Aim To investigate the chemical composition of Ranunculus sieboldii Miq..Methods Repeated column chromatography over silica gel, polyamide and RP-18 followed by gelfiltration on sephadex LH-20 were used to isolate che...Aim To investigate the chemical composition of Ranunculus sieboldii Miq..Methods Repeated column chromatography over silica gel, polyamide and RP-18 followed by gelfiltration on sephadex LH-20 were used to isolate chemical constituents, and their structures wereelucidated by extensive spectroscopic methods (UV, IR, MS, ~1H NMR, ^(13)C NMR) including 2D NMR(COSY, HMQC, HMBC, NOESY) techniques and by direct comparing spectral data with those reported inliterature. Results Five flavonoid glycosides named apigenin-4'-O-α-L-rhamnopyranoside (1),apigenin-7-O-β-D-glucopyranosyl-4'-O-α-L-rhamnopyranoside (2), apigenin-8-C-α-L-arabinopyranoside(3), apigenin-8-C-β-D-ga-lactopyranoside (4) , tricin-7-O-β-D-glucopyranoside (5), together withtricin (6), luteolin (7), scopoletin (8), esculetin (9), scoparone (10), ferulic acid (11),protocatechuic acid (12) , and tematolide (13) were isolated from the 95% etha-nolic extract of itswhole plant, and their cytotoxic activities were preliminarily tested. Conclusion Compounds 1-12were obtained from this genus and compound 13 from this species for the first time. Furthermore,compound 1 was for the first time isolated from nature while the ^(13)C NMR data of compounds 2 and3 are reported for the first time. The bioassay revealed that compound 1 was active against BEL-7407and A549 cell lines (IC_(45) 43, 77 μg·mL^(-1)), 8 and 10 showed inhibitory activities on KB celllines (IC_(50) 78, 44 μg·mL^(-1)) and HL-60 cell lines (Ic_(50) 85, 85 μg·mL^(-1)), while 7exerted moderate cytotoxic activities on KB, BFL-7407, A549 and HL-60 cell lines with their IC_(50)being 51, 55, 44 and 10 μg·mL^(-1) , respectively.展开更多
[Objective] The aim was to study the chemical constituents of Euphorbia hirta. [Method] The constituents were isolated and purified by various chromatography methods including normal phase and reverse phase silica gel...[Objective] The aim was to study the chemical constituents of Euphorbia hirta. [Method] The constituents were isolated and purified by various chromatography methods including normal phase and reverse phase silica gel as well as Sephadex LH-20 gel column, and then elucidated by spectroscopic analysis such as MS and NMR etc. Compounds 1, 4, 5 and 6 were evaluated for their immunostimulatory activity against splenic cell of mouse by FCM. [Result] Six compounds were isolated from Euphorbia hirt, and identified as diisobutyl-O-phthalate （compond 1）, diethylhexyl phthalate （compond 2）, hispidulin （compond 3）, acetyl peroxide （compond 4）, quercetein （compond 5） and gallic acid （compond 6）. All compounds were inactive against splenic cell of mouse. [Conclusion] Compounds 1, 2 and 3 were isolated from this plant for the first time, and compound 4 was the first naturally occurring compound. This study provided reference for isolating bioactive substances from Euphorbia hirta.展开更多
Learning about culture is an integral part of learning a fbreign language. Participating in speech contests gives language learners a good opportunity to know more about the culture of the target language. Such contes...Learning about culture is an integral part of learning a fbreign language. Participating in speech contests gives language learners a good opportunity to know more about the culture of the target language. Such contests allow students to learn how to write a speech for a particular audience, how to introduce a speaker, how to deliver a speech, and how to say ＂thank you＂ to the speaker. Participation in speech contests can promote insight and understanding through a comparison of American culture and the students＇ native culture. Such comparison is intended to promote better understanding of both cultures.展开更多
A generalized Yang-Mills model, which contains, besides the vector part Vμ, also a scalar part S, is constructed and the dynamical breaking of gauge symmetry in the model is also discussed. It is shown, in terms of N...A generalized Yang-Mills model, which contains, besides the vector part Vμ, also a scalar part S, is constructed and the dynamical breaking of gauge symmetry in the model is also discussed. It is shown, in terms of Nambu-Jona-Lasinio (NJL) mechanism, that the gauge symmetry breaking can be realized dynamically in the generalized Yang-Mills model. The combination of the generalized Yang-Mills model and the NJL mechanism provides a way to overcome the difficulties related to the Higgs field and the Higgs mechanism in the usual spontaneous symmetry breaking theory.展开更多
