bluuebunny/crossref_metadata_2025 huggingface dataset:
Neither State or Trait Anxiety Alter the Response to Distracting Emotionally Neutral Sounds
Authors: Hoskin Robert , Hunter Mike D. , Woodruff Peter W. R.
Published: August 2014

Attentional control theory suggests that heightened anxiety, whether due to trait or state factors, causes an increased vulnerability to distraction even when the distracters are emotionally neutral. Recent passive oddball studies appear to support this theory in relation to the distraction caused by emotionally neutral sounds. However such studies have manipulated emotional state via the content of task stimuli, thus potentially confounding changes in emotion with differences in task demands. To identify the effect of anxiety on the distraction caused by emotionally neutral sounds, 50 participants completed a passive oddball task requiring emotionally neutral sounds to be ignored. Crucially, state anxiety was manipulated independent of the task stimuli (via unrelated audiovisual stimuli) thus removing confounds relating to task demands. Neither state or trait anxiety was found to influence the susceptibility to distraction by emotionally neutral sounds. These findings contribute to the ongoing debate concerning the impact of emotion on attention.
Specific antibody binding to the APP672–699 region shifts APP processing from α- to β-cleavage
Authors: Li S , Deng J , Hou H , Tian J , Giunta B , Wang Y , Sawmiller D , Smith A , Sanberg P R , Obregon D , Mori T , Tan J
Published: August 2014

Alzheimer’s disease (AD), a progressive neurodegenerative disorder that is the most common cause of dementia in the elderly, is characterized by the accumulation of amyloid-β (Aβ) plaques and neurofibrillary tangles, as well as a progressive loss of synapses and neurons in the brain. The major pertinacious component of amyloid plaques is Aβ, a variably sized peptide derived from the integral membrane protein amyloid precursor protein (APP). The Aβ region of APP locates partly within its ecto- and trans-membrane domains. APP is cleaved by three proteases, designated as α-, β-, and γ-secretases. Processing by β- and γ-secretase cleaves the N- and C-terminal ends of the Aβ region, respectively, releasing Aβ, whereas α-secretase cleaves within the Aβ sequence, releasing soluble APPα (sAPPα). The γ-secretase cleaves at several adjacent sites to yield Aβ species containing 39–43 amino acid residues. Both α- and β-cleavage sites of human wild-type APP are located in APP672–699 region (ectodomain of β-C-terminal fragment, ED-β-CTF or ED-C99). Therefore, the amino acid residues within or near this region are definitely pivotal for human wild-type APP function and processing. Here, we report that one ED-C99-specific monoclonal antibody (mAbED-C99) blocks human wild-type APP endocytosis and shifts its processing from α- to β-cleavage, as evidenced by elevated accumulation of cell surface full-length APP and β-CTF together with reduced sAPPα and α-CTF levels. Moreover, mAbED-C99 enhances the interactions of APP with cholesterol. Consistently, intracerebroventricular injection of mAbED-C99 to human wild-type APP transgenic mice markedly increases membrane-associated β-CTF. All these findings suggest that APP672–699 region is critical for human wild-type APP processing and may provide new clues for the pathogenesis of sporadic AD.
Heparin-induced conformational changes of fibronectin within the extracellular matrix promote hMSC osteogenic differentiation
Authors: Li Bojun , Lin Zhe , Mitsi Maria , Zhang Yang , Vogel Viola
Published: August 2014

Heparin switches the conformation of relaxed fibrillar fibronectin. This conformation upregulates osteogenic differentiation of hMSCs, but only when locked-in by fixation.
WS2 2D nanosheets in 3D nanoflowers
Authors: Prabakaran Arunvinay , Dillon Frank , Melbourne Jodie , Jones Lewys , Nicholls Rebecca J. , Holdway Phil , Britton Jude , Koos Antal A. , Crossley Alison , Nellist Peter D. , Grobert Nicole
Published: August 2014

WS2 nanoflower (false colour).
The effect of ALD-Zno layers on the formation of CH3NH3PbI3 with different perovskite precursors and sintering temperatures
Authors: Dong Xu , Hu Hongwei , Lin Bencai , Ding Jianning , Yuan Ningyi
Published: August 2014

The PCE of perovskite solar cell based on ALD-ZnO reached 13.1%; CH3NH3Cl promoted the formation of CH3NH3PbI3 on 70 °C-ALD-ZnO films.
N-doped carbon spheres with hierarchical micropore-nanosheet networks for high performance supercapacitors
Authors: Wang Shoupei , Zhang Jianan , Shang Pei , Li Yuanyuan , Chen Zhimin , Xu Qun
Published: August 2014

N-doped carbon spheres with hierarchical micropore-nanosheet networks (HPSCSs) with ultrahigh electrochemical performance were prepared by a facile carbonization and activation process.
Visible light-promoted metal-free sp3-C–H fluorination
Authors: Xia Ji-Bao , Zhu Chen , Chen Chuo
Published: August 2014

Photoexcited acetophenone can catalyze the fluorination of unactivated C(sp3)–H groups.
A multimeric MR-optical contrast agent for multimodal imaging
Authors: Harrison Victoria S. R. , Carney Christiane E. , Macrenaris Keith W. , Meade Thomas J.
Published: August 2014

