bluuebunny/crossref_metadata_2025 huggingface dataset:
Completing the structural family portrait of the human EphB tyrosine kinase domains
Authors: Overman Ross C. , Debreczeni Judit E. , Truman Caroline M. , McAlister Mark S. , Attwood Teresa K.
Published: February 2014

The EphB receptors have key roles in cell morphology, adhesion, migration and invasion, and their aberrant action has been linked with the development and progression of many different tumor types. Their conflicting expression patterns in cancer tissues, combined with their high sequence and structural identity, present interesting challenges to those seeking to develop selective therapeutic molecules targeting this large receptor family. Here, we present the first structure of the EphB1 tyrosine kinase domain determined by X‐ray crystallography to 2.5Å. Our comparative crystalisation analysis of the human EphB family kinases has also yielded new crystal forms of the human EphB2 and EphB4 catalytic domains. Unable to crystallize the wild‐type EphB3 kinase domain, we used rational engineering (based on our new structures of EphB1, EphB2, and EphB4) to identify a single point mutation which facilitated its crystallization and structure determination to 2.2 Å. This mutation also improved the soluble recombinant yield of this kinase within Escherichia coli, and increased both its intrinsic stability and catalytic turnover, without affecting its ligand‐binding profile. The partial ordering of the activation loop in the EphB3 structure alludes to a potential cis‐phosphorylation mechanism for the EphB kinases. With the kinase domain structures of all four catalytically competent human EphB receptors now determined, a picture begins to emerge of possible opportunities to produce EphB isozyme‐selective kinase inhibitors for mechanistic studies and therapeutic applications.
Heating of the Mn spin system by photoexcited holes in type‐II (Zn,Mn)Se/(Be,Mn)Te quantum wells
Authors: Debus J. , Maksimov A. A. , Dunker D. , Yakovlev D. R. , Filatov E. V. , Tartakovskii I. I. , Ivanov V. Yu. , Waag A. , Bayer M.
Published: February 2014

The efficiency of the Mn‐spin system heating under pulsed laser excitation is studied in diluted magnetic semiconductor heterostructures Zn0.99 Mn0.01 Se/Be0.93 Mn0.07 Te with type‐II band alignment by means of time‐resolved photoluminescence and pump‐probe reflectivity. An essential role in the heating is played by multiple spin‐flip scatterings of a hole with localized spins of Mn2+ ions. The efficiency of the spin and energy transfer from photoexcited holes to Mn ions of the Zn0.99 Mn0.01 Se layer considerably depends on the hole lifetime in this layer. This lifetime can be limited by the hole relaxation into the Be0.93 Mn0.07 Te layers and is strongly sensitive to the excitation power and Zn0.99 Mn0.01 Se layer thickness. These dependences allow us to determine a characteristic time of about 20ps for the spin and energy transfer from photoexcited holes to the Mn spin system.
An investigation into defect reduction techniques for growth of non‐polar GaN on sapphire
Authors: Sutherland Danny , Oehler Fabrice , Zhu Tongtong , Griffiths James T. , Badcock Thomas J. , Dawson Philip , Emery Robert M. , Kappers Menno J. , Humphreys Colin J. , Oliver Rachel A.
Published: February 2014

In this paper we describe the implementation and the characterisation of five different in‐situ defect reduction techniques for non‐polar (a ‐plane) GaN growth on r ‐plane sapphire. Sample 1 (3D/2D) employs a methodology frequently applied on the c ‐plane, involving a low temperature nucleation layer (LTNL) followed by 3D GaN island formation and lateral coalescence. For Sample 2 (d3D) GaN islands are grown directly onto the sapphire with no LTNL, followed by lateral growth. Sample 3 (d3D Si) follows a similar procedure, but with high silicon doping in order to adjust the 3D GaN island shape. Sample 4 (SiNx) utilises a silicon nitride interlayer between a LTNL and subsequent growth of a GaN layer. Sample 5 is grown by epitaxial lateral overgrowth (ELOG) coupled with a SiNx interlayer. X‐ray diffraction, scanning electron microscopy and cathodoluminescence are used to identify defects, and determined the threading defect density to vary from 1 x 1010–1 x 109 cm–2 and basal‐plane stacking fault (BSF) density to vary from 5 x 105 – 5 x 103 cm‐1. The improvement in crystal quality is reflected in the photoluminescence spectra by a comparison of the ratio of the GaN near band edge (NBE) emission to the BSF associated emission. It was determined that the ELOG method was most successful in blocking BSFs, with a density reduction of 2 orders of magnitude resulting in a fifteen‐fold increase in the NBE:BSF emission ratio increase. (© 2014 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Impact of potassium and water on the electronic properties of InN(0001) surfaces
Authors: Reiß S. , Eisenhardt A. , Krischok S. , Himmerlich M.
Published: February 2014

