bluuebunny/crossref_metadata_2025 huggingface dataset:
Interaction of oxovanadium(iv)–salphen complexes with bovine serum albumin and their cytotoxicity against cancer
Authors: Gomathi Sankareswari Velusamy , Vinod Devaraj , Mahalakshmi Ayyasamy , Alamelu Meena , Kumaresan Ganesan , Ramaraj Ramasamy , Rajagopal Seenivasan
Published: November 2013

An oxovanadium(iv)–salphen complex acts as a probe for bovine serum albumin and shows cytotoxicity against cancer cells.
A highly porous three-dimensional aluminum phosphonate with hexagonal channels: synthesis, structure and adsorption properties
Authors: Tang Si-Fu , Cai Jin-Jun , Li Liang-Jun , Lv Xiao-Xia , Wang Chao , Zhao Xue-Bo
Published: November 2013

A 3D porous aluminum trisphosphonate containing large hexagonal channels displays a fast and relatively high uptake of H2, N2 and CO2.
Determination of glucose flux in live myoblasts by microfluidic nanosensing and mathematical modeling
Authors: Zambon Alessandro , Zoso Alice , Luni Camilla , Frommer Wolf B. , Elvassore Nicola
Published: November 2013

Quantitative dissection of dynamic glucose handling processes in live myoblasts without use of glucose analogs and radioactive hexoses.
Live human nasal epithelial cells (hNECs) on chip for in vitro testing of gaseous formaldehyde toxicity via airway delivery
Authors: Wang Wei , Yan Yan , Li Chun Wei , Xia Huan Ming , Chao Siew Shuen , Wang De Yun , Wang Zhi Ping
Published: November 2013

The live human upper airway was mimicked on a microfluidic platform for toxicology testingviaairway delivery.
Development of n-type organic semiconductors for thin film transistors: a viewpoint of molecular design
Authors: Gao Xike , Hu Yunbin
Published: November 2013

More than nine molecular design strategies with >120 representative n-type organic semiconductors are summarized and analyzed.
Key Information Technology and Management Issues 2012-2013: An International Study
Authors: Luftman Jerry , Zadeh Hossein S , Derksen Barry , Santana Martin , Rigoni Eduardo Henrique , Huang Zhengwei (David)
Published: November 2013

The importance of the impact of IT for organizations around the world, especially in light of a very slow recovery from the global financial crisis, has amplified the need to provide a better understanding of the specific geographic similarities and differences in IT managerial and technical trends. Identifying these influential factors is one thing; the paper also looks at the challenges in addressing them, taking into account both local responsiveness and global pressures. By comparing and contrasting IT trends from different geographies, this paper presents important local and international factors, including management concerns, influential technologies, budgets/spending, and organizational considerations). In addition these trends help to prepare IT leaders for the challenges that await them. The IT trends also serve as an indicator as the respective geographies address their difficult economic environments. The research is based on data from four geographic regions, namely United States, Europe, Asia, and Latin America. The same questionnaire (albeit translated for the respective respondents), based on the lead author's well-respected and long-running Society for Information Management survey, was applied across the geographies. This paper presents the major findings based on survey responses from 787 organizations (195 U.S., 360 European, 55 Asian, 41 Australia, and 136 Latin) in 2012. The top five management concerns were: (1) Business productivity & cost reduction, (2) Business & IT alignment / integration / fusion, (3) Business agility & speed to market, (4) Business process management/reengineering, and (5) IT cost reduction. The five most influential technologies were: (1) Business intelligence, (2) Cloud computing, (3) Enterprise resource planning, (4) Apps developments, and (5) Customer relationship management. Overall, the paper finds that while the economic climate is improving at different rates around the globe - albeit at a slower pace than anticipated - ITs role continues to evolve as it provides organizations with a fundamental vehicle for reducing business expenses and new opportunities for increasing revenues.
Automatic computer procedure for generating exact and analytical kinetic energy operators based on the polyspherical approach: General formulation and removal of singularities
Authors: Ndong Mamadou , Nauts André , Joubert-Doriol Loïc , Meyer Hans-Dieter , Gatti Fabien , Lauvergnat David
Published: November 2013

We present new techniques for an automatic computation of the kinetic energy operator in analytical form. These techniques are based on the use of the polyspherical approach and are extended to take into account Cartesian coordinates as well. An automatic procedure is developed where analytical expressions are obtained by symbolic calculations. This procedure is a full generalization of the one presented in Ndong et al., [J. Chem. Phys. 136, 034107 (2012)]. The correctness of the new implementation is analyzed by comparison with results obtained from the TNUM program. We give several illustrations that could be useful for users of the code. In particular, we discuss some cyclic compounds which are important in photochemistry. Among others, we show that choosing a well-adapted parameterization and decomposition into subsystems can allow one to avoid singularities in the kinetic energy operator. We also discuss a relation between polyspherical and Z-matrix coordinates: this comparison could be helpful for building an interface between the new code and a quantum chemistry package.
Interpolatability distinguishes LOCC from separable von Neumann measurements
Authors: Childs Andrew M. , Leung Debbie , Mančinska Laura , Ozols Maris
Published: November 2013

