bluuebunny/crossref_metadata_2025 huggingface dataset:
Novel PtO decorated MWCNTs as a highly efficient counter electrode for dye-sensitized solar cells
Authors: Chen Xiao , Guo Jian Wei , Hou Yu , Li Yu Hang , Yang Shuang , Zheng Li Rong , Zhang Bo , Yang Xiao Hua , Yang Hua Gui
Published: December 2014

PtO–MWCNTs nanocomposites were prepared and applied as the counter electrode in dye-sensitized solar cells (DSCs) for the first time. Excellent energy conversion efficiency indicated that the nanocomposite was a promising electrocatalyst for DSCs.
NiFe2O4, Fe3O4–FexNiy or FexNiy loaded porous activated carbon balls as lightweight microwave absorbents
Authors: Li Guomin , Wang Liancheng , Li Wanxi , Xu Yao
Published: December 2014

The ferromagnetic PACB composites annealed at different temperatures in an Ar atmosphere exhibit varied crystalline phase, morphology and high-performance microwave absorbability.
Gold nanostars as SERS-active substrates for FT-Raman spectroscopy
Authors: Zoppi Angela , Trigari Silvana , Margheri Giancarlo , Muniz-Miranda Maurizio , Giorgetti Emilia
Published: December 2014

Surfactant-free and CTAB-stabilized gold nanostars were synthesized. Their FT-SERS activity was tested. A nanomolar limit of detection and a Raman enhancement factor of more than 105 were found.
Inter-solubility of product systems in biodiesel production from Jatropha curcas L. oil with the switchable solvent DBU/methanol
Authors: Bao Jinzhi , Liu Yingying , Parnas Richard , Liang Bin , Lu Houfang
Published: December 2014

Increasing the dosage of DBU and/or temperature enhances the distribution and solubility of methanol, DBU and glycerol in the biodiesel-rich phase.
tert-Butyl hypochlorite mediated diastereoselective oxidative coupling: access to 1-functionalized tetrahydrocarbazoles
Authors: Jiang Long , Xie Xiaoni , Zu Liansuo
Published: December 2014

A mild and operationally simple protocol for the diastereoselective C–H functionalization of the 1-position of tetrahydrocarbazoles is reported.
A porous polyethersulfone hollow fiber membrane in a gas humidification process
Authors: Bakeri Gh. , Naeimifard S. , Matsuura T. , Ismail A. F.
Published: December 2014

Porous PES hollow fiber membrane was fabricated and characterized in terms of pore size, porosity and wettability and used in humidification process. The membrane showed high performance compared to the commercial and in-house made membranes.
Metal-free ring expansion of indoles with nitroalkenes: a simple, modular approach to 3-substituted 2-quinolones
Authors: Aksenov Alexander V. , Smirnov Alexander N. , Aksenov Nicolai A. , Aksenova Inna V. , Matheny Jonathon P. , Rubin Michael
Published: December 2014

3-Substituted 2-quinolones are obtained via a novel metal-free transannulation reaction of 2-nitroolefins with 2-substituted indoles in polyphosphoric acid.
Structure, magnetism and catecholase activity of the first dicopper(ii) complex having a single μ-alkoxo bridge
Authors: Adhikari Sangita , Banerjee Arnab , Nandi Sandip , Fondo Matilde , Sanmartín-Matalobos Jesús , Das Debasis
Published: December 2014

Pyridine-2,6-dimethanol shows a neutral, monoanionic and dianionic coordination behaviour with two different coordination modes viz. tridentate and bidentate towards Cu(ii), leading to three different geometric environments around Cu(ii) centers.
An efficient and green synthesis of xanthene derivatives using CuS quantum dots as a heterogeneous and reusable catalyst under solvent free conditions
Authors: Bansal Pratibha , Chaudhary Ganga Ram , Kaur Navneet , Mehta S. K.
Published: December 2014

CuS quantum dots have been proven to be an efficient catalyst in the synthesis of xanthenes in terms of high yield, reduction of time and energy consumption under solvent free conditions with easy work up.
Phase diagram, structures and magnetism of the FeMnP1−xSix-system
Authors: Höglin Viktor , Cedervall Johan , Andersson Mikael Svante , Sarkar Tapati , Hudl Matthias , Nordblad Per , Andersson Yvonne , Sahlberg Martin
Published: December 2014

Phase diagram of FeMnP1−xSix. White regions represent single phases. Multiple phase regions are grey.
Optimizing gold nanoparticle seeding density on DNA origami
Authors: Gates E. P. , Jensen J. K. , Harb J. N. , Woolley A. T.
Published: December 2014

Characterization of various experimental parameters leads to optimized conditions for depositing linear strings of gold nanoparticle seeds on DNA origami.
From metal–organic frameworks to magnetic nanostructured porous carbon composites: towards highly efficient dye removal and degradation
Authors: Zhang Cong , Ye Fanggui , Shen Shufen , Xiong Yuhao , Su Linjing , Zhao Shulin
Published: December 2014

A magnetic nanostructured porous carbon material (γ-Fe2O3/C) was easily synthesized using a microwave-enhanced high-temperature ionothermal method with an iron terephthalate metal–organic framework-MIL-53(Fe), as a template.
Assessing motivation to learn chemistry: adaptation and validation of Science Motivation Questionnaire II with Greek secondary school students
Authors: Salta Katerina , Koulougliotis Dionysios
Published: December 2014

