To improve the understandings on regional climatic effects of past human-induced land cover changes,the surface albedo changes caused by conversions from natural vegetation to cropland were estimated across northeaste...To improve the understandings on regional climatic effects of past human-induced land cover changes,the surface albedo changes caused by conversions from natural vegetation to cropland were estimated across northeastern China over the last 300 years,and its climatic effects were simulated by using the Weather Research and Forecasting (WRF) model.Essential natural vegetation records compiled from historical documents and regional optimal surface albedo dataset were used.The results show that the surface albedo decreased by 0.01-0.03 due to conversions from grassland to cropland in the Northeast China Plain and it increased by 0.005-0.015 due to conversions from forests to cropland in the surrounding mountains.As a consequence,in the Northeast China Plain,the surface net radiation increased by 4-8 W/m 2,2-5 W/m 2,and 1-3 W/m 2,and the climate was therefore warmed by 0.1℃-0.2℃、0.1℃-0.2℃、 0.1℃-0.3 ℃ in the spring,autumn and winter,respectively.In the surrounding mountain area,the net radiation decreased by less than 1.5 W/m 2,and the climate was therefore cooled too slight to be detected.In summer,effects of surface albedo changes on climate were closely associated with moisture dynamics,such as evapotranspiration and cloud,instead of being merely determined by surface radiation budget.The simulated summer climatic effects have large uncertainties.These findings demonstrate that surface albedo changes resulted in warming climate effects in the non-rainy seasons in Northeast China Plain through surface radiation processes while the climatic effects in summer could hardly be concluded so far.展开更多
Incorporating private and working lands into protected area networks could mitigate the isolation state of protected areas(PAs) and improve the efficiency of conservation.But how to select patches of land for conserva...Incorporating private and working lands into protected area networks could mitigate the isolation state of protected areas(PAs) and improve the efficiency of conservation.But how to select patches of land for conservation is still a troublesome issue.In this study, the MaxEnt model and irreplaceability index were applied to guide marsh conservation in the Nenjiang River Basin, Northeast China.According to the high accuracy of the MaxEnt model predictions(i.e., the average AUC value = 0.933), the Wuyuer River and Zhalong marshes in the downstream reaches of Wuyuer River are the optimal habitat for the Red-crowned crane and migratory waterfowls.There are 22 marsh patches selected by the patch irreplaceability index for conservation, of which 12 patches had been included in the current network of protected areas.The other 10 patches of marsh(amounting to 1096 km^2) far from human disturbances with high NDVI(up to 0.8) and close distance to water(less than 100 m), which are excluded from the existing network of PAs, should be implemented conservation easement programs to improve the protection efficiency of conservation.Specifically, the marshes at Taha, Tangchi, and Lamadian should be given priority for conservation and restoration to reintroduce migratory waterfowls, as this would lessen the current isolation state of the Zhalong National Nature Reserve.展开更多
