perovskite CH3NH3PbI3
Authors: Qian Xin , Gu Xiaokun , Yang Ronggui
Published: February 2016

Great success has been achieved in improving the photovoltaic energy conversion efficiency of the organic-inorganic hybrid perovskite-based solar cells, but with very limited knowledge on the thermal transport in hybrid perovskites, which could affect the device lifetime and stability. Based on the potential field derived from the density functional theory calculations, we studied the lattice thermal conductivity of the hybrid halide perovskite CH3NH3PbI3 using equilibrium molecular dynamics simulations. Temperature-dependent thermal conductivity is reported from 160 K to 400 K, which covers the tetragonal phase (160–330 K) and the pseudocubic phase (>330 K). A very low thermal conductivity (0.59 W/m K) is found in the tetragonal phase at room temperature, whereas a much higher thermal conductivity is found in the pseudocubic phase (1.80 W/m K at 330 K). The low group velocity of acoustic phonons and the strong anharmonicity are found responsible for the relatively low thermal conductivity of the tetragonal CH3NH3PbI3.
Direct electro-optical pumping for hybrid CdSe nanocrystal/III-nitride based nano-light-emitting diodes
Authors: Mikulics M. , Arango Y. C. , Winden A. , Adam R. , Hardtdegen A. , Grützmacher D. , Plinski E. , Gregušová D. , Novák J. , Kordoš P. , Moonshiram A. , Marso M. , Sofer Z. , Lüth H. , Hardtdegen H.
Published: February 2016

We propose a device concept for a hybrid nanocrystal/III-nitride based nano-LED. Our approach is based on the direct electro-optical pumping of nanocrystals (secondary excitation) by electrically driven InGaN/GaN nano-LEDs as the primary excitation source. To this end, a universal hybrid optoelectronic platform was developed for a large range of optically active nano- and mesoscopic structures. The advantage of the approach is that the emission of the nanocrystals can be electrically induced without the need of contacting them. The proof of principal was demonstrated for the electro-optical pumping of CdSe nanocrystals. The nano-LEDs with a diameter of 100 nm exhibit a very low current of ∼8 nA at 5 V bias which is several orders of magnitude smaller than for those conventionally used. The leakage currents in the device layout were typically in the range of 8 pA to 20 pA/cm2 at 5 V bias. The photon-photon down conversion efficiency was determined to be 27%. Microphotoluminescence and microelectroluminescence characterization demonstrate the potential for future optoelectronics and highly secure “green” information technology applications.
Enabling automated magnetic resonance imaging-based targeting assessment during dipole field navigation
Authors: Latulippe Maxime , Felfoul Ouajdi , Dupont Pierre E. , Martel Sylvain
Published: February 2016

The magnetic navigation of drugs in the vascular network promises to increase the efficacy and reduce the secondary toxicity of cancer treatments by targeting tumors directly. Recently, dipole field navigation (DFN) was proposed as the first method achieving both high field and high navigation gradient strengths for whole-body interventions in deep tissues. This is achieved by introducing large ferromagnetic cores around the patient inside a magnetic resonance imaging (MRI) scanner. However, doing so distorts the static field inside the scanner, which prevents imaging during the intervention. This limitation constrains DFN to open-loop navigation, thus exposing the risk of a harmful toxicity in case of a navigation failure. Here, we are interested in periodically assessing drug targeting efficiency using MRI even in the presence of a core. We demonstrate, using a clinical scanner, that it is in fact possible to acquire, in specific regions around a core, images of sufficient quality to perform this task. We show that the core can be moved inside the scanner to a position minimizing the distortion effect in the region of interest for imaging. Moving the core can be done automatically using the gradient coils of the scanner, which then also enables the core to be repositioned to perform navigation to additional targets. The feasibility and potential of the approach are validated in an in vitro experiment demonstrating navigation and assessment at two targets.
Temperature dependence of seed pulse amplitude and density grating in Brillouin amplification
Authors: Lehmann G. , Spatschek K. H.
Published: February 2016

Seed pulse dynamics as well as plasma response during Brillouin amplification are investigated in the so called strong coupling regime. Due to the finite amplitudes trapping of electrons and ions may become important. These effects are not covered by the commonly used three-wave interaction equations derived from fluid theory. Therefore, here investigations based on a Vlasov model are presented. The kinetic calculations show that the density response is not as predicted by the fluid models. We find a pronounced density grating with significant particle trapping. The influence of the latter on the seed amplitude development is discussed in dependence on the electron and ion temperatures.
Competition between stimulated Raman scattering and two-plasmon decay in inhomogeneous plasma
Authors: Xiao C. Z. , Liu Z. J. , Zheng C. Y. , He X. T.
Published: February 2016