In this work we investigate the interaction of potassium and water with 2×2 reconstructed InN(0001) surfaces prepared by plasma‐assisted molecular beam epitaxy. The influence of adsorbate‐substrate‐interaction on surface properties is characterized in‐situ by photoelectron spectroscopy. Potassium exposure leads to a strong reduction in the work function Φ to 1.6 eV revealing a charge transfer from the adsorbate to the InN surface. In parallel, a reduction of the surface downward band bending by 0.2 eV and hence a reduced electron accumulation density is observed. While interaction of water with clean InN(0001)‐2×2 surfaces induces only minor changes in the surface band bending, water adsorption at potassium covered InN(0001) leads to a reversal of the K‐induced reduction in surface band bending and a slight increase of Φ to 2.4 eV. These results show that surrounding water modifies the interaction of potassium with InN(0001) surfaces. (© 2014 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
AgInS2–ZnS nanocrystals: Evidence of bistable states using light‐induced electron paramagnetic resonance and photoluminescence
Authors: Nobre Sónia S. , Renard Olivier , Lombard Christian , Chevallier Théo , Pépin‐Donat Brigitte , Le Blevennec Gilles
Published: February 2014

The precursor (AgIn)x Zn2(1–x)(S2CN(C2H5)2)4 was used to prepared AgInS2–ZnS nanocrystals with different compositions (x = 0.4 and x = 0.7) and with different time of reaction (10 min and 75 min). The photoluminescence features of the nanocrystals were addressed by combining steady‐state spectroscopy and light‐induced electron paramagnetic resonance. Both techniques showed the contribution of at least two components for the emission, previously assigned to surface and intrinsic states. Light‐induced electron paramagnetic resonance allowed detection of the photocreation both of irreversible paramagnetic species that are likely responsible for the nano‐crystals degradation assigned to surface states and of reversible paramagnetic species assigned to intrinsic states. Moreover, reversible bistable paramagnetic states were observed. This Letter provides a scheme that might be useful in addressing the well‐known problem of aging of the nanocrystals. (© 2014 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Hybrid silver nanoparticle and transparent conductive oxide structure for silicon solar cell applications
Authors: Huang Mei , Hameiri Ziv , Gong Hua , Wong Wah‐Chung , Aberle Armin Gerhard , Mueller Thomas
Published: February 2014

Transparent conductive oxides (TCOs) have been widely used as electrodes for various solar cell structures. For heterojunction silicon wafer solar cells, the front TCO layer not only serves as a top electrode (by enhancing the lateral conductance of the underlying amorphous silicon film), but also as an antireflection coating. These requirements make it difficult to simultaneously achieve excellent conductance and transparency, and thus, only high‐quality indium tin oxide (ITO) has as yet found its way into industrial heterojunction silicon wafer solar cells. In this Letter, we present a cost‐effective hybrid structure consisting of a TCO layer and a silver nano‐particle mesh. This structure enables the separate optimization of the electrical and optical requirements. The silver nanoparticle mesh provides high electrical conductance, while the TCO material is optimized as an antireflection coating. Therefore, this structure allows the use of cost‐effective (and less conductive) TCO materials, such as aluminium‐doped zinc oxide. The performance of the hybrid structure is demonstrated to achieve a similar visible transmission (∼86% in the 380–780 nm range) as an 80 nm thick ITO layer, but with 10 times better lateral conductance. The presented hybrid structure thus seems well suited for a variety of photovoltaic devices. (© 2014 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Determination of interface locations and layer thicknesses in SIMS and AES depth profiling of Si/Ti multilayer films by 50 at% definition
Authors: Hwang Hye Hyun , Jang Jong Shik , Kang Hee Jae , Kim Kyung Joong
Published: February 2014

Determination of the interface locations and the layer thicknesses in SIMS depth profiling of Si/Ti multilayer films was investigated by cesium ion beam. The raw SIMS depth profiles were converted to the compositional depth profiles by the relative sensitivity factors of Si and Ti derived from the atomic fractions of a reference Si‐Ti alloy film determined by Rutherford backscattering spectroscopy. The locations of the interfaces were determined by 50 at% definition in the compositional SIMS depth profiles, and the thicknesses of the Si and Ti layers were measured from the interfaces. The layer thicknesses of the Si/Ti multilayer film were also investigated by Auger electron spectroscopy depth profiling using the same process and same definition. Copyright © 2014 John Wiley & Sons, Ltd.
Enhancement of Light Output Power from LEDs Based on Monolayer Colloidal Crystal
Authors: Geng Chong , Wei Tongbo , Wang Xiaoqing , Shen Dezhong , Hao Zhibiao , Yan Qingfeng
Published: February 2014

One of the major challenges for the application of GaN‐based light emitting diodes (LEDs) in solid‐state lighting lies in the low light output power (LOP). Embedding nanostructures in LEDs has attracted considerable interest because they may improve the LOP of GaN‐based LEDs efficiently. Recent advances in nanostructures derived from monolayer colloidal crystal (MCC) have made remarkable progress in enhancing the performance of GaN‐based LEDs. In this review, the current state of the art in this field is highlighted with an emphasis on the fabrication of ordered nanostructures using large‐area, high‐quality MCCs and their demonstrated applications in enhancement of LOP from GaN‐based LEDs. We describe the remarkable achievements that have improved the internal quantum efficiency, the light extraction efficiency, or both from LEDs by taking advantages of diverse functions that the nanostructures provided. Finally, a perspective on the future development of enhancement of LOP by using the nanostructures derived from MCC is presented.
Mechanism change in a simulation of peer review: from junk support to elitism
Authors: Paolucci Mario , Grimaldo Francisco
Published: February 2014

