Singlet-oxygen diffusion

As shown in Table 1, intervesicular and intravesicular distances can be similar or even larger than the average singlet-oxygen diffusion length. This pos-... 

With the same fullerene-method, a quantitative conversion of methionine to the corresponding sulfoxides was achieved in about 40 s, using low power, white LED illumination. The reaction time is considerably shorter when compared to the batch procedure that requires, for the same process, about 1 h illumination and the use of a 300 W tungsten halogen lamp. This may be due to the narrow channels space in a microreactor, which favors singlet oxygen diffusion, thus determining a faster reaction. 

The phenomenon of fluorescence has been synonymous with ultraviolet (UV) and visible spectroscopy rather than near-infrared (near-IR) spectroscopy from the beginning of the subject. This fact is evidenced in definitive texts which also provide useful background information for this volume (see, e.g., Refs. 1-6). Consequently, our understanding of the many molecular phenomena which can be studied with fluorescence techniques, e.g., excimer formation, energy transfer, diffusion, and rotation, is based on measurements made in the UV/visible. Historically, this emphasis was undoubtedly due to the spectral response of the eye and the availability of suitable sources and detectors for the UV/visible in contrast to the lack of equivalent instrumentation for the IR. Nevertheless, there are a few notable exceptions to the prevalence of UV/visible techniques in fluorescence such as the near-IR study of chlorophyll(7) and singlet oxygen,<8) which have been ongoing for some years. 

The development of models requires more knowledge about the chemical, physical, morphologic, and flow properties of the mucus layer the kinetics of the reactions of ozone in the mucus and tissue layers and the molecular diffusivity of ozone in these layers. Similar information is needed for the hydroperozy and singlet oxygen, O, (a A), free radicals, which are reactive interme ates in photochemical smog. 

Both curves have similar shapes and it is clear that the photooxidation process is controlled by the diffusion of oxygen into the rose bengal sites in the polymer solution. These results suggest that when a snail amount of rose bengal is attached to the polymeric backbone (P-RB-51, 102 152 305) the quantum yield of of singlet oxygen formation is essentially the same (about 0.38). 

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