We demonstrate competitions between stimulated Raman scattering (SRS) and two-plasmon decay (TPD) in the laser polarization plane in inhomogeneous near quarter-critical density plasma by using linear convective gain analysis and two-dimensional (2D) particle-in-cell (PIC) simulations. Linear theoretical analysis implies that convective SRS occurs in a wider and lower density region than absolute SRS and has a shared occurrence region with convective TPD. This convective SRS prefers a parameter space with the laser intensity larger than the order of 1015 W/cm2 and the density scale length about several hundreds microns, which may be common in large scale direct-drive scheme, shock ignition scheme, and hybrid-drive scheme. A convective nature and saturation mechanism under these parameter regions are identified to be Langmuir decay instability and strong pump depletion. The significance of this convective SRS is shown in our 2D PIC simulations that hot electrons are reduced through suppressing the electron staged acceleration by TPD in the lower density region due to its high phase velocity. Temperature induced competitions are also studied using a relativistic modification to the Langmuir wave dispersion relation when Te>5 keV. Both absolute and convective SRS are observed to be dominant in the simulations when the temperature is as high as 10 keV.
Direct excitation of TE11 mode in a relativistic backward wave oscillator
Authors: Xiao Renzhen , Zhang Yuchuan , Li Jiawei , Song Zhimin , Sun Jun
Published: February 2016

A relativistic backward wave oscillator for directly generating TE11 mode is proposed. An axially asymmetric slow wave structure and a sectioned annular cathode are introduced to suppress the TM01 mode and excite the TE11 mode. A pre-modulation dual-cavity, which allows part of the backward power to propagate into the diode region, is adopted to optimize the electron beam bunch, indicating that the conventional design principle that the diode region and the beam-wave interaction region should be isolated can be broken to increase the interaction efficiency. Particle-in-cell simulations show that when the diode voltage is 780 kV, and beam current is 6.1 kA, a microwave with power of 2.0 GW, and frequency of 9.25 GHz can be obtained, corresponding to an efficiency of 42%. Furthermore, the main output mode is TE11 mode, and the power of the cross-polarized mode is less than 10% within the calculation time of 50 ns.
Measurements of the nonlinear beat wave produced by the interaction of counterpropagating Alfvén waves
Authors: Drake D. J. , Howes G. G. , Rhudy J. D. , Terry S. K. , Carter T. A. , Kletzing C. A. , Schroeder J. W. R. , Skiff F.
Published: February 2016

Plasma turbulence has been shown to play a critical role in many astrophysical and space environments. In the solar corona and solar wind, this turbulence involves the nonlinear interaction of kinetic Alfvén waves. In the Earth's magnetosphere, the turbulence is dominated by inertial Alfvén wave collisions. Observations of these wave–wave interactions in space and in laboratory plasma environments have shown that, in addition to the nonlinear cascade of energy to small scales, the interaction also produces nonlinear beat waves that have a frequency defined by f3±=|f1±f2|. Although the temporal behavior of the beat wave has been well documented, this paper presents the first detailed analysis of the spatial structure of the nonlinearly generated beat wave.
Enhancing photoresponsivity using MoTe2-graphene vertical heterostructures
Authors: Kuiri Manabendra , Chakraborty Biswanath , Paul Arup , Das Subhadip , Sood A. K. , Das Anindya
Published: February 2016

MoTe2 with a narrow band-gap of ∼1.1 eV is a promising candidate for optoelectronic applications, especially for the near-infrared photo detection. However, the photo responsivity of few layers MoTe2 is very small (<1 mA W−1). In this work, we show that a few layer MoTe2-graphene vertical heterostructures have a much larger photo responsivity of ∼20 mA W−1. The trans-conductance measurements with back gate voltage show on-off ratio of the vertical transistor to be ∼(0.5–1) × 105. The rectification nature of the source-drain current with the back gate voltage reveals the presence of a stronger Schottky barrier at the MoTe2-metal contact as compared to the MoTe2-graphene interface. In order to quantify the barrier height, it is essential to measure the work function of a few layers MoTe2, not known so far. We demonstrate a method to determine the work function by measuring the photo-response of the vertical transistor as a function of the Schottky barrier height at the MoTe2-graphene interface tuned by electrolytic top gating.
Simulations of peristaltic slip-flow of hydromagnetic bio-fluid in a curved channel
Authors: Ali N. , Javid K. , Sajid M.
Published: February 2016

