bluuebunny/crossref_metadata_2025 huggingface dataset:
Blunt body impact onto viscoelastic floating ice plate with a soft layer on its upper surface
Authors: Khabakhpasheva T. I. , Korobkin A. A.
Published: June 2021

Two-dimensional vertical impact of a rigid blunt body onto a floating ice plate is studied. The problem is coupled and unsteady. The liquid is inviscid, incompressible, and of infinite depth. The ice floe is modeled as a thin viscoelastic plate of constant thickness. The plate edges are free of bending stresses and shear forces. The upper surface of the plate is covered with a viscoelastic layer of constant small thickness and negligible inertia. The reaction force of this soft layer is predicted by a nonlinear and one-dimensional Winkler-Kelvin-Voigt model, which does not permit a contact between the rigid body and the ice plate. The soft layer may describe either the presence of snow on the ice or a layer of crushed ice in the place of impact, or can be considered as a way of regularization of problems with concentrated loads. The rigid body touches the upper surface of the soft layer and then suddenly starts to move downward with constant velocity. It is shown that the strains in the ice plate caused by the impact are weakly dependent on the characteristics of the soft layer. The magnitudes and distributions of the strains are studied depending on the length of the ice plate, retardation time of the ice model, thickness of the plate, shape of the rigid body, place of impact, and the impact speed. The value of the retardation time in the soft layer model is discussed with relation to the ice crushing by impact.
Tuning growth of MoS2 nanowires over NiTiCu nanostructured array for flexible supercapacitive electrodes with enhanced Li-ion storage
Authors: Ranjan Bhanu , Sharma Gagan Kumar , Kaur Davinder
Published: June 2021

Rationally engineered three-dimensional (3D) clusters of MoS2 nanowires vertically anchored over a nanostructured NiTiCu shape memory alloy are fabricated using magnetron sputtering for flexible thin film supercapacitive electrodes. The heterostructure MoS2/NiTiCu deposited directly over flexible stainless steel (SS) offers remarkable electrochemical performance along with excellent mechanical stability, arising synergistically from the large specific surface of MoS2 nanowires and a high mechanical strength of NiTiCu@SS. The electrochemical studies in sulfate electrolytes (Li2SO4 and Na2SO4) manifest dominant charge transport efficiency of Li+ into the easily accessible electroactive sites of MoS2. The electrode delivers a superior gravimetric capacitance (379.25 F/g at 0.78 A/g) in addition to outstanding cycling stability (95.9% over 5000 cycles), suggesting high Li+ conductivity, low equivalent series resistance, and good substrate adhesion. Furthermore, the Power law and Dunn's approach reveal that charge storage into the highly porous MoS2 networks occurs mainly through the pseudocapacitive mechanism in Li2SO4 and capacitive processes in Na2SO4. Practically flexing the working electrode over 1000 bending cycles degrades the capacitance by only 17.17%, achieving highly desirable mechanical stability. Significantly, a superior power density of 12.54 kW/kg, while simultaneously achieving a high energy density of 52.67 Wh/kg, presents the electrode's immense potential for high-performance supercapacitor devices in flexible electronics.
Polymer brush-induced depletion interactions and clustering of membrane proteins
Authors: Tom Anvy Moly , Kim Won Kyu , Hyeon Changbong
Published: June 2021

We investigate the effect of mobile polymer brushes on proteins embedded in biological membranes by employing both Asakura–Oosawa type of theoretical model and coarse-grained molecular dynamics simulations. The brush polymer-induced depletion attraction between proteins changes non-monotonically with the size of brush. The depletion interaction, which is determined by the ratio of the protein size to the grafting distance between brush polymers, increases linearly with the brush size as long as the polymer brush height is shorter than the protein size. When the brush height exceeds the protein size, however, the depletion attraction among proteins is slightly reduced. We also explore the possibility of the brush polymer-induced assembly of a large protein cluster, which can be related to one of many molecular mechanisms underlying recent experimental observations of integrin nanocluster formation and signaling.
Highly efficient one-photon upconversion with cooperative enhancements of photon and phonon absorption in chlorophyll plexciton hybrids
Authors: Ding Si-Jing , Ma Liang , Zhou Tao , Yang Da-Jie , Nan Fan , Zhou Li , Wang Qu-Quan
Published: June 2021

We have demonstrated greatly enhanced light harvesting and one-photon upconversion in the plexcitonic hybrids of chlorophyll molecules strongly coupled to silver nanoparticles. The enhancement factors of the instantaneous and time-average upconversion intensity of the hybrids reached maxima of 36.2 and 28.5, respectively. Furthermore, the power and temperature dependences as well as the excitation and emission dynamics of upconversion were systematically investigated, revealing that highly efficient upconversion is predominantly attributable to the one-photon anti-Stokes process. The photon and phonon absorption processes are cooperatively enhanced by plexciton resonance. Additionally, coherent plexcitonic Rabi oscillations and plexciton-enhanced triplet–triplet annihilation are also discussed.
Engineered nanoparticle network models for autonomous computing
Authors: Wei Xingfei , Zhao Yinong , Zhuang Yi , Hernandez Rigoberto
Published: June 2021

