bluuebunny/crossref_metadata_2025 huggingface dataset:
Sidewall passivation for InGaN/GaN nanopillar light emitting diodes
Authors: Choi Won Hyuck , You Guanjun , Abraham Michael , Yu Shih-Ying , Liu Jie , Wang Li , Xu Jian , Mohney Suzanne E.
Published: July 2014

We studied the effect of sidewall passivation on InGaN/GaN multiquantum well-based nanopillar light emitting diode (LED) performance. In this research, the effects of varying etch rate, KOH treatment, and sulfur passivation were studied for reducing nanopillar sidewall damage and improving device efficiency. Nanopillars prepared under optimal etching conditions showed higher photoluminescence intensity compared with starting planar epilayers. Furthermore, nanopillar LEDs with and without sulfur passivation were compared through electrical and optical characterization. Suppressed leakage current under reverse bias and four times higher electroluminescence (EL) intensity were observed for passivated nanopillar LEDs compared with unpassivated nanopillar LEDs. The suppressed leakage current and EL intensity enhancement reflect the reduction of non-radiative recombination at the nanopillar sidewalls. In addition, the effect of sulfur passivation was found to be very stable, and further insight into its mechanism was gained through transmission electron microscopy.
Electron acoustic wave driven vortices with non-Maxwellian hot electrons in magnetoplasmas
Authors: Haque Q. , Mirza Arshad M. , Zakir U.
Published: July 2014

Linear dispersion characteristics of the Electron Acoustic Wave (EAW) and the corresponding vortex structures are investigated in a magnetoplasma in the presence of non-Maxwellian hot electrons. In this regard, kappa and Cairns distributed hot electrons are considered. It is noticed that the nonthermal distributions affect the phase velocity of the EAW. Further, it is found that the phase velocity of EAW increases for Cairns and decreases for kappa distributed hot electrons. Nonlinear solutions in the form of dipolar vortices are also obtained for both stationary and non-stationary ions in the presence of kappa distributed hot electrons and dynamic cold electrons. It is found that the amplitude of the nonlinear vortex structures also reduces with kappa factor like the electron acoustic solitons.
Self-pulsing of hollow cathode discharge in various gases
Authors: Qin Y. , He F. , Jiang X. X. , Xie K. , Ouyang J. T.
Published: July 2014

In this paper, we investigate the self-pulsing phenomenon of cavity discharge in a cylindrical hollow cathode in various gases including argon, helium, nitrogen, oxygen, and air. The current-voltage characteristics of the cavity discharge, the waveforms of the self-pulsing current and voltage as well as the repetition frequency were measured. The results show that the pulsing frequency ranges from a few to tens kilohertz and depends on the averaged current and the pressure in all gases. The pulsing frequency will increase with the averaged current and decrease with the pressure. The rising time of the current pulse is nearly constant in a given gas or mixture. The self-pulsing does not depend on the external ballast but is affected significantly by the external capacitor in parallel with the discharge cell. The low-current self-pulsing in hollow cathode discharge is the mode transition between Townsend and glow discharges. It can be described by the charging-discharging process of an equivalent circuit consisting of capacitors and resistors.
Time of flight emission spectroscopy of laser produced nickel plasma: Short-pulse and ultrafast excitations
Authors: Smijesh N. , Chandrasekharan K. , Joshi Jagdish C. , Philip Reji
Published: July 2014

We report the experimental investigation and comparison of the temporal features of short-pulse (7 ns) and ultrafast (100 fs) laser produced plasmas generated from a solid nickel target, expanding into a nitrogen background. When the ambient pressure is varied in a large range of 10−6 Torr to 102 Torr, the plume intensity is found to increase rapidly as the pressure crosses 1 Torr. Time of flight (TOF) spectroscopy of emission from neutral nickel (Ni I) at 361.9 nm (3d9(2D) 4p → 3d9(2D) 4s transition) reveals two peaks (fast and slow species) in short-pulse excitation and a single peak in ultrafast excitation. The fast and slow peaks represent recombined neutrals and un-ionized neutrals, respectively. TOF emission from singly ionized nickel (Ni II) studied using the 428.5 nm (3p63d8(3P) 4s→ 3p63d9 4s) transition shows only a single peak for either excitation. Velocities of the neutral and ionic species are determined from TOF measurements carried out at different positions (i.e., at distances of 2 mm and 4 mm, respectively, from the target surface) on the plume axis. Measured velocities indicate acceleration of neutrals and ions, which is caused by the Coulomb pull of the electrons enveloping the plume front in the case of ultrafast excitation. Both Coulomb pull and laser-plasma interaction contribute to the acceleration in the case of short-pulse excitation. These investigations provide new information on the pressure dependent temporal behavior of nickel plasmas produced by short-pulse and ultrafast laser pulses, which have potential uses in applications such as pulsed laser deposition and laser-induced nanoparticle generation.
Tuning electron transport through a single molecular junction by bridge modification
Authors: Li Xiao-Fei , Qiu Qi , Luo Yi
Published: July 2014

