Pulsradiolytische Untersuchungen radikalischer Reaktionen mehrfach ungesaettigter Fettsaeuren in waessriger Loesung

SIGLEAvailable from TIB Hannover: DW 5625 / FIZ - Fachinformationszzentrum Karlsruhe / TIB - Technische InformationsbibliothekDEGerman

Literature storage and retrieval system using a table-top computer.

A dialogue-program is described which handles crossreferences within a given set of keywords, author names, journal names and specified reference numbers. It uses the set of basic statements available in a WANG 2200T version which is connected to a floppy-diskette. The program has rather convenient features for editing and processing of literature data

Fatty acid peroxyl radicals: Their generation and reactivities.

The formation and reactivity of fatty acid peroxyl radicals, obligatory intermediates in lipid peroxidation, are reviewed and new data, obtained by the pulse radiolysis technique, are presented. From previous studies employing steady-state systems for the generation of the peroxyl radicals, detailed mechanisms of the initial steps are known and a limited number of rate constants with phenolic antioxidants, including vitamin E (α-tocopherol), were determined - all in organic solvents. In contrast, pulse radiolysis allows the generation of the fatty acid peroxyl radicals as well as the determination of the rate constants of their reactions with each other and with phenolic antioxidants in aqueous solutions. Using kinetic modelling, we also calculated the rate constants for adduct formation between linoleic acid peroxyl radicals and aroxyl radicals derived from the flavonols kaempferol and quercetin

The reaction of sulfite radical anion with nucleic acid components.

The sulfite radical anion (SO3 -) is the first intermediate in the autoxidation of sulfite to sulfate. Using competition kinetics, its reactivities with the nucleic acid bases and the corresponding nucleosides were investigated. The second order rate constants were found to be rather low, k < 1 × 106dm3mol-1s-1 at pH 7. As a competitor, the carotenoid crocin was used, which was found to be bleached very efficiently by SO3 - (k = 1.0 × 109dm3mol-1S-1)

The reaction of sulfite anion radical (SO^.- ₃) with polyunsaturated fatty acids.

Using the pulse radiolysis technique, SO.- 3 was produced in aqueous solution by the reaction of SO2- 3 with either .OH or the (pseudo-) halide radicals N. 3, Br.- 3, and (SCN).- 2; for the latter reactions rate constants were measured. The reaction of SO.- 3 with linoleic, linolenic, and arachidonic acids was monitored using the strong absorption of the pentadienyl radical, one possible primary reaction product. In micellar systems no detectable reaction took place, however, monomeric fatty acids were observed to react with SO.- 3. Lower limits of the rate constants for SO.- 3 attack derived from the data are 1 × 105, 8 × 105, and 1.3 × 106 (dm3 mol-1 s-1) for linoleate, linolenate, and arachidonate, respectively

Pulse radiolysis equipment: A setup for simultaneous multiwavelength kinetic spectroscopy.

A setup for pulse radiolysis experiments is described consisting of the following main components: an array of 15 photomultipliers attached to a spectrograph (allowing 4032 spectra to be recorded with a time resolution of 500 ns per spectrum), self-regulating high-voltage supply for the photomultipliers, computer-controlled solution mixing and dispensing system, and provisions for continuous dose variation of the FEBETRON-accelerator electron beam. The general performance of the system is discussed and construction or electronic details are given for special components