In educational research, the availability of a validated version of an original instrument in a different language offers the possibility for valid measurements obtained within the specific educational context and in addition it provides the opportunity for valid cross-cultural comparisons. The present study aimed to adapt the Science Motivation Questionnaire II (SMQ II) for application to a different cultural context (Greece), a different age group (secondary school students) and with a focus on chemistry learning. Subsequently, the Greek version of Chemistry Motivation Questionnaire II (Greek CMQ II) was used in order to investigate Greek secondary school students' motivation to learn chemistry for the first time. The sample consisted of 330 secondary school students (163 boys–167 girls), of which 146 were in lower secondary school (14–15 years old) and 184 were in upper secondary school (16–17 years old). Confirmatory factor analyses provided evidence for the validity of Greek CMQ II, as well as for configural, metric and scalar invariance, thus allowing meaningful comparisons between groups. The five motivation components of the original instrument namely grade motivation, career motivation, intrinsic motivation, self-efficacy, and self-determination were confirmed. Gender-based comparisons showed that girls had higher self-determination relative to the boys irrespective of the age group. In addition, girls in lower secondary school had higher career and intrinsic motivation relative to the boys of the same age group. Age-based comparisons showed that lower secondary school students had higher grade motivation relative to upper secondary school students.
Tap density equations of granular powders based on the rate process theory and the free volume concept
Authors: Hao Tian
Published: December 2014

The tap density of a granular powder is often linked to the flowability via the Carr index that measures how tight a powder can be packed, under an assumption that more easily packed powders usually flow poorly.
Mechanically and chemically robust ZIF-8 monoliths with high volumetric adsorption capacity
Authors: Tian Tian , Velazquez-Garcia Jose , Bennett Thomas D. , Fairen-Jimenez David
Published: December 2014

The resultant monoliths are mechanically robust structures and present up to 3 times higher volumetric adsorption capacities than the conventional, powder MOF.
High performance inverted structure perovskite solar cells based on a PCBM:polystyrene blend electron transport layer
Authors: Bai Yang , Yu Hui , Zhu Zonglong , Jiang Kui , Zhang Teng , Zhao Ni , Yang Shihe , Yan He
Published: December 2014

Hybrid organic/inorganic perovskite solar cells are among the most competitive emerging photovoltaic technologies.
Direct plasma deposition of amorphous Si/C nanocomposites as high performance anodes for lithium ion batteries
Authors: Chang Xinghua , Li Wei , Yang Junfeng , Xu Li , Zheng Jie , Li Xingguo
Published: December 2014

One step plasma deposited Si/C nanocomposites as high capacity, high stability lithium ion battery anodes.
Hydrothermally synthesized CuxO as a catalyst for CO oxidation
Authors: Guo Mu Yao , Liu Fangzhou , Tsui Jenkin , Voskanyan Albert A. , Ng Alan Man Ching , Djurišić Aleksandra B. , Chan Wai Kin , Chan Kwong-Yu , Liao Changzhong , Shih Kaimin , Surya Charles
Published: December 2014

Hydrothermally synthesized CuxO exhibited improved performance for CO oxidation compared to the hydrothermally synthesized Cu2O, as well as commercial CuO nanoparticles.
Cytotoxic effects and cellular oxidative mechanisms of metallic nanoparticles on renal tubular cells: impact of particle solubility
Authors: Pujalté Igor , Passagne Isabelle , Daculsi Richard , de Portal Caroline , Ohayon-Courtès Céline , L'Azou Béatrice
Published: December 2014

Many uncertainties remain regarding the potential toxic effect of nanoparticles.
Quantum dots exposure alters both development and function of D-type GABAergic motor neurons in nematode Caenorhabditis elegans
Authors: Zhao Yunli , Wang Xiong , Wu Qiuli , Li Yiping , Tang Meng , Wang Dayong
Published: December 2014

Both translocation into targeted neurons and developmental and functional alterations in targeted neurons contribute to CdTe QDs neurotoxicity.
Light manipulation with encoded plasmonic nanostructures
Authors: Zhao Chenglong , Zhang Jiasen , Liu Yongmin
Published: December 2014

Plasmonics, which allows for manipulation of light field beyond the fundamental diffraction limit, has recently attracted tremendous research efforts. The propagating surface plasmon polaritons (SPPs) confined on a metal-dielectric interface provide an ideal two-dimensional (2D) platform to develop subwavelength optical circuits for on-chip information processing and communication. The surface plasmon resonance of rationally designed metallic nanostructures, on the other hand, enables pronounced phase and polarization modulation for light beams travelling in three-dimensional (3D) free space. Flexible 2D and free-space propagating light manipulation can be achieved by encoding plasmonic nanostructures on a 2D surface, promising the design, fabrication and integration of the next-generation optical architectures with substantially reduced footprint. It is envisioned that the encoded plasmonic nanostructures can significantly expand available toolboxes for novel light manipulation. In this review, we presents the fundamentals, recent developments and future perspectives in this emerging field, aiming to open up new avenues to developing revolutionary photonic devices.
Periodic discrete energy for long-range potentials
Authors: Hardin D. P. , Saff E. B. , Simanek B.
Published: December 2014

