Two new C21 steroidal glycosides,paniculatumosides H and I,together with four known ones were isolated from the roots of Cynanchum paniculatum(Bge.)Kitag.Their structures were identifed by spectroscopic methods includ...Two new C21 steroidal glycosides,paniculatumosides H and I,together with four known ones were isolated from the roots of Cynanchum paniculatum(Bge.)Kitag.Their structures were identifed by spectroscopic methods including extensive 1D and 2D NMR techniques.All compounds were subjected to detect the anti-tobacco mosaic virus(TMV)activities and their cytotoxities against three human tumor cell lines(SMMC-7721,MDA-MB-231 and A549).The results showed that compounds 1 and 5 exhibited potent protective activities against TMV,while 2,4 and 6 had moderate efects on the SMMC7721 cancer cells viability.展开更多
The structural properties, heats of formation, elastic properties, and electronic structures of four compositions of binary A1-Li intermetallics, A13Li, A1Li, A12Li3, and A14Li9, are ana- lyzed in detail by using dens...The structural properties, heats of formation, elastic properties, and electronic structures of four compositions of binary A1-Li intermetallics, A13Li, A1Li, A12Li3, and A14Li9, are ana- lyzed in detail by using density functional theory. The calculated formation heats indicate a strong chemical interaction between A1 and Li for all the A1-Li intermetallics. In partic- ular, in the Li-rich A1-Li compounds, the thermodynamic stability of intermetallics linearly decreases with increasing concentration of.Li. According to the computational single crystal elastic constants, all the four A1-Li intermetallic compounds considered here are mechani- cally stable. The polycrystalline elastic modulus and Poisson＇s ratio have been deduced by using Voigt, Reuss, and Hill approximations, and the calculated ratios of bulk modulus to shear modulus indicate that the four compositions of binary A1-Li intermetallics are brittle materials. With the increase of Li concentration, the bulk modulus of A1-Li intermetallics decreases in a linear manner.展开更多
基金supported financially by grants from the National Natural Science Foundation of China(Nos.31770389,81703393).
文摘Two new C21 steroidal glycosides,paniculatumosides H and I,together with four known ones were isolated from the roots of Cynanchum paniculatum(Bge.)Kitag.Their structures were identifed by spectroscopic methods including extensive 1D and 2D NMR techniques.All compounds were subjected to detect the anti-tobacco mosaic virus(TMV)activities and their cytotoxities against three human tumor cell lines(SMMC-7721,MDA-MB-231 and A549).The results showed that compounds 1 and 5 exhibited potent protective activities against TMV,while 2,4 and 6 had moderate efects on the SMMC7721 cancer cells viability.
文摘The structural properties, heats of formation, elastic properties, and electronic structures of four compositions of binary A1-Li intermetallics, A13Li, A1Li, A12Li3, and A14Li9, are ana- lyzed in detail by using density functional theory. The calculated formation heats indicate a strong chemical interaction between A1 and Li for all the A1-Li intermetallics. In partic- ular, in the Li-rich A1-Li compounds, the thermodynamic stability of intermetallics linearly decreases with increasing concentration of.Li. According to the computational single crystal elastic constants, all the four A1-Li intermetallic compounds considered here are mechani- cally stable. The polycrystalline elastic modulus and Poisson＇s ratio have been deduced by using Voigt, Reuss, and Hill approximations, and the calculated ratios of bulk modulus to shear modulus indicate that the four compositions of binary A1-Li intermetallics are brittle materials. With the increase of Li concentration, the bulk modulus of A1-Li intermetallics decreases in a linear manner.
