bluuebunny/crossref_metadata_2025 huggingface dataset:
Tuning thermal conductivity in homoepitaxial SrTiO3 films via defects
Authors: Brooks Charles M. , Wilson Richard B. , Schäfer Anna , Mundy Julia A. , Holtz Megan E. , Muller David A. , Schubert Jürgen , Cahill David G. , Schlom Darrell G.
Published: August 2015

We demonstrate the ability to tune the thermal conductivity of homoepitaxial SrTiO3 films deposited by reactive molecular-beam epitaxy by varying growth temperature, oxidation environment, and cation stoichiometry. Both point defects and planar defects decrease the longitudinal thermal conductivity (k33), with the greatest decrease in films of the same composition observed for films containing planar defects oriented perpendicular to the direction of heat flow. The longitudinal thermal conductivity can be modified by as much as 80%—from 11.5 W m−1K−1 for stoichiometric homoepitaxial SrTiO3 to 2 W m−1K−1 for strontium-rich homoepitaxial Sr1+δTiOx films—by incorporating (SrO)2 Ruddlesden-Popper planar defects.
Consistent structures and interactions by density functional theory with small atomic orbital basis sets
Authors: Grimme Stefan , Brandenburg Jan Gerit , Bannwarth Christoph , Hansen Andreas
Published: August 2015

A density functional theory (DFT) based composite electronic structure approach is proposed to efficiently compute structures and interaction energies in large chemical systems. It is based on the well-known and numerically robust Perdew-Burke-Ernzerhoff (PBE) generalized-gradient-approximation in a modified global hybrid functional with a relatively large amount of non-local Fock-exchange. The orbitals are expanded in Ahlrichs-type valence-double zeta atomic orbital (AO) Gaussian basis sets, which are available for many elements. In order to correct for the basis set superposition error (BSSE) and to account for the important long-range London dispersion effects, our well-established atom-pairwise potentials are used. In the design of the new method, particular attention has been paid to an accurate description of structural parameters in various covalent and non-covalent bonding situations as well as in periodic systems. Together with the recently proposed three-fold corrected (3c) Hartree-Fock method, the new composite scheme (termed PBEh-3c) represents the next member in a hierarchy of “low-cost” electronic structure approaches. They are mainly free of BSSE and account for most interactions in a physically sound and asymptotically correct manner. PBEh-3c yields good results for thermochemical properties in the huge GMTKN30 energy database. Furthermore, the method shows excellent performance for non-covalent interaction energies in small and large complexes. For evaluating its performance on equilibrium structures, a new compilation of standard test sets is suggested. These consist of small (light) molecules, partially flexible, medium-sized organic molecules, molecules comprising heavy main group elements, larger systems with long bonds, 3d-transition metal systems, non-covalently bound complexes (S22 and S66×8 sets), and peptide conformations. For these sets, overall deviations from accurate reference data are smaller than for various other tested DFT methods and reach that of triple-zeta AO basis set second-order perturbation theory (MP2/TZ) level at a tiny fraction of computational effort. Periodic calculations conducted for molecular crystals to test structures (including cell volumes) and sublimation enthalpies indicate very good accuracy competitive to computationally more involved plane-wave based calculations. PBEh-3c can be applied routinely to several hundreds of atoms on a single processor and it is suggested as a robust “high-speed” computational tool in theoretical chemistry and physics.
An improved potential energy surface and multi-temperature quasiclassical trajectory calculations of N2 + N2 dissociation reactions
Authors: Bender Jason D. , Valentini Paolo , Nompelis Ioannis , Paukku Yuliya , Varga Zoltan , Truhlar Donald G. , Schwartzentruber Thomas , Candler Graham V.
Published: August 2015

Accurate modeling of high-temperature hypersonic flows in the atmosphere requires consideration of collision-induced dissociation of molecular species and energy transfer between the translational and internal modes of the gas molecules. Here, we describe a study of the N2 + N2⟶N2 + 2N and N2 + N2⟶4N nitrogen dissociation reactions using the quasiclassical trajectory (QCT) method. The simulations used a new potential energy surface for the N4 system; the surface is an improved version of one that was presented previously. In the QCT calculations, initial conditions were determined based on a two-temperature model that approximately separates the translational-rotational temperature from the vibrational temperature of the N2 diatoms. Five values from 8000 K to 30 000 K were considered for each of the two temperatures. Over 2.4 × 109 trajectories were calculated. We present results for ensemble-averaged dissociation rate constants as functions of the translational-rotational temperature T and the vibrational temperature Tv. The rate constant depends more strongly on T when Tv is low, and it depends more strongly on Tv when T is low. Quasibound reactant states contribute significantly to the rate constants, as do exchange processes at higher temperatures. We discuss two sets of runs in detail: an equilibrium test set in which T = Tv  and a nonequilibrium test set in which Tv < T. In the equilibrium test set, high-v and moderately-low-j molecules contribute most significantly to the overall dissociation rate, and this state specificity becomes stronger as the temperature decreases. Dissociating trajectories tend to result in a major loss of vibrational energy and a minor loss of rotational energy. In the nonequilibrium test set, as Tv decreases while T is fixed, higher-j molecules contribute more significantly to the dissociation rate, dissociating trajectories tend to result in a greater rotational energy loss, and the dissociation probability’s dependence on v weakens. In this way, as Tv decreases, rotational energy appears to compensate for the decline in average vibrational energy in promoting dissociation. In both the equilibrium and nonequilibrium test sets, in every case, the average total internal energy loss in the dissociating trajectories is between 10.2 and 11.0 eV, slightly larger than the equilibrium potential energy change of N2 dissociation.
Development of high vorticity structures in incompressible 3D Euler equations
Authors: Agafontsev D. S. , Kuznetsov E. A. , Mailybaev A. A.
Published: August 2015

