bluuebunny/crossref_metadata_2025 huggingface dataset:
Temperature evolution of frequency and anharmonic phonon loss for multi-mode epitaxial HBARs
Authors: Gokhale Vikrant J. , Downey Brian P. , Katzer D. Scott , Meyer David J.
Published: September 2020

This Letter reports measured cryogenic temperature trends for over 300 longitudinal phonon modes spanning >10 GHz in an epitaxial GaN/NbN/SiC high overtone bulk acoustic resonator (epi-HBAR). We present temperature profiles from 7.2 K to 200 K for the mode frequency (f), the quality factor (Q), the figure of merit (f×Q), and the phonon loss or attenuation coefficient (α). We show that for all m phonon modes, fmT follows an identical parabolic trend, with a zero-slope turnover temperature of 35 K. Thus, the epi-HBAR comb spectrum can be considered an ensemble of modes with the same temperature dependencies, potentially enabling the design of precise multi-mode temperature-stable RF oscillators and clocks operating at GHz frequencies. Using temperature trends for (f×Q)m and αm, we provide strong evidence that the epi-HBARs are fundamentally limited by anharmonic phonon scattering in the materials that make up the epi-HBAR. Crucially, we unambiguously demonstrate the evolution of this anharmonic phonon scattering from the low frequency Akhiezer scattering regime αm∝T1 to the high frequency Landau–Rumer scattering regime αm∝T4, using hundreds of phonon modes in the same device. Finally, we show that at extremely low temperatures, other emergent loss mechanisms overshadow anharmonic phonon scattering. This finding motivates further investigation into the root causes of these limiting mechanisms for precision RF signal processing, quantum acoustodynamics, and other applications that require extremely low loss micromechanical devices.
Analysis of low-threshold optically pumped III-nitride microdisk lasers
Authors: Tabataba-Vakili Farsane , Brimont Christelle , Alloing Blandine , Damilano Benjamin , Doyennette Laetitia , Guillet Thierry , El Kurdi Moustafa , Chenot Sébastien , Brändli Virginie , Frayssinet Eric , Duboz Jean-Yves , Semond Fabrice , Gayral Bruno , Boucaud Philippe
Published: September 2020

Low-threshold lasing under pulsed optical pumping is demonstrated at room temperature for III-nitride microdisks with InGaN/GaN quantum wells on Si in the blue spectral range. Thresholds in the range of 18 kW/cm2 have been achieved along with narrow linewidths of 0.07 nm and a large peak-to-background dynamic of 300. We compare this threshold range with the one that can be calculated using a rate equation model. We show that thresholds in the few kW/cm2 range constitute the best that can be achieved with III-nitride quantum wells at room temperature. The sensitivity of lasing on the fabrication process is also discussed.
Electronic and optical properties of low-dimensional group-IV monochalcogenides
Authors: C. Gomes Lídia , Carvalho A.
Published: September 2020

The group-IV monochalcogenides are a set of binary materials MX composed by a group-IV element (M=Sn or Ge) and a chalcogen (X=S or Se). Strong anisotropy is one of the most interesting facets of these materials, especially in their low-dimensional form. In this Tutorial, we present some of the recent studies on the electronic and optical properties of 2D group-IV monochalcogenides, including predictions from first-principles density functional theory calculations and available experimental observations. We discuss the variation of the bandgap from bulk down to monolayer and the respective band structures, which are characterized by multiple valence and conduction band valleys, making these materials suitable for a variety of applications, including valleytronics. We also discuss the emergence of spin–orbit splitting, piezoelectricity, and ferroelectricity as a result of the polar character of the monolayers. Current predictions of carrier mobilities in monolayers and their potential application as thermoelectric materials are also presented.
Crystal alignment of a LiNi0.5Mn0.3Co0.2O2 electrode material for lithium ion batteries using its magnetic properties
Authors: Kim Cham , Yang Yeokyung , Lopez David Humberto , Ha Dongwoo
Published: September 2020

We studied technology that enables the crystal alignment of LiNi0.5Mn0.3Co0.2O2 using its magnetic properties. LiNi0.5Mn0.3Co0.2O2 exhibited either antiferromagnetic or paramagnetic behavior depending on temperature as well as magnetic anisotropy originated from its crystallographic anisotropy. Based on these magnetic characteristics, we adjusted the vector quantity of an external magnetic field and applied it to LiNi0.5Mn0.3Co0.2O2 crystals, thus producing crystal-aligned LiNi0.5Mn0.3Co0.2O2 electrodes. In these electrodes, the (00l) plane was oriented comparatively perpendicular to the surface of a current collector. Due to the intrinsic lithium ion transport kinetics in LiNi0.5Mn0.3Co0.2O2 along the (00l) plane, aligned LiNi0.5Mn0.3Co0.2O2 may contribute to enhancing lithium ion conduction during the charge/discharge process in a lithium ion battery, resulting in improved electrochemical performance.
Microwave plasma discharges for biomass pretreatment: Degradation of a sodium carboxymethyl cellulose model
Authors: Honnorat B. , Brüser V. , Kolb J. F.
Published: September 2020