Materials that exhibit synaptic properties are a key target for our effort to develop computing devices that mimic the brain intrinsically. If successful, they could lead to high performance, low energy consumption, and huge data storage. A 2D square array of engineered nanoparticles (ENPs) interconnected by an emergent polymer network is a possible candidate. Its behavior has been observed and characterized using coarse-grained molecular dynamics (CGMD) simulations and analytical lattice network models. Both models are consistent in predicting network links at varying temperatures, free volumes, and E-field (E⃗) strengths. Hysteretic behavior, synaptic short-term plasticity and long-term plasticity—necessary for brain-like data storage and computing—have been observed in CGMD simulations of the ENP networks in response to E-fields. Non-volatility properties of the ENP networks were also confirmed to be robust to perturbations in the dielectric constant, temperature, and affine geometry.
Axially overlapped multi-focus light sheet with enlarged field of view
Authors: Li Hongjin , Wu Zihan , Yang Zhichao , Zhanghao Karl , Xi Peng , Jin Dayong
Published: June 2021

Light sheet fluorescence microscopy provides optical sectioning and is widely used in volumetric imaging of large specimens. However, the axial resolution and the lateral Field of View (FoV) of the system, defined by the light sheet, typically limit each other due to the spatial band product of the excitation objective. Here, we develop a simple multi-focus scheme to extend the FoV, where a Gaussian light sheet can be focused at three or more consecutive positions. Axially overlapped multiple light sheets significantly enlarge the FoV with improved uniformity and negligible loss in axial resolution. By measuring the point spread function of fluorescent beads, we demonstrated that the obtained light sheet has a FoV of 450 μm and a maximum axial FWHM of 7.5 μm. Compared with the conventional single-focus one, the multi-focus Gaussian light sheet displays a significantly improved optical sectioning ability over the full FoV when imaging cells and zebrafish.
Spin control using chiral templated nickel
Authors: Mishra Suryakant , Pasquali Luca , Fontanesi Claudio
Published: June 2021

This Letter reports an original spin valve device that is based on a chiral templated nickel material. Chirality in Ni is induced by exploiting co-electrodeposition of an organic chiral template. In this specific case, the chiral templating is enantiopure tartaric acid (TA). Facile electrodeposition (co-deposition) in ambient conditions produces a nickel chiral-templated material. Z-shaped magnetoresistance curves, switching sign as a function of TA handedness, prove the peculiar ferromagnetic character induced by the presence of a chiral compound. Synchrotron measurements using circular polarized light, x-ray natural circular dichroism, confirm the chirality of the Ni in the TA/Ni composite. Density functional theory calculation proves the existence of a strong electronic delocalization involving the tartaric acid and Ni. The significant finding of this Letter is that chiral templated Ni paves the way for future spin valve, which will be able to control the spin without an external magnetic field (as indeed foreseen within the chiral induced spin selectivity-effect framework).
Highly accurate energies of a plasma-embedded hydrogen atom in a uniform magnetic field
Authors: Ly Duy-Nhat , Hoang Ngoc-Tram D. , Le Van-Hoang
Published: June 2021

The energy spectrum of a hydrogen atom in a plasma has been of interest in physics until now. This problem is also quite important for astrophysics when considering the system in a magnetic field. This work suggests a method for numerically solving the Schrödinger equation of a plasma-embedded hydrogen atom in a uniform magnetic field using a more generalized exponential cosine screened Coulomb potential (MGECSC). The first special feature of the method is to convert the problem into an anharmonic oscillator by using the Kustaanheimo–Stiefel transformation. The second one is to exactly calculate the matrix elements concerning the harmonic oscillator basis set. These allow us to apply the Feranchuk–Komarov operator method to the Schrödinger equation for obtaining numerical solutions converging to any given precision. In this work, we obtain energies with a record precision of up to 30 decimal places for the ground and highly excited states with the principal quantum number up to n = 10. We test the FORTRAN program for a wide range of the magnetic field up to 10 a.u. (2.35×106 T), exceeding the threshold in the neutron stars. Also, the program works well with the range of the screening parameters describing the plasma environment in the previous theoretical and experimental studies. Apart from energies, the program also provides the corresponding wave functions. The results are meaningful not only for the development of methods but also for physics analysis and benchmarks for other approximate methods.
stk: An extendable Python framework for automated molecular and supramolecular structure assembly and discovery
Authors: Turcani Lukas , Tarzia Andrew , Szczypiński Filip T. , Jelfs Kim E.
Published: June 2021

Computational software workflows are emerging as all-in-one solutions to speed up the discovery of new materials. Many computational approaches require the generation of realistic structural models for property prediction and candidate screening. However, molecular and supramolecular materials represent classes of materials with many potential applications for which there is no go-to database of existing structures or general protocol for generating structures. Here, we report a new version of the supramolecular toolkit, stk, an open-source, extendable, and modular Python framework for general structure generation of (supra)molecular structures. Our construction approach works on arbitrary building blocks and topologies and minimizes the input required from the user, making stk user-friendly and applicable to many material classes. This version of stk includes metal-containing structures and rotaxanes as well as general implementation and interface improvements. Additionally, this version includes built-in tools for exploring chemical space with an evolutionary algorithm and tools for database generation and visualization. The latest version of stk is freely available at github.com/lukasturcani/stk.
Nonreciprocity and isolation induced by an angular momentum bias in convection-diffusion systems
Authors: Xu Liujun , Huang Jiping , Ouyang Xiaoping
Published: June 2021

