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  • 11
    Electronic Resource
    Electronic Resource
    Microcalorimetric and FT-IR spectroscopic study of benzene adsorption on α-Fe2O3 and γ-Al2O3 (1984)
    Springer
    Journal of thermal analysis and calorimetry 29 (1984), S. 745-753 
    Details
    ISSN: 1572-8943
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Zusammenfassung Die Adsorption von Benzol anα-Fe2O3- undγ-Al2O3-Pulvern bei Raumtemperatur wurde mittels Wärmefluß-Kalorimetrie und FT-IR-Spektroskopie untersucht. Beim Eisenoxid folgt auf dem Chemisorptions-Verbrennungs-Schritt ein bei Raumtemperatur reversibler, stark exothermer Adsorptionsschritt. Aluminiumoxid besitzt einige Oxydationszentren, sofern keine reduzierende Vorbehandlung erfolgt. Zwei aufeinanderfolgende reversible Adsorptionsschritte treten auf und werden der Wechselwirkung mit zwei verschiedenen Typen von Oberflächenhydroxylgruppen zugeschrieben.
    Abstract: Резюме Методом микрокалори метрии теплового пот ока и ИК спектроскопии с фу рье преобразованием исс ледована при комнатн ой температуре адсорбц ия бензола наα-Fe2O3 иγ-Аl2О3. В случае о киси железа стадия хемисорбция-горение сопровождалась последующей высокот емпературной стадие й адсорбции, обратимой при комнат ной температуре. На образцах окиси алю миния, не подвергнуты х предварительной обр аботке, существует нескольк о центров горения. Последовательно наб людались две обратим ые стадии адсорбции, кот орые были объяснены к ак результат взаимодей ствия с двумя различн ыми типами поверхностны х гидроксильных груп п.
    Notes: Abstract The adsorption of benzene at room temperature onα-Fe2O3 and onγ-Al2O3 powders was investigated by heat-flow microcalorimetry and FT-IR spectroscopy. On iron oxide a chemisorption-combustion step is followed by a highly exothermic adsorption step, reversible at r.t. Few combustion centres exist on alumina if reducing pretreatment is not carried out. Two reversible adsorption steps are subsequently observed and were interpreted as due to interaction with two different types of surface hydroxy groups.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01913533
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  • 12
    Electronic Resource
    Electronic Resource
    Quantitative DTA of epoxy adhesives of technological interest (1981)
    Springer
    Journal of thermal analysis and calorimetry 21 (1981), S. 299-307 
    Details
    ISSN: 1572-8943
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Résumé On a déterminé, pour cinq adhésifs époxy de composition inconnue, les températures de transition vitreuseT g et les effets thermiques de polymérisationΔH. A partir de la variation deΔH en fonction du temps de recuit et par une méthode de calcul itératif, un ordre cinétique phénoménologique de la vitesse de polymérisation à 100° a pu être obtenu. Pour la plupart des adhésifs étudiés l'existence d'un pic double de polymérisation et d'une double transition vitreuseT g permet de supposer qu'il s'agit de copolymères greffés.
    Abstract: Zusammenfassung Die Glas-Übergangstemperaturen (T g) und dieΔH thermische Effekte der Polymerisation wurden für fünf Epoxy-Klebstoffe unbekannter Zusammensetzung bestimmt. Aus den TrendsΔH gegenübert cure war es möglich eine phenomenologische kinetische Ordnung der Polymerisationsgeschwindigkeit bei 100° durch ein iteratives Berechnungsverfahren zu ermitteln. Für die meisten untersuchten Klebstoffe besteht der Grund — Doppelpeak der Polymerisation und doppeltesT g-Signal — sie als Pfropfcopolymere zu betrachten.
    Notes: Abstract The glass transition temperatures,T g, and thermal effects of polymerization,ΔH, have been determined for five epoxy adhesives of unknown composition. From the trendsΔH vs./t cure it has been possible to attain a phenomenological kinetic order of the polymerization rate at 100° through an iterative calculation procedure. For most of the investigated adhesives there are reasons (double peak of polymerization and doubleT g signal) to assume that they are graft copolymers.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01914214
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    Paper (German National Licenses)
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  • 13
    Electronic Resource
    Electronic Resource
    Pyruvate-dehydrogenase complex in ataxic patients: Enzyme deficiency in ataxic encephalopathy plus lactic acidosis and normal activity in Friedreich ataxia (1982)
    Springer
    Neurological sciences 3 (1982), S. 317-321 
    Details
    ISSN: 1590-3478
    Keywords: Pyruvate-dehydrogenase ; Friedreich ataxia ; lactic acidosis
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Description / Table of Contents: Sommario Il complesso enzimatico piruvico-deidrogenasi (PDHC) è stato misurato in fibroblasti coltivati da 12 pazienti con atassia di Friedreich ed 1 paziente con acidosi lattica e atassia. Le attività enzimatiche ottenute con diversi metodi di estrazione del PDHC sono stati confrontati. La estrazione con Triton-X-100 permetteva di ottenere attività enzimatiche da 5 a 10 volte più elevate di quelle ottenute con i metodi precedenti. Con questo sensibile metodo l'attività PDHC era molto ridotta nei fibroblasti del paziente con acidosi lattica e atassia: l'attività era invece normale nei fibroblasti dei pazienti con atassia di Friedreich. La attivazione del PDHC nei fibroblasti dei pazienti con Friedreich era normale.
    Notes: Abstract Pyruvate dehydrogenase complex (PDHC) activity was measured in cultured fibroblasts from 12 patients with Friedreich's ataxia (FA), and in 1 patient with lactic acidosis and ataxia. The activities obtained after extraction of PDHC by different methods were compared. Triton-X-100 extraction yielded enzyme activities 5 to 10 times greater than those obtained with the older methods. With this sensitive technique, PDHC activity was markedly deficient in fibroblasts from the patient with lactic acidosis and ataxia but it was normal in the fibroblasts from FA patients. Mg ++ activation of the PDHC in FA fibroblasts was normal.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF02043580
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    Paper (German National Licenses)
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