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CrO_(2)单层:一种兼具高居里温度和半金属特性的二维铁磁体

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物理学报 2024年第10期73卷 278-286页

作者：刘冰心李宗良山东师范大学物理与电子科学学院济南250358

半金属铁磁体在费米能级附近具有特殊的能带结构,电子极化率可高达100%,在自旋电子学领域备受关注.但是大部分铁磁半金属材料的居里温度远低于室温,这大大限制了二维铁磁半金属材料的实际应用.因此寻找具有高居里温度的半金属铁磁体是... 详细信息

半金属铁磁体在费米能级附近具有特殊的能带结构,电子极化率可高达100%,在自旋电子学领域备受关注.但是大部分铁磁半金属材料的居里温度远低于室温,这大大限制了二维铁磁半金属材料的实际应用.因此寻找具有高居里温度的半金属铁磁体是一项具有挑战性的工作.本文基于密度泛函理论框架下的第一性原理方法,研究了过渡金属氧化物CrO_(2)单层的晶体结构、电子特性、基态磁性和铁磁相变.形成能计算、声子谱计算和分子动力学模拟表明CrO_(2)具有动力学稳定性和热稳定性,弹性常数计算表明CrO_(2)具有力学稳定性.基于GGA+U和SCAN方法的自旋极化计算表明CrO_(2)单层的磁基态是铁磁态.采用GGA+U方法计算了CrO_(2)的电子态密度和能带结构,CrO_(2)被确认为一种宽带隙的二维铁磁半金属.运用蒙特卡罗模拟方法求解Heisenberg模型,得到CrO_(2)单层是一种居里温度超过400 K的二维本征半金属铁磁体.CrO_(2)单层的高居里温度在二维铁磁材料中并不多见,在半金属材料中更为稀少,这将使它成为制备自旋电子器件和研究自旋量子效应的理想材料.

关键词：过渡金属氧化物二维铁磁半金属居里温度第一性原理

Anisotropic spin transport and photoresponse characteristics detected by tip movement in magnetic single-molecule junction

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Chinese Physics B 2024年第4期33卷 640-648页

作者：陈登辉羊志付新宇秦申奥严岩王传奎李宗良邱帅 Shandong Key Laboratory of Medical Physics and Image Processing&Shandong Provincial Engineering and Technical Center of Light Manipulations School of Physics and ElectronicsShandong Normal UniversityJinan 250358China

Orientation-dependent transport properties induced by anisotropic molecules are enticing in single-molecule junctions.Here,using the first-principles method,we theoretically investigate spin transport properties and photoresponse characteristics in trimesic acid magnetic single-molecule junctions with different molecular adsorption orientations and electrode contact sites.The transport calculations indicate that a single-molecule switch and a significant enhancement of spin transport and photoresponse can be achieved when the molecular adsorption orientation changes from planar geometry to upright geometry.The maximum spin polarization of current and photocurrent in upright molecular junctions exceeds 90%.Moreover,as the Ni tip electrode moves,the tunneling magnetoresistance of upright molecular junctions can be increased to 70%.The analysis of the spin-dependent PDOS elucidates that the spinterfaces between organic molecule and ferromagnetic electrodes are modulated by molecular adsorption orientation,where the molecule in upright molecular junctions yields higher spin polarization.Our theoretical work paves the way for designing spintronic devices and optoelectronic devices with anisotropic functionality base on anisotropic molecules.

关键词： molecular spintronics spin polarization tunneling magnetoresistance photocurrent single-molecule junctions

Patterns and drivers of avian taxonomic and phylogenetic beta diversity in China vary across geographical backgrounds and dispersal abilities

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Zoological Research 2024年第1期45卷 125-135页

