bluuebunny/crossref_metadata_2025 huggingface dataset:
Highly stable GeOx@C core–shell fibrous anodes for improved capacity in lithium-ion batteries
Authors: Li Meng , Zhou Dan , Song Wei-Li , Li Xiaogang , Fan Li-Zhen
Published: August 2015

We demonstrate a facile fabrication in which encapsulation of GeOx nanoparticles into hollow carbon shells is achieved through co-axial electrospinning. The resultant GeOx@C core–shell fiber electrode exhibits excellent lithium storage performance, with stable reversible capacity and excellent rate capability.
Ammonia borane confined by nitrogen-containing carbon nanotubes: enhanced dehydrogenation properties originating from synergetic catalysis and nanoconfinement
Authors: Zhang Lijun , Xia Guanglin , Ge Yu , Wang Caiyun , Guo Zaiping , Li Xingguo , Yu Xuebin
Published: August 2015

AB@PPy composites synthesized by a solution method show favorable dehydrogenation properties.
Engineering nanostructured electrode materials for high performance sodium ion batteries: a case study of a 3D porous interconnected WS2/C nanocomposite
Authors: Zhu Changbao , Kopold Peter , Li Weihan , van Aken Peter A. , Maier Joachim , Yu Yan
Published: August 2015

A 3D porous interconnected WS2/C nanocomposite is prepared by an ESD technique, which shows great potential for sodium anode materials.
Asymmetrically twisted anthracene derivatives as highly efficient deep-blue emitters for organic light-emitting diodes
Authors: He Chuanyou , Guo Haoqing , Peng Qiming , Dong Shengzhi , Li Feng
Published: August 2015

Two anthracene derivatives with asymmetrically twisted molecular structure achieved high thermal stability and high-efficiency deep-blue emissions.
Color tuning in inverted blue light-emitting diodes based on a polyfluorene derivative by adjusting the thickness of the light-emitting layer
Authors: Xu Jin , Yu Lei , Hu Liwen , He Ruifeng , Yang Wei , Peng Junbiao , Cao Yong
Published: August 2015

The EL spectra possessed high adjustability with the variation of thickness of the emissive layer in the IPLEDs.
Modeling of microplasmas from GHz to THz
Authors: Gregório J. , Hoskinson A. R. , Hopwood J.
Published: August 2015

We present a study of atmospheric-pressure microdischarges sustained over a wide range of continuous excitation frequencies. A fluid model is used to describe the spatial and temporal evolution of the plasma properties within a 200 μm discharge gap. At 0.5 GHz, the behavior is similar to a typical rf collisional discharge. As frequency increases at constant power density, we observe a decrease in the discharge voltage from greater than 100 V to less than 10 V. A minimum of the voltage amplitude is attained when electron temporal inertia delays the discharge current to be in phase with the applied voltage. Above this frequency, the plasma develops resonant regions where the excitation frequency equals the local plasma frequency. In these volumes, the instantaneous quasi-neutrality is perturbed and intense internal currents emerge ensuring a low voltage operation range. This enhanced plasma heating mechanism vanishes when the excitation frequency is larger than the local plasma frequency everywhere in the plasma volume. For a typical peak electron density of 5×1020 m−3, this condition corresponds to ∼0.2 THz. Beyond the plasma frequency, the discharge performs like a low loss dielectric and an increasingly large voltage is necessary to preserve a constant absorbed power.
Analysis of edge threading dislocations b→=12〈110〉 in three dimensional Ge crystals grown on (001)-Si substrates
Authors: Arroyo Rojas Dasilva Y. , Rossell M. D. , Keller D. , Gröning P. , Isa F. , Kreiliger T. , von Känel H. , Isella G. , Erni R.
Published: August 2015

Threading dislocations (TDs) in germanium (Ge) crystals epitaxially grown on a patterned (001)-silicon (Si) substrate are investigated using transmission electron microscopy (TEM) techniques. Analysis of dislocations performed on the Ge crystals reveals 60° and edge TDs with Burgers vector b→=12〈110〉. High-angle annular dark-field scanning TEM (HAADF-STEM) is used to observe the core of the edge TDs at atomic scale. Pairs of TDs with b→=12〈110〉 are present in the material running parallel at small distances between them (0.5–1.5 nm). The observation of such parallel dislocation pairs in Ge has not been documented before. The interaction between the edge dislocation pairs is obtained experimentally from the high-resolution HAADF-STEM images by applying geometrical phase analysis. The experimental strain maps are compared to analytical calculations based on the anisotropic elastic theory demonstrating a good match between them.
Resistive switching phenomena: A review of statistical physics approaches
Authors: Lee Jae Sung , Lee Shinbuhm , Noh Tae Won
Published: August 2015

