AIM To compare the effects of liposomes andglyco-poly-L-lysine on liver targeted uptake andexpression of plasmid in rat liver.METHODS After binding with lipofectamine orgalactose-terminal glyco-poly-L-lysine,theplasmi...AIM To compare the effects of liposomes andglyco-poly-L-lysine on liver targeted uptake andexpression of plasmid in rat liver.METHODS After binding with lipofectamine orgalactose-terminal glyco-poly-L-lysine,theplasmid could be expressed in eukaryotic cellswhen injected into Wistar rats by intravenousroute.At different time intervals after the injection,the distribution and expression of the plasmid inliver of rats were observed and compared using insitu hybridization and immunohistochemistry.RESULTS The expression of the plasmid bindingto liposomes or G-PLL could be markedly observed24 h later,and began to decrease one week later,but it still could be observed up to three weeks.Both liposomes and G-PLL could deliver theplasmid to the liver effectively,but the effect of thelatter was better than the former concerning thedistribution and expression of the plasmid targeteduptake in the liver.CONCLUSION G-PLL is better than liposome asthe targeted carrier for delivering exogenous genesto the liver.展开更多
In this paper the persistent currents of ideal toroidal single-wall carbon nanotubes (TSWNTs) are calculated from the tight-binding model and the periodic boundary conditions. The electronic structure and persistent c...In this paper the persistent currents of ideal toroidal single-wall carbon nanotubes (TSWNTs) are calculated from the tight-binding model and the periodic boundary conditions. The electronic structure and persistent current of a TSWNT strongly depend on its helicity and longitudinal circumference, making the TSWNTs a geometry-sensitive kind of materials. The interatomic carbonic interactions other than pp pi-type are also studied and are found to introduce more steps to the persistent current. The diamagnetic-paramagnetic transitions occur more frequently, and the persistent current depends on the interaction energy values, while the periodicity of magnetic flux preserves.展开更多
The antiwear properties of two wheel/rail lubricating oils were tested and compared on an Amsler machine. Under same testing conditions, oil A (developed by authors) showed much better wear resistance and higher load-...The antiwear properties of two wheel/rail lubricating oils were tested and compared on an Amsler machine. Under same testing conditions, oil A (developed by authors) showed much better wear resistance and higher load-carrying capacity than oil B (imported from abroad). The X-ray diffraction (XRD) analyses of the worn surfaces showed that different extreme pressure (EP) lubricating films were formed on the surfaces when the rollers were lubricated with different oils under boundary lubrication condition. The EP film of oil A was a composite film containing three compounds, FeO, FeSx and FeP, while oil B formed only a simple EP film of FePO4. The composite EP film showed lower shear strength and better antiwear property than the simple EP film, which brought about different wear resistance df the two wheel/rail lubricating oils.展开更多
In order to reveal the wear mechanism of ceramic cutting tools in real cutting process, a simulation test was carried out on a block-on-ring tribometer. The investigation was conducted at ambient temperature to determ...In order to reveal the wear mechanism of ceramic cutting tools in real cutting process, a simulation test was carried out on a block-on-ring tribometer. The investigation was conducted at ambient temperature to determine the wear behaviour of ceramic/metal tribe-systems under boundary lubrication of water and oil. In this test, the boundary lubrication conditions were provided by dropping oil or water into contact area at a rate of 5 drops per minute (about 0.1 ml/min). The tested materials are Al2O3-Ti(CN) composite ceramic, Al(purity>99.5 wt pet), Fe(C<0.04 wt pet) and a stainless steel (ASTM 302), which combined into three ceramic/metal frictional pairs. The test results indicate that wear loss of the materials increases with load and speed. Compared with unlubricated conditions, the boundary lubrication condition made the materials wear more serious, which show that lubricating method is very important to a tribe system, and unsuitable lubricating method could increase the wear of materials instead of reducing it. The surfaces of the ceramic and the metallic samples were analysed by using a scanning electron microscope with energy-dispersive X-ray attachment, which indicate that material transfer occurred between the ceramic and metallic materials. The wear mechanism was discussed.展开更多
基金the National Natural Science Foundation of China(№39570336).
文摘AIM To compare the effects of liposomes andglyco-poly-L-lysine on liver targeted uptake andexpression of plasmid in rat liver.METHODS After binding with lipofectamine orgalactose-terminal glyco-poly-L-lysine,theplasmid could be expressed in eukaryotic cellswhen injected into Wistar rats by intravenousroute.At different time intervals after the injection,the distribution and expression of the plasmid inliver of rats were observed and compared using insitu hybridization and immunohistochemistry.RESULTS The expression of the plasmid bindingto liposomes or G-PLL could be markedly observed24 h later,and began to decrease one week later,but it still could be observed up to three weeks.Both liposomes and G-PLL could deliver theplasmid to the liver effectively,but the effect of thelatter was better than the former concerning thedistribution and expression of the plasmid targeteduptake in the liver.CONCLUSION G-PLL is better than liposome asthe targeted carrier for delivering exogenous genesto the liver.
文摘In this paper the persistent currents of ideal toroidal single-wall carbon nanotubes (TSWNTs) are calculated from the tight-binding model and the periodic boundary conditions. The electronic structure and persistent current of a TSWNT strongly depend on its helicity and longitudinal circumference, making the TSWNTs a geometry-sensitive kind of materials. The interatomic carbonic interactions other than pp pi-type are also studied and are found to introduce more steps to the persistent current. The diamagnetic-paramagnetic transitions occur more frequently, and the persistent current depends on the interaction energy values, while the periodicity of magnetic flux preserves.
文摘The antiwear properties of two wheel/rail lubricating oils were tested and compared on an Amsler machine. Under same testing conditions, oil A (developed by authors) showed much better wear resistance and higher load-carrying capacity than oil B (imported from abroad). The X-ray diffraction (XRD) analyses of the worn surfaces showed that different extreme pressure (EP) lubricating films were formed on the surfaces when the rollers were lubricated with different oils under boundary lubrication condition. The EP film of oil A was a composite film containing three compounds, FeO, FeSx and FeP, while oil B formed only a simple EP film of FePO4. The composite EP film showed lower shear strength and better antiwear property than the simple EP film, which brought about different wear resistance df the two wheel/rail lubricating oils.
文摘In order to reveal the wear mechanism of ceramic cutting tools in real cutting process, a simulation test was carried out on a block-on-ring tribometer. The investigation was conducted at ambient temperature to determine the wear behaviour of ceramic/metal tribe-systems under boundary lubrication of water and oil. In this test, the boundary lubrication conditions were provided by dropping oil or water into contact area at a rate of 5 drops per minute (about 0.1 ml/min). The tested materials are Al2O3-Ti(CN) composite ceramic, Al(purity>99.5 wt pet), Fe(C<0.04 wt pet) and a stainless steel (ASTM 302), which combined into three ceramic/metal frictional pairs. The test results indicate that wear loss of the materials increases with load and speed. Compared with unlubricated conditions, the boundary lubrication condition made the materials wear more serious, which show that lubricating method is very important to a tribe system, and unsuitable lubricating method could increase the wear of materials instead of reducing it. The surfaces of the ceramic and the metallic samples were analysed by using a scanning electron microscope with energy-dispersive X-ray attachment, which indicate that material transfer occurred between the ceramic and metallic materials. The wear mechanism was discussed.
