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  • 11
    ISSN: 1432-1106
    Keywords: Cutaneous EPSPs ; Fictive locomotion ; Cat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary We examined modulation of transmission in short-latency, distal hindlimb cutaneous reflex pathways during fictive locomotion in 19 decerebrate cats. Fictive stepping was produced either by electrical stimulation of the mesencephalic locomotor region (MLR) or by administration of Nialamide and 1-DOPA to acutely spinalized animals. Postsynaptic potentials (PSPs) produced by electrical stimulation of low threshold afferents (〈 2.5 times threshold) in the superficial peroneal (SP), sural, saphenous or medial plantar nerves were recorded intracellularly from various extensor (n = 28) and flexor (n = 24) motoneurons and averaged throughout the step cycle, together with voltage responses to intrasomatic constant current pulses (in order to monitor relative cell input resistance). Each motoneuron studied displayed rhythmic background oscillations in membrane potential and correlated variations in input resistance. The average input resistance of extensor motoneurons was lowest during mid-flexion, when the cells were relatively hyperpolarized and silent. Conversely, average input resistance of flexor motoneurons was highest during mid-flexion, when they were depolarized and active. The amplitude of the minimum-latency excitatory components of PSPs produced by cutaneous nerve stimulation were measured from computer averaged records representing six subdivisions of the fictive step cycle. Oligosynaptic EPSP components were consistently modulated only in the superficial peroneal responses in flexor motoneurons, which exhibited enhanced amplitude during the flexion phase. With the other skin nerves tested (sural, saphenous, and plantar), no consistent patterns of modulation were observed during fictive locomotion. We conclude that transmission through some, but not all, oligosynaptic excitatory cutaneous pathways is enhanced by premotoneuronal mechanisms during the flexion phase of fictive stepping in several cat hindlimb motor nuclei. The present results suggest that the patterns of interaction between the locomotor central pattern generator and excitatory cutaneous reflex pathways depend on the source of afferent input and on the identity of the target motoneuron population.
    Type of Medium: Electronic Resource
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  • 12
    Electronic Resource
    Electronic Resource
    Springer
    Communications in mathematical physics 17 (1970), S. 343-347 
    ISSN: 1432-0916
    Source: Springer Online Journal Archives 1860-2000
    Topics: Mathematics , Physics
    Notes: Abstract Recently a certain class of homogeneous world models filled with perfect fluid have been discussed, [1, 2]. The corresponding results when anisotropic stresses are included are now examined.
    Type of Medium: Electronic Resource
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  • 13
    ISSN: 1432-1106
    Keywords: Fictive locomotion ; Cutaneous reflex pathways ; Flexor digitorum longus muscle ; Motoneurons ; Interneurons ; Reflex modulation ; Spinal cord
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary We examined modulation of transmission of short-latency excitation produced by distal hindlimb cutaneous input, as well as fluctuations in motoneuron membrane potential and input resistance, in flexor digitorum longus (FDL) motoneurons during fictive locomotion. Fictive stepping was induced in unaesthetized, decerebrate cats either by repetitive stimulation of the mesencephalic locomotor region (MLR) or by administration of Nialamide and 1 DOPA after low spinal section. In the MLR preparations, brief depolarizing waves occurred in FDL cells during the early flexion phase of fictive stepping, immediately after cessation of activity in extensor muscles. In some FDL cells, plateau-like depolarizations also occurred during the extensor phase. Fictive stepping induced in acutely spinalized cats by administration of l-DOPA was slower and more variable; peak polarization in FDL motoneurons always occurred during the early flexion phase but there was usually no distinct depolarization during extension. In both types of preparation, the initial EPSP components in synaptic potentials (SP-EPSPs) produced by electrical stimulation of the cutaneous division of the superficial peroneal nerve (SP) were maximally facilitated during early flexion, coincident with the peak of background depolarization. This enhancement was manifested by an increase in the amplitude of initial SP-EPSP components or by decreased central latency of the initial EPSP components, or both. In most FDL motoneurons, input resistance decreased systematically during late flexion, coincident with relative membrane hyperpolarization. Correction of SP-EPSP amplitudes for changes in input resistance suggested that SP-EPSP facilitation persisted throughout the flexion phase These findings are discussed with reference to modulation of cutaneous reflexes during locomotion and the possibility that excitatory last-order interneurons in particular cutaneous reflex pathways may distribute excitatory drive from the central pattern generator for locomotion to FDL α-motoneurons
    Type of Medium: Electronic Resource
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  • 14
    Electronic Resource
    Electronic Resource
    Springer
    Cellular and molecular life sciences 27 (1971), S. 1090-1091 
    ISSN: 1420-9071
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary In accordance with the mustard-oil-containing families of the Capparidales ‘Myrosinase’ can be detected inBatis maritima. This observation suggests a relationship between Batidaceae and Capparidales also indicated by some morphological and anatomical data.