作者： Jian-Chao liang Zhi-Feng Ding Chun-Lin Li Yi-Ming Hu Zhi-Xin Zhou Gan-Wen Lie Xiao-Nan Niu Wen-Bin Huang hui-Jian Hu Xing-Feng Si Guangdong Key Laboratory of Animal Conservation and Resource Utilization Guangdong Public Laboratory of Wild Animal Conservation and UtilizationInstitute of ZoologyGuangdong Academy of SciencesGuangzhouGuangdong 510260China School of Resources and Environmental Engineering Anhui UniversityHefeiAnhui 230601China Guangdong Eco-Engineering Polytechnic GuangzhouGuangdong 510520China huizhou Institute of Forestry(huizhou Botanical Garden Management Service Center) HuizhouGuangdong 516001China Administration of National Nature Reserve for Marine Ecology of Guangdong Nanpeng Islands ShantouGuangdong 515900China Zhejiang Zhoushan Archipelago Observation and Research Station Institute of Eco-ChongmingZhejiang Tiantong Forest Ecosystem National Observation and Research StationSchool of Ecological and Environmental SciencesEast China Normal UniversityShanghai 200241China

Geographical background and dispersal ability may strongly influence assemblage dissimilarity;however,these aspects have generally been overlooked in previous large-scale beta diversity studies.Here,we examined whether the patterns and drivers of taxonomic beta diversity(TBD)and phylogenetic beta diversity(PBD)of breeding birds in China vary across(1)regions on both sides of the Hu Line,which demarcates China’s topographical,climatic,economic,and social patterns,and(2)species with different dispersal ability.TBD and PBD were calculated and partitioned into turnover and nestedness components using a moving window approach.Variables representing climate,habitat heterogeneity,and habitat quality were employed to evaluate the effects of environmental filtering.Spatial distance was considered to assess the impact of dispersal limitation.Variance partitioning analysis was applied to assess the relative roles of these variables.In general,the values of TBD and PBD were high in mountainous areas and were largely determined by environmental filtering.However,different dominant environmental filters on either side of the Hu Line led to divergent beta diversity patterns.Specifically,climate-driven species turnover and habitat heterogeneity-related species nestedness dominated the regions east and west of the line,respectively.Additionally,bird species with stronger dispersal ability were more susceptible to environmental filtering,resulting in more homogeneous assemblages.Our results indicated that regions with distinctive geographical backgrounds may present different ecological factors that lead to divergent assemblage dissimilarity patterns,and dispersal ability determines the response of assemblages to these ecological factors.Identifying a single universal explanation for the observed pattern without considering these aspects may lead to simplistic or incomplete conclusions.Consequently,a comprehensive understanding of large-scale beta diversity patterns and effective planning of conservation strategies necessitate the

关键词： Beta diversity Environmental filtering Dispersal limitation Hu Line Species dispersal ability Breeding birds

Core-shell nanoparticle enhanced Raman spectroscopy in situ probing the composition and evolution of interfacial species on PtCo surfaces

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Nano Research 2024年第6期17卷 4687-4692页

作者： Jing Liu Han-liang Zhong Xiangyu Li Mu-Fei Yue Wei-Min Yang Xueqiu You Jing-Hua Tian Yao-hui Wang Jian-Feng Li Fujian Provincial Key Laboratory of Oceanic Information Perception and Intelligent Processing School of Ocean Information EngineeringJimei UniversityXiamen 361021China College of Chemistry Fuzhou UniversityFuzhou 350108China State Key Laboratory of Physical Chemistry of Solid Surfaces MOE Key Laboratory of Spectrochemical Analysis and InstrumentationiChEMCollege of Chemistry and Chemical EngineeringCollege of MaterialsCollege of EnergyXiamen UniversityXiamen 361005China Innovation Laboratory for Sciences and Technologies of Energy Materials of Fujian Province(IKKEM) Xiamen 361005China Shenzhen Research Institute of Xiamen University Shenzhen 518000China

The composition and evolution of interfacial species play a key role during electrocatalytic process.Unveiling the structural evolution and intermediate during catalytic process by in situ characterization can shed new light on the electrocatalytic reaction mechanism and develop highly efficient catalyst.However,directly probing the interfacial species is extremely difficult for most spectroscopic techniques due to complicated interfacial environment and ultra-low surface concentration.Herein,electrochemical core-shell nanoparticle enhanced Raman spectroscopy is utilized to probe the composition and evolution processes of interfacial species on Au@Pt,Au@Co,and Au@PtCo core-shell nanoparticle surfaces.The spectral evidences of interfacial intermediates including hydroxide radical(OH*),superoxide ion(O_(2)^(−)),as well as metal oxide species are directly captured by in situ Raman spectroscopy,which are further confirmed by the both isotopic experiment and density functional theory calculation.These results provide a mechanistic guideline for the rational design of highly efficient electrocatalysts.

