目的:儿童白血病细胞全基因组芯片数据聚类分析发现,核糖体蛋白L4(ribosomal protein L4,RPL4)启动子区域具有转录因子Runx1的结合位点TTCATTCT,由此推测Runx1可能与该基因启动子之间存在调控作用。本研究通过观察Runx1蛋白与RPL4启动...目的:儿童白血病细胞全基因组芯片数据聚类分析发现,核糖体蛋白L4(ribosomal protein L4,RPL4)启动子区域具有转录因子Runx1的结合位点TTCATTCT,由此推测Runx1可能与该基因启动子之间存在调控作用。本研究通过观察Runx1蛋白与RPL4启动子之间的相互作用,了解Runx1对RPL4启动子转录活性的影响,探讨其在儿童白血病发生机制中的意义。方法:构建含RPL4启动子及其突变体的荧光素酶报告质粒,与Runx1的表达质粒共转染293T细胞,进行荧光素酶活性分析。结果:Runx1蛋白可使RPL4启动子的转录活性降低(P<0.01);随着Runx1剂量的增加,RPL4启动子的转录水平呈剂量依赖性降低(P<0.01);Runx1蛋白对RPL4启动子的突变体转录活性无调控作用(P>0.05)。结论:Runx1蛋白对RPL4启动子具有转录抑制作用,且具有明显的剂量依赖性;Runx1蛋白通过结合RPL4启动子区域的TTCATTCT位点发挥调控作用。展开更多
通过Pro/E软件建立某混凝土泵车臂架变幅机构的三维实体模型,将其导入ADAMS中,分析多种工况下的臂架仿真运动,找出最危险工况时油缸的最大受力,并利用ADAMS的DOE(Design Of Experiments)手段,很好地完成了臂架变幅机构的优化设计,明显...通过Pro/E软件建立某混凝土泵车臂架变幅机构的三维实体模型,将其导入ADAMS中,分析多种工况下的臂架仿真运动,找出最危险工况时油缸的最大受力,并利用ADAMS的DOE(Design Of Experiments)手段,很好地完成了臂架变幅机构的优化设计,明显地减小了油缸的最大受力,极大地提高了臂架系统的工作性能,为混凝土泵车臂架系统的动力学仿真提供了较为实用的分析方法。展开更多
Connecting a triangle base and an apex forms a simplest polyhedron-that is,a tetrahedron.On account of their structural simplicity and stability,two common classes of tetrahedra-namely,M4L4 and M4L6 (M indicates anion...Connecting a triangle base and an apex forms a simplest polyhedron-that is,a tetrahedron.On account of their structural simplicity and stability,two common classes of tetrahedra-namely,M4L4 and M4L6 (M indicates anions or metal cations,L indicates ligands with C3 symmetry for M4L4 and C2 symmetry for M4L6,respectively)-can be readily constructed from (i) six straight edges through an edge-bridged strategy or (ii) four triangle faces through a face-capped strategy,by means of supramolecular or coordination assembly.The intrinsic cavities inside tetrahedra enable them to act as versatile hosts for encapsulating a variety of guests,which leads to a wide range of applications including molecular recognition,catalysis,sensing and so on.In this review,we intend to summarize specifically the work carried out in the realm of porous tetrahedral cages.It includes representative synthetic strategies for the preparation of tetrahedra along with a general summary on their structural features.Thereafter,we will highlight the state-of-the-art progress in various functions of tetrahedra,in addition to presenting a full overview of applications wherein we aim to provide new insights into the design and preparation of new topological geometric structures and functional materials on the basis of the simplest polyhedron-tetrahedron.展开更多
文摘目的:儿童白血病细胞全基因组芯片数据聚类分析发现,核糖体蛋白L4(ribosomal protein L4,RPL4)启动子区域具有转录因子Runx1的结合位点TTCATTCT,由此推测Runx1可能与该基因启动子之间存在调控作用。本研究通过观察Runx1蛋白与RPL4启动子之间的相互作用,了解Runx1对RPL4启动子转录活性的影响,探讨其在儿童白血病发生机制中的意义。方法:构建含RPL4启动子及其突变体的荧光素酶报告质粒,与Runx1的表达质粒共转染293T细胞,进行荧光素酶活性分析。结果:Runx1蛋白可使RPL4启动子的转录活性降低(P<0.01);随着Runx1剂量的增加,RPL4启动子的转录水平呈剂量依赖性降低(P<0.01);Runx1蛋白对RPL4启动子的突变体转录活性无调控作用(P>0.05)。结论:Runx1蛋白对RPL4启动子具有转录抑制作用,且具有明显的剂量依赖性;Runx1蛋白通过结合RPL4启动子区域的TTCATTCT位点发挥调控作用。
文摘通过Pro/E软件建立某混凝土泵车臂架变幅机构的三维实体模型,将其导入ADAMS中,分析多种工况下的臂架仿真运动,找出最危险工况时油缸的最大受力,并利用ADAMS的DOE(Design Of Experiments)手段,很好地完成了臂架变幅机构的优化设计,明显地减小了油缸的最大受力,极大地提高了臂架系统的工作性能,为混凝土泵车臂架系统的动力学仿真提供了较为实用的分析方法。
文摘Connecting a triangle base and an apex forms a simplest polyhedron-that is,a tetrahedron.On account of their structural simplicity and stability,two common classes of tetrahedra-namely,M4L4 and M4L6 (M indicates anions or metal cations,L indicates ligands with C3 symmetry for M4L4 and C2 symmetry for M4L6,respectively)-can be readily constructed from (i) six straight edges through an edge-bridged strategy or (ii) four triangle faces through a face-capped strategy,by means of supramolecular or coordination assembly.The intrinsic cavities inside tetrahedra enable them to act as versatile hosts for encapsulating a variety of guests,which leads to a wide range of applications including molecular recognition,catalysis,sensing and so on.In this review,we intend to summarize specifically the work carried out in the realm of porous tetrahedral cages.It includes representative synthetic strategies for the preparation of tetrahedra along with a general summary on their structural features.Thereafter,we will highlight the state-of-the-art progress in various functions of tetrahedra,in addition to presenting a full overview of applications wherein we aim to provide new insights into the design and preparation of new topological geometric structures and functional materials on the basis of the simplest polyhedron-tetrahedron.
