Single Puff Research Articles

Abstract B017: Kick Vaping: Feasibility, acceptability, and preliminary impact of a vaping cessation text messaging intervention for Latino young adults

Abstract Objective: The purpose of this study was to assess the feasibility, acceptability, and preliminary impact of Kick Vaping among Latino young adults. Methods: Forty Latino young adults (ages 18 to 25) who were currently vaping received Kick Vaping, a vaping cessation text messaging intervention available in English and Spanish. Feasibility was measured by the eligibility rate (defined as the proportion of individuals screened who were eligible), enrollment rate (the proportion of eligible individuals who enrolled), and follow-up rate (the proportion of participants who completed the follow-up assessment at Month 3). Acceptability was measured by overall satisfaction with the intervention and perceived helpfulness. Preliminary impact was measured by self-reported 7-day point prevalence abstinence (not vaping, even a single puff, in the past seven days) and changes in self-efficacy. Results: A total of 203 individuals were identified, 61 completed the eligibility assessment, and 55 were eligible to participate in the study. Forty individuals consented to participate in the study and enrolled in Kick Vaping. The eligibility and enrollment rates were 30.0% (61/203) and 72.7% (40/55), respectively. At baseline, participants’ mean age was 22.3 years old (SD 2.1), 45.0% of participants were female, and 45.0% were heterosexual or straight. Half of the participants had a high school education or less (50.0%) and were currently employed. Fourteen (35.0%) participants reported speaking English and Spanish equally. Most participants used disposable devices (70%), vaped daily (97.5%), had low (37.5%) or medium (35.0%) e-cigarette dependence, and had attempted to quit in the past year (72.5%). At Month 3, the follow-up rate was 90% (36/40). Treating those lost to follow-up as participants who continued vaping, 75% (30/40) of participants self-reported 7-day point prevalence abstinence. Self-efficacy mean scores significantly increased from 30.65 (SD 8.07) at baseline to 50.11 (SD 10.57) at follow-up (p<0.01). Moreover, most participants (88.9%, 32/36) reported being satisfied/extremely satisfied with Kick Vaping. Additionally, most participants (83.3%, 30/36) reported that the intervention included “just the right amount of messages”. Lastly, most participants (86.1%, 31/16) reported that Kick Vaping helped them quit vaping “a lot”. Conclusion: It is feasible to recruit and retain Latino young adults in a vaping cessation text messaging intervention. Moreover, Kick Vaping generated high satisfaction and perceived helpfulness among Latino young adults, significantly increased self-efficacy, and resulted in a notable vaping cessation rate at Month 3. Additional testing in a randomized clinical trial is warranted to assess the efficacy of the intervention. Citation Format: Rafael H. Orfin, Jeffrey Wilmer Ramos Santiago, Ritsel Decena Soriano, Eliany Romero Acosta, Diana Bermudez, Yaneth L. Rodriguez, Dongmei Li, Irfan Rahman, Scott McIntosh, Deborah J. Ossip, Ana Paula Cupertino, Francisco Cartujano-Barrera. Kick Vaping: Feasibility, acceptability, and preliminary impact of a vaping cessation text messaging intervention for Latino young adults [abstract]. In: Proceedings of the 17th AACR Conference on the Science of Cancer Health Disparities in Racial/Ethnic Minorities and the Medically Underserved; 2024 Sep 21-24; Los Angeles, CA. Philadelphia (PA): AACR; Cancer Epidemiol Biomarkers Prev 2024;33(9 Suppl):Abstract nr B017.

