bluuebunny/crossref_metadata_2025 huggingface dataset:
Continuous-wave planar laser induced fluorescence with a fast camera
Authors: Paul M. C. , Scime E. E.
Published: April 2021

We present planar, laser induced fluorescence (PLIF) measurements of the velocity-resolved distribution function of ions in a plasma using a modulated, narrow linewidth, continuous-wave laser. Plasma emission is acquired with a high frame rate camera, and the laser light is spread into a thin sheet so that an entire plane of the plasma is imaged at each interrogation wavelength. Fourier analysis is conducted on each pixel of the images to separate the modulated fluorescent emission from the background light. Argon ion temperatures and bulk flow maps are reported in a helicon plasma source, and standard single-point LIF measurements provide validation of the PLIF measurement.
An 18.3 MJ charging and discharging pulsed power supply system for the Space Plasma Environment Research Facility (SPERF): The subsystem for the dipole coil
Authors: E Peng , Guan Jian , Ma Xun , Mao Aohua , Deng Weijun , Ding Mingjun , Kang Chuanhui , Li Songjie , Xiao Jinshui , Li Hongtao
Published: April 2021

The Space Plasma Environment Research Facility (SPERF) currently under construction at the Harbin Institute of Technology in China is a user facility dedicated to studying space plasma physics on the ground. A coil system of the SPERF consists of seven types of coils, which are used to generate the magnetic fields and plasma required by the physical experiments. A dipole coil of the coil system works with four magnetosheath coils (flux cores) to build the magnetic fields resembling that of the Earth and solar wind. A capacitor-based pulsed power supply (PPS) system with a modular design is developed to excite the dipole coil to generate a magnetosphere-like magnetic field required by the magnetopause magnetic reconnection experiment. The PPS of the dipole coil has a longer pulse duration and more energy than that of other coils in the coil system, it delivers a pulsed current with a peak of more than 18 kA, and the duration of the current is not less than 95% of the peak over 10 ms to the dipole coil when the charging voltage is not less than 20 kV. The detailed design of the PPS is discussed in this paper, and the discharge test of the PPS is carried out to verify the design of the PPS.
Simultaneous ambient pressure x-ray photoelectron spectroscopy and grazing incidence x-ray scattering in gas environments
Authors: Kersell Heath , Chen Pengyuan , Martins Henrique , Lu Qiyang , Brausse Felix , Liu Bo-Hong , Blum Monika , Roy Sujoy , Rude Bruce , Kilcoyne Arthur , Bluhm Hendrik , Nemšák Slavomír
Published: April 2021

We have developed an experimental system to simultaneously measure surface structure, morphology, composition, chemical state, and chemical activity for samples in gas phase environments. This is accomplished by simultaneously measuring x-ray photoelectron spectroscopy (XPS) and grazing incidence x-ray scattering in gas pressures as high as the multi-Torr regime while also recording mass spectrometry. Scattering patterns reflect near-surface sample structures from the nano-scale to the meso-scale, and the grazing incidence geometry provides tunable depth sensitivity of structural measurements. Scattered x rays are detected across a broad range of angles using a newly designed pivoting-UHV-manipulator for detector positioning. At the same time, XPS and mass spectrometry can be measured, all from the same sample spot and under ambient conditions. To demonstrate the capabilities of this system, we measured the chemical state, composition, and structure of Ag-behenate on a Si(001) wafer in vacuum and in O2 atmosphere at various temperatures. These simultaneous structural, chemical, and gas phase product probes enable detailed insights into the interplay between the structure and chemical state for samples in gas phase environments. The compact size of our pivoting-UHV-manipulator makes it possible to retrofit this technique into existing spectroscopic instruments installed at synchrotron beamlines. Because many synchrotron facilities are planning or undergoing upgrades to diffraction limited storage rings with transversely coherent beams, a newly emerging set of coherent x-ray scattering experiments can greatly benefit from the concepts we present here.
Precision defect engineering of metal/insulator/metal diodes using atomic layer deposition to localize Ni impurities in Al2O3 tunnel barriers
Authors: Holden Konner E. K. , Qi Yitong , Conley John F.
Published: April 2021

Extrinsic impurity defect engineering is demonstrated to increase the maximum asymmetry of metal/insulator/metal (MIM) tunnel diodes. Using atomic layer deposition, transition metal Ni impurities are inserted at precise physical locations within the thickness of the insulating tunnel barrier in asymmetric electrode TiN/Al2O3/Al MIM diodes. The presence of Ni in Al2O3 is found to suppress the onset of Fowler–Nordheim tunneling from the Al electrode without changing the relative dielectric constant or refractive index of the insulator. Current–voltage asymmetry, a performance metric for MIM diodes, is reversed in Al2O3(Ni) devices and is increased over the control Al2O3 device (without Ni impurities) when the Ni impurities are placed close to the Al electrode. Capacitance–voltage measurements on MIM and metal/oxide/semiconductor devices along with Fowler–Nordheim derivative analysis all indicate the introduction of negative charge highly correlated with the position of the Ni defect layer within the Al2O3. Internal photoemission measurements show little change in zero-field energy barrier heights at the electrode interfaces, but varying field dependencies with respect to the position of the Ni defect layer. Combined results suggest that the level of the deep states introduced by the Ni atoms in Al2O3 is consistent with DFT predictions for the corundum Al2O3 system. Overall, this work demonstrates the possibility of improving MIM diode performance using precisely placed extrinsic defects.
The ON–OFF switching of thermal spin crossover by interstitial solvent exchange in a layered ReV–CN–FeII coordination framework
Authors: Charytanowicz Tomasz , Zakrzewski Jakub J. , Dziedzic-Kocurek Katarzyna , Chorazy Szymon , Sieklucka Barbara
Published: April 2021

