bluuebunny/crossref_metadata_2025 huggingface dataset:
Bright solitons in coherently coupled nonlinear Schrödinger equations with alternate signs of nonlinearities
Authors: Sakkaravarthi K. , Kanna T.
Published: January 2013

The exact bright one- and two-soliton solutions of a particular type of coherently coupled nonlinear Schrödinger equations, with alternate signs of nonlinearities among the two components, are obtained using the non-standard Hirota's bilinearization method. We find that in contrary to the coherently coupled nonlinear Schrödinger equations with same signs of nonlinearities the present system supports only coherently coupled solitons arising due to an interplay between dispersion and the nonlinear effects, namely, self-phase modulation, cross-phase modulation, and four-wave mixing process, thereby depend on the phases of the two co-propagating fields. The other type of soliton, namely, incoherently coupled solitons which are insensitive to the phases of the co-propagating fields and arise in a similar kind of coherently coupled nonlinear Schrödinger equations but with same signs of nonlinearities are not at all possible in the present system. The present system can support regular solution for the choice of soliton parameters for which mixed coupled nonlinear Schrödinger equations admit only singular solution. Our analysis on the collision dynamics of the bright solitons reveals the important fact that in contrary to the other types of coupled nonlinear Schrödinger systems the bright solitons of the present system can undergo only elastic collision in spite of their multicomponent nature. We also show that regular two-soliton bound states can exist even for the choice for which the same system admits singular one-soliton solution. Another important effect identified regarding the bound solitons is that the breathing effects of these bound solitons can be controlled by tuning the additional soliton parameters resulting due to the multicomponent nature of the system which do not have any significant effects on bright one soliton propagation and also in soliton collision dynamics.
Sub-250 nm light emission and optical gain in AlGaN materials
Authors: Francesco Pecora Emanuele , Zhang Wei , Nikiforov A. Yu. , Yin Jian , Paiella Roberto , Dal Negro Luca , Moustakas Theodore D.
Published: January 2013

We investigate the deep-UV optical emission and gain properties of AlxGa1−xN/AlyGa1−yN multiple quantum wells structures. These structures were grown by plasma-assisted molecular-beam epitaxy on 6H-SiC substrates, under a growth mode which promotes various degrees of band-structure potential fluctuations in the form of cluster-like features within the wells. The degree of inhomogeneities in these samples was determined by cathodoluminescence mapping. We measured the TE-polarized amplified spontaneous emission in the sample with cluster-like features and quantified the optical absorption/gain coefficients and gain spectra by the variable stripe length technique under ultrafast optical pumping. A maximum net modal gain of about 120 cm−1 is measured at 4.9 eV. On the other hand, we found that samples with homogeneous quantum wells lead to absorption. Numerical simulations are performed to support our experimental findings.
First-principles investigation of the size-dependent structural stability and electronic properties of O-vacancies at the ZnO polar and non-polar surfaces
Authors: Mun Wong Kin , Alay-e-Abbas S. M. , Shaukat A. , Fang Yaoguo , Lei Yong
Published: January 2013

In this paper, all electron full-potential linearized augmented plane wave plus local orbitals method has been used to investigate the structural and electronic properties of polar (0001) and non-polar (101¯0) surfaces of ZnO in terms of the defect formation energy (DFE), charge density, and electronic band structure with the supercell-slab (SS) models. Our calculations support the size-dependent structural phase transformation of wurzite lattice to graphite-like structure which is a result of the termination of hexagonal ZnO at the (0001) basal plane, when the stacking of ZnO primitive cell along the hexagonal principle c-axis is less than 16 atomic layers of Zn and O atoms. This structural phase transformation has been studied in terms of Coulomb energy, nature of the bond, energy due to macroscopic electric field in the [0001] direction, and the surface to volume ratio for the smaller SS. We show that the size-dependent phase transformation is completely absent for surfaces with a non-basal plane termination, and the resulting structure is less stable. Similarly, elimination of this size-dependent graphite-like structural phase transformation also occurs on the creation of O-vacancy which is investigated in terms of Coulomb attraction at the surface. Furthermore, the DFE at the (101¯0)/(1¯010) and (0001)/(0001¯) surfaces is correlated with the slab-like structures elongation in the hexagonal a- and c-axis. Electronic structure of the neutral O-vacancy at the (0001)/(0001¯) surfaces has been calculated and the effect of charge transfer between the two sides of the polar surfaces (0001)/(0001¯) on the mixing of conduction band through the 4s orbitals of the surface Zn atoms is elaborated. An insulating band structure profile for the non-polar (101¯0)/(1¯010) surfaces and for the smaller polar (0001)/(0001¯) SS without O-vacancy is also discussed. The results in this paper will be useful for the tuning of the structural and electronic properties of the (0001) and (101¯0) ZnO nanosheets by varying their size.
Effect of surface stress on the stiffness of micro/nanocantilevers: Nanowire elastic modulus measured by nano-scale tensile and vibrational techniques
Authors: Qiao Li , Zheng Xiaojing
Published: January 2013

Surface stress induced stiffness change of micro/nanocantilevers is reviewed and rigorously examined in this work. The self-equilibrium strain field of micro/nanocantilevers carrying an inherent surface stress on substrate is derived by resorting to the generalized Young-Laplace equation. It is found that the mechanism responsible for the observed stiffness change of micro/nano cantilevers originating from surface stress cannot be attributed to the development of in-plane stress near the clamp. Based on the analysis, two loading modes used in the mechanical test experiments performed on nanowire (NW) are theoretically investigated in detail: tension and electrically-induced-vibration. Lattice distortions arising from surface stress, coupled with that induced by residual strain, are shown to play a significant role in the elastic modulus measurement of NWs using an electric-field-induced vibrational mode, but have no influences on the tensile testing mode. The analytical results are validated by comparisons with molecular dynamic simulations and experimental measurements. The present results are useful in interpreting differences in observed size-dependent elasticity of NWs and developing the nano- and micro-mechanical testing techniques.
Interatomic decay of inner-valence ionized states in ArXe clusters: Relativistic approach
Authors: Fasshauer Elke , Pernpointner Markus , Gokhberg Kirill
Published: January 2013

