bluuebunny/crossref_metadata_2025 huggingface dataset:
AGN-host connection at 0.5 < z < 2.5: A rapid evolution of AGN fraction in red galaxies during the last 10 Gyr
Authors: Wang Tao , Elbaz D. , Alexander D. M. , Xue Y. Q. , Gabor J. M. , Juneau S. , Schreiber C. , Zheng X.-Z. , Wuyts S. , Shi Y. , Daddi E. , Shu X.-W. , Fang G.-W. , Huang J.-S. , Luo B. , Gu Q.-S.
Published: January 2017

We explore the dependence of the incidence of moderate-luminosity (L0.5−8 keV = 1041.9−43.7 erg s-1) active galactic nuclei (AGNs) and the distribution of their accretion rates on host color at 0.5 <z < 2.5. Based on the deepest X-ray and UV-to-far-infrared data in the two The Great Observatories Origins Deep Survey (GOODS) fields, we identify 221 AGNs within a mass-complete parent galaxy sample down to M∗ > 1010 M⊙. We use extinction-corrected rest-frame U−V colors to divide both AGN hosts and non-AGN galaxies into red sequence (red), green valley (green), and blue cloud (blue) populations. We find that the fraction of galaxies hosting an AGN at fixed X-ray luminosity increases with stellar mass and redshift for all the three galaxy populations, independent of their colors. However, both the AGN fraction at fixed stellar mass and its evolution with redshift are clearly dependent on host colors. Most notably, red galaxies have the lowest AGN fraction (~5%) at z ~ 1 yet with most rapid evolution with redshift, increasing by a factor of ~5 (24%) at z ~ 2. Green galaxies exhibit the highest AGN fraction across all redshifts, which is most pronounced at z ~ 2 with more than half of them hosting an AGN at M∗ > 1010.6 M⊙. Together with the high AGN fraction in red galaxies at z ~ 2, this indicates that (X-ray) AGNs could be important in both transforming (quenching) star-forming galaxies into quiescent ones and subsequently maintaining their quiescence at high redshift. Furthermore, consistent with previous studies at lower redshifts, we show that the probability of hosting an AGN for the total galaxy population can be characterized by a universal Eddington ratio (as approximated by LX/M∗) distribution (p(λEdd) ~ λEdd-0.4), which is independent on host mass. Yet consistent with their different AGN fractions, galaxies with different colors appear to also have different p(λEdd) with red galaxies exhibiting more rapid redshift evolution compared with that for green and blue galaxies. Evidence for a steeper power-law distribution of p(λEdd) in red galaxies (p(λEdd) ~ λEdd-0.6) is also presented, though larger samples are needed to confirm. These results suggest that the AGN accretion or the growth of supermassive black holes is related to their host properties, and may also influence their hosts in a different mode dependent on the host color.
Clinical Study of 3D Imaging and 3D Printing Technique for Patient-Specific Instrumentation in Total Knee Arthroplasty
Authors: Liu Fei , Tang Bensen , Deng Biyong , Liu Fang , Zhu Weimin , Zhen Dong , Xue Mingyuan , Zhang Mingjiao , Qiu Bing
Published: January 2017

Patient-specific instrumentation (PSI) was designed to improve the accuracy of preoperative planning and postoperative prosthesis positioning in total knee arthroplasty (TKA). However, better understanding needs to be achieved due to the subtle nature of the PSI systems. In this study, 3D printing technique based on the image data of computed tomography (CT) has been utilized for optimal controlling of the surgical parameters. Two groups of TKA cases have been randomly selected as PSI group and control group with no significant difference of age and sex (p > 0.05). The PSI group is treated with 3D printed cutting guides whereas the control group is treated with conventional instrumentation (CI). By evaluating the proximal osteotomy amount, distal osteotomy amount, valgus angle, external rotation angle, and tibial posterior slope angle of patients, it can be found that the preoperative quantitative assessment and intraoperative changes can be controlled with PSI whereas CI is relied on experience. In terms of postoperative parameters, such as hip-knee-ankle (HKA), frontal femoral component (FFC), frontal tibial component (FTC), and lateral tibial component (LTC) angles, there is a significant improvement in achieving the desired implant position (p < 0.05). Assigned from the morphology of patients' knees, the PSI represents the convergence of congruent designs with current personalized treatment tools. The PSI can achieve less extremity alignment and greater accuracy of prosthesis implantation compared against control method, which indicates potential for optimal HKA, FFC, and FTC angles.
The
Obalon swallowable intragastric balloon in pediatric and adolescent morbid
obesity
Authors: De Peppo Francesco , Caccamo Romina , Adorisio Ottavio , Ceriati Emanuela , Marchetti Paola , Contursi Antonio , Alterio Arianna , Della Corte Claudia , Manco Malnia , Nobili Valerio
Published: January 2017

Background and study aims Incidence of morbid
obesity has grown dramatically in the last half century and this phenomenon
affects with particular severity the pediatric population. Dietary restrictions
and careful programs to improve lifestyle are often ineffective to manage this
particular group of patients, due to poor compliance typical of the adolescence.
The aim of this study was to evaluate the effectiveness of a new intragastric
balloon for treatment of morbidly obese children.

Patients and methods A new swallowable intragastric balloon (Obalon) has
been used for the first time in 17 obese children in order to assess its safety
and effectiveness in terms of reduction in excess weight. In 9 of 17 children a
second balloon was placed 30 to 40 days after the first insertion. All devices
were endoscopically removed after a mean time of 18 weeks.