We perform the systematic numerical study of high vorticity structures that develop in the 3D incompressible Euler equations from generic large-scale initial conditions. We observe that a multitude of high vorticity structures appear in the form of thin vorticity sheets (pancakes). Our analysis reveals the self-similarity of the pancakes evolution, which is governed by two different exponents e−t/Tℓ and et/Tω describing compression in the transverse direction and the vorticity growth, respectively, with the universal ratio Tℓ/Tω ≈ 2/3. We relate development of these structures to the gradual formation of the Kolmogorov energy spectrum Ek ∝  k−5/3, which we observe in a fully inviscid system. With the spectral analysis, we demonstrate that the energy transfer to small scales is performed through the pancake structures, which accumulate in the Kolmogorov interval of scales and evolve according to the scaling law ωmax ∝ ℓ−2/3 for the local vorticity maximums ωmax and the transverse pancake scales ℓ.
Profile simulation model for sub-50 nm cryogenic etching of silicon using SF6/O2 inductively coupled plasma
Authors: Ishchuk Valentyn , Olynick Deirdre L. , Liu Zuwei , Rangelow Ivo W.
Published: August 2015

Cryogenic etching of silicon is a route to high aspect ratio silicon features with high mask selectivity and smooth sidewalls. These benefits have been realized even down to 10 nm half-pitch features. In this work, we develop a semi-empirical simulation model to understand mechanisms responsible for nanoscale profile evolution during plasma etching of silicon in SF6/O2 chemistry at cryogenic temperatures. The model parameters are first calibrated to the etching equipment using features from 500 nm to 2 μm. Using the calibrated model, we show the experimental finding that smaller features need more oxygen to achieve vertical anisotropic profiles. This is a consequence of two related effects: (1) the SiOxFy passivation layer sputtering yield is strongly dependent on the oxygen content at the feature sidewalls and (2) Knudsen transport within small features or higher aspect ratios depletes oxygen faster than fluorine due to the higher sticking coefficient of oxygen. The simulation was applied to 25 nm half-pitch features with excellent results.
Resonant-like behaviour during edge-localised mode cycles in the Joint European Torus
Authors: Webster A. J. , Morris J. , Todd T. N. , Brezinsek S. , Coad P. , Likonen J. , Rubel M. ,   JET EFDA Contributors
Published: August 2015

A unique sequence of 120 almost identical plasmas in the Joint European Torus (JET) recently provided two orders of magnitude more statistically equivalent data than ever previously available. The purpose was to study movement of eroded plasma-facing material from JET's new Beryllium wall, but it has allowed the statistical detection of otherwise unobservable phenomenon. This includes a sequence of resonant-like waiting times between edge-localised plasma instabilities (ELMs), instabilities that must be mitigated or avoided in large magnetically confined plasmas such as those planned for ITER. Here, we investigate the cause of this phenomenon, using the unprecedented quantity of data to produce a detailed picture of the plasma's behaviour. After combining the data, oscillations are clearly observable in the plasma's vertical position, in edge losses of ions, and in Beryllium II (527 nm) light emissions. The oscillations are unexpected, are not obvious in data from a single pulse alone, and are all clearly correlated with each other. They are likely to be caused by a small vertical oscillation that the plasma control system is not reacting to prevent, but a more complex explanation is possible. The clearly observable but unexpected link between small changes in the plasma's position and changes to edge-plasma transport and stability suggest that these characteristics cannot always be studied in isolation. It also suggests new opportunities for ELM mitigation and control that may exist.
Investigation of self-oscillation using particle balance model
Authors: Bae Inshik , Na Byungkeun , Chang Hongyoung
Published: August 2015

Self-oscillation obtained using a DC-only power supply under specific anode voltage conditions is investigated in a cylindrical system with thermal electrons using tungsten filaments. Analysis of the obtained oscillation profiles reveals that the experimental data are consistent with a model derived from the particle balance model. The self-oscillation period characteristics with respect to the pressure and gas species are also analyzed. As the physics and particle motion of self-oscillation near the plasma transition region are analyzed from different perspectives, this paper may advance the study of this phenomenon.
Stability of Brillouin flow in planar, conventional, and inverted magnetrons
Authors: Simon D. H. , Lau Y. Y. , Greening G. , Wong P. , Hoff B. W. , Gilgenbach R. M.
Published: August 2015