Inspired by the electronic and acoustic Zeeman effects in wave systems, we demonstrate here that an angular momentum bias generated by a volume force can also lead to modal splitting in convection-diffusion systems but with different features. We further reveal the thermal Zeeman effect by studying the temperature propagation in an angular-momentum-biased ring with three ports (one for input and two for output). In the presence of an optimal volume force, temperature propagation is allowed at one output port but isolated at the other, so rectification coefficient can reach a maximum value of 1. The volume forces corresponding to rectification coefficient peaks can also be predicted by scalar (i.e., temperature) interference quantitatively. Compared with existing mechanisms of thermal nonreciprocity, an angular momentum bias does not require temperature-dependent and phase-change materials, which has an advantage in wide-temperature-range applicability. These results may provide insights into thermal stabilization and thermal topology. The related mechanism is also general for other convection-diffusion systems such as mass transport, chemical mixing, and colloid aggregation.
Enhanced far ultraviolet spectral response and gain in SiC avalanche photodiodes
Authors: Sampath A. V. , Chen Y. , Llopis A. , Shen H. , Smith J. , Kelley S. , Schuster J. , Nouketcha F. , Campbell J. C. , Wraback M.
Published: June 2021

The voltage dependent spectral response in the 200–400 nm range was measured in n+-n--p SiC avalanche photodiodes with ultrathin n+ layers varying in the thickness from 60 to 120 nm. The unity gain responsivity in the far ultraviolet (200–250 nm) spectral region increases significantly with bias, leading to a 2–3 times enhancement at 200 nm for devices with 120 nm and 60 nm n+ layers, respectively. At the onset of gain, new spectral response peaks appear at 226 nm and 240 nm for the devices with the 60 nm and 120 nm thick n+ layers, respectively, both significantly blue shifted from the zero bias peak at 265 nm. Modeling indicates that the enhanced far ultraviolet unity gain responsivity results from the improved collection of carriers photogenerated near the illuminated surface of the device as the depletion of the n-region extends toward the surface, thereby mitigating surface recombination. The emergence of the peaks at higher bias and their larger blue shift with decreasing n+ layer thickness can be explained by the longer transit distance across the multiplication region for the holes with improved collection photogenerated near the illuminated surface, which leads to a larger enhancement in a multiplication gain with increasing bias for 200 nm photoexcitation over that for 380 nm. Devices employing the thicker 120 nm n+ layer achieve a multiplication gain greater than 5 × 106 at 12 pW 240 nm illumination, and ∼ 12 nA/cm2 dark current at gain of 1000 suitable for single photon counting.
Perspective on the future of silicon photonics and electronics
Authors: Margalit Near , Xiang Chao , Bowers Steven M. , Bjorlin Alexis , Blum Robert , Bowers John E.
Published: June 2021

Silicon photonics is advancing rapidly in performance and capability with multiple fabrication facilities and foundries having advanced passive and active devices, including modulators, photodetectors, and lasers. Integration of photonics with electronics has been key to increasing the speed and aggregate bandwidth of silicon photonics based assemblies, with multiple approaches to achieving transceivers with capacities of 1.6 Tbps and higher. Progress in electronics has been rapid as well, with state-of-the-art chips including switches having many tens of billions of transistors. However, the electronic system performance is often limited by the input/output (I/O) and the power required to drive connections at a speed of tens of Gbps. Fortunately, the convergence of progress in silicon photonics and electronics means that co-packaged silicon photonics and electronics enable the continued progress of both fields and propel further innovation in both.
Dripping and jetting of semi-dilute polymer solutions co-flowing in co-axial capillaries
Authors: Vagner S. A. , Patlazhan S. A. , Serra C. A. , Funfschilling D. , Kulichikhin V. G.
Published: June 2021

This work is focused on the mechanisms of the dripping and jetting flow modes of viscoelastic semi-dilute polyacrylamide aqueous solutions co-flowing with silicone oil in co-axial capillaries. A phase diagram of the dripping, jetting, and intermediate flow modes is established. It was found that in the dripping mode, the elongation velocity of the filament between the terminal droplet and the inner capillary is controlled solely by the continuous phase rate. At the same time, the decrease in the filament diameter is due to both stretching and outflow of the polymer solution into the terminal droplet. In the jetting mode, the thread diameter was found to evolve in three stages. In the first stage, the average jet velocity increases, whereas in the second and third stages, it becomes constant and corresponds to the velocity of the continuous phase. The transition from the second to the third stage is defined by the appearance of capillary waves resulting in the formation of the beads-on-string structure. In the third stage, the filament diameter between the neighbor beads decreases exponentially and is governed by the relaxation time, which strongly depends on polymer concentration, but does not depend on the continuous phase flow rate. A simple physical model was proposed for describing the evolution of dimensions of filaments and beads during development of jet capillary instability. The universal character of the evolution of filaments and beads sizes, which is independent of concentration of semi-diluted polymer solutions and flow rates of the continuous phase, is revealed.
2DEGs formed in AlN/GaN HEMT structures with AlN grown at low temperature
Authors: Reilly Caroline E. , Hatui Nirupam , Mates Thomas E. , Nakamura Shuji , DenBaars Steven P. , Keller Stacia
Published: June 2021