Results In the group of 16 patients who completed the study (1 patient
still under treatment) mean weight decreased from 95.8 ± 18.4 Kg to 83.6 ± 27.1
(P < 0.05). Mean body mass index (BMI) decreased from 35.27± 5.89
(range 30.4 – 48) to 32.25 ± 7.1 (range 23.5 – 45.7) (P > 0.05); mean
excess weight, calculated according to Cole’s curves for pediatric populations,
decreased from 36.2 ± 15.9 to 29.4 ± 18.3 Kg (P = 0.14), with an %EWL of
20.1 ± 9.8 (range 2.3 – 35.1). Waist circumference decreased from 109 ± 12.3 cm
to 99 ± 10.5 cm (P < 0.05).

Conclusions Obalon can be administered easily without complications,
inducing an appreciable weight loss with a statistically significant reduction
in BMI and an improvement in associated
comorbidities.
Study of plasma pressure evolution driven by strong picosecond laser pulse
Authors: Li M. , Wang J. X. , Xu Y. X. , Zhu W. J.
Published: January 2017

Through one dimensional relativistic particle-in-cell simulation of strong laser interaction with the solid-density plasma, the evolution of the plasma impact pressure behind a thin foil has been investigated in details. An energy-compression mechanism has been proposed to help optimizing the laser and plasma parameters. It has been found that by using a picosecond laser with intensity 1015 W cm–2, an impact pressure as high as several hundreds of GPa order of magnitude can be obtained. The numerical analysis demonstrates that the peak pressure is mainly resulted from the ion contribution. These results are of potential application to the laser loading upon solids in order to study the material properties under extra-high dynamic pressure.
Langevin-Poisson-EQT: A dipolar solvent based quasi-continuum approach for electric double layers
Authors: Mashayak S. Y. , Aluru N. R.
Published: January 2017

Water is a highly polar solvent. As a result, electrostatic interactions of interfacial water molecules play a dominant role in determining the distribution of ions in electric double layers (EDLs). Near a surface, an inhomogeneous and anisotropic arrangement of water molecules gives rise to pronounced variations in the electrostatic and hydration energies of ions. Therefore, a detailed description of the structural and dielectric properties of water is important to study EDLs. However, most theoretical models ignore the molecular effects of water and treat water as a background continuum with a uniform dielectric permittivity. Explicit consideration of water polarization and hydration of ions is both theoretically and numerically challenging. In this work, we present an empirical potential-based quasi-continuum theory (EQT) for EDL, which incorporates the polarization and hydration effects of water explicitly. In EQT, water molecules are modeled as Langevin point dipoles and a point dipole based coarse-grained model for water is developed systematically. The space dependence of the dielectric permittivity of water is included in the Poisson equation to compute the electrostatic potential. In addition, to reproduce hydration of ions, ion-water coarse-grained potentials are developed. We demonstrate the EQT framework for EDL by simulating NaCl aqueous electrolyte confined inside slit-like capacitor channels at various ion concentrations and surface charge densities. We show that the ion and water density predictions from EQT agree well with the reference molecular dynamics simulations.
Spreading and breakup of nanodroplet impinging on surface
Authors: Li Bu-Xuan , Li Xin-Hao , Chen Min
Published: January 2017

The normal impinging of nanoscale water droplets on the solid surface is investigated through molecular dynamics simulations. A wide regime of impinging from spreading to breakup is studied. The overestimations of dissipation and surface free energy in literature are modified with a more accurate assumption on flow fields. The refined model fits well with the simulation results by introducing the linear distribution of radial velocity gradient. Two modes of breakup are observed during the nanodroplet impinging on the surface: (1) touch-bottom of the surface of the liquid film and (2) propagation of finger-like projections on the flow frontier. The touch-bottom breakup is possibly the dominant mode in cases with large We and small Re. The criterion is proposed to be that the amplitude of the capillary wave is larger than the average height of the droplets at the maximum spreading state. This criterion gives a well prediction comparing to the results obtained in molecular dynamics simulations.
Characterization of the interface of binary mixed DOPC:DOPS liposomes in water: The impact of charge condensation
Authors: Lütgebaucks Cornelis , Macias-Romero Carlos , Roke Sylvie
Published: January 2017

Solutions of liposomes composed of binary mixtures of anionic dioleoylphosphatidylserine (DOPS) and zwitterionic dioleoylphosphatidylcholine (DOPC) are investigated with label-free angle-resolved (AR) second harmonic scattering (SHS) and electrophoretic mobility measurements. The membrane surface potential is extracted from the AR-SHS response. The surface potential changes from −10 to −145 mV with varying DOPS content ( from 0% to 100%) and levels off already at ∼ 10 % DOPS content. The ζ-potential shows the same trend but with a drastically lower saturation value (−44 mV). This difference is explained by the formation of a condensed layer of Na+ counterions around the outer leaflet of the liposome as predicted by charge condensation theories for polyelectrolyte systems.
Investigation of instabilities and rotation alteration in high beta KSTAR plasmas
Authors: Park Y. S. , Sabbagh S. A. , Ko W. H. , Bak J. G. , Berkery J. W. , Bialek J. M. , Choi M. J. , Hahn S. H. , In Y. K. , Jardin S. C. , Jeon Y. M. , Kim J. , Kwak J. G. , Lee S. G. , Oh Y. K. , Park H. K. , Yoon S. W. , Yun G. S.
Published: January 2017

