bluuebunny/crossref_metadata_2025 huggingface dataset:
One-dimensional particle-in-cell simulations of electrostatic Bernstein waves in plasmas with kappa velocity distributions
Authors: Abdul R. F. , Mace R. L.
Published: October 2015

Electrostatic Bernstein waves that propagate exactly perpendicularly to a static magnetic field in an electron-ion plasma are investigated using one-and-two-halves dimensional particle-in-cell simulations. An ion-to-electron mass ratio of mi/me = 100 is used, allowing sufficient separation of the electron and ion time scales while still accounting for the ion dynamics without resorting to exceptionally long simulation run times. As a consequence of the mass ratio used, both the high frequency electron Bernstein wave and the lower frequency ion Bernstein wave are resolved within a single simulation run. The simulations presented here use isotropic three-dimensional kappa velocity distributions as well as the widely used Maxwellian velocity distribution, and the results from using each of these velocity distributions are analysed and compared. The behaviour of the Bernstein waves is found to be significantly dependent on the spectral index, κ, of the kappa distribution in all frequency domains of the Bernstein waves. In both the Maxwellian and kappa cases, spectral analysis of the electric field (wave) intensities, as a function of ω and k, show very good agreement between the simulation results and the linear dispersion relation for Bernstein waves. This agreement serves to validate the simulation techniques used, as well as the theory of Bernstein waves in plasmas with a kappa velocity distribution. The intensity of the field fluctuations in the simulations containing an abundance of superthermal particles, i.e., where the plasma has a kappa velocity distribution with a low kappa index, is slightly higher compared to the simulations of plasmas with higher kappa values. The plasmas with low kappa values also exhibit a broader region in frequency space of high intensity field fluctuations.
Pressure-induced phase transition and electrical properties of thermoelectric Al-doped Mg2Si
Authors: Zhao Jianbao , Liu Zhenxian , Gordon Robert A. , Takarabe Kenichi , Reid Joel , Tse John S.
Published: October 2015

A recent study has shown the thermoelectric performance of Al-doped Mg2Si materials can be significantly enhanced at moderate pressure. To understand the cause of this phenomenon, we have performed in situ angle dispersive X-ray diffraction and infrared reflectivity measurements up to 17 GPa at room temperature. Contrary to previous experiment, using helium as a pressure transmission medium, no structural transformation was observed in pure Mg2Si. In contrast, a phase transition from cubic anti-fluorite (Fm-3m) to orthorhombic anti-cotunnite (Pnma) was observed in the Al-doped sample at 10 GPa. Infrared reflectivity measurements show the electrical conductivity increases with pressure and is further enhanced after the phase transition. The electron density of states at the Fermi level computed form density functional calculations predict a maximum thermoelectric power factor at 1.9 GPa, which is in good agreement with the experimental observation.
Modulating dual-wavelength multiple quantum wells in white light emitting diodes to suppress efficiency droop and improve color rendering index
Authors: Zhao Yukun , Yun Feng , Wang Shuai , Zheng Min , Su Xilin , Guo Maofeng , Yang Xiangrong , Liu Shuo , Ding Wen , Zhang Ye
Published: October 2015

In this paper, gallium nitride (GaN) based white light-emitting diodes (WLEDs) with modulated quantities of blue (In0.15Ga0.85N) quantum wells (QWs) and cyan QWs (In0.18Ga0.82N) in multiple QW (MQW) structures have been investigated numerically and experimentally. It is demonstrated that the optical performance of LEDs is sensitive to the quantities of cyan QWs in dual-wavelength MQW structures. Compared to the LEDs with respective 0, 4, and 8 cyan QWs (12 QWs in total), the optical performance of the sample with 6 cyan QWs is the best. The deterioration of the optical performance in the sample with less (4 pairs) cyan QWs or more (8 pairs) cyan QWs than 6 cyan QWs may be ascribed to weakened reservoir effect or more defects induced. Compared to conventional blue LEDs (12 blue QWs), the sample with 6 cyan QWs could effectively suppress the efficiency droop (the experimental droop ratio decreases from 50.3% to 39.5% at 80 A/cm2) and significantly improve the color rendering index (CRI, increases from 66.4 to 77.0) simultaneously. We attribute the droop suppression to the strengthened reservoir effect and carrier confinement of deeper QWs (higher indium composition) incorporated in the dual-wavelength MQW structures, which lead to the better hole spreading and enhanced radiative recombination. Meanwhile, the remarkable experimental CRI improvement may result from the wider full-width at half-maximum of electroluminescence spectra and higher cyan intensity in WLED chips with dual-wavelength MQW structures.
Pt-functionalized reduced graphene oxide for excellent hydrogen sensing at room temperature
Authors: Ghosh Ruma , Santra Sumita , Ray Samit Kumar , Guha Prasanta Kumar
Published: October 2015