Local operations with classical communication (LOCC) and separable operations are two classes of quantum operations that play key roles in the study of quantum entanglement. Separable operations are strictly more powerful than LOCC, but no simple explanation of this phenomenon is known. We show that, in the case of von Neumann measurements, the ability to interpolate measurements is an operational principle that sets apart LOCC and separable operations.
Oblique wave trapping by porous and flexible structures in a two-layer fluid
Authors: Behera H. , Mandal S. , Sahoo T.
Published: November 2013

Trapping of obliquely incident surface waves by permeable flexible barriers placed near a vertical rigid wall in a two-layer fluid having free surface and an interface is studied for both surface-piercing and bottom-standing partial barriers. For the surface-piercing permeable flexible barrier, the barrier is assumed to be fixed near the free surface and is free at the submerged end. On the other hand, for the bottom standing permeable flexible barrier, the barrier is assumed to be fixed at the bottom and the other end is free. As special cases of the permeable flexible barrier, the results associated with surface-piercing and bottom-standing permeable membrane barriers are obtained by assuming that the two ends of the barriers are fixed. Appropriate continuity conditions are used to deal with the interface-piercing flexible/membrane barriers. The mathematical problem is handled for solution using a generalized orthogonal relation suitable for two-layer fluid along with the least square approximation method. Explicit relations are derived to ensure full reflection by porous flexible barriers of any configuration placed near a vertical rigid wall for waves in surface and internal modes, which are validated through numerical computations in various cases. The effect of critical angle of incidence on wave reflection and trapping by barriers, surface and interface wave elevations, deflection of the flexible barrier under wave action, pressure distribution on the barrier, wave loads on barrier and rigid wall are analyzed. The finding of the present study is likely to play a significant role in the design of marine facilities with less wave force on the infrastructure. The present concept and methodology can be easily extended to similar problems in acoustic-structure interactions.
Flow structures and their contribution to turbulent dispersion in a randomly packed porous bed based on particle image velocimetry measurements
Authors: Patil Vishal A. , Liburdy James A.
Published: November 2013

An experimental study was undertaken to explore the evolution of flow structures and their characteristics within a randomly packed porous bed with particular attention to evaluating turbulent scalar dispersion. A low aspect ratio bed of 4.67 (bed width to spherical solid phase particle diameter) with fluid phase refractive index matched to that of the solid phase was used in order to obtain time resolved two component particle image velocimetry data. Results are based on detailed velocity vector maps obtained at selected pores near the bed center. Pore, or large scale, regions that are associated with the mean flow were identified based on Reynolds decomposed velocity fields, while smaller scale structures embedded within pore scale regions were identified and quantified by combining large eddy scale decomposition and swirling strength analysis. The velocity maps collected in distinctive pore geometries showed presence of three types of flow regions that display very different mean flow conditions, described as regions with tortuous channel like flow, high fluid momentum jet like regions, and low fluid momentum recirculating regions. The major portion of pore space is categorized as tortuous channel flow. Time series of instantaneous velocity field maps were used to identify mean and turbulent flow structures based on their spatial scales in the different regions. Even though regions exhibit varied Eulerian statistics, they show very similar eddy characteristics such as spinning rate and number density. The integral scale eddy structures show nearly a linear rate of increase in their rotation rate with increasing pore Reynolds number, indicating a linear decrease in their time scales. The convective velocities of these eddies are shown to reach an asymptotic limit at high pore Reynolds numbers, unique for each flow region. Detailed Eulerian statistics for the identified flow regions are presented and are used to predict mechanical dispersion through the use of estimated Lagrangian statistics. Contributions from each of the flow regions are presented and the recirculating regions are shown to contribute most to the overall longitudinal dispersion, whereas the tortuous channel regions contribute most to the transverse dispersion. The overall dispersion estimates agree well with global data in the limit of high Schmitt number.
Origin of parameter degeneracy and molecular shape relationships in geometric-flow calculations of solvation free energies
Authors: Daily Michael D. , Chun Jaehun , Heredia-Langner Alejandro , Wei Guowei , Baker Nathan A.
Published: November 2013

Implicit solvent models are important tools for calculating solvation free energies for chemical and biophysical studies since they require fewer computational resources but can achieve accuracy comparable to that of explicit-solvent models. In past papers, geometric flow-based solvation models have been established for solvation analysis of small and large compounds. In the present work, the use of realistic experiment-based parameter choices for the geometric flow models is studied. We find that the experimental parameters of solvent internal pressure p = 172 MPa and surface tension γ = 72 mN/m produce solvation free energies within 1 RT of the global minimum root-mean-squared deviation from experimental data over the expanded set. Our results demonstrate that experimental values can be used for geometric flow solvent model parameters, thus eliminating the need for additional parameterization. We also examine the correlations between optimal values of p and γ which are strongly anti-correlated. Geometric analysis of the small molecule test set shows that these results are inter-connected with an approximately linear relationship between area and volume in the range of molecular sizes spanned by the data set. In spite of this considerable degeneracy between the surface tension and pressure terms in the model, both terms are important for the broader applicability of the model.
Studies on low energy beam transport for high intensity high charged ions at IMP
Authors: Yang Y. , Sun L. T. , Hu Q. , Cao Y. , Lu W. , Feng Y. C. , Fang X. , Zhang X. Z. , Zhao H. W. , Xie D. Z.
Published: November 2013

