bluuebunny/crossref_metadata_2025 huggingface dataset:
Wake interaction between two spar-type floating offshore wind turbines under different layouts
Authors: Huang Yang , Zhao Weiwen , Wan Decheng
Published: September 2023

Limited by layout space and manufacturing costs, wake interaction in offshore wind farms is inevitable and can have adverse effects on the performance of downstream wind turbines. To gain a better understanding of the wake interaction between Floating Offshore Wind Turbines (FOWTs), this paper conducts coupled aero-hydrodynamic simulations for two spar-type FOWTs under different layouts. The Unsteady Actuator Line Model (UALM) is used to analyze the unsteady aerodynamic loads of the wind turbine, while the hydrodynamic responses of the floating support platform are obtained using the Computational Fluid Dynamics (CFD) method. To predict the aero-hydrodynamic performance of the FOWT under combined wind and waves, an in-house CFD code developed at Shanghai Jiao Tong University (SJTU), called FOWT-UALM-SJTU solver, is utilized. First, grid convergence test and time step sensitivity study are performed to determine appropriate simulation parameters. Subsequently, numerical simulations of two FOWTs under tandem and offset layouts are conducted to investigate the influence of wake interaction on the performance of downstream FOWT. The dynamic responses of the FWOT, including aerodynamic loads, platform motions, and wake characteristics, are analyzed in detail. From the simulation results and discussions, several conclusions are drawn. Both platform motions and wake interaction contribute to an increased variation range of inflow wind speed experienced by the downstream FOWT, thereby exacerbating the instability of its aerodynamic loads. Under the tandem layout, the platform motions of the upstream FOWT and the downstream FOWT exhibit opposite effects on the aerodynamic loads of the downstream FOWT. Moreover, platform motions increase turbulence intensity in the wake region, accelerating wake velocity recovery and widening the wake width.
Pore-scale study of miscible density instability with viscosity contrast in porous media
Authors: Chen Jin , Wang Geng , Yang Junyu , Lei Timan , Luo Kai H.
Published: September 2023

The transport of miscible fluids in porous media is a prevalent phenomenon that occurs in various natural and industrial contexts. However, this fundamental phenomenon is usually coupled with interface instabilities (e.g., viscous/density fingering), which has yet to be thoroughly investigated. In this paper, a multiple-relaxation-time lattice Boltzmann method is applied to study the displacement between two miscible fluids in porous media at the pore scale, with the coexistence of density difference (Rayleigh number Ra), viscosity contrast (R), and injection velocity (Utop). A parametric study is conducted to evaluate the impact of Ra, R, and Utop on the flow stability. For a fixed Ra that can trigger density fingering, the increase in R or Utop is found to suppress density fingering. Consequently, under a large Utop and a moderate R, the density fingering is fully stabilized and the flow follows a stabile pattern. Furthermore, as both R and Utop grow to a sufficiently high level, they can jointly trigger viscous fingering. In addition, the increasing Ra shows an enhancing effect on both density fingering and viscous fingering. Finally, by quantitatively analyzing the fingering length (lm) and the fingering propagation time (te), five different flow patterns are classified as viscosity-suppressed (I), viscosity-enhanced (II), viscosity-unstable (III), displacement-suppressed (IV), and stable (V) regimes. In a three-dimensional parameter space spanned by Ra, R, and Utop, the parameter ranges of the five regimes are determined according to lm and te. These findings hold a significant value in providing guidance for controlling the flow stability by selecting appropriate operating conditions.
Active flutter suppression on a flexible wing via leading-edge blowing and circulation control
Authors: Chen Zhen , Shi Zhiwei , Chen Sinuo , Liao Xueqi , Mei Yang
Published: September 2023

Flutter is a classical aeroelastic phenomenon that seriously affects the performance of flexible wings. This study investigates flutter suppression through flow control for a flexible wing. Aerodynamic force, flow field, and dynamic aeroelastic response measurements are conducted to analyze the mechanism of flutter suppression through flow control on a flexible wing modified to include leading-edge blowing (LEB) and circulation control (CC) actuators around the wing tip. Furthermore, the flutter control effects of two control strategies, i.e., steady state control and proportion–integral–differential (PID) control, are compared. The results show that steady LEB and steady CC can effectively reduce the flutter amplitude and increase the critical flutter velocity. When the mass flow coefficient CQ≥1.46×10−3, the Coanda jet has better flutter suppression effect than the leading-edge jet. Moreover, a closed-loop CC control based on the PID algorithm demonstrates that PID control can effectively improve the flutter control efficiency. Compared to steady flow control, PID control increases the critical velocity by more than 52.60% and reduces the air consumption by 90.44%.
Occupancies of tetra- and octahedral sites in CoFe2O4 nanoparticles: The effect of the sintering temperature
Authors: Bilovol Vitaliy , Sikora Marcin , Lisníková Soňa , Żukrowski Jan , Berent Katarzyna , Gajewska Marta
Published: September 2023

