This paper chiefly examines the attitudes of second language learners,specifically,Chinese postgraduate students studying in the UK,towards code-switching between English and Mandarin in group discussion in L2 classro...This paper chiefly examines the attitudes of second language learners,specifically,Chinese postgraduate students studying in the UK,towards code-switching between English and Mandarin in group discussion in L2 classroom.Questionnaire is implemented as the data collection method and yields some corresponding findings based on research questions.Meanwhile,recent research on code-switching in classroom is introduced briefly.Moreover,limitations and pedagogical implication of the original research mentioned above are elaborated,as well as the implied future research is presented in this area.展开更多
A new 6,7-seco-ent-kaurane diterpenoid, together with two known ones, was isolated from the leaves of Isodon eriocalyx var. laxiflora C. Y. Wu & H. W. Li. Their structures were established by spectroscopic methods.
The high morbidity generated by the infection caused by parasites of the genus Leishmania, make of this infection into one of the vector-borne infectious diseases most relevant worldwide, which added to the fact that ...The high morbidity generated by the infection caused by parasites of the genus Leishmania, make of this infection into one of the vector-borne infectious diseases most relevant worldwide, which added to the fact that the drugs used for its treatment are far from be optimal and considering that prophylactic approaches (such as the development of a vaccine) still seems far from being achieved, make of the search for new therapeutic alternatives for safe and effective treatment of this disease one of the most accurate approaches to the control of this disease. In this study we evaluated the antileishmanial and immunomodu- latory activity of the compound 11α,19β-dihydroxy- 7-acetoxy-7-deoxoichangin (a seco-limonid molecule) through: 1) evaluation of its cytotoxicity over promastigotes and axenic amastigotes of L. (V) panamensis, 2) determination of its ability to induce the control of in vitro infection, using infected murine cells (J774.2) and human dendritic cells (hDCs), 3) quantifying the levels of pro-inflammatory cytokines, (iv) evaluating the expression of cell markers associated with hDCs maturation, and (v) determinating the production of nitric oxide free radicals (NO). In this regard, this seco-limonoid exhibited an antileishmanial activity represented in the reduction of in vitro infection in J774.2 cells and hDCs, with a EC50 of 7.9 μM (4.48 μg/mL) and 25.5 μM (14.39 μg/mL), respectively, and additionally, we observed an increase on the production of IL-12p70, TNF-α and NO, as also, in the number of hDCs HLA-DR-positive in treated infected hDCs. These findings suggest that anti-lei- shmanial activity of this compound could be associated with the potential “reactivation” of phagocytic cell that is “paralyzed” by the infection, generating an immune phenotype associated with protection.展开更多
The density functional method(B3P86/6-311G) is used for calculating the possible structures of SeC, SeO, and SeCO molecules. The result shows that the ground state of the SeC molecule is1Σ, the equilibrium nuclear di...The density functional method(B3P86/6-311G) is used for calculating the possible structures of SeC, SeO, and SeCO molecules. The result shows that the ground state of the SeC molecule is1Σ, the equilibrium nuclear distance is RSeC= 0.1699 nm, and the dissociation energy is De = 8.7246 eV. The ground state of the SeO molecule is3Σ, with equilibrium nuclear distance RSeO= 0.1707 nm and dissociation energy De = 7.0917 eV. There are two structures for the ground state of the SeCO molecule: Se=C=O and Se=O=C. The linear Se=C=O is1Σ. Its equilibrium nuclear distances and dissociation energy are RSeC= 0.1715 nm, RCO= 0.1176 nm and 18.8492 eV, respectively. The other structure Se=O=C is1Σ. Its equilibrium nuclear distances and dissociation energy are RCO= 0.1168 nm, RSeO= 0.1963 nm and 15.5275 eV,respectively. The possible dissociative limit of the SeCO molecule is analyzed. The potential energy function for the SeCO molecule has been obtained from the many-body expansion theory. The contour of the potential energy curve describes the structure characters of the SeCO molecule. Furthermore, contours of the molecular stretching vibration based on this potential energy function are discussed.展开更多
The synthesis of a new N,19-seco norditerpenoid alkaloid 7 bearing nitro group from yunaconitine 1 as the starting material through a series of steps was described.
