bluuebunny/crossref_metadata_2025 huggingface dataset:
Exogenous Hydrogen Sulfide Alleviates-Induced Intracellular
Inflammation in HepG2 Cells
Authors: Wang Ya-Di , Li Jiao-Yang , Qin Yu , Liu Qiong , Liao Zhe-Zhen , Xiao Xin-Hua
Published: October 2019

Fatty acids induced hepatic inflammation plays an important role in
nonalcoholic fatty liver disease (NAFLD) pathogenesis. Hydrogen sulfide
(H2S), an endogenous gasotransmitter, has been established to
possess potent anti-inflammation in various human organs. However, the
anti-inflammation property of H2S in the fatty liver is still
needed to further elucidate. Hence, this study aimed to investigate whether
exogenous H2S can protect hepatocytes against inﬂammation
induced by palmitic acid (PA). HepG2 hepatocytes were exposed to PA for
24 h to induce free fatty acids-induced inflammation. The cells were
pretreated with NaHS (a donor of H2S) before exposure to PA. Cell viability,
inflammatory cytokines (TNF-α, IL-6 and IL-1β), NLRP3
inflammasome and NF-κB were measured by a combination of MTT assay,
ELISA, Western blot and Immunofluorescence. Here, we found that exogenous
H2S dose-dependently inhibited the expression of
pro-inflammatory cytokines, NLRP3 inflammasome and activation of
NF-κB signaling in PA-induced HepG2 cells. Thus, H2S
might be a candidate therapeutic agent against NAFLD.
Evaluation of Threaded External Skeletal Fixation Pin Insertion with and without Predrilling in Avian Bone
Authors: Lam Griselda , Nelson Jacqueline Tai Li , Wei Feng , Kim Sun-Young
Published: October 2019

Objective The aim of this study was to document the effects of positive-profile threaded external skeletal fixation (ESF) pin insertion without predrilling on heat generation, structural damage and pullout strength in avian bone than that with predrilling.

Study design This study was an ex vivo study.

Materials and Methods Twenty paired tibiotarsi and 40 paired humeri from 20 Mallard duck cadavers were used. Specimens were randomized to have positive-profile threaded ESF pins placed with or without predrilling insertion sites. Heat generation (maximum—baseline temperature) was measured during drilling and pin insertion with infrared thermography. Structural damage (gross trans-cortical damage and thread quality) was evaluated and scored using a visual analog scale (VAS). Mechanical testing was performed to evaluate pullout strength of inserted pins.

Results VAS scores for trans-cortical surfaces were significantly higher than for cis-cortical surfaces; however, no difference was noted between predrilled and non-predrilled specimens. No significant difference in heat generation or pullout strength was noted between pins placed with and without predrilling.

Conclusion Pin insertion without predrilling in avian humeri and tibiotarsi does not cause significantly more structural damage or heat generation, or reduced pullout strength, compared with predrilling. Overall, our results indicate that predrilling prior to ESF pin placement provides no obvious advantage in avian bone.
Platelets as Central Actors in Thrombosis—Reprising an Old Role and Defining a New Character
Authors: Stevens Hannah , McFadyen James D.
Published: October 2019

Platelets have long been considered simple anucleate cells that rapidly adhere and aggregate at sites of vascular injury. However, recent in vivo experimental data have shed new light on the platelet response to vascular injury. These data have unexpectedly revealed that platelet thrombus formation is a highly dynamic process and yields a platelet thrombus with a distinct hierarchical structure composed of a “core” of highly activated platelets and a “shell” of platelets in a low activation state. This has given rise to the concept that therapeutic targeting of the propagating thrombus shell may hold promise as a means to target thrombosis while sparing hemostasis. While platelets have been historically considered central to arterial thrombosis, they have been traditionally viewed as minor contributors to the formation of venous thrombosis. However, this concept has recently been challenged with the emergence of a large body of evidence highlighting the important proinflammatory function of platelets. The proinflammatory function of platelets is afforded by their ability to induce neutrophil extracellular trap formation, enhance leucocyte recruitment, and secrete granular contents such as high mobility group protein B1 and polyphosphate. These proinflammatory processes trigger coagulation, via the intrinsic pathway, and are central to the formation of venous thrombosis, a condition now appreciated to be a form of sterile inflammation. These data now place platelets at the center stage in orchestrating the thromboinflammatory response underpinning venous thrombosis and have provided new hope that novel platelet-targeted therapeutics may represent a safe and effective approach to prevent venous thrombosis.
Speaking of trauma: the race talk, the gun violence talk, and the racialization of gun trauma
Authors: Armstrong Madison , Carlson Jennifer
Published: October 2019