Resistive switching (RS) phenomena are reversible changes in the metastable resistance state induced by external electric fields. After discovery ∼50 years ago, RS phenomena have attracted great attention due to their potential application in next-generation electrical devices. Considerable research has been performed to understand the physical mechanisms of RS and explore the feasibility and limits of such devices. There have also been several reviews on RS that attempt to explain the microscopic origins of how regions that were originally insulators can change into conductors. However, little attention has been paid to the most important factor in determining resistance: how conducting local regions are interconnected. Here, we provide an overview of the underlying physics behind connectivity changes in highly conductive regions under an electric field. We first classify RS phenomena according to their characteristic current–voltage curves: unipolar, bipolar, and threshold switchings. Second, we outline the microscopic origins of RS in oxides, focusing on the roles of oxygen vacancies: the effect of concentration, the mechanisms of channel formation and rupture, and the driving forces of oxygen vacancies. Third, we review RS studies from the perspective of statistical physics to understand connectivity change in RS phenomena. We discuss percolation model approaches and the theory for the scaling behaviors of numerous transport properties observed in RS. Fourth, we review various switching-type conversion phenomena in RS: bipolar-unipolar, memory-threshold, figure-of-eight, and counter-figure-of-eight conversions. Finally, we review several related technological issues, such as improvement in high resistance fluctuations, sneak-path problems, and multilevel switching problems.
An experimental study on the effects of rough hydrophobic surfaces on the flow around a circular cylinder
Authors: Kim Nayoung , Kim Hyunseok , Park Hyungmin
Published: August 2015

The present study investigates the effect that rough hydrophobic (or superhydrophobic) surfaces have on the flow separation and subsequent vortex structures in a turbulent wake behind a circular cylinder. The velocity fields were measured using two-dimensional particle image velocimetry in a water tunnel with Reynolds numbers of 0.7–2.3 × 104. The spray-coating of hydrophobic nanoparticles and roughened Teflon was used to produce the rough hydrophobic surfaces, and sandpapers with two different grit sizes were used to sand the Teflon into streamwise and spanwise directions, respectively, in order to examine the effect of the slip direction. The rough hydrophobic surface was found to enhance the turbulence in the flows above the circular cylinder and along the separating shear layers, resulting in a delay of the flow separation and early vortex roll-up in the wake. As a result, the size of the recirculation bubble in the wake was reduced by up to 40%, while the drag reduction of less than 10% is estimated from a wake survey. However, these effects are reversed as the Reynolds number increases. The surface texture normal to the flow direction (spanwise slip) was found to be more effective than that aligned to the flow (streamwise slip), supporting the suggested mechanism. In addition, the superhydrophobic surface is locally applied by varying the installation angle and that applied around the separation point is most effective, indicating that the rough hydrophobic surface directly affects the boundary layer at flow separation. In order to control the flow around a circular cylinder using rough hydrophobic surfaces, it is suggested to have a smaller roughness width, which can stably retain air pockets. In addition, a higher gas fraction and a more uniform distribution of the roughness size are helpful to enhance the performance such as the separation delay and drag reduction.
Rectennas at optical frequencies: How to analyze the response
Authors: Joshi Saumil , Moddel Garret
Published: August 2015

Optical rectennas, antenna-coupled diode rectifiers that receive optical-frequency electromagnetic radiation and convert it to DC output, have been proposed for use in harvesting electromagnetic radiation from a blackbody source. The operation of these devices is qualitatively different from that of lower-frequency rectennas, and their design requires a new approach. To that end, we present a method to determine the rectenna response to high frequency illumination. It combines classical circuit analysis with classical and quantum-based photon-assisted tunneling response of a high-speed diode. We demonstrate the method by calculating the rectenna response for low and high frequency monochromatic illumination, and for radiation from a blackbody source. Such a blackbody source can be a hot body generating waste heat, or radiation from the sun.
Impact of dynamic specimen shape evolution on the atom probe tomography results of doped epitaxial oxide multilayers: Comparison of experiment and simulation
Authors: Madaan Nitesh , Bao Jie , Nandasiri Manjula , Xu Zhijie , Thevuthasan Suntharampillai , Devaraj Arun
Published: August 2015

The experimental atom probe tomography (APT) results from two different specimen orientations (top-down and sideways) of a high oxygen ion conducting Samaria-doped-ceria/Scandia-stabilized-zirconia multilayer thin film solid oxide fuel cell electrolyte was compared with level-set method based field evaporation simulations for the same specimen orientations. This experiment-simulation comparison explains the dynamic specimen shape evolution and ion trajectory aberrations that can induce density artifacts in final reconstruction, leading to inaccurate estimation of interfacial intermixing. This study highlights the importance of comparing experimental results with field evaporation simulations when using APT to study oxide heterostructure interfaces.
Increased p-type conductivity in GaNxSb1−x, experimental and theoretical aspects
Authors: Segercrantz N. , Makkonen I. , Slotte J. , Kujala J. , Veal T. D. , Ashwin M. J. , Tuomisto F.
Published: August 2015

The large increase in the p-type conductivity observed when nitrogen is added to GaSb has been studied using positron annihilation spectroscopy and ab initio calculations. Doppler broadening measurements have been conducted on samples of GaNxSb1−x layers grown by molecular beam epitaxy, and the results have been compared with calculated first-principle results corresponding to different defect structures. From the calculated data, binding energies for nitrogen-related defects have also been estimated. Based on the results, the increase in residual hole concentration is explained by an increase in the fraction of negative acceptor-type defects in the material. As the band gap decreases with increasing N concentration, the ionization levels of the defects move closer to the valence band. Ga vacancy-type defects are found to act as positron trapping defects in the material, and the ratio of Ga vacancy-type defects to Ga antisites is found to be higher than that of the p-type bulk GaSb substrate. Beside Ga vacancies, the calculated results imply that complexes of a Ga vacancy and nitrogen could be present in the material.
Collective electronic behaviors of laterally heterostructured armchair MoS2-NbS2 nanoribbons
Authors: Wu Nannan , Yang Zhixiong , Zhou Wenzhe , Zou Hui , Xiong Xiang , Chen Yu , Ouyang Fangping
Published: August 2015