The possibility of controlling electron transport in a single molecular junction represents the ultimate goal of molecular electronics. Here, we report that the modification of bridging group makes it possible to improve the performance and obtain new functions in a single cross-conjugated molecular junction, designed from a recently synthesized bipolar molecule bithiophene naphthalene diimide. Our first principles results show that the bipolar characteristic remains after the molecule was modified and sandwiched between two metal electrodes. Rectifying is the intrinsic characteristic of the molecular junction and its performance can be enhanced by replacing the saturated bridging group with an unsaturated group. A further improvement of the rectifying and a robust negative differential resistance (NDR) behavior can be achieved by the modification of unsaturated bridge. It is revealed that the modification can induce a deviation angle about 4° between the donor and the acceptor π-conjugations, making it possible to enhance the communication between the two π systems. Meanwhile, the low energy frontier orbitals of the junction can move close to the Fermi level and encounter in energy at certain biases, thus a transport channel with a considerable transmission can be formed near the Fermi level only at a narrow bias regime, resulting in the improvement of rectifying and the robust NDR behavior. This finding could be useful for the design of single molecular devices.
Effects of erectable glossal hairs on a honeybee's nectar-drinking strategy
Authors: Yang Heng , Wu Jianing , Yan Shaoze
Published: July 2014

With the use of a scanning electron microscope, we observe specific microstructures of the mouthpart of the Italian bee (Apis mellifera ligustica), especially the distribution and dimensions of hairs on its glossa. Considering the erection of glossal hairs for trapping nectar modifies the viscous dipping model in analyzing the drinking strategy of a honeybee. Theoretical estimations of volume intake rates with respect to sucrose solutions of different concentrations agree with experimental data, which indicates that erectable hairs can significantly increase the ability of a bee to acquire nectar efficiently. The comparison with experimental results also indicates that a honeybee may continuously augment its pumping power, rather than keep it constant, to drink nectar with sharply increasing viscosity. Under the modified assumption of increasing working power, we introduce the rate at which working power increases with viscosity and discuss the nature-preferred nectar concentration of 35% by theoretically calculating optimal concentration maximizing energetic intake rates under varying increasing rates. Finally, the ability of the mouthparts of the honeybee to transfer viscous nectar may inspire a concept for transporting microfluidics with a wide range of viscosities.
Filamentary structures in dense plasma focus: Current filaments or vortex filaments?
Authors: Soto Leopoldo , Pavez Cristian , Castillo Fermin , Veloso Felipe , Moreno José , Auluck S. K. H.
Published: July 2014

Recent observations of an azimuthally distributed array of sub-millimeter size sources of fusion protons and correlation between extreme ultraviolet (XUV) images of filaments with neutron yield in PF-1000 plasma focus have re-kindled interest in their significance. These filaments have been described variously in literature as current filaments and vortex filaments, with very little experimental evidence in support of either nomenclature. This paper provides, for the first time, experimental observations of filaments on a table-top plasma focus device using three techniques: framing photography of visible self-luminosity from the plasma, schlieren photography, and interferometry. Quantitative evaluation of density profile of filaments from interferometry reveals that their radius closely agrees with the collision-less ion skin depth. This is a signature of relaxed state of a Hall fluid, which has significant mass flow with equipartition between kinetic and magnetic energy, supporting the “vortex filament” description. This interpretation is consistent with empirical evidence of an efficient energy concentration mechanism inferred from nuclear reaction yields.
Separation of surface accumulation and bulk neutral channel in junctionless transistors
Authors: Jeon Dae-Young , Jeong Park So , Mouis Mireille , Joo Min-Kyu , Barraud Sylvain , Kim Gyu-Tae , Ghibaudo Gérard
Published: July 2014

The error rate of low-field mobility (μ0) extracted from the conventional Y-function method in junctionless transistors (JLTs) is found to be linearly proportional to the channel doping concentration (Nd) for a typical value of the first order mobility attenuation factor θ0 ≈ 0.1 V−1. Therefore, for a better understanding of their physical operation with higher accuracy, a methodology for the extraction of the low-field mobility of the surface accumulation channel (μ0_acc) and the bulk neutral channel mobility (μbulk) of JLTs is proposed based on their unique operation principle. Interestingly, it is found that the different temperature dependence between μ0_acc and μbulk is also confirming that the distribution of point defects along the channel in the heavily doped Si channel of JLTs was non-uniform.
Triple plasmon resonance of bimetal nanoshell
Authors: Shirzaditabar Farzad , Saliminasab Maryam , Arghavani Nia Borhan
Published: July 2014

In this paper, light absorption spectra properties of a bimetal multilayer nanoshell based on quasi-static approach are investigated. Comparing with silver-dielectric-silver and silver-dielectric-gold nanoshells, gold-dielectric-silver nanoshells have three intense and separated plasmon peaks which are more suitable for multiplex biosensing. Calculations show that relatively small thickness of outer silver shell and large dielectric constant of middle dielectric layer of gold-dielectric-silver nanoshell are suitable to obtain the triple plasmon resonance.
Transport in ZnCoO thin films with stable bound magnetic polarons
Authors: Kaspar Tim , Fiedler Jan , Skorupa Ilona , Bürger Danilo , Schmidt Oliver G. , Schmidt Heidemarie
Published: July 2014

Diluted magnetic ZnCoO films with 5 at.% Co have been fabricated by pulsed laser deposition on c-plane sapphire substrates and Schottky and Ohmic contacts have been prepared in top-top configuration. The diode current is significantly reduced after the diode has been subjected to an external magnetic field. In the reverse bias range the corresponding positive magnetoresistance is persistent and amounts to more than 1800% (50 K), 240% (30 K), and 50% (5 K). This huge magnetoresistance can be attributed to the large internal magnetic field in depleted ZnCoO with ferromagnetic exchange between stable bound magnetic polarons.
Li4FeH6: Iron-containing complex hydride with high gravimetric hydrogen density
Authors: Saitoh Hiroyuki , Takagi Shigeyuki , Matsuo Motoaki , Iijima Yuki , Endo Naruki , Aoki Katsutoshi , Orimo Shin-ichi
Published: July 2014

