bluuebunny/crossref_metadata_2025 huggingface dataset:
Preparation of biocompatible and antibacterial carbon quantum dots derived from resorcinol and formaldehyde spheres
Authors: Roy Arup Kumer , Kim Sung-Min , Paoprasert Peerasak , Park Sung-Young , In Insik
Published: March 2015

Green or yellow emitting carbon quantum dots (CQDs) were prepared through the combination of bottom-up and top-down approaches from resorcinol and formaldehyde.
Luciferase gene-loaded CS-Qdots as self-illuminating probes for specific hepatoma imaging
Authors: Yuan Chenyan , Wang Ling , An Yanli , Wu Guoqiu , Zhang Dongsheng
Published: March 2015

Luciferase gene-loaded chitosan encapsulated quantum dots (CS-Qdots) can act as wavelength-tunable self-illuminating probes thus holding potential for improved tumor optical molecular imaging.
Plasmon-enhanced light harvesting: applications in enhanced photocatalysis, photodynamic therapy and photovoltaics
Authors: Zhou Na , López-Puente Vanesa , Wang Qing , Polavarapu Lakshminarayana , Pastoriza-Santos Isabel , Xu Qing-Hua
Published: March 2015

This review article summarizes the recent progress on surface plasmon-enhanced light harvesting and its applications toward enhanced photocatalysis, photodynamic therapy, chemical transformations and photovoltaics.
Effects of the surface modification of carbon fiber by growing different types of carbon nanomaterials on the mechanical and thermal properties of polypropylene
Authors: Ghaemi F. , Yunus R. , Salleh M. A. M. , Rashid S. A. , Ahmadian A. , Lim H. N.
Published: March 2015

The potential usage of different types of carbon nanomaterials such as carbon nanofiber (CNF), carbon nanotube (CNT) and graphene (G) flake and also CNF–G and CNT–G on the carbon fiber (CF) surface as fillers in composites, is discussed in this paper.
Influence of n-octanol in mobile phase on QSRRs of lipophilicity and retention mechanism of acidic and basic compounds in RP-HPLC
Authors: Han Shu-ying , Liang Chao , Yu Hui-min , Qiao Jun-qin , Ge Xin , Lian Hong-zhen
Published: March 2015

Effect ofn-octanol on retention behavior, mechanism and QSRRs of ionizable compounds in RP-HPLC.
Roughness controlled superhydrophobicity on single nanometer length scale with metal nanoparticles
Authors: ten Brink Gert H. , Foley Nolan , Zwaan Darin , Kooi Bart J. , Palasantzas George
Published: March 2015

Here we demonstrate water droplet pinning onto nanostructured surfaces via control of roughness on a single nanometer length-scale generated by deposition of preformed gas phase distinct copper nanoparticles on hydrophilic and hydrophobic surfaces.
Dissection of the binding ofl-ascorbic acid to trypsin and pepsin using isothermal titration calorimetry, equilibrium microdialysis and spectrofluorimetry
Authors: Li Xiangrong , Yang Zhijun
Published: March 2015

Clear and quantitative information on the nature ofl-ascorbic acid interaction with trypsin/pepsin should provide a firm base for its rational use in clinical practice.
One-pot conversion of cellobiose to mannose using a hybrid phosphotungstic acid–cerium oxide catalyst
Authors: Gernhart Zane C. , Bhalkikar Anuja , Burke John J. , Sonnenfeld Kate O. , Marin Chris M. , Zbasnik Richard , Cheung Chin Li
Published: March 2015

Two-step conversion of cellobiose to mannose using hybrid catalyst.
Porous graphene–carbon nanotube hybrid paper as a flexible nano-scaffold for polyaniline immobilization and application in all-solid-state supercapacitors
Authors: Fan Wei , Miao Yue-E , Zhang Longsheng , Huang Yunpeng , Liu Tianxi
Published: March 2015

Three-dimensional porous graphene–carbon nanotube hybrid papers were obtained as a conductive, flexible and free-standing nano-scaffold for PANI immobilization.
Surface plasmon-enhanced dye-sensitized solar cells based on double-layered composite films consisting of TiO2/Ag and TiO2/Au nanoparticles
Authors: Kim Hyun-Young , Song Da Hyun , Yoon Hyeokjin , Suh Jung Sang
Published: March 2015

Double-layered composite films consisting of TiO2/Ag and TiO2/Au nanoparticles.
Depth-reduction induced low onset potential of hematite photoanodes for solar water oxidation
Authors: Hao Yuanyuan , Deng Jiujun , Zhou Litao , Sun Xuhui , Zhong Jun
Published: March 2015

The pressure-induced depth-reduction of hematite in a crucible results in a cathodic shift of the onset potential by 70 mV.
Slow magnetic relaxation in a novel carboxylate/oxalate/hydroxyl bridged dysprosium layer
Authors: Yin Dan-Dan , Chen Qi , Meng Yin-Shan , Sun Hao-Ling , Zhang Yi-Quan , Gao Song
Published: March 2015

2D dysprosium complex exhibiting slow magnetic relaxation originating from the strong Ising anisotropy of single Dy3+ ions has been reported.
Probing the vibrational spectroscopy of the deprotonated thymine radical by photodetachment and state-selective autodetachment photoelectron spectroscopy via dipole-bound states
Authors: Huang Dao-Ling , Liu Hong-Tao , Ning Chuan-Gang , Zhu Guo-Zhu , Wang Lai-Sheng
Published: March 2015

