Leon Kośmider

Compensatory Puffing With Lower Nicotine Concentration E-liquids Increases Carbonyl Exposure in E-cigarette Aerosols

Introduction Article 20 of the European Tobacco Products Directive (EU-TPD) specifies that e-liquids should not contain nicotine in excess of 20 mg/mL, thus many vapers may be compelled to switch to lower concentrations and in so doing, may engage in more intensive puffing. This study aimed to establish whether more intensive puffing produces higher levels of carbonyl compounds in e-cigarette aerosols. Methods Using the HPLC-UV diode array method, four carbonyl compounds (formaldehyde, acetaldehyde, acetone, and acrolein) were measured in liquids and aerosols from nicotine solutions of 24 and 6 mg/mL. Aerosols were generated using a smoking machine configured to replicate puffing topography data previously obtained from 12 experienced e-cigarette users. Results Carbonyl levels in aerosols from the puffing regimen of 6 mg/mL were significantly higher (p < .05 using independent samples t tests) compared with those of 24 mg/mL nicotine. For the 6 and 24 mg/mL nicotine aerosols respectively, means ± SD for formaldehyde levels were 3.41 ± 0.94, and 1.49 ± 0.30 µg per hour (µg/h) of e-cigarette use. Means ± SD for acetaldehyde levels were 2.17 ± 0.36 and 1.04 ± 0.13 µg/h. Means ± SD for acetone levels were 0.73 ± 0.20 and 0.28 ± 0.14 µg/h. Acrolein was not detected. Conclusions Higher levels of carbonyls associated with more intensive puffing suggest that vapers switching to lower nicotine concentrations (either due to the EU-TPD implementation or personal choice), may increase their exposure to these compounds. Based on real human puffing topography data, this study suggests that limiting nicotine concentrations to 20 mg/mL may not result in the desired harm minimalization effect. Implications More intensive puffing regimens associated with the use of low nicotine concentration e-liquids can lead to higher levels of carbonyl generation in the aerosol. Although in need of replication in a larger sample outside a laboratory, this study provides pragmatic empirical data on the potential risks of compensatory puffing behaviors in vapers, and can help to inform future regulatory decisions on nicotine e-liquid concentrations. The cap on nicotine concentration at 20 mg/mL set by the EU-TPD may therefore have the unintended consequence of encouraging use of lower nicotine concentration e-liquid, in turn increasing exposure to carbonyl compounds through compensatory puffing.

Automated fluorescence microscopy image analysis of Pseudomonas aeruginosa bacteria in alive and dead stadium

Abstract Fluorescent microscopy techniques take advantage of observing even single cells in live and dead stadium, and make it possible to selectively recognize specific components of biomolecular structures. This methodology is based on Green Fluorescent Protein (GFP) recognition of biochemical activities of individual microbial cells visible in screening. Unfortunately, recognition perception of human professional for fluorescent signals can be affected by various environmental factors what can lead to false interpretation of the results. Therefore intelligent computer method for fluorescent signal counting can be a great assistance at work. In this article we present experimental research results on the development of new automated fluorescence microscopy image analysis, implemented for Pseudomonas aeruginosa bacteria. Proposed method is composed of two stages of image processing. In the first, we enhance the image and extract only important bacteria shapes into simplified image. In the second, this simplification is used for detection of rod shape and spherical shape bacteria. At the end of processing statistical analysis is performed to evaluate number of bacteria in dead and alive stadium.

Small lung nodules detection based on local variance analysis and probabilistic neural network

BACKGROUND AND OBJECTIVE In medical examinations doctors use various techniques in order to provide to the patients an accurate analysis of their actual state of health. One of the commonly used methodologies is the x-ray screening. This examination very often help to diagnose some diseases of chest organs. The most frequent cause of wrong diagnosis lie in the radiologists difficulty in interpreting the presence of lungs carcinoma in chest X-ray. In such circumstances, an automated approach could be highly advantageous as it provides important help in medical diagnosis. METHODS In this paper we propose a new classification method of the lung carcinomas. This method start with the localization and extraction of the lung nodules by computing, for each pixel of the original image, the local variance obtaining an output image (variance image) with the same size of the original image. In the variance image we find the local maxima and then by using the locations of these maxima in the original image we found the contours of the possible nodules in lung tissues. However after this segmentation stage we find many false nodules. Therefore to discriminate the true ones we use a probabilistic neural network as classifier. RESULTS The performance of our approach is 92% of correct classifications, while the sensitivity is 95% and the specificity is 89.7%. The misclassification errors are due to the fact that network confuses false nodules with the true ones (6%) and true nodules with the false ones (2%). CONCLUSIONS Several researchers have proposed automated algorithms to detect and classify pulmonary nodules but these methods fail to detect low-contrast nodules and have a high computational complexity, in contrast our method is relatively simple but at the same time provides good results and can detect low-contrast nodules. Furthermore, in this paper is presented a new algorithm for training the PNN neural networks that allows to obtain PNNs with many fewer neurons compared to the neural networks obtained by using the training algorithms present in the literature. So considerably lowering the computational burden of the trained network and at same time keeping the same performances.