Integration of nitrides with other material systems has recently become of interest due to the high performance of GaN-based high-electron mobility transistors. However, the elevated growth temperatures often used to grow high quality AlN pose challenges toward metalorganic chemical vapor deposition (MOCVD) on temperature sensitive substrates such as processed wafers. In this work, the growth of AlN was conducted at temperatures below 550 °C via MOCVD using a flow-modulated epitaxy scheme, and their morphological, compositional, and electronic properties of these films were investigated. Sheet charges up to 2.1 × 1013 cm−2 and mobilities on the order of 400 cm2/V s were measured for two dimensional electron gases, which formed at the interface between the low temperature grown AlN layers and the semi-insulating GaN base layers deposited at high temperatures. Despite their low growth temperatures, nominally pure AlN barrier layers exhibited measurable unintentional gallium incorporation adjacent to the GaN interface. The result sets the stage for the integration of nitride-based electronics via epitaxy-based schemes on temperature sensitive substrates.
Quasi-phasematching in a poled Josephson traveling-wave parametric amplifier with three-wave mixing
Authors: Zorin A. B.
Published: June 2021

We develop the concept of quasi-phasematching (QPM) by implementing it in the recently proposed Josephson traveling-wave parametric amplifier (JTWPA) with three-wave mixing (3WM). The amplifier is based on a ladder transmission line consisting of flux-biased radio frequency superconducting quantum interference devices (SQUIDs) whose nonlinearity is of χ(2)-type. QPM is achieved in the 3WM process, ωp=ωs+ωi (where ωp, ωs, and ωi are the pump, signal, and idler frequencies, respectively) due to designing the JTWPA to include periodically inverted groups of these SQUIDs that reverse the sign of the nonlinearity. Modeling shows that the JTWPA bandwidth is relatively large (∼ 0.4ωp) and flat, while unwanted modes, including ω2p=2ωp, ω+=ωp+ωs, and ω−=2ωp−ωs, are strongly suppressed with the help of engineered dispersion.
Electrohydrodynamic disintegration of dielectric fluid blended with ethanol
Authors: Xu Haojie , Wang Junfeng , Tian Jiameng , Li Bin , Yao Jiang , Zuo Lei , Zhang Yan , Zhao Tianyue
Published: June 2021

Engineered fluid HFE-7100 is an outstanding detergent and coolant with excellent thermal and chemical stability. Electrohydrodynamic jet disintegration and subsequent droplet formation of HFE-7100 dielectric liquid mixed with ethanol were experimentally investigated in this study. Contact-type charging was employed with the capillary nozzle directly connected to a negative high-voltage power supply, while the counter electrode was grounded. High-speed photography was utilized to capture the liquid breakup and droplet formation behaviors. The results showed that an ethanol content of 8% by volume visibly improved the charging performance of HFE-7100 due to the increase in the liquid electrical conductivity. In addition, with the increase in the applied voltage, the jet breakup was found to transform from the dripping/jetting mode to the ramified mode, which is characterized by a steady liquid sheet with fine droplets forming at the edge. Two distinct ramified breakup configurations, called the pudgy-ramified and lanky-ramified modes, are proposed, and their detailed structural parameters and droplet size distributions are discussed. The diameters of the droplets produced under the permanent ramified configuration could be as small as a few micrometers. Finally, a jet breakup regime map based on the Reynolds number Re and electric bond number BoE was established. Overall, the electrospray technique has shown promise for spray cooling enhancement, and the main results of this paper may be useful for the development of electrospray cooling with a dielectric coolant.
Optical two-dimensional coherent spectroscopy of many-body dipole–dipole interactions and correlations in atomic vapors
Authors: Liang Danfu , Li Hebin
Published: June 2021

Many-body interactions and correlations in atomic ensembles are fundamental in understanding many-body effects such as collective and emergent phenomena and also play an important role in various atom-based applications. Optical two-dimensional coherent spectroscopy (2DCS) provides a powerful tool to measure many-body interactions and correlations. Here, we present the study of many-body dipole–dipole interactions and correlations in potassium and rubidium atomic vapors by using double-quantum and multi-quantum 2DCS. The results show that double-quantum 2DCS provides sensitive and background-free detection of weak dipole–dipole interaction between atoms with a mean separation up to about 16 μm, and multi-quantum 2DCS can excite and detect multi-atom states (Dicke states) with up to eight correlated atoms. The technique of optical 2DCS can provide a new approach to study many-body physics in atomic ensembles and can be potentially implemented to measure many-body effects in cold atoms and other atomic/molecular systems.
An exact a posteriori correction for hydrogen bond population correlation functions and other reversible geminate recombinations obtained from simulations with periodic boundary conditions. Liquid water as a test case
Authors: Busch Johanna , Neumann Jan , Paschek Dietmar
Published: June 2021