This paper considers the intersection of race and gun violence through the lens of trauma. We focus on two high-profile cases of gun violence: the state-deemed justifiable homicide of Trayvon Martin in Sanford, Florida, on February 26, 2012 and the active shooting that took place at Marjory Stoneman Douglas High School in Parkland, Florida, on February 14, 2018. These cases illustrate not just how people in the US experience gun violence in racially divergent ways (as existing literature suggests) but also how people—particularly parents—manage the anticipation of gun violence and its trauma. To this end, we develop the concept of “anticipatory trauma” and illustrate it by analyzing a set of social practices that have emerged surrounding gun violence: parents’ conversations with their children aimed at explaining and addressing their children’s unique risk of gun violence. Building on existing literature on “the Talk” among African American parents, we analyze a racial bifurcation in how parents talk about gun violence. Specifically, we detail “the Race Talk” (in relation to the Trayvon Martin case) and “the Gun Violence Talk” (in relation to the Parkland case), which differentially construct children’s vulnerability, the social phenomena that render them vulnerable, and the appropriate solutions for addressing that vulnerability. Without understanding anticipatory trauma as a racialized phenomenon, we risk leveling the gun violence debate—and creating gun policy that is neither politically meaningful nor practically effective for addressing the broad but complex issue of gun violence.
Superman vs. Nick O’Teen: anti-smoking campaigns and children in 1980s Britain
Authors: Mold Alex , Elizabeth Hannah
Published: October 2019

In December 1980, the Health Education Council launched a campaign designed to discourage children from taking up smoking. Advertisements on TV and in comics and magazines featured a battle between Superman and the evil Nick O’Teen as he attempted to recruit children to his army of smokers. Children were also encouraged to join Superman in his fight by signing a pledge not to smoke, in return for which they received a poster and badges featuring the superhero. This article examines the design, production, delivery and reception of the Superman vs. Nick O’Teen campaign in order to probe the multi-faceted nature of the making of healthy publics in 1980s Britain. Children constituted a particularly problematic public. On the one hand, they were thought to be vulnerable and easily led towards unhealthy lifestyle choices. But on the other, children were also recognised as agents who might convince adults, as well as their peers not to smoke. This ambivalent conceptualisation of the child as a potential victim of malign influences, or potential rational agent and force for good, is typical of the 1980s, a time when the meanings of the child as consumer, agent, and citizen were undergoing increased ideological debate. This campaign also took place as ideas about health education, its place within public health policy and practice, and its relationship with the public, were in flux. The battle between Superman and Nick O’Teen was thus not just about smoking, but about particular ways of seeing and interacting with healthy (and unhealthy) publics.
Electric-field effect on magnetic anisotropy of MgO/CoFe/capping structures
Authors: Zeng Minggang , Lourembam James , Lim Sze Ter
Published: October 2019

Using first-principles calculations, we investigate the magnetic anisotropy energy (MAE) controlled by applying an external electric field in MgO/CoFe/capping structures. The capping materials include Ta, Hf, Ir, Nb, and Ru. We find that capping materials can tune the magnetic anisotropy via the capping-dependent distribution of d-electrons near the Fermi level and the competition between orbital-related spin–orbit coupling. Moreover, we find that the voltage control of magnetic anisotropy efficiency (VCMAE) (η) of MgO/CoFe/capping structures is also correlated with capping-dependent zero-field d-orbital configuration. Ta, Ir, Nb, and Hf cappings have the η value of −179, −149, −119, and 387 fJ/V m, respectively. In addition, an η value as high as −894 fJ/V m can be achieved with Ru capping. Our work suggests that capping materials play a key role in tuning MAE, and Ru capping could be used to enhance the VCMAE for voltage-controlled magnetic random access memory.
Molecular-beam epitaxy of GaInSbBi alloys
Authors: Delorme O. , Cerutti L. , Luna E. , Trampert A. , Tournié E. , Rodriguez J.-B.
Published: October 2019

We have grown GaInSbBi single layers and GaInSbBi/GaSb multiquantum well (MQW) structures by molecular beam epitaxy. We observed that the addition of In strongly modifies and reduces the Bi incorporation into GaSb. For an In concentration of ∼3.7%, we reached a maximum Bi content of 10.5% while the highest Bi concentration falls to 3% with 10% of In. Additionally, droplets appear at lower Bi composition than in GaSbBi alloys. Finally, the optical properties of GaInSbBi/GaSb MQW structures were characterized by photoluminescence spectroscopy at room temperature. The longest emission wavelength observed was close to 2.6 μm for a composition of 10.5% and 3.7% of bismuth and indium, respectively.
Broad tunability of emission wavelength by strain coupled InAs/GaAs1 − xSbx quantum dot heterostructures
Authors: Saha Jhuma , Das Debabrata , Panda Debiprasad , Tongbram Binita , Chatterjee Arka , Liang Baolai , Gupta Kantimay Das , Pal Samir Kumar , Chakrabarti Subhananda
Published: October 2019

Tuning of the photoluminescence emission over a wider range of optical telecommunication wavelength (1.38 μm–1.68 μm) has been achieved by employing a GaAs1 − xSbx capping layer to the strain coupled bilayer InAs quantum dot (QD) heterostructures. It is shown that the modulation of strain between the two dot layers through variation in Sb-content and thickness of the capping layer strongly influence the dot size. The band alignment transformation from type-I to type-II is observed for high Sb-content in the capping layers. In addition, the carrier lifetime is improved by a factor of three in the QD heterostructures having type-II band alignment. This, we believe, is of importance for optoelectronic device applications.
Properties of THz coherent undulator radiation generated from a compact accelerator source at Kyoto University
Authors: Krainara Siriwan , Zen Heishun , Chatani Shuya , Kii Toshiteru , Ohgaki Hideaki
Published: October 2019

