bluuebunny/crossref_metadata_2025 huggingface dataset:
Toward a mild dehydroformylation using base-metal catalysis
Authors: Abrams Dylan J. , West Julian G. , Sorensen Erik J.
Published: November 2016

Dehydroformylation, a challenging, underexplored reaction, can be performed under mild conditions using a designed cooperative base metal catalyst system.
Flexible, highly conductive, and free-standing reduced graphene oxide/polypyrrole/cellulose hybrid papers for supercapacitor electrodes
Authors: Wan Caichao , Jiao Yue , Li Jian
Published: November 2016

A hybrid paper consisting of a cellulose fiber frame supporting interpenetrated RGO–PPy nanoacrhitectures served as a free-standing and binder-free supercapacitor electrode.
Multishell structured magnetic nanocomposites carrying a copolymer of pyrrole–thiophene for highly selective Au(iii) recovery
Authors: Zhu Mingying , Zhang Wei , Li Yan , Gai Ligang , Zhou Jianhua , Ma Wanyong
Published: November 2016

Magnetic nanocomposites with surface containing multiform heteroatoms have great potential for metal-ion recovery with a high throughput.
Catalyzed KSiH3as a reversible hydrogen storage material
Authors: Janot R. , Tang W. S. , Clémençon D. , Chotard J.-N.
Published: November 2016

Solid-state hydrogen storage through the reversible formation of metallic hydrides is a key issue for the development of hydrogen as an energy vector. Here the hydrogen storage kinetics of the reaction between KSi and KSiH3have been strongly enhanced by catalyst addition. The reaction is perfectly reversible near ambient conditions with a 4.1 wt% hydrogen storage capacity.
Pt–CoP/C as an alternative PtRu/C catalyst for direct methanol fuel cells
Authors: Chang Jinfa , Feng Ligang , Jiang Kun , Xue Huaiguo , Cai Wen-Bin , Liu Changpeng , Xing Wei
Published: November 2016

A novel Pt–CoP/C electrocatalyst was developed for direct methanol fuel cells. This catalyst showed superior power density to commercial Pt/C and PtRu/C catalysts. In situ ATR-SEIRAS technology revealed that the presence of CoP in the Pt-based catalyst can promote the methanol oxidation to final CO2 products.
Correction: Modeling composite electrolytes for low-temperature solid oxide fuel cell application: structural, vibrational and electronic features of carbonate–oxide interfaces
Authors: Ricca Chiara , Grishin Andrey , Ringuedé Armelle , Cassir Michel , Adamo Carlo , Labat Frédéric
Published: November 2016

Correction for ‘Modeling composite electrolytes for low-temperature solid oxide fuel cell application: structural, vibrational and electronic features of carbonate–oxide interfaces’ by Chiara Ricca et al., J. Mater. Chem. A, 2016, DOI: 10.1039/c6ta06827h.
Correction: Critical advances for the iron molten air battery: a new lowest temperature, rechargeable, ternary electrolyte domain
Authors: Liu Shuzhi , Li Xin , Cui Baochen , Liu Xianjun , Hao Yulan , Guo Qi , Xu Peiqiang , Licht Stuart
Published: November 2016

Correction for ‘Critical advances for the iron molten air battery: a new lowest temperature, rechargeable, ternary electrolyte domain’ by Shuzhi Liu et al., J. Mater. Chem. A, 2015, 3, 21039–21043.
NIR-driven graphitic-phase carbon nitride nanosheets for efficient bioimaging and photodynamic therapy
Authors: Feng Lili , He Fei , Yang Guixin , Gai Shili , Dai Yunlu , Li Chunxia , Yang Piaoping
Published: November 2016

Photodynamic therapy (PDT) is a noninvasive and promising anticancer therapy modality that utilizes the photochemical reactions of photosensitizers, upon irradiation at a specific wavelength, to yield reactive oxygen species (ROS) to impair malignant cancer cells.
Synergistic effects of particulate matter (PM2.5) and sulfur dioxide (SO2) on neurodegeneration via the microRNA-mediated regulation of tau phosphorylation
Authors: Ku Tingting , Chen Minjun , Li Ben , Yun Yang , Li Guangke , Sang Nan
Published: November 2016

Because air pollution is a complex mixture of pollutants, understanding the health risks requires an evaluation of their combined effects rather than predictions based on the single chemicals alone.
Influence of Hearing Risk Information on the Motivation and Modification of Personal Listening Device Use
Authors: Serpanos Yula C. , Berg Abbey L. , Renne Brittany
Published: November 2016

Purpose

The purpose of this study was (a) to investigate the behaviors, knowledge, and motivators associated with personal listening device (PLD) use and (b) to determine the influence of different types of hearing health risk education information (text with or without visual images) on motivation to modify PLD listening use behaviors in young adults.

Method

College-age students (
N
= 523) completed a paper-and-pencil survey tapping their behaviors, knowledge, and motivation regarding listening to music or media at high volume using PLDs. Participants rated their motivation to listen to PLDs at lower volume levels following each of three information sets: text only, behind-the-ear hearing aid image with text, and inner ear hair cell damage image with text.

Results

Acoustically pleasing and emotional motives were the most frequently cited (38%–45%) reasons for listening to music or media using a PLD at high volume levels. The behind-the-ear hearing aid image with text information was significantly (
p
< .0001) more motivating to participants than text alone or the inner ear hair cell damage image with text.

