bluuebunny/crossref_metadata_2025 huggingface dataset:
A non-scale-invariant form for coarse-grained diffusion-reaction equations
Authors: Ostvar Sassan , Wood Brian D.
Published: September 2016

The process of mixing and reaction is a challenging problem to understand mathematically. Although there have been successes in describing the effective properties of mixing and reaction under a number of regimes, process descriptions for early times have been challenging for cases where the structure of the initial conditions is highly segregated. In this paper, we use the method of volume averaging to develop a rigorous theory for diffusive mixing with reactions from initial to asymptotic times under highly segregated initial conditions in a bounded domain. One key feature that arises in this development is that the functional form of the averaged differential mass balance equations is not, in general, scale invariant. Upon upscaling, an additional source term arises that helps to account for the initial configuration of the reacting chemical species. In this development, we derive the macroscopic parameters (a macroscale source term and an effectiveness factor modifying the reaction rate) defined in the macroscale diffusion-reaction equation and provide example applications for several initial configurations.
High dopant activation of phosphorus in Ge crystal with high-temperature implantation and two-step microwave annealing
Authors: Shih Tzu-Lang , Su Yin-Hsien , Lee Wen-Hsi
Published: September 2016

In this letter, high-temperature ion implantation and low-temperature microwave annealing were employed to achieve high n-type active concentrations, approaching the solid solubility limit, in germanium. To use the characteristics of microwave annealing more effectively, a two-step microwave annealing process was employed. In the first annealing step, a high-power (1200 W; 425 °C) microwave was used to achieve solid-state epitaxial regrowth and to enhance microwave absorption. In the second annealing step, contrary to the usual process of thermal annealing with higher temperature, a lower-power (900 W; 375 °C) microwave process was used to achieve a low sheet resistance, 78Ω/◻, and a high carrier concentration, 1.025 × 1020 P/cm3, which is close to the solid solubility limit of 2 × 1020 P/cm3.
Broadband multi-resonant strong field coherence breaking as a tool for single isomer microwave spectroscopy
Authors: Hernandez-Castillo A. O. , Abeysekera Chamara , Hays Brian M. , Zwier Timothy S.
Published: September 2016

Using standard hardware available in chirped-pulse Fourier transform microwave (CP-FTMW) spectroscopy, an experimental method is introduced to selectively extract from the microwave spectrum of an otherwise complicated multicomponent mixture a set of transitions due to a single component, thereby speeding spectral assignment. The method operates the broadband chirped-pulse used to excite the sample in the strong-field limit through a combination of high power and control of the sweep rate. A procedure is introduced that leads to selection of three transition frequencies that can be incorporated as a set of resonant sequential single-frequency microwave pulses that follow broadband chirped-pulse excitation, resulting in a reduction in the coherent signal from a set of transitions ascribable to the component of interest. The difference in the CP-FTMW spectrum with and without this set of multi-resonant single-frequency pulses produces a set of transitions that can confidently be assigned to a single component of the mixture, aiding the analysis of its spectrum. The scheme is applied to (i) selectively extract the spectrum of one of five singly 13C-subsituted isotopologues of benzonitrile in natural abundance, (ii) obtain the microwave spectra of the two structural isomers (E)- and (Z)-phenylvinylnitrile, and (iii) obtain conformer-specific microwave spectra of methylbutyrate.
Particle drift model for Z-pinch-driven magneto-Rayleigh-Taylor instability
Authors: Dan Jia Kun , Xu Qiang , Wang Kun Lun , Ren Xiao Dong , Huang Xian Bin
Published: September 2016

A theoretical model of Z-pinch driven magneto-Rayleigh-Taylor instability is proposed based on the particle drift point of view, which can explain the helical instability structure observed in premagnetized imploding liner experiments. It is demonstrated that all possible drift motions, including polarization drift, gradient drift, and curvature drift, which can lead to charge separations, each will attribute to an effective gravity acceleration. Theoretical predictions given by this model are dramatically different from those given by previous theories which have been readily recovered in the theory presented here as a limiting case. The theory shows qualitative agreement with available experimental data of the pitch angle and provides certain predictions to be verified.
Multiscale physics of rubber-ice friction
Authors: Tuononen Ari J. , Kriston András , Persson Bo
Published: September 2016

Ice friction plays an important role in many engineering applications, e.g., tires on icy roads, ice breaker ship motion, or winter sports equipment. Although numerous experiments have already been performed to understand the effect of various conditions on ice friction, to reveal the fundamental frictional mechanisms is still a challenging task. This study uses in situ white light interferometry to analyze ice surface topography during linear friction testing with a rubber slider. The method helps to provide an understanding of the link between changes in the surface topography and the friction coefficient through direct visualization and quantitative measurement of the morphologies of the ice surface at different length scales. Besides surface polishing and scratching, it was found that ice melts locally even after one sweep showing the refrozen droplets. A multi-scale rubber friction theory was also applied to study the contribution of viscoelasticity to the total friction coefficient, which showed a significant level with respect to the smoothness of the ice; furthermore, the theory also confirmed the possibility of local ice melting.
Generalized double-gradient model of flapping oscillations: Oblique waves
Authors: Korovinskiy D. B. , Kiehas S. A.
Published: September 2016

