The findings confirm that oxysterols are present in fatty streaks and advanced lesions and may arise from different cholesterol oxidation mechanisms, including free radical-mediated oxidation and enzymatic oxidation.

2-[(2E)-3-(4-tert-Butylphenyl)-2-methylprop-2-enylidene]malononitrile (DCTB) is a nonpolar, aprotic matrix and was used in the analysis of a variety of compounds by matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOFMS). The classes of compounds include coordination compounds, organometallics, conjugated organic compounds (including porphyrins and phthalocyanines), carbohydrates, calixarenes, and macrocycles. For some samples, comparisons are made with spectra acquired with the use of 1,8,9-trihydroxyanthracene (dithranol), 2,5-dihydroxybenzoic acid, and 2,4,6-trihydroxyacetophenone matrixes. Traditionally, the majority of these compounds would have been analyzed by fast-atom bombardment (FAB), liquid secondary ion mass spectrometry (LSIMS), or electrospray techniques, but this work shows that MALDI-TOFMS using DCTB has advantages over these techniques, particularly FAB and LSIMS. Certain limitations of DCTB are noted, for example, in the analysis of water-soluble compounds such as peptides, proteins, and oligonucleotides, and good working practices for the use of the matrix are also outlined.

Complexes of Re and Tc with 1,4,7-trithiacyclononane (9S3) differ from their later transition metal analogues in that their d 6 form ([M(9S3) 2 ] ϩ ) undergoes instantaneous C-S bond cleavage yielding ethene and [M(9S3)L] ϩ (L = SCH 2 CH 2 SCH 2 CH 2 S), a stable metal() thiolate complex, cleanly in aqueous solution. This contrast is interpreted as signifying increased π-back donation by Re and Tc, compared to later metals, into ligand C-S σ* orbitals. In order to validate this hypothesis within an established theoretical framework, and to compare the predicted relative C-S bond lability with relative experimental lability in a series of d 6 analogues, extended Hückel theory (EHT) was used to investigate the bonding (M = Mo, Tc, Ru, Rh or Pd) while electrospray mass spectrometry (ES-MS) was used to compare ethene loss, in a series of analogous complexes (M = Tc, Re, Ru or Os). The C-S overlap populations were smaller for M = Tc II and Tc I than for later metal() analogues, and were smaller for Tc I than for Tc II . Fragment molecular orbitals corresponding to C-S σ* were more highly populated for M = Tc II and Tc I than for later analogues, and also more highly populated for Tc I than for Tc II . ES-MS showed that ethene loss from Tc/Re I and Tc/Re II complexes occurred at much lower energies than from the Ru/Os II analogues. EHT supports the hypothesis that C-S activation is caused by π-back donation into C-S σ* orbitals, and correctly predicts that ethene loss occurs more readily from rhenium and technetium d 5 and especially d 6 complexes than from later transition metal analogues.

Growth in waste electrical and electronic equipment (WEEE) is posing increasing problems of waste management, partly resulting from its plastic content. WEEE plastics include a range of polymers, some of which can be sorted and extracted for recycling. However a nonrecyclable fraction remains containing a mixture of polymers contaminated with other materials, and pyrolysis is a potential means of recovering the energy content of this. In preparation for a life cycle assessment of this option, described in part 2 of this paper set, data were collected from trials using experimental pyrolysis equipment representative of a continuous commercial process operated at 800 °C. The feedstock contained acrylonitrile-butadiene-styrene and high impact polystyrene with high levels of additives, and dense polymers including polyvinylchloride, polycarbonate, polyphenylene oxide, and polymethyl methacrylate. On average 39% was converted to gases, 36% to oils, and 25% remained as residue. About 35% of the gas was methane and 42% carbon monoxide, plus other hydrocarbons, oxygen and carbon dioxide. The oils were almost all aromatic, forming a similar mixture to fuel oil. The residue was mainly carbon with inorganic compounds from the plastic additives and most of the chlorine from the feedstock. The results showed that the process produced around 70% of the original plastic weight as potential fuel.