bluuebunny/crossref_metadata_2025 huggingface dataset:
Brønsted Acids of Anionic Chiral Cobalt(III) Complexes as Catalysts for the Iodoglycosylation or Iodocarboxylation of Glycals
Authors: Wang Rui , Wu Wen-Qiang , Li Na , Shen Jia , Liu Kun , Yu Jie
Published: April 2019

Brønsted acids of anionic chiral Co(III) complexes were found to act as efficient phase-transfer catalysts for the diastereoselective iodoglycosylation or iodocarboxylation of glycals with a variety of alcohols or carboxylic acids, respectively, with N-iodosuccinimide as the iodo cation source. The corresponding 2-deoxy-2-iodoglycosides, including monosaccharides and disaccharides, and 2-deoxy-2-iodoglycosyl carboxylates, which are of high synthetic and biological importance, were obtained in high yields (up to 88%) with good diastereoselectivities (up to 9:1 dr).
Decentring antibiotics: UK responses to the diseases of intensive pig production (ca. 1925-65)
Authors: Woods Abigail
Published: April 2019

It is widely assumed that the development of antibiotics had a transformative effect on livestock production by making it possible to keep larger numbers of animals in smaller spaces without them succumbing to disease. Using the health and production of UK pigs, ca. 1925-65, as a case study, this article argues that their impact has been overstated. It draws on evidence from veterinary journals, farming magazines, and government-appointed committees to demonstrate the significance of other methods of countering the diseases that emerged in association with intensive production systems. Devised by vets, farmers and other experts, these methods predated antibiotics and evolved alongside them. They were rooted in a shared understanding of pig diseases as highly complex phenomena that resulted from interactions between pig bodies and their environments. Recognition of the roles played by housing, husbandry, nutrition, and pathogens in the production of pig disease suggested multiple possible points of intervention. In situating antibiotics within this landscape of disease prevention and control, this article challenges existing claims about their reception and impact, decentres them from the history of intensive farming, and draws attention to other methods of promoting pig health, which may find renewed applications as we move towards a post-antibiotic era.
Electronic energy transfer studied by many-body Green’s function theory
Authors: Leng Xia , Jin Fan , Wei Min , Ma Huizhong , Feng Jin , Ma Yuchen
Published: April 2019

We present a combination of many-body Green’s function theory and Förster-Dexter theory to estimate the excitation energy transfer (EET) coupling in both the isolated and condensed systems. This approach employs the accurate wave functions of excitons, which are derived from the Bethe-Salpeter equation, in the donor and acceptor to set up the electronic coupling terms. Dexter coupling, which arises from the exchange-correlation effect, is evaluated based on the GW method which is a state-of-the-art ab initio theory for the description of self-energy. This approach is applicable to various situations, especially for periodic systems. The approach is tested on some model molecular dimers and compared with other high-level quantum chemistry methods together with the exact supermolecule scheme. Finally, we apply it to study the EET between periodic single-walled carbon nanotubes, exploring the dependence of EET on the chirality of nanotubes and the type of excitation transferred, finding that dark states play key roles in the EET between nanotubes. The EET rate falls as ∼D−12 approximately with the distance D between nanotubes for small D, much faster than the traditional Förster model.
Comment on “An ultrathin and broadband metamaterial absorber using multi-layer structures” [J. Appl. Phys. 114, 064109 (2013)]
Authors: Wahidi M. S. , Mustafa Meraj-E- , Tahir Farooq A.
Published: April 2019

In a recent publication by Xiong et al. [J. Appl. Phys. 114, 064109 (2013)], a linear cross-polarizer is erroneously interpreted as a broadband absorber with a claimed absorptivity above 90% over a frequency range of 8.3721 GHz. In this article, the authors have presented an investigative study demonstrating that the structure proposed by Xiong et al. is actually an efficient cross-polarizer rather than a perfect absorber. If we consider both co- and cross-polarized components of the reflected electromagnetic wave, the subject absorber provides less than 20% absorption in the claimed band. In addition, the polarization conversion ratio of the structure is above 85% within the operating band, this makes the subject metasurface a potential candidate for applications where high-efficiency cross-polarization is desired.
Incorporating aligned carbon nanotube electrode arrays in organic thin-film transistors
Authors: Yi Zhihui , Sayago Jonathan
Published: April 2019

We introduce a very simple technique to obtain aligned carbon nanotube arrays tested in organic thin-film transistors based on poly[2-methoxy-5-(2-ethylhexyloxy)-1,4-phenylenevinylene] (MEH-PPV) as the organic semiconductor. The technique to prepare aligned CNT electrode arrays was simple and resulted in organic thin-film transistors with a higher drain-source current and lower threshold voltage proving their effectiveness as injection electrodes. We believe that the aligned carbon nanotube electrode array can find important applications in organic microelectronic and biosensor devices.
Radial planetary vorticity tilting in the leading-edge vortex of revolving wings
Authors: Werner Nathaniel H. , Chung Hojae , Wang Junshi , Liu Geng , Cimbala John M. , Dong Haibo , Cheng Bo
Published: April 2019