The double-gradient model of flapping oscillations is generalized for oblique plane waves, propagating in the equatorial plane. It is found that longitudinal propagation (ky = 0) is prohibited, while transversal (kx = 0) or nearly transversal waves should possess a maximum frequency, diminishing with the reduction of |ky/kx| ratio. It turns out that the sausage mode may propagate in a narrow range of directions only, |ky/kx|≫1. A simple analytical expression for the dispersion relation of the kink mode, valid in most part of wave numbers range, |ky/kx|<9, is derived.
Characterizing plasmoid reconnection by turbulence dynamics
Authors: Widmer F. , Büchner J. , Yokoi N.
Published: September 2016

In weakly dissipative plasmas, the plasmoid instability may lead, in principle, to fast magnetic reconnection through long current sheets. On the other hand, it is well known that weakly dissipative large-Reynolds-number plasmas easily become turbulent. We address the question of whether turbulence can enhance the reconnection rate of plasmoid-unstable current sheets by carrying out high resolution MHD simulations. Instead of resolving all scales down to dissipation, we utilize a turbulence model to investigate the influence of turbulence on the plasmoid instability. For this sake, we extend a Reynolds-averaged turbulence model expressing the energy, cross-helicity, and helicity due to the turbulence to a subgrid-scale (SGS) model of turbulence by means of a Gaussian filter. We then use the SGS turbulence model to investigate the contributions of the turbulent energy and cross-helicity to the plasmoid reconnection rate. In particular, we address the consequences of a finite guide magnetic field parallel to the reconnection electric field on the reconnection rate in terms of the residual turbulent helicity. To validate the turbulence model, we compare the SGS electromotive force with that obtained statistically from the high resolution simulations. This way, we characterize the influence of turbulence on the reconnection rate of plasmoid-unstable current sheets and attribute the plasmoid reconnection rate at large-magnetic-Reynolds-numbers to turbulence.
Piezoelectric tunable microwave superconducting cavity
Authors: C. Carvalho N. , Fan Y. , Tobar M. E.
Published: September 2016

In the context of engineered quantum systems, there is a demand for superconducting tunable devices, able to operate with high-quality factors at power levels equivalent to only a few photons. In this work, we developed a 3D microwave re-entrant cavity with such characteristics ready to provide a very fine-tuning of a high-Q resonant mode over a large dynamic range. This system has an electronic tuning mechanism based on a mechanically amplified piezoelectric actuator, which controls the resonator dominant mode frequency by changing the cavity narrow gap by very small displacements. Experiments were conducted at room and dilution refrigerator temperatures showing a large dynamic range up to 4 GHz and 1 GHz, respectively, and were compared to a finite element method model simulated data. At elevated microwave power input, nonlinear thermal effects were observed to destroy the superconductivity of the cavity due to the large electric fields generated in the small gap of the re-entrant cavity.
Ultra-high resolution steady-state micro-thermometry using a bipolar direct current reversal technique
Authors: Wu Jason Yingzhi , Wu Wei , Pettes Michael Thompson
Published: September 2016

The suspended micro-thermometry measurement technique is one of the most prominent methods for probing the in-plane thermal conductance of low dimensional materials, where a suspended microdevice containing two built-in platinum resistors that serve as both heater and thermometer is used to measure the temperature and heat flow across a sample. The presence of temperature fluctuations in the sample chamber and background thermal conductance through the device, residual gases, and radiation are dominant sources of error when the sample thermal conductance is comparable to or smaller than the background thermal conductance, on the order of 300 pW/K at room temperature. In this work, we present a high resolution thermal conductance measurement scheme in which a bipolar direct current reversal technique is adopted to replace the lock-in technique. We have demonstrated temperature resolution of 1.0–2.6 mK and thermal conductance resolution of 1.7–26 pW/K over a temperature range of 30–375 K. The background thermal conductance of the suspended microdevice is determined accurately by our method and allows for straightforward isolation of this parasitic signal. This simple and high-throughput measurement technique yields an order of magnitude improvement in resolution over similarly configured lock-in amplifier techniques, allowing for more accurate investigation of fundamental phonon transport mechanisms in individual nanomaterials.
Two-parameter twisted quantum affine algebras
Authors: Jing Naihuan , Zhang Honglian
Published: September 2016

We establish Drinfeld realization for the two-parameter twisted quantum affine algebras using a new method. The Hopf algebra structure for Drinfeld generators is given for both untwisted and twisted two-parameter quantum affine algebras, which include the quantum affine algebras as special cases.
All-solid-state micro-supercapacitors based on inkjet printed graphene electrodes
Authors: Li Jiantong , Mishukova Viktoriia , Östling Mikael
Published: September 2016

The all-solid-state graphene-based in-plane micro-supercapacitors are fabricated simply through reliable inkjet printing of pristine graphene in interdigitated structure on silicon wafers to serve as both electrodes and current collectors, and a following drop casting of polymer electrolytes (polyvinyl alcohol/H3PO4). Benefiting from the printing processing, an attractive porous electrode microstructure with a large number of vertically orientated graphene flakes is observed. The devices exhibit commendable areal capacitance over 0.1 mF/cm2 and a long cycle life of over 1000 times. The simple and scalable fabrication technique for efficient micro-supercapacitors is promising for on-chip energy storage applications in emerging electronics.
The diffusion and conduction of lithium in poly(ethylene oxide)-based sulfonate ionomers
Authors: LaFemina Nikki H. , Chen Quan , Colby Ralph H. , Mueller Karl T.
Published: September 2016

