Objective To improve the protective strategy of occupational risks for technicians in blood centers so as to ensure their health and safety.Methods The occupational risk factors were analyzed by the 5W1H method,and the corresponding protective measures were introduced.Then,the protective measures were verified dynamically by the PDCA circulation,and were standardized and further spread.The projects with poor effect were replanned and entered the PDCA recycling.Results The system of the 5W1H method combined with PDCA circulation could identify and control various occupational risks,and effectively prevent the occupational detriments.Condusion Combined application of the 5W1H method with PDCA circulation is an effective way to protect the health and safety of technicians in blood centers and an effective mode to improve the management of occupational risks.

Objective:To investigate the effect of IL-7 on differentiation of thymic T lymphocytes and dendritic cells' differentiation in vitro.Methods:Thymic lobes were apspectically removed from 15-day-old or 16-day-old mouse fetueses and were cultured by the way of fetal thymus organ cultures (FTOC) in vitro.Lobes were cultured in the dishes with or without Interleukin-7(IL-7),then collected the cultured cells respectively.The expression of CD4,CD8,CD11c,B220,Ia,and CD11b was detected by flow cytometry,and the morphology was observed under the ligt microscope.The proliferation of these cells was determined by cell counting.The cultured cells were used as stimulators for allogeneic T cells,whose proliferation were detected later by MTT method.Results:The result of cell counting indicated that the total amount of the thymocytes was decresed obviously after being cultured with IL-7,while the proportion of CD4~+ CD8~+ thymocytes decreased,the proportion of CD4~- CD8~-,and CD4~- CD8~+ thymocytes increased,and no much difference in the amount of CD4~+ CD8~- thymocytes was found.In addition,the amount of B lymphocytes,natural killer cells,and dendritic cells increased in different degree.Conclusion:IL-7 participates in differentiation and development of thymic T lymphocytes and dendritic cells.