目的探讨脑血流自动调节范围内稳定脑血流速度的血流动力学因素。方法利用经颅多普勒检测SD大鼠大脑中动脉的血流速度(cerebral blood flow velocity,CBFV),并同步记录有创动脉血压,绘制自动调节曲线,判断脑血流自动调节上、下限。计算...目的探讨脑血流自动调节范围内稳定脑血流速度的血流动力学因素。方法利用经颅多普勒检测SD大鼠大脑中动脉的血流速度(cerebral blood flow velocity,CBFV),并同步记录有创动脉血压,绘制自动调节曲线,判断脑血流自动调节上、下限。计算临界关闭压(critical closing pressure,CCP)和血管面积阻力指数(resistance area product,RAP)。分析CCP、RAP与平均动脉压(mean artery blood pressure,MABP)之间的关系。结果动脉血压升高或降低过程中,正常大鼠脑血流自动调节上、下限分别为148.12±7.49 mm Hg、62.96±3.34 mm Hg。脑血流自动调节范围内,CBFV随动脉血压改变轻微(每10 mm Hg MABP,升压:0.65±0.27 cm/s;降压:0.43±0.23 cm/s),而CCP和RAP则随动脉血压明显改变(每10 mm Hg MABP,升压:4.60±1.06 mm Hg、0.11±0.04mm Hg;降压:6.74±0.59 mm Hg、0.09±0.02 mm Hg)。虽然CBFV、CCP、RAP的变化都与MABP相关,但控制CBFV的变动后,CCP和RAP随MABP改变相关性更加明显,其中CCP的变化幅度以及与MABP的相关性明显大于RAP(升压:Beta=0.561、0.418;降压:Beta=0.694、0.266,P均=0.000)。结论大鼠脑血流自动调节有效范围内,脑血流的稳定主要通过CCP和RAP改变对抗动脉血压的变动而实现,尤其是CCP相应升高或降低。展开更多
In this work, the study of the influences of lifetime, doping concentration and absorption layer thickness to resistant- area product (R0A) and quantum efficiency of Pb1-xSnxSe photovoltaic detector are presented. Thr...In this work, the study of the influences of lifetime, doping concentration and absorption layer thickness to resistant- area product (R0A) and quantum efficiency of Pb1-xSnxSe photovoltaic detector are presented. Three fundamental current mechanisms including diffusion, generation-recombination, and tunneling models are considered. Using optimal doping concentration and absorption layer thickness parameters, the calculated detectivity (D*) of Pb1-xSnxSe photovoltaic detector is over 1012 cm Hz1/2/W.展开更多
文摘目的探讨脑血流自动调节范围内稳定脑血流速度的血流动力学因素。方法利用经颅多普勒检测SD大鼠大脑中动脉的血流速度(cerebral blood flow velocity,CBFV),并同步记录有创动脉血压,绘制自动调节曲线,判断脑血流自动调节上、下限。计算临界关闭压(critical closing pressure,CCP)和血管面积阻力指数(resistance area product,RAP)。分析CCP、RAP与平均动脉压(mean artery blood pressure,MABP)之间的关系。结果动脉血压升高或降低过程中,正常大鼠脑血流自动调节上、下限分别为148.12±7.49 mm Hg、62.96±3.34 mm Hg。脑血流自动调节范围内,CBFV随动脉血压改变轻微(每10 mm Hg MABP,升压:0.65±0.27 cm/s;降压:0.43±0.23 cm/s),而CCP和RAP则随动脉血压明显改变(每10 mm Hg MABP,升压:4.60±1.06 mm Hg、0.11±0.04mm Hg;降压:6.74±0.59 mm Hg、0.09±0.02 mm Hg)。虽然CBFV、CCP、RAP的变化都与MABP相关,但控制CBFV的变动后,CCP和RAP随MABP改变相关性更加明显,其中CCP的变化幅度以及与MABP的相关性明显大于RAP(升压:Beta=0.561、0.418;降压:Beta=0.694、0.266,P均=0.000)。结论大鼠脑血流自动调节有效范围内,脑血流的稳定主要通过CCP和RAP改变对抗动脉血压的变动而实现,尤其是CCP相应升高或降低。
文摘In this work, the study of the influences of lifetime, doping concentration and absorption layer thickness to resistant- area product (R0A) and quantum efficiency of Pb1-xSnxSe photovoltaic detector are presented. Three fundamental current mechanisms including diffusion, generation-recombination, and tunneling models are considered. Using optimal doping concentration and absorption layer thickness parameters, the calculated detectivity (D*) of Pb1-xSnxSe photovoltaic detector is over 1012 cm Hz1/2/W.