Pulsed field gradient nuclear magnetic resonance spectroscopy and dielectric relaxation spectroscopy have been utilized to investigate lithium dynamics within poly(ethylene oxide) (PEO)-based lithium sulfonate ionomers of varying ion content. The ion content is set by the fraction of sulfonated phthalates and the molecular weight of the PEO spacer, both of which can be varied independently. The molecular level dynamics of the ionomers are dominated by either Vogel-Fulcher-Tammann or Arrhenius behavior depending on ion content, spacer length, temperature, and degree of ionic aggregation. In these ionomers the main determinants of the self-diffusion of lithium and the observed conductivities are the ion content and ionic states of the lithium ion, which are profoundly affected by the interactions of the lithium ions with the ether oxygens of the polymer. Since many lithium ions move by segmental polymer motion in the ion pair state, their diffusion is significantly larger than that estimated from conductivity using the Nernst-Einstein equation.
Engineering of the Curie temperature of epitaxial Sr1−xBaxTiO3 films via strain
Authors: Dai Y. , Schubert J. , Hollmann E. , Mussler G. , Wördenweber R.
Published: September 2016

The impact of strain on the structural and electrical properties of epitaxial Sr1−xBaxTiO3 films grown on single crystalline DyScO3 (110), TbScO3 (110), and GdScO3 (110) substrates is presented. X-ray diffraction measurements demonstrate that all films are grown epitaxially. The tensile in-plane strain is only partially compensated by a contraction of the out-of-plane lattice parameter. As a result, the volume of the unit cell of the Sr1−xBaxTiO3 film increases due to the tensile strain, and the resulting Poisson ratio of the film is ν ≈ 0.33, which is larger than but still close to the literature values of ν ≈ 0.23 for unstrained defect-free SrTiO3. The Curie temperature derived from the temperature dependence of the in-plane dielectric response leads to a strain-temperature phase diagram for the epitaxial Sr1−xBaxTiO3 films. The experimental data show a deviation from the linear dependence predicted by the Landau thermodynamic theory for large strain (>1.2%). However, using the equilibrium thermodynamic analysis, we can demonstrate that this deviation arises from the relaxation of the strain due to defect formation in the film. The result reveals that in addition to the nominal misfit strain, the defect formation strongly affects the effective strain and, thus, the dielectric response of epitaxially grown ferroelectric films.
Effect of NiO crystallinity on forming characteristics in Pt/NiO/Pt cells as resistive switching memories
Authors: Nishi Yusuke , Kimoto Tsunenobu
Published: September 2016

Resistive switching (RS) in metal/oxide/metal stack structures plays a key role in resistive RAM. The formation and rupture of conductive filaments have been widely accepted as an origin of RS mechanism especially in binary transition metal oxides. Forming exhibits some analogies with a dielectric breakdown of SiO2 thin films. In this study, Time-Dependent Forming (TDF) characteristics of Pt/NiO/Pt stack structures have been investigated. The results revealed that the formation of conductive filaments at the forming process by applying constant voltage followed a weakest-link theory and that the weakest spots were almost randomly distributed in NiO thin films according to the Poisson statistics. Furthermore, the distribution of TDF characteristics depends on NiO crystallinity. A small variation of initial resistance tends to result in a large variation of time to forming and vice versa.
Extraction of state-resolved information from systems with a fractional number of electrons within the framework of time-dependent density functional theory
Authors: Wang Feng , Yao Yugui , Calvayrac Florent , Zhang Fengshou
Published: September 2016

The determination of the state-resolved physical information within the framework of time-dependent density functional theory has remained a widely open question. We demonstrated the ability to extract the state-resolved probability from the knowledge of only the time-dependent density, which has been used as the basic variable within the time-dependent density functional theory, with the help of state-resolved single-electron capture experiments for collisions of protons on helium in the energy range of 2-100 keV/amu. The present theoretical results for capture into states of H(1s), H(2s), and H(2p) are in good agreement with the most sophisticated experimental results of H+ + He(1s2) system, validating our approach and numerical implementation.
Efficient method for calculations of ro-vibrational states in triatomic molecules near dissociation threshold: Application to ozone
Authors: Teplukhin Alexander , Babikov Dmitri
Published: September 2016