Conclusions

Evocative imagery using hearing aids may be an effective approach in hearing protective health campaigns for motivating safer listening practices with PLDs in young adults.
Laboratory detection of the rotational-tunnelling spectrum of the hydroxymethyl radical, CH2OH
Authors: Bermudez C. , Bailleux S. , Cernicharo J.
Published: November 2016

Context. Of the two structural isomers of CH3O, methoxy is the only radical whose astronomical detection has been reported through the observation of several rotational lines at 2 and 3 mm wavelengths. Although the hydroxymethyl radical, CH2OH, is known to be thermodynamically the most stable (by ~3300 cm-1), it has so far eluded rotational spectroscopy presumably because of its high chemical reactivity.

Aims. Recent high-resolution (~10 MHz) sub-Doppler rovibrationally resolved infrared spectra of CH2OH (symmetric CH stretching a-type band) provided accurate ground vibrational state rotational constants, thus reviving the quest for its millimeter-wave spectrum in laboratory and subsequently in space.

Methods. The search and assignment of the rotational spectrum of this fundamental species were guided by our quantum chemical calculations and by using rotational constants derived from high-resolution IR data. The hydroxymethyl radical was produced by hydrogen abstraction from methanol by atomic chlorine.

Results. Ninety-six b-type rotational transitions between the v = 0 and v = 1 tunnelling sublevels involving 25 fine-structure components of Q branches (with Ka = 1 ← 0) and 4 fine-structure components of R branches (assigned to Ka = 0 ← 1) were measured below 402 GHz. Hyperfine structure alternations due to the two identical methylenic hydrogens were observed and analysed based on the symmetry and parity of the rotational levels. A global fit including infrared and millimeter-wave lines has been conducted using Pickett’s reduced axis system Hamiltonian. The recorded transitions (odd ΔKa) did not allow us to evaluate the Coriolis tunnelling interaction term. The comparison of the experimentally determined constants for both tunnelling levels with their computed values secures the long-awaited first detection of the rotational-tunnelling spectrum of this radical. In particular, a tunnelling rate of 139.73 ± 0.10 MHz (4.6609(32) × 10-3 cm-1) was obtained along with the rotational constants, electron spin-rotation interaction parameters and several hyperfine coupling terms.

Conclusions. The laboratory characterization of CH2OH by millimeter-wave spectroscopy now offers the possibility for its astronomical detection for the first time.
A time-lag model for biogas production by anaerobic digestion
Authors: Mondal Chanchal , Das Aritra , Chatterjee Siddharth G.
Published: November 2016

This work presents a simple time-lag model for biogas production from anaerobic digestion of organic wastes (biomass) in a batch digester. The model has the ability of predicting the S-shaped nature of the cumulative biogas yield with retention time that is commonly observed experimentally. The model is calibrated against biogas production data from anaerobic digestion of three types of organic waste: OFMSW (organic fraction of municipal solid waste), FVW (fruit and vegetable waste) and RH (rice husk). For these three wastes, the fit of the model to the experimental data has an average root-mean-square deviation of 9%. The time-lag model leads to the formulation of two measures or indexes of biodegradability of a particular waste. The values of these indexes are much higher for FVW compared to those for OFMSW and RH showing that the susceptibility of FVW to anaerobic digestion far exceeds that of the other two wastes.
Thermodiffusion of polycyclic aromatic hydrocarbons in binary mixtures
Authors: Hashmi Sara M. , Senthilnathan Sid , Firoozabadi Abbas
Published: November 2016

Thermodiffusion in liquid mixtures may explain some counter-intuitive but naturally occurring phenomena such as hydrocarbon reservoirs with heavier component(s) stratified on top of lighter ones. However, beyond benchmark systems, systematic measurements of thermodiffusion in binary organic mixtures are lacking. We use an optical beam deflection apparatus to simultaneously probe Fickian and thermal diffusion in binary solution mixtures of polycyclic aromatic hydrocarbons dissolved in alkanes, and measure both Fickian diffusion D and the Soret coefficient ST, and then obtain the thermodiffusion coefficient DT. In a series of nine binary mixtures, we vary both the size of the aromatic compound from two to four rings, as well as the length of the alkane chain from 6 to 16 carbons. To probe the effect of increasing ring size, we include a 6-ringed aromatic compound, coronene, and toluene as a solvent, due to the insolubility of coronene in alkanes. Our results suggest that Fickian diffusion increases with the inverse of solvent viscosity and also with decreasing molecular weight of the solute. While both of these trends match our intuition, the behavior of ST and DT is more complicated. We find that ST and DT increase with the solute molecular weight when the solvent is held fixed and that the impact of solute ring size is higher in shorter chain alkane solvents.
Manipulation of the coherent spatial and angular shifts of Goos-Hänchen effect to realize the digital optical switch in silicon-on-insulator waveguide corner
Authors: Sun DeGui
Published: November 2016