The kinetics of breaking and re-formation of hydrogen bonds (HBs) in liquid water is a prototype of reversible geminate recombination. HB population correlation functions (HBPCFs) are a means to study the HB kinetics. The long-time limiting behavior of HBPCFs is controlled by translatoric diffusion and shows a t−3/2 time-dependence, which can be described by analytical expressions based on the HB acceptor density and the donor–acceptor inter-diffusion coefficient. If the trajectories are not properly “unwrapped,” the presence of periodic boundary conditions (PBCs) can perturb this long-time limiting behavior. Keeping the trajectories “wrapped,” however, allows for a more efficient calculation of HBPCFs. We discuss the consequences of PBCs in combination with “wrapped” trajectories following from the approximations according to Luzar–Chandler and according to Starr, each deviating in a different fashion from the true long-time limiting behavior, but enveloping the unperturbed function. A simple expression is given for estimating the maximum time up to which the computed HBPCFs reliably describe the long-time limiting behavior. In addition, an exact a posteriori correction for systems with PBCs for “wrapped” trajectories is derived, which can be easily computed and which is able to fully recover the true t−3/2 long-time behavior. For comparison, HBPCFs are computed from MD simulations of TIP4P/2005 model water for varying system sizes and temperatures of 273 and 298 K using this newly introduced correction. Implications for the computations of HB lifetimes and the effect of the system-size are discussed.
Study on heat transfer characteristics of hollow composite thermal barrier structure at high temperature
Authors: Liu Yingjie , Liao Xiangwei , Shen Minggang , Zhu Xiaolei , Liu Kun
Published: June 2021

Air interlayers are often used as a part of thermal insulation structure and form a system with solid materials to reduce heat transfer. However, the heat transfer process in the composite structure is affected by many factors at high temperatures. In this paper, a series of heat preservation systems with air gap and solid structure were proposed. Based on the research background of heat preservation in the riser of ingot casting, the heat transfer process in the composite structure was systematically studied by means of numerical simulation and experiment. The heat transfer laws under different geometric structures, thermophysical properties of materials, and surface emissivity were obtained, which could provide theoretical basis for the design of heat preservation structures at high temperatures.
A constitutive analysis of stress overshoot for polymer melts under startup shear flow
Authors: Tseng Huan-Chang
Published: June 2021

Predicting a transient stress overshoot for polymer melts under startup shear flow is challenging. In recent, the classical White–Metzner (WM) constitutive equation of nonlinear viscoelastic fluids was potentially extended. For viscoelastic material functions, the minus ratio of the second normal stress difference to the first normal stress difference (−N2/N1) is important in characterizing a fluid's elasticity related to molecular structures and molecular weight distribution. Using the extended WM model to analyze a dramatic change in stress overshoot with respect to the −N2/N1 ratio at high Weissenberg numbers would be significant. As a validation, numerical predictions of shear stress growth coefficient at different shear rates are in good agreement with experimental data.
Multiscale modeling of tip-leakage cavitating flows by a combined volume of fluid and discrete bubble model
Authors: Li Linmin , Wang Zhengdong , Li Xiaojun , Zhu Zuchao
Published: June 2021

For the tip-leakage cavitating flow, the existence of both interface and microbubbles at scales separated by orders of magnitude makes it difficult to be comprehensively reproduced by numerical modeling. This work aims to develop a multiscale model that directly resolves the large-scale cavities and models small discrete bubbles. The volume of fluid (VOF) method and the Schnerr–Sauer cavitation model are first adopted to represent the phase field of water and vapor from a macroscale point of view. A discrete bubble model (DBM) based on the Lagrangian formulation is then developed to simulate the microscale cavitation bubbles that are smoothed in the macroscale model due to the limited mesh resolution. The transition between DBM and VOF is also implemented to achieve the multiscale simulation. For modeling of the turbulence, the scale adaptive simulation approach is used. The tip-leakage cavitating flows induced by the NACA0009 hydrofoil under the conditions with different gaps according to the reported experiment are simulated. Results show that, using the proposed multiscale model, better agreements can be obtained compared with the macroscale model, and specific phenomena can be well revealed including the bubble nucleation, growth and collapse, the interaction between discrete bubbles and large-scale cavities.
Case study of a stepped-care psychological service for healthcare professionals working in critical care
Authors: Galati Connie , Avard Bronwyn , Ramsay Louise
Published: June 2021

Psychological injury is common among healthcare professionals and is expected to be further exacerbated by the current global pandemic, with the far-reaching impacts of this workplace trauma yet to be fully realised. Our Intensive Care Unit and Emergency Department sought to proactively introduce strategies that might reduce the anticipated short- and longer-term negative impact of the pandemic on staff and ultimately patients and families. Our organisation facilitated the temporary redeployment of senior psychologists to provide staff-focused support. Interventions included leader targeted training to increase the skills in this group, specifically for this situation, and site visits to allow for staff to meet with psychologists. Staff experiences of the intervention were explored through the direct observations of the psychologists leading the approach maintained through contemporaneous activity tracking records. An internal and embedded staff psychological service fosters help-seeking behaviours and is considered a desirable and acceptable model for healthcare leaders and professionals. What is known about the topic? Healthcare professionals are at increased risk of psychological distress and injury caused by the inherent stress of their role. What does this paper add? This paper provides service providers with insights into the benefits of an embedded staff psychological service to support the psychological wellbeing of healthcare professionals and teams within an Australian public health service context. What are the implications for practitioners? An embedded staff psychological service can better meet the psychological needs of healthcare professionals and teams by focusing on prevention and early intervention strategies through targeted and tailored systems, teams, and individual interventions.
Glia-derived temporal signals orchestrate neurogenesis in the
Drosophila
mushroom body
Authors: Yang Mengying , Wang Honglei , Chen Changyan , Zhang Shiping , Wang Mengxiao , Senapati Bhagyashree , Li Shuhua , Yi Shuanglong , Wang Linfang , Zhang Min , Yin Shuai , He Yijing , Xue Lei , Lin Suewei , Ho Margaret S.
Published: June 2021