In this work we investigate interatomic electronic decay processes taking place in mixed argon-xenon clusters upon the inner-valence ionization of an argon center. We demonstrate that both interatomic Coulombic decay and electron-transfer mediated decay (ETMD) are important in larger rare gas clusters as opposed to dimers. Calculated secondary electron spectra are shown to depend strongly on the spin-orbit coupling in the final states of the decay as well as the presence of polarizable environment. It follows from our calculations that ETMD is a pure interface process taking place between the argon-xenon layers. The interplay of all these effects is investigated in order to arrive at a suitable physical model for the decay of inner-valence vacancies taking place in mixed ArXe clusters.
Effects of pumping on propagation velocities of confined exciton polaritons in GaAs/AlxGa1−xAs double heterostructure thin films under resonant and non-resonant probe conditions
Authors: Kojima Osamu , Ohta Shohei , Kita Takashi , Isu Toshiro
Published: January 2013

We report the effects of excitation of exciton polaritons on their propagation in GaAs (110 nm)/Al0.3Ga0.7As double heterostructure thin films by measuring the cross-correlation signal, which was recorded as the intensity of the second harmonic light generated by the gate pulse and the probe pulse reflected from the sample. When the probe energy is tuned at the lowest exciton energy, the signal profile changes due to the appearance of nonlinear dispersion. On the other hand, the signal profile shows a complicated change under the non-resonant probe condition, in which the energy is the center energy of two exciton states. These results originate from a change in the propagation velocity of the exciton polariton due to the pump.
Surface-enhanced Raman scattering from finite arrays of gold nano-patches
Authors: Vincenti M. A. , Grande M. , Bianco G. V. , de Ceglia D. , Stomeo T. , De Vittorio M. , Petruzzelli V. , Bruno G. , D'Orazio A. , Scalora M.
Published: January 2013

We experimentally investigate the surface-enhanced Raman scattering (SERS) response of a 2D-periodic array of square gold nano-patches, functionalized by means of a conjugated, rigid thiol. We measure a Raman signal enhancement up to 200 times more intense compared to other plasmon-based nanostructures functionalized with the same molecule, and show that the enhancement is not strictly correlated to the presence of plasmonic resonances. The agreement between experimental and theoretical results reveals the importance of a full-wave analysis based on the inclusion of the actual scattering cross section of the molecule. The proposed numerical approach may serve not only as a tool to predict the enhancement of Raman signal scattered from strongly resonant nanostructure but also as an effective instrument to engineer SERS platforms that target specific molecules.
Structure and phase transitions in 0.5(Ba0.7Ca0.3TiO3)-0.5(BaZr0.2Ti0.8O3) from −100 °C to 150 °C
Authors: Bjørnetun Haugen Astri , Forrester Jennifer S. , Damjanovic Dragan , Li Binzhi , Bowman Keith J. , Jones Jacob L.
Published: January 2013

The solid solution of (x)Ba0.7Ca0.3TiO3-(1-x)BaZr0.2Ti0.8O3 is known to exhibit high piezoelectric constants. Discrepancies in the reported phase transitions and structure around room temperature, however, have complicated the understanding of the enhanced properties. Rietveld refinement of high-resolution X-ray diffraction is employed here to establish and refine the crystallographic structure at temperatures from −100 °C to 150 °C for x = 0.5. A combination of rhombohedral R3m and tetragonal P4mm is found to coexist at temperatures of 20 °C and −25 °C, bordered by single phase rhombohedral and tetragonal regions at lower (i.e., −100 °C) and higher (i.e., 70 °C) temperatures, respectively. The diffractograms also show signs of strain and domain wall scattering that are linked to the sample history.
Large thermal conductivity decrease in point defective Bi2Te3 bulk materials and superlattices
Authors: Termentzidis Konstantinos , Pokropyvnyy Oleksiy , Woda Michael , Xiong Shiyun , Chumakov Yuri , Cortona Pietro , Volz Sebastian
Published: January 2013

Defective Bi2Te3 structures have been studied with the aim of lowering the thermal conductivity in order to improve the thermoelectric figure of merit. The cross-plane thermal conductivities of structures containing point defects have been computed by means of molecular dynamics techniques, finding a maximum decrease of 70% for a 4% concentration of tellurium atom vacancies. Superlattices with modified stoichiometries have also been considered in order to find the configuration having the lowest thermal conductivity. In this case, a maximum decrease of 70% was also found. These predictions open the way to the design of efficient bulk thermoelectric materials having optimised thermal properties similar to those of superlattices.
Charge trapping in [poly-(2-methoxyl),5-(3,77dimethyloctyloxy)] paraphenylenevinylene synthesized in different routes affected by the energetical distribution of trapping states
Authors: Pranaitis M. , Sakavičius A. , Janonis V. , Kažukauskas V.
Published: January 2013

