bluuebunny/crossref_metadata_2025 huggingface dataset:
InGaAs/GaAs quantum well lasers grown on exact GaP/Si (001)
Authors: Huang Xue , Song Yuncheng , Masuda Taizo , Jung Daehwan , Lee Minjoo
Published: August 2014

InGaAs/GaAs strained quantum well lasers on both GaP and exact Si (001) via an epitaxial GaP/Si template are developed. Ridge lasers of length 1.2 mm and width 80 µm on GaP and GaP/Si templates show threshold current densities of 1.6 and 5.6 kA/cm2, respectively, in pulsed mode at room temperature. The emission wavelength of 1043 nm for lasers on GaP/Si was red shifted from 1030 nm for lasers on GaP and GaAs, due to the thermal mismatch with the Si substrate.
Global state feedback stabilisation for a class of more general high‐order non‐linear systems
Authors: Gao Fangzheng , Wu Yuqiang
Published: August 2014

This study addresses the problem of global stabilisation by state feedback for a class of high‐order non‐linear systems with more general uncertainties, to which the existing control methods are inapplicable. By introducing sign function and necessarily modifying the method of adding a power integrator, a continuous state feedback controller is successfully constructed to guarantee the global asymptotic stability of the resulting closed‐loop system. Two simulation examples are provided to illustrate the effectiveness of the proposed approach.
High‐speed quantile‐based histogram equalisation for brightness preservation and contrast enhancement
Authors: Tiwari Mayank , Gupta Bhupendra , Shrivastava Manish
Published: August 2014

In this study, the authors introduce a new histogram equalisation‐based contrast enhancement method called high‐speed quantile‐based histogram equalisation (HSQHE) suitable for high contrast digital images. The proposed method is an effective tool to deal with the ‘mean‐shift’ problem, which is a usual problem with the histogram equalisation‐based contrast enhancement methods. The main idea of HSQHE is to divide input image histogram into two or more sub‐histograms, where segmentation is based on quantile values. Since the histogram segmentation is based on the quantile values, the entire spectrum of grey level will always play an important role in enhancement process. In addition, the proposed method does not require the recursive segmentation of the histogram as in many other methods, and hence the proposed method requires less time for segmentation. The experimental results show that the performance of the proposed HSQHE method is better as compared with other existing methods available in the literature. In addition, this method preserves image brightness more accurately than the prevailing state of art and takes less time as compared with the other methods.
Short‐circuit analysis of pumped storage unit during back‐to‐back starting
Authors: Li Bin , Duan Zhitian , Wu Jianzhong
Published: August 2014

Back‐to‐back starting is a widely accepted starting method for pumped storage units. A back‐to‐back starting model of pumped storage units was built using the ElectroMagnetic Transients Program including DC (EMTDC) software package. The short‐circuit fault during back‐to‐back starting was investigated for the first time. The starting process was simulated and compared with real data from a pumped storage power plant in northeast China. The rotor speed and the effect of resistance during fault period were also discussed. The results showed that the fault current has significant magnitude and low‐frequency characteristic. Recommendations were provided to realise secure and reliable fault clearance during back‐to‐back starting based on the fault characteristics and real de‐excitation test results of the pumped storage power plant.
Hydrophobic and thermal behaviour of nylon 6 nanofibre web deposited on cotton fabric through electrospinning
Authors: Dhineshbabu N.R. , Manivasakan Palanisamy , Rajendran Venkatachalam
Published: August 2014

A nylon 6 nanofibre web was deposited on the surface of cotton fabrics using the electrospinning process. The prepared nylon 6 nanofibre‐modified cotton fabric showed remarkable hydrophobic and flame‐retardant properties. The morphology of nylon 6 nanofibres was examined by scanning electron microscopy and transmission electron microscopy. Furthermore, the surface topography of electrospun nanofibre was characterised using atomic force microscopy. The cross‐sectional view of the layered fabric morphology was observed through high‐resolution scanning electron microscopy. The hydrophobicity of the coated fabric was determined through static water contact angle measurement (132.2° for a 10 µl droplet). The flame‐retardant properties of the nylon 6 nanofibre‐modified cotton fabric and the uncoated cotton fabric were resolved with an inclined (45°) flame‐retardant testing machine. Results showed that nylon 6 nanofibre is of a superhydrophobic nature with enhanced flame‐retardant properties to cotton fabrics. This work opens up a new possibility for the development of polymer coating on cotton fabrics using the highly reliable electrospinning process.
Microfabrication of a high‐density, non‐neutral antimatter trap
Authors: Narimannezhad Alireza , Jennings Joshah , Weber Marc H. , Lynn Kelvin G.
Published: August 2014

A unique approach for the fabrication of long‐aspect ratio microtubes is presented for an antimatter trap. Conventionally, non‐neutral antimatter is stored using a Penning‐Malmberg trap, a single tube with aspect ratios being of the order of less than 10:1. Parallel microtubes with aspect ratios of 1000:1 have the potential to store many orders of magnitude more. The silicon industry has paved the way to microelectromechanical systems technologies which have been utilised in this research. Standard processes such as photolithography, deep reactive ion etching, sputtering and thermo‐compression bonding were all used; however, unique methods of these processes were developed to overcome many engineering challenges and realise successful trapping.
Qualification of a high-efficiency, gated spectrometer for x-ray Thomson scattering on the National Ignition Facility
Authors: Döppner T. , Kritcher A. L. , Neumayer P. , Kraus D. , Bachmann B. , Burns S. , Falcone R. W. , Glenzer S. H. , Hawreliak J. , House A. , Landen O. L. , LePape S. , Ma T. , Pak A. , Swift D.
Published: August 2014