We present an advanced material exhibiting a spin crossover (SCO) effect generated by the combined application of two external stimuli, temperature and chemical treatment related to the crystallization solvent exchange. The reported material is based on a bimetallic {[FeII(4-Brphpy)4]3[ReV(CN)8]2}⋅7MeOH [1, 4-Brphpy = 4-(4-bromophenyl)pyridine] coordination network built of cyanido-bridged layers and interstitial methanol molecules. A weakly bonded solvent can be exchanged into the water, which results in a hydrated phase, {[FeII(4-Brphpy)4]3[ReV(CN)8]2}⋅5H2O (1-hyd). The difference in solvent content between 1 and 1-hyd is sufficient to induce a remarkable change in spin transition properties. Despite the {N6} coordination environment around Fe(II), 1 reveals a stable high-spin state in the whole 2–300 K temperature range, which was assigned to the stiffening of the framework due to a series of non-covalent interactions involving solvent and 4-Brphpy ligands. Upon the exchange of solvent to water, the framework of 1-hyd becomes more flexible producing a thermally induced SCO effect, which occurs in two distinguishable steps in the broad 70–250 K range. The 1 to 1-hyd transformation can be reversed by immersion in the original solvent, thus, the chemical ON–OFF switching of a thermal SCO effect was achieved. This work shows that solvent exchange processes within bimetallic layered FeII–[ReV(CN)8]3– networks give an efficient route for reversible chemical modulation of thermally induced SCO properties.
Significant suppression of galvanomagnetic signal under dynamical spin injection in CoFeB/Pt bilayer
Authors: Obinata Sora , Ohnishi Kohei , Kimura Takashi
Published: April 2021

An effective detection structure for a dynamical spin injection in a ferromagnetic/nonmagnetic metal bilayer has been developed. We demonstrate a clear detection of a highly symmetric signal, indicating a significant suppression of spurious signals due to the galvanomagnetic effects from the ferromagnetic layer. The angular dependence of the signal amplitude assures that the observed signal is caused by the inverse spin Hall effect due to the dynamical spin injection. We also find the importance of the eddy current that induces spin-rectified signals from a ferromagnetic layer.
Multi-walled carbon nanotubes doping for fast and efficient hybrid solid state electrochromic device
Authors: Kandpal Suchita , Ghosh Tanushree , Sharma Meenu , Pathak Devesh K. , Tanwar Manushree , Rani Chanchal , Bhatia Ravi , Sameera I. , Chaudhary Anjali , Kumar Rajesh
Published: April 2021

Overall performance of a polythiophene-ethyl viologen-based solid state electrochromic device has been improved by doping with multi-walled carbon nanotubes (MWCNTs) to exploit its ballistic transport capabilities. The finished hybrid (organic–inorganic) device is free from liquid electrolyte and shows the most efficient color switching with a very small bias and high color contrast while switching between magenta and blue color states. The MWCNTs have been synthesized using the simple pyrolysis method and doped in the viologen containing layer after proper characterization using x-ray diffraction, electron microscopy, and Raman spectroscopy. In situ UV-Vis spectroscopy has been used to quantify the performance of the device that works on the mutual redox-based mechanism of viologen-polythiophene layers. In situ Raman microscopy and spectroscopy have been used to establish the working mechanism duly validated by electrical I-V characteristics of the device. The simple doping process makes the device the most efficient one in the family of polythiophene-based devices. Overall, a liquid electrolyte less, power efficient solid state electrochromic device with a switching time of 1s/0.5 s, a coloration efficiency of 401 cm2/C, a contrast ratio of 79%, and a stability of more than 100 cycles has been achieved.
Reaction mechanisms of H(D) → D(H) + Pt(111) interaction system: Quasiclassical molecular dynamics simulations
Authors: Vurdu Can Doğan
Published: April 2021

Reaction mechanisms of the H(or D) → D(or H) + Pt(111) interaction system have been proposed by using quasiclassical molecular dynamics simulations. First, the adsorbate atoms are dispersed randomly over the surface’s adsorption sites to form 0.18 ML, 0.25 ML, and 0.50 ML of coverages. Since the surface is considered to be resilient, thanks to imitating the multi-layer slab by using a function of many-body embedded-atom potential energy, the slab atoms can move because of the implemented external forces. Thus, energy transfer from the incident atom to surface atoms and adsorbates has been considered a real collision system. Moreover, the London–Eyring–Polanyi–Sato function is modified to model interaction between the adsorbates and slab atoms. In addition to desorption of HD and H2(or D2) after the collision of the incoming H(or D) atom with the surface, subsurface penetration, sticking on the surface, and inelastic reflection of the incident atom have been investigated in detail as the reaction mechanisms on the surface. In addition, isotopic effects on reaction mechanisms have been analyzed in depth and shown. Also, hot-atom and Eley–Rideal mechanisms have been examined and explained. The hot-atom mechanism is responsible for the formation of H2/D2 products. Furthermore, the sticking rate on the surface is lower than the rate of subsurface penetration.
Phase transitions on a class of generalized Vicsek-like models of collective motion
Authors: Clusella Pau , Pastor-Satorras Romualdo
Published: April 2021