Neutron-producing gas puff Z-pinch experiments on a fast, low-impedance, 0.5 MA linear transformer driver

A study on the neutron production from single and double gas puff Z-pinches on the CESZAR linear transformer driver with ∼0.45 MA current and 170 ns rise time is presented. Total neutron yield measurements made with a LaBr activation detector are compared for three configurations, using a double nozzle setup. When a single, hollow, deuterium gas shell was used, reliable implosions could only be attained at higher load mass than the optimal value to match implosion time with the driver rise time, with neutron yields of ∼106 per pulse. The use of a double gas puff configuration with a deuterium center jet allowed a reduction in the shell density and operation closer to machine-matched conditions, recording up to (4.1 ± 0.3) × 107 neutrons/pulse when either Kr or D2 was used in the shell. For a comparable mass and implosion time, using a higher atomic-number gas in the outer shell results in more unstable plasma surface and smaller plasma radius at the location of instability bubbles, which, however, do not seem to consistently correlate with a higher neutron yield. Comparing implosion dynamics with models and neutron yields with literature scaling suggests that the machine current is not well coupled to the plasma during the final stages of compression. Optimizing current and energy coupling to the pinched plasma is critical to improving performance, particularly in low-impedance drivers.

Repellency, toxicity, and physiological actions of low molecular weight basic amines in mosquitoes.

This study investigated the behavioral responses and toxicity of three basic amines: 1-methylpiperazine, 1-methylpyrrolidine, and triethylamine (TEA), compounds suggested previously to be anosmic in vapor exposures to caged mosquitoes. These compounds showed repellency of Aedes aegypti mosquitoes, followed by flightlessness, knockdown, and paralysis, all increasing with exposure time and dosage. Electrophysiological experiments showed a blocking effect on nerve discharge of the Drosophila melanogaster larval central nervous system (CNS) with little evidence of hyperexcitation. Blockage of voltage-gated (Kv2) potassium channel currents under patch clamp occurred at similar concentrations. Involvement of K+ channels in the action of basic amines was supported by behavior and CNS recordings of a Shaker Kv1 mutant exposed to TEA, where instead of blockage, a hyperexcitation of nerve firing was observed. Experiments on cockroach leg mechanoreceptors demonstrated neuronal excitation and on mosquito antennae strong electroantennogram (EAG) signals with an augmentation of blank air responses after a single puff of basic amine. The neurophysiological effects of basic amines are consistent with K+ channel block, whereas the antennal EAG response was not obviously associated with anosmia. The low-dose effects of basic amines appear to be repellency and bradykinesia. Overall, the findings provide key insights into the mechanisms underlying the biological activity of basic amines. © 2024 Society of Chemical Industry.

Comparison of brain nicotine accumulation from traditional combustible cigarettes and electronic cigarettes with different formulations.

Rapid brain accumulation is critical for the acute reinforcing effects of nicotine. Although nicotine formulation (free-base vs. protonated or salt) in electronic cigarette (E-cig) liquid affects user satisfaction, its impact on brain nicotine accumulation (BNA) from E-cig use has not been evaluated in comparison with traditional combustible cigarettes (C-cigs) using a within-subjects design. BNA was directly assessed with 29 adult dual users (13 females) of E-cigs and C-cigs, using [11C]nicotine and positron emission tomography (PET). Participants underwent two 15-min upper body (from chest to head) scanning sessions during which they inhaled a single puff of [11C]nicotine-labeled vapor from E-cigs with free-base nicotine or C-cig smoke in a randomized order. Seventeen of them also went through another session during which they inhaled from E-cigs with nicotine salt. A full-body scan was also conducted at each session to measure total absorbed dose of [11C]nicotine. Mean maximum nicotine concentration (Cmax) in brain following inhalation of free-base nicotine E-cig vapor was 19% and 15% lower relative to C-cig smoke and nicotine salt E-cig vapor (ps = 0.014 and 0.043, respectively). The Cmax values did not differ significantly between the C-cig and nicotine salt E-cig. Mean values of time to the maximum concentration (Tmax) were not significantly different between the two types of E-cig, but they were 64% and 40% longer than that for C-cig smoking (ps = 0.0005 and 0.004, respectively). Mean Cmax with C-cigs and free-base nicotine E-cigs were greater in females relative to males and correlated with T1/2 of lung nicotine clearance and participants' pack-years. These results suggest that while E-cigs with free-base nicotine formulation can deliver nicotine rapidly to the brain, those with nicotine salt formulation are capable of even more efficient brain nicotine delivery closely resembling combustible cigarettes. Therefore, nicotine formulation or pH in E-liquid should be considered in evaluation of E-cigs in terms of abuse liability and potential in substituting for combustible cigarettes.

