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On breakthroughs and limits: Resolving structural fine-tuning of photosynthetic supercomplexes

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Molecular Plant 2024年第2期17卷 224-226页

作者： Eunchul Kim Marcel Dann division of Environmental Photobiology National Institute for Basic BiologySOKENDAlOkazaki 444-8585Japan Department of Basic biology The Graduate University for Advanced StudiesSOKENDAlOkazaki 444-8585Japan Bio-Inspired Energy Conversion Technical University of DarmstadtSchnittspahnstraBe 1064287 DarmstadtGermany

Dynamic regulation of photosynthetic supercomplexes is a key strategy allowing plants to adjust their light-harvesting system in response to varying environmental light conditions(Bassi and Dall'Osto,2021).State transition(i.e.,acclimative re-distribution of peripheral antennae between photosystems[PSs]I and II)is one such regulation mechanism that maintains excitation balance between PSl and PSll.

关键词： complexes breakthrough maintain

Application of CFD and FEA Coupling to Predict structural Dynamic Responses of A Trimaran in Uni-and Bi-Directional Waves

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China Ocean Engineering 2024年第1期38卷 81-92页

作者： LIAO Xi-yu XIA Jin-song CHEN Zhan-yang TANG Qin ZHAO Nan ZHAO Wei-dong GUI Hong-bin Marine Design&Research Institute of China Shanghai 200011China Ship Structure division China Ship Scientific Research CenterWuxi 214082China College of Ocean Engineering Harbin Institute of TechnologyWeihaiWeihai 264209China State Key Laboratory of structural Analysis Optimization and CAE Software for Industrial EquipmentDalian University of TechnologyDalian 116024China School of Foreign Studies Jiangnan UniversityWuxi 214122China

To predict the wave loads of a flexible trimaran in different wave fields,a one-way interaction numerical simulation method is proposed by integrating the fluid solver(Star-CCM+)and structural solver(Abaqus).Differing from the existing coupled CFD-FEA method for monohull ships in head waves,the presented method equates the mass and stiffness of the whole ship to the hull shell so that any transverse and longitudinal section stress of the hull in oblique waves can be obtained.Firstly,verification study and sensitivity analysis are carried out by comparing the trimaran motions using different mesh sizes and time step schemes.Discussion on the wave elevation of uni-and bi-directional waves is also carried out.Then a comprehensive analysis on the structural responses of the trimaran in different uni-directional regular wave and bi-directional cross sea conditions is carried out,respectively.Finally,the differences in structural response characteristics of trimaran in different wave fields are studied.The results show that the present method can reduce the computational burden of the two-way fluid-structure interaction simulations.

关键词： CFD-FEA fluid-structure coupling structural responses trimaran bi-directional cross sea

Resident immune responses to spinal cord injury:role of astrocytes and microglia

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Neural Regeneration Research 2024年第8期19卷 1678-1685页

作者： Sydney Brockie Cindy Zhou Michael G.Fehlings division of Genetics and Development Krembil Research InstituteUniversity Health NetworkTorontoONCanada Institute of Medical Science University of TorontoTorontoONCanada division of Neurosurgery and Spine Program Department of SurgeryUniversity of TorontoTorontoONCanada

Spinal cord injury can be traumatic or non-traumatic in origin,with the latter rising in incidence and prevalence with the aging demographics of our society.Moreove r,as the global population ages,individuals with co-existent degenerative spinal pathology comprise a growing number of traumatic spinal cord injury cases,especially involving the cervical spinal cord.This makes recovery and treatment approaches particula rly challenging as age and comorbidities may limit regenerative capacity.For these reasons,it is critical to better understand the complex milieu of spinal cord injury lesion pathobiology and the ensuing inflammatory response.This review discusses microglia-specific purinergic and cytokine signaling pathways,as well as microglial modulation of synaptic stability and plasticity after injury.Further,we evaluate the role of astrocytes in neurotransmission and calcium signaling,as well as their border-forming response to neural lesions.Both the inflammatory and reparative roles of these cells have eluded our complete understanding and remain key therapeutic targets due to their extensive structural and functional roles in the nervous system.Recent advances have shed light on the roles of glia in neurotransmission and reparative injury responses that will change how interventions are directed.Understanding key processes and existing knowledge gaps will allow future research to effectively target these cells and harness their regenerative potential.