Cost effective and faster detection of H2 has always remained a challenge. We report synthesis of reduced graphene oxide (RGO)–Pt composite and its application as highly sensitive and selective H2 sensors at room temperature. Four samples by varying the ratio of RGO and Pt were prepared to test their sensing performance. The tests were carried out in inert (N2) ambience as well as air ambience. It was observed that the RGO:Pt (1:3) 1 h reduced sample demonstrated the best H2 sensing performance in terms of sensitivity, response time, and recovery time at room temperature. Its response varied from ∼19% (200 ppm) to 57% (5000 ppm) against H2 in air ambience. Also, the response time and recovery time of the RGO:Pt (1:3) sample were found to be as fast as 65 s and 230 s against 5000 ppm, respectively, in air ambience. In N2 ambience, the RGO:Pt (1:3) sample demonstrated the best response of −97% (500 ppm), but its recovery was found to be poor. The RGO–Pt composite formation was verified by high resolution transmission electron microscopy and X-ray photoelectron spectroscopy. The detailed physics behind the sensing mechanisms have been explained and experimentally verified in this work.
Spin-flip configuration interaction singles with exact spin-projection: Theory and applications to strongly correlated systems
Authors: Tsuchimochi Takashi
Published: October 2015

Spin-flip approaches capture static correlation with the same computational scaling as the ordinary single reference methods. Here, we extend spin-flip configuration interaction singles (SFCIS) by projecting out intrinsic spin-contamination to make it spin-complete, rather than by explicitly complementing it with spin-coupled configurations. We give a general formalism of spin-projection for SFCIS, applicable to any spin states. The proposed method is viewed as a natural unification of SFCIS and spin-projected CIS to achieve a better qualitative accuracy at a low computational cost. While our wave function ansatz is more compact than previously proposed spin-complete SF approaches, it successfully offers more general static correlation beyond biradicals without sacrificing good quantum numbers. It is also shown that our method is invariant with respect to open-shell orbital rotations, due to the uniqueness of spin-projection. We will report benchmark calculations to demonstrate its qualitative performance on strongly correlated systems, including conical intersections that appear both in ground-excited and excited-excited degeneracies.
Proton chemical shift tensors determined by 3D ultrafast MAS double-quantum NMR spectroscopy
Authors: Zhang Rongchun , Mroue Kamal H. , Ramamoorthy Ayyalusamy
Published: October 2015

Proton NMR spectroscopy in the solid state has recently attracted much attention owing to the significant enhancement in spectral resolution afforded by the remarkable advances in ultrafast magic angle spinning (MAS) capabilities. In particular, proton chemical shift anisotropy (CSA) has become an important tool for obtaining specific insights into inter/intra-molecular hydrogen bonding. However, even at the highest currently feasible spinning frequencies (110–120 kHz), 1H MAS NMR spectra of rigid solids still suffer from poor resolution and severe peak overlap caused by the strong 1H–1H homonuclear dipolar couplings and narrow 1H chemical shift (CS) ranges, which render it difficult to determine the CSA of specific proton sites in the standard CSA/single-quantum (SQ) chemical shift correlation experiment. Herein, we propose a three-dimensional (3D) 1H double-quantum (DQ) chemical shift/CSA/SQ chemical shift correlation experiment to extract the CS tensors of proton sites whose signals are not well resolved along the single-quantum chemical shift dimension. As extracted from the 3D spectrum, the F1/F3 (DQ/SQ) projection provides valuable information about 1H–1H proximities, which might also reveal the hydrogen-bonding connectivities. In addition, the F2/F3 (CSA/SQ) correlation spectrum, which is similar to the regular 2D CSA/SQ correlation experiment, yields chemical shift anisotropic line shapes at different isotropic chemical shifts. More importantly, since the F2/F1 (CSA/DQ) spectrum correlates the CSA with the DQ signal induced by two neighboring proton sites, the CSA spectrum sliced at a specific DQ chemical shift position contains the CSA information of two neighboring spins indicated by the DQ chemical shift. If these two spins have different CS tensors, both tensors can be extracted by numerical fitting. We believe that this robust and elegant single-channel proton-based 3D experiment provides useful atomistic-level structural and dynamical information for a variety of solid systems that possess high proton density.
Current leakage performance of dielectric elastomers under different boundary conditions
Authors: Lu Tongqing , Shi Zhibao , Chen Zhiqiang , Huang He , Wang T. J.
Published: October 2015

In the past decade, dielectric elastomers have become promising candidates in the applications of soft electromechanical transducers due to their outstanding properties of large deformation and high energy density. Current leakage of dielectric elastomer is one of the important dissipative mechanisms affecting the energy conversion efficiency. In this work, we experimentally investigate the current leakage performance of dielectric elastomers with different boundary conditions. We find that for displacement-type boundary conditions, the transition from Ohmic conduction to non-Ohmic conduction is abrupt near the critical electric field. By comparison, for force-type boundary conditions, the current leakage density versus electric field curve is smooth and is fit well by an exponential function. The equivalent resistivity of dielectric elastomers under force-type boundary conditions is approximately an order of magnitude smaller than that under displacement-type boundary conditions. The difference is qualitatively explained by a microscopic physical model. These results will help to design and optimize dielectric elastomer transducers to improve their energy conversion efficiency.
Cooling and manipulation of a levitated nanoparticle with an optical fiber trap
Authors: Mestres Pau , Berthelot Johann , Spasenović Marko , Gieseler Jan , Novotny Lukas , Quidant Romain
Published: October 2015

Accurate delivery of small targets in high vacuum is a pivotal task in many branches of science and technology. Beyond the different strategies developed for atoms, proteins, macroscopic clusters, and pellets, the manipulation of neutral particles over macroscopic distances still poses a formidable challenge. Here, we report an approach based on a mobile optical trap operated under feedback control that enables cooling and long range 3D manipulation of a silica nanoparticle in high vacuum. We apply this technique to load a single nanoparticle into a high-finesse optical cavity through a load-lock vacuum system. We foresee our scheme to benefit the field of optomechanics with levitating nano-objects as well as ultrasensitive detection and monitoring.
Experimental determination of quantum-well lifetime effect on large-signal resonant tunneling diode switching time
Authors: Growden Tyler A. , Brown E. R. , Zhang Weidong , Droopad Ravi , Berger Paul R.
Published: October 2015