Systems composed of interacting self-propelled particles (SPPs) display different forms of order–disorder phase transitions relevant to collective motion. In this paper, we propose a generalization of the Vicsek model characterized by an angular noise term following an arbitrary probability density function, which might depend on the state of the system and thus have a multiplicative character. We show that the well established vectorial Vicsek model can be expressed in this general formalism by deriving the corresponding angular probability density function, as well as we propose two new multiplicative models consisting of bivariate Gaussian and wrapped Gaussian distributions. With the proposed formalism, the mean-field system can be solved using the mean resultant length of the angular stochastic term. Accordingly, when the SPPs interact globally, the character of the phase transition depends on the choice of the noise distribution, being first order with a hybrid scaling for the vectorial and wrapped Gaussian distributions, and second order for the bivariate Gaussian distribution. Numerical simulations reveal that this scenario also holds when the interactions among SPPs are given by a static complex network. On the other hand, using spatial short-range interactions displays, in all the considered instances, a discontinuous transition with a coexistence region, consistent with the original formulation of the Vicsek model.
Light-matter interaction in open cavities with dielectric stacks
Authors: Saharyan Astghik , Álvarez Juan-Rafael , Doherty Thomas H. , Kuhn Axel , Guérin Stéphane
Published: April 2021

We evaluate the exact dipole coupling strength between a single emitter and the radiation field within an optical cavity, taking into account the effects of multilayer dielectric mirrors. Our model allows one to freely vary the resonance frequency of the cavity, the frequency of light or atomic transition addressing it, and the design wavelength of the dielectric mirror. The coupling strength is derived for an open system with unbound frequency modes. For very short cavities, the effective length used to determine their mode volume and the lengths defining their resonances are different, and also found to diverge appreciably from their geometric length, with the radiation field being strongest within the dielectric mirror itself. Only for cavities much longer than their resonant wavelength does the mode volume asymptotically approach that normally assumed from their geometric length.
Surface roughness effect on the shear thinning of non-colloidal suspensions
Authors: Lin Yuan , Wang Ying , Qin Huaitao , Pan Dingyi , Chen Jiawang
Published: April 2021

The shear thinning behavior of non-colloidal suspensions is investigated experimentally with emphasis on the effect of surface roughness of suspending particles. The first shear thinning at a low shear-rate is observed, which originates from particle–particle interaction, and the second shear thinning at a high shear rate is also reported as the polymeric solvent shear thins. Due to the decrease of the size of particle clusters, the viscosity of suspensions decreases in the first shear thinning regime. The surface asperities on rough particles hinders the lubricative interaction between close-contact particles suppressing the growth of clusters, and therefore, the first shear thinning behavior weakens. The shielding of the lubricative interaction also prevents the local shear rate enhancement, corresponding to the suppressions second shear thinning and the rising of a second-order first normal stress difference from the polymeric solvent. A theoretical model describing the first shear thinning behavior of non-colloidal suspension is developed, and the predications agree well with experimental data. The roughness effect on dynamic rheological behavior is also investigated.
Impact factor analysis on precision of magnetic gradient full tensor measurement system
Authors: Xu Lei , Zhang Ning , Chen Huadong , Lin Chunsheng , Li Xu , Huo Ruikun
Published: April 2021

In order to achieve a comprehensive analysis of the influencing factors on the accuracy of the magnetic gradient full tensor measurement system, an orthogonal experimental design method is proposed to analyze the errors caused by the influencing factors. The influence of each factor on the accuracy of the measurement system is obtained more comprehensively. Furthermore, the relative degree of influence of the factor is obtained. Four factors including resolution, baseline length, measurement distance, and magnetic moment direction are selected for simulation calculation. The simulation results and analysis show that among the selected factors, the resolution has the greatest influence on the accuracy of the measurement system and the magnetic moment direction has the least influence. In the actual measurement system design, if the optimal configuration of the four factors cannot be satisfied, the former can be satisfied in priority in the order of resolution, measurement distance, baseline length, and magnetic moment direction.
Controlling potential difference between electrodes based on self-consistent-charge density functional tight binding
Authors: Oshiki Jun , Nakano Hiroshi , Sato Hirofumi
Published: April 2021

