bluuebunny/crossref_metadata_2025 huggingface dataset:
Optical response of a quantum dot–epoxy resin composite: effect of tensile strain
Authors: Yin Shaofeng , Zhao Ziming , Luan Weiling , Yang Fuqian
Published: February 2016

The structural applications of quantum dots (QDs) can be artificially realized through the preparation of QDs-based structural materials, which exhibit unique characteristics of photoluminescence (PL) in response to mechanical deformation.
Optimization of the process parameters for the adsorption of ternary dyes by Ni doped FeO(OH)-NWs–AC using response surface methodology and an artificial neural network
Authors: Azad Farshid Nasiri , Ghaedi Mehrorang , Asfaram Arash , Jamshidi Arsalan , Hassani Ghasem , Goudarzi Alireza , Azqhandi Mohammad Hossein Ahmadi , Ghaedi Abdolmohammad
Published: February 2016

The present study deals with the simultaneous removal of chrysoidine G (CG), rhodamine B (RB) and disulfine blue (DB) by Ni doped ferric oxyhydroxide FeO(OH) nanowires on activated carbon (Ni doped FeO(OH)-NWs–AC).
In situ calcium phosphate deposition in hydrogels of poly(acrylic acid)–polyacrylamide interpenetrating polymer networks
Authors: Simeonov M. S. , Apostolov A. A. , Vassileva E. D.
Published: February 2016

Interpenetrating networks of poly(acrylic acid) and polyacrylamide were used for the first time as templates for in situ calcium phosphate (CP) deposition in an attempt to mimic the naturally occurring biomineralization.
Synthesis and in vivo stability studies of [18F]-zwitterionic phosphonium aryltrifluoroborate/indomethacin conjugates
Authors: Chansaenpak Kantapat , Wang Mengzhe , Liu Shuanglong , Wu Zhanhong , Yuan Hong , Conti Peter S. , Li Zibo , Gabbaï François P.
Published: February 2016

Conjugation ofortho-phosphonium phenyltrifluoroborates with indomethacin affords conjugates which have been radiolabeled by18F–19F isotopic exchange in aqueous solutions and imaged by positron emission tomography in mice.
Novel multi-stimuli responsive molecules based on photochromic bithienylethenes containing the tetrathiafulvalene unit
Authors: Zhang Jingyi , Sun Bingbing , Wang Qiaochun , Zou Lei
Published: February 2016

Two novel photochromic bisthienylethenes (BTEs) containing the tetrathiafulvalene (TTF) unit have been prepared, which exhibit good photoelectric properties.
A porous CuO nanowire-based signal amplification immunosensor for the detection of carcinoembryonic antigens
Authors: Feng Taotao , Qiao Xiuwen , Wang Haining , Sun Zhao , Qi Yu , Hong Chenglin
Published: February 2016

A novel electrochemical immunosensor was developed for the detection of CEA based on CNTs–AuNPs as a platform and pCuOw@Fc as labels. The immunosensor showed enhanced electrochemical performance toward the detection of CEA.
Galvanic replacement of electrodeposited nickel by palladium and investigation of the electrocatalytic activity of synthesized Pd/(Ni) for hydrogen evolution and formic acid oxidation
Authors: Rasouli Hassanali , Tabaian Seyed Hadi , Rezaei Milad
Published: February 2016

Highly active Pd/(Ni) catalysts were synthesized by well controlled galvanic replacement of electrodeposited nickel, towards hydrogen evolution and FA oxidation.
Tyrosinase-catalyzed polymerization of l-DOPA (versusl-tyrosine and dopamine) to generate melanin-like biomaterials for immobilization of enzymes and amperometric biosensing
Authors: Dai Mengzhen , Huang Ting , Chao Long , Tan Yueming , Chen Chao , Meng Wenhua , Xie Qingji
Published: February 2016

The tyrosinase-catalyzed polymerization of l-DOPA (versusl-tyrosine and dopamine) is recommended as an excellent system to immobilize enzymes for amperometric biosensing of catechol and glucose.
Electronic and magnetic properties of n-type and p-doped MoS2 monolayers
Authors: Zhao Xu , Chen Peng , Xia Congxin , Wang Tianxing , Dai Xianqi
Published: February 2016

The electronic and magnetic properties of n- and p-type impurities by means of group V and VII atoms substituting sulfur in a MoS2 monolayer were investigated using first-principles methods based on density functional theory.
Bandgap engineering of MoS2/MX2 (MX2 = WS2, MoSe2 and WSe2) heterobilayers subjected to biaxial strain and normal compressive strain
Authors: Su Xiangying , Ju Weiwei , Zhang Ruizhi , Guo Chongfeng , Zheng Jiming , Yong Yongliang , Li Xiaohong
Published: February 2016

Among MoS2/MX2 heterobilayers only the MoS2/WSe2 system exhibits a direct bandgap, and strain can be used to tune the direct bandgap character of the MoS2/MoSe2 and MoS2/WSe2 heterobilayers.
Efficient oxygen reduction reaction electrocatalysts synthesized from an iron-coordinated aromatic polymer framework
Authors: Zhao Yong , Kamiya Kazuhide , Hashimoto Kazuhito , Nakanishi Shuji
Published: February 2016

An iron-coordinated polymer (Fe(iii)–poly(o-phenylenediamine)) produced iron/nitrogen co-doped carbon electrocatalyst demonstrates highly efficient oxygen reduction reaction activity in both alkaline and acidic media.
Synergistic carbon nanotube aerogel – Pt nanocomposites toward enhanced energy conversion in dye-sensitized solar cells
Authors: Chen Haijun , Liu Tao , Ren Jing , He Hongcai , Cao Yonghai , Wang Ning , Guo Zhanhu
Published: February 2016

