bluuebunny/crossref_metadata_2025 huggingface dataset:
E-Leadership through Strategic Alignment: An Empirical Study of Small- and Medium-sized Enterprises in the Digital Age
Authors: Li Weizi , Liu Kecheng , Belitski Maksim , Ghobadian Abby , O'Regan Nicholas
Published: June 2016

Small- and medium-sized enterprises (SMEs) play an important role in the European economy. A critical challenge faced by SME leaders, as a consequence of the continuing digital technology revolution, is how to optimally align business strategy with digital technology to fully leverage the potential offered by these technologies in pursuit of longevity and growth. There is a paucity of empirical research examining how e-leadership in SMEs drives successful alignment between business strategy and digital technology fostering longevity and growth. To address this gap, in this paper we develop an empirically derived e-leadership model. Initially we develop a theoretical model of e-leadership drawing on strategic alignment theory. This provides a theoretical foundation on how SMEs can harness digital technology in support of their business strategy enabling sustainable growth. An in-depth empirical study was undertaken interviewing 42 successful European SME leaders to validate, advance and substantiate our theoretically driven model. The outcome of the two stage process – inductive development of a theoretically driven e-leadership model and deductive advancement to develop a complete model through in-depth interviews with successful European SME leaders – is an e-leadership model with specific constructs fostering effective strategic alignment. The resulting diagnostic model enables SME decision makers to exercise effective e-leadership by creating productive alignment between business strategy and digital technology improving longevity and growth prospects.
Low-frequency dynamics of aqueous alkali chloride solutions as probed by terahertz spectroscopy
Authors: Kann Z. R. , Skinner J. L.
Published: June 2016

Terahertz (far infrared) spectroscopy provides a useful tool for probing both ionic motions in solution and the effect of ionic solutes on the dynamics of the solvent. In this study, we calculate terahertz spectra of aqueous alkali chloride solutions using classical but novel (the water model includes three-body interactions, the ion parameterization is non-standard, and the dipole surface is polarizable) molecular dynamics simulations. The calculated spectra compare reasonably well to experimental spectra. Decomposition of the calculated spectra is used to gain a deeper understanding of the physical phenomena underlying the spectra and the connection to, for instance, the vibrational density of states for the ions. The decomposed results are also used to explain many of the cation-dependent trends observed in the experimental spectra.
Design and calibration of a novel transient radiative heat flux meter for a spacecraft thermal test
Authors: Sheng Chunchen , Hu Peng , Cheng Xiaofang
Published: June 2016

Radiative heat flux measurement is significantly important for a spacecraft thermal test. To satisfy the requirements of both high accuracy and fast response, a novel transient radiative heat flux meter was developed. Its thermal receiver consists of a central thermal receiver and two thermal guarded annular plates, which ensure the temperature distribution of the central thermal receiver to be uniform enough for reasonably applying lumped heat capacity method in a transient radiative heat flux measurement. This novel transient radiative heat flux meter design can also take accurate measurements regardless of spacecraft surface temperature and incident radiation spectrum. The measurement principle was elaborated and the coefficients were calibrated. Experimental results from testing a blackbody furnace and an Xenon lamp show that this novel transient radiative heat flux meter can be used to measure transient radiative heat flux up to 1400 W/m2 with high accuracy and the response time of less than 10 s.
Initial mechanisms for the unimolecular decomposition of electronically excited nitrogen-rich energetic materials with tetrazole rings: 1-DTE, 5-DTE, BTA, and BTH
Authors: Yuan Bing , Bernstein Elliot R.
Published: June 2016

Unimolecular decomposition of nitrogen-rich energetic molecules 1,2-bis(1H-tetrazol-1-yl)ethane (1-DTE), 1,2-bis(1H-tetrazol-5-yl)ethane (5-DET), N,N-bis(1H-tetrazol-5-yl)amine (BTA), and 5,5’-bis(tetrazolyl)hydrazine (BTH) has been explored via 283 nm two photon laser excitation. The maximum absorption wavelength in the UV-vis spectra of all four materials is around 186–222 nm. The N2 molecule, with a cold rotational temperature (<30 K), is observed as an initial decomposition product from the four molecules, subsequent to UV excitation. Initial decomposition mechanisms for these four electronically excited isolated molecules are explored at the complete active space self-consistent field (CASSCF) level. Potential energy surface calculations at the CASSCF(12,8)/6-31G(d) level illustrate that conical intersections play an essential role in the decomposition mechanism. The tetrazole ring opens on the S1 excited state and through conical intersections (S1/S0)CI, N2 product is formed on the ground state potential energy surface without rotational excitation. The tetrazole rings of all four energetic molecules open at the N1—N2 ring bond with the lowest energy barrier: the C—N bond opening has higher energy barrier than that for any of the N—N ring bonds. Therefore, the tetrazole rings open at their N—N bonds to release N2. The vibrational temperatures of N2 product from all four energetic materials are hot based on theoretical calculations. The different groups (CH2—CH2, NH—NH, and NH) joining the tetrazole rings can cause apparent differences in explosive behavior of 1-DTE, 5-DTE, BTA, and BTH. Conical intersections, non-Born-Oppenheimer interactions, and dynamics are the key features for excited electronic state chemistry of organic molecules, in general, and energetic molecules, in particular.
Corresponding-states behavior of an ionic model fluid with variable dispersion interactions
Authors: Weiss Volker C.
Published: June 2016