    Type of Medium: Electronic Resource
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  • 15
    Electronic Resource
    Electronic Resource
    Springer
    Monatshefte für Chemie 102 (1971), S. 627-634 
    ISSN: 1434-4475
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Zusammenfassung Die Acylierung von 2-Amino-3.3-diphenyl-5-methyl-1-pyrrolin (1) und 2-Amino-3.3-diphenyl-1-pyrrolin (2) erfolgt in den hier untersuchten Fällen am N-2-(exo)-Stickstoff. Die Umsetzung der cyclischen Amidine1 und2 mit BrCN gibt jedoch neben den N-2-(exo)-auch die N-1-(endo)-Cyanamidine. Diese werden in die entsprechenden Carbamoyl- und Thiocarbamoylamidine umgewandelt.
    Notes: Abstract Acylations of 2-amino-3.3-diphenyl-5-methyl-1-pyrroline (1) and 2-amino-3.3-diphenyl-1-pyrroline (2) occur at the N-2-(exo)-nitrogen. However, reaction of1 and2 with BrCN yields not only the N-2-(exo)-cyanoamidines but also the N-1-(endo)-isomers. Either is converted into the corresponding carbamoyl and thiocarbamoyl amidines.
    Type of Medium: Electronic Resource
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  • 16
    Electronic Resource
    Electronic Resource
    Springer
    Monatshefte für Chemie 102 (1971), S. 635-642 
    ISSN: 1434-4475
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Zusammenfassung Aus 2-Amino-1-pyrrolinen können durch bekannte Reaktionen stabile Carbamidinoderivate dargestellt werden. Die Addition von Bisbenzhydrylcarbodiimid an 2-Amino-1-pyrroline, gefolgt von saurer Abspaltung der Benzhydrylreste, stellt eine neue vorteilhafte Methode zur Herstellung der nor-Derivate dieser Verbindungsklasse (Tab. 2) vor. Einheitliche N2-Alkyl-und Arylsulfonylderivate dieser Reihe erhält man mit den 1-(N2-Sulfonylcarbamidino)-3.5-dimethylpyrazolen.
    Notes: Abstract Stable carbamidine derivatives of 2-amino-1-pyrrolines have been prepared using known reactions. The addition of bis-benzhydrylcarbodiimide to 2-amino-1-pyrrolines followed by acid cleavage of the benzhydryl moieties provides an improved method for the preparation of nor-derivatives of this class of compounds (Table 2). N2-Alkyl-and arylsulfonyl derivatives of this series have been selectively obtained from 1_(N2-sulfonylcarbamidino)-3.5-dimethylpyrazoles.
    Type of Medium: Electronic Resource
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  • 17
    Electronic Resource
    Electronic Resource
    Springer
    European journal of nutrition 10 (1970), S. 111-114 
    ISSN: 1436-6215
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition , Medicine
    Description / Table of Contents: Summary 1. In aqueous phosphate buffer diacetyl tartaric acid monoglyceride is hydrolyzed to glyceride and tartaric acid. 2. Orally administered14C-labeled emulsifier to rats is absorbed to 26–31% of the activity given. 3. 21–20% are oxidized to14CO2, 8–13% are excreted in the urine, 2% are retained in the carcass.
    Notes: Zusammenfassung 1. Die vorliegende Substanz wird in geringem Umfang, maximal zu 10–20%, im wäßrigen Medium gespalten. 2. Im Organismus der Ratte wird rd. 1/3 der14C-Aktivität der Substanz resorbiert. 3. Die Ausscheidung der14C-Aktivität erfolgt zu 12–20% via Lunge, zu 8–13 % via Niere, während der im Körper verbleibende Anteil nur 2% ausmacht.
