We investigate the energy bands,magnetism,and superconductivity of bilayer octagraphene with A-A stackingunder a perpendicular electric field.A tight-binding model is used to analyze the band structure of the system.T...We investigate the energy bands,magnetism,and superconductivity of bilayer octagraphene with A-A stackingunder a perpendicular electric field.A tight-binding model is used to analyze the band structure of the system.The doubling of the unit cell results in each band of the single layer splitting into two.We find that applyinga perpendicular electric field increases the band splitting.As the electric field strength increases,the nestingof the Fermi surface(FS)weakens,eventually disrupting the antiferromagnetic order,and bilayer octagrapheneexhibits superconductivity.Spin fluctuations can induce unconventional superconductivity with s±-wave pairing.Applying a perpendicular electric field to bilayer octagraphene parent weakens the nesting of the FS,ultimatelykilling the spin-density-wave(SDW)ordered state and transitioning it into the superconducting state,whichworks as a doping effect.We use the random-phase approximation approach to obtain the pairing eigenvaluesand pairing symmetries of the perpendicular electric field-tuned bilayer octagraphene in the weak coupling limit.By tuning the strength of the perpendicular electric field,the critical interaction strength for SDW order can bemodified,which in turn may promote the emergence of unconventional superconductivity.展开更多
Although cartilage tissue engineering has been developed for decades, it is still unclear whether angio- genesis was the accompaniment of chondrogenesis in cartilage regeneration. This study aimed to explore the proce...Although cartilage tissue engineering has been developed for decades, it is still unclear whether angio- genesis was the accompaniment of chondrogenesis in cartilage regeneration. This study aimed to explore the process of anti-angiogenesis during cartilage regenerative progress in cartilage repair extracellular matrix （ECM） materials under Hypoxia. C3H10T1/2 cell line, seeded as pellet or in ECM materials, was added with chondrogenic medium or DMEM medium for 21 days under hypoxia or normoxia environment. Genes and miRNAs related with chondrogenesis and angiogenesis were detected by RT-qPCR technique on Days 7, 14, and 21. Dual-luciferase report system was used to explore the regulating roles of miRNAs on angiogenesis. Results showed that the chondrogenic medium promotes chondrogenesis both in pellet and ECM materials culture. HIF1α was up-regulated under hypoxia compared with normoxia （P 〈 0.05）. Meanwhile, hypoxia enhanced chondrogenesis, miR-140-Sp exhibited higher expression while miR-146b exhibited lower expression. The chondrogenic phenotype was more stabilized in the ECM materials in chondrogenic medium than DMEM medium, with lower VEGFα expression even under hypoxia. Dual-luciferase report assays demonstrated that miR-140-5p directly targets VEGFct by binding its 3＇- UTR. Taken together, chondrogenic cytokines, ECM materials and hypoxia synergistically promoted chondrogenesis and inhibited angiogenesis, miR-140-5p olaved an imnortant role in this process.展开更多
A new two-dimensional allotrope of carbon known as biphenylene has been synthesized.Building on previous research investigating the superconductivity of octagraphene with a square-octagon structure,we conduct a system...A new two-dimensional allotrope of carbon known as biphenylene has been synthesized.Building on previous research investigating the superconductivity of octagraphene with a square-octagon structure,we conduct a systematic study on possible superconductivity of biphenylene with partial square-octagon structure.First-principle calculations are used to fit the tight-binding model of the material and to estimate its superconductivity.We find that the conventional superconducting transition temperature Tc based on electron-phonon interaction is 3.02 K,while the unconventional Tc primarily caused by spin fluctuation is 1.7 K.We hypothesize that the remaining hexagonal C6structure of biphenylene may not be conducive to the formation of perfect Fermi nesting,leading to a lower Tc.The superconducting properties of this material fall between those of graphene and octagraphene,and it lays a foundation for achieving high-temperature superconductivity in carbon-based materials.展开更多
基金supported by the National Key R&D Program of China(Grant No.2022YFA1402802)the National Natural Science Foundation of China(Grant Nos.12494591 and 92165204)+4 种基金the Leading Talent Program of Guangdong Special Projects(Grant No.201626003)the Guangdong Provincial Key Laboratory of Magnetoelectric Physics and Devices(Grant No.2022B1212010008)the Research Center for Magnetoelectric Physics of Guangdong Province(Grant No.2024B0303390001)the Guangdong Provincial Quantum Science Strategic Initiative(Grant No.GDZX2401010)supported by the National Natural Science Foundation of China(Grant Nos.12234016 and 12074031)。
