bluuebunny/crossref_metadata_2025 huggingface dataset:
Translational Insights into Traumatic Brain Injury Occurring during Dabigatran or Warfarin Anticoagulation
Authors: Schaefer Jan Hendrik , Leung Wendy , Wu Limin , Van Cott Elizabeth M , Lok Josephine , Whalen Michael , van Leyen Klaus , Lauer Arne , van Ryn Joanne , Lo Eng H , Foerch Christian
Published: February 2014

To date, only limited data are available on the effects of pretreatment with novel oral anticoagulants in the event of traumatic brain injury (TBI). We determined intracerebral hemorrhage volume and functional outcome in a standardized TBI model in mice treated with warfarin or dabigatran. Additionally, we investigated whether excess concentrations of dabigatran could increase bleeding and whether this was preventable by using prothrombin complex concentrate (PCC). C57 mice were treated orally with warfarin or dabigatran; sham-treated mice served as controls. Effective anticoagulation was verified by measurement of international normalized ratio and diluted thrombin time, and TBI was induced by controlled cortical impact (CCI). Twenty-four hours after CCI, intracerebral hemorrhage volume was larger in warfarin-pretreated mice than in controls (10.1 ± 4.9 vs 4.1 ± 1.7 μL; analysis of variance post hoc P = 0.001), but no difference was found between controls and dabigatran-pretreated mice (5.3 ± 1.5 μL). PCC applied 30 minutes after CCI did not reliably reduce intracerebral hemorrhage induced by excess dabigatran concentration compared with saline (10.4 ± 11.2 vs 8.7 ± 7.1 μL). Our data suggest pathophysiological differences in TBI occurring during warfarin and dabigatran anticoagulation. The reduced hemorrhage formation under dabigatran therapy could present a safety advantage compared with warfarin. An excess dabigatran concentration, however, can increase hemorrhage.
Synthesis of pharmaceutically relevant 17-α-amino steroids using an ω-transaminase
Authors: Richter Nina , Simon Robert C. , Kroutil Wolfgang , Ward John M. , Hailes Helen C.
Published: February 2014

An efficient and stereoselective biocatalytic route for the synthesis of 17α-amino steroids has been developed.
Self-assembly of sterically-rigidified 3-connecting benzenetribenzoic acid into (6,3) and (3,3) nets and stabilization of water channel in the crystal lattice
Authors: Bajpai Alankriti , Venugopalan Paloth , Moorthy Jarugu Narasimha
Published: February 2014

A rigid 3-connecting triacid MeBTB was designed and synthesized in the quest of guest inclusion in the pores of honeycomb network structures generated based on the acid dimer-mediated self-assembly.
On the gas-phase reaction between SO2 and O2−(H2O)0–3 clusters – an ab initio study
Authors: Tsona Narcisse T. , Bork Nicolai , Vehkamäki Hanna
Published: February 2014

An ab initio study on the outcome of a collision between SO2 and the O2−(H2O)0–2 anion.
Exploring the structure–aromaticity relationship in Hückel and Möbius N-fused pentaphyrins using DFT
Authors: Alonso M. , Geerlings P. , . De Proft F
Published: February 2014

Fine-tuning of the molecular topology and macrocyclic aromaticity of N-fused pentaphyrins by changing the number of π electrons and meso-substituents.
Stainless steel foam increases the current produced by microbial bioanodes in bioelectrochemical systems
Authors: Ketep Stéphanie F. , Bergel Alain , Calmet Amandine , Erable Benjamin
Published: February 2014

Stainless steel is gaining increasing interest as an anodic material in bioelectrochemical systems and beginning to challenge the more conventional carbon-based materials.
Interaction of the NAMI-A complex with nitric oxide under physiological conditions
Authors: Oszajca Maria , Kuliś Ewa , Stochel Grażyna , Brindell Małgorzata
Published: February 2014

The NAMI-A ([ImH][RuCl4(Im)(DMSO)], Im – imidazole, DMSO – dimethyl sulfoxide) interact with nitric oxide (NO) under physiological-like conditions, however it is rather kinetically sluggish NO scavenger.
Solution reduction synthesis of amine terminated carbon quantum dots
Authors: Linehan Keith , Doyle Hugh
Published: February 2014

Highly luminescent water soluble carbon quantum dots (CQDs) with narrow size distributions have been prepared via a simple room temperature, solution-phase synthesis. The CQDs, stabilised by covalently bound allylamine ligands to minimise surface oxidation, exhibit an excitation wavelength dependent blue luminescence with a quantum yield of 25%.
Mechanistic insights into the malonoyl peroxide syn-dihydroxylation of alkenes
Authors: Rawling Michael J. , Rowley Julian H. , Campbell Matthew , Kennedy Alan R. , Parkinson John A. , Tomkinson Nicholas C. O.
Published: February 2014

A detailed mechanistic understanding of the malonoyl peroxide mediated dihydroxylation of alkenes is presented.
ScGaN and ScAlN: emerging nitride materials
Authors: Moram M. A. , Zhang S.
Published: February 2014

ScAlN and ScGaN alloys are wide band-gap semiconductors which can greatly expand the options for band gap and polarisation engineering required for efficient III-nitride optoelectronic devices, high-electron mobility transistors and energy-harvesting devices.
Vapor-phase deposition of polymers as a simple and versatile technique to generate paper-based microfluidic platforms for bioassay applications
Authors: Demirel Gokhan , Babur Esra
Published: February 2014