A temperature factor is one of the main parameters in the synthesis of nanoparticles and can affect considerably the arrangement of atoms in the lattice. In the system of magnetically hard CoFe2O4 spinel ferrite, the distribution of cations directly determines the magnetic properties of the sample. It was studied, on products of co-precipitation synthesis followed by a temperature dependent sinterization, by x-ray diffraction (XRD), x-ray absorption (XAS) using synchrotron radiation, vibrating sample magnetometry, and 57Fe Mössbauer spectroscopy (MS). From the Rietveld refinement of XRD patterns, the site occupancies reveal the following trend: with a decrease in the sintering temperature, the inversion degree parameter γ, which is a fraction of Co ions residing in the octahedral sites, decreases. For the highest sintering temperature explored in this work, 1000 °C, γ ≈ 0.83 giving rise to (Co0.17Fe0.83)A[Co0.83Fe1.27]BO4 formulation. For the lowest sintering temperature explored, 500 °C, the inversion degree is approximately 0.69 giving rise to (Co0.31Fe0.69)A[Co0.69Fe1.31]BO4 formulation. The propensity for the cationic arrangement was also confirmed by MS. Qualitative analysis of XAS at Co L3,2 edges strongly supports the tendency observed by XRD: the lower the sintering temperature, the more Co ions tend to occupy the tetrahedral sites. The magnetic behavior of the samples is consistent with the particle size which was determined by transmission/scanning electron microscopies. The particle size is the product of different sintering temperatures after the primary synthesis.
Acoustic chiral mode switching by dynamic encircling of exceptional points
Authors: Duan Youdong , Geng Linlin , Guo Qiuquan , Yang Jun , Hu Gengkai , Zhou Xiaoming
Published: September 2023

Chiral mode switching initiated by dynamic encircling of an exceptional point (EP) has shown an extraordinary ability in wave controlling. In this work, we study the chiral mode transfer for acoustic waves in the coupled waveguide system that supports the non-adiabatic evolution of eigenstates. The system comprises a finite number of structural elements, which are constructed according to parametric conditions in the loop enclosing the EP and then stacked such that acoustic propagation in the waveguide system is equivalent to the dynamic encircling of the EP. An analytic model based on the spatial coupled-mode theory is developed, which provides a practical guide to design the system and makes predictions for dynamic evolution. Numerical simulation of the waveguide system is conducted to demonstrate the chiral mode switching for sounds.
Understanding epitaxy of graphene: From experimental observation to density functional theory and machine learning
Authors: Zheng Ming-Sheng , Zhou Shaojie , Wang Xinmo , Gao Lei
Published: September 2023

Due to enormous applications of large-area graphene with high quality, the epitaxial growth strategies have drawn a plethora of attention. However, the bottleneck in the production of graphene has caused delayed development in recent years, which is owing to the poor understanding of interaction mechanisms between graphene and the underlying metallic and non-metallic substrate. To understand the thermodynamics of graphene–substrate interface and growth kinetics, accurate density functional theory (DFT) calculations have been proved as an effective way, in terms of cost and time, compared with traditional experimental methods, which can calculate the interaction between graphene and substrates, helping us to better understand the practical phenomena. Here, we show the use of DFT methods to evaluate both van der Waals interaction and covalent bonding. Many of computational results fit well with the experimental observations. To address the relative low accuracy and small computation capacity (number of atoms) of common DFT models, we suggest that the machine learning (ML) methods will be a fresh impetus for epitaxial growth strategy of graphene, which put forward effective interpretations for complicated interconnections and correlations among the properties, thereby enabling ML a promising strategy for understanding, design, and synthesis of graphene over other 2D materials.
Tuning magnetic properties of polar magnets (Mn1−xCox)2Mo3O8 (0 ≤ x ≤ 1) with interacted magnetic sublattices
Authors: Chang Yuting , You Bin , Xie Yunlong , Liu Yong , Xiong Rui , Lu Chengliang , Liu Jun-Ming
Published: September 2023

Single crystalline polar magnets (Mn1−xCox)2Mo3O8 (0 ≤ x ≤ 1) have been synthesized, and their magnetic properties have been studied. Magnetic interactions of the samples can be modulated drastically by Co-doping, and a ferrimagnetic to antiferromagnetic phase transition is identified at x = 0.35. For the samples hosting a ferrimagnetic state (0 ≤ x ≤ 0.3), square-like magnetic hysteresis loops are commonly identified, and the remnant magnetization and coercive field are revealed to strongly depend on the Co-content and temperature. The occupation ratio and magnetic nature of Co2+ are key ingredients to dictate the competition of various magnetic exchange couplings in the samples.
Dynamics of wire frame glasses in two dimensions
Authors: King David A.
Published: September 2023

The dynamics of wire frame particles in concentrated suspension are studied by means of a 2D model and compared to those of rod-like particles. The wire frames have bent or branched structures constructed from infinitely thin, rigid rods. In the model, a particle is surrounded by diffusing points that it cannot cross. We derive a formal expression for the mean squared displacement (MSD) and, by using a self-consistent approximation, we find markedly different dynamics for wire frames and rods. For wire frames, there exists a critical concentration of points above which they become frozen with the long time MSD reaching a plateau. Rods, on the other hand, always diffuse by reptation. We also study the rheology through the elastic stress, and more striking differences are found: the initial magnitude of the stress for wire frames is much larger than for rods, scaling such as the square of the point concentration, and above the critical concentration, the stress for wire frames appears to persist indefinitely while for rods it always decays.
Fe-FeNn nanoparticles anchored bamboo-like morphology of N-doped graphitic carbon nitride nanotubes enabled electrochemical DNA-based biosensing of head and neck-squamous cell carcinoma miRNA-203
Authors: Kannan Palanisamy , Wang Peng , Lei Lu , Wang Hui , Subramaniam Saravanan , Ji Shan
Published: September 2023

