bluuebunny/crossref_metadata_2025 huggingface dataset:
Reducing spin-torque switching current by incorporating an ultra-thin Ta layer with CoFeB free layer in magnetic tunnel junctions
Authors: Liu R. S. , Meng H. , Naik V. B. , Sim C. H. , Yap S. , Luo P.
Published: December 2014

We studied the spin torque switching in dual MgO layer based magnetic tunnel junctions (MTJs) by incorporating an ultra-thin (0.5 nm) Ta layer at the CoFeB free layer/top MgO layer interface. The Ta incorporated MTJ showed a significant reduction (∼30%) in critical switching current density (JC0 ) as compared to that of the control MTJ whilst maintaining the same tunneling magnetoresistance as well as thermal stability. The reduction of JC0 can be attributed to the perpendicular magnetic anisotropy arising from the incorporation of an ultrathin Ta layer with the MgO|CoFeB structure. This scheme of reducing JC0 without degrading other properties may contribute to the development of spin-transfer-torque magnetic random access memory for low power applications
Design of a novel passive flexure-based mechanism for microelectromechanical system optical switch assembly
Authors: Zhang Jianbin , Sun Xiantao , Chen Weihai , Chen Wenjie , Jiang Lusha
Published: December 2014

In microelectromechanical system (MEMS) optical switch assembly, the collision always exists between the optical fiber and the edges of the U-groove due to the positioning errors between them. It will cause the irreparable damage since the optical fiber and the silicon-made U-groove are usually very fragile. Typical solution is first to detect the positioning errors by the machine vision or high-resolution sensors and then to actively eliminate them with the aid of the motion of precision mechanisms. However, this method will increase the cost and complexity of the system. In this paper, we present a passive compensation method to accommodate the positioning errors. First, we study the insertion process of the optical fiber into the U-groove to analyze all possible positioning errors as well as the conditions of successful insertion. Then, a novel passive flexure-based mechanism based on the remote center of compliance concept is designed to satisfy the required insertion condition. The pseudo-rigid-body-model method is utilized to calculate the stiffness of the mechanism along the different directions, which is verified by finite element analysis (FEA). Finally, a prototype of the passive flexure-based mechanism is fabricated for performance tests. Both FEA and experimental results indicate that the designed mechanism can be used to the MEMS optical switch assembly.
Accumulated self-focusing of ultraviolet light in silica glass
Authors: Khrapko Rostislav , Lai Changyi , Casey Julie , Wood William A. , Borrelli Nicholas F.
Published: December 2014

Exposure to UV light induces structural changes in silica glass. This leads to a change in density, refractive index, optical absorption, and stress. Prolonged exposure causes catastrophic damage in the form of microchannels (extended microscopic voids), not satisfactorily explained so far. We demonstrate how microchannels are created by a plasma spark in the cores of compaction-induced waveguides. The waveguides form as a result of an accumulated self-focusing effect, directly observed by in-situ microscopy. We describe the formation of a complex, permanent 3D refractive index structure in the glass, and explain how the characteristic scales of that structure evolve during the UV exposure. While single pulse dynamic self-focusing has been extensively studied, we report a multi-pulse accumulated effect.
Dipoles in graphene have infinitely many bound states
Authors: Cuenin Jean-Claude , Siedentop Heinz
Published: December 2014

We show that in graphene, modelled by the two-dimensional Dirac operator, charge distributions with non-vanishing dipole moment have infinitely many bound states. The corresponding eigenvalues accumulate at the edges of the gap faster than any power.
Two-photon-excited fluorescence resonance energy transfer in an aqueous system of CdTe quantum dots and Rhodamine B
Authors: Li Muye , Li Fang , He Zhicong , Zhang Junpei , Han Junbo , Lu Peixiang
Published: December 2014

Two-photon excited fluorescence resonance energy transfer (FRET) between CdTe quantum dots with different emission peaks and Rhodamine B in aqueous solution are investigated both experimentally and theoretically. The photoluminescence and lifetime are measured using a time-resolved fluorescence test system. The two-photon excited FRET efficiency is found to increase as the degree of spectral overlap of the emission spectrum of CdTe and the absorption spectrum of Rhodamine B increases, which is due to the increase of Forster radius of the sample. Moreover, FRET efficiency increases when the ratio of acceptor/donor concentration increases. The two-photon excited FRET efficiency was found to reach 40%.
Strain and localization effects in InGaAs(N) quantum wells: Tuning the magnetic response
Authors: Lopes-Oliveira V. , Herval L. K. S. , Orsi Gordo V. , Cesar D. F. , de Godoy M. P. F. , Galvão Gobato Y. , Henini M. , Khatab A. , Sadeghi M. , Wang S. , Schmidbauer M.
Published: December 2014

We investigated effects of localization and strain on the optical and magneto-optical properties of diluted nitrogen III–V quantum wells theoretically and experimentally. High-resolution x-ray diffraction, photoluminescence (PL), and magneto-PL measurements under high magnetic fields up to 15 T were performed at low temperatures. Bir-Pikus Hamiltonian formalism was used to study the influence of strain, confinement, and localization effects. The circularly polarized magneto-PL was interpreted considering localization aspects in the valence band ground state. An anomalous behavior of the electron-hole pair magnetic shift was observed at low magnetic fields, ascribed to the increase in the exciton reduced mass due to the negative effective mass of the valence band ground state.
Interlaced linear-nonlinear wave propagation in a warm multicomponent plasma
Authors: Dutta Debjit , Singha Prasenjit , Sahu Biswajit
Published: December 2014