We have designed, built, and successfully fielded a highly efficient and gated Bragg crystal spectrometer for x-ray Thomson scattering measurements on the National Ignition Facility (NIF). It utilizes a cylindrically curved Highly Oriented Pyrolytic Graphite crystal. Its spectral range of 7.4–10 keV is optimized for scattering experiments using a Zn He-α x-ray probe at 9.0 keV or Mo K-shell line emission around 18 keV in second diffraction order. The spectrometer has been designed as a diagnostic instrument manipulator-based instrument for the NIF target chamber at the Lawrence Livermore National Laboratory, USA. Here, we report on details of the spectrometer snout, its novel debris shield configuration and an in situ spectral calibration experiment with a Brass foil target, which demonstrated a spectral resolution of E/ΔE = 220 at 9.8 keV.
Optical layout and mechanical structure of polarimeter-interferometer system for Experimental Advanced Superconducting Tokamak
Authors: Zou Z. Y. , Liu H. Q. , Jie Y. X. , Ding W. X. , Brower D. L. , Wang Z. X. , Shen J. S. , An Z. H. , Yang Y. , Zeng L. , Wei X. C. , Li G. S. , Zhu X. , Lan T.
Published: August 2014

A Far-InfaRed (FIR) three-wave POlarimeter-INTerferometer (POINT) system for measurement current density profile and electron density profile is under development for the EAST tokamak. The FIR beams are transmitted from the laser room to the optical tower adjacent to EAST via ∼20 m overmoded dielectric waveguide and then divided into 5 horizontal chords. The optical arrangement was designed using ZEMAX, which provides information on the beam spot size and energy distribution throughout the optical system. ZEMAX calculations used to optimize the optical layout design are combined with the mechanical design from CATIA, providing a 3D visualization of the entire POINT system.
Atom interferometry in space: Thermal management and magnetic shielding
Authors: Milke Alexander , Kubelka-Lange André , Gürlebeck Norman , Rievers Benny , Herrmann Sven , Schuldt Thilo , Braxmaier Claus
Published: August 2014

Atom interferometry is an exciting tool to probe fundamental physics. It is considered especially apt to test the universality of free fall by using two different sorts of atoms. The increasing sensitivity required for this kind of experiment sets severe requirements on its environments, instrument control, and systematic effects. This can partially be mitigated by going to space as was proposed, for example, in the Spacetime Explorer and Quantum Equivalence Principle Space Test (STE-QUEST) mission. However, the requirements on the instrument are still very challenging. For example, the specifications of the STE-QUEST mission imply that the Feshbach coils of the atom interferometer are allowed to change their radius only by about 260 nm or 2.6 × 10−4 % due to thermal expansion although they consume an average power of 22 W. Also Earth's magnetic field has to be suppressed by a factor of 105. We show in this article that with the right design such thermal and magnetic requirements can indeed be met and that these are not an impediment for the exciting physics possible with atom interferometers in space.
Colloidosomes formed by nonpolar/polar/nonpolar nanoball amphiphiles
Authors: Chang Hung-Yu , Tu Sheng-Hung , Sheng Yu-Jane , Tsao Heng-Kwong
Published: August 2014

Fullerene-based amphiphiles are able to form bilayer vesicles in aqueous solution. In this study, the self-assembly behavior of polymer-tethered nanoballs (NBs) with nonpolar/polar/nonpolar (n-p-n′) motif in a selective solvent is investigated by dissipative particle dynamics. A model NB bears two hydrophobic polymeric arms (n′-part) tethered on an extremely hydrophobic NB (n-part) with hydrophilic patch (p-part) patterned on its surface. Dependent on the hydrophobicity and length of tethered arms, three types of aggregates are exhibited, including NB vesicle, core-shell micelle, and segmented-worm. NB vesicles are developed for a wide range of hydrophobic arm lengths. The presence of tethered arms perturbs the bilayer structure formed by NBs. The structural properties including the order parameter, membrane thickness, and area density of the inner leaflet decrease with increasing the arm length. These results indicate that for NBs with longer arms, the extent of interdigitation in the membrane rises so that the overcrowded arms in the inner corona are relaxed. The transport and mechanical properties are evaluated as well. As the arm length grows, the permeability increases significantly because the steric bulk of tethered arms loosens the packing of NBs. By contrast, the membrane tension decreases owing to the reduction of NB/solvent contacts by the polymer corona. Although fusion can reduce membrane tension, NB vesicles show strong resistance to fusion. Moreover, the size-dependent behavior observed in small liposomes is not significant for NB vesicles due to isotropic geometry of NB. Our simulation results are consistent with the experimental findings.
A simple template-based transfer method to fabricate Bradbury–Nielsen gates with uniform tension for ion mobility spectrometry
Authors: Kai Ni , Jingran Guo , Guangli Ou , Yu Lei , Quan Yu , Xiang Qian , Xiaohao Wang
Published: August 2014