We describe a biosensing platform for the early screening of metastatic lymph nodes in patients with head and neck squamous-cell-carcinoma. The tunable iron nanoparticles (Fe-FeNn) inserted bamboo-like nanostructured N-doped carbon nanotubes (CNTs) obtained from a graphitic carbon nitride (GCN) are a source material for the highly sensitive detection of miRNA-203 in human serum and urine samples. The CNTs/GCN with tunable Fe precursors annealed at 900 °C enables the formation of Fe-FeNn nanoparticles (n = 0.5, 1.0, and 2.0 mmol of Fe) intercalated bamboo-like morphology of CNTs/GCN, which is denoted as Fe-FeNn/CNTs/GCN nanocomposite. Particularly, the bamboo-like nanotubes were derived from layered-structure of graphitic carbons with several voids and pores. The synthesized bamboo-like Fe-FeNn/CNTs/GCN was used to construct a biosensing platform through coordinate covalent bonding between Fe-FeNn and phosphate functionality of probe DNA. The developed bamboo-like Fe-FeNn/CNTs/GCN-based biosensing platform exhibited potential detection toward cancerous miRNA from 10 to 5000 fM with the limit of detection of 0.11 fM (S/N = 3). Under optimized conditions, the developed Fe-FeNn/CNTs/GCN biosensing platform was applied to detect miRNA in complexed biological fluids, such as human blood serum and saliva samples with satisfied recovery results (94.22%–97.40%).
Superelastic-like nonlinear deformation hidden in ferroelectric ceramics
Authors: Minami Susumu , Nakayama Tomohiro , Shimada Takahiro
Published: September 2023

The mechanical response of ferroelectric (piezoelectric) ceramics under high stress conditions has a crucial role from the perspective of engineering applications such as advanced actuator systems. In this study, we perform first-principles calculations to clarify the deformation behavior and (ideal) tensile strength for typical ferroelectric ceramics of PbTiO3 (PTO) under high mechanical loading. We find the superelastic-like nonlinear deformation behavior in ferroelectric PTO. In addition, it has several inflection points and shows a large critical strain compared to the paraelectric phase. We conclude that the unique nonlinear deformation in PTO originates from attributable to the displacement of oxygen atoms due to the ferroelectric phase transition based on analyzing the interatomic distances of each atom and an integrated crystal orbital Hamiltonian population with respect to strain. Furthermore, we also calculate the piezoelectric coefficient for PTO and reveal that it shows the singular peak at inflection points of the stress–strain curve. Unveiling and engineering the hidden superelastic-like deformation in the ferroelectric phase may open promising paradigms for functional piezoelectric devices.
Nonlinear constitutive calculation method of rarefied flow based on deep convolution neural networks
Authors: Yao Shaobo , Zhao Wenwen , Wu Changju , Chen Weifang
Published: September 2023

In the field of rarefied gas dynamics, the presence of non-equilibrium flow characteristics poses significant challenges for achieving efficient and accurate numerical simulation methods. These challenges arise from the complex coexistence of these phenomena at multiple scales. The recent advent of intelligent fluid mechanics has introduced the data-driven nonlinear constitutive relation (DNCR) method as a promising approach for expeditious physical modeling of non-equilibrium rarefied flows. To enhance the generalization capabilities of the DNCR method, this study proposes a deep convolutional neural network model (DNCR-CNN) based on data-driven nonlinear constitutive relations, integrated with free-form deformation (FFD). Employing FFD technology, a series of hypersonic geometric shapes are generated for model training, and a multi-task learning-based deep convolutional neural network model is subsequently trained. The prediction of the hypersonic geometric shapes test set is carried out, and the results of the model prediction are substituted in the conservation equation for the iterative solution, thereby enhancing the DNCR method's generalization performance for varying geometric shapes. Upon conducting a comparative analysis of the outcomes obtained from DNCR, Navier–Stokes (NS), and unified gas kinetic scheme (UGKS), it is revealed that the DNCR method can maintain computational resource levels equivalent to those of the NS equation while achieving a level of accuracy comparable to UGKS under diverse geometric shapes and grid resolutions. The enhancements in usability render the DNCR method a potent tool for addressing the challenges posed by rarefied gas, thereby expanding its applicability within the field.
Comparative study of surface roughness models in the hydro-thermal characterization of flow over rough walls
Authors: Samal Sangram Kumar , Kumar Pratyush , Saha Sandip K.
Published: September 2023

Surface roughness is responsible for the localized turbulence, which disrupts the viscous sublayer, affecting pressure drop and heat transfer. Thus, the numerical modeling of the effect of roughness on the fluid flow and heat transfer is quite essential. In this work, a numerical model is developed in OpenFOAM to incorporate the effect of surface roughness by modifying the wall function. Its accuracy is validated with available semi-empirical correlations and experimental results. The efficacy of available models for evaluating equivalent sand–grain roughness height (ks) based on surface statistics is investigated. A correlation for the dimensionless near-wall cell center distance (y+) is developed as the function of the Reynolds number and the equivalent sand–grain roughness height. The developed numerical model is validated with the semi-empirical relation and experimental results from the literature with average deviations of 7%. It is found that the equivalent sand–grain roughness height, evaluated using expressions reported by Flack et al. [ “Skin friction measurements of systematically-varied roughness: Probing the role of roughness amplitude and skewness,” Flow Turbul. Combust. 104, 317–329 (2020)], shows the lowest average deviation of 3.48% with the experimental data among all the considered formulas of ks. The proposed correlation of y+ well predicts the minimum dimensionless near-wall distance that gives near-wall spacing independent result with a mean absolute deviation of 2.1% compared to that obtained from the numerical results. The correlation of y+ developed based on the fluid flow analysis is further used to predict the Stanton number, which reasonably agrees with the experimental results.
Inverted organic tandem solar cells with a charge recombination stack employing spatially confined p-type electrical doping
Authors: Chang Yi-Chien , Larrain Felipe A. , Fuentes-Hernandez Canek , Park Youngrak , Kippelen Bernard
Published: September 2023