关键词： astrocytes glial signaling microglia spinal cord injury synaptic transmission

Solid-state impedance spectroscopy studies of dielectric properties and relaxation processes in Na_(2)O–V_(2)O_(5)–Nb_(2)O_(5)–P_(2)O_(5) glass

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International Journal of Minerals,Metallurgy and Materials 2024年第1期31卷 186-196页

作者： Sara Marijan Luka Pavic division of Materials Chemistry Ruđer Boskovic InstituteBijenicka 54HR-10000 ZagrebCroatia

Solid-state impedance spectroscopy(SS-IS)was used to investigate the influence of structural modifications resulting from the addition of Nb2O5 on the dielectric properties and relaxation processes in the quaternary mixed glass former(MGF)system 35Na_(2)O–10V_(2)O_(5)–(55-x)P_(2)O_(5)–xNb_(2)O_(5)(x=0–40,mol%).The dielectric parameters,including the dielectric strength and dielectric loss,are determined from the frequency and temperature-dependent complex permittivity data,revealing a significant dependence on the Nb2O5 content.The transition from a predominantly phosphate glass network(x<10,region I)to a mixed niobate–phosphate glass net-work(10≤x≤20,region II)leads to an increase in the dielectric parameters,which correlates with the observed trend in the direct-cur-rent(DC)conductivity.In the predominantly niobate network(x≥25,region III),the highly polarizable nature of Nb5+ions leads to a fur-ther increase in the dielectric permittivity and dielectric strength.This is particularly evident in Nb-40 glass-ceramic,which contains Na_(13)Nb_(35)O_(94) crystalline phase with a tungsten bronze structure and exhibits the highest dielectric permittivity of 61.81 and the lowest loss factor of 0.032 at 303 K and 10 kHz.The relaxation studies,analyzed through modulus formalism and complex impedance data,show that DC conductivity and relaxation processes are governed by the same mechanism,attributed to ionic conductivity.In contrast to glasses with a single peak in frequency dependence of imaginary part of electrical modulus,M″(ω),Nb-40 glass-ceramic exhibits two distinct contributions with similar relaxation times.The high-frequency peak indicates bulk ionic conductivity,while the additional low-fre-quency peak is associated with the grain boundary effect,confirmed by the electrical equivalent circuit(EEC)modelling.The scaling characteristics of permittivity and conductivity spectra,along with the electrical modulus,validate time-temperature superposition and demonstrate a strong correlation with composition and modific

关键词： phosphate glasses glass-ceramics impedance spectroscopy dielectric properties relaxation processes permittivity scaling conductivity scaling modulus formalism

A new neural-network-based method for structural damage identification in single-layer reticulated shells

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Frontiers of structural and Civil Engineering 2024年第1期18卷 104-121页

作者： Jindong ZHANG Xiaonong GUO Shaohan ZONG Yujian ZHANG College of Civil Engineering Tongji UniversityShanghai 200092China China Construction Eighth Engineering division Co. Ltd.Shanghai 200135China

Single-layer reticulated shells(SLRSs)find widespread application in the roofs of crucial public structures,such as gymnasiums and exhibition center.In this paper,a new neural-network-based method for structural damage identification in SLRSs is proposed.First,a damage vector index,NDL,that is related only to the damage localization,is proposed for SLRSs,and a damage data set is constructed from NDL data.On the basis of visualization of the NDL damage data set,the structural damaged region locations are identified using convolutional neural networks(CNNs).By cross-dividing the damaged region locations and using parallel CNNs for each regional location,the damaged region locations can be quickly and efficiently identified and the undamaged region locations can be eliminated.Second,a damage vector index,DS,that is related to the damage location and damage degree,is proposed for SLRSs.Based on the damaged region identified previously,a fully connected neural network(FCNN)is constructed to identify the location and damage degree of members.The effectiveness and reliability of the proposed method are verified by considering a numerical case of a spherical SLRS.The calculation results showed that the proposed method can quickly eliminate candidate locations of potential damaged region locations and precisely determine the location and damage degree of members.

