Purpose:Shaping and assembling contemporary external fixators rapidly for the severe mandibular fractures remains a challenge,especially in emergency circumstance.We designed a novel external fixator that incorporates...Purpose:Shaping and assembling contemporary external fixators rapidly for the severe mandibular fractures remains a challenge,especially in emergency circumstance.We designed a novel external fixator that incorporates universal joints to provide the stabilization for mandibular comminuted fractures.This study aims to confirm the efficacy of this novel external fixator through biomechanical tests in vitro and animal experiments.Methods:In vitro biomechanical tests were conducted using 6 fresh canine with mandibular defect to simulate critical comminuted fractures.Three mandibles were stabilized by the novel external fixator and other mandibles were fixed by 2.5 mm reconstruction plates.All fixed mandibles were subjected to loads of 350 N on the anterior regions of teeth and 550 N on the first molar of the unaffected side.The stability was evaluated based on the maximum displacement and the slope of the load-displacement curve.In animal experiments,9 beagles with comminuted mandibular fractures were divided into 3 groups,which were treated with the novel external fixation,reconstruction plate,and dental arch bar,respectively.The general observation,the changes in animals’weight,and the surgical duration were recorded and compared among 3 groups.The CT scans were performed at various intervals of 0 day(immediately after the surgery),3 days,7 days,14 days,21 days,and 28 days to analyze the displacement of feature points on the canine mandible and situation of fracture healing at 28 days.The statistical significance was assessed by the two-way analysis of variance test followed by the Bonferroni test,enabling multiple comparisons for all tests using GraphPad Prism10.1.0(GraphPad Inc,USA).Results:The outcomes of the biomechanical tests indicated that no statistically significant differences were found in terms of the maximum displacement(p=0.496,0.079)and the slope of load displacement curves(p=0.374,0.349)under 2 load modes between the external and internal fixation groups.The animal experiment data showed that there were minor displacements of feature points between the external and internal fixation groups without statistic difference,while the arch bar group demonstrated inferior stability.The CT analysis revealed that the best fracture healing happened in the internal fixation group,followed by the external fixation and arch baring at 28 days after fixation.The external fixation group had the shortest fixation duration(25.67±3.79)min compared to internal fixation((70.67±4.51)min,p<0.001)and arch baring((42.00±3.00)min,p=0.046).Conclusion:The conclusion of this study highlighted the efficacy and reliability of this novel external fixator in managing mandibular fractures rapidly,offering a viable option for the initial stabilization of comminuted mandibular fractures in the setting of emergency rescue.展开更多
指挥控制、作战管理和通信（command and control，battle management and communications，c2BMC）系统是美国弹道导弹防御的核心。通过详细分析C2BMC系统的功能、目标和研制进展，找出了其薄弱环节，在此基础上提出了一些对策与思考...指挥控制、作战管理和通信（command and control，battle management and communications，c2BMC）系统是美国弹道导弹防御的核心。通过详细分析C2BMC系统的功能、目标和研制进展，找出了其薄弱环节，在此基础上提出了一些对策与思考，对弹道导弹的发展建设具有重要指导意义。展开更多
一体化防空反导作战指控系统(integrated air and missile defense battle command system,IBCS),既是支撑美防空炮兵力量转型建设与作战概念创新发展的核心系统,更是深度集成与一体运用多域多型防空反导作战要素的重要平台,其基线型于2...一体化防空反导作战指控系统(integrated air and missile defense battle command system,IBCS),既是支撑美防空炮兵力量转型建设与作战概念创新发展的核心系统,更是深度集成与一体运用多域多型防空反导作战要素的重要平台,其基线型于2022年开始列装部队。在前期总体研究的基础上,对IBCS的系统组成、设备功能、关联关系、部队配置等进行了拓展分析。指出其作战中心“一型装备、多层指挥递阶适配,一套软件、多种角色功能配置”的新质部署能力,并基于作战中心类型配置分析,讨论了IBCS的作战运用模式与特点。结合IBCS系统组成研究,提出了相应启示与建议。展开更多
基金supported by Research projects of State Key Laboratory of Oral&Maxillofacial Reconstruction and Regeneration[grant number:2020ZB03 and LX2021-101]Key research and development program of Shaanxi Province[2024SF-YBXM-264].
文摘Purpose:Shaping and assembling contemporary external fixators rapidly for the severe mandibular fractures remains a challenge,especially in emergency circumstance.We designed a novel external fixator that incorporates universal joints to provide the stabilization for mandibular comminuted fractures.This study aims to confirm the efficacy of this novel external fixator through biomechanical tests in vitro and animal experiments.Methods:In vitro biomechanical tests were conducted using 6 fresh canine with mandibular defect to simulate critical comminuted fractures.Three mandibles were stabilized by the novel external fixator and other mandibles were fixed by 2.5 mm reconstruction plates.All fixed mandibles were subjected to loads of 350 N on the anterior regions of teeth and 550 N on the first molar of the unaffected side.The stability was evaluated based on the maximum displacement and the slope of the load-displacement curve.In animal experiments,9 beagles with comminuted mandibular fractures were divided into 3 groups,which were treated with the novel external fixation,reconstruction plate,and dental arch bar,respectively.The general observation,the changes in animals’weight,and the surgical duration were recorded and compared among 3 groups.The CT scans were performed at various intervals of 0 day(immediately after the surgery),3 days,7 days,14 days,21 days,and 28 days to analyze the displacement of feature points on the canine mandible and situation of fracture healing at 28 days.The statistical significance was assessed by the two-way analysis of variance test followed by the Bonferroni test,enabling multiple comparisons for all tests using GraphPad Prism10.1.0(GraphPad Inc,USA).Results:The outcomes of the biomechanical tests indicated that no statistically significant differences were found in terms of the maximum displacement(p=0.496,0.079)and the slope of load displacement curves(p=0.374,0.349)under 2 load modes between the external and internal fixation groups.The animal experiment data showed that there were minor displacements of feature points between the external and internal fixation groups without statistic difference,while the arch bar group demonstrated inferior stability.The CT analysis revealed that the best fracture healing happened in the internal fixation group,followed by the external fixation and arch baring at 28 days after fixation.The external fixation group had the shortest fixation duration(25.67±3.79)min compared to internal fixation((70.67±4.51)min,p<0.001)and arch baring((42.00±3.00)min,p=0.046).Conclusion:The conclusion of this study highlighted the efficacy and reliability of this novel external fixator in managing mandibular fractures rapidly,offering a viable option for the initial stabilization of comminuted mandibular fractures in the setting of emergency rescue.
文摘指挥控制、作战管理和通信（command and control，battle management and communications，c2BMC）系统是美国弹道导弹防御的核心。通过详细分析C2BMC系统的功能、目标和研制进展，找出了其薄弱环节，在此基础上提出了一些对策与思考，对弹道导弹的发展建设具有重要指导意义。
文摘一体化防空反导作战指控系统(integrated air and missile defense battle command system,IBCS),既是支撑美防空炮兵力量转型建设与作战概念创新发展的核心系统,更是深度集成与一体运用多域多型防空反导作战要素的重要平台,其基线型于2022年开始列装部队。在前期总体研究的基础上,对IBCS的系统组成、设备功能、关联关系、部队配置等进行了拓展分析。指出其作战中心“一型装备、多层指挥递阶适配,一套软件、多种角色功能配置”的新质部署能力,并基于作战中心类型配置分析,讨论了IBCS的作战运用模式与特点。结合IBCS系统组成研究,提出了相应启示与建议。