Biogas production is an important component of an environmentally benign renewable energy strategy. However, the cost-effectiveness of biogas production from biomass is limited by the presence of polymeric structures, which are recalcitrant to digestion by bacteria. Therefore, pretreatments must often be applied prior to anaerobic fermentation to increase yields of biogas. Many physico-chemical pretreatments have a high energy demand and are generally costly. An alternative could be the ignition of a plasma directly in the biomass substrate. The reactive species that are generated by plasma–liquid interactions, such as hydroxyl radicals and hydrogen peroxides, could contribute significantly to the disintegration of cell walls and the breakage of poorly digestible polymers. With respect to economic, processing, and other potential benefits, a microwave instigated and sustained plasma was investigated. A microwave circuit transmitted 2-kW pulses into a recirculated sodium carboxymethyl cellulose solution, which mimicked the rheological properties of biomass. Each microwave pulse had a duration of 12.5 ms and caused the ignition of a discharge after a vapor bubble had formed. Microwaves were absorbed in the process with an efficiency of ∼97%. Slow-motion imaging showed the development of the discharge. The plasma discharges provoked a decrease in the viscosity, probably caused by the shortening of polymer chains of the cellulose derivative. The decrease in viscosity by itself could reduce processing costs and promotes bacterial activity in actual biomass. The results demonstrate the potential of microwave in-liquid plasma discharges for the pretreatment of biomass.
Investigation of shock wave interactions involving stationary and moving wedges
Authors: Seshadri Pradeep Kumar , De Ashoke
Published: September 2020

The present study investigates the shock wave interactions involving stationary and moving wedges using a sharp interface immersed boundary method combined with a fifth-order weighted essentially non-oscillatory scheme. Inspired by Schardin’s problem, which involves moving shock interaction with a finite triangular wedge, we study the influence of incident shock Mach numbers and corner angles on the resulting flow physics under both stationary and moving conditions. The present study involves three incident shock Mach numbers (1.3, 1.9, and 2.5) and three corner angles (60°, 90°, and 120°), while its impact on the vorticity production is investigated using the vorticity transport equation, circulation, and rate of circulation production. Furthermore, the results yield that the generation of the vorticity due to the viscous effects is quite dominant compared to the baroclinic or compressibility effects. The moving cases presented involve shock driven wedge problems. The fluid and wedge structure dynamics are coupled using the Newtonian equation. These shock driven wedge cases show that wedge acceleration due to the shock results in a change in reflected wave configuration from single Mach reflection to double Mach reflection. The intermediary state between them, the transition Mach reflection, is also observed in the process. The effect of shock Mach numbers and corner angles on the triple point trajectory, as well as on the drag coefficient, is analyzed in this study.
Observation of inter-layer charge transmission resonance at optically excited graphene–TMDC interfaces
Authors: Kashid Ranjit , Mishra Jayanta Kumar , Pradhan Avradip , Ahmed Tanweer , Kakkar Saloni , Mundada Pranav , Deshpande Preeti , Roy Kallol , Ghosh Ambarish , Ghosh Arindam
Published: September 2020

The transfer of charge carriers across the optically excited hetero-interface of graphene and semiconducting transition metal dichalcogenides (TMDCs) is the key to convert light to electricity, although the intermediate steps from the creation of excitons in TMDC to the collection of free carriers in the graphene layer are not fully understood. Here, we investigate photo-induced charge transport across graphene–MoS2 and graphene–WSe2 hetero-interfaces using time-dependent photoresistance relaxation with varying temperature, wavelength, and gate voltage. In both types of heterostructures, we observe an unprecedented resonance in the inter-layer charge transfer rate as the Fermi energy (EF) of the graphene layer is tuned externally with a global back gate. We attribute this to a resonant quantum tunneling from the excitonic state of the TMDC to EF of the graphene layer and outline a new method to estimate the excitonic binding energies (Eb) in the TMDCs, which are found to be 400 meV and 460 meV in MoS2 and WSe2 layers, respectively. The gate tunability of the inter-layer charge transfer timescales may allow precise engineering and readout of the optically excited electronic states at graphene–TMDC interfaces.
New power-law scaling for friction factor of extreme Reynolds number pipe flows
Authors: Anbarlooei H. R. , Cruz D. O. A. , Ramos F.
Published: September 2020

We report a novel power-law scaling for the friction factor of incompressible Newtonian fluid flows at extreme Reynolds numbers: f = Ce/Re2/13. The formula is based on a new phenomenology for coherent structures that dominate the momentum exchange in meso-layer regions and scales with the geometric mean δδν, where δν is the viscous length scale and δ is the pipe radius. Comparisons with the experimental data from the Princeton Superpipe and the Hi-Reff Facility at the National Metrology Institute of Japan show excellent agreement for a large range of Reynolds numbers. This work, along with the recent empirical evidence, suggests a possible change in the mechanism of turbulent momentum transfer for pipe flows in extreme Reynolds numbers.
Acceptor complex signatures in oxygen-rich ZnO thin films implanted with chlorine ions
Authors: Azarov Alexander , Galeckas Augustinas , Venkatachalapathy Vishnukanthan , Mei Zengxia , Du Xiaolong , Monakhov Eduard , Kuznetsov Andrej
Published: September 2020

