Selective hydrogenation is an important industrial catalytic process in chemical upgrading, where Pd-based catalysts are widely used because of their high hydrogenation activities. However, poor selectivity and short ...Selective hydrogenation is an important industrial catalytic process in chemical upgrading, where Pd-based catalysts are widely used because of their high hydrogenation activities. However, poor selectivity and short catalyst lifetime because of heavy coke formation have been major concerns. In this work, atomically dispersed Pd atoms were successfully synthesized on graphitic carbon nitride （g-C3N4） using atomic layer deposition. Aberration-corrected high-angle annular dark-field scanning transmission electron microscopy （HAADF-STEM） confirmed the dominant presence of isolated Pd atoms without Pd nanoparticle （NP） formation. During selective hydrogenation of acetylene in excess ethylene, the g-C3N4-supported Pd NP catalysts had strikingly higher ethylene selectivities than the conventional Pd/Al2O3 and Pd/SiO2 catalysts. In-situ X-ray photoemission spectroscopy revealed that the considerable charge transfer from the Pd NPs to g-C3N4 likely plays an important role in the catalytic performance enhancement. More impressively, the single-atom Pd1/C3N4 catalyst exhibited both higher ethylene selectivity and higher coking resistance. Our work demonstrates that the single-atom Pd catalyst is a promising candidate for improving both selectivity and coking-resistance in hydrogenation reactions.展开更多
Photoperiod responsiveness is a key factor limiting the geographic distribution of cultivated soybean and its wild ancestor.In particular,the genetic basis of the adaptation in wild soybean remains poorly understood.I...Photoperiod responsiveness is a key factor limiting the geographic distribution of cultivated soybean and its wild ancestor.In particular,the genetic basis of the adaptation in wild soybean remains poorly understood.In this study,by combining whole-genome resequencing and genome-wide association studies we identified a novel locus,Time of Flowering 5(Tof5),which promotes flowering and enhances adaptation to high latitudes in both wild and cultivated soybean.By genomic,genetic and transgenic analyses we showed that Tof5 en-codes a homolog of Arabidopsis thaliana FRUITFULL(FUL).Importantly,further analyses suggested that different alleles of Tof5 have undergone parallel selection.The Tof5H1 allele was strongly selected by humans after the early domestication of cultivated soybean,while Tof5H2 allele was naturally selected in wild soybean,and in each case facilitating adaptation to high latitudes.Moreover,we found that the key flowering repressor E1 suppresses the transcription of Tof5 by binding to its promoter.In turn,Tof5 physically associates with the promoters of two important FLOWERING LOCUS T(FT),FT2a and FT5a,to upregulate their transcription and promote flowering under long photoperiods.Collectively,ourfindings provide insights into how wild soybean adapted to high latitudes through natural selection and indicate that cultivated soybean underwent changes in the same gene but evolved a distinct allele that was artificially selected after domestication.展开更多
Inertinite maceral compositions of the Late Permian coals from three sections in the terrestrial and paralic settings of eastern Yunnan are analyzed in order to reveal the paleo-fire events and the atmospheric oxygen ...Inertinite maceral compositions of the Late Permian coals from three sections in the terrestrial and paralic settings of eastern Yunnan are analyzed in order to reveal the paleo-fire events and the atmospheric oxygen levels in the latest Permian. Although the macerals in the studied sections are generally dominated by vitrinite, the inertinite group makes up a considerable proportion. Its content increases upward from the beginning of the Late Permian to the coal seam near the Permian- Triassic boundary. Based on the microscopic features and the prevailing theory that inertinite is largely a by-product of paleo-fires, we suggest that the increasing upward trend of the inertinite abundance in the latest Permian could imply that the Late Permian peatland had suffered from frequent wildfires. Since ignition and burning depend on sufficient oxygen, a model-based calculation suggests that the 02 levels near the Wuchiapingian/Changhsingian boundary and the Permian-Triassic boundary are 27% and 28% respectively. This output adds supports to other discoveries made in the temporal marine and terrestrial sediments, and challenges the theories advocating hypoxia as a mechanism for the PermianTriassic boundary crisis.展开更多
Increased numbers of T follicular helper(Tfh)cells have been implicated in the development of autoimmune diseases including primary Sjögren’s syndrome(pSS),but how the Tfh cell response is regulated during autoi...Increased numbers of T follicular helper(Tfh)cells have been implicated in the development of autoimmune diseases including primary Sjögren’s syndrome(pSS),but how the Tfh cell response is regulated during autoimmune pathogenesis remains largely unclear.Here,we first found negative correlations between IL-10^(+)regulatory B(Breg)cell numbers and Tfh cell responses and disease activity in patients with pSS and mice with experimental Sjögren’s syndrome(ESS).Moreover,we detected high expression of IL-10 receptor on Tfh cells and their precursors in both humans and mice.In culture,IL-10 suppressed human and murine Tfh cell differentiation by promoting STAT5 phosphorylation.By using an adoptive transfer approach and two-photon live imaging,we found significantly