嗜盐放线菌由于其独特的生理特性和代谢机制,可以产生结构新颖、活性迥异的次生代谢产物。本文以新疆罗布泊极端环境嗜盐放线菌TRM45306为研究对象,通过形态学观察、生物学特征和16S r DNA序列分析,确定TRM45306的分类地位;通过萃取、...嗜盐放线菌由于其独特的生理特性和代谢机制,可以产生结构新颖、活性迥异的次生代谢产物。本文以新疆罗布泊极端环境嗜盐放线菌TRM45306为研究对象,通过形态学观察、生物学特征和16S r DNA序列分析,确定TRM45306的分类地位;通过萃取、硅胶柱层析、凝胶柱层析等方法对发酵产物中次生代谢产物进行分离纯化,利用波谱学方法鉴定化合物结构。结果 TRM45306被鉴定为中度嗜盐性链霉菌,与菌株Streptomyces rochei NBRC 12908(T)相似度为100%;从发酵液中分离得到4个单体化合物,分别被鉴定为16α-甲基-11β,17α,21-三羟基-9α-氟孕甾-1,4-二烯-3,20-二酮-21-醋酸酯(45306-1)、谷甾醇-3-O-葡萄糖苷(45306-2)、Nb-乙酰色胺(45306-3)和N-丙酰色胺(45306-4)。此研究结果可为新疆嗜盐放线菌次生代谢产物的挖掘提供理论依据和技术支持,对新疆极端环境放线菌资源的开发具有重要意义。展开更多
The excavation of foundation pit generates soil deformation around existing metro tunnel with shield driving method,which may lead to the deformation of tunnel lining.It is a challenge to evaluate the deformation of s...The excavation of foundation pit generates soil deformation around existing metro tunnel with shield driving method,which may lead to the deformation of tunnel lining.It is a challenge to evaluate the deformation of shield tunnel accurately and take measures to reduce the tunnel upward displacement as much as possible for geotechnical engineers.A new simplified analytical method is proposed to predict the longitudinal deformation of existing metro tunnel due to excavation unloading of adjacent foundation pit in this paper.Firstly,the additional stress of soils under vertical axisymmetric load in layered soil is obtained by using elastic multi-layer theory.Secondly,the metro tunnel is regarded as a Timoshenko beam supported by Winkler foundation so that the shear effect of tunnels can be taken into account.The additional stress acting on the tunnel due to excavation unloading in layered soil are compared with that in homogeneous soil.Additionally,the effectiveness of the analytical solution is verified via two actual cases.Moreover,parametric analysis is conducted to investigate the responses of the metro tunnel by considering such factors as the variation of subgrade coefficient,offset distance from the excavation center to tunnel longitudinal axis as well as equivalent shear stiffness.The proposed method can be used to provide theoretical basis for similar engineering project.展开更多
目的研究巨车前Plantago maxima Juss.ex Jacq.的化学成分。方法巨车前80%乙醇提取物采用大孔树脂、制备HPLC、ODS、Sephadex LH-20进行分离纯化,根据理化性质及波谱数据鉴定所得化合物的结构。结果从中分离得到18个化合物,分别鉴定为...目的研究巨车前Plantago maxima Juss.ex Jacq.的化学成分。方法巨车前80%乙醇提取物采用大孔树脂、制备HPLC、ODS、Sephadex LH-20进行分离纯化,根据理化性质及波谱数据鉴定所得化合物的结构。结果从中分离得到18个化合物,分别鉴定为肉苁蓉苷F(1)、顺式香豆酸-4-O-β-D-吡喃葡萄糖苷(2)、二氢红花菜豆酸(3)、长寿花糖苷(4)、大车前苷(5)、印度荆芥苷(6)、3′-羟基野黄芩素-7-O-(6″-O-反式阿魏酰基)-β-吡喃葡萄糖苷(7)、木犀草素-3′-甲氧基-6-羟基-7-O-β-D-吡喃葡萄糖苷(8)、丁香脂素-4′-O-β-D-单葡糖苷(9)、野黄芩素-7-O-β-D-吡喃葡萄糖苷(10)、木犀草苷(11)、毛蕊花糖苷(12)、异毛蕊花糖苷(13)、胡麻素(14)、7-氧代菜油甾醇(15)、邻苯二甲酸二丁酯(16)、β-谷甾醇(17)和7-氧代-β-谷甾醇(18)。结论化合物2~4、7、9、15、18均为首次从车前属植物中分离得到,化合物1、5~6、8、10、13~14、16~17为首次从该植物中分离得到。展开更多
基金supported by the National Natural Science Foundation of China (Grant No. 51302079 and U1510103)the Natural Science Foundation of Hunan Province (Grant No. 2017JJ1008)
基金Project(51568006)supported by the National Natural Science Foundation of ChinaProject(2018JJA160134)supported by the Natural Science Foundation of Guangxi Province,China。
文摘The excavation of foundation pit generates soil deformation around existing metro tunnel with shield driving method,which may lead to the deformation of tunnel lining.It is a challenge to evaluate the deformation of shield tunnel accurately and take measures to reduce the tunnel upward displacement as much as possible for geotechnical engineers.A new simplified analytical method is proposed to predict the longitudinal deformation of existing metro tunnel due to excavation unloading of adjacent foundation pit in this paper.Firstly,the additional stress of soils under vertical axisymmetric load in layered soil is obtained by using elastic multi-layer theory.Secondly,the metro tunnel is regarded as a Timoshenko beam supported by Winkler foundation so that the shear effect of tunnels can be taken into account.The additional stress acting on the tunnel due to excavation unloading in layered soil are compared with that in homogeneous soil.Additionally,the effectiveness of the analytical solution is verified via two actual cases.Moreover,parametric analysis is conducted to investigate the responses of the metro tunnel by considering such factors as the variation of subgrade coefficient,offset distance from the excavation center to tunnel longitudinal axis as well as equivalent shear stiffness.The proposed method can be used to provide theoretical basis for similar engineering project.
文摘目的研究巨车前Plantago maxima Juss.ex Jacq.的化学成分。方法巨车前80%乙醇提取物采用大孔树脂、制备HPLC、ODS、Sephadex LH-20进行分离纯化,根据理化性质及波谱数据鉴定所得化合物的结构。结果从中分离得到18个化合物,分别鉴定为肉苁蓉苷F(1)、顺式香豆酸-4-O-β-D-吡喃葡萄糖苷(2)、二氢红花菜豆酸(3)、长寿花糖苷(4)、大车前苷(5)、印度荆芥苷(6)、3′-羟基野黄芩素-7-O-(6″-O-反式阿魏酰基)-β-吡喃葡萄糖苷(7)、木犀草素-3′-甲氧基-6-羟基-7-O-β-D-吡喃葡萄糖苷(8)、丁香脂素-4′-O-β-D-单葡糖苷(9)、野黄芩素-7-O-β-D-吡喃葡萄糖苷(10)、木犀草苷(11)、毛蕊花糖苷(12)、异毛蕊花糖苷(13)、胡麻素(14)、7-氧代菜油甾醇(15)、邻苯二甲酸二丁酯(16)、β-谷甾醇(17)和7-氧代-β-谷甾醇(18)。结论化合物2~4、7、9、15、18均为首次从车前属植物中分离得到,化合物1、5~6、8、10、13~14、16~17为首次从该植物中分离得到。