An experimental determination is presented of the effect the quantum-well lifetime has on a large-signal resonant tunneling diode (RTD) switching time. Traditional vertical In0.53Ga0.47As/AlAs RTDs were grown, fabricated, and characterized. The switching time was measured with a high-speed oscilloscope and found to be close to the sum of the calculated RC-limited 10%–90% switching time and the quantum-well quasibound-state lifetime. This method displays experimental evidence that the two intrinsic resonant-tunneling characteristic times act independently, and that the quasibound-state lifetime then serves as a quantum-limit on the large-signal speed of RTDs.
Selection and amplification of a single optical frequency comb mode for laser cooling of the strontium atoms in an optical clock
Authors: Liu Hui , Yin Mojuan , Kong Dehuan , Xu Qinfang , Zhang Shougang , Chang Hong
Published: October 2015

In this paper, we report on the active filtering and amplification of a single mode from an optical femtosecond laser comb with mode spacing of 250 MHz by optical injection of two external-cavity diode lasers operating in cascade to build a narrow linewidth laser for laser cooling of the strontium atoms in an optical lattice clock. Despite the low injection of individual comb mode of approximately 50 nW, a single comb line at 689 nm could be filtered and amplified to reach as high as 10 mW with 37 dB side mode suppression and a linewidth of 240 Hz. This method could be applied over a broad spectral band to build narrow linewidth lasers for various applications.
Realization of a broadband electromagnetic gateway at microwave frequencies
Authors: Bai Guo Dong , Yang Fan , Jiang Wei Xiang , Mei Zhong Lei , Cui Tie Jun
Published: October 2015

We propose and experimentally demonstrate a broadband illusion device—“electromagnetic gateway” at microwave frequencies. The device is first realized using crossed split-ring resonator and wire unit cells, which can provide the desirable double-negative parameters through fine geometrical designs. Taking into account the complexities in practical realization, we then simplify the original design by using only half of the unit cells. Both simulation and experimental results verify the good abilities of the simplified gateway device in broadband in microwave frequencies.
Analysis of charge transfer and recombination for the poly(3-hexylthiophene):[6,6]-phenyl C61 butyric acid methyl ester organic solar cells with iron oxide nanoparticles in various layers
Authors: Park Eung-Kyu , Kim Ji-Hwan , Cho Hyeong Jun , Lee Dong-Hoon , Kim Yong-Sang
Published: October 2015

An improved organic solar cell's performance was obtained by focusing on the effects of iron oxide (Fe2O3) nanoparticles (NPs) within the different layers of P3HT:PCBM solar cells. We investigated the recombination mechanism in organic solar cells using the current density-voltage (J-V) characteristics at various light intensities and also analyzed the electrochemical impedance. Shockley–Read–Hall (SRH) recombination, which is dependent on the trap states, surface roughness, resistance and charge transport, controls the cell efficiency. The device performance was compared by adding iron oxide nanoparticles in the active layer and Poly(3,4-ethylenedioxythiophene):poly(styrenesulfonate) (PEDOT:PSS) layer, respectively. Also the iron oxide nanoparticle layer was inserted as an interface layer between active and PEDOT:PSS layers. The solar cell without NPs showed a 2.68% power conversion efficiency while that with Fe2O3 NPs as an interface layer showed a higher power conversion efficiency of 3.83% under air mass (AM) 1.5G illumination. The device with NPs as an interface layer showed a smooth surface roughness (1.16 nm), lower charge recombination (1.06(kT/e)), and lower parasitic resistance (254 Ω cm2).
Material and device characteristics of InAs/GaAsSb sub-monolayer quantum dot solar cells
Authors: Kim Yeongho , Ban Keun-Yong , Zhang Chaomin , Honsberg Christiana B.
Published: October 2015

We have studied the material and photovoltaic characteristics of InAs/GaAsSb sub-monolayer quantum dot solar cells (QDSCs) with different Sb contents of 0%, 5%, 15%, and 20%. All QDSCs exhibit an extended external quantum efficiency (EQE) response in the wavelength range of 960–1000 nm that corresponds to sub-bandgap photon absorption. As Sb content increases from 5% to 20%, the cutoff wavelength in the EQE extends towards longer wavelength whilst the EQE in the wavelength region of 300–880 nm is lowered due to increased defect density. Compared to the QDSC (Sb 0%), an Sb incorporation of 5% enhances the short-circuit current density from 20.65 to 22.15 mA/cm2 induced by Sb surfactant effect. Since the open-circuit voltage and fill factor of the QDSC (Sb 5%) are comparable to those of the QDSC (Sb 0%), an enhancement in solar cell efficiency (10.5%) of the QDSC (Sb 5%) is observed. Further increasing Sb content to 15% and 20% results in the degradation of solar cell performance due to increased nonradiative recombination and large valence band offset in a type-II band line-up.
Ferroelectric modulation of terahertz waves with graphene/ultrathin-Si:HfO2/Si structures
Authors: Jiang Ran , Han Zuyin , Sun Weideng , Du Xianghao , Wu Zhengran , Jung Hyung-Suk
Published: October 2015