We describe the design, synthesis and in vitro evaluation of a multimodal and multimeric contrast agent.
Interplay of chemical structure and magnetic order coupling at the interface between Cr2O3 and Fe3O4 in hybrid nanocomposites
Authors: Otero-Lorenzo Ruth , Weber Mads C. , Thomas Pamela A. , Kreisel Jens , Salgueiriño Verónica
Published: August 2014

Nanocomposites based on ferrimagnetic Fe3O4 and magnetoelectric antiferromagnetic Cr2O3 nanocrystals offer a particular three-dimensional interface because of chemical intermixing and magnetic coupling.
Pressure induced speciation changes in the aqueous Al3+ system
Authors: Bogatko Stuart , Geerlings Paul
Published: August 2014

We present a new 1st-principles method to study aqueous Al3+ speciation under high pressure using Al(OH)x(H2O)y(3−x)+ clusters and Planck's equation.
Geometric and electronic properties of graphene modified by “external” N-containing groups
Authors: Wang Xinde , Cai Qiuxia , Zhuang Guilin , Zhong Xing , Mei Donghai , Li Xiaonian , Wang Jianguo
Published: August 2014

Due to electron transfer fromortho-carbon to nitrogen, theortho-carbon is the most stable binding site between pyridine derivatives and graphene or the catalytic site for a lot of reactions.
Construction of high efficiency non-doped deep blue emitters based on phenanthroimidazole: remarkable substitution effects on the excited state properties and device performance
Authors: Wang Zhiming , Feng Ying , Zhang Shitong , Gao Yu , Gao Zhao , Chen Yanming , Zhang Xiaojuan , Lu Ping , Yang Bing , Chen Ping , Ma Yuguang , Liu Shiyong
Published: August 2014

Remarkable substitution effects on the excited state properties and device performance are observed by tuning the coupling position.
Mononuclear complexes of amide-based ligands containing appended functional groups: role of secondary coordination spheres on catalysis
Authors: Bansal Deepak , Kumar Gulshan , Hundal Geeta , Gupta Rajeev
Published: August 2014

Coordination complexes of amide-based ligands with appended heterocyclic rings create a hydrogen bonding cavity that effectively binds the substrate(s). Such cavity-based complexes function as reusable and heterogeneous catalysts for various organic transformations.
Geometric asymmetry driven Janus micromotors
Authors: Zhao Guanjia , Pumera Martin
Published: August 2014

A chemically homogeneous “coconut” micromotor made of platinum shows asymmetric motion because its convex surface is capable of generating oxygen bubbles.
A small synthetic molecule forms selective potassium channels to regulate cell membrane potential and blood vessel tone
Authors: Zha Hui-Yan , Shen Bing , Yau Kwok-Hei , Li Shing-To , Yao Xiao-Qiang , Yang Dan
Published: August 2014

A molecule forms a K+-selective channel in the cell membrane to regulate vascular muscle cell membrane potential and blood vessel tone.
Polycrystalline boron nitride constructed from hexagonal boron nitride
Authors: Xu N. , Li J. F. , Huang B. L. , Wang B. L.
Published: August 2014

Two classes of structural families of boron nitride allotropes (named as X-BNs and L-BNs) are proposed to shed light on the polycrystalline structure of high pressure h-BN.
A novel pyrene-2-(pyridin-2-ylmethylsulfanyl)ethylamine based turn-on dual sensor for Al3+: experimental and computational studies
Authors: Bhowmick Rahul , Dolai Malay , Alam Rabiul , Mistri Tarun , Katarkar Atul , Chaudhuri Keya , Ali Mahammad
Published: August 2014

A pyrene based pyrene-2-(pyridin-2-ylmethylsulfanyl)-ethylamine (PP) is found to exhibit a turn-on chemo- and fluorogenic dual sensing of Al3+ through PET blocking and CHEF effect.
Monodisperse PDLC composites generated by use of polyvinyl alcohol boric acid as matrix
Authors: Marin Luminita , Ailincai Daniela , Paslaru Elena
Published: August 2014

PDLC composites with narrow size polydispersity and radial droplet configuration were obtained using polyvinyl alcohol boric acid as carrying matrix.
Heterolytic cleavage of H2 by bifunctional manganese(i) complexes: impact of ligand dynamics, electrophilicity, and base positioning
Authors: Hulley Elliott B. , Helm Monte L. , Bullock R. Morris
Published: August 2014

A balance of metal electrophilicity and ligand steric influences is required for facile, reversible H–H heterolytic cleavage in Mn complexes with pendant amines.
Carbon nanotube based elastomer composites – an approach towards multifunctional materials
Authors: Ponnamma Deepalekshmi , Sadasivuni Kishor Kumar , Grohens Yves , Guo Qipeng , Thomas Sabu
Published: August 2014

The current study focuses on giving a basic understanding of tubular graphene sheets or carbon nanotubes (CNTs) and points towards their role in fabricating elastomer composites.
Rigorous evaluation of propagation losses in arbitrarily shaped waveguide structures using boundary integral – resonant mode expansion and perturbation of boundary conditions
Authors: Marini Stephan , Soto Pablo , Mattes Michael , Gimeno Benito , Bleda Sergio , Vidal Ana , Boria Vicente E.
Published: August 2014