A facile synthetic route to two seco-eudesmane, 4, 5-dioxo-10-epi-4, 5-seco-γ- eudesmane (1) and 4, 5-dioxo-10-epi-4, 5-seco-γ-eudesmol (2) from (+)-dihydrocarvone has been described. Avoiding expensive reagents, th...A facile synthetic route to two seco-eudesmane, 4, 5-dioxo-10-epi-4, 5-seco-γ- eudesmane (1) and 4, 5-dioxo-10-epi-4, 5-seco-γ-eudesmol (2) from (+)-dihydrocarvone has been described. Avoiding expensive reagents, this highly economic method especially suits for the synthesis of 4, 5-seco-eudesman-type and ophianon-type sesquiterpenes with a double bond at position 11 and 12.展开更多
Two novel compounds, named sphaerophyside SC and SD were isolated from the ethanolic extract of the seeds of Sphaerophysa salsula. The structures of the compounds were elucidated on the basis of the NMR data, especial...Two novel compounds, named sphaerophyside SC and SD were isolated from the ethanolic extract of the seeds of Sphaerophysa salsula. The structures of the compounds were elucidated on the basis of the NMR data, especially the 2D NMR technique.展开更多
Four new 3,4-seco-labdane diterpenoids,nudiflopenes J-M,were isolated from the leaves of Callicarpa nudiflora along with six known compounds.The structures of these diterpenoids were determined by comprehensive spectr...Four new 3,4-seco-labdane diterpenoids,nudiflopenes J-M,were isolated from the leaves of Callicarpa nudiflora along with six known compounds.The structures of these diterpenoids were determined by comprehensive spectroscopic analysis.All the isolated compounds were evaluated for their inhibitory effects on NO production in LPS-stimulated RPMs and RAW264.7 cells.The results suggest that nudiflopenes J-M and other four known compounds showed significant inhibitory effects against NO production comparable to the positive control dexamethasone.展开更多
Four new seco-dibenzocyclooctadiene lignans,kadlongilignans A-D(1-4),consisting of a rare 6,7-seco-(1),two 15,16-seco-(2 and 3) and a 9,10-seco-dibenzocyclooctadiene(4) lignans,were isolated from the roots of Kadsura ...Four new seco-dibenzocyclooctadiene lignans,kadlongilignans A-D(1-4),consisting of a rare 6,7-seco-(1),two 15,16-seco-(2 and 3) and a 9,10-seco-dibenzocyclooctadiene(4) lignans,were isolated from the roots of Kadsura longipedunculata.Their structures were elucidated by spectroscopic analysis,including extensive NM R,MS and ECD(electronic circular dichroism) spectra.Compounds 3 and 4 exhibited potent inhibitory activities against NO(nitric oxide) production of LPS(lipopolysaccharide)-induced murine macrophages with the inhibition rates of 36.3% and 26.9%,respectively.展开更多
The synthesis of (S)-(+)-tylophorine and its seco analogues has been accomplished by using free radical reaction. -N-(2,3,6,7-Tetramethoxyphenanthren-9-ylmethyl)-2-bromomethylpyrrolidine (7) and -N-(2,3,6,7-tetrametho...The synthesis of (S)-(+)-tylophorine and its seco analogues has been accomplished by using free radical reaction. -N-(2,3,6,7-Tetramethoxyphenanthren-9-ylmethyl)-2-bromomethylpyrrolidine (7) and -N-(2,3,6,7-tetramethoxyphenanthren-9-ylcarbonyl)-2-bromomethylpyrrolidine (9) have been obtained for the first time in three and two linear steps from 2,3,6,7-tetramethoxyphenanthrene-9-carboxylic acid (4), respectively. When bromide 7 was subjected to the action of tri-n-butyltin hydride and catalytic amount of azobisisobutyronitrile in acetonitrile at reflux, only a new structural N-((2,3,6,7-tetramethoxyphenanthren-9-yl)methyl)piperidine (2) was obtained in excellent yield, without expected (+)- ty- lophorine. As an alternative route, when bromide 9 was treated with azobisisobutyronitrile and tri-n-butyltin hydride in toluene at reflux, tylophorin-9-one (10) was provided in 33.6% yield. At the same time, a new structural (+)-N-((2,3,6,7-tetramethoxyphenanthren-9-yl)carbonyl)-2-methylpyrrolidine (11) was afforded as the main product in 65% yield. Notably, azobisisobutyronitrile plays dual roles in this reaction, and the possible mechanism has been described. Compounds 10 and 11 were reduced by lithium aluminum hydride to give (+)-tylophorine and (+)-N-((2,3,6,7-tetramethoxyphenanthren-9-yl) methyl)-2-methylpyrrolidine (3), respectively.展开更多
One new 6,7-seco-enr-kaurane diterpenoid,sculponin T(1),was isolated from the aerial parts of Isodon sculponeatus,along with four known analogs,sculponeatin J(2),sculponeatin K(3),sculponeatin C(4),and sculponeatin Q(...One new 6,7-seco-enr-kaurane diterpenoid,sculponin T(1),was isolated from the aerial parts of Isodon sculponeatus,along with four known analogs,sculponeatin J(2),sculponeatin K(3),sculponeatin C(4),and sculponeatin Q(5).Their structures were elucidated by extensive spectroscopic analysis and by comparison with data reported in the literature.Significant cytotoxic activity was observed for compound 2 against five human tumor cell lines with IC_(50) values ranging from 1.8 μmol/L to 3.3 μmol/L,and it also inhibited NO production in LPS-stimulated RAW264.7 cells,with IC_(50) value of 3.3 μmol/L.展开更多
文摘This paper chiefly examines the attitudes of second language learners,specifically,Chinese postgraduate students studying in the UK,towards code-switching between English and Mandarin in group discussion in L2 classroom.Questionnaire is implemented as the data collection method and yields some corresponding findings based on research questions.Meanwhile,recent research on code-switching in classroom is introduced briefly.Moreover,limitations and pedagogical implication of the original research mentioned above are elaborated,as well as the implied future research is presented in this area.
