bluuebunny/crossref_metadata_2025 huggingface dataset:
Novel design of a circulation control airfoil with cylinder rotation
Authors: Zhang Yang , Zhao Yunlong
Published: August 2023

The objective of this research is to investigate the efficacy of Magnus effect on a circulation control airfoil (CCA). To achieve this, the Reynolds-averaged Navier–Stokes method is employed to numerically simulate the flow around a three-dimensional CCA configuration. The numerical verification demonstrates that the k–ω shear stress transport turbulence model provides better characterization of flow circulation and separation in the trailing edge area of the airfoil while ensuring the independence of the grid. The rotation speed is set at 15%, 30%, and 45% of the free-stream velocity, respectively, encompassing both clockwise and counterclockwise directions. The analysis focused on the characteristics of lift-drag forces, velocity circulation, and flow separation. The findings reveal that as the rotational speed increases in a clockwise direction, there is a progressive enhancement in aerodynamic performance of the airfoil. Both the flow separation point and stagnation point exhibit a backward shift in their respective positions. However, counterclockwise rotation produces an opposing effect. The amplitudes of fluctuating aerodynamic force coefficients are suppressed completely whether in clockwise or in counterclockwise rotation, resulting in a stable flow pattern consisting of a pair of vortices near the trailing-edge area. While the qualitative application of Bernoulli's principle explains the correlation between velocity circulation and surface pressure, there is a 12% margin of error in the quantitative analysis. Furthermore, evaluating the efficiency of circulation control while taking into account the input energy reveals that rotating the cylinder at 45% of free-stream velocity leads to a 23.6% increase in the lift-to-drag ratio.
Origin of medium-range atomic correlation in simple liquids: Density wave theory
Authors: Egami Takeshi , Ryu Chae Woo
Published: August 2023

The atomic pair-distribution function of simple liquid and glass shows exponentially decaying oscillations beyond the first peak, representing the medium-range order (MRO). The structural coherence length that characterizes the exponential decay increases with decreasing temperature and freezes at the glass transition. Conventionally, the structure of liquid and glass is elucidated by focusing on a center atom and its neighboring atom shell characterized by the short-range order (SRO) and describing the global structure in terms of overlapping local clusters of atoms as building units. However, this local bottom-up approach fails to explain the strong drive to form the MRO, which is different in nature from the SRO. We propose to add an alternative top-down approach based upon the density wave theory. In this approach, one starts with a high-density gas state and seeks to minimize the global potential energy in reciprocal space through density waves using the pseudopotential. The local bottom-up and global top-down driving forces are not mutually compatible, and the competition and compromise between them result in a final structure with the MRO. This even-handed approach provides a more intuitive explanation of the structure of simple liquid and glass.
Identification of two-neuron FitzHugh–Nagumo model based on the speed-gradient and filtering
Authors: Rybalko A. , Fradkov A.
Published: August 2023

The paper is devoted to the parameter identification problem for two-neuron FitzHugh–Nagumo models under condition when only one variable, namely, the membrane potential, is measured. Another practical assumption is that both variable derivatives cannot be measured. Finally, it is assumed that the sensor measuring the membrane potential is imprecise, and all measurements have some unknown scaling factor. These circumstances bring additional difficulties to the parameters’ estimation problem, and therefore, such case was not studied before. To solve the problem first, the model is transformed to a more simple form without unmeasurable variables. Variables obtained from applying a second-order real filter-differentiator are used instead of unmeasurable derivatives. Then, an adaptive system, parameters of which are estimates of original system parameters, is designed. The estimation (identification) goal is to properly adjust parameter estimates. To this end, the speed-gradient method is employed. The correctness of the obtained solution is proved theoretically and illustrated by computer simulation in the Simulink environment. The sufficient conditions of asymptotically correct identification for the speed-gradient method with integral objective function are formulated and proved. The novelty of the paper is that in contrast to existing solutions to the FitzHugh–Nagumo identification problem, we take into account a systematic error of the membrane potential measurement. Furthermore, the parameters are estimated for a system composed of two FitzHugh–Nagumo models, which open perspectives for using the proposed results for modeling and estimation of parameters for neuron population.
Mode decomposition and simulation of cloud cavity behaviors around a composite hydrofoil
Authors: Liu Yunqing , Zhu Yichen , Huang Biao , Wu Qin
Published: August 2023

Numerical investigation of the cavity dynamics around a composite hydrofoil with a blunt trailing edge in the cloud cavitating flow is carried out using a tightly coupled fluid–structure interaction method. The hydrofoil is made of a carbon-fiber-reinforced polymers with a ply angle of −45∘(CFRP −45). The results of a stainless-steel hydrofoil with the same geometry and conditions are used as a reference. Simulation results have been validated carefully against experimental data. Several fundamental mechanisms are dictated through simulation results and mode decomposition, including the multistage shedding process, the influence of the bend–twist coupling effect on cavity behaviors, cavitation–vortex interaction, and kinematics of coherent structures. The main reason for the generation of a secondary re-entrant jet is that the primary cloud cavity collapse leads to high pressure, which spreads to the residual sheet cavity closure and then induces a high-pressure gradient. The negative bend–twist coupling effect causes the CFRP −45 hydrofoil to exhibit a smaller cloud cavity scale and non-uniform re-entrant jet strength in the spanwise direction compared to the stainless-steel hydrofoil. Modal decomposition via proper orthogonal decomposition and dynamic mode decomposition indicates that the dominant coherent structures in the cloud cavitating flow include the large-scale cloud cavity, rotating structures due to the re-entrant jet, attached cavity, and small-scale vortex in the wake. The results obtained in this study provide physical insight into the understanding of the mechanisms relevant to complex cloud cavitating flow around a composite hydrofoil.
Using deep learning to accelerate magnetic resonance measurements of molecular exchange
Authors: Cheng Zhaowei , Hu Songtao , Han Guangxu , Fang Ke , Jin Xinyu , Ordinola Alfredo , Özarslan Evren , Bai Ruiliang
Published: August 2023

