Triterpene glycosides and glucosyl esters, and a triterpene from the leaves of Schefflera actinophylla

From the EtOAc and 1-BuOH fractions, three new ursane-type and four new lupane-type triterpenes, along with nine known glycosides and glycosyl esters of lupane-type were isolated from the leaves of Schefflera actinophylla. All the isolated compounds were obtained for the first time from this plant. The structures of the new triterpenes were determined through a combination of spectroscopic and chemical analyses.     

Search for isovector giant monopole resonances via the Pb(3He,tp) reaction

The (nat)Pb(3He,tp) reaction at E(3He) = 177 MeV was studied to identify 2Planck's over 2piomega isovector monopole strength in Bi isotopes. Monopole strength was found in the region -45相似文献   

On the Bifurcations and Multiple Endemic States of a Single Strain HIV Model Dedicated to Professor Toshikazu Sunada on the Occasion of his 60th Birthday

The dynamics of a single strain HIV model is studied.The basic reproduction number R_0 used as a bifurcation parameter shows that the system undergoes transcritical and saddle-node bifurcations.The usual threshold unit value of R_0 does not completely determine the eradication of the disease in an HIV infected person.In particular,a sub-threshold value R_C is established which determines the system's number of endemic states:multiple if R_c Ro 1,only one if R_C = R_0 = 1,and none if R_0 R_C 1.