A novel reconstructive prosthesis was designed with topological optimization(TO)and a lattice structure to enhance biomechanical and biological properties in the proximal tibia.The biomechanical performance was valida...A novel reconstructive prosthesis was designed with topological optimization(TO)and a lattice structure to enhance biomechanical and biological properties in the proximal tibia.The biomechanical performance was validated through finite element analysis(FEA)and biomechanical tests.The tibia with inhomogeneous material properties was reconstructed according to computed tomography images,and different components were designed to simulate the operation.Minimum compliance TO subject to a volume fraction constraint combined with a graded lattice structure was utilized to redesign the prosthesis.FEA was performed to evaluate the mechanical performances of the tibia and implants after optimization,including stress,micromotion,and strain energy.The results were analyzed by paired-samples t tests,and p<0.05 was considered significant.Biomechanical testing was used to verify the tibial stresses.Compared to the original group(OG),the TO group(TOG)exhibited lower stress on the stem,and the maximum von Mises stresses were 87.2 and 53.1 MPa,respectively,a 39.1%reduction(p<0.05).Conversely,the stress and strain energy on the tibia increased in the TOG.The maximum von Mises stress values were 16.4 MPa in the OG and 22.9 MPa in the TOG with a 39.6%increase(p<0.05),and the maximum SED value was 0.026 MPa in the OG and 0.042 MPa in the TOG,corresponding to an increase of 61.5%(p<0.05).The maximum micromotions in the distal end of the stem were 135μm in the OG and 68μm in the TOG,almost a 50%reduction.The stress curves of the biomechanical test coincided well with the FEA results.The TO approach can effectively reduce the whole weight of the prosthesis and improve the biomechanical environment of the tibia.It could also pave the way for next-generation applications in orthopedics surgery.展开更多
With the population aging and an increasing desire for a high quality of life,millions of patients who suffered knee arthropathy have undergone total knee arthroplasty （TKA）.Although the success rate for primary TKA...With the population aging and an increasing desire for a high quality of life,millions of patients who suffered knee arthropathy have undergone total knee arthroplasty （TKA）.Although the success rate for primary TKA has been quite high,the number of revision surgeries can not be ignored.Bone loss is one of the challenges confronting surgeons who perform revision TKAs as it can impair alignment accuracy and the long-term stability of the implant.Although several options are available for bone loss after TKA--cement,bone grafting,standard augments,and hinged implants--there is no single ideal option available for all patients with a severe bone defect because of the variety and severity of the defects.1 The burgeoning rapid prototyping （RP） technique,which has been used to fabricate components with complex and unique structures,may offer a novel option in these cases.Keywords：rapid prototyping; severe bone defects; knee展开更多
Mechanical vibration defect is the key factor leading to sudden failure of gas-insulated switchgear(GIS)equipment.It is important to realise effective prediction of the me-chanical vibration state development trend of...Mechanical vibration defect is the key factor leading to sudden failure of gas-insulated switchgear(GIS)equipment.It is important to realise effective prediction of the me-chanical vibration state development trend of GIS equipment in order to improve its active safety protection level.This paper carried out research on the accurate prediction method and experimental validation of the mechanical vibration state and its defect severity development trend for the GIS equipment.Firstly,the deep and shallow vibration feature parameters for different mechanical defect signals were jointly extracted by time-domain features and deep belief network methods.Secondly,a new prediction model,incorporating the attention mechanism and the bidirectional gated recurrent unit(BiGRU),was constructed with the deep and shallow vibration feature parameters as inputs.Finally,the prediction trend effectiveness was verified based on the real-type GIS mechanical simulation platform and the field operation GIS equipment.Results show that the deep and shallow vibration feature extraction method proposed in this paper can characterise the mechanical defect information more comprehensively.The new prediction method of the vibration state trend based on the attention-BiGRU model shows ideal accuracy,and the predicted vibration state development trend is highly consistent with the actual,with an average absolute error of 0.063.The root mean square error(ERMSE)value of the prediction method is<5%,which reduces the relative error value at least 37% compared with the traditional prediction models.This paper provides a valuable reference for the proactive defence of GIS mechanical failure.展开更多