Guggenheim’s corresponding-states approach for simple fluids leads to a remarkably universal representation of their thermophysical properties. For more complex fluids, such as polar or ionic ones, deviations from this type of behavior are to be expected, thereby supplying us with valuable information about the thermodynamic consequences of the interaction details in fluids. Here, the gradual transition of a simple fluid to an ionic one is studied by varying the relative strength of the dispersion interactions compared to the electrostatic interactions among the charged particles. In addition to the effects on the reduced surface tension that were reported earlier [F. Leroy and V. C. Weiss, J. Chem. Phys. 134, 094703 (2011)], we address the shape of the coexistence curve and focus on properties that are related to and derived from the vapor pressure. These quantities include the enthalpy and entropy of vaporization, the boiling point, and the critical compressibility factor Zc. For all of these properties, the crossover from simple to characteristically ionic fluid is seen once the dispersive attraction drops below 20%–40% of the electrostatic attraction (as measured for two particles at contact). Below this threshold, ionic fluids display characteristically low values of Zc as well as large Guggenheim and Guldberg ratios for the reduced enthalpy of vaporization and the reduced boiling point, respectively. The coexistence curves are wider and more skewed than those for simple fluids. The results for the ionic model fluid with variable dispersion interactions improve our understanding of the behavior of real ionic fluids, such as inorganic molten salts and room temperature ionic liquids, by gauging the importance of different types of interactions for thermodynamic properties.
New ultrarapid-scanning interferometer for FT-IR spectroscopy with microsecond time-resolution
Authors: Süss B. , Ringleb F. , Heberle J.
Published: June 2016

A novel Fourier-transform infrared (FT-IR) rapid-scan spectrometer has been developed (patent pending EP14194520.4) which yields 1000 times higher time resolution as compared to conventional rapid-scanning spectrometers. The central element to achieve faster scanning rates is based on a sonotrode whose front face represents the movable mirror of the interferometer. A prototype spectrometer with a time resolution of 13 μs was realized, capable of fully automated long-term measurements with a flow cell for liquid samples, here a photosynthetic membrane protein in solution. The performance of this novel spectrometer is demonstrated by recording the photoreaction of bacteriorhodopsin initiated by a short laser pulse that is synchronized to the data recording. The resulting data are critically compared to those obtained by step-scan spectroscopy and demonstrate the relevance of performing experiments on proteins in solution. The spectrometer allows for future investigations of fast, non-repetitive processes, whose investigation is challenging to step-scan FT-IR spectroscopy.
An atomic orbital based real-time time-dependent density functional theory for computing electronic circular dichroism band spectra
Authors: Goings Joshua J. , Li Xiaosong
Published: June 2016

One of the challenges of interpreting electronic circular dichroism (ECD) band spectra is that different states may have different rotatory strength signs, determined by their absolute configuration. If the states are closely spaced and opposite in sign, observed transitions may be washed out by nearby states, unlike absorption spectra where transitions are always positive additive. To accurately compute ECD bands, it is necessary to compute a large number of excited states, which may be prohibitively costly if one uses the linear-response time-dependent density functional theory (TDDFT) framework. Here we implement a real-time, atomic-orbital based TDDFT method for computing the entire ECD spectrum simultaneously. The method is advantageous for large systems with a high density of states. In contrast to previous implementations based on real-space grids, the method is variational, independent of nuclear orientation, and does not rely on pseudopotential approximations, making it suitable for computation of chiroptical properties well into the X-ray regime.
Estimation of viscoelastic parameters in Prony series from shear wave propagation
Authors: Jung Jae-Wook , Hong Jung-Wuk , Lee Hyoung-Ki , Choi Kiwan
Published: June 2016

When acquiring accurate ultrasonic images, we must precisely estimate the mechanical properties of the soft tissue. This study investigates and estimates the viscoelastic properties of the tissue by analyzing shear waves generated through an acoustic radiation force. The shear waves are sourced from a localized pushing force acting for a certain duration, and the generated waves travel horizontally. The wave velocities depend on the mechanical properties of the tissue such as the shear modulus and viscoelastic properties; therefore, we can inversely calculate the properties of the tissue through parametric studies.
Labyrinthine water flow across multilayer graphene-based membranes: Molecular dynamics versus continuum predictions
Authors: Yoshida Hiroaki , Bocquet Lydéric
Published: June 2016

In this paper, we investigate the hydrodynamic permeance of water through graphene-based membranes, inspired by recent experimental findings on graphene-oxide membranes. We consider the flow across multiple graphene layers having nanoslits in a staggered alignment, with an inter-layer distance ranging from sub-nanometer to a few nanometers. We compare results for the permeability obtained by means of molecular dynamics simulations to continuum predictions obtained by using the lattice Boltzmann calculations and hydrodynamic modelization. This highlights that, in spite of extreme confinement, the permeability across the graphene-based membrane is quantitatively predicted on the basis of a continuum expression, taking properly into account entrance and slippage effects of the confined water flow. Our predictions refute the breakdown of hydrodynamics at small scales in these membrane systems. They constitute a benchmark to which we compare published experimental data.
Self-diffusion of protons in H2O ice VII at high pressures: Anomaly around 10 GPa
Authors: Noguchi Naoki , Okuchi Takuo
Published: June 2016

