bluuebunny/crossref_metadata_2025 huggingface dataset:
Mechanistic insight into the hydroxylation of alkanes by a nonheme iron(v)–oxo complex
Authors: Kwon Eunji , Cho Kyung-Bin , Hong Seungwoo , Nam Wonwoo
Published: April 2014

The alkane hydroxylation by a mononuclear nonheme iron(v)–oxo complex occurs via a hydrogen-atom abstraction–oxygen non-rebound mechanism.
Inter/intramolecular Cherenkov radiation energy transfer (CRET) from a fluorophore with a built-in radionuclide
Authors: Bernhard Yann , Collin Bertrand , Decréau Richard A.
Published: April 2014

Some radionuclides emit optical light, the Cherenkov radiation (CR, i.e. the blue glow in nuclear reactors), which activates fluorophores.
Recyclable chemosensor for oxalate based on bimetallic complexes of a dinucleating bis(iminopyridine) ligand
Authors: Beattie J. W. , White D. S. , Bheemaraju A. , Martin P. D. , Groysman S.
Published: April 2014

We describe bimetallic complexes of a flexible dinucleating bis(iminopyridine) ligand that bind oxalate intramolecularly. Oxalate coordination is reversed by CaBr2.
Electronegativity effects and single covalent bond lengths of molecules in the gas phase
Authors: Lang Peter F. , Smith Barry C.
Published: April 2014

This paper discusses in detail the calculation of internuclear distances of heteronuclear single bond covalent molecules in the gaseous state.
Pneumatic valves in folded 2D and 3D fluidic devices made from plastic films and tapes
Authors: Cooksey Gregory A. , Atencia Javier
Published: April 2014

Elastomeric valves integrated into foldable microfluidic devices built with tapes.
Twin-driven thermoelectric figure-of-merit enhancement of Bi2Te3 nanowires
Authors: Shin Ho Sun , Jeon Seong Gi , Yu Jin , Kim Yong-Sung , Park Hyun Min , Song Jae Yong
Published: April 2014

Thermoelectric figure-of-merits (ZT) are enhanced or degraded by crystal defects such as twins and excess atoms that are correlated with thermal conductivity (k) and carrier concentration (n).
An oligonucleotide-based label-free luminescent switch-on probe for RNA detection utilizing a G-quadruplex-selective iridium(iii) complex
Authors: Ma Dik-Lung , Lin Sheng , Leung Ka-Ho , Zhong Hai-Jing , Liu Li-Juan , Chan Daniel Shiu-Hin , Bourdoncle Anne , Mergny Jean-Louis , Wang Hui-Min David , Leung Chung-Hang
Published: April 2014

We herein constructed an oligonucleotide-based luminescent RNA detection platform by using a novel G-quadruplex-selective luminescent iridium(iii) complex.
Covalently functionalized carbon nanotube supported Pd nanoparticles for catalytic reduction of 4-nitrophenol
Authors: Gu Xianmo , Qi Wei , Xu Xianzhu , Sun Zhenhua , Zhang Liyun , Liu Wei , Pan Xiaoli , Su Dangsheng
Published: April 2014

Carbon nanotubes (CNTs) were covalently functionalized via 1,3-dipolar cycloaddition reaction under microwave conditions. Then Pd nanoparticle/CNT nanocomposites were fabricated through strong electronic adsorption and H2 reduction, which exhibited high catalytic activity.
Fabrication of well-defined electromagnetic Fe3O4/polyaniline hollow microspheres and their application in Pb2+ uptake
Authors: Wang Feng , Huang Liyan , Li Jun , Lin Lina , Liu Zhengping , Dong Zhaoxia
Published: April 2014

Magnetic polyaniline hollow spheres with the functionality of lead uptake were fabricated by using citric acid to decorate ferroferric oxide.
Trienamine catalysis with linear deconjugated 3,5-dienones
Authors: Chen Peng-Qiao , Xiao You-Cai , Yue Cai-Zhen , Chen Ying-Chun
Published: April 2014

Deconjugated linear 3,5-dienones with substantial substitutions were used in β,ε-regioselective Diels–Alder cycloadditions with 3-olefinic oxindoles via trienamine catalysis of cinchona-based primary amines.
Polyurethane microcapsules for self-healing paint coatings
Authors: Koh Eunjoo , Kim Nam-Kyun , Shin Jihoon , Kim Young-Wun
Published: April 2014

Polyurethane microcapsules containing water-borne polyurethane (PU) paint as a core material for self-repairing protection coatings were successfully manufactured via interfacial polymerization of diol–diisocyanate prepolymer and 1,4-butanediol as a chain extender in an emulsion solution.
Topochemical synthesis of Bi2O3 microribbons derived from a bismuth oxalate precursor as high-performance lithium-ion batteries
Authors: Wang Hai , Yang Hongxing , Lu Lin
Published: April 2014

A one-dimensional inorganic arrangement in the bismuth oxalate hydroxide Bi(C2O4)OH was directly transformed into bismuth oxide Bi2O3via a simple thermal decomposition without a morphology change.
Characterization of a P2-type chelating-agent-assisted Na2/3Fe1/2Mn1/2O2 cathode material for sodium-ion batteries
Authors: Park Kwangjin , Han Dongwook , Kim Hyunjin , Chang Won-seok , Choi Byungjin , Anass Benayad , Lee Seoksoo
Published: April 2014