A compact accelerator-base source of THz Coherent Undulator Radiation (THz-CUR) at the Kyoto University has been developed with the purpose of providing intense quasimonochromatic and tunable THz-CUR at frequencies below 1 THz. The source is driven by a compact accelerator using a photocathode RF gun, which emits an electron beam with a fixed energy of 4.6 MeV and high bunch charge. The THz-CUR from our source can be generated when a compressed electron bunch passes through a planar undulator. In this study, we investigate the properties of this radiation, including the total radiation energy, spatial distribution, and power spectrum. With an electron beam of 160 pC bunch charge, the total radiation energy of THz-CUR at 0.16 THz was 1.2 µJ in the micropulse. The THz-CUR covering the frequency range from 0.16 THz to 0.65 THz could be produced by changing the magnetic field of the undulator at a 60 pC bunch charge. Due to the influence of the space charge forces causing the degradation of electron beam qualities, saturation of the radiation energy occurred, and the radiation power spectrum at a frequency of 0.65 THz could not be observed in the high charge condition (160 pC). The effects of bunch lengthening, energy spread, and emittance growth and the influence of the phase error on the generation of THz radiation are also discussed in this paper. This opens up the possibility of understanding the generation of THz-CUR and sheds further light on the enhancement of the radiation power.
Thermodynamic calculation and its experimental correlation with the growth process of boron arsenide single crystals
Authors: Ziyaee Hamidreza , Gamage Geethal Amila , Sun Haoran , Tian Fei , Ren Zhifeng
Published: October 2019

The reported high thermal conductivity of boron arsenide (BAs) has prompted scientists to characterize the various properties of this material. Thermodynamic data for the enthalpy (H), entropy (S), and Gibbs free energy (G) of BAs were previously predicted from theory. Here, its thermodynamic properties were determined from experimental measurements of its heat capacity (CP) over the temperature range of 298 to 1150 K and compared with the predicted data. The thermodynamic properties of BAs at 800 K were calculated to be H=−8.6kJmol−1, S=81.0Jmol−1K−1, and G=−73.4kJmol−1, and we found that its formation reaction becomes endothermic at 984 K. We also analyzed the experimental findings from growing a BAs single crystal (SC) by the chemical vapor transport (CVT) method. Thermodynamic concepts were applied to show that iodine is the most suitable transport agent among the halogens for obtaining BAs SC by CVT. Additionally, three different combinations of precursors were employed during BAs SC growth by CVT. The three approaches are described in terms of differences in partial pressure of a gaseous species, and their results are compared for possible optimization of the BAs SC growth process by CVT.
Revealing the structural and magnetic susceptibility aspects of Sr2+ substituted Y2−xSrxNiMnO6 (0 ≤ x ≤ 0.1) compounds
Authors: Pandey Devendra K. , Modi Anchit , Gaur N. K.
Published: October 2019

We have investigated the structural and magnetic properties of strontium (Sr2+) substituted polycrystalline doubly-ordered perovskite Y2−xSrxNiMnO6 (x = 0, 0.05, 0.1), characterized with X-ray diffraction, X-ray photoelectron spectroscopy, dc-magnetization, and frequency-dependent linear ac-susceptibility measurements. The undoped Y2NiMnO6 is observed with traces of YMnO3 and NiO as secondary phases, whereas the phase purity improved with Sr2+ substitution. The XRD patterns of Y2−xSrxNiMnO6 (x = 0, 0.05, 0.1) are fitted with the Rietveld refinement in a monoclinic (P21/n) space-group symmetry and the secondary phases YMnO3 and NiO are fitted in hexagonal (P63cm) and cubic (Fm3m) space groups, respectively. The structural modifications observed with Sr2+ substitution manifest in octahedral distortion, altered lattice parameters, average bond-length, bond angles, tolerance factor, and corresponding electron bandwidths. The XPS study confirms the presence of Jahn-Teller (JT-active) species (Ni3+, Mn3+) along with Ni2+, Mn4+ ions. Increasing Sr2+ concentration triggers the paramagnetic (PM) to ferromagnetic (FM) transition spontaneously, along with increased transition temperature (Tc). The thermomagnetic study in field cooled/zero-field cooled modes and linear ac-susceptibility measurements suggest that the investigated compounds exhibit nonspontaneous and cumulative magnetic domain-wall dynamics to attain FM-state with glassy-type behavior toward lower temperatures.
Contracting asymptotics of the linearized lapse-scalar field sub-system of the Einstein-scalar field equations
Authors: Ames Ellery , Beyer Florian , Isenberg James
Published: October 2019

We prove an asymptotic stability result for a linear coupled hyperbolic–elliptic system on a large class of singular background spacetimes in constant mean curvature gauge on the n-torus. At each spatial point, these background spacetimes are perturbations of Kasner-like solutions of the Einstein-scalar field equations which are not required to be close to the homogeneous and isotropic case. We establish the existence of a homeomorphism between Cauchy data for this system and a set of functions naturally associated with the asymptotics in the contracting direction, which we refer to as asymptotic data. This yields a complete characterization of the degrees of freedom of all solutions of this system in terms of their asymptotics. Spatial derivative terms can, in general, not be fully neglected which yields a clarification of the notion of asymptotic velocity term dominance.
Instability of nonlinear Trivelpiece-Gould waves. II. Weakly trapped particles
Authors: Dubin Daniel H. E.
Published: October 2019

