Spontaneous polarization due to symmetry breaking in the transition metal ditellurides(MTe_(2))family exhibits intriguing sliding ferroelectricity.Although theoretical predictions of MTe_(2)ferroelectric metals with n...Spontaneous polarization due to symmetry breaking in the transition metal ditellurides(MTe_(2))family exhibits intriguing sliding ferroelectricity.Although theoretical predictions of MTe_(2)ferroelectric metals with noncentrosymmetric stacking have been reported,the realization of such polarization structure remains a challenge.Here,we demonstrate the synthesis of PtTe_(2)with non-centrosymmetric stacking layers,in contrast to bulk AA stacking,achieved within a scanning transmission electron microscope(STEM)by irradiating amorphous PtxTeythin flms with an electron beam probe.Cross-sectional STEM imaging combined with frst-principles calculations reveals that the diverse stacking confgurations due to an intralayerπ-stacking system break centrosymmetry in PtTe_(2),giving rise to the out-of-plane polarization.Three-dimensional atomic positions identifed by the atomic electron tomography method further demonstrate the local distortions associated with the non-centrosymmetric stacking layers in PtTe_(2).The understanding of the atomic origin of polarization in PtTe_(2)is of signifcant importance for developing devices that integrate ferroelectricity with metallicity.展开更多
Magmatism at continental margins is of great significance in understanding the continental rifting.We present a twodimensional P-wave velocity model derived from an ocean bottom seismometer experiment,conducted across...Magmatism at continental margins is of great significance in understanding the continental rifting.We present a twodimensional P-wave velocity model derived from an ocean bottom seismometer experiment,conducted across the middle northern continental margin of the South China Sea(SCS).The detailed velocity structures reveal significant heterogeneities extending from the continental shelf to the continent-ocean transition zone.The crust exhibits its greatest thickness below the continental shelf,measuring~23 km and gradually thins to~13 km at the distal margin.Furthermore,a narrow and distinct continent-ocean transition with only 40-km width is revealed.We also observe a high-velocity layer within the transition zone,reaching thickness of up to 4 km,characterized by P-wave velocities ranging from 7.0 km/s to 7.6 km/s in the lower crust.Based on the syn-rift melt generation using decompression melting model,we ascertain that syn-rift magmatism cannot fully account for the observed thick high-velocity layer.By integrating findings from previous geophysical and geochemical studies presenting extensive volcanic edifice on the seafloor at the northern margin,as well as ocean-island-basalt-type magmaticsamples in the SCS area,we propose that post-rifting magmatism associated with the Hainan Plume may have influenced theformation of the high-velocity lower crust within the transition zone and the northern margin of the SCS can thus be recognizedas magma-poor type margin.展开更多
文摘目的:运用网络药理学方法分析薏苡仁汤治疗膝骨关节炎的作用机制。方法:利用TCMSP数据库中的药动学参数,以口服生物利用度(oral bioavailability,OB)≥30%和药物相似性(drug-likeness,DL)≥0.18筛选薏仁汤的潜在有效成分和作用靶点。通过DrugBank、GeneCard、OMIM、TTD和PharmGkb数据库筛选膝骨关节炎靶基因;通过R语言软件Venn分析法得到疾病与药物共同靶基因。通过Cytoscape 3.8.0软件构建成分-靶点网络图。利用STRING平台构建蛋白-蛋白互作网络(protein-protein interactions,PPI),将得到的文本文件导入Cytoscape中,通过CytoNCA插件获取关键子网络模块。将上述交集基因通过R语言软件进行基因本体(gene ontology,GO)功能富集分析、京都基因和基因组百科全书(kyoto encyclopedia of genes and genomes,KEGG)通路富集分析。结果:共筛选出薏仁汤有效活性成分168个,包括谷甾醇、β-谷甾醇、香叶木素、汉黄芩素、槲皮素和豆甾醇等。有效作用靶点232个,药物疾病共同靶点129个,核心靶点包括JUN、MAPK3、STAT3、MAPK1、TP53、MAPK14、MYC、ESR1、MAPK8、AKT1、RELA、IL-6、TNF和EGFR。GO富集结果表明目标靶点参与的功能主要有细胞对化学应激的反应、对氧化应激的反应和对脂多糖的反应。KEGG主要富集在IL-17信号通路和TNF信号通路。结论:薏仁汤可能通过多成分、多靶点和多途径对膝骨关节炎发挥治疗作用。
基金supported by the National Key R&D Program of China(Grant Nos.2024YFA1208201,2022YFA1403000,and 2021YFA1400204)the National Natural Science Foundation of China(Grant Nos.52322311,12334001,52427802,12174432,12250710675,and 52461160301)the support from Guangdong Provincial Key Laboratory of Magnetoelectric Physics and Devices(Grant No.2022B1212010008)。
文摘Spontaneous polarization due to symmetry breaking in the transition metal ditellurides(MTe_(2))family exhibits intriguing sliding ferroelectricity.Although theoretical predictions of MTe_(2)ferroelectric metals with noncentrosymmetric stacking have been reported,the realization of such polarization structure remains a challenge.Here,we demonstrate the synthesis of PtTe_(2)with non-centrosymmetric stacking layers,in contrast to bulk AA stacking,achieved within a scanning transmission electron microscope(STEM)by irradiating amorphous PtxTeythin flms with an electron beam probe.Cross-sectional STEM imaging combined with frst-principles calculations reveals that the diverse stacking confgurations due to an intralayerπ-stacking system break centrosymmetry in PtTe_(2),giving rise to the out-of-plane polarization.Three-dimensional atomic positions identifed by the atomic electron tomography method further demonstrate the local distortions associated with the non-centrosymmetric stacking layers in PtTe_(2).The understanding of the atomic origin of polarization in PtTe_(2)is of signifcant importance for developing devices that integrate ferroelectricity with metallicity.
基金supported by the Guangdong Pearl River Talent Program(No.017TZ07Z066)the Second Tibetan Plateau Scientific Expedition and Research Program(No.2019QZKK0701)+4 种基金the Southern Marine Laboratory(Zhuhai)Innovative R&D Program(No.311021003)the National Natural Science Foundation of China(No.42106067)the Natural Science Foundation of Guangdong Province,China(No.2022A1515010090)Shanghai Sheshan National Geophysical Observatory(No.SSOP202102)Guangzhou Science and Technology Planning Project(No.202102020456).
文摘Magmatism at continental margins is of great significance in understanding the continental rifting.We present a twodimensional P-wave velocity model derived from an ocean bottom seismometer experiment,conducted across the middle northern continental margin of the South China Sea(SCS).The detailed velocity structures reveal significant heterogeneities extending from the continental shelf to the continent-ocean transition zone.The crust exhibits its greatest thickness below the continental shelf,measuring~23 km and gradually thins to~13 km at the distal margin.Furthermore,a narrow and distinct continent-ocean transition with only 40-km width is revealed.We also observe a high-velocity layer within the transition zone,reaching thickness of up to 4 km,characterized by P-wave velocities ranging from 7.0 km/s to 7.6 km/s in the lower crust.Based on the syn-rift melt generation using decompression melting model,we ascertain that syn-rift magmatism cannot fully account for the observed thick high-velocity layer.By integrating findings from previous geophysical and geochemical studies presenting extensive volcanic edifice on the seafloor at the northern margin,as well as ocean-island-basalt-type magmaticsamples in the SCS area,we propose that post-rifting magmatism associated with the Hainan Plume may have influenced theformation of the high-velocity lower crust within the transition zone and the northern margin of the SCS can thus be recognizedas magma-poor type margin.