A simple yet versatile approach has been demonstrated for the fabrication of paper-based microfluidic platforms based on a vapor-phase polymerization technique.
Synthesis and anion binding studies of o-phenylenevinylene-bridged tetrapyrrolic macrocycle as an expanded analogue of calix[4]pyrrole
Authors: Ghosh Sudip Kumar , Ishida Masatoshi , Li Jiazhu , Cha Won-Young , Lynch Vincent M. , Kim Dongho , Sessler Jonathan L.
Published: February 2014

An expanded analogue of calix[4]pyrrole with a flexible scaffold has been prepared; it acts as an effective anion receptor in organic media.
Computational screening of structural and compositional factors for electrically conductive coordination polymers
Authors: Tiana Davide , Hendon Christopher H. , Walsh Aron , Vaid Thomas P.
Published: February 2014

We test a range of building blocks and connectivity for the construction of electroactive metal–organic frameworks.
Catalytic kinetic resolution of a dynamic racemate: highly stereoselective β-lactone formation by N-heterocyclic carbene catalysis
Authors: Johnston Ryne C. , Cohen Daniel T. , Eichman Chad C. , Scheidt Karl A. , Ha-Yeon Cheong Paul
Published: February 2014

This NHC-catalyzed β-lactone formation reaction displays a novel mechanism and belongs to a rare class of dynamic kinetic resolutions.
Fabrication of ZnO nanoplates for visible light-induced imaging of living cells
Authors: Lee Jooran , Choi Joon Sig , Yoon Minjoong
Published: February 2014

APTES-modified ZnO nanoplates (NPls) showed excellent permeability into HeLa cells with negligible cytotoxicity, exhibiting strong red fluorescence emission (∼650 nm) under visible light excitation at 405 nm. Therefore, the synthesized ZnO NPls would be useful for highly resolved cellular imaging by avoiding the overlap with the cellular intrinsic green emission.
Traumatic Brain Injury and Aging
Authors: Batson-Magnuson LuAnn
Published: February 2014

While often occurring in younger people, traumatic brain injury (TBI) can occur at any age, and there may be specific concerns with this diagnosis in older people. This article will discuss the aging of individuals who have previously experienced TBI, and it will also discuss the particular concerns of older people suffering a new onset TBI.
Reflections on Aging: Normal Developmental Process or Disease?
Authors: Schreck Janet Simon
Published: February 2014

The process of aging is unavoidable and unrelenting in human beings. Is aging a normal stage of human development or a disease that can be treated, delayed, or perhaps even cured? This article explores the aging process from multiple perspectives and discusses the potential impacts of those varying perspectives on determination of health care policy and allocation of research dollars.
Runway incursion prevention method based on a discrete object sensing event‐driven model
Authors: Xin‐min Tang , Jian Xing , Song‐chen Han
Published: February 2014

A runway incursion prevention system for high density airports based on an event‐driven sensor network is presented, in which non‐cooperative active detection sensors, such as microwave or infrared sensors installed beside the critical points of runways and taxiways other than SMR, ADS‐B, or MLAT to detect and locate aircraft or vehicle continuously, and the discrete airdrome surface traffic situation can be reconstructed based on the fusion of object sensing events detected by a sensor network and the landing and taking off events reported by pilots. Thus, an airdrome surface operation model based on Petri Nets is proposed based on runway operation rules in the present study. After defining the runway prevention control regulations, runway incursion detection and prevention was transformed into a state forbidden problem. A logical controller that satisfied a strong regulatory condition design method was developed for uncontrollable events in the airdrome surface operation model. The logical controller we proposed is centralised and maximally permissive, and the runway incursion prevention control actions, such as airfield lighting system, can be adopted to execute the discrete control policies generated by logical controller automatically. The illustrated case demonstrated that a controller designed with stop‐bar lights or center‐line guidance lights could prevent runway incursions in an efficient manner, while its time complexity depended only on the sensor network configurations rather than the number of objects, which is more suitable for high density airports. In general, the combination of active event‐driven sensor and discrete event controller is a RIPS solution.
Numerical simulation of a mode‐locked quantum dot external cavity laser
Authors: Dogru Nuran , Adams Mike J.
Published: February 2014

The mode‐locked characteristics of a quantum dot hybrid soliton pulse source (QD‐HSPS) utilising a linearly chirped fibre Bragg grating (FBG) are investigated using the time‐domain solution of coupled wave equations and rate equations. The effect of carrier dynamics on the output pulse of the QD‐HSPS is also described. The numerical results indicate that the spontaneous coupling factor, carrier recombination time in QD and the length of the laser strongly affect the system operation, whereas there is no significant effect of carrier recombination in the wetting layer or of the carrier emission from the QD to the wetting layer or of the relaxation time from the wetting layer to the QD. Furthermore, it is also shown that by using the optimum parameters a QD‐HSPS utilising a linearly chirped Gaussian‐apodised FBG produces considerably shorter pulses when compared with a multi‐quantum‐well HSPS (MQW‐HSPS) utilising linearly and non‐linearly chirped gratings, along with an increase in the mode‐locking frequency range.
Efficient terahertz devices based on III–V semiconductor photoconductors
Authors: Kostakis Ioannis , Saeedkia Daryoosh , Missous Mohamed
Published: February 2014