Spectroscopic identification of defects and impurities is crucial for understanding doping asymmetry issues in ZnO and, therefore, realization of true ZnO-based bipolar devices. Chlorine (Cl) is an amphoteric impurity in ZnO exhibiting acceptor behavior in the interstitial configuration and donor action once on substitutional oxygen sites (ClO). In its turn, the incorporation of Cl atoms depends on the material growth conditions and a ClO fraction should be suppressed in O-rich materials. In the present work, Cl ions were implanted into ZnO thin films synthesized under O-rich conditions. In contrast to a negligible effect of Cl incorporation to electrical conductivity, photoluminescence measurements revealed dramatic developments of optical properties with a strong acceptor-like spectral signature emerging after 900 °C anneals. We discuss the origins of a new excitonic I* line (3.355 eV) induced by Cl-implantation and propose two alternative defect models based on shallow acceptor and shallow donor complexes.
Analysis of the Griffiths–like phase observed in binary ε-Fe2N nitride
Authors: Wang Wei , Kan Xucai , Liu Xiansong , Dao Yan , Feng Shuangjiu , Li Yong , Liu Chaocheng , Shezad Mudssir , Zhang Zhitao , Mehmood Ur Rehman Khalid
Published: September 2020

The structure and magnetic properties of binary ε-Fe2N nitride are investigated systematically and a Griffiths-like phase (GP) behavior is observed at low magnetic field. On cooling, the inverse magnetic susceptibility (1/χ) curve reveals that the GP behavior appears at 260 K. By the electron spin resonance spectra measurement and the density functional theory calculation, we suggest that the short-range ferromagnetic clusters and the local disorder within the crystallographic structure, which are stabilized and enhanced from the completion of the intra-layer Fe–Fe and inter-layer Fe–N–Fe interactions, contribute to the GP behavior.
Electronic structure calculations in electrolyte solutions: Methods for neutralization of extended charged interfaces
Authors: Bhandari Arihant , Anton Lucian , Dziedzic Jacek , Peng Chao , Kramer Denis , Skylaris Chris-Kriton
Published: September 2020

Density functional theory (DFT) is often used for simulating extended materials such as infinite crystals or surfaces, under periodic boundary conditions (PBCs). In such calculations, when the simulation cell has non-zero charge, electrical neutrality has to be imposed, and this is often done via a uniform background charge of opposite sign (“jellium”). This artificial neutralization does not occur in reality, where a different mechanism is followed as in the example of a charged electrode in electrolyte solution, where the surrounding electrolyte screens the local charge at the interface. The neutralizing effect of the surrounding electrolyte can be incorporated within a hybrid quantum–continuum model based on a modified Poisson–Boltzmann equation, where the concentrations of electrolyte ions are modified to achieve electroneutrality. Among the infinite possible ways of modifying the electrolyte charge, we propose here a physically optimal solution, which minimizes the deviation of concentrations of electrolyte ions from those in open boundary conditions (OBCs). This principle of correspondence of PBCs with OBCs leads to the correct concentration profiles of electrolyte ions, and electroneutrality within the simulation cell and in the bulk electrolyte is maintained simultaneously, as observed in experiments. This approach, which we call the Neutralization by Electrolyte Concentration Shift (NECS), is implemented in our electrolyte model in the Order-N Electronic Total Energy Package (ONETEP) linear-scaling DFT code, which makes use of a bespoke highly parallel Poisson–Boltzmann solver, DL_MG. We further propose another neutralization scheme (“accessible jellium”), which is a simplification of NECS. We demonstrate and compare the different neutralization schemes on several examples.
A unified model to study the effects of elasticity, viscosity, and magnetic fields on linear Richtmyer–Meshkov instability
Authors: Sun Y. B. , Wang C. , Piriz A. R.
Published: September 2020

A unified analytical approach to study the effects of elasticity, viscosity, and magnetic fields on the Richtmyer–Meshkov (RM) instability by using the impulsively accelerated model is presented. This model clarifies the discontinuity in the oscillation periods and yields the asymptotic decaying rate in elastic solids. It reveals that the complex eigenvalues produce better results compared with the numerical simulations for RM instability in viscous fluids and resolves the standing controversy between the analytical theory and numerical simulations at a vacuum/fluid interface. At last, it easily retrieves the results when the normal or tangential magnetic field is present. Those good agreements, between numerical simulations and theoretical analysis, would enable the model to be valuable in more complex situations such as in the elastic–plastic slabs with or without the presence of magnetic fields, as well as in the nonlinear regime.
Stable polarization entanglement based quantum key distribution over a deployed metropolitan fiber
Authors: Shi Yicheng , Moe Thar Soe , Poh Hou Shun , Grieve James A. , Kurtsiefer Christian , Ling Alexander
Published: September 2020

We demonstrate a quantum key distribution (QKD) implementation over deployed dark telecom fibers with polarization-entangled photons generated at the O-band. One of the photons in the pairs is propagated through 10 km of deployed fiber, while the others are detected locally. Polarization drifts experienced by the photons propagating through the fibers are compensated with liquid crystal variable retarders. This ensures continuous and stable QKD operation with an average quantum bit error rate of 6.4% and a final key rate of 109 bits/s.
Dynamical stability, vibrational, and optical properties of anti-perovskite A3BX (Ti3TlN, Ni3SnN, and Co3AlC) phases: A first principles study
Authors: Das K. , Ali M. A. , Hossain M. M. , Naqib S. H. , Islam A. K. M. A. , Uddin M. M.
Published: September 2020