In this study, the thermally stimulated current measurements are used as a direct photoelectrical method to prove distribution of the trapping states in MDMO-PPV ([poly-(2-methoxyl),5-(3,77dimethyloctyloxy)] paraphenylenevinylene) polymers synthesized in the “Gilch” and “Sulfinyl” routes. It was demonstrated that two traps with the Gaussian distribution of the states and effective mean activation energies of about 0.22 and 0.40 eV are prevailing in MDMO-PPV synthetized in the “gilch” route, meanwhile in the material synthesized in the “sulfinyl” route the best expressed traps appear at 0.28 eV.
Photonic crystal coupled cavities with increased beaming and free space coupling efficiency
Authors: Haddadi S. , Yacomotti A. M. , Sagnes I. , Raineri F. , Beaudoin G. , Le Gratiet L. , Levenson J. A.
Published: January 2013

We implement the band-folding approach in coupled photonic crystal L3 (three missing holes) nanocavities and demonstrate a dramatic beaming improvement compatible with high-Q operation. Directional laser effect is achieved. In addition, resonant free-space coupling to the symmetric and anti-symmetric hybrid modes of the photonic molecule is shown. We measure the coupling to each mode as a function of the spatial position of the laser spot, which can be used as a technique to probe the symmetry of coupled cavity modes.
Inductances and attenuation constant for a thin-film superconducting coplanar waveguide resonator
Authors: Clem John R.
Published: January 2013

The geometric, kinetic, and total inductances and the attenuation constant are theoretically analyzed for a thin-film superconducting coplanar waveguide resonator consisting of a current-carrying central conductor, adjacent slots, and ground planes that return the current. The analysis focuses on films of thickness d obeying d<2λ (λ is the London penetration depth), for which the material properties are characterized by the two-dimensional screening length Λ=2λ2/d. Introducing a cut-off procedure that guarantees that the magnitudes of the currents in the central conductor and the ground planes are equal, new and simpler results are obtained for the kinetic inductance and the attenuation constant for small Λ. Exact results for arbitrary Λ are presented for the geometric, kinetic, and total inductances in the limit of tiny slot widths, and approximate results are presented for arbitrary slot widths.
Tunneling resonances in systems without a classical trapping
Authors: Borisov D. , Exner P. , Golovina A.
Published: January 2013

In this paper, we analyze a free quantum particle in a straight Dirichlet waveguide which has at its axis two Dirichlet barriers of lengths ℓ± separated by a window of length 2a. It is known that if the barriers are semi-infinite, i.e., we have two adjacent waveguides coupled laterally through the boundary window, the system has for any a > 0 a finite number of eigenvalues below the essential spectrum threshold. Here, we demonstrate that for large but finite ℓ± the system has resonances which converge to the said eigenvalues as ℓ± → ∞, and derive the leading term in the corresponding asymptotic expansion.
A high-K ferroelectric relaxor terpolymer as a gate dielectric for organic thin film transistors
Authors: Wu Shan , Shao Ming , Burlingame Quinn , Chen Xiangzhong , Lin Minren , Xiao Kai , Zhang Q. M.
Published: January 2013

Poly(vinylidenefluoride-trifluoroethylene-chlorofluoroethylene) (P(VDF-TrFE-CFE)) is a ferroelectric terpolymer relaxor with a static dielectric constant of 50, which was developed using defect modification to eliminate remnant polarization in the normal ferroelectric PVDF. In this work, this solution processable terpolymer was used as the gate insulator in bottom gated organic thin-film transistors with a pentacene semiconductor layer. Due to the high dielectric constant of P(VDF-TrFE-CFE), a large capacitive coupling between the gate and channel can be achieved which causes a high charge concentration at the interface of the semiconductor and dielectric layers. In this device, an on/off ratio of 104 and a low minimum operation gate voltage (5-10 V) were attained.
The flexible nature of exchange, correlation, and Hartree physics: Resolving “delocalization” errors in a “correlation free” density functional
Authors: Gould Tim , Dobson John F.
Published: January 2013

By exploiting freedoms in the definitions of “correlation,” “exchange,” and “Hartree” physics in ensemble systems, we better generalise the notion of “exact exchange” (EXX) to systems with fractional occupations of the frontier orbitals, arising in the dissociation limit of some molecules. We introduce the linear EXX (“LEXX”) theory whose pair distribution and energy are explicitly piecewise linear in the occupations \documentclass[12pt]{minimal}\begin{document}$f^{\sigma }_{i}$\end{document}fiσ. We provide explicit expressions for these functions for frontier s and p shells. Used in an optimised effective potential (OEP) approach the LEXX yields energies bounded by the piecewise linear “ensemble EXX” (EEXX) energy and standard fractional optimised EXX energy: EEEXX ⩽ ELEXX ⩽ EEXX. Analysis of the LEXX explains the success of standard OEP methods for diatoms at large spacing, and why they can fail when both spins are allowed to be non-integer so that “ghost” Hartree interactions appear between opposite spin electrons in the usual formula. The energy ELEXX contains a cancellation term for the spin ghost case. It is evaluated for H, Li, and Na fractional ions with clear derivative discontinuities for all cases. The p-shell form reproduces accurate correlation-free energies of B-F and Al-Cl. We further test LEXX plus correlation energy calculations on fractional ions of C and F and again we find both derivative discontinuities and good agreement with exact results.
Relaxation-time measurement via a time-dependent helicity balance model
Authors: Wrobel J. S. , Hansen C. J. , Jarboe T. R. , Smith R. J. , Hossack A. C. , Nelson B. A. , Marklin G. J. , Ennis D. A. , Akcay C. , Victor B. S.
Published: January 2013