H-mode plasma operation of the Korea Superconducting Tokamak Advanced Research (KSTAR) device has been expanded to significantly surpass the ideal MHD no-wall beta limit. Plasmas with high normalized beta, βN, up to 4.3 have been achieved with reduced plasma internal inductance, li, to near 0.7, exceeding the computed n = 1 ideal no-wall limit by a factor of 1.6. Pulse lengths at maximum βN were extended to longer pulses by new, more rapid control. The stability of the observed m/n = 2/1 tearing mode that limited the achieved high βN is computed by the M3D-C1 code, and the effect of sheared toroidal rotation to tearing stability is examined. As a method to affect the mode stability in high βN plasmas, the non-resonant alteration of the rotation profile by non-axisymmetric magnetic fields has been used, enabling a study of the underlying neoclassical toroidal viscosity (NTV) physics and stability dependence on rotation. Non-axisymmetric field spectra were applied using in-vessel control coils (IVCCs) with varied n = 2 field configurations to alter the plasma toroidal rotation profile in high beta H-mode plasmas and to analyze their effects on the rotation. The rotation profile was significantly altered with rotation reduced by more than 60% without tearing activity or mode locking. To investigate the physical characteristics and scaling of the measured rotation braking by NTV, changes in the rotation profile are analytically examined in steady state. The expected NTV scaling with the square of the normalized applied field perturbation agrees with the measured profile change δB2.1–2.3. The NTV is also found to scale as Ti2.1–2.4, in general agreement with the low collisionality “1/ν” regime scaling of the NTV theory (TNTV-(1/ν) ∝ Ti2.5).
Identification of simple reaction coordinates from complex dynamics
Authors: McGibbon Robert T. , Husic Brooke E. , Pande Vijay S.
Published: January 2017

Reaction coordinates are widely used throughout chemical physics to model and understand complex chemical transformations. We introduce a definition of the natural reaction coordinate, suitable for condensed phase and biomolecular systems, as a maximally predictive one-dimensional projection. We then show that this criterion is uniquely satisfied by a dominant eigenfunction of an integral operator associated with the ensemble dynamics. We present a new sparse estimator for these eigenfunctions which can search through a large candidate pool of structural order parameters and build simple, interpretable approximations that employ only a small number of these order parameters. Example applications with a small molecule’s rotational dynamics and simulations of protein conformational change and folding show that this approach can filter through statistical noise to identify simple reaction coordinates from complex dynamics.
A non-empirical gas slippage model for low to moderate Knudsen numbers
Authors: Wang Shihao , Lukyanov Alexander A. , Wang Lei , Wu Yu-Shu , Pomerantz Andrew , Xu Wenyue , Kleinberg Robert
Published: January 2017

In this study, we present a novel derivation of the gas slip flow boundary condition within micro- and nano-flow channels. The newly derived boundary condition is of second order. Our model is based on the kinetic theory of gases. The slippage condition is obtained via the calculation of the shear stress in a confined micro-channel. We have benchmarked the mass transfer rate predicted by our model with existing numerical and physical experimental data, and the new model matches experiments within 10%.
Multi-layer thick gas electron multiplier (M-THGEM): A new MPGD structure for high-gain operation at low-pressure
Authors: Cortesi M. , Rost S. , Mittig W. , Ayyad-Limonge Y. , Bazin D. , Yurkon J. , Stolz A.
Published: January 2017

The operating principle and performances of the Multi-layer Thick Gaseous Electron Multiplier (M-THGEM) are presented. The M-THGEM is a novel hole-type gaseous electron multiplier produced by multi-layer printed circuit board technology; it consists of a densely perforated assembly of multiple insulating substrate sheets (e.g., FR-4), sandwiched between thin metallic-electrode layers. The electron avalanche processes occur along the successive multiplication stages within the M-THGEM holes, under the action of strong dipole fields resulting from the application of suitable potential differences between the electrodes. The present work focuses on the investigation of two different geometries: a two-layer M-THGEM (either as single or double-cascade detector) and a single three-layer M-THGEM element, tested in various low-pressure He-based gas mixtures. The intrinsically robust confinement of the avalanche volume within the M-THGEM holes provides an efficient reduction of the photon-induced secondary effects, resulting in a high-gain operation over a broad pressure range, even in pure elemental gas. The operational principle, main properties (maximum achievable gain, long-term stability, energy resolution, etc.) under different irradiation conditions, as well as capabilities and potential applications are presented and discussed.
A free energy study of carbon clusters on Ir(111): Precursors to graphene growth
Authors: Tetlow H. , Ford I. J. , Kantorovich L.
Published: January 2017