Based on density functional theory, we have investigated the electronic properties of molybdenum disulfide-niobium disulfide hybrid nanoribbons (MoS2-NbS2 NRs). It is found that the MoS2 edge, MoS2 center, NbS2 edge, and NbS2 center have distinct contributions to the collective electronic behaviors of MoS2-NbS2 NRs. Its behavior, metallic or semiconductor, depends on whether the central area of NR contains NbS2 chain or not. This dependence has been also revealed in the electronic structures of NbS2-MoS2-NbS2 NR and MoS2-NbS2-MoS2 NR, of which the former is semiconductor and the latter is metal. In comparison with MoS2 NR of the same width, the hybrid has a different bandgap that was caused by the coupled effects between NbS2 edge and MoS2 edge. This fact makes MoS2-NbS2 NRs a possible candidate for nanoelectronic devices based on heterostructured transition-metal dichalcogenide.
Core-halo limit and internal dynamics of high intensity beams
Authors: Nghiem P. A. P. , Valette M. , Chauvin N. , Pichoff N. , Uriot D.
Published: August 2015

The dynamics of high-intensity beams largely depends on their internal space charge forces. These forces are responsible of non-linear coupling, emittance growth, and halo generation. They contribute to shape the beam density profile. As a consequence, an analysis of this profile can be a precious indicator capable of revealing the internal dynamics of the beam. This paper recalls the precise core-halo limit determination proposed earlier, then studies its behavior through a wide range of beam profiles, and finally shows its relevance as an indicator of the limit separating the two space charge field regimes of the core and the halo.
Evaluation of the energy-saving and emission-reduction potential for Chinese provinces based on regional difference coefficients
Authors: Guo Ling-ling , Wu Chun-you , Qu Ying , Yu Jing-tao
Published: August 2015

Rapid economic growth has resulted in a severe energy shortage and extensive environmental pollution in China. The question of how to save energy and reduce emissions has become a popular topic not only in economic but also in political and social circles. Most of the previous studies on the subject were conducted to evaluate the potential for energy savings and emission reductions. As an indispensable factor, each region's external environment has a strong impact on evaluating its potential for energy savings and emission reductions. However, the prior studies seldom considered each region's external environment, which resulted in research findings that are not rationally convincing. Hence, in this paper, a regional difference coefficient is introduced and calculated by applying technique for order preference by similarity to ideal solution to represent the external environment from two perspectives: (1) each region's economic and technical ability and (2) each region's resource reserves and supplies ability. Based on the regional difference coefficients, the original data envelopment analysis model was modified to calculate the potential for energy savings and emission reductions for 30 provincial administrative regions in China from the year 2001–2011. The results show that the gaps in the energy-saving and emission-reduction potential among these 30 regions are large and still increasing. Each region has its own causes for changes in energy savings and emission reductions. Thus, the important factors influencing regional energy savings and emission reductions are analyzed. The paper finds that technical progress and economic strength are the main factors impacting the regional energy-saving performance, especially in the underdeveloped provinces, while the industrial structure and energy mix are important factors influencing China's emission-reduction performance.
Multilayer Ge nanocrystals embedded within Al2O3 matrix for high performance floating gate memory devices
Authors: Bar R. , Aluguri R. , Manna S. , Ghosh A. , Satyam P. V. , Ray S. K.
Published: August 2015

Metal-insulator-silicon devices with Ge nanocrystals dispersed in Al2O3 have been studied with a view to exploit them for floating gate memory applications. Multilayer devices comprising of five layers Ge nanocrystals have exhibited superior memory characteristics over the single layer Ge and multilayer Si nanocrystals reported in literature. The effect of interface traps on the memory behavior using frequency dependent capacitance- and conductance-voltage measurements has been investigated. This study has demonstrated an enhanced memory window with superior retention characteristics, owing to the Coulomb blockade effect, due to the introduction of multi-layer nanocrystals in the floating gate.
Quasimonoenergetic electron beam and brilliant gamma-ray radiation generated from near critical density plasma due to relativistic resonant phase locking
Authors: Liu B. , Hu R. H. , Wang H. Y. , Wu D. , Liu J. , Chen C. E. , Meyer-ter-Vehn J. , Yan X. Q. , He X. T.
Published: August 2015

We show that a high current quasi-monoenergetic electron beam and a peaked brilliant gamma-ray beam can be generated by irradiating an ultra-intense laser pulse on uniform near critical density plasma, with a laser spot radius RL∼(λ/π)2a/n, here λ is the laser wave length, a denotes the normalized laser intensity, and n denotes the normalized plasma density. Due to a relativistic resonant phase locking mechanism, high energy oscillating electrons are trapped to ride on the laser electric field, and an unprecedented ultra-fast ultra-brilliant gamma-ray pulse is emitted from the electrons. Both the high energy electrons and gamma-ray photons are emitted in a small polar angle range. It is similar to a conventional wiggler synchrotron, except that the curvature radius of electron orbits in the laboratory coordinate frame measures in microns rather than in meters.
Water orientation at hydrophobic interfaces
Authors: Strazdaite Simona , Versluis Jan , Bakker Huib J.
Published: August 2015