Regeneration of severe bone defects remains an enormous challenge in clinic.Developing regenerative scaffolds to directionally guide bone growth is a potential strategy to overcome this hurdle.Conch,an interesting cre...Regeneration of severe bone defects remains an enormous challenge in clinic.Developing regenerative scaffolds to directionally guide bone growth is a potential strategy to overcome this hurdle.Conch,an interesting creature widely spreading in ocean,has tough spiral shell that can continuously grow along the spiral direction.Herein,inspired by the physiological features of conches,a conch-like(CL)scaffold based onβ-TCP bioceramic material was successfully prepared for guiding directional bone growth via digital light processing(DLP)-based 3D printing.Benefiting from the spiral structure,the CL scaffolds significantly improved cell adhesion,proliferation and osteogenic differentiation in vitro compared to the conventional 3D scaffolds.Particularly,the spiral structure in the scaffolds could efficiently induce cells to migrate from the bottom to the top of the scaffolds,which was like“cells climbing stairs”.Furthermore,the capability of guiding directional bone growth for the CL scaffolds was demonstrated by a special half-embedded femoral defects model in rabbits.The new bone tissue could consecutively grow into the protruded part of the scaffolds along the spiral cavities.This work provides a promising strategy to construct biomimetic biomaterials for guiding directional bone tissue growth,which offers a new treatment concept for severe bone defects,and even limb regeneration.展开更多
基金National Natural Science Foundation of China[Grant Numbers 81802174,81900726&82072456]Department of Science and Technology of Jilin Province,P.R.C[Grant Numbers 20200404202YY,20200403086SF&20200201453JC]+8 种基金Jilin Province Development and Reform Commission,P.R.C[Grant Number 2018C010]Education Department of Jilin Province,P.R.C[GrantNumber JJKH20180106KJ]Administration of Traditional Chinese Medicine of Jilin Province P.R.C[Grant Number 2018115]10th Youth Project of the First Hospital of Jilin University[Grant Number JDYY102019025]Department of Finance in Jilin Province[Grant Number 2019SCZT046]Undergraduate Teaching Reform Research Project of Jilin University[Grant Number 4Z2000610852]Key training plan for outstanding young teachers of Jilin University[Grant Number 419080520253]Bethune plan of Jilin University[Grant Number 470110000692]The major participant is Qing Han.
文摘A novel reconstructive prosthesis was designed with topological optimization(TO)and a lattice structure to enhance biomechanical and biological properties in the proximal tibia.The biomechanical performance was validated through finite element analysis(FEA)and biomechanical tests.The tibia with inhomogeneous material properties was reconstructed according to computed tomography images,and different components were designed to simulate the operation.Minimum compliance TO subject to a volume fraction constraint combined with a graded lattice structure was utilized to redesign the prosthesis.FEA was performed to evaluate the mechanical performances of the tibia and implants after optimization,including stress,micromotion,and strain energy.The results were analyzed by paired-samples t tests,and p<0.05 was considered significant.Biomechanical testing was used to verify the tibial stresses.Compared to the original group(OG),the TO group(TOG)exhibited lower stress on the stem,and the maximum von Mises stresses were 87.2 and 53.1 MPa,respectively,a 39.1%reduction(p<0.05).Conversely,the stress and strain energy on the tibia increased in the TOG.The maximum von Mises stress values were 16.4 MPa in the OG and 22.9 MPa in the TOG with a 39.6%increase(p<0.05),and the maximum SED value was 0.026 MPa in the OG and 0.042 MPa in the TOG,corresponding to an increase of 61.5%(p<0.05).The maximum micromotions in the distal end of the stem were 135μm in the OG and 68μm in the TOG,almost a 50%reduction.The stress curves of the biomechanical test coincided well with the FEA results.The TO approach can effectively reduce the whole weight of the prosthesis and improve the biomechanical environment of the tibia.It could also pave the way for next-generation applications in orthopedics surgery.