Significance

Brain function relies on tasks executed by different types of neurons generated via diverse mechanisms. Combining a series of genetic, cellular, and behavioral approaches, we identify a two-step glia-to-neuron signal that regulates how neurons are produced in the
Drosophila
mushroom body, a key learning center for animal behavior. This glial signal requires the action of an E3 ubiquitin ligase dSmurf that regulates the stability of two downstream effectors: the Hedgehog receptor Patched and the cell-adhesion molecule Fasciclin II. Our findings demonstrate the significance of glial cells in regulating neuron production, hence the brain function and animal behavior.
Differential immune imprinting by influenza virus vaccination and infection in nonhuman primates
Authors: McCarthy Kevin R. , Von Holle Tarra A. , Sutherland Laura L. , Oguin Thomas H. , Sempowski Gregory D. , Harrison Stephen C. , Moody M. Anthony
Published: June 2021

Significance

Immune memory causes the earliest infection by influenza virus to impart a lasting imprint on an individual’s response to later influenza infections or vaccinations. Until recently, that first exposure was always an infection. In the United States and Europe, many infants and toddlers now receive an influenza vaccine before they experience an infection. Because we have little information about immune imprinting by initial exposure to a vaccine, we have studied, in a nonhuman-primate model, how the mode of initial exposure affects primary and secondary antibody responses. Vaccination with influenza hemaglutinnin (HA) protein and infection with a strain bearing the same HA appear to leave distinct imprints—a difference, if confirmed in humans, relevant for next-generation influenza vaccine design.
Youngia japonica (oriental false hawksbeard).
Authors: Rojas-Sandoval Julissa
Published: June 2021

Youngia japonica is a cosmopolitan herb that often grows as an agricultural and environmental weed. Native to temperate and tropical Asia and Australia, it has been introduced in Africa, the Canary Islands, the Americas and many Pacific Islands. It is commonly found in disturbed areas, wastelands, roadsides, abandoned pastures, lawns, cultivated fields and forest margins, but it is also able to penetrate into intact or minimally-disturbed natural areas. This species is a prolific seed producer and its seeds can be easily dispersed by wind and water or as contaminant in soil or crop and grass seeds. Y. japonica is adapted to grow in a wide range of climates and substrates and once it reaches a new area, it grows and spreads very quickly as new seeds are produced copiously.
Cucurbit aphid-borne yellows virus (cucurbit aphid-borne yellows).
Authors: Lecoq Hervé , Desbiez Cécile , Schoeny Alexandra
Published: June 2021

Cucurbit aphid-borne yellows virus (CABYV) was first isolated in southern France in 1988. It causes, mostly in cucurbits, more or less severe yellowing diseases according to the season and cultivar. CABYV infects several weed species and is readily transmitted in a persistent manner by ubiquitous aphids that provide an efficient means of invasiveness worldwide. Symptoms of CABYV are similar to other biotic or abiotic disorders and dating first occurrences of the virus was difficult until appropriate diagnostic methods were developed. There is evidence that CABYV is becoming more frequent in areas where it was reported earlier (France, Spain and parts of Asia) and that it might have been recently introduced into new areas (Northern Europe, South America). Therefore, CABYV may be considered as potentially invasive both in places where it has not yet been reported and where it is already present. CABYV is not regulated or on an alert list.
Candidatus Phytoplasma phoenicium.
Authors: Quaglino Fabio
Published: June 2021

Phytoplasmas are wall-less parasitic bacteria living exclusively in plant phloem as consequence of transmission by sap-sucking insect vectors (Lee et al., 2000); they have been associated with several hundred plant diseases. 'Candidatus Phytoplasma phoenicium' (CaPphoe), subgroup 16SrIX-B, is the aetiological agent of almond witches'-broom (AlmWB), a severe disease affecting almond, peach and nectarine trees in Lebanon and Iran. The first epidemics of AlmWB occurred in almond trees in Lebanon in the early 1990s and in Iran in 1995. In Lebanon, the disease rapidly spread from coastal to high mountainous areas, killing almost 150,000 trees over a period of 15 years. CaPphoe was first added to the EPPO Alert List in 2001 and removed from the list in 2006. The more recent rapid spread of CaPphoe in peach and nectarine orchards and in other plant hosts, along with the identification of efficient insect vectors, increased the alarm about the risk it poses for stone fruit production in the Middle East and in all the countries of the Mediterranean basin. Thus it was re-inserted in the EPPO Alert List in 2015.
Cotton leaf curl disease complex (leaf curl disease of cotton).
Authors: Brown Judith K.
Published: June 2021

