Noncovalent interfaces play a vital role in inelastic deformation and toughening mechanisms in layered nanocomposites due to their dynamical recoverability. When interfacial engineering is applied to design layered na...Noncovalent interfaces play a vital role in inelastic deformation and toughening mechanisms in layered nanocomposites due to their dynamical recoverability. When interfacial engineering is applied to design layered nanocomposites, shear-lag analysis is usually implemented to evaluate the capability of interfacial loading transfer. Here, we introduce a multiscale shear-lag model that correlates macroscale mechanical properties with the molecular mechanisms to quantify the effects of interfacial configuration in graphene oxide(GO) layered nanocomposites. By investigating the mechanical responses of commensurate and incommensurate interfaces, we identify that the commensurate interface exhibits a pronounced size effect due to the nucleation and propagation of interfacial defects, whereas the incommensurate interface displays uniform deformation. Our predictions are further validated through large-scale molecular dynamics simulations for GO layered nanocomposites. This work demonstrates how size effects and interfacial configurations can be exploited to fabricate layered nanocomposites with superior mechanical properties despite relying on weak noncovalent interfaces.展开更多
With the discovery of the pivotal role of macrophages in tissue regeneration through shaping the tissue immune microenvironment, various immunomodulatory strategies have been proposed to modify traditional biomaterial...With the discovery of the pivotal role of macrophages in tissue regeneration through shaping the tissue immune microenvironment, various immunomodulatory strategies have been proposed to modify traditional biomaterials. Decellularized extracellular matrix (dECM) has been extensively used in the clinical treatment of tissue injury due to its favorable biocompatibility and similarity to the native tissue environment. However, most reported decellularization protocols may cause damage to the native structure of dECM, which undermines its inherent advantages and potential clinical applications. Here, we introduce a mechanically tunable dECM prepared by optimizing the freeze-thaw cycles. We demonstrated that the alteration in micromechanical properties of dECM resulting from the cyclic freeze-thaw process contributes to distinct macrophage-mediated host immune responses to the materials, which are recently recognized to play a pivotal role in determining the outcome of tissue regeneration. Our sequencing data further revealed that the immunomodulatory effect of dECM was induced via the mechnotrasduction pathways in macrophages. Next, we tested the dECM in a rat skin injury model and found an enhanced micromechanical property of dECM achieved with three freeze-thaw cycles significantly promoted the M2 polarization of macrophages, leading to superior wound healing. These findings suggest that the immunomodulatory property of dECM can be efficiently manipulated by tailoring its inherent micromechanical properties during the decellularization process. Therefore, our mechanics-immunomodulation-based strategy provides new insights into the development of advanced biomaterials for wound healing.展开更多
The Micro- and Nano-mechanics Working Group of the Chinese Society of Theoretical and Applied Mechanics organized a forum to discuss the perspectives, trends, and directions in mechanics of heterogeneous materials in ...The Micro- and Nano-mechanics Working Group of the Chinese Society of Theoretical and Applied Mechanics organized a forum to discuss the perspectives, trends, and directions in mechanics of heterogeneous materials in January 2010. The international journal, Acta Mechanica Solida Sinica, is de- voted to all fields of solid mechanics and relevant disciplines in science, technology, and engineering, with a balanced coverage on analytical, experimental, numerical and applied investigations. On the occasion of the 30TM anniversary of Acta Mechanica Solida Sinica, its editor-in-chief, Professor Q.S. Zheng invited some of the forum participants to review the state-of-the-art of mechanics of heterogeneous solids, with a particular emphasis on the recent research development results of Chinese scientists. Their reviews are organized into five research areas as reported in different sections of this paper. ~I firstly brings in fo- cus on micro- and nano-mechanics, with regards to several selective topics, including multiscale coupled models and computational methods, nanocrystal superlattices, surface effects, micromechanical damage mechanics, and microstructural evolution of metals and shape memory alloys. ~II shows discussions on multifield coupled mechanical phenomena, e.g., multi-fields actuations of liquid crystal polymer networks, mechanical behavior of materials under radiations, and micromechanics of heterogeneous materials. In ~III, we mainly address the multiscale mechanics of biological nanocomposites, biological adhesive surface mechanics, wetting and dewetting phenomena on microstructured solid surfaces. The phononic crystals and manipulation of elastic waves were elaborated in ~IV. Finally, we conclude with a series of perspectives on solid mechanics. This review will set a primary goal of future science research and engineering application on solid mechanics with the effort of social and economic development.展开更多