The Brillouin flow is the prevalent flow in crossed-field devices. We systematically study its stability in the conventional, planar, and inverted magnetron geometry. To investigate the intrinsic negative mass effect in Brillouin flow, we consider electrostatic modes in a nonrelativistic, smooth bore magnetron. We found that the Brillouin flow in the inverted magnetron is more unstable than that in a planar magnetron, which in turn is more unstable than that in the conventional magnetron. Thus, oscillations in the inverted magnetron may startup faster than the conventional magnetron. This result is consistent with simulations, and with the negative mass property in the inverted magnetron configuration. Inclusion of relativistic effects and electromagnetic effects does not qualitatively change these conclusions.
Numerical self-consistent field theory study of the response of strong polyelectrolyte brushes to external electric fields
Authors: Tong Chaohui
Published: August 2015

The response of strong polyelectrolyte (PE) brushes grafted on an electrode to electric fields generated by opposite surface charges on the PE-grafted electrode and a second parallel electrode has been numerically investigated by self-consistent field theory. The influences of grafting density, average charge fraction, salt concentration, and mobile ion size on the variation of the brush height against an applied voltage bias were investigated. In agreement with molecular dynamics simulation results, a higher grafting density requires a larger magnitude of voltage bias to achieve the same amount of relative change in the brush height. In the experimentally relevant parameter regime of the applied voltage, the brush height becomes insensitive to the voltage bias when the grafting density is high. Including the contribution of surface charges on the grafting electrode, overall charge neutrality inside the PE brushes is generally maintained, especially for PE brushes with high grafting density and high average charge fraction. Our numerical study further reveals that the electric field across the two electrodes is highly non-uniform because of the complex interplay between the surface charges on the electrodes, the charges on the grafted PE chains, and counterions.
Validation of full-wave simulations for mode conversion of waves in the ion cyclotron range of frequencies with phase contrast imaging in Alcator C-Mod
Authors: Tsujii N. , Porkolab M. , Bonoli P. T. , Edlund E. M. , Ennever P. C. , Lin Y. , Wright J. C. , Wukitch S. J. , Jaeger E. F. , Green D. L. , Harvey R. W.
Published: August 2015

Mode conversion of fast waves in the ion cyclotron range of frequencies (ICRF) is known to result in current drive and flow drive under optimised conditions, which may be utilized to control plasma profiles and improve fusion plasma performance. To describe these processes accurately in a realistic toroidal geometry, numerical simulations are essential. Quantitative comparison of these simulations and the actual experimental measurements is important to validate their predictions and to evaluate their limitations. The phase contrast imaging (PCI) diagnostic has been used to directly detect the ICRF waves in the Alcator C-Mod tokamak. The measurements have been compared with full-wave simulations through a synthetic diagnostic technique. Recently, the frequency response of the PCI detector array on Alcator C-Mod was recalibrated, which greatly improved the comparison between the measurements and the simulations. In this study, mode converted waves for D-3He and D-H plasmas with various ion species compositions were re-analyzed with the new calibration. For the minority heating cases, self-consistent electric fields and a minority ion distribution function were simulated by iterating a full-wave code and a Fokker-Planck code. The simulated mode converted wave intensity was in quite reasonable agreement with the measurements close to the antenna, but discrepancies remain for comparison at larger distances.
Study of harsh environment operation of flexible ferroelectric memory integrated with PZT and silicon fabric
Authors: Ghoneim M. T. , Hussain M. M.
Published: August 2015

Flexible memory can enable industrial, automobile, space, and smart grid centered harsh/extreme environment focused electronics application(s) for enhanced operation, safety, and monitoring where bent or complex shaped infrastructures are common and state-of-the-art rigid electronics cannot be deployed. Therefore, we report on the physical-mechanical-electrical characteristics of a flexible ferroelectric memory based on lead zirconium titanate as a key memory material and flexible version of bulk mono-crystalline silicon (100). The experimented devices show a bending radius down to 1.25 cm corresponding to 0.16% nominal strain (high pressure of ∼260 MPa), and full functionality up to 225 °C high temperature in ambient gas composition (21% oxygen and 55% relative humidity). The devices showed unaltered data retention and fatigue properties under harsh conditions, still the reduced memory window (20% difference between switching and non-switching currents at 225 °C) requires sensitive sense circuitry for proper functionality and is the limiting factor preventing operation at higher temperatures.
Local impedance measurement of an electrode/single-pentacene-grain interface by frequency-modulation scanning impedance microscopy
Authors: Kimura Tomoharu , Kobayashi Kei , Yamada Hirofumi
Published: August 2015

The device performances of organic thin film transistors are often limited by the metal–organic interface because of the disordered molecular layers at the interface and the energy barriers against the carrier injection. It is important to study the local impedance at the interface without being affected by the interface morphology. We combined frequency modulation atomic force microscopy with scanning impedance microscopy (SIM) to sensitively measure the ac responses of the interface to an ac voltage applied across the interface and the dc potential drop at the interface. By using the frequency-modulation SIM (FM-SIM) technique, we characterized the interface impedance of a Pt electrode and a single pentacene grain as a parallel circuit of a contact resistance and a capacitance. We found that the reduction of the contact resistance was caused by the reduction of the energy level mismatch at the interface by the FM-SIM measurements, demonstrating the usefulness of the FM-SIM technique for investigation of the local interface impedance without being affected by its morphology.
Superparamagnetic nanoparticle-based viscosity test
Authors: Wu Kai , Liu Jinming , Wang Yi , Ye Clark , Feng Yinglong , Wang Jian-Ping
Published: August 2015