The accurate consideration of propagation losses in arbitrarily shaped waveguide‐based structures is studied in this paper. For such a purpose, a software tool based on the perturbation of the boundary conditions on the waveguide metallic walls and on the boundary integral – resonant mode expansion method has been developed. To show the advantages of the proposed technique with respect to the classic power‐loss method, the complex propagation wavenumbers of a double ridge and an elliptical waveguide have been first computed and compared with results of a commercial software based on the finite element technique. Next a circular, a sectorial shaped and a triangular shaped waveguide have been considered. Then, a computer‐aided design software package based on this modal analysis tool has been applied to predict the propagation loss effects in complex waveguide structures, such as an evanescent mode ridge waveguide filter, a traditional dual mode filter with circular cavities and a twist component for K‐band applications.
Brownian aggregation rate of colloid particles with several active sites
Authors: Nekrasov Vyacheslav M. , Polshchitsin Alexey A. , Yurkin Maxim A. , Yakovleva Galina E. , Maltsev Valeri P. , Chernyshev Andrei V.
Published: August 2014

We theoretically analyze the aggregation kinetics of colloid particles with several active sites. Such particles (so-called “patchy particles”) are well known as chemically anisotropic reactants, but the corresponding rate constant of their aggregation has not yet been established in a convenient analytical form. Using kinematic approximation for the diffusion problem, we derived an analytical formula for the diffusion-controlled reaction rate constant between two colloid particles (or clusters) with several small active sites under the following assumptions: the relative translational motion is Brownian diffusion, and the isotropic stochastic reorientation of each particle is Markovian and arbitrarily correlated. This formula was shown to produce accurate results in comparison with more sophisticated approaches. Also, to account for the case of a low number of active sites per particle we used Monte Carlo stochastic algorithm based on Gillespie method. Simulations showed that such discrete model is required when this number is less than 10. Finally, we applied the developed approach to the simulation of immunoagglutination, assuming that the formed clusters have fractal structure.
Theoretical investigation of intersystem crossing between the $\tilde{a}\,^1A_1$ãA11 and $\tilde{X}\,^3B_1$X̃B13 states of CH2 induced by collisions with helium
Authors: Ma Lifang , Alexander Millard H. , Dagdigian Paul J.
Published: August 2014

Collisional energy transfer between the ground (\documentclass[12pt]{minimal}\begin{document}$\tilde{X}\,^3B_1$\end{document}X̃B13) and first excited (\documentclass[12pt]{minimal}\begin{document}$\tilde{a}\, ^1A_1$\end{document}ãA11) states of CH2 is facilitated by strong mixing of the rare pairs of accidentally degenerate rotational levels in the ground vibrational manifold of the \documentclass[12pt]{minimal}\begin{document}$\tilde{a}$\end{document}ã state and the (020) and (030) excited bending vibrational manifolds of the \documentclass[12pt]{minimal}\begin{document}$\tilde{X}$\end{document}X̃ state. The simplest model for this process involves coherent mixing of the scattering T-matrix elements associated with collisional transitions within the unmixed \documentclass[12pt]{minimal}\begin{document}$\tilde{a}$\end{document}ã and \documentclass[12pt]{minimal}\begin{document}$\tilde{X}$\end{document}X̃ states. From previous calculations in our group, we have determined cross sections and room-temperature rate constants for intersystem crossing of CH2 by collision with He. These are used in simulations of the time dependence of the energy flow, both within and between the \documentclass[12pt]{minimal}\begin{document}$\tilde{X}$\end{document}X̃ and \documentclass[12pt]{minimal}\begin{document}$\tilde{a}$\end{document}ã vibronic manifolds. Relaxation proceeds through three steps: (a) rapid equilibration of the two mixed-pair levels, (b) fast relaxation within the \documentclass[12pt]{minimal}\begin{document}$\tilde{a}$\end{document}ã state, and (c) slower relaxation among the levels of the \documentclass[12pt]{minimal}\begin{document}$\tilde{X}$\end{document}X̃ state. Collisional transfer between the fine-structure levels of the triplet (\documentclass[12pt]{minimal}\begin{document}$\tilde{X}$\end{document}X̃) state is very slow.
Structure and aggregation in model tetramethylurea solutions
Authors: Gupta Rini , Patey G. N.
Published: August 2014

The structure of model aqueous tetramethylurea (TMU) solutions is investigated employing large-scale (32 000, 64 000 particles) molecular dynamics simulations. Results are reported for TMU mole fractions, Xt, ranging from infinite dilution up to 0.07, and for two temperatures, 300 and 330 K. Two existing force fields for TMU-water solutions are considered. These are the GROMOS 53A6 united-atom TMU model combined with SPC/E water [TMU(GROMOS-UA)/W(SPC/E)], and the more frequently employed AMBER03 all-atom force field for TMU combined with the TIP3P water model [TMU(AMBER-AA)/W(TIP3P)]. It is shown that TMU has a tendency towards aggregation for both models considered, but the tendency is significantly stronger for the [TMU(AMBER-AA)/W(TIP3P)] force field. For this model signs of aggregation are detected at Xt = 0.005, aggregation is a well established feature of the solution at Xt = 0.02, and the aggregates increase further in size with increasing concentration. This is in agreement with at least some experimental studies, which report signals of aggregation in the low concentration regime. The TMU aggregates exhibit little structure and are simply loosely ordered, TMU-rich regions of solution. The [TMU(GROMOS-UA)/W(SPC/E)] model shows strong signs of aggregation only at higher concentrations (Xt ≳ 0.04), and the aggregates appear more loosely ordered, and less well-defined than those occurring in the [TMU(AMBER-AA)/W(TIP3P)] system. For both models, TMU aggregation increases when the temperature is increased from 300 to 330 K, consistent with an underlying entropy driven, hydrophobic interaction mechanism. At Xt = 0.07, the extra-molecular correlation length expected for microheterogeneous solutions has become comparable with the size of the simulation cell for both models considered, indicating that even the systems simulated here are sufficiently large only at low concentrations.
Testing procedures for extracting fluctuation spectra from lipid bilayer simulations
Authors: Albert Joseph C. , Ray Lucas T. , Nagle John F.
Published: August 2014

