AIM:Regulatory T cells(Tregs)are a specialized subset of CD4^(+)T cells primarily involved in im⁃munosuppressive functions.AMP-activated protein kinase(AMPK)serves as a metabolic sensor that governs the differen⁃tiati...AIM:Regulatory T cells(Tregs)are a specialized subset of CD4^(+)T cells primarily involved in im⁃munosuppressive functions.AMP-activated protein kinase(AMPK)serves as a metabolic sensor that governs the differen⁃tiation,maturation,and immune functions of Tregs through metabolic reprogramming.However,the impact of AMPKα1(the catalytic subunit of AMPK)knockout specifically in Tregs on the host's immune microenvironment remains largely un⁃explored.METHODS:Histological changes in immune organs were assessed using HE staining.The types of immune cells and their relative population percentages in immune organs and blood were quantified through flow cytometry in both AMPKα1flox/flox(AMPKα1^(fl/fl))mice and Treg-specific AMPKα1 knockout mice(AMPKα1^(fl/fl)Foxp3^(cre)mice).RESULTS:Compared to AMPKα1^(fl/fl)mice,the percentage of eosinophils in the bone marrow of AMPKα1^(fl/fl)Foxp3^(cre)mice was significant⁃ly reduced.Additionally,while the thymus of AMPKα1^(fl/fl)Foxp3^(cre)mice exhibited normal structure,both its size and the ratio of thymus weight to body weight were significantly decreased.The knockout of AMPKα1 in Tregs led to a notable reduction in the total percentage of immature double-negative(DN)cells.Consequently,the percentage of CD4^(+)T cells derived from these DN cells also decreased,even though the percentages of DN1 and DN4 cells were higher in the thymus of AMPKα1^(fl/fl)Foxp3^(cre)mice compared to AMPKα1^(fl/fl)mice.Importantly,the proportion of Siglec-F+CD11b^(+)eosinophils in the thymus was significantly lower in AMPKα1^(fl/fl)Foxp3^(cre)mice.Knockout of AMPKα1 in Tregs resulted in a marked increase in the percentage of CD4^(+)T cells in peripheral blood,alongside a decrease in the proportion of mature CD8^(+)T cells.Similarly,the proportion of CD4^(+)T cells in the spleen of AMPKα1^(fl/fl)Foxp3^(cre)mice was elevated compared to AMPKα1^(fl/fl)mice.In contrast,the proportion of neutrophils significantly decreased,while mononuclear cell proportions increased in the spleen of AMPKα1^(fl/fl)Foxp3^(cre)mice.In lymph nodes,the medullary boundaries in AMPKα1^(fl/fl)Foxp3^(cre)mice were blurred,and the lymphoid follicles were missing,a feature not observed in AMPKα1^(fl/fl)mice.Furthermore,the knockout of AMPKα1 in Tregs reduced the CD3^(+)T cell population,particularly the CD8^(+)T cell population,in lymph nodes.Although the mature Treg cell population was significantly lower in AMPKα1^(fl/fl)Foxp3^(cre)mice,the percentage of CD4^(+)T cells was markedly in⁃creased.In contrast,there was no statistically significant difference in granulocyte populations between AMPKα1^(fl/fl)Foxp3^(cre)and AMPKα1^(fl/fl)mice.CONCLUSION:The populations of mature Tregs,CD8^(+)T cells and eosinophils in various im⁃mune organs were significantly altered in mice with Treg-specific AMPKα1 knockout,suggesting a potential remodeling of the host immune microenvironment in response to inflammatory stimuli.展开更多
Effect of electromagnetic stirring on microstructure of AZ91-0.8%Ce magnesium alloy was investigated. The results show that electromagnetic stirring causes a change of morphology of α-Mg phase from coarse dendrites t...Effect of electromagnetic stirring on microstructure of AZ91-0.8%Ce magnesium alloy was investigated. The results show that electromagnetic stirring causes a change of morphology of α-Mg phase from coarse dendrites to fine rosette-like or spherical shape. Grain size is significantly refined within the range of input voltage 75?125 V, moreover, the optimum input voltage corresponded to the minimum value (64 μm) of grain size is 125 V. Compared to the non-stirred condition, the amount of β-Mg17Al12 precipitate under the stirred condition obviously increases. The grain refinement of AZ91-0.8%Ce alloy is mainly attributed to multiplication of existing grains in the melt caused by forced fluid flow under electromagnetic stirring condition. Addition of 0.8% Ce results in the formation of ‘necking’ at secondary dendrite arm roots of α-Mg crystals, and consequently, it is helpful to increase the number of heterogeneous nucleation.展开更多