IN July,more than 1,700 top AI experts gathered at the 25th International Joint Conference on Artificial Intelligence（IJACI-16）in New York.A grand meeting for both AI researchers and practitioners,IJCAI is also one ...IN July,more than 1,700 top AI experts gathered at the 25th International Joint Conference on Artificial Intelligence（IJACI-16）in New York.A grand meeting for both AI researchers and practitioners,IJCAI is also one of the major global academic conferences in this field.One Chinese scientist stood out among the speakers.展开更多
English articles belong to a category of high frequency words. However, they also have been considered as one of the most difficult part and latest part to be fully acquired by non-native speakers. Because of this rea...English articles belong to a category of high frequency words. However, they also have been considered as one of the most difficult part and latest part to be fully acquired by non-native speakers. Because of this reason, a lot of efforts have been made to research into the acquisition of them. In China, researches on the article system were mainly focused on the analysis of functions and description of the usage. This essay intends to explore the distribution and features of English article errors made by Chinese EFL （English as a Foreign Language） learners both horizontally and longitudinally with the hope to find the possible factors which lead to the errors, so as to throw some light on English articles learning and teaching展开更多
Appraisal Theory is a part of the interpersonal metafunction in Systemic Functional Linguistics to reveal the speaker＇s attitudes and positionings. Some scholars in recent years have introduced this theory to the Chi...Appraisal Theory is a part of the interpersonal metafunction in Systemic Functional Linguistics to reveal the speaker＇s attitudes and positionings. Some scholars in recent years have introduced this theory to the Chinese reader and applied it to the study of different genres, but up to now, very little has been done to test this newly developed theory in translation studies. This paper attempts to use the Appraisal Theory as a tool to investigate speaker＇s positioning in ST （source text） and TT （target text）. The translations of part of the Q＆A （Question＆Answer） section of the Vice President Cheney＇s speech at Fudan University and their STs will be investigated in the present study. The source and target texts are first described in the appraisal theoretical framework and then compared to find out the differences in terms of the speaker＇s positioning in ST and TT. Finally, a discussion is carried out to explore possible reasons that caused the speaker＇s changed positioning from ST and TT. Our findings indicate that translator＇s role, linguistic characteristics, and translation purpose might all contribute to speaker＇s changed positioning.展开更多
文摘Aim To investigate the chemical composition of Ranunculus sieboldii Miq..Methods Repeated column chromatography over silica gel, polyamide and RP-18 followed by gelfiltration on sephadex LH-20 were used to isolate chemical constituents, and their structures wereelucidated by extensive spectroscopic methods (UV, IR, MS, ~1H NMR, ^(13)C NMR) including 2D NMR(COSY, HMQC, HMBC, NOESY) techniques and by direct comparing spectral data with those reported inliterature. Results Five flavonoid glycosides named apigenin-4'-O-α-L-rhamnopyranoside (1),apigenin-7-O-β-D-glucopyranosyl-4'-O-α-L-rhamnopyranoside (2), apigenin-8-C-α-L-arabinopyranoside(3), apigenin-8-C-β-D-ga-lactopyranoside (4) , tricin-7-O-β-D-glucopyranoside (5), together withtricin (6), luteolin (7), scopoletin (8), esculetin (9), scoparone (10), ferulic acid (11),protocatechuic acid (12) , and tematolide (13) were isolated from the 95% etha-nolic extract of itswhole plant, and their cytotoxic activities were preliminarily tested. Conclusion Compounds 1-12were obtained from this genus and compound 13 from this species for the first time. Furthermore,compound 1 was for the first time isolated from nature while the ^(13)C NMR data of compounds 2 and3 are reported for the first time. The bioassay revealed that compound 1 was active against BEL-7407and A549 cell lines (IC_(45) 43, 77 μg·mL^(-1)), 8 and 10 showed inhibitory activities on KB celllines (IC_(50) 78, 44 μg·mL^(-1)) and HL-60 cell lines (Ic_(50) 85, 85 μg·mL^(-1)), while 7exerted moderate cytotoxic activities on KB, BFL-7407, A549 and HL-60 cell lines with their IC_(50)being 51, 55, 44 and 10 μg·mL^(-1) , respectively.