Linear and nonlinear propagations of arbitrary amplitude nonlinear structures, viz. solitons, double layers, and supersolitons are investigated in multicomponent plasma consisting of warm ions, two temperature nonthermal electrons and hot nonthermal positrons. The Sagdeev pseudopotential approach is employed to obtain the energy integral equation in such a multicomponent plasma using fluid theory. The effects of several plasma parameters on the ion acoustic solitons, double layers, and supersolitons are analyzed. It is found that the present system supports the coexistence of arbitrary amplitude positive and negative potential solitons in a certain region of parameter space in addition to compressive and rarefactive double layers. Furthermore, numerical calculations reveal that these structures may exist either in supersonic or subsonic regimes. Also, the present plasma system supports supersolitonic structure in supersonic regime.
Unusual anisotropic magnetoresistance in charge-orbital ordered Nd0.5Sr0.5MnO3 polycrystals
Authors: Yang Huali , Wang Baomin , Liu Yiwei , Yang Zhihuan , Zhu Xiaojian , Xie Yali , Zuo Zhenghu , Chen Bin , Zhan Qingfeng , Wang Junling , Li Run-Wei
Published: December 2014

Due to its potential application in magnetic recording and sensing technologies, the anisotropic magnetoresistance (AMR) effect has attracted lasting attention. Despite the long history, AMR effect has not been fully understood especially in the unconventional materials, such as perovskite manganites. Here, we report an unusual AMR effect in the charge-orbital ordered (COO) Nd0.5Sr0.5MnO3 polycrystals, which is observed when the magnetic field rotates in the plane that is perpendicular to the current (out-of-plane AMR). Despite being a polycrystalline sample where no anisotropy is expected, the resistivity shows a large irreversible drop with rotating magnetic field. A model has been proposed based on anisotropic magnetic field induced the melting of COO phase to explain the unusual out-of-plane AMR successfully. Our results demonstrate a new way for understanding the close relationship between phase separation and AMR effect in COO manganites.
A modification to the Sigmund model of ion sputtering
Authors: Mark Bradley R. , Hofsäss Hans
Published: December 2014

We modify the Sigmund model of ion sputtering so that the distribution of deposited energy is in better accord with the results of molecular dynamics simulations. For a flat target surface, the model gives a sputter yield that displays a maximum as the angle of ion incidence is increased, as observed experimentally. The model also predicts that for sufficiently high angles of incidence, the curvature dependence of the crater function tends to destabilize the solid surface.
Effect of particle size distribution on the structure, hyperfine, and magnetic properties of Ni0.5Zn0.5Fe2O4 nanopowders
Authors: Bhattacharjee Kaustav , Pati Satya P. , Das G. C. , Das D. , Chattopadhyay K. K.
Published: December 2014

Ni0.5Zn0.5Fe2O4 nano powders were synthesized by an auto combustion method and then heat treated at different temperatures in air for a fixed time. As a consequence, a distribution in particle size and strain was incorporated within the specimens, as estimated from the Rietveld refinement analysis of the powder x-ray diffraction data. The changes in the microstructure and crystal structure parameters were carefully extracted through the refinement analysis. Thermal annealing causes increment in the dispersion and mean of the size distribution. Reallocation of cations in the lattice sites occur as a consequence of the heat treatment which was manifested in their altered unit cell length (a), r.m.s. strain (⟨ε2⟩1/2), oxygen positional parameter (u), metal-oxygen bond lengths (ROA and ROB), and the band positions (ν1and ν2) in the vibrational spectroscopy. We also investigate the hyperfine and magnetic properties of the samples using different instrumental techniques (with different operating time scales) like Mössbauer spectroscopy, electron paramagnetic resonance spectroscopy, and superconducting quantum interference device magnetometry. Results show that the effect of particle size distribution was manifested in their hyperfine field distribution profile, paramagnetic resonance spectra, and magnetic anisotropy energy distribution profile. Co-existence of superparamagnetic and ferrimagnetic phase was recorded at room temperature in the samples when annealed at lower temperature. However, with increase in annealing temperature, the nature of the size distribution changes and ferrimagnetic ordering predominates for the larger size nanoparticles. Thus, the effect of particle size distribution on the structural, hyperfine, and magnetic properties of various Ni0.5Zn0.5Fe2O4 nanoparticles was investigated herein which hitherto has not been discussed in the literature.
Experimental and theoretical studies of band gap alignment in GaAs1−xBix/GaAs quantum wells
Authors: Kudrawiec R. , Kopaczek J. , Polak M. P. , Scharoch P. , Gladysiewicz M. , Misiewicz J. , Richards R. D. , Bastiman F. , David J. P. R.
Published: December 2014