We report on the application of solution-based p-type electrical doping using 12-molybdophosphoric acid hydrate (PMA) to the fabrication of organic tandem solar cells. Such a doping approach leads to a spatially confined vertical doping profile down to a limited depth from the surface of polymer films, thus allowing the hole-collecting component of the charge recombination stack to be embedded in the photoactive layer of the bottom sub-cell. This simplifies the device architecture by removing the need for an extra dedicated hole-collecting layer. It is shown that this novel charge recombination stack comprising a PMA-doped bottom photoactive layer and a trilayer of Ag/AZO/PEIE is compatible with a solution-processed top photoactive layer. The fabricated inverted organic tandem solar cells exhibit an open-circuit voltage that is close to the sum of the open-circuit voltages of the individual sub-cells, and a fill factor that is close to the better fill factor of the two sub-cells.
Influences of size, shape, and wall thickness on melting entropy and enthalpy of metallic nanostructures
Authors: Zhu Min , Liu Jin , Yang Xuexian
Published: September 2023

From the perspective of a bond-order-length-strength correlation, we put forward an analytical solution to describe the size, shape, and wall thickness dependency of melting temperature, entropy, and enthalpy for metallic nanostructures. Theoretical reproduction of measurements clarified that (i) when the crystal size reduces, the atomic coordination number lowers, the atomic cohesive energy decreases, and the surface-to-volume ratio increases; (ii) at the same equivalent radius, with the decrease in the number of sides for polyhedral nanoparticles and polygonal nanowires or nanotubes, the melting temperature, entropy, and enthalpy depress; and (iii) the melting temperature, entropy, and enthalpy of nanotubes are always lower than those of nanowires with the same cross-sectional radius. The present formulation is accurate and convenient, which not only shows deeper insight into the physical origins of a melting thermodynamic property response to perturbations but also provides guidance for the design and optimization of electronic nanodevices.
Discovery of the Baijifeng impact structure in Tonghua, Jilin, China
Authors: Chen Ming , Lu Yang , Ning Jiahao , Yang Wenge , Shu Jinfu , Mao Ho-kwang
Published: September 2023

An impact structure 1400 m in diameter, formed by a bolide impact, has been discovered on Baijifeng Mountain in Tonghua City in Northeast China’s Jilin province. The impact structure takes the form of a cirque-shaped depression on the top of the mountain and is located in a basement mainly composed of Proterozoic sandstone and Jurassic granite. A large number of rock fragments composed mainly of sandstone, with a small amount of granite, are distributed on the top of Baijifeng Mountain. Planar deformation features (PDFs) have been found in quartz in the rock and mineral clasts collected from the surface inside the depression. The forms of the PDFs indexed in the quartz include among others, {101̄3}, {101̄2}, and {101̄1}. The presence of these PDFs provides diagnostic evidence for shock metamorphism and the impact origin of the structure. The impact event took place after the Jurassic Period and probably much later.
The discovery of tomato spotted wilt virus
Authors: Geering Andrew D. W.
Published: September 2023

The discovery of tomato spotted wilt virus (TSWV) was an important finding in Australian science, involving a self-educated field naturalist and a small team of plant pathologists who had to work in relative academic isolation and with inadequate glasshouse facilities. After its discovery in Melbourne in 1915, TSWV rapidly spread throughout Australia and by 1929, it posed an existential threat to the tomato industry. To address this problem, a joint project between the Waite Agricultural Research Institute and the Council for Scientific and Industrial Research was initiated in 1926. This collaboration, led by University of Adelaide plant pathologist Geoffrey Samuel, was initially turbulent but ultimately highly productive. Within an eight-year period, significant advances were made in understanding the aetiology of the disease, particularly by establishing that it was caused by a thrips-transmitted virus. Aspects of the epidemiology and control of the virus were also elucidated such as investigating alternative hosts of the virus. This research was made possible through substantial improvements in mechanical inoculation techniques.
Eucalyptus cryptica (Myrtaceae): a critically endangered new species
Authors: Wilson Trevor C. , Rutherford Susan , Yap Jia-Yee S. , Douglas Steven M. , Lee Enhua , Rossetto Maurizio
Published: September 2023

Recognition that the critically endangered mallee Eucalyptus sp. Cattai (Gregson s.n. 28 Aug 1954) is a distinct species has been complicated by close morphological similarity between it and other members of E. subgenus Symphyomyrtus section Latoangulatae series Annulares. Recent genomic evidence has demonstrated that it is distinct from other species. In this study, we provide E. sp. Cattai with the new species name, E. cryptica T.C.Wilson, S.Rutherf. & S.M.Douglas, and use genomic scans of adults and seedlings to assist in its description and support its conservation by identifying hybrids. Accompanying the description of E. cryptica are images, diagnostic illustrations and an updated part of the Eucalyptus key for the Flora of New South Wales.
Parallel molecular computation on digital data stored in DNA
Authors: Wang Boya , Wang Siyuan Stella , Chalk Cameron , Ellington Andrew D. , Soloveichik David
Published: September 2023

