Background Baicalin has a significant anti-inflammation effect and is widely used in the clinical treatment of stroke. Most of the studies of Toll-like receptor 2/4 （TLR2/4） during cerebral ischemia had defined the...Background Baicalin has a significant anti-inflammation effect and is widely used in the clinical treatment of stroke. Most of the studies of Toll-like receptor 2/4 （TLR2/4） during cerebral ischemia had defined their specific expressions in microglia in hippocampus tissue. To explore the targets of baicalin in stroke, we detected the expressions of TLR2/4 in vitro/vivo.Methods By constructing a cerebral ischemia-reperfusion model in vivo and glucose oxygen deprivation model, we successfully induced neuron damage, then added baicalin and detected expressions of TLR2/4, nuclear factor-kB （NF-kB）, tumor necrosis factor-alpha （TNFα）, and interleukin-1β （IL-1β） in mRNA level and protein level.Results We found distinct upregulations of TLR2/4 and TNFα in both mRNA level and protein level in PC12 cells and primary neurons. Moreover, TLR2/4 and TNFα expressions were significantly higher in mice hippocampus treated with cerebral ischemia-reperfusion. Baicalin could downregulate the expressions of TLR2/4 and TNFα in the damaged cells and mice hippocampus effectively.Conclusions Neurons could respond to the damage and activate the related signal pathway directly. TLR2/4 responsed to the damage and sent the signal to downstream factor TNFα through activating NF-kB. Baicalin could inhibit the inflammatory reaction in neuron damage and TLR might be its targets, which explained why baicalin could widely be used in the clinical treatment of stroke.展开更多
针对2~4 GHz的超宽频带,提出了一种宽带接收机的前端设计方法,其中包括射频信道设计、频率合成器的设计以及基带电路设计。鉴于小型化的设计思想,射频前端采用零中频接收机的架构,使用LTCC滤波器实现噪声系数优于8 d B,输出三阶截断点优...针对2~4 GHz的超宽频带,提出了一种宽带接收机的前端设计方法,其中包括射频信道设计、频率合成器的设计以及基带电路设计。鉴于小型化的设计思想,射频前端采用零中频接收机的架构,使用LTCC滤波器实现噪声系数优于8 d B,输出三阶截断点优于27 d Bm（低噪声模式下）。频率合成器采用集成VCO的锁相环芯片ADF4351,实现单边带相位噪声优于-110 d Bc/Hz@200 k Hz。基带电路采用正交解调器ADL5380和12位双通道AD转换器AD9238,可实现带宽为20 MHz的I/Q双路同时解调。通过FPGA或DSP处理,可广泛用于便携式小型化的监测接收机或通信接收机。展开更多
A comparative study is conducted to compare the theory and application effect of two accident causation models, the human factors analysis and classification system（HFACS） and the accident causation ＂2-4＂ model（2...A comparative study is conducted to compare the theory and application effect of two accident causation models, the human factors analysis and classification system（HFACS） and the accident causation ＂2-4＂ model（24 Model）, as well as to provide a reference for safety researchers and accident investigators to select an appropriate accident analysis method. The two models are compared in terms of their theoretical foundations, cause classifications, accident analysis processes, application ranges, and accident prevention strategies. A coal and gas outburst accident is then analyzed using both models, and the application results are compared. This study shows that both the 24 Model and HFACS have strong theoretical foundations, and they can each be applied in various domains. In addition, the cause classification in HFACS is more practical, and its accident analysis process is more convenient. On the other hand, the 24 Model includes external factors, which makes the cause analysis more systematic and comprehensive. Moreover, the 24 Model puts forward more corresponding measures to prevent accidents.展开更多
基金This work was supported by grants from the National Natural Science Foundation of China （No. 30973896, No. 30801523, and No. 81073092） and the National S＆T Major Special Project for New Drug R＆D Program of China （No. 2009ZX09103-301, No. 2009ZX09502, No. 2009ZX09308-003, and No. 2011ZX09101- 002-11）.Acknowledgments： We thank specially all our colleagues in our laboratory.
文摘Background Baicalin has a significant anti-inflammation effect and is widely used in the clinical treatment of stroke. Most of the studies of Toll-like receptor 2/4 （TLR2/4） during cerebral ischemia had defined their specific expressions in microglia in hippocampus tissue. To explore the targets of baicalin in stroke, we detected the expressions of TLR2/4 in vitro/vivo.Methods By constructing a cerebral ischemia-reperfusion model in vivo and glucose oxygen deprivation model, we successfully induced neuron damage, then added baicalin and detected expressions of TLR2/4, nuclear factor-kB （NF-kB）, tumor necrosis factor-alpha （TNFα）, and interleukin-1β （IL-1β） in mRNA level and protein level.Results We found distinct upregulations of TLR2/4 and TNFα in both mRNA level and protein level in PC12 cells and primary neurons. Moreover, TLR2/4 and TNFα expressions were significantly higher in mice hippocampus treated with cerebral ischemia-reperfusion. Baicalin could downregulate the expressions of TLR2/4 and TNFα in the damaged cells and mice hippocampus effectively.Conclusions Neurons could respond to the damage and activate the related signal pathway directly. TLR2/4 responsed to the damage and sent the signal to downstream factor TNFα through activating NF-kB. Baicalin could inhibit the inflammatory reaction in neuron damage and TLR might be its targets, which explained why baicalin could widely be used in the clinical treatment of stroke.
文摘针对2~4 GHz的超宽频带,提出了一种宽带接收机的前端设计方法,其中包括射频信道设计、频率合成器的设计以及基带电路设计。鉴于小型化的设计思想,射频前端采用零中频接收机的架构,使用LTCC滤波器实现噪声系数优于8 d B,输出三阶截断点优于27 d Bm（低噪声模式下）。频率合成器采用集成VCO的锁相环芯片ADF4351,实现单边带相位噪声优于-110 d Bc/Hz@200 k Hz。基带电路采用正交解调器ADL5380和12位双通道AD转换器AD9238,可实现带宽为20 MHz的I/Q双路同时解调。通过FPGA或DSP处理,可广泛用于便携式小型化的监测接收机或通信接收机。
基金support from the State Key Program of the National Natural Science Foundation of China (No. 51534008)
文摘A comparative study is conducted to compare the theory and application effect of two accident causation models, the human factors analysis and classification system（HFACS） and the accident causation ＂2-4＂ model（24 Model）, as well as to provide a reference for safety researchers and accident investigators to select an appropriate accident analysis method. The two models are compared in terms of their theoretical foundations, cause classifications, accident analysis processes, application ranges, and accident prevention strategies. A coal and gas outburst accident is then analyzed using both models, and the application results are compared. This study shows that both the 24 Model and HFACS have strong theoretical foundations, and they can each be applied in various domains. In addition, the cause classification in HFACS is more practical, and its accident analysis process is more convenient. On the other hand, the 24 Model includes external factors, which makes the cause analysis more systematic and comprehensive. Moreover, the 24 Model puts forward more corresponding measures to prevent accidents.