Band gap alignment in GaAs1−xBix/GaAs quantum wells (QWs) was studied experimentally by photoreflectance (PR) and theoretically, ab initio, within the density functional theory in which the supercell based calculations are combined with the alchemical mixing approximation applied to a single atom in a supercell. In PR spectra, the optical transitions related to the excited states in the QW (i.e., the transition between the second heavy-hole and the second electron subband) were clearly observed in addition to the ground state QW transition and the GaAs barrier transition. This observation is clear experimental evidence that this is a type I QW with a deep quantum confinement in the conduction and valence bands. From the comparison of PR data with calculations of optical transitions in GaAs1−xBix/GaAs QW performed for various band gap alignments, the best agreement between experimental data and theoretical calculations has been found for the valence band offset of 52 ± 5%. A very similar valence band offset was obtained from ab initio calculations. These calculations show that the incorporation of Bi atoms into GaAs host modifies both the conduction and the valence band. For GaAs1−xBix with 0 < x < 0.074, the conduction band shifts lineary at a rate of ∼33 meV per % Bi, which only slightly decreases with Bi concentration. Whereas the valance band shift is clearly non-linear. Reducing initially at a rate of ∼51 meV per % Bi for low concentrations of Bi and then at a significantly reduced rate of ∼20 meV per % Bi near the end of the studied composition range. The overall reduction rate of the band gap is parabolic and the reduction rates change from ∼84 to ∼53 meV per % Bi for lower and higher Bi concentrations, respectively. The calculated shifts of valence and conduction bands give the variation of valence (conduction) band offset between GaAs1−xBix and GaAs in the range of ∼60%–40% (∼40%–60%), which is in good agreement with our conclusion derived from PR measurements.
In-situ crystallization of GeTe\GaSb phase change memory stacked films
Authors: Velea A. , Borca C. N. , Socol G. , Galca A. C. , Grolimund D. , Popescu M. , van Bokhoven J. A.
Published: December 2014

Single and double layer phase change memory structures based on GeTe and GaSb thin films were deposited by pulsed laser deposition (PLD). Their crystallization behavior was studied using in-situ synchrotron techniques. Electrical resistance vs. temperature investigations, using the four points probe method, showed transition temperatures of 138 °C and 198 °C for GeTe and GaSb single films, respectively. It was found that after GeTe crystallization in the stacked films, Ga atoms from the GaSb layer diffused in the vacancies of the GeTe crystalline structure. Therefore, the crystallization temperature of the Sb-rich GaSb layer is decreased by more than 30 °C. Furthermore, at 210 °C, the antimony excess from GaSb films crystallizes as a secondary phase. At higher annealing temperatures, the crystalline Sb phase increased on the expense of GaSb crystalline phase which was reduced. Extended X-ray absorption fine structure (EXAFS) measurements at the Ga and Ge K-edges revealed changes in their local atomic environments as a function of the annealing temperature. Simulations unveil a tetrahedral configuration in the amorphous state and octahedral configuration in the crystalline state for Ge atoms, while Ga is four-fold coordinated in both as-deposited and annealed samples.
Double Gaussian distribution of barrier height observed in densely packed GaN nanorods over Si (111) heterostructures
Authors: Mohan Lokesh , Chandan Greeshma , Mukundan Shruthi , Roul Basanta , Krupanidhi S. B.
Published: December 2014

GaN nanorods were grown by plasma assisted molecular beam epitaxy on intrinsic Si (111) substrates which were characterized by powder X-ray diffraction, field emission scanning electron microscopy, and photoluminescence. The current–voltage characteristics of the GaN nanorods on Si (111) heterojunction were obtained from 138 to 493 K which showed the inverted rectification behavior. The I-V characteristics were analyzed in terms of thermionic emission model. The temperature variation of the apparent barrier height and ideality factor along with the non-linearity of the activation energy plot indicated the presence of lateral inhomogeneities in the barrier height. The observed two temperature regimes in Richardson's plot could be well explained by assuming two separate Gaussian distribution of the barrier heights.
Applicability of post-ionization theory to laser-assisted field evaporation of magnetite
Authors: Schreiber D. K. , Chiaramonti A. N. , Gordon L. M. , Kruska K.
Published: December 2014

Analysis of the detected Fe ion charge states from laser-assisted field evaporation of magnetite (Fe3O4) reveals unexpected trends as a function of laser pulse energy that break from conventional post-ionization theory for metals. For Fe ions evaporated from magnetite, the effects of post-ionization are partially offset by the increased prevalence of direct evaporation into higher charge states with increasing laser pulse energy. Therefore, the final charge state is related to both the field strength and the laser pulse energy, despite those variables themselves being intertwined when analyzing at a constant detection rate. Comparison of data collected at different base temperatures also shows that the increased prevalence of Fe2+ at higher laser energies is possibly not a direct thermal effect. Conversely, the ratio of 16O+:(16O2+ + 16O+) is well correlated with field strength and unaffected by laser pulse energy on its own, making it a better overall indicator of the field evaporation conditions. Plotting the normalized field strength versus laser pulse energy also elucidates a non-linear dependence, in agreement with the previous observations on semiconductors, which suggests field-dependent laser absorption efficiency. Together these observations demonstrate that the field evaporation process for laser-pulsed oxides exhibits fundamental differences from metallic specimens that cannot be completely explained by post-ionization theory. Further theoretical studies, combined with detailed analytical observations, are required to understand fully the field evaporation process of non-metallic samples.
An ultrafast silicon nanoplasmonic ballistic triode
Authors: Greig S. R. , Elezzabi A. Y.
Published: December 2014

