Photooxidation of extramitochondrial cy-aspartate aminotransferase in the presence of methylene blue or Rose bengal leads to a loss of enzymatic activity which follows fist order kinetics. Amino acid analysis shows that histidine is the only amino acid residue significantly affected by photooxidation. Of the 8 hi&dine residues present in the enzyme monomer, 2 are oxidized rapidly at a rate iden...

Photooxidation of PET fibres or films creates fluorescent by-products which are separated in wavelength from the intrinsic fluorescence o f PET. An experimental technique is described which allows the study of the dependence of photooxidation on wavelength by the fluorescence of only a single specimen. Furthermore, using polarized fluorescence, the conservation of photoselected orientation can ...

The valence state of thallium determines its toxicity, distribution and mobility. Tl(I) can be oxidized to Tl(III) under photoirradiation of the high-pressure mercury arc lamp and solar light. A photooxidation experiment of thallium showed that the photooxidation rate could be affected by the pH of the solution, and the intensity and wavelength of the light source. Lowering the pH and increasin...

The photooxidation of thebaine (3) with a sun lamp affords two main products: hydrodibenzofuran 10 (major) and benzofuran 11 (minor). The latter compound becomes predominant if a Hg lamp is used instead of a sun lamp. The formation of 10 proceeds via an endoperoxide intermediate that undergoes oxidation at the nitrogen atom. Protection of the nitrogen either by protonation or quaternization pre...

This study evaluates the significance of glyoxal acting as an intermediate species leading to secondary organic aerosol (SOA) formation from aromatic hydrocarbon photooxidation under humid conditions. Rapid SOA formation from glyoxal uptake onto aqueous (NH4)2SO4 seed particles is observed in agreement with previous studies; however, glyoxal did not partition significantly to SOA (with or witho...

The influence of activated carbon on the activity of TiO2 in toluene photooxidation was studied to verify the efficiency of both materials working ensemble. Results showed that surface pH and more strongly the surface area of activated carbon influence the TiO2 photoactivity. Results suggest that toluene adsorbed on carbon diffuses to TiO2 where photooxidation takes place. In conclusion, TiO2-a...

Visible-light harvesting cyclometalated Ir(III) complexes were used as (1)O(2) sensitizers for the photooxidation of 1,5-dihydroxynaphthalene (DHN) and substantially improved photooxidation capability was observed compared to the conventional Ir(III) complex sensitizers that show no visible light-harvesting capabilities.

Two aquatic fulvic acids and one soil humic acid were irradiated to examine the resulting changes in the redox and photochemical properties of the humic substances (HS), the relationship between these changes, and their relationship to changes in the optical properties. For all HS, irradiation caused photooxidation, as shown by decreasing electron donating capacities. Photooxidation was accompa...

photooxidation as an important process, which significantly affects the service life of the polypropylene products, has been the subject of much theoretical and experimental study. pigments used often change the light stabilities of polypropylene. out-door applications of pigmented polypr-opylene are now increasingly developed in products such as artificial grass. the aim of this work is to exa...

O2-evolution activity and the Mn complex can be reconstituted in photosystem II by a process called photoactivation. We have studied the elementary steps in photoactivation by using electron paramagnetic resonance spectroscopy to probe electron transport in Mn-depleted photosystem II membranes. The electron donation reactions in Mn-depleted photosystem II were found to be identical with those i...