A time-dependent helicity balance model applied to a spheromak helicity-injection experiment enables the measurement of the relaxation time during the sustainment phase of the spheromak. The experiment, the Helicity Injected Torus with Steady Inductive helicity injection (HIT-SI), studies spheromak formation and sustainment through inductive helicity injection. The model captures the dominant plasma behavior seen during helicity injection in HIT-SI by using an empirical helicity-decay rate, a time-dependent helicity-injection rate, and a composite Taylor state to model both the helicity content of the system and to calculate the resulting spheromak current. During single-injector operations, both the amplitude and the phase of the periodic rise and fall of the toroidal current are predicted by this model, with an exchange of helicity between the injector states and the spheromak state proposed as the causal mechanism. This phenomenon allows for the comparison of the delay between the current rises in the experiment and the numerical model, enabling a measurement of the relaxation time. The measured relaxation time of 4.8 μs ± 2.8 μs is shorter than the toroidal Alfvén timescale. These results validate Hall MHD calculations of the Geospace Environmental Modeling challenge.
Enhancement of spin wave excitation by spin currents due to thermal gradient and spin pumping in yttrium iron garnet/Pt
Authors: da Silva G. L. , Vilela-Leão L. H. , Rezende S. M. , Azevedo A.
Published: January 2013

We investigate the interplay between spin currents produced by thermal gradients and spin pumping in hybrid yttrium iron garnet/Pt structures (YIG/Pt). By combining a spin pumping experiment with the application of a temperature gradient, we observe the excitation of local spin wave modes at the YIG/Pt interface. Strong enhancement of these modes was observed when the temperature gradient was applied along one direction and attenuation was observed by reversing the temperature gradient. The results provide support for a recent theoretical proposal, in which some spin wave modes are preferentially excited by spin currents traversing a YIG/Pt interface.
Quantum Hall transport as a probe of capacitance profile at graphene edges
Authors: Vera-Marun I. J. , Zomer P. J. , Veligura A. , Guimarães M. H. D. , Visser L. , Tombros N. , van Elferen H. J. , Zeitler U. , van Wees B. J.
Published: January 2013

The quantum Hall effect is a remarkable manifestation of quantized transport in a two-dimensional electron gas (2DEG). Given its technological relevance, it is important to understand its development in realistic nanoscale devices. In this work, we present how the appearance of different edge channels in a field-effect device is influenced by the inhomogeneous capacitance profile existing near the sample edges, a condition of particular relevance for graphene. We apply this practical idea to experiments on high quality graphene, demonstrating the potential of quantum Hall transport as a spatially resolved probe of density profiles near the edge of this two-dimensional electron gas.
A large volume uniform plasma generator for the experiments of electromagnetic wave propagation in plasma
Authors: Min Yang , Xiaoping Li , Kai Xie , yanming Liu , Donglin Liu
Published: January 2013

A large volume uniform plasma generator is proposed for the experiments of electromagnetic (EM) wave propagation in plasma, to reproduce a “black out” phenomenon with long duration in an environment of the ordinary laboratory. The plasma generator achieves a controllable approximate uniform plasma in volume of 260 mm× 260 mm× 180 mm without the magnetic confinement. The plasma is produced by the glow discharge, and the special discharge structure is built to bring a steady approximate uniform plasma environment in the electromagnetic wave propagation path without any other barriers. In addition, the electron density and luminosity distributions of plasma under different discharge conditions were diagnosed and experimentally investigated. Both the electron density and the plasma uniformity are directly proportional to the input power and in roughly reverse proportion to the gas pressure in the chamber. Furthermore, the experiments of electromagnetic wave propagation in plasma are conducted in this plasma generator. Blackout phenomena at GPS signal are observed under this system and the measured attenuation curve is of reasonable agreement with the theoretical one, which suggests the effectiveness of the proposed method.
Atherosclerotic geometries exacerbate pathological thrombus formation poststenosis in a von Willebrand factor-dependent manner
Authors: Westein Erik , van der Meer Andries D. , Kuijpers Marijke J. E. , Frimat Jean-Philippe , van den Berg Albert , Heemskerk Johan W. M.
Published: January 2013

Rupture of a vulnerable atherosclerotic plaque causes thrombus formation and precipitates cardiovascular diseases. In addition to the thrombogenic content of a plaque, also the hemodynamic microenvironment plays a major role in thrombus formation. How the altered hemodynamics around a plaque promote pathological thrombus formation is not well understood. In this study, we provide evidence that plaque geometries result in fluid mechanical conditions that promote platelet aggregation and thrombus formation by increased accumulation and activity of von Willebrand factor (vWF) at poststenotic sites. Resonant-scanning multiphoton microscopy revealed that in vivo arterial stenosis of a damaged carotid artery markedly increased platelet aggregate formation in the stenotic outlet region. Complementary in vitro studies using microfluidic stenotic chambers, designed to mimic the flow conditions in a stenotic artery, showed enhanced platelet aggregation in the stenotic outlet region at 60–80% channel occlusion over a range of input wall shear rates. The poststenotic thrombus formation was critically dependent on bloodborne vWF and autocrine platelet stimulation. In stenotic chambers containing endothelial cells, flow provoked increased endothelial vWF secretion in the stenotic outlet region, contributing to exacerbated platelet aggregation. Taken together, this study identifies a role for the shear-sensitive protein vWF in transducing hemodynamic forces that are present around a stenosis to a prothrombogenic microenvironment resulting in spatially confined and exacerbated platelet aggregation in the stenosis outlet region. The developed stenotic microfluidic chamber offers a realistic platform for in vitro evaluation of shear-dependent thrombus formation in the setting of atherosclerosis.
Mouse marginal zone B cells harbor specificities similar to human broadly neutralizing HIV antibodies
Authors: Pujanauski Lindsey M. , Janoff Edward N. , McCarter Martin D. , Pelanda Roberta , Torres Raul M.
Published: January 2013

