bluuebunny/crossref_metadata_2025 huggingface dataset:
Large language models for automatic equation discovery of nonlinear dynamics
Authors: Du Mengge , Chen Yuntian , Wang Zhongzheng , Nie Longfeng , Zhang Dongxiao
Published: September 2024

Equation discovery aims to directly extract physical laws from data and has emerged as a pivotal research domain in nonlinear systems. Previous methods based on symbolic mathematics have achieved substantial advancements, but often require handcrafted representation rules and complex optimization algorithms. In this paper, we introduce a novel framework that utilizes natural language-based prompts to guide large language models (LLMs) in automatically extracting governing equations from data. Specifically, we first utilize the generation capability of LLMs to generate diverse candidate equations in string form and then evaluate the generated equations based on observations. The best equations are preserved and further refined iteratively using the reasoning capacity of LLMs. We propose two alternately iterated strategies to collaboratively optimize the generated equations. The first strategy uses LLMs as a black-box optimizer to achieve equation self-improvement based on historical samples and their performance. The second strategy instructs LLMs to perform evolutionary operations for a global search. Experiments are conducted on various nonlinear systems described by partial differential equations, including the Burgers equation, the Chafee–Infante equation, and the Navier–Stokes equation. The results demonstrate that our framework can discover correct equations that reveal the underlying physical laws. Further comparisons with state-of-the-art models on extensive ordinary differential equations showcase that the equations discovered by our framework possess physical meaning and better generalization capability on unseen data.
Kinetics of monolayer MoS2-encapsulated nanobubbles on hexagonal boron nitride substrates
Authors: Liu Zihan , Jiang Yingchun , Wang Dingli , Lai Junpeng , Zhou Huimin , Deng Jia , Ke Changhong
Published: September 2024

Understanding the kinetics of nanobubbles encapsulated by ultrathin two-dimensional (2D) layered van der Waals crystal membranes on atomically flat substrates is important to the applications of 2D materials and the pursuit of 2D nanobubble technologies. Here, we investigate the controlled motion of monolayer molybdenum disulfide (MoS2)-encapsulated nanobubbles on flat hexagonal boron nitride substrates using atomic force microscopy (AFM). Our study reveals a distinct transition from standstill bubble deformations to stable, stepwise bubble translations on flat substrates. The membrane tension-dominated 2D nanobubble behaves like an elastic soft body in its collision interaction with the AFM tip. This delicate motion-control technique enables neighboring 2D nanobubbles to move closer and eventually coalesce into larger nanobubbles. These findings pave the way for high-precision manipulation of nanobubbles and facilitate the exploration of their emerging applications.
Gallium nitride-based resonant tunneling diode oscillators
Authors: Murayama Masahiro , Motobayashi Hisayoshi , Hoshina Yukio , Shoji Miwako , Takiguchi Yoshiro , Miyahara Hiroyuki , Koyama Takahiro , Futagawa Noriyuki
Published: September 2024

We demonstrated GaN-based resonant tunneling diode (RTD) oscillators employing monolithic microwave integrated circuits. The GaN-based RTDs with a GaN quantum well and AlN double barriers were grown on freestanding c-plane semi-insulating GaN substrates using metal–organic chemical vapor deposition. The circuit components, including an RTD, a coplanar waveguide, a metal–insulator–metal capacitor, and shunt resistors, were monolithically fabricated on the GaN substrate. The circuits oscillated at a fundamental frequency of 17 GHz, which closely matched an estimated frequency using a three-dimensional electromagnetic simulator and a circuit simulator. This study contributes to the advancement of semiconductor high-frequency devices for millimeter wave and terahertz applications.
Experiments on critical behavior of oblique detonation wave in stratified mixtures
Authors: Iwata K. , Hanyu N. , Maeda S. , Obara T.
Published: September 2024

Two-stage gas-gun ballistic experiments are performed to investigate the feasibility of stratified mixtures with variable global equivalence ratios Φglobal for the formation of sphere-induced oblique detonation wave (ODW) and quantify their critical behaviors, which include local quenching and transitional structure to ODW, by testing conventional detonation criteria for uniform mixtures. 2 Φglobal H2 + O2 + 3Ar mixtures are tested with different concentration gradients for each fuel-lean/fuel-rich global composition. Opposite responses are observed depending on the global equivalence ratio: the lean mixture of Φglobal = 0.7, which forms ODW in the uniform mixture, fails partly in the strongest stratification, whereas the richest mixture of Φglobal = 2.0 turns to ODW in the strongly stratified conditions. As elucidated in the authors' previous work, Chapman–Jouguet (C–J) theory, including the curvature effects, reproduces the wave angles of the stable ODWs, as well as provides a good prediction on the local quenching of ODW occurring in the area with less reactive composition. Comparison of different wave regimes observed in the explored conditions reveals that wave curvature governs the critical behaviors of ODW far away from the projectile, whereas the initiation structure around the projectile is also influenced by the non-dimensional diameter. Surface energy theory is proven to quantify well the initiation structure on the projectile using a local equivalence ratio. These results indicate a new possibility of controlling the methodology of ignition and stabilization of detonation in aerospace engines, in which perfect mixing is difficult and non-stoichiometric and non-uniform mixtures are expected.
An improved smoothed particle hydrodynamics method for modeling multiphase flows
Authors: Li Yongze , Long Ting
Published: September 2024