A series of planar aperture and dipole antenna structures fabricated on low temperature grown GaAs and InP‐based photoconductors have been evaluated as terahertz (THz) emitters and detectors in a time‐domain spectroscopy system under pulsed excitation. The combination of large aperture antennas as emitters and short dipole antennas as detectors results in efficient THz devices operating at 800 nm, 1 μm and 1.55 μm excitation wavelengths. The system responses of these materials are among the best ever reported and allow high‐quality measurements to be made. Finally, characterisation of a structure able to be biased vertically and its evaluation as THz emitter is reported for the first time. The THz response of this material with a strong THz signal at low‐voltage bias makes the development of battery‐operated THz devices possible.
Electrically pumped continuous‐wave 1.3‐µm InAs/GaAs quantum dot lasers monolithically grown on Si substrates
Authors: Wu Jiang , Lee Andrew , Jiang Qi , Tang Mingchu , Seeds Alwyn J. , Liu Huiyun
Published: February 2014

Continuous‐wave (CW) operation of InAs/GaAs quantum dot (QD) lasers monolithically grown on Si substrates by molecular beam epitaxy is presented. The peak lasing wavelength of 1278 nm is accompanied by a low threshold current density of 458 A/cm2 at 8°C using a GaAs buffer layer directly grown on the Si substrates. The improvement in laser performance is due to improved crystal quality of the GaAs buffer layer. The demonstration of a CW QD laser also benefits from using top–top contacts, which route the current through the laser active layer to avoid the high‐density defects near the Si/GaAs interface. These results demonstrate the growing potential of the monolithically integrated III–V QD lasers on the Si substrates.
Vortex magnetic structure in circularly magnetized microwires as deduced from magneto-optical Kerr measurements
Authors: Ivanov Yu. P. , del Real R. P. , Chubykalo-Fesenko O. , Vázquez M.
Published: February 2014

The magneto-optic Kerr effect has been employed to determine the magnetization process and estimate the domain structure of microwires with circular magnetic anisotropy. The diameter of microwires was 8 μm, and pieces 2 cm long were selected for measurements. The analysis of the local surface longitudinal and transverse hysteresis loops has allowed us to deduce a vortex magnetic structure with axial core and circular external shell. Moreover, a bamboo-like surface domain structure is confirmed with wave length of around 10 to 15 μm and alternating chirality in adjacent circular domains. The width of the domain wall is estimated to be less than 3 μm. Finally, closure domain structures with significant helical magnetization component are observed extending up to around 1000 μm from the end of the microwire.
Uncertainty in least-squares fits to the thermal noise spectra of nanomechanical resonators with applications to the atomic force microscope
Authors: Sader John E. , Yousefi Morteza , Friend James R.
Published: February 2014

Thermal noise spectra of nanomechanical resonators are used widely to characterize their physical properties. These spectra typically exhibit a Lorentzian response, with additional white noise due to extraneous processes. Least-squares fits of these measurements enable extraction of key parameters of the resonator, including its resonant frequency, quality factor, and stiffness. Here, we present general formulas for the uncertainties in these fit parameters due to sampling noise inherent in all thermal noise spectra. Good agreement with Monte Carlo simulation of synthetic data and measurements of an Atomic Force Microscope (AFM) cantilever is demonstrated. These formulas enable robust interpretation of thermal noise spectra measurements commonly performed in the AFM and adaptive control of fitting procedures with specified tolerances.
Fourier transform infrared isotopic study of SiC5: Identification of the ν4(σ) mode
Authors: Lê T. H. , Rittby C. M. L. , Graham W. R. M.
Published: February 2014

SiC5 in its 3Σ ground state has been produced by trapping the products from the laser evaporation of a sintered silicon-carbon rod in solid Ar. For the first time a vibrational fundamental has been measured, the ν4(σ) asymmetric stretch at 936.9 ± 0.2 cm−1. Comparison of observed 13C and 29,30Si isotopic shifts with the predictions of DFT-B3LYP/cc-pVDZ calculations confirms the identification.
Stratified spin-up in a sliced, square cylinder
Authors: Munro R. J. , Foster M. R.
Published: February 2014

We previously reported experimental and theoretical results on the linear spin-up of a linearly stratified, rotating fluid in a uniform-depth square cylinder [M. R. Foster and R. J. Munro, “The linear spin-up of a stratified, rotating fluid in a square cylinder,” J. Fluid Mech. 712, 7–40 (2012)]. Here we extend that analysis to a “sliced” square cylinder, which has a base-plane inclined at a shallow angle α. Asymptotic results are derived that show the spin-up phase is achieved by a combination of the Ekman-layer eruptions (from the perimeter region of the cylinder's lid and base) and cross-slope-propagating stratified Rossby waves. The final, steady state limit for this spin-up phase is identical to that found previously for the uniform depth cylinder, but is reached somewhat more rapidly on a time scale of order E−1/2Ω−1/log (α/E1/2) (compared to E−1/2Ω−1 for the uniform-depth cylinder), where Ω is the rotation rate and E the Ekman number. Experiments were performed for Burger numbers, S, between 0.4 and 16, and showed that for \documentclass[12pt]{minimal}\begin{document}$S\gtrsim \mathcal {O}\left(1\right)$\end{document}S≳O1, the Rossby modes are severely damped, and it is only at small S, and during the early stages, that the presence of these wave modes was evident. These observations are supported by the theory, which shows the damping factors increase with S and are numerically large for \documentclass[12pt]{minimal}\begin{document}$S\gtrsim \mathcal {O}\left(1\right)$\end{document}S≳O1.
Near-resonant rotational energy transfer in HCl–H2 inelastic collisions
Authors: Lanza Mathieu , Kalugina Yulia , Wiesenfeld Laurent , Lique François
Published: February 2014