Making Every Single Puff Count-Simple and Sensitive E-Cigarette Aerosol Sampling for GCxIMS and GC-MS Analysis.

The analysis of the aerosol from tobaccoless electronic cigarettes (e-cigarettes) is an important part of understanding their impact on human health, yet sampling aerosol from e-cigarettes is still considered a challenge. It lacks a standard method for research and quality control and there are a variety of methods. However, few are simple and inexpensive, and none have been suggested for the use with gas chromatography coupled ion mobility spectrometry (GCxIMS). This work presents and evaluates such a setup made from standard lab equipment to quickly collect a quantitative sample from the aerosol of a single puff (5 s totaling 125 mL). The aerosol condensates directly in the cooled headspace (HS) vial, which is analyzed in the HS-GCxIMS or mass spectrometer (HS-GC-MS). The combined use of GC-MS and GCxIMS allows the simple and sensitive identification of unknown substances in complex mixtures and the identification of degradation products in the aerosols. A calibration of 26 flavor compounds (0.2-20 µg/g) was created using single puffs of a spiked, flavorless commercial refill solution and 2-alkanones as internal standards. This sensitive but easily reproducible setup enables a wide range of further investigations, even for labs that were previously unable to afford it.

Usage Pattern and Nicotine Delivery during Ad Libitum Consumption of Pod E-Cigarettes and Heated Tobacco Products.

Many different nicotine delivery products, such as e-cigarettes (e-cigs) or heated tobacco products (HTPs), are available on the market. To better understand these products, it is crucial to learn how consumers use them and how much nicotine they deliver. Therefore, a pod e-cig, an HTP, and a conventional cigarette (CC) were each used by 15 experienced users of the respective product category for 90 min without special use instructions ("ad libitum"). Sessions were video recorded to analyze usage patterns and puff topography. At defined time points, blood was sampled to determine nicotine concentrations, and subjective effects were inquired about using questionnaires. During the study period, the CC and HTP groups averaged the same number of consumption units (both 4.2 units). In the pod e-cig group, the highest number of puffs was taken (pod e-cig 71.9; HTP: 52.2; CC: 42.3 puffs) with the most extended mean puff duration (pod e-cig: 2.8 s; HTP: 1.9 s; CC: 1.8 s). Pod e-cigs were predominantly used with single puffs or in short clusters of 2-5 puffs. The maximum plasma nicotine concentration was highest for CCs, followed by HTPs, and then pod e-cigs with 24.0, 17.7, and 8.0 ng/mL, respectively. Craving was reduced by all products. The results suggest that the high nicotine delivery known for tobacco-containing products (CCs and HTPs) may not be needed for non-tobacco-containing products (pod e-cigs) to satisfy cravings in experienced users.

325 Predictors of Substance Use Initiation by Late Childhood: Findings from the Adolescent Brain Cognitive Development (ABCD) Study