Multiphase flows are prevalent in both natural and engineered systems. The study of multiphase flow problems using numerical simulation is challenging due to the presence of high nonlinearities and moving interfaces. In this paper, an improved multiphase smoothed particle hydrodynamics (SPH) model is proposed for simulating multiphase flows. In the improved multiphase SPH model, an improved interface repulsive force model is proposed to reduce the interpenetration of particles at the multiphase interface and make the multiphase interface smooth and clear, and an improved kernel gradient correction is introduced to optimize the computational results. In addition, the particle shifting technology is applied to make the particle distribution uniform. Five numerical examples including the Rayleigh–Taylor instability, non-Boussinesq lock-exchange problem, square droplet deformation, single bubble rise, and circular droplet oscillation are investigated to verify the correctness and effectiveness of the improved multiphase SPH model. The results demonstrate that the improved multiphase SPH approach is effective in modeling multiphase flows.
Influence of contact angle hysteresis on forced oscillations of a clamped drop
Authors: Alabuzhev Aleksey A.
Published: September 2024

We consider forced oscillations of a clamped liquid drop. The drop is surrounded by an incompressible fluid of a different density. In equilibrium, the drop has the form of a circular cylinder bounded axially by parallel solid planes, and the contact angle measures 90°. The specific boundary conditions are applied as follows: the contact line starts to slide only when the deviation of the contact angle exceeds a certain critical value. As a result, the stick-slip dynamics can be observed.
Dipole-assisted hole injection for efficient blue quantum dot light-emitting diodes
Authors: Zhang Youwei , Xiao Xiangtian , Xu Ruiqiang , Ma Jingrui , Lu Fumin , Ye Yifan , Zhang Xiaoli , Wang Kai , Sun Xiao Wei
Published: September 2024

Quantum dot light-emitting diodes (QLEDs) present commercial potential and application prospects in both lighting and display technologies. Blue quantum dots (QDs) possess a substantial bandgap and a profound valence band. The significant potential barrier between blue quantum dots and the hole transport layer leads to an imbalance in charge transfer, thereby adversely impacting the device performance. Self-assembled monolayers are attractive for carrier transport. Here, a dynamic self-assembly method is introduced, doping [2-(9H-carbazol-9-yl)ethyl]phosphonic acid (2PACz) into Poly(3,4-ethylenedioxythiophene)-poly(styrenesulfonate) (PEDOT:PSS) to form electric dipoles at interfaces, realizing better energy level alignment and hole injection rate. The maximum external quantum efficiency rises from 8.77% to 17.26% with 2PACz: PEDOT:PSS strategy, representing a twofold enhancement. This result demonstrates that small molecules undergo dynamic self-assembled bilateral motions during crystallization process, aligning energy levels and passivating interfacial trap states, thereby endowing blue QLEDs with high brightness and high efficiency. This work offers a viable pathway for broader applications of blue QLEDs.
Capillary-driven migration of droplets on conical fibers
Authors: Mao Yixiao , Zhao Chengxi , Mu Kai , Li Kai , Si Ting
Published: September 2024

A droplet placed on a hydrophilic conical fiber tends to move toward the end of larger radii due to capillary action. Experimental investigations are performed to explore the dynamics of droplets with varying viscosities and volumes on different fibers at the microscale. Droplets are found to accelerate initially and subsequently decelerate during migration. A dynamic model is developed to capture the dynamics of droplet migration, addressing the limitations of previous equilibrium-based scaling laws. Both experimental results and theoretical predictions indicate that droplets on more divergent fibers experience a longer acceleration phase. Additionally, gravitational effects are pronounced on fibers with small cone angles, exerting a substantial influence on droplet migration even below the capillary scale. Moreover, droplets move more slowly on dry fibers compared to those prewetted with the same liquid, primarily attributed to increased friction. The experiments reveal the formation of a residual liquid film after droplet migration on dry fibers, leading to considerable volume loss in the droplets. To encompass the intricacies of migration on dry fibers, the model is refined to incorporate a higher friction coefficient and variable droplet volumes, providing a more comprehensive depiction of the underlying physics.
A model for zwitterionic polymers and their capacitance applications
Authors: Bruch Dorian , Wang Zhen-Gang
Published: September 2024

Zwitterions have been shown experimentally to enhance the dielectric constant of ionic media, owing to their large molecular dipole. Many studies since explored the enhancement of ionic conductivity with zwitterion additives as well as bulk behavior of zwitterions. Here, we examine the capacitance behavior of zwitterions between charged parallel plates using a mean-field theory. Employing only chain connectivity of a cation and anion with neutral monomers in between with mean-field electrostatics, we show that our model captures the high-dielectric behavior of zwitterions. We also predict an optimum in the capacitance of zwitterionic media as a function of chain length. To address the issue of zwitterion screening near charged surfaces, we demonstrate that zwitterions simultaneously partially screen charged walls and act as a pure dielectric that propagates the electric field far from the surface. Moreover, we show that salt solutions with zwitterionic additives outperform the energy density of both salt-only and zwitterion-only capacitors. We find that salt-only capacitors perform better at low applied potential, whereas salt capacitors with zwitterionic additives perform better at high applied potential.
Study on the cracking process of epoxy resin under oxygen and water atmosphere based on ReaxFF force field
Authors: Rao Xiajin , Peng Boya , Zhang Lei , Li Dajian , Zhang Wei , Liu Peng , Han Fangyuan , Chen Liangyuan , Su Yi , Wang Le , Pan Shaoming , Li Rui , Huang Wei , Yu Min
Published: September 2024

