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141.
We propose a new generic flow formulation for Failure-Independent Path-Protecting (FIPP) p-cycles subject to multiple failures. While our new model resembles the decomposition model formulation proposed by Orlowski and Pioro (Networks, 2011) in the case of classical shared path protection, its originality lies in its adaptation to FIPP p-cycles. When adapted to that last pre-configured pre-cross connected protection scheme, the bandwidth sharing constraints must be handled in a different way in order to take care of the sharing along the FIPP p-cycles. It follows that, instead of a polynomial-time solvable pricing problem as in the model of Orlowski and Pioro (Networks, 2011), we end up with a much more complex pricing problem, which has an exponential number of constraints due to some subtour elimination constraints. Consequently, in order to efficiently solve the pricing problem, we consider: (i) a hierarchical decomposition of the original pricing problem; (ii) heuristics in order to go around the large number of constraints in the pricing problem. Performance evaluation is made in the case of FIPP p-cycles subject to dual failures. For small to medium size networks, the proposed model remains fairly scalable for increasing percentages of dual failures, and requires much less bandwidth than p-cycle protection schemes (ratio varies from 2 to 4). For larger networks, heuristics are required in order to keep computing times reasonable. In the particular case of single link failures, it compares very favorably (5 to 10 % of bandwidth saving) to the previously proposed column generation ILP model of Rocha, Jaumard and Stidsen (Telecommun. Syst., 2012). 相似文献
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In presenting a unifying concept for chronic inflammation and lymphoid organogenesis, we suggest that lymphotoxin's (LT, LT-alpha, TNF-beta) crucial role in these processes is pivotal and similar. Chronic inflammatory lesions that developed in the kidney and pancreas at the sites of transgene expression in rat insulin promoter-LT (RIP-LT) mice resembled lymph nodes with regard to cellular composition (T cells, B cells, plasma cells, and antigen-presenting cells), delineated T and B cell areas, primary and secondary follicles, characteristic morphologic and antigenic (ICAM-1, VCAM-1, MAdCAM-1, and PNAd) features of high endothelial venules, and ability to respond to antigen and undergo Ig class switching when obtained from mice immunized with SRBC. The vascular changes, with the exception of PNAd, appear to be the direct consequence of transgene derived LT expression, as they were also observed in RIP-LT mice lacking mature T and B cells. These data show that LT-induced chronic inflammation has the characteristics of organized lymphoid tissue. 相似文献
144.
An alkylation method of docetaxel at the C-10 position has been established by a radical coupling reaction using a 10-xanthate derivative of 7-O-TES-10-deacetylbaccatin III and appropriate alkenes. In addition the cytotoxic activity of 10-alkylated docetaxel analogs was evaluated. Among these analogs, a derivative having a methoxycarbonyl group at the end of the alkyl moiety exhibited more potent cytotoxic activity than docetaxel. 相似文献
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LE Pyle WH Sawyer Y Fujiwara A Mitchell NH Fidge 《Canadian Metallurgical Quarterly》1996,35(37):12046-12052
Utilizing the Escherichia coli/pGex vector expression system incorporating a thrombin cleavage site, full-length (residues -6-243) and truncated forms of proapolipoprotein AI (proapoAI), terminating at amino acid residues 222, 210, 150, and 135, were purified to levels of at least 5 mg/L, after thrombin cleavage. Assessed by circular dichroism, the helical contents of L-alpha-dimyristoylphosphatidylcholine-associated forms of human plasma-derived apolipoprotein AI (apoAI) and recombinant proapoAI were comparable, being 69% and 65%, respectively. Circular dichroism measurements of the lipid-associated complexes of the truncated forms showed that between the sequence of residues 150-222 no additional helicity was gained until the carboxyl-terminal sequence was present in the molecule, indicating that the carboxyl terminus of the protein is required for the formation of helix within this central region. While tryptophan residues were more than 86% accessible, as assessed by iodide quenching, in the two truncated forms, proapoAI-6-135 and proapoAI-6-150, for both free and complexed protein, this figure fell to about 50% for full-length recombinant proapoAI, further indicating the influence of the carboxyl terminus on the structure of the whole protein. While cross-linking human plasma apoAI in solution with dithiobis-(succinimidyl propionate) revealed high molecular weight oligomers by sodium dodecyl sulfate-polyacrylamide gel electrophoresis, recombinant proapoAI did not strongly form complexes larger than trimers. None of the truncated proapoAI molecules formed oligomers larger than trimers. The shortest form, proapoAI-6-135, only dimerized. Initial results from lecithin:cholesterol acyltransferase activation (apoAI peptide concentration 0.2 microM) indicated that truncation of the 21 carboxy-terminal amino acids resulted in a drop of approximately 53% in activation and 33 residues a drop of 67% relative to the full-length protein. Overall these results indicate the important influence of the carboxyl terminus on the structure of apoAI. 相似文献
147.
Malec D. Essolbi R. Hoang The-Giam Bui-Ai Garros B. 《Dielectrics and Electrical Insulation, IEEE Transactions on》1996,3(1):64-69
Transient currents in cross-linked polyethylene (XLPE) have been investigated by using different parameters: temperature T, electrical field Ep and hydrostatic pressure P. Anomalous discharging currents flowing in the same direction as charging currents were observed from T=30 to 70°C, P=0.1 to 30 MPa and Ep=13 to 33 kV/mm. The space charge was measured using the pressure wave propagation method (PWP). Theoretical calculation revealed that this anomalous behavior can result from charge migration under a partial blocking condition at the electrodes. We discuss theoretical results which are in reasonable agreement with our discharge current measurements 相似文献
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In many critical applications of digital systems, fault tolerance has been an essential architectural attribute for achieving high reliability. This paper considers the problem of determining the optimal number of redundant channels in a digital communication system. The expected system cost is obtained. We determine the number of redundant channels minimizing the expected system cost. A numerical example illustrates the techniques. 相似文献