A series of potent, broadly neutralizing HIV antibodies have been isolated from B cells of HIV-infected individuals. VRC01 represents a subset of these antibodies that mediate neutralization with a restricted set ofIGHVgenes. The memory B cells expressing these antibodies were isolated years after infection; thus, the B-cell subpopulation from which they originated and the extent of participation in the initial HIV antibody response, if any, are unclear. Here we evaluated the frequency of anti-gp120 B cells in follicular (FO) and marginal zone (MZ) B-cell compartments of naïve WT mice and comparable human populations in uninfected individuals. We found that in non–HIV-exposed humans and mice, the majority of gp120-reactive B cells are of naïve and FO phenotype, respectively. Murine FO B cells express a diverse antibody repertoire to recognize gp120. In contrast, mouse MZ B cells recognize gp120 less frequently but preferentially useIGHV1-53to encode gp120-specific antibodies. Notably,IGHV1-53shows high identity to humanIGHV1-2*02, which has been repeatedly found to encode broadly neutralizing mutated HIV antibodies, such as VRC01. Finally, we show that human MZ-like B cells expressIGHV1-2*02, and thatIGHV1-53expression is enriched in mouse MZ B cells. These data suggest that efforts toward developing an HIV vaccine might consider eliciting protective HIV antibody responses selectively from alternative B-cell populations harboringIGHVgene segments capable of producing protective antibodies.
Novel techniques for preserving genetic diversity in poultry germplasm.
Authors: Silversides F. G. , Liu JianAn Liu JianAn
Published: January 2013

There have been massive losses of avian genetic material over the past several decades, partly because of a belief that cryoconservation techniques used for mammals do not work for birds. For several avian species, cryopreservation of semen may not be sufficiently efficient to use in commercial practice but the fertility it produces is fully adequate for conservation purposes. Technology around embryonic primordial germ cells, which will produce the gametes, has been used to produce transgenic birds. These cells can be isolated, cryopreserved and recovered in chimaeras but the efficiency of recovery is far too low for conservation purposes because several dozen individuals must be produced to recover the variation from the original population. Cryopreservation of avian gonads with subsequent recovery of the germline through transplantation has been demonstrated recently and should provide the ability to both cryoconserve and recover avian populations.
Ablation of cardiac myosin–binding protein-C accelerates contractile kinetics in engineered cardiac tissue
Authors: de Lange Willem J. , Grimes Adrian C. , Hegge Laura F. , Ralphe J. Carter
Published: December 2012

Hypertrophic cardiomyopathy (HCM) caused by mutations in cardiac myosin–binding protein-C (cMyBP-C) is a heterogenous disease in which the phenotypic presentation is influenced by genetic, environmental, and developmental factors. Though mouse models have been used extensively to study the contractile effects of cMyBP-C ablation, early postnatal hypertrophic and dilatory remodeling may overshadow primary contractile defects. The use of a murine engineered cardiac tissue (mECT) model of cMyBP-C ablation in the present study permits delineation of the primary contractile kinetic abnormalities in an intact tissue model under mechanical loading conditions in the absence of confounding remodeling events. We generated mechanically integrated mECT using isolated postnatal day 1 mouse cardiac cells from both wild-type (WT) and cMyBP-C–null hearts. After culturing for 1 wk to establish coordinated spontaneous contraction, we measured twitch force and Ca2+ transients at 37°C during pacing at 6 and 9 Hz, with and without dobutamine. Compared with WT, the cMyBP-C–null mECT demonstrated faster late contraction kinetics and significantly faster early relaxation kinetics with no difference in Ca2+ transient kinetics. Strikingly, the ability of cMyBP-C–null mECT to increase contractile kinetics in response to adrenergic stimulation and increased pacing frequency were severely impaired. We conclude that cMyBP-C ablation results in constitutively accelerated contractile kinetics with preserved peak force with minimal contractile kinetic reserve. These functional abnormalities precede the development of the hypertrophic phenotype and do not result from alterations in Ca2+ transient kinetics, suggesting that alterations in contractile velocity may serve as the primary functional trigger for the development of hypertrophy in this model of HCM. Our findings strongly support a mechanism in which cMyBP-C functions as a physiological brake on contraction by positioning myosin heads away from the thin filament, a constraint which is removed upon adrenergic stimulation or cMyBP-C ablation.
Looking into the Future: A Match between Self-View and Temporal Distance
Authors: Spassova Gerri , Lee Angela Y.
Published: January 2013

Representing an event in abstract (vs. concrete) terms and as happening in the distant (vs. proximal) future has been shown to have important consequences for cognition and motivation. Less is known about factors that influence construal level and perceived temporal distance. The present research identifies one such factor and explores the implications for persuasion. Four studies show that an independent self-view is associated with abstract representations of future events and with perceiving these events as happening in the more distant future, whereas an interdependent self-view is associated with concrete representations of future events and with perceiving these events as happening in the more proximal future. Furthermore, a match (vs. mismatch) between the temporal frame of an advertisement and the self-view of the recipient leads to systematic changes in advertisement effectiveness and product appeal. These results add to the construal level theory and the self literatures and have practical implications for advertisers.
Thirty trends shaping the future of academic libraries
Authors: ATTIS David , KOPROSKE Colin
Published: December 2012