Amino-cured epoxy resins are widely used in the electrical and electronic industry for their excellent properties. To investigate the mechanism of the effect of O2 and H2O on the pyrolysis behavior of epoxy resin, in this paper, the cross-linked structure of bisphenol A type epoxy resin cured by adducts of diethylenetriamine and butyl glycidyl ether is modeled based on the ReaxFF force field, and the thermal decomposition processes at different temperatures and gas atmospheres were simulated and the pathways of the small molecule products were clarified. The results show that epoxy resin will produce small molecule gas products, such as H2, CO, H2O, OH, CH2O, and free radicals, in the process of pyrolysis; the presence of amino groups also generates nitrogen-containing radicals, such as CN, CH2N, and C2H4N; as the reaction temperature increases, the rate of pyrolysis reaction will be accelerated. The same temperature in oxygen and water atmospheres can accelerate the breakage of epoxy resin main chain by promoting the breakage of carbon and oxygen bonds and, at the same time, promote the generation of small molecule gases, such as H2 and CO.
Space charge-induced capacitance recovery in blue quantum dot light-emitting diodes
Authors: Qu Xiangwei , Ma Jingrui , Li Depeng , Wang Kai , Sun Xiao Wei
Published: September 2024

In this work, we report the capacitance recovery behavior in the blue quantum dot light-emitting diode (QLED) by capacitance–voltage (C–V) characterizations. A comprehensive study of the C–V, dC/dV–V, and current density–voltage characteristics of pristine and shelf-aged devices suggests that capacitance recovery is associated with space charge-induced charge accumulation. At lower temperatures, the capacitance recovery in the shelf-aged device is efficiently suppressed due to the difficulty in building up the space charge, which supports our argument. Moreover, the capacitance recovery behavior of QLED only happens at low frequencies (a few hundred hertz), which is related to the time constant for charge accumulation at the selected voltage. Our work shows the effect of space charge on device capacitance and enriches the comprehension of carrier processes in QLED under AC measurement.
Liquid water radiolysis induced by secondary electrons generated from MeV-energy carbon ions
Authors: Tsuchida Hidetsugu , Tezuka Tomoya , Kai Takeshi , Matsuya Yusuke , Majima Takuya , Saito Manabu
Published: September 2024

Fast ion beams induce damage to deoxyribonucleic acid (DNA) by chemical products, including secondary electrons, produced from interaction with liquid water in living cells. However, the production process of these chemical products in the Bragg peak region used in particle therapy is not fully understood. To investigate this process, we conducted experiments to evaluate the radiolytic yields produced when a liquid water jet in vacuum is irradiated with MeV-energy carbon beams. We used secondary ion mass spectrometry to measure the products, such as hydronium cations (H3O+) and hydroxyl anions (OH−), produced along with ·OH radicals, which are significant inducers of DNA damage formation. In addition, we simulated the ionization process in liquid water by incident ions and secondary electrons using a Monte Carlo code for radiation transport. Our results showed that secondary electrons, rather than incident ions, are the primary cause of ionization in water. We found that the production yield of H3O+ or OH− was linked to the frequency of ionization by secondary electrons in water, with these electrons having energies between 10.9 and 550 eV. These electrons are responsible for ionizing the outer-shell electrons of water molecules. Finally, we present that the elementary processes contribute to advancing radiation biophysics and biochemistry, which study the formation mechanism of DNA damage.
Quantification of geometric uncertainty on hypersonic aerodynamics in scramjet inlets
Authors: Liu Hongkang , Peng Kehui , Zhang Youjun , Sun Di , Zhao Yatian
Published: September 2024

Geometric deviations arising from manufacturing and assembly processes can significantly impact the aerodynamic stability of scramjet inlets. This study aims to quantify the uncertainty and sensitivity of the inlet aerodynamics caused by geometric deviations. Specifically, three representative operating modes are considered: start, half-start, and unstart. Five geometric parameters are extracted as random uncertain variables, including the first and second ramp angle (α1, α2), the horizontal and vertical distance between the lip point and the throat point (dh, dv), and the inner angle of the cowl lip (α3). To achieve the quantification objective, the non-intrusive polynomial chaos method is employed for uncertainty quantification. Sobol indices are utilized to assess the impact of each geometric parameter on the uncertainty of quantities of interest. Results indicate that geometric deviations for only ±1% can have a significant impact on the aerodynamic performance of the inlet. Specifically, the pressure uncertainty in the shock region is more than four times that of the non-shock region, exceeding 40%. With respect to the performance parameters, the mass capture ratio demonstrates a high sensitivity to geometric deviations, with the uncertainty for 6.76%. Sensitivity analysis indicates that the three primary factors affecting the aerodynamic stability within the isolator are dv, α2, and dh. Therefore, deviations in their manufacturing and assembly should be strictly controlled.
Dispersion of a non-uniform solute slug in pulsatile viscoelastic fluid flow
Authors: Rana Jyotirmoy , Das Prosanjit , Sarifuddin  , Mandal Prashanta Kumar , Patne Ramkarn
Published: September 2024

