In research of the characteristics of the cavity evolution, the pressure, and the liquid spurt in hydrodynamic ram, the experiment of the high-velocity fragment impacting the water-filled container had been conducted....In research of the characteristics of the cavity evolution, the pressure, and the liquid spurt in hydrodynamic ram, the experiment of the high-velocity fragment impacting the water-filled container had been conducted. The relationships between the above three characteristics have been researched. The evolution of the cavity can be divided into three processes according to its shape characteristics. The first liquid spurt occurred in Process Ⅱ and the rest of it occurred in Process Ⅲ. The duration of the second liquid spurt is longer than the first liquid spurt. When the impact velocity of the fragment is less than996 m/s, the velocity of the second liquid spurt is the highest. When the velocity of the fragment is greater than 996 m/s, the velocity of the first liquid spurt is the highest. The maximum velocities of the first and second liquid spurt are 111 m/s and 94 m/s respectively. The pressure fluctuated sharply in Processes Ⅰ and Ⅲ. The maximum peak pressures in the shock and the cavity oscillation phases are15.51 MPa and 7.96 MPa respectively. The time interval of the two adjacent pressure pulses increases with the increase of the fragment velocity.展开更多
Objective:This study aims to investigate the degree of biocompatibility and neuroregeneration of a polymer tube,poly-3-hydroxyoctanoate(PHO)in nerve gap repair.Methods:Forty Wistar Albino male rats were randomized int...Objective:This study aims to investigate the degree of biocompatibility and neuroregeneration of a polymer tube,poly-3-hydroxyoctanoate(PHO)in nerve gap repair.Methods:Forty Wistar Albino male rats were randomized into two groups:autologous nerve gap repair group and PHO tube repair group.In each group,a 10-mm right sciatic nerve defect was created and reconstructed accordingly.Neuroregeneration was studied by sciatic function index(SFI),electromyography,and immunohistochemical studies on Days 7,21,45 and 60 of implantation.Biocompatibility was analyzed by the capsule formation around the conduit.Biodegradation was analyzed by the molecular weight loss in vivo.Results:Electrophysiological and histomorphometric assessments demonstrated neuroregeneration in both groups over time.In the experimental group,a straight alignment of the Schwann cells parallel to the axons was detected.However,autologous nerve graft seems to have a superior neuroregeneration compared to PHO grafts.Minor biodegradation was observed in PHO conduit at the end of 60 d.Conclusions:Although neuroregeneration is detected in PHO grafts with minor degradation in 60 d,autologous nerve graft is found to be superior in axonal regeneration compared to PHO nerve tube grafts.PHO conduits were found to create minor inflammatory reaction in vivo,resulting in good soft tissue response.展开更多
基金the National Natural Science Foundation of China(Grant No.11572159)the National Defense Science and Technology Foundational Enhancement Program Technology Field Foundation(No.2020-JCJQ-JJ-401)for providing the financial support for this study.
文摘In research of the characteristics of the cavity evolution, the pressure, and the liquid spurt in hydrodynamic ram, the experiment of the high-velocity fragment impacting the water-filled container had been conducted. The relationships between the above three characteristics have been researched. The evolution of the cavity can be divided into three processes according to its shape characteristics. The first liquid spurt occurred in Process Ⅱ and the rest of it occurred in Process Ⅲ. The duration of the second liquid spurt is longer than the first liquid spurt. When the impact velocity of the fragment is less than996 m/s, the velocity of the second liquid spurt is the highest. When the velocity of the fragment is greater than 996 m/s, the velocity of the first liquid spurt is the highest. The maximum velocities of the first and second liquid spurt are 111 m/s and 94 m/s respectively. The pressure fluctuated sharply in Processes Ⅰ and Ⅲ. The maximum peak pressures in the shock and the cavity oscillation phases are15.51 MPa and 7.96 MPa respectively. The time interval of the two adjacent pressure pulses increases with the increase of the fragment velocity.
文摘Objective:This study aims to investigate the degree of biocompatibility and neuroregeneration of a polymer tube,poly-3-hydroxyoctanoate(PHO)in nerve gap repair.Methods:Forty Wistar Albino male rats were randomized into two groups:autologous nerve gap repair group and PHO tube repair group.In each group,a 10-mm right sciatic nerve defect was created and reconstructed accordingly.Neuroregeneration was studied by sciatic function index(SFI),electromyography,and immunohistochemical studies on Days 7,21,45 and 60 of implantation.Biocompatibility was analyzed by the capsule formation around the conduit.Biodegradation was analyzed by the molecular weight loss in vivo.Results:Electrophysiological and histomorphometric assessments demonstrated neuroregeneration in both groups over time.In the experimental group,a straight alignment of the Schwann cells parallel to the axons was detected.However,autologous nerve graft seems to have a superior neuroregeneration compared to PHO grafts.Minor biodegradation was observed in PHO conduit at the end of 60 d.Conclusions:Although neuroregeneration is detected in PHO grafts with minor degradation in 60 d,autologous nerve graft is found to be superior in axonal regeneration compared to PHO nerve tube grafts.PHO conduits were found to create minor inflammatory reaction in vivo,resulting in good soft tissue response.