3-D carbon nanotube aerogels and their composites with Pt nanoparticles have shown enhanced solar energy conversion compared to regular CNTs.
Sensing a Bacillis anthracis biomarker with well-known OLED emitter EuTta3Phen
Authors: Shipman M. A. , Ramhit K. J. , Blight B. A.
Published: February 2016

Dipicolinic acid (DPA) is a distinctive biomarker for bacterial spores. Here, we present the successful demonstration of dramatic Switch-OFF sensing of DPA using an easily synthesised Eu(iii) phosphor applied primarily in light-emitting devices. The sensor shows excellent selectivites, and in the presence of water and phosphate is also demonstrated to be effective.
Dual-mode modulation of luminescence chromaticity in AgLa(MoO4)2:Yb3+,Ho3+up-conversion phosphors
Authors: Li Ting , Guo Chongfeng , Suo Hao , Zhao Puju
Published: February 2016

A series of Yb3+/Ho3+co-doped and Yb3+/Ho3+/Ce3+tri-doped AgLa(MoO4)2phosphors with green (542 nm) and red (660 nm) double color up-conversion (UC) emissions with 980 nm near-infrared (NIR) excitation were synthesized by a sol–gel process.
The impact of charge transfer and structural disorder on the thermoelectric properties of cobalt intercalated TiS2
Authors: Guélou Gabin , Vaqueiro Paz , Prado-Gonjal Jesús , Barbier Tristan , Hébert Sylvie , Guilmeau Emmanuel , Kockelmann Winfried , Powell Anthony V.
Published: February 2016

The thermoelectric figure of merit of TiS2 is increased by 25% through the intercalation of low levels of cobalt due to an increased electrical conductivity, arising from charge transfer, and a reduced thermal conductivity resulting from disorder.
Au nanoparticle decorated graphene nanosheets for electrochemical immunosensing of p53 antibodies for cancer prognosis
Authors: Elshafey Reda , Siaj Mohamed , Tavares Ana C.
Published: February 2016

Thiolated self-assembled reduced graphene oxide films were decorated with gold nanoparticles for development of a label-free p53-antibody immunosensor.
Comparison of design strategies for α-helix backbone modification in a protein tertiary fold
Authors: Tavenor Nathan A. , Reinert Zachary E. , Lengyel George A. , Griffith Brian D. , Horne W. Seth
Published: February 2016

Structural and thermodynamic analysis of a family of synthetic proteins with heterogeneous backbones yields new insights into the ability of unnatural amino acids to be accommodated into α-helices.
Distinguishing the roles of energy funnelling and delocalization in photosynthetic light harvesting
Authors: Baghbanzadeh Sima , Kassal Ivan
Published: February 2016

The contributions of energy funnelling and excitonic delocalization to the performance of photosynthetic complexes can be disentangled by comparing the performance of the natural complexes with models in which both the energy landscape and the delocalization are altered.
Ruthenium complexes bearing an unsymmetrical pincer ligand with a 2-hydroxypyridylmethylene fragment: active catalysts for transfer hydrogenation of ketones
Authors: Shi Jing , Hu Bowen , Gong Dawei , Shang Shu , Hou Guangfeng , Chen Dafa
Published: February 2016

The synthesis, reactivity and catalytic transfer hydrogenation activity of three metal–ligand cooperative ruthenium(ii) complexes (3–5) with a 2-hydroxypyridylmethylene fragment are reported.
U(v) in metal uranates: a combined experimental and theoretical study of MgUO4, CrUO4, and FeUO4
Authors: Guo Xiaofeng , Tiferet Eitan , Qi Liang , Solomon Jonathan M. , Lanzirotti Antonio , Newville Matthew , Engelhard Mark H. , Kukkadapu Ravi K. , Wu Di , Ilton Eugene S. , Asta Mark , Sutton Stephen R. , Xu Hongwu , Navrotsky Alexandra
Published: February 2016

Although pentavalent uranium can exist in aqueous solution, its presence in the solid state is uncommon.
Concurrent agostic and tetrel bonding interactions in lead(ii) complexes with an isonicotinohydrazide based ligand and several anions
Authors: Mahmoudi Ghodrat , Bauzá Antonio , Frontera Antonio
Published: February 2016

We report for the first time the concurrent agostic and tetrel bonding interactions involving the heaviest tetrel atom (Pb) in N′-(phenyl(pyridin-2-yl)methylene)isonicotinohydrazide–PbX complexes (X = Cl, I, NCS, NO2).
Novel strategies for the synthesis of unsymmetrical glycosyl disulfides
Authors: Morais Goreti Ribeiro , Springett Bradley R. , Pauze Martin , Schröder Lisa , Northrop Matthew , Falconer Robert A.
Published: February 2016

Novel strategies for the synthesis of sialosyl and glycosyl disulfides are reported.
Effects of interlayer coupling and electric fields on the electronic structures of graphene and MoS2heterobilayers
Authors: Hu Wei , Wang Tian , Zhang Ruiqi , Yang Jinlong
Published: February 2016