DNA is an incredibly dense storage medium for digital data. However, computing on the stored information is expensive and slow, requiring rounds of sequencing, in silico computation, and DNA synthesis. Prior work on accessing and modifying data using DNA hybridization or enzymatic reactions had limited computation capabilities. Inspired by the computational power of “DNA strand displacement,” we augment DNA storage with “in-memory” molecular computation using strand displacement reactions to algorithmically modify data in a parallel manner. We show programs for binary counting and Turing universal cellular automaton Rule 110, the latter of which is, in principle, capable of implementing any computer algorithm. Information is stored in the nicks of DNA, and a secondary sequence-level encoding allows high-throughput sequencing-based readout. We conducted multiple rounds of computation on 4-bit data registers, as well as random access of data (selective access and erasure). We demonstrate that large strand displacement cascades with 244 distinct strand exchanges (sequential and in parallel) can use naturally occurring DNA sequence from M13 bacteriophage without stringent sequence design, which has the potential to improve the scale of computation and decrease cost. Our work merges DNA storage and DNA computing, setting the foundation of entirely molecular algorithms for parallel manipulation of digital information preserved in DNA.
A step toward precision gerontology: Lifespan effects of calorie and protein restriction are consistent with predicted impacts on entropy generation
Authors: Semerciöz-Oduncuoğlu Ayşe Selcen , Mitchell Sharon E. , Özilgen Mustafa , Yilmaz Bayram , Speakman John R.
Published: September 2023

Understanding aging is a key biological goal. Precision gerontology aims to predict how long individuals will live under different treatment scenarios. Calorie and protein restriction (CR and PR) extend lifespan in many species. Using data from C57BL/6 male mice under graded CR or PR, we introduce a computational thermodynamic model for entropy generation, which predicted the impact of the manipulations on lifespan. Daily entropy generation decreased significantly with increasing CR level, but not PR. Our predictions indicated the lifespan of CR mice should increase by 13 to 56% with 10 to 40% CR, relative to ad libitum-fed animals. This prediction was broadly consistent with the empirical observation of the lifespan impacts of CR in rodents. Modeling entropy fluxes may be a future strategy to identify antiaging interventions.
Diversified farms bolster forest-bird populations despite ongoing declines in tropical forests
Authors: Hendershot J. Nicholas , Echeverri Alejandra , Frishkoff Luke O. , Zook James R. , Fukami Tadashi , Daily Gretchen C.
Published: September 2023

While some agricultural landscapes can support wildlife in the short term, it is uncertain how well they can truly sustain wildlife populations. To compare population trends in different production systems, we sampled birds along 48 transects in mature forests, diversified farms, and intensive farms across Costa Rica from 2000 to 2017. To assess how land use influenced population trends in the 349 resident and 80 migratory species with sufficient data, we developed population models. We found, first, that 23% of species were stable in all three land use types, with the rest almost evenly split between increasing and decreasing populations. Second, in forest habitats, a slightly higher fraction was declining: 62% of the 164 species undergoing long-term population changes; nearly half of these declines occurred in forest-affiliated invertivores. Third, in diversified farms, 49% of the 230 species with population changes were declining, with 60% of these declines occurring in agriculture-affiliated species. In contrast, 51% of the species with population changes on diversified farms showed increases, primarily in forest-affiliated invertivores and frugivores. In intensive farms, 153 species showed population changes, also with similar proportions of species increasing (50%) and decreasing (50%). Declines were concentrated in agriculture-affiliated invertivores and forest-affiliated frugivores; increases occurred in many large, omnivorous species. Our findings paint a complex picture but clearly indicate that diversified farming helps sustain populations of diverse, forest-affiliated species. Despite not fully offsetting losses in forest habitats, diversified farming practices help sustain wildlife in a critical time, before possible transformation to nature-positive policies and practices.
Mechanical Fourier transform for programmable metamaterials
Authors: Lin Xin , Pan Fei , Ma Yong , Wei Yuling , Yang Kang , Wu Zihong , Guan Juan , Ding Bin , Liu Bin , Xiang Jinwu , Chen Yuli
Published: September 2023

Proactively programming materials toward target nonlinear mechanical behaviors is crucial to realize customizable functions for advanced devices and systems, which arouses persistent explorations for rapid and efficient inverse design strategies. Herein, we propose a “mechanical Fourier transform” strategy to program mechanical behaviors of materials by mimicking the concept of Fourier transform. In this strategy, an arbitrary target force–displacement curve is decomposed into multiple cosine curves and a constant curve, each of which is realized by a rationally designed multistable module in an array-structured metamaterial. Various target curves with distinct shapes can be rapidly programmed and reprogrammed through only amplitude modulation on the modules. Two exemplary metamaterials are demonstrated to validate the strategy with a macroscale prototype based on magnet lattice and a microscale prototype based on an etched silicon wafer. This strategy applies to a variety of scales, constituents, and structures, and paves a way for the property programming of materials.
Cryo-EM structure determination of small therapeutic protein targets at 3 Å-resolution using a rigid imaging scaffold
Authors: Castells-Graells Roger , Meador Kyle , Arbing Mark A. , Sawaya Michael R. , Gee Morgan , Cascio Duilio , Gleave Emma , Debreczeni Judit É. , Breed Jason , Leopold Karoline , Patel Ankoor , Jahagirdar Dushyant , Lyons Bronwyn , Subramaniam Sriram , Phillips Chris , Yeates Todd O.
Published: September 2023

