The mechanical properties of limestone such as the stress-strain curve, the variable characteristics of peak strength and the modulus of elasticity of limestone were studied under the action of temperatures ranging fr...The mechanical properties of limestone such as the stress-strain curve, the variable characteristics of peak strength and the modulus of elasticity of limestone were studied under the action of temperatures ranging from room temperature to 800 °C.Our results show that:1) the temperature has not clear effect on the mechanical properties of limestone from room temperature to 600 °C.However, the mechanical properties of limestone deteriorate rapidly when the temperature is above 600 °C.In this case, the peak stress and modulus of elasticity decrease rapidly.When the temperature reaches 800 °C, the entire process, showing the stress-strain curve is displayed indicating an obvious state of plastic-deformation;2) the failure mode of limestone shows the breakdown of tensile strength from room temperature to 600 °C, as well as the compress shearing damage over 600 °C;3) combining our test results with the concept of thermal damage, a thermal damage equation was derived.展开更多
Objective： To evaluate the therapeutic effects and complications of hydroxyapatite （HA） orbital implantation on patients after trauma-related surgeries. Methods ： Retrospective analysis was made from 211 cases （...Objective： To evaluate the therapeutic effects and complications of hydroxyapatite （HA） orbital implantation on patients after trauma-related surgeries. Methods ： Retrospective analysis was made from 211 cases （211 eyes ） who underwent HA orbital implant placement after trauma-related enucleation or evisceration, including 68 cases of evisceration and primary HA implant placement, 77 cases of enucleation and HA implant placement wrapped with multi-windowed sclera, 66 cases of enucleation and HA implant placement free of wrapping. All the cases were followed up for 1-5 years to observe the therapeutic effects and major complications. Results： Five of 211 cases had wound dehiscence. Ten cases had HA implants exposure, including 1 case suffering severe orbital infection and requiring HA implant removal. The implants exposure incidences by the three surgical methods were from 1.30% to 10.06% and averaged 4.74%. Significant difference was found in late exposure incidence and total incidence from the three methods （ X^2 = 13. 372, P 〈 0.01 and X6^2 = 7. 540, P 〈 0.05 ）. Two cases had shrinkage of the lower fornix. Enophthalmos occurred in 1 case treated by method 1 and was corrected by implanting porous polyethylene （Medpor） plate into the bottom of orbit. In 210 cases, the artificial eye moved well and the cosmetic results were satisfactory. Conclusions- Different surgical methods have their own merit and disadvantage. Enucleation and placement of HA implant wrapped with multi-windowed sclera has corroborated fewer complications than others.展开更多
Objective: To explore the method to repair bone defect with bone-morphogenetic-protein loaded hydroxyapatite/collagen-poly(L-lactic acid) composite. Methods: 18 adult beagle dogs were randomly divided into 3 groups. I...Objective: To explore the method to repair bone defect with bone-morphogenetic-protein loaded hydroxyapatite/collagen-poly(L-lactic acid) composite. Methods: 18 adult beagle dogs were randomly divided into 3 groups. In Group A, bone-morphogenetic-protein (BMP) loaded hydroxyapatite/collagen-poly(L-lactic acid) (HAC-PLA) scaffold was implanted in a 2 cm diaphyseal defect in the radius. In Group B, unloaded pure HAC-PLA scaffold was implanted in the defects. No material was implanted in Group C (control group). The dogs were sacrificed 6 months postoperatively. Features of biocompatibility, biodegradability and osteoinduction were evaluated with histological, radiological examinations and bone mineral density (BMD) measurements. Results: In Group A, the radius defect healed after the treatment with BMP loaded HAC-PLA. BMD at the site of the defect was higher than that of the contralateral radius. Fibrous union developed in the animals of the control group. Conclusions: BMP not only promotes osteogenesis but also accelerates degradation of the biomaterials. Optimized design parameters of a three-dimensional porous biomaterial would give full scope to the role of BMP as an osteoinductive growth factor.展开更多
基金Projects 50490273 supported by the National Natural Science Foundation of China2007CB209400 by the National Basic Research Program of China+1 种基金08KJD130003 by the Basic Research Program of University in Jiangsu ProvinceXKY2007219 by Xuzhou Institute of Technology
文摘The mechanical properties of limestone such as the stress-strain curve, the variable characteristics of peak strength and the modulus of elasticity of limestone were studied under the action of temperatures ranging from room temperature to 800 °C.Our results show that:1) the temperature has not clear effect on the mechanical properties of limestone from room temperature to 600 °C.However, the mechanical properties of limestone deteriorate rapidly when the temperature is above 600 °C.In this case, the peak stress and modulus of elasticity decrease rapidly.When the temperature reaches 800 °C, the entire process, showing the stress-strain curve is displayed indicating an obvious state of plastic-deformation;2) the failure mode of limestone shows the breakdown of tensile strength from room temperature to 600 °C, as well as the compress shearing damage over 600 °C;3) combining our test results with the concept of thermal damage, a thermal damage equation was derived.
文摘Objective： To evaluate the therapeutic effects and complications of hydroxyapatite （HA） orbital implantation on patients after trauma-related surgeries. Methods ： Retrospective analysis was made from 211 cases （211 eyes ） who underwent HA orbital implant placement after trauma-related enucleation or evisceration, including 68 cases of evisceration and primary HA implant placement, 77 cases of enucleation and HA implant placement wrapped with multi-windowed sclera, 66 cases of enucleation and HA implant placement free of wrapping. All the cases were followed up for 1-5 years to observe the therapeutic effects and major complications. Results： Five of 211 cases had wound dehiscence. Ten cases had HA implants exposure, including 1 case suffering severe orbital infection and requiring HA implant removal. The implants exposure incidences by the three surgical methods were from 1.30% to 10.06% and averaged 4.74%. Significant difference was found in late exposure incidence and total incidence from the three methods （ X^2 = 13. 372, P 〈 0.01 and X6^2 = 7. 540, P 〈 0.05 ）. Two cases had shrinkage of the lower fornix. Enophthalmos occurred in 1 case treated by method 1 and was corrected by implanting porous polyethylene （Medpor） plate into the bottom of orbit. In 210 cases, the artificial eye moved well and the cosmetic results were satisfactory. Conclusions- Different surgical methods have their own merit and disadvantage. Enucleation and placement of HA implant wrapped with multi-windowed sclera has corroborated fewer complications than others.
文摘Objective: To explore the method to repair bone defect with bone-morphogenetic-protein loaded hydroxyapatite/collagen-poly(L-lactic acid) composite. Methods: 18 adult beagle dogs were randomly divided into 3 groups. In Group A, bone-morphogenetic-protein (BMP) loaded hydroxyapatite/collagen-poly(L-lactic acid) (HAC-PLA) scaffold was implanted in a 2 cm diaphyseal defect in the radius. In Group B, unloaded pure HAC-PLA scaffold was implanted in the defects. No material was implanted in Group C (control group). The dogs were sacrificed 6 months postoperatively. Features of biocompatibility, biodegradability and osteoinduction were evaluated with histological, radiological examinations and bone mineral density (BMD) measurements. Results: In Group A, the radius defect healed after the treatment with BMP loaded HAC-PLA. BMD at the site of the defect was higher than that of the contralateral radius. Fibrous union developed in the animals of the control group. Conclusions: BMP not only promotes osteogenesis but also accelerates degradation of the biomaterials. Optimized design parameters of a three-dimensional porous biomaterial would give full scope to the role of BMP as an osteoinductive growth factor.
