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  • 1995-1999  (265)
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  • 1
    Unknown
    New York : Springer
    Call number: B080:189
    Keywords: Physiology / Mathematics
    Pages: viii, 766 p. : ill.
    ISBN: 0387983813
    Signatur Availability
    B080:189 departmental collection or stack – please contact the library
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  • 2
    Electronic Resource
    Electronic Resource
    Boston, USA and Oxford, UK : Blackwell Publishers Inc
    Computational intelligence 14 (1998), S. 0 
    ISSN: 1467-8640
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Computer Science
    Notes: We investigate a formal representation of time units, calendars, and time unit instances as restricted temporal entities for reasoning about repeated events. We generalize Allen's interval relations to a class level, and based on interval classes we define time units. We examine characteristics of time units, and provide a categorization of the hierarchical relations among them. Hence we define an abstract hierarchical unit structure (a calendar structure) that expresses specific relations and properties among the units that compose it. Specific objects in the time line are represented based on this formalism, including nonconvex intervals corresponding to repeated events. A goal of this research is to be able to represent and reason efficiently about repetition in time.
    Type of Medium: Electronic Resource
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  • 3
    ISSN: 1432-119X
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Abstract  Amelogenins are the most abundant constituent in the enamel matrix of developing teeth. Recent investigations of rodent incisors and molar tooth germs revealed that amelogenins are expressed not only in secretory ameloblasts but also in maturation ameloblasts, although in relatively low levels. In this study, we investigated expression of amelogenin in the maturation stage of porcine tooth germs by in situ hybridization and immunocytochemistry. Amelogenin mRNA was intensely expressed in ameloblasts from the differentiation to the transition stages, but was not detected in maturation stage ameloblasts. C-terminal specific anti-amelogenin antiserum, which only reacts with nascent amelogenin molecules, stained ameloblasts from the differentiation to the transition stages. This antiserum also stained the surface layer of immature enamel at the same stages. At the maturation stage, no immunoreactivity was found within the ameloblasts or the immature enamel. These results indicate that, in porcine tooth germs, maturation ameloblasts do not express amelogenins, suggesting that newly secreted enamel matrix proteins from the maturation ameloblast are not essential to enamel maturation occurring at the maturation stage.
    Type of Medium: Electronic Resource
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  • 4
    ISSN: 1432-119X
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Abstract  The presence of NADPH diaphorase staining was compared with the immunohistochemical localization of four NADPH-dependent enzymes – neuronal (type I), inducible (type II), and endothelial (type III) nitric oxide synthase (NOS) and cytochrome P450 reductase. Cell types that were immunoreactive for the NADPH-dependent enzymes were also stained for NADPH diaphorase, suggesting that endothelial and neuronal NOS and cytochrome P450 reductase all show NADPH diaphorase activity in formaldehyde-fixed tissue. However, in some tissues, the presence of NADPH diaphorase staining did not coincide with the presence of any of the NADPH-dependent enzymes we examined. In vascular endothelial cells, the punctate pattern of staining observed with NADPH diaphorase histochemistry was identical to that seen following immunohistochemistry using antibodies to endothelial NOS. In enteric and pancreatic neurons and in skeletal muscle, the presence of NADPH diaphorase staining correlated with the presence of neuronal NOS. In the liver, sebaceous glands of the skin, ciliated epithelium, and a subpopulation of the cells in the subserosal glands of the trachea, zona glomerulosa of the adrenal cortex, and epithelial cells of the lacrimal and salivary glands, the presence of NADPH diaphorase staining coincided with the presence of cytochrome P450 reductase immunoreactivity. In epithelial cells of the renal tubules and zona fasciculata and zona reticularis of the adrenal cortex, NADPH diaphorase staining was observed that did not coincide with the presence of any of the enzymes. Inducible NOS was not observed in any tissue. Thus, while tissues that demonstrate immunoreactivity for neuronal and endothelial NOS also stain positively for NADPH diaphorase activity, the presence of NADPH diaphorase staining does not reliably or specifically indicate the presence of one or more NOS isoforms.
    Type of Medium: Electronic Resource
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  • 5
    ISSN: 1432-1203
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Abstract Familial amloidosis, Finnish type (FAP IV) was identified clinically in an American kindred with Scandinavian ancestry. A polymerase chain reaction (PCR)-based DNA diagnostic assay was used to identify a G-to-A mutation at position 654 of the gelsolin cDNA (G654A) in this family. Molecular diagnostic testing demonstrated the mutation in individuals in three generations — the clinically affected proband, her deceased clinically affected father, and her presumably affected presymptomatic child. This report represents a rare example of FAP IV and the G654A mutation identified in a family outside Finland. The disease-associated haplotype was similar to that observed in Finnish FAP IV families (suggesting common distant ancestry).