To address concerns about how to obtain the height-height spectrum from simulations of biomembranes, we emulated the fluctuations in real space using exact input spectra. Two different methods that have given different results in the literature were then used to extract spectra from the emulated fluctuations that were then compared to the exact input spectra. A real space method shows systematic, but small deviations attributed to splines introducing an artifactual filter. A direct Fourier method obtains accurate results when the in-plane placement of the emulated particles is uncorrelated with the out-of-plane undulations, but systematic underestimates occur when the particle placement is more realistically correlated with the undulations. Although quantitative corrections cannot be estimated from our one-dimensional model, the results are qualitatively consistent with the direct Fourier method underestimating the 1/q2 spectral dependence that is characteristic of a tilt degree of freedom in simulations.
Coaxial pellets for metallic impurity injection on the large helical device
Authors: Huang X. L. , Morita S. , Oishi T. , Goto M. , Zhang H. M.
Published: August 2014

Two coaxial pellets with tungsten inserted into graphite carbon and polyethylene (PE) tubes are compared for tungsten spectroscopic study in the Large Helical Device. The tungsten pellet with carbon tube causes plasma collapse, while that with PE tube smoothly ablates without collapse. The deposition profile of the pellets is analyzed with a help of pellet ablation spectroscopy. It is found that the tungsten pellet with carbon tube can significantly penetrate into the core plasma and leads to the plasma collapse. A tungsten spectrum with radial profile is successfully observed when the tungsten pellet with PE tube is used.
Fluorescence imaging of viscous materials in the ultraviolet-visible wavelength range
Authors: Murr Patrik J. , Rauscher Markus S. , Tremmel Anton , Schardt Michael , Koch Alexander W.
Published: August 2014

This paper presents an approach of an innovative measurement principle for the quality control of viscous materials during a manufacturing process based on fluorescence imaging. The main contribution to the state of the art provided by this measurement system is that three equal fluorescence images of a static or moving viscous object are available in different optical paths. The independent images are obtained by two beam splitters which are connected in series. Based on these images, it is possible to evaluate each image separately. In our case, three optical bandpass filters with different center wavelengths of 405 nm, 420 nm, and 440 nm were used to filter the separate fluorescence images. The developed system is useable for the detection of impurities in the micrometer range. Further, incorrect mixing ratios of particular components and wrong single components in the viscous materials can be detected with the setup. Moreover, it is possible to realize static and dynamic measurements. In this case the maximum speed of the objects was 0.2 m/s for the dynamic measurements. Advantages of this measurement setup are the universality due to the use of optical standard components, the small dimension and the opportunity to integrate it easily into ongoing processes. In addition, the measurement system works on a non-contact basis. Thus, the expense for maintenance is at a very low level compared to currently available measurement setups for the investigated application. Furthermore, the setup provides for the first time a simultaneous analysis of more than one component and the detection of impurities concerning their nature and size in a manufacturing process.
Atomic-scale investigation of point defects and hydrogen-solute atmospheres on the edge dislocation mobility in alpha iron
Authors: Bhatia M. A. , Groh S. , Solanki K. N.
Published: August 2014

In this study, we present atomistic mechanisms of 1/2 [111](11¯0) edge dislocation interactions with point defects (hydrogen and vacancies) and hydrogen solute atmospheres in body centered cubic (bcc) iron. In metals such as iron, increases in hydrogen concentration can increase dislocation mobility and/or cleavage-type decohesion. Here, we first investigate the dislocation mobility in the presence of various point defects, i.e., change in the frictional stress as the edge dislocation interacts with (a) vacancy, (b) substitutional hydrogen, (c) one substitutional and one interstitial hydrogen, (d) interstitial hydrogen, (e) vacancy and interstitial hydrogen, and (f) two interstitial hydrogen. Second, we examine the role of a hydrogen-solute atmosphere on the rate of local dislocation velocity. The edge dislocation simulation with a vacancy in the compression side of the dislocation and an interstitial hydrogen atom at the tension side exhibit the strongest mechanical response, suggesting a higher potential barrier and hence, the higher frictional stress (i.e., ∼83% higher than the pure iron Peierls stress). In the case of a dislocation interacting with a vacancy on the compressive side, the vacancy binds with the edge dislocation, resulting in an increase in the friction stress of about 28% when compared with the Peierls stress of an edge dislocation in pure iron. Furthermore, as the applied strain increases, the vacancy migrates through a dislocation transportation mechanism by attaining a velocity of the same order as the dislocation velocity. For the case of the edge dislocation interacting with interstitial hydrogen on the tension side, the hydrogen atom jumps through one layer perpendicular to the glide plane during the pinning-unpinning process. Finally, our simulation of dislocation interactions with hydrogen show first an increase in the local dislocation velocity followed by a pinning of the dislocation core in the atmosphere, resulting in resistance to dislocation motion as the dislocation moves though the hydrogen-solute atmospheres. With this systematic, atomistic study of the edge dislocation with various point defects, we show significant increase in obstacle strengths in addition to an increase in the local dislocation velocity during interaction with solute atmospheres. The results have implications for constitutive development and modeling of the hydrogen effect on dislocation mobility and deformation in metals.
Experimental indication for band gap widening of chalcopyrite solar cell absorbers after potassium fluoride treatment
Authors: Pistor P. , Greiner D. , Kaufmann C. A. , Brunken S. , Gorgoi M. , Steigert A. , Calvet W. , Lauermann I. , Klenk R. , Unold T. , Lux-Steiner M.-C.
Published: August 2014