A method for calculations of rotational-vibrational states of triatomic molecules up to dissociation threshold (and scattering resonances above it) is devised, that combines hyper-spherical coordinates, sequential diagonalization-truncation procedure, optimized grid DVR, and complex absorbing potential. Efficiency and accuracy of the method and new code are tested by computing the spectrum of ozone up to dissociation threshold, using two different potential energy surfaces. In both cases good agreement with results of previous studies is obtained for the lower energy states localized in the deep (∼10 000 cm−1) covalent well. Upper part of the bound state spectrum, within 600 cm−1 below dissociation threshold, is also computed and is analyzed in detail. It is found that long progressions of symmetric-stretching and bending states (up to 8 and 11 quanta, respectively) survive up to dissociation threshold and even above it, whereas excitations of the asymmetric-stretching overtones couple to the local vibration modes, making assignments difficult. Within 140 cm−1 below dissociation threshold, large-amplitude vibrational states of a floppy complex O⋯O2 are formed over the shallow van der Waals plateau. These are assigned using two local modes: the rocking-motion and the dissociative-motion progressions, up to 6 quanta in each, both with frequency ∼20 cm−1. Many of these plateau states are mixed with states of the covalent well. Interestingly, excitation of the rocking-motion helps keeping these states localized within the plateau region, by raising the effective barrier.
Angular and energy distributions of fragment ions in dissociative double photoionization of acetylene molecules in the 31.9-50.0 eV photon energy range
Authors: Falcinelli Stefano , Alagia Michele , Farrar James M. , Kalogerakis Konstantinos S. , Pirani Fernando , Richter Robert , Schio Luca , Stranges Stefano , Rosi Marzio , Vecchiocattivi Franco
Published: September 2016

The two-body dissociation reactions of the dication C2H2+2, initiated via double ionization of acetylene molecules by photons in the energy range 31.9-50.0 eV, have been studied by coupling photoelectron-photoion-photoion coincidence and ion imaging techniques. The angular distributions and kinetic energy of product ions, measured in the 31.9-50.0 eV energy range, exhibit significant differences for the three leading dissociation reactions with respect to a previous investigation carried out at a fixed energy of 39.0 eV, providing thus new information on the dynamical evolution of the system. The analysis of the results indicates that such dissociation reactions occur with a different mechanism. In particular, the symmetric dissociation in two CH+ ions is characterized by different dynamics, and the anisotropy of the angular distribution of ionic products increases with photon energy in a more pronounced way than the other two reactions. Moreover, the kinetic energy distribution of the symmetric dissociation reaction exhibits several components that change with photon energy. The new experimental findings cast light on the microscopic evolution of the system and can provide a laboratory reference for new theoretical calculations on specific features of the multidimensional potential energy surface, namely, the structure, energy and symmetry of dication states, the electronic state of dissociation products, energy barriers and their dependence on the geometry of the intermediate state.
The 1D parabolic-parabolic Patlak-Keller-Segel model of chemotaxis: The particular integrable case and soliton solution
Authors: Shubina Maria
Published: September 2016

In this paper, we investigate the one-dimensional parabolic-parabolic Patlak-Keller-Segel model of chemotaxis. For the case when the diffusion coefficient of chemical substance is equal to two, in terms of travelling wave variables the reduced system appears integrable and allows the analytical solution. We obtain the exact soliton solutions, one of which is exactly the one-soliton solution of the Korteweg-de Vries equation.
Mediating Fano losses in plasmonic scatterers by tuning the dielectric environment
Authors: Powell A. W. , Smith J. M.
Published: September 2016

Scattering from metal nanoparticles above a high index substrate has the potential to significantly enhance light trapping in thin film devices with minimal additional cost. However, the benefits of this approach are currently limited by short wavelength losses from Fano resonances arising due to interference between the plasmon modes in a nanoparticle. In this paper, the effect of particle-substrate interactions on the observed Fano behaviour is explored in detail, using finite-difference time-domain simulations and an analytical model. Several approaches to mitigate the Fano loss are explored, and it is found that overcoating the particle with a thin dielectric film represents by far the most effective way to remove Fano losses whilst keeping broadband forward scattering high.
Development of an advanced microfluidic micropipette aspiration device for single cell mechanics studies
Authors: Lee Lap Man , Lee Jin Woo , Chase Danielle , Gebrezgiabhier Daniel , Liu Allen P.
Published: September 2016

Various micro-engineered tools or platforms have been developed recently for cell mechanics studies based on acoustic, magnetic, and optical actuations. Compared with other techniques for single cell manipulations, microfluidics has the advantages with simple working principles and device implementations. In this work, we develop a multi-layer microfluidic pipette aspiration device integrated with pneumatically actuated microfluidic control valves. This configuration enables decoupling of cell trapping and aspiration, and hence causes less mechanical perturbation on trapped single cells before aspiration. A high trapping efficiency is achieved by the microfluidic channel design based on fluid resistance model and deterministic microfluidics. Compared to conventional micropipette aspiration, the suction pressure applied on the aspirating cells is highly stable due to the viscous nature of low Reynolds number flow. As a proof-of-concept of this novel microfluidic technology, we built a microfluidic pipette aspiration device with 2 × 13 trapping arrays and used this device to measure the stiffness of a human breast cancer cell line, MDA-MB-231, through the observation of cell deformations during aspiration. As a comparison, we studied the effect of Taxol, a FDA-approved anticancer drug on single cancer cell stiffness. We found that cancer cells treated with Taxol were less deformable with a higher Young's modulus. The multi-layer microfluidic pipette aspiration device is a scalable technology for single cell mechanophenotyping studies and drug discovery applications.
Hotspot-engineered quasi-3D metallic network for surface-enhanced Raman scattering based on colloid monolayer templating
Authors: Du Wei , Liu Long , Gu Ping , Hu Jingguo , Zhan Peng , Liu Fanxin , Wang Zhenlin
Published: September 2016