In the present work, scandium elements with a series of contents(0.06 wt.%, 0.10 wt.%, 0.14 wt.%,0.17 wt.%, 0.20 wt.% and 0.25 wt.%) were added in a high Zn-containing Al-Zn-Mg-Cu-Zr alloy and the corresponding as-cas...In the present work, scandium elements with a series of contents(0.06 wt.%, 0.10 wt.%, 0.14 wt.%,0.17 wt.%, 0.20 wt.% and 0.25 wt.%) were added in a high Zn-containing Al-Zn-Mg-Cu-Zr alloy and the corresponding as-cast microstructure characteristics including grains and phases were thoroughly investigated. The results indicated that fine grain boundaries existed in these alloys and fine MgZn2phases discontinuously distributed on them. Besides,AlZnMgCu eutectic phases and Sc, Zr-containing phases with flocculent morphology were observed. As scandium contents vary from 0.06 wt.% to 0.17 wt.%, the average grain size continuously decreased and its equiaxial characteristics were strengthened. Meanwhile, the content of AlZnMgCu eutectic phase showed a decrease trend. When scandium contents were 0.20 wt.% and 0.25 wt.%, no further enhancement on grain refinement was observed, so as to the reduction of AlZnMgCu eutectic phase content. Besides, Sc, Zr-containing phases with blocky morphology were observed and the alloy with a scandium content of 0.25 wt.% possessed a larger amount of blocky Sc, Zr-containing phase than the alloy with a scandium content of 0.20 wt.%. Grain refinement and reduction of AlZnMgCu eutectic phase content associated with scandium addition were discussed.展开更多
In current research,the interactive effects of different parameters such as melt overheating temperature,the location of gating system and incorporation of the grain refiner in bar and micro-powder form on the mechani...In current research,the interactive effects of different parameters such as melt overheating temperature,the location of gating system and incorporation of the grain refiner in bar and micro-powder form on the mechanical and structural characteristics of commercially pure aluminium are examined.Results show that increasing the melt temperature as well as employing a gating system with higher heat transfer rate increases the ultimate tensile strength(UTS)of the pure aluminium by 7%.Also,the introduction of 2wt%Al–5Ti–1B grain refiner in bar form into the overheated melt enhances the UTS values by two times,while incorporating 2wt%Al–5Ti–1B grain refiner in micro-powder form leads to achieving 32%higher UTS compared to the samples with grain refiner in the bar form due to the elimination of Al3Ti brittle phase,as confirmed by XRD patterns and SEM fracture surface images.展开更多
基金Supported by the National Natural Science Foundation of China(No.81800423)the Guangdong Medical Science and Technology Research project(No.B2022102)。
文摘AIM:Regulatory T cells(Tregs)are a specialized subset of CD4^(+)T cells primarily involved in im⁃munosuppressive functions.AMP-activated protein kinase(AMPK)serves as a metabolic sensor that governs the differen⁃tiation,maturation,and immune functions of Tregs through metabolic reprogramming.However,the impact of AMPKα1(the catalytic subunit of AMPK)knockout specifically in Tregs on the host's immune microenvironment remains largely un⁃explored.METHODS:Histological changes in immune organs were assessed using HE staining.The types of immune cells and their relative population percentages in immune organs and blood were quantified through flow cytometry in both AMPKα1flox/flox(AMPKα1^(fl/fl))mice and Treg-specific AMPKα1 knockout mice(AMPKα1^(fl/fl)Foxp3^(cre)mice).RESULTS:Compared to AMPKα1^(fl/fl)mice,the percentage of eosinophils in the bone marrow of AMPKα1^(fl/fl)Foxp3^(cre)mice was significant⁃ly reduced.Additionally,while the thymus of AMPKα1^(fl/fl)Foxp3^(cre)mice exhibited normal structure,both its size and the ratio of thymus weight to body weight were significantly decreased.The knockout of AMPKα1 in Tregs led to a notable reduction in the total percentage of immature double-negative(DN)cells.Consequently,the percentage of CD4^(+)T cells derived from these DN cells also decreased,even though the percentages of DN1 and DN4 cells were higher in the thymus of AMPKα1^(fl/fl)Foxp3^(cre)mice compared to AMPKα1^(fl/fl)mice.Importantly,the proportion of Siglec-F+CD11b^(+)eosinophils in the thymus was significantly lower in AMPKα1^(fl/fl)Foxp3^(cre)mice.Knockout of AMPKα1 in Tregs resulted in a marked increase in the percentage of CD4^(+)T cells in peripheral blood,alongside a decrease in the proportion of mature CD8^(+)T cells.Similarly,the proportion of CD4^(+)T cells in the spleen of AMPKα1^(fl/fl)Foxp3^(cre)mice was elevated compared to AMPKα1^(fl/fl)mice.In contrast,the proportion of neutrophils significantly decreased,while mononuclear cell proportions increased in the spleen of AMPKα1^(fl/fl)Foxp3^(cre)mice.In lymph nodes,the medullary boundaries in AMPKα1^(fl/fl)Foxp3^(cre)mice were blurred,and the lymphoid follicles were missing,a feature not observed in AMPKα1^(fl/fl)mice.Furthermore,the knockout of AMPKα1 in Tregs reduced the CD3^(+)T cell population,particularly the CD8^(+)T cell population,in lymph nodes.Although the mature Treg cell population was significantly lower in AMPKα1^(fl/fl)Foxp3^(cre)mice,the percentage of CD4^(+)T cells was markedly in⁃creased.In contrast,there was no statistically significant difference in granulocyte populations between AMPKα1^(fl/fl)Foxp3^(cre)and AMPKα1^(fl/fl)mice.CONCLUSION:The populations of mature Tregs,CD8^(+)T cells and eosinophils in various im⁃mune organs were significantly altered in mice with Treg-specific AMPKα1 knockout,suggesting a potential remodeling of the host immune microenvironment in response to inflammatory stimuli.