A proper understanding and description of the electronic response of the electrode surfaces in electrochemical systems are quite important because the interactions between the electrode surface and electrolyte give rise to unique and useful interfacial properties. Atomistic modeling of the electrodes requires not only an accurate description of the electronic response under a constant-potential condition but also computational efficiency in order to deal with systems large enough to investigate the interfacial electrolyte structures. We thus develop a self-consistent-charge density functional tight binding based method to model a pair of electrodes in electrochemical cells under the constant-potential condition. The method is more efficient than the (ab initio) density functional theory calculations so that it can treat systems as large as those studied in classical atomistic simulations. It can also describe the electronic response of electrodes quantum mechanically and more accurately than the classical counterparts. The constant-potential condition is introduced through a Legendre transformation of the electronic energy with respect to the difference in the number of electrons in the two electrodes and their electrochemical potential difference, through which the Kohn–Sham equations for each electrode are variationally derived. The method is applied to platinum electrodes faced parallel to each other under an applied voltage. The electronic response to the voltage and a charged particle is compared with the result of a classical constant-potential method based on the chemical potential equalization principle.
Role of pulsatility on particle dispersion in expiratory
flows
Authors: Monroe K. , Yao Y. , Lattanzi A. , Raghav V. , Capecelatro J.
Published: April 2021

Expiratory events, such as coughs, are often pulsatile in nature and result in vortical flow structures that transport respiratory particles. In this work, direct numerical simulation (DNS) of turbulent pulsatile jets, coupled with Lagrangian particle tracking of micron-sized droplets, is performed to investigate the role of secondary and tertiary expulsions on particle dispersion and penetration. Fully developed turbulence obtained from DNS of a turbulent pipe flow is provided at the jet orifice. The volumetric flow rate at the orifice is modulated in time according to a damped sine wave, thereby allowing for control of the number of pulses, duration, and peak amplitude. Thermodynamic effects, such as evaporation and buoyancy, are neglected in order to isolate the role of pulsatility on particle dispersion. The resulting vortex structures are analyzed for single-, two-, and three-pulse jets. The evolution of the particle cloud is then compared to existing single-pulse models. Particle dispersion and penetration of the entire cloud are found to be hindered by increased pulsatility. However, the penetration of particles emanating from a secondary or tertiary expulsion is enhanced due to acceleration downstream by vortex structures.
Enhanced ductility and optoelectronic properties of environment-friendly CsGeCl3 under pressure
Authors: Islam M. A. , Islam Jakiul , Islam M. Nazrul , Sen Sapan Kumar , Hossain A. K. M. Akther
Published: April 2021

Eco-friendly inorganic halide perovskite materials with numerous structural configurations and compositions are now in the leading place of researcher’s attention for outstanding photovoltaic and optoelectronic performance. In the present approach, density functional theory calculations have been performed to explore the structural, mechanical, electronic, and optical properties of perovskite-type CsGeCl3 under various hydrostatic pressures, up to 10 GPa. The result shows that the optical absorption and conductivity are directed toward the low-energy region (red shift) remarkably with increasing pressure. The analysis of mechanical properties certifies that CsGeCl3 has ductile entity and the ductile manner has increasing affinity with applied pressure. The decreasing affinity of the bandgap is also perceived with applied pressure, which notifies that the performance of the optoelectronic device can be tuned and developed under pressure.
Role of testing for the COVID-19 response in Aboriginal, Torres Strait Islander and regional populations
Authors: Speers David
Published: April 2021

Aboriginal and Torres Strait Islander people may be disproportionately affected by COVID-19 and despite isolation remote communities have an increased risk of COVID-19 transmission due to overcrowding and frequent travel over long distances for family, cultural or community events. The response to an outbreak in remote settings will be logistically challenging requiring a coordinated multiagency response. The provision of timely COVID-19 diagnostic testing is central to this response.
Vaccination for COVID-19 control and considerations for Australia
Authors: MacIntyre Raina
Published: April 2021

Vaccines remain the main prospect for an exit strategy from the COVID-19 pandemic, and may, depending on efficacy, duration of protection and uptake, make herd immunity feasible. If herd immunity is not achievable, SARS-COV-2 will circulate long-term. There are many vaccine candidates in development and choices between vaccines that will vary in efficacy and safety. The efficacy of available vaccines is compared and ranges from 62–95% against symptomatic infection with the G614 variant. Efficacy is reduced against new variants of concern and is uncertain against asymptomatic infection. Some vaccines show a better protective immune response than natural infection. The principles of herd immunity and prerequisites for achieving it, such as vaccine efficacy, duration of protection and coverage, are discussed. The alternative vaccine strategies including mass vaccination, targeted risk or age-based vaccination and ring vaccination, as well as speed of vaccination are reviewed. Finally, the impact of variants of concern on vaccine programs and the logistics of mass vaccination are discussed.
Longitudinal trends of future suitable climate for conserving oil palm indicates refuges in tropical south-east Asia with comparisons to Africa and South America
Authors: Paterson R. Russell M.
Published: April 2021