We have investigated various physical properties including phonon dispersion, thermodynamic parameters, optical constants, Fermi surface, Mulliken bond population, theoretical Vickers hardness, and damage tolerance of anti-perovskite A3BX phases for the first time by employing density functional theory methodology based on the first principles method. Initially, we assessed nine A3BX phases in total and found that only three phases (Ti3TlN, Ni3SnN, and Co3AlC) are mechanically and dynamically stable based on the analysis of computed elastic constants and phonon dispersion along with phonon density of states. We revisited the structural, elastic, and electronic properties of the compounds to judge the reliability of our calculations. The absence of bandgap at the Fermi level characterizes the phases under consideration as metallic in nature. The values of Pugh ratio, Poisson’s ratio, and Cauchy factor have predicted the ductile nature associated with strong metallic bonding in these compounds. A high temperature feasibility study of the phases has also been performed using the thermodynamic properties, such as the free energy, enthalpy, entropy, heat capacity, and Debye temperature. The Vickers hardness of the compounds is estimated to be ∼4 GPa, which is comparable to many well-known MAX phases, indicating their reasonable hardness and easily machinable nature. The static refractive index n(0) has been found around ∼8.0 for the phases under study that appeals as a potential candidate to design optoelectronics appliances. The reflectivity is found above 44% for the Ti3TlN compound in the energy range of 0 eV–14.8 eV, demonstrating that this material holds significant promise as a coating agent to avoid solar heating.
Surfactant-added hydrophilic polydimethylsiloxane (PDMS) as mold material for thermoplastic hot embossing process
Authors: Lee Bom-yee , Lee Bong-Kee
Published: September 2020

In the present study, a hot embossing process employing a hydrophilic polydimethylsiloxane (PDMS) mold was investigated considering the effect of the surface wettability of the mold on the replication quality of microfeatures. To turn the hydrophobicity of native PDMS into hydrophilicity, Silwet L-77 was employed as a surfactant in preparing a mold for a microcavity. Hot embossing experiments imprinting the microfeature onto thermoplastic sheets were performed with both a surfactant-modified mold and a native PDMS mold. A design of the experiment approach based on an orthogonal array was employed to investigate the effects of the relevant factors, including wettability and processing parameters. The characteristic dimensions of the hot-embossed microfeature were measured to evaluate the replication quality. The increased wettability of the PDMS mold surface was found to efficiently improve the replication quality of the microfeature. The major processing parameters of the hot embossing process, such as the embossing temperature, pressure, and time, were also investigated.
A novel dielectric breakdown apparatus for solid-state nanopore fabrication with transient high electric field
Authors: Fang Shaoxi , Yin Bohua , Xie Wanyi , Zhou Daming , Tang Peng , He Shixuan , Yuan Jiahu , Wang Deqiang
Published: September 2020

The dielectric breakdown used to fabricate solid-state nanopores has separated the device from capital-intensive industries and has been widely adopted by various research teams, but there are still problems with low production efficiency and uncertain location. In this work, based on the transient breakdown phenomenon of nanofilms, a new type of dielectric breakdown apparatus for nanopore fabrication is reported. It integrates both nano-manipulation technology and dielectric breakdown nanopore fabrication technology. The nanometer distance detection method and circuit are introduced in detail. The generation principle and procedures of the transient high electric field are explained step by step. The characterization of the nanopores shows that this apparatus can fabricate sub-2 nm nanopores at a pre-located position. Besides, the nanopore diameter can be easily adjusted by setting the transient high electric field value.
Experimental synthesis of random light sources with circular coherence by digital micro-mirror device
Authors: Zhu Xinlei , Yu Jiayi , Chen Yahong , Wang Fei , Korotkova Olga , Cai Yangjian
Published: September 2020

We introduce an optical system for the nearly real-time generation of a wide class of partially coherent sources (PCSs) having non-Schell-model circular coherence. The system is composed of a modified 4f optical imaging system involving a fast modulated digital micro-mirror device (DMD) and a stable common path interferometric arrangement, which enable us to synthesize a variety of PCSs not reported heretofore. The basic principle and physics of our method, as well as the experimental implementation for generating two kinds of non-uniformly correlated (NUC) sources, i.e., cosh-type and sinh-type NUC sources, are presented, confirming the flexibility and reliability of our proposed approach. We further demonstrate the non-uniform property of the spatial correlation of the generated NUC sources by means of a classic Young's interferometer.
Solitary waves of nonlinear barotropic–baroclinic coherent structures
Authors: Wang Jie , Zhang Ruigang , Yang Liangui
Published: September 2020

This study describes the evolutionary mechanisms of nonlinear barotropic–baroclinic interactions, especially, on the excitations, propagations, and decreases of nonlinear coherent structures. Starting from the classical two-layer quasi-geostrophic potential vorticity conservation model equations, the barotropic and baroclinic model equations are derived from the classical work of Pedlosky and Thomson [J. Fluid Mech. 490, 189–215 (2003)]. By considering the effects of bottom topography and beta-plane approximation, the coupled nonlinear Korteweg–de Vries model equations for the evolutions of barotropic and baroclinic coherent structures are obtained by using the methods of multiple scales and perturbation expansions, respectively. Solitary wave solutions are given according to the method of elliptic function expansions, and the physical mechanisms for the evolutions of the nonlinear barotropic–baroclinic interactive coherent structures are analyzed based on the obtained solitary wave solutions. It will be potentially useful for further theoretical investigations on atmospheric blocking phenomena or wave–flow interactions.
Semiclassical Electron Transport
Authors: Levi A. F. J.
Published: September 2020

