Based on the momentum conservation approach, a theoretical model was developed to predict the superficial liquid velocity, and a correlation equation was established to calculate the gas holdup of an annular external-...Based on the momentum conservation approach, a theoretical model was developed to predict the superficial liquid velocity, and a correlation equation was established to calculate the gas holdup of an annular external-loop airlift reactor(AELAR)in the bubble flow and developing slug flow pattern. Experiments were performed by using tap-water and silicone oil with the viscosity of 2.0 mm^2/s(2cs-SiO)and 5.0 mm^2/s(5cs-SiO)as liquid phases. The effects of liquid viscosity and flow pattern on the AELAR performance were investigated. The predictions of the proposed model were in good agreement with the experimental results of the AELAR. In addition, the comparison of the experimental results shows that the proposed model has good accuracy and could be used to predict the gas holdup and liquid velocity of an AELAR operating in bubble and developing flow pattern.展开更多
Objective： To establish a good recoverable rat model of cardiopulmonary bypass （CPB） to lay the foundation for studying the pathophysiology of CPB. Methods： Twenty adult male Sprague-Dawley rats weighing 480 g &#...Objective： To establish a good recoverable rat model of cardiopulmonary bypass （CPB） to lay the foundation for studying the pathophysiology of CPB. Methods： Twenty adult male Sprague-Dawley rats weighing 480 g ±20 g were randomly divided into CPB group （n = 10 ） and Sham group （ n = 10 ）. All rats were anaesthetized, intubated and ventilated. The carotid artery and jugular vein were cannulated. The blood was drained from the right atrium via the right jugular vein and further transferred by a miniaturized roller pump to a hollow fiber oxgenator and back to the rat via the left carotid artery. Priming consisted of 8 ml of homologous blood and 6 ml of colloid. The surface of the hollow fiber oxgenator was 0.075 m^2. Rats were catheterized and brought in bypass for 120 rain at a flow rate of 100-120 ml/kg/min. Oxygen flow/ perfnsion flow was 0.8 to 1.0, the mean arterial pressure （MAP） kept in 60-80 mmHg. Blood gas analysis, lactate dehydrogenase （LDH）, and survival rate were examined subsequently. Results： AH CPB rats recovered from the operative process without incident and remained uneventful within one week. Normal cardiac function after successful weaning was confirmed by electrocardiography and blood pressure measurements. MAP remained stable. The results of blood gas analysis at different time points were within a normal range. No significant haemolysis could be detected in the given time frame under bypass condition by using LDH. Conclusions： The rat model of CPB can principally simulate the clinical setting of human CPB. The nontrausthoracic model is easy to establish and is associated with excellent recovery. This well reproducible model may open the field for various studies on pathophysiological process of CPB and also of systemic ischemia-reperfusion injury in vivo.展开更多
基金Supported by the National Natural Science Foundation of China(No.51478297)Program of Introducing Talents of Discipline(No.B13011)
文摘Based on the momentum conservation approach, a theoretical model was developed to predict the superficial liquid velocity, and a correlation equation was established to calculate the gas holdup of an annular external-loop airlift reactor(AELAR)in the bubble flow and developing slug flow pattern. Experiments were performed by using tap-water and silicone oil with the viscosity of 2.0 mm^2/s(2cs-SiO)and 5.0 mm^2/s(5cs-SiO)as liquid phases. The effects of liquid viscosity and flow pattern on the AELAR performance were investigated. The predictions of the proposed model were in good agreement with the experimental results of the AELAR. In addition, the comparison of the experimental results shows that the proposed model has good accuracy and could be used to predict the gas holdup and liquid velocity of an AELAR operating in bubble and developing flow pattern.
文摘Objective： To establish a good recoverable rat model of cardiopulmonary bypass （CPB） to lay the foundation for studying the pathophysiology of CPB. Methods： Twenty adult male Sprague-Dawley rats weighing 480 g ±20 g were randomly divided into CPB group （n = 10 ） and Sham group （ n = 10 ）. All rats were anaesthetized, intubated and ventilated. The carotid artery and jugular vein were cannulated. The blood was drained from the right atrium via the right jugular vein and further transferred by a miniaturized roller pump to a hollow fiber oxgenator and back to the rat via the left carotid artery. Priming consisted of 8 ml of homologous blood and 6 ml of colloid. The surface of the hollow fiber oxgenator was 0.075 m^2. Rats were catheterized and brought in bypass for 120 rain at a flow rate of 100-120 ml/kg/min. Oxygen flow/ perfnsion flow was 0.8 to 1.0, the mean arterial pressure （MAP） kept in 60-80 mmHg. Blood gas analysis, lactate dehydrogenase （LDH）, and survival rate were examined subsequently. Results： AH CPB rats recovered from the operative process without incident and remained uneventful within one week. Normal cardiac function after successful weaning was confirmed by electrocardiography and blood pressure measurements. MAP remained stable. The results of blood gas analysis at different time points were within a normal range. No significant haemolysis could be detected in the given time frame under bypass condition by using LDH. Conclusions： The rat model of CPB can principally simulate the clinical setting of human CPB. The nontrausthoracic model is easy to establish and is associated with excellent recovery. This well reproducible model may open the field for various studies on pathophysiological process of CPB and also of systemic ischemia-reperfusion injury in vivo.
