Fe3O4 magnetic nanoparticles were prepared by the aqueous co-precipitation of FeCl3-6H2O and FeCl2-4H2O with addition of ammonium hydroxide. The conditions for the preparation of Fe3O4 magnetic nanoparticles were opti...Fe3O4 magnetic nanoparticles were prepared by the aqueous co-precipitation of FeCl3-6H2O and FeCl2-4H2O with addition of ammonium hydroxide. The conditions for the preparation of Fe3O4 magnetic nanoparticles were optimized, and Fe3O4 magnetic nanoparticles obtained were characterized systematically by means of transmission electron microscope （TEM）, dynamic laser scattering analyzer （DLS） and X-ray diffraction （XRD）. The results revealed that the magnetic nanoparticles were cubic shaped and dispersive, with narrow size distribution and average diameter of 11.4 nm. It was found that the homogeneous variation of pH value in the solution via the control on the dropping rate of aqueous ammonia played a critical role in size distribution. The magnetic response of the product in the magnetic field was also analyzed and evaluated carefully. A 32.6 mT magnetic field which is produced by four ferromagnets was found to be sufficient to excite the dipole moments of 0.05 g Fe3O4 powder 2 cm far away from the ferromagnets. In conclusion, the Fe3O4 magnetic nanoparticles with excellent properties were competent for the magnetic carders of targeted-drug in future application.展开更多
Stress analysis of cylindrical grid-stiffened composite shells was conducted under transverse loading,pure bending,torsion and axial compression under clamped-free boundary condition.Electrical strain gauges were empl...Stress analysis of cylindrical grid-stiffened composite shells was conducted under transverse loading,pure bending,torsion and axial compression under clamped-free boundary condition.Electrical strain gauges were employed to measure the strains in transverse loading case to validate the finite element analysis which was conducted using ANSYS software.Good agreement was obtained between the two methods.It was observed that stiffening the composite shell with helical ribs decreased the average equivalent Von Mises stress on the shell.The reduction of the stress seemed to be higher in the intersection of two ribs.It was also seen that the stress reduction ratio was higher when the structure was under bending compared to torsion and axial compression.The reduction ratio was approximately 75% in pure bending in the intersection point of the ribs,while it was approximately 25% in torsion.Therefore,it is concluded that the presence of the ribs is more effective under bending.Failure analysis was done using Tsai-Wu criterion.The ribs were observed to result in maximum and minimum increase in the failure load of the structure under transverse bending and torsional loading,respectively.展开更多
To reduce the problems of poor solubility,high in vivo dosage requirement,and weak targeting ability of paclitaxel(PTX),a hyaluronic acid-octadecylamine(HA-ODA)-modified nano-structured lipid carrier(HA-NLC)was constr...To reduce the problems of poor solubility,high in vivo dosage requirement,and weak targeting ability of paclitaxel(PTX),a hyaluronic acid-octadecylamine(HA-ODA)-modified nano-structured lipid carrier(HA-NLC)was constructed.HA-ODA conjugates were synthesized by an amide reaction between HA and ODA.The hydrophobic chain of HA-ODA can be embedded in the lipid core of the NLC to obtain HA-NLC.The HA-NLC displayed strong internalization in cluster determinant 44(CD44)highly expressed MCF-7 cells,and endocytosis mediated by the CD44 receptor was involved.The HA-NLC had an encapsulation efficiency of PTX of 72.0%.The cytotoxicity of the PTXloaded nanoparticle HA-NLC/PTX in MCF-7 cells was much stronger than that of the commercial preparation Taxol.In vivo,the HA-NLC exhibited strong tumor targeting ability.The distribution of the NLCs to the liver and spleen was reduced after HA modification,while more nanoparticles were aggregated to the tumor site.Our results suggest that HA-NLC has excellent properties as a nano drug carrier and potential for in vivo targeting.展开更多
基金the Technology Project of Jiangxi Provincial Education DepartmentJiangxi Provincial Science Department
文摘Fe3O4 magnetic nanoparticles were prepared by the aqueous co-precipitation of FeCl3-6H2O and FeCl2-4H2O with addition of ammonium hydroxide. The conditions for the preparation of Fe3O4 magnetic nanoparticles were optimized, and Fe3O4 magnetic nanoparticles obtained were characterized systematically by means of transmission electron microscope （TEM）, dynamic laser scattering analyzer （DLS） and X-ray diffraction （XRD）. The results revealed that the magnetic nanoparticles were cubic shaped and dispersive, with narrow size distribution and average diameter of 11.4 nm. It was found that the homogeneous variation of pH value in the solution via the control on the dropping rate of aqueous ammonia played a critical role in size distribution. The magnetic response of the product in the magnetic field was also analyzed and evaluated carefully. A 32.6 mT magnetic field which is produced by four ferromagnets was found to be sufficient to excite the dipole moments of 0.05 g Fe3O4 powder 2 cm far away from the ferromagnets. In conclusion, the Fe3O4 magnetic nanoparticles with excellent properties were competent for the magnetic carders of targeted-drug in future application.
文摘Stress analysis of cylindrical grid-stiffened composite shells was conducted under transverse loading,pure bending,torsion and axial compression under clamped-free boundary condition.Electrical strain gauges were employed to measure the strains in transverse loading case to validate the finite element analysis which was conducted using ANSYS software.Good agreement was obtained between the two methods.It was observed that stiffening the composite shell with helical ribs decreased the average equivalent Von Mises stress on the shell.The reduction of the stress seemed to be higher in the intersection of two ribs.It was also seen that the stress reduction ratio was higher when the structure was under bending compared to torsion and axial compression.The reduction ratio was approximately 75% in pure bending in the intersection point of the ribs,while it was approximately 25% in torsion.Therefore,it is concluded that the presence of the ribs is more effective under bending.Failure analysis was done using Tsai-Wu criterion.The ribs were observed to result in maximum and minimum increase in the failure load of the structure under transverse bending and torsional loading,respectively.
基金Project supported by the Zhejiang Provincial Natural Science Foundation of China(No.LY14H160016)。
文摘To reduce the problems of poor solubility,high in vivo dosage requirement,and weak targeting ability of paclitaxel(PTX),a hyaluronic acid-octadecylamine(HA-ODA)-modified nano-structured lipid carrier(HA-NLC)was constructed.HA-ODA conjugates were synthesized by an amide reaction between HA and ODA.The hydrophobic chain of HA-ODA can be embedded in the lipid core of the NLC to obtain HA-NLC.The HA-NLC displayed strong internalization in cluster determinant 44(CD44)highly expressed MCF-7 cells,and endocytosis mediated by the CD44 receptor was involved.The HA-NLC had an encapsulation efficiency of PTX of 72.0%.The cytotoxicity of the PTXloaded nanoparticle HA-NLC/PTX in MCF-7 cells was much stronger than that of the commercial preparation Taxol.In vivo,the HA-NLC exhibited strong tumor targeting ability.The distribution of the NLCs to the liver and spleen was reduced after HA modification,while more nanoparticles were aggregated to the tumor site.Our results suggest that HA-NLC has excellent properties as a nano drug carrier and potential for in vivo targeting.