Palms are crucial species to the flora of south-east (SE) Asia. Oil palm (OP) is a highly significant introduced species to the region and produces palm oil, an especially important commodity. OPs are grown in huge plantations in SE Asia, predominantly in Malaysia and Indonesia. These palms have detrimental effects on the environment, particularly from deforestation when creating new plantations. Future climate scenarios have indicated mostly reductions in suitable climate for growing OP throughout SE Asia and it is crucial to consider how the palms can be conserved. Climate change has been shown to stimulate poleward movements in some other species, which assist in conserving them and may permit assisted colonisation. However, poleward movement to these refuges is unlikely from the tropics. Recent research has indicated potential longitudinal refuges for OP in Africa and phased longitudinal refuges in South America, based on future suitable climate (SC) for growing OP. These data indicate how the sustainability of OP could be maintained rather than experiencing the complete decimation of the crop, which might otherwise occur. This current work was undertaken to determine trends of future SC for growing OP in SE Asia and to indicate refuges with implications for conservation and plantation management. The results are compared with those for Africa and South America. The longitudes considered in SE Asia were from 100°E to 146°E, which is an intentionally large area of land. The maps obtained from the climate modelling program CLIMEX, of climate suitability for growing OP, were employed to obtain the percentage SC in SE Asian regions and countries for current time (CT), 2050 and 2100. The average percentage SC decreased for 2050 and further for 2100. Increasing longitudinal trends in SC for growing OP were observed from CT to 2050, CT to 2100 and 2050 to 2100 from west to east. Vietnam, the Philippines, Papua New Guinea (PNG) and island Malaysia had increased SC by 2050. Large decreases in SC by 2050 for Thailand, Laos and Cambodia, which are towards the west of SE Asia, were observed. There was an increasing trend in suitable climate from CT to 2100 and a smaller trend from 2050 to 2100. Hence, OP may find suitable refuges by natural seed spreading towards the east of SE Asia, hence avoiding extinction. Similarly, new plantations could be established in the same direction, although environmental concerns are paramount. Vietnam, the Philippines, PNG and island Malaysia may become more suitable than Thailand, Laos and Cambodia. The sustainability of OP plantations is likely to decrease substantially with climate change. However, there is scope for a more sustainable situation towards the east of SE Asia. New plantations cannot be established without considering the severe effects on the environment from deforestation and increased greenhouse gases. Overall, urgent action is required to reduce the effects of climate change.
PI3Kγ inhibition suppresses microglia/TAM accumulation in glioblastoma microenvironment to promote exceptional temozolomide response
Authors: Li Jie , Kaneda Megan M. , Ma Jun , Li Ming , Shepard Ryan M. , Patel Kunal , Koga Tomoyuki , Sarver Aaron , Furnari Frank , Xu Beibei , Dhawan Sanjay , Ning Jianfang , Zhu Hua , Wu Anhua , You Gan , Jiang Tao , Venteicher Andrew S. , Rich Jeremy N. , Glass Christopher K. , Varner Judith A. , Chen Clark C.
Published: April 2021

Significance

Understanding the basis for exceptional responders represents a key pillar in the framework of precision medicine. In this study, we utilized distinct informatics platforms to analyze the expression profiles of clinically annotated tumor specimens derived from patients afflicted with glioblastoma, the most common form of primary brain cancer. These analyses converged on prognostic contributions from glioblastoma-associated microglia/macrophages. Glioblastoma-associated microglia-secreted interleukin 11 (IL11) to activate a STAT3-MYC signaling axis in glioblastoma cells, facilitating resistance to the standard-of-care chemotherapy, temozolomide. Microglia recruitment and IL11 secretion were dependent on the myeloid-specific phosphoinositide-3-kinase gamma isoform (PI3Kγ). Inhibition or genetic inactivation of PI3Kγ in murine glioblastoma models recapitulated expression profiles observed in specimens derived from exceptional responders, suggesting a potential for clinical translation.
Signatures of two-dimensional superconductivity emerging within a three-dimensional host superconductor
Authors: Parra Carolina , Niestemski Francis C. , Contryman Alex W. , Giraldo-Gallo Paula , Geballe Theodore H. , Fisher Ian R. , Manoharan Hari C.
Published: April 2021

Significance

We report signatures of a new phenomenon wherein a hidden “interdimensional” order emerges from a bulk three-dimensional superconductor tuned to approach a phase transition to an insulator. Prior electrical transport measurements found that the superconductor–insulator transition of BaPb

1−
x

Bi

x

O
3
demonstrated critical scaling behavior but inexplicably required parameters consistent only with two dimensions. Here, we directly image the three-dimensional superconducting state as it approaches an insulating phase and discover that signatures of a two-dimensional granular superconducting phase spontaneously emerge at the transition. Moreover, the properties of this phase precisely match the theory of emergent electronic granularity specific to two-dimensional materials. These findings posit that a three-dimensional superconductor electronically reorganizes itself into a two-dimensional granular superconductor before ultimately transforming to an insulator.
Early, intensive marine resource exploitation by Middle Stone Age humans at Ysterfontein 1 rockshelter, South Africa
Authors: Niespolo Elizabeth M. , Sharp Warren D. , Avery Graham , Dawson Todd E.
Published: April 2021

Significance

Novel
230
Th/U burial dating of ostrich eggshells complements other dating methods applicable to archaeological materials beyond the range of radiocarbon dating. New ages for the Ysterfontein 1 (YFT1) shell midden show it accumulated rapidly between ∼120 to 113 ka closely following the Last Interglacial sea-level highstand. The ages show the great antiquity of intensive human coastal adaptation, date a distinctive lithic industry, and show that teeth from YFT1 are among the oldest
H. sapiens
fossils recovered in southern Africa. Stable isotopes of ostrich eggshells indicate rapid cooling and drying during site occupation. Despite rapid sea-level drop and increasing aridity, the site’s occupants maintained a consistent diet, which may not indicate a stable paleoenvironment but rather results from systematic, selective foraging.
A moisture-enabled fully printable power source inspired by electric eels
Authors: Yang Lu , Yang Feiyao , Liu Xu , Li Ke , Zhou Yaning , Wang Yangjian , Yu Tianhao , Zhong Mengjuan , Xu Xiaobing , Zhang Lijuan , Shen Wei , Wei Di
Published: April 2021