Hyperviscosity syndrome is triggered by high blood viscosity in the human body. This syndrome can result in retinopathy, vertigo, coma, and other unanticipated complications. Serum viscosity is one of the important factors affecting whole blood viscosity, which is regarded as an indicator of general health. In this letter, we propose and demonstrate a Brownian relaxation-based mixing frequency method to test human serum viscosity. This method uses excitatory and detection coils and Brownian relaxation-dominated superparamagnetic nanoparticles, which are sensitive to variables of the liquid environment such as viscosity and temperature. We collect the harmonic signals produced by magnetic nanoparticles and estimate the viscosity of unknown solutions by comparison to the calibration curves. An in vitro human serum viscosity test is performed in less than 1.5 min.
Weakly nonlinear Bell-Plesset effects for a uniformly converging cylinder
Authors: Wang L. F. , Wu J. F. , Guo H. Y. , Ye W. H. , Liu Jie , Zhang W. Y. , He X. T.
Published: August 2015

In this research, a weakly nonlinear (WN) model has been developed considering the growth of a small perturbation on a cylindrical interface between two incompressible fluids which is subject to arbitrary radial motion. We derive evolution equations for the perturbation amplitude up to third order, which can depict the linear growth of the fundamental mode, the generation of the second and third harmonics, and the third-order (second-order) feedback to the fundamental mode (zero-order). WN solutions are obtained for a special uniformly convergent case. WN analyses are performed to address the dependence of interface profiles, amplitudes of inward-going and outward-going parts, and saturation amplitudes of linear growth of the fundamental mode on the Atwood number, the mode number (m), and the initial perturbation. The difference of WN evolution in cylindrical geometry from that in planar geometry is discussed in some detail. It is shown that interface profiles are determined mainly by the inward and outward motions rather than bubbles and spikes. The amplitudes of inward-going and outward-going parts are strongly dependent on the Atwood number and the initial perturbation. For low-mode perturbations, the linear growth of fundamental mode cannot be saturated by the third-order feedback. For fixed Atwood numbers and initial perturbations, the linear growth of fundamental mode can be saturated with increasing m. The saturation amplitude of linear growth of the fundamental mode is typically 0.2λ–0.6λ for m < 100, with λ being the perturbation wavelength. Thus, it should be included in applications where Bell-Plesset [G. I. Bell, Los Alamos Scientific Laboratory Report No. LA-1321, 1951; M. S. Plesset, J. Appl. Phys. 25, 96 (1954)] converging geometry effects play a pivotal role, such as inertial confinement fusion implosions.
Measurement and modeling of electric field and space-charge distributions in obstructed helium discharge
Authors: Fendel Peter , Ganguly Biswa N. , Bletzinger Peter
Published: August 2015

Axial and radial variations of electric field have been measured in dielectric shielded 0.025 m diameter parallel plate electrode with 0.0065 m gap for 1.6 mA, 2260 V helium dc discharge at 1.75 Torr. The axial and radial electric field profiles have been measured from the Stark splitting of 21S→11 1P transition through collision induced fluorescence from 43D→23P. The electric field values showed a strong radial variation peaking to 500 kV/m near the cathode radial boundary, and decreasing to about 100 kV/m near the anode edge, suggesting the formation of an obstructed discharge for this low nd condition, where n is the gas density and d is the gap distance. The off-axis Stark spectra showed that the electric field vector deviates from normal to the cathode surface which permits longer path electron trajectories in the inter-electrode gap. Also, the on-axis electric field gradient was very small and off-axis electric field gradient was large indicating a radially non-uniform current density. In order to obtain information about the space charge distribution in this obstructed discharge, it was modeled using the 2-d axisymmetric Poisson solver with the COMSOL finite element modeling program. The best fit to the measured electric field distribution was obtained with a space charge variation of ρ(r) = ρ0(r/r0)3, where ρ(r) is the local space charge density, ρ0 = 6 × 10−3 Coulomb/m3, r is the local radial value, and r0 is the radius of the electrode.
Non-contact optoacoustic imaging with focused air-coupled transducers
Authors: Deán-Ben X. Luís , Pang Genny A. , Montero de Espinosa Francisco , Razansky Daniel
Published: August 2015

Non-contact optoacoustic imaging employing raster-scanning of a spherically focused air-coupled ultrasound transducer is showcased herein. Optoacoustic excitation with laser fluence within the maximal permissible human exposure limits in the visible and near-infrared spectra is applied to objects with characteristic dimensions smaller than 1 mm and absorption properties representative of the whole blood at near-infrared wavelengths, and these signals are shown to be detectable without contact to the sample using an air-coupled transducer with reasonable signal averaging. Optoacoustic images of vessel-mimicking tubes embedded in an agar phantom captured with this non-contact sensing technique are also showcased. These initial results indicate that an air-coupled ultrasound detection approach can be suitable for non-contact biomedical imaging with optoacoustics.
Domain configuration changes under electric field-induced antiferroelectric-ferroelectric phase transitions in NaNbO3-based ceramics
Authors: Guo Hanzheng , Shimizu Hiroyuki , Mizuno Youichi , Randall Clive A.
Published: August 2015

