The spark plasma sintering（SPS） method was used to study the mechanism of reaction interface between Zr and Ti3AlC2 with electric current going through it. It was found that electric current greatly reduced the bond...The spark plasma sintering（SPS） method was used to study the mechanism of reaction interface between Zr and Ti3AlC2 with electric current going through it. It was found that electric current greatly reduced the bonding temperature of Zr and Ti3AlC2. By the micro-structure analysis of the interface through SEM/EDS, it was found that Al atoms diffused from the Ti3AlC2 substrate into the Zr side and reacted with Zr to form the Zr-Al compounds at the interface, which is the strengthening mechanism of Ti3AlC2-Zr bonding. The thickness of reaction layers（Zr-Al alloy） was from 0.879 to 13.945 mm depending on different sintering condition. Current direction, heating rate, soaking time, pulse patterns all influenced the diffusion of Al atoms which affected the joining quality of Zr and Ti3AlC2.展开更多
Porous microstructures on Nickel-Titanium (NiTi) alloy surfaces were prepared by linearly polarized femtosecond lasers with moving focal point at a certain speed. It was found that various novel micro-structures from ...Porous microstructures on Nickel-Titanium (NiTi) alloy surfaces were prepared by linearly polarized femtosecond lasers with moving focal point at a certain speed. It was found that various novel micro-structures from feather-like ripples to cluster-like porous textures could be formed with increasing laser energy. Particularly, when the laser energy was 400 μJ, a periodic porous metal surface was gen-erated. Measurement of X-ray diffraction showed that the grains on the sample surface were refined through femtosecond laser ablation processes, but the crystal structures still kept their original states. Analysis by X-ray photoelectron spectroscopy revealed that Ni/Ti on the sample surface was changed with an evident oxidization of titanium element under different laser energies. This investigation pro-vides a new approach to improve the biocompatibility of NiTi-based implant devices.展开更多
Biological safety and stable sustained-release of the drug are two crucial issues involved in the formulation of paclitaxel.Focusing on these issues, by using the FDA approved polylactide as carrier material, soybean ...Biological safety and stable sustained-release of the drug are two crucial issues involved in the formulation of paclitaxel.Focusing on these issues, by using the FDA approved polylactide as carrier material, soybean lecithin as surfactant and maltodextrin as thickener, paclitaxel loaded PLA microspheres were simply prepared by solvent evaporation, thus guaranteeing the biological safety. The introduction of maltodextrin as a thickener aided to a stable sustained-release of paclitaxel. Surface morphology, particle size, drug loading rate, encapsulation efficiency and in vitro drug release behavior were investigated.Biological safety evaluations such as acute toxicity, allergies, hemolysis, skin stimulation and genotoxicity test were also carried out. Results showed that the obtained microspheres were biocompatible and could release paclitaxel at a desirable constant rate.Therefore, the simply prepared paclitaxel formulation with good biological safety and desirable release behavior exhibited great potential of local injection of paclitaxel for the clinical use in the future.展开更多
基金Supported by National Natural Science Foundation of China(Nos.91226202,91426304)CAS Interdisciplinary Innovation Team Project
文摘The spark plasma sintering（SPS） method was used to study the mechanism of reaction interface between Zr and Ti3AlC2 with electric current going through it. It was found that electric current greatly reduced the bonding temperature of Zr and Ti3AlC2. By the micro-structure analysis of the interface through SEM/EDS, it was found that Al atoms diffused from the Ti3AlC2 substrate into the Zr side and reacted with Zr to form the Zr-Al compounds at the interface, which is the strengthening mechanism of Ti3AlC2-Zr bonding. The thickness of reaction layers（Zr-Al alloy） was from 0.879 to 13.945 mm depending on different sintering condition. Current direction, heating rate, soaking time, pulse patterns all influenced the diffusion of Al atoms which affected the joining quality of Zr and Ti3AlC2.
基金Supported by the National Natural Science Foundation of China (Project No. 50471048)Specialized Research Fund for the Doctoral Program of Higher Education of China (Project No. 20040056016)
文摘Porous microstructures on Nickel-Titanium (NiTi) alloy surfaces were prepared by linearly polarized femtosecond lasers with moving focal point at a certain speed. It was found that various novel micro-structures from feather-like ripples to cluster-like porous textures could be formed with increasing laser energy. Particularly, when the laser energy was 400 μJ, a periodic porous metal surface was gen-erated. Measurement of X-ray diffraction showed that the grains on the sample surface were refined through femtosecond laser ablation processes, but the crystal structures still kept their original states. Analysis by X-ray photoelectron spectroscopy revealed that Ni/Ti on the sample surface was changed with an evident oxidization of titanium element under different laser energies. This investigation pro-vides a new approach to improve the biocompatibility of NiTi-based implant devices.
基金supported by the National Natural Science Foundation of China(Grant Nos.51073118,51473119)
文摘Biological safety and stable sustained-release of the drug are two crucial issues involved in the formulation of paclitaxel.Focusing on these issues, by using the FDA approved polylactide as carrier material, soybean lecithin as surfactant and maltodextrin as thickener, paclitaxel loaded PLA microspheres were simply prepared by solvent evaporation, thus guaranteeing the biological safety. The introduction of maltodextrin as a thickener aided to a stable sustained-release of paclitaxel. Surface morphology, particle size, drug loading rate, encapsulation efficiency and in vitro drug release behavior were investigated.Biological safety evaluations such as acute toxicity, allergies, hemolysis, skin stimulation and genotoxicity test were also carried out. Results showed that the obtained microspheres were biocompatible and could release paclitaxel at a desirable constant rate.Therefore, the simply prepared paclitaxel formulation with good biological safety and desirable release behavior exhibited great potential of local injection of paclitaxel for the clinical use in the future.
