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  • Polymer and Materials Science  (3)
  • Velocity storage  (2)
  • 1
    Electronic Resource
    Electronic Resource
    The influence of head position and head reorientation on the axis of eye rotation and the vestibular time constant during postrotatory nystagmus (1992)
    Springer
    Experimental brain research 91 (1992), S. 121-128 
    Details
    ISSN: 1432-1106
    Keywords: Vestibuloocular reflex ; Velocity storage ; Active head tilt ; Semicircular canals ; Otolith ; Human
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary Reorienting the head with respect to gravity during the postrotatory period alters the time course of postrotatory nystagmus (PRN), hastening its decline and thereby reducing the calculated vestibular time constant. One explanation for this phenomenon is that the head reorientation results in a corresponding reorientation of the axis of eye rotation with respect to head coordinates. This possibility was investigated in 10 human subjects whose eye movements were monitored with a three-dimensional magnetic field — search — coil technique using a variety of head reorientation paradigms in a randomized order during PRN following the termination of a 90°/s rotation about earth vertical. Average eye velocities were calculated over two time intervals: from 1 s to 2 s and from 7 s to 8 s after cessation of head rotation. The time constant was estimated as one third of the duration of PRN. For most conditions, a reorientation of the head with respect to gravity 2 s after the rotation had stopped did not significantly alter the direction of the eye velocity vector of PRN with respect to head coordinates. This strongly indicates that, in humans, PRN is mainly stabilized in head coordinates and not in space coordinates, even if the otolith input changes. This finding invalidates the notion that the shortening of PRN due to reorientation of the head could be due to a change of the eye velocity vector towards a direction (torsion), which is not detectable with the eye recording methods (electrooculography) used in earlier studies. The results regarding the vestibular time constant basically confirm earlier findings, showing a strong dependence on static head position, with the time constant being lowest if mainly the vertical canals are stimulated (60° nose up and 90° left ear down). In addition, the time constant was drastically shortened for tilts away from upright. The reduction in vestibular time constant with head reorientation cannot be explained solely on the basis of the dependence of the time constant on static head position. A clear example is provided by head reorientations back towards the upright position, which results in a decrease in the time constant, rather than an increase that would be expected on the basis of static head position.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00230020
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  • 2
    Electronic Resource
    Electronic Resource
    Otolith-semicircular canal interaction during postrotatory nystagmus in humans (1996)
    Springer
    Experimental brain research 108 (1996), S. 463-472 
    Details
    ISSN: 1432-1106
    Keywords: Vestibulo-ocular reflex ; Velocity storage ; Head reorientation ; Semicircular canals ; Otolith organs ; Human
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract The otolith-semicircular canal interaction during postrotatory nystagmus was studied in ten normal human subjects by applying fast, short-lasting, passive head and body tilts (15, 30, 45, or 90° in the roll or pitch plane) 2 s after sudden stop from a constant-velocity rotation (100°/s) about the earth-vertical axis in yaw. Eye movements were measured with three-dimensional magnetic search coils. Following the head tilt, activity in the semicircular canal primary afferents continues to reflect the postrotatory angular velocity vector in head-centered coordinates, whereas otolith primary afferents signal a different orientation of the head relative to gravity. Despite the change in head orientation relative to gravity, postrotatory eye velocity decayed closely along the axis of semicircular canal stimulation (horizontal in head coordinates) for large head tilts (90°) and also for small head tilts (15–45°) for reorientations in the pitch plane. Only for small head tilts (15–45°) in the roll plane was there a reorientation of the eye rotation axis toward the gravitational vector. This reorientation was approximately compensatory for 15° head tilts. For 30° and 45° head tilts the eye rotation axis tilted toward the gravitational vector by about the same amount as for 15° head tilts. These results suggest that, with the exception of small head tilts in the roll plane, there was no compelling data showing a relationship between the eye rotation axis and head tilt and that postrotatory nystagmus is largely organized in head-centered rather than gravity-centered coordinates in humans. This indicates a rudimentary, nonlinear, and direction-specific interaction of semicircular canal and otolith signals in the central vestibular system in humans.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00227269
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  • 3
    Electronic Resource
    Electronic Resource
    A new method to measure temperatures in polymer melts using heusler alloysDedicated to Prof. H. Janeschitz-Kriegl on the occasion of his 65th birthday. (1989)
    New York, NY [u.a.] : Wiley-Blackwell
    Journal of Applied Polymer Science 38 (1989), S. 1739-1743 
    Details
    ISSN: 0021-8995
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Notes: With the help of ferromagnetic Heusler alloys, which are mixed in powdery form into a cylindrical polymer sample surrounded by an induction coil, temperature can be measured. Some 10 K below the Curie temperature small temperature changes already yield considerable signals in the induction coil via the temperature dependence of the permeability of the alloy. From the tremendous variety of Heusler alloys avaialable for each temperature region of interest the proper material can be chosen. The amount of sample needed is small enough to leave the rheological properties of the melt unchanged. Measurements do not involve touching the sample and follow each temperature change more or less simultaneously since the grains of the alloys are very small and have very small heat capacities only.
    Additional Material: 3 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/app.1989.070380912
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  • 4
    Electronic Resource
    Electronic Resource
    A new inductive detection for the magnetoviscometer (1989)
    New York, NY [u.a.] : Wiley-Blackwell
    Journal of Applied Polymer Science 37 (1989), S. 2675-2682 
    Details
    ISSN: 0021-8995
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Notes: For a new magnetoviscometer with an inhomogeneous magnetic field to move iron spheres similar to the Stokes experiment, a nonoptical detection was developed. As a measuring principle the change of the impedance of a coil, penetrated by the sphere is used. The measuring principle is the change of impedance of an induction coil wrapped around the cell by the sphere. The measuring block, consisting of heating elements, detection coils, and a measuring cell is quite simple and therefore well suited for measuring under pressure. Since the proper cells are simply brass cylinders closed by a screw, they can be thrown away after the experiment (e.g., for network-building polymers). Examples for said measurements are given.
    Additional Material: 8 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/app.1989.070370918
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  • 5
    Electronic Resource
    Electronic Resource
    Der Blasensäulenfermenter für die Massensuspensionskultur tierischer ZellenErweiterte Fassung eines Vortrages auf der Dechema-Jahrestagung am 24. Juni 1977 in Frankfurt/M. (1978)
    Weinheim : Wiley-Blackwell
    Chemie Ingenieur Technik - CIT 50 (1978), S. 472-473 
    Details
    ISSN: 0009-286X
    Keywords: Massensuspensionskultur ; tierische Zellen ; Blasensäule ; Schlaufenreaktor ; Fließbild ; Begasungsleistung ; Scale up ; Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Process Engineering, Biotechnology, Nutrition Technology
    Additional Material: 1 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cite.330500620
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