We recently developed a feasible crystal chemistry strategy to stabilize the antiferroelectricity in NaNbO3 through a chemical substitution to decrease the tolerance factor and increase the average electronegativity of the system [Shimizu et al., Dalton Trans. 44, 10763 (2015) and Guo et al., J. Appl. Phys. 117, 214103 (2015)]. Two novel lead-free antiferroelectric (AFE) solid solutions, (1-x)NaNbO3-xCaZrO3 and (1-x)NaNbO3-xSrZrO3, have been found to exhibit the double polarization hysteresis typical of a reversible AFE ↔ ferroelectric (FE) phase transition. In this study, as demonstrated by (1-x)NaNbO3-xCaZrO3 system, the influence of chemical modification and electrical poling on the AFE/FE phase stability was investigated, primarily focusing on the microstructural and crystallographic evolutions. Together with the macroscopic polarization hysteresis measurements, a well-demonstrated structure-property relationship was presented. It was found that the CaZrO3 substitution into NaNbO3 can effectively destabilize the FE Q phase and correspondingly lead to a spontaneous reverting to AFE P phase. In contrast to the reversible AFE ↔ FE phase transition, the domain morphology evolution exhibits irreversible nature with a growing process of the orientational domains after applying electric field. Moreover, a multiple-zone axes electron diffraction map of P and Q phases has been summarized and is believed to be an efficient diagram to determine the AFE/FE nature of the NaNbO3-based systems.
Stimulus-responsive colloidal sensors with fast holographic readout
Authors: Wang Chen , Moyses Henrique W. , Grier David G.
Published: August 2015

Colloidal spheres synthesized from polymer gels swell by absorbing molecules from solution. The resulting change in size can be monitored with nanometer precision using holographic video microscopy. When the absorbate is chemically similar to the polymer matrix, swelling is driven primarily by the entropy of mixing, and is limited by the surface tension of the swelling sphere and by the elastic energy of the polymer matrix. We demonstrate through a combination of optical micromanipulation and holographic particle characterization that the degree of swelling of a single polymer bead can be used to measure the monomer concentration in situ with spatial resolution comparable to the size of the sphere.
Al2O3 as a suitable substrate and a dielectric layer for n-layer MoS2
Authors: Singh Arunima K. , Hennig Richard G. , Davydov Albert V. , Tavazza Francesca
Published: August 2015

Sapphire (α-Al2O3) is a common substrate for the growth of single- to few-layer MoS2 films, and amorphous aluminium oxide serves as a high-κ dielectric gate oxide for MoS2 based transistors. Using density-functional theory calculations with a van der Waals functional, we investigate the structural, energetic, and electronic properties of n-layer MoS2 (n = 1and 3) on the α-Al2O3 (0001) surface. Our results show that the sapphire stabilizes single-layer and tri-layer MoS2, while having a negligible effect on the structure, band gap, and electron effective masses of MoS2. This combination of a strong energetic stabilization and weak perturbation of the electronic properties shows that α-Al2O3 can serve as an ideal substrate for depositing ultra-thin MoS2 layers and can also serve as a passivation or gate-oxide layer for MoS2 based devices.
The interfacial layer effect on bi-stable resistive switching phenomenon in MnOx thin film
Authors: Yang Min Kyu , Kim Gun Hwan , Ju Hyunsu , Lee Jeon-Kook , Ryu Han-Cheol
Published: August 2015

Resistive switching behavior of MnOx thin films was comparatively investigated. Two different top electrode materials of Ti and Pt over the common MnOx/Pt structure showed significantly distinct electrical endurance characteristics. Various structural and electrical analyses revealed that the interfacial oxide layer associated with Ti in the Ti/MnOx/Pt structure affected the improved electrical endurance characteristic. Finally, an 8 × 8 crossbar array with 100 nm-width interconnection line was fabricated to confirm the scalability and the stability of the resistive switching performances in the Ti/MnOx/Pt structure.
Nuclear receptor RORα regulates pathologic retinal angiogenesis by modulating SOCS3-dependent inflammation
Authors: Sun Ye , Liu Chi-Hsiu , SanGiovanni John Paul , Evans Lucy P. , Tian Katherine T. , Zhang Bing , Stahl Andreas , Pu William T. , Kamenecka Theodore M. , Solt Laura A. , Chen Jing
Published: August 2015

Significance

Pathologic retinal neovascularization commonly causes blindness. Retinoic-acid-receptor–related orphan receptor alpha (RORα), a lipid-sensing nuclear receptor, is genetically associated with the risk of developing neovascular eye disease in humans. We demonstrate that RORα expression was highly increased in a mouse model of oxygen-induced proliferative retinopathy with pathologic neovessels. Both genetic deficiency and pharmacologic inhibition of RORα suppressed pathologic retinal neovascularization in mice with dampened inflammation. RORα transcriptionally regulated suppressors of cytokine signaling 3 (SOCS3), a negative mediator of macrophage function and inflammation. Suppression of SOCS3 attenuated the protective effects of RORα inhibition in retinopathy. Our data demonstrate an important role of RORα in controlling pathologic retinal neovascularization and suggest that RORα may represent a druggable target for treating ocular neovascularization.
The crystal structures of three 3-methyl-1H-1,2,4-triazole-5-thiones, including a second polymorph of 4-[(E)-(5-bromo-2-hydroxybenzylidene)amino]-3-methyl-1H-1,2,4-triazole-5(4H)-thione and a redetermination of 4-amino-3-methyl-1H-1,2,4-triazole-5(4H)-thione
Authors: Manjula Padmanabha S. , Sarojini Balladka K. , Yathirajan Hemmige S. , Akkurt Mehmet , Ersanlı Cem Cüneyt , Glidewell Christopher
Published: August 2015