increased numbers of Tfh cells with enhanced T cell homing into B cell follicles in the draining cervical lymph nodes of RAG-2−/−mice transferred with IL-10-deficient B cells during ESS development compared with those of RAG-2−/−mice transferred with wild-type B cells.In ESS mice,CD19^(+)CD1d^(hi)CD5^(+)Breg cells with decreased IL-10 production exhibited severely impaired suppressive effects on T cell proliferation.Consistently,CD19^(+)CD24^(+)CD38^(hi) Breg cells from pSS patients showed significantly reduced IL-10 production with defective inhibitory function in the suppression of autologous Tfh cell expansion.Furthermore,the adoptive transfer of IL-10-producing Breg cells markedly suppressed the Tfh cell response and ameliorated ESS progression in ESS mice.Together,these findings demonstrate a critical role for IL-10-producing Breg cells in restraining the effector Tfh cell response during pSS development.展开更多
The interaction between drug molecules and target proteins is the basis of pharmacological action.The pharmacodynamic mechanism of Chinese medicinal plants for chronic kidney disease(CKD) was studied by molecular dock...The interaction between drug molecules and target proteins is the basis of pharmacological action.The pharmacodynamic mechanism of Chinese medicinal plants for chronic kidney disease(CKD) was studied by molecular docking and complex network analysis.It was found that the interaction network of components-proteins of Chinese medicinal plants is different from the interaction network of components-proteins of drugs.The action mechanism of Chinese medicinal plants is different from that of drugs.We also found the interaction network of components-proteins of tonifying herbs is different from the interaction network of components-proteins of evil expelling herbs using complex network research approach.It illuminates the ancient classification theory of Chinese medicinal plants.This computational approach could identify the pivotal components of Chinese medicinal plants and their key target proteins rapidly.The results provide data for development of multi-component Chinese medicine.展开更多
基金Acknowledgements This work was supported by the Thousand Talents Plan, the National Natural Science Foundation of China （Nos. 21473169, 21673215, and 51402283）, the Fundamental Research Funds for the Central Universities （Nos. WK2060030017 and WK2060190026）, and the startup funds from the University of Science and Technology of China. This work was also supported by Hefei Science Center （No. 2015HSC-UP010）.
文摘Selective hydrogenation is an important industrial catalytic process in chemical upgrading, where Pd-based catalysts are widely used because of their high hydrogenation activities. However, poor selectivity and short catalyst lifetime because of heavy coke formation have been major concerns. In this work, atomically dispersed Pd atoms were successfully synthesized on graphitic carbon nitride （g-C3N4） using atomic layer deposition. Aberration-corrected high-angle annular dark-field scanning transmission electron microscopy （HAADF-STEM） confirmed the dominant presence of isolated Pd atoms without Pd nanoparticle （NP） formation. During selective hydrogenation of acetylene in excess ethylene, the g-C3N4-supported Pd NP catalysts had strikingly higher ethylene selectivities than the conventional Pd/Al2O3 and Pd/SiO2 catalysts. In-situ X-ray photoemission spectroscopy revealed that the considerable charge transfer from the Pd NPs to g-C3N4 likely plays an important role in the catalytic performance enhancement. More impressively, the single-atom Pd1/C3N4 catalyst exhibited both higher ethylene selectivity and higher coking resistance. Our work demonstrates that the single-atom Pd catalyst is a promising candidate for improving both selectivity and coking-resistance in hydrogenation reactions.
基金supported by the National Natural Science Foundation of China(grant nos.32090065 and 32001508 to L.D.,32090064 and 31725021 to F.K.,31930083 to B.L,31901568 to Q.C,32022062 to S.Lu.,32001502 to Y,Z)and also supported by the Major Program of Guangdong Basic and Applied FResearch(grant no.2019B030302006 to F.K.andB.L).
文摘Photoperiod responsiveness is a key factor limiting the geographic distribution of cultivated soybean and its wild ancestor.In particular,the genetic basis of the adaptation in wild soybean remains poorly understood.In this study,by combining whole-genome resequencing and genome-wide association studies we identified a novel locus,Time of Flowering 5(Tof5),which promotes flowering and enhances adaptation to high latitudes in both wild and cultivated soybean.By genomic,genetic and transgenic analyses we showed that Tof5 en-codes a homolog of Arabidopsis thaliana FRUITFULL(FUL).Importantly,further analyses suggested that different alleles of Tof5 have undergone parallel selection.The Tof5H1 allele was strongly selected by humans after the early domestication of cultivated soybean,while Tof5H2 allele was naturally selected in wild soybean,and in each case facilitating adaptation to high latitudes.Moreover,we found that the key flowering repressor E1 suppresses the transcription of Tof5 by binding to its promoter.In turn,Tof5 physically associates with the promoters of two important FLOWERING LOCUS T(FT),FT2a and FT5a,to upregulate their transcription and promote flowering under long photoperiods.Collectively,ourfindings provide insights into how wild soybean adapted to high latitudes through natural selection and indicate that cultivated soybean underwent changes in the same gene but evolved a distinct allele that was artificially selected after domestication.