This paper discusses a novel parametric instability mechanism caused by particles that are weakly trapped in the potential wells of a nonlinear “pump” wave. The pump wave is unstable to the growth of daughter waves with longer wavelength and nearly the same phase velocity as the pump. This induces adjacent potential peaks in the wave to slowly approach one-another, receding from other pairs of peaks. Particles that are weakly trapped between approaching peaks, with kinetic energies just below the potential maxima, are heated by compression and escape the well, and then become retrapped on the other side of the approaching peaks, where they amplify the compression by pushing the peaks together. The mechanism applies to low-collisionality plasmas supporting waves with near-acoustic dispersion relations such as ion sound waves, magnetized Langmuir waves, or Alfvén waves. The theory is compared to particle in cell simulations of Trivelpiece-Gould (TG) traveling waves, as well as to experiments on pure ion plasmas that observe parametric instability in TG standing waves.
Self-limited growth of an oxyhydroxide phase at the Fe3O4(001) surface in liquid and ambient pressure water
Authors: Kraushofer Florian , Mirabella Francesca , Xu Jian , Pavelec Jiří , Balajka Jan , Müllner Matthias , Resch Nikolaus , Jakub Zdeněk , Hulva Jan , Meier Matthias , Schmid Michael , Diebold Ulrike , Parkinson Gareth S.
Published: October 2019

Atomic-scale investigations of metal oxide surfaces exposed to aqueous environments are vital to understand degradation phenomena (e.g., dissolution and corrosion) as well as the performance of these materials in applications. Here, we utilize a new experimental setup for the ultrahigh vacuum-compatible dosing of liquids to explore the stability of the Fe3O4(001)-(√2 × √2)R45° surface following exposure to liquid and ambient pressure water. X-ray photoelectron spectroscopy and low-energy electron diffraction data show that extensive hydroxylation causes the surface to revert to a bulklike (1 × 1) termination. However, scanning tunneling microscopy (STM) images reveal a more complex situation, with the slow growth of an oxyhydroxide phase, which ultimately saturates at approximately 40% coverage. We conclude that the new material contains OH groups from dissociated water coordinated to Fe cations extracted from subsurface layers and that the surface passivates once the surface oxygen lattice is saturated with H because no further dissociation can take place. The resemblance of the STM images to those acquired in previous electrochemical STM studies leads us to believe that a similar structure exists at the solid-electrolyte interface during immersion at pH 7.
Effect of non-parallel mean flow on the acoustic spectrum of heated supersonic jets: Explanation of “jet quietening”
Authors: Afsar M. Z. , Sescu A. , Sassanis V.
Published: October 2019

Noise measurements of heated axisymmetric jets at a fixed supersonic acoustic Mach number indicate that the acoustic spectrum reduces when the temperature ratio increases. The “spectral quietening” effect has been observed both experimentally and computationally using large Eddy simulations. It was explained by Afsar, Goldstein, and Fagan [AIAA J. 49, 2522 (2011)] through the cancellation introduced by the enthalpy flux/momentum flux coupling term using the generalized acoustic analogy formulation. But the parallel flow assumption is known to give inaccurate predictions at high jet speeds. In this paper, we therefore extend the nonparallel flow asymptotic theory of Goldstein, Sescu, and Afsar [J. Fluid Mech. 695, 199 (2012)] for the vector Green’s function of the adjoint linearized Euler equations in the analogy. Using the steady Reynolds averaged Navier Stokes calculation for the jet mean flow, we find that the coupling term propagator is positive-definite and asymptotically subdominant at low frequencies corresponding to the peak jet noise when nonparallel flow effects are taken into account and self-consistent approximations for the turbulence structure are made. We then assess the validity of the non-parallel flow-based acoustic analogy model by computing the overall sound pressure level (OASPL) at various observation angles. Interpretation of the latter allows a more rational explanation of the quietening effect. In general, our noise predictions are in very good agreement with acoustic data beyond the peak frequency.
Probing the electronic structure of graphene near and far from the Fermi level via planar tunneling spectroscopy
Authors: Davenport John L. , Ge Zhehao , Liu Junyan , Nuñez-Lobato Carlos , Moon Seongphill , Lu Zhengguang , Quezada-Lopez Eberth A. , Hellier Kaitlin , LaBarre Patrick G. , Taniguchi Takashi , Watanabe Kenji , Carter Sue , Ramirez Arthur P. , Smirnov Dmitry , Velasco Jairo
Published: October 2019