The implementation of potassium fluoride treatments as a doping and surface modification procedure in chalcopyrite absorber preparation has recently gained much interest since it led to new record efficiencies for this kind of solar cells. In the present work, Cu(In,Ga)Se2 absorbers have been evaporated on alkali containing Mo/soda-lime glass substrates. We report on compositional and electronic changes of the Cu(In,Ga)Se2 absorber surface as a result of a post deposition treatment with KF (KF PDT). In particular, by comparing standard X-ray photoelectron spectroscopy and synchrotron-based hard X-ray photoelectron spectroscopy (HAXPES), we are able to confirm a strong Cu depletion in the absorbers after the KF PDT which is limited to the very near surface region. As a result of the Cu depletion, we find a change of the valence band structure and a shift of the valence band onset by approximately 0.4 eV to lower binding energies which is tentatively explained by a band gap widening as expected for Cu deficient compounds. The KF PDT increased the open circuit voltage by 60–70 mV compared to the untreated absorbers, while the fill factor deteriorated.
Energy dissipation in edged and edgeless graphene mechanical resonators
Authors: Takamura Makoto , Okamoto Hajime , Furukawa Kazuaki , Yamaguchi Hiroshi , Hibino Hiroki
Published: August 2014

We examined the temperature (T) dependence of the inverse of quality factors (Q−1) of edged and edgeless graphene resonators to evaluate energy dissipation in these resonators. We found that Q−1 in an edgeless drumhead resonator shows a linear T dependence in a wide range of 20–300 K, while that in an edged doubly clamped resonator shows T2 and T0.3 dependence above and below ∼100 K, respectively. On the basis of these experimental results, and by comparing them with the previous experimental and numerical studies, we discuss the energy dissipation mechanisms in these resonators. The dissipation at free edges causes the T0.3 dependence in the lower temperature regime, and tensile strain due to the thermal contraction of the clamped-end metal will lead to the T2 behavior in the higher temperature regime. We demonstrate that elimination of these dissipation sources provides wide-ranging linear-T dependence of Q−1 in our drumhead resonators.
Optically and elastically assembled plasmonic nanoantennae for spatially resolved characterization of chemical composition in soft matter systems using surface enhanced spontaneous and stimulated Raman scattering
Authors: Mundoor Haridas , Lee Taewoo , Gann Derek G. , Ackerman Paul J. , Senyuk Bohdan , van de Lagemaat Jao , Smalyukh Ivan I.
Published: August 2014

We present a method to locally probe spatially varying chemical composition of soft matter systems by use of optically controlled and elastically self-assembled plasmonic nanoantennae. Disc-shaped metal particles with sharp irregular edges are optically trapped, manipulated, and assembled into small clusters to provide a strong enhancement of the Raman scattering signal coming from the sample regions around and in-between these particles. As the particles are reassembled and spatially translated by computer-controlled laser tweezers, we probe chemical composition as a function of spatial coordinates. This allows us to reliably detect tiny quantities of organic molecules, such as capping ligands present on various nanoparticles, as well as to probe chemical composition of the interior of liquid crystal defect cores that can be filled with, for example, polymer chains. The strong electromagnetic field enhancement of optically manipulated nanoparticles' rough surfaces is demonstrated in different forms of spectroscopy and microscopy, including enhanced spontaneous Raman scattering, coherent anti-Stokes Raman scattering, and stimulated Raman scattering imaging modes.
The lumped equivalent circuit model of the multi-passband tunable microwave magnetoelectric filters
Authors: Zhou Hao-Miao , Lian Jing , Zhu Feng-Jie
Published: August 2014

A magnetoelectric tunable microwave filter is proposed, which has multi-passband at corresponding frequencies when different magnetic fields are applied on multi-magnetoelectric laminates. A generalized lumped equivalent circuit model for the filter is established to predict the transmission characteristics. For existing experimental results of the microstrip filter with one magnetoelectric laminate put on the coupling microstrip lines, therefore the lumped circuit model is degraded. And the validity of the model is confirmed from the result that the predictions of the model are in good agreement with the results obtained by the electromagnetic simulation software and experimental results. Then, the performance of the multi-passband microwave filter with a plurality of magnetoelectric laminates is studied by the lumped equivalent circuit. It is found that any single band of multi-passband can be tunable through controlling the applied field on a block of magnetoelectric laminate, which can improve the practicability and flexibility of the bandpass filter. Moreover, when the same field is applied on the magnetoelectric laminates, the multi-passband will be combined into a single passband. The combined single passband has significantly larger bandwidth than the corresponding bandwidth of the filter, which has a single laminate with the same applied field, which can improve the bandpass effect obviously.
Structure and electronic properties of mixed (a + c) dislocation cores in GaN
Authors: Horton M. K. , Rhode S. L. , Moram M. A.
Published: August 2014