A nanoscale three terminal silicon based nanoplasmonic triode is proposed as a nanometer transistor. The device is suitable for monolithic integration with complementary-metal-oxide-semiconductor technology. Due to the highly spatially inhomogeneous, highly confined nanoplasmonic mode, electrons generated through two-photon absorption in the silicon are ponderomotively accelerated towards the copper anode producing an output current. Application of a negative grid voltage allows for control of the output current. The nanoplasmonic triode is able to achieve output current as high as 628 mA/μm on an ultrafast timescale of 150 fs in a compact footprint of 0.07 μm2. Reduction of the plasmonic field strength allows for a CMOS compatible current of 11.7 mA/μm. The results demonstrate the potential for the compact optical control of current useful for applications in high-speed, high current switching, and amplification.
Boundary condition for toroidal plasma flow imposed at the separatrix in high confinement JT-60U plasmas with edge localized modes and the physics process in pedestal structure formation
Authors: Kamiya K. , Honda M. , Urano H. , Yoshida M. , Kamada Y. , Itoh K. ,   JT-60 Team
Published: December 2014

Modulation charge eXchange recombination spectroscopy measurements with high spatial and temporal resolution have made the evaluation of the toroidal plasma flow of fully stripped carbon impurity ions (VϕC6+) in the JT-60U tokamak peripheral region (including, in particular, the separatrix) possible with a better signal-to-noise ratio. By comparing co- and counter-neutral beam injection discharges experimentally, we have identified the boundary condition of VϕC6+ and radial electric field shear (∇Er) imposed at the separatrix in high confinement (H-mode) plasmas with edge localized modes (ELMs). The VϕC6+ value at the separatrix is not fixed at zero but varies with the momentum input direction. On the other hand, the ∇Er value is nearly zero (or very weakly positive) at the separatrix. Furthermore, the edge localized mode perturbation does not appear to affect both VϕC6+ and ∇Er values at the separatrix as strongly as that in the pedestal region. The above experimental findings based on the precise edge measurements have been used to validate a theoretical model and develop a new empirical model. A better understanding of the physical process in the edge transport barrier (ETB) formation due to the sheared Er formation is also discussed.
One channel defect imaging in a reverberating medium
Authors: Rodriguez S. , Veidt M. , Castaings M. , Ducasse Eric , Deschamps M.
Published: December 2014

This letter presents an acoustic one-channel location system that takes advantage of the multiple reflections occurring in the reverberating medium under investigation. Experimental results are obtained with guided waves propagating in a bounded aluminum plate. The plate is so designed that there is no direct propagation path between the single transducer and the region of interest in the plate. In that manner, the two-dimensional image obtained in the region of interest is only based on the reverberated acoustic field measured with the single fixed transducer. The method is based on the application of topological optimization methods to wave-based location problems and on a preliminary calibration of the whole system. This calibration mainly consists in measuring the impulse response of the transducer in the region of interest before any object or defect is present. The calibration is here performed with a Laser Doppler velocimeter. The experimental results obtained with this one-channel topological imaging method show accurate location of a single small defect and of multiple small defects, with a resolving power below the wavelength.
Stable finite element method of eight-band k·p model without spurious solutions and numerical study of interfaces in heterostructures
Authors: Ma Xunpeng , Li Kangwen , Zhang Zuyin , Jiang Yu , Xu Yun , Song Guofeng
Published: December 2014

A Lagrange-Hermite finite element method for the eight-band k·p model is developed. We demonstrate that besides the incompletion of k·p basis functions, the ill representation of first-order derivatives can also bend the conduction band structure down and lead to the highly oscillatory solutions. Our method simultaneously solves these two problems and achieves robust stability and high accuracy in real-space numerical calculation. The more physical asymmetric operator ordering is employed and the connection problem in abrupt interface is resolved by using an approximately abrupt interface. The situation of smooth interface used to explain the discrepancies between experiment and simulation of abrupt interface is also calculated by our method, and the result suggests that the influence of the interface smoothing should be considered in the short period superlattices or quantum structures of the narrow well.
Grain-size dependent demagnetizing factors in permanent magnets
Authors: Bance S. , Seebacher B. , Schrefl T. , Exl L. , Winklhofer M. , Hrkac G. , Zimanyi G. , Shoji T. , Yano M. , Sakuma N. , Ito M. , Kato A. , Manabe A.
Published: December 2014

The coercive field of permanent magnets decreases with increasing grain size. The grain size dependence of coercivity is explained by a size dependent demagnetizing factor. In Dy free Nd2Fe14B magnets, the size dependent demagnetizing factor ranges from 0.2 for a grain size of 55 nm to 1.22 for a grain size of 8300 nm. The comparison of experimental data with micromagnetic simulations suggests that the grain size dependence of the coercive field in hard magnets is due to the non-uniform magnetostatic field in polyhedral grains.
Potential variation around grain boundaries in BaSi2 films grown on multicrystalline silicon evaluated using Kelvin probe force microscopy
Authors: Baba Masakazu , Hara Kosuke O. , Tsukahara Daichi , Toko Kaoru , Usami Noritaka , Sekiguchi Takashi , Suemasu Takashi
Published: December 2014