OBJECTIVES/GOALS: Adolescence represents a critical period for substance use initiation. Various factors may contribute to trying a sip or single puff of a substance, that could lead to more frequent use. However, less is known about how predictors from multiple domains converge to impact risk for general substance use initiation. METHODS/STUDY POPULATION: The Adolescent Brain Cognitive Development (ABCD) study is a multi-site longitudinal study following youth into early adulthood. The present study included 7,644 ABCD children who reported no lifetime substance use (including any experimentation) at baseline (ages 9–10). Our primary aim was to use a random forest classification model to predict binary substance use initiation, defined as trying any non-prescribed substance (e.g., alcohol, tobacco, cannabis, non-prescribed medications), during a 2-year follow-up after baseline. A total of 402 variables from the following categories were examined as predictors: demographics, peer substance use and availability, mental and physical health, culture and environment, biospecimens, neurocognitive functioning, and structural neuroimaging variables. RESULTS/ANTICIPATED RESULTS: Over a two-year follow-up, 751 (9.8%) of substance-naïve children reported trying a substance by age 11. The most common substance was alcohol, followed by cannabis and tobacco. Mean Decrease Accuracy (MDA) values were used to assess the relative importance of each predictor. The overall accuracy of the model in accurately predicting group membership (no substance use initiation vs. substance use initiation) was 57.66%. Of the top 5 predictors, the most important predictor was intent to use alcohol (MDA = .002). The following top predictors were structural neuroimaging variables: volume and surface area of right lateral occipital lobe (MDA = .0009 and .0008, respectively), surface area of right inferior temporal lobe (MDA = .0007), and surface area of left superior frontal lobe (MDA = .0007). DISCUSSION/SIGNIFICANCE: A combination of intent to use alcohol and structural neuroimaging indices were among the top predictors of substance use initiation. Understanding predictors of early substance use experimentation is important for identifying at-risk youth that may require targeted intervention approaches.

Effect of Electronic Cigarette Liquid pH on Retention of 11C-Nicotine in a Respiratory Tract Model.

Based on our preliminary 11C-nicotine positron emission tomography (PET) imaging studies in humans, we speculated that greater deposition of nicotine in the respiratory tract from electronic cigarettes compared to combustible cigarettes could result from the alkaline pH of typical aerosol-producing electronic cigarette liquids (e-liquids). To address this hypothesis, we assessed the effect of e-liquid pH on the retention of nicotine in vitro using 11C-nicotine, PET, and a human respiratory tract model of nicotine deposition. A single 2-second 35-mL puff was delivered to a human respiratory tract cast from a 2.8-Ohm cartomizer at 4.1 volts. Immediately after the puff, a 2-second 700-mL air wash-in volume was administered. E-liquids (glycerol and propylene glycol 50/50 vol/vol) containing 24 mg/mL nicotine were mixed with 11C-nicotine. Deposition (retention) of nicotine was assessed using a GE Discovery MI DR PET/CT scanner. Eight e-liquids with different pH values (range 5.3-9.6) were investigated. All experiments were performed at room temperature and at a relative humidity of 70%-80%. Retention of nicotine in the respiratory tract cast was pH dependent and the pH-sensitive component of the retention was well described by a sigmoid curve. In total, 50% of the maximal pH-dependent effect was observed at pH 8.0, which is close to the pKa2 of nicotine. The retention of nicotine in the respiratory tract conducting airways is dependent on the e-liquid pH. Lowering the e-liquid pH reduces retention of nicotine. Nonetheless, reduction of the pH below 7 has little effect, consistent with the pKa2 of protonated nicotine. Similar to combustible cigarettes, the retention of nicotine in the human respiratory tract from consumption of electronic cigarettes may have some health consequences and affect nicotine dependence. Here we demonstrated that the retention of nicotine in the respiratory tract is dependent on the e-liquid pH, and lowering pH reduces retention of nicotine in conducting airways of the respiratory tract. Therefore, e-cigarettes with low pH values would result in reduced respiratory tract nicotine exposure and faster delivery of nicotine to the central nervous system (CNS). The latter can be associated with e-cigarette abuse liability and the effectiveness of e-cigarettes as substitutes for combustible cigarettes.