Peer review works as the hinge of the scientific process, mediating between research and the awareness/acceptance of its results. While it might seem obvious that science would regulate itself scientifically, the consensus on peer review is eroding; a deeper understanding of its workings and potential alternatives is sorely needed. Employing a theoretical approach supported by agent-based simulation, we examined computational models of peer review, performing what we propose to call redesign, that is, the replication of simulations using different mechanisms. Here, we show that we are able to obtain the high sensitivity to rational cheating that is present in literature. In addition, we also show how this result appears to be fragile against small variations in mechanisms. Therefore, we argue that exploration of the parameter space is not enough if we want to support theoretical statements with simulation, and that exploration at the level of mechanisms is needed. These findings also support prudence in the application of simulation results based on single mechanisms, and endorse the use of complex agent platforms that encourage experimentation of diverse mechanisms.
Externalizing behavior and substance use related problems at 15 years in prenatally cocaine exposed adolescents
Authors: Min Meeyoung O. , Minnes Sonia , Lang Adelaide , Weishampel Paul , Short Elizabeth J. , Yoon Susan , Singer Lynn T.
Published: February 2014

The effect of prenatal cocaine exposure (PCE) on externalizing behavior and substance use related problems at 15 years of age was examined. Participants consisted of 358 adolescents (183 PCE, 175 non‐cocaine exposed (NCE)), primarily African–American and of low socioeconomic status, prospectively enrolled in a longitudinal study from birth. Regression analyses indicated that the amount of PCE was associated with higher externalizing behavioral problems (β = .15, p = .02). Adolescents with PCE were also 2.8 times (95% CI = 1.38–5.56) more likely to have substance use related problems than their NCE counterparts. No differences between PCE adolescents in non‐kinship adoptive/foster care (n = 44) and PCE adolescents in maternal/relative care (n = 139) were found in externalizing behavior or in the likelihood of substance use related problems. Findings demonstrate teratologic effects of PCE persisting into adolescence. PCE is a reliable marker for the potential development of problem behaviors in adolescence, including substance use related problems.
Preliminary development of the Adolescent Students' Basic Psychological Needs at School Scale
Authors: Tian Lili , Han Mengmeng , Huebner E. Scott
Published: February 2014

The aim of the present study was to develop and provide evidence for the validity of a new measure of adolescent students' psychological need satisfaction at school, using a sample of Chinese students. We conducted four studies with four independent samples (total n = 1872). The first study aimed to develop items for the new instrument and to ascertain its factorial structure using exploratory factor analysis procedures. The second study aimed to examine the instrument's factorial structure using confirmatory factor analysis procedures as well as to assess its internal consistency reliability, convergent and divergent validity. The third study aimed to assess its measurement invariance across gender and age. The fourth study aimed to test its test–retest reliability over time and predictive validity. These preliminary results showed that the new instrument has promising psychometric properties. The potential contributions of the new instrument for future research and educational practices were discussed.
EPA Guidance on Tobacco Dependence and Strategies for Smoking Cessation in People with Mental Illness
Authors: Rüther T. , Bobes J. , De Hert M. , Svensson T.H. , Mann K. , Batra A. , Gorwood P. , Möller H.J.
Published: February 2014

Tobacco dependence is the most common substance use disorder in adults with mental illness. The prevalence rates for tobacco dependence are two to four times higher in these patients than in the general population. Smoking has a strong, negative influence on the life expectancy and quality of life of mental health patients, and remains the leading preventable cause of death in this group. Despite these statistics, in some countries smokers with mental illness are disadvantaged in receiving intervention and support for their tobacco dependence, which is often overlooked or even tolerated. This statement from the European Psychiatric Association (EPA) systematically reviews the current evidence on tobacco dependence and withdrawal in patients with mental illness and their treatment. It provides seven recommendations for the core components of diagnostics and treatment in this patient group. These recommendations concern: (1) the recording process, (2) the timing of the intervention, (3) counselling specificities, (4) proposed treatments, (5) frequency of contact after stopping, (6) follow-up visits and (7) relapse prevention. They aim to help clinicians improve the care, health and well-being of patients suffering from mental illness.
Functional alterations in gut contractility after connexin36 ablation and evidence for gap junctions forming electrical synapses between nitrergic enteric neurons
Authors: Nagy James Imre , Urena-Ramirez Viridiana , Ghia Jean-Eric
Published: February 2014

Neurons in the enteric nervous system utilize numerous neurotransmitters to orchestrate rhythmic gut smooth muscle contractions. We examined whether electrical synapses formed by gap junctions containing connexin36 also contribute to communication between enteric neurons in mouse colon. Spontaneous contractility properties and responses to electrical field stimulation and cholinergic agonist were altered in gut from connexin36 knockout vs. wild‐type mice. Immunofluorescence revealed punctate labelling of connexin36 that was localized at appositions between somata of enteric neurons immunopositive for the enzyme nitric oxide synthase. There is indication for a possible functional role of gap junctions between inhibitory nitrergic enteric neurons.
Connexin hemichannel induced vascular leak suggests a new paradigm for cancer therapy
Authors: Zhang Jie , O'Carroll Simon J. , Henare Kimiora , Ching Lai-Ming , Ormonde Susan , Nicholson Louise F.B. , Danesh-Meyer Helen V. , Green Colin R.
Published: February 2014