A Bradbury–Nielsen gate (BNG) consists of two interleaved and electrically isolated sets of wires. It is usually used to gate or modulate ion beams. Uniformly tense wires can remain parallel, equidistant, and coplanar over a wide working temperature range, which is critical to reliable BNG performance. Hence, this study analyzes the non-uniform tension of wires wound using traditional sequential winding methods in which the elastic modulus of the metal wire is much larger than that of the insulation substrate. To address this problem, a simple and reliable template-based transfer method is developed. First, a template with large elastic modulus is used to fabricate a wire mesh with uniform tension. The mesh is then transferred to the substrate. Theoretically, this method reduces the non-uniformity of the tension in wires to less than 2%; therefore, it is used to construct a BNG with stainless steel wire, a stainless steel template, and a printed circuit board substrate. The BNG was installed in our homebuilt ion mobility spectrometer. To confirm that the performance of the BNG meets the requirements of portable ion mobility spectrometry, signal intensity and resolution (approximately 30) were experimentally determined.
Crystal growth from a supersaturated melt: Relaxation of the solid-liquid dynamic stiffness
Authors: Turci Francesco , Schilling Tanja
Published: August 2014

We discuss the growth process of a crystalline phase out of a metastable over-compressed liquid that is brought into contact with a crystalline substrate. The process is modeled by means of molecular dynamics. The particles interact via the Lennard-Jones potential and their motion is locally thermalized by Langevin dynamics. We characterize the relaxation process of the solid-liquid interface, showing that the growth speed is maximal for liquid densities above the solid coexistence density, and that the structural properties of the interface rapidly converge to equilibrium-like properties. In particular, we show that the off-equilibrium dynamic stiffness can be extracted using capillary wave theory arguments, even if the growth front moves fast compared to the typical diffusion time of the compressed liquid, and that the dynamic stiffness converges to the equilibrium stiffness in times much shorter than the diffusion time.
A vacuum microgripping tool with integrated vibration releasing capability
Authors: Rong Weibin , Fan Zenghua , Wang Lefeng , Xie Hui , Sun Lining
Published: August 2014

Pick-and-place of micro-objects is a basic task in various micromanipulation demands. Reliable releasing of micro-objects is usually disturbed due to strong scale effects. This paper focuses on a vacuum micro-gripper with vibration releasing functionality, which was designed and assembled for reliable micromanipulation tasks. Accordingly, a vibration releasing strategy of implementing a piezoelectric actuator on the vacuum microgripping tool is presented to address the releasing problem. The releasing mechanism was illustrated using a dynamic micro contact model. This model was developed via theoretical analysis, simulations and pull-off force measurement using atomic force microscopy. Micromanipulation experiments were conducted to verify the performance of the vacuum micro-gripper. The results show that, with the assistance of the vibration releasing, the vacuum microgripping tool can achieve reliable release of micro-objects. A releasing location accuracy of 4.5±0.5 μm and a successful releasing rate of around 100% (which is based on 110 trials) were achieved for manipulating polystyrene microspheres with radius of 35–100 μm.
A large class of solvable discrete-time many-body problems
Authors: Bruschi Mario , Calogero Francesco , Leyvraz François
Published: August 2014

A class of N-body problems is identified, characterized by second-order discrete-time evolution equations determining the motion in the complex z-plane of an arbitrary number N of points zn ≡ zn(ℓ), where \documentclass[12pt]{minimal}\begin{document}$\ell =0,\pm 1,\pm 2,{\kern -2.1pt}...$\end{document}ℓ=0,±1,±2,... is the discrete-time independent variable. Both these equations of motion, and the solution of their initial-value problem, only involve algebraic operations: finding the zeros of explicitly known polynomials of degree N in z, finding the eigenvectors and eigenvalues of explicitly known N × N matrices. These models feature an arbitrarily large number of arbitrary parameters (“coupling constants”).
Unusual structural properties of water within the hydration shell of hyperactive antifreeze protein
Authors: Kuffel Anna , Czapiewski Dariusz , Zielkiewicz Jan
Published: August 2014

Many hypotheses can be encountered explaining the mechanism of action of antifreeze proteins. One widespread theory postulates that the similarity of structural properties of solvation water of antifreeze proteins to ice is crucial to the antifreeze activity of these agents. In order to investigate this problem, the structural properties of solvation water of the hyperactive antifreeze protein from Choristoneura fumiferana were analyzed and compared with the properties of solvation water present at the surface of ice. The most striking observations concerned the temperature dependence of changes in water structure. In the case of solvation water of the ice-binding plane, the difference between the overall structural ordering of solvation water and bulk water diminished with increasing temperature; in the case of solvation water of the rest of the protein, the trend was opposite. In this respect, the solvation water of the ice-binding plane roughly resembled the hydration layer of ice. Simultaneously, the whole solvation shell of the protein displayed some features that are typical for solvation shells of many other proteins and are not encountered in the solvation water of ice. In the first place, this is an increase in density of water around the protein. The opposite is true for the solvation water of ice – it is less dense than bulk water. Therefore, even though the structure of solvation water of ice-binding plane and the structure of solvation water of ice seem to share some similarities, densitywise they differ.
Transition scenario of the round jet in crossflow topology at low velocity ratios
Authors: Cambonie Tristan , Aider Jean-Luc
Published: August 2014