In this work, based on the quantum process of the Goos-Hänchen (GH) spatial shift, a quantum process of the GH angular shift is also theoretically investigated. Then, the coherence between spatial and angular shifts in the GH effect is discovered and developed to manipulate the final total displacement for a digital optical switch. It is found that a waveguide corner structure always makes the reflected guide-mode have a GH angular shift in the minus direction when the incident beam is in the Brewster angle vicinity, while it always makes the spatial shift in the plus direction. Meanwhile, the coherence of these two GH shifts has an interesting distribution with the incident angle, and only in the common linear response area to the incident angle, the two GH shifts are mutually enhancing, and then a mini refractive index modulation of the guided-mode at the reflecting interface can create a great stable jump of reflected beam displacement at an eigenstate under the GH effect. As a result, on the 220 nm CMOS-compatible silicon-on-insulator waveguide platform, with a tapered multimode interference (MMI) waveguide, a 5 × 1018cm−3 concentration variation of free carriers can create an absolute digital total displacement of 8–25 μm of the reflected beam on the MMI waveguide output end, leading to a 1 × 5 scale digital optical switching function.
Numerical studies on the dynamics of two-layer Rayleigh-Bénard convection with an infinite Prandtl number and large viscosity contrasts
Authors: Yoshida Masaki , Hamano Yozo
Published: November 2016

The fundamental physics and dynamics relating to two-layer convection with an infinite Prandtl number and large viscosity contrasts have not yet been quantitatively resolved by previous numerical analyses or simulations and laboratory experiments. Here, a series of high-resolution numerical simulations of Rayleigh-Bénard convection with a highly viscous outer layer (HVL) and a low-viscosity inner layer (LVL) in 2-D spherical-shell geometry were performed to investigate the dynamics of convection between the two layers with large viscosity contrasts of up to 103. To achieve a two-layer thermal convection system considering a thermally and mechanically continuous interface between the two layers without any specified boundary conditions, an “effective thermal expansion coefficient” was introduced to the buoyancy term of the momentum equation, discretized in a finite-volume-based regular grid system. In this study, the heat transport efficiency of two-layer convection was evaluated, and the coupling modes between the two layers were directly analyzed using the temperature anomaly and deviatoric stress fields near the interface. Results show that the mechanical coupling mode is dominant in two-layer convection when the absolute viscosity contrast between the two layers is sufficiently small, and it weakens, becoming closer to the thermal coupling mode, as the LVL viscosity decreases. This transition from the mechanical coupling to the thermal coupling modes is quantitatively detected even when the viscosity contrast between the two layers is 10−3, and results in the stabilizing of the convection speed and the heat transport efficiency of the HVL. Applying the mantle–outer core coupling of the present Earth with an extremely large absolute viscosity contrast, our numerical results imply that thermal convection in the mantle may control the heat transport efficiency of a layered whole solid-earth system and the convective style in the outer core.
Effects of acid and metal salt additives on product characteristics of biomass microwave pyrolysis
Authors: Li Pan , Yang Haiping , Wang Xianhua , Gong Weiting , Shao Jingai , Yang Qing , Chen Hanping
Published: November 2016

To study the influence of additives on the pyrolysis behavior of microwave-heated biomass, cotton stalk pyrolysis was performed using both a particular microwave pyrolysis reactor and an electric heating system with the addition of acid (H3PO4) and metal salts (NaCl, K2CO3, and MgCl2) at 550 °C. The derived products were evaluated by environmental scanning electron microscopy, gas chromatography with mass spectrometric detection, and temperature adsorption analysis. The results indicated that microwave heating with additives was beneficial to enhance the quality of the pyrolysis products. The addition of H3PO4 was favorable for liquid oil formation with higher furfural and acetic acid contents. The highest yield of oil was achieved with 8% H3PO4, while the maximum char yield and surface area were obtained at 12% H3PO4, as higher percentages caused the formation of more porous solid char. The addition of metal salts promoted the formation of char at the cost of decreasing the liquid oil production. The maximum yields of bio-oil and char were achieved with the addition of MgCl2, while the minimum yields were obtained by adding K2CO3. The addition of MgCl2 (8%) promoted the formation and pore growth of char during the pyrolysis process; moreover, it was helpful for the production of furfural and acetic acid substances as well as a small amount of naphthalene. The addition of K2CO3 (8%) increased the gas production significantly but decreased the specific surface area of char. The addition of NaCl (8%) increased the char yield but decreased the oil and gas yields slightly. The comparative results showed that microwave pyrolysis with H3PO4 and MgCl2 additives were beneficial for the preparation of activated char with a large specific surface area and optimal formation of bio-oil.
Silicon-wall interfacial free energy via thermodynamics integration
Authors: Shou Wan , Pan Heng
Published: November 2016

We compute the interfacial free energy of a silicon system in contact with flat and structured walls by molecular dynamics simulation. The thermodynamics integration method, previously applied to Lennard-Jones potentials [R. Benjamin and J. Horbach, J. Chem. Phys. 137, 044707 (2012)], has been extended and implemented in Tersoff potentials with two-body and three-body interactions taken into consideration. The thermodynamic integration scheme includes two steps. In the first step, the bulk Tersoff system is reversibly transformed to a state where it interacts with a structureless flat wall, and in a second step, the flat structureless wall is reversibly transformed into an atomistic SiO2 wall. Interfacial energies for liquid silicon-wall interfaces and crystal silicon-wall interfaces have been calculated. The calculated interfacial energies have been employed to predict the nucleation mechanisms in a slab of liquid silicon confined by two walls and compared with MD simulation results.
Circular photogalvanic effect in organometal halide perovskite CH3NH3PbI3
Authors: Li Junwen , Haney Paul M.
Published: November 2016