It is 40 years since cancer growth was correlated with neovascularisation. Anti‐angiogenic drugs remain at the forefront of cancer investigations but progress has been disappointing and unexpected toxicities are emerging. Gap junction channels are implicated in lesion spread following injury, with channel blockers shown to improve healing; in particular preventing vascular disruption and/or restoring vascular integrity. Here we briefly review connexin roles in vascular leak and endothelial cell death that occurs following acute wounds and during chronic disease, and how connexin channel regulation has been used to ameliorate vascular disruption. We then review chronic inflammatory disorders and trauma in the eye, concluding that vascular disruption under these conditions mimics that seen in tumours, and can be prevented with connexin hemichannel modulation. We apply this knowledge to tumour vessel biology, proposing that contrary to current opinion, these data suggest a need to protect, maintain and/or restore cancer vasculature. This may lead to reduced tumour hypoxia, promote the survival of normal cells, and enable improved therapeutic delivery or more effective radiation therapy.
Differentiating connexin hemichannels and pannexin channels in cellular ATP release
Authors: Lohman Alexander W. , Isakson Brant E.
Published: February 2014

Adenosine triphosphate (ATP) plays a fundamental role in cellular communication, with its extracellular accumulation triggering purinergic signaling cascades in a diversity of cell types. While the roles for purinergic signaling in health and disease have been well established, identification and differentiation of the specific mechanisms controlling cellular ATP release is less well understood. Multiple mechanisms have been proposed to regulate ATP release with connexin (Cx) hemichannels and pannexin (Panx) channels receiving major focus. However, segregating the specific roles of Panxs and Cxs in ATP release in a plethora of physiological and pathological contexts has remained enigmatic. This multifaceted problem has arisen from the selectivity of pharmacological inhibitors for Panxs and Cxs, methodological differences in assessing Panx and Cx function and the potential compensation by other isoforms in gene silencing and genetic knockout models. Consequently, there remains a void in the current understanding of specific contributions of Panxs and Cxs in releasing ATP during homeostasis and disease. Differentiating the distinct signaling pathways that regulate these two channels will advance our current knowledge of cellular communication and aid in the development of novel rationally‐designed drugs for modulation of Panx and Cx activity, respectively.
The Angiomotins – From discovery to function
Authors: Moleirinho Susana , Guerrant William , Kissil Joseph L.
Published: February 2014

Angiomotins were originally identified as angiostatin binding proteins and implicated in the regulation of endothelial cell migration. Recent studies have shed light on the role of Angiomotins and other members of the Motin protein family in epithelial cells and in pathways directly linked to the pathogenesis of cancer. In particular, Motins have been shown to play a role in signaling pathways regulated by small G‐proteins and the Hippo–YAP pathway. In this review the role of the Motin protein family in these signaling pathways will be described and open questions will be discussed.
PML tumour suppression and beyond: Therapeutic implications
Authors: Gamell Cristina , Jan Paul Piotr , Haupt Ygal , Haupt Sue
Published: February 2014

Recognition of the tumour suppressive capacity of the Promyelocytic Leukemia protein (PML) has emerged beyond its identification through APL, to a broad spectrum of tumors. This ability has chiefly been linked to its role as a core component of dynamic structures termed PML Nuclear Bodies (PML‐NBs). In response to a variety of stresses, key factors and their molecular modifiers are recruited to PML‐NBs, where activating modifications are facilitated, leading to a cellular stress response. PML was also found to perform anti‐tumourigenic functions through cytoplasmic activities. Surprisingly, important recent research defined growth promoting capabilities of PML, which significantly challenges the notion of a ‘classic’ tumour suppressor. Through metabolic reprogramming, PML can afford a selective advantage for tumor cells in certain settings. The multiple forms in which PML exists are the likely explanation of this functional diversity. This behavioral ambiguity however raises a significant challenge to the design of strategies to therapeutically target PML. In this review we discuss this change of paradigm in the PML field and its ramifications, particularly for tailoring cancer therapies.
Arrhythmogenic cardiomyopathy and Brugada syndrome: Diseases of the connexome
Authors: Agullo-Pascual Esperanza , Cerrone Marina , Delmar Mario
Published: February 2014

This review summarizes data in support of the notion that the cardiac intercalated disc is the host of a protein interacting network, called “the connexome”, where molecules classically defined as belonging to one particular structure (e.g., desmosomes, gap junctions, sodium channel complex) actually interact with others, and together, control excitability, electrical coupling and intercellular adhesion in the heart. The concept of the connexome is then translated into the understanding of the mechanisms leading to two inherited arrhythmia diseases: arrhythmogenic cardiomyopathy, and Brugada syndrome. The cross‐over points in these two diseases are addressed to then suggest that, though separate identifiable clinical entities, they represent “bookends” of a spectrum of manifestations that vary depending on the effect that a particular mutation has on the connexome as a whole.
Sensitivities of the equilibrium line altitude to temperature and precipitation changes along the Andes
Authors: Sagredo Esteban A. , Rupper Summer , Lowell Thomas V.
Published: February 2014

Equilibrium line altitudes (ELAs) of alpine glaciers are sensitive indicators of climate change and have been commonly used to reconstruct paleoclimates at different temporal and spatial scales. However, accurate interpretations of ELA fluctuations rely on a quantitative understanding of the sensitivity of ELAs to changes in climate. We applied a full surface energy- and mass-balance model to quantify ELA sensitivity to temperature and precipitation changes across the range of climate conditions found in the Andes. Model results show that ELA response has a strong spatial variability across the glaciated regions of South America. This spatial variability correlates with the distribution of the present-day mean climate conditions observed along the Andes. We find that ELAs respond linearly to changes in temperature, with the magnitude of the response being prescribed by the local lapse rates. ELA sensitivities to precipitation changes are nearly linear and are inversely correlated with the emissivity of the atmosphere. Temperature sensitivities are greatest in the inner tropics; precipitation becomes more important in the subtropics and northernmost mid-latitudes. These results can be considered an important step towards developing a framework for understanding past episodes of glacial fluctuations and ultimately for predicting glacier response to future climate changes.
Flow of a falling liquid curtain into a pool
Authors: Kyotoh Harumichi , Fujita Kazuki , Nakano Koichi , Tsuda Takeaki
Published: February 2014