    Type of Medium: Electronic Resource
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  • 6
    ISSN: 1432-2234
    Keywords: Key words: Energy transfer ; Shell model ; Multipolar interaction ; Angular dependence ; Elpasolite crystal
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Abstract. The interaction between multipoles is not isotropic even in cubic systems. This results in the introduction of geometric reduction factors in the calculation of energy-transfer rates in crystals. We derive these reduction factors for the cases of dipole–dipole, dipole–quadrupole, and quadrupole–quadrupole couplings and present a general procedure for their derivation in other cases. For the dipole–dipole case the geometric factor is independent of the distribution of the acceptor species, but for higher-order couplings, a significant angular dependence is found.
    Type of Medium: Electronic Resource
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  • 7
    ISSN: 1432-2250
    Source: Springer Online Journal Archives 1860-2000
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Notes: Abstract: We consider nonlinear wave motions in strongly buoyant mixed forced–free convection boundary layer flows. In the natural limit of large Reynolds number the nonlinear evolution of a single monochromatic wave mode is shown to be governed by a novel wave/mean-flow interaction in which the wave amplitude and the wave induced mean-flow are of comparable size. A nonlinear integral equation describing the bifurcation to finite-amplitude travelling wave solutions is derived. Solutions of this equation are presented together with a discussion of their physical significance.
    Type of Medium: Electronic Resource
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  • 8
    ISSN: 1432-0452
    Keywords: Key words: Distributed systems – Event abstraction – Causality – Precedence relation – Partial order – Vector time – Logical time
    Source: Springer Online Journal Archives 1860-2000
    Topics: Computer Science
    Notes: Abstract. An important problem in analyzing distributed computations is the amount of information. In event-based models, even for simple applications, the number of events is large and the causal structure is complex. Event abstraction can be used to reduce the apparent complexity of a distributed computation. This paper discusses one important aspect of event abstraction: causality among abstract events. Following Lamport [24], two causality relations are defined on abstract events, called weak and strong precedence. A general theoretical framework based on logical vector time is developed in which several meaningful timestamps for abstract events are derived. These timestamps can be used to efficiently determine causal relationships between arbitrary abstract events. The class of convex abstract events is identified as a subclass of abstract events that is general enough to be widely applicable and restricted enough to simplify timestamping schemes used for characterizing weak precedence. We explain why such a simplification seems not possible for strong precedence.
    Type of Medium: Electronic Resource
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  • 9
    ISSN: 1471-4159
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Medicine
    Notes: Abstract: Sporadic Parkinson's disease is associated with a defect in the activity of complex I of the mitochondrial electron transport chain. This electron transport chain defect is transmitted through mitochondrial DNA, and when expressed in host cells leads to increased oxygen free radical production, increased antioxidant enzyme activities, and increased susceptibility to programmed cell death. Pramipexole, a chemically novel dopamine agonist used for the treatment of Parkinson's disease symptoms, possesses antioxidant activity and is neuroprotective toward substantia nigral dopamine neurons in hypoxic-ischemic and methamphetamine models. We found that pramipexole reduced the levels of oxygen radicals produced by methylpyridinium ion (MPP+) both when incubated with SH-SY5Y cells and when perfused into rat striatum. Pramipexole also exhibited a concentration-dependent inhibition of opening of the mitochondrial transition pore induced by calcium and phosphate or MPP+. These results suggest that pramipexole may be neuroprotective in Parkinson's disease by attenuating intracellular processes such as oxygen radical generation and the mitochondrial transition pore opening, which are associated with programmed cell death.
    Type of Medium: Electronic Resource
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  • 10
    ISSN: 1471-4159
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Medicine
    Notes: Abstract: In vitro studies indicate that p42/p44MAPK phosphorylate both nuclear and cytoplasmic proteins. However, the functional targets of p42/p44MAPK activation in vivo remain unclear. To address this question, we localized activated p42/p44MAPK in hippocampus and cortex and determined their signaling effects after electroconvulsive shock treatment (ECT) in rats. Phosphorylated p42/p44MAPK content increased in the cytoplasm of hippocampal neurons in response to ECT. Consistent with this cytoplasmic localization, inhibition of ECT-induced p42/p44MAPK activation by the extracellular signal-regulated kinase kinase inhibitor PD098059 blocked phosphorylation of the cytoplasmic protein microtubule-associated protein 2c (MAP2c), but failed to inhibit the induction of the nuclear protein c-Fos in response to ECT. In contrast to hippocampal neurons, cortical neurons exhibited an increase in amount of phosphorylated p42/p44MAPK in both the nucleus and cytoplasm after ECT. Accordingly, PD098059 blocked the induction of Fos-like immunoreactivity in the nuclei of cortical neurons as well as MAP2c phosphorylation in the cytoplasm. Our data indicate that both nuclear and cytoplasmic substrates can be activated by p42/p44MAPK in vivo. However, the functional targets of p42/p44MAPK signaling depend on the precise location of p42/p44MAPK within different subcellular compartments of brain regions. These results indicate unique functional pathways of p42/p44MAPK-mediated signal transduction within different brain regions in vivo.
    Type of Medium: Electronic Resource
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