A hotspot-engineered quasi-3D metallic network with controllable nanogaps is purposed as a high-quality surface-enhanced Raman scattering (SERS) substrate, which is prepared by a combination of non-close-packed colloid monolayer templating and metal physical deposition. The significant SERS effect arises from a strongly enhanced local electric field originating from the ultra-small-gaps between neighboring metal-caps and tiny interstices and between the metal-caps and the metal-bumps on the base, which is recognized by the numerical simulation. A remarkable average SERS enhancement factor of up to 1.5 × 108 and a SERS intensity relative standard deviation (RSD) of 10.5% are achieved by optimizing the nanogap size to sub-10 nm scale, leading to an excellent capability for Raman detection, which is represented by the clearly identified SERS signal of the Rhodamine 6G solution with a fairly low concentration of 1 nM.
Bipolar spin-valley diode effect in a silicene magnetic junction
Authors: Zhai Xuechao , Zhang Sihao , Zhao Ying , Zhang Xiaoyu , Yang Zhihong
Published: September 2016

Silicene has attracted much attention recently due to the electrons' multiple degrees of freedom, specifically for spin and valley. We here demonstrate that a bipolar spin-valley diode effect can be driven and controlled by applying longitudinal biases through a silicene ferromagnetic-field/interlayer-electric-field junction. This effect indicates that only one-spin (the other spin) electrons from one valley (the other valley) contribute to the conductance under positive (negative) biases, originating from the specific band-matching tunneling mechanism. All the forbidden channels are induced by either spin-mismatch or spin-valley dependent bandgaps. It is also found that, by reversing the direction of interlayer electric field, the conductive valley can be switched to the other while the spin orientation is reserved. Furthermore, all the possible spin-valley configurations of conductance, contributed by single spin and single valley, can be completely turned “on” or “off” only by tuning the bias and the electric field. These results suggest that silicene can be a good candidate for future quantum information processing in spin-valley logic circuits.
Direct-write graded index materials realized in protein hydrogels
Authors: Kaehr Bryan , Scrymgeour David A.
Published: September 2016

The ability to create optical materials with arbitrary index distributions would prove transformative for optics design and applications. However, current fabrication techniques for graded index (GRIN) materials rely on diffusion profiles and therefore are unable to realize arbitrary distribution GRIN design. Here, we demonstrate the laser direct writing of graded index structures in protein-based hydrogels using multiphoton lithography. We show index changes spanning a range of 10−2, which is comparable with laser densified glass and polymer systems. Further, we demonstrate the conversion of these written density variation structures into SiO2, opening up the possibility of transforming GRIN hydrogels to a wide range of material systems.
Bulk InAsxSb1-x nBn photodetectors with greater than 5μm cutoff on GaSb
Authors: Baril Neil , Brown Alexander , Maloney Patrick , Tidrow Meimei , Lubyshev Dmitri , Qui Yueming , Fastenau Joel M. , Liu Amy W. K. , Bandara Sumith
Published: September 2016

Mid-wavelength infrared nBn photodetectors based on bulk InAsxSb1-x absorbers with a greater than 5 μm cutoff grown on GaSb substrates are demonstrated. The extended cutoff was achieved by increasing the lattice constant of the substrate from 6.09 to 6.13 Å using a 1.5 μm thick AlSb buffer layer to enable the growth of bulk InAs0.81Sb0.19 absorber material. Transitioning the lattice to 6.13 Å also enables the use of a simple binary AlSb layer as a unipolar barrier to block majority carrier electrons and reduce dark current noise. Individual test devices with 4 μm thick absorbers displayed 150 K dark current density, cutoff wavelength, and quantum efficiency of 3 × 10−5 A/cm2, 5.31 μm, and 44% at 3.4 μm, respectively. The instantaneous dark current activation energy at a given bias and temperature is determined via Arrhenius analysis from the Dark current vs. temperature and bias data, and a discussion of valence band alignment between the InAsxSb1-x absorber and AlSb barrier layers is presented.
Topological phase in oxidized zigzag stanene nanoribbons
Authors: Modarresi Mohsen , Kuang Wei Bin , Kaloni Thaneshwor P. , Roknabadi Mahmood Rezaee , Schreckenbach Georg
Published: September 2016

First-principles and semi-empirical tight binding calculations were performed to understand the adsorption of oxygen on the surface of two dimensional (2D) and zigzag stanene nano-ribbons. The intrinsic spin-orbit interaction is considered in the Kane-Mele tight binding model. The adsorption of an oxygen atom or molecule on the 2D stanene opens an electronic energy band gap. We investigate the helical edge states and topological phase in the pure zigzag stanene nano-ribbons. The adsorption of oxygen atoms on the zigzag stanene nano-ribbons deforms the helical edge states at the Fermi level which causes topological (non-trivial) to trivial phase transition. The structural stability of the systems is checked by performing Γ-point phonon calculations. Specific arrangements of adsorbed oxygen atoms on the surface of zigzag stanene nano-ribbons conserve the topological phase which has potential applications in future nano-electronic devices.
Response of different fodder legume species to Colletotrichum trifolii
Authors: Jacob Irene , Hartmann Stephan , Struck Christine
Published: September 2016

