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  • 1
    Electronic Resource
    Electronic Resource
    Springer
    Biological cybernetics 67 (1992), S. 369-375 
    ISSN: 1432-0770
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Computer Science , Physics
    Notes: Abstract Each leg of a standing stick insect acts as a height controller. The leg contains several joints. Most of these joints are known to be controlled by feedback loops which are the basis of resistance reflexes (review Bässler 1983). This leads to the question of whether the resistance reflex of the whole leg can be understood as a simple, vectorial sum of the individual reflexes provided by the different joints, or whether additional properties emerge by simultaneous stimulation of several joints. Force measurements were performed while passively moving the middle leg tarsus of a fixed stick insect (Carausius morosus) stepwise to different positions. From the dynamic and static forces the torques developed by each joint were calculated. They were compared with the torques developed when only a single joint was moved by the same amount. The comparison shows that for a large range of positions there are no differences between both situations. Differences occur in two cases. First, the muscle system controlling the coxa-trochanter joint seems to be more strongly excited when the entire leg is moved than when only the one joint is moved. This change increases the linearity of the whole system for small deviations from the zero position. Second, the torque developed by the extensor tibiae system for negative steps (corresponding to increased body height), and the levator of coxa and trochanter for positive steps, decreases rather than increases when the whole leg is moved to extreme positions. This contributes to a decrease in the slope of the force-height characteristic and thus to a more non-linear behaviour of the whole system for the extreme positions. It is well known that the amplification factors of resistance reflexes in the leg show a large variation (Bässler 1972a; Kittmann 1991). Our results indicate that any change of the amplification factor influences the reflexes in all leg joints in the same way.
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  • 2
    Electronic Resource
    Electronic Resource
    Springer
    Archives of dermatological research 201 (1955), S. 266-276 
    ISSN: 1432-069X
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Zusammenfassung Eine Patientin mit schwerer Dermatomyositis, Bronchopneumonie, Anämie, Leukopenie, mit stark pathologischen Leberfunktionen, Gesamteiweiß und Eiweißfraktionen kam unter Terramycin klinisch zur Abheilung.
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  • 3
    Electronic Resource
    Electronic Resource
    Springer
    Archives of dermatological research 213 (1961), S. 270-274 
    ISSN: 1432-069X
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Type of Medium: Electronic Resource
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  • 4
    ISSN: 1432-069X
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
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  • 5
    Electronic Resource
    Electronic Resource
    Springer
    Monatshefte für Chemie 82 (1951), S. 702-707 
    ISSN: 1434-4475
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Zusammenfassung Die einzelnen Darstellungsmöglichkeiten für Tetradeuterothiophen wurden überprüft. Die Darstellung wurde schließlich durch wiederholten Wasserstoffaustausch zwischen Thiophen und 69% iger schwerer Schwefelsäure ausgeführt. Das Austauschgleichgewicht wurde anfänglich bei Zimmertemperatur und einer Schütteldauer von 100 Stdn., später bei 40° C und 30stündiger Schütteldauer nahezu erreicht. Es wurde auch die Darstellung von partiell deuterierten Thiophenen durchgeführt, doch konnten keine homogenen Reaktionsprodukte erhalten werden. So enthält z. B. ein Präparat mit einem Deuteriumgehalt entsprechend dem Dideuterothiophen auch Mono- und Trideuterothiophen.
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  • 6
    ISSN: 1434-4475
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
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  • 7
    Electronic Resource
    Electronic Resource
    Springer
    Monatshefte für Chemie 82 (1951), S. 748-751 
    ISSN: 1434-4475
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Zusammenfassung Es werden die Diffusionskonstanten von110Ag in Kupfer bei 460, 500, 550 und 600° C mitgeteilt. Zur Anwendung gelangte die Kontaktmethode, bei der eine radioaktive Silbertablette110Ag auf eine inaktive Kupfertablette mit ebene polierten Oberflächen gepreßt und auf Diffusionstemperatur gebracht wurde. Nach beendigter Diffusion wird die inaktive Kupfertablette abgehoben und die Aktivität des eindiffundierten110Ag in einer Zählrohrapparatur gemessen. Die Ergebnisse erfüllen dieArrheniussche Beziehung und es errechnet sich die Aktivierungsenergie für den Diffusionsvorgang Silber in Kupfer zu 94800 cal. Unser weiteres Interesse gilt der gleichen Größe bei Sinterkörpern des gleichen Systems, jedoch mit porösen Komponenten (Sinterkörpern) in Abhängigkeit von deren Vorgeschichte, des Porenvolumens und der Form und Verteilung der Poren.