A chelating-agent-assisted Na2/3Fe1/2Mn1/2O2 material showed enhanced electrochemical performance due to the formation of a thin and stable solid-electrolyte interface layer.
Deprotonation mechanism of a single-stranded DNA i-motif
Authors: Smiatek Jens , Heuer Andreas
Published: April 2014

An atomistic Molecular Dynamics simulation to study the unfolding and deprotonation mechanism of a single-stranded and fully protonated DNA i-motif.
On the non-additivity of the substituent effect in ortho-, meta- and para-homo-disubstituted benzenes
Authors: Hęclik K. , Dębska B. , Dobrowolski J. Cz.
Published: April 2014

The non-additivity of the substituent effect inpara-,meta-, andortho- homo-disubstituted benzenes on π-valence orbitals is smaller than that on σ-ones. The former increases while the latter decreases with π-electron-donating character of the substituent which demonstrates the role of hyperconjugation in the substituent effect.
A polymer-based SERS-active substrate with gyroid-structured gold multibranches
Authors: Hsueh Han-Yu , Chen Hung-Ying , Ling Yi-Chun , Huang Wei-Shiang , Hung Yu-Chueh , Gwo Shangjr , Ho Rong-Ming
Published: April 2014

A 3D SERS-active substrate synthesized using a hydrolyzed PS-PLLA as a template for gyroid-structured Au multibranches with sharp tips and corners was used to detect crystal violet and β-carotene with superior sensitivity and high reproducibility and stability.
Investigation into the role of the hydrogen bonding network in cyclodextrin-based self-assembling mesophases
Authors: Ward Sandra , Calderon Oliver , Zhang Ping , Sobchuk Matthew , Keller Samantha N. , Williams Vance E. , Ling Chang-Chun
Published: April 2014

The ability to form self-organized thermotropic mesophases of amphiphilic cyclodextrins correlates well with their ability to establish an intermolecular H-bond network.
Win–win relationship between macrocell and femtocells for spectrum sharing in LTE‐A
Authors: Hamouda Soumaya , Zitoun Monia , Tabbane Sami
Published: April 2014

Heterogeneous networks (HetNets) are likely to provide a ubiquitous access to the mobile broadband services as they involve various small cells, each targeting a different environment in the network. However, the application of the advanced resource allocation techniques is highly needed in order to handle the inter‐cell interference and fully exploit the benefits of such networks. In this study, the authors address the spectrum sharing problem in a HetNet composed of a macrocell and several femtocells. They propose a new approach in which macrocell and femtocells can simultaneously share the available bandwidth, while avoiding the intra‐tier interference and helping the macrocell to offload by expanding the cell range of some femtocells. The author's approach is formulated as a Stackelberg game, in which the macrocell is selling bandwidths to femtocells in exchange of some victim macro‐users to serve, mainly the macro‐users who undergo severe interference from the neighbouring femtocells. They demonstrated that their game theoretic reaches a stable state called Stackelberg equilibrium analytically and by simulations. More importantly, they show that overall network performance is improved in terms of total femtocells’ throughputs and spectral efficiency of the macro‐users who are in the vicinity of the femtocells.
Wide baseline stereo matching based on scale invariant feature transformation with hybrid geometric constraints
Authors: Yang Huachao , Yu Mei , Zhang Shubi
Published: April 2014

Wide baseline stereo matching is a challenging task because of the presence of significant geometric deformations and illumination changes within the images. Based on the scale invariant feature transformation (SIFT) algorithm, this study proposes a new hybrid matching scheme that uses both the feature‐based and the area‐based methods to find reliable matches from sparse to dense under different geometric constraints. Firstly, the authors propose a SIFT‐based robust weighted least squares matching (LSM) method modelled by a two‐dimensional (2D) projective transformation to establish the initial correspondences and their local homographies. In this method, a normalised cross correlation metric modified with an adaptive scale and an orientation of the SIFT features (SIFT‐NCC) is proposed to find a good initial alignment for the SIFT‐LSM. Secondly, a robust matching propagation using the SIFT‐NCC starts from the initial matches under an epipolar geometry and the local homography constraints; geometrical consistency checking is used simultaneously to identify the false matches. Thirdly, they use an improved, feature‐based SIFT matching method to find the correspondences from the points that are not coplanar in the 3D space under an epipolar constraint only. A bidirectional selection strategy is used to remove the error matches.
Dynamic simulation of eccentric squirrel cage induction motors by including saturable reluctances of individual teeth
Authors: Ojaghi Mansour , Nasiri Samaneh
Published: April 2014

This study proposes an analytic model for three‐phase squirrel cage induction motors (SCIMs) under general eccentricity fault with variable degree, including static, dynamic and mixed eccentricities. After defining general air gap function, the air gap length within each slot pitch is assumed to be constant and equal to its length at the centre of the slot pitch by approximation. Then, by using modified winding function theory, analytic equations are obtained for the motor inductances. A novel technique is introduced to calculate saturable reluctances of individual teeth in every simulation step. These reluctances are added to the model by proper increment of the air gap length in front of each tooth. Consequently, dynamic simulation of SCIMs with any eccentricity type and degree and with the effect of the teeth saturable reluctances is made possible in the frame of a single Matlab code. It is shown that by adding the teeth reluctances, the amplitudes of the side‐band harmonics around the fundamental line current, as the eccentricity fault indices, are reduced towards the corresponding harmonic amplitudes obtained by experiments. Finally, the proposed method is extended to include axial asymmetries.
Stochastic scenario‐based model and investigating size of energy storages for PEM‐fuel cell unit commitment of micro‐grid considering profitable strategies
Authors: Mohammadi Sirus , Mozafari Babak , Solymani Soodabe , Niknam Taher
Published: April 2014