We present a new four-dimensional (4D) potential energy surface for the HCl–H2 van der Waals system. Both molecules were treated as rigid rotors. Potential energy surface was obtained from electronic structure calculations using a coupled cluster with single, double, and perturbative triple excitations method. The four atoms were described using the augmented correlation-consistent quadruple zeta basis set and bond functions were placed at mid-distance between the HCl and H2 centers of mass for a better description of the van der Waals interaction. The global minimum is characterized by the well depth of 213.38 cm−1 corresponding to the T-shape structure with H2 molecule on the H side of the HCl molecule. The dissociation energies D0 are 34.7 cm−1 and 42.3 cm−1 for the complex with para- and ortho-H2, respectively. These theoretical results obtained using our new PES are in good agreement with experimental values [D. T. Anderson, M. Schuder, and D. J. Nesbitt, Chem. Phys. 239, 253 (1998)]. Close coupling calculations of the inelastic integral rotational cross sections of HCl in collisions with para-H2 and ortho-H2 were performed at low and intermediate collisional energies. Significant differences exist between para- and ortho-H2 results. The strongest collision-induced rotational HCl transitions are the transitions with Δj = 1 for collisions with both para-H2 and ortho-H2. Rotational relaxation of HCl in collision with para-H2 in the rotationally excited states j = 2 is dominated by near-resonant energy transfer.
Multichannel microwave interferometer with an antenna switching system for electron density measurement in a laboratory plasma experiment
Authors: Kawamori Eiichirou , Lin Yu-Hsiang , Mase Atsushi , Nishida Yasushi , Cheng C. Z.
Published: February 2014

This study presents a simple and powerful technique for multichannel measurements of the density profile in laboratory plasmas by microwave interferometry. This technique uses electromechanical microwave switches to temporally switch the connection between multiple receiver antennas and one phase-detection circuit. Using this method, the phase information detected at different positions is rearranged into a time series that can be acquired from a minimum number of data acquisition channels (e.g., two channels in the case of quadrature detection). Our successfully developed multichannel microwave interferometer that uses the antenna switching method was applied to measure the radial electron density profiles in a magnetized plasma experiment. The advantage of the proposed method is its compactness and scalability to multidimensional measurement systems at low cost.
The evaluation of phasemeter prototype performance for the space gravitational waves detection
Authors: Liu He-Shan , Dong Yu-Hui , Li Yu-Qiong , Luo Zi-Ren , Jin Gang
Published: February 2014

Heterodyne laser interferometry is considered as the most promising readout scheme for future space gravitational wave detection missions, in which the gravitational wave signals disguise as small phase variances within the heterodyne beat note. This makes the phasemeter, which extracts the phase information from the beat note, the key device to this system. In this paper, a prototype of phasemeter based on digital phase-locked loop technology is developed, and the major noise sources which may contribute to the noise spectra density are analyzed in detail. Two experiments are also carried out to evaluate the performance of the phasemeter prototype. The results show that the sensitivity is achieved 2π μrad/√Hz in the frequency range of 0.04 Hz-10 Hz. Due to the effect of thermal drift, the noise obviously increases with the frequencies down to 0.1 mHz.
Coherent superposition of M-states in a single rovibrational level of H2 by Stark-induced adiabatic Raman passage
Authors: Mukherjee Nandini , Dong Wenrui , Zare Richard N.
Published: February 2014

We prepare an ensemble of isolated rovibrationally excited (v = 1, J = 2) H2 molecules in a phase-locked superposition of magnetic sublevels M using Stark-induced adiabatic Raman passage with linearly polarized single-mode pump (at 532 nm, ∼6 ns pulse duration, 200 mJ/pulse) and Stokes (699 nm, ∼4 ns pulse duration, 20 mJ/pulse) laser excitation. A biaxial superposition state, given by $| {\psi (t)}\rangle = 1/\sqrt {(2)} [ | {v=1,J = 2,M = - 2} \rangle - | {v=1,J = 2,M = + 2} \rangle ]$|ψ(t)⟩=1/(2)[|v=1,J=2,M=−2⟩−|v=1,J=2,M=+2⟩], is prepared with linearly but cross-polarized pump and Stokes laser pulses copropagating along the quantization z-axis. The degree of phase coherence is measured by using the O(2) line of the H2 E,F-X (0,1) band via 2 + 1 resonance enhanced multiphoton ionization (REMPI) at 210.8 nm by recording interference fringes in the REMPI signal in a time-of-flight mass spectrometer as the direction of the UV laser polarization is rotated using a half-wave plate. Nearly 60% population transfer from H2 (v = 0, J = 0) ground state to the superposition state in H2 (v = 1, J = 2) is measured from the depletion of the Q(0) line of the E,F-X (0,0) band as the Stokes frequency is tuned across the (v = 0, J = 0) → (v = 1, J = 2) Raman resonance.
Effects of atmospheric parameters on radon measurements using alpha-track detectors
Authors: Zhao C. , Zhuo W. , Fan D. , Yi Y. , Chen B.
Published: February 2014

