Irregular craniofacial bone defects caused by craniofacial fractures always result in craniofacial bone and contour asymmetry and should therefore be reconstructed.Polyetheretherketone(PEEK)is an ideal substitute for ...Irregular craniofacial bone defects caused by craniofacial fractures always result in craniofacial bone and contour asymmetry and should therefore be reconstructed.Polyetheretherketone(PEEK)is an ideal substitute for autologous bone grafts and has been widely used in craniofacial bone defect reconstruction.The precise design of custom-made PEEK implants is particularly important to optimise reconstruction.Herein,the workflow and principles for the design and manufacture of PEEK implants are summarised,and a protocol for the precise design of an irregular craniofacial bone defect PEEK implant is presented.According to the method and principles,the design flow was efficient and could be standardised,and design errors could be avoided as much as possible.展开更多
Irregular bone defects,characterized by unpredictable size,shape,and depth,pose a major challenge to clinical treatment.Although various bone grafts are available,none can fully meet the repair needs of the defective ...Irregular bone defects,characterized by unpredictable size,shape,and depth,pose a major challenge to clinical treatment.Although various bone grafts are available,none can fully meet the repair needs of the defective area.Here,this study fabricates a dough-type hydrogel(DR-Net),in which the first dynamic network is generated by coordination between thiol groups and silver ions,thereby possessing kneadability to adapt to various irregular bone defects.The second rigid covalent network is formed through photocrosslinking,maintaining the osteogenic space under external forces and achieving a better match with the bone regeneration process.In vitro,an irregular alveolar bone defect is established in the fresh porcine mandible,and the dough-type hydrogel exhibits outstanding shape adaptability,perfectly matching the morphology of the bone defect.After photocuring,the storage modulus of the hydrogel increases 8.6 times,from 3.7 kPa(before irradiation)to 32 kPa(after irradiation).Furthermore,this hydrogel enables effective loading of P24 peptide,which potently accelerates bone repair in Sprague–Dawley(SD)rats with critical calvarial defects.Overall,the dough-type hydrogel with kneadability,space-maintaining capability,and osteogenic activity exhibits exceptional potential for clinical translation in treating irregular bone defects.展开更多
In gear dynamics,time-varying mesh stiffness represents a primary internal excitation source,as recognized by numerous scholars.The accurate calculation of mesh stiffness holds significant importance for analyzing vib...In gear dynamics,time-varying mesh stiffness represents a primary internal excitation source,as recognized by numerous scholars.The accurate calculation of mesh stiffness holds significant importance for analyzing vibration in helical gear systems.During operational conditions,spalling defects emerge due to wear,affecting the tooth surface contact state and causing mesh stiffness fluctuations.Therefore,establishing an analytical model for calculating timevarying mesh excitation under defective tooth surface conditions becomes essential.This paper employs tooth surface contact projection analysis to obtain helical gear tooth surface contact lines by simulating actual threedimensional rotation angles and contact relationships.Based on this analysis,the principle of potential energy superposition is utilized to propose a method for calculating helical gear pair mesh stiffness,incorporating the effects of gear base and transition curves.In modeling mesh stiffness with irregular spalling defects,regional methods correct changes in moment of inertia and crosssectional area of variable-section cantilever beams caused by defects,effectively describing the impact of irregular defects on time-varying mesh stiffness.Finally,a finite element method validates the analytical calculations through a contact model of gear pairs with defects.展开更多
基金the Program of Shanghai Municipal Commission of Health and Family Planning(No.20194Y0033)。
文摘Irregular craniofacial bone defects caused by craniofacial fractures always result in craniofacial bone and contour asymmetry and should therefore be reconstructed.Polyetheretherketone(PEEK)is an ideal substitute for autologous bone grafts and has been widely used in craniofacial bone defect reconstruction.The precise design of custom-made PEEK implants is particularly important to optimise reconstruction.Herein,the workflow and principles for the design and manufacture of PEEK implants are summarised,and a protocol for the precise design of an irregular craniofacial bone defect PEEK implant is presented.According to the method and principles,the design flow was efficient and could be standardised,and design errors could be avoided as much as possible.
基金supported by the National Natural Science Foundation of China(82071104/32101104/82202663)Science and Technology Commission of Shanghai Municipality(23XD1434200/22Y21901000)+2 种基金Program of Shanghai Academic/Technology Research Leader(22XD1422600)Shanghai Municipal Health Planning Commission(202140127)Shanghai Hospital Development Center(SHDC12022120).
文摘Irregular bone defects,characterized by unpredictable size,shape,and depth,pose a major challenge to clinical treatment.Although various bone grafts are available,none can fully meet the repair needs of the defective area.Here,this study fabricates a dough-type hydrogel(DR-Net),in which the first dynamic network is generated by coordination between thiol groups and silver ions,thereby possessing kneadability to adapt to various irregular bone defects.The second rigid covalent network is formed through photocrosslinking,maintaining the osteogenic space under external forces and achieving a better match with the bone regeneration process.In vitro,an irregular alveolar bone defect is established in the fresh porcine mandible,and the dough-type hydrogel exhibits outstanding shape adaptability,perfectly matching the morphology of the bone defect.After photocuring,the storage modulus of the hydrogel increases 8.6 times,from 3.7 kPa(before irradiation)to 32 kPa(after irradiation).Furthermore,this hydrogel enables effective loading of P24 peptide,which potently accelerates bone repair in Sprague–Dawley(SD)rats with critical calvarial defects.Overall,the dough-type hydrogel with kneadability,space-maintaining capability,and osteogenic activity exhibits exceptional potential for clinical translation in treating irregular bone defects.
文摘In gear dynamics,time-varying mesh stiffness represents a primary internal excitation source,as recognized by numerous scholars.The accurate calculation of mesh stiffness holds significant importance for analyzing vibration in helical gear systems.During operational conditions,spalling defects emerge due to wear,affecting the tooth surface contact state and causing mesh stiffness fluctuations.Therefore,establishing an analytical model for calculating timevarying mesh excitation under defective tooth surface conditions becomes essential.This paper employs tooth surface contact projection analysis to obtain helical gear tooth surface contact lines by simulating actual threedimensional rotation angles and contact relationships.Based on this analysis,the principle of potential energy superposition is utilized to propose a method for calculating helical gear pair mesh stiffness,incorporating the effects of gear base and transition curves.In modeling mesh stiffness with irregular spalling defects,regional methods correct changes in moment of inertia and crosssectional area of variable-section cantilever beams caused by defects,effectively describing the impact of irregular defects on time-varying mesh stiffness.Finally,a finite element method validates the analytical calculations through a contact model of gear pairs with defects.
