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101.
Hyperphosphorylated tau is the major component of paired helical filaments in neurofibrillary lesions associated with Alzheimer's disease. Hyperphosphorylation reduces the affinity of tau for microtubules and is thought to be a critical event in the pathogenesis of this disease. Recently, glycogen-synthase kinase-3 has been shown to phosphorylate tau in vitro and in non-neuronal cells transfected with tau. The activity of glycogen-synthase kinase-3 can be down-regulated in response to insulin or insulin-like growth factor-1 through the activation of the phosphatidylinositol 3-kinase pathway. We therefore hypothesize that insulin or insulin-like growth factor-1 may affect tau phosphorylation through the inhibition of glycogen-synthase kinase-3 in neurons. Using cultured human neuronal NT2N cells, we demonstrate that glycogen-synthase kinase-3 phosphorylates tau and reduces its affinity for microtubules and that insulin and insulin-like growth factor-1 stimulation reduces tau phosphorylation and promotes tau binding to microtubules. We further demonstrate that these effects of insulin and insulin-like growth factor-1 are mediated through the inhibition of glycogen-synthase kinase-3 via the phosphatidylinositol 3-kinase/protein kinase B signaling pathway. 相似文献
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研究了铁钴钒软磁合金的铁芯损耗,发现铁芯损耗谱具有分形结构。讨论了带材厚度和磁感应强度对分形维数Df的影响。 相似文献
104.
For pt.I see IEEE Trans. Neural Networks, vol.1, p.167-78 (1990). Parallel, self-organizing, hierarchical neural networks (PSHNNs) involve a number of stages with error detection at the end of each stage, i.e., rejection of error-causing vectors, which are then fed into the next stage after a nonlinear transformation. The stages operate in parallel during testing. Statistical properties and the mechanisms of vector rejection of the PSHNN are discussed in comparison to the maximum likelihood method and the backpropagation network. The PSHNN is highly fault tolerant and robust against errors in the weight values due to the adjustment of the error detection bounds to compensate errors in the weight values. These properties are exploited to develop architectures for programmable implementations in which the programmable parts are reduced to on-off or bipolar switching operations for bulk computations and attenuators for pointwise operations 相似文献
105.
Jun-Hee Hong Jong-Keun Park 《Power Systems, IEEE Transactions on》1995,10(4):1789-1797
This paper presents a method of obtaining transmission network equivalents from the network's response to a pulse excitation signal. The proposed method is based on modal decomposition representation for the large-scale interconnected system. In this framework we use Prony analysis to identify the network function of the system and to decompose the large system into a parallel combination of simple first-order systems. As a result the network function of the transmission network can be identified easily, and a Thevenin-type of discrete-time filter model can be generated. It can reproduce the driving-point impedance characteristic of the network. Furthermore, the proposed model can be implemented into the EMTP in a direct manner. The simulation results with the full system representation and the developed equivalent system showed a good agreement 相似文献
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Gunapala S.D. Bundara S.V. Liu J.K. Winn Hong Mani Sundaram Maker P.D. Muller R.E. Shott C.A. Carralejo R. 《Electron Devices, IEEE Transactions on》1998,45(9):1890-1895
A 9-μm cutoff 640×486 snap-shot quantum well infrared photodetector (QWIP) camera has been demonstrated. The performance of this QWIP camera is reported including indoor and outdoor imaging. The noise equivalent differential temperature (NEΔT) of 36 mK has been achieved at 300 K background with f/2 optics. This is in good agreement with expected focal plane array sensitivity due to the practical limitations on charge handling capacity of the multiplexer, read noise, bias voltage, and operating temperature 相似文献
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