The self-diffusion of ice VII in the pressure range of 5.5–17 GPa and temperature range of 400–425 K was studied using micro Raman spectroscopy and a diamond anvil cell. The diffusion was monitored by observing the distribution of isotope tracers: D2O and H218O. The diffusion coefficient of hydrogen reached a maximum value around 10 GPa. It was two orders of magnitude greater at 10 GPa than at 6 GPa. Hydrogen diffusion was much faster than oxygen diffusion, which indicates that protonic diffusion is the dominant mechanism for the diffusion of hydrogen in ice VII. This mechanism is in remarkable contrast to the self-diffusion in ice Ih that is dominated by an interstitial mechanism for the whole water molecule. An anomaly around 10 GPa in ice VII indicates that the rate-determining process for the proton diffusion changes from the diffusion of ionic defects to the diffusion of rotational defects, which was suggested by proton conductivity measurements and molecular dynamics simulations.
Intrinsic oscillation of coupled domain walls in a perpendicularly magnetized nanowire system
Authors: Luo Xin , Lu Zhihong , Yuan Cheng , Guo Fang , Xiong Rui , Shi Jing
Published: June 2016

The dynamics of two domain walls (DWs) in a system of two nanowires with perpendicular magnetocrystalline anisotropy (PMA) was investigated by micromagnetic simulation. It was found that without applied current, the motion mode of DWs is translational motion plus oscillation. Different from its in-plane counterpart, in a two-PMA-nanowire system, the oscillation of DWs before encountering is quite intrinsic—the frequency and the amplitude only depend on the separation between nanowires and the material of the nanowires, and have no relationship with applied current and the distance between two DWs. When applying proper currents, the coupled DWs will only oscillate without performing translational motion. The oscillation frequency can reach several GHz. Besides being tuned in a large range by varying the nanowire separation, the oscillation frequency can also be slightly modified by adjusting the magnetic anisotropy (K) or magnetization (Ms) of the nanowire. This finding may be of great importance for the design of microwave oscillator with stable and accurate frequency.
Site-mixing effect on the XMCD spectrum in double perovskite Bi2FeMnO6
Authors: Ahmed Towfiq , Chen Aiping , McFarland Brian , Wang Qiang , Ohldag Hendrik , Sandberg Richard , Jia Quanxi , Yarotski Dmitry A. , Zhu Jian-Xin
Published: June 2016

We investigate magnetization in double perovskite multiferroic Bi2FeMnO6 (BFMO) thin film using density functional theory (DFT) simulations, and X-ray magnetic circular dichroism (XMCD) measurements. The exchange interaction between Fe and Mn sites gives rise to a ferrimagnetic ordering in BFMO. When grown without structural defects, distinct XMCD signal is expected from this system. The site resolved magnetization, thus, can be extracted using XMCD sum rules. Although our theoretical calculations are consistent with this expectation for the ideal BFMO system, experimental measurements find evidence of anomalous peak for the L2 and L3 edges of XMCD signals, and thus, the XMCD sum rules are no longer valid. We theoretically explain this phenomenon by considering both tetragonal (near interface), and monoclinic (bulk) phases of BFMO system, with Fe and Mn ions interchanged between their respective sites. Such site-mixing between magnetic cations are commonly found during the synthesis process. Our DFT calculations of XMCD for site interchanged Fe and Mn ions in the bulk phase (monoclinic) of BFMO are in good agreement with experimental XMCD signal and reproduce the anomalous peak features at L2/L3 edges.
Identification and mitigation of T-S waves using localized dynamic surface modification
Authors: Amitay Michael , Tuna Burak A. , Dell’Orso Haley
Published: June 2016

The control of transition from a laminar to a turbulent flow over a flat plate using localized dynamic surface modifications was explored experimentally in Rensselaer Polytechnic Institute’s subsonic wind tunnel. Dynamic surface modification, via a pair of Piezoelectrically Driven Oscillating Surface (PDOS) actuators, was used to excite and control the T-S wave over a flat plate. Creating an upstream, localized small disturbance at the most amplified frequency of fact = 250 Hz led to phase-locking the T-S wave. This enabled observation of the excited T-S wave using phase-locked stereoscopic particle image velocimetry. The growth of the T-S wave as it moved downstream was also measured using this technique (25% growth over four wavelengths of the excited wave). Activation of a downstream PDOS actuator (in addition to the upstream PDOS) at the appropriate amplitude and phase shift resulted in attenuation of the peak amplitude of the coherent velocity fluctuations (by up to 68%) and a substantial reduction of the degree of coherence of the T-S wave. Since the PDOS actuators used in this work were localized, the effect of the control strategy was confined to the region directly downstream of the PDOS actuator.
Plasmon generation in sputtered Ga-doped MgZnO thin films for solar cell applications
Authors: Awasthi Vishnu , Pandey Sushil Kumar , Garg Vivek , Sengar Brajendra S. , Sharma Pankaj , Kumar Shailendra , Mukherjee C. , Mukherjee Shaibal
Published: June 2016

The crystalline, electrical, morphological, optical properties and plasmonic behaviour of Ga doped MgZnO (GMZO) thin films grown at different substrate temperatures (200–600 °C) by a dual ion beam sputtering (DIBS) system are investigated. Transmittance value of more than ∼94% in 400–1000 nm region is observed for all GMZO films. The particle plasmon features can be detected in the absorption coefficient spectra of GMZO grown at 500 and 600 °C in the form of a peak at ∼4.37 eV, which corresponds to a plasmon resonance peak of nanoclusters formed in GMZO. The presence of such plasmonic features is confirmed by ultraviolet photoelectron spectroscopy measurements. The values of particle plasmon resonance energy of various nanoclusters are in the range of solar spectrum, and these can easily be tuned and excited at the desirable wavelengths while optimizing the efficiency of solar cells (SCs) by simple alteration of DIBS growth temperature. These nanoclusters are extremely promising to enhance the optical scattering and trapping of the incident light, which increases the optical path length in the absorber layer of cost-effective SCs and eventually increases its efficiency.
Influence of humidity on the characteristics of positive corona discharge in air
Authors: Xu Pengfei , Zhang Bo , Chen Shuiming , He Jinliang
Published: June 2016

