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71.
The aim of this paper is to discuss the Cauchy problem of the quasilinear hyperbolic equation of the form
ut+x(um)=up  相似文献   
72.
为了进一步降低器件的导通电阻,提出了一种新型的ACCUFET结构——栅增强功率ACCUFET(GE-ACCUFET)。这种器件同时具有普通ACCUFET和GE-UMOS的优点,而且导通电阻比这两种器件都要低。设计了一个击穿电压约106 V,导通电阻为2.18×10-4Ω.cm2的栅增强型功率ACCUFET器件(GE-ACCUFET)。将这种新型器件与GE-UMOS、普通ACCUFET进行对比,并进一步研究器件的结构参数对器件性能的影响。通过ATLAS仿真软件的建模仿真得到的数据显示,新型器件的导通电阻与GE-UMOS、普通ACCUFET相比,均有大幅度的降低。仿真还得到了器件导通电阻和击穿电压与结构参数H,D,α的函数关系,这对器件的生产制造有一定的指导作用。  相似文献   
73.
The occurrence and development of neurodegenerative diseases is related to a variety of physiological and pathological changes. Neuroinflammation is one of the major factors that induces and aggravates neurodegenerative diseases. The most important manifestation of neuroinflammation is the activation of microglia. Therefore, inhibiting the abnormal activation of microglia is an important way to alleviate the occurrence of neuroinflammatory diseases. In this research, the inhibitory effect of tabersonine (Tab) on neuroinflammation was evaluated by establishing the BV2 neuroinflammation model induced by lipopolysaccharide (LPS). It was found that Tab significantly inhibited the production and expression of nitric oxide (NO), interleukin-1β (IL-1β), tumor necrosis factor-α (TNF-α), interleukin-6 (IL-6), and reactive oxygen species (ROS) in BV-2 cells stimulated by LPS. In addition, Tab can also inhibit the activation of nuclear factor-κB (NF-κB) induced by LPS, thus regulating inflammatory mediators such as inducible nitric oxide synthase (iNOS). These results indicated that Tab regulated the release of inflammatory mediators such as NO, IL-1β, TNF-α, and IL-6 by inhibiting NF-κB signaling pathway, and exerting its anti-neuroinflammatory effect. This is the first report regarding the inhibition on LPS-induced neuroinflammation in BV2 microglia cells of Tab, which indicated the drug development potential of Tab for the treatment of neurodegenerative diseases.  相似文献   
74.
Lindera obtusiloba Blume (family, Lauraceae), native to Northeast Asia, has been used traditionally in the treatment of trauma and neuralgia. In this study, we investigated the neuroinflammatory effect of methanol extract of L. obtusiloba stem (LOS-ME) in a scopolamine-induced amnesia model and lipopolysaccharide (LPS)-stimulated BV2 microglia cells. LOS-ME downregulated the expression of inducible nitric oxide synthase (iNOS), cyclooxygenase (COX)-2, inflammatory cytokines, and inhibited the phosphorylation of nuclear factor kappa-B (NF-ĸB) and extracellular signal-regulated kinase (ERK) in LPS-stimulated BV2 cells. Male C57/BL6 mice were orally administered 20 and 200 mg/kg of LOS-ME for one week, and 2 mg/kg of scopolamine was administered intraperitoneally on the 8th day. In vivo behavioral experiments (Y-maze and Morris water maze test) confirmed that LOS-ME alleviated cognitive impairments induced by scopolamine and the amount of iNOS expression decreased in the hippocampus of the mouse brain. Microglial hyper-activation was also reduced by LOS-ME pretreatment. These findings suggest that LOS-ME might have potential in the treatment for cognitive improvement by regulating neuroinflammation.  相似文献   
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