Potential variations across the grain boundaries (GBs) in a 100 nm thick undoped n-BaSi2 film on a cast-grown multicrystalline Si (mc-Si) substrate are evaluated using Kelvin probe force microscopy (KFM). The θ-2θ X-ray diffraction pattern reveals diffraction peaks, such as (201), (301), (410), and (411) of BaSi2. Local-area electron backscatter diffraction reveals that the a-axis of BaSi2 is tilted slightly from the surface normal, depending on the local crystal plane of the mc-Si. KFM measurements show that the potentials are not significantly disordered in the grown BaSi2, even around the GBs of mc-Si. The potentials are higher at GBs of BaSi2 around Si GBs that are formed by grains with a Si(111) face and those with faces that deviate slightly from Si(111). Thus, downward band bending occurs at these BaSi2 GBs. Minority carriers (holes) undergo a repelling force near the GBs, which may suppress recombination as in the case of undoped n-BaSi2 epitaxial films on a single crystal Si(111) substrate. The barrier height for hole transport across the GBs varies in the range from 10 to 55 meV. The potentials are also higher at the BaSi2 GBs grown around Si GBs composed of grains with Si(001) and Si(111) faces. The barrier height for hole transport ranges from 5 to 55 meV. These results indicate that BaSi2 GBs formed on (111)-dominant Si surfaces do not have a negative influence on the minority-carrier properties, and thus BaSi2 formed on underlayers, such as (111)-oriented Si or Ge and on (111)-oriented mc-Si, can be utilized as a solar cell active layer.
Arc spot grouping: An entanglement of arc spot cells
Authors: Kajita Shin , Hwangbo Dogyun , Ohno Noriyasu , Tsventoukh Mikhail M. , Barengolts Sergey A.
Published: December 2014

In recent experiments, clear transitions in velocity and trail width of an arc spot initiated on nanostructured tungsten were observed on the boundary of the thick and thin nanostructured layer regions. The velocity of arc spot was significantly decreased on the thick nanostructured region. It was suggested that the grouping decreased the velocity of arc spot. In this study, we try to explain the phenomena using a simple random walk model that has properties of directionality and self-avoidance. And grouping feature was added by installing an attractive force between spot cells with dealing with multi-spots. It was revealed that an entanglement of arc spot cells decreased the spot velocity, and spot cells tend to stamp at the same location many times.
Time required for a sphere to fall through a funnel
Authors: Sridharan J. , Altschul B. , Crittenden S.
Published: December 2014

We experimentally test a recently proposed theory of the behavior of a single frictional, inelastic, spherical particle falling under gravity through a symmetric funnel. We find that, while many qualitative results of the theory are supported by the data, the quantitative behavior of a real sphere falling through a real funnel differs from the predictions. The behavior above a 45∘ funnel angle, the duration, and the dependence of the duration on the initial horizontal position all show significant deviations from the predicted results. In particular, for drop positions near the gap, the duration of the fall is often significantly less than predicted for 50∘ and 60∘ funnel angles; and at a 60∘ funnel angle, where the data best matches the model, the R2 goodness of fit is only 0.27. The fit can be significantly improved for 60∘ funnel angle by relaxing the most stringent approximation of the theory, which asserts that the transition from slipping to rolling is governed by a single constant parameter, β, independent of impact speed and angle. We conclude that, although the theory captures most of the key features of the dynamics of a ball falling through a funnel, it does not do so with quantitative accuracy, indicating that for commonly encountered balls and drop heights, a more realistic model of particle collisions is required.
Alloy inhomogeneity and carrier localization in AlGaN sections and AlGaN/AlN nanodisks in nanowires with 240–350 nm emission
Authors: Himwas C. , den Hertog M. , Dang Le Si , Monroy E. , Songmuang R.
Published: December 2014

We present structural and optical studies of AlGaN sections and AlGaN/AlN nanodisks (NDs) in nanowires grown by plasma-assisted molecular beam epitaxy. The Al-Ga intermixing at Al(Ga)N/GaN interfaces and the chemical inhomogeneity in AlGaN NDs evidenced by scanning transmission electron microscopy are attributed to the strain relaxation process. This interpretation is supported by the three-dimensional strain distribution calculated by minimizing the elastic energy in the structure. The alloy inhomogeneity increases with the Al content, leading to enhanced carrier localization signatures in the luminescence characteristics, i.e., red shift of the emission, s-shaped temperature dependence, and linewidth broadening. Despite these effects, the emission energy of AlGaN/AlN NDs can be tuned in the 240–350 nm range with internal quantum efficiencies around 30%.
Potential of the application of epigenetics in animal production
Authors: Gotoh Takafumi
Published: December 2014

Our many current environmental challenges, including worldwide abnormal weather, global warming, and pollution, necessitate a new and innovative strategy for animal production for the next generation. This strategy should incorporate not only higher-efficiency production, but also advanced biological concepts and multi-functional agricultural techniques, into environmentally friendly systems. Recent research has discovered a unique phenomenon referred to as ‘foetal and neonatal programming’, which is based on ‘the developmental origins of health and disease (DOHaD)’ concept. These studies have shown that alterations in foetal and early postnatal nutrition and endocrine status may result in developmental adaptations that permanently change the structure, physiology and metabolism of affected animals during adult life. Ruminants fill an important ecological niche that capitalises on the symbiotic relationship between fibre-fermenting ruminal microbes and the mammalian demand for usable nutrients. The timing of the perturbation in maternal nutrient availability plays an important role in determining the effect that the foetal and neonatal programming will have on the developing placenta or foetus and offspring performance. Developmental programming through nutritional manipulations may help the ruminant, as an effective grass–protein converter, fulfil its production potential.
Lactosucrose attenuates intestinal inflammation by promoting Th2 cytokine production and enhancing CD86 expression in colitic rats
Authors: Zhou Yan , Ruan Zheng , Zhou Xiaoli , Huang Xiaoliu , Li Hua , Wang Ling , Zhang Cui , Deng Zeyuan , Wu Guoyao , Yin Yulong
Published: December 2014