High-resolution state-selective autodetachment photoelectron spectroscopy via dipole-bound states and photodetachment spectroscopy of cryogenically cooled deprotonated thymine anions are reported.
One-step synthesis of SnOx nanocrystalline aggregates encapsulated by amorphous TiO2 as an anode in Li-ion battery
Authors: Hou Xiaoyu , Hu Yanjie , Jiang Hao , Li Yunfeng , Li Wenge , Li Chunzhong
Published: March 2015

SnOx nanocrystalline aggregates (NAs) encapsulated by an amorphous TiO2 layer have been successfully designed by a one-step flame spray pyrolysis (FSP) method. As an anode in LIBs, the SnOx NAs@TiO2 electrode exhibits a capacity of 350 mA h g−1 after 300 cycles at a current density of 200 mA g−1, which is much superior to pure SnOx NAs and TiO2 NAs.
Charging behavior of carbon black in a low-permittivity medium based on acid–base charging theory
Authors: Liu Hongli , Wang Shirong , Xiao Yin , Yang Quanhong , Li Xianggao
Published: March 2015

Carbon black nanoparticles obtained an impressive high zeta potential of −180.3 mV in a nonpolar medium with the addition of T151.
Stacking fault and unoccupied densities of state dependence of electromagnetic wave absorption in SiC nanowires
Authors: Zhang Hangyu , Xu Yongjun , Zhou Jigang , Jiao Jinfu , Chen Yujin , Wang Huan , Liu Chenyu , Jiang Zhaohua , Wang Zhijiang
Published: March 2015

SiC nanowires with a higher carbon unoccupied DOS possess more stacking faults, resulting in extensive energy dissipation under electromagnetic radiation.
Bio-inspired thermal-responsive inverse opal films with dual structural colors based on liquid crystal elastomer
Authors: Xing Huihui , Li Jun , Guo Jinbao , Wei Jie
Published: March 2015

The fabrication of inverse opal micropatterns based on liquid crystal elastomers with dual structural colors and their thermal switching behaviors are described.
Reconfiguring photonic metamaterials with currents and magnetic fields
Authors: Valente João , Ou Jun-Yu , Plum Eric , Youngs Ian J. , Zheludev Nikolay I.
Published: March 2015

We demonstrate that spatial arrangement and optical properties of metamaterial nanostructures can be controlled dynamically using currents and magnetic fields. Mechanical deformation of metamaterial arrays is driven by both resistive heating of bimorph nanostructures and the Lorentz force that acts on charges moving in a magnetic field. With electrically controlled transmission changes of up to 50% at sub-mW power levels, our approaches offer high contrast solutions for dynamic control of metamaterial functionalities in optoelectronic devices.
The effect of in-plane arterial curvature on blood flow and oxygen transport in arterio-venous fistulae
Authors: Iori F. , Grechy L. , Corbett R. W. , Gedroyc W. , Duncan N. , Caro C. G. , Vincent P. E.
Published: March 2015

Arterio-Venous Fistulae (AVF) are the preferred method of vascular access for patients with end stage renal disease who need hemodialysis. In this study, simulations of blood flow and oxygen transport were undertaken in various idealized AVF configurations. The objective of the study was to understand how arterial curvature affects blood flow and oxygen transport patterns within AVF, with a focus on how curvature alters metrics known to correlate with vascular pathology such as Intimal Hyperplasia (IH). If one subscribes to the hypothesis that unsteady flow causes IH within AVF, then the results suggest that in order to avoid IH, AVF should be formed via a vein graft onto the outer-curvature of a curved artery. However, if one subscribes to the hypothesis that low wall shear stress and/or low lumen-to-wall oxygen flux (leading to wall hypoxia) cause IH within AVF, then the results suggest that in order to avoid IH, AVF should be formed via a vein graft onto a straight artery, or the inner-curvature of a curved artery. We note that the recommendations are incompatible—highlighting the importance of ascertaining the exact mechanisms underlying development of IH in AVF. Nonetheless, the results clearly illustrate the important role played by arterial curvature in determining AVF hemodynamics, which to our knowledge has been overlooked in all previous studies.
Dissociative recombination and mutual neutralization of heavier molecular ions: C10H8+, WF5+, and CnFm+
Authors: Wiens Justin P. , Shuman Nicholas S. , Viggiano Albert A.
Published: March 2015

Dissociative recombination (DR) rate coefficients for the naphthalene cation, C10H8+, and WF5+, and mutual neutralization (MN) rate coefficients for these species and five CnFm+ ions, were determined at 300 K using variable electron and neutral density attachment mass spectrometry (VENDAMS). DR proceeds at 9 ± 3 × 10−7 cm3 s−1 for C10H8+ and at 6.1 ± 1.4 × 10−7 cm3 s−1 for WF5+. Consistent with previous results, MN for the polyatomic cations with the halide anions Cl−, Br−, and I− exhibits an approximate μ−1/2 reduced mass dependence of the reactant partners, demonstrating that ion collision velocities influence the rate coefficients. This work is an extension of VENDAMS to systems, where low reactant concentrations are necessary to avoid significant reaction of product ions with the neutral precursor, i.e., conditions not suitable for traditional flowing afterglow measurements, as well as to ions of masses > ∼ 100 Da, which are not amenable to the study of DR in magnetic storage rings. Our results expand the sparse literature on DR and MN of heavier ions.
The Coulomb, exchange, and correlation components of the electron-electron repulsion in harmonium atoms
Authors: Cioslowski Jerzy
Published: March 2015