Ferroelectric-field-effect-tunable modulation of terahertz waves in graphene/Si:HfO2/Si stack structure was observed. The modulation shows distinct behaviors when the samples under different gate polarities. At a negative voltage, a transmission modulation depth up to ∼74% was present without depending on the photo illumination power, whereas, at a positive voltage, the modulation of Thz wave shows dependence on the illumination power, which is ascribed to the creation/elimination of an extra barrier in Si layer in response to the polarization in the ferroelectric Si:HfO2 layer. Considering the good compatibility of HfO2 on Si-based semiconductor process, the ferroelectricity layer of Si:HfO2 may open up an avenue for the tunable modulation of Thz wave.
Gate tunable monolayer MoS2/InP heterostructure solar cells
Authors: Lin Shisheng , Wang Peng , Li Xiaoqiang , Wu Zhiqian , Xu Zhijuan , Zhang Shengjiao , Xu Wenli
Published: October 2015

We demonstrate monolayer molybdenum disulfide (MoS2)/indium phosphide (InP) van der Waals heterostructure with remarkable photovoltaic response. Furthermore, benefiting from the atomically thin and semiconductor nature of MoS2, we have designed the gate tunable MoS2/InP heterostructure. Applied with a top gate voltage, the Fermi level of MoS2 is effectively tuned, and the barrier height at the MoS2/InP heterojunction correspondingly changes. The power conversion efficiency of MoS2/InP solar cells has reached a value of 7.1% under AM 1.5G illumination with a gate voltage of +6 V. The tunable MoS2/InP heterostructure may be promising for highly efficient solar cells.
Large magnetic field-induced work output in a NiMnGa seven-layered modulated martensite
Authors: Pagounis E. , Szczerba M. J. , Chulist R. , Laufenberg M.
Published: October 2015

We report the performance of a Ni-Mn-Ga single crystal with a seven-layered lattice modulation (14M martensite), demonstrating large actuation work output driven by an external magnetic field. A magnetic field-induced strain of 11.2%, a twinning stress of 0.64 MPa, and a magneto-crystalline anisotropy energy of 195 kJ/m3 are measured at room temperature, which exceed the best results reported in Ni-Mn-Ga 14M martensites. The produced magnetically induced work output of about 70 kJ/m3 makes the material attractive for actuator applications. Detailed XRD investigation reveals that the studied 14M martensite is stress-induced. With increasing compression stress, the stress-induced intermartensitic transformation sequence 10M → 14M → NM was demonstrated.
Effect of Na presence during CuInSe2 growth on stacking fault annihilation and electronic properties
Authors: Stange H. , Brunken S. , Hempel H. , Rodriguez-Alvarez H. , Schäfer N. , Greiner D. , Scheu A. , Lauche J. , Kaufmann C. A. , Unold T. , Abou-Ras D. , Mainz R.
Published: October 2015

While presence of Na is essential for the performance of high-efficiency Cu(In,Ga)Se2 thin film solar cells, the reasons why addition of Na by post-deposition treatment is superior to pre-deposition Na supply—particularly at low growth temperatures—are not yet fully understood. Here, we show by X-ray diffraction and electron microscopy that Na impedes annihilation of stacking faults during the Cu-poor/Cu-rich transition of low temperature 3-stage co-evaporation and prevents Cu homogeneity on a microscopic level. Lower charge carrier mobilities are found by optical pump terahertz probe spectroscopy for samples with remaining high stacking fault density, indicating a detrimental effect on electronic properties if Na is present during growth.
A significant advantage for trapped field magnet applications—A failure of the critical state model
Authors: Weinstein Roy , Parks Drew , Sawh Ravi-Persad , Carpenter Keith , Davey Kent
Published: October 2015

Ongoing research has increased achievable field in trapped field magnets (TFMs) to multi-Tesla levels. This has greatly increased the attractiveness of TFMs for applications. However, it also increases the already very difficult problem of in situ activation and reactivation of the TFMs. The pulsed zero-field-cool (ZFC) method of activation is used in most applications because it can be accomplished with much lower power and more modest equipment than field-cool activation. The critical state model (CSM) has been a reliable theoretical tool for experimental analysis and engineering design of TFMs and their applications for over a half-century. The activating field, BA, required to fully magnetize a TFM to its maximum trappable field, BT,max, using pulsed-ZFC is predicted by CSM to be R ≡ BA/BT,max ≥ 2.0. We report here experiments on R as a function of Jc, which find a monotonic decrease of R to 1.0 as Jc increases. The reduction to R = 1.0 reduces the power needed to magnetize TFMs by about an order of magnitude. This is a critical advantage for TFM applications. The results also indicate the limits of applicability of CSM, and shed light on the physics omitted from the model. The experimental results rule out heating effects and pinning center geometry as causes of the decrease in R. A possible physical cause is proposed.
Modelling the effect of actuator-like behavior in dielectric elastomer generators
Authors: Zanini P. , Rossiter J. , Homer M.
Published: October 2015

