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991.
Zusammenfassung Die Infektion der Blätter vonCapsicum annuum undMangifera indica mit den BlattpilzenCurvularia ovoidea beziehungsweiselunata hat zur Folge, dass die freien Zucker Saccharose, Glukose und Fruktose verschwinden und dass der Gehalt an organischen Säuren (Apfelsäure, Zitronensäure, Oxalsäure) vermindert wird.  相似文献   
992.
Intestinal morphogenesis and differentiation are dependent on heterotypic cell interactions between embryonic epithelial cells (endoderm) and stromal cells (mesenchyme). Extracellular matrix molecules represent attractive candidates for regulators of these interactions. The structural and functional diversity of the extracellular matrix as intestinal development proceeds is demonstrated by 1) spatio-temporal specific expression of the classically described constituents, 2) the finding of laminin and collagen IV variants, 3) changes in the ratio of individual constituent chains, and 4) a stage-specific regulation of basement membrane molecule production, in particular by glucocorticoids. The orientation/assembly of these extracellular matrix molecules could direct precise cellular functions through interactions via integrin molecules. The involvement of extracellular matrix, and in particular basement membrane molecules in heterotypic cell interactions leading to epithelial cell differentiation, has been highlighted by the use of experimental models such as cocultures, hybrid intestines and antisense approaches. These models allowed us to conclude that a correct elaboration and assembly of the basement membrane, following close contacts between epithelial and fibroblastic cells, is necessary for the expression of differentiation markers such as digestive enzymes.  相似文献   
993.
Substance P and choline acetyltransferase have been localised in a small proportion of endothelial cells of rat coronary arteries using electron microscopic immunocytochemistry. During a hypoxic period of 1 min, coronary vasodilatation was produced in the Langendorff heart preparation and increased levels of substance P and acetylcholine were released into the perfusate. The possibility that these substances are released from endothelial cells during hypoxia and contribute to the hyperaemic response is discussed.  相似文献   
994.
Interleukin-1 (Il-1) was added to collagen lattice cultures of human skin fibroblasts. No cell division was induced, the ability of fibroblasts to contract the lattices was decreased and a dose-related inhibition of collagen synthesis without effect on non-collagen proteins was found. Indomethacin had no influence on these effects.  相似文献   
995.
1.INTRODUCTION Manyreal worldsystemscanbemodeledaslinearpa rameter varying(LPV)systems[1],whosestate spacerepresentationmatricesarefunctionsofasetof parametersthataremeasurableinrealtime.Recent ly,manyresearchersathomeandabroadhavebeen engagedinthestabilityanalysisandgainscheduling controlofLPVsystemsextensivelyandagreatnum berofimportantresultshavebeenreportedinthelit erature(see,forinstance,Refs.[1~7]andtheref erencestherein).Mostoftheseresultsfocusoncon tinuous timecases,while…  相似文献   
996.
1 .INTRODUCTIONBP methodis a widely used classical learning algo-rithmof Neural Networks . Whileit has two short-ages ,i .e .slowconvergence rate and existinglocalmini mum of the cost function. Many new algo-rithms such as modification methods of BP meth-od, conjugate gradient methods , RLS methods ,quasi-Newton methods , evolving learning meth-ods ,chaos-learning algorithms have been proposedso far[1 ~7]. However ,these novel algorithms neverdirectly utilize the 2-ed order differentia…  相似文献   
997.
Co-integration analysis is used in a study of the advertising and sales relationship using the Lydia Pinkham data set. The series are shown to have a valid long-run relationship while Granger-causality runs in both directions. The latter is found by using a causality test involving the co-integration restrictions which seem to constitute a crucial part of such tests in the case of co-integrated variables. A comparison with previous models shows that forecasting co-integrated series is more accurate with error-correction systems, especially in the case of multi-step forecasting.  相似文献   
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