This paper presents a unit commitment formulation for micro‐grid that includes a significant number of grid parallel Proton Exchange Membrane‐Fuel Cell Power Plants (PEM‐FCPPs) with ramping rate and minimum up/down time constraints. The aim of this problem is to determine the optimum size of energy storage like battery storages and use the efficient hydrogen and thermal energy storages and to schedule the committed units' output power while satisfying practical constraints and electrical/thermal load demand over one day with 15 min time step. In order to best use of multiple PEM‐FCPPs, hydrogen storage management is carried out. Also, since the electrical and heat load demand are not synchronised, it could be useful to store the extra heat of PEM‐FCPPs in the peak electrical load in order to satisfy delayed heat demands. Due to uncertainty nature of electrical/thermal load, photovoltaic and wind turbine output power and market price, a two‐stage scenario‐based stochastic programming model, where the first stage prescribes the here‐and‐now variables and the second stage determines the optima value of wait‐and‐see variables under cost minimization is implemented. For solving the problem, a new enhanced cuckoo optimisation algorithm is presented and successfully applied to two typical micro‐grids. Quantitative results show its usefulness.
Event‐based remedial action scheme against super‐component contingencies to avert frequency and voltage instabilities
Authors: Derafshian Maram Mehdi , Amjady Nima
Published: April 2014

Frequency instability, voltage instability or a combination of both have been the cause of several power system breakdowns throughout the world in the recent decades. Occurrence of a super‐component contingency (SCC) that refers to multiple and simultaneous outages of grid facilities like a power plant or substation may lead to blackout if no remedial action schemes (RAS) are implemented. This study proposes a new event‐based RAS to overcome the frequency and voltage instabilities caused by SCCs through optimal load shedding. To do this, a new multi‐objective framework is presented simultaneously optimising the competing objective functions of long‐term voltage stability margin, steady‐state frequency deviation, maximum transient frequency deviation and load shed amount. A modified system frequency response model is also proposed for frequency stability assessment. Multi‐objective decision making (MODM) is performed using a combination of analytical hierarchy process, modified augmented ε‐constraint method and technique for order preference by similarity to ideal solution. The effectiveness of both the proposed model and MODM solution approach is extensively illustrated on a simulated model of Iran's power system in 2012.
Edge detection for illumination varying images using wavelet similarity
Authors: Swaminathan Anand , Ramapackiyam Shantha Selva Kumari
Published: April 2014

This study presents a new method of edge detection (ED) in illumination varying images. The undesirable dependence because of uneven illumination is crucial in image ED. The proposed algorithm avoids this problem by incorporating a new weighted least‐square regularisation with the wavelet filter directional responses. In order to obtain the edge information, the similarity between image neighbourhood pixels and wavelet filter is measured. This new method accomplishes the benefits of wavelets, which includes multi‐scale, and wider design choice in the filter length. Figure of merit (F) and structural similarity index qualitatively compares its performances. The subjective and objective results describes that this algorithm performs better than other methods.
Robust multilane detection and tracking in urban scenarios based on LIDAR and mono‐vision
Authors: Cui Guangtao , Wang Junzheng , Li Jing
Published: April 2014

Lane detection and tracking is the basic component of many intelligent vehicle systems. In this study, a robust multilane detection and tracking method is proposed. Using the measurements provided by an in‐vehicle mono‐camera and a forward‐looking LIDAR, this algorithm can address challenging scenarios in real urban driving situations. The proposed approach makes use of steerable filters for lane feature detection, LIDAR‐based image drivable space segmentation for lane marking points validations and the RANdom SAmple Consensus technique for robust lane model fitting. To improve the robustness of the fitting further, the parallel lanes hypothesis is introduced. The detected lanes initialise particle filters for tracking, without knowing the ego‐motion information. The image processing procedures are carried out in inverse perspective mapping image, because of its convenience for multilane detection. Experimental results indicate that the algorithm in this study has robustness against various driving situations.
Detection of partially occluded pedestrians by an enhanced cascade detector
Authors: Li Wenhui , Ni Hongyin , Wang Ying , Fu Bo , Liu Peixun , Wang Shoujia
Published: April 2014

Pedestrian detection occupies a vital status in the field of computer vision because of its important applications such as intelligent surveillance system, intelligent transport system, robotics and automotive safety. To improve the algorithm performance for pedestrian detection, and especially to cope with the partial occlusion problem, a novel pedestrian detection framework is presented based on the improved adaptive boosting (Adaboost) algorithm and enhanced cascade detector output. There are three major contributions. First, aiming to solve the drawbacks of the conventional Adaboost method, a modified Adaboost algorithm is proposed for more accurate detecting pedestrian. Second, a simple yet effective way is proposed, called local area marking map (LAMM), to decide whether the partial occlusion occurs in a detection window. At last, in order to handle the partial occlusion problem, an enhanced cascade scheme is derived from the LAMM information. Additionally, the histograms of oriented gradients features are combined with the proposed framework. The authors validate the significant improvements of the proposed method by extensive experiments testing on Institut National de Recherche en Informatique et en Automatique (INRIA), Daimler, by performance evaluation of tracking and by surveillance 2001 (PETS'2001) datasets with comparisons to several state‐of‐the‐art methods.
Reliability comparison of transmit/receive diversity and error control coding in low‐power medium access control protocols
Authors: Ghamari Mohammad , Momahed Heravi Behzad , Roedig Utz , Honary Bahram
Published: April 2014