Classical atomistic models and atomic-resolution scanning transmission electron microscopy studies of GaN films reveal that mixed (a + c)-type dislocations have multiple different core structures, including a dissociated structure consisting of a planar fault on one of the {12¯10} planes terminated by two different partial dislocations. Density functional theory calculations show that all cores introduce localized states into the band gap, which affects device performance.
Oxygen vacancies and their effects on tilting transition in perovskite (La1−xPrx)1/3Sr2/3FeO3−δ investigated by mechanical spectroscopy
Authors: Xu Z. C. , Chen C. C. , Ying X. N.
Published: August 2014

We present the results of kilohertz mechanical spectrum of perovskite (La1−xPrx)1/3Sr2/3FeO3−δ (x = 0 to 1) samples. An oxygen vacancy related internal friction peak was observed around 400 K in oxygen nonstoichiometric La1/3Sr2/3FeO3−δ and Pr1/3Sr2/3FeO3−δ samples. An octahedral tilting Pm3¯m↔R3¯c transition appeared as a step-like decrease of modulus with the decrease in temperature in less oxygen nonstoichiometric (La1−xPrx)1/3Sr2/3FeO3−δ samples. Another unsymmetrical internal friction peak due to the relaxation of domain walls was observed just below the tilting transition. The different behavior of oxygen vacancies and their complicate interaction with ferroelastic domains were suggested in various oxygen nonstoichiometric La1/3Sr2/3FeO3−δ and Pr1/3Sr2/3FeO3−δ samples.
Evaluation of the relationship between the effective strain and the springback behavior during the deformation of metallic glass ribbons
Authors: Lee M. H. , Park E. S. , Ott R. T. , Kim B. S. , Eckert J.
Published: August 2014

We evaluated the role of effective strain on the plasticity of metallic glasses related to springback phenomena in both ductile Zr-based metallic glass and brittle Hf-based metallic glass. Experimental investigations of the deformation behavior and the intrinsic mechanical properties of metallic glass were performed by room temperature L-bending deformation. The modeling analysis clearly shows that an inhomogeneous effective strain for initiating shear band is generated during deformation, with the brittleness of a metallic glass being dependent on the effective strain reaching the critical fracture strain of the glass. The combined experimental and modeling results reveal broad and general criteria that should allow for deformability of a wide-variety of glass-forming alloys by adjusting the effective strain during deformation.
Detection of nonlinear picosecond acoustic pulses by time-resolved Brillouin scattering
Authors: Gusev Vitalyi E.
Published: August 2014

In time-resolved Brillouin scattering (also called picosecond ultrasonic interferometry), the time evolution of the spatial Fourier component of an optically excited acoustic strain distribution is monitored. The wave number is determined by the momentum conservation in photon-phonon interaction. For linear acoustic waves propagating in a homogeneous medium, the detected time-domain signal of the optical probe transient reflectivity shows a sinusoidal oscillation at a constant frequency known as the Brillouin frequency. This oscillation is a result of heterodyning the constant reflection from the sample surface with the Brillouin-scattered field. Here, we present an analytical theory for the nonlinear reshaping of a propagating, finite amplitude picosecond acoustic pulse, which results in a time-dependence of the observed frequency. In particular, we examine the conditions under which this information can be used to study the time-evolution of the weak-shock front speed. Depending on the initial strain pulse parameters and the time interval of its nonlinear transformation, our theory predicts the detected frequency to either be monotonically decreasing or oscillating in time. We support these theoretical predictions by comparison with available experimental data. In general, we find that picosecond ultrasonic interferometry of nonlinear acoustic pulses provides access to the nonlinear acoustic properties of a medium spanning most of the GHz frequency range.
New position of Dirac points in the strained graphene reciprocal lattice
Authors: Li Cui-Lian
Published: August 2014

In the strained graphene, Fermi velocity shows space-dependent and it changes as the position of Dirac point shifts. In this paper, we apply the tight-binding approach within linear elasticity theory to investigate the shifting of Dirac points in the strained graphene reciprocal lattice space. Based on this, we derive the analytical expression on the new positions of the Dirac points as the strain parameter varies. Comparing the data from our analytical expression, ones from Eq. (20) in Phys. Rev. B 80, 045401 (2009), and those from numerical calculation, we find that our analytical expression raises the effective prediction range of the strain parameter from 3% to 15%. i.e., our analytical expression is practicable until the strain parameter is larger than 15%. This almost includes the whole range where the Dirac points present and the energy gap is zero. Moreover, we further calculate the energy gap by numerical method when the shear strain parameter varies from 0 to 20%, and find that the energy gap can not open until the strain parameter is larger than 16%. After this, the energy gap open and the Dirac points disappear.
Enhanced ultraviolet electroluminescence and spectral narrowing from ZnO quantum dots/GaN heterojunction diodes by using high-k HfO2 electron blocking layer
Authors: Mo Xiaoming , Long Hao , Wang Haoning , Li Songzhan , Chen Zhao , Wan Jiawei , Feng Yamin , Liu Yuping , Ouyang Yifang , Fang Guojia
Published: August 2014