基金The authors wish to thank all members of the analytical group of Phytochemistry Laboratory of Kunming Institute of Botany Academic Sinica for the measurement of spectral data.
文摘A new 6,7-seco-ent-kaurane diterpenoid, together with two known ones, was isolated from the leaves of Isodon eriocalyx var. laxiflora C. Y. Wu & H. W. Li. Their structures were established by spectroscopic methods.
文摘The high morbidity generated by the infection caused by parasites of the genus Leishmania, make of this infection into one of the vector-borne infectious diseases most relevant worldwide, which added to the fact that the drugs used for its treatment are far from be optimal and considering that prophylactic approaches (such as the development of a vaccine) still seems far from being achieved, make of the search for new therapeutic alternatives for safe and effective treatment of this disease one of the most accurate approaches to the control of this disease. In this study we evaluated the antileishmanial and immunomodu- latory activity of the compound 11α,19β-dihydroxy- 7-acetoxy-7-deoxoichangin (a seco-limonid molecule) through: 1) evaluation of its cytotoxicity over promastigotes and axenic amastigotes of L. (V) panamensis, 2) determination of its ability to induce the control of in vitro infection, using infected murine cells (J774.2) and human dendritic cells (hDCs), 3) quantifying the levels of pro-inflammatory cytokines, (iv) evaluating the expression of cell markers associated with hDCs maturation, and (v) determinating the production of nitric oxide free radicals (NO). In this regard, this seco-limonoid exhibited an antileishmanial activity represented in the reduction of in vitro infection in J774.2 cells and hDCs, with a EC50 of 7.9 μM (4.48 μg/mL) and 25.5 μM (14.39 μg/mL), respectively, and additionally, we observed an increase on the production of IL-12p70, TNF-α and NO, as also, in the number of hDCs HLA-DR-positive in treated infected hDCs. These findings suggest that anti-lei- shmanial activity of this compound could be associated with the potential “reactivation” of phagocytic cell that is “paralyzed” by the infection, generating an immune phenotype associated with protection.
文摘The density functional method(B3P86/6-311G) is used for calculating the possible structures of SeC, SeO, and SeCO molecules. The result shows that the ground state of the SeC molecule is1Σ, the equilibrium nuclear distance is RSeC= 0.1699 nm, and the dissociation energy is De = 8.7246 eV. The ground state of the SeO molecule is3Σ, with equilibrium nuclear distance RSeO= 0.1707 nm and dissociation energy De = 7.0917 eV. There are two structures for the ground state of the SeCO molecule: Se=C=O and Se=O=C. The linear Se=C=O is1Σ. Its equilibrium nuclear distances and dissociation energy are RSeC= 0.1715 nm, RCO= 0.1176 nm and 18.8492 eV, respectively. The other structure Se=O=C is1Σ. Its equilibrium nuclear distances and dissociation energy are RCO= 0.1168 nm, RSeO= 0.1963 nm and 15.5275 eV,respectively. The possible dissociative limit of the SeCO molecule is analyzed. The potential energy function for the SeCO molecule has been obtained from the many-body expansion theory. The contour of the potential energy curve describes the structure characters of the SeCO molecule. Furthermore, contours of the molecular stretching vibration based on this potential energy function are discussed.
基金Financial support for this research was provided by the National Natural Science Foundation of China (No. 3007088). We are grateful to Professor Xiao-Tian Liang for his advice on this manuscript.
文摘The synthesis of a new N,19-seco norditerpenoid alkaloid 7 bearing nitro group from yunaconitine 1 as the starting material through a series of steps was described.
基金This work was financially supported by the National Natural Science Foundation of China(No.20272021).
文摘A facile synthetic route to two seco-eudesmane, 4, 5-dioxo-10-epi-4, 5-seco-γ- eudesmane (1) and 4, 5-dioxo-10-epi-4, 5-seco-γ-eudesmol (2) from (+)-dihydrocarvone has been described. Avoiding expensive reagents, this highly economic method especially suits for the synthesis of 4, 5-seco-eudesman-type and ophianon-type sesquiterpenes with a double bond at position 11 and 12.