We study experimentally a round Jet In CrossFlow (JICF) at low values of the jet-to-crossflow velocity ratio R using instantaneous and time-averaged three-dimensions three-components velocimetry. The difference between instantaneous and time-averaged swirling structures of the JICF is emphasized. Through the analysis of spatial distribution of instantaneous transverse and longitudinal vortices the main transitions of the JICF are characterized for 0.15 < R < 2.2. A new transition at very low velocity ratio is found (R < 0.3). When R is large enough (R > 1.25), the classic JICF topology is recovered. In between, a deformation of the classical JICF topology is observed consisting in a progressive disappearance of the leading-edge vortices, a bending of the jet trajectory toward the wall and thus a strengthened interaction with the boundary layer. Thanks to a state-of-the-art review on the JICF topology and using visualizations of the flow structures extracted from our experimental volumetric velocimetry measurements, this article provides a complete transition scenario of the JICF topology from the high velocity ratios to the lowest ones, and gives the topological transition threshold associated with each kind of vortex.
Dielectrophoretic sample preparation for environmental monitoring of microorganisms: Soil particle removal
Authors: Fatoyinbo Henry O. , McDonnell Martin C. , Hughes Michael P.
Published: August 2014

Detection of pathogens from environmental samples is often hampered by sensors interacting with environmental particles such as soot, pollen, or environmental dust such as soil or clay. These particles may be of similar size to the target bacterium, preventing removal by filtration, but may non-specifically bind to sensor surfaces, fouling them and causing artefactual results. In this paper, we report the selective manipulation of soil particles using an AC electrokinetic microfluidic system. Four heterogeneous soil samples (smectic clay, kaolinitic clay, peaty loam, and sandy loam) were characterised using dielectrophoresis to identify the electrical difference to a target organism. A flow-cell device was then constructed to evaluate dielectrophoretic separation of bacteria and clay in a continous flow through mode. The average separation efficiency of the system across all soil types was found to be 68.7% with a maximal separation efficiency for kaolinitic clay at 87.6%. This represents the first attempt to separate soil particles from bacteria using dielectrophoresis and indicate that the technique shows significant promise; with appropriate system optimisation, we believe that this preliminary study represents an opportunity to develop a simple yet highly effective sample processing system.
Microfluidic-based measurement of erythrocyte sedimentation rate for biophysical assessment of blood in an in vivo malaria-infected mouse
Authors: Kang Yang Jun , Ha Young-Ran , Lee Sang-Joon
Published: August 2014

This study suggests a new erythrocyte sedimentation rate (ESR) measurement method for the biophysical assessment of blood by using a microfluidic device. For an effective ESR measurement, a disposable syringe filled with blood is turned upside down and aligned at 180° with respect to gravitational direction. When the blood sample is delivered into the microfluidic device from the top position of the syringe, the hematocrit of blood flowing in the microfluidic channel decreases because the red blood cell-depleted region is increased from the top region of the syringe. The variation of hematocrit is evaluated by consecutively capturing images and conducting digital image processing technique for 10 min. The dynamic variation of ESR is quantitatively evaluated using two representative parameters, namely, time constant (λ) and ESR-area (AESR). To check the performance of the proposed method, blood samples with various ESR values are prepared by adding different concentrations of dextran solution. λ and AESR are quantitatively evaluated by using the proposed method and a conventional method, respectively. The proposed method can be used to measure ESR with superior reliability, compared with the conventional method. The proposed method can also be used to quantify ESR of blood collected from malaria-infected mouse under in vivo condition. To indirectly compare with the results obtained by the proposed method, the viscosity and velocity of the blood are measured using the microfluidic device. As a result, the biophysical properties, including ESR and viscosity of blood, are significantly influenced by the parasitemia level. These experimental demonstrations support the notion that the proposed method is capable of effectively monitoring the biophysical properties of blood.
Anisotropic fractal media by vector calculus in non-integer dimensional space
Authors: Tarasov Vasily E.
Published: August 2014

A review of different approaches to describe anisotropic fractal media is proposed. In this paper, differentiation and integration non-integer dimensional and multi-fractional spaces are considered as tools to describe anisotropic fractal materials and media. We suggest a generalization of vector calculus for non-integer dimensional space by using a product measure method. The product of fractional and non-integer dimensional spaces allows us to take into account the anisotropy of the fractal media in the framework of continuum models. The integration over non-integer-dimensional spaces is considered. In this paper differential operators of first and second orders for fractional space and non-integer dimensional space are suggested. The differential operators are defined as inverse operations to integration in spaces with non-integer dimensions. Non-integer dimensional space that is product of spaces with different dimensions allows us to give continuum models for anisotropic type of the media. The Poisson's equation for fractal medium, the Euler-Bernoulli fractal beam, and the Timoshenko beam equations for fractal material are considered as examples of application of suggested generalization of vector calculus for anisotropic fractal materials and media.
Electron temperature and density characterization using L-shell spectroscopy of laser irradiated buried iron layer targets
Authors: Shahzad M. , Tallents G. J. , Steel A. B. , Hobbs L. , Hoarty D. J. , Dunn J.
Published: August 2014