The effects of interlayer coupling and electric fields can be used to effectively control the Schottky barriers and contact formation at the interface of graphene and MoS2heterobilayers.
The anti-tumour agent lonidamine is a potent inhibitor of the mitochondrial pyruvate carrier and plasma membrane monocarboxylate transporters
Authors: Nancolas Bethany , Guo Lili , Zhou Rong , Nath Kavindra , Nelson David S. , Leeper Dennis B. , Blair Ian A. , Glickson Jerry D. , Halestrap Andrew P.
Published: February 2016

Lonidamine (LND) is an anti-tumour drug particularly effective at selectively sensitizing tumours to chemotherapy, hyperthermia and radiotherapy, although its precise mode of action remains unclear. It has been reported to perturb the bioenergetics of cells by inhibiting glycolysis and mitochondrial respiration, whereas indirect evidence suggests it may also inhibit L-lactic acid efflux from cells mediated by members of the proton-linked monocarboxylate transporter (MCT) family and also pyruvate uptake into the mitochondria by the mitochondrial pyruvate carrier (MPC). In the present study, we test these possibilities directly. We demonstrate that LND potently inhibits MPC activity in isolated rat liver mitochondria (Ki 2.5 μM) and co-operatively inhibits L-lactate transport by MCT1, MCT2 and MCT4 expressed in Xenopus laevis oocytes with K0.5 and Hill coefficient values of 36–40 μM and 1.65–1.85 respectively. In rat heart mitochondria LND inhibited the MPC with similar potency and uncoupled oxidation of pyruvate was inhibited more effectively (IC50 ∼ 7 μM) than other substrates including glutamate (IC50 ∼ 20 μM). In isolated DB-1 melanoma cells 1–10 μM LND increased L-lactate output, consistent with MPC inhibition, but higher concentrations (150 μM) decreased L-lactate output whereas increasing intracellular [L-lactate] > 5-fold, consistent with MCT inhibition. We conclude that MPC inhibition is the most sensitive anti-tumour target for LND, with additional inhibitory effects on MCT-mediated L-lactic acid efflux and glutamine/glutamate oxidation. Together these actions can account for published data on the selective tumour effects of LND on L-lactate, intracellular pH (pHi) and ATP levels that can be partially mimicked by the established MPC and MCT inhibitor α-cyano-4-hydroxycinnamate (CHC).
Flux‐based turn‐to‐turn fault protection for power transformers
Authors: Mostafaei Mohsen , Haghjoo Farhad
Published: February 2016

Since the internal turn‐to‐turn faults (TTFs), as a common cause of the transformer failures, result in minor changes on terminal currents/voltages, they maybe undetected by the conventional protective relays. In this study, a simple, sensitive and robust linkage flux‐based technique is proposed to protect the power transformers against TTFs. In this approach, some separated multi‐turn windings as search coils (SCs) have to be wrapped around the transformer core legs to sense the related passing flux. Since passing equal flux through a transformer core leg in normal condition induces equal voltages in the related SCs, variation of the induced voltages indicates the fault occurrence in that phase. Against the traditional differential protection schemes, current transformer error and saturation, tap changer operation, energising inrush current, over‐fluxing etc. cannot impact the proposed technique performance. Therefore, it can be introduced as a comprehensive protection technique for power transformers.To confirm the proposed technique performance, it is tested on a real 50 kVA, 20 kV/400 V three‐phase distribution transformer, in various conditions, too.
Optimisation of doubly periodic arrays of three‐dimensional metallic structures in free space and layered media
Authors: Basiri Raheleh , Abiri Habibollah , Yahaghi Alireza
Published: February 2016

In this study, doubly periodic arrays with three‐dimensional metallic inclusions in free space and multilayered media are studied. The random hill climbing (RHC) optimisation method is used to find optimal structures. Periodic method of moments (PMOMs) is applied to calculate the fitness functions of the resulted structures from RHC optimiser. The procedure which is proposed here for the optimisation of the structures may be used to design periodic sketches with arbitrary properties. The simulation results are compared with high‐frequency structure simulator computer‐aided design tool outcomes to verify the validity of the implemented PMOM code.
Multiband planar antenna for LTE/GSM/UMTS and WLAN/WiMAX handsets
Authors: Cui Yuehui , Yang Li , Liu Baiyang , Li RongLin
Published: February 2016

A multiband planar antenna is proposed for mobile handsets. The multiband antenna covers four frequency bands: 696–970 MHz for Long Term Evolution (LTE) 700, Global System for Mobile Communications (GSM) 850/900; 1683–2700 MHz for GSM 1800/1900, Universal Mobile Telecommunications System (UMTS) 2100, LTE 2300/2600, WLAN 2.4 GHz, WiMAX 2.5 GHz; 3070–3755 MHz for WiMAX 3.5 GHz; and 4590–7604 MHz for WLAN/WiMAX 5.2/5.8 GHz and WiMAX 5.5 GHz. The planar antenna consists of a U‐shaped monopole coupling with an S‐shaped strip, a clip‐shaped monopole with a meander line coupling with an inverted‐C strip, an X‐shaped monopole, and an F‐shaped monopole. The multiband antenna has a low profile and is printed on a thin substrate, suitable for ultra‐slim smartphone applications.
Overview of frequency diverse array in radar and navigation applications
Authors: Wang Wen‐Qin
Published: February 2016