We consider periodic energy problems in Euclidean space with a special emphasis on long-range potentials that cannot be defined through the usual infinite sum. One of our main results builds on more recent developments of Ewald summation to define the periodic energy corresponding to a large class of long-range potentials. Two particularly interesting examples are the logarithmic potential and the Riesz potential when the Riesz parameter is smaller than the dimension of the space. For these examples, we use analytic continuation methods to provide concise formulas for the periodic kernel in terms of the Epstein Hurwitz Zeta function. We apply our energy definition to deduce several properties of the minimal energy including the asymptotic order of growth and the distribution of points in energy minimizing configurations as the number of points becomes large. We conclude with some detailed calculations in the case of one dimension, which shows the utility of this approach.
Contributed Review: The feasibility of a fully miniaturized magneto-optical trap for portable ultracold quantum technology
Authors: Rushton J. A. , Aldous M. , Himsworth M. D.
Published: December 2014

Experiments using laser cooled atoms and ions show real promise for practical applications in quantum-enhanced metrology, timing, navigation, and sensing as well as exotic roles in quantum computing, networking, and simulation. The heart of many of these experiments has been translated to microfabricated platforms known as atom chips whose construction readily lend themselves to integration with larger systems and future mass production. To truly make the jump from laboratory demonstrations to practical, rugged devices, the complex surrounding infrastructure (including vacuum systems, optics, and lasers) also needs to be miniaturized and integrated. In this paper we explore the feasibility of applying this approach to the Magneto-Optical Trap; incorporating the vacuum system, atom source and optical geometry into a permanently sealed micro-litre system capable of maintaining 10−10 mbar for more than 1000 days of operation with passive pumping alone. We demonstrate such an engineering challenge is achievable using recent advances in semiconductor microfabrication techniques and materials.
A force calibration standard for magnetic tweezers
Authors: Yu Zhongbo , Dulin David , Cnossen Jelmer , Köber Mariana , van Oene Maarten M. , Ordu Orkide , Berghuis Bojk A. , Hensgens Toivo , Lipfert Jan , Dekker Nynke H.
Published: December 2014

To study the behavior of biological macromolecules and enzymatic reactions under force, advances in single-molecule force spectroscopy have proven instrumental. Magnetic tweezers form one of the most powerful of these techniques, due to their overall simplicity, non-invasive character, potential for high throughput measurements, and large force range. Drawbacks of magnetic tweezers, however, are that accurate determination of the applied forces can be challenging for short biomolecules at high forces and very time-consuming for long tethers at low forces below ∼1 piconewton. Here, we address these drawbacks by presenting a calibration standard for magnetic tweezers consisting of measured forces for four magnet configurations. Each such configuration is calibrated for two commonly employed commercially available magnetic microspheres. We calculate forces in both time and spectral domains by analyzing bead fluctuations. The resulting calibration curves, validated through the use of different algorithms that yield close agreement in their determination of the applied forces, span a range from 100 piconewtons down to tens of femtonewtons. These generalized force calibrations will serve as a convenient resource for magnetic tweezers users and diminish variations between different experimental configurations or laboratories.
States that “look the same” with respect to every basis in a mutually unbiased set
Authors: Amburg Ilya , Sharma Roshan , Sussman Daniel M. , Wootters William K.
Published: December 2014

A complete set of mutually unbiased bases (MUBs) in a Hilbert space of dimension d defines a set of d + 1 orthogonal measurements. Relative to such a set, we define a MUB-balanced state to be a pure state for which the list of probabilities of the d outcomes of any of these measurements is independent of the choice of measurement, up to permutations. In this paper, we explicitly construct a MUB-balanced state for each prime power dimension d for which d = 3 (mod 4). These states have already been constructed by Appleby in unpublished notes, but our presentation here is different in that both the expression for the states themselves and the proof of MUB-balancedness are given in terms of the discrete Wigner function, rather than the density matrix or state vector. The discrete Wigner functions of these states are “rotationally symmetric” in a sense roughly analogous to the rotational symmetry of the energy eigenstates of a harmonic oscillator in the continuous two-dimensional phase space. Upon converting the Wigner function to a density matrix, we find that the states are expressible as real state vectors in the standard basis. We observe numerically that when d is large (and not a power of 3), a histogram of the components of such a state vector appears to form a semicircular distribution.
A vorticity dynamics view of “effective slip boundary” with application to foil-flow control
Authors: Zhu J. Y. , Zhu F. L. , Su W. D. , Zou S. F. , Liu L. Q. , Shi Y. P. , Wu J. Z.
Published: December 2014

Effective slip boundary (ESB) formed on textured surfaces provides a very promising method to control complex separated flow. It is becoming technically feasible due to the rapid development of new materials and other innovative technologies. In this paper, we explore the underlying physical mechanisms and guiding principle of this new control strategy by theory of boundary vorticity dynamics. We illustrate the theory by a numerical study of using textured surface to control separated foil-flow. Unlike traditional control strategy working on existing boundary layers, this new strategy aims at weakening or even eliminating the boundary layer itself by manipulating its origin. Significant ESB control effects are observed on suppressing separation, enhancing lift, and reducing drag at stall angle of attack.
Extensions of Hamiltonian systems dependent on a rational parameter
Authors: Chanu Claudia Maria , Degiovanni Luca , Rastelli Giovanni
Published: December 2014