Superconducting Electron Cyclotron Resonance ion source with Advanced design in Lanzhou (SECRAL) is an advanced fully superconducting ECR ion source at IMP designed to be operational at the microwave frequency of 18–24 GHz. The existing SECRAL beam transmission line is composed of a solenoid lens and a 110° analyzing magnet. Simulations of particle tracking with 3D space charge effect and realistic 3D magnetic fields through the line were performed using particle-in-cell code. The results of the beam dynamics show that such a low energy beam is very sensitive to the space charge effect and significantly suffers from the second-order aberration of the analyzing magnet resulting in large emittance. However, the second-order aberration could be reduced by adding compensating sextupole components in the beam line. On this basis, a new 110° analyzing magnet with relatively larger acceptance and smaller aberration is designed and will be used in the design of low energy beam transport line for a new superconducting ECR ion source SECRAL-II. The features of the analyzer and the corresponding beam trajectory calculation will be detailed and discussed in this paper.
Improving efficiency of negative ion production in ion source with saddle antenna
Authors: Dudnikov V. , Johnson R. P. , Murrey S. , Pinnisi T. , Piller C. , Santana M. , Stockli M. , Welton R. , Johnson C. , Turvey M.
Published: November 2013

Extraction of negative ions from a saddle antenna radio-frequency surface plasma source is considered. Several versions of new plasma generators with different antennas and magnetic field configurations were tested in the smal Oak Ridge National Laboratory Spallation Neutron Source Test Stand. The efficiency of positive ion generation in plasma has been improved to 200 mA/cm2 kW from 2.5 mA/cm2 kW. A small oven was developed for cesiation by cesium compounds and alloy decomposition. After cesiation, a current of negative ions to the collector was increased from 1 mA to 10 mA with 1.5 kW RF power in the plasma and longitudinal magnetic field Bl ∼ 250 G. The specific efficiency of H− production was increased to 20 mA/cm2 kW from 2.5 mA/cm2 kW.
Capacitance enhancement via electrode patterning
Authors: Ho Tuan A. , Striolo Alberto
Published: November 2013

The necessity of increasing the energy density in electric double layer capacitors to meet current demand is fueling fundamental and applied research alike. We report here molecular dynamics simulation results for aqueous electrolytes near model electrodes. Particular focus is on the effect of electrode patterning on the structure of interfacial electrolytes, and on the potential drop between the solid electrodes and the bulk electrolytes. The latter is estimated by numerically integrating the Poisson equation using the charge densities due to water and ions accumulated near the interface as input. We considered uniform and patterned electrodes, both positively and negatively charged. The uniformly charged electrodes are modeled as graphite. The patterned ones are obtained by removing carbon atoms from the top-most graphene layer, yielding nanoscopic squares and stripes patterns. For simplicity, the patterned electrodes are effectively simulated as insulators (the charge remains localized on the top-most layer of carbon atoms). Our simulations show that the patterns alter the structure of water and the accumulation of ions at the liquid-solid interfaces. Using aqueous NaCl solutions, we found that while the capacitance calculated for three positively charged electrodes did not change much, that calculated for the negatively charged electrodes significantly increased upon patterning. We find that both water structure and orientation, as well as ion accumulation affect the capacitance. As electrode patterning affects differently water structure and ion accumulation, it might be possible to observe ion-specific effects. These results could be useful for advancing our understanding of electric double layer capacitors, capacitive desalination processes, as well as of fundamental interfacial electrolytes properties.
Transition to turbulence in slowly divergent pipe flow
Authors: Peixinho Jorge , Besnard Hugues
Published: November 2013

The results of a combined experimental and numerical study of the flow in slowly diverging pipes are presented. Interestingly, an axisymmetric conical recirculation cell has been observed. The conditions for its existence and the length of the cell are simulated for a range of diverging angles. There is a critical velocity for the appearance of this state. When the flow rate increases further, a subcritical transition for localized turbulence arises. The transition and relaminarization experiments described here quantify the extent of turbulence. The findings suggest that the transition scenario in slowly diverging pipes is a combination of stages similar to those observed in sudden expansions and in straight circular pipe flow.
Advanced performance and scalability of Si nanowire field-effect transistors analyzed using noise spectroscopy and gamma radiation techniques
Authors: Li J. , Vitusevich S. A. , Petrychuk M. V. , Pud S. , Offenhäusser A. , Danilchenko B. A.
Published: November 2013

High-quality Si nanowire field effect transistors (FETs) were fabricated using thermal nanoimprint and chemical wet etching technologies. FET structures of different lengths demonstrate high carrier mobility with values of about 750 cm2/Vs and low volume densities of active traps in the dielectric layers of 5 × 1017 cm−3 eV−1. We investigated the transport properties of these n-type channel structures using low-frequency noise spectroscopy before and after gamma radiation treatment. Before gamma irradiation, FET structures with lengths of less than 4 μm exhibited noise from contact regions with 1/(L2) dependence for the relative 1/f noise. After gamma radiation, the spectra reflected the priority of channel noise with 1/L dependence for all samples. The transport characteristics show that the fabricated nanowire FETs improved scalability, decreased parameter scattering, and increased stability after treatment. The results demonstrate that these nanowire FETs are promising for nanoelectronic and biosensor applications due to the cost-efficient technology and advanced performance of FETs with improved stability and reliability.
Dissipative kinetic Alfvén solitary waves resulting from viscosity
Authors: Choi C.-R. , Woo M.-H. , Kang S.-B. , Min K.-W. , Hwang J. , Park Y.-D.
Published: November 2013

