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A new procedure is presented for the synthesis of diagonal compensators for N × N linear multivariable systems that are free of fixed modes with respect to constant diagonal output feedbacks. The synthesis procedure employs simple polynomial algebra and it is in the form of an N-step algorithm. The geometric configurations 2N- and 2N-cells in N-space are shown to be especially suitable for visualizing diagonal feedback and aiding the application of the synthesis algorithm. 相似文献
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E Drosopoulou M Tsiafouli P Mavragani-Tsipidou ZG Scouras 《Canadian Metallurgical Quarterly》1997,106(1):20-28
Myasthenia gravis (MG) is a T-cell-regulated autoimmune disease in which a pathological autoantibody response is mounted against the nicotinic acetylcholine receptor of the neuromuscular junction. Our laboratory previously identified a T cell epitope, p195-212, derived from the human acetylcholine receptor alpha subunit, which triggered PBL to proliferate from about 70% of MG patients tested. p195-212 was also found to be an immunodominant T cell epitope in SJL mice and a cryptic epitope in C3H.SW mice. Inoculation of naive SJL mice with cells from a p195-212-specific syngeneic T cell line caused MG-related autoimmune manifestations in those mice. In these studies we analyzed TCR alpha and beta chain sequences used by T cell lines and clones from both high- and low-responder mouse strains in response to p195-212. T cell lines generated from either strain expressed single TCR V beta gene segments (V beta 17 in SJL mice and V beta 8 in C3H.SW mice). By deleting V beta 17-expressing T cells in p195-212-immunized SJL mice we established a T cell line that expressed the V beta 6 gene product, suggesting that SJL mice are not limited to using a single V beta gene segment in response to p195-212. In addition, we found that N- and/or C-terminal-truncated peptides of p195-212, presented under the same culture conditions to different clones bearing the same TCR alpha beta chain, could elicit very different proliferative responses from the clones. Thus, even within a constrained system, factors other than TCR sequence contribute to the differential stimulation of T cell responses. 相似文献
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Adherent cells were released from human peripheral blood mononuclears and the remaining mononuclears were separated by the density gradient centrifugation on percoll. Five fractions obtained were tested for cytotoxicity against K-562 and HeLa tumour target cells. Cell morphology and reactivity to some monoclonal antibodies were also studied. Fractions 2 and 3 were enriched by large granular lymphocytes (LGL) and BMA-070 positive cells and showed increased cytotoxicity only to K-562 target cells, while fraction 1 contained 9.5% of monocytes, but no LGL, and showed increased cytotoxicity against both K-562 and HeLa target cells. 相似文献