Cryoelectron microscopy (Cryo-EM) has enabled structural determination of proteins larger than about 50 kDa, including many intractable by any other method, but it has largely failed for smaller proteins. Here, we obtain structures of small proteins by binding them to a rigid molecular scaffold based on a designed protein cage, revealing atomic details at resolutions reaching 2.9 Å. We apply this system to the key cancer signaling protein KRAS (19 kDa in size), obtaining four structures of oncogenic mutational variants by cryo-EM. Importantly, a structure for the key G12C mutant bound to an inhibitor drug (AMG510) reveals significant conformational differences compared to prior data in the crystalline state. The findings highlight the promise of cryo-EM scaffolds for advancing the design of drug molecules against small therapeutic protein targets in cancer and other human diseases.
Dead-zone-compensated design as general method of flow field optimization for redox flow batteries
Authors: Pan Lyuming , Sun Jing , Qi Honghao , Han Meisheng , Dai Qiuxia , Xu Junhui , Yao Shengxin , Li Quanlong , Wei Lei , Zhao Tianshou
Published: September 2023

One essential element of redox flow batteries (RFBs) is the flow field. Certain dead zones that cause local overpotentials and side effects are present in all conventional designs. To lessen the detrimental effects, a dead-zone-compensated design of flow field optimization is proposed. The proposed architecture allows for the detection of dead zones and their compensation on existing flow fields. Higher reactant concentrations and uniformity factors can be revealed in the 3D multiphysical simulation. The experiments also demonstrate that at an energy efficiency (EE) of 80%, the maximum current density of the novel flow field is 205 mA cm
−2
, which is much higher than the values for the previous ones (165 mA cm
−2
) and typical serpentine flow field (153 mA cm
−2
). Extensions of the design have successfully increased system EE (2.7 to 4.3%) for a variety of flow patterns. As a result, the proposed design is demonstrated to be a general method to support the functionality and application of RFBs.
Environmental DNA reveals the genetic diversity and population structure of an invasive species in the Laurentian Great Lakes
Authors: Andres Kara J. , Lodge David M. , Andrés Jose
Published: September 2023

Environmental DNA (eDNA) has been established as a noninvasive and efficient approach to sample genetic material from aquatic environments. Although most commonly used to determine species presence and measure biodiversity, eDNA approaches also hold great potential to obtain population-level genetic information from water samples. In this study, we sequenced a panel of multiallelic microsatellite markers from filtered water and fish tissue samples to uncover patterns of intraspecific diversity in the freshwater Round Goby (Neogobius melanostomus) across their invaded range in the Laurentian Great Lakes region. Although we found that the concentration of nuclear eDNA is lower than mitochondrial eDNA, we nonetheless detected over two-thirds of all nuclear alleles identified from genotyped tissues in our eDNA samples, with the greatest recovery of common alleles in the population. Estimates of allele frequencies and genetic variability within and between populations were detected from eDNA in patterns that were consistent with individual tissue-based estimates of genetic diversity and differentiation. The strongest genetic differentiation in both eDNA and tissues exists in an isolation by distance pattern. Our study demonstrates the potential for eDNA-based approaches to characterize key population parameters required to effectively monitor, manage, or sustain aquatic species.
Hey2
enhancer activity defines unipotent progenitors for left ventricular cardiomyocytes in juxta-cardiac field of early mouse embryo
Authors: Watanabe Yusuke , Wang Yunce , Tanaka Yuki , Iwase Akiyasu , Kawamura Teruhisa , Saga Yumiko , Yashiro Kenta , Kurihara Hiroki , Nakagawa Osamu
Published: September 2023

The cardiac crescent is the first structure of the heart and contains progenitor cells of the first heart field, which primarily differentiate into left ventricular cardiomyocytes. The interface between the forming cardiac crescent and extraembryonic tissue is known as the juxta-cardiac field (JCF), and progenitor cells in this heart field contribute to the myocardium of the left ventricle and atrioventricular canal as well as the epicardium. However, it is unclear whether there are progenitor cells that differentiate specifically into left ventricular cardiomyocytes. We have previously demonstrated that an enhancer of the gene encoding the Hey2 bHLH transcriptional repressor is activated in the ventricular myocardium during mouse embryonic development. In this study, we aimed to investigate the characteristics of cardiomyocyte progenitor cells and their cell lineages by analyzing
Hey2
enhancer activity at the earliest stages of heart formation. We found that the
Hey2
enhancer initiated its activity prior to cardiomyocyte differentiation within the JCF.
Hey2
enhancer-active cells were present rostrally to the
Tbx5
-expressing region at the early phase of cardiac crescent formation and differentiated exclusively into left ventricular cardiomyocytes in a lineage distinct from the
Tbx5
-positive lineage. By the late phase of cardiac crescent formation,
Hey2
enhancer activity became significantly overlapped with
Tbx5
expression in cells that contribute to the left ventricular myocardium. Our study reveals that a population of unipotent progenitor cells for left ventricular cardiomyocytes emerge in the JCF, providing further insight into the mode of cell type diversification during early cardiac development.
Dynamic switching of neural oscillations in the prefrontal–amygdala circuit for naturalistic freeze-or-flight
Authors: Han Hio-Been , Shin Hee-Sup , Jeong Yong , Kim Jisoo , Choi Jee Hyun
Published: September 2023

