bluuebunny/crossref_metadata_2025 huggingface dataset:
Characteristics of backward and forward two-particle relative dispersion in turbulence at different Reynolds numbers
Authors: Buaria D. , Sawford Brian L. , Yeung P. K.
Published: October 2015

A new algorithm based on post-processing of saved trajectories has been developed and applied to obtain well-sampled backward and forward relative dispersion statistics in stationary isotropic turbulence, over a range of initial separations ranging from Kolmogorov to energy-containing scales. Detailed results are obtained over a range of Taylor-scale Reynolds numbers, up to 1000, which is higher than in recent work in the literature. Backward dispersion is faster, especially at intermediate times after the ballistic range and before long-time diffusive behavior is reached. Richardson scaling has been demonstrated for the mean-squared separation, and forward and backward Richardson constants estimated to be gf = 0.55 and gb = 1.5, which are close to or comparable to other estimates. However, because of persistent dissipation sub-range effects no corresponding scaling was observed for higher order moments of the separation. Analysis of the separation probability density function showed only transitory agreement with the well-known Richardson prediction. The strong exponential growth of the separation on dissipation sub-range scales was analyzed in terms of a central limit theory approximation. The resulting predictions for the ratio of the growth rates of the third- and fourth-order moments are reasonably consistent with the theory. The backward growth rates, corresponding to the ratio of the magnitude of the smallest to largest Lyapunov exponents, are about 50% greater than the forward growth rates, somewhat higher than other estimates. The predicted asymmetry between backward and forward relative displacements at early times, manifested in a t3 variation of the difference in the backward and forward mean-square relative displacement, was confirmed numerically and explicitly traced to Eulerian properties at the small scales. However, this t3 growth is not simply connected to the t3 growth in the Richardson regime and the asymmetry manifested there by the difference in the backward and forward Richardson constants. Asymmetry in time for higher order moments was also explained using a Taylor-series analysis at early times.
Direct writing the selective emitter of solar cell with lateral ultrasonic spray laser doping technique
Authors: Song Jingwei , Wang Xuemeng , Gong Li , Lin Yanghuan , Gao Xiaodong , Huang Jiapei , Shen Hui
Published: October 2015

In recent years, laser doping of selective emitters has offered an attractive method to improve the performance of silicon solar cell. A simple laser process is presented for the local doping of crystalline silicon solar cells. Here, the doped line has been direct-written by a 532 nm wavelength laser combined with lateral ultrasonic spray using phosphoric acid. The laser doping selective emitter was quantitatively and spatially measured using Kelvin probe force microscopy under external light illumination. By using the exploited system, we could pattern the dielectric layer while simultaneously doping the underlying silicon to easily achieve the selective emitter (n++) in one processing step. With argon as the conveyance gas, the local melted Si was surrounded by the air-argon gas mixture in the entire process, which caused a decrease in oxygen incorporation.
Accessing a growth window for SrVO3 thin films
Authors: Brahlek Matthew , Zhang Lei , Eaton Craig , Zhang Hai-Tian , Engel-Herbert Roman
Published: October 2015

Stoichiometric SrVO3 thin films were grown over a range of cation fluxes on (001) (La0.3Sr0.7)(Al0.65Ta0.35)O3 substrates using hybrid molecular beam epitaxy, where a thermal effusion cell was employed to generate a Sr flux and V was supplied using the metal-organic precursor vanadium oxytriisopropoxide (VTIP). By systematically varying the VTIP flux while keeping the Sr flux constant, a range of flux ratios were discovered in which the structural and electronic properties of the SrVO3 films remained unaltered. The intrinsic film lattice parameter and residual resistivity were found to be the smallest inside the growth window, indicating the lowest defect concentration of the films, and rapidly increased for cation flux ratios deviating from ideal growth condition. Reflection high-energy electron diffraction showed that films grown within this range had smooth surfaces and diffraction patterns were free of additional spots, while otherwise the growing surface was rough and contained additional crystalline phases. Results show the existence of a SrVO3 growth window at sufficiently high growth temperature, in which high-quality, stoichiometric films can be grown in a robust, highly reproducible manner that is invulnerable to unintentional flux variation.
Relevance of non-equilibrium defect generation processes to resistive switching in TiO2
Authors: Abdelouahed Samir , McKenna Keith P.
Published: October 2015

First principles calculations are employed to identify atomistic pathways for the generation of vacancy-interstitial pair defects in TiO2. We find that the formation of both oxygen and titanium defects induces a net dipole moment indicating that their formation can be assisted by an electric field. We also show that the activation barrier to formation of an oxygen vacancy defect can be reduced by trapping of holes which may be injected by the electrode. The calculated activation energies suggest that generation of titanium defects is more favorable than generation oxygen defects although activation energies in both cases are relatively high (>3.3 eV). These results provide much needed insight into an issue that has been widely debated but for which little definitive experimental information is available.
Direct measurements of the magnetic entropy change
Authors: Nielsen K. K. , Bez H. N. , von Moos L. , Bjørk R. , Eriksen D. , Bahl C. R. H.
Published: October 2015