Nonlinear small-amplitude kinetic Alfvén solitary waves (KASWs) are investigated with their “anomalous” kinetic viscosity effect on electrons. It is found that the structure of a hump-type KASW solution develops into a shock-type (or double layer) KASW solution for large amplitude KASWs when viscosity exists. For small amplitude KASWs, the Korteweg-de Vries (KdV) equation with an approximate pseudopotential was solved, and it is found that the hump-type KASWs develop into oscillating shock-type (kink-type) KASWs. It is also found that the oscillating scale of this structure is related to the propagation velocity and plasma beta, while the damping scale is inversely proportional to the viscosity.
Doped semiconductor nanocrystal junctions
Authors: Borowik Ł. , Nguyen-Tran T. , Roca i Cabarrocas P. , Mélin T.
Published: November 2013

Semiconductor junctions are the basis of electronic and photovoltaic devices. Here, we investigate junctions formed from highly doped (ND≈1020−1021cm−3) silicon nanocrystals (NCs) in the 2–50 nm size range, using Kelvin probe force microscopy experiments with single charge sensitivity. We show that the charge transfer from doped NCs towards a two-dimensional layer experimentally follows a simple phenomenological law, corresponding to formation of an interface dipole linearly increasing with the NC diameter. This feature leads to analytically predictable junction properties down to quantum size regimes: NC depletion width independent of the NC size and varying as ND−1/3, and depleted charge linearly increasing with the NC diameter and varying as ND1/3. We thus establish a “nanocrystal counterpart” of conventional semiconductor planar junctions, here however valid in regimes of strong electrostatic and quantum confinements.
Geometric factors in the magnetoresistance of n-doped InAs epilayers
Authors: Sun Jian , Soh Yeong-Ah , Kosel Jürgen
Published: November 2013

We investigate the magnetoresistance (MR) effect in n-doped InAs and InAs/metal hybrid devices with geometries tailored to elucidate the physical mechanism and the role of geometry in the MR. Despite the isotropic Fermi surface in InAs, we observe a strong intrinsic MR in the InAs epilayer due to the existence of a surface conducting layer. Experimental comparison confirms that the extraordinary MR in the InAs/metal hybrids outperforms the orbital MR in the Corbino disk in terms of both the MR ratio and the magnetic field resolution. The results also indicate the advantage of a two-contact configuration in the hybrid devices over a four-contact one with respect to the magnetic field resolution. This is in contrast to previously reported results, where performance was evaluated in terms of the MR ratio and a four-contact configuration was found to be optimal. By applying Kohler's rule, we find that at temperatures above 75 K the extraordinary MR violates Kohler's rule, due to multiple relaxation rates, whereas the orbital MR obeys it. This finding can be used to distinguish the two geometric effects, the extraordinary MR and the orbital MR, from each other.
Composition dependence of band alignments in GaxIn1−xAsySb1−y heterojunctions lattice matched to GaSb and InAs
Authors: Shim Kyurhee
Published: November 2013

A theoretical model utilizing a universal tight binding method and a correlated function expansion technique is presented to calculate the valence band maximum (VBM) and the conduction band minimum (CBM) of the binary (GaAs, InAS, GaSb, and InSb) and quaternary alloy GaxIn1−xAsySb1−y systems. By organizing the relative positions of the VBM and CBM between semiconductors, the band alignments and band types in the heterojunctions are determined. A straddling (type-I) band alignment in InAs/GaAs, InSb/GaAs, and GaSb/InSb, staggered (type-II) band alignment in GaSb/GaAs, and broken (type-III) band alignment in InSb/InAs and InAs/GaSb are found respectively. In addition, the compositional variations of VBM, CBM, valence band offset, conduction band offset, and band type for the alloy GaxIn1−xAsySb1−y lattice matched on GaSb and InAs are obtained as increasing the composition x. A pronounced upward bowing for the VBM and a very slight upward bowing (almost linear) for CBM are found, respectively. By controlling the compositions (x, y), band type transitions occur. The GaxIn1−xAsySb1−y heterojunctions lattice matched to GaSb changes their band types from type-III at x∼0→ to type-II at x = 0.07, and → to type-I at x = 0.38. In contrast, the GaxIn1−xAsySb1−y heterojunctions lattice matched to InAs changes their band types from type-II x∼0→ to type-III at x = 0.32. Reasonable agreement is obtained between our theoretical results and existing experimental data.
Charge asymmetry in rovibrationally excited HD+ determined using explicitly correlated all-particle Gaussian functions
Authors: Kirnosov Nikita , Sharkey Keeper L. , Adamowicz Ludwik
Published: November 2013