Low‐power medium access control (MAC) protocols used for communication of energy constraint wireless embedded devices do not cope well with situations where transmission channels are highly erroneous. Existing MAC protocols discard corrupted messages which lead to costly retransmissions. To improve transmission performance, it is possible to include an error correction scheme and transmit/receive diversity. It is possible to add redundant information to transmitted packets in order to recover data from corrupted packets. It is also possible to make use of transmit/receive diversity via multiple antennas to improve error resiliency of transmissions. Both schemes may be used in conjunction to further improve the performance. In this study, the authors show how an error correction scheme and transmit/receive diversity can be integrated in low‐power MAC protocols. Furthermore, the authors investigate the achievable performance gains of both methods. This is important as both methods have associated costs (processing requirements; additional antennas and power) and for a given communication situation it must be decided which methods should be employed. The authors’ results show that, in many practical situations, error control coding outperforms transmission diversity; however, if very high reliability is required, it is useful to employ both schemes together.
Characterisation of InAs/GaAs quantum dots intermediate band photovoltaic devices
Authors: Garduño‐Nolasco Edson , Carrington Peter J. , Krier Anthony , Missous Mohamed
Published: April 2014

The authors report on the structural, the optical and the electrical properties of solar cells containing 20 layers of doped InAs/GaAs quantum dots (QDs). The structures were grown by molecular beam epitaxy and contain n dopant sheet densities of 8 and 16 × 1010 cm−2, respectively, in between the QD layers. Under a 1 sun illumination, the open‐circuit voltage (Voc) and the efficiency of the 8 × 1010 cm−2 n‐doped sample were increased to values of 0.73 V and 9.7%, respectively, compared with a reference undoped sample (a Voc of 0.70 V and an efficiency of 9.0%). However, the short‐circuit current density (Jsc) decreased from 20.1 to 17.4 mA/cm2 indicating bandfilling within the QD array.
Theoretical study of line narrowing in a sub‐terahertz monolithic dual laser source with an integrated reflector
Authors: Yang Zhen , Wonfor Adrian , Penty Richard V. , White Ian H.
Published: April 2014

A monolithic design is proposed for low‐noise sub‐THz signal generation by integrating a reflector onto a dual laser source. The reflectivity and the position of such a reflector can be adjusted to obtain constructive feedback from the reflector to both lasers, thus causing a Vernier feedback effect. As a result, 10‐fold line narrowing, the narrowing being limited by the resolution of the simulation, is predicted using a transmission line model. Finally, a simple control scheme using an electrical feedback loop to adjust laser biases is proposed to maintain the line narrowing performance. This line narrowing technique, comprising a passive integrated reflector, could allow the development of a low‐cost, compact and energy‐efficient solution for high‐purity sub‐THz signal generation.
Electronic and thermoelectric properties of few-layer transition metal dichalcogenides
Authors: Wickramaratne Darshana , Zahid Ferdows , Lake Roger K.
Published: April 2014

The electronic and thermoelectric properties of one to four monolayers of MoS2, MoSe2, WS2, and WSe2 are calculated. For few layer thicknesses, the near degeneracies of the conduction band K and Σ valleys and the valence band Γ and K valleys enhance the n-type and p-type thermoelectric performance. The interlayer hybridization and energy level splitting determine how the number of modes within kBT of a valley minimum changes with layer thickness. In all cases, the maximum ZT coincides with the greatest near-degeneracy within kBT of the band edge that results in the sharpest turn-on of the density of modes. The thickness at which this maximum occurs is, in general, not a monolayer. The transition from few layers to bulk is discussed. Effective masses, energy gaps, power-factors, and ZT values are tabulated for all materials and layer thicknesses.
Mechanical energy dissipation induced by sloshing and wave breaking in a fully coupled angular motion system. II. Experimental investigation
Authors: Bouscasse B. , Colagrossi A. , Souto-Iglesias A. , Cercos-Pita J. L.
Published: April 2014

In Paper I of this series [B. Bouscasse, A. Colagrossi, A. Souto-Iglesias, and J. L. C. Pita, “Mechanical energy dissipation induced by sloshing and wave breaking in a fully coupled angular motion system. I. Theoretical formulation and numerical investigation,” Phys. Fluids 26, 033103 (2014)], a theoretical and numerical model for a driven pendulum filled with liquid was developed. The system was analyzed in the framework of tuned liquid dampers and hybrid mass liquid dampers (HMLD) theory. In this paper, in order to measure the energy dissipation resulting from shallow water sloshing, an experimental investigation is conducted. Accurate evaluations of energy transfers are obtained through the recorded kinematics of the system. A set of experiments is conducted with three different liquids: water, sunflower oil, and glycerine. Coherently with the results of Paper I, the energy dissipation obtained when the tank is filled with water can mainly be explained by the breaking waves. For all three liquids, the effects of varying the external excitation amplitude are discussed.
Fluorescent Mueller matrix analysis of a highly scattering turbid media
Authors: Satapathi Soumitra , Soni Jalpa , Ghosh Nirmalya
Published: April 2014