Li4FeH6, which has the highest gravimetric hydrogen density of iron-containing complex hydrides reported so far, is synthesized by hydrogenation of a powder mixture of iron and LiH above 6.1 GPa at 900 °C. In situ synchrotron radiation X-ray diffraction measurements reveal that while kinetics require high temperature and thus high pressure for the synthesis, Li4FeH6 is expected to be thermodynamically stable slightly below room temperature at ambient pressure; further synthetic studies to suppress the kinetic effects may enable us to synthesize Li4FeH6 at moderate pressures. Li4FeH6 can be recovered at ambient conditions where Li4FeH6 is metastable.
Effect of the band structure of InGaN/GaN quantum well on the surface plasmon enhanced light-emitting diodes
Authors: Li Yi , Zhang Rong , Liu Bin , Xie Zili , Zhang Guogang , Tao Tao , Zhuang Zhe , Zhi Ting , Zheng Youdou
Published: July 2014

The spontaneous emission (SE) of InGaN/GaN quantum well (QW) structure with silver(Ag) coated on the n-GaN layer has been investigated by using six-by-six K-P method taking into account the electron-hole band structures, the photon density of states of surface plasmon polariton (SPP), and the evanescent fields of SPP. The SE into SPP mode can be remarkably enhanced due to the increase of electron-hole pairs near the Ag by modulating the InGaN/GaN QW structure or increasing the carrier injection. However, the ratio between the total SE rates into SPP mode and free space will approach to saturation or slightly decrease for the optimized structures with various distances between Ag film and QW layer at a high injection carrier density. Furthermore, the Ga-face QW structure has a higher SE rate than the N-face QW structure due to the overlap region of electron-hole pairs nearer to the Ag film.
Conductance control at the LaAlO3/SrTiO3-interface by a multiferroic BiFeO3 ad-layer
Authors: Mix Christian , Finizio Simone , Kläui Mathias , Jakob Gerhard
Published: July 2014

Multilayered BiFeO3 (BFO)/LaAlO3 (LAO) thin film samples were fabricated on SrTiO3 (STO) substrates by pulsed laser deposition. In this work, the ferroelectric polarization of a multiferroic BFO ad-layer on top of the quasi-two-dimensional electron gas (2DEG) at the LAO/STO interface is used to manipulate the conductivity of the quasi-2DEG. By microstructuring the conductive area of the LAO/STO-interface, a four-point geometry for the measurement of the resistivity was achieved. Piezo force microscopy allows for imaging and poling the spontaneous ferroelectric polarization of the multiferroic layer. The resistance changes showed a linear dependence on the area scanned and a hysteretic behavior with respect to the voltages applied in the scanning process. This is evidence for the ferroelectric polarization of the multiferroic causing the resistance changes. Coupling the antiferromagnetic BFO layer to another ferromagnetic layer could enable a magnetic field control of the conductance of the quasi-2DEG at the LAO/STO interface.
Bipolar gating of epitaxial graphene by intercalation of Ge
Authors: Baringhaus J. , Stöhr A. , Forti S. , Krasnikov S. A. , Zakharov A. A. , Starke U. , Tegenkamp C.
Published: July 2014

In this study, the ambivalent behavior of Ge intercalation is studied by means of scanning tunneling microscopy and spectroscopy as well as local 4-point probe transport measurements. In quantitative agreement with angle-resolved photoemission experiments, both p- and n-type doped graphene areas and their doping level were identified by local spectroscopy. The p-doped areas appear higher by 2 Å with respect to the n-doped areas suggesting incorporation of thicker Ge-layers accompanied by a modified coupling to the initial SiC-surface. Furthermore, the sheet resistance was measured on each of the patches separately. The intrinsic imbalance between the carrier types in the different areas is well reflected by the transport study. The process of intercalation does not affect the transport properties in comparison to pristine graphene pointing to a sufficient homogeneity of the decoupled graphene layer. Transport measurements across chemically gated pn-junctions reveal increased resistances, possibly due to enlarged tunneling barriers.
Probability of self-healing in damaged graphene bombarded by fullerene
Authors: Xu Zhi-Cheng , Zhong Wei-Rong
Published: July 2014

Using non-equilibrium molecular dynamics method, we study the self-healing behavior of graphene after bombarded by fullerene (C60) through controlling the environmental temperature and the incident velocity of C60. The self-healing probability depends on the size of graphene, the velocity of fullerene (C60), and the temperature of heat baths. It is suggested that the self-healing in damaged graphene originates from thermal fluctuation. Our results can offer additional insights for further understanding self-healing mechanisms and bombardment phenomena in low dimensional materials. Additionally, controlling the bombardment between the graphene and the fullerene (C60) may also lead to some potential applications in the surface cleaning of graphene and the production of nanopore.
Current-driven detection of terahertz radiation using a dual-grating-gate plasmonic detector
Authors: Boubanga-Tombet S. , Tanimoto Y. , Satou A. , Suemitsu T. , Wang Y. , Minamide H. , Ito H. , Fateev D. V. , Popov V. V. , Otsuji T.
Published: July 2014

