目的分析载脂蛋白E(apoE)ε4等位基因分型的健康老年人静息态全脑功能连接强度(FCS)特征,探讨apoEε4基因型调控认知正常老年人的脑功能网络拓扑组织结构的机制。方法入选的44例健康老年人的人口统计学资料、MRI数据、apoEε4信息均来...目的分析载脂蛋白E(apoE)ε4等位基因分型的健康老年人静息态全脑功能连接强度(FCS)特征,探讨apoEε4基因型调控认知正常老年人的脑功能网络拓扑组织结构的机制。方法入选的44例健康老年人的人口统计学资料、MRI数据、apoEε4信息均来自美国公开数据库。根据是否携带apoEε4将入选者分为apoEε4组14例和非apoEε4组30例。进行静息态功能MRI(rs-fMRI)扫描和神经心理学评估,采集rs-fMRI数据进行预处理,计算全脑长程和短程FCS值,比较2组差异。结果静息状态下,与非apoeEε4组比较,apoEε4组右侧岛叶长程FCS值减低(簇大小为183个体素,14656.88±3762.93 vs 20905.82±10245.85,P<0.05),左侧岛叶、右侧岛叶及右侧海马/梭状回短程FCS值减低(簇大小分别为91、232和75个体素,P<0.05)。结论携带apoEε4的健康老年人可不表现认知功能的损害,但其FCS值与非携带者存在差异,这可能是apoEε4基因潜在的神经生物学效应。展开更多
The as-cast pure magnesium(Mg), with a purity of 99.99%, was hot-extruded at 300 ℃ to prepare a Mg bar with a diameter of 8 mm. The microstructure and mechanical properties of the sample before and after extrusion we...The as-cast pure magnesium(Mg), with a purity of 99.99%, was hot-extruded at 300 ℃ to prepare a Mg bar with a diameter of 8 mm. The microstructure and mechanical properties of the sample before and after extrusion were investigated. The results show that the as-extruded microstructure is obviously refined with a large number of subgrains rather than equiaxed grains. A great number of(102) tensile twins can be observed significantly in the microstructure at the temperature. Mechanical properties including yield strength(YS) and ultimate tensile strength(UTS) increase greatly but uniform elongation(UE) decreases slightly as a result of work hardening.展开更多
文摘目的分析载脂蛋白E(apoE)ε4等位基因分型的健康老年人静息态全脑功能连接强度(FCS)特征,探讨apoEε4基因型调控认知正常老年人的脑功能网络拓扑组织结构的机制。方法入选的44例健康老年人的人口统计学资料、MRI数据、apoEε4信息均来自美国公开数据库。根据是否携带apoEε4将入选者分为apoEε4组14例和非apoEε4组30例。进行静息态功能MRI(rs-fMRI)扫描和神经心理学评估,采集rs-fMRI数据进行预处理,计算全脑长程和短程FCS值,比较2组差异。结果静息状态下,与非apoeEε4组比较,apoEε4组右侧岛叶长程FCS值减低(簇大小为183个体素,14656.88±3762.93 vs 20905.82±10245.85,P<0.05),左侧岛叶、右侧岛叶及右侧海马/梭状回短程FCS值减低(簇大小分别为91、232和75个体素,P<0.05)。结论携带apoEε4的健康老年人可不表现认知功能的损害,但其FCS值与非携带者存在差异,这可能是apoEε4基因潜在的神经生物学效应。
基金Funded by National Natural Science Foundation of China(Nos.51474152,51274149,51175363)
文摘The as-cast pure magnesium(Mg), with a purity of 99.99%, was hot-extruded at 300 ℃ to prepare a Mg bar with a diameter of 8 mm. The microstructure and mechanical properties of the sample before and after extrusion were investigated. The results show that the as-extruded microstructure is obviously refined with a large number of subgrains rather than equiaxed grains. A great number of(102) tensile twins can be observed significantly in the microstructure at the temperature. Mechanical properties including yield strength(YS) and ultimate tensile strength(UTS) increase greatly but uniform elongation(UE) decreases slightly as a result of work hardening.