Dielectric Elastomer Generators (DEGs) have been claimed as one promising technology for renewable mechanical to electrical energy harvesting, due to their lightweight, low cost, and high energy density. Dielectric elastomers have a dual behavior, able to convert electrical energy into mechanical if charged electrostatically and to convert mechanical to electrical energy if stretched and relaxed in a cycle that exploits its capacitance change. During such energy harvesting cycles, the material needs an electrical energy bias to be able to convert mechanical work into electrical energy, which produces an actuator behavior on the DEG that results in losses and decreases its performance. In this paper, we investigate this actuation behavior and its effect on energy harvesting in the DEGs. We compare two different charging methods and show that a constant voltage method can increase the net energy harvested by 5 times, despite the unwanted actuation effect.
Management options for water-repellent soils in Australian dryland agriculture
Authors: Roper M. M. , Davies S. L. , Blackwell P. S. , Hall D. J. M. , Bakker D. M. , Jongepier R. , Ward P. R.
Published: October 2015

Water-repellent (‘non-wetting’) soils are a major constraint to agricultural production in southern and south-west Australia, affecting >10 Mha of arable sandy soils. The major symptom is dry patches of surface soil, even after substantial rainfall, directly affecting agricultural production through uneven crop and pasture germination, and reduced nutrient availability. In addition, staggered weed germination impedes effective weed control, and delayed crop and pasture germination increases the risk of wind erosion. Water repellency is caused by waxy organic compounds derived from the breakdown of organic matter mostly of plant origin. It is more prevalent in soils with a sandy surface texture; their low particle surface area : volume ratio means that a smaller amount of waxy organic compounds can effectively cover a greater proportion of the particle surface area than in a fine-textured soil. Water repellency commonly occurs in sandy duplex soils (Sodosols and Chromosols) and deep sandy soils (Tenosols) but can also occur in Calcarosols, Kurosols and Podosols that have a sandy surface texture. Severity of water repellency has intensified in some areas with the adoption of no-till farming, which leads to the accumulation of soil organic matter (and hence waxy compounds) at the soil surface. Growers have also noticed worsening repellency after ‘dry’ or early sowing when break-of-season rains have been unreliable. Management strategies for water repellency fall into three categories: (i) amelioration, the properties of surface soils are changed; (ii) mitigation, water repellency is managed to allow crop and pasture production; (iii) avoidance, severely affected or poorly producing areas are removed from annual production and sown to perennial forage. Amelioration techniques include claying, deep cultivation with tools such as rotary spaders, or one-off soil inversion with mouldboard ploughs. These techniques can be expensive, but produce substantial, long-lasting benefits. However, they carry significant environmental risks if not adopted correctly. Mitigation strategies include furrow-seeding, application of wetting agents (surfactants), no-till with stubble retention, on-row seeding, and stimulating natural microbial degradation of waxy compounds. These are much cheaper than amelioration strategies, but have smaller and sometimes inconsistent impacts on crop production. For any given farm, economic analysis suggests that small patches of water repellency might best be ameliorated, but large areas should be treated initially with mitigation strategies. Further research is required to determine the long-term impacts of cultivation treatments, seeding systems and chemical and biological amendments on the expression and management of water repellency in an agricultural context.
More famine than feast: pattern and variation in a potentially degenerating mammal fauna on Cape York Peninsula
Authors: Perry Justin J. , Vanderduys Eric P. , Kutt Alex S.
Published: October 2015

Context Global mammal populations continue to be threatened by environmental change, and recent decadal monitoring in northern Australia suggests a collapse in mammal abundance in key locations. Cape York Peninsula has globally significant natural values but there is very little published about the status and distribution of mammals in this region. Aims Following an extensive field survey we investigated two key questions: (i) what is the composition, spatial variation and change from previous regional surveys in the mid to late 1900s in the native terrestrial and arboreal mammal fauna recorded; and (ii) which landscape and site factors best predict mammal richness and abundance. Methods We sampled 202 one-hectare sites across seven locations from 2009 to 2012 in woodlands, closed forestand dune scrub and tussock grasslands. We collected landscape and site-based environmental data for each location, representing fire, weather and vegetation factors. We used generalised linear mixed models to examine the relationship between mammals and these factors. Key results Mammals were generally scarce across the sites and were more abundant and species rich in wet coastal grasslands or closed forests then tropical savanna woodlands. Fire frequency data and the surrounding vegetation complexity were consistent landscape-scale predictors of mammals; ground cover and woody complexity were significant at the site scale. Conclusions Notwithstanding interpretational constraints related to the limited evidence base of historic sampling, the mammal fauna recorded in this study for Cape York Peninsula was similar in composition to the mammal fauna described from 1948–1980 and surveys in 1985, with some species seemingly declining (e.g. Melomys burtoni, Dasyurus hallucatus, Sminthopsis virginiae) and others stable (e.g. Rattus sordidus) or more common (e.g. Rattus tunneyi); however, across all sites abundance was low, and many sites had few or no mammals. Implications In the absence of consistent long-term systematic monitoring it is difficult to determine if this survey and historical surveys represent pre-European patterns for mammals. The absence or low abundance of mammals in most sites suggest that cotemporary patterns may not represent an intact mammal fauna. Due to the equivocal nature of these findings a critical next step is to establish robust monitoring and experimental work to reveal the response of mammals to management interventions.
REVIEW: In vitro plant regeneration studies and their potential applications in Populus spp.: a review
Authors: Gaur Ayesh , Kumar Pankaj , Thakur Ajay Kumar , Srivastava Dinesh Kumar
Published: October 2015