We report the fluorescent Mueller matrix analysis of a highly scattering, inhomogeneous, and low quantum yield polymeric nanoparticle system. Both the ground and the excited state anisotropy of this turbid system were measured. The excited state anisotropy was found to be higher than ground state anisotropy by inverse polar decomposition analysis. The depolarization coefficients of these polythiophene nanoparticles were experimentally determined by recording Mueller matrices from this complex random medium. This approach provides an alternative method of determining optical characteristics of low quantum efficiency turbid system like fluorescently leveled tissue phantom.
Interfacial charge and strain effects on the ferroelectric behavior of epitaxial (001) PbTiO3 films on (110) DyScO3 substrates
Authors: Highland M. J. , Fong D. D. , Stephenson G. B. , Fister T. T. , Fuoss P. H. , Streiffer S. K. , Thompson Carol , Richard M.-I. , Eastman J. A.
Published: April 2014

In-situ synchrotron x-ray observations reveal that the ferroelectric behavior of epitaxial (001) PbTiO3 thin films grown on (110) DyScO3 substrates depends on both film thickness and interfacial electrical properties. A 92-nm-thick film was found to exhibit an a/c domain structure with a ferroelectric Curie temperature similar to that theoretically predicted based on the strain state. In contrast, 6-nm-thick films contained only c-oriented domains, and the ferroelectric behavior was found to depend strongly on the nature of the electrical boundary condition at the buried interface.
Graphene composite for improvement in the conversion efficiency of flexible poly 3-hexyl-thiophene:[6,6]-phenyl C71 butyric acid methyl ester polymer solar cells
Authors: Chauhan A. K. , Gusain Abhay , Jha P. , Koiry S. P. , Saxena Vibha , Veerender P. , Aswal D. K. , Gupta S. K.
Published: April 2014

The solution of thin graphene-sheets obtained from a simple ultrasonic exfoliation process was found to chemically interact with [6,6]-phenyl C71 butyric acid methyl ester (PCBM) molecules. The thinner graphene-sheets have significantly altered the positions of highest occupied molecular orbital and lowest unoccupied molecular orbital of PCBM, which is beneficial for the enhancement of the open circuit voltage of the solar cells. Flexible bulk heterojunction solar cells fabricated using poly 3-hexylthiophene (P3HT):PCBM-graphene exhibited a power conversion efficiency of 2.51%, which is a ∼2-fold increase as compared to those fabricated using P3HT:PCBM. Inclusion of graphene-sheets not only improved the open-circuit voltage but also enhanced the short-circuit current density owing to an improved electron transport.
Communication: Comparing ab initio methods of obtaining effective U parameters for closed-shell materials
Authors: Yu Kuang , Carter Emily A.
Published: April 2014

The density functional theory (DFT)+U method is an efficient and effective way to calculate the ground-state properties of strongly correlated transition metal compounds, with the effective U parameters typically determined empirically. Two ab initio methods have been developed to compute the U parameter based on either constrained DFT (CDFT) or unrestricted Hartree-Fock (UHF) theory. Previous studies have demonstrated the success of both methods in typical open-shell materials such as FeO and NiO. In this Communication we report numerical instability issues that arise for the CDFT method when applied to closed-shell transition metals, by using ZnO and Cu2O as examples. By contrast, the UHF method behaves much more robustly for both closed- and open-shell materials, making it more suitable for treating closed-shell transition metals, as well as main group elements.
Plasmons in inhomogeneously doped neutral and charged graphene nanodisks
Authors: Silveiro Iván , Javier García de Abajo F.
Published: April 2014

We study plasmons in graphene nanodisks including the effect of inhomogeneity in the distribution of the doping charge. Specifically, we discuss the following two configurations: charged disks containing a fixed amount of additional carriers, which are self-consistently distributed along the surface to produce a uniform DC potential; and neutral disks exposed to a neighboring external point charge. A suitable finite-element method is elaborated to compute the charge density associated with the plasmons in the electrostatic limit. For charged disks, we find dipolar plasmons similar to those of uniformly doped graphene structures, in which the plasmon induced charge piles up near the edges. In contrast, in neutral disks placed near an external point charge, plasmons are strongly localized away from the edges. Surprisingly, a single external electron is enough to trap plasmons. The disks also display axially symmetric dark-plasmons, which can be excited through external illumination by coupling them to a neighboring metallic element. Our results have practical relevance for graphene nanophotonics under inhomogeneous doping conditions.
On the ion front of a plasma expanding into a vacuum
Authors: Allen J. E. , Perego M.
Published: April 2014

Calculations are reported on the expansion of a plasma into a vacuum, using a model of cold ions and Boltzmann electrons. The initial distribution of the ions at the edge of the plasma greatly affects the subsequent expansion. An initial abrupt drop of ion density leads to an expansion in which the abrupt drop is maintained. A finite slope, however, leads to the formation of a peak of ion density at the ion front. The subsequent behaviour may lead to wave breaking and the formation of multi-valued ion velocity distributions.
Investigation on edge fringing effect and oxide thickness dependence of inversion current in metal-oxide-semiconductor tunneling diodes with comb-shaped electrodes
Authors: Lin Chien-Chih , Hsu Pei-Lun , Lin Li , Hwu Jenn-Gwo
Published: April 2014

