In this paper three important characteristics in piezoresistance for the orthotropic material are given and proved theoretically:(1) The piezoresistance on the principal axis of an orthotropic material is independent ...In this paper three important characteristics in piezoresistance for the orthotropic material are given and proved theoretically:(1) The piezoresistance on the principal axis of an orthotropic material is independent of shear strains/stresses, but correlated with the normal strains/stresses only;(2) On the principal axis of material, following relations between piezoconductivity and piezoresistivity exist η iikk =-(γ ii ) -2 ξ iikk =-(ρ ii ) 2ξ iikk λ iikk =-(γ ii ) -2 χ iikk =-(ρ ii ) 2χ iikk (3) A laminate composed of orthotropic laminae in different orientations is orthotropic for its average/effective properties.展开更多
1 Results A new type of hybrid materails prepared from ternary systems polymer/bicopper organic complex/solvent is presented.Each binary system displays differing types of behaviour: The polymer solutions produce ther...1 Results A new type of hybrid materails prepared from ternary systems polymer/bicopper organic complex/solvent is presented.Each binary system displays differing types of behaviour: The polymer solutions produce thermoreversible gels while the bicopper organic complex (designated as CuS8) forms randomly-dispersed,self-assembling threads in organic solvents (See Fig.1(a),(b)).Fig.1 The CuS8 and ips thermoreversible gels Thermoreversible gels possess a fibrillar morphology with a typical mesh size ra...展开更多
This study aimed to utilize micro-computed tomography （micro-CT） analysis to compare new bone formation in rat calvarial defects using chitosan/fibroin-hydroxyapatite （CFB-HAP） or collagen （Bio-Gide） membranes. ...This study aimed to utilize micro-computed tomography （micro-CT） analysis to compare new bone formation in rat calvarial defects using chitosan/fibroin-hydroxyapatite （CFB-HAP） or collagen （Bio-Gide） membranes. Fifty-four （54） rats were studied. A circular bony defect （8 mm diameter） was formed in the centre of the calvaria using a trephine bur. The CFB-HAP membrane was prepared by thermally induced phase separation. In the experimental group （n= 18）, the CFB-HAP membrane was used to cover the bony defect, and in the control group （n= 18）, a resorbable collagen membrane （Bio-Gide） was used. In the negative control group （n= 18）, no membrane was used. In each group, six animals were euthanized at 2, 4 and 8 weeks after surgery. The specimens were then analysed using micro-CT. There were significant differences in bone volume （BV） and bone mineral density （BMD） （P〈O.05） between the negative control group and the membrane groups. However, there were no significant differences between the CFB-HAP group and the collagen group. We concluded that the CFB-HAP membrane has significant potential as a guided bone regeneration （GBR） membrane.展开更多
Infection and insufficient osteointegration are the main causes of orthopedic implant failure.Furthermore,activating favorable inflammation response is vital to the fast osteointegration of implants.Therefore,endowing...Infection and insufficient osteointegration are the main causes of orthopedic implant failure.Furthermore,activating favorable inflammation response is vital to the fast osteointegration of implants.Therefore,endowing the implants with multifunctions(antibacterial,anti-inflammation,and pro-osteointegration)is a promising strategy to improve the performance of orthopedic implants.In this study,a Zn-contained polydopamine(PDA)film was fabricated on AZ31 alloy.The film possessed a stable Zn ion release in 14 days.The results of electrochemical analysis implied the favorable corrosion protection of the film,and thus,leading to a suitable hemolysis ratio(below 1%).The in vitro antibacterial assessment revealed that the film exhibited excellent resistance against Staphylococcus aureus(nearly 100%),which can be ascribed to the release of Zn ions.The cell-culture evaluation revealed that the extract of Zn-contained PDA-coated sample can activate RAW264.7 polarization to an anti-inflammatory phenotype,as well as enhance the osteogenic dif-ferentiation ability of MC3T3-E 1.Additionally,the femoral osteomyelitis model indicated that the as-prepared film had a high antibacterial capability at early stage of the implantation,and showed better osteogenesis and osteointegration after 8 weeks of implantation.With favorable antibacte-rial,anti-inflammation,and pro-osteogenesis abilities,the novel designed Zn-contained PDA film is promising to be used in Mg-based orthopedic implants.展开更多
文摘In this paper three important characteristics in piezoresistance for the orthotropic material are given and proved theoretically:(1) The piezoresistance on the principal axis of an orthotropic material is independent of shear strains/stresses, but correlated with the normal strains/stresses only;(2) On the principal axis of material, following relations between piezoconductivity and piezoresistivity exist η iikk =-(γ ii ) -2 ξ iikk =-(ρ ii ) 2ξ iikk λ iikk =-(γ ii ) -2 χ iikk =-(ρ ii ) 2χ iikk (3) A laminate composed of orthotropic laminae in different orientations is orthotropic for its average/effective properties.