文摘We investigate the energy bands,magnetism,and superconductivity of bilayer octagraphene with A-A stackingunder a perpendicular electric field.A tight-binding model is used to analyze the band structure of the system.The doubling of the unit cell results in each band of the single layer splitting into two.We find that applyinga perpendicular electric field increases the band splitting.As the electric field strength increases,the nestingof the Fermi surface(FS)weakens,eventually disrupting the antiferromagnetic order,and bilayer octagrapheneexhibits superconductivity.Spin fluctuations can induce unconventional superconductivity with s±-wave pairing.Applying a perpendicular electric field to bilayer octagraphene parent weakens the nesting of the FS,ultimatelykilling the spin-density-wave(SDW)ordered state and transitioning it into the superconducting state,whichworks as a doping effect.We use the random-phase approximation approach to obtain the pairing eigenvaluesand pairing symmetries of the perpendicular electric field-tuned bilayer octagraphene in the weak coupling limit.By tuning the strength of the perpendicular electric field,the critical interaction strength for SDW order can bemodified,which in turn may promote the emergence of unconventional superconductivity.
基金supported by the National Basic Research Program of China(973 Program,No.2012CB619100)the National Natural Science Foundation of China(Nos.31430030,0731001,and 81071512)+1 种基金the Natural Science Foundation of Guangdong Province(No.2014A030310466)the China Scholarship Council
文摘Although cartilage tissue engineering has been developed for decades, it is still unclear whether angio- genesis was the accompaniment of chondrogenesis in cartilage regeneration. This study aimed to explore the process of anti-angiogenesis during cartilage regenerative progress in cartilage repair extracellular matrix （ECM） materials under Hypoxia. C3H10T1/2 cell line, seeded as pellet or in ECM materials, was added with chondrogenic medium or DMEM medium for 21 days under hypoxia or normoxia environment. Genes and miRNAs related with chondrogenesis and angiogenesis were detected by RT-qPCR technique on Days 7, 14, and 21. Dual-luciferase report system was used to explore the regulating roles of miRNAs on angiogenesis. Results showed that the chondrogenic medium promotes chondrogenesis both in pellet and ECM materials culture. HIF1α was up-regulated under hypoxia compared with normoxia （P 〈 0.05）. Meanwhile, hypoxia enhanced chondrogenesis, miR-140-Sp exhibited higher expression while miR-146b exhibited lower expression. The chondrogenic phenotype was more stabilized in the ECM materials in chondrogenic medium than DMEM medium, with lower VEGFα expression even under hypoxia. Dual-luciferase report assays demonstrated that miR-140-5p directly targets VEGFct by binding its 3＇- UTR. Taken together, chondrogenic cytokines, ECM materials and hypoxia synergistically promoted chondrogenesis and inhibited angiogenesis, miR-140-5p olaved an imnortant role in this process.
基金supported by the National Key R&D Program of China(Grant Nos.2018YFA0306001 and 2022YFA1402802)the National Natural Science Foundation of China(Grant Nos.92165204,11974431,and 11974432)+2 种基金the Natural Science Foundation of Hebei Province(Grant No.A2021203010)Shenzhen International Quantum Academy(Grant No.SIQA202102)the Leading Talent Program of Guangdong Special Projects(Grant No.201626003)。
文摘A new two-dimensional allotrope of carbon known as biphenylene has been synthesized.Building on previous research investigating the superconductivity of octagraphene with a square-octagon structure,we conduct a systematic study on possible superconductivity of biphenylene with partial square-octagon structure.First-principle calculations are used to fit the tight-binding model of the material and to estimate its superconductivity.We find that the conventional superconducting transition temperature Tc based on electron-phonon interaction is 3.02 K,while the unconventional Tc primarily caused by spin fluctuation is 1.7 K.We hypothesize that the remaining hexagonal C6structure of biphenylene may not be conducive to the formation of perfect Fermi nesting,leading to a lower Tc.The superconducting properties of this material fall between those of graphene and octagraphene,and it lays a foundation for achieving high-temperature superconductivity in carbon-based materials.