An experimental device that can accurately measure the magnetic entropy change, Δs, as a function of temperature, T, and magnetic field, H, is presented. The magnetic field source is in this case a set of counter-rotating concentric Halbach-type magnets, which produce a highly homogeneous applied field with constant orientation. The field may be varied from 0 to 1.5 T in a continuous way. The temperature stability of the system is controlled to within ±10 mK and the standard range for the current setup is from 230 K to 330 K. The device is under high vacuum and we show that thermal losses to the ambient are negligible in terms of the calorimetric determination of the magnetic entropy change, while the losses cannot be ignored when correcting for the actual sample temperature. We apply the device to two different types of samples; one is commercial grade Gd, i.e., a pure second-order phase transition material, while the other is Gd5Si2Ge2, a first order magnetic phase transition material. We demonstrate the device’s ability to fully capture the thermal hysteresis of the latter sample by following appropriate thermal resetting scheme and magnetic resetting scheme.
Study on re-sputtering during CNx film deposition through spectroscopic diagnostics of plasma
Authors: Liang Peipei , Yang Xu , Li Hui , Cai Hua , Sun Jian , Xu Ning , Wu Jiada
Published: October 2015

A nitrogen-carbon plasma was generated during the deposition of carbon nitride (CNx) thin films by pulsed laser ablation of a graphite target in a discharge nitrogen plasma, and the optical emission of the generated nitrogen-carbon plasma was measured for the diagnostics of the plasma and the characterization of the process of CNx film deposition. The nitrogen-carbon plasma was recognized to contain various species including nitrogen molecules and molecular ions excited in the ambient N2 gas, carbon atoms and atomic ions ablated from the graphite target and CN radicals. The temporal evolution and spatial distribution of the CN emission and their dependence on the substrate bias voltage show two groups of CN radicals flying in opposite directions. One represents the CN radicals formed as the products of the reactions occurring in the nitrogen-carbon plasma, revealing the reactive deposition of CNx film due to the reactive expansion of the ablation carbon plasma in the discharge nitrogen plasma and the effective formation of gaseous CN radicals as precursors for CNx film growth. The other one represents the CN radicals re-sputtered from the growing CNx film by energetic plasma species, evidencing the re-sputtering of the growing film accompanying film growth. And, the re-sputtering presents ion-induced sputtering features.
Laboratory study of diffusion region with electron energization during high guide field reconnection
Authors: Yamasaki K. , Inoue S. , Kamio S. , Watanabe T. G. , Ushiki T. , Guo X. , Sugawara T. , Matsuyama K. , Kawakami N. , Yamada T. , Inomoto M. , Ono Y.
Published: October 2015

Floating potential profile was measured around the X-point during high guide field reconnection in UTST merging experiment where the ratio of guide field (Bg) to reconnecting magnetic field (Brec) is Bg/Brec>10. Floating potential measurement revealed that a quadrupole structure of electric potential is formed around the X-point during the fast reconnection phase due to the polarization by inductive electric field. Also, our floating potential measurement revealed the existence of parallel electric field in the vicinity of the X-point. While field-aligned components of inductive electric field (E∥ind) and electrostatic electric field (E∥es) cancel out with each other away from the X-point, E∥ind exceeds E∥es around the X-point, indicating the deviation from ideal MHD criterion within the region. The diffusion region extends in the outflow region and the scale length of region is an order of ion skin depth, which is quite different from the VTF experiment result. Based on the measured magnetic field and electric field profile, our particle trajectory analysis indicates that fast electrons with energies over 300 eV are produced within 1 μs around the X-point in the non-ideal MHD region. These results indicate that production of fast electrons or electron heating are expected to be observed in the vicinity of the X-point.
Sub-critical crack growth in silicate glasses: Role of network topology
Authors: Smedskjaer Morten M. , Bauchy Mathieu
Published: October 2015

The presence of water in the surrounding atmosphere can cause sub-critical crack growth (SCCG) in glasses, a phenomenon known as fatigue or stress corrosion. Here, to facilitate the compositional design of more fatigue-resistant glasses, we investigate the composition dependence of SCCG by studying fourteen silicate glasses. The fatigue curves (V-KI) have been obtained by indentation experiments through measurements of the crack length as a function of post-indentation fatigue duration. Interestingly, we find that the fatigue resistance parameter N is generally improved by increasing the alumina content and is thereby found to exhibit a fairly linear dependence on the measured Vickers hardness HV for a wide range of N and HV values. This finding highlights the important role of network topology in governing the SCCG in silicate glasses, since hardness has been shown to scale linearly with the number of atomic constraints. Our results therefore suggest that glasses showing under-constrained flexible networks, which feature floppy internal modes of deformation, are more readily attacked by water molecules, thus promoting stress corrosion and reducing the fatigue resistance.
Metallization and Hall-effect of Mg2Ge under high pressure
Authors: Li Yuqiang , Gao Yang , Han Yonghao , Liu Cailong , Peng Gang , Wang Qinglin , Ke Feng , Ma Yanzhang , Gao Chunxiao
Published: October 2015

The electrical transport properties of Mg2Ge under high pressure were studied with the in situ temperature-dependent resistivity and Hall-effect measurements. The theoretically predicted metallization of Mg2Ge was definitely found around 7.4 GPa by the temperature-dependent resistivity measurement. Other two pressure-induced structural phase transitions were also reflected by the measurements. Hall-effect measurement showed that the dominant charge carrier in the metallic Mg2Ge was hole, indicating the “bad metal” nature of Mg2Ge. The Hall mobility and charge carrier concentration results pointed out that the electrical transport behavior in the antifluorite phase was controlled by the increase quantity of drifting electrons under high pressure, but in both anticotunnite and Ni2In-type phases it was governed by the Hall mobility.
Influence of volume magnetostriction on the thermodynamic properties of Ni-Mn-Ga shape memory alloys
Authors: Kosogor Anna , L'vov Victor A. , Cesari Eduard
Published: October 2015