Solute transport in pulsatile viscoelastic fluid flow is relevant in nutrient transport and drug delivery in blood flow. Previous studies have extensively analyzed the effect of the shear-thinning nature of the blood but neglected the elastic property. The present study aims to fill this lacuna by analyzing the role of blood viscoelasticity on solute transport. To accomplish this, we study solute transport for a non-uniformly distributed solute slug in the pulsatile flow of an Oldroyd-B fluid through a tube in the presence of wall absorption. We employ Gill's procedure and Aris' method of moments to compute the transport coefficients Km(t) (m≤4). We also numerically solve the species transport equation using a finite difference scheme to directly determine local solute concentration C(t,z,r). Consistent results for a non-viscoelastic fluid predict a negative convection coefficient K1 and a positive effective diffusivity K2 for realistic values of the parameters. However, the present analysis predicts positive K1 and negative K2 for small tubes due to flow reversal caused by the fluid elasticity. For high Λ1, the amplitude of oscillation for K1 and K2 exhibits scaling K1∼Λ11.5 and K2∼Λ12 indicating an enhancement in the dispersion due to fluid elasticity, where Λ1 is the dimensionless relaxation time. The analysis of the skewness and (excess) kurtosis coefficients reveals inconsistency in previous studies on Newtonian fluids. Thus, we present consistent results not only for a viscoelastic fluid but also for a Newtonian fluid subjected to a pulsatile pressure gradient. In addition, the solute dispersion is significantly influenced by the non-uniformity of a solute slug. As the radius of a slug increases, solute dispersion reduces in short and moderate times; however, at large times, it is independent of the radius of a slug.
Magnetic tunnel junctions with superlattice barriers
Authors: Su Jing-Ci , Cheng Shih-Hung , Huang Sin-You , Hsueh Wen-Jeng
Published: September 2024

The urgent demand for high-performance emerging memory, propelled by artificial intelligence in internet of things (AIoT) and machine learning advancements, spotlights spin-transfer torque magnetic random-access memory as a prime candidate for practical application. However, magnetic tunnel junctions (MTJs) with a single-crystalline MgO barrier, which are central to magnetic random-access memory (MRAM), suffer from significant drawbacks: insufficient endurance due to breakdown and high writing power requirements. A superlattice barrier-based MTJ (SL-MTJ) is proposed to overcome the limitation. We first fabricated the MTJ using an SL barrier while examining the magnetoresistance and resistance-area product. Lower writing power can be achieved in SL-MTJs compared to MgO-MTJs. Our study may provide a new route to the development of MRAM technologies.
On particle dispersion statistics using unsupervised learning and Gaussian mixture models
Authors: Christakis Nicholas , Drikakis Dimitris
Published: September 2024

Understanding the dispersion of particles in enclosed spaces is crucial for controlling the spread of infectious diseases. This study introduces an innovative approach that combines an unsupervised learning algorithm with a Gaussian mixture model to analyze the behavior of saliva droplets emitted from a coughing individual. The algorithm effectively clusters data, while the Gaussian mixture model captures the distribution of these clusters, revealing underlying sub-populations and variations in particle dispersion. Using computational fluid dynamics simulation data, this integrated method offers a robust, data-driven perspective on particle dynamics, unveiling intricate patterns and probabilistic distributions previously unattainable. The combined approach significantly enhances the accuracy and interpretability of predictions, providing valuable insights for public health strategies to prevent virus transmission in indoor environments. The practical implications of this study are profound, as it demonstrates the potential of advanced unsupervised learning techniques in addressing complex biomedical and engineering challenges and underscores the importance of coupling sophisticated algorithms with statistical models for comprehensive data analysis. The potential impact of these findings on public health strategies is significant, highlighting the relevance of this research to real-world applications.
A perspective on magnetic field-enhanced electrocatalytic water splitting
Authors: Zhang Yuanyuan , Chen Mengxin , Chen Ji , Zhang Mingyi , Xu Ping
Published: September 2024

Magnetic field effects have received widespread attention due to their ability to enhance the process of water splitting at multiple scales. However, a systematic and comprehensive understanding of the source of the magnetic effect and the magnetic modulation of magnetic catalysts is lacking. This perspective focuses on recent advancements in harnessing external magnetic field to improve electrocatalytic water splitting and suggests future directions. First, the mechanism of several magnetic effects and their effects on water splitting are elaborated in detail, including the magnetohydrodynamic effect, magnetothermal effect, spin polarization effect, and magnetoresistance effect. Then, the classification and construction strategies of magnetic effect catalysts are summarized, primarily divided into single metal/alloy catalysts, metal oxide-based catalysts, and other magnetic catalysts. Finally, the challenges and potential perspective of magnetic field-enhanced water splitting are discussed, including mechanism study, in situ characterization, and multi-field synergy effects.
Numerical study on the motion of two parallel spherical particles with different diameters in upward flow
Authors: Sun Xiwang , Lin Zhe , Li Linmin , Zhu Zuchao
Published: September 2024