目的:研究细胞骨架相关蛋白2(cytoskeleton-associated protein 2,CKAP2)对肝癌细胞的增殖、凋亡和迁移的作用及其机制。方法:培养正常肝细胞L02和肝癌细胞系HepG2,Huh7和SMMC-7721。采用实时PCR和蛋白质印迹法检测CKAP2的表达水平。进...目的:研究细胞骨架相关蛋白2(cytoskeleton-associated protein 2,CKAP2)对肝癌细胞的增殖、凋亡和迁移的作用及其机制。方法:培养正常肝细胞L02和肝癌细胞系HepG2,Huh7和SMMC-7721。采用实时PCR和蛋白质印迹法检测CKAP2的表达水平。进一步将HepG2细胞分为对照(Control)组、阴性对照(NC)组和沉默CKAP2(siCKAP2)组。NC组和siCKAP2组细胞分别转染siControl和siCKAP2。采用CKK-8法检测细胞活性,BrdU掺入法检测细胞增殖,凋亡试剂盒检测细胞凋亡,transwell实验检测细胞的迁移和侵袭。采用蛋白质印迹法检测cleavedcaspase 3,Bax,E-cadherin,N-cadherin,Vimentin以及磷酸化的Janus激酶2(Janus kinase 2,JAK2)和磷酸化的信号转导和转录激活因子3(signal transducer and activator of transcription 3,STAT3)的蛋白质表达水平。结果:与正常肝细胞L02比较,CKAP2在肝癌细胞系HepG2,Huh7和SMMC-7721中的表达显著上调(均P<0.05)。与NC组比较,siCKAP2组细胞活性和增殖率显著下降(均P<0.05);细胞凋亡率升高,cleaved-caspase 3和Bax的蛋白质表达水平显著上调(均P<0.05);细胞迁移和侵袭显著减少(均P<0.05);E-cadherin蛋白质表达水平显著上调,Vimentin,Ncadherin,磷酸化的JAK2和磷酸化的STAT3的蛋白质表达水平显著下调(均P<0.05)。结论:沉默CKAP2基因抑制肝癌细胞的增殖、迁移和侵袭,促进其凋亡,JAK2/STAT3信号通路可能参与这些过程。展开更多
A 2.45 GHz electron cyclotron resonance intense proton source and a low energy beam transport line with dual-Glaser lens were designed and fabricated by Institute of Modern Physics for a compact pulsed hadron source a...A 2.45 GHz electron cyclotron resonance intense proton source and a low energy beam transport line with dual-Glaser lens were designed and fabricated by Institute of Modern Physics for a compact pulsed hadron source at Tsinghua. The intense proton beams extracted from the ion source are transported through the transport line to match the downstream radio frequency quadrupole accelerator. Particle-in-cell code BEAMPATH was used to carry out the beam transport simulations and optimize the magnetic field structures of the transport line. Emittance growth due to space charge and spherical aberrations of the Glaser lens were studied in both theory and simulation. The results show that narrow beam has smaller aberrations and better beam quality through the transport line. To better match the radio frequency quadrupole accelerator, a shorter transport line is desired with sufficient space charge neutralization.展开更多
基金Under the auspices of National Natural Science Foundation of China(No.41001122)China Global Change Research Program(No.2010CB950102,2010CB950903)State-Sponsored Study Abroad Programs from China Scholarship Council(No.2007U21061)
文摘To improve the understandings on regional climatic effects of past human-induced land cover changes,the surface albedo changes caused by conversions from natural vegetation to cropland were estimated across northeastern China over the last 300 years,and its climatic effects were simulated by using the Weather Research and Forecasting (WRF) model.Essential natural vegetation records compiled from historical documents and regional optimal surface albedo dataset were used.The results show that the surface albedo decreased by 0.01-0.03 due to conversions from grassland to cropland in the Northeast China Plain and it increased by 0.005-0.015 due to conversions from forests to cropland in the surrounding mountains.As a consequence,in the Northeast China Plain,the surface net radiation increased by 4-8 W/m 2,2-5 W/m 2,and 1-3 W/m 2,and the climate was therefore warmed by 0.1℃-0.2℃、0.1℃-0.2℃、 0.1℃-0.3 ℃ in the spring,autumn and winter,respectively.In the surrounding mountain area,the net radiation decreased by less than 1.5 W/m 2,and the climate was therefore cooled too slight to be detected.In summer,effects of surface albedo changes on climate were closely associated with moisture dynamics,such as evapotranspiration and cloud,instead of being merely determined by surface radiation budget.The simulated summer climatic effects have large uncertainties.These findings demonstrate that surface albedo changes resulted in warming climate effects in the non-rainy seasons in Northeast China Plain through surface radiation processes while the climatic effects in summer could hardly be concluded so far.