关键词： in situ Raman core-shell nanoparticle PtCo interfacial species composition and evolution

Genetic lineage tracing identifies adaptive mechanisms of pancreatic islet β cells in various mouse models of diabetes with distinct age of initiation

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Science China(Life Sciences) 2024年第3期67卷 504-517页

作者： Qi Fu Yu Qian Hemin Jiang Yunqiang He Hao Dai Yang Chen Zhiqing Xia Yucheng liang Yuncai Zhou Rui Gao Shuai Zheng hui Lv Min Sun Kuanfeng Xu Tao Yang Department of Endocrinology the First Affiliated Hospital of Nanjing Medical UniversityNanjing 210029China

During the pathogenesis of type 1 diabetes(T1D) and type 2 diabetes(T2D), pancreatic islets, especially the β cells, face significant challenges. These insulin-producing cells adopt a regeneration strategy to compensate for the shortage of insulin, but the exact mechanism needs to be defined. High-fat diet(HFD) and streptozotocin(STZ) treatment are well-established models to study islet damage in T2D and T1D respectively. Therefore, we applied these two diabetic mouse models, triggered at different ages, to pursue the cell fate transition of isletβ cells. Cre-LoxP systems were used to generate islet cell type-specific(α, β, or δ) green fluorescent protein(GFP)-labeled mice for genetic lineage tracing, thereinto β-cell GFP-labeled mice were tamoxifen induced. Single-cell RNA sequencing(scRNA-seq) was used to investigate the evolutionary trajectories and molecular mechanisms of the GFP-labeled β cells in STZ-treated mice. STZ-induced diabetes caused extensive dedifferentiation of β cells and some of which transdifferentiated into α or δ cells in both youth-and adulthood-initiated mice while this phenomenon was barely observed in HFD models. β cells in HFD mice were expanded via self-replication rather than via transdifferentiation from α or δ cells, in contrast, α or δ cells were induced to transdifferentiate into β cells in STZ-treated mice(both youthand adulthood-initiated). In addition to the re-dedifferentiation of β cells, it is also highly likely that these “α or δ” cells transdifferentiated from pre-existing β cells could also re-trans-differentiate into insulin-producing β cells and be beneficial to islet recovery. The analysis of ScRNA-seq revealed that several pathways including mitochondrial function, chromatin modification, and remodeling are crucial in the dynamic transition of β cells. Our findings shed light on how islet β cells overcome the deficit of insulin and the molecular mechanism of islet recovery in T1D and T2D pathogenesis.

关键词： islet regeneration lineage tracing high fat diet(HFD) streptozotocin(STZ)

Oscillatory Dynamics of Heterogeneous Stem Cell Regeneration

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Communications on Applied Mathematics and Computation 2024年第1期6卷 431-453页

作者： Xiyin liang Jinzhi Lei School of Mathematical Sciences Center for Applied MathematicsTiangong UniversityTianjin300387China

Stem cell regeneration is an essential biological process in the maintenance of tissue homeostasis;dysregulation of stem cell regeneration may result in dynamic diseases that show oscillations in cell numbers.Cell heterogeneity and plasticity are necessary for the dynamic equilibrium of tissue homeostasis;however,how these features may affect the oscillatory dynamics of the stem cell regeneration process remains poorly understood.Here,based on a mathematical model of heterogeneous stem cell regeneration that includes cell heterogeneity and random transition of epigenetic states,we study the conditions to have oscillation solutions through bifurcation analysis and numerical simulations.Our results show various model system dynamics with changes in different parameters associated with kinetic rates,cellular heterogeneity,and plasticity.We show that introducing heterogeneity and plasticity to cells can result in oscillation dynamics,as we have seen in the homogeneous stem cell regeneration system.However,increasing the cell heterogeneity and plasticity intends to maintain tissue homeostasis under certain conditions.The current study is an initiatory investigation of how cell heterogeneity and plasticity may affect stem cell regeneration dynamics,and many questions remain to be further studied both biologically and mathematically.