Scanning tunneling spectroscopy (STS) has yielded significant insight into the electronic structure of graphene and other two-dimensional (2D) materials. STS directly measures a fundamental and directly calculable quantity: single particle density of states (SPDOS). Due to experimental setup limitations, however, STS has been unable to explore 2D materials in ultrahigh magnetic fields where electron-electron interactions can drastically change the SPDOS. Recent developments in the assembly of heterostructures composed of graphene and hexagonal boron nitride have enabled a device-based alternative to potentially overcome these roadblocks. Thus far, however, these nascent efforts are incomplete in analyzing and understanding tunneling spectra and have yet to explore graphene at high magnetic fields. Here, we report an experiment at magnetic fields up to 18 T, which uses graphene tunneling field effect transistors (TFETs) to establish a clear benchmark for the measurement and analysis of graphene planar tunneling spectroscopy. We acquire gate tunable tunneling spectra of graphene and then use these data and electrostatic arguments to develop a systematic analysis scheme. This analysis reveals that TFET devices directly probe electronic structure features near and far from the Fermi level. In particular, our study yields identification of the Dirac point and numerous Landau levels as they fill and empty with charge via the application of a gate voltage. Our work demonstrates that TFET devices are a viable platform for directly probing the electronic structure of graphene and other 2D materials in high magnetic fields, where exotic electronic states emerge.
Electrical transport properties of Ni-doped diamond-like carbon films at and above room temperature
Authors: Saha S. , Das A. K. , Hatada R. , Ensinger W. , Flege S. , Baba K. , Meikap A. K.
Published: October 2019

The dielectric constant, impedance spectroscopy, ac conductivity, and dc conductivity of Ni-doped diamond-like carbon (DLC) films are reported within a wide temperature and frequency window. The dc conductivity increases with temperature, possessing different activation regions. At higher temperatures, a reversible semiconductor to metal transition is observed in the doped samples. Both the ac and dc conductivities are observed to increase with Ni doping concentration. However, the dc self-bias plays an important role in conductivity. The ac conductivity follows Jonscher's power law. The frequency exponent study shows that the ac conduction is governed by the correlated barrier hopping model. The grain boundary resistance is found to be higher than the grain resistance. According to the electric modulus study, the undoped DLC deviates from the ideal Debye behavior, with the deviation being higher in the high-frequency region. The current-voltage characteristics show a nonlinear hysteresis behavior.
Large-scale parallel electric fields and return currents in a global simulation model
Authors: Arnold H. , Drake J. F. , Swisdak M. , Dahlin J.
Published: October 2019

A new computational model, kglobal, is being developed to explore energetic electron production via magnetic reconnection in macroscale systems. The model is based on the discovery that the production of energetic electrons during reconnection is controlled by Fermi reflection in large-scale magnetic fields and not by parallel electric fields localized in kinetic scale boundary layers. Thus, the model eliminates these boundary layers. However, although the parallel electric fields that develop around the magnetic x-line and associated separatrices are not important in producing energetic electrons, there is a large scale electric field that kickstarts the heating of low-energy electrons and drives the cold-electron return current that accompanies escaping energetic electrons in open systems. This macroscale electric field is produced by magnetic-field-aligned gradients in the electron pressure. We have upgraded kglobal to include this large-scale electric field while maintaining energy conservation. The new model is tested by exploring the dynamics of electron acoustic modes which develop as a consequence of the presence of two electron species: hot kinetic and cold fluid electrons. Remarkably, the damping of electron acoustic modes is accurately captured by kglobal. Additionally, it has been established that kglobal correctly describes the dynamics of the interaction of the parallel electric field with escaping hot electrons through benchmarking simulations with the Particle-In-Cell code p3d.
Acoustothermal heating in surface acoustic wave driven microchannel flow
Authors: Das Pradipta Kr. , Snider Arthur D. , Bhethanabotla Venkat R.
Published: October 2019

Surface acoustic wave (SAW) is a well-proven tweezer serving various applications such as particle manipulation, cell trapping and separations, fluid mixing, and biosensing. SAWs can cause significant heat generation due to acoustothermal heating as established experimentally. Theoretical understanding of acoustothermal heating is limited, primarily due to the difficulties presented by multiple time scales inherent in this phenomenon. We present a theoretical model based on a multiple scale perturbation approach to solve the fluid flow and heat transfer equations for SAW-driven acoustothermal heating of a Newtonian fluid in a microchannel. The first order fields are oscillatory with the same frequency as that of the SAW, whereas the second order components are time-averaged to account for the mean flow and temperature fields. We find that the temperature rise depends solely on the acoustic energy density and its conversion into internal energy via pressure work on the fluid and hydrodynamic transportation of heat. For a fixed aspect ratio, an increase in system size essentially increases the conversion of acoustic energy into internal energy, leading to an increase in temperature rise. On the other hand, an increase in SAW frequency for a given system size causes the acoustic energy density to increase and thereby increases the temperature rise. Temperature rise is found to increase linearly with SAW power, in agreement with experimental results reported in the literature. The quantitative model for the temperature field presented in this work will find applications in designing biosensors, microreactors, and in other SAW driven controllable digital microfluidic heating applications.
Shear thickening of dense suspensions: The role of friction
Authors: Sivadasan Vishnu , Lorenz Eric , Hoekstra Alfons G. , Bonn Daniel
Published: October 2019

Shear thickening of particle suspensions is caused by a transition between lubricated and frictional contacts between the particles. Using three-dimensional (3D) numerical simulations, we study how the interparticle friction coefficient (μm) influences the effective macroscopic friction coefficient (μ) and hence the microstructure and rheology of dense shear thickening suspensions. We propose expressions for μ in terms of distance to jamming for varying shear stresses and μm values. We find μ to be rather insensitive to interparticle friction, which is perhaps surprising but agrees with recent theory and experiments. Unifying behaviors were observed between the average coordination numbers of particles across a wide range of viscous numbers and μm values.
Experimental study of elevation- and depression-type internal solitary waves generated by gravity collapse
Authors: Du Hui , Wei Gang , Wang Shao-Dong , Wang Xin-Long
Published: October 2019