Detailed positive corona discharge characteristics, such as the corona onset voltage, pulse amplitude, repetition frequency, average corona current, rise time, and half-wave time, are systematically studied under different air humidity with a single artificial defect electrode. The experimental results indicate that the pulse amplitude decreases with the increase of air humidity; meanwhile, the repetition frequency increases as the air humidity increases. This phenomenon is different from that of negative corona discharge. Therefore, to have an insight into the mechanism of humidity influence on positive corona discharge, a positive corona discharge model based on the continuity equations is utilized. The simulations present a dynamic development of positive corona discharge and, meanwhile, reveal the humidity influence on positive corona discharge.
Existence domains of electrostatic solitary structures in the solar wind plasma
Authors: Rubia R. , Singh S. V. , Lakhina G. S.
Published: June 2016

Electrostatic solitary waves and double layers are explored in a homogeneous, collisionless, and magnetized three-component plasma composed of hot protons, hot heavier ions (alpha particles, He++), and suprathermal electrons with kappa distribution. The Sagdeev pseudopotential technique is used to study the arbitrary amplitude ion-acoustic solitons and double layers. The effect of various parameters such as the number density of ions, ni0; the spectral index, κ; the Mach numbers, M; and the temperature ratio of ion to the electron σi on the evolution of ion-acoustic solitary waves as well as their existence domains is studied. The transition in the existence domain for slow-ion acoustic solitons from negative solitons/double layers to positive solitons/double layers is found to occur with a variation of the heavier ion temperature. It is observed that the width of the negative potential solitons increases as the amplitude increases, whereas for the positive potential solitons, the width decreases as the amplitude increases. Furthermore, it is found that the limitation on the attainable amplitudes of fast ion-acoustic solitons is attributed to that the number density of protons should remain real valued, while for the slow ion-acoustic solitons, the upper limit is provided by the requirement that the number density of heavier ions should remain real. In the presence of a double layer, the occurrence of the double layer limits the attainable amplitudes of the slow ion-acoustic solitons. The proposed plasma model is relevant to the coherent electrostatic structures observed in the solar wind at 1 AU.
Critical heat flux maxima resulting from the controlled morphology of nanoporous hydrophilic surface layers
Authors: Tetreault-Friend Melanie , Azizian Reza , Bucci Matteo , McKrell Thomas , Buongiorno Jacopo , Rubner Michael , Cohen Robert
Published: June 2016

Porous hydrophilic surfaces have been shown to enhance the critical heat flux (CHF) in boiling heat transfer. In this work, the separate effects of pore size and porous layer thickness on the CHF of saturated water at atmospheric pressure were experimentally investigated using carefully engineered surfaces. It was shown that, for a fixed pore diameter (∼20 nm), there is an optimum layer thickness (∼2 μm), for which the CHF value is maximum, corresponding to ∼115% enhancement over the value for uncoated surfaces. Similarly, a maximum CHF value (∼100% above the uncoated surface CHF) was observed while changing the pore size at a constant layer thickness (∼1 μm). To explain these CHF maxima, we propose a mechanistic model that can capture the effect of pore size and pore thickness on CHF. The good agreement found between the model and experimental data supports the hypothesis that CHF is governed by the competition between capillary wicking, viscous pressure drop and evaporation, as well as conduction heat transfer within the porous layer. The model can be used to guide the development of engineered surfaces with superior boiling performance.
Label-free measurements on cell apoptosis using a terahertz metamaterial-based biosensor
Authors: Zhang Caihong , Liang Lanju , Ding Liang , Jin Biaobing , Hou Yayi , Li Chun , Jiang Ling , Liu Weiwei , Hu Wei , Lu Yanqing , Kang Lin , Xu Weiwei , Chen Jian , Wu Peiheng
Published: June 2016

Label-free, real-time, and in-situ measurement on cell apoptosis is highly desirable in cell biology. We propose here a design of terahertz (THz) metamaterial-based biosensor for meeting this requirement. This metamaterial consists of a planar array of five concentric subwavelength gold ring resonators on a 10 μm-thick polyimide substrate, which can sense the change of dielectric environment above the metamaterial. We employ this sensor to an oral cancer cell (SCC4) with and without cisplatin, a chemotherapy drug for cancer treatment, and find a linear relation between cell apoptosis measured by Flow Cytometry and the relative change of resonant frequencies of the metamaterial measured by THz time-domain spectroscopy. This implies that we can determine the cell apoptosis in a label-free manner. We believe that this metamaterial-based biosensor can be developed into a cheap, label-free, real-time, and in-situ detection tool, which is of significant impact on the study of cell biology.
Strain engineering for mechanical properties in graphene nanoribbons revisited: The warping edge effect
Authors: Jiang Jin-Wu
Published: June 2016