We study the circular photogalvanic effect in the organometal halide perovskite solar cell absorber CH3NH3PbI3. The calculated photocurrent density for a system with broken inversion symmetry is about 10−9 A/W, comparable to the previously studied quantum well and bulk Rashba systems. The circular photogalvanic effect relies on inversion symmetry breaking, so that by tuning the optical penetration depth, the degree of inversion symmetry breaking can be probed at different depths from the sample surface. We propose that measurements of this effect may clarify the presence or absence of inversion symmetry, which remains a controversial issue and has been argued to play an important role in the high conversion efficiency of this material.
Excited-state intramolecular proton transfer and photoswitching in hydroxyphenyl-imidazopyridine derivatives: A theoretical study
Authors: Omidyan Reza , Iravani Maryam
Published: November 2016

The MP2/CC2 and CASSCF theoretical approaches have been employed to determine the excited state proton transfer and photophysical nature of the four organic compounds, having the main frame of hydroxyphenyl-imidzaopyridine (HPIP). The nitrogen insertion effect, in addition to amine (–NH2) substitution has been investigated extensively by following the transition energies and deactivation pathways of resulted HPIP derivatives. It has been predicted that the excited state intramolecular proton transfer with or without small barrier is the most important feature of these compounds. Also, for all of the considered HPIP derivatives, a conical intersection (CI) between ground and the S1 excited state has been predicted. The strong non-adiabatic coupling in the CI (S1/S0), drives the system back to the ground state in which the proton may either return to the phenoxy unit and thus close the photocycle, or the system can continue the twisting motion that results in formation of a γ-photochromic species. This latter species can be responsible for photochromism of HPIP derivative systems.
A novel microgripper hybrid driven by a piezoelectric stack actuator and piezoelectric cantilever actuators
Authors: Chen Weilin , Zhang Xianmin , Fatikow Sergej
Published: November 2016

For the piezo-driven microgripper, one issue is to enlarge the grasping stroke and realize parallel grasping movement in the compact design. Piezoelectric stack actuator (PSA) and piezoelectric cantilever actuator (PCA) are two kinds of typical piezoelectric actuators. In this study, a novel microgripper hybrid driven by a PSA and two PCAs is proposed, which can be a better solution for the issue, compared with the previous microgripper using PSA-driven multi-stages displacement amplification mechanism (DAM) or using longer and narrower PCAs. A compact one-stage orthogonal DAM is proposed for the PSA in the microgripper, which can enlarge the grasping stroke and realize parallel grasping movement. The proposed orthogonal DAM is a triangulation amplification-based mechanism with undetermined structural parameters. Bidirectional symmetric input forces/displacements are not required in the proposed design. The number of the undetermined parameters and the solution principle are analyzed. Finite element analysis is used to verify the proposed DAM. The gripper arms are designed as two PCAs, for which the grasping and parasitic movements of the free end are modeled. Piezoelectric-static coupling finite element analysis is used to verify the models. The PCAs-driven grasping with considerable parasitic movement can be used in the coarse positioning. The integration of the hybrid-driven microgripper is presented, and its performances are presented and verified by experiments.
Strong electrically tunable MoTe2/graphene van der Waals heterostructures for high-performance electronic and optoelectronic devices
Authors: Wang Feng , Yin Lei , Wang Zhenxing , Xu Kai , Wang Fengmei , Shifa Tofik Ahmed , Huang Yun , Wen Yao , Jiang Chao , He Jun
Published: November 2016

MoTe2 is an emerging two-dimensional layered material showing ambipolar/p-type conductivity, which makes it an important supplement to n-type two-dimensional layered material like MoS2. However, the properties based on its van der Waals heterostructures have been rarely studied. Here, taking advantage of the strong Fermi level tunability of monolayer graphene (G) and the feature of van der Waals interfaces that is free from Fermi level pinning effect, we fabricate G/MoTe2/G van der Waals heterostructures and systematically study the electronic and optoelectronic properties. We demonstrate the G/MoTe2/G FETs with low Schottky barriers for both holes (55.09 meV) and electrons (122.37 meV). Moreover, the G/MoTe2/G phototransistors show high photoresponse performances with on/off ratio, responsivity, and detectivity of ∼105, 87 A/W, and 1012 Jones, respectively. Finally, we find the response time of the phototransistors is effectively tunable and a mechanism therein is proposed to explain our observation. This work provides an alternative choice of contact for high-performance devices based on p-type and ambipolar two-dimensional layered materials.
On fixed point planar algebras
Authors: Brothier Arnaud
Published: November 2016

To a weighted graph can be associated a bipartite graph planar algebra P. We construct and study the symmetric enveloping inclusion of P. We show that this construction is equivariant with respect to the automorphism group of P. We consider subgroups G of the automorphism of P such that the G-fixed point space PG is a subfactor planar algebra. As an application we show that if G is amenable, then PG is amenable as a subfactor planar algebra. We define the notions of a cocycle action of a Hecke pair on a tracial von Neumann algebra and the corresponding crossed product. We show that a large class of symmetric enveloping inclusions of subfactor planar algebras can be described by such a crossed product.
Incorporating large-size photovoltaic units in extension plans of power grids
Authors: Shayeghi H. , Hashemi Y.
Published: November 2016