Different from phased array providing only angle‐dependent transmit beampattern, frequency diverse array (FDA) employs a small frequency increment across its array elements to provide range–angle‐dependent transmit beampattern. This enables the array beam to scan without the need of phase shifters or mechanical steering. Since FDA has received much attention in antenna and radar signal processing societies, it is necessary to make an overview on this interesting topic. This study introduces what FDA is and why it could be exploited for radar and navigation applications from a top‐level system description and appeal to the radar signal processing and system engineering communities for more investigations on this promising array technique. The status of FDA studies is overviewed and the most recent advances of FDA radar are discussed. The basic FDA system architectures are introduced, along with performance compared to a conventional phased‐array. Next, guidelines for choosing good system parameters and typical implementation schemes are provided. Finally, potential applications in range and angle estimation of targets, cognitive FDA radar and low probability of identification FDA radar are discussed, along with several technical challenges.
Non‐parametric fault detection methods in non‐linear systems
Authors: Kowsari Elham , Safarinejadian Behrooz , Zarei Jafar
Published: February 2016

In this study, two fault detection methods are proposed for non‐linear systems. In these methods, Gaussian process (GP) is integrated into extended Kalman filter (EKF) and square root cubature Kalman filter (SCKF), which are called GP‐EKF and GP‐SCKF, respectively. The most important advantage of the proposed methods is that there is no need to know the accurate model of the system. Therefore, these methods are considered as non‐parametric approaches of fault detection in non‐linear systems. Moreover, by applying these methods, it is possible to detect the fault with high accuracy at early stage. First, GP‐EKF and GP‐SCKF are proposed for non‐linear state estimation, and then GP‐SCKF is compared with the GP‐EKF and the results of this comparison prove the superiority of GP‐SCKF regarding the complexity of computations and accuracy. In addition, simulation results show a good performance of GP‐EKF and GP‐SCKF in non‐linear system's fault detection. To illustrate performance of these algorithms in state estimation and fault detection, they are used in aircraft tracking system. Both of the proposed methods are able to detect the sensors faults at early stage.
Augmenting numerical stability of the Galerkin finite element formulation for electromagnetic flowmeter analysis
Authors: Subramanian Sethupathy , Kumar Udaya
Published: February 2016

Due to the complexities in handling liquid metals, theoretical evaluation of the sensitivity of magnetic flowmeters forms an attractive and preferred choice. The classical Galerkin finite element formulation is generally opted for the required evaluation. However, it is known to lead to numerical oscillations at higher flow rates. To overcome this, modified methods like upwind/Petrov–Galerkin schemes are generally suggested in allied areas like fluid dynamics. However, it requires the evaluation of stabilisation parameter and this parameter is not readily available for elements of order beyond quadratic. After a careful analysis of the numerical instability through a reduced one‐dimensional problem, an elegant and stable approach is devised. In this scheme, the input magnetic field is restated in terms of the associated vector potential and the classical Galerkin finite element method is employed without any modification. The analytical solution of the associated difference equation is employed to show: (i) the stability of the proposed approach at higher flow rates and (ii) quantification of the small oscillations remnant at intermediate flow rates. It is then applied to the original flowmeter problem and the stability of the numerical solution is clearly demonstrated.
Comparison of velocimetry techniques for turbulent structures in gas-puff imaging data
Authors: Sierchio J. M. , Cziegler I. , Terry J. L. , White A. E. , Zweben S. J.
Published: February 2016

Recent analysis of Gas Puff Imaging (GPI) data from Alcator C-Mod found blob velocities with a modified tracking time delay estimation (TDE). These results disagree with velocity analysis performed using direct Fourier methods. In this paper, the two analysis methods are compared. The implementations of these methods are explained, and direct comparisons using the same GPI data sets are presented to highlight the discrepancies in measured velocities. In order to understand the discrepancies, we present a code that generates synthetic sequences of images that mimic features of the experimental GPI images, with user-specified input values for structure (blob) size and velocity. This allows quantitative comparison of the TDE and Fourier analysis methods, which reveals their strengths and weaknesses. We found that the methods agree for structures of any size as long as all structures move at the same velocity and disagree when there is significant nonlinear dispersion or when structures appear to move in opposite directions. Direct Fourier methods used to extract poloidal velocities give incorrect results when there is a significant radial velocity component and are subject to the barber pole effect. Tracking TDE techniques give incorrect velocity measurements when there are features moving at significantly different speeds or in different directions within the same field of view. Finally, we discuss the limitations and appropriate use of each of methods and applications to the relationship between blob size and velocity.
Evaluating gambles using dynamics
Authors: Peters O. , Gell-Mann M.
Published: February 2016

Gambles are random variables that model possible changes in wealth. Classic decision theory transforms money into utility through a utility function and defines the value of a gamble as the expectation value of utility changes. Utility functions aim to capture individual psychological characteristics, but their generality limits predictive power. Expectation value maximizers are defined as rational in economics, but expectation values are only meaningful in the presence of ensembles or in systems with ergodic properties, whereas decision-makers have no access to ensembles, and the variables representing wealth in the usual growth models do not have the relevant ergodic properties. Simultaneously addressing the shortcomings of utility and those of expectations, we propose to evaluate gambles by averaging wealth growth over time. No utility function is needed, but a dynamic must be specified to compute time averages. Linear and logarithmic “utility functions” appear as transformations that generate ergodic observables for purely additive and purely multiplicative dynamics, respectively. We highlight inconsistencies throughout the development of decision theory, whose correction clarifies that our perspective is legitimate. These invalidate a commonly cited argument for bounded utility functions.
Enhanced instability of supersonic boundary layer using passive acoustic feedback
Authors: Tu Guohua , Hu Zhiwei , Sandham Neil D.
Published: February 2016