关键词： Stem cell regeneration Heterogenous Hopf bifurcation Hematopoietic dynamical disease

Three-dimensional choroidal vascularity index and choroidal thickness in fellow eyes of acute and chronic primary angle-closure using swept-source optical coherence tomography

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International Journal of Ophthalmology(English edition) 2024年第1期17卷 42-52页

作者： Hai-Li Huang Guan-Hong Wang liang-liang Niu Xing-Huai Sun Department of Ophthalmology&Visual Science Eye&ENT HospitalShanghai Medical CollegeFudan UniversityShanghai 200031China State Key Laboratory of Medical Neurobiology and MOE Frontiers Center for Brain Science Institutes of Brain ScienceFudan UniversityShanghai 200032China NHC Key Laboratory of Myopia Chinese Academy of Medical Sciencesand Shanghai Key Laboratory of Visual Impairment and Restoration(Fudan University)Shanghai 200031China

AIM:To compare the three-dimensional choroidal vascularity index(CVI)and choroidal thickness between fellow eyes of acute primary angle-closure(F-APAC)and chronic primary angle-closure glaucoma(F-CPACG)and the eyes of normal controls.METHODS:This study included 37 patients with unilateral APAC,37 with asymmetric CPACG without prior treatment,and 36 healthy participants.Using swept-source optical coherence tomography(SS-OCT),the macular and peripapillary choroidal thickness and three-dimensional CVI were measured and compared globally and sectorally.Pearson’s correlation analysis and multivariate regression models were used to evaluate choroidal thickness or CVI with related factors.RESULTS:The mean subfoveal CVIs were 0.35±0.10,0.33±0.09,and 0.29±0.04,and the mean subfoveal choroidal thickness were 315.62±52.92,306.22±59.29,and 262.69±45.55μm in the F-APAC,F-CPACG,and normal groups,respectively.All macular sectors showed significantly higher CVIs and choroidal thickness in the F-APAC and F-CPACG eyes than in the normal eyes(P<0.05),while there were no significant differences between the F-APAC and F-CPACG eyes.In the peripapillary region,the mean overall CVIs were 0.21±0.08,0.20±0.08,and 0.19±0.05,and the mean overall choroidal thickness were 180.45±54.18,174.82±50.67,and 176.18±37.94μm in the F-APAC,F-CPACG,and normal groups,respectively.There were no significant differences between any of the two groups in all peripapillary sectors.Younger age,shorter axial length,and the F-APAC or F-CPACG diagnosis were significantly associated with higher subfoveal CVI and thicker subfoveal choroidal thickness(P<0.05).CONCLUSION:The fellow eyes of unilateral APAC or asymmetric CPACG have higher macular CVI and choroidal thickness than those of the normal controls.Neither CVI nor choroidal thickness can distinguish between eyes predisposed to APAC or CPACG.A thicker choroid with a higher vascular volume may play a role in the pathogenesis of primary angle-closure glaucoma.