Very accurate non-Born-Oppenheimer quantum-mechanical calculations are performed to determine the average values of the interparticle distances and the proton-deuteron density function for the rovibrationally excited HD+ ion. The states corresponding to excitations to all bound vibrational states (v = 0, …, 22) and simultaneously excited to the first excited rotational state (N = 1) are considered. To describe each state up to 8000 explicitly correlated all-particle Gaussian functions are used. The nonlinear parameters of the Gaussians are variationally optimized using a procedure that employs the analytical energy gradient determined with respect to these parameters. The results show an increasing asymmetry in the electron distribution with the vibrational excitation as the electron density shifts towards deuteron and away from the proton.
The extraordinary role of the AlN interlayer in growth of AlN sputtered on Ti electrodes
Authors: Tran A. T. , Pandraud G. , Tichelaar F. D. , Nguyen M. D. , Schellevis H. , Sarro P. M.
Published: November 2013

The structure of AlN layers grown on Ti with and without an AlN interlayer between the Si substrate and the Ti layer is investigated. The AlN grains take over the orientation of the Ti columnar grains in both cases. Surprisingly, the Ti grains do not take over completely the orientations of the AlN grains of the interlayer, and show the same columnar grain structure as the sample without interlayer. Hence, the structure of the AlN top layer is independent of the presence of an AlN interlayer below the Ti layer and is mainly determined by the Ti layer microstructure.
Ultra-low power operation of self-heated, suspended carbon nanotube gas sensors
Authors: Chikkadi Kiran , Muoth Matthias , Maiwald Verena , Roman Cosmin , Hierold Christofer
Published: November 2013

We present a suspended carbon nanotube gas sensor that senses NO2 at ambient temperature and recovers from gas exposure at an extremely low power of 2.9 μW by exploiting the self-heating effect for accelerated gas desorption. The recovery time of 10 min is two orders of magnitude faster than non-heated recovery at ambient temperature. This overcomes an important bottleneck for the practical application of carbon nanotube gas sensors. Furthermore, the method is easy to implement in sensor systems and requires no additional components, paving the way for ultra-low power, compact, and highly sensitive gas sensors.
Pseudo-binary alloying system of ZnO-AgGaO2 reducing the energy band gap of zinc oxide
Authors: Suzuki I. , Nagatani H. , Arima Y. , Kita M. , Omata T.
Published: November 2013

Pseudo-binary oxide semiconductor alloy films of (1-x)ZnO-x(AgGaO2)1/2 were fabricated using a conventional rf-magnetron sputtering. The wurtzite-type single phases were obtained in the wide composition range of x ≤ 0.33 because the terminal β-AgGaO2 that corresponds to the composition with x = 1 possesses a wurtzite-derived β-NaFeO2 structure. The energy band gap of ZnO decreased with increasing AgGaO2 concentration, falling to 2.55 eV at x = 0.33. This alloy system enables to use ZnO-based semiconductors in optoelectronic devices working in visible region.
Photo-driven autonomous hydrogen generation system based on hierarchically shelled ZnO nanostructures
Authors: Kim Heejin , Yong Kijung
Published: November 2013

A quantum dot semiconductor sensitized hierarchically shelled one-dimensional ZnO nanostructure has been applied as a quasi-artificial leaf for hydrogen generation. The optimized ZnO nanostructure consists of one dimensional nanowire as a core and two-dimensional nanosheet on the nanowire surface. Furthermore, the quantum dot semiconductors deposited on the ZnO nanostructures provide visible light harvesting properties. To realize the artificial leaf, we applied the ZnO based nanostructure as a photoelectrode with non-wired Z-scheme system. The demonstrated un-assisted photoelectrochemical system showed the hydrogen generation properties under 1 sun condition irradiation. In addition, the quantum dot modified photoelectrode showed 2 mA/cm2 current density at the un-assisted condition.
Metal-insulator transition in SrTi1−xVxO3 thin films
Authors: Gu Man , Wolf Stuart A. , Lu Jiwei
Published: November 2013

Epitaxial SrTi1−xVxO3 (0 ≤ x ≤ 1) thin films were grown on (001)-oriented (LaAlO3)0.3(Sr2AlTaO6)0.7 (LSAT) substrates using the pulsed electron-beam deposition technique. The transport study revealed a temperature driven metal-insulator transition (MIT) at 95 K for x = 0.67. The films with higher vanadium concentration (x > 0.67) were metallic corresponding to a Fermi liquid system. In the insulating phase (x < 0.67), the resistivity behavior was governed by Mott's variable range hopping mechanism. The possible mechanisms for the induced MIT are discussed, including the effects of electron correlation, lattice distortion, and Anderson localization.
Sensitization of Pr3+ ions by Eu2+ ions in CaF2 thin films deposited by evaporation
Authors: Guille A. , Pereira A. , Bensalah-Ledoux A. , Moine B. , Novotný M. , Bulíř J. , Fitl P. , Lančok J.
Published: November 2013

In the present article, we analyse the possibility of sensitizing the 3Pj levels of Pr3+ ion with Eu2+ ion in CaF2 thin film deposited by evaporation. Indeed, the forbidden nature of the 4f-4f transition of Pr3+ ion makes its absorption too weak for thin film applications, while materials doped with the Pr3+-Yb3+ couple are promising candidates for the achievement of efficient down-converter systems and could allow strong reduction of thermalization losses in silicon solar cells.
Parametric excitation of electro-mechanical vibrations of carbon nano tube with distributed surface charge
Authors: Vijay A. , Tripathi V. K.
Published: November 2013