The settling of particles is related to many industrial processes and research fields. However, due to the complex particle–particle and particle–fluid interactions, the settling mechanism of particles in flowing fluids is not fully understood. This article conducts numerical research on the settling process of two particles with different diameters in parallel in upward flow using the immersion boundary method. The numerical method was validated against experimental results including one particle settling, two parallel particles settling, and two series particles settling. The effects of large particle diameter, upward flow velocity, and initial particle spacing on the settling process were explored. The results indicate that the two particles with same diameter will repel each other when settling in upward flow. Moreover, when the diameters differ, the two particles can experience both attractive and repulsive interactions. The larger the diameter of the large particle, the stronger its attractive influence on the small particle. When the diameter of large particle d2 = 3.0d1, large particle only has an attractive effect on small particle. The wake of each particle forms a distinct velocity boundary with the upward fluid. As the upward flow velocity increases, the interactions between the two particles become increasingly intense. With increasing initial spacing between the particles, their mutual interactions gradually weaken.
Is in-kind kinder than cash? The impact of money vs. food aid on social emotions and aid take-up
Authors: Kassirer Samantha , Jami Ata , Kouchaki Maryam
Published: September 2024

Over the past decade, there has been a shift in the way charities deliver humanitarian aid. Historically, the most prevalent way to help the global poor was by providing in-kind asset transfers. Recently, alternatives to in-kind aid, such as cash aid, have been increasing in prevalence. Although there has been widespread endorsement from the academic community and the public on the popularizing model of giving cash aid, one perspective remains untouched: the recipient’s perspective. Thus, the present research explores how food-insecure individuals feel when receiving money vs. in-kind food aid to help meet their hunger and nutrition needs. Specifically, we explore the degree of positive (e.g., feeling cared for) and negative (e.g., feeling ashamed) social emotions felt when receiving the aid opportunity and how willing recipients are to accept monetary (vs. food) aid. Results from five preregistered experiments (N= 3,110)—a field experiment in Kenya and four online experiments in the United States—find that monetary (vs. food) aid elicits comparatively more of a market-pricing relationship and less of a communal sharing relationship and, hence, makes people feel less positive and more negative social emotions when receiving the help. Subsequently, recipients are less likely to take up monetary (vs. food) aid from a charity. However, we find that this effect does not persist when receiving government aid: Recipients are similarly willing to accept money and in-kind food aid from the government. This research suggests that future scholarship ought to examine ways to improve psychological experiences when receiving money from charity.
Three-dimensional chromatin mapping of sensory neurons reveals that promoter–enhancer looping is required for axonal regeneration
Authors: Palmisano Ilaria , Liu Tong , Gao Wei , Zhou Luming , Merkenschlager Matthias , Mueller Franziska , Chadwick Jessica , Toscano Rivalta Rebecca , Kong Guiping , King James W. D. , Al-jibury Ediem , Yan Yuyang , Carlino Alessandro , Collison Bryce , De Vitis Eleonora , Gongala Sree , De Virgiliis Francesco , Wang Zheng , Di Giovanni Simone
Published: September 2024

The in vivo three-dimensional genomic architecture of adult mature neurons at homeostasis and after medically relevant perturbations such as axonal injury remains elusive. Here, we address this knowledge gap by mapping the three-dimensional chromatin architecture and gene expression program at homeostasis and after sciatic nerve injury in wild-type and cohesin-deficient mouse sensory dorsal root ganglia neurons via combinatorial Hi-C, promoter-capture Hi-C, CUT&Tag for H3K27ac and RNA-seq. We find that genes involved in axonal regeneration form long-range, complex chromatin loops, and that cohesin is required for the full induction of the regenerative transcriptional program. Importantly, loss of cohesin results in disruption of chromatin architecture and severely impaired nerve regeneration. Complex enhancer–promoter loops are also enriched in the human fetal cortical plate, where the axonal growth potential is highest, and are lost in mature adult neurons. Together, these data provide an original three-dimensional chromatin map of adult sensory neurons in vivo and demonstrate a role for cohesin-dependent long-range promoter interactions in nerve regeneration.
Altruism and natural selection in a variable environment
Authors: dos Santos Miguel , Downing Philip A. , Griffin Ashleigh S. , Cornwallis Charlie K. , West Stuart A.
Published: September 2024

Hamilton’s rule provides the cornerstone for our understanding of the evolution of all forms of social behavior, from altruism to spite, across all organisms, from viruses to humans. In contrast to the standard prediction from Hamilton’s rule, recent studies have suggested that altruistic helping can be favored even if it does not benefit relatives, as long as it decreases the environmentally induced variance of their reproductive success (“altruistic bet-hedging”). However, previous predictions both rely on an approximation and focus on variance-reducing helping behaviors. We derived a version of Hamilton’s rule that fully captures environmental variability. This shows that decreasing (or increasing) the variance in the absolute reproductive success of relatives does not have a consistent effect—it can either favor or disfavor the evolution of helping. We then empirically quantified the effect of helping on the variance in reproductive success across 15 species of cooperatively breeding birds. We found that a) helping did not consistently decrease the variance of reproductive success and often increased it, and b) the mean benefits of helping across environments consistently outweighed other variability components of reproductive success. Altogether, our theoretical and empirical results suggest that the effects of helping on the variability components of reproductive success have not played a consistent or strong role in favoring helping.
Single-cell analysis identifies distinct macrophage phenotypes associated with prodisease and proresolving functions in the endometriotic niche
Authors: Henlon Yasmin , Panir Kavita , McIntyre Iona , Hogg Chloe , Dhami Priya , Cuff Antonia O. , Senior Anna , Moolchandani-Adwani Niky , Courtois Elise T. , Horne Andrew W. , Rosser Matthew , Ott Sascha , Greaves Erin
Published: September 2024