Previous studies suggested that Coriolis acceleration and spanwise flow both played key roles in stabilizing the leading-edge vortex (LEV) in revolving wings. The current study examined a mechanism that relates the effects of Coriolis acceleration, spanwise flow, and the tilting of the planetary vorticity on removing the radial component of LEV vorticity. Specifically, the fluid particles moving with the spanwise flow toward the wing tip are expected to experience tangential Coriolis acceleration in the wing-fixed rotating frame; therefore, a vertical gradient in spanwise flow can create a vertical gradient in the Coriolis acceleration, which will in turn produce oppositely signed radial vorticity within the LEV. This gradient of Coriolis acceleration corresponds to the radial component of planetary vorticity tilting (PVTr) that reorients the planetary vorticity into the spanwise (radial) direction, therefore producing oppositely signed radial vorticity. Using an in-house, immersed-boundary-method flow solver, this mechanism was investigated alongside the other vorticity dynamics for revolving wings of varying aspect ratio (AR = 3, 5, and 7) and Reynolds number (Re = 110 and 1400). Analyses of vorticity dynamics showed that the PVTr consistently produced oppositely signed vorticity for all values of AR and Re investigated, although other three-dimensional phenomena play a similar but more dominant role when Re = 1400. In addition, the relative strength of the PVTr increased with increasing AR due to a decrease in the magnitude of advection. Finally, a dimensional analysis was performed on the advection and PVTr for the different AR and Re.
Topological and geometrical quantities in active cellular structures
Authors: Wenzel D. , Praetorius S. , Voigt A.
Published: April 2019

Topological and geometrical properties and the associated topological defects find a rapidly growing interest in studying the interplay between mechanics and the collective behavior of cells on the tissue level. We here test if well studied equilibrium laws for polydisperse passive systems such as Lewis’ and Aboav-Weaire’s law are applicable also for active cellular structures. Large scale simulations, which are based on a multiphase field active polar gel model, indicate that these active cellular structures follow these laws. If the system is in a state of collective motion, quantitative agreement with typical values for passive systems is also observed. If this state has not developed, quantitative differences can be found. We further compare the model with discrete modeling approaches for cellular structures and show that essential properties, such as T1 transitions and rosettes, are naturally fulfilled.
Leap-frog transport of magnetically driven anisotropic colloidal rotors
Authors: Massana-Cid Helena , Navarro-Argemí Eloy , Levis Demian , Pagonabarraga Ignacio , Tierno Pietro
Published: April 2019

In this article, we combine experiments and theory to investigate the transport properties of anisotropic hematite colloidal rotors that dynamically assemble into translating clusters upon application of a rotating magnetic field. The applied field exerts a torque to the particles forcing rotation close to a surface and thus a net translational motion at a frequency tunable speed. When approaching, pairs of particles are observed to assemble into stable three-dimensional clusters that perform a periodic leap-frog type dynamics and propel at a faster speed. We analyze the cluster formation and its lifetime and investigate the role of particle shape in the propulsion speed and stability. We show that the dynamics of the system results from a delicate balance between magnetic dipolar interactions and hydrodynamics, and we introduce a theoretical model that qualitatively explains the observed phenomena.
Interparticle torques suppress motility-induced phase separation for rodlike particles
Authors: van Damme Robin , Rodenburg Jeroen , van Roij René , Dijkstra Marjolein
Published: April 2019

To study the role of torque in motility-induced phase separation (MIPS), we simulate a system of self-propelled particles whose shape varies smoothly from isotropic (disks/spheres) to weakly elongated (rods). We construct the phase diagrams of 2D active disks, 3D active spheres, and 2D/3D active rods of aspect ratio l/σ = 2. A stability analysis of the homogeneous isotropic phase allows us to predict the onset of MIPS based on the effective swimming speed and rotational diffusion of the particles. Both methods find suppression of MIPS as the particle shape is elongated. We propose a suppression mechanism based on the duration of collisions and argue that this mechanism can explain both the suppression of MIPS found here for rodlike particles and the enhancement of MIPS found for particles with Vicsek interactions.
Satellite-augmented diffuse solar radiation separation models
Authors: Yang Dazhi , Boland John
Published: April 2019

Separation models predict diffuse horizontal irradiance from other meteorological parameters such as the global horizontal irradiance or zenith angle. From a mathematical point of view, the separation modeling problem is a regression, where the regressors are observed or computed variables and the regressand is the unobserved diffuse fraction. The most successful minute-resolution separation model prior to 2016 was proposed by Engerer, which is constructed using a trend component (cloud enhancement) and a main effect (logistic function). Subsequently, the Starke model published in 2018 further improved the Engerer model. It is herein shown that the logistic-function type of model, and many other separation models, can be transformed into a (condition-based) multiple linear regression problem. Under this transformation framework, two new models are proposed, which strictly dominate the performance of the Engerer model and the Starke model, at all 7 test sites across the continental United States, making them probably the most accurate separation models to date. The new models are also tested at 5 European sites with unseen data (i.e., not involved during model parameter fitting); their performance again dominates all benchmarking models. The new separation models leverage half-hourly satellite-derived diffuse fraction. Since satellite data are available globally, the satellite-augmented separation models have universal applicability. However, despite their good performance, empirical separation models suffer from a series of issues. Hence, models driven by atmospheric physics are the “true gems” that one should pursue.
Three-dimensional flow structures in X-shaped junctions: Effect of the Reynolds number and crossing angle
Authors: Correa P. G. , Mac Intyre J. R. , Gomba J. M. , Cachile M. A. , Hulin J. P. , Auradou H.
Published: April 2019