In the present article, the thermodynamic properties of Ni-Mn-Ga ferromagnetic shape memory alloys exhibiting the martensitic transformations (MTs) above and below Curie temperature are compared. It is shown that when MT goes below Curie temperature, the elastic and thermal properties of alloy noticeably depend on magnetization value due to spontaneous volume magnetostriction. However, the separation of magnetic parts from the basic characteristics of MT is a difficult task, because the volume magnetostriction does not qualitatively change the transformational behaviour of alloy. This problem is solved for several Ni-Mn-Ga alloys by means of the quantitative theoretical analysis of experimental data obtained in the course of stress-strain tests. For each alloy, the entropy change and the transformation heat evolved in the course of MT are evaluated, first, from the results of stress-strain tests and, second, from differential scanning calorimetry data. For all alloys, a quantitative agreement between the values obtained in two different ways is observed. It is shown that the magnetic part of transformation heat exceeds the non-magnetic one for the Ni-Mn-Ga alloys undergoing MTs in ferromagnetic state, while the elevated values of transformation heat measured for the alloys undergoing MTs in paramagnetic state are caused by large MT strains.
Thermally stable voltage-controlled perpendicular magnetic anisotropy in Mo|CoFeB|MgO structures
Authors: Li Xiang , Yu Guoqiang , Wu Hao , Ong P. V. , Wong Kin , Hu Qi , Ebrahimi Farbod , Upadhyaya Pramey , Akyol Mustafa , Kioussis Nicholas , Han Xiufeng , Khalili Amiri Pedram , Wang Kang L.
Published: October 2015

We study voltage-controlled magnetic anisotropy (VCMA) and other magnetic properties in annealed Mo|CoFeB|MgO layered structures. The interfacial perpendicular magnetic anisotropy (PMA) is observed to increase with annealing over the studied temperature range, and a VCMA coefficient of about 40 fJ/V-m is sustained after annealing at temperatures as high as 430 °C. Ab initio electronic structure calculations of interfacial PMA as a function of strain further show that strain relaxation may lead to the increase of interfacial PMA at higher annealing temperatures. Measurements also show that there is no significant VCMA and interfacial PMA dependence on the CoFeB thickness over the studied range, which illustrates the interfacial origin of the anisotropy and its voltage dependence, i.e., the VCMA effect. The high thermal annealing stability of Mo|CoFeB|MgO structures makes them compatible with advanced CMOS back-end-of-line processes, and will be important for integration of magnetoelectric random access memory into on-chip embedded applications.
Cesium hafnium chloride: A high light yield, non-hygroscopic cubic crystal scintillator for gamma spectroscopy
Authors: Burger Arnold , Rowe Emmanuel , Groza Michael , Morales Figueroa Kristle , Cherepy Nerine J. , Beck Patrick R. , Hunter Steven , Payne Stephen A.
Published: October 2015

We report on the scintillation properties of Cs2HfCl6 (cesium hafnium chloride or CHC) as an example of a little-known class of non-hygroscopic compounds having the generic cubic crystal structure of K2PtCl6. The crystals are easily growable from the melt using the Bridgman method with minimal precursor treatments or purification. CHC scintillation is centered at 400 nm, with a principal decay time of 4.37 μs and a light yield of up to 54 000 photons/MeV when measured using a silicon CCD photodetector. The light yield is the highest ever reported for an undoped crystal, and CHC also exhibits excellent light yield nonproportionality. These desirable properties allowed us to build and test CHC gamma-ray spectrometers providing energy resolution of 3.3% at 662 keV.
Analysis of lasers as a solution to efficiency droop in solid-state lighting
Authors: Chow W. W. , Crawford M. H.
Published: October 2015

This letter analyzes the proposal to mitigate the efficiency droop in solid-state light emitters by replacing InGaN light-emitting diodes (LEDs) with lasers. The argument in favor of this approach is that carrier-population clamping after the onset of lasing limits carrier loss to that at threshold, while stimulated emission continues to grow with injection current. A fully quantized (carriers and light) theory that is applicable to LEDs and lasers (above and below threshold) is used to obtain a quantitative evaluation. The results confirm the potential advantage of higher laser output power and efficiency above lasing threshold, while also indicating disadvantages including low efficiency prior to lasing onset, sensitivity of lasing threshold to temperature, and the effects of catastrophic laser failure. A solution to some of these concerns is suggested that takes advantage of recent developments in nanolasers.
Boundary layer flow and heat transfer to Carreau fluid over a nonlinear stretching sheet
Authors: Khan Masood , Hashim
Published: October 2015

This article studies the Carreau viscosity model (which is a generalized Newtonian model) and then use it to obtain a formulation for the boundary layer equations of the Carreau fluid. The boundary layer flow and heat transfer to a Carreau model over a nonlinear stretching surface is discussed. The Carreau model, adequate for many non-Newtonian fluids, is used to characterize the behavior of the fluids having shear thinning properties and fluids with shear thickening properties for numerical values of the power law exponent n. The modeled boundary layer conservation equations are converted to non-linear coupled ordinary differential equations by a suitable transformation. Numerical solution of the resulting equations are obtained by using the Runge-Kutta Fehlberg method along with shooting technique. This analysis reveals many important physical aspects of flow and heat transfer. Computations are performed for different values of the stretching parameter (m), the Weissenberg number (We) and the Prandtl number (Pr). The obtained results show that for shear thinning fluid the fluid velocity is depressed by the Weissenberg number while opposite behavior for the shear thickening fluid is observed. A comparison with previously published data in limiting cases is performed and they are in excellent agreement.
Ultraviolet nanoimprint lithography using cyclodextrin-based porous template for pattern failure reduction
Authors: Takei Satoshi , Hanabata Makoto
Published: October 2015