Endometriosis negatively impacts the health-related quality of life of 190 million women worldwide. Novel advances in nonhormonal treatments for this debilitating condition are desperately needed. Macrophages play a vital role in the pathophysiology of endometriosis and represent a promising therapeutic target. In the current study, we revealed the full transcriptomic complexity of endometriosis-associated macrophage subpopulations using single-cell analyses in a preclinical mouse model of experimental endometriosis. We have identified two key lesion-resident populations that resemble i) tumor-associated macrophages (characterized by expression of
Folr2
,
Mrc1
,
Gas6,
and
Ccl8+
) that promoted expression of
Col1a1
and
Tgfb1
in human endometrial stromal cells and increased angiogenic meshes in human umbilical vein endothelial cells, and ii) scar-associated macrophages (
Mmp12, Cd9, Spp1, Trem2
+) that exhibited a phenotype associated with fibrosis and matrix remodeling. We also described a population of proresolving large peritoneal macrophages that align with a lipid-associated macrophage phenotype (
Apoe, Saa3, Pid1
) concomitant with altered lipid metabolism and cholesterol efflux. Gain of function experiments using an Apoe mimetic resulted in decreased lesion size and fibrosis, and modification of peritoneal macrophage populations in the preclinical model. Using cross-species analysis of mouse and human single-cell datasets, we determined the concordance of peritoneal and lesion-resident macrophage subpopulations, identifying key similarities and differences in transcriptomic phenotypes. Ultimately, we envisage that these findings will inform the design and use of specific macrophage-targeted therapies and open broad avenues for the treatment of endometriosis.
cGAS activation in classical dendritic cells causes autoimmunity in TREX1-deficient mice
Authors: Li Tong , Yum Seoyun , Wu Junjiao , Li Minghao , Deng Yafang , Sun Lijun , Zuo Xiaoxia , Chen Zhijian J.
Published: September 2024

Detection of cytosolic DNA by the cyclic GMP-AMP (cGAMP) synthase (cGAS)–stimulator of interferon genes (STING) pathway provides immune defense against pathogens and cancer but can also cause autoimmunity when overactivated. The exonuclease three prime repair exonuclease 1 (TREX1) degrades DNA in the cytosol and prevents cGAS activation by self-DNA. Loss-of-function mutations of the TREX1 gene are linked to autoimmune diseases such as Aicardi–Goutières syndrome, and mice deficient in TREX1 develop lethal inflammation in a cGAS-dependent manner. In order to determine the type of cells in which cGAS activation drives autoinflammation, we generated conditional cGAS knockout mice on the Trex1
–/–
background. Here, we show that genetic ablation of the cGAS gene in classical dendritic cells (cDCs), but not in macrophages, was sufficient to rescue Trex1
–/–
mice from all observed disease phenotypes including lethality, T cell activation, tissue inflammation, and production of antinuclear antibodies and interferon-stimulated genes. These results show that cGAS activation in cDC causes autoinflammation in response to self-DNA accumulated in the absence of TREX1.
Securing the future of microbiome research and innovation: the need for biobanking infrastructure in the UK
Authors:   CABI, Ryan Matthew , Bhardwaj Neerupma ,   Eagle Genomics, Camara Miguel ,   University of Nottingham, Dickie John ,   Royal Botanic Gardens, Kew, Finbow Anthony ,   Eagle Genomics, Green David ,   SAMS, Holden Nicola ,   SRUC, Hoptroff Michael ,   Unilever, Johnson Jethro ,   University of Oxford, Law Samantha ,   NCIMB Ltd, Mackenzie-Dodds Jacqueline ,   Natural History Museum, Mauchline Tim ,   Rothamsted Research, Mitchell Alex ,   Eagle Genomics, Morgan Andrew , Murphy Barry ,   Unilever, Peachey Laura ,   University of Bristol, Pedicord Virginia ,   University of Cambridge, Pearson Claire ,   University of Oxford, Roghi Christian ,   Eagle Genomics, Sergaki Chrysi ,   The Medicines and Healthcare Products Regulatory Agency, Shortt Colette ,   FoodObservatory, Sewitz Sven ,   Eagle Genomics, Thomson Craig ,   Harrison Goddard Foote, Walker Alan ,   The Rowett Institute, Aberdeen, Webb Jeremy ,   University of Southampton, Gifford Miriam ,   University of Warwick, Lawley Trevor ,   Microbiotica Ltd, Neville Anne ,   Microbiotica Ltd, Newbold Jamie ,   SRUC, Buddie Alan ,   CABI
Published: September 2024

