Molecular networking-guided chemical investigation of the Euphorbia endophyte Malbranchea umbrina D16 led to the isolation of 14 novel unusually cyclized triterpenoids(UCT)involving three different skeletal types.Comp...Molecular networking-guided chemical investigation of the Euphorbia endophyte Malbranchea umbrina D16 led to the isolation of 14 novel unusually cyclized triterpenoids(UCT)involving three different skeletal types.Compounds 1–10 are tricyclic triterpenoids featuring a 1-cyclohexyloctahydro-1H-indene core,in which 1 incoporates an unusual 7,7-dimethyl-6,8-dioxabicyclo[3.1.2]octane motif.Compounds 11–13represent a rare class of bicyclic triterpenes(6/5 ring system)containing various O-heterocycles at the side chain.Compound 14 is an acyclic triterpenoid with O-heterocycles at both ends.Their structures were assigned by spectroscopic,chemical,computational,and crystallographic means,which also allowed the stereochemical revisions of three previously reported analogues.Compound 1 significantly inhibited the adipogenesis in 3T3-L1 adipocytes via activating the AMP-activated protein kinase(AMPK)signalling.展开更多
The plasma electrolytic oxidation(PEO)coatings were produced on D16 T Al alloy in the aluminate and silicate electrolyte with and without graphene.The phase composition,microstructure and elemental distribution of the...The plasma electrolytic oxidation(PEO)coatings were produced on D16 T Al alloy in the aluminate and silicate electrolyte with and without graphene.The phase composition,microstructure and elemental distribution of the coatings were tested by X-ray diffraction(XRD),scanning electron microscope(SEM)and energy dispersive X-ray spectroscopy(EDX).The wear and corrosion resistance of PEO coatings were evaluated by dry sliding wear tests and electrochemical impedance spectroscopy(EIS).The morphology feature of the wear tracks was compared and analyzed by SEM and three-dimensional microscope.The results demonstrate that the structure,wear and corrosion resistance of PEO coatings with graphene are better than that of PEO coatings without graphene.The coating fabricated in the aluminate electrolyte with graphene exhibited the lowest roughness.The coated samples formed in silicate electrolyte with graphene displayed the thickest,densest and the most compact coating.It exhibited the best wear and corrosion resistance due to the incorporation mode of graphene in the coatings.The mechanism of graphene improving the wear and corrosion resistance of PEO coating was further discussed.In summary,the comprehensive performances of PEO coatings formed in silicate electrolyte on D16 T Al alloy are superior to that produced in aluminate electrolyte.展开更多
基金supported by the National Natural Science Foundation of China(Nos.81973195,82273804,22407144,and 82404454)the Science and Technology Program of Guangzhou,China(No.2024B03J1322)+2 种基金the Science and Technology Planning Project of Guangdong Province,China(No.2023A1111120025)the Postdoctoral Fellowship Program of CPSF(No.GZC20242113)the China Postdoctoral Science Foundation(No.2024M753800)。
摘要Molecular networking-guided chemical investigation of the Euphorbia endophyte Malbranchea umbrina D16 led to the isolation of 14 novel unusually cyclized triterpenoids(UCT)involving three different skeletal types.Compounds 1–10 are tricyclic triterpenoids featuring a 1-cyclohexyloctahydro-1H-indene core,in which 1 incoporates an unusual 7,7-dimethyl-6,8-dioxabicyclo[3.1.2]octane motif.Compounds 11–13represent a rare class of bicyclic triterpenes(6/5 ring system)containing various O-heterocycles at the side chain.Compound 14 is an acyclic triterpenoid with O-heterocycles at both ends.Their structures were assigned by spectroscopic,chemical,computational,and crystallographic means,which also allowed the stereochemical revisions of three previously reported analogues.Compound 1 significantly inhibited the adipogenesis in 3T3-L1 adipocytes via activating the AMP-activated protein kinase(AMPK)signalling.
基金the Award of Fellowship from China Scholarship Council(No.201608515038)the National Natural Science Foundation of China(No.51274170)+1 种基金the 18th College Students’Key Open Experimental Subjects of Southwest Petroleum University(No.KSZ18503)the Plan Program about Passing a Test for the Youth Technicist worked in the Laboratory of Southwest Petroleum University(No.201131010056)。
摘要The plasma electrolytic oxidation(PEO)coatings were produced on D16 T Al alloy in the aluminate and silicate electrolyte with and without graphene.The phase composition,microstructure and elemental distribution of the coatings were tested by X-ray diffraction(XRD),scanning electron microscope(SEM)and energy dispersive X-ray spectroscopy(EDX).The wear and corrosion resistance of PEO coatings were evaluated by dry sliding wear tests and electrochemical impedance spectroscopy(EIS).The morphology feature of the wear tracks was compared and analyzed by SEM and three-dimensional microscope.The results demonstrate that the structure,wear and corrosion resistance of PEO coatings with graphene are better than that of PEO coatings without graphene.The coating fabricated in the aluminate electrolyte with graphene exhibited the lowest roughness.The coated samples formed in silicate electrolyte with graphene displayed the thickest,densest and the most compact coating.It exhibited the best wear and corrosion resistance due to the incorporation mode of graphene in the coatings.The mechanism of graphene improving the wear and corrosion resistance of PEO coating was further discussed.In summary,the comprehensive performances of PEO coatings formed in silicate electrolyte on D16 T Al alloy are superior to that produced in aluminate electrolyte.