This paper proposes a model for coordinated transmission expansion planning-reactive expansion planning (TEP-RPP) that incorporates the costs related to the operation of large-scale photovoltaic units (LPU). The model is based on the dynamic evaluation of LPU generation and the effect of it on TEP-RPP problem. In a system with the presence of LPU and conventional units, the network expansion project has been dependent on two important environmental factors, solar irradiation and ambient temperature. The TEP-RPP issue has been systematized in a multi-purpose form based on investment and operation cost, voltage deviation, and stability criterion. A multi-objective gravitational search method is implemented to extract the Pareto-archive curve of the presented multi-purpose issue. Algorithm of similarity to ideal solution is used to trade-off different points of Pareto curve. The proposed mythology has been evaluated on two different modified systems, Azarbaijan regional power system of Iran and IEEE 30 bus test system. It is indicated that the presented model can be used effectively to study the intermittent impact of LPU on the solution of the TEP-RPP problem.
Concentration in vanishing pressure limit of solutions to the modified Chaplygin gas equations
Authors: Yang Hanchun , Wang Jinhuan
Published: November 2016

Two kinds of occurrence mechanism on the phenomenon of concentration and the formation of delta shock wave in vanishing pressure limit of solutions to the modified Chaplygin gas equations are analyzed and identified. The Riemann problem of the modified Chaplygin gas equations is first solved. Then it is shown that, as the pressure vanishes, any two-shock Riemann solution tends to a delta-shock solution to the transport equations, and the intermediate density between the two shocks tends to a weighted δ-measure which forms a delta shock wave; any two-rarefaction-wave Riemann solution tends to a two-contact-discontinuity solution to the transport equations, and the nonvacuum intermediate state in between tends to a vacuum state. It is also shown that, as the pressure approaches the generalized Chaplygin gas pressure, any two-shock Riemann solution tends to a delta-shock solution to the generalized Chaplygin gas equations. Some numerical results are presented to show the formation process of delta shock waves and vacuum states.
Inverse polarity of the resistive switching effect and strong inhomogeneity in nanoscale YBCO-metal contacts
Authors: Truchly M. , Plecenik T. , Zhitlukhina E. , Belogolovskii M. , Dvoranova M. , Kus P. , Plecenik A.
Published: November 2016

We have studied a bipolar resistive switching phenomenon in c-axis oriented normal-state YBa2Cu3O7-c (YBCO) thin films at room temperature by scanning spreading resistance microscopy (SSRM) and scanning tunneling microscopy (STM) techniques. The most striking experimental finding has been the opposite (in contrast to the previous room and low-temperature data for planar metal counter-electrode-YBCO bilayers) voltage-bias polarity of the switching effect in all SSRM and a number of STM measurements. We have assumed that the hysteretic phenomena in current-voltage characteristics of YBCO-based contacts can be explained by migration of oxygen-vacancy defects and, as a result, by the formation or dissolution of more or less conductive regions near the metal–YBCO interface. To support our interpretation of the macroscopic resistive switching phenomenon, a minimalist model that describes radical modifications of the oxygen-vacancy effective charge in terms of a charge-wind effect was proposed. It was shown theoretically that due to the momentum exchange between current carriers (holes in the YBCO compound) and activated oxygen ions, the direction in which oxygen vacancies are moving is defined by the balance between the direct electrostatic force on them and that caused by the current-carrier flow.
High power telecommunication-compatible photoconductive terahertz emitters based on plasmonic nano-antenna arrays
Authors: Yardimci Nezih Tolga , Lu Hong , Jarrahi Mona
Published: November 2016

We present a high-power and broadband photoconductive terahertz emitter operating at telecommunication optical wavelengths, at which compact and high-performance fiber lasers are commercially available. The presented terahertz emitter utilizes an ErAs:InGaAs substrate to achieve high resistivity and short carrier lifetime characteristics required for robust operation at telecommunication optical wavelengths. It also uses a two-dimensional array of plasmonic nano-antennas to offer significantly higher optical-to-terahertz conversion efficiencies compared to the conventional photoconductive emitters, while maintaining broad operation bandwidths. We experimentally demonstrate pulsed terahertz radiation over 0.1–5 THz frequency range with the power levels as high as 300 μW. This is the highest-reported terahertz radiation power from a photoconductive emitter operating at telecommunication optical wavelengths.
Silver free III-nitride flip chip light-emitting-diode with wall plug efficiency over 70% utilizing a GaN tunnel junction
Authors: Yonkee B. P. , Young E. C. , DenBaars S. P. , Nakamura S. , Speck J. S.
Published: November 2016

