Photoisomerization inhibitor

Nakayarria, K., Kuru, N., Ohtsuka, M., Yokomizo, Y, Sakamoto, A., Kawato, H., Yoshida, K, Ohta, T., Hoshrno, K, Akimoto, K., Itoh, J., Ishida, H., Cho, A., Palme, M.H., Zhang, J.Z., Lee, V.J., and Watkins, W.J. (2004) MexAB-OprM specific efflux pump inhibitors in Pseudomonas aeruginosa. Part 4. Addressing the problem of poor stability due to photoisomerization... 

Experimental results gave the evidence of an efficient nitroxide radical inhibitor effect upon the sensitized cis-trans photoisomerization of DMAAS by quenching the sensitizer triplet state. The phosphorescence triplet lifetime of erythrosin B in PPDC membranes was measured to be 3 x 10 s. The experimental quenching rate constant of the cascade reaction kq and the rate constant of the triplet-triplet energy transfer kx evaluated in 2D terms were obtained as kq = (1.05 0.08) X 10 cm /(mols) and kx = (1.26 0.21) x 10 cm /(mols). Taking into consideration the efficiency of the triplet-triplet energy transfer y = 3.5 %, the rate constant of encounters between the sensitizer and the photochrome was found as ke = 3.4x 10 cm /(mols). 

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