We study the structure and orientation of water molecules at water/alkane and water/polydimethylsiloxane interfaces with surface specific intensity and heterodyne-detected vibrational sum-frequency generation (HD-VSFG) spectroscopy. We observe that the hydrogen-bond structure of the water molecules is enhanced at these interfaces compared to the water/air interface. We also find that the water molecules at the interface show a net orientation of their O–H groups pointing towards to the hydrophobic layer.
Chloride-based route for monodisperse Cu2ZnSnS4 nanoparticles preparation
Authors: Azanza Ricardo Cristy Leonor , Girardi Fabrizio , Cappelletto Elisa , D'Angelo Renato , Ciancio Regina , Carlino Elvio , Ricci Pier Carlo , Malerba Claudia , Mittiga Alberto , Di Maggio Rosa , Scardi Paolo
Published: August 2015

A new approach based on hot injection method is proposed to gram-scale Cu2ZnSnS4 nanoparticles production minimizing the use of organic solvents. Nanocrystal synthesis was performed starting from metal chlorides and pure sulphur powder and using Oleylamine as capping agent. As a result, core-shell nanoparticles with a narrow size distribution were obtained.
MHD flow of Burger’s fluid over an off-centered rotating disk in a porous medium
Authors: Khan Najeeb Alam , Khan Sidra , Ullah Saif
Published: August 2015

In this study, off-centered stagnation flow of three dimensional Burger’s fluid over an infinite rotating disk in a porous medium with a uniform magnetic field, which is applying normal to the disk, is investigated. A uniform suction/injection is applied through the surface of the porous disk. The structure has been modeled in the form of ordinary differential equations, which are reduced from partial differential equations by using the similarity transformation. Analytical solution is obtained by non-perturbation technique of homotopy analysis method (HAM). The influence of non-dimensional parameters on velocity profile is presented in graphical form and the numerical comparison is made with the viscous fluid as a special case.
Effect of voltage polarity on the plasma-liquid interactions
Authors: Kang Woo Seok , Hur Min , Song Young-Hoon
Published: August 2015

This letter reports on how voltage polarity affects the plasma-liquid interactions. Unique electrical characteristics are observed because of the conductive and dielectric nature of the electrolyte, which may control the accumulation and dispersion of surface charges over the liquid. Depending on the voltage polarity, distinct spatio-temporal images of the optical emissions are observed; subject to a positive voltage, sodium emissions after evaporation are observed only at the interface, while the sodium emissions are gradually transported to the discharge region because of the motion of the sodium cations in the direction of the electric field during the negative voltage phase. Changing the duty ratio clearly shows that the phenomenon is affected by the voltage polarity.
Stability of organometal perovskites with organic overlayers
Authors: Tran Catherine D. T. , Liu Yi , Thibau Emmanuel S. , Llanos Adrian , Lu Zheng-Hong
Published: August 2015

The air-stability of vapour-phase-deposited methylammonium lead triiodide (CH3NH3PbI3) perovskite thin films has been studied using X-ray diffraction. It is found that the perovskite structure without organic coating decomposes completely within a short period of time (∼two days) upon exposure to ambient environment. The degradation of the perovskite structure is drastically reduced when the perovskite films are capped with thin N,N′-Di(1-naphthyl)-N,N′-diphenyl-(1,1′-biphenyl)-4,4′-diamine (NPB) films. We discovered that the amount of lead iodide (PbI2), a product of the degradation, grows as a function of time in a sigmoidal manner. Further mathematical modeling analysis shows that the perovskite degradation follows the Avrami equation, a kinetics theory developed for quantifying phase transformations in solid-state materials.
Synthesis and Characterization of a New Group of Exo-Coordinating O2N2-Donor Macrocycles
Authors: Ghanbari Bahram , Safarkoopayeh (Agheli) Barzin , Kia Reze , Raithby Paul R.
Published: August 2015

The reaction of 15–18 membered benzodiazacrown ethers with salicylaldehyde afforded n-membered O2N2-donor macrocyclic ligands mounted with 1,3-diazacyclohexane subrings (1–4) in high yields. The products were characterized by FT-IR, 1H, 13C NMR spectroscopy, elemental analyses, and single crystal X-ray studies. The solid state structures revealed strong intramolecular hydrogen bonding between the pendant phenolic group and the tertiary nitrogen of the corresponding macroring.
Synthetic, Spectroscopic, Crystallographic, and Biological Studies of Seven-Coordinated Diorganotin(IV) Complexes Derived from Schiff Bases and Pyridinic Carboxylic Acids
Authors: Chans Guillermo M. , Nieto-Camacho Antonio , Ramírez-Apan Teresa , Hernández-Ortega Simón , Álvarez-Toledano Cecilio , Gómez Elizabeth
Published: August 2015

The synthesis and characterisation of diorganotin(iv) monomeric derivatives of pyridine Schiff bases and pyridinic carboxylic acids are reported. All complexes were characterised by mass spectrometry, elemental analyses, IR spectra, and multinuclear NMR analyses. Among them, complexes 5a, 5d, 5e, 5g, and 6a were also confirmed by X-ray crystallography diffraction analyses, which led to establishing that the tin atom is seven-coordinated and has a distorted pentagonal–bipyramidal coordination environment in the solid state and also revealed that both ligands occupy the equatorial positions and the organic substituents the axial positions. The antioxidant activity of the synthetic derivatives towards 1,1-diphenyl-2-picrylhydrazyl radical (DPPH) as well as the thiobarbituric acid reactive substances (TBARS) assay were determined, and were compared with standard antioxidants, showing a dose-dependent activity in both cases. A prominent response was obtained depending on the substituent. The anti-inflammatory activity was also evaluated on a 12-O-tetradecanoylphorbol-13-acetate (TPA) model of induced acute inflammation. The results of the biological tests are discussed in terms of structural characteristics.
Implications of environmental trajectories for Limits of Acceptable Change: a case study of the Riverland Ramsar site, South Australia
Authors: Newall Peter R. , Lloyd Lance N. , Gell Peter A. , Walker Keith F.
Published: August 2015