Gravity collapse in density stratified fluids can excite internal solitary waves (ISWs), which have been studied by creating initial steplike rectangular disturbances in two-layer fluid systems in stratified fluid flumes. The observation of the elevation- and depression-type ISWs has brought detailed insights into the conditions that generate stable propagation of ISWs and the properties thereof. In this work, the results of such experiments are compared with the wave profile, phase velocity, characteristic frequency, and induced flow velocity calculated by using nonlinear theories. In addition, we analyze the capacity of nonlinear theories to accurately predict the characteristics of stable ISWs generated by gravity collapse. The results show that ISWs are generated by the evolution of the propagating vortex that develops from the vertical shear movement in the mixed-density region of the fluid. The length L and depth D of the initial steplike disturbance and the upper- and lower-layer thicknesses h1 and h2 together determine the amplitude, number, and propagation state of the ISWs that are generated. For small-amplitude elevation- and depression-type ISWs (|a/H| < 0.04, where a and H are the amplitude and total depth of the stratified fluid, respectively), the generated ISWs are consistent with the Korteweg de Vries (KdV) theory. Large-amplitude ISWs, however, tend to be consistent with the extended KdV (eKdV) or Miyata–Choi–Camassa (MCC) theories. For larger (smaller) differences |h2 − h1|, the MCC (eKdV) theory provides the best prediction of large-amplitude ISWs.
A phenomenological scheme for reversed quartet mechanism of electron spin polarization in covalently linked systems of chromophore and free radical: Determination of magnitude of polarization and application to pyrene–TEMPO linked molecules
Authors: Tripathi Alok Kumar , Rane Vinayak , Kundu Sushma , Das Ranjan
Published: October 2019

Generation of electron spin polarization (ESP) during the bimolecular quenching of an excited chromophore by a free radical is generally explained by the radical–triplet pair mechanism, which is capable of giving the magnitudes of ESP arising from the quenching of the singlet or the triplet excited chromophore. When the chromophore and the free radical are covalently linked, although there are several mechanisms to explain the observed spin-polarized electron paramagnetic resonance signals under a variety of experimental conditions and in different chromophore–radical systems, there are no schemes that allow quantitative determination of the magnitude of ESP. In this work, we present a phenomenological scheme with this objective. In this scheme, we have incorporated several concepts of the reversed quartet mechanism of Rozenshtein et al. [J. Phys. Chem. A 109, 11144 (2005)] to our phenomenological sequential quenching scheme [V. Rane and R. Das, J. Phys. Chem. A 119, 5515 (2015)] of ESP in covalently linked chromophore–radical systems. This phenomenological reversed quartet scheme is able to explain the observed inversion of ESP with time and can also give a quantitative measure of the absorptive and emissive ESP in such systems. We have applied this scheme to the photophysical quenching of a series of newly synthesized pyrene–TEMPO molecules, where a spacer group of different lengths covalently links the pyrene chromophore and the TEMPO free radical. Given the simplicity of our scheme, reasonable estimates of the magnitudes of the ESP have been obtained in all cases.
Influence of Sodium Dodecyl Sulfate on the Microstructure and Electrochromic Performance of an Electrodeposited Nickel Oxide Film
Authors: Mao Junda , Duan Xiang , Yao Aihua
Published: October 2019

Nickel oxide (NiO) films were deposited on indium tin oxide (ITO) coated glass substrates using a potentiostatic electrodeposition method from Ni(NO3)2 aqueous solution containing the surfactant sodium dodecyl sulfate (SDS). The microstructure, morphology, and electrochromic performance of the NiO films were investigated. Our results showed that the addition of SDS inhibited the growth of NiO crystals, tailored the morphology of the films, and favoured their electrochromic performance. The NiO films deposited in the presence of 6mM SDS exhibited excellent electrochromic performance in OH− containing electrolytes (0.1M KOH), with a high optical contrast of over 77% at 550nm, short switching time (5.62s for bleaching and 7.34s for coloration), and enhanced cycling durability.
The expression pattern of the Pho1a genes encoding plastidic starch phosphorylase correlates with the degradation of starch during fruit ripening in green-fruited and red-fruited tomato species
Authors: Slugina Maria A. , Shchennikova Anna V. , Kochieva Elena Z.
Published: October 2019