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  • 8
    Electronic Resource
    Electronic Resource
    [s.l.] : Nature Publishing Group
    Nature 190 (1961), S. 1110-1112 
    ISSN: 1476-4687
    Source: Nature Archives 1869 - 2009
    Topics: Biology , Chemistry and Pharmacology , Medicine , Natural Sciences in General , Physics
    Notes: [Auszug] We discovered a new example of this 'polymer effect' while studying the metabolism of inorganic nitrogen. It was observed that the enzymic activity of nitrate reductase preparations obtained from the mould Neurospora crassa (5297J.) and purified by ammonium sulphate fractionation and column ...
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  • 9
    Electronic Resource
    Electronic Resource
    Springer
    International journal of biometeorology 11 (1967), S. 301-310 
    ISSN: 1432-1254
    Source: Springer Online Journal Archives 1860-2000
    Topics: Geography , Physics
    Description / Table of Contents: Zusammenfassung Ein flexibles mathematisches Verfahren zur Überwachung der Dekompression bei Tauchern wurde entwickelt, durch Modifikation des klassischen Modells von Haldane für den Transport träger Gase.Es beruht auf der Annahme,dass träge Gase so lange in den Geweben eines Tauchers in Lösung bleiben, als eine bestimmte metastabile Grenze nicht überschritten wird. Diese Grenze ändert sich mit der Tiefe,der Natur des trägen Gases und der spezifischen Zeitkonstante seines Transports im Körper. Die vorgeschlagenen metastabilen Grenzen (M-Werte) des Partialdruckes von gelöstem Helium wurden empirisch entwickelt in der Experimental Diving Unit der Marine der Vereinigten Staaten.Diese Grenzen erlauben die Erfassung der Dekompressionsvorgänge durch Digital Computer und es wird angenommen, dass sie sicherer sind als die gebräuchlichen Dekompressions-Tabellen für langes Tieftauchen.
    Abstract: Resume On a établi un procédé mathématique fléxible pour suivre les phénomènes de décompression chez les plongeurs.Pour ce faire, on a modifié le modèle classique de Haldane concernant le transport d'un gaz inerte. Comme base, on admet que les gaz inertes resteront en solution dans les tissues des plongeurs aussi longtemps qu'une limite métastatique n'est pas franchie.Cette limite varie avec la profondeur,la nature du gaz inerte et la constante de temps spécifique de son transport dans le corps. Les limites métastatiques proposées (valeurs-M)de la pression partielle de l'hélium dissous ont été déterminées empiriquement à l' "Expérimental Diving Unit"de la marine des Etats-Unis. Ces limites permettent de calculer les processus de décompression au moyen d'ordinateurs.On admet en outre que ce procédé est plus sûr que les tables de décompression usuelles, surtout dans le cas de plongées profondes et de longue durée.
    Notes: Abstract A flexible mathematical treatment of diver decompression has been developed by modifying the classical Haldanian model of inert gas transport. It is based on the assumption that inert gases will remain in solution in the tissues of a diver as long as a particular metastable limit is not exceeded,and that this limit varies with depth, nature of the inert gas,and the specific time constant of its transport in the body. Proposed metastable limits (M-values)of dissolved helium partial pressure have been developed empirically by the Experimental Diving Unit of the United States Navy. These limits permit the design by digital computer of decompression procedures expected to be safer than contemporary decompression tables for extended deep dives.
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  • 10
    ISSN: 1573-0875
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Geosciences
    Notes: Conclusions The results of our experiments in the light of other available experimental evidence lead us to the following conclusions: (1) The metabolic acceleration in a helium atmosphere is due primarily to the thermal properties of that gas, mediated to some extent by increases in spontaneous activity. Helium may cause a transient decrease in red cell indexes, and this too is likely to be due to the thermal stress. (2) Oxygen consumption is slightly reduced on exposure to a low pressure, pure oxygen atmosphere that provides a normal alveolar oxygen tension. This effect is intimately interrelated with changes in evaporative water loss and activity and may be caused by the thermodynamic properties of this gaseous environment. (3) A neon-oxygen atmosphere shows no immediately obvious biological hazard for exposures of up to one week, and along with helium this gas appears to offer some protective advantage in altitude decompression. A suitable neon-oxygen atmosphere at half an atmosphere total pressure would have thermal properties akin to air and experimentally seems indeed to possess some of the theoretical advantages proposed for it (Bond, 1963; Roth, 1966). (4) The question of whether light inert gases such as helium and nitrogen exert molecular effects at atmospheric and subatmospheric pressures is still unresolved as is the enigma of an absolute ‘metabolic’ requirement of mammals for gaseous nitrogen.
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