The technique of “extension” allows to build (d + 2)-dimensional Hamiltonian systems with a non-trivial polynomial in the momenta first integral of any given degree starting from a suitable d-dimensional Hamiltonian. Until now, the application of the technique was restricted to integer values of a certain fundamental parameter determining the degree of the additional first integral. In this article, we show how the technique of extension can be generalized to any rational value of the same parameter. Several examples are given, among them the two uncoupled oscillators and a special case of the Tremblay-Turbiner-Winternitz system.
Decay rate estimates for a class of quasilinear hyperbolic equations with damping terms involving p-Laplacian
Authors: Wu Yuhu , Xue Xiaoping
Published: December 2014

In this paper, we are concerned with the asymptotic behaviour of weak solutions to the initial boundary value problem for a class of quasilinear hyperbolic equations with damping terms involving p-Laplacian. By using the multiplier methods, we investigate the stability of weak solutions to the initial boundary value problem and obtain explicit decay rate estimation depending on strain-caused stress term and damping terms.
Increased InAs quantum dot size and density using bismuth as a surfactant
Authors: Dasika Vaishno D. , Krivoy E. M. , Nair H. P. , Maddox S. J. , Park K. W. , Jung D. , Lee M. L. , Yu E. T. , Bank S. R.
Published: December 2014

We have investigated the growth of self-assembled InAs quantum dots using bismuth as a surfactant to control the dot size and density. We find that the bismuth surfactant increases the quantum dot density, size, and uniformity, enabling the extension of the emission wavelength with increasing InAs deposition without a concomitant reduction in dot density. We show that these effects are due to bismuth acting as a reactive surfactant to kinetically suppress the surface adatom mobility. This mechanism for controlling quantum dot density and size has the potential to extend the operating wavelength and enhance the performance of various optoelectronic devices.
Experimental study of the application of micro-PIV on the flow characteristics detection of micro-gap rotational flow field
Authors: Tang Fei , Wang Chunze , Shi Yupeng , Wang Xiaohao
Published: December 2014

For a micro-gap rotational flow field with a large horizontal extent, tiny gap and fast flow velocity, the two-dimensional images shot by the micro-scale Particle ImageVelocimetry(Micro-PIV) technique are not sufficient for the study of local or whole flow characteristics. In this paper, by establishing a test bench of a rotational flow field with the functions of driving, positioning, adjustment and sensing, all the local states of the micro-gap rotational flow field can be obtained by horizontally moving the rotating axis to observe point by point. While measuring some local flow fields, two-dimensional pictures are taken by adjusting the focusing height of the objective lens, and then superposed and interpolated according to their shooting order to obtain a quasi-three-dimensional distribution image of the local flow fields, thus obtaining the flow condition of the vertical section of the flow field. The position of the focusing plane and mutual distance are adjusted to realize the measurement of wall shear force in the flow field, providing a feasible reference method for detecting the rheological property of the gap flow field and the effect of surface drag reduction.
Improved optogalvanic detection with voltage biased Langmuir probes
Authors: Persson A. , Berglund M. , Salehpour M.
Published: December 2014

Optogalvanic detectors show great potential for infrared spectroscopy, especially in cavity enhanced techniques where they, in contrast to ordinary absorption detectors, can perform intracavity measurements. This enables them to utilize the signal-to-noise ratio improvement gained from the extended effective path length inside an optical cavity, without losing signal strength due to the limited amount of light exiting through the rear mirror. However, if optogalvanic detectors are to become truly competitive, their intrinsic sensitivity and stability has to be improved. This, in turn, requires a better understanding of the mechanisms behind the generation of the optogalvanic signal. The study presented here focuses on an optogalvanic detector based on a miniaturized stripline split-ring resonator plasma source equipped with Langmuir probes for detecting the optogalvanic signal. In particular, the effect of applying a constant bias voltage to one of the probes is investigated, both with respect to the sensitivity and stability, and to the mechanism behind the generation of the signal. Experiments with different bias voltages at different pressures and gas composition have been conducted. In particular, two different gas compositions (pure CO2 and 0.25% CO2 in 99.75% N2) at six different pressures (100 Pa to 600 Pa) have been studied. It has been shown that probe biasing effectively improves the performance of the detector, by increasing the amplitude of the signal linearly over one order of magnitude, and the stability by about 40% compared with previous studies. Furthermore, it has been shown that relatively straightforward plasma theory can be applied to interpret the mechanism behind the generation of the signal, although additional mechanisms, such as rovibrational excitation from electron-molecule collisions, become apparent in CO2 plasmas with electron energies in the 1–6 eV range. With the achieved performance improvement and the more solid theoretical framework presented here, stripline split-ring resonator optogalvanic detectors can evolve into a compact, inexpensive, and easy-to-operate alternative for future infrared spectrometers.
Development and experimental characterization of a wall-less Hall thruster
Authors: Mazouffre S. , Tsikata S. , Vaudolon J.
Published: December 2014

An alternative Hall thruster architecture that shifts the ionization and acceleration regions outside the plasma chamber is demonstrated. This unconventional design is here termed a “wall-less Hall thruster,” as the bulk of the magnetized discharge is no longer limited by solid boundaries. A 200 W prototype with permanent magnets has been developed and characterized. Experimental results concerning the thruster operation, discharge oscillations, electric field distribution, and ionization zone characteristics are presented and discussed. Our first experiments show that the cross-field discharge can be moved outside the cavity without drastically disturbing the ion production and acceleration mechanisms. This design offers the benefit of reduced plasma-wall interaction and lower wall losses, while also greatly facilitating diagnostic access to the entire discharge ionization and acceleration regions.
Photon-enhanced thermionic emission from p-GaAs with nonequilibrium Cs overlayers
Authors: Zhuravlev A. G. , Romanov A. S. , Alperovich V. L.
Published: December 2014