Uniform high density plasmas of different materials with properties relevant to the interior of stars and to inertial fusion can be created by laser irradiation of targets containing a buried layer of the material. Buried layer targets also enable the diagnosis of hot and thermal electron, x-ray and ion heating of targets. In this paper, L-emission spectroscopy from an iron layer (thickness 77 nm) encased in an otherwise plastic target (of thickness 240 nm–1.36 μm on the laser side) is irradiated by 0.53 μm wavelength, 2 ps duration laser pulses at irradiances of 1017–1018 Wcm−2. The relative iron L-emission from Li-like Fe XXIV to Ne-like Fe XVII is used to diagnose the plasma conditions of temperature and density in the iron layer. As the upper quantum states of the L-emission lines are in local thermodynamic equilibrium, line intensity ratios depend on both electron temperature and density, which—we show—enables the simultaneous measurement of both electron temperature and density by considering several line intensity ratios. We also show that hot electron target heating and the value of thermal flux limited heat conduction can be evaluated from the relative intensity of iron lines.
Generalized Solovev equilibrium with sheared flow of arbitrary direction and stability consideration
Authors: Kaltsas D. A. , Throumoulopoulos G. N.
Published: August 2014

A Solovev-like solution describing equilibria with field aligned incompressible flows [G. N. Throumoulopoulos and H. Tasso, Phys. Plasmas 19, 014504 (2012)] is extended to non parallel flows. The solution expressed as a superposition of Bessel functions contains an arbitrary number of free parameters which are exploited to construct a variety of configurations including ITER shaped ones. For parallel flows, application of a sufficient condition for linear stability shows that this condition is satisfied in an appreciable part of the plasma region on the high-field side mostly due to the variation of the magnetic field perpendicular to the magnetic surfaces. Also, the results indicate that depending on the shape of the Mach-function profile and the values of the free parameters the flow and flow shear may have either stabilizing or destabilizing effects.
Damping of coherent acoustic vibrations by nanosized pores in colloidal hypersonic crystals
Authors: Zhu Gaohua , Wiederrecht Gary P. , Ling Chen , Wu Songtao , Banerjee Debasish , Yano Kazuhisa
Published: August 2014

We investigated the damping of the coherent acoustic vibrations in the presence of the nanosized pores in colloidal hypersonic crystals. The colloidal crystal samples are comprised of close-packed silica or monodisperse mesoporous silica spheres, where the mesoporous silica sphere contains radially aligned uniform nanosized pores. The decay of the acoustic vibrations was monitored by using ultrafast pump-probe spectroscopy. Two types of coherent acoustic modes are observed, the propagating bulk mode and the localized surface mode. Our studies show that porous structure could have different effects on different modes of vibrations. While the bulk mode is heavily damped due to the scattering from the nanosized pores, the surface mode is much less influenced.
Anomalous magnetic behavior in nanocomposite materials of reduced graphene oxide-Ni/NiFe2O4
Authors: Kollu Pratap , Prathapani Sateesh , Varaprasadarao Eswara K. , Santosh Chella , Mallick Sudhanshu , Grace Andrews Nirmala , Bahadur D.
Published: August 2014

Magnetic Reduced Graphene Oxide-Nickel/NiFe2O4 (RGO-Ni/NF) nanocomposite has been synthesized by one pot solvothermal method. Respective phase formations and their purities in the composite are confirmed by High Resolution Transmission Electron Microscope and X Ray Diffraction, respectively. For the RGO-Ni/NF composite material finite-size effects lead to the anomalous magnetic behavior, which is corroborated in temperature and field dependent magnetization curves. Here, we are reporting the behavior of higher magnetization values for Zero Field Cooled condition to that of Field Cooled for the RGO-Ni/NF nanocomposite. Also, the observed negative and positive moments in Hysteresis loops at relatively smaller applied fields (100 Oe and 200 Oe) are explained on the basis of surface spin disorder.
Optical cavity enhanced real-time absorption spectroscopy of CO2 using laser amplitude modulation
Authors: Dong Jiahao , Lam Timothy T.-Y. , Gray Malcolm B. , Warrington Richard B. , Roberts Edward H. , Shaddock Daniel A. , McClelland David E. , Chow Jong H.
Published: August 2014

We present a spectrometer based on the cavity enhanced amplitude modulated laser absorption spectroscopy (CEAMLAS) technique for measuring molecular gas absorption. This CEAMLAS spectrometer accurately measured a CO2 absorption line at 1572.992 nm with effectively 100% measurement duty cycle. It achieved an absorption sensitivity of 5.2 × 10−9 Hz−1∕2 using a linear Fabry-Perot cavity with a modest finesse of ≈1000. We also used the spectrometer to perform preliminary measurements of the 13C/12C isotopic ratio in CO2, yielding an isotopic signature δ13C of −83±9‰ for our CO2 sample.
Neutron production from puffing deuterium in plasma focus device
Authors: Kubes P. , Paduch M. , Cikhardt J. , Kortanek J. , Batobolotova B. , Rezac K. , Klir D. , Kravarik J. , Surala W. , Zielinska E. , Scholz M. , Karpinski L. , Sadowski M. J.
Published: August 2014