This chapter provides a convenient survey of useful semiclassical concepts and associated devices. Quantized conductance as a consequence of the plane-wave description of electrons with an effective mass and motion in one dimension is described first. Following this, the Coulomb blockade and its application to the single-electron transistor is introduced. Then, purely classical concepts of forces due to collisions of point electron particles giving rise to current, conductivity, and mobility are defined. Electron group velocity in a semiconductor band structure, ballistic electron motion, and, in the absence of scattering, the prediction of Bloch oscillations in the presence of a constant electric field are described. The effect of electron scattering that results in nonlinear electron velocity–field characteristics and its application to the Gunn diode are used to motivate a description in terms of the Boltzmann transport equation. A semiclassical approach to calculating electron elastic scattering rates from randomly positioned ionized substitutional impurities using a Thomas–Fermi dielectric screening is given along with its connection to experimentally measured electron mobility in n-type GaAs. The chapter concludes by briefly mentioning the large values of electron mean-free-path that can be achieved in a two-dimensional electron gas confined at a GaAs/AlGaAs heterointerface.
Non-equilibrium electron scattering in n-type semiconductors
Authors: Levi A. F. J.
Published: September 2020

Following a brief introduction to quasiparticles and Landau Fermi-liquid theory, the experimental observation of non-equilibrium electron transport in n-type semiconductors is described. Next, the linear dielectric response of a Fermi sea of electrons to an external probe charge density is considered. The electron scattering rate is then calculated using the golden rule and the relative dielectric permittivity of the medium. The Lindhard electron susceptibility is evaluated consistent with Poisson's equation. As a worked example, the relative dielectric permittivity function for GaAs is obtained within the random phase approximation by adding the polarization response contributions from valence electrons, longitudinal polar-optic phonons, and the Fermi sea of conduction band electrons. The loss function shows the presence of two dispersive coupled plasmon–phonon modes. Analysis of non-equilibrium electron scattering rates at zero and finite temperature reveal the importance of kinematic constraints, the density of states, and quasiparticle occupation factors. The chapter concludes by considering the role of electron scattering rates in determining the optimal design of a unipolar n-type non-equilibrium electron transistor. The single-crystal epitaxially grown layered structure has a 10 nm thick base and abrupt heterointerfaces between emitter, base, and collector. Matching the electron group velocity either side of the base–collector heterointerface is found to be essential for efficient transistor operation.
Toward Quantum Engineering
Authors: Levi A. F. J.
Published: September 2020

This chapter briefly considers a future era when quantum engineering of new materials and device geometries, and a detailed understanding of quantum electron transport, will be needed to continue improving the performance of electronics as reduction in transistor minimum feature sizes comes to an end. Both the challenge of reducing subthreshold swing in transistors and the need for dense, very efficient, electrical interconnects are described. The unique behavior of memristor devices and opportunities for new back-end-of-line active devices is also discussed. The chapter concludes by introducing the concept of co-optimization between design and manufacture before and during circuit fabrication and novel paths to super-customization of systems and nano-scale electronic devices.
Economic and clinical outcomes of the nurse practitioner-led Sydney Adventist Hospital Community Palliative Care Service
Authors: Moreton Sam G. , Saurman Emily , Salkeld Glenn , Edwards Julie , Hooper Dawn , Kneen Kerrie , Rothwell Gillian , Watson John
Published: September 2020

ObjectiveThe aim of this study was to assess the clinical, economic and personal impacts of the nurse practitioner-led Sydney Adventist Hospital Community Palliative Care Service (SanCPCS)
MethodsParallel economic analysis of usual care was conducted prospectively with patients from the enhanced SanCPCS. A convenient retrospective sample from the initial service was used to determine the impact of the enhanced service on patient care. A time series survey was used with patients and carers from within the expanded service group in order to measure patient outcomes and values as they approached death.
ResultsPatients of the SanCPCS were less likely to die in hospital and had fewer hospital admissions. In addition, the service halved the estimated hospitalisation cost per patient, but the length of hospital stay was not affected by the service. The SanCPCS was more beneficial for women in terms of fewer hospital admissions and lower costs. Patients’ choices regarding place of care and death and what was ‘important’ to them changed over time. For instance, patients tended to prefer being at home as they approached death, and being pain free doubled in importance.
ConclusionsNurse practitioner-led community palliative care services have the potential to result in significant economic and personal benefits for patients and their families in need of such care.
What is known about the topic?National trends show an emphasis on community services with the aim of promoting and supporting the choice of dying at home, and this coincides with drives to reduce hospital costs and length of stay. Community-based palliative care services may offer substantial economic and clinical benefits.
What does this paper add?The SanCPCS was the first nurse practitioner-led community-based palliative care service in Australia. The expansion of this service led to significantly fewer admissions and deaths in hospital, and halved the estimated hospitalisation cost per patient.
What are implications for practitioners?Nurse practitioner-led models for care in the out-patient or community setting are a logical direction for palliative services through the engagement of specialised providers uniquely trained to support, nurture, guide and educate patients and their carers.
Agronomic management combining early-sowing on establishment opportunities, cultivar options and adequate nitrogen is critical for canola (Brassica napus) productivity and profit in low-rainfall environments
Authors: McBeath Therese , Meier Elizabeth A. , Ware Andrew , Kirkegaard John , Moodie Michael , Davoren Bill , Hunt Ed
Published: September 2020