基金supported by the National Natural Science Foundation of China(41030213)the Major National S&T Program of China(2011ZX05033-002 and 2011ZX05009-002)the Fundamental Research Funds for the Central Universities in China(2010YD09)
文摘Inertinite maceral compositions of the Late Permian coals from three sections in the terrestrial and paralic settings of eastern Yunnan are analyzed in order to reveal the paleo-fire events and the atmospheric oxygen levels in the latest Permian. Although the macerals in the studied sections are generally dominated by vitrinite, the inertinite group makes up a considerable proportion. Its content increases upward from the beginning of the Late Permian to the coal seam near the Permian- Triassic boundary. Based on the microscopic features and the prevailing theory that inertinite is largely a by-product of paleo-fires, we suggest that the increasing upward trend of the inertinite abundance in the latest Permian could imply that the Late Permian peatland had suffered from frequent wildfires. Since ignition and burning depend on sufficient oxygen, a model-based calculation suggests that the 02 levels near the Wuchiapingian/Changhsingian boundary and the Permian-Triassic boundary are 27% and 28% respectively. This output adds supports to other discoveries made in the temporal marine and terrestrial sediments, and challenges the theories advocating hypoxia as a mechanism for the PermianTriassic boundary crisis.
基金supported by grants from the National Natural Science Foundation of China(81771761 and 91842304)Chinese National Key Technology R&D Program,Ministry of Science and Technology(2017YFC0907601 and 2017YFC0907605)+2 种基金General Research Fund,Hong Kong Research Grants Council(17114515 and 17149716)Hong Kong Croucher Foundation(260960116)Sanming Project of Medicine in Shenzhen(SZSM201512019).
文摘Increased numbers of T follicular helper(Tfh)cells have been implicated in the development of autoimmune diseases including primary Sjögren’s syndrome(pSS),but how the Tfh cell response is regulated during autoimmune pathogenesis remains largely unclear.Here,we first found negative correlations between IL-10^(+)regulatory B(Breg)cell numbers and Tfh cell responses and disease activity in patients with pSS and mice with experimental Sjögren’s syndrome(ESS).Moreover,we detected high expression of IL-10 receptor on Tfh cells and their precursors in both humans and mice.In culture,IL-10 suppressed human and murine Tfh cell differentiation by promoting STAT5 phosphorylation.By using an adoptive transfer approach and two-photon live imaging,we found significantly increased numbers of Tfh cells with enhanced T cell homing into B cell follicles in the draining cervical lymph nodes of RAG-2−/−mice transferred with IL-10-deficient B cells during ESS development compared with those of RAG-2−/−mice transferred with wild-type B cells.In ESS mice,CD19^(+)CD1d^(hi)CD5^(+)Breg cells with decreased IL-10 production exhibited severely impaired suppressive effects on T cell proliferation.Consistently,CD19^(+)CD24^(+)CD38^(hi) Breg cells from pSS patients showed significantly reduced IL-10 production with defective inhibitory function in the suppression of autologous Tfh cell expansion.Furthermore,the adoptive transfer of IL-10-producing Breg cells markedly suppressed the Tfh cell response and ameliorated ESS progression in ESS mice.Together,these findings demonstrate a critical role for IL-10-producing Breg cells in restraining the effector Tfh cell response during pSS development.
基金supported by the Natural Science Foundation of Guangdong Province (9151063201000050)Foundation of Administration of Traditional Chinese Medicine of Guangdong Province (2008334)Major Program of Science and Technique Project of Guangdong Province (2009A030100006)
文摘The interaction between drug molecules and target proteins is the basis of pharmacological action.The pharmacodynamic mechanism of Chinese medicinal plants for chronic kidney disease(CKD) was studied by molecular docking and complex network analysis.It was found that the interaction network of components-proteins of Chinese medicinal plants is different from the interaction network of components-proteins of drugs.The action mechanism of Chinese medicinal plants is different from that of drugs.We also found the interaction network of components-proteins of tonifying herbs is different from the interaction network of components-proteins of evil expelling herbs using complex network research approach.It illuminates the ancient classification theory of Chinese medicinal plants.This computational approach could identify the pivotal components of Chinese medicinal plants and their key target proteins rapidly.The results provide data for development of multi-component Chinese medicine.