The Riverland Ramsar site in south-eastern Australia has Limits of Acceptable Change (LAC) derived on the basis of hydrological regimes and vegetation requirements. This study evaluated LAC for the site against trajectories of environmental change including increasing river regulation and changing climate. The study identified a high likelihood of exceedances of the LAC from changed hydrologic regime and also from changing climate, with the combined influences increasing the likelihood of breaches. Regional climatic variations in the past call into question the concept of baseline conditions for this site and elsewhere, and suggest that management plans based on ecological variation around a point in time will be insufficient. Vulnerability assessment, adaptation enhancement, and regular reviews of site condition and regional significance are suggested components for future management of Ramsar sites.
The Gippsland Lakes: management challenges posed by long-term environmental change
Authors: Boon Paul I. , Cook Perran , Woodland Ryan
Published: August 2015

The Gippsland Lakes, listed under the Ramsar Convention in 1982, have undergone chronic salinisation since the cutting in 1889 of an artificial entrance to the ocean to improve navigational access, exacerbated in the mid–late 20th century by increasing regulation and extraction of water from inflowing rivers. Both developments have had substantial ecological impacts: a marked decline in the area of reed (Phragmites australis) beds; the loss of salt-intolerant submerged taxa such as Vallisneria australis, causing a shift to a phytoplankton-dominated system in Lake Wellington; and, nearer the entrance, an expansion in the area of seagrasses. Mangroves (Avicennia marina) first appeared in the late 1980s or early 1990s. Since 1986 recurring blooms of Nodularia spumigena have led to loss of recreational amenity and to the periodic closure of recreational and commercial fisheries. Changes to hydrological and salinity regimes have almost certainly shifted the contemporary fish community away from the pre-entrance state. Rises in eustatic sea levels and increases in storm surges will exacerbate the issue of chronic salinisation. Whether or not managers choose to intervene to prevent, or at least minimise, ongoing environmental change will inevitably prove controversial, and in some cases no socially or technologically feasible solutions may exist.
Assessing wetland degradation and loss of ecosystem services in the Niger Delta, Nigeria
Authors: Ayanlade Ayansina , Proske Ulrike
Published: August 2015

The Niger Delta, being the most extensive freshwater wetland and aquatic ecosystem in West Africa, provides numerous services both to local people and to the West African economy. Ongoing environmental pressure exerted by large-scale oil extraction and illegal timber logging, however, are suspected to have had a substantial impact on the Delta’s ecosystems over the last decades. Knowledge on impact of these activities on the region’s wetlands now or in the past is scarce and patchy. To address this lack of knowledge, this study assesses spatiotemporal changes in two wetlands in the region by using satellite data from 1984 to 2011 and GIS methods. The results show that both wetlands have experienced substantial degradation, particularly with respect to the area of forest lost. Although comprehensive environmental protection laws were introduced in 1988, ecosystem services of up to US$65 million in value were lost over the study period. The introduction of new legislation in 2007, however, is potentially a first step towards a more ‘wise use’ of wetlands in Nigeria.
Long-distance spotting potential of bark strips of a ribbon gum (Eucalyptus viminalis)
Authors: Hall James , Ellis Peter F. , Cary Geoffrey J. , Bishop Glenys , Sullivan Andrew L.
Published: August 2015

Firebrands of ribbon bark eucalypt are notorious for igniting spotfires many kilometres ahead of a bushfire. However, no research to date has demonstrated that this bark type can sustain combustion at its terminal velocity for the travel time required. Fifty samples of shed bark of Eucalyptus viminalis of three distinct morphologies were ignited at one end and burned tethered in a vertical wind tunnel at air velocities approximating their terminal velocity. Mean terminal velocity and burnout time for ‘flat plates’, ‘simple cylinders’ and ‘internally convoluted cylinders’ were 5.4 m s–1 and 251 s; 5.2 m s–1 and 122 s; and 5.8 m s–1 and 429 s. The corresponding maximum burnout times were 785 s, 353 s and 1304 s. One internally convoluted cylinder flamed continuously and consumed its length of 368 mm in 271 s. The maximum burnout time for the internally convoluted cylinders is commensurate with a potential spotting distance exceeding 20 km given a mean wind speed during transport of 60 km h–1. This is the first study in which combustion times exceeding a few minutes have been recorded for this bark morphology, and thus provides some corroboration of the notoriety for long-distance spotting.
Fire severity estimation from space: a comparison of active and passive sensors and their synergy for different forest types
Authors: Tanase M. A. , Kennedy R. , Aponte C.
Published: August 2015

Monitoring fire effects at landscape level is viable from remote sensing platforms providing repeatable and consistent measurements. Previous studies have estimated fire severity using optical and synthetic aperture radar (SAR) sensors, but to our knowledge, none have compared their effectiveness. Our study carried out such a comparison by using change detection indices computed from pre- and post-fire Landsat and L-band space-borne SAR datasets to estimate fire severity for seven fires located on three continents. Such indices were related to field-estimated fire severity through empirical models, and their estimation accuracy was compared. Empirical models based on the joint use of optical and radar indices were also evaluated. The results showed that optic-based indices provided more accurate fire severity estimates. On average, overall accuracy increased from 61% (SAR) to 76% (optical) for high-biomass forests. For low-biomass forests (i.e. aboveground biomass levels below the L-band saturation point), radar indices provided comparable results; overall accuracy was only slightly lower when compared with optical indices (69% vs 73%). The joint use of optical and radar indices decreased the estimation error and reduced misclassification of unburned forest by 9% for eucalypt and 3% for coniferous forests.
Population regulation of African buffalo in the Mara–Serengeti ecosystem
Authors: Dublin Holly T. , Ogutu Joseph O.
Published: August 2015