An approach to ultraviolet (UV) nanoimprint lithography using a cyclodextrin-based porous template was investigated for the reduction of air trapping and template damage caused by gases such as nitrogen and oxygen generated from UV cross-linked materials. The accuracy of the printed pattern using UV nanoimprint lithography with the porous transparent template was improved because of enhanced material adsorption and increased permeability to gaseous species. The use of volatile solvents in the UV cross-linked materials for nanoimprint lithography has been limited because of high pattern failure rates. However, using the cyclodextrin-based porous template, the UV cross-linked materials with a 5 wt. % volatile solvent exhibited well-defined nanoscale patterns. Based on this study, acceptable chemistries for the UV cross-linked materials have been expanded, which will be beneficial for future device applications using UV nanoimprint lithography.
Strongly transverse-electric-polarized emission from deep ultraviolet AlGaN quantum well light emitting diodes
Authors: Reich Christoph , Guttmann Martin , Feneberg Martin , Wernicke Tim , Mehnke Frank , Kuhn Christian , Rass Jens , Lapeyrade Mickael , Einfeldt Sven , Knauer Arne , Kueller Viola , Weyers Markus , Goldhahn Rüdiger , Kneissl Michael
Published: October 2015

The optical polarization of emission from ultraviolet (UV) light emitting diodes (LEDs) based on (0001)-oriented AlxGa1−xN multiple quantum wells (MQWs) has been studied by simulations and electroluminescence measurements. With increasing aluminum mole fraction in the quantum well x, the in-plane intensity of transverse-electric (TE) polarized light decreases relative to that of the transverse-magnetic polarized light, attributed to a reordering of the valence bands in AlxGa1−xN. Using k ⋅ p theoretical model calculations, the AlGaN MQW active region design has been optimized, yielding increased TE polarization and thus higher extraction efficiency for bottom-emitting LEDs in the deep UV spectral range. Using (i) narrow quantum wells, (ii) barriers with high aluminum mole fractions, and (iii) compressive growth on patterned aluminum nitride sapphire templates, strongly TE-polarized emission was observed at wavelengths as short as 239 nm.
Note: Dissolved hydrogen detection in power transformer oil based on chemically etched fiber Bragg grating
Authors: Jiang Jun , Ma Guo-ming , Song Hong-tu , Zhou Hong-yang , Li Cheng-rong , Luo Ying-ting , Wang Hong-bin
Published: October 2015

A fiber Bragg grating (FBG) sensor based on chemically etched cladding to detect dissolved hydrogen is proposed and studied in this paper. Low hydrogen concentration tests have been carried out in mixed gases and transformer oil to investigate the repeatability and sensitivity. Moreover, to estimate the influence of etched cladding thickness, a physical model of FBG-based hydrogen sensor is analyzed. Experimental results prove that thin cladding chemically etched by HF acid solution improves the response to hydrogen detection in oil effectively. At last, the sensitivity of FBG sensor chemically etched 16 μm could be as high as 0.060 pm/(μl/l), increased by more than 30% in comparison to un-etched FBG.
Metal speciation from stream to open ocean: modelling v. measurement
Authors: Tipping Edward , Lofts Stephen , Stockdale Anthony
Published: October 2015

Environmental contextThe chemical speciation of metals strongly influences their transport, fate and bioavailability in natural waters. Analytical measurement and modelling both play important roles in understanding speciation, while modelling is also needed for prediction. Here, we analyse a large set of data for fresh waters, estuarine and coastal waters, and open ocean water, to examine how well measurements and modelling predictions agree.
AbstractWe compiled a data set of ~2000 published metal speciation measurements made on samples of fresh waters, estuarine and coastal waters, and open ocean waters. For each sample, we applied the chemical speciation model WHAM7 to calculate the equilibrium free metal ion concentrations, [M] (molL–1), amounts of metal bound by dissolved organic matter (DOM), ν (molg–1), and their ratio ν/[M] (L g–1), which is a kind of ‘local’ partition coefficient. Comparison of the measured and predicted speciation variables for the whole data set showed that agreements are best for fresh waters, followed by estuarine and coastal waters, then open-ocean waters. Predicted values of ν/[M], averaged over all results for each metal, closely follow the trend in average measured values, confirming that metal reactivity, and consequent complexation by DOM, in natural waters accord with the expectations of the speciation model. Comparison of model predictions with measurements by different analytical techniques suggests that competitive ligand–stripping voltammetry methods overestimate metal complexation by DOM, and therefore underestimate [M]. When measurements by other methods are compared with predictions, for all metals, reasonable agreement with little bias is obtained at values of ν>10–6molg–1 DOM, but at lower values of ν, the model predictions of [M] are mostly higher than the measured values, and the predictions of ν and ν/[M] are mostly lower. Research is needed to establish whether this reflects analytical error or the failure of the model to represent natural high-affinity ligands.
The potential effects of anthropogenic climate change on evaporation from water storage reservoirs within the Lockyer Catchment, south-east Queensland, Australia
Authors: McGloin Ryan , McGowan Hamish , McJannet David
Published: October 2015