Significance

Future wearable and printable electronics call for scalable production of power sources that can provide green electric energy. The chemical potential energy of the ion gradient is ubiquitous in nature and is the foundation of many living species. Herein, inspired by electric eels, a new power source printed from graphene inks can convert the chemical potential energy of the ion gradient to electric output in the presence of moisture. An ultrahigh voltage of 192 V is achieved on a strip of paper substrate. Two- and three-dimensional cell structures are designed by adapting the mathematical fractal curves and a origami-folding strategy. The industrial-scale production of graphene materials coupled with the reproducibility of printing technology could open new scenarios of cost-effective graphene electronic devices.
The cumulative risk of jail incarceration
Authors: Western Bruce , Davis Jaclyn , Ganter Flavien , Smith Natalie
Published: April 2021

Significance

Research on incarceration has focused on prisons, but the scale of admissions to local jails is significantly higher. The average length of stay in jail is brief compared to imprisonment, but jail incarceration has been found to adversely affect court outcomes, earnings, and family life. Although New York has one of the lowest jail incarceration rates among large cities, over a quarter of Black men and a sixth of Latino men in the city have been jailed by age 38 y. Risks of jail incarceration are 40 to 50% higher in poor neighborhoods.
CCRL2 promotes antitumor T-cell immunity via amplifying TLR4-mediated immunostimulatory macrophage activation
Authors: Yin Wei , Li Yihong , Song Yan , Zhang Jiarui , Wu Chao , Chen Yu , Miao Ying , Lin Changdong , Lin Yuli , Yan Dapeng , Chen Jianfeng , He Rui
Published: April 2021

Significance

Macrophages play a key role in shaping tumor immunity. CCRL2 was originally cloned from LPS-stimulated macrophages; however, whether CCRL2 influences tumor immunity by regulating macrophage function remains unknown. In this study, we identify CCRL2 as a predictive indicator of robust antitumor immunity in human cancers and report the predominant expression of CCLR2 in TAM with immunostimulatory phenotypes. We also reveal the functional role of CCRL2 in potentiating antitumor immunity. Specifically, CCRL2 that is primarily induced by TLR4 agonists in turn interacts with TLR4 to facilitate its retainment in cell surface, thereby amplifying membrane TLR4-mediated downstream inflammatory signaling, finally leading to optimal activation of immunostimulatory macrophages and subsequent antitumor CD8+T-cell responses.
Excess mortality in the United States in the 21st century
Authors: Preston Samuel H. , Vierboom Yana C.
Published: April 2021

We use three indexes to identify how age-specific mortality rates in the United States compare to those in a composite of five large European countries since 2000. First, we examine the ratio of age-specific death rates in the United States to those in Europe. These show a sharp deterioration in the US position since 2000. Applying European age-specific death rates in 2017 to the US population, we then show that adverse mortality conditions in the United States resulted in 400,700 excess deaths that year. Finally, we show that these excess deaths entailed a loss of 13.0 My of life. In 2017, excess deaths and years of life lost in the United States represent a larger annual loss of life than that associated with the COVID-19 epidemic in 2020.
A new strategy to toughen NbCr2 Laves phase
Authors: Li Kewei , Liu Jianyu , Wang Yongzhe , Gao Fei
Published: April 2021

A new strategy to toughen NbCr2 Laves phase was proposed, in which ductile Cr and Nb solid solutions were incorporated by accelerating solute segregation within NbCr2 matrix using external applied pulsed electric current. A dense bulk consisting of ultrafine NbCr2 grains with abundant Cr and Nb solid solutions along the grain boundaries was produced by spark plasma sintering using monolithic NbCr2 starting powders. The formation of Cr and Nb solid solutions was attributed to the enhanced atomic transport, which facilitated the mobility of dislocations and the selective Joule heating. The fracture toughness of the sample achieved 11.3 MPa·m1/2, which was 9.4 times the as-cast NbCr2 (1.2 MPa·m1/2) and thus can be regarded as a new toughening mechanism.
The Less Eligible Eaters: Calorie Counts, No-Frills, and Vending Machines in Prison
Authors: Labotka Lori
Published: April 2021

The Least Eligibility Principle (LEP) has been variously engaged throughout US history to sort service populations into the deserving and undeserving. The no-frills prison policy movement of the 1990s was heavily influenced by LEP morality. Food was one focal point of the discourses and policies that negotiated the floating signifier “least” to place prisoners at the bottom of the presumed hierarchy, encouraging a punitive penal diet. Based on ethnographic data collected from a US prison for women, I explore women’s practices that negotiate their relationship to this diet. Following Abu-Lughod’s (1990) suggestion, I consider these daily acts of resistance to reveal the workings of power. The hollowed-out diet disciplines as it presupposes the moral classification of LEP, indexing the unworthiness of those who must consume it. The impacts of the disciplinary diet are far-reaching, encouraging the accumulation of debt while incarcerated and placing unyielding financial pressure on incarcerated individuals’ kin networks. State and civil society are continuous in the ideological negotiation that supports the punitive penal diet. Women’s practices that challenge the moral implications of this diet claim humanity and dignity in a system that presupposes their unworthiness and positions them as morally bankrupt.
Supersolid behavior in one-dimensional self-trapped Bose–Einstein condensate
Authors: Parit Mithilesh K , Tyagi Gargi , Singh Dheerendra , Panigrahi Prasanta K
Published: April 2021