A molecular beam epitaxy regrowth technique was demonstrated on standard industrial patterned sapphire substrate light-emitting diode (LED) epitaxial wafers emitting at 455 nm to form a GaN tunnel junction. By using an HF pretreatment on the wafers before regrowth, a voltage of 3.08 V at 20 A/cm2 was achieved on small area devices. A high extraction package was developed for comparison with flip chip devices which utilize an LED floating in silicone over a BaSO4 coated header and produced a peak external quantum efficiency (EQE) of 78%. A high reflectivity mirror was designed using a seven-layer dielectric coating backed by aluminum which has a calculated angular averaged reflectivity over 98% between 400 and 500 nm. This was utilized to fabricate a flip chip LED which had a peak EQE and wall plug efficiency of 76% and 73%, respectively. This flip chip could increase light extraction over a traditional flip chip LED due to the increased reflectivity of the dielectric based mirror.
Enhanced efficiency of organic light-emitting devices with corrugated nanostructures based on soft nano-imprinting lithography
Authors: Liu Yue-Feng , An Ming-Hui , Zhang Xu-Lin , Bi Yan-Gang , Yin Da , Zhang Yi-Fan , Feng Jing , Sun Hong-Bo
Published: November 2016

An enhanced efficiency organic light-emitting device (OLED) with corrugated nanostructures on a small-molecule organic film has been demonstrated. By patterning the hole transport layer via soft nano-imprinting lithography and coating with Ag, a nanostructured cathode is introduced to enhance the light extraction of the OLED without affecting the flatness and conductivity of the indium-tin-oxide film. Both luminance and current efficiency are improved compared with those of conventional planar devices. The observable improvement in luminance and current efficiency can be ascribed to the surface plasmonic and scattering effects caused by the Ag nanostructures. Moreover, theoretical simulations also demonstrate that the power loss to surface plasmon-polariton modes has been recovered.
Investigation of the operating characteristics of a 12 stepped-cavity relativistic magnetron with axial extraction driven by an “F” transparent cathode using particle-in-cell simulations
Authors: Liu M. , Schamiloglu E. , Jiang W. , Fuks M. , Liu C.
Published: November 2016

We explore the performance of a 12 stepped-cavity relativistic magnetron with axial extraction (12 stepped-cavity RMDO) driven by an “F” transparent cathode (the “F” transparent cathode is a coaxial transparent cathode with two azimuthal periods of increased thickness and which looks like the letter “F,” so we call it “F” transparent cathode) through particle-in-cell (PIC) simulations. It is shown that using the “F” transparent cathode, an electronic efficiency of 70% with gigawatt output power is obtained while reducing the axial leakage current by about 50% compared to using the usual transparent cathode. Further PIC simulations demonstrate that frequency bifurcation occurs and mode switching can be achieved using several hundred kilowatts input RF power in the 12 stepped-cavity RMDO driven by an “F” transparent cathode. For example, it was found that using an applied driver power of 180 kW for 10 ns, the operating TE31 mode can be switched to the TE41 mode. It is also found that the secondary electron and backscattered electron emission and axial leakage current were two disturbing factors for the 12 stepped-cavity RMDO when it works at a stable operation mode but when the 12 stepped-cavity RMDO works near the critical magnetic field at the boundary between two modes, these two factors would lead to the operation modes changing.
Filtering characteristics of a graphene ribbon with a rectangle ring in infrared region
Authors: Wang Yueke , Hong Xiaorong , Yang Guofeng , Sang Tian
Published: November 2016

We propose a structure of a graphene ribbon with a rectangle ring, which is deposited on SiO2 substrate. Our simulation results, conducted by finite element method, show that the transmission dips originate from the ring resonance of the fundamental edge graphene plasmons mode. By choosing specific parameters, the transmission dips of 6th and 4th order ring resonances can split into two, respectively, due to corner effect. Thanks to tunable permittivity of graphene by gate voltages, active control of filtering window is achieved. It is believed that our findings provide a smart way to design a tunable multiple window filter at infrared region.
What grades and achievement tests measure
Authors: Borghans Lex , Golsteyn Bart H. H. , Heckman James J. , Humphries John Eric
Published: November 2016

Significance

Grades and scores on achievement tests are widely used as measures of cognition. This paper examines these measures and their constituent parts. We establish that, on average, grades and achievement tests are generally better predictors of life outcomes than “pure” measures of intelligence. The reason is that they capture aspects of personality that have been shown to be predictive in their own right. All of the standard measures of “intelligence” or “cognition” are influenced by aspects of personality, albeit to varying degrees, depending on the measure. This result has important implications for the interpretation of studies using scores on achievement tests and grades to explain differences in outcomes and for the use of standard cognitive measures to evaluate the effectiveness of public policies.
Molecular and physiological evidence of genetic assimilation to high CO2in the marine nitrogen fixerTrichodesmium
Authors: Walworth Nathan G. , Lee Michael D. , Fu Fei-Xue , Hutchins David A. , Webb Eric A.
Published: November 2016

Significance

The free-living cyanobacteriumTrichodesmiumis an important nitrogen-fixer in the global oceans, yet virtually nothing is known about its molecular evolution to increased CO2. Here we show thatTrichodesmiumcan fix a plastic, short-term response upon long-term adaptation, potentially through genetic assimilation. We provide transcriptional evidence for molecular mechanisms that parallel the fixation of the plastic phenotype, thereby demonstrating an important evolutionary capability inTrichodesmiumCO2adaptation. Transcriptional shifts involve transposition and other regulatory mechanisms (sigma factors) that control a variety of metabolic pathways, suggesting alterations in upstream regulation to be important under genetic assimilation. Together, these data highlight potential biochemical evidence of genetic assimilation in a keystone marine N2-fixer, with broad implications for microbial evolution and biogeochemistry.
Control of transcriptional pausing by biased thermal fluctuations on repetitive genomic sequences
Authors: Imashimizu Masahiko , Afek Ariel , Takahashi Hiroki , Lubkowska Lucyna , Lukatsky David B.
Published: November 2016