The current research has continued on the PF-1000 plasma focus device at the current of 2 MA by comparison of the shots with and without injected deuterium. The increase of the total neutron yield at the level of 1010–1011 per shot was achieved after the compression of about 10 μg/cm of the deuterium from the gas-valve by about 46 μg/cm of the neon or deuterium plasma sheath. It increases five times at the decrease of the puffing deuterium mass to one-half. In shots with neon in the chamber and with puffing deuterium, a considerable decrease was confirmed of the soft X-ray emission in comparison with shots without deuterium injection. This decrease can be explained by the absence of the neon in the region of the compressed and hot plasma. The deuterium plasma from the gas-puff should then be confined in the internal structures both in the phase of implosion as well as during their formation and transformation. In shots with puffing deuterium, the evolution of instabilities in the plasma column was suppressed. The deuterium plasma has a higher conductance and better ability to form expressive and dense plasmoids and to transport the internal current in comparison with neon plasma. Neutrons were produced both at the initial phase of stagnation, as well as at a later time at the evolution of the constrictions and dense plasmoids.
Internal structure of the nanogratings generated inside bulk fused silica by ultrafast laser direct writing
Authors: Sharma S. P. , Oliveira V. , Herrero P. , Vilar R.
Published: August 2014

The aim of the present work was to characterize the internal structure of nanogratings generated inside bulk fused silica by ultrafast laser processing and to study the influence of diluted hydrofluoric acid etching on their structure. The nanogratings were inscribed at a depth of 100 μm within fused silica wafers by a direct writing method, using 1030 nm radiation wavelength and the following processing parameters: E = 5 μJ, τ = 560 fs, f = 10 kHz, and v = 100 μm/s. The results achieved show that the laser-affected regions are elongated ellipsoids with a typical major diameter of about 30 μm and a minor diameter of about 6 μm. The nanogratings within these regions are composed of alternating nanoplanes of damaged and undamaged material, with an average periodicity of 351 ± 21 nm. The damaged nanoplanes contain nanopores randomly dispersed in a material containing a large density of defects. These nanopores present a roughly bimodal size distribution with average dimensions for each class of pores 65 ± 20 × 16 ± 8 × 69 ± 16 nm3 and 367 ± 239 × 16 ± 8 × 360 ± 194 nm3, respectively. The number and size of the nanopores increases drastically when an hydrofluoric acid treatment is performed, leading to the coalescence of these voids into large planar discontinuities parallel to the nanoplanes. The preferential etching of the damaged material by the hydrofluoric acid solution, which is responsible for the pores growth and coalescence, confirms its high defect density.
Interface-modification-enhanced tunnel electroresistance in multiferroic tunnel junctions
Authors: Mao H. J. , Miao P. X. , Cong J. Z. , Song C. , Cui B. , Peng J. J. , Li F. , Wang G. Y. , Zhao Y. G. , Sun Y. , Xiao L. R. , Pan F.
Published: August 2014

We report a large tunnel electroresistance (TER) effect up to ∼104% in La0.67Sr0.33MnO3/BaTiO3/Co (LSMO/BTO/Co) multiferroic tunnel junctions (MFTJs), which couples with well-defined tunnel magnetoresistance. The large TER is related to (LaAlO3)0.3(LaSrTaO6)0.7 substrates which guarantee a high-quality LSMO/BTO interface and robust ferroelectricity in BTO. The insert of 0.5 nm-thick Pt between the Co electrode and BTO barrier further enhances the TER value to 105% and improves the endurance of the MFTJs, ascribed to the shortened screening length and reduced oxidation of BTO/Co interface. Their use would advance the process towards practical MFTJs with four resistance states.
Electron energy loss spectroscopy of gold nanoparticles on graphene
Authors: DeJarnette Drew , Roper D. Keith
Published: August 2014

Plasmon excitation decay by absorption, scattering, and hot electron transfer has been distinguished from effects induced by incident photons for gold nanoparticles on graphene monolayer using electron energy loss spectroscopy (EELS). Gold nano-ellipses were evaporated onto lithographed graphene, which was transferred onto a silicon nitride transmission electron microscopy grid. Plasmon decay from lithographed nanoparticles measured with EELS was compared in the absence and presence of the graphene monolayer. Measured decay values compared favorably with estimated radiative and non-radiative contributions to decay in the absence of graphene. Graphene significantly enhanced low-energy plasmon decay, increasing mode width 38%, but did not affect higher energy plasmon or dark mode decay. This decay beyond expected radiative and non-radiative mechanisms was attributed to hot electron transfer, and had quantum efficiency of 20%, consistent with previous reports.
High operating temperature interband cascade focal plane arrays
Authors: Tian Z.-B. , Godoy S. E. , Kim H. S. , Schuler-Sandy T. , Montoya J. A. , Krishna S.
Published: August 2014

In this paper, we report the initial demonstration of mid-infrared interband cascade (IC) photodetector focal plane arrays with multiple-stage/junction design. The merits of IC photodetectors include low noise and efficient photocarrier extraction, even for zero-bias operation. By adopting enhanced electron barrier design and a total absorber thickness of 0.7 μm, the 5-stage IC detectors show very low dark current (1.10 × 10−7 A/cm2 at −5 mV and 150 K). Even with un-optimized fabrication and standard commercial (mis-matched) read-out circuit technology, infrared images are obtained by the 320 × 256 IC focal plane array up to 180 K with f/2.3 optics. The minimum noise equivalent temperature difference of 28 mK is obtained at 120 K. These initial results indicate great potential of IC photodetectors, particularly for high operating temperature applications.
Single-layer MoS2 roughness and sliding friction quenching by interaction with atomically flat substrates
Authors: Quereda J. , Castellanos-Gomez A. , Agraït N. , Rubio-Bollinger G.
Published: August 2014