This collection of observations, insights, and strategies summarizes the findings from the Education Advisory Board's 2011 research initiative, ‘Redefining the Academic Library: Managing the Migration to Digital Information Services‘, which was conducted on behalf of its membership of over 200 provosts and vice‐presidents for academic affairs at institutions across North America. The full report is freely accessible at http://www.educationadvisoryboard.com/pdf/23634‐EAB‐Redefining‐the‐Academic‐Library.pdf
How authors can maximise the chance of manuscript acceptance and article visibility
Authors: KALWIJ Jesse M. , SMIT Christian
Published: December 2012

The current peer‐review system is being overloaded with manuscript submissions that increasingly exceed reviewer availability and journal publication space. Consequently manuscript rejections rates, peer‐review requests, and subject‐editors' workloads are mounting. Here we outline common problems with manuscript submissions and propose solutions that are both straightforward and easy to implement. We suggest that authors themselves can do much more to relieve the overloaded peer‐review system, while simultaneously increasing their own manuscript acceptance rate and article visibility.
Disorders of The Epidermis: Differentiation and Kinetics
Authors: Sybert Virginia P.
Published: January 2013

Ichthyoses – Bullous Congenital Ichthyosiform Erythroderma – Continual Peeling Skin – Harlequin Fetus – Ichthyosis Bullosa of Siemens – Ichthyosis Hystrix – Ichthyosis Vulgaris – Lamellar Exfoliation of the Newborn – Lamellar Ichthyosis/Nonbullous Congenital Ichthyosiform Erythroderma – Netherton Syndrome – Restrictive Dermopathy – X-linked Recessive Ichthyosis – Erythrokeratodermas – Erythrokeratodermia Variabilis – Pityriasis Rubra Pilaris – Progressive Symmetric Erythrokeratoderma – Acrokeratoderma – Acrokeratoelastoidosis – Acrokeratosis Verruciformis (HOPF) – Hereditary Palmoplantar Keratodermas – Hereditary Palmoplantar Keratoderma with Deafness – Hereditary Palmoplantar Keratoderma Epidermolytic Hyperkeratosis – Hereditary Palmoplantar Keratoderma Howel-Evans – Hereditary Palmoplantar Keratoderma Olmsted – Hereditary Palmoplantar Keratoderma Punctate – Hereditary Palmoplantar Keratoderma Striata – Hereditary Palmoplantar Keratoderma Unna-Thost – Hereditary Palmoplantar Keratoderma Vohwinkel – Keratolytic Winter Erythema – Mal de Meleda – Papillon-Lefèvre – Scleroatrophic and Keratotic Dermatosis of the Limbs – Porokeratoses – Porokeratosis of Mibelli – Other Disorders of the Epidermis – Absence of Dermatoglyphics – Acanthosis Nigricans – Darier-White Disease – Hereditary Painful Callosities – Keratosis Follicularis Spinulosa Decalvans – Knuckle Pads – Kyrle/Flegel Disease – Ulerythema Ophryogenes – Syndromic Disorders – CHILD Syndrome – Chondrodysplasia Punctata – Ichthyosis with Hypogonadism – KID Syndrome – Neu-Laxova Syndrome – Neutral Lipid Storage Disease with Ichthyosis – Refsum Disease – Richner-Hanhart Syndrome – Sjögren-Larsson Syndrome – Cohesion – Epidermolysis Bullosa – Epidermolysis Bullosa Simplex Dowling-Meara – Epidermolysis Bullosa Simplex Generalized – Epidermolysis Bullosa Simplex Localized – Epidermolysis Bullosa Junctional Generalized – Epidermolysis Bullosa Junctional Generalized Atrophic Benign – Epidermolysis Bullosa Dystrophica Cockayne-Touraine – Epidermolysis Bullosa Dystrophica, Hallopeau-Siemens – Epidermolysis Bullosa Dystrophica Pretibial – Transient Bullous Dermolysis of the Newborn – Hailey-Hailey Disease
Disorders of Epidermal Appendages
Authors: Sybert Virginia P.
Published: January 2013

Hair – Alopecias – Loose Anagen Hair – Male Pattern Baldness – Marie Unna Syndrome – Hirsutism – Gingival Fibromatosis and Hypertrichosis – Hypertrichosis Lanuginosa Congenita – Leprechaunism – Localized Hypertrichosis – Polycystic Ovarian Disease – Hair Shaft Abnormalities, Isolated – Monilethrix – Pili Annulati – Pili Torti – Pili Trianguli Et Canaliculi – Trichorrhexis Invaginata – Trichorrhexis Nodosa – Woolly Hair – Hair Shaft Abnormalities, Syndromic – Menkes Disease – Trichodentoosseous Syndrome – Trichorhinophalangeal Syndrome – Trichothiodystrophy – Nails – Nail Disorders, Isolated – Congenital Malalignment of the Great Toenails – Familial Dystrophic Shedding of the Nails – Leukonychia – Twenty-Nail Dystrophy – Nail Disorders, Syndromic – Nail-Patella Syndrome – Onychotrichodysplasia and Neutropenia – Pachyonychia Congenita – Sweat Glands – Hidradenitis Suppurativa – Hyperhidrosis – Multiple Syringomas – Sebaceous Glands – Eruptive Vellus Hair Cysts – Familial Dyskeratotic Comedones – Oral-Facial-Digital Syndrome Type I – Steatocystoma Multiplex – Ectodermal Dysplasia Syndromes – AEC Syndrome – Clouston Syndrome – EEC Syndrome – Focal Facial Ectodermal Dysplasia – GAPO Syndrome – Hypohidrotic Ectodermal Dysplasia – Tooth and Nail Syndrome
Lymphedema
Authors: Sybert Virginia P.
Published: January 2013

Cholestasis-Lymphedema Syndrome – Distichiasis and Lymphedema – Hereditary Lymphedema
Tumors/Hamartomas
Authors: Sybert Virginia P.
Published: January 2013