We study numerically the three-dimensional (3D) dynamics of two facing flows in an X-shaped junction of two circular channels crossing at an angle α. The distribution of the fluids in the junction and in the outlet channels is determined as a function of α and the Reynolds number Re. Our goal is to describe the different flow regimes in the junction and their dependence on α and Re. We also explore to which extent two-dimensional (2D) simulations are able to describe the flow within a 3D geometry. In the 3D case, at large Re’s (≳50) and α’s (≳60°), axial vorticity (i.e., parallel to the outlet axis) of magnitude increasing both with α and Re develops in the outlet channels and cannot be reproduced by 2D numerical simulations. At lower angles (α ≲ 60°), instead, a mean vorticity component perpendicular to the junction plane is present: both its magnitude and the number of the corresponding vortices (i.e., recirculation zones) increase as α decreases. These vortices appear in both 2D and 3D simulations but at different threshold values of α and Re. At very low Re’s (≲5) and α’s (∼15°), the flow structure in 3D simulations is nearly 2D but its quantitative characteristics differ from 2D simulations. As Re increases, this two-dimensionality disappears, while vortices due to flow separation appear in the outlet channels.
Glide of threading dislocations in (In)AlGaAs on Si induced by carrier recombination: Characteristics, mitigation, and filtering
Authors: Hughes Eamonn T. , Shah Rushabh D. , Mukherjee Kunal
Published: April 2019

III-V optoelectronics grown epitaxially on Si substrates have large networks of dislocations due to a lattice constant mismatch between the device layers and the substrate. Recombination-enhanced dislocation glide (REDG) allows these dislocations to move and increase in length during device operation, which degrades performance. In this paper, we study REDG dynamics of threading dislocations in situ in (In)AlGaAs double heterostructures grown on Si substrates using scanning electron microscopy cathodoluminescence. The driving force for REDG arises due to the coefficient of thermal expansion differences between Si and the III-V layers leading to large residual strains in the films. Tracking of threading dislocations as moving dark spot defects reveals glide characteristics that vary based on the nature of the dislocation. Remarkably, the alloying of a few atom percent of indium using metamorphic structures arrests threading dislocation glide by more than two orders of magnitude. Finally, we present REDG-based filtering as a pathway to reducing the threading dislocation density in select areas, removing a large fraction of the mobile dislocations. Together, these techniques will enable the understanding of dislocation–dislocation and carrier–dislocation interactions that have so far remained elusive during device operation, leading to reliable III-V integrated optoelectronics on silicon.
Realization of coalescence-induced condensate droplet jumping on a hierarchical porous superhydrophobic surface over a wide range of subcooling up to 20 K
Authors: Mou Lin-Wei , Zhang Tian-Yu , Zhang Jia-Yi , Li Jia-Qi , Fan Li-Wu
Published: April 2019

Coalescence-induced jumping of condensate droplets has been studied as an emerging mode for enhanced condensation heat transfer. However, the spontaneous droplet jumping phenomenon usually disappears at relatively higher degrees of subcooling due to the increase of nucleation density of condensate droplets. In this Letter, we show that self-propelled droplet jumping condensation can be realized surprisingly on a hierarchical porous superhydrophobic surface, having pores of the size of ∼20 μm with nanoscale dendritic structures, which was fabricated via a facile electrochemical deposition method. Droplet jumping condensation was always able to be sustained on this surface, making it never flooded even at elevated subcooling up to ∼20 K, although the intensity of droplet jumping degraded gradually with increasing the subcooling. It was hypothesized that the presence of microscale ridges among the pores, where nucleating droplets tended to appear and grow over the nano-structures on the ridge tips, serve as spatial separation barriers that prevent the surfaces from nucleation-density-modulated flooding at relatively high degrees of subcooling. As compared to conventional dropwise condensation on a smooth hydrophobic surface, significant heat transfer enhancement was able to attain for subcooling up to ∼7 K. The fabrication of this hierarchical porous superhydrophobic surface was deemed to be rapid, scalable, and highly-adaptive for curved surfaces on metallic bulk materials, e.g., copper tubes, with a great potential for industrial condensation applications.
Simulation of a concept for a compact ultrafast X-ray pulse source based on RF and THz technologies
Authors: Vinatier T. , Assmann R. W. , Dorda U. , Lemery F. , Marchetti B.
Published: April 2019

We study through simulations a layout mixing RF and THz technologies for a compact ultrafast X-ray pulse source based on Inverse Compton Scattering (ICS), aiming to deliver few femtoseconds to sub-femtosecond pulses. The layout consists of an S-band gun as the electron source and a dielectric-loaded circular waveguide driven by a multicycle THz pulse to accelerate and longitudinally compress the bunch, before X-ray generation via ICS with a laser pulse. We detail several schemes allowing the optimization of the electron bunch properties. This optimization leads to a preliminary layout and various working points able to deliver 0.1–5 pC bunches, ranging from 15 to 18 MeV average kinetic energy, 0.4 to 5 fs rms length, 0.1% to 2.6% rms energy spread, and 5 to 13 μm rms transverse size. Simultaneously, the beamline is kept compact (≈1.3 m up to the ICS point), which has not yet been achieved using only conventional RF technologies. The properties of the X-ray pulse are investigated with simulations, showing the possibility to tune its energy between 2.9 and 11.5 keV. For 400 mJ of laser energy, 1.5 × 104–7.7 × 104 photons/pulse in 1.5% rms bandwidth or 6.2 × 103–3.5 × 104 photons/pulse with lower bandwidths (0.56%–1.5% rms along the energy range) can be expected. The properties of the DLW and of the THz pulse driving it, the state-of-the-art of the THz pulse generation schemes, and the influence of various jitters and the limits that they should not exceed for a reasonably stable operation are finally given.
Analysis of rolling friction effects on oblique rebound by redefining tangential restitution and friction
Authors: Doménech-Carbó Antonio
Published: April 2019