文摘Two novel compounds, named sphaerophyside SC and SD were isolated from the ethanolic extract of the seeds of Sphaerophysa salsula. The structures of the compounds were elucidated on the basis of the NMR data, especially the 2D NMR technique.
基金supported by the National Natural Science Foundation of China(No.81503224)Guangdong Key Laboratory for translational Cancer research of Chinese Medicine(No.2018B030322011)+1 种基金Department of education of Guangdong Province(No.2016KZD-XM031)Science and Technology Project of Guangzhou City(No.201707010467)
文摘Four new 3,4-seco-labdane diterpenoids,nudiflopenes J-M,were isolated from the leaves of Callicarpa nudiflora along with six known compounds.The structures of these diterpenoids were determined by comprehensive spectroscopic analysis.All the isolated compounds were evaluated for their inhibitory effects on NO production in LPS-stimulated RPMs and RAW264.7 cells.The results suggest that nudiflopenes J-M and other four known compounds showed significant inhibitory effects against NO production comparable to the positive control dexamethasone.
基金financially supported by CAMS Initiative for Innovative Medicine(No.CAMS-2016-I2M-1-010)the Drug Innovation Major Project(No.2018ZX09711001-001-003)。
文摘Four new seco-dibenzocyclooctadiene lignans,kadlongilignans A-D(1-4),consisting of a rare 6,7-seco-(1),two 15,16-seco-(2 and 3) and a 9,10-seco-dibenzocyclooctadiene(4) lignans,were isolated from the roots of Kadsura longipedunculata.Their structures were elucidated by spectroscopic analysis,including extensive NM R,MS and ECD(electronic circular dichroism) spectra.Compounds 3 and 4 exhibited potent inhibitory activities against NO(nitric oxide) production of LPS(lipopolysaccharide)-induced murine macrophages with the inhibition rates of 36.3% and 26.9%,respectively.
基金Supported by the National Natural Science Foundation of China (Grant No 20872072)the Key Project of Chinese Ministry of Education (Grant No 106046)
文摘The synthesis of (S)-(+)-tylophorine and its seco analogues has been accomplished by using free radical reaction. -N-(2,3,6,7-Tetramethoxyphenanthren-9-ylmethyl)-2-bromomethylpyrrolidine (7) and -N-(2,3,6,7-tetramethoxyphenanthren-9-ylcarbonyl)-2-bromomethylpyrrolidine (9) have been obtained for the first time in three and two linear steps from 2,3,6,7-tetramethoxyphenanthrene-9-carboxylic acid (4), respectively. When bromide 7 was subjected to the action of tri-n-butyltin hydride and catalytic amount of azobisisobutyronitrile in acetonitrile at reflux, only a new structural N-((2,3,6,7-tetramethoxyphenanthren-9-yl)methyl)piperidine (2) was obtained in excellent yield, without expected (+)- ty- lophorine. As an alternative route, when bromide 9 was treated with azobisisobutyronitrile and tri-n-butyltin hydride in toluene at reflux, tylophorin-9-one (10) was provided in 33.6% yield. At the same time, a new structural (+)-N-((2,3,6,7-tetramethoxyphenanthren-9-yl)carbonyl)-2-methylpyrrolidine (11) was afforded as the main product in 65% yield. Notably, azobisisobutyronitrile plays dual roles in this reaction, and the possible mechanism has been described. Compounds 10 and 11 were reduced by lithium aluminum hydride to give (+)-tylophorine and (+)-N-((2,3,6,7-tetramethoxyphenanthren-9-yl) methyl)-2-methylpyrrolidine (3), respectively.
基金supported financially by the National Natural Science Foundation of China(Nos.21322204 and 81172939)the NSFC-Joint Foundation of Yunnan Province(No.U1302223)+1 种基金the Reservation-talent Project of Yunnan Province(No.2011CI043)the West Light Foundation of the Chinese Academy of Sciences(Jian-Xin Pu)
文摘One new 6,7-seco-enr-kaurane diterpenoid,sculponin T(1),was isolated from the aerial parts of Isodon sculponeatus,along with four known analogs,sculponeatin J(2),sculponeatin K(3),sculponeatin C(4),and sculponeatin Q(5).Their structures were elucidated by extensive spectroscopic analysis and by comparison with data reported in the literature.Significant cytotoxic activity was observed for compound 2 against five human tumor cell lines with IC_(50) values ranging from 1.8 μmol/L to 3.3 μmol/L,and it also inhibited NO production in LPS-stimulated RAW264.7 cells,with IC_(50) value of 3.3 μmol/L.
