We present a new cyclometalated Ir（III） complexes IrBDP, which could self-assemble into organic nanoparticles （IrBDP NPs）. IrBDP NPs show enhanced photodynamic effect and can be engulfed by HeLa cells for cell ima...We present a new cyclometalated Ir（III） complexes IrBDP, which could self-assemble into organic nanoparticles （IrBDP NPs）. IrBDP NPs show enhanced photodynamic effect and can be engulfed by HeLa cells for cell imaging as well as photodynamic therapy （PDT） upon low energy irradiation.展开更多
To further enhance the transfection efficiency of a micelleplex system based on monomethoxy poly（ethylene glycol）-block-poly（e-caprolactone）-block-poly（L-lysine） （MPEG-b-PCL-b-PLL）, cholesterol （Chol） moieti...To further enhance the transfection efficiency of a micelleplex system based on monomethoxy poly（ethylene glycol）-block-poly（e-caprolactone）-block-poly（L-lysine） （MPEG-b-PCL-b-PLL）, cholesterol （Chol） moieties are attached to the e-termini of PLL segments to obtain MPEG-b-PCL-b-PLL/Chol. The structure and morphology of the copolymer are studied by IH-NMR, TEM and DLS （dynamic light scattering）. The cytotoxicity, cell uptake, endosomal release and mRNA knockdown are studied by MTT （3-[4,5-dimethylthiazol-2-yl]-2,5-diphenyltetrazolium bromide） assay, flow cytometry, CLSM （confocal laser scanning microscopy） and RT-PCR （real-time polymerase chain reaction）. The results show that compared to their precursor MPEG-b-PCL-b-PLL, the cholesterol-grafted copolymer shows significantly lower toxicity, more rapid cellular endocytosis and endosome escape, and consequently displays enhanced siRNA transfection efficiency even at a lower N/P ratio. These improvements are ascribed to enhanced interaction of the cholesterol moieties with both cellular membrane and endosomal membrane. Moreover, effect of the PLL block length is examined. The final conclusion is that long enough PLL segments and incorporation of proper fraction of cholesterol onto the PLL segments benefit the enhancement of siRNA transfection efficiency.展开更多
The lower head of reactor pressure vessel （RPV） will endure a great temperature gradient above the phase transition temperature, and the creep and fracture will be the primary failure mode for the RPV material in su...The lower head of reactor pressure vessel （RPV） will endure a great temperature gradient above the phase transition temperature, and the creep and fracture will be the primary failure mode for the RPV material in such a situation. The interrupted creep tests were performed on a typical RPV material, SA508 Gr3 steel, at 800 ℃. The microstructure of different creep stages was examined by scanning electron microscopy and transmission electron microscopy. The results showed that the microscopic damage is mainly induced by creep cavities and coarse second-phase particles. Furthermore, the volume fractions of creep cavities and coarse second-phase particles show a linear relationship with the extended creep time. The second-phase particles are determined to be MoC in the second creep stage and Mo2C in the third creep stage, according to the results of selected-area electron diffraction pattern. Combined with energy-dispersive spectrum analysis, the segregation of precipitates caused by the migration of atoms is finally unveiled, which leads to the coarsening of the particles.展开更多
基金financially supported by the National Natural Science Foundation of China(Nos.21474012 and 21504089)
文摘We present a new cyclometalated Ir（III） complexes IrBDP, which could self-assemble into organic nanoparticles （IrBDP NPs）. IrBDP NPs show enhanced photodynamic effect and can be engulfed by HeLa cells for cell imaging as well as photodynamic therapy （PDT） upon low energy irradiation.
基金supported by the National Natural Science Foundation of China (No. 21004062)"100 Talents Program" of the Chinese Academy of Sciences (No. KGCX2-YW-802)the Ministry of Science and Technology ofChina ("973 Project", No. 2009CB930102)
文摘To further enhance the transfection efficiency of a micelleplex system based on monomethoxy poly（ethylene glycol）-block-poly（e-caprolactone）-block-poly（L-lysine） （MPEG-b-PCL-b-PLL）, cholesterol （Chol） moieties are attached to the e-termini of PLL segments to obtain MPEG-b-PCL-b-PLL/Chol. The structure and morphology of the copolymer are studied by IH-NMR, TEM and DLS （dynamic light scattering）. The cytotoxicity, cell uptake, endosomal release and mRNA knockdown are studied by MTT （3-[4,5-dimethylthiazol-2-yl]-2,5-diphenyltetrazolium bromide） assay, flow cytometry, CLSM （confocal laser scanning microscopy） and RT-PCR （real-time polymerase chain reaction）. The results show that compared to their precursor MPEG-b-PCL-b-PLL, the cholesterol-grafted copolymer shows significantly lower toxicity, more rapid cellular endocytosis and endosome escape, and consequently displays enhanced siRNA transfection efficiency even at a lower N/P ratio. These improvements are ascribed to enhanced interaction of the cholesterol moieties with both cellular membrane and endosomal membrane. Moreover, effect of the PLL block length is examined. The final conclusion is that long enough PLL segments and incorporation of proper fraction of cholesterol onto the PLL segments benefit the enhancement of siRNA transfection efficiency.
基金This research was supported by the National Natural Science Foundation of China （51575489） and National 13th Five-Year Key Technologies R＆D Program （No. 2016YFC0801902）.
文摘The lower head of reactor pressure vessel （RPV） will endure a great temperature gradient above the phase transition temperature, and the creep and fracture will be the primary failure mode for the RPV material in such a situation. The interrupted creep tests were performed on a typical RPV material, SA508 Gr3 steel, at 800 ℃. The microstructure of different creep stages was examined by scanning electron microscopy and transmission electron microscopy. The results showed that the microscopic damage is mainly induced by creep cavities and coarse second-phase particles. Furthermore, the volume fractions of creep cavities and coarse second-phase particles show a linear relationship with the extended creep time. The second-phase particles are determined to be MoC in the second creep stage and Mo2C in the third creep stage, according to the results of selected-area electron diffraction pattern. Combined with energy-dispersive spectrum analysis, the segregation of precipitates caused by the migration of atoms is finally unveiled, which leads to the coarsening of the particles.