Genus Populus comprises about 25–35 species of deciduous flowering plants in the family Salicaceae which are widely distributed in temperate climates of the Northern Hemisphere. Populus species are important resources in certain branches of industry and have a special role for the scientific study of biological and agricultural systems. The poplar is known for its remarkable significance among the commercially propagated tree species such as teak, eucalyptus, wild cherry, red wood, and radiata pine. In vitro regeneration refers to growing and multiplications of cells, tissues and organs on defined liquid/solid media under aseptic and controlled environments. In vitro clonal propagation of forest trees, due to the high multiplication rate, is an attractive alternative for rapid propagation of elite genotypes of those species that could not easily be propagated through conventional methods. Owing to their widespread uses at the industrial level and for meeting the ever-increasing global demand for biomass production and wood industry, tissue culture techniques can be exploited for rapid cloning and large-scale production of planting material of various poplar species. Recent progress in the field of plant tissue culture determined this area to be one of the most dynamic and promising for experimental biology. Much work has been carried out on in vitro plant regeneration studies in Populus spp. including direct organogenesis, indirect organogenesis and somatic embryogenesis. These reviews provide an insight for in vitro plant regeneration studies in poplar species and their potential in its improvement.
Towards typologies of urban climate and global environmental change
Authors: Creutzig Felix
Published: October 2015

The beauty of cities is that every city is different. From the homogenizing perspective of global environmental change that speaks trouble. We need an understanding of which kind of cities can contribute what kind of measures to mitigate and adapt to global environmental change. Typologies of cities offer a bridge between the idiosyncratic and the global. Bounoua et al (2015 Environ. Res. Lett.

10 084010) analyse the impact of urbanization on surface climate. We discuss their results and suggest avenues for further systematic analysis.
A classification of flows on AFD factors with faithful Connes–Takesaki modules
Authors: Shimada Koichi
Published: October 2015

We completely classify flows on approximately finite dimensional (AFD) factors with faithful Connes–Takesaki modules up to cocycle conjugacy. This is a generalization of the uniqueness of the trace-scaling flow on the AFD factor of type

I
I

∞

\mathrm {II}_\infty

, which is equivalent to the uniqueness of the AFD factor of type

I
I
I

1

\mathrm {III}_1

. In order to achieve this, we show that a flow on any AFD factor with faithful Connes–Takesaki module has the Rohlin property, which is a kind of outerness for flows introduced by Kishimoto and Kawamuro.
ℤ-graded simple rings
Authors: Bell J. , Rogalski D.
Published: October 2015

The Weyl algebra over a field

k
k

of characteristic

0
0

is a simple ring of Gelfand-Kirillov dimension 2, which has a grading by the group of integers. We classify all

Z

\mathbb {Z}

-graded simple rings of GK-dimension 2 and show that they are graded Morita equivalent to generalized Weyl algebras as defined by Bavula. More generally, we study

Z

\mathbb {Z}

-graded simple rings

A
A

of any dimension which have a graded quotient ring of the form

K
[
t
,

t

−
1

;
σ
]

K[t, t^{-1}; \sigma ]

for a field

K
K

. Under some further hypotheses, we classify all such

A
A

in terms of a new construction of simple rings which we introduce in this paper. In the important special case that

GKdim
⁡
A
=

t
r
.
d
e
g

⁡
(
K

/

k
)
+
1

\operatorname {GKdim} A = \operatorname {tr.deg}(K/k) + 1

, we show that

K
K

and

σ
\sigma

must be of a very special form. The new simple rings we define should warrant further study from the perspective of noncommutative geometry.
Comparison of Acceptability of Traditional and Novel Blood Pressure
Measurement Methods
Authors: Lindroos Annika S. , Jula Antti M. , Puukka Pauli J. , Kantola Ilkka , Salomaa Veikko , Juhanoja Eeva , Sivén Sam , Jousilahti Pekka , Niiranen Teemu J.
Published: October 2015

BACKGROUND

Blood pressure (BP) monitor technology has developed significantly over the past years with the introduction of smaller and quieter home and ambulatory monitors that can both measure BP at night. The acceptability of different BP measurement methods using modern monitors is currently unknown. The purpose of this study was to compare patients’ acceptability of traditional and novel BP measurement methods using up-to-date monitors.

METHODS

A population sample of 223 participants underwent 4 office measurements on 2 occasions, a 24-hour ambulatory monitoring and 4 home measurements on 7 consecutive days with home nighttime (home-night) measurements on 2 nights. The acceptability of each method was evaluated with a questionnaire. Analysis of variance with post hoc Bonferroni correction was used to compare mean acceptability scores.

RESULTS

Mean acceptability score, with a lower score indicating better acceptability, decreased from ambulatory (3.11±0.93) to home-night (2.74±0.81) to home (2.20±0.70) to office (1.95±0.63) measurements ( P < 0.001 for all between-method comparisons). The largest between-method differences were observed in comfort of use and disturbance of everyday activities ( P < 0.001). 73.1%, 31.8%, 1.3%, and 2.2% rated office, home, home-night, and ambulatory measurements as the most acceptable method, respectively.

