A new method of analysis for S(IV) is described incorporating a counter-flow virtual impactor for collection and evaporation of cloud droplets with an SO2 analyzer. This technique allows analysis of aqueous S(IV) concentration in real-time and overcomes some sampling or analysis problems of conventional sampling with bulk cloud water collectors and wet chemical analysis methods. The technique is demonstrated by the correlated responses of the S(IV) instrument and instruments measuring physical properties of clouds while passing in and out of clouds. Measured aqueous S(IV) concentrations ranged from the detection limit (0.1 nmol per m3 of air) to 1.8 nmol m-3 in clouds in Ohio. S(IV) molar concentrations (moles/l of cloud water) were not calculable from these measurements, but can be calculated when a measurement of the liquid water content of the collected cloud water is made simultaneously.

Objective: There are no safety or absorption studies to guide topical timolol therapy for treatment of chronic wounds. This study was undertaken to address this gap. Approach: A prospective, observational, cross-sectional comparative study of timolol plasma levels in patients after topical administration to a chronic wound, compared with levels in patients after timolol ocular administration for the indication of glaucoma. Results: There was no statistically significant difference in the average plasma level of timolol in wound as compared with glaucoma patients. No bradycardia or wheezing was observed after administration. Innovation: We determined the single time point concentration of timolol in plasma 1 h after application of timolol 0.5% gel-forming solution to debrided chronic wounds, providing insight as to the safety of this emerging off-label treatment. Conclusion: The topical application of timolol for chronic wounds shares the same safety profile as the widely used application of ocular administration for glaucoma.