We demonstrated the capability of realizing enhanced ZnO-related UV emissions by using the low-cost and solution-processable ZnO quantum dots (QDs) with the help of a high-k HfO2 electron blocking layer (EBL) for the ZnO QDs/p-GaN light-emitting diodes (LEDs). Full-width at half maximum of the LED devices was greatly decreased from ∼110 to ∼54 nm, and recombinations related to nonradiative centers were significantly suppressed with inserting HfO2 EBL. The electroluminescence of the ZnO QDs/HfO2/p-GaN LEDs demonstrated an interesting spectral narrowing effect with increasing HfO2 thickness. The Gaussian fitting revealed that the great enhancement of the Zni-related emission at ∼414 nm whereas the deep suppression of the interfacial recombination at ∼477 nm should be the main reason for the spectral narrowing effect.
Disparate quasiballistic heat conduction regimes from periodic heat sources on a substrate
Authors: Zeng Lingping , Chen Gang
Published: August 2014

We report disparate quasiballistic heat conduction trends for periodic nanoscale line heaters deposited on a substrate, depending upon whether measurements are based on the peak temperature of the heaters or the temperature difference between the peak and the valley of two neighboring heaters. The degree of quasiballistic transport is characterized by the effective thermal conductivities of the substrate which are obtained by matching the diffusion solutions to the phonon Boltzmann transport equation results. We find that while the ballistic heat conduction effect based on the peak temperature diminishes as the two heaters become closer, it becomes stronger based on the peak-valley temperature difference. Our results also show that the collective behavior of closely spaced heaters can counteract the nonlocal effects caused by an isolated nanoscale hot spot. These results are relevant to thermal conductivity spectroscopy techniques under development and also have important implications for understanding nonlocal heat conduction in integrated circuits and carbon nanotube array thermal interface materials.
Magnetic properties and interlayer coupling of epitaxial Co/Cu films on Si
Authors: Mansell R. , Petit D. C. M. C. , Fernández-Pacheco A. , Lavrijsen R. , Lee J. H. , Cowburn R. P.
Published: August 2014

Thin films of Co and Co/Cu/Co trilayers with wedged Cu interlayers were grown epitaxially on Cu buffer layers on hydrogen passivated Si(001) wafers. We find that single Co layers have a well-defined four-fold anisotropy but with smaller in-plane anisotropies than observed in Co grown on Cu crystals. Ruderman–Kittel–Kasuya–Yosida (RKKY) interlayer coupling is observed in one Co/Cu/Co sample which is the smoothest of the films as measured by atomic force microscopy. Some of the films also form a dot-like structure on the surface. Intermixing at elevated temperatures between the Cu buffer and Si limits the ability to form flat surfaces to promote RKKY coupling.
Electrical, magnetic, and magneto-electrical properties in quasi-two-dimensional K0.58RhO2 single crystals doped with rare-earth elements
Authors: Zhang Bin-Bin , Dong Song-Tao , Yao Shu-Hua , Chen Y. B. , Zhang Shan-Tao , Gu Zheng-Bin , Zhou Jian , Lu Ming-Hui , Chen Yan-Feng , Shi Y. G.
Published: August 2014

In this Letter, we studied the electrical transport, magnetic property, magnetoresistance and anomalous Hall properties of La-, Sm-, Ho-, and Dy-doped quasi-two dimensional K0.58RhO2 single crystals. At low temperature (<10 K), a significant magnetoresistance (36%) can be observed in these samples. Accordingly, the “glassy ferromagnetism” is revealed by temperature-dependent magnetization in these samples. The significant magnetoresistance is related to the granular ferromagnetism. The unconventional anomalous Hall effect is also observed in magnetic atoms doped samples. Our finding shields more light on the magnetic, magnetoresistance, and anomalous Hall properties of quasi-two-dimensional material systems doped with magnetic ions.
Seedling mortality during biphasic drought in sandy Mediterranean soils
Authors: Benigno Stephen M. , Dixon Kingsley W. , Stevens Jason C.
Published: August 2014

Climate change is increasing the frequency and intensity of drought, and seedling response to a recurrent pattern of drought stress is necessary to understand vegetation establishment patterns in particularly for ecological restoration and conservation projects. A controlled environment study investigated seedling physiological response of framework Mediterranean tree species to simulated successive droughts. Six-month-old seedlings were grown in 1.0 m tall pots to emulate deep soil profiles and subjected to a well watered treatment and a drought treatment consisting of an initial 60 day drought (water withholding), followed by 120 days of re-watering and a subsequent 60 day drought. Soil water access, soil water content, maximum root depth and xylem water potential were assessed through successive harvests. To assess seedling response to multiple droughts, gas-exchange and chlorophyll fluorescence measurements were taken every 15 days after each drought, and multiple times throughout re-watering. No seedling mortality was observed during the initial drought, whereas 100% mortality of all species occurred within 48 days of the second drought. Seedling gas exchange and water potential decreased with decreasing water availability but was dependent on the isohydric or anisohydric behaviour of individual species. An absence of sustained photoprotection during the second drought phase heightened photodamage to foliar tissues resulting in a more rapid decrease of gs and leaf water potential. Therefore, biphasic drought proved detrimental to seedling establishment by reducing physiological resilience, highlighting the severity of future climate change predictions towards the regeneration capacity of Mediterranean ecosystems.
Plasmonic nanoparticle scattering for color holograms
Authors: Montelongo Yunuen , Tenorio-Pearl Jaime Oscar , Williams Calum , Zhang Shuang , Milne William Ireland , Wilkinson Timothy David
Published: August 2014

