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  • 1
    Electronic Resource
    Electronic Resource
    [S.l.] : American Institute of Physics (AIP)
    Journal of Applied Physics 88 (2000), S. 2843-2852 
    ISSN: 1089-7550
    Source: AIP Digital Archive
    Topics: Physics
    Notes: Measurements of the spectral and intensity dependences of the optically-induced reversal of current collapse in a GaN metal-semiconductor field-effect transistor (MESFET) have been compared to calculated results. The model assumes a net transfer of charge from the conducting channel to trapping states in the high-resistivity region of the device. The reversal, a light-induced increase in the trap-limited drain current, results from the photoionization of trapped carriers and their return to the channel under the influence of the built-in electric field associated with the trapped charge distribution. For a MESFET in which two distinct trapping centers have been spectrally resolved, the experimentally measured dependence upon light intensity was fitted using this model. The two traps were found to have very different photoionization cross-sections but comparable concentrations (4×1011 cm−2 and 6×1011 cm−2), suggesting that both traps contribute comparably to the observed current collapse.
    Type of Medium: Electronic Resource
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  • 2
    ISSN: 1433-0385
    Keywords: Keywords: IRM ; Surgery of the thyroid gland ; Surface electrode ; Routine monitoring. ; Schlüsselwörter: IRM ; Schilddrüsenchirurgie ; Oberflächenelektrode ; Routinemonitoring.
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Description / Table of Contents: Zusammenfassung. In den letzten Jahren haben sich im wesentlichen 2 unterschiedliche Verfahren des Recurrensmonitorings durchgesetzt: Zum einen die Ableitung von spontanen bzw. evozierten Potentialen mit Hilfe von endoskopisch applizierten Stichelektroden, die in die Kehlkopfadduktoren gestochen werden, zum anderen die zunehmende Verwendung nicht-invasiver Elektroden. Letztere können entweder in Form spezieller Tuben mit integrierten Elektroden oder, wie im Fall der Postcricoidelektrode, in Form von getrennt zum Tubus in die Rachenhinterwand einzubringender Elektroden Anwendung finden. Eine neue Möglichkeit stellt die, von uns in dieser Arbeit beschriebene, an den Tubus anzuklebende Oberflächenelektrode dar. Während der Untersuchungsperiode mit dem intraoperativen Recurrens Monitoring (IRM) betrug bei allen Operationen und Indikationen die Häufigkeit permanenter Paresen 1/174 (0,6 %). Den Vorteil des IRM sehen wir im wesentlichen auch in der schnelleren und sicheren Erkennung des N. laryngeus recurrens; das intraoperative Recurrensmonitoring kann und soll eine schonende und sichere Operationstechnik nicht ersetzen. Wir schlußfolgern, daß das intraoperative Recurrensmonitoring mit Hilfe einer Oberflächenelektrode, die am Tubus festgeklebt wird, eine sichere, zuverlässige und wenig invasive Methode ist, um intraoperativ den N. recurrens zu überwachen.
    Notes: Abstract. In recent years, two methods of intraoperative monitoring of the laryngeal nerve have mostly been used: evoked electromyographic responses via endscopically applied needle electrodes inserted into the adducting laryngeal muscles, and non-invasive electrodes like special tubes with integrated electrodes or separately insertable electrodes like the postcricoid electrode or disposable electrodes attached to the tube, as used in this study. The incidence of recurrent nerve paresis or paralysis during the IRM period was 1/174 nerves (0.6 %). The advantage of the IRM is the quick and certain identification of the nerve; intraoperative monitoring cannot replace a proper surgical technique. We conclude that the IRM, using a laryngeal surface electrode attached to the tube, is a safe and reliable method.
    Type of Medium: Electronic Resource
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  • 3
    ISSN: 1128-045X
    Keywords: Key words Mesorectal vascular pattern ; Stain marking ; Specimen angiography ; Total mesorectal excision
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract The relation between the mesorectal vessels and the mesorectal fascia needs to be clarified, as a total mesorectal excision (TME) probably derives its advantage from the fact that the visceral or mesorectal fascia can be regarded as a “tumor-tight packaging” and does not contain anatomically preformed perforations. The purpose of this investigation was to study both rectal arterial supply and vascular distribution pattern within the mesorectum. The arterial supply to the rectum was studied with the injection technique in 12 porcine and 28 human TME specimens. We stain-marked 12 porcine and 15 human specimens. Thirteen human specimens were angiographed after filling their arterial bed with a radio-opaque substance. The superior rectal artery is the main rectal artery. Terminal branches extend downwards and forward around the rectum to the level of the levator and muscle. The superior rectal artery and vein were found to be enclosed in a fibrous sheath. The main mesorectal vessels do not penetrate the mesorectal fascia. This study supports the hypothesis of bilateral somatic and one central visceral compartment in the pelvis and implies the absolute necessity of tumor removal within an intact mesorectal fascia.
    Type of Medium: Electronic Resource
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