Real-time monitoring and quantitative measurement of molecular exchange between different microdomains are useful to characterize the local dynamics in porous media and biomedical applications of magnetic resonance. Diffusion exchange spectroscopy (DEXSY) is a noninvasive technique for such measurements. However, its application is largely limited by the involved long acquisition time and complex parameter estimation. In this study, we introduce a physics-guided deep neural network that accelerates DEXSY acquisition in a data-driven manner. The proposed method combines sampling pattern optimization and physical parameter estimation into a unified framework. Comprehensive simulations and experiments based on a two-site exchange system are conducted to demonstrate this new sampling optimization method in terms of accuracy, repeatability, and efficiency. This general framework can be adapted for other molecular exchange magnetic resonance measurements.
Nonlinear saturation of whistler modes driven by runaway electrons
Authors: Breizman B. N. , Kiramov D. I.
Published: August 2023

Runaway electrons exhibit kinetic instabilities with potentially beneficial consequences. The anomalous Doppler resonance between the electrons and whistler modes is a primary underlying mechanism. These instabilities require a first-principle nonlinear theoretical analysis, which would ultimately enable assessment of their impact on disruption mitigation and diagnostics, especially in ITER-relevant conditions. This paper presents recent progress in developing the required theoretical framework for isolated nonlinear resonances. By employing the generic bump-on-tail model, we predict the wave saturation levels in both near-threshold and strongly driven regimes. Remarkably, for the waves of interest, the parallel component of the wave vector dictates the parallel momentum of the resonant particles. This feature, together with the expected wave saturation level, provides a complete description of the resonance impact on the runaway electron distribution function. We show that the parametric dependence of the nonlinearly saturated mode provides a way to recover certain features of the runaway momentum distribution function.
Topological analysis of information-theoretic quantities in density functional theory
Authors: He Xin , Lu Tian , Rong Chunying , Liu Shubin , Ayers Paul W. , Liu Wenjian
Published: August 2023

We have witnessed considerable research interest in the recent literature about the development and applications of quantities from the information-theoretic approach (ITA) in density functional theory. These ITA quantities are explicit density functionals, whose local distributions in real space are continuous and well-behaved. In this work, we further develop ITA by systematically analyzing the topological behavior of its four representative quantities, Shannon entropy, two forms of Fisher information, and relative Shannon entropy (also called information gain or Kullback−Leibler divergence). Our results from their topological analyses for 103 molecular systems provide new insights into bonding interactions and physiochemical properties, such as electrophilicity, nucleophilicity, acidity, and aromaticity. We also compare our results with those from the electron density, electron localization function, localized orbital locator, and Laplacian functions. Our results offer a new methodological approach and practical tool for applications that are especially promising for elucidating chemical bonding and reactivity propensity.
Amplified spontaneous emission from europium-based molecular complexes coupled to photonic crystal cavities
Authors: Emmanuele Ruggero , Wang Wei , Smith Ashton , Masson Eric , Gosztola David J. , Rajh Tijana , Hla Saw Wai , Ma Xuedan
Published: August 2023

Rare-earth ion-based materials bear many remarkable optical properties that render them highly appealing for lighting and quantum-related applications. However, their small oscillator strength and weak emission often pose limitations. Here, we synthesize and couple Eu(III)-based molecular complexes to nanobeam photonic crystals supporting air modes. A reasonable spatial overlap between the molecular complexes and cavity modes leads to an average spontaneous emission coupling efficiency of 0.19. Our pump power-dependent photoluminescence measurements evidence amplified spontaneous emission from the molecular complexes with an amplification threshold as low as 4.4 W/cm2, likely benefiting from the efficient coupling. These findings suggest that integrating rare-earth ion-based molecular complexes with photonic structures could be a viable approach for regulating their emission characteristics for particular applications.
Ice adhesion mechanism on the patterned surface of aluminum matrix and array graphene based on molecular dynamics simulations
Authors: Zhao Lingfeng , Liu Weilan , Shen Yizhou , Xu Yangjiangshan , Jiang Biao , Tao Jie
Published: August 2023

Solving fundamental problems in engineering application can drive rapid industrial development. The solid–ice interface adhesion mechanism on anti-icing materials has attracted strong interest from researchers. In this work, the ice adhesion mechanism at the solid–ice interface was investigated based on water molecule behavior on an aluminum matrix/array graphene (M/G) surface. We counted the number of water molecules in the gaps of the array graphene structure and measured ice and array graphene of stress changes during ice removal. The multilayer array graphene structure relies on “adhesion-type” ice removal mechanism. It was attributed to the increased horizontal displacement of ice due to the stress matching of ice/array graphene. The solid-ice interface adhesion mechanism of patterned surface is understood at the molecular-scale.
Stable electroluminescence in ambipolar dopant-free lateral p–n junctions
Authors: Tian Lin , Sfigakis Francois , Shetty Arjun , Kim Ho-Sung , Sherlekar Nachiket , Hosseini Sara , Tam Man Chun , van Kasteren Brad , Buonacorsi Brandon , Merino Zach , Harrigan Stephen R. , Wasilewski Zbigniew , Baugh Jonathan , Reimer Michael E.
Published: August 2023

