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  • 1
    Electronic Resource
    Electronic Resource
    Springer
    European archives of oto-rhino-laryngology and head & neck 250 (1993), S. 362-365 
    ISSN: 1434-4726
    Keywords: Auditory maturation ; Conductive hearing loss ; Auditory brainstem responses ; Middle latency responses ; Guinea pigs
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary A reversible conductive hearing loss produced during the first 4 weeks post partum caused marked alterations in the development of click-evoked auditory brainstem (ABR) and middle latency (MLR) responses in guinea pigs. The early component PI in the ABR in controls showed adult-like latencies at the time of birth, while the later ABR components PIII and PV and all components investigated in the MLR showed postnatal development characterized by a shortened latency that persisted for the whole period of investigation. The course of the ABR latencies showed the sharpest decrease during the first 2–3 weeks of life, while that for the MLR took place during the first 5 weeks. In addition to the increased ABR thresholds and lengthened ABR latencies due to the conductive hearing loss, development of the ABR inter-peak latencies (IPL) and MLR latencies was retarded. The IPL reached control values 1 week after the end of the deprivation phase, while the delay in MLR started later (4th week) and lasted longer than did that in the ABR. These findings showed that a long-lasting postnatal conductive hearing loss does not generate sustained impairment at the level of the brainstem but can evoke longer-lasting deficiencies at higher stations of the auditory pathway.
    Type of Medium: Electronic Resource
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  • 2
    Electronic Resource
    Electronic Resource
    New York, NY [u.a.] : Wiley-Blackwell
    Biotechnology and Bioengineering 7 (1965), S. 555-558 
    ISSN: 0006-3592
    Keywords: Chemistry ; Biochemistry and Biotechnology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Process Engineering, Biotechnology, Nutrition Technology
    Additional Material: 2 Ill.
    Type of Medium: Electronic Resource
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  • 3
    Electronic Resource
    Electronic Resource
    Springer
    European archives of oto-rhino-laryngology and head & neck 249 (1992), S. 325-328 
    ISSN: 1434-4726
    Keywords: Auditory maturation ; Binaural interaction components ; Auditory brainstem responses ; Conductive hearing loss ; Guinea pigs
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary Reversible conductive hearing loss created during the first 4 weeks post partum caused marked alterations in the maturation of binaural interaction components in the auditory brainstem responses of guinea pigs. In untreated control animals all three components investigated demonstrated postnatal development in terms of latency shortening that was completed during the first 3 weeks of life. Plugging of both external ear canals caused a significant delay in the maturation of the late component DN2, where latency values of the controls were reached only 2 weeks after the end of the treatment, i.e. after 6 weeks of life. Monaural deprivation likewise led to a retarded development of peak latencies during the phase of imbalanced sensory imput. After the end of the one-sided conductive hearing loss the maturation process was markedly enhanced, even resulting in latency values for DN2 and DP1 that were significantly shorter than those of the controls. This phenomenon persisted until the end of the study period and was the case for both plugged and untreated ears in this group of animals. The time course of latencies in two other groups of experimental animals which were deprived in the same way as adults suggests that the effects observed are due to a sensitive period in the maturation process of the auditory pathway.
    Type of Medium: Electronic Resource
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  • 4
    Electronic Resource
    Electronic Resource
    Weinheim : Wiley-Blackwell
    Angewandte Makromolekulare Chemie 6 (1969), S. 24-38 
    ISSN: 0003-3146
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Description / Table of Contents: In this work various methods concerning the determination of compatibility of polymers are discussed. The conclusion is, that the earlier proposed “kinetical” method, besides the method of phase separation in common solution, is one of the surest methods of compatibility determination for polymers. However, over the latter, the kinetical method offers the advantage of rapidity and the possibility to predict the thermostability, the interactions of functional groups and the formation of solution in the solide state. While the interaction of functional groups may be established also by IR-spectroscopy, the other methods permit no conclusions of this kind. Generally it is very difficult to make statements on the formation of solution in the solid state on the basis of other methods of compatibility investigation. Quite useless, at least for our polymer mixtures, are the measurements of viscosity in concentrated as well as in dilute polymer solutions.