Tripping of boundary-layers from laminar to turbulent flow, which may be needed in specific practical applications, requires introducing high amplitude disturbances into the boundary layers without large drag penalties. As a possible improvement on fixed trip devices, a technique based on feedback instability is demonstrated in the present contribution for a Mach 1.5 boundary layer. The compressible Navier-Stokes equations are solved directly using a high-order (fifth-order in space and third-order in time) finite difference method. The geometries tested include wall-mounted rectangular blocks and off-surface cylinders. For a particular combination of an upstream cylinder and downstream block, a feedback loop is observed to provide more robust self-amplification of disturbances than a cylinder alone, whereas blocks by themselves only enhance a convective instability. A Fourier analysis and an impulse response simulation are used to confirm the presence of an acoustic feedback loop for the cylinder-block configuration. A parametric study of the size of the cylinder, the height, and the location of the rectangular block is also provided. It is observed that the feedback strength is not monotonically related to the height and location of the rectangular block.
Exploiting cellular convection in a thick liquid layer to pattern a thin polymer film
Authors: Nejati Iman , Dietzel Mathias , Hardt Steffen
Published: February 2016

A method to shape thin polymer films into periodic array of lenses is presented. A liquid layer placed on top of a much thinner polymer film is exposed to a transverse temperature gradient. The upper liquid layer undergoes the short-wavelength Bénard-Marangoni instability, which leads to periodic shear stresses at the liquid-liquid interface and corresponding interfacial deformations. The structures formed are solidified by curing with ultraviolet light. In comparison to previously reported single-layer patterning techniques, the presented method achieves structures of very high horizontal planform symmetry (highly ordered structures). Furthermore, other shapes of technical interest can be easily fabricated by engineering the temperature distribution at the liquid-gas interface.
Turbulent eddies in a compressible jet in crossflow measured using pulse-burst particle image velocimetry
Authors: Beresh Steven J. , Wagner Justin L. , Henfling John F. , Spillers Russell W. , Pruett Brian O. M.
Published: February 2016

Pulse-burst Particle Image Velocimetry (PIV) has been employed to acquire time-resolved data at 25 kHz of a supersonic jet exhausting into a subsonic compressible crossflow. Data were acquired along the windward boundary of the jet shear layer and used to identify turbulent eddies as they convect downstream in the far-field of the interaction. Eddies were found to have a tendency to occur in closely spaced counter-rotating pairs and are routinely observed in the PIV movies, but the variable orientation of these pairs makes them difficult to detect statistically. Correlated counter-rotating vortices are more strongly observed to pass by at a larger spacing, both leading and trailing the reference eddy. This indicates the paired nature of the turbulent eddies and the tendency for these pairs to recur at repeatable spacing. Velocity spectra reveal a peak at a frequency consistent with this larger spacing between shear-layer vortices rotating with identical sign. The spatial scale of these vortices appears similar to previous observations of compressible jets in crossflow. Super-sampled velocity spectra to 150 kHz reveal a power-law dependency of −5/3 in the inertial subrange as well as a −1 dependency at lower frequencies attributed to the scales of the dominant shear-layer eddies.
Feynman formulae and phase space Feynman path integrals for tau-quantization of some Lévy-Khintchine type Hamilton functions
Authors: Butko Yana A. , Grothaus Martin , Smolyanov Oleg G.
Published: February 2016

Evolution semigroups generated by pseudo-differential operators are considered. These operators are obtained by different (parameterized by a number τ) procedures of quantization from a certain class of functions (or symbols) defined on the phase space. This class contains Hamilton functions of particles with variable mass in magnetic and potential fields and more general symbols given by the Lévy-Khintchine formula. The considered semigroups are represented as limits of n-fold iterated integrals when n tends to infinity. Such representations are called Feynman formulae. Some of these representations are constructed with the help of another pseudo-differential operator, obtained by the same procedure of quantization; such representations are called Hamiltonian Feynman formulae. Some representations are based on integral operators with elementary kernels; these are called Lagrangian Feynman formulae. Langrangian Feynman formulae provide approximations of evolution semigroups, suitable for direct computations and numerical modeling of the corresponding dynamics. Hamiltonian Feynman formulae allow to represent the considered semigroups by means of Feynman path integrals. In the article, a family of phase space Feynman pseudomeasures corresponding to different procedures of quantization is introduced. The considered evolution semigroups are represented as phase space Feynman path integrals with respect to these Feynman pseudomeasures, i.e., different quantizations correspond to Feynman path integrals with the same integrand but with respect to different pseudomeasures. This answers Berezin’s problem of distinguishing a procedure of quantization on the language of Feynman path integrals. Moreover, the obtained Lagrangian Feynman formulae allow also to calculate these phase space Feynman path integrals and to connect them with some functional integrals with respect to probability measures.
Variational tensor approach for approximating the rare-event kinetics of macromolecular systems
Authors: Nüske Feliks , Schneider Reinhold , Vitalini Francesca , Noé Frank
Published: February 2016

Essential information about the stationary and slow kinetic properties of macromolecules is contained in the eigenvalues and eigenfunctions of the dynamical operator of the molecular dynamics. A recent variational formulation allows to optimally approximate these eigenvalues and eigenfunctions when a basis set for the eigenfunctions is provided. In this study, we propose that a suitable choice of basis functions is given by products of one-coordinate basis functions, which describe changes along internal molecular coordinates, such as dihedral angles or distances. A sparse tensor product approach is employed in order to avoid a combinatorial explosion of products, i.e., of the basis set size. Our results suggest that the high-dimensional eigenfunctions can be well approximated with relatively small basis set sizes.
Choice of computational method for swimming and pumping with nonslender helical filaments at low Reynolds number
Authors: Martindale J. D. , Jabbarzadeh M. , Fu H. C.
Published: February 2016