基金Under the auspices of National Key Research and Development Program of China(No.2016YFA0600401)the Key Research Program of Frontier Sciences from Chinese Academy of Sciences+1 种基金Fundamental Research Funds in Heilongjiang Provincial Universities(No.135209252,135309359)the Philosophy and Social Sciences Research Plan of Heilongjiang Province(No.16JLC01)
文摘Incorporating private and working lands into protected area networks could mitigate the isolation state of protected areas(PAs) and improve the efficiency of conservation.But how to select patches of land for conservation is still a troublesome issue.In this study, the MaxEnt model and irreplaceability index were applied to guide marsh conservation in the Nenjiang River Basin, Northeast China.According to the high accuracy of the MaxEnt model predictions(i.e., the average AUC value = 0.933), the Wuyuer River and Zhalong marshes in the downstream reaches of Wuyuer River are the optimal habitat for the Red-crowned crane and migratory waterfowls.There are 22 marsh patches selected by the patch irreplaceability index for conservation, of which 12 patches had been included in the current network of protected areas.The other 10 patches of marsh(amounting to 1096 km^2) far from human disturbances with high NDVI(up to 0.8) and close distance to water(less than 100 m), which are excluded from the existing network of PAs, should be implemented conservation easement programs to improve the protection efficiency of conservation.Specifically, the marshes at Taha, Tangchi, and Lamadian should be given priority for conservation and restoration to reintroduce migratory waterfowls, as this would lessen the current isolation state of the Zhalong National Nature Reserve.
文摘目的:研究细胞骨架相关蛋白2(cytoskeleton-associated protein 2,CKAP2)对肝癌细胞的增殖、凋亡和迁移的作用及其机制。方法:培养正常肝细胞L02和肝癌细胞系HepG2,Huh7和SMMC-7721。采用实时PCR和蛋白质印迹法检测CKAP2的表达水平。进一步将HepG2细胞分为对照(Control)组、阴性对照(NC)组和沉默CKAP2(siCKAP2)组。NC组和siCKAP2组细胞分别转染siControl和siCKAP2。采用CKK-8法检测细胞活性,BrdU掺入法检测细胞增殖,凋亡试剂盒检测细胞凋亡,transwell实验检测细胞的迁移和侵袭。采用蛋白质印迹法检测cleavedcaspase 3,Bax,E-cadherin,N-cadherin,Vimentin以及磷酸化的Janus激酶2(Janus kinase 2,JAK2)和磷酸化的信号转导和转录激活因子3(signal transducer and activator of transcription 3,STAT3)的蛋白质表达水平。结果:与正常肝细胞L02比较,CKAP2在肝癌细胞系HepG2,Huh7和SMMC-7721中的表达显著上调(均P<0.05)。与NC组比较,siCKAP2组细胞活性和增殖率显著下降(均P<0.05);细胞凋亡率升高,cleaved-caspase 3和Bax的蛋白质表达水平显著上调(均P<0.05);细胞迁移和侵袭显著减少(均P<0.05);E-cadherin蛋白质表达水平显著上调,Vimentin,Ncadherin,磷酸化的JAK2和磷酸化的STAT3的蛋白质表达水平显著下调(均P<0.05)。结论:沉默CKAP2基因抑制肝癌细胞的增殖、迁移和侵袭,促进其凋亡,JAK2/STAT3信号通路可能参与这些过程。
基金Supported by the Compact Pulsed Hadron Source (CPHS) project at Tsinghua UniversityNational Nature Science foundation of China (11027508)
文摘A 2.45 GHz electron cyclotron resonance intense proton source and a low energy beam transport line with dual-Glaser lens were designed and fabricated by Institute of Modern Physics for a compact pulsed hadron source at Tsinghua. The intense proton beams extracted from the ion source are transported through the transport line to match the downstream radio frequency quadrupole accelerator. Particle-in-cell code BEAMPATH was used to carry out the beam transport simulations and optimize the magnetic field structures of the transport line. Emittance growth due to space charge and spherical aberrations of the Glaser lens were studied in both theory and simulation. The results show that narrow beam has smaller aberrations and better beam quality through the transport line. To better match the radio frequency quadrupole accelerator, a shorter transport line is desired with sufficient space charge neutralization.