In order to effectively manage water storage reservoirs, it is essential to be able to anticipate how components of the water balance will react to predicted long-term trends in climate. This study examines the potential impacts of anthropogenic climate change on evaporation from small reservoirs in the Lockyer catchment, a productive agricultural region in south-east Queensland, Australia. Future projections of evaporation, made using the most likely future emissions scenario, suggested that evaporation is expected to increase by ~6% by the year 2050. In addition, rainfall is expected to decrease by ~8%. These projected increases in evaporation and reductions in rainfall, combined with the knowledge that changes in annual rainfall are known to be amplified in annual runoff, mean that the availability of water resources in the Lockyer catchment region may be greatly diminished in the future. In addition, increases in water scarcity, combined with higher future air temperatures and population growth, are likely to result in a greater demand for irrigation in the future.
Modulation of embryonic development due to mating with immunised males
Authors: Gerlinskaya Ludmila A. , Maslennikova Svetlana O. , Anisimova Margaret V. , Feofanova Nataly A. , Zavjalov Evgenii L. , Kontsevaya Galina V. , Moshkin Yuri M. , Moshkin Mikhail P.
Published: October 2015

The modification of pre- and postnatal development conferred by immunogenic stimulation of mothers provides a population-level adaptation mechanism for non-genetic transfer of maternal experiences to progeny. However little is known about the transmission of paternal immune experiences to offspring. Here, we show that immune priming of males 3–9 days before mating affects the growth and humoral environment of developing embryos of outbred (ICR) and inbred (C57BL and BALB/c) mice. Antigenic stimulation of fathers caused a significant increase in embryonic bodyweight as measured on Day 16 of pregnancy and altered other gestation parameters, such as feto–placental ratio. Pregnant females mated with immunised males were also characterised by changes in humoral conditions as shown by measurements of blood and amniotic progesterone, testosterone and granulocyte–macrophage colony-stimulating factor (GM-CSF) cytokine concentrations. These results emphasise the role of paternal effects of immune priming on the in utero environment and fetal growth.
Medieval warming initiated exceptionally large wildfire outbreaks in the Rocky Mountains
Authors: Calder W. John , Parker Dusty , Stopka Cody J. , Jiménez-Moreno Gonzalo , Shuman Bryan N.
Published: October 2015

Significance

In the western United States and other forested regions, climate change may increase both the frequency of wildfires and the amount of area burned. Studies of past climate changes and their effects on wildfires can provide constraints on potential future wildfire risks. Here, we reconstruct the history of wildfire across a representative subalpine forest landscape in northern Colorado over the past two millennia. Warming of ∼0.5 °C ∼1,000 years ago increased the percentage of our study sites burned per century by ∼260% relative to the past ∼400 y. The large increase in the number of sites burned by fires highlights the risk that large portions of individual landscapes may burn as climates continue to warm today.
Current extinction rates of reptiles and amphibians
Authors: Alroy John
Published: October 2015

Significance

It is hard to know how many species have gone extinct so far because it is difficult to prove that something not seen recently is really gone forever. This paper uses a new, highly conservative statistical method to infer the number of extinct amphibian and reptile species across the world. Frogs are of particular concern because an invasive fungus has recently caused many populations to collapse. The data are lists of specimens in museum collections. The method provides sensible results when the data are randomized or artificial extinctions are imposed. It suggests that about 200 frog extinctions have occurred and hundreds more will be lost over the next century, so we are on pace to create a mass extinction.
Population genomic structure and adaptation in the zoonotic malaria parasite
Plasmodium knowlesi
Authors: Assefa Samuel , Lim Caeul , Preston Mark D. , Duffy Craig W. , Nair Mridul B. , Adroub Sabir A. , Kadir Khamisah A. , Goldberg Jonathan M. , Neafsey Daniel E. , Divis Paul , Clark Taane G. , Duraisingh Manoj T. , Conway David J. , Pain Arnab , Singh Balbir
Published: October 2015

Significance

Genome sequence analysis reveals that the zoonotic malaria parasite
Plasmodium knowlesi
consists of three highly divergent subpopulations. Two, commonly seen in sympatric human clinical infections in Malaysian Borneo, were identified in a previous study as corresponding to parasites seen in long-tailed and pig-tailed macaque hosts, respectively. A third type has been detected in a few laboratory-maintained isolates originally derived in the 1960s elsewhere in Southeast Asia. Divergence between the subpopulations varies significantly across the genome but overall is at a level indicating different subspecies. Analysis of the diversity within the most common type in human infections shows strong signatures of natural selection, including balancing selection and directional selection, on loci distinct from those under selection in endemic human malaria parasites.
Brain palpation from physiological vibrations using MRI
Authors: Zorgani Ali , Souchon Rémi , Dinh Au-Hoang , Chapelon Jean-Yves , Ménager Jean-Michel , Lounis Samir , Rouvière Olivier , Catheline Stefan
Published: October 2015

Significance

It is commonly supposed that noise obscures but does not contain useful information. However, in wave physics and especially, seismology, scientists developed some tools known as “noise correlation” to extract useful information and construct images from the random vibrations of a medium. Living tissues are full of unexploited vibrations as well. In this manuscript, we show that noise correlation techniques in the brain using MRI can conduct to a tomography related to the stiffness that physicians estimate during a palpation examination. This MRI brain seismology in rupture with other techniques is experimentally shown in vitro and in vivo.
Longitudinal spread of mechanical excitation through tectorial membrane traveling waves
Authors: Sellon Jonathan B. , Farrahi Shirin , Ghaffari Roozbeh , Freeman Dennis M.
Published: October 2015

