Objective To study the antitumor activities of RRx-001 derivatives with novel covalent fragments. Methods Four targeted compounds were designed and synthesized. The structures were confirmed by ¹H NMR and HRMS. A549 and HCT116 cancer cell lines were selected for antiproliferative activity assays. Results All the compounds revealed antitumor activities and compound ZM528 showed the best antitumor activity against these two cell lines with IC₅₀ values of （5.1±4.8） μmol/L and （6.0±2.7） μmol/L, respectively. Conclusion The result indicated that bromoacetyl group of RRx-001 could be substituted with other covalent fragments.

Objective With the increasing demand from the country for optimizing the allocation of medical resources and improving service balance,this study aims to promote the improvement of regional medical service levels through the explora-tion and practice of the management model of provincial medical quality control centers.Methods The First Affiliated Hospital of Sun Yat-sen University,as the affiliated unit of one of the 14 provincial quality control centers,organizes the quality control center to play a professional role and improve its management efficiency through stable construction,solid framework,reorgani-zation,and multiple support.Results With the leadership and support of the health administrative department in Guangdong Province,the hospital has organized the provincial quality control center to carry out its work in an orderly manner,promoting the continuous improvement of the comprehensive strength of regional medical services and key indicators of various professional qual-ity control centers.Conclusion The management model of the quality control center in this study has shown initial effectiveness.

Objective With the increasing demand from the country for optimizing the allocation of medical resources and improving service balance,this study aims to promote the improvement of regional medical service levels through the explora-tion and practice of the management model of provincial medical quality control centers.Methods The First Affiliated Hospital of Sun Yat-sen University,as the affiliated unit of one of the 14 provincial quality control centers,organizes the quality control center to play a professional role and improve its management efficiency through stable construction,solid framework,reorgani-zation,and multiple support.Results With the leadership and support of the health administrative department in Guangdong Province,the hospital has organized the provincial quality control center to carry out its work in an orderly manner,promoting the continuous improvement of the comprehensive strength of regional medical services and key indicators of various professional qual-ity control centers.Conclusion The management model of the quality control center in this study has shown initial effectiveness.

In the paper, the optimal self-scaling strategy to the modified symmetric rank one (HSR1) update, which satisfies the modified quasi-Newton equation, is derived to improve the condition number of the updates. The scaling factors are derived from minimizing the estimate of upper bounds on the condition number of the updating matrix. Theoretical analysis, and numerical experiments and comparisons show that introducing the optimal scaling factor into the modified symmetric rank one update preserves the positive definiteness of updates, and greatly improves the stability and numerical performance of the modified symmetric rank one algorithm.