The calibration factors of alpha-track radon detectors (ATDs) are essential for accurate determination of indoor radon concentrations. In this paper, the effects of atmospheric parameters on the calibration factors were theoretically studied and partially testified. Based on the atmospheric thermodynamics theory and detection characteristics of the allyl diglycol carbonate (CR-39), the calibration factors for 5 types of ATDs were calculated through Monte Carlo simulations under different atmospheric conditions. Simulation results showed that the calibration factor increased by up to 31% for the ATDs with a decrease of air pressure by 35.5 kPa (equivalent to an altitude increase of 3500 m), and it also increased by up to 12% with a temperature increase from 5 °C to 35 °C, but it was hardly affected by the relative humidity unless the water-vapor condensation occurs inside the detectors. Furthermore, it was also found that the effects on calibration factors also depended on the dimensions of ATDs. It indicated that variations of the calibration factor with air pressure and temperature should be considered for an accurate radon measurement with a large dimensional ATD, and water-vapor condensation inside the detector should be avoided in field measurements.
Photoluminescence from InGaAs/GaAs quantum well regrown on a buried patterned oxidized AlAs layer
Authors: Chouchane F. , Makhloufi H. , Calvez S. , Fontaine C. , Almuneau G.
Published: February 2014

We present a quasi-planar technological approach for forming a flexible and versatile confinement scheme based on oxidation of AlGaAs buried layers combined to an epitaxial regrowth. This method improves the electrical and optical confinements compared to the lateral oxidation since it allows to define confinement areas from a planar surface. This technique is suitable for the realization of advanced integrated photonic components arrays with close device-to-device spacing such as two-dimensional arrays of vertical-cavity surface-emitting lasers. Our results prove that the oxidation and epitaxial regrowth can be sequenced in a process flow, leading to viable confinement while preserving good radiative properties.
Thickness dependence of spin torque ferromagnetic resonance in Co75Fe25/Pt bilayer films
Authors: Ganguly A. , Kondou K. , Sukegawa H. , Mitani S. , Kasai S. , Niimi Y. , Otani Y. , Barman A.
Published: February 2014

The spin Hall angle of Pt in Co75Fe25/Pt bilayer films was experimentally investigated by means of the spin-torque ferromagnetic resonance and the modulation of damping measurements. By comparing the present results with the Ni80Fe20/Pt system, we found that the ferromagnetic layer underneath the Pt one greatly affects the estimation of the spin Hall angle. We also discuss the spin diffusion length of Pt and the ferromagnetic thickness dependence of the Gilbert damping coefficient.
Underwater acoustic omnidirectional absorber
Authors: Naify Christina J. , Martin Theodore P. , Layman Christopher N. , Nicholas Michael , Thangawng Abel L. , Calvo David C. , Orris Gregory J.
Published: February 2014

Gradient index media, which are designed by varying local element properties in given geometry, have been utilized to manipulate acoustic waves for a variety of devices. This study presents a cylindrical, two-dimensional acoustic “black hole” design that functions as an omnidirectional absorber for underwater applications. The design features a metamaterial shell that focuses acoustic energy into the shell's core. Multiple scattering theory was used to design layers of rubber cylinders with varying filling fractions to produce a linearly graded sound speed profile through the structure. Measured pressure intensity agreed with predicted results over a range of frequencies within the homogenization limit.
Thermal conductivity control by oxygen defect concentration modification in reducible oxides: The case of Pr0.1Ce0.9O2−δ thin films
Authors: Luckyanova Maria N. , Chen Di , Ma Wen , Tuller Harry L. , Chen Gang , Yildiz Bilge
Published: February 2014

We demonstrate the impact on thermal conductivity of varying the concentration of oxygen vacancies and reduced cations in Pr0.1Ce0.9O2−δ thin films prepared by pulsed laser deposition. The oxygen vacancy concentration is controlled by varying the oxygen partial pressure between 1 × 10−4 and 1 atm at 650  °C. Corresponding changes in the oxygen non-stoichiometry (δ) are monitored by detecting the lattice parameters of the films with high-resolution X-ray diffraction, while the thermal properties are characterized by time-domain thermoreflectance measurements. The films are shown to exhibit a variation in oxygen vacancy content, and in the Pr3+/Pr4+ ratio, corresponding to changes in δ from 0.0027 to 0.0364, leading to a reduction in the thermal conductivity from k = 6.62 ± 0.61 to 3.82 ± 0.51 W/m-K, respectively. These values agree well with those predicted by the Callaway and von Baeyer model for thermal conductivity in the presence of point imperfections. These results demonstrate the capability of controlling thermal conductivity via control of anion and cation defect concentrations in a given reducible oxide.
An in-depth noise model for giant magnetoresistance current sensors for circuit design and complementary metal–oxide–semiconductor integration
Authors: Roldán A. , Roldán J. B. , Reig C. , Cardoso S. , Cardoso F. , Ferreira R. , Freitas P. P.
Published: February 2014