Multimodal image fusion plays an important role in image analysis and applications.Multimodal medical image fusion helps to combine contrast features from two or more input imaging modalities to represent fused inform...Multimodal image fusion plays an important role in image analysis and applications.Multimodal medical image fusion helps to combine contrast features from two or more input imaging modalities to represent fused information in a single image.One of the critical clinical applications of medical image fusion is to fuse anatomical and functional modalities for rapid diagnosis of malignant tissues.This paper proposes a multimodal medical image fusion network(MMIF-Net)based on multiscale hybrid attention.The method first decomposes the original image to obtain the low-rank and significant parts.Then,to utilize the features at different scales,we add amultiscalemechanism that uses three filters of different sizes to extract the features in the encoded network.Also,a hybrid attention module is introduced to obtain more image details.Finally,the fused images are reconstructed by decoding the network.We conducted experiments with clinical images from brain computed tomography/magnetic resonance.The experimental results show that the multimodal medical image fusion network method based on multiscale hybrid attention works better than other advanced fusion methods.展开更多
Mechanical properties of shales are key parameters influencing hydrocarbon production – impacting borehole stability, hydraulic fracture extension and microscale variations in in situ stress. We use Ordovician shale(...Mechanical properties of shales are key parameters influencing hydrocarbon production – impacting borehole stability, hydraulic fracture extension and microscale variations in in situ stress. We use Ordovician shale(Sichuan Basin, China) as a type-example to characterize variations in mineral particle properties at microscale including particle morphology, form of contact and spatial distribution via mineral liberation analysis(MLA) and scanning electron microscopy(SEM). Deformation-based constitutive models are then built using finite element methods to define the impact of various architectures of fracture and mineral distributions at nanometer scale on the deformation characteristics at macroscale.Relative compositions of siliceous, calcareous and clay mineral particles are shown to be the key factors influencing brittleness. Shales with similar mineral composition show a spectrum of equivalent medium mechanical properties due to differing particle morphology and mineral heterogeneity. The predominance of small particles and/or point-point contacts are conducive to brittle failure, in general, and especially so when quartz-rich. Fracture morphology, length and extent of filling all influence shale deformability. High aspect-ratio fractures concentrate stress at fracture tips and are conducive to extension, as when part-filled by carbonate minerals. As fracture spacing increases, stress transfer between adjacent fractures weakens, stress concentrations are amplified and fracture extension is favored. The higher the fractal dimension of the fracture and heterogeneity of the host the more pervasive the fractures. Moreover, when fractures extend, their potential for intersection and interconnection contributes to a reduction in strength and the promotion of brittle failure. Thus, these results provide important theoretical insights into the role of heterogeneity on the deformability and strength of shale reservoirs with practical implications for their stimulation and in the recovery of hydrocarbons from them.展开更多
With the development of smart agriculture,accurately identifying crop diseases through visual recognition techniques instead of by eye has been a significant challenge.This study focused on apple leaf disease,which is...With the development of smart agriculture,accurately identifying crop diseases through visual recognition techniques instead of by eye has been a significant challenge.This study focused on apple leaf disease,which is closely related to the final yield of apples.A multiscale fusion dense network combined with an efficient multiscale attention(EMA)mechanism called Incept_EMA_DenseNet was developed to better identify eight complex apple leaf disease images.Incept_EMA_DenseNet consists of three crucial parts:the inception module,which substituted the convolution layer with multiscale fusion methods in the shallow feature extraction layer;the EMA mechanism,which is used for obtaining appropriate weights of different dense blocks;and the improved DenseNet based on DenseNet_121.Specifically,to find appropriate multiscale fusion methods,the residual module and inception module were compared to determine the performance of each technique,and Incept_EMA_DenseNet achieved an accuracy of 95.38%.Second,this work used three attention mechanisms,and the efficient multiscale attention mechanism obtained the best performance.Third,the convolution layers and bottlenecks were modified without performance degradation,reducing half of the computational load compared with the original models.Incept_EMA_DenseNet,as proposed in this paper,has an accuracy of 96.76%,being 2.93%,3.44%,and 4.16%better than Resnet50,DenseNet_121 and GoogLeNet,respectively,proved to be reliable and beneficial,and can effectively and conveniently assist apple growers with leaf disease identification in the field.展开更多