The influence of slip and magnetic field on transport characteristics of a bio-fluid are analyzed in a curved channel. The problem is modeled in curvilinear coordinate system under the assumption that the wavelength of the peristaltic wave is larger in magnitude compared to the width of the channel. The resulting nonlinear boundary value problem (BVP) is solved using an implicit finite difference technique (FDT). The flow velocity, pressure rise per wavelength and stream function are illustrated through graphs for various values of rheological and geometrical parameters of the problem. The study reveals that a thin boundary layer exists at the channel wall for strong magnetic field. Moreover, small values of Weissenberg number counteract the curvature and make the velocity profile symmetric. It is also observed that pressure rise per wavelength in pumping region increases (decreases) by increasing magnetic field, Weissenberg number and curvature of the channel (slip parameter).
Predicting molecular scale skin-effect in electrochemical impedance due to anomalous subdiffusion mediated adsorption phenomenon
Authors: Kushagra Arindam
Published: February 2016

Anomalous subdiffusion governs the processes which are not energetically driven, on a molecular scale. This paper proposes a model to predict the response of electrochemical impedance due to such diffusion process. Previous works considered the use of fractional calculus to predict the impedance behaviour in response to the anomalous diffusion. Here, we have developed an expression which predicts the skin-effect, marked by an increase in the impedance with increasing frequency, in this regime. Negative inductances have also been predicted as a consequence of the inertial response of adsorbed species upon application of frequency-mediated perturbations. It might help the researchers in the fields of impedimetric sensors to choose the working frequency and those working in the field of batteries to choose the parameters, likewise. This work would shed some light into the molecular mechanisms governing the impedance when exposed to frequency-based perturbations like electromagnetic waves (microwaves to ionizing radiations) and in charge storage devices like batteries etc.
A numerical study of multi filament formation in metal-ion based CBRAM
Authors: Berco Dan , Tseng Tseung-Yuen
Published: February 2016

This study investigates the underlying mechanisms of multiple conductive filaments (CF) creation in metal-ion based conductive bridge RRAM (CBRAM) by using the Metropolis Monte Carlo algorithm and suggests a possible explanation for this phenomenon. The simulation method is demonstrated over a Cu/HfO2 structure, starting from a random initial distribution of oxygen vacancies (OV) defects in the resistive switching layer, to a formed CF and ending in a ruptured state. the results indicate that “Hot Spots” (HS), where agglomeration of OV trap like states for electron hopping based conduction induce local heating, create favorable energy conditions to attract diffused metal species originating from the top electrode. While HS may be created and annihilated by random OV generation and recombination processes, the precipitated metal forms a stem out of which a CF could evolve. The CF stem’s final growth stage is mainly driven by drift and diffusion. This process may lead to the formation of one or more CFs as a function of the forming bias voltage. This bias dependence is demonstrated over a large range, where the creation of a single, double and multiple CFs are shown. In addition, the reset process of the multi CF device is presented, and the experimentally observed, step like, gradual CBRAM reset is verified. The simulated results are in good agreement with experimental data and promote the idea that OV defect engineering may be used to improve CBRAM performance.
Surface nanostructuring of TIMETAL 834 using excimer laser treatment
Authors: Mahanty S. , Gouthama
Published: February 2016

Excimer pulse laser is one of the processing tools which can effectively modify the metals surface by the retention of non-equilibrium characteristics. In the present study, Ti alloy is subjected to the excimer pulsed laser treatment at a fluence of ∼5 J cm−2 in argon atmosphere. The modified surface microstructures were analysed by TEM. The phase evaluation was done through XRD and TEM/SADP (Selected Area Diffraction Pattern). The effective changes in the tribological behaviour were evaluated by fretting wear test. After 10 pulse, ultrafine grains in the size range ∼100–700 nm were observed. However, 30 pulse treated sample showed the formation of nanocrystalline surface with grain size ∼30–70 nm and nanoscale twinning of spacing ∼10 nm. The wear characteristic was found to improve after laser treatment.
Aluminium and tantalum nitride barriers against copper diffusion in solar absorbers
Authors: Kotilainen Minna , Vuoristo Petri
Published: February 2016