    Notes: In vorliegender Arbeit werden verschiedene Methoden für Verträglichkeitsbestimmungen von Polymeren vergleichend besprochen, wobei sich die früher vorgeschlagene kinetische Methode, neben der Phasentrennung in gemeinsamer Lösung, als eine der sichersten erweist. Gegen letztgenannte Methode bietet sie aber den Vorteil, daß sie viel schneller ist und auch Aussagen über Thermostabilität, Wechselwirkung von funktionellen Gruppen und Lösungsbildung im festen Zustand ermöglicht. Wenn die Wechselwirkung von funktionellen Gruppen auch IR-spektroskopisch eindeutig festgelegt werden kann, so erlauben andere Methoden diesbezüglich keine Schlüsse, und am schwersten ist es im allgemeinen, Aussagen über Lösungsbildung im festen Zustand auf Grund der Ergebnisse anderer Untersuchungsmethoden zu machen. Ganz unbrauchbar, zumindest in den von uns untersuchten Fällen, erweisen sich Viskositätsmessungen sowohl in konzentrierten als auch in verdünnten Polymerlösungen.
    Additional Material: 10 Ill.
    Type of Medium: Electronic Resource
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  • 5
    ISSN: 0025-116X
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Description / Table of Contents: The present paper deals with investigations on the thermal stability and the structure of some polychalcones by means of pyrolysis-gaschromatography. The decrease of electronic interaction due to the interruption of conjugation of the π-electronic system in the main chain of macromolecules is also reflected in the resulting chromatograms.
    Notes: In der vorliegenden Arbeit werden aus gaschromatographisch-pyrolytischen Untersuchungsergebnissen einige Aussagen über die Wärmebeständigkeit und Struktur von Polychalkonen abgeleitet. Es zeigt sich, daß die Abschwächung der Elektronenwechselwirkung durch Unterbrechung der Konjugation des π-Elektronensystems in der Hauptkette der Makromoleküle sich in den erhaltenen Chromatogrammen widerspiegelt.
    Additional Material: 4 Ill.
    Type of Medium: Electronic Resource
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  • 6
    Electronic Resource
    Electronic Resource
    New York, NY : Wiley-Blackwell
    Journal für Praktische Chemie/Chemiker-Zeitung 18 (1962), S. 121-128 
    ISSN: 0021-8383
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Es werden die bei der Untersuchung der thermischen Methankrackung in Gegenwart von Mo und W erhaltenen Ergebnisse besprochen. Es wird gezeigt, daß das W genau so wie die von anderen Forschern untersuchten Metalle die Dissoziation des Methans in seine Elemente begünstigt. Die Wirkung des Mo scheint komplizierter zu sein, da ein Vorwärmen des Methans in Gegenwart von Mo zu einer Steigerung der Acethylenkonzentration in den gasförmigen Reaktionsprodukten führt. Diese Wirkung des Molybdäns fällt mit dem Anwachsen der Zersetzungstemperatur.
    Additional Material: 4 Ill.
    Type of Medium: Electronic Resource
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  • 7
    Electronic Resource
    Electronic Resource
    New York : Wiley-Blackwell
    Die Makromolekulare Chemie 108 (1967), S. 182-192 
    ISSN: 0025-116X
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Description / Table of Contents: The kinetics of the dehydrochlorination of PVC are discussed. Thermogravimetric results show that the activation energy is influenced by both the degree of conversion and the rate of heating up the sample. The activation energy for initiation was found to have a far greater value (72.5 kcal/mole) than has generally been assumed. Other unexpected results related to this are also discussed.
    Notes: Die Kinetik der Dehydrochlorierung von PVC wird diskutiert. Thermogravimetrisch gewonnene Ergebnisse zeigen, daß die Aktivierungsenergie vom Umsatz und von der Geschwindigkeit, mit der die Probe aufgeheizt wird, abhängt. Die Aktivierungsenergie fü den Start hat einen viel größeren Wert (72,5 kcal/Mol) als allgemein angenommen wird. Abschließend werden auch einige unerwartete Ergebnisse zu klären versucht.
    Additional Material: 3 Ill.
    Type of Medium: Electronic Resource
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  • 8
    Electronic Resource
    Electronic Resource
    New York : Wiley-Blackwell
    Die Makromolekulare Chemie 132 (1970), S. 259-268 
    ISSN: 0025-116X
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Description / Table of Contents: The influences of the initiator- and the PVA-concentration as well as of the rate of stirring upon the reaction rate of the suspension polymerization of vinyl acetate were studied. This polymerization is determined by the rate of stirring and obeys own laws, so that it is not possible to identify the suspension polymerization with a “finely divided bulkpolymerization cooled with water”.