We report on the detection of terahertz radiation by an on-chip planar asymmetric plasmonic structure in the frequency region above one terahertz. The detector is based on a field-effect transistor that has a dual grating gate structure with an asymmetric unit cell, which provides a geometrical asymmetry within the structure. Biasing the detector with a dc source-to-drain current in the linear region of the current-voltage characteristic introduces an additional asymmetry (electrical asymmetry) that enhances the detector responsivity by more than one order of magnitude (by a factor of 20) as compared with the unbiased case due to the cooperative effect of the geometrical and electrical asymmetries. In addition to the responsivity enhancement, we report a relatively low noise equivalent power and a peculiar non-monotonic dependence of the responsivity on the frequency, which results from the multi-plasmonic-cavity structure of the device.
Direct evidence of delayed electroluminescence from carbon nanotubes on the macroscale
Authors: Janas D. , Czechowski N. , Mackowski S. , Koziol K. K.
Published: July 2014

Spectrally resolved and kinetic response of electroluminescence was monitored from resistively heated carbon nanotube (CNT) macroassemblies. Sensitive detection system and custom-made setup for high-speed optoelectronic measurements were employed to investigate unsorted and single chirality-enriched CNTs. By increasing the content of (7,6) or (6,5) CNTs in a sample, the E11 emission peak in the infrared region became more narrow (∼150 nm), hence approaching that of commercial emitters for this spectral range. Moreover, electroluminescence initiation in CNTs occurred very rapidly and reached its full intensity within tens of milliseconds. Interestingly, observed delay between bias voltage application and electroluminescence proved triplet-triplet annihilation in the macroscopic assembly of CNTs.
Correlation between upconversion photoluminescence and dielectric response in Ba-substituted (Sr1−xBax)4(La0.85Ho0.025Yb0.125)2Ti4Nb6O30
Authors: Wei T. , Wang X. D. , Zhao C. Z. , Liu M. F. , Liu J. M.
Published: July 2014

The filled tetragonal tungsten bronze (Sr1−xBax)4(La0.85Ho0.025Yb0.125)2Ti4Nb6O30 (SBLTNx: Ho-Yb) ceramics with different Ba substitution levels (x) are prepared. The upconversion photoluminescence (UC-PL) and dielectric permittivity are investigated. The substitution of Sr2+ ions at the A2-sites by larger Ba2+ ions results in substantial variation of the UC-PL intensity as a function of substitution level x. Furthermore, the dielectric response to the substitution of Sr2+ by Ba2+ suggests a close correlation between the UC-PL intensity and dielectric permittivity. The origin for this correlation is discussed based on the random stress field (RSF) model.
Molecular phylogenetics of the Onobrychis genus (Fabaceae: Papilionoideae) using ITS and trnL–trnF DNA sequence data
Authors: Safaei Chaei Kar S. , Ghanavati F. , Naghavi M. R. , Amirabadi-zade H. , Rabiee R.
Published: July 2014

Onobrychis, comprising more than 130 species, is a genus of the family Fabaceae. At this time, the interspecies relationship of this biologically important genus is still a subject of great discussion and debate. To help resolve this disagreement, we used molecular phylogeny to analyse internal transcribed spacer (ITS) and trnL–trnF sequences of 76 species of Onobrychis. Bayesian interference, maximum parsimony and maximum likelihood analyses of nuclear ITS and plastid trnL–trnF DNA sequence data generated trees with strong posterior probability for two groups: Onobrychis subgen. Sisyrosema (including: Heliobrychis, Hymenobrychis, Afghanicae and Anthyllium sections) along with Laxiflorae section in Group I and Onobrychis subgen. Onobrychis (except Laxiflorae section) in the other (Group II). The Laxiflorae section roots back to the ancestral node for Sisyrosema subgen. O. viciifolia (cultivated species), which is closely associated with O. cyri var. cyri, suggesting that the latter may be a wild progenitor of O. viciifolia. The present study supported the paraphyly of subgenera Onobrychis and Sisyrosema. The study proposed the paraphyletic nature of the sections Onobrychis, Dendrobrychis, Heliobrychis and Hymenobrychis. Together with our molecular phylogenetic analyses we present a review of Onobrychis morphology and discuss and compare our results with those of earlier morphological and molecular phylogenetic analyses.
Teaching argumentation theory to doctors
Authors: Rubinelli Sara , Zanini Claudia
Published: July 2014

This paper supports the need for health professionals to be trained in argumentation theory, by illustrating the challenges that they face in interacting with patients and according to the different models of consultation that patients prefer. While there is no ideal model of consultation that can be promoted universally, the ability to construct arguments in support of health professionals’ points of view, as well as the ability to engage in critical discussion with patients, translate in essential skills for reaching patients’ agreement when communication develops through the interpretative model or the informed decision model or, eventually, shared-decision making.
The Council of Europe’s Language Education Policy Profile
Authors: Little David
Published: July 2014

This article begins by summarizing the history of the Council of Europe’s language education policy and goes on to explain the process by which its Language Policy Unit develops Language Education Policy Profiles for member states and for regions and cities in member states. It then draws on the author’s involvement in the Language Education Policy Profiles undertaken for Austria and the city of Sheffield to illustrate the contribution that the process can make to the exploitation and management of diversity in language education policy and practice. It concludes by briefly considering some of the limitations of the Language Education Policy Profile, the aspirations of the Council of Europe’s Languages in/for Education project, and the challenge of converting the ideal of plurilingual and intercultural education into lived reality.
Proverbial homogeneity: A cross-linguistic examination of Korean and Indonesian
Authors: Lee Sang-Oak
Published: July 2014

