The Spurge family （Euphorbiaceae） is a large family of flowering plants. Two plant species of this family were collected from the Egyptian desert, extracted with methanol subjected to silica gel column chromatograph...The Spurge family （Euphorbiaceae） is a large family of flowering plants. Two plant species of this family were collected from the Egyptian desert, extracted with methanol subjected to silica gel column chromatography to give six compounds, three compounds from each plant. The compounds isolated from the methanol extract of Euphorbia retusa Forssk were identified as kaempferol-3-beta-D glucopyranosyl （1）, 3-O-alpha-L-xylopyranosyl （1→3）-alpha-L xylopyranosyl （1→2）, beta-D glucopyranosyllup 1,12-diene-3,21-diol （2） and 5,7,8,3＇,4＇-pentahydroxy-3-methoxyflavone （3） and the compounds isolated from Euphorbia paralais L. identified as 3,5,3＇-trihydroxy-6,7-d-methoxy-4＇ （7＂-hydroxygeranyl-1＂-ether） flavones （4）, 3-O-syringic acid （1→4）-alpha-L- xylopyranosyl （1→3）, beta-D-rahminopyranosyl hederagenin （5） and 3-O-syringic acid （1→4）, beta-D-rahminopyranosyl （1→3）,beta-D-rahminopyranosyl hederagenin （6）. The structure of the isolated compounds was elucidated by chemical and spectrometric analysis such as Infera red （IR）, proton and carbon nuclear magnetic resonance （1H-, 13C-NMR） and chemical ionization mass spectrometry （CI-MS）.展开更多
In this paper, we reconsider the defining but often overlooked ‘hinge' function of megalopolises by analyzing how megalopolises have articulated national and international urban systems in the context of a global...In this paper, we reconsider the defining but often overlooked ‘hinge' function of megalopolises by analyzing how megalopolises have articulated national and international urban systems in the context of a globalizing knowledge economy. Taking the case of China's Yangtze River Delta(YRD) region, we particularly focus on knowledge circulation within and beyond the YRD region by analyzing the pattern and process of knowledge collaboration at different geographical scales during the 2004–2014 period. Results show that the structure of scientific knowledge collaboration as reflected by co-publications has been strongest at the national scale whereas that of technological knowledge collaboration as measured by co-patents has been strongest at the global scale. Despite this difference, the structure of both scientific and technological knowledge collaboration has been functionally polycentric at the megalopolitan scale but become less so at the national and global scales. The ‘globally connected but locally disconnected' pattern of Shanghai's external knowledge collaboration suggests that the gateway role of the YRD megalopolis in promoting knowledge collaboration at different geographical scales will take time before it is fully realized.展开更多
To investigate the chemical components from the stems of Casearia velutina Bl.,the constituents were isolated by repeated chromatography with silica gel,Sephadex LH-20,and ODS columns.The structures were elucidated by...To investigate the chemical components from the stems of Casearia velutina Bl.,the constituents were isolated by repeated chromatography with silica gel,Sephadex LH-20,and ODS columns.The structures were elucidated by spectroscopic analysis.Eleven triterpenoids and its glycosides were isolated from the crude extract of C.velutina,and their structures were identified as friedelin-2,3-lactone（1）,friedelane（2）,epifriedelanol（3）,friedelin（4）,2α,3α,19α-trihydroxy-urs-12-en-28-oic acid（5）,2α,3β,19α-trihydroxy-urs-12-en-28-oic acid（6）,2α,3α,23-trihydroxy-urs-12-en-28-oic acid（7）,2α,3α,23-trihydroxy-olean-12-en-28-oic acid（8）,2α,3α,19α,23-tetrahydroxy-urs-12-en-28-oic acid（9）,2α,3α,19α,23-tetrahydroxy-urs-12-en-28-oic acid-28-O-β-D-glucopyranosyl ester（10）,and 3β,19α-dihydroxy-urs-12-en-28-oic acid 3-O-α-L-arabinopyranoside（11）.All the compounds described above were isolated from this species for the first time.Compound 1 is a rarely occurred seco-friedelolactone in Flacourtiaceae.展开更多
