辐照型电子直线加速器的应用已经越来越广泛,但是其辐射屏蔽优化一直是需要解决的问题,所以设计出既经济又有效的屏蔽方法是非常有意义的。本文叙述了对一台10 MeV的辐照型电子直线加速器迷道出口的剂量率所进行的经验公式计算和蒙特卡...辐照型电子直线加速器的应用已经越来越广泛,但是其辐射屏蔽优化一直是需要解决的问题,所以设计出既经济又有效的屏蔽方法是非常有意义的。本文叙述了对一台10 MeV的辐照型电子直线加速器迷道出口的剂量率所进行的经验公式计算和蒙特卡罗(Monte Carlo,Fluka)模拟,结合伽马探测器和微型数据采集器Mini-DDL(Mini Digital Data Logging)的连续实时测量结果进行了对比分析。分析结果显示,只要在迷道门处增加一个拐弯,就增加一次反散射,出口处的剂量率会下降一个量级以上,使其不仅低于剂量限值而且合理地达到尽可能低。这个结果是在基本没有增加额外成本的基础上实现的,符合辐射防护ALARA(as low as reasonably achievable)原则,为以后加速器的屏蔽设计提供了很好的参考。展开更多
Objective Endogenous nitric oxide （NO） has been implicated in the regulation of neuronal activity which mediates cardiovascular reflexes. However, there is controversy concerning the role of NO in the nucleus tractu...Objective Endogenous nitric oxide （NO） has been implicated in the regulation of neuronal activity which mediates cardiovascular reflexes. However, there is controversy concerning the role of NO in the nucleus tractus solitarius （NTS）. The present study aims to elucidate the possible physiological role of endogenous NO in modulating the excitatory vagal afferent input to NTS neurons. Methods All the experiments in the rat were conducted under anaesthetic conditions. Ionophoresis method was used for the application of NO donor or nitric oxide synthase （NOS） inhibitor, and single unit recording method was employed to detect the effects of these applications on vagal afferentor cardio-pulmonary C-fibre reflex-evoked neuronal excitation in NTS. Results Ionophoresis applications of L-arginine （L-Arg）, a substrate of NOS, and sodium nitroprusside （SNP）, a NO donor, both attenuated the vagal afferent-evoked discharge by （51.5±7.6）% （n = 17） and （68.3±7.1）% （n = 9）, respectively. In contrast, application of D-Arg at the same current exerted no overall effect on this input. Also, both L-Arg and SNP inhibited spontaneous firing of most of the recorded neurons. In contrast, ionophoresis application of NG-nitro-Larginine methyl ester （L-NAME） enhanced vagal afferent-evoked excitation by （66.3±11.4）% （n = 7）. In addition, ionophoresis application of L-Arg and SNP significantly attenuated cardio-pulmonary C-fibre reflex-induced excitation in the tested NTS neurons. Conclusion Activation of local NO pathway in the NTS could suppress vagal afferent-evoked excitation, suggesting that NO is an important neuromodulator of visceral sensory input in the NTS.展开更多
OBJECTIVE:To observe the effect of tetrahydroxy stilbene glucoside(TSG) on the behavior of APP695V717 I transgenic mouse models and the expression of autophagy-associated proteins Beclin-1and LC3-Ⅱ.METHODS:Forty 3-mo...OBJECTIVE:To observe the effect of tetrahydroxy stilbene glucoside(TSG) on the behavior of APP695V717 I transgenic mouse models and the expression of autophagy-associated proteins Beclin-1and LC3-Ⅱ.METHODS:Forty 3-month-old APP695V717 I transgenic mice were randomized equally into either a TSG group(n = 20) or a model group(n = 20).A normal control group consisted of C57BL/6J mice of the same age and background(n = 20).The TSG group received TSG intragastric administration for1 month.Behavior was measured using the Morris water maze and the Y-maze tests.Changes in protein expression and mRNA of autophagy-associated Beclin-1 and LC3-Ⅱ in mice hippocampus were detected by western blot and Reverse Transcription-Polymerase Chain Reaction(RT-PCR) analyses.RESULTS:The number of electric-stimulus escapes significantly increased and the Morris water maze test showed prolonged escape latency,greater swimming distance,less time taken to cross the exact former platform location in the model group,and increased mRNA and protein expressions of Beclin-1 and LC3-Ⅱ compared with the control group(P < 0.05).The TSG group showed a decrease in the number of electric-stimulus escapes,shorter escape latency and swimming distance,greater time taken to cross the exact former platform location,and decreased mRNA and protein expressions of Beclin-1 and LC3-Ⅱ compared with the model group(P< 0.05).CONCLUSION:These results indicate that tetrahydroxy stilbene glucoside can decrease expressions of Beclin-1 and LC3-Ⅱ in the autophagy pathway.It can attenuate injury to endoplasmic reticulum functions caused by Ab neurotoxicity,improving learning,memorizing,and spatial orientation behavior in mice.展开更多