Supersolid is an exotic state of matter, showing crystalline order with a superfluid background, observed recently in dipolar Bose–Einstein condensate in a trap. Here, we present exact Bloch wave function of the self-trapped supersolid phase, in the presence of mean-field and beyond mean-field interaction. Our general solutions of the amended nonlinear Schrödinger equation are obtained through Möbius transform, connecting a wide class of supersolid solutions to the ubiquitous cnoidal waves. The solutions yield the supersolid phase in the self-trapped quantum matter, where an array of quantum droplets exist, accompanied by a constant condensate. For the supersolid phase, the chemical potential for one class of solutions is the same as that of self-trapped quantum droplets, and is lower for the general non-perturbative solution. Due to the destabilizing effects of fluctuations on long range order in one dimension, the realization of the supersolid phase may be possible in a finite system.
Modeling nanoparticle charge distribution in the afterglow of non-thermal plasmas and comparison with measurements
Authors: Suresh Vikram , Li Li , Redmond Go Felipe Joshua , Gopalakrishnan Ranganathan
Published: April 2021

Particle charging in the afterglows of non-thermal plasmas typically take place in a non-neutral space charge environment. We model the same by incorporating particle–ion collision rate constant models, developed in prior work by analyzing particle–ion trajectories calculated using Langevin Dynamics (LD) simulations, into species transport equations for ions, electrons and charged particles in the afterglow. A scaling analysis of particle charging and additional LD calculations of the particle–ion collision rate constant are presented to extend the range of applicability to ion electrostatic to thermal energy ratios of 300 and diffusive Knudsen number (that scales inversely with gas pressure) up to 2000. The developed collision rate constant models are first validated by comparing predictions of particle charge against measured values in a stationary, non-thermal DC plasma from past PK-4 campaigns published in Ratynskaia et al (2004 Phys. Rev. Lett. 93 085001) and Khrapak et al (2005 Phys. Rev. E 72 016406). The comparisons reveal excellent agreement within

±
35
%

for particles of radius

0.6
,
1.0
,
1.3
 
μ

m

in the gas pressure range of

∼
20
−
150
Pa

. The experiments to probe particle charge distributions by Sharma et al (2020 J. Physics D: Appl. Phys. 53 245204) are modeled using the validated particle–ion collision rate constant models and the calculated charge fractions are compared with measurements. The comparisons reveal that the ion/electron concentration and gas temperature in the afterglow critically influence the particle charge and the predictions are generally in qualitative agreement with the measurements. Along with critical assessment of the modeling assumptions, several recommendations are presented for future experimental design to probe charging in afterglows.
Ultra-coarse-graining of homopolymers in inhomogeneous systems
Authors: Berressem Fabian , Scherer Christoph , Andrienko Denis , Nikoubashman Arash
Published: April 2021

We develop coarse-grained (CG) models for simulating homopolymers in inhomogeneous systems, focusing on polymer films and droplets. If the CG polymers interact solely through two-body potentials, then the films and droplets either dissolve or collapse into small aggregates, depending on whether the effective polymer–polymer interactions have been determined from reference simulations in the bulk or at infinite dilution. To address this shortcoming, we include higher order interactions either through an additional three-body potential or a local density-dependent potential (LDP). We parameterize the two- and three-body potentials via force matching, and the LDP through relative entropy minimization. While the CG models with three-body interactions fail at reproducing stable polymer films and droplets, CG simulations with an LDP are able to do so. Minor quantitative differences between the reference and the CG simulations, namely a slight broadening of interfaces accompanied by a smaller surface tension in the CG simulations, can be attributed to the deformation of polymers near the interfaces, which cannot be resolved in the CG representation, where the polymers are mapped to spherical beads.
Role of pH in the synthesis and growth of gold nanoparticles using L-asparagine: a combined experimental and simulation study
Authors: Báez-Cruz Ricardo , Baptista Luis A , Ntim Samuel , Manidurai Paulraj , Espinoza Shirly , Ramanan Charusheela , Cortes-Huerto Robinson , Sulpizi Marialore
Published: April 2021