The flows induced by biological and artificial helical filaments are important to many possible applications including microscale swimming and pumping. Microscale helices can span a wide range of geometries, from thin bacterial flagella to thick helical bacterial cell bodies. While the proper choice of numerical method is critical for obtaining accurate results, there is little guidance about which method is optimal for a specified filament geometry. Here, using two physical scenarios — a swimmer with a head and a pump — we establish guidelines for the choice of numerical method based on helical radius, pitch, and filament thickness. For a range of helical geometries that encompass most natural and artificial helices, we create benchmark results using a surface distribution of regularized Stokeslets and then evaluate the accuracy of resistive force theory, slender body theory, and a centerline distribution of regularized Stokeslets. For the centerline distribution of regularized Stokeslets or slender body theory, we tabulate appropriate blob size and Stokeslet spacing or segment length, respectively, for each geometry studied. Finally, taking the computational cost of each method into account, we present the optimal choice of numerical method for each filament geometry as a guideline for future investigations involving filament-induced flows.
Three-dimensional single-mode nonlinear ablative Rayleigh-Taylor instability
Authors: Yan R. , Betti R. , Sanz J. , Aluie H. , Liu B. , Frank A.
Published: February 2016

The nonlinear evolution of the single-mode ablative Rayleigh-Taylor instability is studied in three dimensions. As the mode wavelength approaches the cutoff of the linear spectrum (short-wavelength modes), it is found that the three-dimensional (3D) terminal bubble velocity greatly exceeds both the two-dimensional (2D) value and the classical 3D bubble velocity. Unlike in 2D, the 3D short-wavelength bubble velocity does not saturate. The growing 3D bubble acceleration is driven by the unbounded accumulation of vorticity inside the bubble. The vorticity is transferred by mass ablation from the Rayleigh-Taylor spikes to the ablated plasma filling the bubble volume.
Particle trajectories in thermal counterflow of superfluid helium in a wide channel of square cross section
Authors: La Mantia Marco
Published: February 2016

The motion of micrometer-sized solid hydrogen particles in thermal counterflow of superfluid helium is studied experimentally by using the particle tracking velocimetry technique. The investigated quantum flow occurs in a square channel of 25 mm sides and 100 mm length, appreciably wider than those employed in previous related experiments. Flow velocities up to 10 mm/s are obtained, corresponding to temperatures between about 1.3 K and 2.1 K, and applied heat fluxes between ca. 50 W/m2 and 500 W/m2. The character of the obtained particle trajectories changes significantly as the imposed mean flow velocity increases. At thermal counterflow velocities lower than approximately 1 mm/s, the particle tracks appear straighter than at larger velocities. On the basis of the current understanding of the underlying physics, it is argued that the outcome is most likely due to the transition to the turbulent state of the investigated flow as, for narrower channels, this transition was reported to occur at larger velocities. The present results confirm that, at least in the parameter ranges investigated to date, the transition to turbulence in thermal counterflow depends on the geometry of the channel where this quantum flow develops.
Note: Optimal choice of the reflector by phase analysis for heterodyne interferometric roll angle measurement
Authors: Tang Shanzhi , Wang Zhao , Li Ming , Gao Junxiang , Jiang Yongcheng , Zhang Yao
Published: February 2016

The choice of an actual reflector instead of an ideal or perfect reflector has to be dealt with for heterodyne-interferometric roll angle measurement methods. The candidates of regular reflectors such as corner cube prism and right angle prism are analyzed by the homogeneous coordinate transformation method, which provides a theoretical basis for the determination of the actual reflector. Furthermore, the influences of the phase loss of the determined reflector are strictly argued due to non-perfect or natural characteristics itself. Several tactics are considered to solve this problem by phase analysis. By contrast, it is an optimal choice that mirrors-based right angle prism can improve evidently the phase loss by experiment.
No blow-up to a variational wave equation in liquid crystals
Authors: Huang Jingchi , Zheng Yuxi
Published: February 2016

We establish the global existence of smooth solutions to the Cauchy problem for a system of variational wave equations in one space dimension modeling a type of nematic liquid crystals that has equal splay and bend coefficients.
Growth and characterization of molecular beam epitaxy-grown Bi2Te3−xSex topological insulator alloys
Authors: Tung Y. , Chiang Y. F. , Chong C. W. , Deng Z. X. , Chen Y. C. , Huang J. C. A. , Cheng C.-M. , Pi T.-W. , Tsuei K.-D. , Li Z. , Qiu H.
Published: February 2016

We report a systematic study on the structural and electronic properties of Bi2Te3−xSex topological insulator alloy grown by molecular beam epitaxy (MBE). A mixing ratio of Bi2Se3 to Bi2Te3 was controlled by varying the Bi:Te:Se flux ratio. X-ray diffraction and Raman spectroscopy measurements indicate the high crystalline quality for the as-grown Bi2Te3−xSex films. Substitution of Te by Se is also revealed from both analyses. The surfaces of the films exhibit terrace-like quintuple layers and their size of the characteristic triangular terraces decreases monotonically with increasing Se content. However, the triangular terrace structure gradually recovers as the Se content further increases. Most importantly, the angle-resolved photoemission spectroscopy results provide evidence of single-Dirac-cone like surface states in which Bi2Te3−xSex with Se/Te-substitution leads to tunable surface states. Our results demonstrate that by fine-tuned MBE growth conditions, Bi2Te3−xSex thin film alloys with tunable topological surface states can be obtained, providing an excellent platform for exploring the novel device applications based on this compound.
Control of plasma properties in a short direct-current glow discharge with active boundaries
Authors: Adams S. F. , Demidov V. I. , Bogdanov E. A. , Koepke M. E. , Kudryavtsev A. A. , Kurlyandskaya I. P.
Published: February 2016