We investigate the low-Weber-number flow of a liquid curtain bridged between two vertical edge guides and a pool surface. Three flow patterns, namely, steady vertical flow, steady oblique flow, and oscillatory oblique flow, are observed in our experiment. These patterns are caused by the Coanda effect of the jet around the meniscus that is formed in the matching region common to the liquid curtain and the pool surface. Here, the deflection angle of the jet is greater than $90^\circ $. The equation describing the motion of the liquid curtain applicable for a finite curtain slope is obtained using the intrinsic coordinate system in which the distance along the curtain is selected as one of the coordinates, and the equation of the meniscus motion is derived by considering the conservation of momentum. The curtain deformations of oblique flows are analysed by generating numerical simulations of these equations, and the simulation results are then compared with experimental results. Also, the period of oscillatory oblique flow is discussed and explained via the response analyses of the curtain, and the result shows that the period of the oscillations is close to that of the most amplified mode of the liquid curtain. Further, the detachment angle of the jet is discussed in relation to the Coanda effect of the jet in the meniscus.
Solutal-convection regimes in a two-dimensional porous medium
Authors: Slim Anja C.
Published: February 2014

We numerically characterize the temporal regimes for solutal convection from almost first contact to high dissolved solute concentration in a two-dimensional ideal porous layer for Rayleigh numbers $\mathcal{R}$ between $100$ and $5\times 10^4$. The lower boundary is impenetrable. The upper boundary is saturated with dissolved solute and either impermeable or partially permeable to fluid flow. In the impermeable case, initially there is pure diffusion of solute away from the upper boundary, followed by the birth and growth of convective fingers. Eventually fingers interact and merge, generating complex downwelling plumes. Once the inter-plume spacing is sufficient, small protoplumes reinitiate on the boundary layer and are swept into the primary plumes. The flow is now in a universal regime characterized by a constant (dimensionless) dissolution flux $F=0.017$ (the rate at which solute dissolves from the upper boundary). The horizontally averaged concentration profile stretches as a simple self-similar wedge beneath a diffusive horizontal boundary layer. Throughout, the plume width broadens proportionally to $\sqrt{t}$, where $t$ is (dimensionless) time. The above behaviour is parameter independent; the Rayleigh number only controls when transition occurs to a final $\mathcal{R}$-dependent shut-down regime. For the constant-flux and shut-down regimes, we rigourously derive upscaled equations connecting the horizontally averaged concentration, vertical advective flux and plume widths. These are partially complete; a universal expression for the plume width remains elusive. We complement these governing equations with phenomenological boundary conditions based on a marginally stable diffusive boundary layer at the top and zero advective flux at the bottom. Making appropriate approximations in each regime, we find good agreement between predictions from this model and simulated results for both solutal and thermal convection. In the partially permeable upper boundary case, fluid from the convecting layer can penetrate an overlying separate-phase-solute bearing layer where it immediately saturates. The regime diagram remains almost the same as for the impermeable case, but the dissolution flux is significantly augmented. Our work is motivated by dissolution of carbon dioxide relevant to geological storage, and we conclude with a simple flux parameterization for inclusion in gravity current models and suggest that the upscaled equations could lay the foundation for accurate inclusion of dissolution in reservoir simulators.
Decay of turbulence generated by a square-fractal-element grid
Authors: Hearst R. J. , Lavoie P.
Published: February 2014

A novel square-fractal-element grid was designed in order to increase the downstream measurement range of fractal grid experiments relative to the largest element of the grid. The grid consists of a series of square fractal elements mounted to a background mesh with spacing$L_0 = 100\, {\rm mm}$. Measurements were performed in the region$3.5 \le x/L_0 \le 48.5$, which represents a significant extension to the$x/L_0 < 20$of previously reported square fractal grid measurements. For the region$x/L_0 \gtrsim 24$it was found that a power-law decay region following$\langle {q}^2 \rangle \sim (x - x_0)^m$exists with decay exponents of$m = -1.39$and$-1.37$at$\mathit{Re}_{L_0} = 57\, 000$and$65\, 000$, respectively. This agrees with decay values previously measured for regular grids ($-1 \gtrsim m \gtrsim -1.4$). The turbulence in the near-grid region,$x/L_0 < 20$, is shown to be inhomogeneous and anisotropic, in apparent contrast with previous fractal grid measurements. Nonetheless, power-law fits to the decay of turbulent kinetic energy in this region result in$m = -2.79$, similar to$m \approx -2.5$recently reported by Valente & Vassilicos (J. Fluid Mech., vol. 687, 2011, pp. 300–340) for space-filling square fractals. It was also found that$C_\epsilon $is approximately constant for$x/L_0 \ge 25$, while it grows rapidly for$x/L_0 < 20$. These results reconcile previous fractal-generated turbulence measurements with classical grid turbulence measurements.
Processing effects in linguistic judgment data: (super-)additivity and reading span scores
Authors: HOFMEISTER PHILIP , CASASANTO LAURA STAUM , SAG IVAN A.
Published: February 2014