The thermal stability of magnetron sputtered solar absorber coatings was investigated at temperatures of 200–500°C. Diffusion barriers of aluminium (Al) and tantalum nitride (TaN x) were studied against thermal diffusion of copper substrate atoms. The diffusion barriers studied were experimental DC magnetron sputtered Al and TaN x layers between a copper substrate and an absorber coating. The absorbers were aged by means of heat treatment in air. The influence of diffusion barriers was analysed by optical and microstructural analyses before and after the ageing procedures. Without a barrier coating, copper substrate atoms diffused through the absorber to the surface, which degraded optical selectivity. The diffusion can be prevented or retarded with a dense diffusion barrier layer. The 500-nm-thick Al barrier layer prevented Cu diffusion and retained optical selectivity at 300°C. At higher temperatures, diffusion was observed but the Al barrier retarded the degradation when compared to an absorber without the barrier layer.
Characterisation of CoB–Co2B coatings by the scratch test
Authors: Bravo-Bárcenas D. , Campos-Silva I. , Cimenoglu H. , Martínez-Trinidad J. , Flores-Jiménez M. , Martinez-Gutiérrez H.
Published: February 2016

New results about the scratch practical adhesion-resistance of the CoB–Co2B/substrate system developed at the surface of CoCrMo (ASTM-F75) alloy were estimated. The boron diffusion on the surface of the cobalt alloy was conducted using the powder-pack boriding process at temperatures of 1223 and 1273 K with different exposure times for each temperature. The scratch tests over the surface of cobalt borided alloy were performed with a 200 micrometres Rockwell C diamond indenter considering a continuously increasing normal force for the entire set of experimental conditions of the boriding process. The worn tracks produced on the coating/substrate system were analysed by optical and scanning electron microscopy to estimate and identify the critical loads and failure mechanisms, respectively. The results indicated that the critical loads varied between 95 and 142 N as a function of the boride coating thicknesses with a development of various types of failure mechanisms over the surface of the coating/substrate system.
Aeronautical livery coating with icephobic property
Authors: Mazzola L.
Published: February 2016

The main problem for the aircrafts is the ice formation on critical components (leading edges, slats, vertical tails, etc … ) that decreases reliability and safety of the flights. The objectives of this work are mainly two. The former is to design and develop a new multifunctional coating with aesthetical (livery effect) and icephobic properties other than high adhesion and abrasion resistance. The latter is to design and realise a new tool to use with classical contact angle measurement techniques. This tool allows to replicate the same thermodynamic conditions (in terms of pressure and temperature) present at flight altitude. In fact it was demonstrated that the water contact angle changes, varying at the same time pressure and temperature. The experimental results corroborated the influence of temperature and pressure on the shape of the supercooled water droplet applied on the new icephobic coating. The high durability of the new anti-ice livery coating was determined thorough several mechanical tests such as cutting and tape test, pull-off tests and nanoindentation tests.
Enhanced mechanical properties of HfO2 film by nitrogen doping
Authors: Lei P. , Guo S. , Zhu J. , Dai B. , Liu G. , Wang Y. , Han J.
Published: February 2016

The chemical composition, structure and mechanical properties of hafnium oxide films with different nitrogen constituents were investigated. X-ray photoelectron spectrum analysis showed that nitrogen atoms acted as oxygen substitution and interstitial atoms. The crystalline features exhibited no change during nitrogen doping. Nevertheless, the films with high compressive stress displayed significantly enhanced mechanical properties. The enhanced mechanism could mainly be attributed to the dislocation obstacle motion by inserting nitrogen atoms.
The structure and mechanical properties of magnetron sputtered VSiN coatings
Authors: Zhao Hongjian , Ni Zenglei , Ye Fuxing
Published: February 2016

VSiN coatings with silicon content ranging from 0 to 19.8 at-% were deposited by reactive magnetron sputtering technique. The structure and mechanical properties were investigated by X-ray photoelectron spectroscopy, X-ray diffraction, scanning electron microscopy, high-resolution transmission electron microscopy, atomic force microscopy and nano-indentation CSM. The results show that the incorporation of silicon does not affect the cubic structure. VSiN coatings consist of a mixture of fcc-VN, hcp-V2N and amorphous Si3N4 phases. The incorporation of silicon results in the crystallite size refinement and the decrease of the average roughness. With the incorporation of silicon content, the growth pattern changed from continuous columnar to discontinuous columnar due to the grain refinement. The H, H/E and H3/E2 ratios of VSiN coatings first increase and then decrease and the maximum values are 27 GPa, 0.098 and 0.265 GPa, respectively, at 10.2 at-% Si. All the H, H/E and H3/E2 ratios of VSiN coatings are higher than that of vanadium nitride coating.
Synthesis and characterisation of thin films in the B–C–N triangle
Authors: Tavsanoglu T. , Jeandin M. , Addemir O.
Published: February 2016

