Twelve morphological characteristics in 61 fossil crayfish specimens, which came from the Upper Jurassic Yixian Formation, are discussed respectively in the present paper. A study of these new and better preserved mat...Twelve morphological characteristics in 61 fossil crayfish specimens, which came from the Upper Jurassic Yixian Formation, are discussed respectively in the present paper. A study of these new and better preserved materials allows us to add to and revise the original description for Family Cricoidoscelosidae. In our collection, no modifications of the second pleopod of the males have yet been noted. This would be a crucial factor for the diagnosis of the family. Based on the presence of annulus ventralis in both Cricoidoscelosus and Palaeocambarus, they would appear to be very closely allied to those characteristics of the Family Cambaridae. In regard to the family Protastacidae, we seriously doubt it is actually crayfish, in light of the lack of any apomorphies identifiable within the Astacida, and their marine habitat.展开更多
AIM To compare the effects of intravenous routeand peritoneal route on liver targeted uptake andexpression of plasmid delivered by galactose-terminal glyco-poly-L-lysine(G-PLL).METHODS The plasmid pTM/MMP-1 which coul...AIM To compare the effects of intravenous routeand peritoneal route on liver targeted uptake andexpression of plasmid delivered by galactose-terminal glyco-poly-L-lysine(G-PLL).METHODS The plasmid pTM/MMP-1 which couldbe expressed in eukaryotic cells was bound to G-PLL,and was then transferred into Wistar rats byintravenous and intraperitoneal injection.Theexpression and distribution of the plasmid wereobserved at different time periods by in situhybridization and immunohistochemistry.RESULTS The plasmid could be expressedsignificantly within 24 h after being transferred invivo by both intravenous and intraperitonealroutes.One week later the expression began todecrease,and could still be observed three weekslater.Although both the intravenous andintraperitoneal route could target-specificallydeliver the plasmid to the liver,the effect of theformer was better as compared to that of the latter.CONCLUSION Intravenous route is better for livertargeted uptake and expression of G-PLL-boundplasmids than the peritoneal route.展开更多
INTERACTION between laser and material is closely related to background besides properties oflaser and material. The interaction process can be influenced to a great extent by ambient at-mosphere and pressures. In the...INTERACTION between laser and material is closely related to background besides properties oflaser and material. The interaction process can be influenced to a great extent by ambient at-mosphere and pressures. In the present work, a time and space resolved diagnostic tech-nique was used to study the emission spectrum from the plume produced by a pulsed laser on展开更多
IN recent years, giant magneto-resistance (GMR) effects have been observed in some binary composite systems such as multi-layered and granular films of Fe, Co, Ni and Cr, Ag, Cu and attracted considerable interest due...IN recent years, giant magneto-resistance (GMR) effects have been observed in some binary composite systems such as multi-layered and granular films of Fe, Co, Ni and Cr, Ag, Cu and attracted considerable interest due to their potential applications in magnetic recording heads and field sensors. However, a notable GMR effect in these films always requires a strong external magnetic field at low temperature. More recently, Mohri et al. have discovered展开更多
Methyl 3-deoxy-3-(diphenylphosphino)-4,6-O-benzylidene-alpha-D-altropyranoside (1) and methyl 2-deoxy-2-(diphenylphosphino)-4,6-O-benzylidene-alpha-D-altropyranoside (2) were prepared from methyl 2,3-anhydro-4,6-O-ben...Methyl 3-deoxy-3-(diphenylphosphino)-4,6-O-benzylidene-alpha-D-altropyranoside (1) and methyl 2-deoxy-2-(diphenylphosphino)-4,6-O-benzylidene-alpha-D-altropyranoside (2) were prepared from methyl 2,3-anhydro-4,6-O-benzylidene-O-D-mannopyranoside and methyl 2,3-anhydro-4,6-O-benzylidene-alpha-D-allopyranoside, respectively, via regioselective and stereospecific ring-opening reactions in high yields. Compounds 1 and 2 were oxidized to give the corresponding phosphine oxides (3 and 4).展开更多
The isoelectric point (IEP) and zero point of charge (ZPC) of magnesium aluminum hydroxide were studied by electrophoresis method, potentiometric titration method, and elemental analysis. Results showed that the charg...The isoelectric point (IEP) and zero point of charge (ZPC) of magnesium aluminum hydroxide were studied by electrophoresis method, potentiometric titration method, and elemental analysis. Results showed that the charge of magnesium aluminum hydroxide was composed of variable charge and permanent positive charge. Because of the permanent positive charge, the IEP and ZPC obtained were higher than calculated. The LEP decreased and ZPC increased as X increased.展开更多
基金This work was supported by the Chinese Academy of Sciences (Grant No. KZ951-B1-410-02) the Netherlands Organization for Scientific Research (750-195-12) and the Royal Netherlands Academy of Sciences.