Dopant-free lateral p–n junctions in the GaAs/AlGaAs material system have attracted interest due to their potential use in quantum optoelectronics (e.g., optical quantum computers or quantum repeaters) and ease of integration with other components, such as single electron pumps and spin qubits. A major obstacle to integration has been the unwanted charge accumulation at the p–n junction gap that suppresses light emission, either due to enhanced non-radiative recombination or due to inhibition of p–n current. Typically, samples must frequently be warmed to room temperature to dissipate this built-up charge and restore light emission in a subsequent cooldown. Here, we introduce a practical gate voltage protocol that clears this parasitic charge accumulation, in situ at low temperature, enabling the indefinite cryogenic operation of devices. This reset protocol enabled the optical characterization of stable, bright, dopant-free lateral p–n junctions with electroluminescence linewidths among the narrowest (<1 meV; <0.5 nm) reported in this type of device. It also enabled the unambiguous identification of the ground state of neutral free excitons (heavy and light holes) as well as charged excitons (trions). The free exciton emission energies for both photoluminescence and electroluminescence are found to be nearly identical (within 0.2 meV or 0.1 nm). The binding and dissociation energies for free and charged excitons are reported. A free exciton lifetime of 237 ps was measured by time-resolved electroluminescence, compared to 419 ps with time-resolved photoluminescence.
Squeeze flow of a Maxwell fluid between two parallel disks or two spheres
Authors: Zheng Zhaolin , Xie Haiou , Chen Xuedong , Liu Xuhui , Yang Wei , Xu Yong , Huang Wenbin
Published: August 2023

In this study, we investigated the squeeze flow of an upper convected Maxwell fluid between two rigid disks or spheres. It has been proved that the velocity field of the Maxwell squeeze flow between two disks is similar to Newtonian at low Deborah numbers. Based on the Newtonian fluid velocity field, we analyze the pressure distribution between two parallel disks and develop a theoretical model of normal squeeze force. We also use the same method to analyze the interaction between two nearly contacting, arbitrary rigid spheres. We obtained the analytical expression of the pressure distribution and normal squeeze force, which can be implemented into the contact model for the discrete element simulation of a wet particle system with the Maxwell fluid.
A doping strategy to achieve synergistically tuned magnetic and dielectric properties in MoSe2 for broadband electromagnetic wave absorption
Authors: Wang Hui , Liu Guang , Lu Juetian , Yan Mi , Wu Chen
Published: August 2023

Advanced electromagnetic (EM) wave absorbing materials are essential to tackle the even-increasing EM interference and pollution. Conventional methods usually combine magnetic and dielectric components for optimized impedance matching and attenuation. It is, however, challenging to simultaneously tune magnetic and dielectric properties with one wane and the other wax by adjusting the ratio between the corresponding components. Here, simultaneous modulation of both magnetic and dielectric properties has been achieved via a doping strategy in MoSe2. On the one hand, significant room-temperature ferromagnetism could be induced through the generation and coupling of local magnetic moments of Mn2+. On the other hand, Mn doping also enhances the dielectric properties by promoting the formation of amorphous and 1T phase of doped MoSe2. The synergistic magnetic and dielectric effects give rise to optimal absorption performance with a minimum reflection loss (RLmin) of −54.57 dB and a wide effective absorption bandwidth (EAB) of 8.24 GHz at 2.00 mm. Such comprehensive performance surpasses the majority of the transition metal dichalcogenide (TMD)-based composites and is the best among all the single-component TMD absorbers. Consequently, the study sheds light on synergistic modulation of EM properties in single-component materials, providing prospective solutions in the design of magnetic and dielectric devices for EM wave absorption and other fields, such as sensing, information storing, and quantum computing.
Tunable terahertz metamaterial with multi-resonance characteristic for refractive index sensing application
Authors: Sun Hao , Lin Yu-Sheng
Published: August 2023

A tunable terahertz (THz) metamaterial (TTM) composed of double connected semicircle-shaped rings and two segregated metallic bars is presented. Through the manipulation of the radius of connected semicircle-shaped rings (R), the transverse electric (TE)-polarization resonance is red-shifted from 1.225 to 0.669 THz. The first and second transverse magnetic (TM)-polarization resonances can be systematically red-shifted from 1.225 to 0.669 THz and from 1.787 to 1.162 THz, respectively. By increasing the R value from 15.0 to 27.5 µm, the tuning trend of the free spectral range is linear over the range of 0.50 THz. Moreover, the TTM device shows polarization-dependent characteristics, which can be modulated by manipulating the distance between the semicircular-shaped ring structure and the metallic bar. The electromagnetic responses of the TTM device can be effectively tuned, enabling the possibility to switch between single-resonance in the TE mode, and dual-, triple-, and quad-resonance in the TM mode. The experiment and simulation results are agreed well. The TTM device can be employed as a sensor for evaluating the change of surrounding refractive index. The sensitivities between resonances and refractive indices are linear in the TE and TM modes. Therefore, TTM devices can be used for single-, dual-, triple-, and quad-resonance switching, polarization switching, and high-efficiency environmental sensing applications.
Loss of energetic ions due to n = 1 internal kink instability in HL-2M
Authors: Dong G. Q. , Liu Y. Q. , Hao G. Z. , Wang S. , Zhang N. , Wang Y. Q. , Miao Y. T. , Li C. Y. , Zhao Y. F.
Published: August 2023