Significance

How does RNA polymerase (RNAP) accurately and orderly control elongation of RNA in nanosystems dominated by random thermal fluctuations? Our statistical approach challenges this open question by identifying a linkage between thermal fluctuations, repetitive DNA sequences encoded in a genome, and RNAP pausing during elongation. Until now, it has been reasonably assumed that the structure of an elongation complex (EC) at any given location along DNA ultimately controls its enzymatic function. Contrary to this assumption, we show that nonlocal thermal fluctuations of the EC on repetitive DNA sequence elements statistically and robustly affect RNAP elongation by stabilizing pausing. This study also provides a proof of concept for the significance of thermal fluctuations in a wide variety of enzymatic systems.
Tian’s properness conjectures and Finsler geometry of the space of Kähler metrics
Authors: Darvas Tamás , Rubinstein Yanir
Published: November 2016

Well-known conjectures of Tian predict that the existence of canonical Kähler metrics should be equivalent to various notions of properness of Mabuchi’s K-energy functional. First, we provide counterexamples to Tian’s first conjecture in the presence of continuous automorphisms. Second, we resolve Tian’s second conjecture, confirming the Moser–Trudinger inequality for Fano manifolds. The construction hinges upon an alternative approach to properness that uses in an essential way the metric completion with respect to a Finsler metric and its quotients with respect to group actions. This approach also allows us to formulate and prove new optimal replacements for Tian’s first conjecture in the setting of smooth and singular Kähler–Einstein metrics, with or without automorphisms, as well as for Kähler–Ricci solitons. Moreover, we reduce both Tian’s original first conjecture (in the absence of automorphisms) and our modification of it (in the presence of automorphisms) in the general case of constant scalar curvature metrics to a conjecture on regularity of minimizers of the K-energy in the Finsler metric completion.
Evaluation of a Training Program to Reduce Stressful Trunk Postures in the Nursing Professions: A Pilot Study
Authors: Kozak Agnessa , Freitag Sonja , Nienhaus Albert
Published: November 2016

Objectives:

The aim of this pilot study was to evaluate metrologically the effectiveness of a training program on the reduction of stressful trunk postures in geriatric nursing professions.

Methods:

A training program, consisting of instruction on body postures in nursing, practical ergonomic work methods at the bedside or in the bathroom, reorganization of work equipment, and physical exercises, was conducted in 12 wards of 6 nursing homes in Germany. The Computer-Assisted Recording and Long-Term Analysis of Musculoskeletal Loads (CUELA) measurement system was used to evaluate all movements and trunk postures adopted during work before and 6 months after the training program. In total, 23 shifts were measured. All measurements were supported by video recordings. A specific software program (WIDAAN 2.75) was used to synchronize the measurement data and video footage.

Results:

The median proportion of time spent in sagittal inclinations at an angle of >20° was significantly reduced (by 29%) 6 months after the intervention [from 35.4% interquartile range (27.6–43.1) to 25.3% (20.7–34.1); P < 0.001]. Very pronounced inclinations exceeding 60° [2.5% (1.1–4.6) to 1.0% (0.8–1.7); P = 0.002] and static inclinations of over 20° for >4 s [4.4% (3.0–6.7) to 3.6% (2.5–4.5); P < 0.001] were significantly reduced, by 60% and 22%, respectively. Video analysis showed that in 49% of care situations, ergonomic measures were implemented properly, either at the bedside or in the bathroom.

Conclusions:

Stressful trunk postures could be significantly reduced by raising awareness of the physical strains that frequently occur during a shift, by changes in work practices and by redesigning the work environment. Workplace interventions aimed at preventing or reducing low back pain in nursing personnel would probably benefit from sensitizing employees to their postures during work.
Effects of Pathogen Population Levels and Crop-Derived Nutrients on Development of Soybean Sudden Death Syndrome and Growth of Fusarium virguliforme
Authors: Freed Gretchen M. , Floyd Crystal M. , Malvick Dean K.
Published: November 2016

Sudden death syndrome (SDS) of soybean, caused by Fusarium virguliforme, is a significant disease of soybean. The suite of factors that influence disease development is incompletely understood. The goal of this study was to determine the effects of pathogen population levels, crop residues, seed exudates, and their interactions on development of SDS and growth of F. virguliforme. Studies were conducted in a greenhouse with cultivars susceptible and partially resistant to SDS, four pathogen population levels, and six crop residue treatments (none; ground corn seed, stalks, and roots; ground soybean stems; and sorghum seed). Root rot was assessed 15 and 50 days after inoculation (dai) and foliar disease and plant biomass were assessed 50 dai. Population level increases and crop residues had significant interacting effects on increasing foliar disease severity and root rot and on biomass reduction. Disease severity was positively correlated with population and biomass was negatively correlated. Plants grown with no crop residues exhibited low or no root rot or foliar disease 15 dai, and severity was greatest with corn and sorghum seed. In vitro studies were conducted to test the effects of exudates collected from germinating soybean and corn seed on growth of F. virguliforme and F. solani. Growth of these fungi was greater in exudates than in water. More growth occurred in exudates collected during soybean radicle emergence than those sampled at other times during germination. These studies show that pathogen population levels and crop-derived nutrients in soil interact and influence severity of SDS. Results have implications for gaging disease risk and managing SDS.
Biological and Molecular Properties of aTurnip mosaic virus(TuMV) Strain that Breaks TuMV Resistances inBrassica napus
Authors: Guerret Marine G. L. , Nyalugwe Eviness P. , Maina Solomon , Barbetti Martin J. , van Leur Joop A. G. , Jones Roger A. C.
Published: November 2016