    Notes: Es wird der Einfluß der Initiator- und Polyvinylalkoholkonzentration sowie der Rührgeschwindigkeit auf die Reaktionsgeschwindigkeit der Perlpolymerisation des Vinylacetats untersucht und gefunden, daß die Perlpolymerisation von der Rührgeschwindigkeit abhängig ist. Aus diesem Ergebnis wird geschlossen, daß die Perlpolymerisation in diesem Fall nicht uneingeschränkt als eine „wassergekühlte Massenpolymerisation in fein verteiltem Zustand“ angesechen werden kann, sondern eigene Gesetzmäßigkeiten befolgt.
    Additional Material: 10 Ill.
    Type of Medium: Electronic Resource
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  • 9
    ISSN: 0025-116X
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Description / Table of Contents: The results of the kinetic isothermal, thermal-dynamic (i.e. with constant heating rate) and of the gaschromatographic-pyrolytic study of the thermal degradation of different polystyrenes show the mechanism of the degradation reaction to be complex and not simple depolymerisation. The kinetic parameters of the thermal degradation depend as well on the molecular weight as on the nature of the polystyrene and the degree of conversion. On these reasons, one observes under thermal-dynamic conditions an influence of the heating rate on the total activation energy.
    Notes: Die Ergebnisse der kinetisch-isothermen, thermisch-dynamischen (d. h. mit konstanter Aufheizgeschwindigkeit) und gaschromatographisch-pyrolytischen Untersuchungen des thermischen Abbaues von verschiedenen Polystyrolen lassen darauf schließen, daß der Abbaumechanismus komplexer Natur ist und nicht nur nach einem einfachen Depolymerisationsmechanismus verläuft. Die kinetischen Parameter des thermischen Abbaus sind sowohl vom Molekulargewicht als auch von der Art des Polystyrols und dem Umsatzgrad abhängig. Aus diesem Grunde wird unter thermisch-dynamischen Bedingungen auch ein Einfluß der Aufheizgeschwindigkeit auf die Bruttoaktivierungsenergie festgestellt.
    Additional Material: 6 Ill.
    Type of Medium: Electronic Resource
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  • 10
    Electronic Resource
    Electronic Resource
    New York : Wiley-Blackwell
    Die Makromolekulare Chemie 141 (1971), S. 127-144 
    ISSN: 0025-116X
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Description / Table of Contents: A critical discussion of the recommended methods for compatibility determinations in polymer mixtures by viscosimetry measurements shows, that in the case of the systems PVC/PVAc/cyclohexanone the best results are obtained by comparison of the parameters of interaction. In this case it is possible to estimate the optimal rapport of mixture. Extending the thermodynamic methods to polymer/polymer/solvent systems, it can be shown, that the systems studied here are characterized by far-reaching interactions, indicating an interaction of the functional groups of the polymer chains. This confirms our previous conclusion, that the polymers show two kinds of compatibility, that is, true compatibility of the macromoleculare chains and pseudo-compatibility due to the interactions of the functional groups.
    Notes: Es werden die in der Literatur empfohlenen Methoden für Verträglichkeitsbestimmungen in Polymergemischen aus Viskositätsmessungen an Hand des Systems PVC/PVAc/Cyclohexanon kritisch besprochen, wobei festgestellt wird, daß die besten Ergebnisse durch Vergleich der abgeleiteten Wechselwirkungsparameter erzielt werden, da optimale Mischungsverhältnisse ablesbar sind. Unter Ausdehnung der thermodynamischen Methoden auf Polymer/Polymer/Lösungsmittel-Systeme wird gezeigt, daß die untersuchten Systeme durch weitreichende Wechselwirkungen gekennzeichnet sind, was vor allem auf Wechselwirkungen zwischen den funktionellen Gruppen der Polymeren hindeutet. Diese Schlußfolgerung bestätigt unsere frühere Annahme, daß bei Polymeren zwischen einer Verträglichkeit der Makromolekülketten und einer Pseudoverträglichkeit infolge von Wechselwirkungen der funktionellen Gruppen zu unterscheiden ist.
    Additional Material: 5 Ill.
    Type of Medium: Electronic Resource
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