Nucleus pulposus(NP)tissue engineering brings new hope in the repair of intervertebral disc degeneration(IVDD).IVDD is often accompanied by multiscale changes in the mechanical microenvironment,including the changes o...Nucleus pulposus(NP)tissue engineering brings new hope in the repair of intervertebral disc degeneration(IVDD).IVDD is often accompanied by multiscale changes in the mechanical microenvironment,including the changes of mechanical property of collagen fibril,NP tissue,and mechanical instability of spine.In this study,a multiscale mechanically-adapted strategy is proposed to promote NP repair.To achieve this goal,a viscoelasticadapted dual-network hydrogel(PVA-DN)is constructed.The hydrogel with multiscale tunable viscoelasticity and dynamic compression condition is used to meet the multiscale mechanical requirements of NP regeneration.The results show that the viscoelastic hydrogel promotes the proliferation,migration and adhesion of nucleus pulposus cell(NPC)as well as the secretion of NP-specific extracellular matrix.RNA-seq results show that it attenuates the inflammatory microenvironment by inhibiting the IL-17 signaling pathway.Appropriate dynamic compression applied to the viscoelastic scaffold further promotes the physiological function of NPC,and the viscoelasticity of hydrogel protects against NPC damage induced by excessive compression.Animal experiments demonstrate that the viscoelastic hydrogel effectively restores disc mechanical function and delays disc degen-eration in rats.Findings from this study highlight that the multiscale mechanically-adapted strategy is effective in the repair of IVDD.展开更多
基金jointly supported by the National Natural Science Foundation of China(Nos.11872063 and 12172346)the University of Science and Technology of China(USTC)Research Funds of the Double First-Class Initiative(No.YD2480002002)China Postdoctoral Science Foundation(No.2021TQ0323)。
文摘Noncovalent interfaces play a vital role in inelastic deformation and toughening mechanisms in layered nanocomposites due to their dynamical recoverability. When interfacial engineering is applied to design layered nanocomposites, shear-lag analysis is usually implemented to evaluate the capability of interfacial loading transfer. Here, we introduce a multiscale shear-lag model that correlates macroscale mechanical properties with the molecular mechanisms to quantify the effects of interfacial configuration in graphene oxide(GO) layered nanocomposites. By investigating the mechanical responses of commensurate and incommensurate interfaces, we identify that the commensurate interface exhibits a pronounced size effect due to the nucleation and propagation of interfacial defects, whereas the incommensurate interface displays uniform deformation. Our predictions are further validated through large-scale molecular dynamics simulations for GO layered nanocomposites. This work demonstrates how size effects and interfacial configurations can be exploited to fabricate layered nanocomposites with superior mechanical properties despite relying on weak noncovalent interfaces.
基金supported by National Natural Science Foundation of China(82071167,82001095,81970975,81901055,82201124,82201119)China Postdoctoral Science Foundation(2021TQ0379,2022M713575)+2 种基金Guangdong Basic and Applied Basic Research Foundation(2021A1515110380,2023A1515011963)Health and Medical Research Fund(No.09201466)the Food and Health Bureau,the Government of the HKSAR,China.
文摘With the discovery of the pivotal role of macrophages in tissue regeneration through shaping the tissue immune microenvironment, various immunomodulatory strategies have been proposed to modify traditional biomaterials. Decellularized extracellular matrix (dECM) has been extensively used in the clinical treatment of tissue injury due to its favorable biocompatibility and similarity to the native tissue environment. However, most reported decellularization protocols may cause damage to the native structure of dECM, which undermines its inherent advantages and potential clinical applications. Here, we introduce a mechanically tunable dECM prepared by optimizing the freeze-thaw cycles. We demonstrated that the alteration in micromechanical properties of dECM resulting from the cyclic freeze-thaw process contributes to distinct macrophage-mediated host immune responses to the materials, which are recently recognized to play a pivotal role in determining the outcome of tissue regeneration. Our sequencing data further revealed that the immunomodulatory effect of dECM was induced via the mechnotrasduction pathways in macrophages. Next, we tested the dECM in a rat skin injury model and found an enhanced micromechanical property of dECM achieved with three freeze-thaw cycles significantly promoted the M2 polarization of macrophages, leading to superior wound healing. These findings suggest that the immunomodulatory property of dECM can be efficiently manipulated by tailoring its inherent micromechanical properties during the decellularization process. Therefore, our mechanics-immunomodulation-based strategy provides new insights into the development of advanced biomaterials for wound healing.
