River runoff in the Arctic and the Tibetan Plateau(TP) change significantly in recent decades. However, the mechanisms of the physical processes of permafrost river runoff change remain uncertain across large scale. T...River runoff in the Arctic and the Tibetan Plateau(TP) change significantly in recent decades. However, the mechanisms of the physical processes of permafrost river runoff change remain uncertain across large scale. This study investigated the mainstreams and tributaries of main Arctic and TP rivers dominated by permafrost and assessed the linkage between hydrological regime change and permafrost. The results show that the effects of permafrost on river runoff are highly dependent on the permafrost coverage of a watershed. For the past decades, the majority of the Arctic and TP basins showed increased discharge, while all of the studied basins showed increased baseflow, with faster increasing speed than total discharge.Both total discharge and baseflow annual change rate(ΔQ and ΔBF) increased with permafrost coverage, indicating the increments of streamflow are enhanced with high permafrost coverage. Meanwhile, the annual change of precipitation showed weak connection with total discharge and baseflow change. The high permafrost coverage basins showed high annual maximum/minimum discharge ratio(Qmax/Qmin), while the Qmax/Qminchanged slightly in low permafrost cover basins. Our results highlight the importance of permafrost coverage on streamflow regime change for permafrost basins across the northern hemisphere. Due to these linkage between permafrost extent and runoff regime change and the increasing changes of permafrost, more attention should be paid to the change of hydrological processes in permafrost-underlain basins.展开更多
The Bub1 and BubR1 kinetochore proteins support proper chromosome segregation and mitotic checkpoint activity. Bub1 and BubR1 are paralogs with Bub1 being a kinase, while BubR1 localizes the PP2A-B56 protein phosphata...The Bub1 and BubR1 kinetochore proteins support proper chromosome segregation and mitotic checkpoint activity. Bub1 and BubR1 are paralogs with Bub1 being a kinase, while BubR1 localizes the PP2A-B56 protein phosphatase to kinetochores in humans. Whether this spatial separation of kinase and phosphatase activity is important is unclear as some organisms integrate both activities into one Bub protein. Here, we engineer human Bub1 and BubR1 proteins integrating kinase and phosphatase activities into one protein and show that these do not support normal mitotic progression. A Bub1–PP2A-B56 complex can support chromosome alignment but results in impairment of the checkpoint due to dephosphorylation of the Mad1 binding site in Bub1. Furthermore, a chimeric BubR1 protein containing the Bub1 kinase domain induces delocalized H2ApT120 phosphorylation, resulting in the reduction of centromeric hSgo2 and chromosome segregation errors. Collectively, these results argue that the spatial separation of kinase and phosphatase activities within the Bub complex is required for balancing its functions in the checkpoint and chromosome alignment.展开更多
CaO doped 0.5Na_(0.5)Bi_(0.5)TiO_(3)-0.5SrTiO_(3)(ST)were prepared by a traditional solid-reaction method under various sintering temperatures.X-ray diffraction(XRD),electron scanning microscopy(SEM),and electrical me...CaO doped 0.5Na_(0.5)Bi_(0.5)TiO_(3)-0.5SrTiO_(3)(ST)were prepared by a traditional solid-reaction method under various sintering temperatures.X-ray diffraction(XRD),electron scanning microscopy(SEM),and electrical measurements were employed to check the phases,microstructures,and energy storage properties.The doping of CaO can deeply affect the relaxation nature of NBT-ST ceramics.So the energy storage performance could be modified.Specially,sample with 1 at.%CaO exhibits a high energy storage density of 1.51 J/cm3.Any further details can be found within this study.展开更多
Ba_(0.9)Sr_(0.1)TiO_(3) ceramics with or without ZnO have been prepared by traditional solid state reaction method.The XRD analysis showed that the doped Zn^(2+) ions diffused into the BST crystal lattice,resulting in...Ba_(0.9)Sr_(0.1)TiO_(3) ceramics with or without ZnO have been prepared by traditional solid state reaction method.The XRD analysis showed that the doped Zn^(2+) ions diffused into the BST crystal lattice,resulting in the variation of dielectric properties.Especially the dielectric constant at Curie point decreased with doping ZnO content when it is lower than 0.5 mol%.Due to the promotion of sintering,doping ZnO can enhance the density of ceramics but increase grain size.However,ZnO is a kind of semiconductor and can lead to the decrease in electrical breakdown strength value.展开更多
基金This research was supported by the National Key Research and Development Program of China(2022YFC3201702)National Natural Science Foundationof China(U2240226,42201146)+1 种基金Sanjiangyuan National Park Joint Research Program of Chinese Academy of Sciences and The People's Government of Qinghai Province(LHZX-2020-10-3)Science and Technology Project of Sichuan Province(2022NSFSC1001).