The planar oblique impact of a homogeneous sphere on an infinitely massive rough plane is described assuming that normal and tangential restitution mechanisms operate independently of friction, and that frictional effects include not only the usual Coulomb model but also rolling friction effects. This formulation extends early models including rolling friction effects in the description of impact events to include the independent friction restitution closure. The model yields velocity-independent equations for postimpact linear and angular velocities in four impact regimes, namely, sliding plus rolling, sliding nonrolling, stick plus rolling, and stick nonrolling whose predictions are compared with experimental data from the literature.
Magneto-conductivity of tilted type-I Weyl semimetals with different types of impurities
Authors: Shao Jianmei , Yan Lijuan
Published: April 2019

We theoretically study the longitudinal magneto-conductivity of tilted type-I Weyl semimetals with three different types of impurities via a two-node model with opposite chirality and tilt vector. The Landau level solutions suggest that the Fermi velocity of the zeroth Landau level is dressed by the tilt and the angle between the magnetic field and the tilt direction. At low temperature and only considering the zeroth Landau level, we find that the magneto-conductivity σzz depends strongly on the tilt-dressed Fermi velocity and thus shows a strong angle dependence. This angle dependence of conductivity will be enhanced by the increase of the degree of tilt. Besides, the conductivity is very sensitive to impurities. σzz decreases with increasing impurity density and scattering strength, and it has different magnetic field dependence for different scattering potentials. For short-range delta scattering, it is independent of B. But for long-range random Gaussian potential and screened Coulomb potential, it may show a linear and quasi-quadratic dependence on B, respectively. These findings help us have a better understanding of the magneto-transport properties of the tilted type-I Weyl semimetals.
Unrestricted treatment for the direct variational determination of the two-electron reduced density matrix for doubly occupied-configuration-interaction wave functions
Authors: Alcoba Diego R. , Torre Alicia , Lain Luis , Massaccesi Gustavo E. , Oña Ofelia B. , Ríos Elías
Published: April 2019

This work extends to the unrestricted orbital approach the procedure described in our previous report [Alcoba et al., J. Chem. Phys. 148, 024105 (2018)] for determining variationally the two-electron reduced density matrix arising from doubly occupied-configuration-interaction wave functions by imposing two- and three-index N-representability conditions. An analysis of the numerical results obtained in selected systems, from both restricted and unrestricted treatments, allows one to assess the performance of these methodologies as well as to show the influence of the P, Q, G, T1, and T2 positivity conditions. We highlight the satisfactory results obtained within the unrestricted scheme.
Mid-wavelength infrared InAsSb/InAs nBn detectors and FPAs with very low dark current density
Authors: Soibel Alexander , Ting David Z. , Rafol Sir B. , Fisher Anita M. , Keo Sam A. , Khoshakhlagh Arezou , Gunapala Sarath D.
Published: April 2019

There was a significant improvement in the performance of infrared nBn detectors utilizing InAs/InAsSb absorbers culminating in the development of infrared focal plane arrays (FPAs) with excellent operability (99.7%) and operating at temperature significantly higher than InSb FPAs. In this work, we demonstrated that these detectors can operate with very low dark current densities enabling their use in applications with a low-to-medium level of background illumination. We showed that single pixel photodetectors with a cut-off wavelength of 4.8 μm and a quantum efficiency of QEmax = 35% under backside-illumination have a dark current density of 1 × 10−10 A/cm2 at an operating bias of −0.1 V and temperature T = 100 K. Additionally, we compared the single pixel dark current results with measurements of the dark current in FPAs. The FPA showed excellent performance with an operability of 99.7% and was able to reach a mode dark current density of 5 × 10−11 A/cm2 at 80 K.
Chirality dependence of electron-phonon matrix elements in semiconducting single-walled carbon nanotubes
Authors: Inaba Takumi , Homma Yoshikazu
Published: April 2019

Evaluations of quantum coupling between electrons and phonons in well-defined nanostructure will be necessary when applications based on the vibrations of various materials move into the quantum regime. Raman scattering, in which changes in polarization within a material are probed by light, is an excellent means of analyzing electron-phonon coupling. In this study, the Raman intensities of individually suspended single-walled carbon nanotubes were determined in order to examine variations in electron-phonon interactions in response to changes in the arrangement of carbon atoms (i.e., chirality). Unambiguous assignment of nanotube chirality was achieved by photoluminescence spectroscopy and similar variations in the radial breathing mode and intermediate frequency mode peak intensities with changes in chirality were found. These phenomena were explained based on prior theoretical studies. The D-mode and G-mode peaks were also observed to respond in the same manner, based on which we assigned the longitudinal optical phonon branch to the D-mode. The results of this work demonstrate that the Raman intensity analysis can provide useful information regarding electron-phonon coupling in nanomaterials.
Analysis and optimization of microwave reflections in a plasma-metal model
Authors: Yao Jingfeng , Yu Zhi , Yuan Chengxun , Wei Junjie , Wang Ying , Zhou Zhongxiang , Wang Xiaoou , Kudryavtsev A. A.
Published: April 2019