The versatile fueling systems of WEST

New fueling systems have been designed for WEST, a full tungsten wall tokamak with divertor configuration. They consist of standard gas injection, supersonic molecular beam injection and pellets injection systems, each being able to fuel continuously the plasma discharge up to a duration of 1000s. A massive gas injection system is also implemented to mitigate the impact of disruptions and runaway electrons. The standard gas system consists of 4 independent lines allowing the injection of up to 4 different gas species during a plasma discharge through 11 injections areas, 4 of them being located in the divertors and in the private flux region. The pellet injection system is able to inject up to 10 pellets per second through 4 tracks: one on the low field side, and the other 3 on the high field side. The supersonic molecular beam injection system consists of 3 injectors located close to the midplane, two on the high field side and one on the low field side. On trigger, the massive gas injection system can deliver in a single puff up 800 Pa.m3 of noble gas in order to stop the plasma discharge. All the fueling systems have been characterized and can be used routinely on plasma.

Characterizing different-flavored e-cigarette solutions from user-reported sensory attributes and appeal.

Scientists and regulators need parsimonious methods of characterizing flavored e-cigarettes which may vary widely in both chemical flavoring constituents and marketing descriptors. This laboratory experiment characterized user-reported appeal and experience of five cross-cutting sensory attributes (sweetness, bitterness, smoothness, harshness, coolness) of 10 common e-cigarette flavors. In a within-subject double-blind single-visit protocol, current nicotine/tobacco product users (N = 119) self-administered a single puff of each e-liquid flavor via a pod-style device and rated its appeal and sensory attributes on 0-100 scales. Custom-manufactured e-liquids, nicotine concentration: M (SD) = 23.4 (0.9) mg/mL, representative of commonly marketed fruit (green apple, strawberry), dessert (dark chocolate, vanilla), mint (peppermint, spearmint), nonmint cooling (menthol, koolada), and tobacco (subtle tobacco, full-flavored tobacco) flavor descriptors were used and their constituents were independently analyzed. Results largely demonstrated that a flavor's sensory attributes concorded with its marketed flavor descriptor. Among the 10 flavors, vanilla was rated sweetest (B[difference vs. mean of 9 other flavors] = 14.44, 95% CI [10.84, 18.03]), full-flavored tobacco was most bitter, B = 8.34, 95% CI [4.73, 11.96], subtle tobacco was most harsh, B = 5.69, 95% CI [1.70, 9.68], and peppermint scored highest in both smoothness, B = 6.98, 95% CI [3.13, 10.82], and coolness, B = 29.25, 95% CI [25.50, 33.01]. Flavors with higher appeal ratings tended to be sweeter, smoother, cooler, and less bitter and harsh. Chemical analysis found numerous flavoring constituents among study products without any clear differentiation of chemicals being present in particular flavor categories, which underscores the utility of using sensory ratings to characterize different-flavored e-cigarettes over and above constituent analyses. Characterizing e-cigarette flavors by subjective sensory attributes may be useful in future research and regulatory activities. (PsycInfo Database Record (c) 2022 APA, all rights reserved).

Mechanism for turbulence proliferation in subcritical flows

The subcritical transition to turbulence, as occurs in pipe flow, is believed to generically be a phase transition in the directed percolation universality class. At its heart is a balance between the decay rate and proliferation rate of localized turbulent structures, called puffs in pipe flow. Here, we propose the first-ever dynamical mechanism for puff proliferation—the process by which a puff splits into two. In the first stage of our mechanism, a puff expands into a slug. In the second stage, a laminar gap is formed within the turbulent core. The notion of a split-edge state, mediating the transition from a single puff to a two-puff state, is introduced and its form is predicted. The role of fluctuations in the two stages of the transition, and how splits could be suppressed with increasing Reynolds number, are discussed. Using numerical simulations, the mechanism is validated within the stochastic Barkley model. Concrete predictions to test the proposed mechanism in pipe and other wall-bounded flows, and implications for the universality of the directed percolation picture, are discussed.