CONCLUSIONS

In the general population and under a research setting, office BP measurement was the method most preferred by the participants while home measurement was the second most preferred. Home-night measurement was slightly more preferred than ambulatory monitoring. However, before home-night BP measurement can be widely promoted as an alternative method for measuring nighttime BP, more evidence of its prognostic significance is needed.
Heterogeneity and diversity of group 3 innate lymphoid cells: new cells on the block
Authors: Satoh-Takayama Naoko
Published: October 2015

Innate lymphoid cells (ILCs) are a newly identified subset of innate cells that play fundamentally crucial roles for early immune defense at mucosal and non-mucosal sites. ILCs consist of ILC1s, ILC2s and ILC3s, which each have distinct transcription factors controlling their development and function. Interestingly, each of the ILC subsets represents the innate counterparts of CD4 + helper T-cell subsets T h1 , T h2 and T h17 on the basis of transcriptional regulation. ILC1s that produce IFN-γ or TNF-α, ILC2s that produce T h2 -type cytokines mainly such as IL-5 or IL-13 and ILC3s have been recently reported and reviewed in terms of IL-22- or IL-17-producing function and cell development. However, in this relatively new field, it remains likely that additional functional and regulatory mechanisms remain to be explored. More recent findings show that ILC3s are regulated by RORγt, which plays an important role for the mucosal barrier and surface protection against pathogenic bacterial infection. ILC3s might cooperate with other cells (e.g. T cells or dendritic cells) directly or indirectly, and subsequently ILC3s have impact on tissues with prompt regulation. Especially, ILC3s in mucosal site are well known to protect the intestinal surface barrier through inducible anti-microbial peptides via IL-22. Here, I will summarize and discuss the roles, function and heterogeneity of ILC3s in mucosal tissues.
Retracted: Research Article Flavocoxid Protects Against Cadmium-Induced Disruption of the Blood-Testis Barrier and Improves Testicular Damage and Germ Cell Impairment in Mice
Authors: Minutoli Letteria , Micali Antonio , Pisani Antonina , Puzzolo Domenico , Bitto Alessandra , Rinaldi Mariagrazia , Pizzino Gabriele , Irrera Natasha , Galfo Federica , Arena Salvatore , Pallio Giovanni , Mecchio Anna , Germanà Antonino , Bruschetta Daniele , Laurà Rosaria , Magno Carlo , Marini Herbert , Squadrito Francesco , Altavilla Domenica
Published: October 2015

Cadmium (Cd) causes male infertility. There is the need to identify safe treatments counteracting this toxicity. Flavocoxid is a flavonoid that induces a balanced inhibition of cyclooxygenase (COX)-1 and COX-2 peroxidase moieties and of 5-lipoxygenase (LOX) and has efficacy in the male genitourinary system. We investigated flavocoxid effects on Cd-induced testicular toxicity in mice. Swiss mice were divided into 4 groups: 2 control groups received 0.9% NaCl (vehicle; 1 ml/kg/day) or flavocoxid (20 mg/kg/day ip); 2 groups were challenged with cadmium chloride (CdCl2; 2 mg/kg/day ip) and administered with vehicle or flavocoxid. The treatment lasted for 1 or 2 weeks. The testes were processed for biochemical and morphological studies. CdCl2 increased phosphorylated extracellular signal-regulated kinase (p-ERK) 1/2, tumor necrosis factor (TNF)-α, COX-2, 5-LOX, malondialdehyde (MDA), B-cell-lymphoma (Bcl)-2-associated X protein (Bax), follicle-stimulating hormone (FSH), luteinizing hormone (LH), transforming growth factor (TGF) -β3, decreased Bcl-2, testosterone, inhibin-B, occludin, N-Cadherin, induced structural damages in the testis and disrupted the blood-testis barrier. Many TUNEL-positive germ cells and changes in claudin-11, occludin, and N-cadherin localization were present. Flavocoxid administration reduced, in a time-dependent way, p-ERK 1/2, TNF-α, COX-2, 5-LOX, MDA, Bax, FSH, LH, TGF-β3, augmented Bcl-2, testosterone, inhibin B, occludin, N-Cadherin, and improved the structural organization of the testis and the blood-testis barrier. Few TUNEL-positive germ cells were present and a morphological retrieval of the intercellular junctions was observed. In conclusion, flavocoxid has a protective anti-inflammatory, antioxidant, and antiapoptotic function against Cd-induced toxicity in mice testis. We suggest that flavocoxid may play a relevant positive role against environmental levels of Cd, otherwise deleterious to gametogenesis and tubular integrity.
Effect of Methocarbamol on Acute Pain After Traumatic Injury
Authors: Aljuhani Ohoud , Kopp Brian J. , Patanwala Asad E.
Published: October 2015

There is interest in the use of methocarbamol as an adjunctive agent for pain control after traumatic injury. The primary objective of this study was to determine the effect of methocarbamol on pain measurements after acute injury. This was a retrospective, matched cohort study conducted at an academic medical center in the United States. Consecutive adult (age ≥18 years) patients who were admitted to the hospital between June 1, 2012 and June 30, 2013 because of a traumatic injury were evaluated. Patient cases receiving methocarbamol for at least 3 days were matched to controls that did not receive methocarbamol based on age, sex, and injury severity. The primary outcome measures of pain scores were assessed on numerical rating scale from 0 to 10 (0 = no pain; 10 = worst possible pain) and conducted during routine patient care. A total of 200 patients were included in the final cohort (100 in each group). In the overall cohort, the mean age was 49 ± 22 years, 67% were men, and mean International Classification of Disease–derived Injury Severity Score was 0.8 ± 0.1 in both groups. There was no significant association between methocarbamol use and mean pain score on day 1 [coefficient 0.09, 95% confidence interval (CI), −0.57 to 0.75, P = 0.782, model R2 = 0.43], day 2 (coefficient 0.47, 95% CI, −0.15 to 1.09, P = 0.140, model R2 = 0.42), or day 3 (coefficient 0.51, 95% CI, −0.13 to 1.16, P = 0.117, model R2 = 0.42) after injury. Methocarbamol did not improve pain control after traumatic injury during the first 3 days of hospitalization.
Air in All the Wrong Places
Authors: Hsu Benson S. , Jones-Sapienza Sarah A.
Published: October 2015