It is widely accepted that the nucleation of graphene on transition metals is related to the formation of carbon clusters of various sizes and shapes on the surface. Assuming a low concentration of carbon atoms on a crystal surface, we derive a thermodynamic expression for the grand potential of the cluster of N carbon atoms, relative to a single carbon atom on the surface (the cluster work of formation). This is derived taking into account both the energetic and entropic contributions, including structural and rotational components, and is explicitly dependent on the temperature. Then, using ab initio density functional theory, we calculate the work of formation of carbon clusters CN on the Ir(111) surface as a function of temperature considering clusters with up to N = 16 C atoms. We consider five types of clusters (chains, rings, arches, top-hollow, and domes), and find, in agreement with previous zero temperature studies, that at elevated temperatures the structure most favoured depends on N, with chains and arches being the most likely at N<10 and the hexagonal domes becoming the most favourable at all temperatures for N>10. Our calculations reveal the work of formation to have a much more complex character as a function of the cluster size than one would expect from classical nucleation theory: for typical conditions, the work of formation displays not one but two nucleation barriers, at around N = 4–5 and N = 9–11. This suggests, in agreement with existing LEEM data, that five atom carbon clusters, along with C monomers, must play a pivotal role in the nucleation and growth of graphene sheets, whereby the formation of large clusters is achieved from the coalescence of smaller clusters (Smoluchowski ripening). Although the main emphasis of our study is on thermodynamic aspects of nucleation, the pivotal role of kinetics of transitions between different cluster types during the nucleation process is also discussed for a few cases as illustrative examples.
Structures and electronic properties of B3Sin− (n = 4–10) clusters: A combined ab initio and experimental study
Authors: Wu Xue , Lu Sheng-Jie , Liang Xiaoqing , Huang Xiaoming , Qin Ying , Chen Maodu , Zhao Jijun , Xu Hong-Guang , King R. Bruce , Zheng Weijun
Published: January 2017

The anionic silicon clusters doped with three boron atoms, B3Sin− (n = 4–10), have been generated by laser vaporization and investigated by anion photoelectron spectroscopy. The vertical detachment energies (VDEs) and adiabatic detachment energies (ADEs) of these anionic clusters are determined. The lowest energy structures of B3Sin− (n = 4–10) clusters are globally searched using genetic algorithm incorporated with density functional theory (DFT) calculations. The photoelectron spectra, VDEs, ADEs of these B3Sin− clusters (n = 4–10) are simulated using B3LYP/6-311+G(d) calculations. Satisfactory agreement is found between theory and experiment. Most of the lowest-energy structures of B3Sin− (n = 4–10) clusters can be derived by using the squashed pentagonal bipyramid structure of B3Si4− as the major building unit. Analyses of natural charge populations show that the boron atoms always possess negative charges, and that the electrons transfer from the 3s orbital of silicon and the 2s orbital of boron to the 2p orbital of boron. The calculated average binding energies, second-order differences of energies, and the HOMO-LUMO gaps show that B3Si6− and B3Si9− clusters have relatively high stability and enhanced chemical inertness. In particular, the B3Si9− cluster with high symmetry (C3v) stands out as an interesting superatom cluster with a magic number of 40 skeletal electrons and a closed-shell electronic configuration of 1S21P61D102S22P61F14 for superatom orbitals.
Electronic spectrum and photodissociation chemistry of the linear methyl propargyl cation H2C4H3+
Authors: Catani Katherine J. , Muller Giel , da Silva Gabriel , Bieske Evan J.
Published: January 2017

The electronic spectrum of the methyl propargyl cation (2-butyn-1-yl cation, H2C4H3+) is measured over the 230–270 nm range by photodissociating the bare cation and its Ar and N2 tagged complexes in a tandem mass spectrometer. The observed A′1←A′1 band system has an origin at 37 753 cm−1 for H2C4H3+, 37738 cm−1 for H2C4H3+—Ar, and 37 658 cm−1 for H2C4H3+—N2. The methyl propargyl cation photodissociates to produce either C2H3++C2H2 (protonated acetylene + acetylene) or H2C4H++H2 (protonated diacetylene + dihydrogen). Photodissociation spectra of H2C4H3+, H2C4H3+—Ar, and H2C4H3+—N2 exhibit similar vibronic structure, with a strong progression of spacing 630 cm−1 corresponding to excitation of the C—C stretch mode. Interpretation of the spectra is aided by ground and excited state calculations using time dependent density functional theory at the ωB97X-D/aug-cc-pVDZ level of theory. Ab initio calculations and master equation simulations were used to interpret the dissociation of H2C4H3+ on the ground state manifold. These calculations support the experimentally observed product branching ratios in which acetylene elimination dominates and also suggests that channel switching occurs at higher energies to favor H2 elimination.
Center conductor diagnostic for multipactor detection in inaccessible geometries
Authors: Chaplin Vernon H. , Hubble Aimee A. , Clements Kathryn A. , Graves Timothy P.
Published: January 2017

Electron collecting current probes are the most reliable diagnostic of multipactor and radiofrequency (RF) ionization breakdown; however, stand-alone probes can only be used in test setups where the breakdown region is physically accessible. This paper describes techniques for measuring multipactor current directly on the center conductor of a coaxial RF device (or more generally, on the signal line in any two-conductor RF system) enabling global multipactor detection with improved sensitivity compared to other common diagnostics such as phase null, third harmonic, and reflected power. The center conductor diagnostic may be AC coupled for use in systems with a low DC impedance between the center conductor and ground. The effect of DC bias on the breakdown threshold was studied: in coaxial geometry, the change in threshold was <1 dB for positive biases satisfying VDC/VRF0<0.8, where VRF0 is the RF voltage amplitude at the unperturbed breakdown threshold. In parallel plate geometry, setting VDC/VRF0<0.2 was necessary to avoid altering the threshold by more than 1 dB. In most cases, the center conductor diagnostic functions effectively with no bias at all—this is the preferred implementation, but biases in the range VDC=0−10V may be applied if necessary. The polarity of the detected current signal may be positive or negative depending on whether there is net electron collection or emission globally.
Structural refinement of Pbnm-type perovskite films from analysis of half-order diffraction peaks
Authors: Brahlek M. , Choquette A. K. , Smith C. R. , Engel-Herbert R. , May S. J.
Published: January 2017