文摘Twelve morphological characteristics in 61 fossil crayfish specimens, which came from the Upper Jurassic Yixian Formation, are discussed respectively in the present paper. A study of these new and better preserved materials allows us to add to and revise the original description for Family Cricoidoscelosidae. In our collection, no modifications of the second pleopod of the males have yet been noted. This would be a crucial factor for the diagnosis of the family. Based on the presence of annulus ventralis in both Cricoidoscelosus and Palaeocambarus, they would appear to be very closely allied to those characteristics of the Family Cambaridae. In regard to the family Protastacidae, we seriously doubt it is actually crayfish, in light of the lack of any apomorphies identifiable within the Astacida, and their marine habitat.
基金National Natural Science Foundation of China(№39570336).
文摘AIM To compare the effects of intravenous routeand peritoneal route on liver targeted uptake andexpression of plasmid delivered by galactose-terminal glyco-poly-L-lysine(G-PLL).METHODS The plasmid pTM/MMP-1 which couldbe expressed in eukaryotic cells was bound to G-PLL,and was then transferred into Wistar rats byintravenous and intraperitoneal injection.Theexpression and distribution of the plasmid wereobserved at different time periods by in situhybridization and immunohistochemistry.RESULTS The plasmid could be expressedsignificantly within 24 h after being transferred invivo by both intravenous and intraperitonealroutes.One week later the expression began todecrease,and could still be observed three weekslater.Although both the intravenous andintraperitoneal route could target-specificallydeliver the plasmid to the liver,the effect of theformer was better as compared to that of the latter.CONCLUSION Intravenous route is better for livertargeted uptake and expression of G-PLL-boundplasmids than the peritoneal route.
基金This work was supported by the National Natural Science Foundation of China (Grant No. 19374039)the Natural Science Foundation of Shandong Province (Grant No. 94A0707)
文摘INTERACTION between laser and material is closely related to background besides properties oflaser and material. The interaction process can be influenced to a great extent by ambient at-mosphere and pressures. In the present work, a time and space resolved diagnostic tech-nique was used to study the emission spectrum from the plume produced by a pulsed laser on
文摘IN recent years, giant magneto-resistance (GMR) effects have been observed in some binary composite systems such as multi-layered and granular films of Fe, Co, Ni and Cr, Ag, Cu and attracted considerable interest due to their potential applications in magnetic recording heads and field sensors. However, a notable GMR effect in these films always requires a strong external magnetic field at low temperature. More recently, Mohri et al. have discovered
基金Project supported by the State Key Project for Fundamental Research and the National Natural Science Foundation of China.
文摘Methyl 3-deoxy-3-(diphenylphosphino)-4,6-O-benzylidene-alpha-D-altropyranoside (1) and methyl 2-deoxy-2-(diphenylphosphino)-4,6-O-benzylidene-alpha-D-altropyranoside (2) were prepared from methyl 2,3-anhydro-4,6-O-benzylidene-O-D-mannopyranoside and methyl 2,3-anhydro-4,6-O-benzylidene-alpha-D-allopyranoside, respectively, via regioselective and stereospecific ring-opening reactions in high yields. Compounds 1 and 2 were oxidized to give the corresponding phosphine oxides (3 and 4).
文摘The isoelectric point (IEP) and zero point of charge (ZPC) of magnesium aluminum hydroxide were studied by electrophoresis method, potentiometric titration method, and elemental analysis. Results showed that the charge of magnesium aluminum hydroxide was composed of variable charge and permanent positive charge. Because of the permanent positive charge, the IEP and ZPC obtained were higher than calculated. The LEP decreased and ZPC increased as X increased.