This report provides an in-depth review of the science and opportunities in microbiome biobanking, inspired by the success of the UK Biobank. It delivers actionable recommendations to establish a world-leading "UK Microbiome Biobank" (UKMB) to support academic and industrial research. The report highlights the importance of microbes in health, agriculture, and the environment, and the need to conserve microbial resources for research and innovation. Key recommendations include establishing the UKMB as a hub-and-spoke model with thematic areas, incorporating existing infrastructure, promoting data and technology exchange, developing standards, and ensuring ethical and regulatory compliance. The UKMB aims to enhance economic competitiveness, support the bioeconomy, and address global challenges.
Atomic scale etching of diamond: insights from molecular dynamics simulations
Authors: Draney Jack S , Vella Joseph R , Panagiotopoulos Athanassios Z , Graves David B
Published: September 2024

Diamond is a promising material for multiple applications in quantum information processing and sensing as well as applications in microelectronics. However, diamond devices can be limited by surface defects that compromise charge stability and spin coherence, among others. Improved strategies in plasma etching of diamond could play an important role in minimizing or eliminating these defects. In this work, we explore plasma-assisted atomic scale etching of diamond using argon ions (Ar+), hydrogen ions (H+) and hydrogen atoms (H). We employ classical molecular dynamics (MD) simulations and test several interatomic potentials based on the Reactive Empirical Bond Order (REBO) form with comparisons to a variety of published experimental results. We performed MD simulations of low-energy hydrogen (

⩽

50 eV) and argon (

⩽

200 eV) ion bombardment of diamond surfaces. Ar+ bombardment can be used to locally smooth initially rough diamond surfaces via the formation of an amorphous C layer, the thickness of which increases with argon ion energy. Subsequent exposure with hydrogen ions (or fast neutrals) will selectively etch this amorphous C layer, leaving the underlying diamond layer mostly intact if the H energy is maintained below about 10 eV. The simulations suggest that combining Ar+ smoothing with selective, near threshold energy H removal of amorphous C can be an effective strategy for diamond surface engineering, leading to more reliable and sensitive diamond color center devices.
Inline estimation of volume fraction in Newtonian emulsions based on ultrasonic velocity profiling viscometry
Authors: Zheng Wenqing , Tasaka Yuji , Ohie Kohei , Murai Yuichi
Published: September 2024

We propose a method for estimating volume fraction of emulsions based on ultrasonic velocity profiling viscometry and validate its feasibility through a series of experiments. The experiments involve emulsions composed of silicone oil as continuous phase and tap water with volume fractions ranging from 10vol% to 30vol%. We introduce the viscosity model for this emulsion to establish the mathematical relationship between volume fraction and viscosity. Subsequently, we calibrate this relationship using ultrasonic spinning rheometry (USR). The identified equation is then applied in estimating the inline volume fraction using ultrasonic velocity profiling combined with pressure drop measurement. The key idea is that by measuring the viscosity in a pipeline the volume fraction is then indirectly estimated employing the identified equation. Through the collection and analysis of experimental data, we confirmed that the USR can capture the characteristics of the emulsion viscosity accurately. Moreover, we found that this method demonstrates applicability and accuracy in measuring volume fractions of emulsions. The results indicate that the mean relative error for this estimation is 24.06% at a volume fraction of 10vol%, and 4.78% at a volume fraction of 30vol%.
MSTAN: multi-scale spatiotemporal attention network with adaptive relationship mining for remaining useful life prediction in complex systems
Authors: Huang Kai , Jia Guozhu , Jiao Zeyu , Luo Tingyu , Wang Qun , Cai Yingjie
Published: September 2024

In the era of smart manufacturing and advanced industrial systems, the high degree of integration and intelligence of equipment demands higher reliability and safety from systems. Existing methods often rely on historical data for Remaining Useful Life (RUL) prediction to achieve Prognostic and Health Management (PHM). However, the internal units of complex equipment exhibit significant spatial correlation and temporal diversity, making PHM for complex equipment a multidimensional challenge involving both temporal and spatial information, thereby severely limits the effectiveness of RUL prediction for complex systems. Addressing these challenges, this study introduces a multi-scale spatiotemporal attention network with adaptive relationship mining, specifically designed for the remaining useful life (RUL) prediction of such equipment. The core of the proposed method lies in the multi-scale feature perception module, which adeptly extracts varied scale features from multidimensional sensor data. Following this, an innovative adaptive relationship mining module is integrated to uncover multi-order coupling relationships between diverse sensors, enhancing the model’s predictive accuracy. Furthermore, a spatiotemporal attention module is employed to discern and emphasize crucial spatiotemporal correlations. To validate the effectiveness and superiority of the proposed method, the Commercial Modular Aero-propulsion System Simulation (C-MAPSS) dataset is employed for comprehensive performance evaluation, the IEEE 2012 PHM bearing dataset is also adopted to demonstrate the generalization and robustness of the proposed method. The results not only show a notable improvement over existing methods but also offer a more intuitive understanding through visual representations, marking a significant stride in enhancing the safety and efficiency of complex systems.
An improved multiple-outlier-robust GNSS/INS EKF filer based on multiple statistical similarity measure
Authors: Han Houzeng , Xu Tao , Li Rongheng , Ma Wenxuan , Wu He
Published: September 2024