Ventilation through a single port

This is a fundamental study of the periodic in & out flow through a single orifice into an enclosure. The purpose of the ‘breathing’ flow is to refresh the enclosure air. The injected air differs from the original enclosure air with respect to concentration of undesirable components or temperature. Two scenarios are considered. (i) Single puff of fresh air injected during an interval t1, followed by a pause t0, and extraction of mixed enclosure air during a second time interval t1. It is shown that the time-averaged rate of enclosure air replacement is maximum when the rhythm is such that t0 ~ t1. (ii) Fresh air injected as a turbulent jet of duration t1, and withdrawal of mixed air during another interval, t2. It is found that the spent power averaged during the cycle is minimum when t1/t2 ~ 1. The concentration of fresh air in the enclosure increases in S-curve fashion, slow-fast-slow. The time scale of the fast (viral) portion of the S curve increases with the length scale of the enclosure and decreases with the Reynolds number based on port diameter and flow velocity. Numerical simulations of the flow confirm several features of the regimes documented theoretically.

Comparison of brain nicotine uptake from electronic cigarettes and combustible cigarettes.

Brain accumulation rate and magnitude are critical for the acute reinforcing effects of nicotine. Despite electronic cigarettes' (E-cigs) appeal as substitutes for traditional combustible cigarettes (C-cigs), brain nicotine accumulation (BNA) from E-cigs has not been compared with that from C-cigs using a within-subjects design. BNA was directly assessed with 16 adult dual users (10 females) of E-cigs (e-liquid pH 9.4) and C-cigs, using 11C-nicotine and positron emission tomography (PET). Participants went through two 15-min head scanning sessions during which they inhaled a single puff of E-cig vapor or C-cig smoke containing 11C-nicotine in a randomized order. A full-body scan was also conducted at each session to measure total absorbed dose of 11C-nicotine. Mean maximum concentration (Cmax) and area under curve of BNA were 22.1% and 22.7% lower, respectively, following E-cig compared with C-cig inhalation. Meanwhile, T1/2 was 2.7 times longer following inhalation of E-cig vapor relative to C-cig smoke (all ps < 0.005). Whole-body imaging indicated greater nicotine retention in the respiratory tract from vapor versus smoke inhalation (p < 0.0001). Following vapor inhalation, nicotine retention in the respiratory tract was correlated with Cmax values of BNA (rs = -0.59, p < 0.02). Our results confirm that E-cigs with alkaline pH e-liquid can deliver nicotine rapidly to the brain, albeit less efficiently than C-cigs partly due to greater airway retention of nicotine. Since brain nicotine uptake mediates reinforcement, these results help elucidate actions of E-cigs in terms of abuse liability and effectiveness in substituting for combustible cigarettes.

Characterization of a rapid condensate collection apparatus for in vitro assays of electronic nicotine delivery systems

In vitro testing of Electronic Nicotine Delivery System (ENDS) aerosol condensates is important in evaluating their potential toxicity. Collecting sufficient condensate for these tests is a time consuming and costly procedure. The “triple puff (TP)” is a novel system which collects the aerosol from three ENDS devices sequentially into a single filter pad and impinger. The TP substantially reduces condensate collection time relative to the conventional single ENDS, single puff (SP), device system. Both the TP and SP (using two puffing profiles) were used to generate condensates from JUUL ENDS e-liquid Mint 5.0% (nicotine by weight). Aerosols were collected using the filter pad and ethanol-containing impinger method. Condensates produced with the SP and TP were compared for concentrations of primary constituents and carbonyl compounds as well as for their cytotoxicity (OECD 129), mutagenicity (OECD 471) and genotoxicity (OECD 487). Condensates generated with the SP and TP, regardless of puffing regimen, were very similar chemically and equivalent in the biological assays tested (not cytotoxic, mutagenic, or genotoxic). The TP device significantly reduces production time of ENDS condensates relative to the standard SP method and thus may facilitate further research by reducing the time and effort required to collect ENDS condensates.