This study explores the use of keywords in proverbs in Korean, English, Chinese, and Indonesian. The study applies the traditional corpus linguistic tools of frequency and ranking to the keywords found in proverbs in an attempt to characterize the proverbs of these languages. The frequency data show that English proverbs are dominated by abstract keywords like “love, God, age, foolishness, wisdom, poverty, good, evil, and truth.” On the other hand, Chinese proverbs are dominated by more “action oriented” and “pragmatic concern” keywords such as “heart, time, talk/say, act/do, words, method, and knowledge,” showing a clear divergence from the frequency structure of English proverb keywords. Surprisingly, Korean proverb keywords, just like the English keywords, are also found to share very little in common with Chinese, a longstanding neighbor which has strongly influenced the cultural life of Korea over the last two millennia. Instead, the data show that the proverb keyword structure most resembles that of Indonesian, both having material/physical terms dominating the keywords and both sharing three common top-ranking keywords: water, dog, and cow.
Verb sequences and early verb inflection in Spanish
Authors: Rojas Nieto Cecilia
Published: July 2014

Usage-based studies of morphological development have provided robust evidence of the relevance of local root/inflection combinations for children’s detection of morphological patterns. This paper shows that dialogical continuity is supported by interlocutors’ use of the same lexical verb, presenting children with neighboring morphological forms of the verb, thereby providing an additional source of information on inflectional contrasts. The most prominent neighboring patterns of verb morphology found in Mexican Spanish interactions involve person inflection; first and second person forms reveal sequential complementarity while third person forms employ the continuous use of same form by interlocutors. These conversational sequences constitute the context in which children apply their pattern-finding abilities. Children may participate and work on this aspect from the age of two onwards.
Chapter 7. Collaborative tasks for negotiation of intercultural meaning in virtual worlds and video-web communication
Authors: Canto Silvia , de Graaff Rick , Jauregi Kristi
Published: July 2014

In many foreign language education settings, communication tasks in the target language mostly take place between nonnative-speaker classmates sharing the same mother tongue. ‘Networked’ environments such as voice-enabled 3D virtual worlds or video-web communication may have an added value in creating opportunities for language learners to synchronously communicate outside the classroom. As such, these tools may facilitate intercultural communication and collaboration with other (native) speakers of the target language. In the European Networked Interaction in Foreign Language Acquisition and Research (NIFLAR) project,* innovative e-learning environments were designed and studied for their potential to create authentic and interactive contexts that support the development of intercultural competence in foreign language learning contexts. The technology-mediated pedagogical tasks targeted intercultural communicative competence (following, e.g. Byram 1997; and Müller-Jacquier 2003), in which intercultural awareness and social interaction seek to play a much larger role than it is possible in current classroom-based foreign language education. The NIFLAR design also took into consideration the set of design principles that have emerged from TBLT research (Ellis 2003; Doughty & Long 2003; Long 2009; Norris 2009; Van den Branden 2006; Willis 1996). In this chapter we present NIFLAR’s technology-mediated, task-based framework for the development of intercultural competence and discuss its application to both video-web task-based communication and the virtual world Second Life by Dutch learners of Spanish communicating with native-speaker teachers of Spanish. We offer qualitative and quantitative data gleaned from the completion of two tasks and discuss the potential effects of technology-mediated TBLT in such environments, focusing on negotiation of intercultural meaning in communication between language learners and native speakers.
The impact of cultural background knowledge in the processing of metaphorical expressions
Authors: Zheng Binghan , Xiang Xia
Published: July 2014

This study aims to explore the role and possible impact of cultural background knowledge (CBK) on performance in sight translation, specifically the translation of metaphorical expressions (MEs). A between-subjects experiment was designed for 68 interpreting students who were assigned to a control group (CG) and an experimental group (EG). They were asked to sight translate a speech containing ten MEs, with only the EG members given relevant CBK beforehand. The study triangulates data from the recordings of sight translation outputs, the transcriptions of the recordings, and the subjects’ guided interviews. The paper concludes with two main findings: (1) CBK markedly alleviates the cognitive load imposed by MEs and thus facilitates the process of translation by shortening the processing time and improving the translation quality; (2) although CBK does not exert a significant influence on the choice of translation strategies as a whole, it discernibly reduces the use of omission as a coping strategy to deal with inadequacies in the understanding of metaphorical meanings.
Rac1 and Aurora A regulate MCAK to polarize microtubule growth in migrating endothelial cells
Authors: Braun Alexander , Dang Kyvan , Buslig Felinah , Baird Michelle A. , Davidson Michael W. , Waterman Clare M. , Myers Kenneth A.
Published: July 2014

Endothelial cells (ECs) migrate directionally during angiogenesis and wound healing by polarizing to extracellular cues to guide directional movement. EC polarization is controlled by microtubule (MT) growth dynamics, which are regulated by MT-associated proteins (MAPs) that alter MT stability. Mitotic centromere-associated kinesin (MCAK) is a MAP that promotes MT disassembly within the mitotic spindle, yet its function in regulating MT dynamics to promote EC polarity and migration has not been investigated. We used high-resolution fluorescence microscopy coupled with computational image analysis to elucidate the role of MCAK in regulating MT growth dynamics, morphology, and directional migration of ECs. Our results show that MCAK-mediated depolymerization of MTs is specifically targeted to the trailing edge of polarized wound-edge ECs. Regulation of MCAK function is dependent on Aurora A kinase, which is regionally enhanced by signaling from the small guanosine triphosphatase, Rac1. Thus, a Rac1–Aurora A–MCAK signaling pathway mediates EC polarization and directional migration by promoting regional differences in MT dynamics in the leading and trailing cell edges.
Bud3 activates Cdc42 to establish a proper growth site in budding yeast
Authors: Kang Pil Jung , Lee Mid Eum , Park Hay-Oak
Published: July 2014