Significance

The sharp frequency selectivity of auditory neurons, which is a hallmark of mammalian hearing, originates mechanically in the cochlea. Local resonance of the tectorial membrane (TM) is thought to play a key role. However, the presence of TM traveling waves suggests an entirely different mechanism. In this paper, we present experiments to measure longitudinal spread of mechanical excitation via TM traveling waves and discuss implications for the resulting tuning. We show that increasing viscosity or decreasing stiffness of the TM reduces the longitudinal spread of mechanical excitation, which would sharpen frequency selectivity. These trends are opposite those trends for a resonant TM, where increasing viscous loss or decreasing stiffness would broaden tuning.
Dissecting pigment architecture of individual photosynthetic antenna complexes in solution
Authors: Wang Quan , Moerner W. E.
Published: October 2015

Significance

Energy from the sun is captured by the biosphere through photosynthetic antenna proteins, which function by integration of a set of pigments into a protein scaffold. Nature uses relatively similar pigment building blocks to achieve diverse functions, and the organizing principles behind this process are not fully understood. Using a single-molecule microfluidic trap and multiparameter fluorescence spectroscopy, we explore how the photophysical properties of individual pigment sites are modulated by the protein’s oligomerization states, using single proteins of a model antenna from cyanobacteria. Our measurements achieve a bottom-up dissection of the structural-function relation of the model pigment−protein complex with important implications for photosynthetic antenna biophysics.
Indoleamine 2,3-dioxygenase-1 is protective in atherosclerosis and its metabolites provide new opportunities for drug development
Authors: Cole Jennifer E. , Astola Nagore , Cribbs Adam P. , Goddard Michael E. , Park Inhye , Green Patricia , Davies Alun H. , Williams Richard O. , Feldmann Marc , Monaco Claudia
Published: October 2015

Significance

Inflammation is an important component of the pathogenesis of cardiovascular disease, the world’s biggest killer. No antiinflammatory treatments have yet been developed to treat cardiovascular disease. Indoleamine 2,3-dioxygenase (IDO) is a critical enzyme in the metabolism of tryptophan that has been shown to be immune-regulatory in many diseases. ApoE−/−mice deficient in IDO (ApoE−/−Indo−/−) developed larger atherosclerotic lesions and an unfavorable lesion phenotype that may predispose to cardiovascular complications. Furthermore, administration of an orally active synthetic tryptophan metabolite (3,4-DAA) reduced disease development in mice and cytokine production in human atheroma. Our data demonstrate that endogenous production of tryptophan metabolites via IDO is an essential feedback loop that controls atherogenesis and athero-inflammation, defining a path toward the development of new therapeutics.
Shocking Results: Assessing the Rates of Fish Injury from Pulsed-DC Electrofishing
Authors: Culver Edward F. , Chick John H.
Published: October 2015

Electrofishing is one of the more commonly used techniques for sampling fish in freshwater ecosystems. In the present study, four native fish species (Bluegill Lepomis macrochirus, Channel Catfish Ictalurus punctatus, Freshwater Drum Aplodinotus grunniens, and Gizzard Shad Dorosoma cepedianum) and two invasive species (Common Carp Cyprinus carpio and Silver Carp Hypophthalmichthys molitrix) that were captured in the Mississippi and Illinois rivers were assessed for evidence of vertebral injuries from pulsed-DC (PDC) boat electrofishing. Fish were collected by electrofishing crews conducting routine standardized sampling for two long-term monitoring programs. Fifty percent of Silver Carp and 27% of Channel Catfish were injured; no injuries were observed for the other species examined. Injury rates for Silver Carp were 71% in the Illinois River and 30% in the Mississippi River. The Silver Carp injury rate was positively correlated with conductivity, temperature, and pulse frequency and negatively correlated with TL. In contrast, the injury rate of Channel Catfish was similar between rivers and exhibited no correlation with TL, condition factor, conductivity, or temperature. Our results demonstrate that Silver Carp and Channel Catfish in the upper Mississippi River system are sustaining injuries from PDC electrofishing. The observed effects of pulse frequency on the Silver Carp injury rate suggest that managers could alter the pulse frequency settings for the electric barriers at the Chicago Sanitary and Ship Canal and for other electricity-based management efforts to reduce Silver Carp populations in the Chicago Area Waterway System.

Received March 25, 2015; accepted July 6, 2015
The Eurozone crisis and Italian corporate governance: the end of blockholding?
Authors: Bulfone Fabio
Published: October 2015

This article explains the process of change in domestic corporate governance. An actor-centred coalitional approach is applied to the Italian case to show how the main features of domestic corporate governance are a product of behavioural patterns (i.e. informal institutions), rather than formal legislation. Leveraging their superior financial means, business elites act as institutional incumbents shaping these informal institutions according to their preferences. It is argued that a change in corporate practices is more likely to be triggered by a socio-economic crisis, which weakens the domestic elite's influence, rather than a legal reform. These findings call into question the excessively formalistic approach of many corporate governance scholars, and are confirmed by the Italian trajectory. After having resisted 20 years of liberalising legal reforms aimed at eroding their power, Italian blockholders are now being forced, as a consequence of the Eurozone sovereign debt crisis, to dismantle their cross-shareholding networks.
RanGTP aids anaphase entry through Ubr5-mediated protein turnover
Authors: Jiang Hao , He Xiaonan , Feng Di , Zhu Xueliang , Zheng Yixian
Published: October 2015