Extraluminal air can occur through a wide variety of mechanisms. Often, the free air resides in isolated regions including the thorax, the peritoneum, or the mediastinum. We present a pediatric case where there was extensive extraluminal air simultaneously within several regions, one of which has never been reported in the literature.
Outcome of Pediatric Gastroenterology Outpatients With Fever and Central Line
Authors: Alexander Thomas , Blatt Julie , Skinner Asheley Cockrell , Jhaveri Ravi , Jobson Meghan , Freeman Katherine
Published: October 2015

Objective

Although management algorithms for fever and central venous catheters (CVCs) have been implemented for pediatric oncology (PO) patients, management of pediatric outpatients with noncancer diagnoses and CVCs lacks clear protocols. The aim of the study was to assess outcomes for pediatric outpatients with gastrointestinal disorders presenting with fever and CVC.

Methods

Using a microbiology database and emergency department records, we created a database of pediatric gastroenterology (PGI) and PO outpatients with fever and a CVC who presented to our emergency department or clinics from January 2010 through December 2012. We excluded patients who had severe neutropenia (absolute neutrophil count, <500/mm3). We performed chart reviews to assess demographic and clinical characteristics.

Results

A total of 334 episodes in 144 patients were evaluated. Fifty-three percent (95% confidence interval, 38%–68%) of PGI patients had a bloodstream infection, whereas only 9% (95% confidence interval, 5%-14%) of PO patients had a bloodstream infection (P < 0.001). Among patients with a bloodstream infection, the PGI patients were more likely than the PO patients to have polymicrobial infections (46% vs 15%), gram-negative infections (57% vs 27%), and/or infection with enteric organisms (61% vs 23%). The PGI patients had higher rates of CVC removal (19% vs 4%) but no statistical difference in intensive care unit needs (11% vs 4%).

Conclusions

Pediatric gastroenterology outpatients with fever and a CVC have a high prevalence of bloodstream infection. Algorithms for management need to be subspecialty specific. Pediatric gastroenterology patients presenting to emergency departments or clinics with fever and CVC require admission for monitoring and management.
Sudden Collapse of a Preschool-Aged Child on the Playground
Authors: Scheller RoseAnn L. , Johnson Laurie H. , Caruso Michelle C. , Lorts Angela
Published: October 2015

Purpose

Primary cardiac events are rare in children. There is little information in the literature regarding the most appropriate emergency department (ED) management of this type of pediatric patient, especially with regard to medication use.

This case highlights the pediatric ED evaluation and treatment of sudden collapse in a child with an ultimate diagnosis of hypertrophic cardiomyopathy. Cardiac disorders represent 2% to 6% of cases of pediatric syncope presenting to EDs, particularly if there are previous prodromal symptoms and/or a history of exertion. Evaluation should include electrocardiogram, chest radiograph, and echocardiogram if available. Management should focus on decreasing the potential for a recurring arrhythmia while maintaining cardiac preload, which can be worsened with certain medication use.

Conclusions

Although primary cardiac events in children are rare, a high index of suspicion should be maintained especially with a history of prodromal symptoms or collapse during exertion. If cardiac etiology is suspected, deliberate management should be used to exclude a treatment that could be detrimental. This case report provides an initial assessment and recommendations for management of these patients.
Cardiac Injury After All-Terrain Vehicle Accidents in 2 Children and a Review of the Literature
Authors: Ngo Kimberly D. , Pian Phillip , Hanfland Robert , Nichols Christopher S. , Merritt Glenn R. , Campbell David , Ing Richard J.
Published: October 2015

All-terrain vehicle (ATV) accidents leading to severe morbidity and mortality are common. At our institution, 2 children presented within weeks of each other after ATV accidents. Both children required cardiac valve surgery. The surgical management of these 2 children is discussed, and the literature is reviewed. On initial patient presentation, the diagnosis of a ruptured cardiac valve or ventricular septal defect (VSD) associated with these types of accidents is often delayed. We propose that patients presenting with evidence of high-energy blunt thoracic trauma after an ATV accident should undergo an electrocardiogram, cardiac enzyme assessment, and cardiac echocardiogram as part of the initial work-up to rule out significant myocardial injury.
A Toddler With Uncontrollable Shaking After a Minor Fall
Authors: Wu Henry , Mody Ameer P.
Published: October 2015

A toddler with a closed head injury six days prior to admission, recently diagnosed with post-concussive syndrome and acute otitis media presented to our emergency department with complaint of uncontrollable shaking of the head and extremities. Physical examination demonstrated dancing movements of the eyes and truncal ataxia, concerning for the diagnosis of opsoclonus-myoclonus syndrome. Magnetic resonance imaging study was consistent with a retroperitoneal mass that was confirmed as neuroblastoma by metaiodobenzylguanidine scan and later surgical resection. We present this case, accompanied by a video of the patient, to help the emergency physician recognize this rare and often misdiagnosed syndrome.