Highly accurate Coulomb, exchange, and correlation components of the electron-electron repulsion energies of the three-electron harmonium atoms in the 2P− and 4P+ states are obtained for 19 values of the confinement strength ω ranging from 10−3 to 103. The computed data are consistent with their ω → 0 and ω → ∞ asymptotics that are given by closed-form algebraic expressions. Robust approximants that accurately reproduce the actual values of the energy components while strictly conforming to these limits are constructed, opening an avenue to stringent tests capable of predicting the performance of electronic structure methods for systems with varying extents of the dynamical and nondynamical electron correlation. The values of the correlation components, paired with the computed 1-matrices are expected to be particularly useful in the context of benchmarking of approximate density matrix functionals.
Compressible turbulent channel flow with impedance boundary conditions
Authors: Scalo Carlo , Bodart Julien , Lele Sanjiva K.
Published: March 2015

We have performed large-eddy simulations of isothermal-wall compressible turbulent channel flow with linear acoustic impedance boundary conditions (IBCs) for the wall-normal velocity component and no-slip conditions for the tangential velocity components. Three bulk Mach numbers, Mb = 0.05, 0.2, 0.5, with a fixed bulk Reynolds number, Reb = 6900, have been investigated. For each Mb, nine different combinations of IBC settings were tested, in addition to a reference case with impermeable walls, resulting in a total of 30 simulations. The adopted numerical coupling strategy allows for a spatially and temporally consistent imposition of physically realizable IBCs in a fully explicit compressible Navier-Stokes solver. The IBCs are formulated in the time domain according to Fung and Ju [“Time-domain impedance boundary conditions for computational acoustics and aeroacoustics,” Int. J. Comput. Fluid Dyn. 18(6), 503–511 (2004)]. The impedance adopted is a three-parameter damped Helmholtz oscillator with resonant angular frequency, ωr, tuned to the characteristic time scale of the large energy-containing eddies. The tuning condition, which reads ωr = 2πMb (normalized with the speed of sound and channel half-width), reduces the IBCs’ free parameters to two: the damping ratio, ζ, and the resistance, R, which have been varied independently with values, ζ = 0.5, 0.7, 0.9, and R = 0.01, 0.10, 1.00, for each Mb. The application of the tuned IBCs results in a drag increase up to 300% for Mb = 0.5 and R = 0.01. It is shown that for tuned IBCs, the resistance, R, acts as the inverse of the wall-permeability and that varying the damping ratio, ζ, has a secondary effect on the flow response. Typical buffer-layer turbulent structures are completely suppressed by the application of tuned IBCs. A new resonance buffer layer is established characterized by large spanwise-coherent Kelvin-Helmholtz rollers, with a well-defined streamwise wavelength λx, traveling downstream with advection velocity cx = λx Mb. They are the effect of intense hydro-acoustic instabilities resulting from the interaction of high-amplitude wall-normal wave propagation (at the tuned frequency fr = ωr/2π = Mb) with the background mean velocity gradient. The resonance buffer layer is confined near the wall by structurally unaltered outer-layer turbulence. Results suggest that the application of hydrodynamically tuned resonant porous surfaces can be effectively employed in achieving flow control.
Nanocrystalline Fe88−2xCoxNixZr7B4Cu1 alloys: Soft magnets for vehicle electrification technologies (invited)
Authors: Knipling K. E. , Daniil M. , Willard M. A.
Published: March 2015

We report on the effect of substituting Co and Ni for Fe on the crystallization behavior, crystal structure, and magnetic properties of Fe88−2xCoxNixZr7B4Cu1 (x = 0–22.00). The magnetization generally decreases and the coercivity increases with increasing x, whereas the Curie temperature of the amorphous phase increases significantly (from 73 °C at x = 0 to 570 °C at x = 22.00). There is thus an optimum composition near x = 5.50 exhibiting excellent soft magnetic properties at 300–500 °C. The higher magnetization and Curie temperature as compared with Fe-based alloys, and smaller Co content as compared with (Fe,Co)-based alloys, make this alloy attractive as an affordable high-temperature soft magnetic material.
Theoretical and numerical investigations of inverse patchy colloids in the fluid phase
Authors: Kalyuzhnyi Yurij V. , Bianchi Emanuela , Ferrari Silvano , Kahl Gerhard
Published: March 2015

We investigate the structural and thermodynamic properties of a new class of patchy colloids, referred to as inverse patchy colloids (IPCs) in their fluid phase via both theoretical methods and simulations. IPCs are nano- or micro- meter sized particles with differently charged surface regions. We extend conventional integral equation schemes to this particular class of systems: our approach is based on the so-called multi-density Ornstein-Zernike equation, supplemented with the associative Percus-Yevick approximation (APY). To validate the accuracy of our framework, we compare the obtained results with data extracted from NpT and NVT Monte Carlo simulations. In addition, other theoretical approaches are used to calculate the properties of the system: the reference hypernetted-chain (RHNC) method and the Barker-Henderson thermodynamic perturbation theory. Both APY and RHNC frameworks provide accurate predictions for the pair distribution functions: APY results are in slightly better agreement with MC data, in particular at lower temperatures where the RHNC solution does not converge.
An analytical study of double bend achromat lattice
Authors: Fakhri Ali Akbar , Kant Pradeep , Singh Gurnam , Ghodke A. D.
Published: March 2015

