Incorporation of the fluorescent, nonpermeant pH indicator pyranine into submitochondrial particles (pyranine-SMP) permitted monitoring of intravesicular pH changes brought about by proton translocation due to oxidation of respiratory chain substrates or to hydrolysis of ATP. Addition of oligomycin to beef heart pyranine-SMP was followed by a pH-independent quenching of pyranine fluorescence. Q...

established, the mechanism by which /?-carotene exerts a protective function against cancer remains unknown. However, there are several lines of evidence which suggest that the generation of reactive oxygen species may play an important role in the development of cancer [14]. The present work emphasizes that attention should be extended from /?-carotene to lycopene and other carotenoids. Lycope...

The excited-state quenching of zinc meso-tetrakis(4-sulfonatophenyl)porphyrin (ZnTPPS) by halide ions has been studied in water and various aqueous micellar solutions using both steady-state and time-resolved fluorescence techniques. The quenching efficiencies of the S(1) state of ZnTPPS ([small tau][approximate] 1.93 ns) by halide ions in homogeneous aqueous solution increase in the order Cl(-...

NPQ (non-photochemical quenching) is a fundamental photosynthetic mechanism by which plants protect themselves against excess excitation energy and the resulting photodamage. A discussed molecular mechanism of the so-called feedback de-excitation component (qE) of NPQ involves the formation of a quenching complex. Recently, we have studied the influence of formation of a zeaxanthin-chlorophyll ...

Many components use oil quenching to achieve consistent and repeatable mechanical and metallurgical properties and predictable distortion patterns. The reason oil quenching is so popular is due to its excellent performance results and stability over a broad range of operating conditions. Oil quenching facilitates hardening of steel by controlling heat transfer during quenching, and it enhances ...

High-pt particles produced in nucleus-nucleus collisions constitute a powerful tool to study the medium properties. The energy loss resulting from the propagation of these particles in the produced medium translates into a suppression of the high-pt yields. These effects are usually associated to medium-induced gluon radiation which, in turn, predicts a broadening of the jet-like signals. Both ...

resonance light scattering (rls) intensity of silver nanoparticles in the presence of sodium dodecylsulphate was quenched on addition of sulfasalzine. the quenching extent was shown to be proportional to the sulfasalazine concentration. effect of different parameters such as ph, volume and kind of buffer, silver nanoparticles concentration, sodium dodecylsulphate (sds) concentration, and waitin...

In this investigation the fluorescence quenching of fluorescent probe molecules situated within surfactant micelles was examined. The hydrophobic polyaromatic hydrocarbon benzo(a)pyrene (B(a)P) and the more polar 6-propionyl-2-(dimethylamino)-naphthalene (PRODAN) were used to assess the effect of high quencher concentration on the quenching process in micelles. Using the surfactant systems sodi...