In the present study, we illustrate the strategy and protocol required to generate rice transgenics over-expressing the 21-nt form of Osa-miR820. The miR exists in two size variants of 21-nt and 24-nt so the natural p...In the present study, we illustrate the strategy and protocol required to generate rice transgenics over-expressing the 21-nt form of Osa-miR820. The miR exists in two size variants of 21-nt and 24-nt so the natural precursor cannot be employed for the purpose of miR over-expression as the cellular machinery can process both size variants thereby masking the role of PTGS regulation. Hence, we adopted the artificial miR technology to specifically over-express the 21-nt species in the transgenics. During the course of experiments it was observed that the amiR constructs probably interfered with the regeneration of the transformed callus, necessitating protocol modifications. The results indicate the successful over-expression of the 21-nt miR species. These plants can serve as a useful source for the functional dissection of the role played by the 21-nt Osa-miR820 species. They will also be valuable in highlighting the importance for the existence of a dual mode of miR mediated target regulation.展开更多
利用扩孔实验机对合金成本优化前后1.2 mm CR820/1180DP扩孔性能进行了测定,并结合扩孔试验位移-载荷曲线、微观组织、力学性能拉伸曲线查找扩孔性能差异的原因。结果认为:优化后低合金成本CR820/1180DP微观组织状态大幅改善,表现为铁...利用扩孔实验机对合金成本优化前后1.2 mm CR820/1180DP扩孔性能进行了测定,并结合扩孔试验位移-载荷曲线、微观组织、力学性能拉伸曲线查找扩孔性能差异的原因。结果认为:优化后低合金成本CR820/1180DP微观组织状态大幅改善,表现为铁素体相形态由条带状变为球状或等轴状分布;马氏体则由条状聚集态变为团簇球状形态,且优化后马氏体相内发现大量(Fe,Mn)xCy粒状碳化物析出;扩孔性能较优化前提升1倍以上,平均极限扩孔率在25.2%,其主要是由于优化后CR820/1180DP铁-马双相弥散分布形态,相界面为球状,马氏体晶粒内部大量的第二相析出,大幅降低了扩孔实验过程中铁-马两相界面应力集中程度,且界面处发生应力集中也相对滞后,当应变发生在马氏体相时,由于其晶粒内部粒状第二相的存在,随塑性变形发生位错以绕过或切过第二相粒子的形式增强材料强度是扩孔性能大幅提升的根本原因。优化后低合金成本CR820/1180DP成功应用于前保险杠横梁的辊压成形制作,解决了CR820/1180DP辊压开裂的难题。展开更多
文摘In the present study, we illustrate the strategy and protocol required to generate rice transgenics over-expressing the 21-nt form of Osa-miR820. The miR exists in two size variants of 21-nt and 24-nt so the natural precursor cannot be employed for the purpose of miR over-expression as the cellular machinery can process both size variants thereby masking the role of PTGS regulation. Hence, we adopted the artificial miR technology to specifically over-express the 21-nt species in the transgenics. During the course of experiments it was observed that the amiR constructs probably interfered with the regeneration of the transformed callus, necessitating protocol modifications. The results indicate the successful over-expression of the 21-nt miR species. These plants can serve as a useful source for the functional dissection of the role played by the 21-nt Osa-miR820 species. They will also be valuable in highlighting the importance for the existence of a dual mode of miR mediated target regulation.
文摘利用扩孔实验机对合金成本优化前后1.2 mm CR820/1180DP扩孔性能进行了测定,并结合扩孔试验位移-载荷曲线、微观组织、力学性能拉伸曲线查找扩孔性能差异的原因。结果认为:优化后低合金成本CR820/1180DP微观组织状态大幅改善,表现为铁素体相形态由条带状变为球状或等轴状分布;马氏体则由条状聚集态变为团簇球状形态,且优化后马氏体相内发现大量(Fe,Mn)xCy粒状碳化物析出;扩孔性能较优化前提升1倍以上,平均极限扩孔率在25.2%,其主要是由于优化后CR820/1180DP铁-马双相弥散分布形态,相界面为球状,马氏体晶粒内部大量的第二相析出,大幅降低了扩孔实验过程中铁-马两相界面应力集中程度,且界面处发生应力集中也相对滞后,当应变发生在马氏体相时,由于其晶粒内部粒状第二相的存在,随塑性变形发生位错以绕过或切过第二相粒子的形式增强材料强度是扩孔性能大幅提升的根本原因。优化后低合金成本CR820/1180DP成功应用于前保险杠横梁的辊压成形制作,解决了CR820/1180DP辊压开裂的难题。