We experimentally study the surface roughness and the lateral friction force in single-layer MoS2 crystals deposited on different substrates: SiO2, mica, and hexagonal boron nitride (h-BN). Roughness and sliding friction measurements are performed by atomic force microscopy. We find a strong dependence of the MoS2 roughness on the underlying substrate material, being h-BN the substrate which better preserves the flatness of the MoS2 crystal. The lateral friction also lowers as the roughness decreases, and attains its lowest value for MoS2 flakes on h-BN substrates. However, it is still higher than for the surface of a bulk MoS2 crystal, which we attribute to the deformation of the flake due to competing tip-to-flake and flake-to-substrate interactions.
In vitro cytotoxicity assessment of a hydraulic fracturing fluid
Authors: Payne Madeleine E. , Chapman Heather F. , Cumming Janet , Leusch Frederic D. L.
Published: August 2014

Environmental context
Hydraulic fracturing fluids, used in large volumes by the coal seam gas mining industry, are potentially present in the environment either in underground formations or in mine wastewater (produced water). Previous studies of the human health and environmental effects of this practice have been limited because they use only desktop methods and have not considered combined mixture toxicity. We use a novel in vitro method for toxicity assessment, and describe the toxicity of a hydraulic fracturing fluid on a human gastrointestinal cell line.

Abstract
Hydraulic fracturing fluids are chemical mixtures used to enhance oil and gas extraction. There are concerns that fracturing fluids are hazardous and that their release into the environment – by direct injection to coal and shale formations or as residue in produced water – may have effects on ecosystems, water quality and public health. This study aimed to characterise the acute cytotoxicity of a hydraulic fracturing fluid using a human gastrointestinal cell line and, using this data, contribute to the understanding of potential human health risks posed by coal seam gas (CSG) extraction in Queensland, Australia. Previous published research on the health effects of hydraulic fracturing fluids has been limited to desktop studies of individual chemicals. As such, this study is one of the first attempts to characterise the toxicity of a hydraulic fracturing mixture using laboratory methods. The fracturing fluid was determined to be cytotoxic, with half maximal inhibitory concentrations (IC50) values across mixture variations ranging between 25 and 51mM. When used by industry, these fracturing fluids would be at concentrations of over 200mM before injection into the coal seam. A 5-fold dilution would be sufficient to reduce the toxicity of the fluids to below the detection limit of the assay. It is unlikely that human exposure would occur at these high (‘before use’) concentrations and likely that the fluids would be diluted during use. Thus, it can be inferred that the level of acute risk to human health associated with the use of these fracturing fluids is low. However, a thorough exposure assessment and additional chronic and targeted toxicity assessments are required to conclusively determine human health risks.
Linkage of inflammation and oxidative stress via release of glutathionylated peroxiredoxin-2, which acts as a danger signal
Authors: Salzano Sonia , Checconi Paola , Hanschmann Eva-Maria , Lillig Christopher Horst , Bowler Lucas D. , Chan Philippe , Vaudry David , Mengozzi Manuela , Coppo Lucia , Sacre Sandra , Atkuri Kondala R. , Sahaf Bita , Herzenberg Leonard A. , Herzenberg Leonore A. , Mullen Lisa , Ghezzi Pietro
Published: August 2014

Significance

Inflammation often complicates diseases associated with oxidative stress. This study shows that inflammatory macrophages release proteins with specific forms of cysteine oxidation to disulfides, particularly glutathionylation. Redox proteomics identified peroxiredoxin 2 (PRDX2) as a protein released in glutathionylated form by inflammation both in vivo and in vitro. Extracellular PRDX2 then triggers the production of TNF-α. These data indicate that redox-dependent mechanisms, in an oxidative cascade, can induce inflammation.
Intersubjectification and clause periphery
Authors: Traugott Elizabeth Closs
Published: August 2014

Ways of identifying subjectification and especially intersubjectification are discussed using data from the history of English no doubt and surely. These adverbs arose out of non-modal expressions and were recruited for use as epistemic adverbs and metadiscursive markers. The data are shown not to support the hypothesis that expressions at left periphery are likely to be subjective (oriented toward turn-taking and discourse coherence), those at right periphery intersubjective (oriented toward turn-giving or elicitation of response, and toward the Addressee’s stance and participation in the communicative situation.). While no doubt is subjective at both left and right periphery, surely is intersubjective at both peripheries.
Metonymy and the way we speak
Authors: Panther Klaus-Uwe , Thornburg Linda L.
Published: August 2014

In this article we investigate correlations between semantically equivalent expressions (organized in manner scales according to the formal properties of length, prosodic prominence, and grammaticalization) and their varying potential to trigger a certain metonymic interpretation. We focus on manner scales of past ability as well as semantically and logically similar expressions relating to human character traits/dispositions and external circumstances. Using the concepts ofstrength of metonymic linkandcoercion, we show that shorter, prosodically weaker and more grammaticalized members in these manner scales more strongly trigger the potentiality for actuality metonymy than their longer, prosodically stronger, and less grammaticalized counterparts.
Sociophonetics and the Indian diaspora
Authors: Mesthrie Rajend , Chevalier Alida
Published: August 2014