Electromechanical vibrations of carbon nano tube (CNT), mounted on a metallic base and subjected to a sum of static and radio frequency (RF) electric fields parallel to its length, are investigated. The induced surface charge on the CNT is taken suitably distributed, following Landau and Lifshitz, so that the curved surface remains an equi-potential surface. The natural frequency of transverse vibrations of CNT, ωN depends on the dc electric field, besides the mechanical properties. When the RF frequency ω0 is close to 2ωN, the RF excites the vibrations as three mode parametric instability that saturates via nonlinearity in the restoration force.
Communication: Enhanced oxygen reduction reaction and its underlying mechanism in Pd-Ir-Co trimetallic alloys
Authors: Ham Hyung Chul , Manogaran Dhivya , Lee Kang Hee , Kwon Kyungjung , Jin Seon-ah , You Dae Jong , Pak Chanho , Hwang Gyeong S.
Published: November 2013

Based on a combined density functional theory and experimental study, we present that the electrochemical activity of Pd3Co alloy catalysts toward oxygen reduction reaction (ORR) can be enhanced by adding a small amount of Ir. While Ir tends to favorably exist in the subsurface layers, the underlying Ir atoms are found to cause a substantial modification in the surface electronic structure. As a consequence, we find that the activation barriers of O/OH hydrogenation reactions are noticeably lowered, which would be mainly responsible for the enhanced ORR activity. Furthermore, our study suggests that the presence of Ir in the near-surface region can suppress Co out-diffusion from the Pd3Co substrate, thereby improving the durability of Pd-Ir-Co catalysts. We also discuss the relative roles played by Ir and Co in enhancing the ORR activity relative to monometallic Pd catalysts.
Optical gating of perylene bisimide fluorescence using dithienylcyclopentene photochromic switches
Authors: Pärs Martti , Gräf Katja , Bauer Peter , Thelakkat Mukundan , Köhler Jürgen
Published: November 2013

The emission of millions of fluorescence photons from a chromophore is controlled by the absorption of a few tens of photons in a photochromic molecule. The parameters that determine the efficiency of this process are investigated, providing insights for the development of an all-optical gate.
City as Ideology: Reconciling the Explosion of the City Form with the Tenacity of the City Concept
Authors: Wachsmuth David
Published: November 2013

This paper is a theoretical reexamination of the traditional concept of the city in the context of urbanization processes that exceed it. Recent decades have seen a proliferation of new variations on the city concept, as well as calls to discard it altogether. I argue that both options are inadequate. The city has generally been understood as a category of analysis—a moment in urbanization processes—but might now be better understood as a category of practice: an ideological representation of urbanization processes. I substantiate this claim through an examination of three tropes of the traditional city which in material terms have been superseded in recent decades in the Global North but retain their force as ideological representations of contemporary urban spatial practice: the opposition between city and country, the city as a self-contained system, and the city as an ideal type.
Face Perception is Whole or None: Disentangling the Role of Spatial Contiguity and Interfeature Distances in the Composite Face Illusion
Authors: Laguesse Renaud , Rossion Bruno
Published: November 2013

Compelling evidence that faces are perceived holistically or configurally comes from the composite face illusion: Identical top halves of a face are perceived as being different if they are aligned with different bottom halves. The visual illusion disappears when the top and bottom face halves are spatially misaligned. Whether this is because the two halves no longer form a whole face (ie they form two segmented parts), or because of an increase in interfeatures distance in the misaligned condition (eg eyes-mouth distance) remains unclear. Here, thirty-four participants performed a delayed matching composite task in which the amount of spatial misalignment between face halves varied parametrically (from 8.33% of face width to 100%). The difference in performance between aligned and misaligned faces (ie the composite face effect) was already of full magnitude at the smallest level of misalignment. These results imply that a small spatial misalignment is sufficient to measure the composite face effect. From a theoretical standpoint, they indicate that it is the breaking of a whole configuration rather than the increase in relative distance between the face parts that explains the presence or absence of the composite face effect, clarifying an outstanding issue concerning the nature of holistic face perception.
Where Have Eye Been? Observers Can Recognise Their Own Fixations
Authors: Foulsham Tom , Kingstone Alan
Published: November 2013

We are often not explicitly aware of the location of our spatial attention, despite its influence on our perception and cognition. During a picture memory task, we asked whether people could later recognise their eye fixations in a two-alternative test. In three separate experiments, participants performed above chance when discriminating their own fixation patterns from random locations or locations fixated in a different image. Recognition was much poorer when the task was to spot your own versus someone else's fixations on the same stimulus, but performance remained better than chance. That we are sensitive to our own scan patterns has implications for perception, memory, and meta-cognition.
Visuospatial Attention and Motor Skills in Kung Fu Athletes
Authors: Muiños Mónica , Ballesteros Soledad
Published: November 2013