Context The processes regulating ungulate populations have been the focus of numerous studies. For the African buffalo (Syncerus caffer Sparrman) population inhabiting the Mara–Serengeti ecosystem, rinderpest was the primary regulatory factor up to the mid-1960s. Following reduction of rinderpest and buffalo population increase, interspecific competition for food, notably with cattle and wildebeest (Connochaetes taurinus Burchell), was thought to be the primary regulatory factor in the ecosystem. Aims We analysed buffalo population trends and the relationship between buffalo population growth and rainfall and density dependence in the Mara–Serengeti ecosystem and discuss the findings in the context of the key ecosystem processes governing buffalo population dynamics in African savannas, namely, food limitation, competition, predation, disease and land use changes. Methods We analysed buffalo population dynamics in the Mara–Serengeti ecosystem in relation to rainfall and density dependence feedback between 1984 and 2010. Key results Buffalo population growth was both significantly density-dependent and positively correlated with the dry season rainfall after, but not before, a severe drought in 1993. Buffalo numbers crashed by 48.6% in 1984–85 and by 76.1% in 1993–94 during severe droughts when food availability was lowest and competition with the more numerous cattle and wildebeest was highest. Conclusions Recovery of buffalo numbers to pre-drought levels took 8–9 years after the 1984–85 drought but was much slower, with buffaloes numbering merely 36% of their 1993 population (12 895 animals) 18 years after the 1993–94 drought despite intermittent periods of high rainfall, probably due to demographic and/or reproductive factors, heightened competition with livestock, land use changes in the adjoining pastoral ranches, lion predation and recurrent severe droughts. Implications Our findings demonstrate how food limitation caused by droughts associated with the hemispheric El Niño–Southern Oscillation can cause severe declines in and threaten the persistence of large ungulate populations. The findings also portray how density-dependent food limitation, competition, predation, land use changes and other factors can accentuate the effect of droughts and greatly prolong population recovery.
Characterisation of 14 microsatellite markers for the Australian fig psylloid, Mycopsylla fici
Authors: Fromont Caroline , Riegler Markus , Cook James M.
Published: August 2015

The Australian fig psylloid, Mycopsylla fici, is a sap-feeding insect herbivore that is host-specific to the Moreton Bay fig, Ficus macrophylla. It has periodic major outbreaks that can cause complete defoliation of individual trees and massive decrease in local leaf and fruit availability, with significant effects for many insect and vertebrate species that utilise the tree’s resources. We used ⅛ of an Illumina MiSeq run to sequence genomic DNA from two pools of five psylloids from two different field sites. We identified 14 polymorphic microsatellite loci and characterised them in 43 individuals from two populations (Sydney and Lord Howe Island, Australia). Within populations, the number of alleles ranged from 4 to 15 per locus with observed heterozygosity of 0–0.9. Four loci deviated from Hardy–Weinberg equilibrium. The microsatellite primers will be useful for the study of population genetics and gene flow within and between psylloid populations.
Three Southern shibboleths
Authors: Vosters Rik , Rutten Gijsbert
Published: August 2015

Over the course of the long eighteenth century, a distinct Southern Dutch linguistic identity emerged in the region now known as Flanders, and spelling features are at the heart of this developing linguistic autonomy. By analyzing eighteenth- and early-nineteenth-century normative and metalinguistic comments about three highly salient spelling variables (the spelling of the long vowelsaanduin closed syllables, the ending 〈-n〉 or 〈-ø〉 in masculine adnominals, and the orthographic representation of etymologically differenteandosounds), we will show how seemingly insignificant features increasingly came to be portrayed as representing an unbridgeable linguistic gap between the Northern and Southern Low Countries. At the time of the political reunion of both parts of the Dutch speaking territories (1815–1830), this perceived gap then gave rise to different voices rejecting or embracing these shibboleths of linguistic ‘Southernness’, indicating how spelling features came to represent conflicting identities.
Oogenesis and Fecundity Type of Gray Triggerfish in the Gulf of Mexico
Authors: Lang Erik T. , Fitzhugh Gary R.
Published: August 2015

The fecundity of Gray Triggerfish Balistes capriscus has been difficult to estimate, as few imminently spawning or recently spawned females have been detected. Our study focused on verifying the pattern of oogenesis and fecundity type in Gray Triggerfish. During 1999–2012, females (n = 1,092) were collected from the eastern Gulf of Mexico, and subsets of these fish were used to calculate condition indices and assess ovarian histology. The gonadosomatic index, hepatosomatic index, and Fulton's condition factor indicated that liver and somatic energy stores increased prior to spawning and were depleted throughout the spawning period, characteristic of a capital pattern of energy storage and allocation to reproduction. Typical of a capital breeding pattern, we also observed (1) a hiatus in oocyte size distribution and (2) group-synchronous oogenesis, which are both traits of a determinate fecundity type. However, evidence that fecundity was not set prior to spawning included the observation of “de novo” vitellogenesis during the spawning season; secondary oocytes increased in number and failed to increase in mean size over time. Thus, Gray Triggerfish exhibit an indeterminate fecundity type with mixed reproductive traits that may characterize species exhibiting female parental care in warmwater environments. Further, we estimated the secondary oocyte growth rate (37 m/d) based upon the time lag of postovulatory follicle (POF) degeneration. Using oocyte growth rate and the proportion of females bearing POFs, the interspawning interval was estimated to range from 8 to 11 d, indicating that 8–11 batches/female could be produced during the estimated 86-d reproductive period. The hiatus in oocyte size distribution was used to define a minimum size (250 m) from which to distinguish an advancing batch of secondary growth oocytes. Batch fecundity (BF) ranged from 0.34 to 1.99 million eggs and was significantly related to FL (mm): BF = 8,703.69·FL – 1,776,483 (r2 = 0.56).