Genes encoding plastidic starch phosphorylase Pho1a were identified in 10 tomato species (Solanum section Lycopersicon). Pho1a genes showed higher variability in green-fruited than in red-fruited tomato species, but had an extremely low polymorphism level compared with other carbohydrate metabolism genes and an unusually low ratio of intron to exon single nucleotide polymorphisms (SNPs). In red-fruited species, Pho1a was expressed in all analysed tissues, including fruit at different developmental stages, with the highest level in mature green fruit, which is strong sink organ importing sucrose and accumulating starch. In green-fruited species Solanum peruvianum and Solanum arcanum, the Pho1a expression level was similar in mature green and ripe fruit, whereas in Solanum chmielewskii, it was higher in ripe fruit, and in Solanum habrochaites, the dynamics of fruit-specific Pho1a expression was similar to that in red-fruited tomatoes. During fruit development, in red-fruited Solanum lycopersicum, sucrose level was low, the monosaccharide content increased; in green-fruited S. peruvianum, the sucrose concentration increased and those of monosaccharides decreased. In both species, the starch content and Pho1a expression were downregulated. The evolutionary topology based on Pho1a sequences was consistent with the current division of tomatoes into red-fruited and green-fruited species, except for S. habrochaites.
The contribution of duff consumption to fire emissions and air pollution of the Rough Ridge Fire
Authors: Zhao Fengjun , Liu Yongqiang , Goodrick Scott , Hornsby Benjamin , Schardt Jeffrey
Published: October 2019

It is typically difficult to burn duff because of high fuel moisture; however, under persistent drought conditions, duff will burn readily. This study investigates the burning of a deep duff layer by the 2016 Rough Ridge Fire, in the southern United States, under drought conditions and evaluates the contribution of duff consumption to fire emissions and air pollution. Fuel loading was measured and used to evaluate the BlueSky framework. Smoke was simulated for three fuel loading and moisture scenarios of field measurement, BlueSky estimated fuel loading, and a hypothetical moist condition. The measured fuels had a very deep duff layer that had accumulated over decades due to the lack of historical fires, most of which was burned by the fire. The burning of this deep duff layer contributed substantially to the increased fire emissions at the fire site and the air pollution in metro Atlanta. In contrast, BlueSky under-predicted duff loading and fire emissions. As a result, no major air pollution episodes were predicted for metro Atlanta. The high-moisture scenario also failed to produce a major air-pollution episode within Atlanta, which highlights the contribution of the drought to the air-pollution episode within Atlanta.
Definitions, methods, and applications in interpretable machine learning
Authors: Murdoch W. James , Singh Chandan , Kumbier Karl , Abbasi-Asl Reza , Yu Bin
Published: October 2019

Significance

The recent surge in interpretability research has led to confusion on numerous fronts. In particular, it is unclear what it means to be interpretable and how to select, evaluate, or even discuss methods for producing interpretations of machine-learning models. We aim to clarify these concerns by defining interpretable machine learning and constructing a unifying framework for existing methods which highlights the underappreciated role played by human audiences. Within this framework, methods are organized into 2 classes: model based and post hoc. To provide guidance in selecting and evaluating interpretation methods, we introduce 3 desiderata: predictive accuracy, descriptive accuracy, and relevancy. Using our framework, we review existing work, grounded in real-world studies which exemplify our desiderata, and suggest directions for future work.
Conspicuous fabrications
Authors: Kraatila Elise
Published: October 2019

It has become an increasingly common suggestion that we are currently living in a ‘post-truth’ world, where
compelling storytelling has usurped the place of empirical facts in determining our shared social reality. The impression of
reality becoming endlessly mutable by storytelling is bolstered by the idea of narratives as mediators of human experience,
developed across humanities and social sciences, becoming part of a popularized post-truth discourse. In this discourse, stories
are viewed as tools for constructing the world, and attributed power to create their own truths. I argue that the challenge for
meaningful communication posed by this sentiment can be uniquely and effectively confronted in speculative storytelling, and
especially currently enormously popular fantasy fiction. By creating thought experiments in conspicuously fabricated settings,
fantasy stories highlight storytelling as a means for coming to terms with different realities – and provide their audiences with
tools for critically examining and challenging the post-truth discourse.
“I can tell the difference between fiction and reality”
Authors: Browse Sam , Hatavara Mari
Published: October 2019

This article approaches fictionality as a set of semiotic strategies prototypically associated with fictional forms of storytelling (Hatavara & Mildorf, 2017b). Whilst these strategies are strongly associated with fiction, they might also be used in non-fictional and ontologically ambivalent contexts to create ‘cross-fictional’ rhetorical effects. We focus on the representation of thought and consciousness. Using the concept of ‘mind style’ (Fowler, 1977,1996;Leech & Short, 1981;Semino, 2007), we investigate the linguistic representation of the internal monologue of British Prime Minister, Theresa May, in a satirical newspaper article. The stylistic analysis of the PM’s mind style facilitates an account of the elaborate and nuanced mixing of May and the author’s ideological perspectives throughout the piece. We argue that this cross-fictional, stylistic approach better accounts for the satirical effects of fictionality in the text than those placing a premium on authorial intention and the invented nature of the narrative discourse.
The rhetoric of factuality in narrative
Authors: Björninen Samuli
Published: October 2019

The article presents a method for studying the factuality of narrative as a rhetoric. The need for such a method is apparent in the so-called post-truth climate, which sees us witnessing debates about semantic chimeras like “alternative facts” and “fake news.” The article arrives at its method by tackling challenges arising both in narrative theory and in fictionality studies. This involves developing models that let us take into account both the effects of local discursive features and the “macrogeneric” and “generic” frames guiding expectations about how communication is meant to work. The method is used in analysis of one of the controversial stories by the journalist Claas Relotius, who is currently being investigated in the forgery scandal of the magazineDer Spiegel.
Coral bioerosion on the marginal reefs of northeastern Arabia
Authors: Al-Mansoori Noura , McParland Dain , Howells Emily , Bauman Andrew , Burt John A.
Published: October 2019