In this study, about 400 nm thick BCN films with different compositions were grown by reactive DC magnetron sputtering of a B4C target by varying the N2/Ar proportion in the sputtering gas from 0 to 50%. The microstructures of the films were determined by FE-SEM. The chemical composition was determined by electron probe microanalyser (EPMA). The crystallinity of the films was studied by grazing incidence XRD analyses. FTIR was used to determine the chemical bonding structures. The elemental depth profiles of the films were obtained from SIMS measurements. Nanoindentation and wear tests were used to determine the mechanical and tribological properties. Hardness, elastic modulus and wear rates of BCN films were significantly decreased with the increase of nitrogen in the coating composition. The results demonstrated that thin films in the ternary triangle B–C–N with tailored properties can easily be deposited by reactive DC magnetron sputtering with varying N2 flow rates.
Identification of methylglyoxal as a major mutagen in wood and bamboo pyroligneous acids
Authors: Onoda Aya , Asanoma Masaharu , Nukaya Haruo
Published: February 2016

To identify the major mutagen in pyroligneous acid (PA), 10 wood and 10 bamboo pyroligneous acids were examined using the Ames test in Salmonella typhimurium strains TA100 and TA98. Subsequently, the mutagenic dicarbonyl compounds (DCs), glyoxal, methylglyoxal (MG), and diacetyl in PA were quantified using high-performance liquid chromatography, and the mutagenic contribution ratios for each DC were calculated relative to the mutagenicity of PA. Eighteen samples were positive for mutagens and showed the strongest mutagenicity in TA100 in the absence of S9 mix. MG had the highest mutagenic contribution ratio, and its presence was strongly correlated with the specific mutagenicity of PA. These data indicate that MG is the major mutagen in PA.
Drainage developers
Authors: Williams Ruth
Published: February 2016

Researchers identify interacting engineers of the body's lymphatic drainage system.
The BCL-2–like protein CED-9 of C. elegans promotes FZO-1/Mfn1,2– and EAT-3/Opa1–dependent mitochondrial fusion
Authors: Rolland Stéphane G. , Lu Yun , David Charles N. , Conradt Barbara
Published: February 2016

The mammalian dynamin-related guanosine triphosphatases Mfn1,2 and Opa1 are required for mitochondrial fusion. However, how their activities are controlled and coordinated is largely unknown. We present data that implicate the BCL-2–like protein CED-9 in the control of mitochondrial fusion in Caenorhabditis elegans. We demonstrate that CED-9 can promote complete mitochondrial fusion of both the outer and inner mitochondrial membrane. We also show that this fusion is dependent on the C. elegans Mfn1,2 homologue FZO-1 and the C. elegans Opa1 homologue EAT-3. Furthermore, we show that CED-9 physically interacts with FZO-1 in vivo and that the ability of CED-9 to interact with FZO-1 is important for its ability to cause mitochondrial fusion. CED-9–induced mitochondrial fusion is not required for the maintenance of mitochondrial morphology during embryogenesis or in muscle cells, at least under normal conditions and in the absence of stress. Therefore, we propose that the BCL-2–like CED-9 acts through FZO-1/Mfn1,2 and EAT-3/Opa1 to promote mitochondrial fusion in response to specific cellular signals.
Corn Area Response to Local Ethanol Markets in the United States: A Grid Cell Level Analysis
Authors: Motamed Mesbah , McPhail Lihong , Williams Ryan
Published: February 2016

We measure corn and total agricultural area response to the biofuels boom in the United States from 2006 to 2010. Specifically, we use newly available micro‐scale grid cell data to test whether a location's corn and total agricultural cultivation rose in response to the capacity of ethanol refineries in their vicinity. Based on these data, acreage in corn and overall agriculture not only grew in already‐cultivated areas but also expanded into previously uncultivated areas. Acreage in corn and total agriculture also correlated with proximity to ethanol plants, though the relationship dampened over the time period. A formal estimation of the link between acreage and ethanol refineries, however, must account for the endogenous location decisions of ethanol plants and areas of corn supply. We present historical evidence to support the use of the US railroad network as a valid instrument for ethanol plant locations. Our estimates show that a location's neighborhood refining capacity exerts strong and significant effects on acreage planted in corn and total agricultural acreage. The largest impacts of ethanol plants were felt in locations where cultivation area was relatively low. This high‐resolution evidence of ethanol impacts on local agricultural outcomes can inform researchers and policy‐makers concerned with crop diversity, environmental sustainability, and rural economic development.
A global assessment of a large monocot family highlights the need for group-specific analyses of invasiveness
Authors: Moodley Desika , Procheş Şerban , Wilson John R. U.
Published: February 2016