Cell polarization occurs along a single axis that is generally determined by a spatial cue, yet the underlying mechanism is poorly understood. Using biochemical assays and live-cell imaging, we show that cell polarization to a proper growth site requires activation of Cdc42 by Bud3 in haploid budding yeast. Bud3 catalyzes the release of guanosine diphosphate (GDP) from Cdc42 and elevates intracellular Cdc42–guanosine triphosphate (GTP) levels in cells with inactive Cdc24, which has as of yet been the sole GDP–GTP exchange factor for Cdc42. Cdc42 is activated in two temporal steps in the G1 phase: the first depends on Bud3, whereas subsequent activation depends on Cdc24. Mutational analyses suggest that biphasic activation of Cdc42 in G1 is necessary for assembly of a proper bud site. Biphasic activation of Cdc42 or Rac GTPases may be a general mechanism for spatial cue–directed cell polarization in eukaryotes.
In vivo collective cell migration requires an LPAR2-dependent increase in tissue fluidity
Authors: Kuriyama Sei , Theveneau Eric , Benedetto Alexandre , Parsons Maddy , Tanaka Masamitsu , Charras Guillaume , Kabla Alexandre , Mayor Roberto
Published: July 2014

Collective cell migration (CCM) and epithelial–mesenchymal transition (EMT) are common to cancer and morphogenesis, and are often considered to be mutually exclusive in spite of the fact that many cancer and embryonic cells that have gone through EMT still cooperate to migrate collectively. Here we use neural crest (NC) cells to address the question of how cells that have down-regulated cell–cell adhesions can migrate collectively. NC cell dissociation relies on a qualitative and quantitative change of the cadherin repertoire. We found that the level of cell–cell adhesion is precisely regulated by internalization of N-cadherin downstream of lysophosphatidic acid (LPA) receptor 2. Rather than promoting the generation of single, fully mesenchymal cells, this reduction of membrane N-cadherin only triggers a partial mesenchymal phenotype. This intermediate phenotype is characterized by an increase in tissue fluidity akin to a solid-like–to–fluid-like transition. This change of plasticity allows cells to migrate under physical constraints without abolishing cell cooperation required for collectiveness.
Phosphatidic acid phospholipase A1 mediates ER–Golgi transit of a family of G protein–coupled receptors
Authors: Kunduri Govind , Yuan Changqing , Parthibane Velayoudame , Nyswaner Katherine M. , Kanwar Ritu , Nagashima Kunio , Britt Steven G. , Mehta Nickita , Kotu Varshika , Porterfield Mindy , Tiemeyer Michael , Dolph Patrick J. , Acharya Usha , Acharya Jairaj K.
Published: July 2014

The coat protein II (COPII)–coated vesicular system transports newly synthesized secretory and membrane proteins from the endoplasmic reticulum (ER) to the Golgi complex. Recruitment of cargo into COPII vesicles requires an interaction of COPII proteins either with the cargo molecules directly or with cargo receptors for anterograde trafficking. We show that cytosolic phosphatidic acid phospholipase A1 (PAPLA1) interacts with COPII protein family members and is required for the transport of Rh1 (rhodopsin 1), an N-glycosylated G protein–coupled receptor (GPCR), from the ER to the Golgi complex. In papla1 mutants, in the absence of transport to the Golgi, Rh1 is aberrantly glycosylated and is mislocalized. These defects lead to decreased levels of the protein and decreased sensitivity of the photoreceptors to light. Several GPCRs, including other rhodopsins and Bride of sevenless, are similarly affected. Our findings show that a cytosolic protein is necessary for transit of selective transmembrane receptor cargo by the COPII coat for anterograde trafficking.
First Report of Tomato yellow leaf curl virus Infecting Eustoma (Eustoma grandiflorum) in Korea
Authors: Kil E.-J. , Byun H.-S. , Kim S. , Hwang H. , Kim M.-K. , Kim C.-S. , Choi H.-S. , Lee K.-Y. , Lee S.
Published: July 2014