RanGTP is known to regulate the spindle assembly checkpoint (SAC), but the underlying molecular mechanism is unclear. BuGZ stabilizes SAC protein Bub3 through direct interaction and facilitates its mitotic function. Here we show that RanGTP promotes the turnover of BuGZ and Bub3 in metaphase, which in turn facilitates metaphase-to-anaphase transition. BuGZ and Bub3 interact with either importin-β or an E3 ubiquitin ligase, Ubr5. RanGTP promotes the dissociation of importin-β from BuGZ and Bub3 in metaphase. This results in increased binding of BuGZ and Bub3 to Ubr5, leading to ubiquitination and subsequent turnover of both proteins. We propose that elevated metaphase RanGTP levels use Ubr5 to couple overall chromosome congression to SAC silencing.
The role of group IIF-secreted phospholipase A2 in epidermal homeostasis and hyperplasia
Authors: Yamamoto Kei , Miki Yoshimi , Sato Mariko , Taketomi Yoshitaka , Nishito Yasumasa , Taya Choji , Muramatsu Kazuaki , Ikeda Kazutaka , Nakanishi Hiroki , Taguchi Ryo , Kambe Naotomo , Kabashima Kenji , Lambeau Gérard , Gelb Michael H. , Murakami Makoto
Published: October 2015

Epidermal lipids are important for skin homeostasis. However, the entire picture of the roles of lipids, particularly nonceramide lipid species, in epidermal biology still remains obscure. Here, we report that PLA2G2F, a functionally orphan-secreted phospholipase A2 expressed in the suprabasal epidermis, regulates skin homeostasis and hyperplasic disorders. Pla2g2f−/− mice had a fragile stratum corneum and were strikingly protected from psoriasis, contact dermatitis, and skin cancer. Conversely, Pla2g2f-overexpressing transgenic mice displayed psoriasis-like epidermal hyperplasia. Primary keratinocytes from Pla2g2f−/− mice showed defective differentiation and activation. PLA2G2F was induced by calcium or IL-22 in keratinocytes and preferentially hydrolyzed ethanolamine plasmalogen-bearing docosahexaenoic acid secreted from keratinocytes to give rise to unique bioactive lipids (i.e., protectin D1 and 9S-hydroxyoctadecadienoic acid) that were distinct from canonical arachidonate metabolites (prostaglandins and leukotrienes). Ethanolamine lysoplasmalogen, a PLA2G2F-derived marker product, rescued defective activation of Pla2g2f−/− keratinocytes both in vitro and in vivo. Our results highlight PLA2G2F as a previously unrecognized regulator of skin pathophysiology and point to this enzyme as a novel drug target for epidermal-hyperplasic diseases.
Resolvin E1 inhibits dendritic cell migration in the skin and attenuates contact hypersensitivity responses
Authors: Sawada Yu , Honda Tetsuya , Hanakawa Sho , Nakamizo Satoshi , Murata Teruasa , Ueharaguchi-Tanada Yuri , Ono Sachiko , Amano Wataru , Nakajima Saeko , Egawa Gyohei , Tanizaki Hideaki , Otsuka Atsushi , Kitoh Akihiko , Dainichi Teruki , Ogawa Narihito , Kobayashi Yuichi , Yokomizo Takehiko , Arita Makoto , Nakamura Motonobu , Miyachi Yoshiki , Kabashima Kenji
Published: October 2015

Resolvin E1 (RvE1) is a lipid mediator derived from ω3 polyunsaturated fatty acids that exerts potent antiinflammatory roles in several murine models. The antiinflammatory mechanism of RvE1 in acquired immune responses has been attributed to attenuation of cytokine production by dendritic cells (DCs). In this study, we newly investigated the effect of RvE1 on DC motility using two-photon microscopy in a contact hypersensitivity (CHS) model and found that RvE1 impaired DC motility in the skin. In addition, RvE1 attenuated T cell priming in the draining lymph nodes and effector T cell activation in the skin, which led to the reduced skin inflammation in CHS. In contrast, leukotriene B4 (LTB4) induced actin filament reorganization in DCs and increased DC motility by activating Cdc42 and Rac1 via BLT1, which was abrogated by RvE1. Collectively, our results suggest that RvE1 attenuates cutaneous acquired immune responses by inhibiting cutaneous DC motility, possibly through LTB4-BLT1 signaling blockade.
Matchings in Benjamini–Schramm convergent graph sequences
Authors: Abért Miklós , Csikvári Péter , Frenkel Péter , Kun Gábor
Published: October 2015

We introduce the matching measure of a finite graph as the uniform distribution on the roots of the matching polynomial of the graph. We analyze the asymptotic behavior of the matching measure for graph sequences with bounded degree.

A graph parameter is said to be estimable if it converges along every Benjamini–Schramm convergent sparse graph sequence. We prove that the normalized logarithm of the number of matchings is estimable. We also show that the analogous statement for perfect matchings already fails for

d
d

–regular bipartite graphs for any fixed

d
≥
3

d\ge 3

. The latter result relies on analyzing the probability that a randomly chosen perfect matching contains a particular edge.

However, for any sequence of

d
d

–regular bipartite graphs converging to the

d
d

–regular tree, we prove that the normalized logarithm of the number of perfect matchings converges. This applies to random

d
d

–regular bipartite graphs. We show that the limit equals the exponent in Schrijver’s lower bound on the number of perfect matchings.