Photon-enhanced thermionic emission (PETE), which is promising for increasing the efficiency of solar energy conversion, is studied during cesium deposition on the As- and Ga-rich p-GaAs(001) surfaces and subsequent relaxation in the nonequilibrium Cs overlayer by means of photoemission quantum yield spectroscopy adapted for systems with time-variable parameters. Along with direct photoemission of “hot” electrons excited by light above the vacuum level, the spectra contain PETE contribution of “thermalized” electrons, which are excited below the vacuum level and emit in vacuum due to thermalization up in energy by phonon absorption. Comparing the measured and calculated spectra, the effective electron affinity and escape probabilities of hot and thermalized electrons are obtained as functions of submonolayer Cs coverage. The minima in the affinity and pronounced peaks in the escape probabilities are observed for Cs deposition on both the As- and Ga-rich surfaces. Possible reasons for the low mean values of the electron escape probabilities and for the observed enhancement of the probabilities at certain Cs coverages are discussed, along with the implications for the PETE device realization.
Nano-batteries in a carry fluid as power supply: Freeform geometry, superfast refilling, and heat self-dissipation
Authors: Liu Guangyu , Powell Patrick , Lu Wei
Published: December 2014

This letter proposes and analyzes a system composed of many micro- or nano-scale batteries. Each battery is a self-contained Li-ion micro-battery enclosed in an insulating shell, and can charge/ discharge wirelessly or through contacts. Thousands of such batteries are carried by an inert fluid to form a power fluid to drive an electric vehicle. This power fluid can be stored in the tank and replaced easily with a fully charged fluid by refilling once its energy is depleted. The system can provide better energy density, higher power density, and extremely fast “charging” within minutes. The architecture eliminates the large over-capacity design in the current battery packs, significantly reducing the weight and cost. It would also enable progressive improvements of vehicle performance by replacing the micro-batteries. The battery system has flexible geometry, and therefore can essentially go into a storage space of any geometry, allowing uniform design of battery configurations for diverse applications.
Field induced modification of defect complexes in magnesium-doped lithium niobate
Authors: Meyer Nadège , Nataf Guillaume F. , Granzow Torsten
Published: December 2014

Dielectric constant, thermally stimulated depolarization currents (TSDC), and conductivity of undoped and 5% Mg-doped LiNbO3 single crystals between −100 °C and 200 °C have been investigated. A Debye-like dielectric relaxation with an activation energy of 135 meV is observed in the Mg-doped material, but not in undoped crystals. On heating this relaxation disappears near 140 °C and does not reappear after cooling. Anomalies observed in TSDC around this temperature are attributed to the motion of lithium vacancies, in agreement with conductivity measurements. It is proposed that in thermal equilibrium the electrons from the MgLi• donors are trapped in (4MgLi•+4VLi′) defect complexes. High-temperature poling breaks these defect complexes. The transition of the liberated electrons between the MgLi• donor centers and the NbNb forming the conduction band gives rise to the observed dielectric relaxation.
Evolution of iron-containing defects during processing of Si solar cells
Authors: Mchedlidze Teimuraz , Möller Christian , Lauer Kevin , Weber Jörg
Published: December 2014

The formation of iron-containing defects was studied during the fabrication process of a Si solar cell. Three Cz-Si crystals with different iron content in the feedstock were grown for the study. Iron-containing defects in and near-to the n+p-junction volume (NJV) of the cells are formed directly after phosphorus diffusion due to an inflow of iron atoms from the dissolving iron-silicide precipitates. These NJV-defects strongly affect the dark saturation current of the junctions. Partial dissolution or gettering of the NJV-defects during formation of the antireflection coating is accompanied by an increase in defect concentrations in the bulk of the cell. Further deterioration of bulk carrier lifetime during the formation of electrical contacts is related to the partial dissolution of remaining iron-silicide precipitates during the firing process. A general description of the defect evolution in iron-contaminated wafers during solar cell processing is presented and possible strategies for reducing the influence of iron-containing defects are proposed.
Embeded photonic crystal at the interface of p-GaN and Ag reflector to improve light extraction of GaN-based flip-chip light-emitting diode
Authors: Zhen Aigong , Ma Ping , Zhang Yonghui , Guo Enqing , Tian Yingdong , Liu Boting , Guo Shikuan , Shan Liang , Wang Junxi , Li Jinmin
Published: December 2014

In this experiment, a flip-chip light-emitting diode with photonic crystal was fabricated at the interface of p-GaN and Ag reflector via nanospheres lithography technique. In this structure, photonic crystal could couple with the guide-light efficiently by reason of the little distance between photonic crystal and active region. The light output power of light emitting diode with embedded photonic crystal was 1.42 times larger than that of planar flip-chip light-emitting diode. Moreover, the embedded photonic crystal structure makes the far-field divergence angle decreased by 18° without spectra shift. The three-dimensional finite difference time domain simulation results show that photonic crystal could improve the light extraction, and enhance the light absorption caused by Ag reflector simultaneously, because of the roughed surface. The depth of photonic crystal is the key parameter affecting the light extraction and absorption. Light extraction efficiency increases with the depth photonic crystal structure rapidly, and reaches the maximum at the depth 80 nm, beyond which light extraction decrease drastically.
Design tunable materials: Ferroelectric-antiferroelectric composite with core-shell structure
Authors: Curecheriu Lavinia-Petronela , Buscaglia Maria Teresa , Maglia Filippo , Anselmi-Tamburini Umberto , Buscaglia Vincenzo , Mitoseriu Liliana
Published: December 2014