Effects of three-dimensional (3D) perturbations due to an unstable n = 1 (n is the toroidal mode number) internal kink (IK) on the energetic particles (EPs) are systematically investigated for the HL-2M tokamak, utilizing the MARS-F/K code [Liu et al., Phys. Plasmas 7, 3681–3690 (2000)] and a recently developed test particle tracing module. A high-beta sawteething HL-2M scenario, simulated by the TRANSP code [Breslau et al., Transp Computer Software (2018)], is chosen for this study. In general, the 3D perturbation associated with an unstable IK is found to affect the EP drift orbit, confinement, and loss in HL-2M. The instability-induced EP loss fraction is found to be typically less than 10%, without counting for the prompt orbit loss associated with the 2D equilibrium field for counter-current particles. The latter reaches about 16% in HL-2M. For co-current EPs, a 100 G 3D magnetic field (inside the plasma) due to the IK does not induce any EP loss assuming a static perturbation. A sawtooth-like time-varying perturbation field, with the peak amplitude reaching 1000 G, can however produce about 30% loss for the co-current EPs in HL-2M. The majority of lost EPs tend to strike the lower divertor region, with a small fraction of particles striking the low-field side mid-plane region of the limiting surface.
Computing geodesic paths encoding a curvature prior for curvilinear structure tracking
Authors: Chen Da , Mirebeau Jean-Marie , Shu Minglei , Cohen Laurent D.
Published: August 2023

In this paper, we introduce an efficient method for computing curves minimizing a variant of the Euler–Mumford elastica energy, with fixed endpoints and tangents at these endpoints, where the bending energy is enhanced with a user-defined and data-driven scalar-valued term referred to as the curvature prior. In order to guarantee that the globally optimal curve is extracted, the proposed method involves the numerical computation of the viscosity solution to a specific static Hamilton–Jacobi–Bellman (HJB) partial differential equation (PDE). For that purpose, we derive the explicit Hamiltonian associated with this variant model equipped with a curvature prior, discretize the resulting HJB PDE using an adaptive finite difference scheme, and solve it in a single pass using a generalized fast-marching method. In addition, we also present a practical method for estimating the curvature prior values from image data, designed for the task of accurately tracking curvilinear structure centerlines. Numerical experiments on synthetic and real-image data illustrate the advantages of the considered variant of the elastica model with a prior curvature enhancement in complex scenarios where challenging geometric structures appear.
Climate determines transmission hotspots of Polycystic Echinococcosis, a life-threatening zoonotic disease, across Pan-Amazonia
Authors: San-José Adrià , Mayor Pedro , Carvalho Bruno , El Bizri Hani R. , Antunes André Pinassi , Antunez Correa Miguel , Aquino Rolando , Bodmer Richard E. , Boubli Jean P. , Carvalho Elildo A. R. , Campos-Silva João Vitor , Constantino Pedro A. L. , de Paula Milton José , Desbiez Arnauld L. J. , Fang Tula , Gómez-Puerta Luis A. , Knoop Simon B. , Longin Guillaume , Morcatty Thais Q. , Maranhão Louise , Massocato Gabriel Favero , Munari Daniel P. , Nunes André Valle , Puertas Pablo , Oliveira Marcela A. , Pezzuti Juarez C. B. , Richard-Hansen Cécile , Santos Geovanna , Valsecchi João , von Mühlen Eduardo M. , Bosmediano John , Rodó Xavier
Published: August 2023

Polycystic Echinococcosis (PE), a neglected life-threatening zoonotic disease caused by the cestodeEchinococcus vogeli,is endemic in the Amazon. Despite being treatable, PE reaches a case fatality rate of around 29% due to late or missed diagnosis. PE is sustained in Pan-Amazonia by a complex sylvatic cycle. The hunting of its infected intermediate hosts (especially the lowland pacaCuniculus paca) enables the disease to further transmit to humans, when their viscera are improperly handled. In this study, we compiled a unique dataset of host occurrences (~86000 records) and disease infections (~400 cases) covering the entire Pan-Amazonia and employed different modeling and statistical tools to unveil the spatial distribution of PE’s key animal hosts. Subsequently, we derived a set of ecological, environmental, climatic, and hunting covariates that potentially act as transmission risk factors and used them as predictors of two independent Maximum Entropy models, one for animal infections and one for human infections. Our findings indicate that temperature stability promotes the sylvatic circulation of the disease. Additionally, we show how El Niño-Southern Oscillation (ENSO) extreme events disrupt hunting patterns throughout Pan-Amazonia, ultimately affecting the probability of spillover. In a scenario where climate extremes are projected to intensify, climate change at regional level appears to be indirectly driving the spillover ofE. vogeli. These results hold substantial implications for a wide range of zoonoses acquired at the wildlife-human interface for which transmission is related to the manipulation and consumption of wild meat, underscoring the pressing need for enhanced awareness and intervention strategies.
Bioinspired nanogels as cell-free DNA trapping and scavenging organelles for rheumatoid arthritis treatment
Authors: Zhu Haofang , Kong Bin , Che Junyi , Zhao Yuanjin , Sun Lingyun
Published: August 2023