Sustaining diverse, yet productive crop sequences that integrate break crops such as canola (Brassica napus L.) remains a critical challenge for farming systems in low-rainfall cropping environments. Recent advances in canola productivity through early sowing, understanding of critical stress periods, hybrid cultivars and improved nitrogen (N) fertilisation offer promise under many conditions but require careful adaptation for risky, low-rainfall environments. A series of eight experiments was implemented over four growing seasons (2015–18) in the low-rainfall environments of southern Australia to test combinations of sowing date, cultivar selection and N-management strategies. Simulation modelling extended the field experiment results, enabling a simple, whole-farm profit–risk analysis across growing season deciles. The aim was to identify combinations of practices where the potential production and risk were understood, thereby assisting management decisions in low-rainfall cropping systems. Earlier sowing (April) was generally beneficial but only where seasonal conditions led to successful establishment, meaning that the best fit for canola in low-rainfall environments is as an opportunity crop. A hybrid cultivar (triazine tolerant) did not provide a yield advantage in an early experiment, but productivity increases were measured with a modern hybrid cultivar (Clearfield) in a later experiment. Profit-risk analysis suggested that a yield advantage of >20% over open-pollinated cultivars needs to be sustained across the full range of season deciles to generate economic advantage. Although there was relative insensitivity to the timing of N application, an adequate dose of N, either through fertiliser or legume crops, was critical to improve canola productivity. We conclude that opportunities exist to make significant gains in yield (by up to 110% compared with current standard practice) and profit–risk outcomes (~30% increased gross margins across all season types) for canola in low-rainfall environments by using a package of agronomic management decisions that includes early sowing on genuine establishment opportunities, hybrids that offer sustained yield benefits, and matching N dose from both fertiliser and legume crops to yield potential of the soil type and seasonal outlook.
The cytoplasmic tail of human mannosidase Man1b1 contributes to catalysis-independent quality control of misfolded alpha1-antitrypsin
Authors: Sun Ashlee H. , Collette John R. , Sifers Richard N.
Published: September 2020

Significance

Defects in systems that orchestrate the intracellular clearance of misfolded proteins are implicated as central contributors to numerous human diseases. Our study has further elucidated the unexpected capacity for the prototype mannosidase, Man1b1, to target misfolded alpha1-antitrypsin for intracellular loss by an unconventional, N-glycan-independent manner. Identification of this functional dichotomy, and especially the Man1b1-mediated catalysis-independent system, might influence the design of future therapeutic interventions for selected conformational diseases of the secretory pathway.
The 17-y spatiotemporal trend of PM
2.5
and its mortality burden in China
Authors: Liang Fengchao , Xiao Qingyang , Huang Keyong , Yang Xueli , Liu Fangchao , Li Jianxin , Lu Xiangfeng , Liu Yang , Gu Dongfeng
Published: September 2020

Significance

Estimation of the chronic health effects of PM
2.5
exposure has been hindered by the lack of long-term PM
2.5
data in China. To support this, high-performance machine-learning models were developed to estimate PM
2.5
concentrations at 1-km resolution in China from 2000 to 2016, based on satellite data, meteorological conditions, land cover information, road networks, and air pollution emission indicators. By adopting imputation techniques, relatively unbiased spatiotemporally continuous exposure estimates were generated. Annual mortality burdens attributable to long-term PM
2.5
exposure were estimated at the provincial scale, and the national total adult premature deaths were estimated at 30.8 million over the 17-y period in China.
Ecological divergence and hybridization of Neotropical
Leishmania
parasites
Authors: Van den Broeck Frederik , Savill Nicholas J. , Imamura Hideo , Sanders Mandy , Maes Ilse , Cooper Sinclair , Mateus David , Jara Marlene , Adaui Vanessa , Arevalo Jorge , Llanos-Cuentas Alejandro , Garcia Lineth , Cupolillo Elisa , Miles Michael , Berriman Matthew , Schnaufer Achim , Cotton James A. , Dujardin Jean-Claude
Published: September 2020

Significance

Parasites are interesting models for studying speciation processes because they have a high potential for specialization, thanks to the intimate ecological association with their hosts and vectors. Yet little is known about the circumstances under which new parasite lineages emerge. Here we studied the genome diversity of parasites of the
Leishmania braziliensis
species complex that inhabit both Amazonian and Andean biotas in Peru. We identify three major parasite lineages that occupy particular ecological niches and show that these emerged during forestation changes over the past 150,000 y. We furthermore discovered that meiotic recombination between Amazonian and Andean lineages resulted in full-genome hybrids presenting mixed mitochondrial genomes, providing insights into the genetic consequences of hybridization in parasitic protozoa.
Structural determinants of protocadherin-15 mechanics and function in hearing and balance perception
Authors: Choudhary Deepanshu , Narui Yoshie , Neel Brandon L. , Wimalasena Lahiru N. , Klanseck Carissa F. , De-la-Torre Pedro , Chen Conghui , Araya-Secchi Raul , Tamilselvan Elakkiya , Sotomayor Marcos
Published: September 2020