Engineering structural modifications of epitaxial perovskite thin films is an effective route to induce new functionalities or enhance existing properties due to the close relation of the electronic ground state to the local bonding environment. As such, there is a necessity to systematically refine and precisely quantify these structural displacements, particularly those of the oxygen octahedra, which is a challenge due to the weak scattering factor of oxygen and the small diffraction volume of thin films. Here, we present an optimized algorithm to refine the octahedral rotation angles using specific unit-cell-doubling half-order diffraction peaks for the a−a−c+ Pbnm structure. The oxygen and A-site positions can be obtained by minimizing the squared-error between calculated and experimentally determined peak intensities using the (1/2 1/2 3/2) and (1/2 1/2 5/2) reflections to determine the rotation angle α about in-plane axes and the (1/2 5/2 1), (1/2 3/2 1), and (1/2 3/2 2) reflections to determine the rotation angle γ about the out-of-plane axis, whereas the convoluting A-site displacements associated with the octahedral rotation pattern can be determined using (1 1 1/2) and (1/2 1/2 1/2) reflections to independently determine A-site positions. The validity of the approach is confirmed by applying the refinement procedure to determine the A-site and oxygen displacements in a NdGaO3 single crystal. The ability to refine both the oxygen and A-site displacements relative to the undistorted perovskite structure enables a deeper understanding of how structural modifications alter functionality properties in epitaxial films exhibiting this commonly occurring crystal structure.
Spatial luminescence imaging of dopant incorporation in CdTe Films
Authors: Guthrey Harvey , Moseley John , Colegrove Eric , Burst James , Albin David , Metzger Wyatt K. , Al-Jassim Mowafak
Published: January 2017

State-of-the-art cathodoluminescence (CL) spectrum imaging with spectrum-per-pixel CL emission mapping is applied to spatially profile how dopant elements are incorporated into Cadmium telluride (CdTe). Emission spectra and intensity monitor the spatial distribution of additional charge carriers through characteristic variations in the CL emission based on computational modeling. Our results show that grain boundaries play a role in incorporating dopants in CdTe exposed to copper, phosphorus, and intrinsic point defects in CdTe. The image analysis provides critical, unique feedback to understand dopant incorporation and activation in the inhomogeneous CdTe material, which has struggled to reach high levels of hole density.
Ultra-wideband cross polarization conversion metasurface insensitive to incidence angle
Authors: Khan Muhammad Ismail , Fraz Qaisar , Tahir Farooq A.
Published: January 2017

A broadband microwave cross-polarization-conversion (CPC) metasurface is designed, simulated, fabricated, and tested. The metasurface consists of coupled split-ring-resonators (SRRs) with two splits in each SRR and is designed on an FR4 dielectric substrate backed by a metallic ground plane. An efficient CPC, both for normal as well as for oblique incidence, is achieved with 3 dB fractional bandwidth of 73% from 5 to 10.8 GHz. This wideband polarization conversion results from multiple plasmonic resonances occurring at three neighboring frequencies. Owing to the sub-wavelength unit cell size and symmetric structure of the coupled SRRs, the response of the metasurface is independent of the polarization and incidence angle of the incoming wave, which makes it a potential candidate for many practical applications. The proposed design is validated both numerically and experimentally. Experimental results are found to be in good agreement with simulations.
Two-dimensional dissipative rogue waves due to time-delayed feedback in cavity nonlinear optics
Authors: Tlidi Mustapha , Panajotov Krassimir
Published: January 2017

We demonstrate a way to generate two-dimensional rogue waves in two types of broad area nonlinear optical systems subject to time-delayed feedback: in the generic Lugiato-Lefever model and in the model of a broad-area surface-emitting laser with saturable absorber. The delayed feedback is found to induce a spontaneous formation of rogue waves. In the absence of delayed feedback, spatial pulses are stationary. The rogue waves are exited and controlled by the delay feedback. We characterize their formation by computing the probability distribution of the pulse height. The long-tailed statistical contribution, which is often considered as a signature of the presence of rogue waves, appears for sufficiently strong feedback. The generality of our analysis suggests that the feedback induced instability leading to the spontaneous formation of two-dimensional rogue waves is a universal phenomenon.
Self-sustained focusing of high-density streaming plasma
Authors: Bugaev A. , Dobrovolskiy A. , Goncharov A. , Gushenets V. , Litovko I. , Naiko I. , Oks E.
Published: January 2017