    Type of Medium: Electronic Resource
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  • 18
    Electronic Resource
    Electronic Resource
    Springer
    European journal of nutrition 13 (1974), S. 143-144 
    ISSN: 1436-6215
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition , Medicine
    Type of Medium: Electronic Resource
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  • 19
    ISSN: 1436-6304
    Source: Springer Online Journal Archives 1860-2000
    Topics: Mathematics , Economics
    Type of Medium: Electronic Resource
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  • 20
    Electronic Resource
    Electronic Resource
    Springer
    OR spectrum 11 (1989), S. 191-195 
    ISSN: 1436-6304
    Source: Springer Online Journal Archives 1860-2000
    Topics: Mathematics , Economics
    Description / Table of Contents: Summary The technique of designing and constructing simulation models is difficult and requires a lot of knowledge and experience. In general, users of simulation models don't have this expert knowledge. Up to now, it has not been possible to incorporate the expert knowledge necessary for the overall modelling within an expert system which would then in turn make the techniques accessible to the inexperienced user. In general, the close cooperation among experts in the fields of application and simulation techniques remains — for the time being — the only guarantee for successfully scrutinizing a model study. It is, however, possible to combine expert systems and simulation models when using carefully chosen, closely defined fields of application. It is here that an important area of interest and study lies. There are three conceivable alternatives: 1. To provide a simulation model with an intelligent environment which supports the user in constructing as well as evaluating the results made. 2. An expert system contains a simulation model as a possible component. If the expert system needs information that is not directly available, a simulation model is accessed which in turn sends the necessary data back to the expert system. 3. A simulation model contains an expert system as a component. In this case, the model has specific strategies at its disposal that are to be taken into consideration. If the model reaches a point where decisions have to be made, the simulation model turns to the expert system in order to receive information on relevant decisions. These relevant decisions are then used to determine the further course of the model. All three alternatives assume that the expert system as well as the simulation system have an open architecture. The open architecture is a prerequisite for the possibility of coupling the two. Up to now, this requirement has rarely been achieved.
    Notes: Zusammenfassung Der Entwurf und der Aufbau von Simulationsmodellen ist eine schwierige Technik, die sehr viel Wissen und Erfahrung voraussetzt. Die Anwender von Simulationsmodellen verfügen in der Regel über dieses Expertenwissen nicht. Bisher ist es nicht möglich, das für die Modellierung insgesamt erforderliche Expertenwissen in ein Expertensystem zu inkorporieren um es auf diese Weise dem in der Simulationstechnik unerfahrenen Anwender zugänglich zu machen. Im allgemeinen bleibt die enge Zusammenarbeit zwischen Fachleuten auf dem Anwendungsgebiet und der Simulationstechnik bis auf weiteres die einzige Garantie für eine erfolgreiche Modelluntersuchung. In ausgewählten, sehr engen abgegrenzten Anwendungsgebieten ist es jedoch möglich, Expertensysteme und Simulationsmodelle zu vereinen. Hier entwickelt sich ein bedeutendes Arbeits- und Aufgabenfeld. Es sind drei Alternativen vorstellbar: 1. Ein Simulationsmodell erhält eine intelligente Umgebung, die den Anwender beim Modellaufbau und bei der Ergebnisauswertung unterstützt. 2. Ein Expertensystem enthält als eine mögliche Komponente ein Simulationsmodell. Falls das Expertensystem Informationen benötigt, die nicht direkt verfügbar sind, wird ein Simulationsmodell angestoßen, das die erforderlichen Daten an das Expertensystem zurückliefert. 3. Ein Simulationsmodell enthält als Komponente ein Expertensystem. In diesem Fall enthält das Modell Strategien, die zu berücksichtigen sind. Falls das Modell an einen Punkt kommt, an dem Entscheidungen getroffen werden müssen, wendet sich das Simulationsmodell an das Expertensystem und läßt sich die maßgebenden, den weiteren Modellablauf bestimmenden Entscheidungen mitteilen. Alle drei Alternativen verlangen vom Expertensystem und dem Simulationssystem eine offene Architektur. Die offene Architektur ist Voraussetzung dafür, daß sich beide Systeme koppeln lassen. Diese Forderung ist bisher kaum erfüllt.
    Type of Medium: Electronic Resource
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