基金Project(2004ABA110) supported by the Natural Science Foundation of Hubei Province project(471-38300843) supported by the Research Foundation for the Doctoral Program of Wuhan University of Technology
文摘Effect of electromagnetic stirring on microstructure of AZ91-0.8%Ce magnesium alloy was investigated. The results show that electromagnetic stirring causes a change of morphology of α-Mg phase from coarse dendrites to fine rosette-like or spherical shape. Grain size is significantly refined within the range of input voltage 75?125 V, moreover, the optimum input voltage corresponded to the minimum value (64 μm) of grain size is 125 V. Compared to the non-stirred condition, the amount of β-Mg17Al12 precipitate under the stirred condition obviously increases. The grain refinement of AZ91-0.8%Ce alloy is mainly attributed to multiplication of existing grains in the melt caused by forced fluid flow under electromagnetic stirring condition. Addition of 0.8% Ce results in the formation of ‘necking’ at secondary dendrite arm roots of α-Mg crystals, and consequently, it is helpful to increase the number of heterogeneous nucleation.
基金Projects(2020YFB0311400ZL, 2020YFF0218202) supported by the National Key R&D Program of ChinaProject supported by Youth Fund Project of GRINM Group Co.,Ltd.,China。
文摘In the present work, scandium elements with a series of contents(0.06 wt.%, 0.10 wt.%, 0.14 wt.%,0.17 wt.%, 0.20 wt.% and 0.25 wt.%) were added in a high Zn-containing Al-Zn-Mg-Cu-Zr alloy and the corresponding as-cast microstructure characteristics including grains and phases were thoroughly investigated. The results indicated that fine grain boundaries existed in these alloys and fine MgZn2phases discontinuously distributed on them. Besides,AlZnMgCu eutectic phases and Sc, Zr-containing phases with flocculent morphology were observed. As scandium contents vary from 0.06 wt.% to 0.17 wt.%, the average grain size continuously decreased and its equiaxial characteristics were strengthened. Meanwhile, the content of AlZnMgCu eutectic phase showed a decrease trend. When scandium contents were 0.20 wt.% and 0.25 wt.%, no further enhancement on grain refinement was observed, so as to the reduction of AlZnMgCu eutectic phase content. Besides, Sc, Zr-containing phases with blocky morphology were observed and the alloy with a scandium content of 0.25 wt.% possessed a larger amount of blocky Sc, Zr-containing phase than the alloy with a scandium content of 0.20 wt.%. Grain refinement and reduction of AlZnMgCu eutectic phase content associated with scandium addition were discussed.
文摘In current research,the interactive effects of different parameters such as melt overheating temperature,the location of gating system and incorporation of the grain refiner in bar and micro-powder form on the mechanical and structural characteristics of commercially pure aluminium are examined.Results show that increasing the melt temperature as well as employing a gating system with higher heat transfer rate increases the ultimate tensile strength(UTS)of the pure aluminium by 7%.Also,the introduction of 2wt%Al–5Ti–1B grain refiner in bar form into the overheated melt enhances the UTS values by two times,while incorporating 2wt%Al–5Ti–1B grain refiner in micro-powder form leads to achieving 32%higher UTS compared to the samples with grain refiner in the bar form due to the elimination of Al3Ti brittle phase,as confirmed by XRD patterns and SEM fracture surface images.