Our analytic approach also yields a short proof for the Nguyen–Onak (also Elek–Lippner) theorem saying that the matching ratio is estimable. In fact, we prove the slightly stronger result that the independence ratio is estimable for claw-free graphs.
Physical Activity and Body Weight among Adults in Malaysia
Authors: Tan Andrew K. G. , Wang Yanghao , Yen Steven T. , Feisul Mustapha I.
Published: October 2015

The influence of sociodemographic and lifestyle factors on body weight conditional upon endogenous physical activity (PA) is examined for adults in Malaysia. We find an inverse link between body weight and PA at elevated PA levels. Vigorous PA with metabolic equivalent of task (MET) of 1500 minutes per week and above is required for healthy changes in body weight. Older individuals and those with low education and a family history of illnesses are associated with higher body mass index (BMI) across PA levels. Individuals of Chinese and other ethnicity, males, smokers, and persons working long hours have lower BMI at all PA levels.
Streptobacillus notomytis sp. nov., isolated from a spinifex hopping mouse (Notomys alexis Thomas, 1922), and emended description of Streptobacillus Levaditi et al. 1925, Eisenberg et al. 2015 emend.
Authors: Eisenberg Tobias , Glaeser Stefanie P. , Ewers Christa , Semmler Torsten , Nicklas Werner , Rau Jörg , Mauder Norman , Hofmann Nicola , Imaoka Koichi , Kimura Masanobu , Kämpfer Peter
Published: October 2015

A pleomorphic, Gram-negative, rod-shaped, indole-, oxidase- and catalase-negative, non-spore-forming, non-motile bacterium was isolated in 1979 from the heart of a spinifex hopping mouse (Notomys alexis Thomas, 1922) with septicaemia and stored as Streptobacillus moniliformis in the strain collection of the Animal Health Laboratory, South Perth, Western Australia (AHL 370-1), as well as under CCUG 12425. On the basis of 16S rRNA gene sequence analyses, the strain was assigned to the genus Streptobacillus, with 99.4 % sequence similarity to the type strain of Streptobacillus moniliformis, 95.6 % sequence similarity to the type strain of Streptobacillus hongkongensis and 99.0 % sequence similarity to the type strain of Streptobacillus felis. The clear differentiation of strain AHL 370-1T from Streptobacillus moniliformis, Streptobacillus hongkongensis and Streptobacillus felis was also supported by rpoB, groEL and recA nucleotide and amino acid sequence analysis. Average nucleotide identity was 87.16 % between strain AHL 370-1T and Streptobacillus moniliformis DSM 12112T. Physiological data confirmed the allocation of strain AHL 370-1T to the family Leptotrichiaceae, considering the very similar profiles of enzyme activities and fatty acids compared to closely related species. Within the genus Streptobacillus, isolate AHL 370-1T could also be separated unambiguously from the type strains of Streptobacillus moniliformis, Streptobacillus hongkongensis and Streptobacillus felis by MALDI-TOF mass spectrometry. Two further strains (KWG2 and KWG24) isolated from asymptomatic black rats in Japan were highly similar to AHL 370-1T. On the basis of these data, we propose the novel species Streptobacillus notomytis sp. nov., with the type strain AHL 370-1T ( = CCUG 12425T = DSM 100026T = CCM 8593T = EF 12425T).
Marinobacter confluentis sp. nov., a lipolytic bacterium isolated from a junction between the ocean and a freshwater lake
Authors: Park Sooyeon , Kim Sona , Kang Chul-Hyung , Jung Yong-Taek , Yoon Jung-Hoon
Published: October 2015

A Gram-stain-negative, motile, aerobic and rod-shaped bacterium, designated HJM-18T, was isolated from the place where the ocean and a freshwater lake meet at Hwajinpo, South Korea, and subjected to a taxonomic study using a polyphasic approach. Strain HJM-18T grew optimally at 30 °C, at pH 7.0–8.0 and in the presence of 1.0–3.0 % (w/v) NaCl. Phylogenetic trees based on 16S rRNA gene sequences showed that strain HJM-18T belonged to the genus Marinobacter. Strain HJM-18T exhibited 16S rRNA gene sequence similarity values of 97.05–98.22 % to the type strains of Marinobacter algicola, Marinobacter flavimaris, Marinobacter adhaerens, Marinobacter salarius, Marinobacter salsuginis, Marinobacter guineae and Marinobacter gudaonensis and of 93.21–96.98 % to the type strains of the other species of the genus Marinobacter. Strain HJM-18T contained Q-9 as the predominant ubiquinone and summed feature 3 (C16 : 1ω7c and/or C16 : 1ω6c), C16 : 0 and C18 : 1ω9c as the major fatty acids. The major polar lipids detected in strain HJM-18T were phosphatidylethanolamine, phosphatidylglycerol and one unidentified aminophospholipid. The DNA G+C content was 58 mol% and the mean DNA–DNA relatedness values with the type strains of the seven phylogenetically related species of the genus Marinobacter were 10–27 %. Differential phenotypic properties, together with phylogenetic and genetic distinctiveness, revealed that strain HJM-18T is separated from recognized species of the genus Marinobacter. On the basis of the data presented, strain HJM-18T represents a novel species of the genus Marinobacter, for which the name Marinobacter confluentis sp. nov. is proposed. The type strain is HJM-18T ( = KCTC 42705T = NBRC 111223T).