In a double bend achromat, Chasman-Green (CG) lattice represents the basic structure for low emittance synchrotron radiation sources. In the basic structure of CG lattice single focussing quadrupole (QF) magnet is used to form an achromat. In this paper, this CG lattice is discussed and an analytical relation is presented, showing the limitation of basic CG lattice to provide the theoretical minimum beam emittance in achromatic condition. To satisfy theoretical minimum beam emittance parameters, achromat having two, three, and four quadrupole structures is presented. In this structure, different arrangements of QF and defocusing quadruple (QD) are used. An analytical approach assuming quadrupoles as thin lenses has been followed for studying these structures. A study of Indus-2 lattice in which QF-QD-QF configuration in the achromat part has been adopted is also presented.
A modified model for thermal conductivity of carbon nanotube-nanofluids
Authors: Thang Bui Hung , Khoi Phan Hong , Minh Phan Ngoc
Published: March 2015

Carbon nanotubes (CNTs) are one of the most valuable materials with high thermal conductivity (above 1750 W/m K compared to thermal conductivity of Ag 419 W/m K). Owing to their very high thermal conductivity, CNTs are one of the most suitable nanoadditives in fabricating the nanofluid with thermal conductivities that are significantly higher than those of the parent liquids even when the CNTs’ concentrations are negligible. This work presents a modified model for predicting the thermal conductivity of carbon nanotube-nanofluids (CNT-nanofluids), which take into consideration the effects of size, volume fraction, and thermal conductivity of CNTs as well as the properties of base liquid. The modified model is found to correctly predict the trends observed in experimental data for different combinations of CNT-nanofluids with varying concentrations.
Striped pattern selection by advective reaction-diffusion systems: Resilience of banded vegetation on slopes
Authors: Siero E. , Doelman A. , Eppinga M. B. , Rademacher J. D. M. , Rietkerk M. , Siteur K.
Published: March 2015

For water-limited arid ecosystems, where water distribution and infiltration play a vital role, various models have been set up to explain vegetation patterning. On sloped terrains, vegetation aligned in bands has been observed ubiquitously. In this paper, we consider the appearance, stability, and bifurcations of 2D striped or banded patterns in an arid ecosystem model. We numerically show that the resilience of the vegetation bands is larger on steeper slopes by computing the stability regions (Busse balloons) of striped patterns with respect to 1D and transverse 2D perturbations. This is corroborated by numerical simulations with a slowly decreasing water input parameter. Here, long wavelength striped patterns are unstable against transverse perturbations, which we also rigorously prove on flat ground through an Evans function approach. In addition, we prove a “Squire theorem” for a class of two-component reaction-advection-diffusion systems that includes our model, showing that the onset of pattern formation in 2D is due to 1D instabilities in the direction of advection, which naturally leads to striped patterns.
Barrierless proton transfer across weak CH⋯O hydrogen bonds in dimethyl ether dimer
Authors: Yoder Bruce L. , Bravaya Ksenia B. , Bodi Andras , West Adam H. C. , Sztáray Bálint , Signorell Ruth
Published: March 2015

We present a combined computational and threshold photoelectron photoion coincidence study of two isotopologues of dimethyl ether, (DME − h6)n and (DME − d6)n n = 1 and 2, in the 9–14 eV photon energy range. Multiple isomers of neutral dimethyl ether dimer were considered, all of which may be present, and exhibited varying C–H⋯O interactions. Results from electronic structure calculations predict that all of them undergo barrierless proton transfer upon photoionization to the ground electronic state of the cation. In fact, all neutral isomers were found to relax to the same radical cation structure. The lowest energy dissociative photoionization channel of the dimer leads to CH3OHCH3+ by the loss of CH2OCH3 with a 0 K appearance energy of 9.71 ± 0.03 eV and 9.73 ± 0.03 eV for (DME − h6)2 and deuterated (DME − d6)2, respectively. The ground state threshold photoelectron spectrum band of the dimethyl ether dimer is broad and exhibits no vibrational structure. Dimerization results in a 350 meV decrease of the valence band appearance energy, a 140 meV decrease of the band maximum, thus an almost twofold increase in the ground state band width, compared with DME − d6 monomer.
Characterization of three-dimensional structure using images
Authors: Liu Bin , Goree J. , Suranga Ruhunusiri W. D.
Published: March 2015

The pair correlation function g(r) and the number density n for particles in a three-dimensional (3D) sample can be determined from a single two-dimensional (2D) image. The 2D image is obtained experimentally with a simple setup: a cross-sectional slab of particles is illuminated with a laser sheet and imaged with a single camera. After image analysis, to find positions of particles in two dimensions, along with their brightness, one obtains g(r), also known as the radial distribution function. The key for attaining high accuracy is to use only the particles that are brighter than a filter level, which we refine to achieve greater accuracy. The density n is obtained from g(r). This method is demonstrated in a dusty plasma experiment. Accuracy is quantified using simulation data; errors of 2% for both the pair correlation function and the number density are achievable. The method is useful for dusty plasmas and colloids.
Gravity currents propagating up a slope in a two-layer fluid
Authors: Marleau Larissa J. , Flynn Morris R. , Sutherland Bruce R.
Published: March 2015

Gravity currents produced by partial-depth lock-release and travelling along the base of a two-layer stratified ambient are investigated as they propagate along a rising slope. The initial gravity current front speed is found to be consistent with a theory adapted from Shin et al. [“Gravity currents produced by lock exchange,” J. Fluid Mech. 521, 1-34 (2004)] to the case of partial-depth currents in two-layer ambients. The subsequent evolution depends on the gravity current speed relative to the speed of the interfacial disturbance it creates. The deceleration of supercritical gravity currents, which travel faster than the interfacial disturbance, is gradual and agrees well with the relationship developed by Marleau et al. [“Gravity currents propagating up a slope,” Phys. Fluids 26, 046605 (2014)] for upslope gravity currents in uniform density ambients. In several subcritical cases, the gravity current suddenly came to rest as a consequence of interactions with the interfacial disturbance. The disturbance amplitude, speed, and width are found to be nearly constant during its evolution. In cases for which the ambient interface intersected the bottom slope, the amplitude, speed, and width were nearly constant up to the point where the lower layer shallowed and the disturbance transformed into an upslope-propagating gravity current.
Excitonic optical properties of wurtzite ZnS quantum dots under pressure
Authors: Zeng Zaiping , Garoufalis Christos S. , Baskoutas Sotirios , Bester Gabriel
Published: March 2015