abstract

Linguistic acceptability judgments are widely agreed to reflect constraints on real-time language processing. Nonetheless, very little is known about how processing costs affect acceptability judgments. In this paper, we explore how processing limitations are manifested in acceptability judgment data. In a series of experiments, we consider how two factors relate to judgments for sentences with varying degrees of complexity: (1) the way constraints combine (i.e., additively or super-additively), and (2) the way a comprehender’s memory resources influence acceptability judgments. Results indicate that multiple sources of processing difficulty can combine to produce super-additive effects, and that there is a positive linear relationship between reading span scores and judgments for sentences whose unacceptability is attributable to processing costs. These patterns do not hold for sentences whose unacceptability is attributable to factors other than processing costs, e.g., grammatical constraints. We conclude that tests of (super)-additivity and of relationships to reading span scores can help to identify the effects of processing difficulty on acceptability judgments, although these tests cannot be used in contexts of extreme processing difficulty.
Variability in Ultra-luminous X-ray Sources
Authors: Webb N. A. , Cseh D. , Kirsten F.
Published: February 2014

Many upcoming surveys, particularly in the radio and optical domains, are designed to probe either the temporal and/or the spatial variability of a range of astronomical objects. In the light of these high resolution surveys, we review the subject of ultra-luminous X-ray (ULX) sources, which are thought to be accreting black holes for the most part. We also discuss the sub-class of ULXs known as the hyper-luminous X-ray sources, which may be accreting intermediate mass black holes. We focus on some of the open questions that will be addressed with the new facilities, such as the mass of the black hole in ULXs, their temporal variability and the nature of the state changes, their surrounding nebulae, and the nature of the region in which ULXs reside.
Prioritizing conservation of tropical dry forests in the Pacific
Authors: Gillespie Thomas W. , O'Neill Kristin , Keppel Gunnar , Pau Stephanie , Meyer Jean-Yves , Price Jonathan P. , Jaffré Tanguy
Published: February 2014

To identify forests of high priority for conservation in tropical dry forests of New Caledonia, Fiji, the Marquesas and Hawaii, we examined patterns of woody plant species richness (total, native and endemic) and threatened species (IUCN categorization and density) at the stand level, using Gentry's transect method. There were associations between total, native and endemic plant species richness in all four Pacific dry forest regions but we found no significant association with the presence or density of species listed on the IUCN Red List. Dry forests in New Caledonia and Hawaii merit the highest conservation priority in the Pacific, based on level of endemism and number of threatened species. The study sites that merit high conservation priority are Metzdorf, Nekoro and Pindai, in New Caledonia, Kokee and Kaupulehu, in Hawaii, and Vatia, in Fiji. New Caledonia and Fiji have a small dry forest extent and protected area extent compared with other dry forests in biodiversity hotspots. Although we identified priority areas for dry forest conservation, more comparative plot data, presence/absence data in fragments and regional geographical data are needed to adequately manage and protect dry forests in the Pacific.
Effects of age and language on co-speech gesture production: an investigation of French, American, and Italian children's narratives
Authors: COLLETTA JEAN-MARC , GUIDETTI MICHÈLE , CAPIRCI OLGA , CRISTILLI CARLA , DEMIR OZLEM ECE , KUNENE-NICOLAS RAMONA N. , LEVINE SUSAN
Published: February 2014

The aim of this paper is to compare speech and co-speech gestures observed during a narrative retelling task in five- and ten-year-old children from three different linguistic groups, French, American, and Italian, in order to better understand the role of age and language in the development of multimodal monologue discourse abilities. We asked 98 five- and ten-year-old children to narrate a short, wordless cartoon. Results showed a common developmental trend as well as linguistic and gesture differences between the three language groups. In all three languages, older children were found to give more detailed narratives, to insert more comments, and to gesture more and use different gestures – specifically gestures that contribute to the narrative structure – than their younger counterparts. Taken together, these findings allow a tentative model of multimodal narrative development in which major changes in later language acquisition occur despite language and culture differences.
Differential effects of reduced water potential on the germination of floodplain grassland species indicative of wet and dry habitats
Authors: Ludewig Kristin , Zelle Bianka , Eckstein R. Lutz , Mosner Eva , Otte Annette , Donath Tobias W.
Published: February 2014

Floodplain meadow ecosystems are characterized by high water level fluctuations and highly variable soil water potentials. Additionally, climate change scenarios indicate an increasing risk for summer drought along the northern Upper Rhine and the Middle Elbe River, Germany. While adult plants often persist even after strong changes in water availability, early life phases, such as seed germination and seedling establishment, might be more vulnerable. Therefore we tested whether reduced soil water potentials will affect the germination of meadow species and whether the response varies between (1) forbs indicative of wet and dry habitats and (2) seeds originating from sites along the rivers Elbe and Rhine. We exposed seeds of 20 floodplain meadow species with different moisture requirements from five plant families to a water potential gradient ranging from 0 to − 1.5 MPa. While across species germination percentage and synchrony decreased, germination time increased at reduced water potentials. Germination of the species indicative of dry habitats decreased more strongly, was slower and less synchronous at reduced water potentials than that of species indicative of wet habitats. Seeds from sites along the rivers Elbe and Rhine did not differ in their germination characteristics. We propose that species of wet sites follow an all-or-nothing-strategy with fast and synchronous germination to maximize competitive advantages, betting on a high probability of moist conditions for establishment (optimists). In contrast, species from dry sites appear to follow a bet-hedging strategy with a moisture-sensing mechanism for unsuitable conditions (pessimists), resulting in a slower and less synchronous germination.
It Is Hard to Get There without a Guide
Authors: CAPLAN ARTHUR
Published: February 2014