We investigate the strain engineering and the edge effect for mechanical properties in graphene nanoribbons. The free edges of the graphene nanoribbons are warped due to compressive edge stresses. There is a structural transformation for the free edges from the three-dimensional warping configuration to the two-dimensional planar structure at the critical strain ϵc = 0.7%, at which the applied mechanical stress is equal to the intrinsic compressive edge stress. This structural transformation leads to step-like changes in several mechanical properties studied in the present work, including the Young's modulus, the Poisson's ratio, the quality factor of nanomechanical resonators, and the phonon edge mode.
Electroluminescence from completely horizontally oriented dye molecules
Authors: Komino Takeshi , Sagara Yuta , Tanaka Hiroyuki , Oki Yuji , Nakamura Nozomi , Fujimoto Hiroshi , Adachi Chihaya
Published: June 2016

A complete horizontal molecular orientation of a linear-shaped thermally activated delayed fluorescent guest emitter 2,6-bis(4-(10Hphenoxazin-10-yl)phenyl)benzo[1,2-d:5,4-d′] bis(oxazole) (cis-BOX2) was obtained in a glassy host matrix by vapor deposition. The orientational order of cis-BOX2 depended on the combination of deposition temperature and the type of host matrix. Complete horizontal orientation was obtained when a thin film with cis-BOX2 doped in a 4,4′-bis(N-carbazolyl)-1,1′-biphenyl (CBP) host matrix was fabricated at 200 K. The ultimate orientation of guest molecules originates from not only the kinetic relaxation but also the kinetic stability of the deposited guest molecules on the film surface during film growth. Utilizing the ultimate orientation, a highly efficient organic light-emitting diode with the external quantum efficiency of 33.4 ± 2.0% was realized. The thermal stability of the horizontal orientation of cis-BOX2 was governed by the glass transition temperature (Tg) of the CBP host matrix; the horizontal orientation was stable unless the film was annealed above Tg.
Magnetoelectric control of spin currents
Authors: Gómez J. E. , Vargas J. M. , Avilés-Félix L. , Butera A.
Published: June 2016

The ability to control the spin current injection has been explored on a hybrid magnetoelectric system consisting of a (011)-cut ferroelectric lead magnesium niobate-lead titanate (PMNT) single crystal, a ferromagnetic FePt alloy, and a metallic Pt. With this PMNT/FePt/Pt structure we have been able to control the magnetic field position or the microwave excitation frequency at which the spin pumping phenomenon between FePt and Pt occurs. We demonstrate that the magnetoelectric heterostructure operating in the L-T (longitudinal magnetized-transverse polarized) mode couples the PMNT crystal to the magnetostrictive FePt/Pt bilayer, displaying a strong magnetoelectric coefficient of ∼140 Oe cm kV−1. Our results show that this mechanism can be effectively exploited as a tunable spin current intensity emitter and open the possibility to create an oscillating or a bistable switch to effectively manipulate spin currents.
Infrared study of large scale h-BN film and graphene/h-BN heterostructure
Authors: Yu Kwangnam , Kim Jiho , Lee Chul , Jang A-Rang , Shin Hyeon Suk , Kim Keun Soo , Yu Young-Jun , Choi E. J.
Published: June 2016

We synthesize a series of CVD h-BN films and perform critical infrared spectroscopic characterization. For high-temperature (HT, Temp = 1400 °C) grown h-BN thin film, only E1u-mode infrared phonon is activated demonstrating highly aligned 2D h-BN planes over large area, whereas low-temperature (LT, Temp = 1000 °C) grown film shows two phonon peaks, E1u and A2u, due to stacking of h-BN plane at tilted angle. For CVD graphene transferred on HT h-BN/SiO2/Si substrate, interband transition spectrum σ1 shifts strongly to lower energy compared with that on LT h-BN/SiO2/Si and on bare SiO2/Si substrates, revealing that the residual carrier density n in graphene is suppressed by the use of HT h-BN layer. Also, the interband transition width of σ1 defined by effective temperature is reduced from 400 K for G/SiO2/Si to 300 K for HT h-BN/SiO2/Si. The behaviors of n and effective temperature show that the HT h-BN film can decouple CVD graphene from the impurity and defect of SiO2 leading to a large scale free-standing like graphene.
Nonthermal combined ultraviolet and vacuum-ultraviolet curing process for organosilicate dielectrics
Authors: Zheng H. , Guo X. , Pei D. , Li W. , Blatz J. , Hsu K. , Benjamin D. , Lin Y.-H. , Fung H.-S. , Chen C.-C. , Nishi Y. , Shohet J. L.
Published: June 2016

Porous SiCOH films are of great interest in semiconductor fabrication due to their low-dielectric constant properties. Post-deposition treatments using ultraviolet (UV) light on organosilicate thin films are required to decompose labile pore generators (porogens) and to ensure optimum network formation to improve the electrical and mechanical properties of low-k dielectrics. The goal of this work is to choose the best vacuum-ultraviolet photon energy in conjunction with vacuum ultraviolet (VUV) photons without the need for heating the dielectric to identify those wavelengths that will have the most beneficial effect on improving the dielectric properties and minimizing damage. VUV irradiation between 8.3 and 8.9 eV was found to increase the hardness and elastic modulus of low-k dielectrics at room temperature. Combined with UV exposures of 6.2 eV, it was found that this “UV/VUV curing” process is improved compared with current UV curing. We show that UV/VUV curing can overcome drawbacks of UV curing and improve the properties of dielectrics more efficiently without the need for high-temperature heating of the dielectric.
Flexible nanomembrane photonic-crystal cavities for tensilely strained-germanium light emission
Authors: Yin Jian , Cui Xiaorui , Wang Xiaowei , Sookchoo Pornsatit , Lagally Max G. , Paiella Roberto
Published: June 2016

