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  • Articles: DFG German National Licenses  (27)
  • Chemistry  (26)
  • Luminol luminescence induced by luminol  (1)
  • 1
    Electronic Resource
    Electronic Resource
    Amsterdam : Elsevier
    Free Radical Biology and Medicine 16 (1994), S. 833-837 
    ISSN: 0891-5849
    Keywords: Evaluation of Trolox ; Free radicals ; Horseradish peroxidase ; Luminol luminescence induced by luminol ; Quenching of luminol luminescence ; SOD activity
    Source: Elsevier Journal Backfiles on ScienceDirect 1907 - 2002
    Topics: Biology , Chemistry and Pharmacology , Medicine
    Type of Medium: Electronic Resource
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  • 2
    Electronic Resource
    Electronic Resource
    Bognor Regis [u.a.] : Wiley-Blackwell
    Journal of Polymer Science Part A: Polymer Chemistry 32 (1994), S. 1649-1655 
    ISSN: 0887-624X
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The photoinitiation efficiency of the fluorenone/triethylamine (TEA) system in the polymerization of methylmethacrylate (MMA) has been evaluated as a function of the monomer concentration, the amine concentration, and the polarity of the reaction medium. The polymerization proceeds readily in low polarity media (benzene/monomer), but it is negligible in more polar solvents (acetonitrile/monomer). The polymerization rate increases with the amine concentration up to 0.01 M TEA. Further increase in amine concentration produces a decrease in the polymerization rate. A similar behavior was observed for the fluorenone photoreduction yield and the yield of fluorenone derived radicals. All these processes are considered to involve the excited triplet, while quenching of the excited singlet by the amine decreases the rate of these processes. However, the decrease in photoinitiation efficiency observed at high amine concentration is larger than that expected from the singlet quenching extent, as estimated from the effect of the amine on the fluorescence yield under the same experimental conditions. This discrepancy indicates that other process(es) must contribute to the protection afforded by high amine concentrations. Quenching of the charge transfer intermediate by the amine is postulated as a competitive process that could explain the above mentioned effects. © 1994 John Wiley & Sons, Inc.
    Additional Material: 4 Ill.
    Type of Medium: Electronic Resource
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  • 3
    Electronic Resource
    Electronic Resource
    Bognor Regis [u.a.] : Wiley-Blackwell
    Journal of Polymer Science Part A: Polymer Chemistry 34 (1996), S. 1941-1944 
    ISSN: 0887-624X
    Keywords: photoinitiation ; cyclododecanones ; photopolymerization ; Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: To establish their potential as source of biradicals to initiate free-radical polymerization, 2-methyl- and 2,2,12-trimethylcyclododecanones were photolyzed in the presence of styrene. The initiation efficiency of both ketones is low - 0.03. The molecular weight of the obtained polymer is ca. 25% higher than that obtained employing photoinitiators that produce monoradicals. This difference is explained in terms of a mixed polymerization mechanism comprising mono- and biradicals. © 1996 John Wiley & Sons, Inc.
    Additional Material: 1 Ill.
    Type of Medium: Electronic Resource
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  • 4
    Electronic Resource
    Electronic Resource
    Bognor Regis [u.a.] : Wiley-Blackwell
    Journal of Polymer Science Part A: Polymer Chemistry 27 (1989), S. 139-145 
    ISSN: 0887-624X
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The interaction of benzil and thioxanthone triplets with triethylamine leads to the production of free radicals that are able to initiate the polymerization of methylmethacrylate and vinyl acetate. The process is mediated by a charge transfer complex. The initiation efficiency is higher in benzene than in acetonitrile, a result explained in terms of competition between back electron transfer, production of free ions and ketyl radical formation. The initiation efficiency decreases when the carbonyl concentration increases, because of the occurrence of a radical molecule reaction such as The α-hydroxy radicals produced in this reaction are unable to initiate the polymerization chain.
    Additional Material: 2 Ill.
    Type of Medium: Electronic Resource
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  • 5
    Electronic Resource
    Electronic Resource
    Bognor Regis [u.a.] : Wiley-Blackwell
    Journal of Polymer Science Part A: Polymer Chemistry 26 (1988), S. 2827-2830 
    ISSN: 0887-624X
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The polymerization of methyl methacrylate photosensitized by benzion methyl ether over a wide range of initiator absorbances was investigated. Both the polymerization rate and the polymer molecular weight distribution are modified by stirring the solution at c.a. 700 rpm. The results obtained can be explained in terms of an inhomogeneous distribution of the polymeric macroradicals under nonstirred conditions. This effect can be related to the attenuation of the light beam across the reactor, and hence is determined by the optical density of the reacting mixture.
