Co- and terpolymers of N-isopropylacrylamide exhibit inverse temperature solubility in water with the polymer's lower critical solution temperature (LCST) being dependent on the polymer's microstructure and the concentration of salt in the water solvent. This solubility behavior has been used to prepare “smart” recoverable homogeneous catalysts and substrates. These catalysts' activity reversibly turns first off and then on as the temperature is first raised and then lowered due to changes in the polymer support's solubility. Such catalysts can be recovered by heating the aqueous solution or by adding brine. Catalysts prepared include both phosphine-ligated transition metal catalysts and acid catalysts. The transition metal catalysts are active in alkene hydrogenation, C−C coupling, and allylic substitution reactions. The acid catalysts are active in acetal hydrolysis. Substrates can be attached to these polymers and their activity likewise can be turned off and on by heating or cooling. Substrate activity on such supports can equal that of a low molecular weight analogue. NMR spectroscopic studies show that a vinyl group bound to PNIPAM has peaks whose line widths in 1H NMR spectroscopy are like those of a low molecular weight compound when a nine-carbon tether chain is used to attach the vinyl group to PNIPAM.

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Biomarkers of exposure (BoE) can help evaluate exposure to combustion-related, tobacco-specific toxicants after smokers switch from cigarettes to potentially less-harmful products like electronic nicotine delivery systems (ENDS). This paper reports data for one (Vuse Solo Original) of three products evaluated in a randomized, controlled, confinement study of BoE in smokers switched to ENDS. Subjects smoked their usual brand cigarette ad libitum for two days, then were randomized to one of three ENDS for a 7-day ad libitum use period, or to smoking abstinence. Thirteen BoE were assessed at baseline and Day 5, and percent change in mean values for each BoE was calculated. Biomarkers of potential harm (BoPH) linked to oxidative stress, platelet activation, and inflammation were also assessed. Levels decreased among subjects randomized to Vuse Solo versus Abstinence, respectively, for the following BoE: 42–96% versus 52–97% (non-nicotine constituents); 51% versus 55% (blood carboxyhemoglobin); and 29% versus 96% (nicotine exposure). Significant decreases were observed in three BoPH: leukotriene E4, 11-dehydro-thromboxane B2, and 2,3-dinor thromboxane B2 on Day 7 in the Vuse Solo and Abstinence groups. These findings show that ENDS use results in substantially reduced exposure to toxicants compared to smoking, which may lead to reduced biological effects.

We identified a set of five proteins as potential biomarkers that can inform of inflammation status due to tobacco usage. Our findings contribute a better understanding of how the use of different tobacco products contributes to inflammation.

This study is the first to report snus MLE under normal conditions of use in a group of adult, U.S. snus consumers. On average, approximately 60%-90% of the amounts of nicotine, TSNAs, and B[a]P initially present in a snus pouch remained in the pouch after use by snus consumers in this study. The results from this study provide a preliminary assessment of exposure to constituents present in snus, which is potentially useful in risk assessment.