Permittivity, tunability, and ferroelectric properties can be tailored to meet specific requirements for applications by combining ferroelectric (BaTiO3-BT) and antiferroelectric (La0.04Pb0.96Ti0.1Zr0.9O3-PLZT) and by exploiting interdiffusion and grain size effects at nanoscale. The dielectric properties, dc-tunability, and P(E) loops of ferroelectric-antiferroelectric nanostructured composites produced from mechanically mixed powders (PLZT-BT) and from core-shell particles (PLZT@BT) were comparatively analyzed. Interdiffusion accompanied by local composition gradients occurred during sintering of PLZT@BT composites and caused a thermally stable permittivity. Permittivity was reduced below 1000 in both cases (900 for PLZT-BT and 290 for PLZT@BT), while preserving tunability to 1.2–1.4 (E = 40 kV/cm), with a linear field dependence.
Micro rectennas: Brownian ratchets for thermal-energy harvesting
Authors: Pan Y. , Powell C. V. , Song A. M. , Balocco C.
Published: December 2014

We experimentally demonstrated the operation of a rectenna for harvesting thermal (blackbody) radiation and converting it into dc electric power. The device integrates an ultrafast rectifier, the self-switching nanodiode, with a wideband log-periodic spiral microantenna. The radiation from the thermal source drives the rectenna out of thermal equilibrium, permitting the rectification of the excess thermal fluctuations from the antenna. The power conversion efficiency increases with the source temperatures up to 0.02% at 973 K. The low efficiency is attributed mainly to the impedance mismatch between antenna and rectifier, and partially to the large field of view of the antenna. Our device not only opens a potential solution for harvesting thermal energy but also provides a platform for experimenting with Brownian ratchets.
Estimating the heat transfer to an organic soil surface during crown fire
Authors: Thompson D. K. , Wotton B. M. , Waddington J. M.
Published: December 2014

The Peatland Smouldering and Ignition (PSI) model was developed to quantify the heat transfer from a wildfire to an organic soil or moss surface in a Sphagnum–black spruce peatland. The Canadian Fire Behaviour Prediction system was used as a basis for the relationship between wind speed and rate of spread. Convection, conduction, and radiation processes were modelled before and during the arrival of the flaming front. The net heat flux to the soil from fire varied between 1.1 and 8.6 MJ m–2, with moderate-intensity fires transferring more energy to the surface compared with higher-intensity fires under higher winds. Radiative heat transfer to the soil surface both before the fire’s arrival and within the flaming front were the primary mechanisms of energy gain to the peatland surface. The role of convective and conductive cooling was no greater than 30% of gross energy gain. Peatland surface ignition in hummock and hollow microforms was modelled under normal and drought conditions. Hollow microforms dried out significantly during the course of a summer and increased their ignition vulnerability. Small-scale changes in slope and aspect of the peatland surface increased the amount of heat transferred by radiation by up to 30%, allowing some areas of higher soil moisture content to ignite. While no direct model validation is available, model outputs showing the preferential combustion of lichen and feathermoss, and the lack of ignition in Sphagnum in all but the most severe drought generally mimic observed ignitions patterns. The modelled peak of net energy input to the surface occurred at moderate wind speeds, suggesting that high-intensity fires do not necessarily lead to greater energy transfer and risk of smouldering combustion.
Foraging behaviour of the endangered Australian skink (Liopholis slateri)
Authors: McKinney Megan A. , Schlesinger Christine A. , Pavey Chris R.
Published: December 2014

The foraging behaviour of the endangered Australian skink (Liopholis slateri) was investigated through detailed observation of a subpopulation of lizards during seven months of sampling. Slater’s skinks primarily exhibited ambush predation, darting from burrow entrances to distances of up to 4 m with a success rate of ~70%. The direction of darting was often straight ahead and almost always in an 180° arc in front of the burrow entrance. Juveniles foraged more frequently and further from burrows than adults. Ants were the most common prey item taken and juveniles targeted small ants as prey more often than adults and often moved further to capture these prey. The spread of introduced buffel grass (Cenchrus ciliaris) in central Australia in recent decades is a possible contributing factor to the decline of L. slateri. A wide field of view appears to be critical for the success of the sit-and-wait foraging strategy employed by the skinks and additional research is required to determine whether further encroachment of buffel grass around burrow systems will impede visibility and directly affect foraging behaviour of these skinks.
Avian influenza H5N1 viral and bird migration networks in Asia
Authors: Tian Huaiyu , Zhou Sen , Dong Lu , Van Boeckel Thomas P. , Cui Yujun , Newman Scott H. , Takekawa John Y. , Prosser Diann J. , Xiao Xiangming , Wu Yarong , Cazelles Bernard , Huang Shanqian , Yang Ruifu , Grenfell Bryan T. , Xu Bing
Published: December 2014

