Four new indole alkaloids from Plantago asiatica

Four new indole alkaloids,plasiaticines A-D(1-4),together with two known ones,were isolated from the seeds of Plantago asiatica.The structures of the new compounds were elucidated on the basis of comprehensive analysis of spectroscopic data.All compounds were tested for their cytotoxic activity,and all compounds except 4 were tested for their acetylcholinesterase(AChE)inhibitory activities.

Four new lignans from the leaves and stems of Schisandra propinqua var.sinensis

Four new tetrahydrofuran lignans,schpropinrins A-D(1-4),together with five known ones,were isolated from the leaves and stems of Schisandra propinqua var.sinensis.Their structures,including absolute configurations,were characterized by means of spectroscopic analysis and ECD calculation.Compounds 1-4 featured a ketal or hemiketal substructure at C-7 and all of the isolates were tested for their anti-HIV integrase activity.

Three new nortriterpenoids from Schisandra wilsoniana and their anti-HIV-1 activities

Three new highly oxygenated nortriterpenoids,wilsonianadilactones D-F(1-3),were isolated from the leaves and stems of Schisandra wilsoniana.Their structures were established by means of spectroscopic analysis.Compounds 1-3 showed weak anti-HIV-1 activity with the therapeutic index(TI)values(CC50/EC50)greater than 8.16,14.7,and 17.5,respectively.

Two new neolignans from Manglietia insignis

Two new neolignans,manneoinsigins A(1)and B(2),together with four known lignans,were isolated from the leaves and stems of Manglietia insignis.The new compounds were established on the basis of extensive spectroscopic analyses.All compounds except 2 were tested for their cytotoxic activity.Compound 3 showed weak cytotoxic activity against the HL-60 human tumor cell line with the IC50 value of 23.5μM.

Numerical analysis of tunnel segments strengthened by steel-concrete composites

In order to study the feasibility of strengthening of segmental tunnel linings by using steel-concrete composites(SCC),a three-dimensional(3D)finite element(FE)model is proposed in this paper.The nonlinear mechanical behavior of concrete is described by a plastic-damage model.The nonlinearity,resulting from the interface of the SCC and reinforced concrete(RC)segments,is simulated with the help of a system of springs.The analysis results are compared with those obtained from a full-scale test of a tunnel segment.Their agreement validates the usefulness of the 3D FE model.Numerical re-analysis of the test shows that the interfacial connectors govern both the strengthening effect of SCC and the failure pattern of the strengthened segments.Thus,the force-transmitting capacity of the interfacial connectors should be concerned in design activities.As regards the circular segments,the interfacial connectors refer to both the shearing and the stripping connectors.The composite effect of the SCC and RC segments increases with the increasing number of these connectors.The latter,therefore,results in the increases of the bearing capacities and stiffnesses of the strengthened segments.Those increases become insignificant as the number of these connectors is sufficient to ensure a perfect composite effect of the SCC and RC segments.In addition,the numerical simulations show that using high-performance steel shell(HPS)or/and ultra-high-performance concrete(UHPC)is an effective way to increase the strengthening effect of SCCs.

Three new diterpenoids from Leonurus japonicus

Phytochemical investigation of the aerial parts of Leonurus japonicus led to the isolation of one unusual clerodane diterpenoid,leojaponin A（1）,characterized by a C4–C7oxa-bridge,and two new labdane diterpenoids,leojaponins B（2） and C（3）.The structures of these new compounds were determined based on extensive 1D and 2D NMR spectroscopic data.To the best of our knowledge,compound 1 is the first clerodane diterpenoid obtained from Leonurus.japonicus.All of them were evaluated for their cytotoxicity.