The problem of interaction of microwaves with plasma is complicated and has garnered considerable interest. Parameters of plasma density, collision frequency, and plasma size have been shown to exert substantial impacts on microwave transmission in plasma. The respective influences of plasma parameters can be evaluated relatively easily; however, plasma must also be considered integrally as it is an electrically neutral medium. In this paper, using a designed plasma-metal model, we assess how plasma parameters influence the interaction of microwaves in plasma, revealing a nonmonotonic and complex relationship. Using parameter optimization, we obtain plasma parameters for plasma device design that meet the requirements of microwave transmission in plasma; the findings should prove useful in applications of electromagnetic waves in plasma.
Low-frequency Raman spectra of a glass-forming ionic liquid at low temperature and high pressure
Authors: Lima Thamires A. , Ribeiro Mauro C. C.
Published: April 2019

The frequency range below ∼100 cm−1 of the Raman spectrum of a glass-forming liquid exhibits two features that characterize the short-time (THz) dynamics: the quasi-elastic scattering (QES) tail and the boson peak (BP). In this work, we follow temperature and pressure effects on the intermolecular dynamics of a typical ionic liquid, 1-butyl-1-methylpiperidinium bis(trifluoromethanesulfonyl)imide, [Pip14][[NTf2]. The glass transition temperature of [Pip14][[NTf2] at atmospheric pressure is Tg = 198 K, and the pressure of glass transition at room temperature is Pg = 1.1 GPa. Raman spectra obtained while cooling the liquid or heating the glass exhibit hysteresis in QES and BP intensities, IQES and IBP. The dependence of IQES, IBP, and the BP frequency, ωBP, with pressure up to the glass transition is steeper than the temperature dependence due to the stronger pressure effect on density within the GPa range. The temperature and pressure behaviors of the parameters IQES, IBP, and ωBP obtained here for [Pip14][[NTf2] are discussed in light of known results for other glass-formers.
Effects of substrate on the structure and properties of V2O5 thin films prepared by the sol-gel method
Authors: Liu Yaqiang , Chen Qingqing , Du Xuelian , Liu Xueqin , Li Peng
Published: April 2019

Vanadium pentoxide (V2O5) thin films were prepared by sol-gel spin coating on Si and glass substrates. X-ray diffraction indicated that the annealed V2O5 film grown on Si substrate was a α-phase orthorhombic structure, while the annealed V2O5 film grown on glass substrates was a β-phase monoclinic structure. Raman spectroscopy revealed the formation of a V-O bond on both phase films. Scanning electron microscopy (SEM) showed that the annealed film on the Si substrate exhibited more uniform rod-like morphology compared with glass substrate film. Electrical measurements indicated the typical n-type semiconducting behavior of both annealed films coated on Si and glass substrates.
Metal–organic complexes as a major sink for rare earth elements in soils
Authors: Fedotov Petr S. , Rogova Olga B. , Dzhenloda Rustam Kh. , Karandashev Vasily K.
Published: April 2019

Environmental contextThe role of rare earth elements in soil–plant systems remains unclear. We use continuous-flow extraction, designed to mimic natural conditions while minimising artefacts, to study in vitro chemical fractionation of rare earth elements in soil. The study reveals a predominant association of rare earth elements and metal-organic complexes independent of soil type and contamination, and thereby provides valuable insights into the behaviour of these elements in soil–plant systems.
AbstractThe role of rare earth elements (REEs) in soil–plant systems has attracted increasing attention but still remains somewhat unclear. Along invivo studies on the uptake of REEs by plants, invitro chemical fractionation of REEs in soil according to their physicochemical mobility can offer additional insights into the behaviour of REEs. In the present work, the fractionation of REEs was studied with the example of background, aerially and hydrogenically contaminated soil samples using dynamic (continuous flow) extraction, which allows natural conditions to be mimicked and artefacts to be minimised. The eluents applied addressed exchangeable, specifically sorbed, bound to Mn oxides, bound to metal–organic complexes, and bound to amorphous and poorly ordered Fe/Al oxides fractions extractable by 0.05M Ca(NO3)2, 0.43M CH3COOH, 0.1M NH2OH·HCl, 0.1M K4P2O7 at pH 11, and 0.1M (NH4)2C2O4 at pH 3.2 respectively. The distribution of trace metals (such as Pb, Cu, Zn, Ni) between separated fractions varies with sample and is dependent on the type of contamination. However, for all samples, the recoveries of REEs by pyrophosphate are surprisingly high, up to 40–45% of their total concentrations in background and anthropogenically transformed floodplain soils. As compared to metal–organic complexes, the contents of REEs bound to Fe/Al oxides are fairly low, no more than 12%. REEs in other fractions may be taken into consideration only for aerially contaminated soil. Such a predominant association of REEs and metal–organic complexes (i.e. humic and fulvic compounds) independent of the type of soil has not been reported before.
Intrinsic mutant HTT-mediated defects in oligodendroglia cause myelination deficits and behavioral abnormalities in Huntington disease
Authors: Ferrari Bardile Costanza , Garcia-Miralles Marta , Caron Nicholas S. , Rayan Nirmala Arul , Langley Sarah R. , Harmston Nathan , Rondelli Ana Maria , Teo Roy Tang Yi , Waltl Sabine , Anderson Lisa M. , Bae Han-Gyu , Jung Sangyong , Williams Anna , Prabhakar Shyam , Petretto Enrico , Hayden Michael R. , Pouladi Mahmoud A.
Published: April 2019