Some oligosaccharides have immunoregulatory and anti-inflammatory functions in the intestine. This study investigated the immunoregulatory effect of lactosucrose (LS) on 2,4,6-trinitrobenzenesulfonic acid (TNBS)-induced colitic rats. Alkaline phosphatase activity was increased but myeloperoxidase activity was decreased in the LS-TNBS group, as compared with the TNBS group (colitis rats without receiving LS). LS supplementation stimulated IL-4 and IL-10 production, while up-regulating CD86 expression in dendritic cells. LS supplementation reduced the ratio of CD80/CD86 and the ratio of IFN-γ/IL-4 compared to the TNBS group. Moreover, IFN-γ was significantly correlated with CD80 (r = 0.764, p < 0.01), whereas IL-4 was significantly correlated with CD86 (r = 0.489, p < 0.05). These results indicated that LS attenuated colitis by promoting the production of Th2-type cytokines and rebalancing the ratio of Th1/Th2 and that enhanced IL-4 production is correlated with enhanced CD86 expression in the gut. Therefore, LS is a functional food for patients with inflammatory bowel disease.
β-Lactamase inhibition by avibactam in Mycobacterium abscessus
Authors: Dubée Vincent , Bernut Audrey , Cortes Mélanie , Lesne Tiffany , Dorchene Delphine , Lefebvre Anne-Laure , Hugonnet Jean-Emmanuel , Gutmann Laurent , Mainardi Jean-Luc , Herrmann Jean-Louis , Gaillard Jean-Louis , Kremer Laurent , Arthur Michel
Published: December 2014

Objectives

Two β-lactams, cefoxitin and imipenem, are part of the reference treatment for pulmonary infections with Mycobacterium abscessus. M. abscessus has recently been shown to produce a broad-spectrum β-lactamase, BlaMab, indicating that the combination of β-lactams with a BlaMab inhibitor may improve treatment efficacy. The objectives of this study were to evaluate the impact of BlaMab production on the efficacy of β-lactams in vitro and to assess the benefit of BlaMab inhibition on the activity of β-lactams intracellularly and in an animal model.

Methods

We analysed the mechanism and kinetics of BlaMab inactivation by avibactam, a non-β-lactam β-lactamase inhibitor currently in Phase III of development, in combination with ceftazidime for the treatment of serious infections due to Gram-negative bacteria. We then deleted the gene encoding BlaMab to assess the extent of BlaMab inhibition by avibactam based on a comparison of the impact of chemical and genetic inactivation. Finally, the efficacy of amoxicillin in combination with avibactam was evaluated in cultured human macrophages and in a zebrafish model of M. abscessus infection.

Results

We showed that avibactam efficiently inactivated BlaMab via the reversible formation of a covalent adduct. An inhibition of BlaMab by avibactam was observed in both infected macrophages and zebrafish.

Conclusions

Our data identify avibactam as the first efficient inhibitor of BlaMab and strongly suggest that β-lactamase inhibition should be evaluated to provide improved therapeutic options for M. abscessus infections.
Characterization of cement float buoyancy in the stalked barnacle
Dosima fascicularis
(Crustacea, Cirripedia)
Authors: Zheden Vanessa , Kovalev Alexander , Gorb Stanislav N. , Klepal Waltraud
Published: December 2014

Dosima fascicularis
is the only barnacle which can drift autonomously at the water surface with a foam-like cement float. The cement secreted by the animal contains numerous gas-filled cells of different size. When several individuals share one float, their size and not their number is crucial for the production of both volume and mass of the float. The gas content within the cells of the foam gives positive static buoyancy to the whole float. The volume of the float, the gas volume and the positive static buoyancy are positively correlated. The density of the cement float without gas is greater than that of seawater. This study shows that the secreted cement consists of more than 90% water and the gas volume is on average 18.5%. Our experiments demonstrate that the intact foam-like cement float is sealed to the surrounding water.
Cyanobacterial distributions along a physico‐chemical gradient in the Northeastern Pacific Ocean
Authors: Sudek Sebastian , Everroad R. Craig , Gehman Alyssa‐Lois M. , Smith Jason M. , Poirier Camille L. , Chavez Francisco P. , Worden Alexandra Z.
Published: December 2014

The cyanobacteria Prochlorococcus and Synechococcus are important marine primary producers. We explored their distributions and covariance along a physico‐chemical gradient from coastal to open ocean waters in the Northeastern Pacific Ocean. An inter‐annual pattern was delineated in the dynamic transition zone where upwelled and eastern boundary current waters mix, and two new Synechococcus clades, Eastern Pacific Clade (EPC) 1 and EPC2, were identified. By applying state‐of‐the‐art phylogenetic analysis tools to bar‐coded 16S amplicon datasets, we observed higher abundance of Prochlorococcus high‐light I (HLI) and low‐light I (LLI) in years when more oligotrophic water intruded farther inshore, while under stronger upwelling Synechococcus I and IV dominated. However, contributions of some cyanobacterial clades were proportionally relatively constant, e.g. Synechococcus EPC2. In addition to supporting observations that Prochlorococcus LLI thrive at higher irradiances than other LL taxa, the results suggest LLI tolerate lower temperatures than previously reported. The phylogenetic precision of our 16S rRNA gene analytical approach and depth of bar‐coded sequencing also facilitated detection of clades at low abundance in unexpected places. These include Prochlorococcus at the coast and Cyanobium‐related sequences offshore, although it remains unclear whether these came from resident or potentially advected cells. Our study enhances understanding of cyanobacterial distributions in an ecologically important eastern boundary system.
Assessing the Impact of Blended Learning on Student Performance
Authors: Kwak Do Won , Menezes Flavio M. , Sherwood Carl
Published: December 2014

