密闭舱室内爆炸致大鼠失能性脑损伤的神经电生理机制研究

目的探讨密闭舱室内爆炸致大鼠失能性脑损伤的动态变化规律及神经电生理机制。方法 68只SD大鼠随机分为正常对照组(n=4)、开阔地爆炸组(OTB组,n=32)和舱室爆炸组(ECB组,n=32)。舱室爆炸组和开阔地爆炸组分别在模拟装甲舱室内和舱外以600mg雷管电起爆,动物距爆点21.5cm。观察大鼠伤前及伤后1、3、5、8、12、24、72h(每个时间点4只大鼠)失能性脑缺血面积和诱发电位的改变。结果舱室内、外爆炸后30min大鼠失能程度均为25%。TTC染色显示开OTB组伤后5h出现肉眼可见脑缺血区域,12h缺血区面积最大,至72h基本恢复正常;ECB组伤后3h即可见缺血区,至72h缺血区仍存在。诱发电位检测显示,ECB组伤后5h体感诱发电位N1波潜伏期延长,伤后8h运动诱发电位N1波潜伏期延长,且感觉变化先于运动变化。结论舱室爆炸致脑失能较开阔地爆炸更早且伤情更重,缺血区域和诱发电位的潜伏期可能与失能性脑损伤相关。

Linear and Nonlinear Ultrasonic Detections of Impact Damage in Composite Laminate

The appearance and accumulation of internal impact damage seriously influence overall performance of carbon fiber reinforced plastic(CFRP).Thus,this study evaluates the change in impact damage number by using linear and nonlinear ultrasonic Lamb wave detection methods,and compares these two detection results.An ultrasonic wave simulation model for composite structure with impact damage is established using the finite element method,and the interaction between impact damage and the ultrasonic wave is simulated.Simulation results demonstrate that the ultrasonic amplitude linearly decreases,and the relative nonlinear parameter linearly increases in proportion to the impact number,respectively.The linear-fitting slope of nonlinear parameter is 0.38 per impact number at an input frequency of 1.0 MHz.It is far higher than that of the linear ultrasonic amplitude,which is only-0.12.However,with the increase of impact damage,the linear growth of nonlinear parameters mainly depends on the decrease in ultrasonic amplitude rather than the accumulation of second harmonic amplitude.In the linear ultrasonic amplitude detection,the linear fitting slope at 1.1 MHz is-0.14,which is lower than those at 0.9 MHz and 1.0 MHz.Meanwhile,in the nonlinear ultrasonic parameter detection,the linear fitting slope at 1.1 MHz is 0.92,which is higher than those at 0.9 MHz and 1.0 MHz.The results show that higher frequencies lead to greater attenuation of ultrasonic amplitude and a larger increase in nonlinear parameters,which can enhance the sensitivity of both linear and nonlinear ultrasonic detections.The accuracy of simulation results is demonstrated through the low-velocity impact and ultrasonic experiments.The results show that compared with nonlinear ultrasonic technology,the linear ultrasonic technology is more suitable for impact damage assessment of carbon fiber reinforced plastic because of its simpler detection process and higher sensitivity.

舱内爆炸大鼠血液动力学的早期变化

背景:已证实冲击波和烟雾均可引起机体显著的血流动力学紊乱,但对冲击波烟雾复合伤时血流动力学特点少有文献报道。目的:探讨舱室内爆炸复合有害气体对大鼠血流动力学早期变化的影响,评价脑钠肽做为冲击波烟雾复合伤早期检测损伤指标的可行性。设计、时间及地点:随机分组,动物实验观察,于2006-08/2007-08在解放军第三军医大学大坪医院野战外科研究所完成。材料:纳入健康雄性SD大鼠104只,随机分为3组:正常对照组8只,爆炸损伤组48只,复合损伤组48只。方法:将大鼠按模拟战位固定于模拟舱室内,0.4g黑索金点纸质爆源置于舱室中心爆炸,模拟冲击波烟雾复合伤模型。复合损伤组大鼠在爆炸后放置100s取出,爆炸损伤组大鼠爆炸后立即取出,正常对照组不做处理。主要观察指标:大鼠于伤后1,3,6,12,24,72h再次麻醉后行动脉插管观察心功能变化,并采血,运用双抗体夹心法检测血浆脑钠素蛋白水平,取心脏病理标本观察心肺组织病理变化。结果:与正常对照组比较,爆炸损伤组和复合损伤组大鼠心肺病理形态学,均有明显改变,且复合损伤组比爆炸损伤组损伤严重。爆炸损伤组和复合损伤组大鼠血浆脑钠肽在各时相点均高于正常对照组(P<0.05),复合损伤组高于爆炸损伤组(P<0.05)。左室内压最大下降速率、左室收缩压、平均动脉压与脑钠肽质量浓度的变化一致,而左室内压最大上升速率则呈负相关性。结论:脑钠肽可做为冲击波烟雾复合伤早期检测损伤指标,舱内爆炸烟雾复合伤对心肺损伤较单纯爆炸损伤更加严重。