Flexible photonic-crystal cavities in the form of Si-column arrays embedded in polymeric films are developed on Ge nanomembranes using direct membrane assembly. The resulting devices can sustain large biaxial tensile strain under mechanical stress, as a way to enhance the Ge radiative efficiency. Pronounced emission peaks associated with photonic-crystal cavity resonances are observed in photoluminescence measurements. These results show that ultrathin nanomembrane active layers can be effectively coupled to an optical cavity, while still preserving their mechanical flexibility. Thus, they are promising for the development of strain-enabled Ge lasers, and more generally uniquely flexible optoelectronic devices.
AC electrified jets in a flow-focusing device: Jet length scaling
Authors: Castro-Hernández Elena , García-Sánchez Pablo , Alzaga-Gimeno Javier , Tan Say Hwa , Baret Jean-Christophe , Ramos Antonio
Published: June 2016

We use a microfluidic flow-focusing device with integrated electrodes for controlling the production of water-in-oil drops. In a previous work, we reported that very long jets can be formed upon application of AC fields. We now study in detail the appearance of the long jets as a function of the electrical parameters, i.e., water conductivity, signal frequency, and voltage amplitude. For intermediate frequencies, we find a threshold voltage above which the jet length rapidly increases. Interestingly, this abrupt transition vanishes for high frequencies of the signal and the jet length grows smoothly with voltage. For frequencies below a threshold value, we previously reported a transition from a well-behaved uniform jet to highly unstable liquid structures in which axisymmetry is lost rather abruptly. These liquid filaments eventually break into droplets of different sizes. In this work, we characterize this transition with a diagram as a function of voltage and liquid conductivity. The electrical response of the long jets was studied via a distributed element circuit model. The model allows us to estimate the electric potential at the tip of the jet revealing that, for any combination of the electrical parameters, the breakup of the jet occurs at a critical value of this potential. We show that this voltage is around 550 V for our device geometry and choice of flow rates.
Undulate microarray fabrication on polymer film using standing surface acoustic waves and ultraviolet polymerization
Authors: Mei Deqing , Xue Dai , Wang Yancheng , Chen Shaochen
Published: June 2016

By exciting standing surface acoustic waves (SAWs), a monomer solution can be shaped into a wavy structure. By applying ultraviolet (UV) polymerization, a linear undulate microarray can be fabricated on the polymer material using one-dimensional standing SAWs. When two-dimensional standing SAWs are applied, a latticed microarray, which presents periodically distributed bumps and wells, can be fabricated. The periodicity of the undulate microarray is dependent on the SAW wavelength. Also, the undulating amplitude of the microarray is tunable when applying different input voltages to generate SAWs. The integrated standing SAWs and UV polymerization process provide a rapid method for creating periodic surface patterns.
Expression of selected genes related to energy mobilisation and insulin resistance in dairy cows
Authors: Fiore E. , Arfuso F. , Colitti M. , Gianesella M. , Giudice E. , Piccione G. , Morgante M.
Published: June 2016

The physiological and metabolic adaptation characterising the transition period in the dairy cows is developed by a complex modulation of different metabolic pathways as well as the expression of selected tissue-specific gene. The aim of this study was to evaluate the age effect on expression of selected genes in adipose, hepatic and muscle tissues in dairy cows during their transition period using the quantitative real-time PCR. Twenty-two pluriparous dairy cows were divided into three groups in relation to age: Group A (38 ± 2 months); Group B (52 ± 2 months) and Group C (80 ± 8 months). Lower levels of peroxisome proliferator-activated receptor gamma and higher levels of adiponectin were found in adipose tissue in Group C than Groups A and B (P < 0.05). Higher levels of solute carrier family 2/facilitated glucose transporter member 4 were found in muscle in Group C than Group A (P < 0.001) and Group B (P < 0.05). The present study showed in dairy cows that the expression of selected genes associated with mobilisation of energy and with insulin resistance are influenced by age demonstrating and highlighting the importance of a genomics approach to assess the metabolic status of dairy cows during the transition period.
Effect of marbling and chilled ageing on meat-quality traits, volatile compounds and sensory characteristics of beef longissimus dorsi muscle
Authors: Van Ba Hoa , Oliveros Cynthia M. , Park KyoungMi , Dashdorj Dashmaa , Hwang Inho
Published: June 2016

Effects of marbling and chilled ageing on technological quality traits, volatile compounds and sensory characteristics of Hanwoo beef were investigated. Three marbling groups of longissimus dorsi muscles (n = 10 each), namely, high marbling (HM), moderate marbling (MM) and slight marbling (SM), classified according to the Korean carcass-grading system, were used. Each longissimus dorsi muscle from each marbling group was divided into two equal portions, vaccum-packaged and then assigned to 1- and 7-day ageing groups. The ageing was conducted in a chilling room at 4°C. Marbling level was significantly correlated with intramuscular fat content, shear force, cooking loss, tenderness and flavour. Particularly, the HM group had a lower shear force value, and higher fat content, lightness, tenderness, flavour and overall-liking scores than did MM and SM groups. Ageing significantly reduced the shear force value and increased tenderness, flavour and overall-liking scores for the HM group. Twenty-four volatile compounds were significantly influenced by marbling and/or ageing. The SM group had the highest concentration of benzaldehyde, while HM group had the highest concentrations of octanal, nonanal and dimethyl sulfide. In conclusion, our results demonstrated that a high marbling positively affected some technological quality traits and eating quality of beef, and ageing for 7 days reduced the shear force and improved eating quality of samples in the HM group, suggesting that the highly marbled beef responds to the ageing at a faster rate.
Effects of ovariectomy on body measurements, carcass composition, and meat quality of Huainan chickens
Authors: Guo Xing , Ma Chendong , Fang Qi , Zhou Bangyuan , Wan Yi , Jiang Runshen
Published: June 2016