    Additional Material: 1 Ill.
    Type of Medium: Electronic Resource
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  • 6
    Electronic Resource
    Electronic Resource
    Bognor Regis [u.a.] : Wiley-Blackwell
    Journal of Polymer Science Part A: Polymer Chemistry 28 (1990), S. 2465-2474 
    ISSN: 0887-624X
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Addition of triethylamine (TEA) notably increases the efficiency of anthraquinone (AQ) as photoinitiator of methyl methacrylate (MMA) free radical polymerization in nonpolar solvents. On the other hand, when alcohols or acetonitrile are employed as solvents the addition of TEA decreases the AQ photoinitiated polymerization rate. The polymerization efficiency measured in nonpolar solvents decreases when the MMA concentration increases. These results are explained in terms of quenching of the AQ-TEA charge transfer complex by MMA. This conclusion is supported by the decrease in AQ photoconsumption and AQH2 formation produced by the monomer addition.
    Additional Material: 5 Ill.
    Type of Medium: Electronic Resource
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  • 7
    Electronic Resource
    Electronic Resource
    Bognor Regis [u.a.] : Wiley-Blackwell
    Journal of Polymer Science Part A: Polymer Chemistry 36 (1998), S. 207-208 
    ISSN: 0887-624X
    Keywords: photoinitiated polymerization ; initiator absorbance ; metal complex ; Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: No abstract.
    Additional Material: 1 Ill.
    Type of Medium: Electronic Resource
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  • 8
    Electronic Resource
    Electronic Resource
    New York : Wiley-Blackwell
    Journal of Bioluminescence and Chemiluminescence 12 (1997), S. 141-148 
    ISSN: 0884-3996
    Keywords: lipid peroxidation ; aldehydes ; chemiluminescence ; oxidative stress ; Chemistry ; Biochemistry and Biotechnology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Chemistry and Pharmacology
    Notes: The effect of several aliphatic aldehydes on lipid peroxidation was evaluated by measuring the oxygen uptake rate, thiobarbituric acid-reactive products formation and the emitted visible chemiluminescence intensity. Measurements were carried out in brain homogenates and erythrocyte plasma membrane and liver microsomal fractions. In all systems studied, aldehydes (25 mmol/L) (e.g. acetaldehyde, 2,2-dimethylpropanal), increased the intensity of the luminescence associated with the oxidation process. In contrast, aldehyde incorporation decreased TBARS production and the rate of oxygen uptake. The increased luminescence intensity is explained in terms of secondary reactions of aldehyde derived free radicals. These results clearly indicate that extreme care must be exercized in the intepretation of chemiluminescence data in the presence of aldehydes. © 1997 John Wiley & Sons, Ltd.
    Additional Material: 8 Ill.
    Type of Medium: Electronic Resource
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  • 9
    Electronic Resource
    Electronic Resource
    New York, NY [u.a.] : Wiley-Blackwell
    Cell Biochemistry and Function 4 (1986), S. 61-68 
    ISSN: 0263-6484
    Keywords: Red blood cell ; oxygen uptake ; t-butyl hydroperoxide ; haemoglobin status ; antioxidants ; Chemistry ; Biochemistry and Biotechnology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: Oxygen uptake by erythrocytes exposed to t-butyl hydroperoxide (t-BHP) exhibited an induction period. The rate of oxygen consumption can be reduced by antioxidants and blood plasma. The induction time was not appreciably modified by the antioxidants tested, however, plasma increased it by a factor of two. The in vivo pretreatment with diethyl maleate (0·6 g kg-1) produced increased rates of oxygen uptake without changes in the induction period, while vitamin E (12·5 mg kg-1) elicited lower oxygen consumption rates and longer induction times, compared to those observed in cells from control rats upon addition of the hydroperoxide. These results suggest that the antioxidants tested on the t-BHP lipid peroxidation in erythrocyte suspensions act as inhibitors and/or retarders of the process. Furthermore, lipid peroxidation induced in these conditions seems to depend upon the haemoglobin status of the cells as oxygen uptake, malondialdehyde production and chemiluminescence were significantly higher in methaemoglobin-containing cells than in those containing oxyhaemoglobin.
    Additional Material: 5 Ill.
    Type of Medium: Electronic Resource
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  • 10
    Electronic Resource
    Electronic Resource
    New York : Wiley-Blackwell
    Journal of Polymer Science Part B: Polymer Letters 8 (1970), S. 515-518 
    ISSN: 0449-2986
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Additional Material: 2 Ill.
    Type of Medium: Electronic Resource
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