Leaf curl disease of cotton caused by the CLCuD-complex of begomoviruses is endemic to Pakistan and India and perhaps other nearby locales in south Asia. It has been introduced from there to China and the Philippines on ornamental plants, from where it has spread to infect cotton and okra in China. Losses are difficult to assess, but early estimates (pre-1990) range up to 20% when infection occurs early in the growing season and/or with highly susceptible cultivars Viruliferous whiteflies on infested/infected plants harbouring CLCuD-begomoviruses imported to other cotton-growing countries, in particular, are of concern in preventing introduction under optimal circumstances. No seed transmission is known to occur.
Cucumber green mottle mosaic virus.
Authors: Webster Craig , Jones Roger
Published: June 2021

CGMMV is a species of virus in the genus Tobamovirus, which was first described in 1935 in England. Between 1935 and 1985 it spread slowly to other countries, but faster between 1986 and 2006, and rapidly between 2007 and 2018. It now occurs on all continents except South America. In cucurbits, it causes a damaging disease that reduces fruit yields and quality and spreads efficiently by plant-to-plant contact transmission. Outbreaks occur in many cucurbit crops including vegetables and fruits (e.g. squash and melons). CGMMV seed transmission occurs in at least nine different cucurbit crop species and this is the main way the virus has spread worldwide. Importation of contaminated seeds constitutes a considerable biosecurity concern for counties still without CGMMV. Its high stability and its persistence in contaminated plant material and soil allow it to survive between growing seasons, making eradication difficult.
Xanthomonas vasicola pv. vasculorum (bacterial leaf streak of corn).
Authors: Triplett Lindsay , Patel Ravikumar
Published: June 2021

Xanthomonas vasicola pv. vasculorum (Xvv) is a bacterial pathogen that causes both bacterial leaf streak of maize and sugarcane gumming disease. After decades limited to South Africa, bacterial leaf streak of maize spread rapidly through maize-growing areas of Argentina, Brazil and the USA since 2014. The origin, method and biological underpinnings of this sudden spread are not well understood but are the subject of active research. Effective control methods remain elusive, but sanitation and crop debris management may limit the disease. Yield impact data are not yet available, but lesions may become severe enough to limit plant productivity in some varieties. The pathogen is not currently considered a quarantine threat by the USDA, EPPO or IPPC. Taxonomic Tree Top of page Domain: Bacteria Phylum: Proteobacteria Class: Gammaproteobacteria Order: Xanthomonadales Family: Xanthomonadaceae Genus: Xanthomonas Species: Xanthomonas vasicola pv. vasculorum Notes on Taxonomy and Nomenclature Top of page The taxonomic nomenclature of the pathogen has undergone several changes and is still being resolved at the time of this report. The Xanthomonas clade causing.
The longhorn beetle
Jebusaea hammerschmidtii
Reiche (Coleoptera: Cerambycidae): an old serious pest undermining date palm plantations
Authors: El-Shafie Hamadttu A.F.
Published: June 2021

The longhorn date palm stem borer,
Jebusaea hammerschmidtii
Reiche has become an important pest that causes economic damage in date palm groves. The beetle has established itself in many date palm-producing countries as one of the most important biotic factors that threatens date palm cultivation and genetic diversity. The larvae of the longhorn stem borer, the destructive stage, are endophytic developing inside the date palm tissues. This article consolidates the scant literature on the beetle biology, ecology, economic impact, possible field management measures, and future research priorities.
Mutation of a conserved glutamine residue does not abolish desensitization of acid-sensing ion channel 1
Authors: Rook Matthew L. , Miaro Megan , Couch Tyler , Kneisley Dana L. , Musgaard Maria , MacLean David M.
Published: June 2021

Desensitization is a common feature of ligand-gated ion channels, although the molecular cause varies widely between channel types. Mutations that greatly reduce or nearly abolish desensitization have been described for many ligand-gated ion channels, including glutamate, GABA, glycine, and nicotinic receptors, but not for acid-sensing ion channels (ASICs) until recently. Mutating Gln276 to a glycine (Q276G) in human ASIC1a was reported to mostly abolish desensitization at both the macroscopic and the single channel levels, potentially providing a valuable tool for subsequent studies. However, we find that in both human and chicken ASIC1, the effect of Q276G is modest. In chicken ASIC1, the equivalent Q277G slightly reduces desensitization when using pH 6.5 as a stimulus but desensitizes, essentially like wild-type, when using more acidic pH values. In addition, steady-state desensitization is intact, albeit right-shifted, and recovery from desensitization is accelerated. Molecular dynamics simulations indicate that the Gln277 side chain participates in a hydrogen bond network that might stabilize the desensitized conformation. Consistent with this, destabilizing this network with the Q277N or Q277L mutations largely mimics the Q277G phenotype. In human ASIC1a, the Q276G mutation also reduces desensitization, but not to the extent reported previously. Interestingly, the kinetic consequences of Q276G depend on the human variant used. In the common G212 variant, Q276G slows desensitization, while in the rare D212 variant desensitization accelerates. Our data reveal that while the Q/G mutation does not abolish or substantially impair desensitization as previously reported, it does point to unexpected differences between chicken and human ASICs and the need for careful scrutiny before using this mutation in future studies.
Modeling and measurement of energetic particle slowing down in Wendelstein 7-X
Authors: Lazerson Samuel A. , Pfefferlé David , Drevlak Michael , Smith Håkan , Geiger Joachim , Äkäslompolo Simppa , Xanthopoulos Pavlos , Dinklage Andreas , Ford Oliver , McNeely Paul , Rust Norbert , Bozhenkov Sergey , Hartmann Dirk , Rahbarnia Kian , Andreeva Tamara , Schilling Jonathan , Brandt Christian , Neuner Ulrich , Thomsen Henning , Wolf Robert C. , W7-X Team The
Published: June 2021