Eustoma (Eustoma grandiflorum), also called lisianthus, belongs to the family Gentianaceae and is cultivated for flower production globally (1), including in Korea. At least 10 viruses can infect eustoma, including Cucumber mosaic virus (genus Cucumovirus), Tobacco mosaic virus (genus Tobamovirus), Tomato spotted wilt virus (genus Tospovirus), and Tomato yellow leaf curl virus (TYLCV, genus Begomovirus) (1,2). In December 2012, disease symptoms such as leaf curling and stunting were observed on eustoma plants grown in Gumi, Korea, where TYLCV outbreak was reported on tomato farms. In a eustoma greenhouse, about 5% of eustoma plants showed the leaf curling and stunting symptoms. Total DNA was isolated from 15 symptomatic eustoma plants with a Viral Gene-spin Viral DNA/RNA Extraction Kit (iNtRON Biotechnology, Seongnam, Korea) and viral DNA was amplified by rolling circle amplification (TempliPhi Amplification Kit, GE Healthcare Life Sciences, Uppsala, Sweden) following the manufacturer's instructions. All amplicons were digested with the restriction enzyme SacI (TaKaRa Bio, Shiga, Japan) and 2.8-kb DNA fragments were verified on an agarose gel. Fifteen digested DNA fragments were purified from the gel, ligated into pGEM-T easy vector (Promega, Madison, WI), and sequenced (Macrogen, Seoul, Korea, GenBank Accession No. KF225312.1). A BLAST search exhibited a 99% identity to TYLCV previously reported in Korea (GenBank HM856911.1). This is the first report of TYLCV in eustoma plants in Korea. To identify the movement and replication of TYLCV in infected eustoma plants, PCR and Southern hybridization analysis were performed with samples from four organs (flower, leaf, stem, and root) of three individual TYLCV-infected plants. TYLCV TYL DNA from each organ sample was amplified using 2× Taq PCR MasterMix (Bioneer, Daejeon, Korea) with TYLCV-specific primers (TYLCV-F: 5′-ATATTACCGGATGGCCGCGCCT-3′, CV-R: 5′-TCCACGGGGAACATCAGGGCTT-3′). Single-stranded as well as double-stranded TYLCV DNA were identified from all organs of symptomatic eustoma, indicating TYLCV can replicate and move systemically in eustoma plants. Whitefly (Bemisia tabaci)-mediated plant-to-plant viral transmission was performed with one TYLCV-infected eustoma plant and five healthy eustoma plants and revealed that 80% (4 of 5) of the eustoma plants were infected by whitefly-mediated transmission. These results indicate that TYLCV-infected eustoma plants could act as virus reservoirs to healthy eustoma plants as well as other potential TYLCV hosts, such as tomatoes. In Korea, TYLCV has been the most notorious plant virus since 2008 (3), but, until now, TYLCV infection in eustoma plants has not been reported in Korea.

References: (1) C. C. Chen et al. Plant Dis. 84:506, 2000. (2) A. Kritzman et al. Plant Dis. 84:1185, 2000. (3) H. Lee et al. Mol. Cells 30:467, 2010.
First Report of Tomato mosaic virus on Common Sow Thistle in Iran
Authors: Hashemi S. S. , Rakhshandehroo F. , Shahraeen N.
Published: July 2014

The natural incidence of Tomato mosaic virus (ToMV) in common sow thistle (Sonchus oleraceus) from vegetable fields was assessed to determine the role of this weed species as a virus inoculum source. Twenty sow thistle plants with virus-like foliar symptoms including mosaic and malformations were collected from five vegetable fields in Tehran province, Iran, and analyzed by double antibody sandwich (DAS)-ELISA for the presence of ToMV, Tobacco mosaic virus (TMV), and Cucumber mosaic virus (CMV) using specific polyclonal antibodies (Agdia, Elkhart, IN). Six out of the 20 sow thistle plants tested by ELISA were infected with ToMV. This virus was detected in three of five vegetable fields surveyed, while CMV and TMV were not detected. Mosaic symptoms were associated with the ToMV infection, similar to those caused by TMV in common sow thistle in Iran (2). Viral infection was confirmed by RT-PCR using previously described specific primers to amplify a region in the coat protein gene of ToMV (3). The RT-PCR resulted in the amplification of an expected fragment of ~480 bp from ToMV-infected but not from healthy plants. The nucleotide sequence of the amplified DNA fragment was purified (GeneJET Gel Extraction Kit, Fermentas, Germany), directly sequenced, and deposited in GenBank as Accession No. KF527464. BLAST analysis showed 95 to 97% and 98 to 100% identity at the nucleotide and amino acid levels, respectively, with comparable sequences of other ToMV isolates (GenBank AF062519, FN985165, GQ280794, and JX857634). Mechanical inoculation of sow thistle plants with sap of symptomatic sow thistles reproduced symptoms of field-infected sow thistles. The presence of ToMV in the inoculated plants was confirmed by ELISA and RT-PCR. This suggested that ToMV could be the causal agent of the disease on sow thistle. In our earlier studies, the distribution and genetic diversity of ToMV isolates infecting vegetable crops and weed plants were studied (1); however, to our knowledge, this is the first report of ToMV infecting common sow thistle in Iran.

References: (1) V. Aghamohammadi et al. J. Plant Pathol. 95:339, 2013. (2) A. Alishiri et al. Plant Pathol. J. 29:260, 2013. (3) B. Letschert et al. J. Virol. Methods 106:10, 2002.
Chronic impairment of bumblebee natural foraging behaviour induced by sublethal pesticide exposure
Authors: Gill Richard J. , Raine Nigel E.
Published: July 2014

Insect pollination is a vital ecosystem service that maintains biodiversity and sustains agricultural crop yields. Social bees are essential insect pollinators, so it is concerning that their populations are in global decline.

Although pesticide exposure has been implicated as a possible cause for bee declines, we currently have a limited understanding of the risk these chemicals pose. Whilst environmental exposure to pesticides typically has non‐lethal effects on individual bees, recent reports suggest that sublethal exposure can affect important behavioural traits such as foraging. However, at present, we know comparatively little about how natural foraging behaviour is impaired and the relative impacts of acute and chronic effects.