The structures of three 3-methyl-1H-1,2,4-triazole-5-thione derivatives are reported. The structure of 4-amino-3-methyl-1H-1,2,4-triazole-5(4H)-thione, C3H6N4S, (I), has been redetermined with an improved model for the H atoms: the non-H atoms of (I) all lie on mirror planes in space groupPbcm, and the H atoms of the methyl group are disordered over two sets of reflection-related atomic sites having occupancy 0.5: two independent N—H...S hydrogen bonds link the molecules of compound (I) into complex sheets. The non-H atoms in the molecules of 4-[(E)-(3,4-dimethoxybenzylidene)amino]-3-methyl-1H-1,2,4-triazol-5(4H)-thione, C12H14N4O2S, (II), despite lying in general positions are close to planar, with a dihedral angle between the two rings of 6.31 (10)°: the molecules of compound (II) are linked by a three-centre N—H...(O)2hydrogen bond into aC(10)C(11)[R12(5)] chain of rings. A second polymorph of 4-[(E)-(5-bromo-2-hydroxy-5-bromobenzylidene)amino]-3-methyl-1H-1,2,4-triazole-5(4H)-thione, C10H9BrN4OS, (III), has been identified; the non-H atoms are nearly co-planar with a dihedral angle between the two rings of 1.9 (4)°. There is an intramolecular O—H...N hydrogen bond and the molecules are linked by N—H...S hydrogen bonds, forming centrosymmetricR22(8) dimers. Comparisons are made with some related structures.
Crystal structure of octa-μ3-selenido-(p-toluenesulfonato-κO)pentakis(triethylphosphane-κP)-octahedro-hexarhenium(III)p-toluenesulfonate dichloromethane disolvate
Authors: Edwards Julia A. , McDonald Robert , Szczepura Lisa F.
Published: August 2015

The title compound, [Re6Se8{O3SC6H4(CH3)}{P(C2H5)3}5](CH3C6H4SO3)·2CH2Cl2, contains the face-capped hexanuclear [Re6(μ3-Se)8]2+cluster core. The [Re6Se8]2+cluster core displays a non-crystallographic center of symmetry and is bonded through the ReIIIatoms to five triethylphosphane ligands and onep-toluenesulfonate ligand. Onep-toluenesulfonate counter-ion and two dichloromethane solvent molecules are also present in the asymmetric unit. One of the ethyl chains of one triethylphosphane ligand and one of the CH2Cl2solvent molecules are disordered over two sets of sites (occupancy ratios 0.65:0.35 and 0.5:0.5, respectively). The Re—O(sulfonate) bond length of 2.123 (5) Å is similar to other Re—O bond lengths of hexanuclear rhenium chalcogenide clusters containing otherO-donor ligands such as dimethyl sulfoxide (DMSO), dimethylformamide (DMF) and hydroxide.
Crystal structure of 2-methylamino-4-(6-methyl-4-oxo-4H-chromen-3-yl)-3-nitropyrano[3,2-c]chromen-5(4H)-one with an unknown solvate
Authors: Raja Rajamani , Kandhasamy Subramani , Perumal Paramasivam T. , SubbiahPandi A.
Published: August 2015

In the title compound, C23H16N2O7, the mean planes of the two chromene units (r.m.s. deviations = 0.031 and 0.064 Å) are almost normal to one another with a dihedral angle of 85.59 (6)°. The central six-membered pyran ring has a distorted envelope conformation, with the methine C atom at the flap. There is an intramolecular N—H...O hydrogen bond, which generates anS(6) ring motif. In the crystal, molecules are linked by pairs of N—H...O hydrogen bonds, forming inversion dimers with anR22(12) ring motif. The dimers are linked by pairs of C—H...O hydrogen bonds, enclosingR22(6) ring motifs, forming zigzag chains along [001]. The chains are linked by a second pair of C—H...O hydrogen bonds, forming slabs parallel to (110). Within the slabs there are C—H...π interactions present. A region of disordered electron density was treated with the SQUEEZE procedure inPLATON[Spek (2015).Acta Cryst.C71, 9–18] following unsuccessful attempts to model it as plausible solvent molecule(s). The given chemical formula and other crystal data do not take into account the unknown solvent molecule(s).
Crystal structure and absolute configuration of (3aS,4S,5R,7aR)-2,2,7-trimethyl-3a,4,5,7a-tetrahydro-1,3-benzodioxole-4,5-diol
Authors: Macías Mario A. , Suescun Leopoldo , Pandolfi Enrique , Schapiro Valeria , Tibhe Gaurao D. , Mombrú Álvaro W.
Published: August 2015

The absolute configuration of the title compound, C10H16O4, determined as 3aS,4S,5R,7aRon the basis of the synthetic pathway, was confirmed by X-ray diffraction. The molecule contains a five- and a six-membered ring that adopt twisted and envelope conformations, respectively. The dihedral angle between the mean planes of the rings is 76.80 (11)° as a result of theircis-fusion. In the crystal, molecules are linked by two pairs of O—H...O hydrogen bonds, forming chains along [010]. These chains are further connected by weaker C—H...O interactions along [100], creating (001) sheets that interact only by weak van der Waals forces.
Associative dimension in World Heritage: an analysis of criterion (vi)
Authors: Herrmann Judith , Cameron Christina
Published: August 2015

Purpose

– This paper is based on a presentation given at the international World Heritage expert meeting on criterion (vi) held in Warsaw, Poland, in March 2012. Results were updated and adapted to scientific standards. The purpose of this paper is to understand the associative dimension in World Heritage by looking at the evolution and application of criterion (vi).