A particular edge-dependent inversion current behavior of metal-oxide-semiconductor (MOS) tunneling diodes was investigated utilizing square and comb-shaped electrodes. The inversion tunneling current exhibits the strong dependence on the tooth size of comb-shaped electrodes and oxide thickness. Detailed illustrations of current conduction mechanism are developed by simulation and experimental measurement results. It is found that the electron diffusion current and Schottky barrier height lowering for hole tunneling current both contribute on inversion current conduction. In MOS tunneling photodiode applications, the photoresponse can be improved by decreasing SiO2 thickness and using comb-shaped electrodes with smaller tooth spacing. Meantime, the high and steady photosensitivity can also be approached by introducing HfO2 into dielectric stacks.
Structural and thermodynamic properties of Fe1.12Te with multiple phase transitions
Authors: Cherian Dona , Rößler S. , Koz C. , Tsirlin A. A. , Schwarz U. , Wirth S. , Elizabeth Suja
Published: April 2014

The parent compound of iron chalcogenide superconductors, Fe1+yTe, with a range of excess Fe concentrations exhibits intriguing structural and magnetic properties. Here, the interplay of magnetic and structural properties of Fe1.12Te single crystals have been probed by low-temperature synchrotron X-ray powder diffraction, magnetization, and specific heat measurements. Thermodynamic measurements reveal two distinct phase transitions, considered unique to samples possessing excess Fe content in the range of 0.11≤y≤0.13. On cooling, an antiferromagnetic transition, TN≈57 K is observed. A closer examination of powder diffraction data suggests that the transition at TN is not purely magnetic, but accompanied by the commencement of a structural phase transition from tetragonal to orthorhombic symmetry. This is followed by a second prominent first-order structural transition at TS with TS<TN, where an onset of monoclinic distortion is observed. The results point to a strong magneto-structural coupling in this material.
Room-temperature ferromagnetism and optical properties in Mg-doped TiO2: A density functional theory investigation
Authors: Liu Yanyu , Zhou Wei , Wu Ping
Published: April 2014

The magnetic and optical properties of Mg-doped anatase TiO2 have been theoretically investigated using the LDA+U method. The total induced moments are about 2 μB, which mainly localize on the nearest apical oxygen atoms. Moreover, the hole-induced interactions indicate that the magnetic moments prefer to the ferromagnetic coupling with the antiferromagnetic state lying 1160 meV higher in energy. This implies that the ferromagnetic state can be stable against thermal fluctuations up to room temperature. Additionally, the Mg doping is able to enhance the absorption efficiency of solar spectrum, especially in the near-infrared light region, which origins from the isolated O 2p states above the valence-band maximum rather than the effect of band-gap narrowing.
Evaluation of the threshold trimming method for micro inertial fluidic switch based on electrowetting technology
Authors: Liu Tingting , Su Wei , Yang Tao , Han Bin
Published: April 2014

The switch based on electrowetting technology has the advantages of no moving part, low contact resistance, long life and adjustable acceleration threshold. The acceleration threshold of switch can be fine-tuned by adjusting the applied voltage. This paper is focused on the electrowetting properties of switch and the influence of microchannel structural parameters, applied voltage and droplet volume on acceleration threshold. In the presence of process errors of micro inertial fluidic switch and measuring errors of droplet volume, there is a deviation between test acceleration threshold and target acceleration threshold. Considering the process errors and measuring errors, worst-case analysis is used to analyze the influence of parameter tolerance on the acceleration threshold. Under worst-case condition the total acceleration threshold tolerance caused by various errors is 9.95%. The target acceleration threshold can be achieved by fine-tuning the applied voltage. The acceleration threshold trimming method of micro inertial fluidic switch is verified.
Probing the accelerating universe
Authors: Frieman Joshua
Published: April 2014

The Dark Energy Survey’s map of 200 million galaxies will help determine if cosmic acceleration is driven by a cosmological constant, by a new and dynamic form of energy, or by physics beyond the scope of general relativity.
Evaluating musical instruments
Authors: Campbell D. Murray
Published: April 2014

Scientific measurements of sound generation and radiation by musical instruments are surprisingly hard to correlate with the subtle and complex judgments of instrumental quality made by expert musicians.
Recolonisation of rabbit warrens following coordinated ripping programs in Victoria, south-eastern Australia
Authors: Ramsey D. S. L. , McPhee S. R. , Forsyth D. M. , Stuart I. G. , Scroggie M. P. , Lindeman M. , Matthews J.
Published: April 2014

Context Warren ripping has been demonstrated to be an effective tool for controlling rabbit populations. However, few studies have examined factors influencing the rate at which ripped warrens are likely to be recolonised (i.e. be re-opened). Aims To examine factors influencing the recolonisation of ripped warrens by rabbits by using data collected on 555 warrens for up to 15 years following coordinated ripping programs at 12 sites in Victoria, south-eastern Australia. Methods Warren-monitoring data (number of active and inactive warren entrances) were analysed using discrete-time survival analysis to determine the effects of warren-level and site-level covariates on the recolonisation of ripped warrens. Key results Warren recolonisation was related to the distance between the ripped warren and the nearest active warren, the number of active entrances in the nearest warren, the initial number of active entrances in the ripped warren and the rabbit spotlight abundance index at the site. The probability of warren recolonisation was highest for ripped warrens within 1 km of an active warren and negligible beyond 3 km. The probability of warren recolonisation also increased by 22% for every increase in the rabbit spotlight count at the site by 10 rabbits km–1. Conclusions The recolonisation of ripped warrens was highly influenced by both the distance to, and size of, neighbouring active warrens. Larger warrens also appear to be preferentially recolonised compared with smaller warrens, suggesting that recolonisation of ripped areas may be related to habitat quality. The present results are consistent with ideas from classical metapopulation theory predicting that the rates of colonisation of vacant patches are dependent on both the proximity and size of the source population as well as the quality of habitat patches. Implications Although coordinated warren ripping programs are effective at achieving long-term control of rabbits, their efficiency at maintaining low rabbit populations can be increased by adopting an adaptive monitoring program that incorporates warren size and the spatial relationships among warrens, and using this information to better target maintenance-control activities.
Climate change, pink salmon, and the nexus between bottom-up and top-down forcing in the subarctic Pacific Ocean and Bering Sea
Authors: Springer Alan M. , van Vliet Gus B.
Published: April 2014