The medial prefrontal cortex (mPFC) and basolateral amygdala (BLA) are involved in the regulation of defensive behavior under threat, but their engagement in flexible behavior shifts remains unclear. Here, we report the oscillatory activities of mPFC–BLA circuit in reaction to a naturalistic threat, created by a predatory robot in mice. Specifically, we found dynamic frequency tuning among two different theta rhythms (~5 or ~10 Hz) was accompanied by agile changes of two different defensive behaviors (freeze-or-flight). By analyzing flight trajectories, we also found that high beta (~30 Hz) is engaged in the top–down process for goal-directed flights and accompanied by a reduction in fast gamma (60 to 120 Hz, peak near 70 Hz). The elevated beta nested the fast gamma activity by its phase more strongly. Our results suggest that the mPFC–BLA circuit has a potential role in oscillatory gear shifting allowing flexible information routing for behavior switches.
Mouse models of
SYNGAP1
-related intellectual disability
Authors: Araki Yoichi , Gerber Elizabeth E. , Rajkovich Kacey E. , Hong Ingie , Johnson Richard C. , Lee Hey-Kyoung , Kirkwood Alfredo , Huganir Richard L.
Published: September 2023

SYNGAP1 is a Ras-GTPase-activating protein highly enriched at excitatory synapses in the brain. De novo loss-of-function mutations in
SYNGAP1
are a major cause of genetically defined neurodevelopmental disorders (NDDs). These mutations are highly penetrant and cause
SYNGAP1
-related intellectual disability (SRID), an NDD characterized by cognitive impairment, social deficits, early-onset seizures, and sleep disturbances. Studies in rodent neurons have shown that Syngap1 regulates developing excitatory synapse structure and function, and heterozygous
Syngap1
knockout mice have deficits in synaptic plasticity, learning, and memory and have seizures. However, how specific
SYNGAP1
mutations found in humans lead to disease has not been investigated in vivo. To explore this, we utilized the CRISPR-Cas9 system to generate knock-in mouse models with two distinct known causal variants of SRID: one with a frameshift mutation leading to a premature stop codon,
SYNGAP1; L813RfsX22,
and a second with a single-nucleotide mutation in an intron that creates a cryptic splice acceptor site leading to premature stop codon,
SYNGAP1; c.3583-9G>A
. While reduction in
Syngap1
mRNA varies from 30 to 50% depending on the specific mutation, both models show ~50% reduction in Syngap1 protein, have deficits in synaptic plasticity, and recapitulate key features of SRID including hyperactivity and impaired working memory. These data suggest that half the amount of SYNGAP1 protein is key to the pathogenesis of SRID. These results provide a resource to study SRID and establish a framework for the development of therapeutic strategies for this disorder.
Nasal administration of anti-CD3 monoclonal antibody ameliorates disease in a mouse model of Alzheimer’s disease
Authors: Lopes Juliana R. , Zhang Xiaoming , Mayrink Julia , Tatematsu Bruna K. , Guo Lydia , LeServe Danielle S. , Abou-El-Hassan Hadi , Rong Felipe , Dalton Maria J. , Oliveira Marilia G. , Lanser Toby B. , Liu Lei , Butovsky Oleg , Rezende Rafael M. , Weiner Howard L.
Published: September 2023

Emerging evidence suggests that dysregulation of neuroinflammation, particularly that orchestrated by microglia, plays a significant role in the pathogenesis of Alzheimer’s disease (AD). Danger signals including dead neurons, dystrophic axons, phosphorylated tau, and amyloid plaques alter the functional phenotype of microglia from a homeostatic (M0) to a neurodegenerative or disease-associated phenotype, which in turn drives neuroinflammation and promotes disease. Thus, therapies that target microglia activation constitute a unique approach for treating AD. Here, we report that nasally administered anti-CD3 monoclonal antibody in the 3xTg AD mouse model reduced microglial activation and improved cognition independent of amyloid beta deposition. In addition, gene expression analysis demonstrated decreased oxidative stress, increased axogenesis and synaptic organization, and metabolic changes in the hippocampus and cortex of nasal anti-CD3 treated animals. The beneficial effect of nasal anti-CD3 was associated with the accumulation of T cells in the brain where they were in close contact with microglial cells. Taken together, our findings identify nasal anti-CD3 as a unique form of immunotherapy to treat Alzheimer’s disease independent of amyloid beta targeting.
A New Device Concept of Magnetic Confinement Deuterium–Deuterium Fusion
Authors: Pan 潘 Yuan 垣 , Wu 武 Songtao 松涛 , Wang 王 Zhijiang 之江 , Chen 陈 Zhipeng 志鹏 , Xu 许 Min 敏 , Rao 饶 Bo 波 , Zhu 朱 Ping 平 , Yang 杨 Yong 勇 , Zhang 张 Ming 明 , Ding 丁 Yonghua 永华 , Xia 夏 Donghui 冬辉
Published: September 2023