文摘辐照型电子直线加速器的应用已经越来越广泛,但是其辐射屏蔽优化一直是需要解决的问题,所以设计出既经济又有效的屏蔽方法是非常有意义的。本文叙述了对一台10 MeV的辐照型电子直线加速器迷道出口的剂量率所进行的经验公式计算和蒙特卡罗(Monte Carlo,Fluka)模拟,结合伽马探测器和微型数据采集器Mini-DDL(Mini Digital Data Logging)的连续实时测量结果进行了对比分析。分析结果显示,只要在迷道门处增加一个拐弯,就增加一次反散射,出口处的剂量率会下降一个量级以上,使其不仅低于剂量限值而且合理地达到尽可能低。这个结果是在基本没有增加额外成本的基础上实现的,符合辐射防护ALARA(as low as reasonably achievable)原则,为以后加速器的屏蔽设计提供了很好的参考。
基金supported by Chongqing Science and Technology Commission (No.CHTC2007BA5025)Shanghai Pujiang Program (No.07PJ14015)Chongqing Educational Department (No. KJ0707021)
文摘Objective Endogenous nitric oxide （NO） has been implicated in the regulation of neuronal activity which mediates cardiovascular reflexes. However, there is controversy concerning the role of NO in the nucleus tractus solitarius （NTS）. The present study aims to elucidate the possible physiological role of endogenous NO in modulating the excitatory vagal afferent input to NTS neurons. Methods All the experiments in the rat were conducted under anaesthetic conditions. Ionophoresis method was used for the application of NO donor or nitric oxide synthase （NOS） inhibitor, and single unit recording method was employed to detect the effects of these applications on vagal afferentor cardio-pulmonary C-fibre reflex-evoked neuronal excitation in NTS. Results Ionophoresis applications of L-arginine （L-Arg）, a substrate of NOS, and sodium nitroprusside （SNP）, a NO donor, both attenuated the vagal afferent-evoked discharge by （51.5±7.6）% （n = 17） and （68.3±7.1）% （n = 9）, respectively. In contrast, application of D-Arg at the same current exerted no overall effect on this input. Also, both L-Arg and SNP inhibited spontaneous firing of most of the recorded neurons. In contrast, ionophoresis application of NG-nitro-Larginine methyl ester （L-NAME） enhanced vagal afferent-evoked excitation by （66.3±11.4）% （n = 7）. In addition, ionophoresis application of L-Arg and SNP significantly attenuated cardio-pulmonary C-fibre reflex-induced excitation in the tested NTS neurons. Conclusion Activation of local NO pathway in the NTS could suppress vagal afferent-evoked excitation, suggesting that NO is an important neuromodulator of visceral sensory input in the NTS.
基金the National Natural Science Foundation of China(Effect of Tetrahydroxy Stilbene Glycoside on Endoplasmic Reticulum Stress Induced byβ-amyloid in Alzheimer's Disease,No.81303097 and the effect of Curcumin on Alzheimer's Disease based on PPARγ-HSP70 Pathway,No.81373794)
文摘OBJECTIVE:To observe the effect of tetrahydroxy stilbene glucoside(TSG) on the behavior of APP695V717 I transgenic mouse models and the expression of autophagy-associated proteins Beclin-1and LC3-Ⅱ.METHODS:Forty 3-month-old APP695V717 I transgenic mice were randomized equally into either a TSG group(n = 20) or a model group(n = 20).A normal control group consisted of C57BL/6J mice of the same age and background(n = 20).The TSG group received TSG intragastric administration for1 month.Behavior was measured using the Morris water maze and the Y-maze tests.Changes in protein expression and mRNA of autophagy-associated Beclin-1 and LC3-Ⅱ in mice hippocampus were detected by western blot and Reverse Transcription-Polymerase Chain Reaction(RT-PCR) analyses.RESULTS:The number of electric-stimulus escapes significantly increased and the Morris water maze test showed prolonged escape latency,greater swimming distance,less time taken to cross the exact former platform location in the model group,and increased mRNA and protein expressions of Beclin-1 and LC3-Ⅱ compared with the control group(P < 0.05).The TSG group showed a decrease in the number of electric-stimulus escapes,shorter escape latency and swimming distance,greater time taken to cross the exact former platform location,and decreased mRNA and protein expressions of Beclin-1 and LC3-Ⅱ compared with the model group(P< 0.05).CONCLUSION:These results indicate that tetrahydroxy stilbene glucoside can decrease expressions of Beclin-1 and LC3-Ⅱ in the autophagy pathway.It can attenuate injury to endoplasmic reticulum functions caused by Ab neurotoxicity,improving learning,memorizing,and spatial orientation behavior in mice.