关键词： single-layer reticulated shell damage identification neural network convolutional neural network cross-partitioning method

Friction Characteristics Between Marine Clay and Construction Materials

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Journal of Ocean University of China 2024年第2期23卷 427-437页

作者： KOU Hailei HUANG Jiaming CHENG Yang College of Engineering Ocean University of ChinaQingdao 266100China Fourth division Organization Department of the CPC Qingdao Municipal CommitteeQingdao 266100China

Structure-soil interface friction characteristics is of importance to investigate the interaction between engineering structures and soils,especially for offshore structures.The interface friction behavior between marine clay and structural materials with different roughness was studied in this paper by using 3D optical scanning tests,a modified direct shear device and numerical simulation.Relationships between the surface roughness of structures,water content and interface friction angle were presented by model tests.The increase of water contents decreased the interface friction angles.For interfaces with different roughness,the interface friction angles will be smaller than that of the soil when the water content exceeds a certain value.The roughness of the interface and the water content of the soil are mutually coupled to influence the coefficient of friction(COF).This paper proposed a Finite Element Method(FEM)to simulate the interface direct shear tests of structures with different roughness.The surface models with different roughness are established based on the structure data obtained by 3D scanning.The Coupled Eulerian-Lagrangian(CEL)approach was employed to analyse soils sheared by irregular surfaces.The interface behavior for interfaces with different roughness under cyclic shear stresses was analyzed by FEM.

关键词： marine clay construction material interface friction behavior surface roughness Finite Element Method

Bioceramic scaffolds with two-step internal/external modification of copper-containing polydopamine enhance antibacterial and alveolar bone regeneration capability

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Journal of Zhejiang University-Science B(Biomedicine & Biotechnology) 2024年第1期25卷 65-82页

作者： Xiaojian JIANG Lihong LEI Weilian SUN Yingming WEI Jiayin HAN Shuaiqi ZHONG Xianyan YANG Zhongru GOU Lili CHEN Department of Oral Medicine the Second Affiliated HospitalZhejiang University School of MedicineHangzhou310009China Bio-nanomaterials and Regenerative Medicine Research division Zhejiang–California International Nanosystem InstituteZhejiang UniversityHangzhou310058China

Magnesium-doped calcium silicate(CS)bioceramic scaffolds have unique advantages in mandibular defect repair;however,they lack antibacterial properties to cope with the complex oral microbiome.Herein,for the first time,the CS scaffold was functionally modified with a novel copper-containing polydopamine(PDA(Cu^(2+)))rapid deposition method,to construct internally modified(*P),externally modified(@PDA),and dually modified(*P@PDA)scaffolds.The morphology,degradation behavior,and mechanical properties of the obtained scaffolds were evaluated in vitro.The results showed that the CS*P@PDA had a unique micro-/nano-structural surface and appreciable mechanical resistance.During the prolonged immersion stage,the release of copper ions from the CS*P@PDA scaffolds was rapid in the early stage and exhibited long-term sustained release.The in vitro evaluation revealed that the release behavior of copper ions ascribed an excellent antibacterial effect to the CS*P@PDA,while the scaffolds retained good cytocompatibility with improved osteogenesis and angiogenesis effects.Finally,the PDA(Cu^(2+))-modified scaffolds showed effective early bone regeneration in a critical-size rabbit mandibular defect model.Overall,it was indicated that considerable antibacterial property along with the enhancement of alveolar bone regeneration can be imparted to the scaffold by the two-step PDA(Cu^(2+))modification,and the convenience and wide applicability of this technique make it a promising strategy to avoid bacterial infections on implants.