A two-stage cascade magnetic compression scheme based on field reversed configuration plasma is proposed. The temperature and density of plasma before and after magnetic compression are analyzed. In addition, the suppression of the two-fluid effect and the finite Larmor radius effect on the tilting mode and the rotating mode of major magnetic hydrodynamic instability is studied, and finally, the key physical and engineering parameters of the deuterium–deuterium fusion pulse device are introduced. Further analysis shows that the fusion neutrons can be produced at an energy flux of more than 2 MW/m2 per year, which meets the material testing requirements for the fusion demonstration reactor (DEMO). If the recovery of magnetic field energy is taken into account, net energy outputs may be achieved, indicating that the scheme has a potential application prospect as a deuterium–deuterium pulse fusion energy.
Pressure-Induced Superconductivity in the Charge-Density-Wave Compound LaTe2–x
Sb
x
(x = 0 and 0.4)
Authors: Chen 陈 Xu 旭 , Sun 孙 Pei-han 培函 , Xie 谢 Zhenkai 圳楷 , Meng 孟 Fanqi 繁琦 , Pei 裴 Cuiying 翠颖 , Qi 齐 Yanpeng 彦鹏 , Ying 应 Tianping 天平 , Liu 刘 Kai 凯 , Guo 郭 Jian-gang 建刚 , Chen 陈 Xiaolong 小龙
Published: September 2023

Magnetic CeTe2 achieving superconductivity under external pressure has received considerable attention. The intermingling of 4f and 5d electrons from Ce raised the speculation of an unconventional pairing mechanism arising from magnetic fluctuations. Here, we address this speculation using a nonmagnetic 4f-electron-free LaTe2 as an example. No structural phase transition can be observed up to 35 GPa in the in situ synchrotron diffraction patterns. Subsequent high-pressure electrical measurements show that LaTe2 exhibits superconductivity at 20 Gpa with its T
c (4.5 K) being two times higher than its Ce-counterpart. Detailed theoretical calculations reveal that charge transfer from the 4p orbitals of the planar square Te–Te network to the 5d orbitals of La is responsible for the emergence of superconductivity in LaTe2, as confirmed by Hall experiments. Furthermore, we study the modulation of q
CDW by Sb substitution and find a record high

T
c

onset

∼
6.5

K in LaTe1.6Sb0.4. Our work provides an informative clue to comprehend the role of 5d–4p hybridization in the relationship between charge density wave (CDW) and superconductivity in these RETe2 (RE = rare-earth elements) compounds.
The effect of Mn on structural, magnetic and magnetoresistance properties of Ni–Mn–Sb Heusler melt spun ribbons under extreme conditions
Authors: Sivaprakash P , Esakki Muthu S , Saravanan C , Rao N V Rama , Kim Ikhyun
Published: September 2023

Ni50 − x
Mn37 + x
Sb13 (NMS (x = 4–6)) melt-spun Heusler ribbon was fabricated by employing the arc melting technique. Also, the electrical, structural, and magnetic characteristics of melt-spun alloy ribbons with chemically increased Mn (a decrease in Ni concentration) content are also being investigated. Further, it has been noticed that, the Curie temperatures of the austenitic (T
C
A) phase and the martensitic phase transition temperature (T
M) are both shifted toward higher temperatures, by increasing the amount of Mn under 500 Oe (0.05 T) of applied magnetic fields. The discontinuity of field cooling (FC) and zero field cooling (ZFC) curves reveals the irreversibility of magnetization caused by inhomogeneous magnetic anisotropy lower the exchange bias (EB) (blocking bias) temperature. Furthermore, the disappearance of exchange bias (EB) in ribbon alloys with increasing temperature is supported by the fact that coercivity (H
C) gradually increases with temperature and increases at 40 K, and then decreases with temperature. Additionally, a −ΔS
Max of −5.21 Jkg−1·K−1 for a ribbon with x = 6 is acquired at 312 K with a 50 kOe (5 T) change in the applied magnetic field. Increases in Mn content result in −ΔS
M values in NMS alloy ribbons of −4.3, −4.7, and −5.2 Jkg−1·K−1 and the same trend is observed in negative magneto-resistance ((−MR) (%)) values of −9%, −11%, and −14% for x = 4–6, respectively. Here, the super zone boundary that is close to the Fermi surface is responsible for the change in −MR.
Size and density control of skyrmions with picometer CoFeB thickness variations—observation of zero-field skyrmions and skyrmion merging
Authors: Denker Christian , Nielsen Sören , Lage Enno , Römer-Stumm Malte , Heyen Hauke , Junk Yannik , Walowski Jakob , Waldorf Konrad , Münzenberg Markus , McCord Jeffrey
Published: September 2023

The controlled formation and adjustment of size and density of magnetic skyrmions in Ta/CoFeB/MgO trilayers with low Dzyaloshinskii–Moriya interaction is demonstrated. Close to the out-of-plane to in-plane magnetic spin reorientation transition, we find that small energy contributions enable skyrmion formation in a narrow window of 20 pm in CoFeB thickness. Zero-field stable skyrmions are established with proper magnetic field initialization within a 10 pm CoFeB thickness range. Using magneto-optical imaging with quantitative image processing, variations in skyrmion distribution and diameter are analyzed quantitatively, the latter for sizes well below the optical resolution limit. We demonstrate the controlled merging of individual skyrmions. The overall demonstrated degree of comprehension of skyrmion control aids to the development of envisioned skyrmion based magnetic memory devices.