Significance

When sound vibrations reach the inner ear, fine protein filaments called “tip links” stretch and open cochlear hair-cell mechanosensitive channels that trigger sensory perception. Similarly, vestibular hair cells use tip links to sense mechanical stimuli produced by head motions. Tip links are formed by cadherin-23 and protocadherin-15, two large proteins involved in hearing loss and balance disorders. Here we present multiple structures, models, and simulations that depict the lower end of the tip link, including the complete protocadherin-15 ectodomain. These models show an essential connection between cadherin-23 and protocadherin-15 with dual molecular “handshakes” and various protein sites that are mutated in inherited deafness. The simulations also reveal how the tip link responds to force to mediate hearing and balance sensing.
Chelicerata sDscam isoforms combine homophilic specificities to define unique cell recognition
Authors: Zhou Fengyan , Cao Guozheng , Dai Songjun , Li Guo , Li Hao , Ding Zhu , Hou Shouqing , Xu Bingbing , You Wendong , Wiseglass Gil , Shi Feng , Yang Xiaofeng , Rubinstein Rotem , Jin Yongfeng
Published: September 2020

Significance

Neuronal self-avoidance is a conserved process in vertebrates and invertebrates. In
Drosophila
, self-avoidance is mediated by the
Down syndrome cell adhesion molecule
(
Dscam1
) gene that encodes tens of thousands of proteins through alternative splicing. In vertebrates, an analogous function is performed by ∼60 clustered protocadherins (cPcdh) through promoter choice. Here we use cell aggregation assays to study the binding preferences of ∼100 sDscam protein in scorpion. We report that while related in sequence to the fly Dscam, the scorpion sDscam adopts a strategy that is similar to that of vertebrate cPcdhs, of combined specificity when coexpressed. Our findings identify sDscams as likely candidates to mediate neuronal self-avoidance in Chelicerata, as well as provide a remarkable example of convergent evolution.
The 3.6-Ma aridity and westerlies history over midlatitude Asia linked with global climatic cooling
Authors: Fang Xiaomin , An Zhisheng , Clemens Steven C. , Zan Jinbo , Shi Zhengguo , Yang Shengli , Han Wenxia
Published: September 2020

Significance

We recovered the world’s thickest continuous loess record from the southern margin of the Taklimakan desert, a global-scale dust source area. The continuous high-resolution grain size and flux records of dust emission, reflecting histories of aridity and westerlies climate, indicate an extant dry climate, desert area, and stable land surface supporting continuous loess deposition at least since ∼3.6 Ma, and that global cooling, rather than Tibet uplift, modulated the histories of aridity and westerlies climate changes in inland Asia since ∼3.6 Ma. Moreover, our study may suggest potential positive linkages and feedback among dust emission, marine biogeochemical activity, atmospheric CO
2
, and global cooling, which might provide insights into dynamics of Earth’s climate system and improve predictions for the future.
Vitamin D3 receptor polymorphisms regulate T cells and T cell-dependent inflammatory diseases
Authors: Fernandez Lahore Gonzalo , Raposo Bruno , Lagerquist Marie , Ohlsson Claes , Sabatier Pierre , Xu Bingze , Aoun Mike , James Jaime , Cai Xiaojie , Zubarev Roman A. , Nandakumar Kutty Selva , Holmdahl Rikard
Published: September 2020

Significance

Conclusive identification of single genes contributing to complex autoimmune diseases has been challenging. Here, we positionally identify the vitamin D3 receptor gene (
Vdr
) as a driver of T cell-dependent inflammatory diseases using forward genetics. In the process, we generated congenic mice that overexpress
Vdr
in T cells as a consequence of natural polymorphisms in its promoter. These mice present a unique opportunity to study the immunomodulatory properties of VDR in a physiological setting. Moreover, the restricted overexpression of VDR to immune cells allows discrimination between immune-acting and confounding musculoskeletal effects of VDR. Our results suggest that VDR plays a role in T cell activation in parallel to the antiinflammatory actions mediated by its ligand.
Vitamin A aldehyde-taurine adduct and the visual cycle
Authors: Kim Hye Jin , Zhao Jin , Sparrow Janet R.
Published: September 2020

Significance

Taurine is a sulfur-containing amino acid that is not incorporated into protein but is abundant in retina. Schiff base adducts that form nonenzymatically and reversibly from reactions between taurine and vitamin A aldehyde (A1T) are increased under conditions in which the visual chromophore 11-
cis
-retinal is more abundant. These settings include black versus albino mice, dark-adapted versus light-adapted mice, and mice expressing the Rpe65-Leu450 versus Rpe65-Met450 variant. Conversely, A1T is less abundant in mouse models deficient in 11-
cis
-retinal. As an amphiphile, protonated A1T may serve to facilitate retinoid trafficking and could constitute a small-molecule reserve of mobilizable 11-
cis
-retinal in photoreceptor cells.
Treatment of mental illness in American adolescents varies widely within and across areas
Authors: Cuddy Emily , Currie Janet
Published: September 2020

Significance

This study uses a large national database of insured adolescent children who have an initial insurance claim for a mental illness. Many of these children either fail to receive follow-up care within 3 mo, or receive care that appears to fall short of standard guidelines for the initial treatment of mental illness in children. The majority do not receive therapy, and many children receive drugs that raise a red flag, such as benzodiazepines, tricyclic antidepressants, and drugs that are not Food and Drug Administration-approved for use in children. Very little of the variation in these outcomes can be explained by shortages of mental health professionals.
Catch–quota matching allowances balance economic and ecological targets in a fishery managed by individual transferable quota
Authors: Oostdijk Maartje , Byrne Conor , Stefánsson Gunnar , Santos Maria J. , Woods Pamela J.
Published: September 2020