The energetic particle slowing down model in the BEAMS3D stellarator neutral beam code is compared to analytic models and experimental data from the Wendelstein 7-X experiment (W7-X). Recently, the first neutral beam experiments were performed in W7-X, providing validation of neutral beam deposition codes (Lazerson S.A. et al 2020 Nucl. Fusion
60 076020). This work builds upon that work, and follows the gyro-center orbits of the neutral-beam-generated fast ions to the plasma boundary. Slowing down times based on measurements of diamagnetic energy changes are compared to simulation data. A discharge solely heated by neutral beam injection is used to compare neoclassical heat flux estimates to neutral beam fueling, heating, and current drive. Experimental estimates of electron heat diffusivity suggest that electron turbulence is destabilized by density peaking in the discharge. Neutral beam current drive dominates over bootstrap current, resulting in a reversal of the toroidal current, as seen experimentally. Particle losses and heat flux through the equilibrium boundary are described. The effects of the magnetic configuration and plasma density on such parameters are also assessed. Benchmarking based on analytic estimates and other energetic particle codes is presented.
3D-aCortex: an ultra-compact energy-efficient neurocomputing platform based on commercial 3D-NAND flash memories
Authors: Bavandpour Mohammad , Sahay Shubham , Mahmoodi Mohammad Reza , Strukov Dmitri B
Published: June 2021

We first propose an ultra-compact energy-efficient time-domain vector-by-matrix multiplier (VMM) based on commercial 3D-NAND flash memory structure. The proposed 3D-VMM uses a novel resistive successive integrate and re-scaling (RSIR) scheme to eliminate the stringent requirement of a bulky load capacitor which otherwise dominates the area- and energy-landscape of the conventional time-domain VMMs. Our rigorous analysis, performed at the 55 nm technology node, shows that RSIR-3D-VMM achieves a record-breaking area efficiency of ∼0.02 μm2/Byte and the energy efficiency of ∼6 f J/Op for a 500 × 500 4-bit VMM, representing 5× and 1.3× improvements over the previously reported 3D-VMM approach. Moreover, unlike the previous approach, the proposed VMM can be efficiently tailored to work in a smaller current output range. Our second major contribution is the development of 3D-aCortex, a multi-purpose neuromorphic inference processor that utilizes the proposed 3D-VMM block as its core processing unit. Rigorous performance modeling of the 3D-aCortex targeting several state-of-the-art neural network benchmarks has shown that it may provide a record-breaking 30.7 MB mm−2 storage efficiency, 113.3 TOp/J peak energy efficiency, and 10.66 TOp/s computational throughput. The system-level analysis indicates that the gain in the area-efficiency of RSIR leads to a smaller data transfer delay, which compensates for the reduction in the VMM throughput due to an increased input time window.
Metabolomic analysis reveals reliance on secondary plant metabolites to facilitate carnivory in the Cape sundew,Drosera capensis
Authors: Hatcher Christopher R , Sommer Ulf , Heaney Liam M , Millett Jonathan
Published: June 2021

Background and Aims

Secondary metabolites are integral to multiple key plant processes (growth regulation, pollinator attraction and interactions with conspecifics, competitors and symbionts) yet their role in plant adaptation remains an underexplored area of research. Carnivorous plants use secondary metabolites to acquire nutrients from prey, but the extent of the role of secondary metabolites in plant carnivory is not known. We aimed to determine the extent of the role of secondary metabolites in facilitating carnivory of the Cape sundew, Drosera capensis.

Methods

We conducted metabolomic analysis of 72 plants in a time-series experiment before and after simulated prey capture. We used ultra-high-performance liquid chromatography–tandem mass spectrometry (UHPLC–MS/MS) and the retention time index to identify compounds in the leaf trap tissue that changed up to 72 h following simulated prey capture. We identified associated metabolic pathways, and cross-compared these compounds with metabolites previously known to be involved in carnivorous plants across taxa.

Key Results

For the first time in a carnivorous plant, we have profiled the whole-leaf metabolome response to prey capture. Reliance on secondary plant metabolites was higher than previously thought – 2383 out of 3257 compounds in fed leaves had statistically significant concentration changes in comparison with unfed controls. Of these, ~34 compounds are also associated with carnivory in other species; 11 are unique to Nepenthales. At least 20 compounds had 10-fold changes in concentration, 12 of which had 30-fold changes and are typically associated with defence or attraction in non-carnivorous plants.

Conclusions

Secondary plant metabolites are utilized in plant carnivory to an extent greater than previously thought – we found a whole-metabolome response to prey capture. Plant carnivory, at the metabolic level, likely evolved from at least two distinct functions: attraction and defence. Findings of this study support the hypothesis that secondary metabolites play an important role in plant diversification and adaptation to new environments.