基金Supported by the National Natural Science Foundation of China(21162044)Yunnan Natural Science Foundation(2009CD051)Middle-aged and Young Talents Program of Yunnan Province(2010CI040)~~
文摘[Objective] The aim was to study the chemical constituents of Euphorbia hirta. [Method] The constituents were isolated and purified by various chromatography methods including normal phase and reverse phase silica gel as well as Sephadex LH-20 gel column, and then elucidated by spectroscopic analysis such as MS and NMR etc. Compounds 1, 4, 5 and 6 were evaluated for their immunostimulatory activity against splenic cell of mouse by FCM. [Result] Six compounds were isolated from Euphorbia hirt, and identified as diisobutyl-O-phthalate （compond 1）, diethylhexyl phthalate （compond 2）, hispidulin （compond 3）, acetyl peroxide （compond 4）, quercetein （compond 5） and gallic acid （compond 6）. All compounds were inactive against splenic cell of mouse. [Conclusion] Compounds 1, 2 and 3 were isolated from this plant for the first time, and compound 4 was the first naturally occurring compound. This study provided reference for isolating bioactive substances from Euphorbia hirta.
文摘Learning about culture is an integral part of learning a fbreign language. Participating in speech contests gives language learners a good opportunity to know more about the culture of the target language. Such contests allow students to learn how to write a speech for a particular audience, how to introduce a speaker, how to deliver a speech, and how to say ＂thank you＂ to the speaker. Participation in speech contests can promote insight and understanding through a comparison of American culture and the students＇ native culture. Such comparison is intended to promote better understanding of both cultures.
文摘A generalized Yang-Mills model, which contains, besides the vector part Vμ, also a scalar part S, is constructed and the dynamical breaking of gauge symmetry in the model is also discussed. It is shown, in terms of Nambu-Jona-Lasinio (NJL) mechanism, that the gauge symmetry breaking can be realized dynamically in the generalized Yang-Mills model. The combination of the generalized Yang-Mills model and the NJL mechanism provides a way to overcome the difficulties related to the Higgs field and the Higgs mechanism in the usual spontaneous symmetry breaking theory.
文摘IN July,more than 1,700 top AI experts gathered at the 25th International Joint Conference on Artificial Intelligence（IJACI-16）in New York.A grand meeting for both AI researchers and practitioners,IJCAI is also one of the major global academic conferences in this field.One Chinese scientist stood out among the speakers.
文摘English articles belong to a category of high frequency words. However, they also have been considered as one of the most difficult part and latest part to be fully acquired by non-native speakers. Because of this reason, a lot of efforts have been made to research into the acquisition of them. In China, researches on the article system were mainly focused on the analysis of functions and description of the usage. This essay intends to explore the distribution and features of English article errors made by Chinese EFL （English as a Foreign Language） learners both horizontally and longitudinally with the hope to find the possible factors which lead to the errors, so as to throw some light on English articles learning and teaching
文摘Appraisal Theory is a part of the interpersonal metafunction in Systemic Functional Linguistics to reveal the speaker＇s attitudes and positionings. Some scholars in recent years have introduced this theory to the Chinese reader and applied it to the study of different genres, but up to now, very little has been done to test this newly developed theory in translation studies. This paper attempts to use the Appraisal Theory as a tool to investigate speaker＇s positioning in ST （source text） and TT （target text）. The translations of part of the Q＆A （Question＆Answer） section of the Vice President Cheney＇s speech at Fudan University and their STs will be investigated in the present study. The source and target texts are first described in the appraisal theoretical framework and then compared to find out the differences in terms of the speaker＇s positioning in ST and TT. Finally, a discussion is carried out to explore possible reasons that caused the speaker＇s changed positioning from ST and TT. Our findings indicate that translator＇s role, linguistic characteristics, and translation purpose might all contribute to speaker＇s changed positioning.