Colletotrichum trifolii, the causal agent of southern anthracnose, is a major fungal disease in red clover (Trifolium pratense) and lucerne (alfalfa, Medicago sativa), with varietal differences reported. However, results on the reactions of other fodder legumes grown in Central Europe are limited. In this study, a greenhouse test for resistance evaluated the response of T. repens, T. alexandrinum, T. incarnatum, T. resupinatum, Lotus corniculatus, M. lupulina, Onobrychis viciifolia, Vicia sativa, and V. villosa against C. trifolii compared with M. sativa. Conditions of the test were not suitable for T. alexandrinum and the two Vicia species; however, T. repens, T. resupinatum, and L. corniculatus proved highly resistant against the fungus. The other species showed mean plant survival rates of 61.5–84.7%.
Effects of shed modifications on ewe reproductive performance and lamb growth rate in Inner Mongolia
Authors: Zhang X. Q. , Kemp D. , Hou X. Y. , Langford C. M. , Wang K. , Yan W. H.
Published: September 2016

The effects of warm sheds on the performance of ewes and their lambs in winter are poorly understood. The aim of the present study was to examine the effects of traditional sheds (TS + grazing) and modified warm sheds (WS, no grazing) on the reproductive performance of ewes (as well as their liveweight) and their lambs during the winter–spring period. Cross-bred ewes (n = 120) were randomly assigned to two treatments, either TS (+ grazing) or WS (no grazing), during the winter–spring period of 2011, 2012 and 2013. This study was conducted on two adjacent farms with the two treatments applied on each. The ewes in the TS treatment were grazed continuously on pasture in the day and housed in traditional sheds each evening, whereas the ewes in the WS treatment were not grazed. The animals in each treatment were fed the same amount of feed. Ewes housed in the WS group had a higher liveweight and lower weight loss than ewes in the TS group (P = 0.004 and 0.005 respectively); over the 3 years, the weight loss of the ewes in both groups was worst in the first 2 months (December–January) compared with the later 2 months, and was significantly alleviated after the first year (2011; P < 0.001). Lamb liveweight and gain were higher in the WS than TS treatment group (P < 0.001) and the growth rates of the lambs increased continuously as shed temperatures increased. Lamb weight gain and birthweight increased significantly with increasing years of the experiment (P < 0.001). There were more lambs born in the WS than in the TS groups (P = 0.020), with higher survival and twinning rates (P < 0.05). As shed temperatures increased, lambing, survival and twinning rates increased continuously. Therefore, keeping livestock in warm sheds during the winter and spring period will lift animal productivity, leading to improved household incomes. Elimination of winter grazing will reduce damage to already degraded grasslands and will assist herders to develop more positive attitudes towards animal production enterprises.
Focal colors across languages are representative members of color categories
Authors: Abbott Joshua T. , Griffiths Thomas L. , Regier Terry
Published: September 2016

Significance

The best examples of color terms across languages are often held to reflect universal focal colors in the opponent pairs red vs. green and yellow vs. blue. An opposing view holds that best examples reflect categories that are determined by local linguistic convention. We argue for a synthesis of these two proposals. We show that best examples of color terms across languages can be predicted from color term extensions using a statistical model that indicates which samples are most representative of a distribution. This model accounts for universal tendencies in best example choices across languages, and also accounts for cross-language variation. Our findings suggest that general statistical principles may illuminate fundamental aspects of color naming across languages.
WASH drives early recycling from macropinosomes and phagosomes to maintain surface phagocytic receptors
Authors: Buckley Catherine M. , Gopaldass Navin , Bosmani Cristina , Johnston Simon A. , Soldati Thierry , Insall Robert H. , King Jason S.
Published: September 2016

Significance

Macropinocytosis is a way for cells to engulf large volumes of their extracellular fluid. This process allows immune cells to sense their environment and detect antigens, but can also supply nutrients to both cancer cells and some unicellular organisms. However, little is known about the fate of the membrane components internalized via macropinosomes. This study explains how cells avoid the bulk digestion of their surface proteins. We identify several core components of this pathway and show that they are required for early recycling from macropinosomes. We demonstrate that this pathway is crucial for cells undergoing continuous macropinocytosis to maintain surface protein levels and is therefore physiologically important for such cells to sustain normal functions.
Crystal structures and dynamical properties of dense CO
2
Authors: Yong Xue , Liu Hanyu , Wu Min , Yao Yansun , Tse John S. , Dias Ranga , Yoo Choong-Shik
Published: September 2016

Significance

Using multiple theoretical techniques, the temperature and pressure dependence of the structures and dynamics of dense CO
2
were investigated. Near the transition to the extended structure, CO
2
molecules were found to exhibit large-amplitude bending vibrations. A 4-coordinated
Pna
2
1
structure (CO
2
-V′) with a diffraction pattern similar to CO
2
-V (
P2

1

2

1

2

1

) was found. Both CO
2
-V and -V′ are predicted to be metastable at ambient pressure. This result is in agreement with the experimental recovery of CO
2
-V below 200 K at ambient pressure. This 4-coordinated structure formed from main group molecules was recovered from high pressure. Both recovered fully extended CO
2
solids possess high- energy density and hardness.
Nanoparticles size-dependently initiate self-limiting NETosis-driven inflammation
Authors: Muñoz Luis E. , Bilyy Rostyslav , Biermann Mona H. C. , Kienhöfer Deborah , Maueröder Christian , Hahn Jonas , Brauner Jan M. , Weidner Daniela , Chen Jin , Scharin-Mehlmann Marina , Janko Christina , Friedrich Ralf P. , Mielenz Dirk , Dumych Tetiana , Lootsik Maxim D. , Schauer Christine , Schett Georg , Hoffmann Markus , Zhao Yi , Herrmann Martin
Published: September 2016