In this series of essays, The Road Less Traveled, noted bioethicists share their stories and the personal experiences that prompted them to pursue the field. These memoirs are less professional chronologies and more descriptions of the seminal touchstone events and turning points that led—often unexpectedly—to their career path.
White Matter and Cognitive Decline in Aging: A Focus on Processing Speed and Variability
Authors: Nilsson Jonna , Thomas Alan J. , O'Brien John T. , Gallagher Peter
Published: February 2014

White matter (WM) change plays an important role in age-related cognitive decline. In this review, we consider methodological advances with particular relevance to the role of WM in age-related changes in processing speed. In this context, intra-individual variability in processing speed performance has emerged as a sensitive proxy of cognitive and neurological decline while neuroimaging techniques used to assess WM change have become increasingly more sensitive. Together with a carefully designed task protocol, we emphasize that the combined implementation of intra-individual variability and neuroimaging techniques hold promise for specifying the WM-processing speed relationship with implications for normative and clinical samples. (JINS, 2014,20, 1–6)
The impact of environmental policies on productivity and market competition
Authors: Sadeghzadeh Javad
Published: February 2014

While a large body of the literature on environmental policies has focused on the productivity impacts of regulations, less attention has been given to the link between environmental policies and market competition. In this paper, I develop a tractable model that incorporates variable mark-ups to study how a competitive environment is affected by environmental policies in a market with firm heterogeneity and endogenous abatement technology choice. The findings of this study are consistent with the Porter Hypothesis in the sense that environmental regulations motivate abatement technology adoption and enhance productivity and environmental quality. However, the productivity gain is mainly driven by reallocation of resources across firms rather than the induced abatement technological change. Tougher regulations harm the competitive environment by increasing average prices and market concentration. Social welfare also drops because in the absence of strong competition fewer variates are produced in equilibrium.
Achtsamkeitsbasierte Psychotherapie – Chancen und Grenzen der dritten Generation der Verhaltenstherapie
Authors: Heidenreich Thomas , Michalak Johannes
Published: February 2014

Fragestellung: Der Artikel stellt wesentliche Ansatzpunkte achtsamkeitsbasierter Psychotherapie dar und stellt das Konzept einer „dritten Welle“ der Verhaltenstherapie vor. Inhaltsübersicht: Zentrale Ansätze, die sich der „dritten Welle“ zuordnen lassen (Achtsamkeitsbasierte Stresssreduktion, achtsamkeitsbasierte kognitive Therapie, Acceptance and Commitment Therapy, Dialektisch-behaviorale Therapie) sowie der Stand zur Wirksamkeitsforschung werden kurz vorgestellt. Im Anschluss daran werden Chancen und Gefahren achtsamkeitsbasierter Ansätze diskutiert. Schlussfolgerungen: Achtsamkeitsbasierte Interventionen stellen für die Psychotherapie allgemein und für den Suchtbereich interessante Perspektiven dar. Mögliche Gefahren der Umsetzung achtsamkeitsbasierter Verfahren sollten berücksichtigt werden.
Super sub-wavelength patterns in photon coincidence detection
Authors: Liu Ruifeng , Zhang Pei , Zhou Yu , Gao Hong , Li Fuli
Published: February 2014

High-precision measurements implemented with light are desired in all fields of science. However, light acts as a wave and the Rayleigh criterion in classical optics yields a diffraction limit that prevents obtaining a resolution smaller than the wavelength. Sub-wavelength interference has potential application in lithography because it beats the classical Rayleigh resolution limit. Here, we carefully study second-order correlation theory to establish the physics behind sub-wavelength interference in photon coincidence detection. A Young's double slit experiment with pseudo-thermal light is performed to test the second-order correlation pattern. The results show that when two point detectors are scanned in different ways, super sub-wavelength interference patterns can be obtained. We then provide a theoretical explanation for this surprising result and demonstrate that this explanation is also suitable for the results found for entangled light. Furthermore, we discuss the limitations of these types of super sub-wavelength interference patterns in quantum lithography.
Serotonin-2C receptor involved serotonin-induced Ca2+ mobilisations in neuronal progenitors and neurons in rat suprachiasmatic nucleus
Authors: Takeuchi Kouhei , Mohammad Shahid , Ozaki Tomoya , Morioka Eri , Kawaguchi Kaori , Kim Juhyon , Jeong Byeongha , Hong Jin Hee , Lee Kyoung J. , Ikeda Masayuki
Published: February 2014