Significance

The trend toward individual quota and discard bans presents a challenge for mixed fisheries: how to avoid widespread underutilization of quota due to choking effects of individual species for which quota is exhausted. Iceland’s demersal fishery has met this challenge using the most elaborate set of balancing mechanisms in the world. We investigated the performance of the Icelandic system and find pervasive incentives inherent in the system’s design. The absence of persistent overfishing of individual stocks is attributed to limits that have been tightened over time and are very strict for the primary target species. These results highlight the potential for balancing mechanisms to facilitate sustainable exploitation of distinct interconnected resources and the importance of adapting implementation to local circumstances.
Transmission dynamics reveal the impracticality of COVID-19 herd immunity strategies
Authors: Brett Tobias S. , Rohani Pejman
Published: September 2020

Significance

Confronted with escalating COVID-19 outbreaks, countries at the leading edge of the pandemic have had to resort to imposing drastic social distancing measures which have serious societal and economic repercussions. Establishing herd immunity in a population by allowing the epidemic to spread, while mitigating the negative health impacts of COVID-19, presents a tantalizing resolution to the crisis. Our study simulating SARS-CoV-2 spread in the United Kingdom finds that achieving herd immunity without overwhelming hospital capacity leaves little room for error. Intervention levels must be carefully manipulated in an adaptive manner for an extended period, despite acute sensitivity to poorly quantified epidemiological factors. Such fine-tuning of social distancing renders this strategy impractical.
Circulating testican-2 is a podocyte-derived marker of kidney health
Authors: Ngo Debby , Wen Donghai , Gao Yan , Keyes Michelle J. , Drury Erika R. , Katz Dan H. , Benson Mark D. , Sinha Sumita , Shen Dongxiao , Farrell Laurie A. , Peterson Bennet D. , Friedman David J. , Elmariah Sammy , Young Bessie A. , Smith J. Gustav , Yang Qiong , Vasan Ramachandran S. , Larson Martin G. , Correa Adolfo , Humphreys Benjamin D. , Wang Thomas J. , Pollak Martin R. , Wilson James G. , Gerszten Robert E. , Rhee Eugene P.
Published: September 2020

Significance

All existing blood biomarkers of kidney function such as creatinine and cystatin C undergo renal clearance and are thus inversely correlated with estimated glomerular filtrate rate (eGFR). Using a proteomic approach, we highlight the renal release of testican-2 among individuals undergoing invasive catheterization and show that higher blood testican-2 levels are associated with higher eGFR and slower rate of subsequent eGFR decline in two large racially diverse cohorts. In conjunction with microscopy and single-cell RNA sequencing of human kidney samples, these studies advance the concept that a protein released by the podocyte can provide insight into the kidney’s health and prognosis. Cell-based studies also raise the possibility that this protein has functional effects on neighboring glomerular endothelial cells.
Endoplasmic reticulum chaperones stabilize ligand-receptive MR1 molecules for efficient presentation of metabolite antigens
Authors: McWilliam Hamish E. G. , Mak Jeffrey Y. W. , Awad Wael , Zorkau Matthew , Cruz-Gomez Sebastian , Lim Hui Jing , Yan Yuting , Wormald Sam , Dagley Laura F. , Eckle Sidonia B. G. , Corbett Alexandra J. , Liu Haiyin , Li Shihan , Reddiex Scott J. J. , Mintern Justine D. , Liu Ligong , McCluskey James , Rossjohn Jamie , Fairlie David P. , Villadangos Jose A.
Published: September 2020

Significance

A newly discovered system for immunological detection of diverse bacterial and fungal pathogens involves the MHC-like host protein called MR1. This molecule scavenges metabolites from the biosynthesis of riboflavin by microbes. MR1 presents these compounds on the surface of antigen-presenting cells, where they interact with T cells known as mucosal-associated invariant T cells and stimulate immunity. Critical aspects of the cell biology of metabolite presentation by MR1 are unknown. Here we generated a fluorescent antigen analog and use it to show that MR1 captures its metabolites within the endoplasmic reticulum. We describe proteins that maintain MR1 ready for metabolite binding in the endoplasmic reticulum to promote efficient pathogen detection. MR1 thus monitors extracellular microbial metabolites from within the cell.
Stick–slip model for actin-driven cell protrusions, cell polarization, and crawling
Authors: Sens Pierre
Published: September 2020

Significance

Spreading and crawling cells display rich nonlinear dynamics, which include periodic phases of growth and retraction of cellular protrusion, traveling waves along the cell edges, and spontaneous cell polarization and crawling. Using a theoretical model combining the mechanosensitivity of cell–substrate adhesion kinetics and linear cell viscoelastic mechanics, I show that the force-sensitive unbinding of adhesion bonds leads to stick–slip dynamics that recapitulate these dynamics’ features. The model also highlights the role of the cell membrane tension in controlling spontaneous symmetry breaking and the transition between spreading and crawling. This suggests that purely mechanical feedback loops, in addition to those involved in biochemical signaling networks, are key regulators of cell crawling.