Significance

Highly pathogenic avian influenza virus H5N1 first emerged in Asia and subsequently unfolded into the first avian influenza panzootic, causing major economic losses in the poultry sector. However, we still do not understand the regional long-distance transmission and seasonal patterns of H5N1. In this study, we addressed this issue by combining H5N1 outbreak records, whole-genome sequences of viral samples, and satellite tracking data for four species of migratory birds in Asia. We show that timing of H5N1 outbreaks and viral migration are closely associated with known bird migration routes. The flyway is the major viral transmission barrier to the intracontinental spread of H5N1 by migratory birds in Asia, whereas geographic distances within the flyways have little effect on H5N1 transmission.
TAp73 opposes tumor angiogenesis by promoting hypoxia-inducible factor 1α degradation
Authors: Amelio Ivano , Inoue Satoshi , Markert Elke K. , Levine Arnold J. , Knight Richard A. , Mak Tak W. , Melino Gerry
Published: December 2014

Significance

Adaptation to hypoxia promotes cancer progression, resulting in enhanced patient mortality. Activation of hypoxia-inducible factor 1 (HIF-1) leads to a transcriptional switch, which, regulating angiogenesis, metabolism, and survival, results in hypoxia adaptation. In cancer, increased HIF-1 levels can be a result of either intratumoral hypoxia or the altered function of tumor suppressors. Our study demonstrates that the tumor suppressor TAp73, a member of the p53 family of genes, opposes HIF-1 activation in cancer cells, resulting in reduced angiogenesis and tumor progression. TAp73-depleted mice show increased tumorigenicity, associated with increased HIF-1 signaling and angiogenesis. Expression of TAp73 in human cancers predicts good survival outcome and retrocorrelates with HIF-1 expression and activation. The TAp73/HIF-1 axis plays a critical role in cancer pathogenesis.
Recent origin of low trabecular bone density in modern humans
Authors: Chirchir Habiba , Kivell Tracy L. , Ruff Christopher B. , Hublin Jean-Jacques , Carlson Kristian J. , Zipfel Bernhard , Richmond Brian G.
Published: December 2014

Significance

The human skeleton is unique in having low trabecular density representing a lightly built human body form. However, it remains unknown when during human evolution this unique characteristic first appeared. To our knowledge, this study is the first to examine trabecular bone density throughout the skeleton of fossil hominins spanning several million years. The results show that trabecular density remained high throughout human evolution until it decreased significantly in recent modern humans, suggesting a possible link between changes in our skeleton and increased sedentism.
Multifarious assembly mixtures: Systems allowing retrieval of diverse stored structures
Authors: Murugan Arvind , Zeravcic Zorana , Brenner Michael P. , Leibler Stanislas
Published: December 2014

Significance

Self-assembly has recently emerged as a powerful technique for synthesizing structures on the nano- and microscales. The basis of this development is the use of biopolymers, like DNA, to design specific interactions between multiple species of components, allowing the spontaneous assembly of complex structures. Our work addresses a fundamental limitation of the existing approaches to self-assembly: Namely, every target structure must have its own dedicated set of components, which are programmed to assemble only that very structure. In contrast, in biological systems, the same set of components can assemble many different complexes. Inspired by this, we extend the self-assembly framework to mixtures of shared components capable of assembling distinct structures on demand.
Influenza viral neuraminidase primes bacterial coinfection through TGF-β–mediated expression of host cell receptors
Authors: Li Ning , Ren Aihui , Wang Xiaoshuang , Fan Xin , Zhao Yong , Gao George F. , Cleary Patrick , Wang Beinan
Published: December 2014

Significance

Pneumonia caused by bacterial coinfection with influenza virus is the leading cause of mortality in influenza pandemics. TGF-β is known to be activated by influenza virus. In this study we demonstrated that cellular adhesins for bacteria, such as fibronectin and α5 integrin, are up-regulated in influenza viral infection. Inhibition of TGF-β impeded the up-regulation of these cellular adhesins and also influenza viral-enhanced bacterial adherence. In addition, we found that influenza viral-promoted bacterial adherence was dependent on bacterial fibronectin-binding protein. The results indicate that up-regulated expression of cellular adhesins by TGF-β, which is activated in influenza viral infection, increases host susceptibility to bacterial coinfection and suggest that TGF-β and host adhesion molecules are potential pharmaceutical targets for prevention of coinfection.
Pan-vertebrate comparative genomics unmasks retrovirus macroevolution
Authors: Hayward Alexander , Cornwallis Charlie K. , Jern Patric
Published: December 2014

Significance

For millions of years retroviruses, such as HIV in humans, have attacked vertebrates. Occasionally retroviruses infiltrate germ cells, incorporate themselves into the host’s genome, and transmit vertically to the host’s offspring as endogenous retroviruses (ERVs). Consequently, ERVs make up large portions of vertebrate genomes and represent a record of past host–retrovirus interactions. We developed pan-vertebrate ERV analyses to provide an overview of host–retrovirus interactions, generating insights into retroviral evolution, diversity, host-switching, and the factors influencing retroviral transmission. Astoundingly, we found over 36,000 ERV lineages across our sample of vertebrate diversity. The results provide knowledge about host–retrovirus coevolution, suggesting an unprecedented ability of retroviruses to switch between distantly related vertebrates and implying existence of additional, yet unidentified retroviruses.
HDAC inhibition imparts beneficial transgenerational effects in Huntington's disease mice via altered DNA and histone methylation
Authors: Jia Haiqun , Morris Charles D. , Williams Roy M. , Loring Jeanne F. , Thomas Elizabeth A.
Published: December 2014