Design/methodology/approach

– For this paper, historical and qualitative approaches were combined. An understanding of the evolution of the criterion (vi) wording was gained through historical analysis and the consultation of relevant World Heritage statutory documents. A selected number of criterion (vi) statements were analyzed in qualitative terms. Results were then discussed in relation to the evolution of criterion (vi) wording and the understanding of pertinent World Heritage concepts.

Findings

– Criterion (vi) holds a special position. It addresses an associative dimension of cultural World Heritage sites. Due to its special character, its wording was subject to several changes. While its wording became ever more flexible, this development has not fostered the inscription of exceptional cases or the equal use of cultural associations. An inconsistent interpretation has also weakened the concept of Outstanding Universal Value.

Research limitations/implications

– Only inscriptions were taken into consideration. They usually have a World Heritage Committee approved criterion (vi) statement. Limitations to this research result from this restriction.

Originality/value

– The paper represents a comprehensive study of the application and interpretation of criterion (vi) that combines the understanding of the evolution of the criterion’s wording with the analysis of a large number of World Heritage inscriptions. It is of interest to the World Heritage community and contributes to the World Heritage discourse.
Does outcome quality matter? An investigation in the context of banking services in an emerging market
Authors: Jain Sonali , Jain Sanjay K.
Published: August 2015

Purpose

– This paper aims to measure outcome quality in banks in India and to make a comparative assessment of its influence on customer service quality perceptions. Though both functional quality (i.e. how service is delivered) and outcome quality (i.e. what is delivered) are important aspects of service quality, it is the functional quality which has primarily been the focus of past studies.

Design/methodology/approach

– The data used in the study are based on a survey of bank customers located in Delhi and National Capital Region. Using the exploratory factor analysis and confirmatory factor analysis, validity and dimensionality of the multi-item functional and outcome quality scales used in the study were assessed. A structural model of relationships of functional and outcome quality with overall service quality was tested through use of the structural equation modeling (SEM) approach.

Findings

– The study finds outcome quality as being a significant and major determinant of customer service quality perceptions in banks. Inclusion of outcome quality in the analysis is, moreover, found to be helpful in capturing more exhaustively the variations present in customer overall service quality perceptions.

Research limitations/implications

– Both the functional and outcome quality in the study have been measured through scales adapted from past studies. But the same have not been found able to fully capture variations in customer service quality perceptions. More psychometrically sound scales to measure functional and outcome quality are needed. Studies in both the developing and developed countries and additional service sectors are called for to increase the generalizability of the study findings. Furthermore, nomological validity of the outcome quality scale needs to be investigated by relating it with other anent constructs, such as customer satisfaction and their behavioral intentions.

Practical implications

– Instead of simply remaining preoccupied with functional quality, i.e. process or how part of service delivery, bank management also needs to gauze customer outcome quality perceptions (i.e. what the customers think they are eventually getting out of their transactions with the service provider) and exercise due care to see that customers in fact are getting the core banking tasks performed for which they approach the banks in the first instance.

Originality/value

– Present study is first of its kind in investigating role of outcome quality in banking services sector in the context of an emerging market like India. Use of SEM for analyzing both the measurement and structural models constitutes another noteworthy feature of the study.
Assessing performance and impact of the Technological Districts (TDs): general modelling and measurement system
Authors: Lerro Antonio , Schiuma Giovanni
Published: August 2015

Purpose

– This paper aims to define a general model to identify and assess performance and impacts of the technology districts (TDs), paying great attention to avoid confusion on contents and methods as well as overlapping of economic, financial and managerial dimensions of performance and impact that often have characterized the academic and policy literature. Although over the past years the emphasis on knowledge and science-based resources has strongly contributed to create a wide acknowledgement of the relevance of the TDs for the national and local development paths, there is still a need for a better understanding about the assessment of the TDs’ performance and impacts.

Design/methodology/approach

– First, a literature review – both at academic and practitioners’ and policy level – was performed using a systematic approach. Then, a rigorous Delphi methodology was designed and implemented to identify and select the most important issues of interest of the research by soliciting qualified experts.

Findings

– Based on this research, a well-grounded set of macro-areas and specific indicators aimed to assess performance and impact of the TDs is proposed from which researchers and policymakers can choose those which are more fitted to the needs of their studies and as a way to define the specific focus of their investigation.

Practical implications

– The definition of this general model has the objective to support the elaboration of a structured set of managerial and policy implications able to drive, respectively, the management in the strategy formulation and implementation, as well as in the actions for the performance improvement, and the decision-makers in the elaboration of effective policies of development and correct evaluation of the impact of the TDs on the different places.