Basal Cell Nevus Syndrome – Bathing Trunk Nevus – Cowden Disease – Cylindromatosis – Dysplastic Nevus Syndrome – Epidermal Nevus – Gardner Syndrome – Hereditary Keratoacanthomas – Infantile Myofibromatosis – Multiple Endocrine Neoplasia Types 1, 2A, and 2B/3 – Multiple Leiomyomatosis – Pilomatricoma – Proteus Syndrome – Sebaceous Nevus Syndrome – Tumoral Calcinosis
Metabolic Disease
Authors: Sybert Virginia P.
Published: January 2013

Porphyrias – Congenital Erythropoietic Porphyria – Erythropoietic Protoporphyria – Hereditary Coproporphyria – Porphyria Cutanea Tarda – Variegate Porphyria – Mucopolysaccharidoses – Hunter Syndrome – Other Metabolic Disorders – Acrodermatitis Enteropathica – Alkaptonuria – Biotinidase Deficiency – Familial Cutaneous Amyloidosis – Prolidase Deficiency
Breast and endocrine surgery
Authors: Gardiner Matthew D. , Borley Neil R.
Published: January 2013

This chapter begins by discussing the basic principles of oncology, cancer diagnosis and classification, and cancer treatment, before focusing on the key areas of knowledge, namely disorders of breast development and involution, breast cancer assessment and management, goitre, altered thyroid state, thyroid cancer, parathyroid conditions, adrenal conditions, and multiple endocrine neoplasia. The chapter concludes with relevant case-based discussions.
Colorectal surgery
Authors: Gardiner Matthew D. , Borley Neil R.
Published: January 2013

This chapter begins by discussing the basic principles of gastrointestinal embryology, gastrointestinal anatomy, and intestinal stomas,before focusing on the key areas of knowledge, namely abdominal wall hernias, Crohn’s disease, ulcerative colitis, diverticular disease, colorectal polyps, colorectal cancer, haemorrhoids, fissure in ano, perianal infection and fistula-in-ano, and other anorectal conditions. The chapter concludes with relevant case-based discussions.
Neurosurgery
Authors: Gardiner Matthew D. , Borley Neil R.
Published: January 2013

This chapter begins by discussing the basic principles of neuroscience intensive care and neurological rehabilitation and neuropsychology, before focusing on the key areas of knowledge, namely chronic subdural haematoma, subarachnoid haemorrhage, hydrocephalus, intracranial tumours, intracranial and spinal infections, and degenerative spinal conditions. The chapter concludes with relevant case-based discussions.
Otolaryngology and head and neck surgery
Authors: Gardiner Matthew D. , Borley Neil R.
Published: January 2013

This chapter begins by discussing the basic principles of audiology, before focusing on the key areas of knowledge, namely hearing loss, benign labyrinth conditions and disorders of equilibrium, otitis media, chronic suppurative otitis media, external ear, epistaxis, nasal conditions, snoring, and sleep apnoea, childhood airway conditions, adenoids and tonsils, paranasal sinuses, salivary glands, neck lumps, laryngeal cancer, oropharyngeal, nasal, and nasopharyngeal cancer, facial palsy, and acute red eye. The chapter concludes with relevant case-based discussions.
Paediatric surgery
Authors: Gardiner Matthew D. , Borley Neil R.
Published: January 2013

This chapter begins by discussing the basic principles of paediatric anatomy and physiology and paediatric abdominal pain before focusing on the key areas of knowledge, namely congenital abdominal wall defects, anorectal malformations, miscellaneous neonatal conditions, infantile hypertrophic pyloric stenosis, intussusception, penile conditions, testicular torsion, epididymitis and orchitis, infantile inguinal hernia and hydrocele, and testicular maldescent. The chapter concludes with relevant case-based discussions.
Nonalcoholic steatohepatitis
Authors: Stewart Stephen F. , Day Chris P.
Published: January 2013

Nonalcoholic fatty liver disease (NAFLD) is the most common liver disorder in the developed world, affecting 20 to 30% of Western adults. Nonalcoholic liver disease occurs with a range of severity from simple steatosis through nonalcoholic steatohepatitis (NASH) to fatty fibrosis—and, ultimately, cirrhosis. The condition is a manifestation of the metabolic syndrome, strongly associated with obesity, insulin resistance, and dyslipidaemia; dietary and genetic factors appear to determine susceptibility to the disease and its progression....
Acute pancreatitis
Authors: Carter R. , McKay C.J.
Published: January 2013

Acute pancreatitis affects 300 to 600 new patients per million population per year and is most commonly caused by gallstones or alcohol, but there are many other causes and associations. Careful imaging reveals that most so-called idiopathic acute pancreatitis is due to small (1–3 mm diameter) gallstones. Diagnosis is made by a combination of a typical presentation (upper abdominal pain and vomiting) in conjunction with raised serum amylase (> × 3 upper limit of normal) and/or lipase (> × 2 upper limit of normal). Several acute abdominal emergencies can mimic acute pancreatitis and may be associated with a raised serum amylase. These include perforated peptic ulcer (particularly perforated posterior gastric ulcer) and acute mesenteric ischaemia. In equivocal cases, a CT scan is indicated in order to exclude other causes and confirm the diagnosis....
Epilepsy in later childhood and adulthood
Authors: Perkin G.D. , Johnson M.R.
Published: January 2013

Case History—A 33 yr old woman, known to have epilepsy, now presenting with odd behaviour.