Excessive cell-free DNA (cfDNA) in the serum and synovium is considered a causative factor of rheumatoid arthritis (RA). Thus, cfDNA scavenging by using cationic polymers has been an effective therapeutic avenue, while these stratagems still suffer from systemic toxicity and unstable capture of cfDNA. Here, inspired by the biological charge-trapping effects and active degradation function of enzyme-containing organelles in vivo, we proposed a cationic peptide dendrimer nanogel with deoxyribonuclease I (DNase I) conjugation for the treatment of RA. Benefitting from their naturally derived peptide components, the resultant nanogels were highly biocompatible. More attractively, by tailoring them with a larger size and higher surface charge density, these cationic nanogels could achieve the fastest targeting capability, highest accumulation amounts, longer persistence time, and superior DNA scavenging capacity in inflamed joints. Based on these features, we have demonstrated that the organelle mimicking cationic nanogels could significantly down-regulate toll-like receptor (TLR)-9 signaling pathways and attenuate RA symptoms in collagen-induced arthritis mice. These results make the bioinspired DNase I conjugated cationic nanogels an ideal candidate for treating RA and other immune dysregulation diseases.
Multitasking via baseline control in recurrent neural networks
Authors: Ogawa Shun , Fumarola Francesco , Mazzucato Luca
Published: August 2023

Changes in behavioral state, such as arousal and movements, strongly affect neural activity in sensory areas, and can be modeled as long-range projections regulating the mean and variance of baseline input currents. What are the computational benefits of these baseline modulations? We investigate this question within a brain-inspired framework for reservoir computing, where we vary the quenched baseline inputs to a recurrent neural network with random couplings. We found that baseline modulations control the dynamical phase of the reservoir network, unlocking a vast repertoire of network phases. We uncovered a number of bistable phases exhibiting the simultaneous coexistence of fixed points and chaos, of two fixed points, and of weak and strong chaos. We identified several phenomena, including noise-driven enhancement of chaos and ergodicity breaking; neural hysteresis, whereby transitions across a phase boundary retain the memory of the preceding phase. In each bistable phase, the reservoir performs a different binary decision-making task. Fast switching between different tasks can be controlled by adjusting the baseline input mean and variance. Moreover, we found that the reservoir network achieves optimal memory performance at any first-order phase boundary. In summary, baseline control enables multitasking without any optimization of the network couplings, opening directions for brain-inspired artificial intelligence and providing an interpretation for the ubiquitously observed behavioral modulations of cortical activity.
Association of vaccination, international travel, public health and social measures with lineage dynamics of SARS-CoV-2
Authors: Yang Lingyue , Wang Zengmiao , Wang Lin , Vrancken Bram , Wang Ruixue , Wei Yuanlong , Rader Benjamin , Wu Chieh-Hsi , Chen Yuyang , Wu Peiyi , Li Bingying , Lin Qiushi , Dong Lu , Cui Yujun , Shi Mang , Brownstein John S. , Stenseth Nils Chr. , Yang Ruifu , Tian Huaiyu
Published: August 2023

Continually emerging SARS-CoV-2 variants of concern that can evade immune defenses are driving recurrent epidemic waves of COVID-19 globally. However, the impact of measures to contain the virus and their effect on lineage diversity dynamics are poorly understood. Here, we jointly analyzed international travel, public health and social measures (PHSM), COVID-19 vaccine rollout, SARS-CoV-2 lineage diversity, and the case growth rate (GR) from March 2020 to September 2022 across 63 countries. We showed that despite worldwide vaccine rollout, PHSM are effective in mitigating epidemic waves and lineage diversity. An increase of 10,000 monthly travelers in a single country-to-country route between endemic countries corresponds to a 5.5% (95% CI: 2.9 to 8.2%) rise in local lineage diversity. After accounting for PHSM, natural immunity from previous infections, and waning immunity, we discovered a negative association between the GR of cases and adjusted vaccine coverage (AVC). We also observed a complex relationship between lineage diversity and vaccine rollout. Specifically, we found a significant negative association between lineage diversity and AVC at both low and high levels but not significant at the medium level. Our study deepens the understanding of population immunity and lineage dynamics for future pandemic preparedness and responsiveness.
Silk-protein-based gradient hydrogels with multimode reprogrammable shape changes for biointegrated devices
Authors: Wang Yushu , Li Luhe , Ji Yue-E. , Wang Tao , Fu Yinghao , Li Xinxin , Li Guicai , Zheng Tiantian , Wu Linliang , Han Qi , Zhang Ye , Wang Yu , Kaplan David L. , Lu Yanqing
Published: August 2023