This study investigated the effects of ovariectomy on body measurements, carcass composition, meat quality, and steroid hormone concentrations of Huainan female chickens. The left ovaries of healthy Huainan chickens were surgically or sham removed at 7 weeks of age. Two slaughters were performed at 14 and 23 weeks of age. In each slaughter, 15 control, sham-operated, and ovariectomised chickens were used, respectively. The ovariectomised group had higher (P < 0.05) body length, keel length, body depth, and weight gain than the other two groups at 14 weeks of age. Ovariectomy increased bodyweight at 14 and 23 weeks of age. However, dressing percentage, breast muscle yield, and leg muscle yield were not affected by ovariectomy. Compared with intact and sham-operated chickens, ovariectomised chickens had higher shear force values at 23 weeks of age and higher redness values (a*) at 14 and 23 weeks of age in breast meat. Moreover, ovariectomy decreased and increased serum concentrations of oestradiol and testosterone, respectively. Therefore, ovariectomy increased bodyweight, altered breast meat quality by increasing redness values, and increased body size and growth rates during the early stage, with no effects on carcass composition yield in female chickens.
Biogenesis of sperm acrosome is regulated by pre-mRNA alternative splicing ofAcrbpin the mouse
Authors: Kanemori Yoshinori , Koga Yoshitaka , Sudo Mai , Kang Woojin , Kashiwabara Shin-ichi , Ikawa Masahito , Hasuwa Hidetoshi , Nagashima Kiyoshi , Ishikawa Yu , Ogonuki Narumi , Ogura Atsuo , Baba Tadashi
Published: June 2016

Significance

Mammalian sperm possess a Golgi-derived exocytotic organelle, the acrosome, located on the apical region of the head. Proper biogenesis of the acrosome is essential for the fertilization process because the aberrant acrosome formation results in the sterility or subfertility of males. Here, we show that the acrosome formation is governed by two forms of proacrosin-binding protein ACRBP, wild-type ACRBP-W and variant ACRBP-V5, which are generated by pre-mRNA alternative splicing ofAcrbp. ACRBP-V5 is involved in the formation and configuration of the acrosomal granule during early spermiogenesis, whereas the inactive status of proacrosin in the acrosome is maintained by ACRBP-W until acrosomal exocytosis.
B-cell–independent sialylation of IgG
Authors: Jones Mark B. , Oswald Douglas M. , Joshi Smita , Whiteheart Sidney W. , Orlando Ron , Cobb Brian A.
Published: June 2016

Significance

Sialylation of Fc domain glycans on IgG is now a recognized functional switch between pro- and anti-inflammatory antibody function. Creation and analysis of a B-cell–specific knockout of β-galactoside α-2,6-sialyltransferase 1 (ST6Gal1) revealed that IgG sialylation occurs independently of the B-cell secretory pathway and within the bloodstream after IgG secretion. This finding supports a paradigm for exogenous posttranslational modification of glycoproteins that has profound functional significance for IgG functions modulated by the conserved
N
-linked glycan within the Fc domain.
Cross-class metallo-β-lactamase inhibition by bisthiazolidines reveals multiple binding modes
Authors: Hinchliffe Philip , González Mariano M. , Mojica Maria F. , González Javier M. , Castillo Valerie , Saiz Cecilia , Kosmopoulou Magda , Tooke Catherine L. , Llarrull Leticia I. , Mahler Graciela , Bonomo Robert A. , Vila Alejandro J. , Spencer James
Published: June 2016

Significance

Bacterial diseases remain a huge burden on healthcare worldwide, with the emergence and re-emergence of strains resistant to currently used antibiotics posing an increasing clinical threat. Metallo-β-lactamases (MBLs) are key determinants of antibiotic resistance because they hydrolyze almost all β-lactam antibiotics and are unaffected by currently available β-lactamase inhibitors (βLIs). The structural diversity between MBLs has proved problematic when designing βLIs effective against all MBL targets. Here we show a series of small compounds, bisthiazolidines, which act as inhibitors of all MBL types, restoring the efficacy of currently used antibiotics against resistant bacterial strains producing different MBLs. High-resolution crystal structures reveal how diverse MBLs are inhibited by the unexpected versatility of bisthiazolidine binding, raising implications for future βLI design.
HIFI-α activation underlies a functional switch in the paradoxical role of Ezh2/PRC2 in breast cancer
Authors: Mahara Sylvia , Lee Puay Leng , Feng Min , Tergaonkar Vinay , Chng Wee Joo , Yu Qiang
Published: June 2016

Significance

The plasticity of Polycomb repressive complex 2 (PRC2) in the context of tumorigenesis has remained a subject of contention. Here we demonstrate that the equilibrium between the oncogenic and tumor-suppressive activity of PRC2 in promoting breast cancer invasion is tightly regulated by hypoxia-inducible factor 1-α. PRC2 acts as a tumor-suppressor barrier to the hypoxia-driven invasion pathway, and the impaired PRC2 activity upon hypoxia promotes a chromatin switch at proinvasion matrix metalloproteinase gene loci. The study fundamentally changed our understanding of the role of PRC2 in breast cancer and also identified a previously unidentified function of enhancer of zeste 2 to complex with Forkhead box M1 to promote cancer invasion.
Evaporation-induced stimulation of bacterial osmoregulation for electrical assessment of cell viability
Authors: Ebrahimi Aida , Alam Muhammad Ashraful
Published: June 2016

