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  • 1
    Electronic Resource
    Electronic Resource
    Observed phase transformations of oxalate-derived lead monoxide powder (1991)
    Springer
    Journal of thermal analysis and calorimetry 37 (1991), S. 2555-2566 
    Details
    ISSN: 1572-8943
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Zusammenfassung Zweck dieser Untersuchung ist, das Wesen der Phasenumwandlungen von Bleimonoxidpulver zu ergründen. Bleimonoxid wird durch Calzinierung von Bleioxalat hergestellt und seine Phasenumwandlungen wurden mittels Röntgendiffraktion, DSC und TG untersucht. Die Analyse zeigt, daß die für das aus Oxalat erhaltene Bleimonoxidpulver beobachteten Phasenumwandlungen stark von der Heizatmosphäre abhängen. Wird die Temperatur ab Raumtemperatur mit einer Aufheizgeschwindigkeit von 1/min erhöht, geht Bleimonoxid in Stickstoff im Temperaturbereich 525°–575°C eine rekonstruktive Bleiglätte-Massicot-Phasenumwandlung ein. In Luft wird die bei Raumtemperatur metastabile Bleiglätte bei 350°C langsam zu Pb3O4 oxidiert und dann bei 560°C schnell zu Bleiglätte reduziert. Bei Temperaturen über 560°C wird Bleiglätte in Massicot umgewandelt. Bei Aufheizgeschwindigkeiten von über 10/min kann keine Bildung von Pb3O4 beobachtet werden.
    Notes: Abstract The purpose of this study is to elucidate the nature of the phase transformations of lead monoxide powder. Lead monoxide is prepared by calcination of a lead oxalate precursor salt, and its phase transformations are studied using X-ray diffraction (XRD), differential scanning calorimetry (DSC) and thermal gravimetric analysis (TG). Analysis reveals that the phase transformations observed for oxalate-derived lead monoxide powder are highly dependent on the firing atmosphere. In nitrogen, as the temperature is increased 1 deg/min from room temperature, lead monoxide undergoes a reconstructive litharge-to-massicot phase transformation in a temperature range of 525–575°C. In air, litharge, metastable at room temperature, slowly oxidizes to the Pb3O4 phase at a temperature of 350°C and rapidly reduces to litharge at 560°C. At temperatures greater than 560°C, litharge converts to massicot. With heating rates of 10 deg/min or higher, formation of Pb3O4 is not observed.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01912800
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  • 2
    Electronic Resource
    Electronic Resource
    The effect of exercise and restraint on pectoral muscle metabolism in pigeons (1997)
    Springer
    Journal of comparative physiology 167 (1997), S. 197-203 
    Details
    ISSN: 1432-136X
    Keywords: Key words Avian muscle  ;  Lactate dehydrogenase  ;   Training  ;  Immobilization  ;  Pigeon
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Abstract The effect of various activity regimes on metabolism of pigeon pectoralis was examined by measurement of blood lactate following exercise, total lactate dehydrogenase activity of pectoral muscle, and proportions of specific isoenzymes of pectoral muscle lactate dehydrogenase. Sprint-trained birds had the highest pectoral muscle lactate dehydrogenase activity (1409 IU · g−1 wet tissue), while endurance-trained birds had the highest peak lactate levels (287 mg · dl−1, extrapolated from decay curves) and fastest half-time of the lactate response (4.8 min) following exercise, but the lowest lactate dehydrogenase activity (115 IU · g−1 wet tissue). Immobilization of one wing for 3 weeks following endurance training produced a marked increase in lactate dehydrogenase activity of the immobilized muscle, compared to that in the contralateral pectoralis and endurance-trained muscle. Aerobic forms of the lactate dehydrogenase enzyme (that favor conversion of lactate to pyruvate) predominated in pectoral muscle of endurance-trained birds, while cage-confined birds exhibited primarily the anaerobic isoenzymes. These results demonstrate that conversion of pectoral muscle lactate dehydrogenase isoenzymes, total lactate dehydrogenase activity, and half-time of lactate response after exercise is dependent on activity regime in pigeons. In this respect, pigeon pectoral muscle responds to training and disuse in a manner similar to that of mammalian skeletal muscle.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/s003600050065
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