Significance

Wild salmon in the North Pacific Ocean, particularly pink salmon, have grown greatly since the mid-1970s apparently due to bottom-up effects of climate change on ocean physics and production processes. Pink salmon spend less than 2 y at sea and most stocks alternate between high and low levels of abundance every other year. In years of high abundance, they now constitute a pelagic consumer front as they return to their spawning rivers, exert top-down control over the open ocean ecosystem by outcompeting other species for shared prey resources, and drive major ecological shifts between years of high and low abundance. Their effect on competing species must be considered in international conservation policies and when developing informed ecosystem-based management strategies.
Receptor revision in CD4 T cells is influenced by follicular helper T cell formation and germinal-center interactions
Authors: Higdon Lauren E. , Deets Katherine A. , Friesen Travis J. , Sze Kai-Yin , Fink Pamela J.
Published: April 2014

Significance

The diverse T-cell receptor (TCR) repertoire is generated by selection of T cells that have undergone TCR-gene recombination during intrathymic development. This process is precisely regulated to prevent DNA damage and to minimize the escape of self-reactive T cells. Peripheral T cells with self-reactive TCRs can be neutralized by undergoing further TCR-gene rearrangements, through a process known as TCR revision. Although a potentially useful source of new TCR specificities, revision incurs the risk of off-target DNA damage. Our work demonstrates that TCR revision occurs in the germinal center, a distinct microenvironment comprising specialized cells that engage in specific interactions. Confinement to this well-regulated environment may explain how a potentially risky process can occur safely.
Acentriolar mitosis activates a p53-dependent apoptosis pathway in the mouse embryo
Authors: Bazzi Hisham , Anderson Kathryn V.
Published: April 2014

Significance

Centrioles form the core of centrosomes, which organize cilia and interphase and spindle microtubules in animal cells, but centrosome function has not been defined in mammals in vivo. We show that mouse embryos that lack centrioles and centrosomes survive to midgestation, when they lack primary cilia and cilia-dependent signaling. Despite the absence of centrosomes, bipolar spindle formation, chromosome segregation, cell-cycle profile, and DNA damage response are normal in the mutants. Unlike mutants that lack cilia, most cells in acentriolar embryos activate a p53-dependent apoptotic pathway. The data show that mammalian centrioles promote the efficient and rapid assembly of the mitotic spindle and that a short delay in prometaphase activates a checkpoint that leads to p53-dependent cell death in vivo.
Cellular mechanisms for integral feedback in visually guided behavior
Authors: Schnell Bettina , Weir Peter T. , Roth Eatai , Fairhall Adrienne L. , Dickinson Michael H.
Published: April 2014

Significance

Visually driven behaviors of
Drosophila
have become a model system to study how neural circuits process sensory information. Here, we show that one of the computations performed by this system is temporal integration of visual motion. We provide evidence of how this computation might be performed by measuring the activity of identified visual interneurons during tethered flight that are thought to control the described behavior: Presynaptic calcium accumulation in these neurons mimics a leaky temporal integration of the visual motion signal as does the behavior. In the future, the genetic tools available in
Drosophila
will enable studying the precise mechanism of temporal integration in this model system, which could provide insights into general mechanisms of neuronal information processing.
Biomimetic engineered muscle with capacity for vascular integration and functional maturation in vivo
Authors: Juhas Mark , Engelmayr George C. , Fontanella Andrew N. , Palmer Gregory M. , Bursac Nenad
Published: April 2014

Significance

Engineering of highly functional skeletal muscle tissues can provide accurate models of muscle physiology and disease and aid treatment of various muscle disorders. Previous tissue-engineering efforts have fallen short of recreating structural and contractile properties of native muscle in vitro. Here, we describe the creation of biomimetic skeletal muscle tissues with structural, functional, and myogenic properties characteristic of native muscle and contractile stress values that surpass those of neonatal rat muscle. When implanted and real-time imaged in live animals, engineered muscle grafts undergo robust vascularization and perfusion, exhibit continued myogenesis, and show further improvements in intracellular calcium handling and contractile function. This process is significantly enhanced by myogenic predifferentiation and formation of aligned muscle architecture in vitro.
Quantification of HIV-1 latency reversal in resting CD4
+
T cells from patients on suppressive antiretroviral therapy
Authors: Cillo Anthony R. , Sobolewski Michele D. , Bosch Ronald J. , Fyne Elizabeth , Piatak Michael , Coffin John M. , Mellors John W.
Published: April 2014

Significance

A pool of latently infected resting CD4
+
T cells in patients on antiretroviral therapy is a major barrier to a cure for HIV-1. Clinical trials are underway to assess whether small molecules can “kick” HIV-1 out of latency, but the potency of such latency reversing agents has not been evaluated at the level of single proviruses. Using a unique quantitative system, we found that the histone deacetylase inhibitor vorinostat (suberoylanilide hydroxamic acid), which is being investigated clinically, did not induce unspliced cellular viral RNA or lead to virion production from the large majority of proviruses in resting CD4
+
T cells. Our results demonstrate that more potent interventions will likely be necessary to reduce the size of the latent reservoir.
Functional characterization of flavobacteria rhodopsins reveals a unique class of light-driven chloride pump in bacteria
Authors: Yoshizawa Susumu , Kumagai Yohei , Kim Hana , Ogura Yoshitoshi , Hayashi Tetsuya , Iwasaki Wataru , DeLong Edward F. , Kogure Kazuhiro
Published: April 2014