An epileptic seizure is a transient occurrence of signs and/or symptoms due to abnormal excessive or synchronous neuronal activity in the brain. Epilepsy is defined as a disorder of the brain characterized by an enduring predisposition to generate epileptic seizures and by the neurobiological, cognitive, psychological, and social consequences of this condition. The definition of epilepsy requires the occurrence of at least one epileptic seizure and evidence for an enduring alteration in the brain that increases the likelihood of future seizures such as an ‘epileptiform’ EEG abnormality, an appropriate lesion on structural brain imaging (CT or MRI), or the presence of recurrent (two or more) seizures. Epilepsy is a common, serious neurological disease, with prevalence 1% and a cumulative lifetime risk of 5%....
Narcolepsy
Authors: Parkes David
Published: January 2013

Narcolepsy is the specific syndrome of daytime sleepiness with cataplexy, where there is a sudden loss of muscle tone—often provoked by the anticipation of emotions—leading to a tendency to fall, mouth opening, dysarthria or mutism, and facial muscle jerking. It is associated with loss of hypocretin (orexin) neurons in the hypothalamus, hypocretin-1 concentrations in the cerebrospinal fluid below 100 ng/litre, and the HLA genotype DQ B1*0602. Once established, narcolepsy is lifelong; spontaneous recovery does not occur. Treatment—which is essential to restore school performance, work, driving ability and quality of life—is with stimulant (e.g. amphetamine) and anticataplectic (e.g. clomipramine) drugs, supported by a 15-min nap once or twice a day....
Diseases of the spinal cord
Authors: Larner A.J.
Published: January 2013

Case History—An 81 yr old man presenting with difficulty walking, paraesthiesiae in his feet, and urinary symptoms.

The spinal cord is subject to numerous pathological processes that can arise within (intramedullary) and/or extrinsic to the cord (extramedullary lesions).

Symptoms and signs suggestive of spinal cord disease include (1) motor—weakness and alteration in tone; acute cord lesions produce flaccidity (‘spinal shock’) and chronic processes spasticity, with hyper-reflexia, clonus, and upgoing plantar responses; pathological processes targeting lower motor neurons in the anterior horns typically produce early muscle wasting and fasciculation; (2) sensory—including numbness, loss of sensation, tingling, sensory ataxia; the demonstration of a sensory level and analysis of specific sensory deficit patterns are of particular importance in localizing the site, and therefore the likely cause, of any lesion; and (3) autonomic—sphincter dysfunction, most commonly affecting bladder function....
Autoimmune limbic encephalitis and Morvan’s syndrome
Authors: Buckle Camilla , Vincent Angela
Published: January 2013

Autoimmune limbic encephalitis—typical presentation is with acute or subacute onset of short term memory loss, seizures and disorientation. MRI characteristically shows striking abnormalities in the hippocampus. Antibodies against cell-surface proteins that are components of voltage-gated potassium channel (VGKC) complexes are found in a high proportion and are probably pathogenic. Aside from supportive care, treatment is with immunosuppression, often comprising corticosteroids with intravenous immunoglobulin and/or plasma exchange....
Severe headache of sudden onset
Authors: Kernick David , Goadsby Peter J.
Published: January 2013

This chapter covers subarachnoid haemorrhage, central venous thrombosis (CVT), cervical arterial dissection, reversible segmental vasoconstriction syndrome (RSVS), spontaneous intracranial hypotension, and pituitary apoplexy.
Tension-type headache
Authors: Kernick David , Goadsby Peter J.
Published: January 2013

This chapter begins with an introduction to tension-type headache, before covering clinical features, differential diagnosis, pathophysiology, and treatment.
Headache associated with exertion, cough and sex
Authors: Kernick David , Goadsby Peter J.
Published: January 2013

This chapter covers the mechanism of exertional headache, cough headache, physical exertion headache, and headache associated with sexual activity.
Headache in children
Authors: Kernick David , Goadsby Peter J.
Published: January 2013

This chapter covers headache in children, focusing first on secondary headache and then primary headache.
External eye disease
Authors: Goyal Saurabh , Barsam Allon , Tuft Stephen
Published: January 2013

This chapter covers corneal and conjunctival basic science, before covering clinical skills (history taking for anterior segment disease and examination of the anterior segment). The chapter then covers blepharitis, staphylococcal hypersensitivity disorders, dry eye disease, conjunctivitis, cicatrizing conjunctival disease, conjunctival degeneration, conjunctival neoplasia, corneal degeneration, infectious keratitis, interstitial keratitis, peripheral ulcerative keratitis, metabolic and drug-induced keratopathies, corneal dystrophies, contact lenses, corneal ectasia, keratoplasty, complications of keratoplasty and graft rejection, anterior uveal tumours, anterior segment trauma, chemical injury, and refractive surgery. Practical skills are then covered, including corneal glue, removal of corneal sutures, removal of corneal foreign bodies, corneal topography, and corneal pachymetry. The chapter concludes with three case-based discussions, on chemical injury, Herpes zoster keratitis, and bacterial keratitis.
Oculoplastics
Authors: Barsam Allon , Uddin Jimmy
Published: January 2013

This chapter begins by looking at the eyelid and nasolacrimal system anatomy, before covering the key areas of clinical knowledge, namely lash abnormality, entropion, ectropion, ptosis, benign lid lesions, premalignant and malignant lid lesions, epiphora, acquired nasolacrimal system abnormalities, and congenital abnormalities. Clinical and practical skills are then covered, including ptosis examination, evaluation of the patient with acquired epiphora, incision and curettage of chalazion, syringing and probing, and botulinum-toxin injections. The chapter concludes with three case-based discussions, on epiphora, ptosis, and lid lump.