The present study compared the performance of a group of sixteen kung fu athletes with that of a control group of fourteen nonathletes on a speeded visuospatial task and a hand-tapping motor task. In the visuospatial task the results showed that athletes were faster than the control participants when stimuli were presented at the periphery of the visual field at a middle and high presentation speed with short interstimulus intervals. Athletes were also significantly faster than nonathlete participants when performing motor actions such as hand-tapping with their dominant hand but groups did not differ with the nondominant hand. These results support the view that athletes perform some speeded visuospatial and motor tasks faster than nonathletes under certain conditions. The findings suggest that, after several years of practice, kung fu athletes develop certain skills that allow them to perform motor speed maneuvers under time pressure conditions.
Mechanism for the catastrophe-promoting activity of the microtubule destabilizer Op18/stathmin
Authors: Gupta Kamlesh K. , Li Chunlei , Duan Aranda , Alberico Emily O. , Kim Oleg V. , Alber Mark S. , Goodson Holly V.
Published: November 2013

Significance

The microtubule (MT) cytoskeleton is a dynamic polymer network that plays a crucial role in cell function and disease. MT assembly and dynamics are precisely controlled; a key regulator is the MT destabilizer known as stathmin. Stathmin’s mechanism of action remains controversial: one well-supported model is that it reduces polymer indirectly by sequestering MT subunits; the alternative is that it acts directly on MTs by an as yet unknown mechanism. We provide a resolution to this debate by presenting experimental evidence that stathmin can act directly on MTs and does so by binding and destabilizing exposed protofilaments. Computer simulations performed in parallel suggest that both the direct and sequestering activities are likely to be significant in a cellular context.
Genome-wide analysis of histone marks identifying an epigenetic signature of promoters and enhancers underlying cardiac hypertrophy
Authors: Papait Roberto , Cattaneo Paola , Kunderfranco Paolo , Greco Carolina , Carullo Pierluigi , Guffanti Alessandro , Viganò Valentina , Stirparo Giuliano Giuseppe , Latronico Michael V. G. , Hasenfuss Gerd , Chen Ju , Condorelli Gianluigi
Published: November 2013

Significance

Cardiac failure is a leading cause of mortality worldwide and a major financial burden for healthcare systems. New tools for understanding cardiovascular disease and developing better therapeutic approaches are therefore needed. To this end, transcriptional regulation has been extensively studied in cardiac hypertrophy and failure, but there is still a lack of understanding of the epigenetic framework in which transcription factors act. Our report adds significant knowledge to the field because we demonstrate, in vivo, that a complex and specific epigenetic signature regulates gene expression by modulating promoters and enhancers, a large number of which have been described here. These findings advance our understanding of the mechanisms underlying this pathology.
Chordin forms a self-organizing morphogen gradient in the extracellular space between ectoderm and mesoderm in the
Xenopus
embryo
Authors: Plouhinec Jean-Louis , Zakin Lise , Moriyama Yuki , De Robertis Edward M.
Published: November 2013

Significance

Cell differentiation in the embryo is regulated by diffusible substances called “morphogens,” but these have never been directly visualized as endogenous components of the extracellular space. Chordin is an antagonist of the bone morphogenetic protein (BMP) pathway copiously secreted by a dorsal region of the
Xenopus
embryo called “Spemann’s organizer” that has potent tissue-inducing activity. We report that Chordin protein forms a dorsal-to-ventral gradient in the embryo. This gradient is located in a narrow space containing extracellular matrix (ECM) that separates the ectoderm from the endomesoderm, which seems to serve as a highway for the diffusion of Chordin–BMP complexes over very long distances (2 mm) in the embryo. All vertebrate embryos have a similar ECM between ectoderm and mesoderm during gastrulation.
Cross-modal resonances in creative multimodal metaphors
Authors: El Refaie Elisabeth
Published: November 2013

This article uses examples of multimodal metaphors from three different genres in order to develop a new understanding of the nature of creativity in metaphor. I argue that multimodality provides distinctive opportunities for metaphor creativity by exploiting the unique affordances of the different semiotic modes and the possibility of combining them in unexpected ways. Such innovation at the level of representation may encourage novel thought patterns, I suggest, even in such cases where the underlying metaphorical mappings are relatively conventional. The notion of “cross-modal resonances” is introduced to emphasize the role of unconscious, preverbal, intuitive understanding and the emotions in producing and interpreting creative multimodal metaphors.
Metaphor and symbol
Authors: Forceville Charles
Published: November 2013

The quickly growing discipline of multimodality has hitherto primarily found its inspirational models in semiotics and in Systemic Functional Linguistics. However, Cognitive Linguistics, and specifically its Conceptual Metaphor
Theory branch, has over the past years proved a store of knowledge and methods of analysis that can benefit the further advance of the young discipline. In this paper the metaphor searching for one’s identity is looking for a home in animation films is examined. It is shown that (a) analysing this metaphor presupposes understanding “home” as a symbol; (b) animation has medium-specific affordances to implement the metaphor; (c) the metaphor combines embodied and cultural dimensions.
Running‐induced patellofemoral pain fluctuates with changes in patella water content
Authors: Ho Kai‐Yu , Hu Houchun H. , Colletti Patrick M. , Powers Christopher M.
Published: November 2013