文摘The Micro- and Nano-mechanics Working Group of the Chinese Society of Theoretical and Applied Mechanics organized a forum to discuss the perspectives, trends, and directions in mechanics of heterogeneous materials in January 2010. The international journal, Acta Mechanica Solida Sinica, is de- voted to all fields of solid mechanics and relevant disciplines in science, technology, and engineering, with a balanced coverage on analytical, experimental, numerical and applied investigations. On the occasion of the 30TM anniversary of Acta Mechanica Solida Sinica, its editor-in-chief, Professor Q.S. Zheng invited some of the forum participants to review the state-of-the-art of mechanics of heterogeneous solids, with a particular emphasis on the recent research development results of Chinese scientists. Their reviews are organized into five research areas as reported in different sections of this paper. ~I firstly brings in fo- cus on micro- and nano-mechanics, with regards to several selective topics, including multiscale coupled models and computational methods, nanocrystal superlattices, surface effects, micromechanical damage mechanics, and microstructural evolution of metals and shape memory alloys. ~II shows discussions on multifield coupled mechanical phenomena, e.g., multi-fields actuations of liquid crystal polymer networks, mechanical behavior of materials under radiations, and micromechanics of heterogeneous materials. In ~III, we mainly address the multiscale mechanics of biological nanocomposites, biological adhesive surface mechanics, wetting and dewetting phenomena on microstructured solid surfaces. The phononic crystals and manipulation of elastic waves were elaborated in ~IV. Finally, we conclude with a series of perspectives on solid mechanics. This review will set a primary goal of future science research and engineering application on solid mechanics with the effort of social and economic development.
基金supported by Qingdao Huanghai University School-Level ScientificResearch Project(2023KJ14)Undergraduate Teaching Reform Research Project of Shandong Provincial Department of Education(M2022328)+1 种基金National Natural Science Foundation of China under Grant(42472324)Qingdao Postdoctoral Foundation under Grant(QDBSH202402049).
文摘Multimodal image fusion plays an important role in image analysis and applications.Multimodal medical image fusion helps to combine contrast features from two or more input imaging modalities to represent fused information in a single image.One of the critical clinical applications of medical image fusion is to fuse anatomical and functional modalities for rapid diagnosis of malignant tissues.This paper proposes a multimodal medical image fusion network(MMIF-Net)based on multiscale hybrid attention.The method first decomposes the original image to obtain the low-rank and significant parts.Then,to utilize the features at different scales,we add amultiscalemechanism that uses three filters of different sizes to extract the features in the encoded network.Also,a hybrid attention module is introduced to obtain more image details.Finally,the fused images are reconstructed by decoding the network.We conducted experiments with clinical images from brain computed tomography/magnetic resonance.The experimental results show that the multimodal medical image fusion network method based on multiscale hybrid attention works better than other advanced fusion methods.