By means of atomistic empirical pseudopotentials combined with a configuration interaction approach, we have studied the optical properties of wurtzite ZnS quantum dots in the presence of strong quantum confinement effects as a function of pressure. We find the pressure coefficients of quantum dots to be highly size-dependent and reduced by as much as 23% in comparison to the bulk value of 63 meV/GPa obtained from density functional theory calculations. The many-body excitonic effects on the quantum dot pressure coefficients are found to be marginal. The absolute gap deformation potential of quantum dots originates mainly from the energy change of the lowest unoccupied molecular orbital state. Finally, we find that the exciton spin-splitting increases nearly linearly as a function of applied pressure.
Analysis of the spin Hall effect in CuIr alloys: Combined approach of density functional theory and Hartree-Fock approximation
Authors: Xu Zhuo , Gu Bo , Mori Michiyasu , Ziman Timothy , Maekawa Sadamichi
Published: March 2015

We analyze the spin Hall effect in CuIr alloys in theory by the combined approach of the density functional theory (DFT) and Hartree-Fock (HF) approximation. The spin Hall angle (SHA) is obtained to be negative without the local correlation effects. After including the local correlation effects of the 5d orbitals of Ir impurities, the SHA becomes positive with realistic correlation parameters and consistent with experiment [Niimi et al., Phys. Rev. Lett. 106, 126601 (2011)]. Moreover, our analysis shows that the DFT + HF approach is a convenient and general method to study the influence of local correlation effects on the spin Hall effect.
Post-assembly magnetization of a 100 kW high speed permanent magnet rotor
Authors: Lv Yiliang , Wang Guobin , Li Liang
Published: March 2015

A post-assembly magnetizing fixture has been designed and successfully used to magnetize the rotor of a 100 kW high speed permanent magnet synchronous motor. The rotor is a solid cylinder with outer diameter of 80 mm and total length of 515 mm. The permanent magnet material is samarium-cobalt (Sm2Co17) with saturation magnetizing field of 6 T. The mechanical stability of the magnetizing fixture has been studied as well as the general design methodology. The magnetizing coil is subdivided in order to reduce the electromagnetic force, and the coils are separately reinforced in different ways. The electromagnetic and structural optimization is performed by finite element analysis and verified by experiments.
Synchronization, non-linear dynamics and low-frequency fluctuations: Analogy between spontaneous brain activity and networked single-transistor chaotic oscillators
Authors: Minati Ludovico , Chiesa Pietro , Tabarelli Davide , D'Incerti Ludovico , Jovicich Jorge
Published: March 2015

In this paper, the topographical relationship between functional connectivity (intended as inter-regional synchronization), spectral and non-linear dynamical properties across cortical areas of the healthy human brain is considered. Based upon functional MRI acquisitions of spontaneous activity during wakeful idleness, node degree maps are determined by thresholding the temporal correlation coefficient among all voxel pairs. In addition, for individual voxel time-series, the relative amplitude of low-frequency fluctuations and the correlation dimension (D2), determined with respect to Fourier amplitude and value distribution matched surrogate data, are measured. Across cortical areas, high node degree is associated with a shift towards lower frequency activity and, compared to surrogate data, clearer saturation to a lower correlation dimension, suggesting presence of non-linear structure. An attempt to recapitulate this relationship in a network of single-transistor oscillators is made, based on a diffusive ring (n = 90) with added long-distance links defining four extended hub regions. Similarly to the brain data, it is found that oscillators in the hub regions generate signals with larger low-frequency cycle amplitude fluctuations and clearer saturation to a lower correlation dimension compared to surrogates. The effect emerges more markedly close to criticality. The homology observed between the two systems despite profound differences in scale, coupling mechanism and dynamics appears noteworthy. These experimental results motivate further investigation into the heterogeneity of cortical non-linear dynamics in relation to connectivity and underline the ability for small networks of single-transistor oscillators to recreate collective phenomena arising in much more complex biological systems, potentially representing a future platform for modelling disease-related changes.
A super-discrete variational identity and its application for constructing super-discrete Hamiltonian systems
Authors: Li Xin-Yue , Zhao Qiu-Lan , Li Yu-Xia , Dong Huan-He
Published: March 2015

In the paper, a super-discrete variational identity on Lie super-algebras is established first. It provides an approach for constructing super-discrete Hamiltonian structures of super evolution lattice equations with discrete zero curvature representation when the super-spectral matrix U is selected appropriately. As an application, super-discrete Hamiltonian structures of super-Toda lattice hierarchy are developed and this method can be used to construct super-discrete bi-Hamiltonian structures of more super-discrete integrable evolutive hierarchies. Super-discrete variational identity is devoted to deduce super-integrability and solutions of super-discrete integrable equations.
Richtmyer-Meshkov evolution under steady shock conditions in the high-energy-density regime
Authors: Di Stefano C. A. , Malamud G. , Kuranz C. C. , Klein S. R. , Stoeckl C. , Drake R. P.
Published: March 2015