White matter abnormalities are a nearly universal pathological feature of neurodegenerative disorders including Huntington disease (HD). A long-held assumption is that this white matter pathology is simply a secondary outcome of the progressive neuronal loss that manifests with advancing disease. Using a mouse model of HD, here we show that white matter and myelination abnormalities are an early disease feature appearing before the manifestation of any behavioral abnormalities or neuronal loss. We further show that selective inactivation of mutant huntingtin (mHTT) in the NG2+ oligodendrocyte progenitor cell population prevented myelin abnormalities and certain behavioral deficits in HD mice. Strikingly, the improvements in behavioral outcomes were seen despite the continued expression of mHTT in nonoligodendroglial cells including neurons, astrocytes, and microglia. Using RNA-seq and ChIP-seq analyses, we implicate a pathogenic mechanism that involves enhancement of polycomb repressive complex 2 (PRC2) activity by mHTT in the intrinsic oligodendroglial dysfunction and myelination deficits observed in HD. Our findings challenge the long-held dogma regarding the etiology of white matter pathology in HD and highlight the contribution of epigenetic mechanisms to the observed intrinsic oligodendroglial dysfunction. Our results further suggest that ameliorating white matter pathology and oligodendroglial dysfunction may be beneficial for HD.
Forty-six years of Greenland Ice Sheet mass balance from 1972 to 2018
Authors: Mouginot Jérémie , Rignot Eric , Bjørk Anders A. , van den Broeke Michiel , Millan Romain , Morlighem Mathieu , Noël Brice , Scheuchl Bernd , Wood Michael
Published: April 2019

We reconstruct the mass balance of the Greenland Ice Sheet using a comprehensive survey of thickness, surface elevation, velocity, and surface mass balance (SMB) of 260 glaciers from 1972 to 2018. We calculate mass discharge, D, into the ocean directly for 107 glaciers (85% of D) and indirectly for 110 glaciers (15%) using velocity-scaled reference fluxes. The decadal mass balance switched from a mass gain of +47

±

21 Gt/y in 1972–1980 to a loss of 51

±

17 Gt/y in 1980–1990. The mass loss increased from 41

±

17 Gt/y in 1990–2000, to 187

±

17 Gt/y in 2000–2010, to 286

±

20 Gt/y in 2010–2018, or sixfold since the 1980s, or 80

±

6 Gt/y per decade, on average. The acceleration in mass loss switched from positive in 2000–2010 to negative in 2010–2018 due to a series of cold summers, which illustrates the difficulty of extrapolating short records into longer-term trends. Cumulated since 1972, the largest contributions to global sea level rise are from northwest (4.4

±

0.2 mm), southeast (3.0

±

0.3 mm), and central west (2.0

±

0.2 mm) Greenland, with a total 13.7

±

1.1 mm for the ice sheet. The mass loss is controlled at 66

±

8% by glacier dynamics (9.1 mm) and 34

±

8% by SMB (4.6 mm). Even in years of high SMB, enhanced glacier discharge has remained sufficiently high above equilibrium to maintain an annual mass loss every year since 1998.
Modelling school participation based on the theory of planned behaviour / Modelamiento de la participación escolar basado en la teoría del comportamiento planificado
Authors: Awad-Carrillo Alia , Pérez-Salas Claudia-Paz , Sirlopú David
Published: April 2019

This study evaluated a predictive model of school participation based on Ajzen’s theory of planned behaviour. Attitudes towards social justice, perceived control and subjective norm on school participation were tested, mediated by the behavioural intention in favour of social justice in a sample of 443 secondary school students. The proposed model showed good fit (χ2 = 597.740, df = 342; RMSEA = .041). The behavioural intentions towards social justice and perceived behavioural control were directly related to school participation. An indirect effect of perceived control on participation was detected, mediated by behavioural intention, but no evidence was found of the indirect effect of either attitude or norm on school participation.
Lupeol suppresses migration and invasion via p38/MAPK and PI3K/Akt signaling pathways in human osteosarcoma U-2 OS cells
Authors: Hsu Ming-Jie , Peng Shu-Fen , Chueh Fu-Shin , Tsai Chang-Hai , Tsai Fuu-Jen , Huang Chih-Yang , Tang Chih-Hsin , Yang Jai-Sing , Hsu Yuan-Man , Huang Wen-Wen , Chung Jing-Gung
Published: April 2019