A new resistance-breaking strain of Turnip mosaic virus (TuMV) overcomes TuMV resistance genes that currently suppress spread of this virus in Brassica napus crops in the Liverpool Plains region of eastern Australia. Isolates 12.1 and 12.5 of this strain and three other isolates in TuMV pathotypes 1 (NSW-2), 7 (NSW-1), and 8 (WA-Ap1) were inoculated to plants of 19 B. napus cultivars and one breeding line. All plants of these cultivars and the breeding line proved susceptible to 12.1 and 12.5 but developed only resistance phenotypes with WA-Ap1 or mostly resistance phenotypes with NSW-1 and NSW-2. Five different TuMV resistance phenotypes occurred either alone or segregating in different combinations. When these five isolates were inoculated to plants of nine other crop or wild Brassicaceae spp. and four indicator hosts in other families, 12.1 and 12.5 resembled the other three in inducing TuMV resistance phenotypes in some Brassicaceae spp. but not others, and by inducing extreme resistance phenotypes in all inoculated plants of B. oleracea var. botrytis and Raphanus sativus. Therefore, the overall resistance-breaking properties of 12.1 and 12.5 were restricted to B. napus. When isolates 12.1, 12.5, and WA-Ap1 and additional Australian isolate WA-EP1 were sequenced and complete genomes of each compared, 12.1 and 12.5 grouped separately from the other 2 and from all 23 Australian isolates with complete genomes sequenced previously. In addition, there was evidence for at least six separate TuMV introductions to Australia. Spread of this B. napus resistance-breaking strain poses a significant threat to the B. napus oilseed industry. Breeding B. napus cultivars with resistance to this strain constitutes a critical priority for B. napus breeding programs in Australia and elsewhere.
Effect of Inoculum Concentration and Interrupted Wetness Duration on the Development of Anthracnose Fruit Rot of Strawberry
Authors: Forcelini Bruna B. , Gonçalves Fabricio Packer , Peres Natalia A.
Published: November 2016

Anthracnose fruit rot (AFR) of strawberry, caused by Colletotrichum acutatum, greatly affects production if not controlled. Application of fungicides in addition to the use of less susceptible cultivars are important tools for AFR control. The effects of interrupted wetness duration and inoculum concentration on the development of AFR were evaluated on strawberry cultivars with different levels of susceptibility. Fruit rot and flower blight incidence generally increased with increasing inoculum concentration. ‘Camarosa’ and ‘Treasure’ were more susceptible than ‘Strawberry Festival’ and flowers were more susceptible than immature fruit for most cultivars. Interruption in wetness periods had a significant effect on disease incidence when fruit where exposed to dry periods of 6 h or more compared with 24 h of continuous wetness. The results of this study will be used to refine a disease-warning system to predict AFR outbreaks in Florida strawberry production fields.
Donor-site Morbidity of Medial and Lateral Thigh-based Flaps: A Comparative Study
Authors: Purnell Chad A. , Lewis Kevin C. , Mioton Lauren M. , Hanwright Philip J. , Galiano Robert D. , Dumanian Gregory A. , Alghoul Mohammed S.
Published: November 2016

Background:

Free and pedicled medial and lateral thigh-based flaps are common reconstructive procedures. However, there have been no comparative studies of morbidity between medial and lateral donor sites.

Methods:

We conducted an Enterprise Data Warehouse-based review of all the senior authors’ (R.D.G., G.A.D., and M.S.A.) thigh-based free and pedicled flaps. Patient demographic data, donor-site complications, drain duration, and number of postoperative visits were collected and compared. Complications were also compared between fasciocutaneous flaps and muscle or myocutaneous flaps, and skin grafted donor sites.

Results:

We analyzed 352 flap donor sites, with 155 medial and 197 lateral. Two hundred seventeen (217) flaps were pedicled. Flap types included 127 gracilis, 27 rectus femoris, 134 anterolateral thigh, and 36 vastus lateralis-only flaps. There were no significant differences in complications between medial (17.4%) and lateral thigh (21.3%) donor sites, although lateral thigh flaps had a mean of 1 additional postoperative visit. Rates of wound dehiscence/healing issues were significantly higher in both gracilis myocutaneous flaps (25.9%) and flaps requiring a skin grafted donor site (31.2%). Postoperative therapeutic anticoagulation was the only significant risk factor for a donor-site complication. Flap complications resulted in increased drain duration and postoperative office visits.

Conclusions:

Donor-site morbidity is similar in both lateral and medial thigh-based flaps. The inclusion of muscle in the flap from either donor site does not seem to increase complications, but the inclusion of a skin paddle with gracilis muscle, or a skin grafted lateral thigh donor site, results in increased wound healing complications.