The hypothalamic suprachiasmatic nucleus (SCN), the central circadian pacemaker in mammals, undergoes serotonergic regulation, but the underlying mechanisms remain obscure. Here, we generated a subclone of an SCN progenitor cell line expressing Ca2+ sensors (SCN2.2YC) and compared its 5-HT receptor signalling with that of rat SCN neurons in brain slices. SCN2.2YC cells expressed 5-HT1A/2A/2B/2C, but not 5A/7, while all six subtypes were expressed in SCN tissues. High K+ or 5-HT increased cytosolic Ca2+ in SCN2.2YC cells. The 5-HT responses were inhibited by ritanserin and SB-221284, but resistant to WAY-100635 and RS-127445, suggesting predominant involvement of 5-HT2C for Ca2+ mobilisations. Consistently, Ca2+ imaging and voltage-clamp electrophysiology using rat SCN slices demonstrated post-synaptic 5-HT2C expression. Because 5-HT2C expression was postnatally increased in the SCN and 5-HT-induced Ca2+ mobilisations were amplified in differentiated SCN2.2YC cells and developed SCN neurons, we suggest that this signalling development occurs in accordance with central clock maturations.
Negative consequences of glacial turbidity for the survival of freshwater planktonic heterotrophic flagellates
Authors: Sommaruga Ruben , Kandolf Georg
Published: February 2014

Heterotrophic (phagotrophic) flagellates are key components of planktonic food webs in freshwater and marine ecosystems because they are the main consumers of bacteria. Although they are ubiquitous in aquatic ecosystems, they were numerically undetectable in turbid glacier-fed lakes. Here we show that glacial particles had negative effects on the survival and growth of heterotrophic flagellates. The effect of glacial particles was concentration-dependent and was caused by their interference with bacterial uptake rather than by physical damage. These results are the first to reveal why establishment of heterotrophic flagellates populations is hindered in very turbid glacial lakes. Because glaciers are vanishing around the world, recently formed turbid meltwater lakes represent an excellent opportunity to understand the environmental conditions that probably shaped the establishment of lake communities at the end of the last glaciation.
Hollow hydroxyapatite spheres fabrication with three-dimensional hydrogel template
Authors: Li Zhiyong , Wen Tao , Su Yunlan , Wei Xiaoxiao , He Changcheng , Wang Dujin
Published: February 2014

Flower-like porous hollow HAp spheres were obtained by diffusion of phosphate ions into PAAm hydrogels containing calcium ions by both an electrophoresis approach and an ion diffusion method.
Revisiting the role of exact exchange in DFT spin-state energetics of transition metal complexes
Authors: Radoń Mariusz
Published: February 2014

Sensitivity of DFT spin-state energetics to exact exchange is rooted in the description of metal–ligand bonding.
Significant roles of mesostructure and basic modifier for ordered mesoporous Ni/CaO–Al2O3 catalyst towards CO2 reforming of CH4
Authors: Xu Leilei , Miao Zhichao , Song Huanling , Chen Wei , Chou Lingjun
Published: February 2014

The significant roles of mesostructure and basic modifier in improving the catalytic performance of dry reforming were investigated.
Hydrogen sulfide donors in research and drug development
Authors: Song Zhi Jian , Ng Mei Ying , Lee Zheng-Wei , Dai Weilu , Hagen Thilo , Moore Philip K. , Huang Dejian , Deng Lih-Wen , Tan Choon-Hong
Published: February 2014

This review summarized most of the H2S donors such as inorganic compounds, natural products, anethole trithione derivatives and synthetic compounds used in research and drug development. These special bioactivities provided us some effective strategies for antiphlogosis, cancer therapy, cardiovascular protection and so on.
Multitarget-directed resveratrol derivatives: anti-cholinesterases, anti-β-amyloid aggregation and monoamine oxidase inhibition properties against Alzheimer's disease
Authors: Pan Long-Fei , Wang Xiao-Bing , Xie Sai-Sai , Li Su-Yi , Kong Ling-Yi
Published: February 2014

Resveratrol derivatives were designed and synthesized as multitarget-directed agents for treating AD, and 6r was a balanced inhibitor toward all the tested targets.
Constructing hybrid porous polymers from cubic octavinylsilsequioxane and planar halogenated benzene
Authors: Wang Dengxu , Yang Wenyan , Feng Shengyu , Liu Hongzhi
Published: February 2014

Hybrid porous polymers derived from cubic octavinylsilsequioxane and planar halogenated benzene monomers exhibit high thermal stability, tunable porosities and potential applications in carbon dioxide storage.
Band alignment by ternary crystalline potential-tuning interlayer for efficient electron injection in quantum dot-sensitized solar cells
Authors: Chen Zhenhua , Peng Wenqin , Zhang Kun , Zhang Jing , Yang Xudong , Numata Youhei , Han Liyuan
Published: February 2014

A facile way to enhance electron injection efficiency of solar cells by interlayer CdS1−xSex quantum dots has been developed.
A dual-mode fluorescence “turn-on” biosensor based on an aggregation-induced emission luminogen
Authors: Song Zhegang , Hong Yuning , Kwok Ryan T. K. , Lam Jacky W. Y. , Liu Bin , Tang Ben Zhong
Published: February 2014

A dual-mode fluorescent biosensor based on TPE-TEG-PA is developed for protamine quantification and alkaline phosphatase activity assay.
Magnetic nanosensors optimized for rapid and reversible self-assembly
Authors: Rodriguez Elisenda , Lelyveld Victor S. , Atanasijevic Tatjana , Okada Satoshi , Jasanoff Alan
Published: February 2014

Magnetic nanoparticle-based sensors for MRI have been accelerated to a timescale of seconds using densely-functionalized particles of small size.