No abstract

No abstract

This work was concerned with the simultaneous measurement of the combination coefficients b and 70, between small ions and aerosol particles and between small ions and uncharged aerosol particles respectively, for different particle radii.The ion-ion mutual repulsion coefficient y was first evaluated from 14 plots of small ion decay in an aerosol-free mylar vessel, which gave a mean experimental value of 2.39 (k 0.14) x 10-8 cm3 s-1.The decay of ions in the presence of aerosol particles in the mylar vessel was recorded and compared with a family of computed theoretical ion-aerosol decay curves to determine b. 70 could then be determined from the concentration of uncharged nuclei present. In the ten experiments carried out b ranged from 0.50 to 2 . 2 4~ 10-8 cm3 s-1 and 70 ranged from 0.33 to 2-39 x 10-6 cm3 s-1, for corresponding radii of 1.26 and 4.0 x 10-6 cm.Satisfactory agreement was found between the b and 70 versus radius results and various theoretically computed values. Possible reasons for discrepancies between theory and experiment are indicated.

No abstract

The leaving groups of serine esterase substrates and organophosphorus inhibitors bind to different loci at the enzyme active site. Kinetic proof of this general conclusion is presented in the case of acetylcholinesterase reactions. The proposed model for acetylcholinesterase active site provides a new stereochemical mechanism for the phosphorylated enzyme reactivation.