基金supported by the Major Research Plan of the National Natural Science Foundation of China(Grant No.91547203)the National Natural Science Foundation of China(Grant No.41890821)the Strategic Priority Research Program of Chinese Academy of Sciences(Grant No.XDA20050102)
文摘River runoff in the Arctic and the Tibetan Plateau(TP) change significantly in recent decades. However, the mechanisms of the physical processes of permafrost river runoff change remain uncertain across large scale. This study investigated the mainstreams and tributaries of main Arctic and TP rivers dominated by permafrost and assessed the linkage between hydrological regime change and permafrost. The results show that the effects of permafrost on river runoff are highly dependent on the permafrost coverage of a watershed. For the past decades, the majority of the Arctic and TP basins showed increased discharge, while all of the studied basins showed increased baseflow, with faster increasing speed than total discharge.Both total discharge and baseflow annual change rate(ΔQ and ΔBF) increased with permafrost coverage, indicating the increments of streamflow are enhanced with high permafrost coverage. Meanwhile, the annual change of precipitation showed weak connection with total discharge and baseflow change. The high permafrost coverage basins showed high annual maximum/minimum discharge ratio(Qmax/Qmin), while the Qmax/Qminchanged slightly in low permafrost cover basins. Our results highlight the importance of permafrost coverage on streamflow regime change for permafrost basins across the northern hemisphere. Due to these linkage between permafrost extent and runoff regime change and the increasing changes of permafrost, more attention should be paid to the change of hydrological processes in permafrost-underlain basins.
基金supported by the National Natural Science Foundation of China(31970666)Taishan Scholar Project(tsqn201812054)from Shandong,China+3 种基金Work at the Novo Nordisk Foundation Center for Protein Research was supported by the grant NNF14CC0001J.N.is supported by grants from the Danish Cancer Society(R269-A15586-B17)Independent Research Fund Denmark(8021-00101B and 0134-00199B)Novo Nordisk Foundation(NNF20OC0065098).
文摘The Bub1 and BubR1 kinetochore proteins support proper chromosome segregation and mitotic checkpoint activity. Bub1 and BubR1 are paralogs with Bub1 being a kinase, while BubR1 localizes the PP2A-B56 protein phosphatase to kinetochores in humans. Whether this spatial separation of kinase and phosphatase activity is important is unclear as some organisms integrate both activities into one Bub protein. Here, we engineer human Bub1 and BubR1 proteins integrating kinase and phosphatase activities into one protein and show that these do not support normal mitotic progression. A Bub1–PP2A-B56 complex can support chromosome alignment but results in impairment of the checkpoint due to dephosphorylation of the Mad1 binding site in Bub1. Furthermore, a chimeric BubR1 protein containing the Bub1 kinase domain induces delocalized H2ApT120 phosphorylation, resulting in the reduction of centromeric hSgo2 and chromosome segregation errors. Collectively, these results argue that the spatial separation of kinase and phosphatase activities within the Bub complex is required for balancing its functions in the checkpoint and chromosome alignment.
基金supported by the National Natural Science Foundation of China(51502248,51672226)Fundamental Research Funds for the Central Universities(XDJK2017D013,XDJK2018B009,XDJK2018C002)National College Student innovation and Entrepreneurship Program of Southwest University(201810635001).
文摘CaO doped 0.5Na_(0.5)Bi_(0.5)TiO_(3)-0.5SrTiO_(3)(ST)were prepared by a traditional solid-reaction method under various sintering temperatures.X-ray diffraction(XRD),electron scanning microscopy(SEM),and electrical measurements were employed to check the phases,microstructures,and energy storage properties.The doping of CaO can deeply affect the relaxation nature of NBT-ST ceramics.So the energy storage performance could be modified.Specially,sample with 1 at.%CaO exhibits a high energy storage density of 1.51 J/cm3.Any further details can be found within this study.
基金The work is supported by"Fundamental Research Funds for the Central Universities"(XDJK2016E010,XDJK2015C001 and SWU113054).
文摘Ba_(0.9)Sr_(0.1)TiO_(3) ceramics with or without ZnO have been prepared by traditional solid state reaction method.The XRD analysis showed that the doped Zn^(2+) ions diffused into the BST crystal lattice,resulting in the variation of dielectric properties.Especially the dielectric constant at Curie point decreased with doping ZnO content when it is lower than 0.5 mol%.Due to the promotion of sintering,doping ZnO can enhance the density of ceramics but increase grain size.However,ZnO is a kind of semiconductor and can lead to the decrease in electrical breakdown strength value.