文摘1 Results A new type of hybrid materails prepared from ternary systems polymer/bicopper organic complex/solvent is presented.Each binary system displays differing types of behaviour: The polymer solutions produce thermoreversible gels while the bicopper organic complex (designated as CuS8) forms randomly-dispersed,self-assembling threads in organic solvents (See Fig.1(a),(b)).Fig.1 The CuS8 and ips thermoreversible gels Thermoreversible gels possess a fibrillar morphology with a typical mesh size ra...
文摘This study aimed to utilize micro-computed tomography （micro-CT） analysis to compare new bone formation in rat calvarial defects using chitosan/fibroin-hydroxyapatite （CFB-HAP） or collagen （Bio-Gide） membranes. Fifty-four （54） rats were studied. A circular bony defect （8 mm diameter） was formed in the centre of the calvaria using a trephine bur. The CFB-HAP membrane was prepared by thermally induced phase separation. In the experimental group （n= 18）, the CFB-HAP membrane was used to cover the bony defect, and in the control group （n= 18）, a resorbable collagen membrane （Bio-Gide） was used. In the negative control group （n= 18）, no membrane was used. In each group, six animals were euthanized at 2, 4 and 8 weeks after surgery. The specimens were then analysed using micro-CT. There were significant differences in bone volume （BV） and bone mineral density （BMD） （P〈O.05） between the negative control group and the membrane groups. However, there were no significant differences between the CFB-HAP group and the collagen group. We concluded that the CFB-HAP membrane has significant potential as a guided bone regeneration （GBR） membrane.
基金This study was supported by the National Key Research and Development Project(2017YFB0702600,2016YFB0700800)China Postdoctoral Science Foundation(2019M662830)+3 种基金National Natural Science Foundation of China(51901239)Natural Science Foundation of Guangdong Province,China(Grant No.2020A1515011447)The Joint Fund of Ministry of Education for Equipment Pre-research(No.6141A02022632)Scientific and Technological Projects of Guangzhou,China(Grant No.202002030283).
文摘Infection and insufficient osteointegration are the main causes of orthopedic implant failure.Furthermore,activating favorable inflammation response is vital to the fast osteointegration of implants.Therefore,endowing the implants with multifunctions(antibacterial,anti-inflammation,and pro-osteointegration)is a promising strategy to improve the performance of orthopedic implants.In this study,a Zn-contained polydopamine(PDA)film was fabricated on AZ31 alloy.The film possessed a stable Zn ion release in 14 days.The results of electrochemical analysis implied the favorable corrosion protection of the film,and thus,leading to a suitable hemolysis ratio(below 1%).The in vitro antibacterial assessment revealed that the film exhibited excellent resistance against Staphylococcus aureus(nearly 100%),which can be ascribed to the release of Zn ions.The cell-culture evaluation revealed that the extract of Zn-contained PDA-coated sample can activate RAW264.7 polarization to an anti-inflammatory phenotype,as well as enhance the osteogenic dif-ferentiation ability of MC3T3-E 1.Additionally,the femoral osteomyelitis model indicated that the as-prepared film had a high antibacterial capability at early stage of the implantation,and showed better osteogenesis and osteointegration after 8 weeks of implantation.With favorable antibacte-rial,anti-inflammation,and pro-osteogenesis abilities,the novel designed Zn-contained PDA film is promising to be used in Mg-based orthopedic implants.