To demonstrate controlling electron/metastable density ratio and electron temperature by applying negative voltages to the active (conducting) discharge wall in a low-pressure plasma with nonlocal electron energy distribution function, modeling has been performed in a short (lacking the positive-column region) direct-current glow discharge with a cold cathode. The applied negative voltage can modify the trapping of the low-energy part of the energetic electrons that are emitted from the cathode sheath and that arise from the atomic and molecular processes in the plasma within the device volume. These electrons are responsible for heating the slow, thermal electrons, while production of slow electrons (ions) and metastable atoms is mostly due to the energetic electrons with higher energies. Increasing electron temperature results in increasing decay rate of slow, thermal electrons (ions), while decay rate of metastable atoms and production rates of slow electrons (ions) and metastable atoms practically are unchanged. The result is in the variation of electron/metastable density ratio and electron temperature with the variation of the wall negative voltage.
Design of plate directional heat transmission structure based on layered thermal metamaterials
Authors: Sun L. K. , Yu Z. F. , Huang J.
Published: February 2016

Invisibility cloaks based on transformation optics are often closed structures; however, such a structure limits the kinds of objects that can be placed in the cloak. In this work, we adopt a transformation thermodynamics approach to design an “open cloak”, called a plate directional heat transmission structure, which is capable of guiding heat fluxes to the flank region of the metamaterial device. The most fascinating and unique feature of the device is that the lower surface can remain at a lower temperature compared with the SiO2 aerogel thermal insulation material. Our results are expected to markedly enhance capabilities in thermal protection, thermal-energy utilization, and domains beyond. In addition to the theoretical analysis, the present design is demonstrated in numerical simulations based on finite element calculations.
The Julia Creek dunnart, Sminthopsis douglasi (Marsupialia : Dasyuridae): breeding of a threatened species in captivity and in wild populations
Authors: Woolley P. A.
Published: February 2016

A detailed description of the methods used to house, maintain and assess the reproductive condition of captive Julia Creek dunnarts, Sminthopsis douglasi, that led to successful breeding of the species in captivity is provided. Basic features of the reproductive biology of this species of Sminthopsis have been established from observations made on captive animals. The females are polyoestrous, with a cycle length of ~28 days. Young are born 13–16 days after mating and are dependent on the mother for ~70 days. The age at which captive animals commence breeding ranged from 13 to 38 weeks (females) and 23 to 40 weeks (males). Both sexes are capable of breeding when two years old. Breeding in wild populations is seasonal and occurs over a six-month period from August to March, which encompasses the hottest and wettest time of the year. Both females and males are known to be capable of breeding in more than one season and females have the potential to rear two litters in a season. Recruitment of young to the population may be affected by heavy rainfall during the breeding season that can lead to closure of the cracks and holes in which the dunnarts shelter.
Central auditory neurons have composite receptive fields
Authors: Kozlov Andrei S. , Gentner Timothy Q.
Published: February 2016

Significance

How neurons are selective for complex natural stimuli remains poorly understood, in part because standard statistical tools only identify one or two features of stimuli but not complete sets. Here, using a statistical method that overcomes these difficulties, we demonstrate that a set of multiple distinct acoustical features exists in individual auditory neurons in songbirds. We then use birdsongs to train an unsupervised neural network constrained by two common properties of biological neural circuits. The network rediscovers the same stimulus features observed in vivo. These results demonstrate that individual high-level auditory neurons respond not to single, but to multiple features of natural stimuli. This enables a robust, statistically optimal, representation of complex, real-world signals such as birdsong, speech, or music.
Polyclonal breast cancer metastases arise from collective dissemination of keratin 14-expressing tumor cell clusters
Authors: Cheung Kevin J. , Padmanaban Veena , Silvestri Vanesa , Schipper Koen , Cohen Joshua D. , Fairchild Amanda N. , Gorin Michael A. , Verdone James E. , Pienta Kenneth J. , Bader Joel S. , Ewald Andrew J.
Published: February 2016

Significance

Conventional models of cancer progression propose that single cells leave the primary tumor, enter the circulation, and seed clonal metastases. However, metastases can contain multiple clones, raising the question: How do polyclonal metastases form? We demonstrate that cancer cells seed distant organs as cohesive clusters, composed of two molecularly distinct subpopulations, whose proportions vary systematically during metastasis. We establish that collective dissemination is a frequent mechanism for metastasis and identify a molecular program in the most invasive, keratin 14
+
(K14
+
) cancer cells, regulating cell–cell adhesion, cell–matrix adhesion, and immune evasion. We demonstrate that this metastatic phenotype is dependent upon K14 expression. Understanding the molecular basis of collective dissemination may therefore enable novel prognostics and therapies to improve patient outcomes.
Tle1 tumor suppressor negatively regulates inflammation in vivo and modulates NF-κB inflammatory pathway
Authors: Ramasamy Selvi , Saez Borja , Mukhopadhyay Subhankar , Ding Daching , Ahmed Alwiya M. , Chen Xi , Pucci Ferdinando , Yamin Rae’e , Wang Jianfeng , Pittet Mikael J. , Kelleher Cassandra M. , Scadden David T. , Sweetser David A.
Published: February 2016