Using Radio‐Frequency Identification (RFID) tagging technology, we examined how the day‐to‐day foraging patterns of bumblebees (Bombus terrestris) were affected when exposed to either a neonicotinoid (imidacloprid) and/or a pyrethroid (λ‐cyhalothrin) independently and in combination over a four‐week period. This is the first study to provide data on the impacts of combined and individual pesticide exposure on the temporal dynamics of foraging behaviour in the field over a prolonged period of time.

Our results show that neonicotinoid exposure has both acute and chronic effects on overall foraging activity. Whilst foragers from control colonies improved their pollen foraging performance as they gained experience, the performance of bees exposed to imidacloprid became worse: chronic behavioural impairment. We also found evidence, suggesting that pesticide exposure can change forager preferences for the flower types from which they collect pollen.

Our findings highlight the importance of considering prolonged exposure (which happens in the field) when assessing the risk that pesticides pose to bees. The effects of chronic pesticide exposure could have serious detrimental consequences for both colony survival and also the pollination services provided by these essential insect pollinators.
Impacts of breeder loss on social structure, reproduction and population growth in a social canid
Authors: Borg Bridget L. , Brainerd Scott M. , Meier Thomas J. , Prugh Laura R.
Published: July 2014

The importance of individuals to the dynamics of populations may depend on reproductive status, especially for species with complex social structure. Loss of reproductive individuals in socially complex species could disproportionately affect population dynamics by destabilizing social structure and reducing population growth. Alternatively, compensatory mechanisms such as rapid replacement of breeders may result in little disruption. The impact of breeder loss on the population dynamics of social species remains poorly understood.

We evaluated the effect of breeder loss on social stability, recruitment and population growth of grey wolves (Canis lupus) in Denali National Park and Preserve, Alaska using a 26‐year dataset of 387 radiocollared wolves. Harvest of breeding wolves is a highly contentious conservation and management issue worldwide, with unknown population‐level consequences.

Breeder loss preceded 77% of cases (n = 53) of pack dissolution from 1986 to 2012. Packs were more likely to dissolve if a female or both breeders were lost and pack size was small. Harvest of breeders increased the probability of pack dissolution, likely because the timing of harvest coincided with the breeding season of wolves. Rates of denning and successful recruitment were uniformly high for packs that did not experience breeder loss; however, packs that lost breeders exhibited lower denning and recruitment rates. Breeder mortality and pack dissolution had no significant effects on immediate or longer term population dynamics.

Our results indicate the importance of breeding individuals is context dependent. The impact of breeder loss on social group persistence, reproduction and population growth may be greatest when average group sizes are small and mortality occurs during the breeding season. This study highlights the importance of reproductive individuals in maintaining group cohesion in social species, but at the population level socially complex species may be resilient to disruption and harvest through strong compensatory mechanisms.
Scanning Electron Microscope Analysis of Gunshot Defects to Bone: An Underutilized Source of Information on Ballistic Trauma
Authors: Rickman John M. , Smith Martin J.
Published: July 2014

Recent years have seen increasing involvement by forensic anthropologists in the interpretation of skeletal trauma. With regard to ballistic injuries, there is now a large literature detailing gross features of such trauma; however, less attention has been given to microscopic characteristics. This article presents analysis of experimentally induced gunshot trauma in animal bone (Bos taurusscapulae) using full metal jacket (FMJ), soft point (SP), and captive bolt projectiles. The results were examined using scanning electron microscopy (SEM). Additional analysis was conducted on a purported parietal gunshot lesion in a human cranial specimen. A range of features was observed in these samples suggesting that fibrolamellar bone response to projectile impact is analogous to that observed in synthetic composite laminates. The results indicate that direction of bullet travel can be discerned microscopically even when it is ambiguous on gross examination. It was also possible to distinguishSPfromFMJlesions.SEManalysis is therefore recommended as a previously underexploited tool in the analysis of ballistic trauma.
Diabetes self‐management support for patients with low health literacy: Perceptions of patients and providers针对低健康素养患者的糖尿病自我管理支持：患者与提供者的观念
Authors: Fransen Mirjam P. , Beune Erik J.A.J. , Baim‐Lance Abigail M. , Bruessing Raynold C. , Essink‐Bot Marie‐Louise
Published: July 2014

Background

The aim of the present study was to explore perceptions and strategies of health care providers regarding diabetes self‐management support for patients with low health literacy (LHL), and to compare their self‐management support with the needs of patients with LHL and type 2 diabetes. This study serves as a problem analysis for systematic intervention development to improve diabetes self‐management among patients with LHL.

Methods

This qualitative study used in‐depth interviews with general practitioners (n = 4), nurse practitioners (n = 5), and patients with LHL (n = 31). The results of the interviews with health care providers guided the patient interviews. In addition, we observed 10 general practice consultations.

Results

Providers described patients with LHL as uninvolved and less motivated patients who do not understand self‐management. Their main strategy to improve self‐management was to provide standard information on a repeated basis. Patients with LHL seemed to have a different view of diabetes self‐management than their providers. Most demonstrated a low awareness of what self‐management involves, but did not express needing more information. They reported several practical barriers to self‐management, although they seemed reluctant to use the information provided to overcome them.

Conclusions

Providing and repeating information does not fit the needs of patients with LHL regarding diabetes self‐management support. Health care providers do not seem to have the insight or the tools to systematically support diabetes self‐management in this group. Systematic intervention development with a focus on skills‐based approaches rather than cognition development may improve diabetes self‐management support of patients with LHL.