Biocompatible and morphable hydrogels capable of multimode reprogrammable, and adaptive shape changes are potentially useful for diverse biomedical applications. However, existing morphable systems often rely on complicated structural designs involving cumbersome and energy-intensive fabrication processes. Here, we report a simple electric-field-activated protein network migration strategy to reversibly program silk-protein hydrogels with controllable and reprogrammable complex shape transformations. The application of a low electric field enables the convergence of net negatively charged protein cross-linking networks toward the anode (isoelectric point plane) due to the pH gradient generated in the process, facilitating the formation of a gradient network structure and systems suitable for three-dimensional shape change. These tunable protein networks can be reprogrammed or permanently fixed by control of the polymorphic transitions. We show that these morphing hydrogels are capable of conformally interfacing with biological tissues by programming the shape changes and a bimorph structure consisting of aligned carbon nanotube multilayers and the silk hydrogels was assembled to illustrate utility as an implantable bioelectronic device for localized low-voltage electrical stimulation of the sciatic nerve in a rabbit.
CLCF1 signaling restrains thermogenesis and disrupts metabolic homeostasis by inhibiting mitochondrial biogenesis in brown adipocytes
Authors: Ding Meng , Xu Hong-yu , Zhou Wei-yu , Xia Yi-fan , Li Bai-yu , Shi Yi-jie , Dou Xin , Yang Qi-qi , Qian Shu-wen , Tang Yan , Pan Dong-ning , Liu Yang , Tang Qi-qun
Published: August 2023

Great progress has been made in identifying positive regulators that activate adipocyte thermogenesis, but negative regulatory signaling of thermogenesis remains poorly understood. Here, we found that cardiotrophin-like cytokine factor 1 (CLCF1) signaling led to loss of brown fat identity, which impaired thermogenic capacity. CLCF1 levels decreased during thermogenic stimulation but were considerably increased in obesity. Adipocyte-specific CLCF1 transgenic (CLCF1-ATG) mice showed impaired energy expenditure and severe cold intolerance. Elevated CLCF1 triggered whitening of brown adipose tissue by suppressing mitochondrial biogenesis. Mechanistically, CLCF1 bound and activated ciliary neurotrophic factor receptor (CNTFR) and augmented signal transducer and activator of transcription 3 (STAT3) signaling. STAT3 transcriptionally inhibited both peroxisome proliferator-activated receptor-γ coactivator (PGC) 1α and 1β, which thereafter restrained mitochondrial biogenesis in adipocytes. Inhibition of CNTFR or STAT3 could diminish the inhibitory effects of CLCF1 on mitochondrial biogenesis and thermogenesis. As a result, CLCF1-TG mice were predisposed to develop metabolic dysfunction even without external metabolic stress. Our findings revealed a brake signal on nonshivering thermogenesis and suggested that targeting this pathway could be used to restore brown fat activity and systemic metabolic homeostasis in obesity.
Engineering a complex, multiple enzyme-mediated synthesis of natural plant pigments in the silkworm,
Bombyx mori
Authors: Chen Kai , Yu Ye , Zhang Zhongjie , Hu Bo , Liu Xiaojing , James Anthony A. , Tan Anjiang
Published: August 2023

Plants produce various pigments that not only appear as attractive colors but also provide valuable resources in applications in daily life and scientific research. Biosynthesis pathways for these natural plant pigments are well studied, and most have multiple enzymes that vary among plant species. However, adapting these pathways to animals remains a challenge. Here, we describe successful biosynthesis of betalains, water-soluble pigments found only in a single plant order, Caryophyllales, in transgenic silkworms by coexpressing three betalain synthesis genes, cytochrome P450 enzyme
CYP76AD1
,
DOPA 4,5-dioxygenase,
and
betanidin 5-O-glucosyltransferase
. Betalains can be synthesized in various tissues under the control of the ubiquitous IE1 promoter but accumulate mainly in the hemolymph with yields as high as 274 μg/ml. Additionally, transformed larvae and pupae show a strong red color easily distinguishable from wild-type animals. In experiments in which expression is controlled by the promoter of silk gland-specific gene,
fibroin heavy-chain
, betalains are found predominantly in the silk glands and can be secreted into cocoons through spinning. Betalains in transformed cocoons are easily recovered from cocoon shells in water with average yields reaching 14.4 μg/mg. These data provide evidence that insects can synthesize natural plant pigments through a complex, multiple enzyme-mediated synthesis pathway. Such pigments also can serve as dominant visible markers in insect transgenesis applications. This study provides an approach to producing valuable plant-derived compounds by using genetically engineered silkworms as a bioreactor.
NTRC regulates CP12 to activate Calvin–Benson cycle during cold acclimation
Authors: Teh Jing Tsong , Leitz Verena , Holzer Victoria J. C. , Neusius Daniel , Marino Giada , Meitzel Tobias , García-Cerdán José G. , Dent Rachel M. , Niyogi Krishna K. , Geigenberger Peter , Nickelsen Jörg
Published: August 2023

NADPH-dependent thioredoxin reductase C (NTRC) is a chloroplast redox regulator in algae and plants. Here, we used site-specific mutation analyses of the thioredoxin domain active site of NTRC in the green alga
Chlamydomonas reinhardtii
to show that NTRC mediates cold tolerance in a redox-dependent manner. By means of coimmunoprecipitation and mass spectrometry, a redox- and cold-dependent binding of the Calvin–Benson Cycle Protein 12 (CP12) to NTRC was identified. NTRC was subsequently demonstrated to directly reduce CP12 of
C. reinhardtii
as well as that of the vascular plant
Arabidopsis thaliana
in vitro. As a scaffold protein, CP12 joins the Calvin–Benson cycle enzymes phosphoribulokinase (PRK) and glyceraldehyde-3-phosphate dehydrogenase (GAPDH) to form an autoinhibitory supracomplex. Using size-exclusion chromatography, NTRC from both organisms was shown to control the integrity of this complex in vitro and thereby PRK and GAPDH activities in the cold. Thus, NTRC apparently reduces CP12, hence triggering the dissociation of the PRK/CP12/GAPDH complex in the cold. Like the
ntrc::aphVIII
mutant, CRISPR-based
cp12::emx1
mutants also exhibited a redox-dependent cold phenotype. In addition,
CP12
deletion resulted in robust decreases in both PRK and GAPDH protein levels implying a protein protection effect of CP12. Both CP12 functions are critical for preparing a repertoire of enzymes for rapid activation in response to environmental changes. This provides a crucial mechanism for cold acclimation.
Uncoupling of Ca
2+
sparks from BK channels in cerebral arteries underlies hypoperfusion in hypertension-induced vascular dementia
Authors: Taylor Jade L. , Walsh Katy R. , Mosneag Ioana-Emilia , Danby Thea G. E. , Luka Nadim , Chanda Bishal , Schiessl Ingo , Dunne Ross A. , Hill-Eubanks David , Hennig Grant W. , Allan Stuart M. , Nelson Mark T. , Greenstein Adam S. , Pritchard Harry A. T.
Published: August 2023