We describe our observations of the transport through an electrostatic plasma lens of a wide-aperture, high-current, low energy, metal-ion plasma flow produced by a cathodic arc discharge. The lens input aperture was 80 mm, the length of the lens was 140 mm, and there were three electrostatic ring electrodes located in a magnetic field formed by permanent magnets. The lens outer electrodes were grounded and the central electrode was biased up to −3 kV. The plasma was a copper plasma with directed (streaming) ion energy 20–40 eV, and the equivalent ion current was up to several amperes depending on the potential applied to the central lens electrode. We find that when the central lens electrode is electrically floating, the current density of the plasma flow at the lens focus increases by up to 40%–50%, a result that is in good agreement with a theoretical treatment based on plasma-optical principles of magnetic insulation of electrons and equipotentialization along magnetic field lines. When the central lens electrode is biased negatively, an on-axis stream of energetic electrons is formed, which can also provide a mechanism for focusing of the plasma flow. Optical emission spectra under these conditions show an increase in intensity of lines corresponding to both copper atoms and singly charged copper ions, indicating the presence of fast electrons within the lens volume. These energetic electrons, as well as accumulating on-axis and providing ion focusing, can also assist in reducing the microdroplet component in the dense, low-temperature, metal plasma.
Photoconductivity of InN grown by MOVPE: Low temperature and weak light illumination
Authors: Kang Ting-Ting , Zhang Yuhui , Chen Ping-Ping , Wang ZhiHai , Yamamoto Akio
Published: January 2017

Using a light-emitting diode instead of a laser, we study the photoconductivity (PC) in the metalorganic vapor phase epitaxy grown InN films under 2.3 K–280 K temperature with blocked 300 K blackbody radiation. Although InN's negative PC was observed, it shows a quick response, not a “persistent” one as previously described by PC measurements using laser. An artificial “persistent negative PC” has been experimentally demonstrated by the light heating effect (LHE). The quick response negative PC is weakened by increased temperature and is less dependent on the light intensity. Further analyses show that the so-called “persistent photoconductivity” in InN might be justified as LHE.
Spatiotemporal infrared measurement of interface temperatures during water droplet evaporation on a nonwetting substrate
Authors: Chandramohan Aditya , Weibel Justin A. , Garimella Suresh V.
Published: January 2017

High-fidelity experimental characterization of sessile droplet evaporation is required to understand the interdependent physical mechanisms that drive the evaporation. In particular, cooling of the interface due to release of the latent heat of evaporation, which is not accounted for in simplified vapor-diffusion-based models of droplet evaporation, may significantly suppress the evaporation rate on nonwetting substrates, which support tall droplet shapes. This suppression is counteracted by convective mass transfer from the droplet to the air. While prior numerical modeling studies have identified the importance of these mechanisms, there is no direct experimental evidence of their influence on the interfacial temperature distribution. Infrared thermography is used here to simultaneously measure the droplet volume, contact angle, and spatially resolved interface temperatures for water droplets on a nonwetting substrate. The technique is calibrated and validated to quantify the temperature measurement accuracy; a correction is employed to account for reflections from the surroundings when imaging the evaporating droplets. Spatiotemporally resolved interface temperature data, obtained via infrared thermography measurements, allow for an improved prediction of the evaporation rate and can be utilized to monitor temperature-controlled processes in droplets for various lab-on-a-chip applications.
Less-invasive non-embedded cell cutting by nanomanipulation and vibrating nanoknife
Authors: Shang Wanfeng , Li Dengfeng , Lu Haojian , Fukuda Toshio , Shen Yajing
Published: January 2017

The less-invasive non-embedded cell cutting or slicing technique provides opportunities for a bio-study at subcellular scale, but there are few effective solutions available at the current stage. This paper reports a robot-aided vibrating system for less-invasive non-embedded cell cutting and investigates the role of key vibrating parameters in the cell cutting process. First, a nanoknife with sharp angle 5° is fabricated from a commercial atomic force microscope cantilever by focused ion beam etching and a vibrating system is constructed from a piezo actuator. Then, they are integrated with a self-developed nanorobotic manipulation system inside an environment scanning electron microscope. After that, we choose yeast cells as the sample to implement the vibrating cutting and investigate the effect of vibrating parameters (frequency and amplitude) on cell cutting quality. The results clearly indicate that the vibrating nanoknife is able to reduce the cutting force and improve the cutting quality. It is also suggested that the repeated load-unload (impact) cycle is the main reason for the better performance of vibrating cutting. The effect of vibrating parameters at small scale benefits our fundamental understanding on cell mechanics, and this research paves a way for the low-destructive non-embedded cell cutting and promotes the practical cell cutting techniques.
Separation of the surface and bulk recombination in silicon by means of transient photoluminescence
Authors: Heinz Friedemann D. , Warta Wilhelm , Schubert Martin C.
Published: January 2017

The bulk and surface recombination determine the electrical performance of many semiconductor devices. Yet, the experimental determination and separation of both surface and bulk recombination rate remains challenging. This paper presents the measurement and separation of the bulk and surface recombination in silicon by means of time resolved photoluminescence spectroscopy. The high temporal resolution of the applied time correlated single photon counting technique is exploited to access the photoluminescence response of a silicon sample upon pulsed excitation in the nanosecond to millisecond regime on a sub-cm2 area. A rigorous data fitting algorithm based on two dimensional numeric simulations of the induced charge carrier dynamics is applied to extract all information on bulk and surface recombination properties from the recorded photoluminescence transients. Using different samples with symmetric as well as asymmetric surface recombination properties, we demonstrate the capabilities of the proposed contactless and nondestructive technique, which may be applicable to silicon based mono- or multi-junction devices.
Nanoantenna-induced current enhancement of nano-sized metal/oxide interfaces
Authors: Hou Jiechang , Zhu Hai , Reed Jason C. , Yi Fei , Cubukcu Ertugrul , Bonnell Dawn A.
Published: January 2017