Full instrumentation bridges based on spin valve of giant magnetoresistance and magnetic tunnel junction devices have been microfabricated and experimentally characterized from the DC and noise viewpoint. A more realistic model of these devices was obtained in this work, an electrical and thermal model previously developed have been improved in such a way that noise effects are also included. We have implemented the model in a circuit simulator and reproduced the experimental measurements accurately. This provides a more realistic and complete tool for circuit design where magnetoresistive elements are combined with well-known complementary metal–oxide–semiconductor modules.
Parameter sensitivity analysis of nonlinear piezoelectric probe in tapping mode atomic force microscopy for measurement improvement
Authors: McCarty Rachael , Nima Mahmoodi S.
Published: February 2014

The equations of motion for a piezoelectric microcantilever are derived for a nonlinear contact force. The analytical expressions for natural frequencies and mode shapes are obtained. Then, the method of multiple scales is used to analyze the analytical frequency response of the piezoelectric probe. The effects of nonlinear excitation force on the microcantilever beam's frequency and amplitude are analytically studied. The results show a frequency shift in the response resulting from the force nonlinearities. This frequency shift during contact mode is an important consideration in the modeling of AFM mechanics for generation of more accurate imaging. Also, a sensitivity analysis of the system parameters on the nonlinearity effect is performed. The results of a sensitivity analysis show that it is possible to choose parameters such that the frequency shift minimizes. Certain parameters such as tip radius, microcantilever beam dimensions, and modulus of elasticity have more influence on the nonlinearity of the system than other parameters. By changing only three parameters—tip radius, thickness, and modulus of elasticity of the microbeam—a more than 70% reduction in nonlinearity effect was achieved.
Broadband subwavelength imaging using non-resonant metamaterials
Authors: Zheng Bin , Zhang Runren , Zhou Min , Zhang Weibin , Lin Shisheng , Ni Zhenhua , Wang Huaping , Yu Faxin , Chen Hongsheng
Published: February 2014

Previous subwavelength imaging using hyperlens is based on negative constitutive parameters that are realized by strongly dispersive materials and work only in a narrow frequency band. Here, we demonstrated that subwavelength imaging can be achieved in a broad frequency band using non-resonant magnetic metamaterials. The metamaterial shows an elliptical dispersion relation and can be fabricated by metallic closed-rings with a broadband magnetic response. With this elliptically dispersive material, most of the evanescent waves with high-k modes can be converted to propagating modes and the subwavelength information is reconstructed. Both simulation and experiment results show that this kind of metalens can achieve a broadband subwavelength imaging effect.
Strong Meissner screening change in superconducting radio frequency cavities due to mild baking
Authors: Romanenko A. , Grassellino A. , Barkov F. , Suter A. , Salman Z. , Prokscha T.
Published: February 2014

We investigate “hot” regions with anomalous high field dissipation in bulk niobium superconducting radio frequency cavities for particle accelerators by using low energy muon spin rotation (LE-μSR) on corresponding cavity cutouts. We demonstrate that superconducting properties at the hot region are well described by the non-local Pippard/BCS model for niobium in the clean limit with a London penetration depth λL=23±2 nm. In contrast, a cutout sample from the 120 ∘C baked cavity shows a much larger λ>100 nm and a depth dependent mean free path, likely due to gradient in vacancy concentration. We suggest that these vacancies can efficiently trap hydrogen and hence prevent the formation of hydrides responsible for rf losses in hot regions.
Analytical and experimental evaluation of energy storage using work of buoyancy force
Authors: Hai Alami Abdul
Published: February 2014

This paper presents theoretical formulation of, and experiments on a method of energy storage using the work of buoyancy force. The experiments proved that the energy storage using buoyancy force is an effective approach, as the experimental efficiency was found to exceed the theoretical estimation due to material properties of the buoys. The storage of mechanical energy without subsequent conversion into electrical energy has many advantages, including more compact storage setups, higher energy density retrieval, and higher efficiencies. For the current system, the efficiency of energy storage exceeds 37%. This value corresponds to earlier work by the author conducted for a single buoy, extending the prospects and applications of this approach to a better position in non-conventional energy storage applications.
Electron theory of perpendicular magnetic anisotropy of Co-ferrite thin films
Authors: Inoue Jun-ichiro , Niizeki Tomohiko , Yanagihara Hideto , Itoh Hiroyoshi , Kita Eiji
Published: February 2014

We develop an electron theory for the t2g electrons of Co2+ ions to clarify the perpendicular magnetic anisotropy (PMA) mechanism of Co-ferrite thin films by considering the spin-orbit interaction (SOI) and crystal-field (CF) potentials induced by the local symmetry around the Co ions and the global tetragonal symmetry of the film. Uniaxial and in-plane MA constants Ku and K1 at 0 K, respectively, are calculated for various values of SOI and CF. We show that reasonable parameter values explain the observed PMA and that the orbital moment for the in-plane magnetization reduces to nearly half of that of the out-of-plane magnetization.
Infrared transparent frequency selective surface based on metallic meshes
Authors: Yu Miao , Xu Nianxi , Liu Hai , Gao Jinsong
Published: February 2014

This paper presents an infrared transparent frequency selective surface (ITFSS) based on metallic meshes. In this ITFSS structure, periodic cross-slot units are integrated on square metallic meshes empowered by coating and UV-lithography. A matching condition is proposed to avoid the distortion of units. Experimental results show that this ITFSS possesses a good transmittance of 80% in the infrared band of 3–5 μm, and also a stable band-pass behavior at the resonance frequency of 36.4 GHz with transmittance of −0.56 dB. Theoretical simulations about the ITFSS diffractive characteristics and frequency responses are also investigated. The novel ITFSS will attract renewed interest and be exploited for applications in various fields.
Ultralow-threshold laser and blue shift cooperative luminescence in a Yb3+ doped silica microsphere
Authors: Huang Yantang , Huang Yu , Zhang Peijin , Guo Changlei
Published: February 2014