This paper assesses quantitatively the impact on student performance of a blended learning experiment within a large undergraduate first‐year course in statistics for business and economics students. We employ a difference‐in‐differences method, which controls for differences in student characteristics and course delivery method, to evaluate the impact of blended learning on student performance. Our results suggest that the impact of blended learning on student performance depends on whether the effect of blended learning is cumulative or not. Blended learning has no impact on student performance if learning is non‐cumulative and only affects the performance on the quizzes associated with the material covered by blended learning. However, if learning is cumulative and impacts the performance for the whole course, then our results strongly suggest a strong, negative effect. Taken as a whole, these results provide a possible explanation for why most of the existing studies focusing on short online courses have obtained neutral or even positive results while nearly all the studies focusing on semester‐length course tend to observe negative impacts from online learning.
The Contribution of Australian Academia to the World's Best Economics Research: 2001 to 2010
Authors: Neri Frank , Rodgers Joan
Published: December 2014

We investigate the output of top economics research by Australian academics from 2001 to 2010. By constructing a unique database of 26,219 publications in 45 top journals, we compare Australia's output internationally, determine whether Australia's output increased, and rank Australian universities based on their output. We find that Australia's output, in absolute and relative terms, and controlling for differences in page size and journal quality, increased and, on a per capita basis, is converging to the levels of the most research‐intensive countries. Finally, we find that the historical dominance of the top four universities is diminishing.
Current role of rituximab in systemic lupus erythematosus
Authors: Mok Chi Chiu
Published: December 2014

Systemic lupus erythematosus (SLE) is a systemic autoimmune disease characterized by periods of flares and remission, resulting in organ damage over time caused by persistent disease activity and treatment‐related complications. Conventional therapies are not ideal in terms of efficacy and safety. Novel biological therapies are being developed to enhance therapeutic efficacy, minimize disease exacerbation and reduce toxicities. As dysregulation of B cells is the hallmark of SLE, B‐cell targeted therapies are the focus of recent clinical research. Rituximab, a chimeric anti‐CD20 monoclonal antibody, has been used with success in recalcitrant lupus manifestations. However, randomized controlled trials have failed to reveal its benefit in renal and non‐renal SLE when combined with conventional immunosuppressive protocols. Although heterogeneity of SLE manifestations, pitfalls in study design and the limitations of the assessment tools for various clinical end points may have contributed to the discouraging results, rituximab remains an option in patients who are refractory or intolerant to conventional therapies. Recently, a regimen consisting of rituximab and mycophenolate mofetil without oral corticosteroids was reported to be effective in lupus nephritis. While the efficacy of this regimen has to be confirmed, future controlled trials should focus on the efficacy of rituximab in refractory lupus manifestations and its synergistic effect with other immunosuppressive agents such as cyclophosphamide. In short‐term randomized controlled trials, a non‐significant increase in serious adverse events was observed in SLE patients treated with rituximab. Long‐term safety data of rituximab in SLE, in particular the incidence of hypogammaglobulinemia and serious/opportunistic infections, have to be continuously surveyed.
Differential regulation of mGlu5R and ΜOPr by priming‐ and cue‐induced reinstatement of cocaine‐seeking behaviour in mice
Authors: Georgiou Polymnia , Zanos Panos , Ehteramyan Mazdak , Hourani Susanna , Kitchen Ian , Maldonado Rafael , Bailey Alexis
Published: December 2014

The key problem for the treatment of drug addiction is relapse to drug use after abstinence that can be triggered by drug‐associated cues, re‐exposure to the drug itself and stress. Understanding the neurobiological mechanisms underlying relapse is essential in order to develop effective pharmacotherapies for its prevention. Given the evidence implicating the metabotropic glutamate receptor 5 (mGlu5R), μ‐opioid receptor (MOPr), κ‐opioid receptor (ΚOPr) and oxytocin receptor (OTR) systems in cocaine addiction and relapse, our aim was to assess the modulation of these receptors using a mouse model of cue‐ and priming‐induced reinstatement of cocaine seeking. Male mice were trained to self‐administer cocaine (1 mg/kg/infusion, i.v.) and were randomized into different groups: (1) cocaine self‐administration; (2) cocaine extinction; (3) cocaine‐primed (10 mg/kg i.p.); or (4) cue‐induced reinstatement of cocaine seeking. Mice undergoing the same protocols but receiving saline instead of cocaine were used as controls. Quantitative autoradiography of mGlu5R, MOPr, KOPr and OTR showed a persistent cocaine‐induced upregulation of the mGlu5R and OTR in the lateral septum and central amygdala, respectively. Moreover, a downregulation of mGlu5R and MOPr was observed in the basolateral amygdala and striatum, respectively. Further, we showed that priming‐ but not cue‐induced reinstatement upregulates mGlu5R and MOPr binding in the nucleus accumbens core and basolateral amygdala, respectively, while cue‐ but not priming‐induced reinstatement downregulates MOPr binding in caudate putamen and nucleus accumbens core. This is the first study to provide direct evidence of reinstatement‐induced receptor alterations that are likely to contribute to the neurobiological mechanisms underpinning relapse to cocaine seeking.
Can Incarcerated Felons Be (Re)integrated into the Political System? Results from a Field Experiment
Authors: Gerber Alan S. , Huber Gregory A. , Meredith Marc , Biggers Daniel R. , Hendry David J.
Published: December 2014