文摘With the population aging and an increasing desire for a high quality of life,millions of patients who suffered knee arthropathy have undergone total knee arthroplasty （TKA）.Although the success rate for primary TKA has been quite high,the number of revision surgeries can not be ignored.Bone loss is one of the challenges confronting surgeons who perform revision TKAs as it can impair alignment accuracy and the long-term stability of the implant.Although several options are available for bone loss after TKA--cement,bone grafting,standard augments,and hinged implants--there is no single ideal option available for all patients with a severe bone defect because of the variety and severity of the defects.1 The burgeoning rapid prototyping （RP） technique,which has been used to fabricate components with complex and unique structures,may offer a novel option in these cases.Keywords：rapid prototyping; severe bone defects; knee
基金National Key R&D Program of China,Grant/Award Numbers:2022YFB2403700,2022YFB2403705Natural Science Foundation of Chongqing,Grant/Award Number:CSTB2022NSCQ-MSX1247。
文摘Mechanical vibration defect is the key factor leading to sudden failure of gas-insulated switchgear(GIS)equipment.It is important to realise effective prediction of the me-chanical vibration state development trend of GIS equipment in order to improve its active safety protection level.This paper carried out research on the accurate prediction method and experimental validation of the mechanical vibration state and its defect severity development trend for the GIS equipment.Firstly,the deep and shallow vibration feature parameters for different mechanical defect signals were jointly extracted by time-domain features and deep belief network methods.Secondly,a new prediction model,incorporating the attention mechanism and the bidirectional gated recurrent unit(BiGRU),was constructed with the deep and shallow vibration feature parameters as inputs.Finally,the prediction trend effectiveness was verified based on the real-type GIS mechanical simulation platform and the field operation GIS equipment.Results show that the deep and shallow vibration feature extraction method proposed in this paper can characterise the mechanical defect information more comprehensively.The new prediction method of the vibration state trend based on the attention-BiGRU model shows ideal accuracy,and the predicted vibration state development trend is highly consistent with the actual,with an average absolute error of 0.063.The root mean square error(ERMSE)value of the prediction method is<5%,which reduces the relative error value at least 37% compared with the traditional prediction models.This paper provides a valuable reference for the proactive defence of GIS mechanical failure.
基金This work was supported by the National Key Research and Development Program of China(grant number 2021YFB3800800)the Natural Science Foundation of China(grant numbers 32225028,32130062)+1 种基金Science and Technology Commission of Shanghai Municipality(grant number 21DZ1205600)Shanghai Pilot Program for Basic Research-Chinese Academy of Science,Shanghai Branch(grant number JCYJ-SHFY-2022-003).
文摘Regeneration of severe bone defects remains an enormous challenge in clinic.Developing regenerative scaffolds to directionally guide bone growth is a potential strategy to overcome this hurdle.Conch,an interesting creature widely spreading in ocean,has tough spiral shell that can continuously grow along the spiral direction.Herein,inspired by the physiological features of conches,a conch-like(CL)scaffold based onβ-TCP bioceramic material was successfully prepared for guiding directional bone growth via digital light processing(DLP)-based 3D printing.Benefiting from the spiral structure,the CL scaffolds significantly improved cell adhesion,proliferation and osteogenic differentiation in vitro compared to the conventional 3D scaffolds.Particularly,the spiral structure in the scaffolds could efficiently induce cells to migrate from the bottom to the top of the scaffolds,which was like“cells climbing stairs”.Furthermore,the capability of guiding directional bone growth for the CL scaffolds was demonstrated by a special half-embedded femoral defects model in rabbits.The new bone tissue could consecutively grow into the protruded part of the scaffolds along the spiral cavities.This work provides a promising strategy to construct biomimetic biomaterials for guiding directional bone tissue growth,which offers a new treatment concept for severe bone defects,and even limb regeneration.