Nanoantenna resonance is demonstrated on nano-sized gold/SrTiO3 interfaces. This resonance arising from the collective oscillation of free electrons results in photocurrent current enhancement, facilitated by the built-in electric field at the Schottky interface. This current enhancement around the nanoantenna resonance peak can be attributed to hot electron generation and extraction. The photocurrent dependence on incident wavelength and power was characterized. Applying external bias, improved the current enhancement by orders of magnitude.
Are regional and remote Western Australian children eating for good health? An investigation into fruit and vegetable consumption
Authors: Godrich Stephanie L. , Lo Johnny , Davies Christina R. , Darby Jill , Devine Amanda
Published: January 2017

Issue addressed

Little is known about the fruit and vegetable (F&V) habits of regional and remote Western Australian (WA) children beyond quantities consumed. This study aimed to ascertain the proportion of regional and remote WA children who met the Australian Dietary Guidelines (ADG) for F&V; the types and varieties of F&V consumed; and whether consumption behaviour was associated with remoteness.

Methods

Caregiver and child dyads (n = 256 dyads) completed similar paper‐based surveys, 196 of these children completed 24‐h dietary records. Statistical analyses were conducted using IBM SPSS (version 23).

Results

Overall, children were less likely to adhere to vegetables (15.4%) than fruit (65.8%) guidelines. Adherence to the ADG did not significantly differ between regional and remote locations. However, a higher proportion of remote children consumed dried fruit compared with regional children, while significantly more regional children compared with remote children consumed from the ‘pome, tropical and stone fruit’ group and the ‘starchy vegetables’, ‘red/orange vegetables’ and ‘dark green leafy vegetables’ groups.

Conclusions

Many regional and remote WA children consumed F&V in suboptimal amounts. Further research should aim to ascertain factors that increase or decrease the likelihood of ADG adherence across regional and remote WA and determine why certain F&V variety groups and types differed in consumption across Remoteness Areas.

So what

This study provided closer scrutiny of WA children's F&V consumption habits, highlighting the differences in consumption behaviours due to remoteness and identifying specific areas that require further investigation.
Interference of the complex between NCS-1 and Ric8a with phenothiazines regulates synaptic function and is an approach for fragile X syndrome
Authors: Mansilla Alicia , Chaves-Sanjuan Antonio , Campillo Nuria E. , Semelidou Ourania , Martínez-González Loreto , Infantes Lourdes , González-Rubio Juana María , Gil Carmen , Conde Santiago , Skoulakis Efthimios M. C. , Ferrús Alberto , Martínez Ana , Sánchez-Barrena María José
Published: January 2017

Significance

Neurons coregulate their number of synapses and the probability of neurotransmitter release per synapse in an antagonistic manner. The binding of neuronal calcium sensor 1 (NCS-1) to the guanine exchange factor protein Ric8a coregulates these neuronal features. This study identified a small molecule, the phenothiazine FD44, that binds the interaction surface between NCS-1 and Ric8a, preventing the formation of the complex. Tested on a
Drosophila
model of the fragile X syndrome, where the number of synapses is in excess, FD44 proves effective to reduce synapse number to normal levels and restore normal learning performance. Our structure–function study shows the specificity of this compound and the drugability of the NCS-1/Ric8a interface for the treatment of fragile X and possibly, other synaptopathies.
Synchronized chaotic targeting and acceleration of surface chemistry in prebiotic hydrothermal microenvironments
Authors: Priye Aashish , Yu Yuncheng , Hassan Yassin A. , Ugaz Victor M.
Published: January 2017

Significance

We describe a physical mechanism capable of achieving simultaneous mixing and focused enrichment in hydrothermal pore microenvironments. Microscale chaotic advection established in response to a temperature gradient paradoxically promotes bulk homogenization of molecular species, while at the same time transporting species to discrete targeted locations on the bounding sidewalls where they become highly enriched. This process delivers an order of magnitude acceleration in surface reaction kinetics under conditions naturally found in subsea hydrothermal microenvironments, suggesting a new avenue to explain prebiotic emergence of macromolecules from dilute organic precursors—a key unanswered question in the origin of life on Earth and elsewhere.
Mycobacterial ESX-1 secretion system mediates host cell lysis through bacterium contact-dependent gross membrane disruptions
Authors: Conrad William H. , Osman Morwan M. , Shanahan Jonathan K. , Chu Frances , Takaki Kevin K. , Cameron James , Hopkinson-Woolley Digby , Brosch Roland , Ramakrishnan Lalita
Published: January 2017

Significance

Secreted pore-forming toxins are a common feature of bacterial virulence.Mycobacterium tuberculosis, the agent of human tuberculosis, has been reported to possess a pore-forming toxin called 6 kDa early secretory antigenic target (ESAT-6) that is secreted through a specialized secretion system called ESX-1 (ESAT-6 secretion system 1). We report here experiments showing that ESAT-6 does not lyse cells; the lytic activity previously attributed to this secreted protein is due to contaminating detergent in the recombinant protein preparations. Whereas the ESX-1 secretion system does lyse host cell membranes, we find this lysis is dependent on bacterial cell contact with the host membrane and results in tears in the membrane without any pore formation. Understanding the mechanism of this lysis may provide clues to how mycobacteria cause disease.
Pet Project or Best Project? Online Decision Support Tools for Prioritizing Barrier Removals in the Great Lakes and Beyond
Authors: Moody Allison T. , Neeson Thomas M. , Wangen Steve , Dischler Jeff , Diebel Matthew W. , Milt Austin , Herbert Matthew , Khoury Mary , Yacobson Eugene , Doran Patrick J. , Ferris Michael C. , O'Hanley Jesse R. , McIntyre Peter B.
Published: January 2017