How does America's high rate of incarceration shape political participation? Few studies have examined the direct effects of incarceration on patterns of political engagement. Answering this question is particularly relevant for the 93% of formerly incarcerated individuals who are eligible to vote. Drawing on new administrative data from Connecticut, we present evidence from a field experiment showing that a simple informational outreach campaign to released felons can recover a large proportion of the reduction in participation observed following incarceration. The treatment effect estimates imply that efforts to reintegrate released felons into the political process can substantially reduce the participatory consequences of incarceration.
The prevalence of NAFLD and NASH among patients with psoriasis in a tertiary care dermatology and rheumatology clinic
Authors: Roberts K. K. , Cochet A. E. , Lamb P. B. , Brown P. J. , Battafarano D. F. , Brunt E. M. , Harrison S. A.
Published: December 2014

Background

Psoriasis has been linked to metabolic syndrome and non‐alcoholic fatty liver disease (NAFLD). Data suggest that the prevalence of NAFLD is increased in patients with psoriasis. The aim of this study was to determine the prevalence and severity of NAFLD in this patient population.

Aim

To determine the prevalence of both NAFLD and non‐alcoholic steatohepatitis (NASH) in patients with psoriasis.

Methods

Patients between the ages of 18 and 70 years with a diagnosis of psoriasis or psoriatic arthritis and followed by either the Dermatology or Rheumatology Division within the Department of Medicine at San Antonio Military Medical Center were considered for enrollment. Each patient completed a questionnaire, underwent a thorough skin evaluation, and had a right upper quadrant ultrasound and fasting blood work. If the liver enzymes were elevated or fatty liver detected on imaging, percutaneous liver biopsy was recommended.

Results

One hundred and twenty‐nine patients were enrolled and 103 completed all necessary studies. The participants were predominantly middle aged (52.7 ± 12) and overweight or obese (average BMI 30.1 ± 5.9, range: 19.8–52.5 kg/m2). 53% (n = 54) were male while 15% (n = 15) of participants identified themselves as being a diabetic. The overall prevalence of NAFLD was 47%. The overall prevalence of NASH was 22% in those who underwent biopsy.

Conclusions

Non‐alcoholic fatty liver disease is very common among our cohort of patients with psoriasis, occurring in roughly 47% of patients. The more progressive form of the disease, NASH, is found in approximately one in five patients. Health care providers should be mindful of this association given the high prevalence of both NAFLD and NASH in this cohort of patients.
Illicit mint and unregulated vendors: constructing illegality in French public spaces
Authors: Tchoukaleyska Roza
Published: December 2014

Focusing on street‐side vending of fresh mint and herbs in the French city of Montpellier, this paper considers the difference between illegal and informal vending, and the regulatory mechanisms deployed by municipal and police actors in the push to eradicate illegality. Drawing on municipal archives from the late 1990s, and interviews and city documents from the 2000s, I examine the relationship between regularised market stall holders and those selling goods outside assigned vending spaces, with a particular interest in how these two groups interact, and the instances in which police and market officials are called. Through a rapidly escalating campaign to fight illegality, green fresh mint is coded as an illicit product and the individuals who sell it are targeted as dangerous criminal elements.
Effect of probiotic bacteria‐fermented medicinal plants (Gynura procumbens, Rehmannia glutinosa, Scutellaria baicalensis) as performance enhancers in growing pigs
Authors: Jeong Jin Suk , Kim In Ho
Published: December 2014

This study was conducted to investigate the effect of dietary supplementation of mixed fermented medicinal plants (FMP) obtained from exudates of Gynura procumbens, Rehmannia glutinosa and Scutellaria baicalensis fermented with Lactobacillus plantarum, Saccharomyces cerevisiae and Bacillus licheniformis, respectively, on growth performance in growing pigs in order to assess the feasibility of using FMP as an alternative to antibiotic growth promoters (AGP), such as tiamulin. A total of 150 growing pigs (body wieght 25.50 ± 2.50 kg) were used in a 6 weeks experiment and randomly divided into five groups with six replicates of five growing pigs each. The treatments were NC (basal diet), basal diet with 33 ppm tiamulin (PC), basal diet with FMP 0.05% (FMP 0.05), basal diet with FMP 0.1% (FMP 0.1) and basal diet with FMP 0.2% (FMP 0.2). Overall, body weight gain, feed conversion rate, the digestibility of dry matter and gross energy, noxious gas emission all improved with FMP supplementation as compared to NC. Taken together, these results suggest the feasibility of using FMP as an alternative to AGP for enhancing the growth performance, nutrient digestibility and excreta noxious gas emission of growing pigs.