The role of peroxyl radicals in polyester degradation--a mass spectrometric product and kinetic study using the distonic radical ion approach.

Mass spectrometric techniques were used to obtain detailed insight into the reactions of peroxyl radicals with model systems of (damaged) polyesters. Using a distonic radical ion approach, it was shown that N-methylpyridinium peroxyl radical cations, Pyr(+)OO˙, do not react with non-activated C-H bonds typically present in polyesters that resist degradation. Structural damage in the polymer, for example small amounts of alkene moieties formed during the manufacturing process, is required to enable reaction with Pyr(+)OO˙, which proceeds with high preference through addition to the π system rather than via allylic hydrogen atom abstraction (kadd/kHAT > 20 for internal alkenes).

Prevalence and specificity of the enhancing effect of three types of interleukin 2 on T cell responsiveness in 97 lepromatous leprosy patients of mixed ethnic origin.

Peripheral blood mononuclear cells from 97 predominantly lepromatous leprosy patients and 11 control subjects were tested in a lymphoproliferative assay for response to Mycobacterium leprae (whole and sonicated), and sonicated M. vaccae, M. tuberculosis, and M.