This chapter explores the potential of phonetic and sociophonetic research in characterising varieties of English in the Indian diaspora, using South African Indian English (SAIE) as a focal point. We first identify key phonetic features that lend themselves to such comparative study. In this regard we note that retroflexes are recessive in SAIE, aspiration shows patterns that are intermediate between Indian English (IE) and varieties like White South African English (White SAE), and interdental fricatives /ð/ and /θ/ are closer to IE, while differing in respect of aspiration. In characterising the differences between IE as usually described in the literature and SAIE, three factors are crucial: (a) the give-and-take between the English of speakers of North Indian and South Indian origins in South Africa, (b) the influence of varieties of South African English, and (c) internal sociolinguistic developments within the SAIE community relating to age, gender and class. This last aspect is illustrated in detail in the second half of the chapter via a sociophonetic study of the nurse vowel.
The politics of land registration in Ethiopia: territorialising state power in the rural milieu
Authors: Chinigò Davide
Published: August 2014

Contemporary policies of land titling and registration are central to the negotiation of the rights of access to resources and constitute a main facet of the territorialisation of the state in the rural milieu. In Ethiopia, the distribution of land use certificates started in the 1990s with the support of international donors. This paper examines land registration in rural Oromiya and discusses how it reconfigures the exercise of political authority and the peasant–state interface. The paper concludes that land registration, being legitimated through a complex discursive repertoire, strengthens the capacity of the local administrative structures to exercise political authority and thereby serves to further extend the power of the state in the rural milieu. While the question of security of tenure is strongly influenced by such hierarchical state–peasant relations, the case analysed shows that the political project behind land registration is also contested and resisted, although not openly, by the farmers.
Effects of adenylates on the circadian interaction of KaiB with the KaiC complex in the reconstituted cyanobacterial Kai protein oscillator
Authors: Goda Kazuhito , Kondo Takao , Oyama Tokitaka
Published: August 2014

Cyanobacteria are photosynthetic prokaryotes that possess circadian oscillators. Clock proteins, KaiA, KaiB, KaiC compose the central circadian oscillator, which can be reconstituted in vitro in the presence of ATP. KaiC has ATPase, autokinase, and autophosphatase enzymatic activities. These activities are modulated by protein–protein interactions among the Kai proteins. The interaction of KaiB with the KaiC complex shows a circadian rhythm in the reconstituted system. We previously developed a quantitative, real-time monitoring system for the dynamic behavior of the complex using fluorescence correlation spectroscopy. Here, we examined the effects of ATP and ADP on the rhythmic interaction of KaiB. We show that increased concentration of ATP or ADP shortened period length. Adding ADP to the Kai protein oscillation shifted its phase in a phase-dependent manner. These results provide insight into how circadian oscillation entrainment mechanism is linked to cellular metabolism.
Tts1, the fission yeast homologue of the TMEM33 family, functions in NE remodeling during mitosis
Authors: Zhang Dan , Oliferenko Snezhana
Published: August 2014

The fission yeast Schizosaccharomyces pombe undergoes “closed” mitosis in which the nuclear envelope (NE) stays intact throughout chromosome segregation. Here we show that Tts1, the fission yeast TMEM33 protein that was previously implicated in organizing the peripheral endoplasmic reticulum (ER), also functions in remodeling the NE during mitosis. Tts1 promotes insertion of spindle pole bodies (SPBs) in the NE at the onset of mitosis and modulates distribution of the nuclear pore complexes (NPCs) during mitotic NE expansion. Structural features that drive partitioning of Tts1 to the high-curvature ER domains are crucial for both aspects of its function. An amphipathic helix located at the C-terminus of Tts1 is important for ER shaping and modulating the mitotic NPC distribution. Of interest, the evolutionarily conserved residues at the luminal interface of the third transmembrane region function specifically in promoting SPB-NE insertion. Our data illuminate cellular requirements for remodeling the NE during “closed” nuclear division and provide insight into the structure and functions of the eukaryotic TMEM33 family.
Adenosine uptake is the major effector of extracellular ATP toxicity in human cervical cancer cells
Authors: Mello Paola de Andrade , Filippi-Chiela Eduardo Cremonese , Nascimento Jéssica , Beckenkamp Aline , Santana Danielle Bertodo , Kipper Franciele , Casali Emerson André , Nejar Bruno Alessandra , Paccez Juliano Domiraci , Zerbini Luiz Fernando , Wink Marcia Rosângela , Lenz Guido , Buffon Andréia
Published: August 2014

In cervical cancer, HPV infection and disruption of mechanisms involving cell growth, differentiation, and apoptosis are strictly linked with tumor progression and invasion. Tumor microenvironment is ATP and adenosine rich, suggesting a role for purinergic signaling in cancer cell growth and death. Here we investigate the effect of extracellular ATP on human cervical cancer cells. We find that extracellular ATP itself has a small cytotoxic effect, whereas adenosine formed from ATP degradation by ectonucleotidases is the main factor responsible for apoptosis induction. The level of P2×7 receptor seemed to define the main cytotoxic mechanism triggered by ATP, since ATP itself eliminated a small subpopulation of cells that express high P2×7 levels, probably through its activation. Corroborating these data, blockage or knockdown of P2×7 only slightly reduced ATP cytotoxicity. On the other hand, cell viability was almost totally recovered with dipyridamole, an adenosine transporter inhibitor. Moreover, ATP-induced apoptosis and signaling—p53 increase, AMPK activation, and PARP cleavage—as well as autophagy induction were also inhibited by dipyridamole. In addition, inhibition of adenosine conversion into AMP also blocked cell death, indicating that metabolization of intracellular adenosine originating from extracellular ATP is responsible for the main effects of the latter in human cervical cancer cells.