Significance

In this work, we demonstrate a multicolor hologram based on plasmonic scattering of nanoparticles that is capable of encoding more information than the spatial bandwidth dictates. This device is designed based on the fundamental concept of diffraction produced by the scattering of arrays of nanoparticles. Hence, when multiple arrays of plasmonic nanoparticles are multiplexed without coupling, they carry independent information such as polarization and wavelength to the far field. The device shown is unique because, to our knowledge, this is the first multichannel diffractive element produced from a single thin film that simultaneously controls two wavelengths in-plane and within subwavelength distances. These results will lead to a new range of applications in diffractive optics, information storage, and 3D displays.
Hampered long-term depression and thin spine loss in the nucleus accumbens of ethanol-dependent rats
Authors: Spiga Saturnino , Talani Giuseppe , Mulas Giovanna , Licheri Valentina , Fois Giulia R. , Muggironi Giulia , Masala Nicola , Cannizzaro Carla , Biggio Giovanni , Sanna Enrico , Diana Marco
Published: August 2014

Significance

This paper examines the intimate neuroarchitecture of the nucleus accumbens shell region and how it affects synaptic plasticity in alcohol-dependent rats. To do so, a simultaneous morphometrical/immunofluorescence method was applied to visualize various types of dendritic spines and patch-clamp techniques to detect changes in synaptic currents. Using these tools, we show a selective loss of “long thin” spines accompanied by an impaired long-term depression (LTD) in alcohol-dependent rats. Dopaminergic and glutamatergic signaling are similarly altered. The results highlight the role of long thin dendritic spines in the genesis of LTD in alcohol dependence.
Genetic–epigenetic dysregulation of thymic TSH receptor gene expression triggers thyroid autoimmunity
Authors: Stefan Mihaela , Wei Chengguo , Lombardi Angela , Li Cheuk Wun , Concepcion Erlinda S. , Inabnet William B. , Owen Randall , Zhang Weijia , Tomer Yaron
Published: August 2014

Significance

Graves disease (GD) is an autoimmune disease caused by interactions between genetic, epigenetic, and environmental factors. The thyrotropin receptor (
TSHR
) is the major autoantigen in GD and is a key GD susceptibility gene. SNPs in intron 1 of the
TSHR
are associated with GD, but the causative variant and the mechanisms are unknown. By mapping epigenetic modifications induced by IFNα, a viral-induced cytokine triggering GD, we pinpointed the causative variant in intron 1 of the
TSHR
. We demonstrate that the disease-associated variant interacts epigenetically with a transcriptional repressor, promyelocytic leukemia zinc finger protein, and reduces thymic
TSHR
expression, leading to escape from tolerance and autoimmunity to the TSHR. These genetic–epigenetic interactions leading to decreased thymic self-antigen expression reveal a universal mechanism in autoimmunity.
Mining for peace: diamonds, bauxite, iron ore and political stability in Guinea
Authors: Bah Mamadou Diouma
Published: August 2014

The article explores the relationship between mineral resources and conflict management in Guinea. Literature on theories of recent civil wars and/or armed conflicts in West Africa identifies the combination of abundant natural resources and extreme poverty as a significant trigger of violent civil conflicts. In Guinea, however, despite this combination, the state has managed to avoid large-scale civil violence. This gives rise to the question of why this combination has failed to be associated with the onset of large-scale violence in the country. The article identifies mitigating factors that have contributed to political stability in Guinea. It concludes that measures taken by Guinea and its international partners mitigated the security threats posed by these resources, while keeping most Guineans in abject poverty. This is in contrast to findings in recent quantitative studies whereby natural resource abundance alongside extreme poverty is strongly associated with armed conflicts in West African nations.
Relationships Between Fatty Acid Contents of Barley Grain, Malt, and Wort with Malt Quality Measurements
Authors: Cozzolino Daniel , Roumeliotis Sophie , Eglinton Jason
Published: August 2014

Although lipids and fatty acids (FA) represent only 1–3% of the grain weight, they can play an important role in regulating, modulating, and determining several chemical and physical properties of the grain and corresponding malts. The aim of this study was to evaluate the relationships between the content of FA in grain, malt, and wort with malt quality characteristics such as hot water extract (HWE) and apparent attenuation limit (AAL) in different commercial malting barley varieties. High and positive correlations were found between myristic acid and HWE (r = 0.71) and between stearic acid and AAL (r = 0.76), with intermediate correlations between palmitic, oleic, linoleic, and linolenic acids and AAL (r = >0.50) in grain. High and negative correlations were found between stearic acid and HWE (r = –0.66), and high and negative correlations were found between palmitic (r = −0.74) and linoleic (r = −0.60) acids and AAL in the wort. Results from this study showed that lipids, as well as the combination of unsaturated and saturated FA, might play a role in determining differences in HWE and AAL between the barley varieties analyzed. No clear evidence on HWE was observed when grain and malt samples from the same variety were compared. These results indicated that lipids and FA should be considered together with starch properties to explain differences between HWE and AAL.