基金supported by the National Natural Science Foundation of China (Grant No. 42072194, U1910205)the Fundamental Research Funds for the Central Universities (800015Z1190, 2021YJSDC02)。
文摘Mechanical properties of shales are key parameters influencing hydrocarbon production – impacting borehole stability, hydraulic fracture extension and microscale variations in in situ stress. We use Ordovician shale(Sichuan Basin, China) as a type-example to characterize variations in mineral particle properties at microscale including particle morphology, form of contact and spatial distribution via mineral liberation analysis(MLA) and scanning electron microscopy(SEM). Deformation-based constitutive models are then built using finite element methods to define the impact of various architectures of fracture and mineral distributions at nanometer scale on the deformation characteristics at macroscale.Relative compositions of siliceous, calcareous and clay mineral particles are shown to be the key factors influencing brittleness. Shales with similar mineral composition show a spectrum of equivalent medium mechanical properties due to differing particle morphology and mineral heterogeneity. The predominance of small particles and/or point-point contacts are conducive to brittle failure, in general, and especially so when quartz-rich. Fracture morphology, length and extent of filling all influence shale deformability. High aspect-ratio fractures concentrate stress at fracture tips and are conducive to extension, as when part-filled by carbonate minerals. As fracture spacing increases, stress transfer between adjacent fractures weakens, stress concentrations are amplified and fracture extension is favored. The higher the fractal dimension of the fracture and heterogeneity of the host the more pervasive the fractures. Moreover, when fractures extend, their potential for intersection and interconnection contributes to a reduction in strength and the promotion of brittle failure. Thus, these results provide important theoretical insights into the role of heterogeneity on the deformability and strength of shale reservoirs with practical implications for their stimulation and in the recovery of hydrocarbons from them.
基金fully supported by the National Natural Science Foundation of China(52072412)。
文摘With the development of smart agriculture,accurately identifying crop diseases through visual recognition techniques instead of by eye has been a significant challenge.This study focused on apple leaf disease,which is closely related to the final yield of apples.A multiscale fusion dense network combined with an efficient multiscale attention(EMA)mechanism called Incept_EMA_DenseNet was developed to better identify eight complex apple leaf disease images.Incept_EMA_DenseNet consists of three crucial parts:the inception module,which substituted the convolution layer with multiscale fusion methods in the shallow feature extraction layer;the EMA mechanism,which is used for obtaining appropriate weights of different dense blocks;and the improved DenseNet based on DenseNet_121.Specifically,to find appropriate multiscale fusion methods,the residual module and inception module were compared to determine the performance of each technique,and Incept_EMA_DenseNet achieved an accuracy of 95.38%.Second,this work used three attention mechanisms,and the efficient multiscale attention mechanism obtained the best performance.Third,the convolution layers and bottlenecks were modified without performance degradation,reducing half of the computational load compared with the original models.Incept_EMA_DenseNet,as proposed in this paper,has an accuracy of 96.76%,being 2.93%,3.44%,and 4.16%better than Resnet50,DenseNet_121 and GoogLeNet,respectively,proved to be reliable and beneficial,and can effectively and conveniently assist apple growers with leaf disease identification in the field.
基金supported by the National Natural Science Foundation of China(32201070,32171350,32471410,32171321,81925027,32130059)Jiangsu Basic Research Program(Natural Science Founda-tion)(BK20240019,BK20240020)+3 种基金International Cooperation Project of Ningbo City(2023H013)Medical and Health Science and Technology Innovation Project of Suzhou(SKY2022105)Basic cutting-edge innovation cross project of Suzhou Medical College of Soochow University(YXY2302010)the Priority Academic Program Development of Jiangsu Higher Education Institutions(PAPD).
文摘Nucleus pulposus(NP)tissue engineering brings new hope in the repair of intervertebral disc degeneration(IVDD).IVDD is often accompanied by multiscale changes in the mechanical microenvironment,including the changes of mechanical property of collagen fibril,NP tissue,and mechanical instability of spine.In this study,a multiscale mechanically-adapted strategy is proposed to promote NP repair.To achieve this goal,a viscoelasticadapted dual-network hydrogel(PVA-DN)is constructed.The hydrogel with multiscale tunable viscoelasticity and dynamic compression condition is used to meet the multiscale mechanical requirements of NP regeneration.The results show that the viscoelastic hydrogel promotes the proliferation,migration and adhesion of nucleus pulposus cell(NPC)as well as the secretion of NP-specific extracellular matrix.RNA-seq results show that it attenuates the inflammatory microenvironment by inhibiting the IL-17 signaling pathway.Appropriate dynamic compression applied to the viscoelastic scaffold further promotes the physiological function of NPC,and the viscoelasticity of hydrogel protects against NPC damage induced by excessive compression.Animal experiments demonstrate that the viscoelastic hydrogel effectively restores disc mechanical function and delays disc degen-eration in rats.Findings from this study highlight that the multiscale mechanically-adapted strategy is effective in the repair of IVDD.