Originality/value

– This paper contributes at theoretical and practical level to improve the managerial and policy methods and tools to identify, assess, manage and report the performance and the impact of the TDs. The originality and the value of the paper resides in its attempt to improve and to let more shared and transparent the informative quality on which the TDs are called to operate and report to the stakeholders, in particular regulators and public organizations. Moreover, this paper will hopefully stimulate a debate and encourage a greater level of clarity, generalizability and comparability in the TDs performance measurement systems research stream.
Market reaction to the Karachi stock exchange floor imposition
Authors: Sharif Saqib
Published: August 2015

Purpose

– The purpose of this paper is to investigate the market reaction to the decision made by the management of the Karachi Stock Exchange (KSE) to impose a price floor that resulted in trading curbs in 2008. The paper analyzes if regulatory intervention helped in restoring investor confidence.

Design/methodology/approach

– The paper examines the effect of enforcement of a price floor and trading curbs by splitting the time period studied into two periods: pre-floor and post-floor period. The parametric t-statistics and non-parametric Mann-Whitney test are used to compare the abnormal returns (ARs), abnormal trading volume, bid-ask spread, Amihud illiquidity ratio, and price volatility between the two periods. Event study was conducted to observe the behavior of market returns surrounding market-wide price floor. Finally, multivariate regression analysis was also applied by controlling for factors that might influence valuation, liquidity, and volatility. The standard errors have been corrected for cross-sectional clustering due to market-wide restrictions.

Findings

– The study found an adverse impact of price freeze and trading curb in the KSE, following the relaxation of floor (resumption of active trading). First, the price of securities (or ARs) significantly declined following the relaxation of the price freeze. Second, the market liquidity deteriorated following the relaxation of the price floor. Third, the price volatility increased in the post-floor period. It seems that the decision made by the KSE’s board to implement lower cap on prices for an extended period was ineffective.

Practical implications

– Market intervention by regulators to bring calm in the financial markets have negative consequences across the globe. The results presented in this paper suggest that implementing price floor brought inefficiency in the market and prevented firms from raising capital to finance their future investments. The author believe this study will add to the knowledge base of regulatory intervention and its impact on the performance of financial markets.

Originality/value

– There is no empirical evidence on the impact of price limits on volatility in emerging markets. The author selected Pakistan as a case study, where we particularly focus upon impact of the enforcement of a price floor around the peak of Global Financial Crisis (or market intervention) in Pakistan. This study also documents the effect of trading curb on liquidity and volatility in an emerging market, given that a majority of research on trading halt/price limits is based on developed markets.
Exploring the connection between quality management and brain functioning
Authors: Lagrosen Yvonne , Travis Frederick T.
Published: August 2015

Purpose

– The purpose of this paper is to explore possible connections between brain functioning and quality management.

Design/methodology/approach

– Five central principles regarding brain functioning according to neuroscience are conceptually described and related to principles and major concepts in quality management with a special emphasis on Deming’s system of profound knowledge.

Findings

– The principles are shown to be related in a profound way. The first principle of coherence is closely related to appreciation for a system. The principle of homeostatic feedback loops concerns events that disturb the equilibrium of a system and is related to knowledge about variation. Neural plasticity is related to a theory of knowledge. The last two principles involve emotional and cognitive contributions to decision-making. They are closely related to the element psychology and one of them could lead to a further development of Deming’s system of profound knowledge.

Research limitations/implications

– The paper adds to the understanding of the role brain integration has for success in quality management efforts. A limitation is that it is difficult to localise higher-order thinking in brain function. Nonetheless, the research is indicative and provocative as a window to stimulate research into the fundamental basis of quality management success.

Practical implications

– The findings provide a deeper understanding of profound knowledge in quality management through relating it to how the brain is functioning, which is of value for quality managers and leaders striving for excellence for their organisations.

Originality/value

– The connection of brain principles with Deming’s profound knowledge has not been elaborated in the literature before.
A framework for VSM integrated with Fuzzy QFD
Authors: Mohanraj R. , Sakthivel M. , Vinodh S , Vimal K.E.K.
Published: August 2015

Purpose

– The purpose of this paper is to apply a framework for value stream mapping (VSM) integrated with fuzzy quality function deployment (QFD) for enabling scientific prioritization of improvement proposals to improve leanness.

Design/methodology/approach

– The literature was reviewed from the perspectives of VSM, QFD and fuzzy logic applications. The current state map was developed for the case component; fuzzy QFD was used for prioritizing improvement proposals and prioritized proposals were incorporated in the future state map.

Findings

– The approach enabled the scientific mapping of wastes with improvement proposals and thereby enabling systematic implementation of improvement proposals. The conducted pilot study resulted in 4 percent reduction in cycle time. As the lean implementation is a continuous process, furthermore improvements are expected in near future.

Research limitations/implications

– The study was conducted in an Indian camshaft manufacturing organization. The improvements in terms of leanness parameters were quantified.

Practical implications

– The findings determined from the study has practical relevance. Besides, managerial implications were also discussed.

Originality/value

– The study presented in this paper was conducted in a real time manufacturing environment. Hence the contributions of study are found to be valuable among academic and practicing communities.