Significant progress has been made in understanding biological invasions recently, and one of the key findings is that the determinants of naturalization and invasion success vary from group to group. Here, we explore this variation for one of the largest plant families in the world, the Araceae. This group provides an excellent opportunity for identifying determinants of invasiveness in herbaceous plants, since it is one of the families most popular with horticulturalists, with species occupying various habitats and comprising many different life forms. We first developed a checklist of 3494 species of Araceae using online databases and literature sources. We aimed to determine whether invasiveness across the introduction–naturalization–invasion continuum is associated to particular traits within the family, and whether analyses focussed on specific life forms can reveal any mechanistic correlates. Boosted regression tree models were based on species invasion statuses as the response variables, and traits associated with human use, biological characteristics and distribution as the explanatory variables. The models indicate that biological traits such as plant life form and pollinator type are consistently strong correlates of invasiveness. Additionally, large-scale correlates such as the number of native floristic regions and number of introduced regions are also influential at particular stages in the invasion continuum. We used these traits to build a phenogram showing groups defined by the similarity of characters. We identified nine groups that have a greater tendency to invasiveness (including Alocasia , the Lemnoideae and Epipremnum ). From this, we propose a list of species that are not currently invasive for which we would recommend a precautionary approach to be taken. The successful management of plant invasions will depend on understanding such context-dependent effects across taxonomic groups, and across the different stages of the invasion process.
Prediction of missing sequences and branch lengths in phylogenomic data
Authors: Darriba Diego , Weiß Michael , Stamatakis Alexandros
Published: February 2016

Motivation: The presence of missing data in large-scale phylogenomic datasets has negative effects on the phylogenetic inference process. One effect that is caused by alignments with missing per-gene or per-partition sequences is that the inferred phylogenies may exhibit extremely long branch lengths. We investigate if statistically predicting missing sequences for organisms by using information from genes/partitions that have data for these organisms alleviates the problem and improves phylogenetic accuracy.

Results: We present several algorithms for correcting excessively long branch lengths induced by missing data. We also present methods for predicting/imputing missing sequence data. We evaluate our algorithms by systematically removing sequence data from three empirical and 100 simulated alignments. We then compare the Maximum Likelihood trees inferred from the gappy alignments and on the alignments with predicted sequence data to the trees inferred from the original, complete datasets. The datasets with predicted sequences showed one to two orders of magnitude more accurate branch lengths compared to the branch lengths of the trees inferred from the alignments with missing data. However, prediction did not affect the RF distances between the trees.

Availability and implementation: https://github.com/ddarriba/ForeSeqs

Contact: diego.darriba@h-its.org

Supplementary information: Supplementary data are available at Bioinformatics online.
Inference for the existence of hormetic dose–response relationships in toxicology studies
Authors: Kim Steven B. , Bartell Scott M. , Gillen Daniel L.
Published: February 2016

In toxicology studies hormesis refers to a dose–response relationship with a stimulatory response at low doses and an inhibitory response at high doses. In this manuscript, we particularly focus on a J-shaped dose–response relationship for binary cancer responses. We propose and examine two new flexible models for testing the hypothesis of hormesis in a Bayesian framework. The first model is parametric and enhances the flexibility of modeling a hormetic zone by using a non-linear predictor in a multistage model. The second model is non-parametric and allows multiple model specifications, weighting the contribution of each model via Bayesian model averaging (BMA). Simulation studies show that the non-parametric modeling approach with BMA provides robust sensitivity and specificity for detecting hormesis relative to the parametric approach, regardless of the shape of a hormetic zone.
Implantable cardioverter-defibrillators in adults with congenital heart disease: a systematic review and meta-analysis
Authors: Vehmeijer Jim T. , Brouwer Tom F. , Limpens Jacqueline , Knops Reinoud E. , Bouma Berto J. , Mulder Barbara J.M. , de Groot Joris R.
Published: February 2016

Aims

Sudden cardiac death is a major cause of mortality in adult congenital heart disease (ACHD) patients. The indications for implantable cardioverter-defibrillator (ICD) implantation in ACHD patients are still not well established. We aim to systematically review the literature on indications and outcome of ICD implantation in ACHD patients.