Differences in Acellular Reactive Oxygen Species (ROS) Generation by E-Cigarettes Containing Synthetic Nicotine and Tobacco-Derived Nicotine

Electronic nicotine delivery systems (ENDS) containing synthetic nicotine have yet to be classified as tobacco products; consequently, there is ambiguity over whether Food and Drug Administration (FDA) regulatory authority can be extended to include tobacco-free nicotine (TFN) e-cigarettes. In recent years, a more significant number of e-cigarette companies have been manufacturing TFN-containing e-cigarettes and e-liquids to circumvent FDA regulations. While studies have shown that aerosols generated from tobacco-derived nicotine-containing e-cigarettes contain significant reactive oxygen species (ROS) levels, no comparison studies have been conducted using TFN e-cigarettes. This study uses a single puff aerosol generator to aerosolize TFN and tobacco-derived nicotine-containing vape products and subsequently involves semi-quantifying the ROS generated by these vape products in H2O2 equivalents. We found that the differences between ROS levels generated from TFN and tobacco-derived nicotine-containing vape products vary by flavor. TFN tobacco flavored and fruit flavored products are more toxic in terms of ROS generation than menthol/ice and drink/beverage flavored products using TFN. Our study provides further insight into understanding how flavoring agents used in vape products impact ROS generation from e-cigarettes differently in TFN e-cigarettes than e-cigarettes using tobacco-derived nicotine.

Development of an MRI-Compatible Nasal Drug Delivery Method for Probing Nicotine Addiction Dynamics.

Substance abuse is a fundamentally dynamic disease, characterized by repeated oscillation between craving, drug self-administration, reward, and satiety. To model nicotine addiction as a control system, a magnetic resonance imaging (MRI)-compatible nicotine delivery system is needed to elicit cyclical cravings. Using a concentric nebulizer, inserted into one nostril, we delivered each dose equivalent to a single cigarette puff by a syringe pump. A control mechanism permits dual modes: one delivers puffs on a fixed interval programmed by researchers; with the other, subjects press a button to self-administer each nicotine dose. We tested the viability of this delivery method for studying the brain’s response to nicotine addiction in three steps. First, we established the pharmacokinetics of nicotine delivery, using a dosing scheme designed to gradually achieve saturation. Second, we lengthened the time between microdoses to elicit craving cycles, using both fixed-interval and subject-driven behavior. Finally, we demonstrate a potential application of our device by showing that a fixed-interval protocol can reliably identify neuromodulatory targets for pharmacotherapy or brain stimulation. Our MRI-compatible nasal delivery method enables the measurement of neural circuit responses to drug doses on a single-subject level, allowing the development of data-driven predictive models to quantify individual dysregulations of the reward control circuit causing addiction.

Comparative Reactive Oxygen Species (ROS) Content among Various Flavored Disposable Vape Bars, including Cool (Iced) Flavored Bars.

Studies have shown that aerosols generated from flavored e-cigarettes contain Reactive Oxygen Species (ROS), promoting oxidative stress-induced damage within pulmonary cells. Our lab investigated the ROS content of e-cigarette vapor generated from disposable flavored e-cigarettes (vape bars) with and without nicotine. Specifically, we analyzed vape bars belonging to multiple flavor categories (Tobacco, Minty Fruit, Fruity, Minty/Cool (Iced), Desserts, and Drinks/Beverages) manufactured by various vendors and of different nicotine concentrations (0–6.8%). Aerosols from these vape bars were generated via a single puff aerosol generator; these aerosols were then individually bubbled through a fluorogenic solution to semi-quantify ROS generated by these bars in H2O2 equivalents. We compared the ROS levels generated by each vape bar as an indirect determinant of their potential to induce oxidative stress. Our results showed that ROS concentration (μM) within aerosols produced from these vape bars varied significantly among different flavored vape bars and identically flavored vape bars with varying nicotine concentrations. Furthermore, our results suggest that flavoring chemicals and nicotine play a differential role in generating ROS production in vape bar aerosols. Our study provides insight into the differential health effects of flavored vape bars, in particular cool (iced) flavors, and the need for their regulation.