This work presents direct experimental evidence of long-predicted nonlinear aspects of the Richtmyer-Meshkov process, in which new modes first arise from the coupling of initially-present modes, and in which shorter-wavelength modes are eventually overtaken by longer-wavelength modes. This is accomplished using a technique we developed employing a long driving laser pulse to create a strong (Mach ∼ 8) shock across a well-characterized material interface seeded by a two-mode sinusoidal perturbation. This technique further permits the shock to be sustained, without decay of the high-energy-density flow conditions, long enough for the system to evolve into the nonlinear phase.
Holmium hafnate: An emerging electronic device material
Authors: Pavunny Shojan P. , Sharma Yogesh , Kooriyattil Sudheendran , Dugu Sita , Katiyar Rajesh K. , Scott James F. , Katiyar Ram S.
Published: March 2015

We report structural, optical, charge transport, and temperature properties as well as the frequency dependence of the dielectric constant of Ho2Hf2O7 (HHO) which make this material desirable as an alternative high-k dielectric for future silicon technology devices. A high dielectric constant of ∼20 and very low dielectric loss of ∼0.1% are temperature and voltage independent at 100 kHz near ambient conditions. The Pt/HHO/Pt capacitor exhibits exceptionally low Schottky emission-based leakage currents. In combination with the large observed bandgap Eg of 5.6 eV, determined by diffuse reflectance spectroscopy, our results reveal fundamental physics and materials science of the HHO metal oxide and its potential application as a high-k dielectric for the next generation of complementary metal-oxide-semiconductor devices.
Encapsulated graphene field-effect transistors for air stable operation
Authors: Alexandrou Konstantinos , Petrone Nicholas , Hone James , Kymissis Ioannis
Published: March 2015

In this work, we report the fabrication of encapsulated graphene field effects transistors (GFETs) with excellent air stability operation in ambient environment. Graphene's 2D nature makes its electronics properties very sensitive to the surrounding environment, and thus, non-encapsulated graphene devices show extensive vulnerability due to unintentional hole doping from the presence of water molecules and oxygen limiting their performance and use in real world applications. Encapsulating GFETs with a thin layer of parylene-C and aluminum deposited on top of the exposed graphene channel area resulted in devices with excellent electrical performance stability for an extended period of time. Moisture penetration is reduced significantly and carrier mobility degraded substantially less when compared to non-encapsulated control devices. Our CMOS compatible encapsulation method minimizes the problems of environmental doping and lifetime performance degradation, enabling the operation of air stable devices for next generation graphene-based electronics.
A high efficiency hybrid stirling-pulse tube cryocooler
Authors: Wang Xiaotao , Zhang Yibing , Li Haibing , Dai Wei , Chen Shuai , Lei Gang , Luo Ercang
Published: March 2015

This article presented a hybrid cryocooler which combines the room temperature displacers and the pulse tube in one system. Compared with a traditional pulse tube cryocooler, the system uses the rod-less ambient displacer to recover the expansion work from the pulse tube cold end to improve the efficiency while still keeps the advantage of the pulse tube cryocooler with no moving parts at the cold region. In the meantime, dual-opposed configurations for both the compression pistons and displacers reduce the cooler vibration to a very low level. In the experiments, a lowest no-load temperature of 38.5 K has been obtained and the cooling power at 80K was 26.4 W with an input electric power of 290 W. This leads to an efficiency of 24.2% of Carnot, marginally higher than that of an ordinary pulse tube cryocooler. The hybrid configuration herein provides a very competitive option when a high efficiency, high-reliability and robust cryocooler is desired.
Cortical network models of impulse firing in the resting and active states predict cortical energetics
Authors: Bennett Maxwell R. , Farnell Les , Gibson William G. , Lagopoulos Jim
Published: March 2015

Significance

Cortical metabolic rate of glucose oxidation [CMR
glc(ox)
] measurements have provided quantitative estimates of cortical energetics associated with a number of physiological states, such as those that occur during sleep or under anesthesia. Recently, a strict quantitative relationship has been established between synaptic and action potential activity in a region of cortex and such measurements of CMR
glc(ox)
, allowing neural networks to be used to probe the mechanistic basis of the CMR
glc(ox)
observations. Here, we use models of brain networks to provide such insights.
Reprogramming of primary human Philadelphia chromosome-positive B cell acute lymphoblastic leukemia cells into nonleukemic macrophages
Authors: McClellan James Scott , Dove Christopher , Gentles Andrew J. , Ryan Christine E. , Majeti Ravindra
Published: March 2015

Significance

Precursor B cell acute lymphoblastic leukemia (B-ALL) is an aggressive cancer of white blood cells with a poor prognosis. The cancerous cells in this disease are immature B cells, which are unable to fully differentiate into normal B cells. We show here that cancerous cells from B-ALL patients can be reprogrammed, causing them to change into cells that resemble normal macrophages and can perform macrophage-associated functions such as the consumption of bacteria. Importantly, unlike typical B-ALL cells, these reprogrammed cells are no longer able to cause disease in immunodeficient mice. Finally, we show that this reprogramming process may occur to some degree in patients with B-ALL. This indicates that reprogramming B-ALL cells into macrophages might represent a previously unidentified therapeutic strategy.
Biasing moral decisions by exploiting the dynamics of eye gaze
Authors: Pärnamets Philip , Johansson Petter , Hall Lars , Balkenius Christian , Spivey Michael J. , Richardson Daniel C.
Published: March 2015