Methods and results

We performed a comprehensive search in EMBASE, MEDLINE, and Google Scholar to identify all studies on ICD implantation in ACHD patients. We used random effects models to calculate proportions and 95% confidence intervals. Of 1356 articles, 24 studies with 2162 patients were included, with a mean follow-up of 3.6 ± 0.9 years. Half of patients had tetralogy of Fallot. Mean age at implantation was 36.5 ± 5.5 years old and 66% was male. Implantable cardioverter-defibrillators were implanted for primary prevention in 53% (43.5–62.7). Overall, 24% (18.6–31.3) of patients received one or more appropriate ICD interventions (anti-tachycardia pacing or shocks) during 3.7 ± 0.9 years: 22% (16.9–28.8) of patients with primary prevention in 3.3 ± 0.3 years and 35% (26.6–45.2) of patients with secondary prevention in 4.3 ± 1.2 years. Inappropriate shocks occurred in 25% (20.1–31.0) in 3.7 ± 0.8 years and other, particularly lead-related complications in 26% (18.9–33.6) of patients in 3.8 ± 0.8 years. All-cause mortality was 10% during 3.7 ± 0.9 years.

Conclusions

In ACHD, remarkably high rates of appropriate ICD therapy were reported, both in primary and secondary prevention. Because of the young age and lower death rates, the cumulative beneficial effects are likely greater in ACHD patients than in acquired heart disease patients. However, considering the high rates of inappropriate shocks and complications, case-by-case weighing of costs and benefits, remains essential.
CD4 + T-cell subsets in inflammatory diseases: beyond the T h 1/T h 2 paradigm
Authors: Hirahara Kiyoshi , Nakayama Toshinori
Published: February 2016

CD4 + T cells are crucial for directing appropriate immune responses during host defense and for the pathogenesis of inflammatory diseases. In addition to the classical biphasic model of differentiation of T-helper 1 (T h 1) and T h 2 cells, unexpected increases in the numbers of CD4 + T-cell subsets, including T h 17, T h 9, T follicular-helper (T fh ) and T-regulatory (T reg ) cells, have been recognized. In the present review, we focus on how these various T-helper cell subsets contribute to the pathogenesis of immune-mediated inflammatory diseases. In particular, we focus on multiple sclerosis, psoriasis and asthma as typical model diseases in which multiple T-helper cell subsets have recently been suggested to play a role. We will also discuss various unique sub-populations of T-helper cells that have been identified. First, we will introduce the heterogeneous T-helper cell subsets, which are classified by their simultaneous expression of multiple key transcription factors. We will also introduce different kinds of memory-type T h 2 cells, which are involved in the pathogenesis of chronic type-2 immune-related diseases. Finally, we will discuss the molecular mechanisms underlying the generation of the plasticity and heterogeneity of T-helper cell subsets. The latest progress in the study of T-helper cell subsets has forced us to reconsider the etiology of immune-mediated inflammatory diseases beyond the model based on the T h 1/T h 2 balance. To this end, we propose another model—the pathogenic T-helper population disease-induction model—as a possible mechanism for the induction and/or persistence of immune-mediated inflammatory diseases.
Female philopatry and limited male-biased dispersal in the Ussuri tube-nosed bat, Murina ussuriensis
Authors: Flanders Jon , Inoue-Murayama Miho , Rossiter Stephen J. , Hill David A.
Published: February 2016

Male-biased dispersal and female philopatry are common traits among social mammals, often leading to elevated relatedness within social groups. However, exceptions do occur, with documented cases of female-biased dispersal, dispersal by both sexes, and philopatry of both sexes. In this study, we examined levels of dispersal and relatedness based on analyses of the mitochondrial D-loop and 12 nuclear microsatellite markers in the woodland specialist Ussuri tube-nosed bat ( Murina ussuriensis ), a relatively widespread, yet locally rare species that is thought to be threatened by loss of its forest habitats across its range. A total of 85 individuals were captured in lowland temperate forest on the island of Yakushima and 28 individuals in montane forest in Hokkaido, Japan. In the former, haplotypes showed extreme spatial clustering among females consistent with strong philopatry, but spatial mixing among males suggesting dispersal over short distances. These findings were broadly supported by microsatellite analyses, which indicated considerable genealogical structure within sampling locations but a lack of spatial structure, again indicating that some gene flow does occur in one or both sexes. The Hokkaido data, although limited, did not show these patterns and instead suggest that differences in environmental and behavioral variables may influence movement ecology of individuals at these 2 sites and consequently fine-scale genetic structure within this species.
An evaluation of hair-snaring devices for small-bodied carnivores in southwest China
Authors: Bu Hongliang , Hopkins John B. , Zhang Dan , Li Sheng , Wang Rongjiang , Yao Meng , Wang Dajun
Published: February 2016