文摘The Spurge family （Euphorbiaceae） is a large family of flowering plants. Two plant species of this family were collected from the Egyptian desert, extracted with methanol subjected to silica gel column chromatography to give six compounds, three compounds from each plant. The compounds isolated from the methanol extract of Euphorbia retusa Forssk were identified as kaempferol-3-beta-D glucopyranosyl （1）, 3-O-alpha-L-xylopyranosyl （1→3）-alpha-L xylopyranosyl （1→2）, beta-D glucopyranosyllup 1,12-diene-3,21-diol （2） and 5,7,8,3＇,4＇-pentahydroxy-3-methoxyflavone （3） and the compounds isolated from Euphorbia paralais L. identified as 3,5,3＇-trihydroxy-6,7-d-methoxy-4＇ （7＂-hydroxygeranyl-1＂-ether） flavones （4）, 3-O-syringic acid （1→4）-alpha-L- xylopyranosyl （1→3）, beta-D-rahminopyranosyl hederagenin （5） and 3-O-syringic acid （1→4）, beta-D-rahminopyranosyl （1→3）,beta-D-rahminopyranosyl hederagenin （6）. The structure of the isolated compounds was elucidated by chemical and spectrometric analysis such as Infera red （IR）, proton and carbon nuclear magnetic resonance （1H-, 13C-NMR） and chemical ionization mass spectrometry （CI-MS）.
文摘In this paper, we reconsider the defining but often overlooked ‘hinge' function of megalopolises by analyzing how megalopolises have articulated national and international urban systems in the context of a globalizing knowledge economy. Taking the case of China's Yangtze River Delta(YRD) region, we particularly focus on knowledge circulation within and beyond the YRD region by analyzing the pattern and process of knowledge collaboration at different geographical scales during the 2004–2014 period. Results show that the structure of scientific knowledge collaboration as reflected by co-publications has been strongest at the national scale whereas that of technological knowledge collaboration as measured by co-patents has been strongest at the global scale. Despite this difference, the structure of both scientific and technological knowledge collaboration has been functionally polycentric at the megalopolitan scale but become less so at the national and global scales. The ‘globally connected but locally disconnected' pattern of Shanghai's external knowledge collaboration suggests that the gateway role of the YRD megalopolis in promoting knowledge collaboration at different geographical scales will take time before it is fully realized.
基金Changjiang Scholar and Innovative Team in University (Grant No. 985-2-063-112)
文摘To investigate the chemical components from the stems of Casearia velutina Bl.,the constituents were isolated by repeated chromatography with silica gel,Sephadex LH-20,and ODS columns.The structures were elucidated by spectroscopic analysis.Eleven triterpenoids and its glycosides were isolated from the crude extract of C.velutina,and their structures were identified as friedelin-2,3-lactone（1）,friedelane（2）,epifriedelanol（3）,friedelin（4）,2α,3α,19α-trihydroxy-urs-12-en-28-oic acid（5）,2α,3β,19α-trihydroxy-urs-12-en-28-oic acid（6）,2α,3α,23-trihydroxy-urs-12-en-28-oic acid（7）,2α,3α,23-trihydroxy-olean-12-en-28-oic acid（8）,2α,3α,19α,23-tetrahydroxy-urs-12-en-28-oic acid（9）,2α,3α,19α,23-tetrahydroxy-urs-12-en-28-oic acid-28-O-β-D-glucopyranosyl ester（10）,and 3β,19α-dihydroxy-urs-12-en-28-oic acid 3-O-α-L-arabinopyranoside（11）.All the compounds described above were isolated from this species for the first time.Compound 1 is a rarely occurred seco-friedelolactone in Flacourtiaceae.
