A nitrogen dioxide delivery system for biological media

Uptake and diffusion of plasma-generated reactive nitrogen species through keratinized membrane

“…For the concentrations of NO 2 measured in figure 1 and the values of the relevant forward and reverse rate constants (K 1,gas = k 1 /k −1 = 6.86 atm −1 ) [20], the calculated dimer concentration is approximately two orders of magnitude below that of NO 2 , as shown in figure 1. Due to the rate constants and the presence of a dense, porous membrane, Knudsen diffusion was assumed within the hoof membrane, allowing for gas-phase dimerization within the hoof volume to be ignored.…”

“…Due to the apparent absence of real-time monitoring of these species under hydrolysis conditions, most analyses rely on theoretical estimates in order to determine chemical mechanisms and rates [22,[38][39][40]. Recently, Deen's group reported that the accumulation rates of NO − 2 and NO − 3 in buffered aqueous solutions with exposure to NO 2 gas follow the stoichiometry of reaction (R4) [20]. Their reported experimental measurements were consistent with these assumptions.…”

“…The uptake and hydrolysis of gas phase NO 2 in liquid water play important roles in various fundamental atmospheric and environmental chemistries [20,22,30]. Due to the apparent absence of real-time monitoring of these species under hydrolysis conditions, most analyses rely on theoretical estimates in order to determine chemical mechanisms and rates [22,[38][39][40].…”

“…where k 2 is the reaction rate coefficient in reaction (R4) (assumed to be the same as in reaction (R3)), given as 10 3 s −1 [20]. The detailed boundary conditions expressions using total reactive nitrogen concentration are found in [20].…”

Chemistry meets biology in colitis-associated carcinogenesis

“…The most rigorous conditions are achieved by using of NO and O 2 -permeable polydimethylsiloxande (Silastic) tubing to deliver gases at constant and predictable rates. These delivery systems are specifically designed and optimized to provide controlled, steady state concentrations of NO, O 2 , and NO 2 , thereby mimicking the chemical environment thought to exist in inflamed tissues [136–140]. The range of estimated concentrations of NO in inflamed tissue, as obtained by mathematical modeling (Figure 3), are in reasonable agreement with those found to be cytotoxic in studies applying NO and O 2 via Silastic tubing to cell culture media (Figure 4 D).…”