关键词： choroidal thickness choroidal vascularity index swept-source optical coherence tomography acute primary angle-closure chronic primary angle-closure glaucoma

Circularly polarized light emission and detection by chiral inorganic semiconductors

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Frontiers of Optoelectronics 2024年第2期17卷 43-49页

作者： Zha Li Wancai Li Dehui Li Wei Tang Huageng liang Huaibing Song Chao Chen liang Gao Jiang Tang Wuhan National Laboratory for Optoelectronics Huazhong University of Science and TechnologyWuhan 430074China School of Optical and Electronic Information Huazhong University of Science and TechnologyWuhan 430074China International Health Care Center National Center for Global Health and MedicineTokyo 162‑8655Japan Hepato‑Biliary‑Pancreatic Surgery Division Department of SurgeryThe University of Tokyo HospitalTokyo 113‑8655Japan Department of Urology Union HospitalTongji Medical CollegeHuazhong University of Science and TechnologyWuhan 430074China Faculty of Materials Science and Chemistry China University of GeosciencesWuhan 430074China

Chiral inorganic semiconductors with high dissymmetric factor are highly desirable,but it is generally difficult to induce chiral structure in inorganic semiconductors because of their structure rigidity and symmetry.In this study,we introduced chiral ZnO film as hard template to transfer chirality to CsPbBr3 film and PbS quantum dots(QDs)for circularly polarized light(CPL)emission and detection,respectively.The prepared CsPbBr_(3)/ZnO thin film exhibited CPL emission at 520 nm and the PbS QDs/ZnO film realized CPL detection at 780 nm,featuring high dissymmetric factor up to around 0.4.The electron transition based mechanism is responsible for chirality transfer.

关键词： High dissymmetric factor Circularly polarized light emission Semiconductor Hard template,Chirality

Emodin suppresses alkali burn-induced corneal inflammation and neovascularization by the vascular endothelial growth factor receptor 2 signaling pathway

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Journal of Traditional Chinese Medicine 2024年第2期44卷 268-276页

作者： ZHENG Xueying GUO liang LAI Siyi LI Fengyue liang Mingli LIU Wanting MENG Chun LIU Guanghui Department of Bioengineering College of Biological Science and BiotechnologyFuzhou UniversityFuzhou 350104China Eye Institute of Integrated Chinese and Western Medicine Fujian University of Traditional Chinese MedicineFuzhou 350004China Department of Ophthalmology Affiliated People's Hospital(Fujian Provincial People's Hospital)Fujian University of Traditional Chinese MedicineFuzhou 350004China

OBJECTIVE:To investigate the effects of emodin on alkali burn-induced corneal inflammation and neovascularization.METHODS:The ability of emodin to target vascular endothelial growth factor receptor 2(VEGFR2)was predicted by molecular docking.The effects of emodin on the invasion,migration,and proliferation of human umbilical vein endothelial cells(HUVEC)were determined by cell counting kit-8,Transwell,and tube formation assays.Analysis of apoptosis was performed by flow cytometry.CD31 levels were examined by immunofluorescence.The abundance and phosphorylation state of VEGFR2,protein kinase B(Akt),signal transducer and activator of transcription 3(STAT3),and P38 were examined by immunoblot analysis.Corneal alkali burn was performed on 40 mice.Animals were divided randomly into two groups,and the alkali-burned eyes were then treated with drops of either 10μM emodin or phosphate buffered saline(PBS)four times a day.Slitlamp microscopy was used to evaluate inflammation and corneal neovascularization(CNV)in all eyes on Days 0,7,10,and 14.The mice were killed humanely 14 d after the alkali burn,and their corneas were removed and preserved at-80℃ until histological study or protein extraction.RESULTS:Molecular docking confirmed that emodin was able to target VEGFR2.The findings revealed that emodin decreased the invasion,migration,angiogenesis,and proliferation of HUVEC in a dose-dependent manner.In mice,emodin suppressed corneal inflammatory cell infiltration and inhibited the development of corneal neovascularization induced by alkali burn.Compared to those of the PBS-treated group,lower VEGFR2 expression and CD31 levels were found in the emodintreated group.Emodin dramatically decreased the expression of VEGFR2,p-VEGFR2,p-Akt,p-STAT3,and p-P38 in VEGF-treated HUVEC.CONCLUSION:This study provides a new avenue for evaluating the molecular mechanisms underlying corneal inflammation and neovascularization.Emodin might be a promising new therapeutic option for corneal alkali burns.

关键词： alkali burn emodin corneal inflammation corneal neovascularisation vascular endothelial growth factor receptor-2 signal transduction