Dihydroartemisinin(DQHS)is obtained by reduction of artemisinin with NaBH4 as reductant,and then DHA-DQHS is prepared by esterification of docosahexaenoic acid with dihydroartemisinin in the presence of dicyclohexylca...Dihydroartemisinin(DQHS)is obtained by reduction of artemisinin with NaBH4 as reductant,and then DHA-DQHS is prepared by esterification of docosahexaenoic acid with dihydroartemisinin in the presence of dicyclohexylcarbodiimide(DCC)and 4-dimethylaminopyridine(DMAP).Antitumor activity of DHA-DQHS against CA46,Molt4 and P388 cells is tested by MTT method in parallel with artemisinin and dihydroartemisinin.Results show that the 1H NMR and ESI-MS of DHA-DQHS are in agreement with its chmical structure.IC50 of DHA-DQHS on CA46,Molt4 and P388 cells are 0.024,0.076 and 0.105 mg·L-1 respectively,which are significantly lower than those of artemisinin and dihydroartemisinin,the reason for that is possibly owing to the tumor-targeting property of DHA.展开更多
The discovery of phase changings in two-dimensional(2D)materials driven by external stimuli not only helps to understand the various intriguing phases in 2D materials but also provides directions for constructing new ...The discovery of phase changings in two-dimensional(2D)materials driven by external stimuli not only helps to understand the various intriguing phases in 2D materials but also provides directions for constructing new functional devices.Here,by combining angle-resolved photoemission spectroscopy(ARPES)and in-situ alkali-metal deposition,we studied how alkali-metal adatoms affect the electronic structure of T_(d)-WTe_(2)on two different cleaved surfaces.We found that depending on the polarization direction of the cleaved surface,the alkali-metal deposition triggered two successive phase transitions on one surface of WTe_(2),while on the other surface,no phase transition was found.We attributed the observed phase transitions to a Td↑-1T′-Td↓structural transition driven by an alkali-metal induced sliding of WTe2layers.By comparing the band structure obtained in different structural phases of WTe_(2),we found that the evolution of band structure across different phases is characterized by an energy scale that could be related to the degree of orbital hybridization between two adjacent WTe_(2)layers.Our results demonstrate a method that manipulates the surface structure of bulk 2D materials.It also builds a direct correlation between the electronic structure and the degree of interlayer misalignment in this intriguing 2D material.展开更多
文摘Dihydroartemisinin(DQHS)is obtained by reduction of artemisinin with NaBH4 as reductant,and then DHA-DQHS is prepared by esterification of docosahexaenoic acid with dihydroartemisinin in the presence of dicyclohexylcarbodiimide(DCC)and 4-dimethylaminopyridine(DMAP).Antitumor activity of DHA-DQHS against CA46,Molt4 and P388 cells is tested by MTT method in parallel with artemisinin and dihydroartemisinin.Results show that the 1H NMR and ESI-MS of DHA-DQHS are in agreement with its chmical structure.IC50 of DHA-DQHS on CA46,Molt4 and P388 cells are 0.024,0.076 and 0.105 mg·L-1 respectively,which are significantly lower than those of artemisinin and dihydroartemisinin,the reason for that is possibly owing to the tumor-targeting property of DHA.
基金Project supported by the National Key Research and Development Program of China(Grant No.2022YFA1403502)the National Natural Science Foundation of China(Grant No.11888101)。
文摘The discovery of phase changings in two-dimensional(2D)materials driven by external stimuli not only helps to understand the various intriguing phases in 2D materials but also provides directions for constructing new functional devices.Here,by combining angle-resolved photoemission spectroscopy(ARPES)and in-situ alkali-metal deposition,we studied how alkali-metal adatoms affect the electronic structure of T_(d)-WTe_(2)on two different cleaved surfaces.We found that depending on the polarization direction of the cleaved surface,the alkali-metal deposition triggered two successive phase transitions on one surface of WTe_(2),while on the other surface,no phase transition was found.We attributed the observed phase transitions to a Td↑-1T′-Td↓structural transition driven by an alkali-metal induced sliding of WTe2layers.By comparing the band structure obtained in different structural phases of WTe_(2),we found that the evolution of band structure across different phases is characterized by an energy scale that could be related to the degree of orbital hybridization between two adjacent WTe_(2)layers.Our results demonstrate a method that manipulates the surface structure of bulk 2D materials.It also builds a direct correlation between the electronic structure and the degree of interlayer misalignment in this intriguing 2D material.