The use of biomolecules as capping and reducing agents in the synthesis of metallic nanoparticles constitutes a promising framework to achieve desired functional properties with minimal toxicity. The system’s complexity and the large number of variables involved represent a challenge for theoretical and experimental investigations aiming at devising precise synthesis protocols. In this work, we use L-asparagine (Asn), an amino acid building block of large biomolecular systems, to synthesise gold nanoparticles (AuNPs) in aqueous solution at controlled pH. The use of Asn offers a primary system that allows us to understand the role of biomolecules in synthesising metallic nanoparticles. Our results indicate that AuNPs synthesised in acidic (pH 6) and basic (pH 9) environments exhibit somewhat different morphologies. We investigate these AuNPs via Raman scattering experiments and classical molecular dynamics simulations of zwitterionic and anionic Asn states adsorbing on (111)-, (100)-, (110)-, and (311)-oriented gold surfaces. A combined analysis suggests that the underlying mechanism controlling AuNPs geometry correlates with amine’s preferential adsorption over ammonium groups, enhanced upon increasing pH. Our simulations reveal that Asn (both zwitterionic and anionic) adsorption on gold (111) is essentially different from adsorption on more open surfaces. Water molecules strongly interact with the gold face-centred-cubic lattice and create traps, on the more open surfaces, that prevent the Asn from diffusing. These results indicate that pH is a relevant parameter in green-synthesis protocols with the capability to control the nanoparticle’s geometry, and pave the way to computational studies exploring the effect of water monolayers on the adsorption of small molecules on wet gold surfaces.
Traceability of optical 3D scanner measurements on sand mould in the production of quality castings
Authors: Yazdanbakhsh Seyed Alireza , Mohaghegh Kamran , Tiedje Niels Skat , Chiffre Leonardo De
Published: April 2021

This paper addresses the establishment of traceability of optical 3D scanner measurements on green sand mould in the production of quality castings. Optical measurements are subject to the influence of the workpiece material optical properties, which can be very different from those of conventional calibration artefacts, e.g. check boards, ball plates, etc. This means that an optical 3D scanner calibrated using a check board or a ball plate may give biased and unreliable results when used for dimensional measurements on a crystalline material such as sand. In order to use a tactile coordinate measuring machine as reference for optical measurements on a green sand mould, which cannot be probed directly, a hard furan sand cone plate was developed and substituted as reference workpiece for tactile as well as optical measurements. Systematic errors and measurement uncertainties were assessed for the optical measurements, and a maximum expanded uncertainty of 26 µm was estimated, which is acceptable for optical measurements on sand surfaces having single grains with an average diameter of 232 µm.
High-precision wavefront reconstruction from Shack-Hartmann wavefront sensor data by a deep convolutional neural network
Authors: Gu Hu , Zhao Ziyun , Zhang Zhigao , Cao Shuo , Wu Jingjing , Hu Lifa
Published: April 2021

The Shack–Hartmann wavefront sensor (SHWFS) has been widely used for measuring aberrations in adaptive optics systems. However, its traditional wavefront reconstruction method usually has limited precision under field conditions because the weight-of-center calculation is affected by many factors, such as low signal-to-noise-ratio objects, strong turbulence, and so on. In this paper, we present a ResNet50+ network that reconstructs the wavefront with high precision from the spot pattern of the SHWFS. In this method, a nonlinear relationship is built between the spot pattern and the corresponding Zernike coefficients without using a traditional weight-of-center calculation. The results indicate that the root-mean-square (RMS) value of the residual wavefront is 0.0128 μm, which is 0.79% of the original wavefront RMS. Additionally, we can reconstruct the wavefront under atmospheric conditions, if the ratio between the telescope aperture’s diameter D and the coherent length r
0 is 20 or if a natural guide star of the ninth magnitude is available, with an RMS reconstruction error of less than 0.1 μm. The method presented is effective in the measurement of wavefronts disturbed by atmospheric turbulence for the observation of weak astronomical objects.
In vitro anti-oxidant and cytotoxic activities of gold nanoparticles synthesized from an aqueous extract of the Xylopia aethiopica fruit
Authors: Anadozie Scholastica O , Adewale Olusola B , Meyer Mervin , Davids Hajierah , Roux Saartjie
Published: April 2021

The development of gold nanoparticles (AuNPs) using a green approach has drawn considerable interest in the field of nanomedicine. Its wide application in clinical diagnosis, imaging and therapeutics portrays its importance for human existence. In this study, we reported on the biogenic synthesis of AuNPs using the aqueous extract of the Xylopia aethiopica fruit (AEXAf), which acts as both a reducing and stabilizing agent. The characterization of AEXAf-AuNPs was performed using ultraviolet-visible spectroscopy, dynamic light scattering and zeta potential measurements, high-resolution transmission electron microscopy and Fourier transform-infrared spectroscopy. The i
n vitro anti-oxidant activities of the AEXAf-AuNPs and AEXAf were evaluated using 2,2-diphenyl-1-picrylhydrazyl (DPPH) and ferric reducing anti-oxidant power. The in vitro cytotoxic activities of the AEXAf-AuNPs and AEXAf against breast and colorectal cancer cells were evaluated using 3,-(4,5 dimethylthiazol)-2,5 diphenyl tetrazolium bromide (MTT) viability and annexin V/PI assays. The AEXAf-AuNPs exhibited surface plasmon absorption maximum at 522 nm and were stable for 4 weeks. The average size of the AEXAf-AuNPs was 10.61 ± 3.33 nm on the high-resolution transmission electron microscopy images. The in vitro anti-oxidant activities of the AEXAf-AuNPs and AEXAf were concentration dependent. The AEXAf-AuNPs were cytotoxic to the cancer cells and non-toxic to the non-cancerous human fibroblast cells (KMST-6) (up to 200 μg ml−1). From these results, the AEXAf-AuNPs showed good anti-oxidant and anti-cancer activities, and can be suggested as a possible therapeutic agent for breast and colorectal cancer.