An experimental investigation on ultralow threshold laser and blue shift cooperative luminescence (CL) in a Yb3+ doped silica microsphere (YDSM) with continuous-wave 976 nm laser diode pumping is reported. The experimental results show that the YDSM emits laser oscillation with ultralow threshold of 2.62 μW, and the laser spectrum is modulated by the microsphere morphology characteristics. In addition, blue emission of YDSM is also observed with the increase of pump power, which is supposed to be generated by CL of excited Yb ion-pairs with the absorption of 976 nm photons and Si-O vibration phonons, and the process is explained with an energy level diagram. This property of the blue shift CL with phonons absorption in the Yb3+doped microcavity makes it attractive for the application of laser cooling based on anti-Stokes fluorescence emission, if the Yb3+doped microcavity made from with low phonon energy host materials.
Archaeological data provide alternative hypotheses on Pacific herring (Clupea pallasii) distribution, abundance, and variability
Authors: McKechnie Iain , Lepofsky Dana , Moss Madonna L. , Butler Virginia L. , Orchard Trevor J. , Coupland Gary , Foster Fredrick , Caldwell Megan , Lertzman Ken
Published: February 2014

Significance

Over the last century, Pacific herring, a forage fish of tremendous cultural, economic, and ecological importance, has declined in abundance over much of its range. We synthesize archaeological fisheries data spanning the past 10,000 y from Puget Sound in Washington to southeast Alaska to extend the ecological baseline for herring and contextualize the dynamics of modern industrial fisheries. While modern herring populations can be erratic and exhibit catastrophic declines, the archaeological record indicates a pattern of consistent abundance, providing an example of long-term sustainability and resilience in a fishery known for its modern variability. The most parsimonious explanation for the discrepancy between herring abundance in the ancient and more recent past is industrial harvesting over the last century.
Synergies between climate and management for Atlantic cod fisheries at high latitudes
Authors: Kjesbu Olav Sigurd , Bogstad Bjarte , Devine Jennifer A. , Gjøsæter Harald , Howell Daniel , Ingvaldsen Randi B. , Nash Richard D. M. , Skjæraasen Jon Egil
Published: February 2014

Significance

Currently many exploited fish populations, including many of the Atlantic cod stocks, are at historically low levels with widespread concern about whether contemporary management is capable of facilitating population recovery. In contrast, the spawning stock biomass of Barents Sea cod is now at an historic high. Here we demonstrate that successful management actions interacting synergistically with prevailing climate caused this increase. Warming of water masses in the Barents Sea over the last decade positively reinforced management actions. A unique and possibly generic mechanism of climate affecting marine animals at high latitudes, especially when at the polar extreme of their distribution, is identified: adjustment of the suitable feeding area. This adjustment is linked closely to community dynamics and increased stock productivity.
Observational determination of albedo decrease caused by vanishing Arctic sea ice
Authors: Pistone Kristina , Eisenman Ian , Ramanathan V.
Published: February 2014

Significance

The Arctic sea ice retreat has been one of the most dramatic climate changes in recent decades. Nearly 50 y ago it was predicted that a darkening of the Arctic associated with disappearing ice would be a consequence of global warming. Using satellite measurements, this analysis directly quantifies how much the Arctic as viewed from space has darkened in response to the recent sea ice retreat. We find that this decline has caused 6.4 ± 0.9 W/m
2
of radiative heating since 1979, considerably larger than expectations from models and recent less direct estimates. Averaged globally, this albedo change is equivalent to 25% of the direct forcing from CO
2
during the past 30 y.
Bacterial tubulin TubZ-Bt transitions between a two-stranded intermediate and a four-stranded filament upon GTP hydrolysis
Authors: Montabana Elizabeth A. , Agard David A.
Published: February 2014

Significance

TubZ is a tubulin superfamily member that forms filaments necessary for faithful segregation of certain low copy-number bacterial plasmids. Here, we observe that filament formation of the
Bacillus thuringiensis
TubZ forms completely different filaments depending on the ability of GTP to hydrolyze. Using GTPγS or hydrolysis-blocked mutants results in two-stranded filaments, and polymerization with GTP yields a four-stranded morphology. Through a combination of high-resolution cryo-electron microscopy, light scattering, and mutational analyses, we propose that the two-stranded filament is a prehydrolysis intermediate on-pathway to the posthydrolysis four-stranded form. The density maps also suggest that the C-terminal region not visible in prior crystal structures makes critical interactions in the two-stranded filaments, explaining why even short truncations block polymerization.
Mechanosensitivity is mediated directly by the lipid membrane in TRAAK and TREK1 K
+
channels
Authors: Brohawn Stephen G. , Su Zhenwei , MacKinnon Roderick
Published: February 2014