The maintenance of coral reef framework results from a balance between skeletal accretion and bioerosion, and this balance can be disrupted by environmental stress and disturbance. Coral reefs in northeastern Arabia exist in extreme environmental conditions and have experienced severe disturbances in recent years. This study assessed the intensity of macrobioerosion in two regionally common species, Platygyra daedalea and Cyphastrea microphthalma, at three sites within the southern Persian/Arabian Gulf and at one site in the Sea of Oman. On average, bioeroders removed 9.2 ± 1.6% of the skeletal surface area in P. daedalea and 26.4 ± 1.6% in C. microphthalma, with variation between species attributed to differences in colony morphology. Bioerosion intensity varied among sites in each species. Within the southern Arabian Gulf, both P. daedalea and C. microphthalma showed the highest bioerosion intensity at Delma, in the western region, compared with that of Saadiyat or Ras Ghanada to the east, with the elevated bioerosion at Delma consistent with a history of more extreme environmental conditions and bleaching-related disturbances. The highest bioerosion in P. daedalea occurred at Fujairah in the Sea of Oman, and this site was amongst the highest in C. microphthalma. Although this site is characterized by more benign environmental conditions, reefs in this area experienced mass coral mortality due to anoxia during a large-scale harmful algal bloom in 2008/9 and the high bioerosion in Fujairah likely represents a long-term signature of this disturbance. The intensity of macrobioerosion observed here is high compared with other regions, suggesting that that chronic exposure to long-term environmental stress and a history of disturbance may lead enhanced loss of reef framework.
A channel profile report of the unusual K+ channel KtrB
Authors: Mikušević Vedrana , Schrecker Marina , Kolesova Natalie , Patiño-Ruiz Miyer , Fendler Klaus , Hänelt Inga
Published: October 2019

KtrAB is a key player in bacterial K+ uptake required for K+ homeostasis and osmoadaptation. The system is unique in structure and function. It consists of the K+-translocating channel subunit KtrB, which forms a dimer in the membrane, and the soluble regulatory subunit KtrA, which attaches to the cytoplasmic side of the dimer as an octameric ring conferring Na+ and ATP dependency to the system. Unlike most K+ channels, KtrB lacks the highly conserved T(X)GYG selectivity filter sequence. Instead, only a single glycine residue is found in each pore loop, which raises the question of how selective the ion channel is. Here, we characterized the KtrB subunit from the Gram-negative pathogen Vibrio alginolyticus by isothermal titration calorimetry, solid-supported membrane–based electrophysiology, whole-cell K+ uptake, and ACMA-based transport assays. We found that, despite its simple selectivity filter, KtrB selectively binds K+ with micromolar affinity. Rb+ and Cs+ bind with millimolar affinities. However, only K+ and the poorly binding Na+ are efficiently translocated, based on size exclusion by the gating loop. Importantly, the physiologically required K+ over Na+ selectivity is provided by the channel’s high affinity for potassium, which interestingly results from the presence of the sodium ions themselves. In the presence of the KtrA subunit, sodium ions further decrease the Michaelis–Menten constant for K+ uptake from milli- to micromolar concentrations and increase the Vmax, suggesting that Na+ also facilitates channel gating. In conclusion, high binding affinity and facilitated K+ gating allow KtrAB to function as a selective K+ channel.
A new paradigm for the dynamics of the early Universe
Authors: Tucker R W , Walton T J , Arrayás M , Trueba J L
Published: October 2019

This paper invokes a new mechanism for reducing a coupled system of fields (including Einstein’s equations without a cosmological constant) to equations that possess solutions exhibiting characteristics of immediate relevance to current observational astronomy.

Our approach is formulated as a classical Einstein-vector-scalar-Maxwell-fluid field theory on a spacetime with three-sphere spatial sections. Analytic cosmological solutions are found using local charts familiar from standard LFRW cosmological models. These solutions can be used to describe different types of evolution for the metric scale factor, the Hubble, jerk and de-acceleration functions, the scalar spacetime curvature and the Kretschmann invariant constructed from the Riemann–Christoffel spacetime curvature tensor. The cosmological sector of the theory accommodates a particular single big-bang scenario followed by an eternal exponential acceleration of the scale factor. Such a solution does not require an externally prescribed fluid equation of state and leads to a number of new predictions including a current value of the ‘jerk’ parameter, ‘Hopfian-like’ source-free Maxwell field configurations with magnetic helicity and distributional ‘bi-polar’ solutions exhibiting a new charge conjugation symmetry.

An approximate scheme for field perturbations about this particular cosmology is explored and its consequences for a thermalisation process and a thermal history are derived, leading to a prediction of the time interval between the big-bang and the decoupling era. Finally it is shown that field couplings exist where both vector and scalar localised linearised perturbations exhibit dispersive wave-packet behaviours. The scalar perturbation may also give rise to Yukawa solutions associated with a massive Klein–Gordon particle. It is argued that the vector and scalar fields may offer candidates for ‘dark-energy’ and ‘dark-matter’ respectively.