Lupeol, one of the common components from the fruits and natural foods, has been reported to exert antitumor activities in many human cancer cell lines; however, its effects on osteosarcoma cell metastasis were not elucidated. In the present study, lupeol at 10–25 μM induced cell morphological changes and decreased total viable cell number in U-2 OS cells. Lupeol (5–15 μM) suppressed cell mobility, migration, and invasion by wound healing and transwell chamber assays, respectively. Lupeol inhibited the activities of MMP-2 and −9 in U-2 OS cells by gelatin zymography assay. Lupeol significantly decreased PI3K, pAKT, β-catenin, and increased GSK3β. Furthermore, lupeol decreased the expressions of Ras, p-Raf-1, p-p38, and β-catenin. Lupeol also decreased uPA, MMP-2, MMP-9, and N-cadherin but increased VE-cadherin in U-2 OS cells. Based on these observations, we suggest that lupeol can be used in anti-metastasis of human osteosarcoma cells in the future.
Hes1 attenuates type I IFN responses via VEGF-C and WDFY1
Authors: Ning Fei , Li Xiaoyu , Yu Li , Zhang Bin , Zhao Yuna , Liu Yu , Zhao Baohong , Shang Yingli , Hu Xiaoyu
Published: April 2019

Induction of type I interferons (IFNs) is critical for eliciting competent immune responses, especially antiviral immunity. However, uncontrolled IFN production contributes to pathogenesis of autoimmune and inflammatory diseases. We found that transcription factor Hes1 suppressed production of type I IFNs and expression of IFN-stimulated genes. Functionally, Hes1-deficient mice displayed a heightened IFN signature in vivo, mounted enhanced resistance against encephalomyocarditis virus infection, and showed signs of exacerbated experimental lupus nephritis. Mechanistically, Hes1 did not suppress IFNs via direct transcriptional repression of IFN-encoding genes. Instead, Hes1 attenuated activation of TLR upstream signaling by inhibition of an adaptor molecule, WDFY1. Genome-wide assessment of Hes1 occupancy revealed that suppression of WDFY1 was secondary to direct binding and thus enhancement of expression of VEGF-C by Hes1, making Vegfc a rare example of an Hes1 positively regulated gene. In summary, these results identified Hes1 as a homeostatic negative regulator of type I IFNs for the maintenance of immune balance in the context of antiviral immunity and autoimmune diseases.
Understanding current-driven dynamics of magnetic Néel walls in heavy metal/ferromagnetic metal/oxide trilayers
Authors: Li Mei , Wang Jianbo , Lu Jie
Published: April 2019

We consider analytically current-driven dynamics of magnetic Néel walls in heavy metal/ferromagnetic metal/oxide trilayers where strong spin–orbit coupling and interfacial Dzyaloshinskii–Moriya interaction (i-DMI) coexist. We show that field-like spin–orbit torque (FL-SOT) with effective field along

n
×

J

ˆ

(n being the interface normal and

J

ˆ

being the charge current direction) and i-DMI induced torque can both lead to Walker breakdown suppression meanwhile leaving the wall mobility (velocity versus current density) unchanged. However, i-DMI itself can not induce the ‘universal absence of Walker breakdown’ (UAWB) while FL-SOT exceeding a certain threshold can. Finitely-enlarged Walker limits before UAWB are theoretically calculated and well explain existing data. In addition, change in wall mobility and even its sign-inversion can be understood only if the anti-damping-like SOT is appended. For Néel walls in ferromagnetic-metal layer with both perpendicular and in-plane anisotropies, we have calculated the respective modifications of wall mobility under the coexistence of spin-transfer torque, SOTs and i-DMI. Analytics shows that in trilayers with perpendicular anisotropy strong enough spin Hall angle and appropriate sign of i-DMI parameter can lead to sign-inversion in wall mobility even under small enough current density, while in those with in-plane anisotropy this only occurs for current density in a specific range.
Realising single-shot measurements of quantum radiation reaction in high-intensity lasers
Authors: Baird C D , Murphy C D , Blackburn T G , Ilderton A , Mangles S P D , Marklund M , Ridgers C P
Published: April 2019

Modern laser technology is now sufficiently advanced that collisions between high-intensity laser pulses and laser-wakefield-accelerated (LWFA) electron beams can reach the strong-field regime, so that it is possible to measure the transition between the classical and quantum regimes of light–matter interactions. However, the energy spectrum of LWFA electron beams can fluctuate significantly from shot to shot, making it difficult to clearly discern quantum effects in radiation reaction (RR), for example. Here we show how this can be accomplished in only a single laser shot. A millimetre-scale pre-collision drift allows the electron beam to expand to a size larger than the laser focal spot and develop a correlation between transverse position and angular divergence. In contrast to previous studies, this means that a measurement of the beam’s energy-divergence spectrum automatically distinguishes components of the beam that hit or miss the laser focal spot and therefore do and do not experience RR.
Robust nonreciprocal acoustic propagation in a compact acoustic circulator empowered by natural convection
Authors: Liu Xingxing , Cai Xiaobing , Guo Qiuquan , Yang Jun
Published: April 2019

The development of the quantum Hall effect in condensed matter physics that breaks time-reversal symmetry by magnetic biasing has inspired its analog in classical nonreciprocal acoustics. Nonreciprocal acoustic propagation is highly desirable to control acoustics in isolation, broadband unidirectional transmission, and topologically robust to structural disorders or defects. So far, these fascinating properties have been investigated through fan-induced moving media, acoustic capacitance adjustment and acoustic metamaterials. However, these may be associated with disadvantages including extra noise and limited dynamic controlling performance. Here we overcome these limitations by introducing heat-induced natural convection into acoustic circulator, and demonstrate that the classical acoustic circulator with thermal management can realize robust nonreciprocal acoustic propagation. The concept of combining heat-induced natural convection and aeroacoustics creates a new practical paradigm and increases the feasibility for nonreciprocal acoustics due to merits of dynamic control, versatile topological structures, and miniaturization in the absence of moving parts.
Quantum interference of multi-photon at beam splitter with application in measurement-device-independent quantum key distribution
Authors: Pradana Andri , Chew Lock Yue
Published: April 2019