Received October 10, 2014; accepted June 27, 2015
Annexin A2–dependent actin bundling promotes secretory granule docking to the plasma membrane and exocytosis
Authors: Gabel Marion , Delavoie Franck , Demais Valérie , Royer Cathy , Bailly Yannick , Vitale Nicolas , Bader Marie-France , Chasserot-Golaz Sylvette
Published: August 2015

Annexin A2, a calcium-, actin-, and lipid-binding protein involved in exocytosis, mediates the formation of lipid microdomains required for the structural and spatial organization of fusion sites at the plasma membrane. To understand how annexin A2 promotes this membrane remodeling, the involvement of cortical actin filaments in lipid domain organization was investigated. 3D electron tomography showed that cortical actin bundled by annexin A2 connected docked secretory granules to the plasma membrane and contributed to the formation of GM1-enriched lipid microdomains at the exocytotic sites in chromaffin cells. When an annexin A2 mutant with impaired actin filament–bundling activity was expressed, the formation of plasma membrane lipid microdomains and the number of exocytotic events were decreased and the fusion kinetics were slower, whereas the pharmacological activation of the intrinsic actin-bundling activity of endogenous annexin A2 had the opposite effects. Thus, annexin A2–induced actin bundling is apparently essential for generating active exocytotic sites.
PI(3,5)P2 controls endosomal branched actin dynamics by regulating cortactin–actin interactions
Authors: Hong Nan Hyung , Qi Aidong , Weaver Alissa M.
Published: August 2015

Branched actin critically contributes to membrane trafficking by regulating membrane curvature, dynamics, fission, and transport. However, how actin dynamics are controlled at membranes is poorly understood. Here, we identify the branched actin regulator cortactin as a direct binding partner of phosphatidylinositol 3,5-bisphosphate (PI(3,5)P2) and demonstrate that their interaction promotes turnover of late endosomal actin. In vitro biochemical studies indicated that cortactin binds PI(3,5)P2 via its actin filament-binding region. Furthermore, PI(3,5)P2 competed with actin filaments for binding to cortactin, thereby antagonizing cortactin activity. These findings suggest that PI(3,5)P2 formation on endosomes may remove cortactin from endosome-associated branched actin. Indeed, inhibition of PI(3,5)P2 production led to cortactin accumulation and actin stabilization on Rab7+ endosomes. Conversely, inhibition of Arp2/3 complex activity greatly reduced cortactin localization to late endosomes. Knockdown of cortactin reversed PI(3,5)P2-inhibitor–induced actin accumulation and stabilization on endosomes. These data suggest a model in which PI(3,5)P2 binding removes cortactin from late endosomal branched actin networks and thereby promotes net actin turnover.
Usp16 regulates kinetochore localization of Plk1 to promote proper chromosome alignment in mitosis
Authors: Zhuo Xiaolong , Guo Xiao , Zhang Xiaoyan , Jing Guihua , Wang Yao , Chen Qiang , Jiang Qing , Liu Junjun , Zhang Chuanmao
Published: August 2015

During the G2 to M phase transition, a portion of mitotic regulator Plk1 localizes to the kinetochores and regulates the initiation of kinetochore–microtubule attachments for proper chromosome alignment. Once kinetochore–microtubule attachment is achieved, this portion of Plk1 is removed from the kinetochores as a result of ubiquitination. However, the crucial molecular mechanism that promotes the localization and the maintenance of Plk1 on the kinetochores until metaphase is still unclear. We report that ubiquitin-specific peptidase 16 (Usp16) plays a key role during this process. Usp16 deubiquitinates Plk1, resulting in an enhanced interaction with kinetochore-localized proteins such as BubR1, and thereby retains Plk1 on the kinetochores to promote proper chromosome alignment in early mitosis. Down-regulation of Usp16 causes increased ubiquitination and decreased kinetochore localization of Plk1. Thus, our data unveil a unique mechanism by which Usp16 promotes the localization and maintenance of Plk1 on the kinetochores for proper chromosome alignment.
Degradation of HK2 by chaperone-mediated autophagy promotes metabolic catastrophe and cell death
Authors: Xia Hong-guang , Najafov Ayaz , Geng Jiefei , Galan-Acosta Lorena , Han Xuemei , Guo Yuan , Shan Bing , Zhang Yaoyang , Norberg Erik , Zhang Tao , Pan Lifeng , Liu Junli , Coloff Jonathan L. , Ofengeim Dimitry , Zhu Hong , Wu Kejia , Cai Yu , Yates John R. , Zhu Zhengjiang , Yuan Junying , Vakifahmetoglu-Norberg Helin
Published: August 2015