Although increased bone water content resulting from repetitive patellofemoral joint loading has been suggested to be a possible mechanism underlying patellofemoral pain (PFP), there is little data to support this mechanism. The purpose of the current study was to determine whether running results in increases in patella water content and pain and whether 48 hours of rest reduces patella water content and pain to pre‐running levels. Ten female runners with a diagnosis of PFP (mean age 25.1 years) participated. Patella water content was quantified using a chemical‐shift‐encoded water‐fat magnetic resonance imaging (MRI) protocol. The visual analog scale (VAS) was used to quantify subjects' pain levels. MRI and pain data were obtained prior to running, immediately following a 40‐minute running session, and 48 hours post‐running. Pain and patella water content were compared among the 3 time points using one‐way ANOVA's with repeated measures. Immediately post‐running, persons with PFP reported significant increases in pain and exhibited elevated patella water content. Pain and patella water content decreased to pre‐running levels following 48 hours of rest. Our findings suggest that transient changes in patella water content associated with running may, in part, contribute to patellofemoral symptoms.
Familistic welfare capitalism in crisis: social reproduction and anti-social policy in Greece
Authors: Papadopoulos Theodoros , Roumpakis Antonios
Published: November 2013

Familistic welfare capitalism is a model of national political economy prevalent in many regions in the world (Southern Europe, Latin America, and Asia), where the family plays a double role as the key provider of welfare and a key agent in the model's socio-economic and political reproduction. The article offers a new approach to the study this model by adopting an expanded concept of social reproduction to capture its historical evolution, using Greece as a case study. Our empirical analysis of austerity measures on employment and pensions demonstrates, how, in the Greek case, a crisis of social reproduction of the traditional form of familistic welfare capitalism was already underway prior to the well-known sovereign-debt crisis. And further we show how the adoption of austerity measures and pro-market reforms is deepening this crisis by severely undermining the key pillars of familial welfare security while rapidly transforming the model into a political economy of generalised insecurity.
Comparative transcriptomics reveals RhoE as a novel regulator of actin dynamics in bone-resorbing osteoclasts
Authors: Georgess Dan , Mazzorana Marlène , Terrado José , Delprat Christine , Chamot Christophe , Guasch Rosa M. , Pérez-Roger Ignacio , Jurdic Pierre , Machuca-Gayet Irma
Published: November 2013

The function of osteoclasts (OCs), multinucleated giant cells (MGCs) of the monocytic lineage, is bone resorption. To resorb bone, OCs form podosomes. These are actin-rich adhesive structures that pattern into rings that drive OC migration and into “sealing-zones” (SZs) that confine the resorption lacuna. Although changes in actin dynamics during podosome patterning have been documented, the mechanisms that regulate these changes are largely unknown. From human monocytic precursors, we differentiated MGCs that express OC degradation enzymes but are unable to resorb the mineral matrix. We demonstrated that, despite exhibiting bona fide podosomes, these cells presented dysfunctional SZs. We then performed two-step differential transcriptomic profiling of bone-resorbing OCs versus nonresorbing MGCs to generate a list of genes implicated in bone resorption. From this list of candidate genes, we investigated the role of Rho/Rnd3. Using primary RhoE-deficient OCs, we demonstrated that RhoE is indispensable for OC migration and bone resorption by maintaining fast actin turnover in podosomes. We further showed that RhoE activates podosome component cofilin by inhibiting its Rock-mediated phosphorylation. We conclude that the RhoE-Rock-cofilin pathway, by promoting podosome dynamics and patterning, is central for OC migration, SZ formation, and, ultimately, bone resorption.
Low-affinity IgM antibodies lacking somatic hypermutations are produced in the secondary response of C57BL/6 mice to (4-hydroxy-3-nitrophenyl)acetyl hapten
Authors: Murakami Akikazu , Moriyama Hayato , Osako-Kabasawa Mina , Endo Kanako , Nishimura Miyuki , Udaka Keiko , Muramatsu Masamichi , Honjo Tasuku , Azuma Takachika , Shimizu Takeyuki
Published: November 2013

Class-switched memory B cells, which are generated through the processes of somatic hypermutation (SHM) and affinity-based selection in germinal centers, contribute to the production of affinity-matured IgG antibodies in the secondary immune response. However, changes in the affinity of IgM antibodies during the immune response have not yet been studied, although IgM+ memory B cells have been shown to be generated. In order to understand the relationship between IgM affinity and the recall immune response, we prepared hybridomas producing anti-(4-hydroxy-3-nitrophenyl)acetyl (NP) IgM antibodies from C57BL/6 mice and from activation-induced cytidine deaminase (AID)-deficient mice. Binding analysis by ELISA showed that mAbs obtained from the secondary immune response contained IgM mAbs with affinity lower than the affinity of mAbs obtained from the primary response. By analyzing sequences of the IgM genes of hybridomas and plasma cells, we found many unmutated VH genes. VH genes that had neither tyrosine nor glycine at position 95 were frequent. The repertoire change may correlate with the lower affinity of IgM antibodies in the secondary response. The sequence and affinity changes in IgM antibodies were shown to be independent of SHM by analyzing hybridomas from AID-deficient mice. A functional assay revealed a reciprocal relationship between affinity and complement-dependent hemolytic activity toward NP-conjugated sheep RBCs; IgM antibodies with lower affinities had higher hemolytic activity. These findings indicate that lower affinity IgM antibodies with enhanced complement activation function are produced in the secondary immune response.