Significance

Conventional bacterial viability assays rely on cell multiplication until they are detectable by optical, electrical, or other sensors. Consequently, the assay time of classical growth-based techniques ranges from hours to weeks depending on bacteria type. In contrast, we present a fundamentally different paradigm based on bacterial osmoregulation to identify viable cells in minutes. Our label-free platform relies on two key advances: (
i
) the fact that osmoregulation is as universal as cell division and (
ii
) the ability to create a microliter-sized environment on a specially designed multifunctional structure. Our contribution advances the field with a collage of ideas from diverse disciplines (e.g., biology, microfluidics, surface energetics, and impedance spectroscopy) and therefore, will attract a broad audience of physicists, material scientists, biologists, and engineers.
Mutation of
Fnip1
is associated with B-cell deficiency, cardiomyopathy, and elevated AMPK activity
Authors: Siggs Owen M. , Stockenhuber Alexander , Deobagkar-Lele Mukta , Bull Katherine R. , Crockford Tanya L. , Kingston Bethany L. , Crawford Greg , Anzilotti Consuelo , Steeples Violetta , Ghaffari Sahar , Czibik Gabor , Bellahcene Mohamed , Watkins Hugh , Ashrafian Houman , Davies Benjamin , Woods Angela , Carling David , Yavari Arash , Beutler Bruce , Cornall Richard J.
Published: June 2016

Significance

Cellular metabolism is tightly regulated by AMP-activated protein kinase (AMPK): the function of which is influenced by folliculin (FLCN), folliculin-interacting protein (FNIP)1, and FNIP2. FLCN is a known tumor-suppressor protein that is mutated in Birt–Hogg–Dubé syndrome, whereas FNIP1 and FNIP2 are binding partners of FLCN. Previous reports have suggested that the FLCN/FNIP1/FNIP2 complex acts a positive regulator of AMPK, whereas other reports suggest the opposite. Using a new mouse model of FNIP1 deficiency, our findings support the latter: we found that mutation of
Fnip1
leads to B-cell deficiency and the development of a cardiomyopathy similar to mice and humans with gain-of-function mutations in AMPK.
Examination of Predation on Early Life Stage Delta Smelt in the San Francisco Estuary Using DNA Diet Analysis
Authors: Schreier Brian M. , Baerwald Melinda R. , Conrad J. Louise , Schumer Gregg , May Bernie
Published: June 2016

We examined predation by nonnative Mississippi Silversides Menidia audens, other small fishes, and invertebrates on the early life stages of the endangered Delta Smelt Hypomesus transpacificus, which is endemic to the Sacramento–San Joaquin Delta in California. Mississippi Silversides and other putative predators were collected primarily via boat electrofishing in the northern reaches of the upper San Francisco Estuary, an area targeted for substantial tidal wetland restoration to enhance habitat for Delta Smelt and other endangered fishes. Predators’ digestive tracts were removed and analyzed for the presence of Delta Smelt DNA by using quantitative PCR TaqMan assays. Across all sites, 69 of 550 Mississippi Silversides tested positive for Delta Smelt DNA. The number of sampled Mississippi Silversides that were positive for Delta Smelt DNA was significantly greater in offshore habitats than in nearshore habitats. Delta Smelt DNA detection data indicated that a wide variety of other species were also predators of Delta Smelt. Additionally, we used generalized linear modeling to analyze the relationship between Delta Smelt predation detections in Mississippi Silversides and concurrently collected habitat parameters. Turbidity was identified as a significant predictor of predation, as Delta Smelt DNA was detected more often in Mississippi Silverside samples from clearer water. These results suggest that restoration efforts designed to increase turbidity in the estuary may be beneficial in reducing Mississippi Silversides’ predatory impacts on Delta Smelt.

Received August 24, 2015; accepted February 3, 2016 Published online June 15, 2016
Pacific Lamprey in Coastal Drainages of California: Occupancy Patterns and Contraction of the Southern Range
Authors: Reid Stewart B. , Goodman Damon H.
Published: June 2016

Pacific Lamprey Entosphenus tridentatus have been overlooked historically in fish surveys using standard salmonid methods along the Pacific coast of North America. As a result, little is known of even their broader distribution patterns at the drainage level. Over the last 2 decades, the species has shown a northward range contraction of over 900 km, and at this time the southernmost population is the Big Sur River in California. This study evaluates the hypothesis that Pacific Lampreys do not typically utilize relatively small coastal drainages (<100 km2). We examined historical Pacific Lamprey records throughout California and surveyed 349 current sites in 102 coastal drainages along the California coastline and into Baja California. Within their currently occupied range (north of Big Sur), Pacific Lampreys were found in all drainages >100 km2, but in only 3 of 29 drainages <50 km2, and they were absent in all drainages <25 km2. All historical records are from drainages >50 km2, and primarily from larger drainages in southern California. Our results will support greater exploration of the ecological roles of lampreys in coastal streams, where they act as importers of marine nutrients, substrate engineers and filter feeders, as well as providing a rich prey base for many species. This paper also provides resource managers with an understanding of where Pacific Lampreys are likely to be found and where they were probably not a natural component of the fish fauna, allowing prioritization of conservation actions and more effective use of resources.

Received December 3, 2015; accepted February 22, 2016 Published online June 15, 2016