Hexokinase II (HK2), a key enzyme involved in glucose metabolism, is regulated by growth factor signaling and is required for initiation and maintenance of tumors. Here we show that metabolic stress triggered by perturbation of receptor tyrosine kinase FLT3 in non–acute myeloid leukemia cells sensitizes cancer cells to autophagy inhibition and leads to excessive activation of chaperone-mediated autophagy (CMA). Our data demonstrate that FLT3 is an important sensor of cellular nutritional state and elucidate the role and molecular mechanism of CMA in metabolic regulation and mediating cancer cell death. Importantly, our proteome analysis revealed that HK2 is a CMA substrate and that its degradation by CMA is regulated by glucose availability. We reveal a new mechanism by which excessive activation of CMA may be exploited pharmacologically to eliminate cancer cells by inhibiting both FLT3 and autophagy. Our study delineates a novel pharmacological strategy to promote the degradation of HK2 in cancer cells.
Jump-starting life? Fundamental aspects of synthetic biology
Authors: Schwille Petra
Published: August 2015

What is life and how could it originate? This question lies at the core of understanding the cell as the smallest living unit. Although we are witnessing a golden era of the life sciences, we are ironically still far from giving a convincing answer to this question. In this short article, I argue why synthetic biology in conjunction with the quantitative sciences may provide us with new concepts and tools to address it.
Multi-modality management of craniopharyngioma: a review of various treatments and their outcomes
Authors: Varlotto John , DiMaio Christopher , Grassberger Clemens , Tangel Matthew , Mackley Heath , Pavelic Matt , Specht Charles , Sogge Steven , Nguyen Dan , Glantz Michael , Saw Cheng , Upadhyay Urvashi , Moser Richard , Yunus Shakeeb , Rava Paul , Fitzgerald Thomas , Glanzman Jonathan , Sheehan Jonas
Published: August 2015

Craniopharyngioma is a rare tumor that is expected to occur in ∼400 patients/year in the United States. While surgical resection is considered to be the primary treatment when a patient presents with a craniopharyngioma, only 30% of such tumors present in locations that permit complete resection. Radiotherapy has been used as both primary and adjuvant therapy in the treatment of craniopharyngiomas for over 50 years. Modern radiotherapeutic techniques, via the use of CT-based treatment planning and MRI fusion, have permitted tighter treatment volumes that allow for better tumor control while limiting complications. Modern radiotherapeutic series have shown high control rates with lower doses than traditionally used in the two-dimensional treatment era. Intracavitary radiotherapy with radio-isotopes and stereotactic radiosurgery may have a role in the treatment of recurrent cystic and solid recurrences, respectively. Recently, due to the exclusive expression of the Beta-catenin clonal mutations and the exclusive expression of BRAF V600E clonal mutations in the overwhelming majority of adamantinomatous and papillary tumors respectively, it is felt that inhibitors of each pathway may play a role in the future treatment of these rare tumors.
Multiple Quality Characteristics Optimization of Ball Grid Array Wire Bonding Process
Authors: Yih-Fong Tzeng , Fu-Chen Chen , Chih-Huang Chen
Published: August 2015

This paper presents an integrated approach combining principal component analysis (PCA) and Taguchi methods to develop a ball grid array (BGA), gold (Au) wire bonding process with multiple quality characteristics optimization. Eight main process factors of BGA wire bonding technology are selected as the control factors for parameter design. They are the factor A (seating ultrasonic generator (USG)), factor B (TIP height), factor C (C/V), factor D (USG current), factor E (USG bond time), factor F (bond force), factor G (FS threshold), and factor H (FAB size). The quality characteristics of the process in the study, including the wire pull strength, the ball shear strength, the ball thickness difference, the ball size difference, and the percentage of the Au–Al intermetallic compound (IMC) are measured. The optimal process parameters that meet the requirements for multiple quality characteristics are A1B3C1D3E3F1G1H2. They are then used to be tested for verification. Experimental results confirm that the optimal process design indeed enhances the quality characteristics investigated. The analysis of variance (ANOVA) results also show that the most important control factors affecting the quality characteristics are factor B (TIP height), factor C (C/V), and factor G (FS threshold), which accounts for 72.34% of total process variance. Thus, they must be strictly monitored during processing.
Microwave Absorbing Properties of Lightweight Nanocomposite/Honeycomb Sandwich Structures
Authors: Khurram A. A. , Rakha Sobia A. , Ali Naveed , Asim M. T. , Guorui Zhang , Munir Arshad
Published: August 2015

Thin glass-fiber/epoxy-composite sheets filled with multiwalled carbon nanotubes (MWCNTs) are manufactured to make lightweight honeycomb sandwich microwave absorbers. A multilayered sandwich structure of thin nanocomposite sheets and honeycomb spacers have been also proposed and developed to work in a wide frequency range. The nanocomposite sheets are prepared from 0.5, 1.0, 1.5, 2.0, and 2.5 wt. % of MWCNTs. A commercially available simulation software computer simulation technology (CST) microwave studio was used for the designing and development of radar absorbing structure (RAS) composed of MWCNTs/glass-fiber/epoxy-composite sheets and honeycomb cores. The measurements of return loss (RL) from sandwich structures with 5 mm and 20 mm honeycomb cores in the Ku band (11–17 GHz) show that maximum RL is achieved at 11 GHz and 16 GHz, respectively. The stacking of three nanocomposite sheets and three 5 mm-thick honeycomb spacers produced a wide band microwave absorber with −10 dB RL over 9 GHz bandwidth.