Significance

The current widespread exposure of humans to natural as well as man-made nanomaterials due to the deployment of nanoparticles (NPs) as food additives, as vaccine- or drug-delivery vehicles, and in diagnostic procedures encourages the evaluation of their interaction with the innate immune system. Understanding how organisms cope with hydrophobic and chemically inert particulate matter, which is excluded from metabolic processing, is of major importance for interpreting the responses associated with the use of NPs in the biosphere. The containment of NPs within neutrophil-derived aggregates locally orchestrates the resolution of inflammation. Overriding this mechanism bears the risk of inducing chronic inflammation and causing tissue damage.
Mechanism and energetics of 〈c + a〉 dislocation cross-slip in hcp metals
Authors: Wu Zhaoxuan , Curtin W. A.
Published: September 2016

Significance

For all hexagonal close-packed (hcp) metals, the ability to plastically deform in the crystallographic c axis is crucial for achieving high ductility and high fracture toughness.

〈

c
+
a

〉

dislocation slip is the only sustainable mechanism to accommodate c-axis strain, but is difficult across the family of hcp metals. We reveal the mechanism, energy barrier, and unusual stress dependence of

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c
+
a

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dislocation cross-slip in Mg, using atomistic simulations. Our results provide mechanistic insights into

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c
+
a

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cross-slip behavior, rationalize observed changes in pyramidal I/II slip stability, enable predictions of slip trends across the family of hcp metals, and suggest that applied stresses and/or precise solid solution alloying can optimize cross-slip and enhance c-axis strain capacity, which can ultimately guide design of improved hcp alloys.
Three-dimensional localization of T-cell receptors in relation to microvilli using a combination of superresolution microscopies
Authors: Jung Yunmin , Riven Inbal , Feigelson Sara W. , Kartvelishvily Elena , Tohya Kazuo , Miyasaka Masayuki , Alon Ronen , Haran Gilad
Published: September 2016

Significance

T lymphocytes play a central role in cell-mediated immunity. Their surfaces are covered by narrow and short protrusions called microvilli. It is not known whether there is a role for microvilli in the immune response. To shed light on this question, we probed the location of T-cell receptors (TCRs), the molecules that initiate the immune response of T cells, with respect to the 3D structure of microvilli. Superresolution optical microscopy showed that TCRs are highly concentrated on microvilli. Previous studies stressed the role of small clusters of TCRs in the immune process; our study provides a natural explanation as to how these clusters form.
Critical reappraisal confirms that Mitofusin 2 is an endoplasmic reticulum–mitochondria tether
Authors: Naon Deborah , Zaninello Marta , Giacomello Marta , Varanita Tatiana , Grespi Francesca , Lakshminaranayan Sowmya , Serafini Annalisa , Semenzato Martina , Herkenne Stephanie , Hernández-Alvarez Maria Isabel , Zorzano Antonio , De Stefani Diego , Dorn Gerald W. , Scorrano Luca
Published: September 2016

Significance

Organelles engage in heterotypic interactions crucial for metabolic and signaling cascades. The best-studied case of this heterotypic interaction is that between the mitochondria and endoplasmic reticulum (ER), crucial for transfer of lipids and especially Ca
2+
between the two organelles. The original discovery that the mitochondria-shaping protein Mitofusin 2 (Mfn2) physically tethers the ER to mitochondria was recently challenged. Here, electron microscopy and fluorescent probes of organelle proximity provide definitive evidence that constitutive or acute Mfn2 ablation increases the distance between the ER and mitochondria. Functionally, this process reduces mitochondrial Ca
2+
uptake without altering the mitochondrial Ca
2+
uniporter complex in multiple tissues. Thus, the discoveries of the role of ER–mitochondria juxtaposition in cell biology based on Mfn2 as a tool remain unchallenged.
Molecular organization of cytokinesis nodes and contractile rings by super-resolution fluorescence microscopy of live fission yeast
Authors: Laplante Caroline , Huang Fang , Tebbs Irene R. , Bewersdorf Joerg , Pollard Thomas D.
Published: September 2016

Significance

Cell division occurs by the assembly and constriction of a ring of actin and myosin; however, the organization of proteins within cytokinetic apparatus is still unknown. Without better information about the organization of contractile rings, we cannot understand how they assemble or constrict. In fission yeast, cytokinetic proteins are first recruited around the equator as cortical spots, called nodes, that coalesce into a ring. Here we used high-speed quantitative fluorescence photoactivation localization microscopy to obtain a molecular model of this basic cytokinetic unit. Nodes are discrete structures with distinct distributions of six different proteins. Nodes persist in contractile rings and move around the circumference as the ring constricts.
Evolutionary learning of adaptation to varying environments through a transgenerational feedback
Authors: Xue BingKan , Leibler Stanislas
Published: September 2016

