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  • 1995-1999  (1)
  • 1955-1959  (2)
  • Polymer and Materials Science  (2)
  • Larynx  (1)
  • 1
    ISSN: 1432-2102
    Keywords: Schlüsselwörter Multidetektor ; CT ; MSCT ; Larynx ; Tumoren ; Multiplanare Rekonstruktion ; Key words Computer tomography ; Larynx Head and neck tumors
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Description / Table of Contents: Summary The purpose of the study was to preoperatively investigate small laryngeal carcinomas using multi-slice spiral CT (MSCT) and subsequent multiplanar reconstructions (MPR) and to compare the results to the detailed spread found at surgery and histology. Nine patients with small (T1, T2) laryngeal cancer were investigated on a MSCT scanner (Siemens plus 4 Volume Zoom, Siemens). A 4×1 mm collimation, 120 kV, 200 mAs and a 0.5 seconds rotation time were used, allowing a coverage of the entire larynx in approximately 10 seconds within a single breathhold. Multiplanar reconstruction’s (MPR) in sagittal and coronal plane were reconstructed in all patients and rated in consensus reading. In 8 of nine patients, the glottic spread was detected by MSCT, in one cause of a supraglottic tumor a glottic invasion was excluded. The infiltration of the anterior commissure, the infiltration into the subglottic space and the extension into the hypopharynx was correctly assessed in all patients. MSCT was not able to predict infiltration of the arythnoids in two patients. The use of multi-slice spiral CT for the preoperative assessment of small laryngeal tumors shows great promise. The detection or exclusion of subtle spread of these tumors into the supra- or subglottic space and along the glottic level was possible with high accuracy. As the examination time is short, artifacts are rare and multiplanar reconstructions gain in clinical importance.
    Notes: Zusammenfassung Zielsetzung war, kleine Larynxkarzinome mit der Mehrschicht-Spiral-CT (MSCT) und nachfolgenden multiplanaren Rekonstruktionen (MPR) präoperativ zu untersuchen. 9 Patienten mit histologisch gesichertem Larynxkarzinom der Stadien T1 und T2 wurden untersucht. Alle Untersuchungen wurden an einem Mehrschicht-Spiral-CT (Somatom Plus 4 Volume Zoom, Siemens, Forchheim) durchgeführt. Die Abtastung erfolgte mit 4×1 mm Kollimation, 120 kV, 200 mAs bei einer Rotationszeit der Röhre von 0,5 s. Die Beurteilung einer Infiltration erfolgte durch die Bewertung aller drei Ebenen. Das glottische Wachstum entlang der Stimmlippen konnte in 8 von 9 Patienten richtig-positiv nachgewiesen werden. In einem Fall eines supraglottischen Tumors konnte eine glottische Infiltration ausgeschlossen werden. Die Infiltration der vorderen Kommissur, die Infiltration in den subglottischen Raum und die Ausdehnung in den Hypopharynx konnte ebenfalls sicher nachgewiesen bzw. ausgeschlossen werden. Die Infiltration der Aryknorpel konnte in 7 von 9 Fällen korrekt durch die MSCT vorhergesagt werden. Der Einsatz der Mehrschicht-Spiral-CT bei kleinen Larynxkarzinomen zeigt eine hohe Genauigkeit zum Nachweis bzw. zum Ausschluß von Infiltrationen sowohl in der glottischen Ebene, wie auch in den supra- oder subglottischen Raum. Bedingt durch die kurze Untersuchungszeit sind Bewegungsartefakte selten. Multiplanare Rekonstruktionen (MPR) sind klinisch sehr wertvoll.
    Type of Medium: Electronic Resource
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  • 2
    ISSN: 0022-3832
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: Theoretical treatment had shown that syndiotactic propagation should be slightly favored energetically over isotactic propagation in free radical vinyl chloride polymerization. This prediction has been confirmed experimentally by x-ray and infrared investigations of vinyl chloride polymers prepared at various temperatures. The initiator was a peroxide, azodiisobutyronitrile, or tri-n-butylboron, and had no detectable influence on the x-ray and infrared results. As the polymerization temperature is lowered, the number of lines or arcs in the x-ray diffraction pattern and their sharpness gradually increase as a result of the increased crystallinity arising from improved regularity. The regular sequences are indicated to have the syndiotactic configuration from the chain repeat distance. The change in the infrared absorbance ratio of two carbon-chlorine stretching bands with polymerization temperature can be interpreted in agreement with increasing syndiotacticity at decreasing temperature. With the use of simplifying assumptions, the activation energy difference between isotactic and syndiotactic propagation is estimated to be of the order of one-half kcal/mole. The stereoregulated free radical polymerization of vinyl chloride is thus qualitatively similar to that disclosed for other monomers.
    Additional Material: 7 Ill.
    Type of Medium: Electronic Resource
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  • 3
    Electronic Resource
    Electronic Resource
    Hoboken, NJ : Wiley-Blackwell
    Journal of Polymer Science 33 (1958), S. 503-504 
    ISSN: 0022-3832
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Additional Material: 2 Tab.
    Type of Medium: Electronic Resource
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