Lactisole sweet water taste is unaffected by prior sweet receptor activation.

<p>Log₁₀ sweetness ratings are shown for solutions of <b>(a)</b> sucrose and <b>(b)</b> neotame sampled with the tongue tip in 4 conditions: Suc or Neot + Lac: a <i>still</i> lactisole + sweetener mixture (white bars); Lac→Suc or Neot: a <i>still</i> solution of lactisole before a <i>still</i> solution of the sweetener (gray bars); Suc or Neot + Lac → H₂O: a <i>still</i> sweetener + lactisole mixture followed by a <i>flowing</i> water rinse (hatched white bars); and Lac→Suc or Neot→H₂O: a <i>still</i> solution of lactisole before a <i>still</i> solution of the sweetener followed by a <i>flowing</i> water rinse (hatched gray bars). Shown for comparison is the SWT produced by a <i>flowing</i> water rinse after lactisole alone (dashed line). Vertical bars are the standard errors of the log₁₀ means (SEMs).</p

Effects of different sweeteners on the lactisole sweet water taste.

<p>Five different sweeteners (CYCL = cyclamate, FRUC = fructose, SACC = saccharin, SUCRA = sucralose, NHDC = neohesperidin dihydrochalcon) were presented in the 2 treatment conditions of experiment 2: in mixture with lactisole <b>(a-e)</b> or after lactisole <b>(f-j)</b>. The data for the lactisole SWT is shown in each graph (open circles) for comparison with the SWT produced in the treatment conditions (filled circles). In graphs <b>(a-e)</b> L/M on the x-axis indicates that in the treatment condition the mixture was presented on the first trial. Asterisks in graphs (d) and (e) indicate significantly higher SWT on the first water rinse after the mixture compared to the SWT after lactisole alone (Tukey HSD, p<0.05). In graphs <b>(f-j)</b> W/S indicates that in the treatment condition the sweetener was presented on the second trial. Thus in <b>(f-j)</b> the data on the second trial reflects the sweetness evoked by the sweetener, and the remaining 4 trials indicate the SWT. Arrows below the x-axis highlight the large differences in suppression of the SWT during the first water rinse after each sweetener compared to the second water rinse after lactisole alone. The horizontal dotted line in each graph indicates a “barely detectable” level of sweetness. Vertical bars are SEs of the log₁₀ means.</p

Effect of sucrose on the lactisole sweet water taste.

<p>The perceived intensity of sweetness (black circles), saltiness (dark gray circles), sourness (light gray circles), and bitterness (open circles) are shown for the 5 conditions of experiment 1: <b>(a)</b> LAC → H₂O: lactisole followed by 5 water rinses; <b>(b)</b> MIX → H₂O: lactisole + sucrose, followed by 5 water rinses; <b>(c)</b> SUC → LAC: sucrose before lactisole, followed by 4 water rinses; <b>(d)</b> LAC→ SUC: sucrose after lactisole, followed by 4 water rinses; and <b>(e)</b> LAC → H₂O → SUC: sucrose after lactisole and 1 water rinse, followed by 3 water rinses. Letters on the x-axis of each graph represent water rinses (W), lactisole rinses (L), and sucrose rinses (S). Letters on the right y-axes represent semantic labels of sensation intensity on the gLMS: BD = barely detectable; W = weak; M = moderate, and S = strong. The dotted line at BD serves to highlight the near imperceptibility of most tastes other than sweetness, and the number of rinses over which the SWT was clearly perceived. Vertical bars indicate standard errors (SEs) of the log₁₀ means.</p

Pre-exposure to lactisole suppresses the sweetness of sucrose and neotame in ‘still’ solutions.

<p>Shown are log₁₀ ratings of the sweetness of <i>still</i> solutions of sucrose or neotame perceived on the tongue tip when the solutions were sampled alone or following exposure to a <i>still</i> solution of lactisole, in which rinsing of lactisole is assumed to be incomplete and therefor results in partial suppression of sweetness. Different letters over the bars indicate significant differences in sweetness. The dotted line indicates the level of “barely detectable” sweetness. Vertical bars are the SEs of the log₁₀ means.</p

Lactisole sweet water taste requires flowing water rinses.

<p>Shown are log₁₀ ratings of the lactisole SWT experienced on the tongue tip in experiment 3 under conditions of <i>Still</i> vs. <i>Flowing</i> water rinses. The dotted line indicates the level of “barely detectable” sweetness. Vertical bars are the SEs of the log₁₀ means.</p

Decay in sweetness produced by sweeteners alone across water rinses.

<p>Main graph: Peak sweetness ratings for the 5 sweeteners of experiment 2 when presented alone and during 5 water rinses. S and W’s on the x-axis indicate exposures to the sweeteners and water rinses, respectively. The horizontal dotted line indicates a “barely detectable” level of sweetness; vertical bars are SEs of the log₁₀ means. Inset: residual sweetness during the first water rinse expressed as a percentage of the initial sweetness reported for each of the sweeteners.</p

Mass change of the e-liquid after 20 puffs as well as amount of condensate found inside of the mouthpiece, the mass, and resulting concentration (μg/mg) of sucralose found in the trapped vapor and the mouthpiece condensate.

<p>Mass change of the e-liquid after 20 puffs as well as amount of condensate found inside of the mouthpiece, the mass, and resulting concentration (μg/mg) of sucralose found in the trapped vapor and the mouthpiece condensate.</p

Mean ratings of liking/disliking.

<p>Mean ratings of <i>liking/disliking</i> across both e-cig devices for all e-liquids sampled alone (gray bars) and with 1% sucralose (black bars). Olfaction = nose open, No Olfaction = nose closed. The data show that liking differed significantly between olfactory conditions, as seen by higher ratings with the nose open, and across flavors. The letters on the right-y axis represent labels on the Labeled Hedonic Scale (LHS): DM = Dislike Moderately, DS = Dislike Slightly, N = Neutral, LS = Like Slightly, LM = Like Moderately. Vertical bars represent standard errors of the mean.</p

Ratings of overall flavor, sweetness and harshness intensity.

<p>Log₁₀ mean ratings of (A) Overall Flavor, (B) Sweetness and (C) Harshness/Irritation intensity for each e-liquid alone (gray bars) and with 1% sucralose added (black bars). Data from the V2 EX tanks are on the left and the V2 cartridges on the right under 2 vaping conditions: Olfaction = nose open, No Olfaction = nose closed. The data show that in the No Olfaction condition <i>overall flavor</i> and <i>sweetness</i> were significantly attenuated compared to the Olfaction condition for both E-cigarettes, and that sucralose produced significant increases in the same 2 flavor categories only when added to the V2 cartridges. The letters on the right y-axis represent semantic labels of intensity on the general Labeled Magnitude Scale (gLMS): BD = Barely Detectable; W = Weak; M = Moderate; S = Strong. Vertical bars are standard errors of the mean.</p

Shown are the 2 e-cigarette delivery systems that were tested.

<p>The systems (cartridge/cartomizer and tank/clearomizer) are powered by the same battery (left), but differ in the way e-liquids are stored and delivered to the heating element (i.e., in a saturated, rolled cotton/ceramic pad vs. a tank containing a braided cotton/ceramic wick) and in the design and size of the mouthpiece.</p