Significance

Phenotypic diversification, a form of evolutionary bet hedging, is observed in many biological systems, ranging from isogenic bacteria to cell populations in a tumor. Such phenotypic diversity is adaptive only if it matches the statistics of local environmental variation. Often, the timescale of environmental variation can be much longer than the lifespan of individual organisms. Then how could organisms collect long-term environmental information to modulate their phenotypic diversity? We propose here a general mechanism of “evolutionary learning,” which could overcome the mismatch between the two timescales. The learning mechanism can in principle be realized through known molecular processes of epigenetic inheritance, suggesting experimental directions to probe the evolutionary significance of such processes.
Origin of the multiple configurations that drive the response of δ-plutonium’s elastic moduli to temperature
Authors: Migliori Albert , Söderlind Per , Landa Alexander , Freibert Franz J. , Maiorov Boris , Ramshaw B. J. , Betts Jon B.
Published: September 2016

Significance

Our measurements have shown that the face-centered cubic (δ)-phase of plutonium exhibits little or no volume change but softens drastically as temperature rises over a very broad range. This behavior constrains any microscopic theory of plutonium to require that more than one thermodynamically accessible configuration exists, that the higher energy one has a smaller volume, and contrary to most models, the higher energy, smaller volume configuration must be more compressible. Until the recent neutron-scattering discovery of dynamic magnetism in plutonium, no evidence for such configurations existed. With that discovery, we are able to justify our microscopic theory that captures the observed neutron-scattering and temperature behavior of δ-plutonium.
Structural basis for norovirus neutralization by an HBGA blocking human IgA antibody
Authors: Shanker Sreejesh , Czakó Rita , Sapparapu Gopal , Alvarado Gabriela , Viskovska Maria , Sankaran Banumathi , Atmar Robert L. , Crowe James E. , Estes Mary K. , Prasad B. V. Venkataram
Published: September 2016

Significance

Attachment to cellular glycans is a critical process in cell entry for several viruses. Antibodies that block this essential step can serve as neutralizing antibodies. Among human noroviruses (NoVs), serum antibodies that block histo-blood group antigen (HBGA) binding serve as correlates of protection. Escape from neutralization with evolving human NoVs (HuNoVs) through antigenic variation and differential HBGA binding is suggested to form a basis for the emergence of new strains. Currently, we are aware of no structural insights into antibody-mediated HBGA blockade or neutralization, or how emerging strains escape such neutralization. Our study reveals how a human IgA monoclonal antibody binds and blocks HBGA binding and indicates how other strains escape host immunity, laying the structural framework for understanding the immune correlates of protection against HuNoVs.
BMI1–UBR5 axis regulates transcriptional repression at damaged chromatin
Authors: Sanchez Anthony , De Vivo Angelo , Uprety Nadima , Kim Jonghwan , Stevens Stanley M. , Kee Younghoon
Published: September 2016

Significance

The BMI1-containing Polycomb Repressive Complex is an important gene silencer during development, stem cell maintenance, and cancer progression. BMI1 is also involved in DNA damage response, but its downstream mechanism is unclear. Here we identified UBR5 as a downstream factor whose chromatin recruitment is regulated by BMI1. We showed that BMI1 and UBR5 repress the RNA polymerase II (Pol II) elongation and nascent RNA synthesis at UV-induced DNA lesions. UBR5 associates with and regulates the abundance of the histone chaperon complex FACT at damaged chromatin and regulates elongation of Pol II at the lesions. Thus, our studies identify a pathway that regulates the damage-induced transcriptional repression that is governed by BMI1.
Transparent conducting oxide induced by liquid electrolyte gating
Authors: ViolBarbosa Carlos , Karel Julie , Kiss Janos , Gordan Ovidiu-dorin , Altendorf Simone G. , Utsumi Yuki , Samant Mahesh G. , Wu Yu-Han , Tsuei Ku-Ding , Felser Claudia , Parkin Stuart S. P.
Published: September 2016

Significance

Highly conducting transparent oxides are widely used as electrodes in various electronic devices where optical transparency through a low-resistance electrode is needed. Here, we show that highly conducting transparent oxide films can be formed by electrolyte gating of thin films of tungsten oxide, WO
3
, that are initially insulating. Optical and electronic structure measurements show that the films are transparent in the visible spectrum before gating, due to the significant electronic band gap of ∼3.0 eV. No significant change in the band gap is found on gating the films to the metallic state so that the films remain transparent in the visible spectral region. Thus electrolyte gating of insulating oxides is a means of obtaining new classes of transparent conducting electrodes.
Network architecture of the cerebral nuclei (basal ganglia) association and commissural connectome
Authors: Swanson Larry W. , Sporns Olaf , Hahn Joel D.
Published: September 2016

Significance

The cerebral nuclei together with the cerebral cortex form the cerebral hemispheres that are critically important for the control of voluntary behavior and motivation. Network analysis of microscopic connectional data collected since the 1970s in a small, intensely studied mammal provides a new way to understand overall design features of circuitry coordinating activity in the various parts of the cerebral nuclei on both sides of the brain. Basically, intracerebral nuclei circuitry is organized into four modules on each side of the brain, with connections within and between modules on one side being quite dense and connections between the cerebral nuclei on either side being quite sparse. The results provide insight into cerebral nuclei structure and function.