Prp19干涉导致细胞染色体错误排列及有丝分裂前中期阻滞

目的:验证针对实验室前期筛选到的新有丝分裂期调控分子候选蛋白mRNA前体剪切因子19(pre-mRNA processing factor 19,Prp19)功能和查明作用机制。方法:采用多个靶向不同序列的siRNA在He La细胞中敲低Prp19,应用流式细胞术检测Prp19敲减对细胞周期进程的影响。采用Time-lapse成像技术进一步明确Prp19干涉对细胞分裂的影响。采用冷处理实验观测Prp19干涉对微管与着丝粒连接的影响。应用AnnexinⅤ-FITC细胞凋亡检测和Caspase 3、PARP免疫印迹实验检测Prp19干涉对细胞凋亡的影响。结果:流式细胞术检测结果表明,Prp19干涉导致有丝分裂期阻滞。Time-lapse成像动态观测发现Prp19干涉导致细胞前中期阻滞和染色体错误排列。冷处理实验结果表明干涉Prp19损害了微管与着丝粒的连接。AnnexinⅤ-FITC细胞凋亡检测以及Caspase 3、PARP免疫印迹检测结果显示Prp19干涉导致肿瘤细胞凋亡。结论:Prp19是细胞有丝分裂正常进程中不可或缺少的蛋白质,抑制Prp19可能对抗有丝分裂的抗肿瘤药物研发提供新的策略。

降低GDX2包装机5号轮烟支排列错乱的研究

GD X2机组生产的烟包经常出现烟包内烟支排列错误的现象。而且机器的运转速度越快,这种现象越频繁,影响产品质量越严重。经检查,烟组是在5号轮模盒内发生错乱。原因是模盒内腔尺寸远大于烟组外形尺寸。模盒内腔尺寸改小的可行性是消除烟组内烟支错乱的关键。经过对模盒内部结构及其与相邻部件关系的分析,决定通过增加模盒内腔底部厚度,改小模盒内腔尺寸,达到烟支在模盒内无窜动的目的。改进后,5号轮模盒内烟组排列错乱现象彻底消除,保证了产品质量。

A review of the end-effector of large space manipulator with capabilities of misalignment tolerance and soft capture

The space manipulator which has advantages of high dexterity and universality, is used to the space capturing usually. According to the different types of mechanical interfaces of targets, the on orbit capturing operation includes capturing of cooperative target and capturing of uncooperative target. The performances of the famous large space manipulators named space shuttle remote manipulator system(SRMS), the space station remote manipulator system(SSRMS) and the Europe robotic arm(ERA) are reviewed and studied respectively. Moreover, the space manipulators being developed by China for space station is also surveyed. Based on the performance analysis of the large space manipulators and end-effectors, which are adapted to the construction and daily maintenance for the large space structure such as the space station, the basic requirements of large misalignment tolerance capability, soft capturing capability and hard docking capability for the end-effector of large space manipulator are proposed in this paper. According to these requirements, the capture mechanism and methods that can enable the end-effector to have the capability of misalignment tolerance and soft capturing are presented. The development trend and key technologies of the large space manipulators and the end-effectors are also reviewed.

Misalignment analysis of journal bearing influenced by asymmetric deflection,based on a simple stepped shaft model

The effects of journal misalignment on a journal bearing caused by an asymmetric rotor structure are presented in this study.A new model considering the asymmetric deflection is applied.Also,the thermo-hydrodynamic of the oil film in the journal bearing and straightforward elasticity theory are considered in the analysis.Based on the structure stiffness equivalent characteristic,a simple stepped shaft can reflect the entire complex structure model.The existing lubrication model,which does not consider this angle component,is not very precise for journal bearings.Film pressure,misalignment angle,velocity field,oil leakage,and temperature field were calculated and compared in the journal bearing analysis.The results indicate that bearing performances are greatly affected by misalignment caused by the asymmetric structure.A simple stepped shaft can effectively represent a misaligned journal bearing in a rotor-bearing system.

A new method for studying the 3D transient flow of misaligned journal bearings in flexible rotor-bearing systems

The effects of journal misalignment on the transient flow of a finite grooved journal bearing are presented in this study. A new 3D computational fluid dynamics (CFD) analysis method is applied. Also, the quasi-coupling calculation of transient fluid dynamics of oil film in journal bearing and rotor dynamics is considered in the analysis. Based on the structured mesh, a new approach for mesh movement is proposed to update the mesh volume when the journal moves during the fluid dynamics simula- tion of an oil film. Existing dynamic mesh models provided by FLUENT are not suitable for the transient oil flow in journal bearings. The movement of the journal is obtained by solving the moving equations of the rotor-bearing system with the calculated film pressure as the boundary condition of the load. The data exchange between fluid dynamics and rotor dynamics is realized by data files. Results obtained from the CFD model were consistent with previous experimental results on misaligned journal bearings. Film pressure, oil film force, friction torque, misalignment moment and attitude angle were calculated and compared for mis- aligned and aligned journal bearings. The results indicate that bearing performances are greatly affected by misalignment which is caused by unbalanced excitation, and the CFD method based on the fluid-structure interaction (FSI) technique can effectively predict the transient flow field of a misaligned journal bearing in a rotor-bearing system.

Periodic response analysis of a misaligned rotor system by harmonic balance method with alternating frequency/time domain technique

A dynamic model is established for an offset-disc rotor system with a mechanical gear coupling, which takes into consideration the nonlinear restoring force of rotor support and the effect of coupling misalignment. Periodic solutions are obtained through harmonic balance method with alternating frequency/time domain(HB-AFT) technique, and then compared with the results of numerical simulation. Good agreement confirms the feasibility of HB-AFT scheme. Moreover, the Floquet theory is adopted to analyze motion stability of the system when rotor runs at different speed intervals. A simple strategy to determine the monodromy matrix is introduced and two ways towards unstability are found for periodic solutions: the period doubling bifurcation and the secondary Hopf bifurcation. The results obtained will contribute to the global response analysis and dynamic optimal design of rotor systems.