Significance

Where people look generally reflects and reveals their moment-by-moment thought processes. This study introduces an experimental method whereby participants’ eye gaze is monitored and information about their gaze is used to change the timing of their decisions. Answers to difficult moral questions such as “Is murder justifiable?” can be influenced toward random alternatives based on looking patterns alone. We do this without presenting different arguments or response frames, as in other techniques of persuasion. Thus, the process of arriving at a moral decision is not only reflected in a participant’s eye gaze but can also be determined by it.
Neuropeptide Y stimulates autophagy in hypothalamic neurons
Authors: Aveleira Célia A. , Botelho Mariana , Carmo-Silva Sara , Pascoal Jorge F. , Ferreira-Marques Marisa , Nóbrega Clévio , Cortes Luísa , Valero Jorge , Sousa-Ferreira Lígia , Álvaro Ana R. , Santana Magda , Kügler Sebastian , Pereira de Almeida Luís , Cavadas Cláudia
Published: March 2015

Significance

Autophagy impairment is a major hallmark of aging, and any intervention that enhances autophagy is of potential interest to delay aging. However, it was described that the hypothalamus is a brain area with a key role on whole-body aging. In the present study, we show that an endogenous molecule produced by the hypothalamus, the neuropeptide Y (NPY), stimulates autophagy in rodent hypothalamus. Because both hypothalamic autophagy and NPY levels decrease with age, a better understanding of hypothalamic neuronal autophagy regulation by NPY may provide new putative therapeutic strategies to ameliorate age-related deteriorations and delay aging.
Heteromerization of chemokine (C-X-C motif) receptor 4 with α1A/B-adrenergic receptors controls α1-adrenergic receptor function
Authors: Tripathi Abhishek , Vana P. Geoff , Chavan Tanmay S. , Brueggemann Lioubov I. , Byron Kenneth L. , Tarasova Nadya I. , Volkman Brian F. , Gaponenko Vadim , Majetschak Matthias
Published: March 2015

Significance

α1-Adrenergic receptors are important for the regulation of vascular function and are targeted clinically for blood pressure control. Here, we provide evidence that α1A/B-adrenergic receptors (AR) form heteromeric complexes with chemokine (C-X-C motif) receptor 4 (CXCR4) on the cell surface of vascular smooth muscle cells. We show that disruption of α1A/B-AR:CXCR4 heteromeric complexes inhibits α1-AR–mediated functions in vascular smooth muscle cells and that treatment with CXCR4 agonists enhances the potency of the α1-AR agonist phenylephrine to increase blood pressure. These findings extend the current understanding of the molecular mechanisms regulating α1-AR and provide an example of G protein-coupled receptor heteromerization with important functional implications. Compounds targeting the α1A/B-AR:CXCR4 interaction could provide an alternative pharmacological approach to modulating blood pressure.
Prosurvival Bcl-2 family members reveal a distinct apoptotic identity between conventional and plasmacytoid dendritic cells
Authors: Carrington Emma M. , Zhang Jian-Guo , Sutherland Robyn M. , Vikstrom Ingela B. , Brady Jamie L. , Soo Priscilla , Vremec David , Allison Cody , Lee Erinna F. , Fairlie W. Douglas , Bouillet Philippe , Grabow Stephanie , Ottina Eleonora , Herold Marco J. , Pellegrini Marc , Huang David C. S. , Tarlinton David M. , Strasser Andreas , Lew Andrew M. , Zhan Yifan
Published: March 2015

Significance

Dendritic cells (DCs) are pivotal for immune responses as they present antigens to T cells. Different DC subsets have different functions and are associated with different diseases. For example, plasmacytoid DCs (pDCs) produce type 1 interferons and are associated with the autoimmune disease, systemic lupus erythematosus. Understanding control of survival/apoptosis in different DC subsets may not only provide a molecular basis for their homeostasis but also guide therapeutic intervention of immunopathology. We revealed that two major DC subsets (pDCs and conventional DCs) express distinct BCL-2 family proteins at different levels and this correlated with their survival requirements. Accordingly, clinically applicable antagonist drugs killed the appropriate DC subsets, informing on the future use of these compounds for treating immune-mediated damage.
Double-stranded DNA translocase activity of transcription factor TFIIH and the mechanism of RNA polymerase II open complex formation
Authors: Fishburn James , Tomko Eric , Galburt Eric , Hahn Steven
Published: March 2015

Significance

How ATP hydrolysis is coupled to promoter DNA unwinding and open complex formation at RNA polymerase II (Poll II) promoters is a longstanding question. Of the multisubunit RNA polymerases, only Pol II requires ATP for DNA unwinding. Here we show that the general transcription factor TFIIH subunit Ssl2 is a double-stranded DNA translocase. These and other data suggest that Ssl2 promotes DNA opening by tracking along the nontemplate promoter strand, rotating and inserting DNA into the Pol II active site cleft, leading to DNA unwinding. Our accompanying biochemical studies explain why the open complex is unstable and how TFIIH can promote Pol II escape from the promoter. Our findings also have important implications for the mechanism of TFIIH-mediated DNA repair.
Glucocorticoid-resistant Th17 cells are selectively attenuated by cyclosporine A
Authors: Schewitz-Bowers Lauren P. , Lait Philippa J. P. , Copland David A. , Chen Ping , Wu Wenting , Dhanda Ashwin D. , Vistica Barbara P. , Williams Emily L. , Liu Baoying , Jawad Shayma , Li Zhiyu , Tucker William , Hirani Sima , Wakabayashi Yoshiyuki , Zhu Jun , Sen Nida , Conway-Campbell Becky L. , Gery Igal , Dick Andrew D. , Wei Lai , Nussenblatt Robert B. , Lee Richard W. J.
Published: March 2015