Significance

We demonstrate that histone deacetylase (HDAC) inhibition can elicit changes in DNA methylation in Huntington’s disease (HD) human fibroblasts, as well as in sperm from HD transgenic mice, in association with DNA methylation-related gene expression changes. We suggest that alterations in sperm DNA methylation lead to transgenerational effects, and, accordingly, we show that first filial generation (F1) offspring of HDAC inhibitor-treated male HD transgenic mice show improved HD disease phenotypes compared with F1 offspring from vehicle-treated male HD transgenic mice. These findings have significant implications for human health because they enforce the concept that ancestral drug exposure may be a major molecular factor that can affect disease phenotypes, yet in a positive manner. Further, we implicate Lys (K)-specific demethylase 5d expression in this phenomenon.
Patterns of genome evolution that have accompanied host adaptation in
Salmonella
Authors: Langridge Gemma C. , Fookes Maria , Connor Thomas R. , Feltwell Theresa , Feasey Nicholas , Parsons Bryony N. , Seth-Smith Helena M. B. , Barquist Lars , Stedman Anna , Humphrey Tom , Wigley Paul , Peters Sarah E. , Maskell Duncan J. , Corander Jukka , Chabalgoity Jose A. , Barrow Paul , Parkhill Julian , Dougan Gordon , Thomson Nicholas R.
Published: December 2014

Significance

Common features have been observed in the genome sequences of bacterial pathogens that infect few hosts. These “host adaptations” include the acquisition of pathogenicity islands of multiple genes involved in disease, losses of whole genes, and even single mutations that affect gene function. Within
Salmonella enterica
is a natural model system of four pathogens that are each other’s closest relatives, including a host-generalist, two host-specialists, and one with strong host associations. With whole-genome sequences, we aimed to improve our understanding of the number, nature, and order of these host adaptation events, shedding light on how human and animal pathogens arose in the past, and potentially allowing us to predict how emerging pathogens will evolve in the future.
Evening use of light-emitting eReaders negatively affects sleep, circadian timing, and next-morning alertness
Authors: Chang Anne-Marie , Aeschbach Daniel , Duffy Jeanne F. , Czeisler Charles A.
Published: December 2014

Significance

The use of light-emitting electronic devices for reading, communication, and entertainment has greatly increased recently. We found that the use of these devices before bedtime prolongs the time it takes to fall asleep, delays the circadian clock, suppresses levels of the sleep-promoting hormone melatonin, reduces the amount and delays the timing of REM sleep, and reduces alertness the following morning. Use of light-emitting devices immediately before bedtime also increases alertness at that time, which may lead users to delay bedtime at home. Overall, we found that the use of portable light-emitting devices immediately before bedtime has biological effects that may perpetuate sleep deficiency and disrupt circadian rhythms, both of which can have adverse impacts on performance, health, and safety.
Evolutionary pattern in the OXT-OXTR system in primates: Coevolution and positive selection footprints
Authors: Vargas-Pinilla Pedro , Paixão-Côrtes Vanessa Rodrigues , Paré Pamela , Tovo-Rodrigues Luciana , Vieira Carlos Meton de Alencar Gadelha , Xavier Agatha , Comas David , Pissinatti Alcides , Sinigaglia Marialva , Rigo Maurício Menegatti , Vieira Gustavo Fioravanti , Lucion Aldo B. , Salzano Francisco Mauro , Bortolini Maria Cátira
Published: December 2014

Significance

It was previously believed that placental mammals present no variability in oxytocin (OXT). The present study reports novel data on the diversity of
OXT
and its receptor (
OXTR
) in primate species, including New World monkeys. Contrary to prior expectations, we found three novel OXT forms and several OXTR nonsynonymous changes not previously described. In the Cebidae family, signals of positive selection were found for an OXT variant at position 8, which is associated with larger litter sizes. We detected positive selection for OXTR forms and report a coevolutionary process between changes in OXT and OXTR.
Rare allele of a previously unidentified histone H4 acetyltransferase enhances grain weight, yield, and plant biomass in rice
Authors: Song Xian Jun , Kuroha Takeshi , Ayano Madoka , Furuta Tomoyuki , Nagai Keisuke , Komeda Norio , Segami Shuhei , Miura Kotaro , Ogawa Daisuke , Kamura Takumi , Suzuki Takamasa , Higashiyama Tetsuya , Yamasaki Masanori , Mori Hitoshi , Inukai Yoshiaki , Wu Jianzhong , Kitano Hidemi , Sakakibara Hitoshi , Jacobsen Steven E. , Ashikari Motoyuki
Published: December 2014

Significance

Grain weight is an important crop yield component; however, its underlying regulatory mechanisms are largely unknown. Here, we identify a grain-weight quantitative trait locus (QTL) in rice encoding a new-type GNAT-like protein that harbors intrinsic histone acetyltransferase activity (OsglHAT1). Elevated OsglHAT1 expression enhances grain weight and yield by enlarging spikelet hulls via increasing cell number and accelerating grain filling, and increases global acetylation levels of histone H4. Our findings reveal the first example, to our knowledge, of a QTL for a yield component trait being due to a chromatin modifier that has the potential to improve crop high-yield breeding.