Significance

This study provides the first physiological evidence, to our knowledge, that Tle1 (transducin-like enhancer of split 1) is a major negative regulator of inflammation. We show that the loss of Tle1 in mice leads to increased activity of the proinflammatory NF-κB pathway as well as decreased activity of Hes1 (hairy and enhancer of split-1), a negative regulator of inflammation. In addition, Tle1 loss resulted in decreased growth and survival with increased myelopoiesis and lung hypoplasia. Loss of Tle1 also sensitized mice to inflammatory stimuli and facilitated cancer progression. Our study opens the way to further investigations for a role of Tle1 in human inflammatory disease and cancer progression.
Slip-mediated dewetting of polymer microdroplets
Authors: McGraw Joshua D. , Chan Tak Shing , Maurer Simon , Salez Thomas , Benzaquen Michael , Raphaël Elie , Brinkmann Martin , Jacobs Karin
Published: February 2016

Significance

Contact lines form at phase boundary intersections, quintessentially liquid/vapor interfaces at solid surfaces. Whereas classical hydrodynamic models predict that contact line motion requires infinite energy, common observations of moving droplets show that huge amounts of energy are unnecessary. Slip, wherein a fluid slides along a solid boundary, offers relief of such divergences, and has gained attention with the developing fields of micro- and nanofluidics. This article focuses on contact line motion of retracting liquid droplets with micrometric dimensions. Slip is tuned by changing a nanometric substrate surface layer. The resulting contact line motion and droplet evolutions are hugely influenced by slip, thus offering insights on the question: How do contact lines move?
Sequential activation and distinct functions for distal and proximal modules within the IgH 3′ regulatory region
Authors: Garot Armand , Marquet Marie , Saintamand Alexis , Bender Sébastien , Le Noir Sandrine , Rouaud Pauline , Carrion Claire , Oruc Zéliha , Bébin Anne-Gaëlle , Moreau Jeanne , Lebrigand Kevin , Denizot Yves , Alt Frederick W. , Cogné Michel , Pinaud Eric
Published: February 2016

Significance

The immunoglobulin heavy chain (IgH) 3′regulatory region (3′RR) fine-tunesIgHgene expression during B cell development. One singularity of this region is its quasi-palindromic structure conserved in the3′RRof other species. By comparing previous mouse knockout (KO) models (3′RR-andhs3b-4KO) to a novel mutant devoid of the quasi-palindrome (3′PALKO), we highlighted common features and differences that specify two distinct regulatory entities: (i) the distal module (hs4) is sufficient for normal IgH expression up to the naïve B cell stage; (ii) during B-cell activation, the proximal module (quasi-palindrome) is important for both class switch recombination and somatic hypermutation; and (iii) in plasma cells, the quasi-palindrome is required for robust transcription of the IgH locus.
Assessment of fight outcome is needed to activate socially driven transcriptional changes in the zebrafish brain
Authors: Oliveira Rui F. , Simões José M. , Teles Magda C. , Oliveira Catarina R. , Becker Jorg D. , Lopes João S.
Published: February 2016

Significance

Within social groups, there are animals of different social status that express different behavioral profiles that are paralleled by different patterns of gene expression in the brain. However, social status is not fixed, but rather depends on social interactions; hence, group living animals must be able to switch between different status-dependent behavior and brain gene expression profiles. Here we show for the first time, to our knowledge, that what triggers a genomic response to a social interaction in zebrafish is the subjects’ assessment of the interaction rather than a fixed response to a releaser cue in the environment. The occurrence of fighting assessment in zebrafish suggests that a cognitive ability classically considered complex is also present in a simple-minded vertebrate.
Defining the rate-limiting processes of bacterial cytokinesis
Authors: Coltharp Carla , Buss Jackson , Plumer Trevor M. , Xiao Jie
Published: February 2016

Significance

Bacterial cytokinesis is orchestrated by a macromolecular complex termed the divisome. Central to the divisome is a ring-like, polymeric structure, called the FtsZ-ring (Z-ring). The Z-ring may generate a constrictive force analogous to that provided by the eukaryotic actomyosin ring to drive membrane invagination during cytokinesis. By combining single-molecule imaging with genetic manipulations, we found that, unexpectedly, the rate of septum closure in
Escherichia coli
cells during cytokinesis is robust to many substantial Z-ring perturbations but limited by a specific cell wall synthesis enzyme and further modulated by a physical link between the divisome and chromosome. Our results challenge the long-held Z-ring–centric view of bacterial cytokinesis and support a holistic view of constrictive force generation by the multicomponent divisome.
New type of Weyl semimetal with quadratic double Weyl fermions
Authors: Huang Shin-Ming , Xu Su-Yang , Belopolski Ilya , Lee Chi-Cheng , Chang Guoqing , Chang Tay-Rong , Wang BaoKai , Alidoust Nasser , Bian Guang , Neupane Madhab , Sanchez Daniel , Zheng Hao , Jeng Horng-Tay , Bansil Arun , Neupert Titus , Lin Hsin , Hasan M. Zahid
Published: February 2016

Significance

We predict a new Weyl semimetal candidate. This is critically needed for this rapidly developing field as TaAs is the only known Weyl semimetal in nature. We show that SrSi
2
has many new and novel properties not possible in TaAs. Our prediction provides a new route to studying the elusive Weyl fermion particles originally considered in high-energy physics by tabletop experiments.