The deficit in cerebral blood flow (CBF) seen in patients with hypertension-induced vascular dementia is increasingly viewed as a therapeutic target for disease-modifying therapy. Progress is limited, however, due to uncertainty surrounding the mechanisms through which elevated blood pressure reduces CBF. To investigate this, we used the BPH/2 mouse, a polygenic model of hypertension. At 8 mo of age, hypertensive mice exhibited reduced CBF and cognitive impairment, mimicking the human presentation of vascular dementia. Small cerebral resistance arteries that run across the surface of the brain (pial arteries) showed enhanced pressure-induced constriction due to diminished activity of large-conductance Ca
2+
-activated K
+
(BK) channels—key vasodilatory ion channels of cerebral vascular smooth muscle cells. Activation of BK channels by transient intracellular Ca
2+
signals from the sarcoplasmic reticulum (SR), termed Ca
2+
sparks, leads to hyperpolarization and vasodilation. Combining patch-clamp electrophysiology, high-speed confocal imaging, and proximity ligation assays, we demonstrated that this vasodilatory mechanism is uncoupled in hypertensive mice, an effect attributable to physical separation of the plasma membrane from the SR rather than altered properties of BK channels or Ca
2+
sparks, which remained intact. This pathogenic mechanism is responsible for the observed increase in constriction and can now be targeted as a possible avenue for restoring healthy CBF in vascular dementia.
Social learning and memory
Authors: Ammar Madeleine , Fogarty Laurel , Kandler Anne
Published: August 2023

The adaptability of human populations to changing environments is often attributed to the human capacity for social learning, innovation, and culture. In rapidly changing environments, it has been shown that maintaining high levels of cultural variation is beneficial because it allows for efficient adaptation. However, in many theoretical models, a high level of cultural variation also implies that a large amount of useless and perhaps detrimental information must be maintained and used, leading to lower population fitness in general. Here, we begin to investigate this often conflicting relationship between adaptation and cultural variation. We explicitly allow for the interplay between social learning and environmental variability, alongside the capacity for “memory,” i.e., the storage, retrieval, and forgetting of information. Here, memory allows individuals to retain unexpressed cultural variation, which does not directly impact adaptation. We show that this capacity for memory facilitates the evolution of social learning across a broader range of circumstances than previously thought. Results from this analysis may help to establish whether and when memory should be incorporated into cultural evolutionary models focused on questions of adaptation.
Modelling the laser surface hardening in a ferrite and pearlite initial microstructure
Authors: Castro Cerda Felipe M. , Goulas Constantinos , Jones Dakota , Kamyabi Ata , Hamre Douglas , Méndez Patricio , Wood Gentry
Published: August 2023

The present study explores the microstructure and the depth-dependence of hardness after a single pass laser heat-treatment. The initial microstructure was selected as ferrite and pearlite in different fractions, with the aim of studying low, medium, and high carbon steels. A modification of an existing model is proposed, whereby the cementite dissolution is incorporated to better reflect the microstructure evolution during the rapid thermal cycle. It is found that the predictions under the new paradigm show fair agreement with the experimental data. The new model indicates that the correct estimation of the composition of austenite near the transition zone produces a more accurate prediction of the hardness profile, reducing the overestimation obtained in previous works.
Experimental study on physical characteristics of dielectric-boosted gliding arc discharge
Authors: Meng Xiangyi , Lu Na , Cheng Shiye , Li Yubing , Liu Dongping , Shang Kefeng , Jiang Nan
Published: August 2023

To augment the plasma processing capability, and obtain an enhanced plasma area, a dielectric-boosted gliding arc discharge (DBGAD) reactor was developed. The electrical, gliding arc motion and energy injection characteristics of the DBGAD reactor were investigated. The process of AC DBGAD includes breakdown gliding mode (B-G) and steady arc gliding mode (A-G), with peak currents on the order of amperes in B-G mode and on the order of milliamps in A-G mode. Situating a 50 mm quartz dielectric underneath the plasma area at a distance of 10 mm from the base of the blade electrodes, enhanced discharge power is obtained, and sustained arc gliding time is extended efficiently. At an input voltage of 9.2 kV, the DBGAD demonstrates a 27% increase in arc stabilization gliding time compared to the gliding arc discharge (GAD) and delivers an average discharge power 1.12 times superior to that of the GAD. In the DBGAD reactor, the plasma column twists following the minor vortex of the reflow and has a more pleated shape. The energy injection characteristics are analyzed using the fast Fourier transform system, and the results show that the current harmonic content of DBGAD is reduced and the discharge fluctuation is mitigated, which is favorable for stable discharge. The primary benefit of incorporating quartz dielectric is that it provides the mobile arc with a supportive force, leading to a more substantial and intensely focused plasma field. This in turn facilitates greater system stability and yields measurable enhancements in power output.
Bound states in the continuum driven by multiple modes for high Q refractive index sensing in metasurfaces
Authors: Li Jiangbin , Wang Zhihui , Liu Haiying
Published: August 2023

