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The Qinghai-Tibet railway, the highest railway in terms of elevation, was built under the harshest of weather conditions in the world. A new technique, called the ventiduct embankment, was used for the first time in railway construction in the Qinghai-Tibet permafrost region of China to overcome the specific difficulties of the permafrost plateau. To evaluate its effectiveness, several full-scale test embankments were constructed at a representative field site, the Qing-shuihe experimental section. The effectiveness of the ventiduct embankment structure has been verified by comparing it with the performance of the nearby control embankment in terms of permafrost table, settlement, and thaw depth. These observations are presented in this paper. The ventiduct embankment structure based on this study has been adopted in Qinghai-Tibet permafrost railway construction. DOI: 10.1061/(ASCE)0887-381 X(2008)22:4(124) CE Database subject headings: China; Rail transportation; Permafrost; Embankments; Settlement; Deformation.

Seven new secoiridoids, swertianglide (1) and swertianosides A-F (2-7), together with fifteen known compounds, were isolated from the whole plants of Swertia angustifolia. Their structures were elucidated on the basis of extensive spectroscopic analyses ([α](D), UV, IR, MS, 1D- and 2D-NMR). Fourteen compounds were evaluated for their anti-hepatitis B virus (HBV) activities on the Hep G 2.2.15 cell line in vitro. Compound 2, an unusual secoiridoid glycoside dimer, showed significant activities inhibiting the secretion of HBsAg (IC₅₀ 0.18 mM, SI 3.11) and HBeAg (IC₅₀ 0.12 mM, SI 4.67)., (© Georg Thieme Verlag KG Stuttgart · New York.)