Human population growth is a major threat to the biodiversity of mammals in China. Rapid development of infrastructure, pollution, and poor enforcement of environmental laws in China have altered the landscape and accelerated the extinction rates of mammals. To maintain biodiversity and conserve the mammals of China, it is essential to develop monitoring protocols for species of concern that are efficient, cost-effective, and current. It is now common practice for ecologists to survey mammals of interest using noninvasive sampling methods. These sampling techniques are affordable, require no handling of the target animals, and generally yield large samples. In China, such sampling methods have rarely been used and evaluated. For this study, we recorded the behavior of masked palm civets ( Paguma larvata ) and Siberian weasels ( Mustela sibirica ) to determine their relative preference for using different hair-snaring devices and evaluated the effectiveness of each device at collecting hair. Our goal was to determine which genetic sampling method(s) should be used to study masked palm civets and Siberian weasels in the future in Southwest China. In March–June of 2014, we monitored 13 hair-snare stations throughout the Main Valley of Laohegou Nature Reserve, Sichuan Province, China. Genetic analysis revealed that we collected 373 hair samples from civets and 47 hair samples from weasels over 104 and 26 sessions, respectively. Both civets and weasels seemed to prefer lure sticks to ground cubbies; however, the latter were more effective at collecting civet hair. Although glue sheets from lure sticks collected large samples of guard hair (> 10), no device in its current design was consistently effective at collecting weasel hair. We suggest researchers in Southwest China use ground cubbies as described in this study to collect hair from masked palm civets and test other cubby designs (e.g., longer gun brushes or smaller in size) for collecting hair from Siberian weasels.

人口增长是中国哺乳动物多样性危机的主要根源之一。在中国，基础建设的快速发展、环境污染，加之环境执法力度不足造成了哺乳动物的栖息地的退化，加速了动物的灭绝速率。为了维持生物多样性水平和保护中国的哺乳动物，有必要针对受关注的物种开发有效、低成本且通用的监测方法。现在，非损伤性取样方法正被生态学家普遍应用于哺乳动物的调查中。这些调查技术在成本上易于接受，不需要接触目标动物，并且通常可以得到大量可靠的样本。在中国，非损伤性取样方法的应用和评估还较少。本研究中，我们在四川省老河沟自然保护区评估了花面狸和黄鼬对毛发陷阱的访问偏好及陷阱收集动物毛发的有效性；目标是选出有效地遗传取样方法用于将来对花面狸和黄鼬的研究。从2014年3月到6月，我们在保护区主要山谷内设置了13个毛发陷阱站，在收集野生动物的毛发同时使用红外相机记录动物访问陷阱站时的行为。我们发现，相比于设置在地面的小室陷阱，花面狸和黄鼬都更喜欢访问直立的木桩陷阱，但是，小室陷阱能够更有效地收集花面狸的毛发。尽管固定有粘性薄片的木桩 陷阱能够少量收集带有直针毛的毛发（>10根）,但是我们评估的毛发陷阱都不能有效地收集黄鼬的 毛发。根据研究，我们建议研究人员在中国西南可以应用固定有枪刷的小室陷阱（如本研究中所评估的）收集花面狸的毛发，而用更长的枪刷，或者更小的小室陷阱，并固定粘性薄片收集黄鼬的毛发。
Hepatitis C Screening in People With Human Immunodeficiency Virus: Lessons Learned From Syphilis Screening
Authors: Wurcel Alysse G. , Chen Daniel D. , Fitzpatrick Rosemary E. , Grasberger Paula E. , Kirshner Caleb H. , Anderson Jordan E. , Chui Kenneth K. H. , Knox Tamsin A.
Published: February 2016

Background.  The incidence of hepatitis C virus (HCV) infection is increasing in human immunodeficiency virus (HIV)-positive men who have sex with men (MSM). New guidelines recommend annual screening for HCV, similar to recommendations for syphilis screening with rapid plasma reagin (RPR).

Methods.  This study compares the frequency of repeat HCV antibody (Ab) testing to repeat RPR testing in a retrospective chart review of 359 HCVAb-negative people living with HIV (PLWH) observed in an Infectious Diseases clinic. Patients were classified into risk groups based on sexual risk factors.

Results.  Although 85% of PLWH had repeat syphilis screening, less than two thirds had repeat HCVAb screening. The MSM status was associated with increased HCVAb and RPR testing (adjusted odds ratio, 2.6 and 5.9, respectively). Seven persons had incident HCV infection: 3 were MSM, and 4 had symptoms or abnormal laboratory results to prompt testing.

Conclusions.  Failure to find incident HCV infection in PLWH represents missed opportunities to cure HCV infection and prevent progressive liver disease. Further quality improvement studies are necessary to develop physician-focused interventions to increase HCV screening rates in PLWH.