关键词： Copper-containing polydopamine Modification Antibacterial property Bone regeneration Angiogenesis Bioceramic scaffold

Performance assessment of prefabricated vertical drains in mitigating soil reliquefaction subjected to repeated seismic events using shaking table experiments

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Frontiers of structural and Civil Engineering 2024年第3期18卷 411-427页

作者： Gowtham PADMANABHAN Ganesh Kumar SHANMUGAM Department of Earthquake Engineering Indian Institute of Technology RoorkeeUttarakhand 247667India Geotechnical Engineering division CSIR-Central Building Research Institute Academy of Scientific and Innovative Research(AcSIR)Uttarakhand 247667India

The use of prefabricated vertical drains(PVD)in liquefiable deposits is gaining attention due to enhanced drainage.However,investigations on PVD in mitigating re-liquefaction during repeated shaking events are not available.This study performed a series of shaking table experiments on untreated and PVD-treated specimens prepared with 40%and 60%relative density.Repeated sinusoidal loading was applied with an incremental peak acceleration of 0.1g,0.2g,0.3g,and 0.4g,at 5 Hz shaking frequency with 40 s duration.The performance of treated ground was evaluated based on the generation and dissipation of excess pore water pressure(EPWP),induced sand densification,subsidence,and cyclic stress ratio.In addition,the strain accumulated in fresh and exhumed PVD was investigated using geotextile tensile testing apparatus aided with digital image correlation.No evidence of pore pressure was reported up to 0.2g peak acceleration for 40%and 60%relative density specimens.The continuous occurrence of soil densification and drainage medium restrained and delayed the generation of EPWP and expedited the dissipation process.This study demonstrates PVD can mitigate re-liquefaction,without suffering from deterioration,when subjected to medium to high intense repeated shaking events.

关键词： prefabricated vertical drains drainage re-liquefaction shaking table digital image correlation

Utilizing a metal-forging inspired chain combing strategy to enhance properties and expand applications of Nylon 66 plastic via heat inducing

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Nano Research 2024年第3期17卷 2164-2171页

作者： Junyu Yang Jiangwei Zhang Nan Wang Guangyuan Zhou division of Energy Materials Daglian Institute of Chemical PhysicsChinese Academy of SciencesDalian 116023China Innovation Center of Energy Material and Chemistry College of Chemistry and Chemical EngineeringInner Mongolia UniversityHohhot 010021China

The mechanical properties of engineering plastics can be enhanced through effective surface mechanical treatment(SMT),which can be applied to various types of engineering plastics,eliminating the limitations of conventional polymer processing and could potentially extend their applications and improve their performance and reliability as structural-functional materials.Inspired by metal forging,this work proposes a simple and effective SMT strategy to enhance the mechanical properties of polyamide 66(PA66).Tensile tests have shown that SMTed PA66 samples exhibit significant improvements in both Young’s modulus and ultimate tensile strength(UTS),with a 2104 MPa Young’s modulus,almost double that of the pristine samples,and a 35.56%increase in UTS,reaching 183 MPa.Additionally,the modulus within the localized SMTed surface layer could reach up to 14 GPa,which is approximately 14 times higher than that of the pristine sample.The Vickers hardness within the localized SMTed surface layer can be doubled,reaching 10.72 Hv,and the crystallinity can increase by approximately 20%compared to the untreated region.Furthermore,force field molecular dynamics(FFMD)simulations were conducted to investigate the ternary relationship between the SMT method,PA66’s molecular structure,and its properties.The combination of MD simulations and versatile structural characterizations provides evidence that the SMT method’s mechanism,under heat induction,results in a chain-combing procedure that changes the polymer’s molecular morphology microscopically and enhances its mechanical properties macroscopically.

关键词： Nylon 66 mechanical properties hardness crystallinity structural characterizations molecular dynamics simulation