Significance

Cyclosporine A was one of the first drugs used in clinical practice to successfully rescue glucocorticoid-resistant inflammatory diseases. In this article we extend the characterization of glucocorticoid-resistant human Th17 cells, and demonstrate that this effector memory T-cell subset is reciprocally attenuated by cyclosporine A. This therapeutic paradigm was confirmed in a murine model of autoimmunity, refining our understanding of cyclosporine A’s effect on the adaptive immune response. These data support the rationale for Th17-targeting therapies in the treatment of glucocorticoid-resistant inflammation.
Altered cofactor regulation with disease-associated p97/VCP mutations
Authors: Zhang Xiaoyi , Gui Lin , Zhang Xiaoyan , Bulfer Stacie L. , Sanghez Valentina , Wong Daniel E. , Lee YouJin , Lehmann Lynn , Lee James Siho , Shih Pei-Yin , Lin Henry J. , Iacovino Michelina , Weihl Conrad C. , Arkin Michelle R. , Wang Yanzhuang , Chou Tsui-Fen
Published: March 2015

Significance

Age-associated degenerative diseases have similar pathogenic mechanisms related to defects in protein homeostasis. p97/VCP (valosin-containing protein) is essential for coordinating protein degradation and is mutated in a multisystem degenerative disease that affects the central nervous system, muscle, and bone. p97/VCP is an enzyme in the AAA ATPases (ATPases associated with diverse cellular activities) family, which takes apart ATP and uses this energy to perform pivotal functions. We found that p97/VCP cofactors control its enzymatic activity. p97/VCP disease mutants behave abnormally due to lack of appropriate control by these cofactors. Correcting the function of the disease-associated proteins may be a desirable approach to developing safe treatment for fatal degenerative diseases. The next steps are to screen and characterize large panels of compounds to identify potential drugs that may correct the malfunction.
Structural mechanism of sensing long dsRNA via a noncatalytic domain in human oligoadenylate synthetase 3
Authors: Donovan Jesse , Whitney Gena , Rath Sneha , Korennykh Alexei
Published: March 2015

Significance

Double-stranded RNA (dsRNA) is a pathogen-associated molecular pattern that triggers the type-I interferon (IFN) response in mammalian cells. The IFN response up-regulates several dsRNA sensors, including closely related oligoadenylate synthetases (OAS). The functional roles of different oligoadenylate synthetases in dsRNA surveillance are not understood. Here, we use X-ray crystallography and biochemistry to demonstrate that human OAS1 and OAS3 recognize dsRNA molecules of different length. We show that domain duplication accompanied by a loss of catalytic activity provides the mechanism for sensing long dsRNA by OAS3. Our studies thus reveal different functions of OAS1 and OAS3 in dsRNA surveillance, identify a key role of domain duplication in the OAS family, and advance the fundamental understanding of the human innate immune system.
Half-century evidence from western Canada shows forest dynamics are primarily driven by competition followed by climate
Authors: Zhang Jian , Huang Shongming , He Fangliang
Published: March 2015

Significance

Forests worldwide have undergone rapid changes; however, understanding the causes of the changes has been a challenge. Climate on the regional scale has been overwhelmingly presumed to drive these changes, with little attention paid to the possible effects of competition. We compiled a long-term forest dataset from western Canada to study the relative importance of climate change and competition on tree growth, mortality, and recruitment. We showed that competition was the primary factor causing the long-term changes. Regional climate had a weaker yet significant effect on tree mortality, but no effect on tree growth and recruitment. This finding suggests that forest studies focused solely on the effects of climate may overlook the effect of other processes critical to forest dynamics.
Surface biosignatures of exo-Earths: Remote detection of extraterrestrial life
Authors: Hegde Siddharth , Paulino-Lima Ivan G. , Kent Ryan , Kaltenegger Lisa , Rothschild Lynn
Published: March 2015

Significance

We develop the first catalogue, to our knowledge, of reflectance spectra for a diverse range of pigmented microorganisms, including ones that were isolated from Earth’s most extreme environments. This catalogue provides a broad scope of surface signatures for life on exoplanets, which could provide different conditions from those on Earth, allowing, for example, extremophiles on Earth to become the predominant life form. Much of the history of life on Earth has been dominated by microbial life, and it is likely that life on exoplanets evolves through single-celled stages prior to multicellular creatures. Here, we present the first database, to our knowledge, for such surface features in preparation for the next generation of space- and ground-based telescopes that will search for a wide variety of life on exoplanets.
A 17-My-old whale constrains onset of uplift and climate change in east Africa
Authors: Wichura Henry , Jacobs Louis L. , Lin Andrew , Polcyn Michael J. , Manthi Fredrick K. , Winkler Dale A. , Strecker Manfred R. , Clemens Matthew
Published: March 2015

Significance

An enigmatic fossil representing the deep-diving, open-ocean whale family Ziphiidae found 740 km inland and at 620 m elevation in West Turkana, Kenya was rediscovered after it went missing for more than 30 years. This stranded whale fossil provides the first constraint on the initiation of east African uplift from near sea level at 17 Ma, limiting the timing and initial elevation of environmental change indicated by geodynamic and climatic modeling, paleosols, isotopes, paleobotany, and the mammalian fossil record. At 17 Ma, elevation was low, rainfall was high, vegetation was forested, and mammalian communities contained immigrants and native African species, including diverse primates. Uplift resulted in increasing aridity and open habitats that drove human evolution.