Significance

Ion-translocating, light-activated membrane proteins known as rhodopsins are found in all three domains of life. Proton-pumping rhodopsins, such as proteorhodopsin, are known to be broadly distributed in marine bacteria. The first known sodium-pumping rhodopsin was recently described in marine flavobacterium. We report the discovery and characterization of a unique type of light-activated ion-translocating rhodopsin that translocates chloride ions into the cell and is evolutionarily distinct from the other known rhodopsin chloride pump, halorhodopsin, found in haloarchaea. Our data show that rhodopsins with different ion specificities have evolved independently in marine bacteria, with individual strains containing as many as three functionally different rhodopsins.
Proteomic analysis of
Vibrio cholerae
outer membrane vesicles
Authors: Altindis Emrah , Fu Yang , Mekalanos John J.
Published: April 2014

Significance

Identifying proteins localized on the surface and envelope of Gram-negative bacterial cells is an important problem in vaccine development and antibiotic target discovery. We show that the characterization of proteins associated with outer membrane vesicles (OMVs) released by Gram-negative cells provides a solution in that contamination with abundant cytoplasmic proteins (caused by cell lysis) can be avoided. Integrated at a systems level with other transcription and proteomic data sets, our research provides a view of the surface architecture of a pathogen undergoing host-programmed changes in gene expression. Also provided is the first evidence to our knowledge that secreted protein-folding quality control (a property of the DegP protease) influences the composition of OMVs and bacterial virulence, validating DegP as a target for virulence-blocking drugs.
Lactococcosis in Silver Carp
Authors: Khoo Lester H. , Austin Frank W. , Quiniou Sylvie M. A. , Gaunt Patricia S. , Riecke Dennis K. , Jacobs Alicia M. , Meals Keith O. , Dunn Arthur W. , Griffin Matt J.
Published: April 2014

An adult Silver Carp Hypophthalmichthys molitrix with a focally extensive skin lesion near the caudal peduncle and mild iridial hemorrhage was submitted to the Aquatic Research and Diagnostic Laboratory (ARDL) in Stoneville, Mississippi, as part of a fish kill investigation. Touch impressions of this musculoskeletal lesion revealed small cocci (∼1 μm) in pairs or chains within an inflammatory milieu. A pure Gram-positive cocci isolate was obtained from the brain, while cultures of the kidney and muscle yielded multiple bacterial colony types, including the Gram-positive cocci seen in the brain. This brain isolate was characterized biochemically and identified as Lactococcus spp. Analysis of the near complete 16S small subunit ribosomal DNA (SSU rDNA) and DNA gyrase subunit B (gyrB) gene sequences revealed the bacterium to be L. lactis subsp. lactis (SSU rDNA: 100% identity, 1,372/1,372 bp; gyrB: 99.7% identity, 1,779/1,785 bp). Comparatively, at the gyrB locus the case isolate shared less than 90% similarity to L. lactis subsp. cremoris (1,599/1,781 bp) and less than 80% homology to L. garvieae (1409/1775 bp). Histopathological examination confirmed a severe meningoencephalitis, a moderate mononuclear myositis, and a mild interstitial nephritis. We believe this represents the first report of a natural infection by L. lactis subsp. lactis in Silver Carp.

Received December 3, 2012; accepted August 17, 2013
Molecular Characterization of the VP2 Gene of Infectious Pancreatic Necrosis Virus (IPNV) Isolates from Mexico
Authors: Salgado-Miranda Celene , Rojas-Anaya Edith , García-Espinosa Gary , Loza-Rubio Elizabeth
Published: April 2014

Infectious pancreatic necrosis virus (IPNV) is one of the most important viruses in the Pacific salmon Oncorhynchus spp., Atlantic Salmon Salmo salar, and Rainbow Trout O. mykiss industry. This virus has been shown to produce high mortality among salmonid fry and juveniles, and survivors might become carriers. Since 2000, IPNV has affected Mexican Rainbow Trout culture, resulting in considerable economic losses. In the current study, molecular characterization of the VP2 gene of a number of Mexican IPNV isolates was done and the virus's phylogenetic relationships to IPNV reference strains were investigated. The phylogenetic analysis indicated that Mexican IPNV isolates are closely related to strains from the United States and Canada and that all Mexican IPNV isolates belong to genogroup 1. Furthermore, low genetic diversity was found between the Mexican isolates (identity, 95.8–99.8% nucleotides and 95.8–99.6% aminoacids). The result of the analysis of the amino acid residues found at positions 217, 221, and 247 (alanine, threonine, and glutamic acid, respectively) could be associated with virulence, although the expression of virulence factors is more complex and may be influenced by the agent and host factors. The high percentage of identity among the VP2 genes from geographically distant IPNV isolates and the evidence of wide distribution in the country might have been facilitated by carrier trout. This hypothesis is supported by the identification of the amino acid threonine at position 221 in all Mexican isolates, a factor related to the carrier state for IPNV, as reported by other studies.

Received July 14, 2013; accepted October 24, 2013