Heterogeneity of emergency treatment practices in wheezing preschool children.

Our aim was to survey treatment practices used for preschool children with wheezing in emergency rooms (ER) focussing on inhalation device choice and handling, face mask use, salbutamol dosing and written instructions. We sought to assess whether current protocols are in line with published evidence and guidelines. This is a cross-sectional survey done in paediatric ER units located in Finnish municipalities with more than 10000 inhabitants. Of the 100 units contacted, 50% responded. More than 50% of the units used nebulisers. Only 13% of the units administered salbutamol in single puffs. More than 30% of the units lacked criteria on face mask use. Poor co-operation had no effect on the dose of salbutamol in 62% of the units. Ensuring tight mask-to-face seal was included in the training in 20% of the units. A written action plan was provided to the caregivers in 28% of the units. ER treatment guidelines for preschool children with wheezing are poorly endorsed. Research is needed to identify approaches to guideline implementation that are specific for primary care. Clinical research should focus on strengthening recommendations that are currently not embraced. ER treatment protocols need to be updated and adherence to guidelines should be re-evaluated.

A Rapid and Sensitive Chemical Screening Method for E-Cigarette Aerosols Based on Runtime Cavity Ringdown Spectroscopy

Growing demand of Juul and other electronic cigarettes, despite critical knowledge gaps about their chemical composition, has led to concerns regarding their potential health effects. We introduce a novel analytical approach, runtime cavity ringdown spectroscopy (rtCRDS) for rapid detection of oxidative products in e-cigarette aerosols, to facilitate the study of aerosol from a single puff of e-liquid. We report a systematic investigation of three flavors of commercial Juul pods (Virginia tobacco, mango, and menthol) and known commercial e-liquid ingredients (propylene glycol (PG), vegetable glycerin (VG), nicotine, ethyl maltol, benzoic acid, and nicotine benzoate) vaped using Juul devices. Juul e-liquids and neat chemical additives spiked into a 30:70 PG/VG solution were vaped and their aerosols were collected in 1-L Tedlar gas bags and analyzed using rtCRDS. Acetaldehyde, formaldehyde, and acetone were identified as primary oxidative products in aerosolized PG/VG. Ethanol was detected as a major constituent of the three commercial Juul flavors. Spectral intensities of carbonyl compounds increased with the addition of spikes, benzoic acid, ethyl maltol, and nicotine to PG/VG, suggesting that oxidative product generation increases with common additives. The method of direct, rapid analysis of e-cig aerosols introduced here can be used to complement traditional methods in vaping exposures.

A numerical study on capillary-evaporation behavior of porous wick in electronic cigarettes

A mathematical model based on heat and mass transfer processes in the porous wick of electronic cigarettes was established to describe the atomization of e-liquids according to max liquid temperature, vaporization rate and thermal efficiency in a single puff. Dominant capillary-evaporation effects were defined in the model to account for the effects of electrical power, e-liquid composition and porosity of the wick material on atomization and energy transmission processes. Liquid temperature, vaporization rate, and thermal efficiency were predicted using the mathematical model in 64 groups, varying with electrical power, e-liquid composition and wick porosity. Experimental studies were carried out using a scaled-model test bench to validate the model’s prediction. A higher PG/VG ratio in the e-liquid promoted energy transfer for vaporization, and the e-liquid temperature was comparatively reduced at a relatively high power, which was helpful to avoid atomizer overheating. Compared with the other factors, wick porosity affected the thermal efficiency more significantly. The vaporization rate increased with a higher wick porosity in a certain range. The modelling results suggested that a greater wick porosity and a higher PG ratio in e-liquids helped to improve the overall thermal efficiency.