Structures that block movement of fish through river networks are built to serve a variety of societal needs, including transportation, hydroelectric power, and exclusion of exotic species. Due to their abundance, road crossings and dams reduce the amount of habitat available to fish that migrate from the sea or lakes into rivers to breed. The benefits to fish of removing any particular barrier depends on its location within the river network, its passability to fish, and the relative position of other barriers within the network. Balancing the trade-offs between ecological and societal values makes choosing among potential removal projects difficult. To facilitate prioritization of barrier removals, we developed an online decision support tool (DST) with three functions: (1) view existing barriers at various spatial scales; (2) modify information about barriers, including removal costs; and (3) run optimization models to identify portfolios of removals that provide the greatest amount of habitat access for a given budget. A survey of available DSTs addressing barrier removal prioritization indicates that barrier visualization is becoming widespread but few tools allow dynamic calculation of connectivity metrics, scenario analysis, or optimization. Having these additional functions, our DST enables organizations to develop barrier removal priorities based on cost-effectiveness in restoring aquatic connectivity.
Argumentative skills development in teaching philosophy to secondary school students through constructive controversy: an exploratory study case
Authors: Morais Teresa , Silva Helena , Lopes José , Dominguez Caroline
Published: January 2017

The use of argumentative strategies that promote the defense of well‐grounded personal arguments contributes to the development of a critical, ethical and political thought that leads to responsible and socially committed people. Based on the quality of the produced arguments in philosophical essays, this work evaluates the potential application of a cooperative learning method – the constructive controversy – for the development of argumentative skills in secondary school students in philosophy. The quality of the arguments was evaluated through the analysis of a total of 144 philosophical essays produced by the students over a school year. The results point to the advantages of using this method over more traditional ones in the acquisition of argumentative skills.
The Vps13p–Cdc31p complex is directly required for TGN late endosome transport and TGN homotypic fusion
Authors: De Mithu , Oleskie Austin N. , Ayyash Mariam , Dutta Somnath , Mancour Liliya , Abazeed Mohamed E. , Brace Eddy J. , Skiniotis Georgios , Fuller Robert S.
Published: January 2017

Yeast VPS13 is the founding member of a eukaryotic gene family of growing interest in cell biology and medicine. Mutations in three of four human VPS13 genes cause autosomal recessive neurodegenerative or neurodevelopmental disease, making yeast Vps13p an important structural and functional model. Using cell-free reconstitution with purified Vps13p, we show that Vps13p is directly required both for transport from the trans-Golgi network (TGN) to the late endosome/prevacuolar compartment (PVC) and for TGN homotypic fusion. Vps13p must be in complex with the small calcium-binding protein Cdc31p to be active. Single-particle electron microscopic analysis of negatively stained Vps13p indicates that this 358-kD protein is folded into a compact rod-shaped density (20 × 4 nm) with a loop structure at one end with a circular opening ∼6 nm in diameter. Vps13p exhibits ATP-stimulated binding to yeast membranes and specific interactions with phosphatidic acid and phosphorylated forms of phosphatidyl inositol at least in part through the binding affinities of conserved N- and C-terminal domains.
The intrinsically liganded cyclic nucleotide–binding homology domain promotes KCNH channel activation
Authors: Zhao Yaxian , Goldschen-Ohm Marcel P. , Morais-Cabral João H. , Chanda Baron , Robertson Gail A.
Published: January 2017

Channels in the ether-à-go-go or KCNH family of potassium channels are characterized by a conserved, C-terminal domain with homology to cyclic nucleotide–binding homology domains (CNBhDs). Instead of cyclic nucleotides, two amino acid residues, Y699 and L701, occupy the binding pocket, forming an “intrinsic ligand.” The role of the CNBhD in KCNH channel gating is still unclear, however, and a detailed characterization of the intrinsic ligand is lacking. In this study, we show that mutating both Y699 and L701 to alanine, serine, aspartate, or glycine impairs human EAG1 channel function. These mutants slow channel activation and shift the conductance–voltage (G–V) relation to more depolarized potentials. The mutations affect activation and the G-V relation progressively, indicating that the gating machinery is sensitive to multiple conformations of the CNBhD. Substitution with glycine at both sites (GG), which eliminates the side chains that interact with the binding pocket, also reduces the ability of voltage prepulses to populate more preactivated states along the activation pathway (i.e., the Cole–Moore effect), as if stabilizing the voltage sensor in deep resting states. Notably, deletion of the entire CNBhD (577–708, ΔCNBhD) phenocopies the GG mutant, suggesting that GG is a loss-of-function mutation and the CNBhD requires an intrinsic ligand to exert its functional effects. We developed a kinetic model for both wild-type and ΔCNBhD mutant channels that describes all our observations on activation kinetics, the Cole–Moore shift, and G-V relations. These findings support a model in which the CNBhD both promotes voltage sensor activation and stabilizes the open pore. The intrinsic ligand is critical for these functional effects.
A missense mutation makes a mess of Ca2+ sensing
Authors: Sedwick Caitlin
Published: January 2017

A new JGP study shows how a disease-causing mutation in RyR2 dramatically alters channel behavior.