Significance

Mechanical force opens mechanosensitive ion channels in the cellular membrane to produce electrical signals that underlie sensation of touch, hearing, and other mechanical stimuli. An unanswered question is: How are mechanical forces transmitted to eukaryotic mechanosensitive channels in the membrane? We show that two mechanosensitive ion channels in eukaryotes, TRAAK (K2P4.1) and TREK1 (K2P2.1), are directly opened by mechanical force through the lipid membrane in the absence of all other cellular components. This finding extends the “force-from-lipid” paradigm established in bacterial channels to TRAAK and TREK1, eukaryotic mechanosensors.
Structures of the PutA peripheral membrane flavoenzyme reveal a dynamic substrate-channeling tunnel and the quinone-binding site
Authors: Singh Harkewal , Arentson Benjamin W. , Becker Donald F. , Tanner John J.
Published: February 2014

Significance

Bifunctional enzymes catalyze two sequential reactions of a metabolic pathway using spatially separated and covalently connected active sites. Combining two enzymes into one protein chain creates efficiency because the product of the first reaction can be shuttled directly to the active site, catalyzing the second reaction in a process called substrate channeling. Here, we use X-ray crystallography to elucidate the three-dimensional structural basis of substrate channeling in the proline catabolic pathway. Structures of the bifunctional enzyme proline utilization A (PutA) reveal an elaborate and dynamic tunnel system featuring a 75-Å-long substrate-channeling path that links the two active sites. Furthermore, we have identified the elusive quinone-binding site of PutA, which provides insight into how PutAs interact with the membrane.
Gating of steering signals through phasic modulation of reticulospinal neurons during locomotion
Authors: Kozlov Alexander K. , Kardamakis Andreas A. , Hellgren Kotaleski Jeanette , Grillner Sten
Published: February 2014

Significance

In many vertebrate and invertebrate species descending motor commands are phasically modulated in synchrony with rhythmic movements. The physiological role of this modulation has remained enigmatic. We report here, from the lamprey locomotor system, that steering signals from for instance tectum can be gated by a downstream locomotor-related modulation of the reticulospinal command neurons. Such gating will ascertain that the steering commands will be transmitted in the appropriate phase of a swimming cycle and be suppressed out-of-phase. Another consequence of this mechanism is the relative independence of the motor response on the timing of the steering signal.
Crazy creative metaphors
Authors: Gibbs Raymond W. , Okonski Lacey , Hatfield Miles
Published: February 2014

This article presents an analysis of public interviews with the American actor Charlie Sheen during a difficult time in his life when he appeared to be speaking and acting crazy. Sheen’s metaphoric descriptions of his life mostly referred to common conventional metaphoric concepts. However, closer examination of the metaphoric discourse revealed that he characterized his life and thoughts using various allegorical themes, most of which relate to fantasy characters, and thought of himself as a special destructive machine. Sheen may possibly have been experiencing the symptoms of certain mental disorders. But we argue that his metaphoric discourse was creative and coherent through his engaging in allegorical thought which is grounded in common embodied simulation processes.
The GOOD IS LIGHT and BAD IS DARK metaphor in feature films
Authors: Forceville Charles , Renckens Thijs
Published: February 2014

Light and darkness can be used metaphorically to help structure good and bad in all media, but film is particularly suitable for exploiting such metaphors. On the basis of examples from three feature films, we discuss in what way the metaphor functions in general and suggest how it allows for a degree of creative play. Moreover, it is pointed out how the metaphor usually interacts with other narratologically salient elements in order to achieve its specific, context-dependent effects. The paper ends with suggestions how the study of this and other conceptual metaphors in film may benefit both metaphor and film scholarship.
Pictorial metonymy as creativity source in “Purificación García” advertising campaigns
Authors: Villacañas Beatriz , White Michael
Published: February 2014

This article examines “Purificación García” advertising campaigns from 1999 to 2013, showing them to be consistently driven by pictorial metonymy. The campaigns systematically use pictorial images, dispensing with ad hoc explanatory linguistic material and do not portray end commercial products. Initial puzzlement is offset by the perception of a metonymic link that leads to the textile world in all cases. Our analysis reveals three recurrent structural patterns: two distinct metonymy sources, metonymic blends arising from the co-occurrence of the two metonymic sources and metonymy motivating metaphor. We argue that the maintenance of this strategy over the years establishes a family resemblance with successive campaigns setting up an anaphoric relationship with preceding ones, thereby mitigating puzzlement and favouring understanding. Creativity derives from the figurative twists given to literally mundane objects, from the metonymic sources, their blends and from the resulting metaphors.
Situated-‘instant’ metaphors
Authors: Romano Manuela
Published: February 2014

This paper studies the metaphorical expressions created as slogans by the Spanish protesters who gathered spontaneously in Madrid’s Puerta del Sol Square on May 15th 2011 to demand economic equality and democracy. The metaphors analysed aresituatedandcontext-induced, as well as ‘instant’, as they were produced in a very short, concrete period of time; in a specific physical location — the Puerta del Sol Square, Madrid; and within an equally specific socio-cultural situation — a political and economic crisis. In addition, the metaphors were created within a more general Spanish socio-cultural context, clearly shown in the slogans. The analysis reveals a variety of linguistic and multimodal mechanisms that interact with contextual factors resulting in a series of creative multimodal metaphors. This creativity actually fulfils a number of significant discourse-pragmatic functions, from attracting attention to etching in memory, but most of all, they are conceived as powerful rhetorical tools that help others to perceive reality in a new perspective and try to persuade people to join the movement and influence politicians and decision makers.