High-precision and highly reliable location information is the key support for autonomous driving applications. Global Navigation satellite system (GNSS)/Inertial navigation system (INS) integrated positioning is a typical high-precision positioning technology. However, satellite signals are easily affected by various interferences such as signal blocking and multipath problems, leading to performance degradation in complex urban environments. The traditional extended Kalman filtering (EKF) cannot handle observation outlier, and the system’s positioning accuracy sharply declines when the observations are affected by non-Gaussian heavy-tailed noise. Therefore, this paper presents an improved multiple-outlier-robust extended Kalman filter (I-MOREKF) for GNSS/INS Loosely Coupled Integration. A multiple statistical similarity measure (MSSM) is built to evaluate the similarity between two random vectors from dimension to dimension. Then, the I-MOREKF is proposed by maximizing a cost function based on the MSSM, and considering the robust estimation with IGG III model. The proposed model effectively removes multiple types of errors in complex environments. A vehicular test was carried out to validate the feasibility and performance of the proposed model. Simulated random gross errors are introduced in GNSS measurements, and the measurement noises are corrupted by heavy-tail noise. The results show that simulated gross errors can be successfully detected with I-MOREKF model, and the 3D position Root Meas Square Error is 0.0148 m for I-MOREKF, which are improved by 97.2%,13.5% and 52.9%, as compared with EKF, IGG Ⅲ and MOREKF.
Simultaneous local normal forms of dynamical systems with singular underlying geometric structures
Authors: Jiang Kai , Ratiu Tudor S , Tien Zung Nguyen
Published: September 2024

The aim of this paper is to develop, for the first time, a general theory of simultaneous local normalisation of couples

(
X
,

G

)

, where X is a dynamical system (vector field) and

G

is an underlying geometric structure preserved by X, even if both have singularities. Such couples appear naturally in many problems, e.g. Hamiltonian dynamics, where

G

is a symplectic structure and one has the theory of Birkhoff normal forms, or constrained dynamics, where

G

is a smooth, in general singular, distribution of tangent subspaces, etc. In this paper, the geometric structure

G

is of the following types: volume form, symplectic form, contact form, Poisson tensor, as well as their singular versions. The paper addresses mainly the more difficult situations when both X and

G

are singular at a point and its results prove the existence of natural simultaneous normal forms in these cases. In general, the normalisation is only formal, but when

G

and X are (real or complex) analytic and X is analytically or Darboux integrable, then the simultaneous normalisation is also analytic. Our theory is based on a new approach, called the Toric Conservation Principle, as well as the classical step-by-step normalisation technique, and the equivariant path method.
How to quantify sleepiness during an attempt to sleep?
Authors: Putilov Arcady A , Sveshnikov Dmitry S , Yakunina Elena B , Mankaeva Olga V , Puchkova Alexandra N , Shumov Dmitry E , Gandina Eugenia O , Taranov Anton O , Ligun Natalya V , Donskaya Olga G , Verevkin Evgeniy G , Dorokhov Vladimir B
Published: September 2024

Background. Sleepiness assessment tools were mostly developed for detection of an elevated sleepiness level in the condition of sleep deprivation and several medical conditions. However, sleepiness occurs in various other conditions including the transition from wakefulness to sleep during an everyday attempt to get sleep. Objective. We examined whether objective sleepiness indexes can be implicated in detection of fluctuations in sleepiness level during the polysomnographically-monitored attempt to sleep, i.e. in the absence of self-reports on perceived sleepiness level throughout such an attempt. Approach. The polysomnographic signals were recorded in the afternoon throughout 106 90 min napping attempts of 53 university students (28 females). To calculate two objective sleepiness indexes, the electroencephalographic (EEG) spectra were averaged on 30 s epochs of each record, assigned to one of 5 sleep–wake stages, and scored using either the frequency weighting curve for sleepiness substate of wake state or loadings of each frequency on the 2nd principal component of variation in the EEG spectrum (either sleepiness score or PC2 score, respectively). Main results. We showed that statistically significant fluctuations in these two objective sleepiness indexes during epochs assigned to wake stage can be described in terms of the changes in verbally anchored levels of subjective sleepiness assessed by scoring on the 9-step Karolinska Sleepiness Scale. Significance. The results afford new opportunities to elaborate importance of intermediate substates between wake and sleep states for sleep–wake dynamics in healthy individuals and patients with disturbed sleep.
Higher-order topological phase with subsystem symmetries
Authors: You Yizhi
Published: September 2024

A wide variety of higher-order symmetry-protected topological phases (HOSPT) with gapless corners or hinges have been proposed as descendants of topological crystalline insulators protected by spatial symmetry. In this work, we address a new class of higher-order topological states that do not require crystalline symmetries but instead rely on subsystem symmetry for protection. We propose several strongly interacting models with gapless hinges or corners based on a decorated hinge-wall condensate picture. The hinge-wall, which appears as the defect configuration of a Z
2 paramagnet, is decorated with a lower-dimensional SPT state. Such a unique hinge-wall decoration structure leads to gapped surfaces separated by gapless hinges. The non-trivial nature of the hinge modes can be captured by a

1
+
1

D conformal field theory with a Wess–Zumino–Witten term. Moreover, we establish a no-go theorem to demonstrate the ungappable nature of the hinges by making a connection between the generalized Lieb–Schultz–Mattis theorem and the boundary anomaly of the HOSPT state. This universal correspondence engenders a comprehensive criterion to determine the existence of HOSPT under certain symmetries, regardless of the microscopic Hamiltonian.