Bound states in the continuum (BICs) have attracted much attention in the field of refractive index sensing. In this paper, we propose multi-mode symmetry-protected BICs (SP-BICs) and the Freidrich–Wintgen BIC (FW-BIC) in terahertz metasurfaces consisted of periodic open split ring resonators. Firstly, multi-mode SP-BICs are subject to the magnetic dipole, electric dipole (ED), and toroidal dipole (TD) modes. Moreover, we demonstrate the FW-BIC by strongly coupling the electric quadrupole and TD modes. For micron film sensing of the ED mode, simulation results show that the Q factor, the sensitivity of sensing (S), and the corresponding figure of merit can simultaneously reach 1561, 141 GHz/RIU, and 306, respectively. Our quasi-BICs have potential applications in micro-sensing.
Dynamic radar jamming metasurface with amplitude and phase modulation
Authors: Guo Zhiqing , Bian Li-an , Lin Mingtuan , Chen Ranhao , Li Yanxiu , Huang Yuanxin
Published: August 2023

In this paper, a one-bit coding metasurface comprised of 20 columns is proposed to achieve amplitude and phase modulation. Each column is dynamically controlled by p-i-n diodes to modulate the incident electromagnetic waves. By synthesizing the code sequence, the radar cross section (RCS) of the surface can be reduced to specific values. With shift coding and inverse code sequence, the metasurface can also achieve phase modulation function with almost the same amplitude responses. A metasurface prototype is fabricated and measured, showing an obvious RCS reduction in a 35.2% bandwidth from 7 to 10 GHz. Specifically, a high RCS reduction of 23 dB can be achieved at 8.5 GHz. In addition, the metasurface exhibits the capability of phase modulation with responses of

60
±

15
∘

and

140
±

30
∘

, while the amplitude responses are almost the same. Overall, the proposed dynamic metasurface is useful for radar jamming, which is expected to further improve the stealth performance of the target.
Structure and energetics of FeO/Fe(001) interfaces
Authors: Ossowski Tomasz , Kiejna Adam
Published: August 2023

We report results of density functional theory calculations of structure and properties of 1–5 monolayer thin FeO(001) films and their interactions with the Fe(001) surface. It is found that deposition of an iron-oxide film affects weakly geometry of the Fe(001) support, causing small

<

2% expansion of the first interplanar distance compared to clean iron surface. Analysis of the electronic structure of the FeO/Fe system shows that after interface formation, the oxide layer remains semiconducting and the substrate metallic. Electronic structure of the FeO(001) layer in direct contact with the Fe(001) surface exhibits metallic character. Magnetism of the metal/semiconductor interface is only slightly disturbed compared to that of isolated components. The FeO adlayers preserve antiferromagnetic (AFM) nature of the oxide and the sharp boundary between higher AFM phase of FeO and lower ferromagnetic phase of Fe is observed at the interface.
3D-ordered porous CdS/AgI/ZnO nanostructures for high-performance photoelectrochemical water splitting
Authors: Hieu Hoang Nhat , Nguyen Van Nghia , Nguyen Vuong Minh , Phan Thanh Hai
Published: August 2023

3D-ordered porous CdS/AgI/ZnO nanostructures were designed to perform as high-performance photoelectrodes for photoelectrochemical (PEC) water-splitting applications. They rely on the advantages of an extremely large active surface area, high absorption capacity in the visible-light region, fast carrier separation and transportation caused by the intrinsic ladder-like band arrangement. These nanostructures were fabricated by employing a three-stage experiment in a sequence of hard mold-assisted electrochemical deposition, wet chemical method and deposition–precipitation. First, 3D-ordered ZnO nanostructures were electrochemically deposited using a polystyrene film as the sacrificed template. AgI nanoparticles were then decorated on the interfacial ZnO nanostructures by deposition–precipitation. Finally, these binary AgI/ZnO nanoporous networks were thoroughly wet-chemically coated with a CdS film to form a so-called ‘ternary interfacial CdS/AgI/ZnO nanostructures’. The PEC water-splitting properties of the fabricated 3D nanostructures were systematically studied and compared. As a result, the highest efficiency of the fabricated 3D-ordered porous CdS/AgI/ZnO measured under the irradiation of solar simulation is about 5.2%, which is relatively 1.5, 3.5 and 11.3 times greater than that of the corresponding CdS/ZnO (3,4%), AgI/ZnO (1.5%) and pristine porous ZnO (0.46%) photoelectrodes, respectively. The significant improvement in the PEC activity is attributed to the enhanced charge separation and transport of ternary photoelectrodes caused by an unconventional ladder-like band arrangement formed between interfacial CdS-AgI-ZnO. Our study provides a promising strategy for developing such ternary photoelectrode generation that possesses higher stability and efficiency towards water-splitting processes.