Despite the relative simplicity of the traditional Hong–Ou–Mandel (HOM) interferometer setup, it is of fundamental interest in various quantum optics applications and quantum information technologies. In this article, multi-photon interference using the original HOM interferometer setup is analyzed. More specifically, for any photon number state with Gaussian spectral distribution entering the beam splitter, the general analytical solution is calculated. The result is then used to study the coincident probability for coherent sources (laser) and squeezed coherent state. We also look into the potential benefits of implementing the squeezed coherent state in discrete-variable Measurement-Device-Independent Quantum Key Distribution and find that by optimizing the squeezing parameter, the error rate can be significantly reduced. This in turn also enhances the secret key rate performance over the coherent state.
TractaViewer: a genome-wide tool for preliminary assessment of therapeutic target druggability
Authors: Pearson Neil , Malki Karim , Evans David , Vidler Lewis , Ruble Cara , Scherschel James , Eastwood Brian , Collier David A
Published: April 2019

We present software to characterize and rank potential therapeutic (drug) targets with data from public databases and present it in a user-friendly format. By understanding potential obstacles to drug development through the gathering and understanding of this information, combined with robust approaches to target validation to generate therapeutic hypotheses, this approach may provide high quality targets, leading the process of drug development to become more efficient and cost-effective.

Availability and implementation

The information we gather on potential targets concerns small-molecule druggability (ligandability), suitability for large-molecule approaches (e.g. antibodies) or new modalities (e.g. antisense oligonucleotides, siRNA or PROTAC), feasibility (availability of resources such as assays and biological knowledge) and potential safety risks (adverse tissue-wise expression, deleterious phenotypes). This information can be termed ‘tractability’. We provide visualization tools to understand its components. TractaViewer is available from https://github.com/NeilPearson-Lilly/TractaViewer

Supplementary information

Supplementary data are available at Bioinformatics online.
Multiple peritricuspidal reentry tachycardias after cardiac infiltration by leukaemia: a case report
Authors: Kawamura Iwanari , Fukamizu Seiji , Miyazawa Satoshi , Hojo Rintaro
Published: April 2019

Background

Cardiac involvement by malignant lymphocytic neoplasms is a rare phenomenon. Little is known concerning cardiotoxicity in the chronic phase after completion of treatment.

Case summary

A 50-year-old woman with a past history of cardiac involvement of acute lymphoblastic leukaemia (ALL) underwent electrophysiologic study and catheter ablation for symptomatic atrial tachycardia (AT). She was diagnosed with ALL when she was 8 years old and treated with systematic chemotherapy with prednisolone and vincristine. After complete remission, she suffered from repeated palpitations beginning at the age of 16 years. Electrophysiologic study using high-density (HD) mapping showed two types of peritricuspid AT in addition to low voltage in the right atrium with conduction delay.

Discussion

Cardiac involvement by malignant lymphocytic neoplasms is a rare phenomenon, and cardiac infiltration often disappears after remission of ALL. Thus, little is known about cardiac electrophysiological characteristics in the chronic phase of complete remission of ALL. We describe a rare case of a patient with multiple peritricuspidal reentry tachycardias after cardiac infiltration by leukaemia using a HD mapping system.
Giant unruptured aneurysm of the left coronary sinus of Valsalva presenting as acute coronary syndrome: a case report
Authors: Mørk Sivagowry Rasalingam , Eftekhari Ashkan , Tang Mariann , Klaaborg Kaj-Erik
Published: April 2019

Background

Sinus of Valsalva aneurysm (SVA) is a rare cardiac anomaly that can be congenital or acquired. Unruptured aneurysms may be asymptomatic but can present as malignant arrhythmias, acute chest pain, and even sudden cardiac death. Both ruptured and unruptured SVAs may have fatal complications, thus prompt diagnosis and surgery is critical.

Case summary

We report a successful surgical repair of an unruptured aneurysm of the left sinus of Valsalva presenting as acute coronary syndrome. Coronary angiography (CAG) and cardiac multislice computed tomography (CT) revealed a large unruptured aneurysm of the left sinus of Valsalva. Surgical repair was performed by resection of the aneurysm, aortic valve replacement with composite graft, and coronary artery bypass.

Discussion

Aneurysm of the left sinus of Valsalva is an extremely rare condition. Correct diagnosis can be done by echocardiography, CAG, or CT. Non-ruptured aneurysms should be surgically repaired if they are associated with significant symptoms or if their size enlarge rapidly.
Neighbourhood Ethnic Composition and Social Participation of Young People in England
Authors: Fumagalli Elena , Fumagalli Laura
Published: April 2019

We analyse how neighbourhood ethnic diversity and segregation affect adolescents’ social participation in England. We distinguish between participation in ‘purposeful activities’—such as sports and volunteering—and hanging around with friends. We suggest a novel identification strategy to address the problem of endogeneity of ethnic diversity and segregation. We find that ethnic diversity decreases hanging around, while ethnic segregation increases it. No effects on participation in purposeful activities are found.