E-cigarette puffing patterns associated with high and low nicotine e-liquid strength: effects on toxicant and carcinogen exposure

BackgroundContrary to intuition, use of lower strength nicotine e-liquids might not offer reduced health risk if compensatory puffing behaviour occurs. Compensatory puffing (e.g. more frequent, longer puffs) or user behaviour (increasing the wattage) can lead to higher temperatures at which glycerine and propylene glycol (solvents used in e-liquids) undergo decomposition to carbonyl compounds, including the carcinogens formaldehyde and acetaldehyde. This study aims to document puffing patterns and user behaviour associated with using high and low strength nicotine e-liquid and associated toxicant/carcinogen exposure in experienced e-cigarette users (known as vapers herein).Methods/designA counterbalanced repeated measures design. Participants: Non-tobacco smoking vapers; have used an e-cigarette for ≥3 months; currently using nicotine strength e-liquid ≥12mg/mL and a second or third generation device. Intervention: This study will measure puffing patterns in vapers whilst they use high and low strength nicotine e-liquid under fixed and user-defined settings, each for a week. The 4 counterbalanced conditions are: i) low strength (6mg/mL), fixed settings; ii) low strength user-defined settings; iii) high strength (18mg/mL) fixed settings; iv) high strength user-defined settings. Biomarkers of exposure to toxicants and carcinogens will be measured in urine. In the second phase of this study, toxicant yields will be measured in aerosol generated using a smoking machine operated to replicate the puffing behaviours of each participant. Primary outcomes: i) Puffing patterns (mean puff number, puff duration, inter-puff interval and mL of liquid consumed) and user behaviour (changes to device settings: voltage and air-flow) associated with using high and low strength nicotine e-liquid. ii) Toxicant/carcinogen exposure associated with the puffing patterns/device settings used by our participants. Secondary outcomes: i) Subjective effects. ii) comparisons with toxicant exposure from tobacco smoke (using documented evidence) and with recommended safety limits. Sample size: Twenty participants.DiscussionThe findings will have important implications for public health messaging regarding the relative risks and subjective effects associated with using high and low strength nicotine e-liquid, and for policy makers regarding regulations on nicotine concentrations in e-liquids.

Exposure to Cadmium and Lead in Cigarette Smokers Who Switched to Electronic Cigarettes

Introduction E-cigarettes (ECs) seem to be a less harmful alternative for conventional cigarettes. This study aimed to assess whether the generated aerosols from ECs contain lower amount of Cd and Pb than cigarette smoke and to detect any changes in exposure to cadmium and lead among cigarette smokers who switched completely or partially to EC. Methods EC aerosols and cigarette smoke were generated, and the determination of Cd and Pb in trapped samples and e-liquids was performed by the Electrothermal Atomic Absorption Spectrometry (ETAAS) method. A cross-sectional, group-based survey was carried out using 156 volunteers classified into groups of nonsmokers, EC-only users, dual EC users-cigarette smokers and cigarette-only smokers. Using ETAAS, blood Cd and Pb levels were measured, and the results were compared by analysis of covariance. Results Transfer of Cd and Pb to EC aerosol was found to be minimal, although the metals were present in the remaining e-liquid from tanks used for vapor generation. The geometric mean blood cadmium concentration adjusted for age and sex was 0.44 (95% confidence interval: 0.37 to 0.52) µg/L in the EC-only users, which was significantly lower than those in the smokers of 1.44 (1.16 to 1.78) and dual users of 1.38 (1.11 to 1.72). The blood lead geometric mean differed significantly only between nonsmokers of 11.9 (10.6 to 13.3) and smokers of 15.9 (13.6 to 18.6). Conclusion The study revealed that smokers who completely switched to e-cigarettes and quit smoking conventional cigarettes may significantly reduce their exposure to Cd and probably Pb.

E-cigarettes: voltage- and concentration-dependent loss in human lung adenocarcinoma viability: E-cigarette: voltage and concentration decrease cell viability

E‐cigarettes are used by millions of people despite the fact that the harmful effect of aerosol emitted from these products to the human organism is still not clear. In this paper, toxicity of vapor generated using different solutions and battery output voltage on A549 cells viability is presented. The obtained EC50 values for commercially available propylene glycol/glycerol solution 1:1 e‐liquids based on 3.2 V (0.127%), 4.0 V (0.112%) and 4.8 V (0.038%) were about 1.5–4.5 times higher than in tobacco smoke (0.0086%). Furthermore, it was shown that the increase of battery output voltage decreased A549 cell viability. In addition, commercially available extracts were more cytotoxic than laboratory made extracts. Owing to the expansiveness of e‐cigarettes, it is very important to estimate their impact on public health. Our results not only confirm less cytotoxicity of e‐liquid aerosol than cigarette smoke, but also demonstrate that solutions used in e‐liquids and, for the first time, battery output voltage have a significant impact on cytotoxicity of e‐cigarette vapor. Thus, the results of this study are very important for the current and future legal regulations on e‐cigarettes.

'Real-world' compensatory behaviour with low nicotine concentration e-liquid: subjective effects and nicotine, acrolein and formaldehyde exposure.

Abstract Aims To compare the effects of (i) high versus low nicotine concentration e‐liquid, (ii) fixed versus adjustable power and (iii) the interaction between the two on: (a) vaping behaviour, (b) subjective effects, (c) nicotine intake and (d) exposure to acrolein and formaldehyde in e‐cigarette users vaping in their everyday setting. Design Counterbalanced, repeated measures with four conditions: (i) low nicotine (6 mg/ml)/fixed power; (ii) low nicotine/adjustable power; (iii) high nicotine (18 mg/ml)/fixed power; and (iv) high nicotine/adjustable power. Setting London and the South East, England. Participants Twenty experienced e‐cigarette users (recruited between September 2016 and February 2017) vaped ad libitum using an eVic Supreme™ with a ‘Nautilus Aspire’ tank over 4 weeks (1 week per condition). Measurements Puffing patterns [daily puff number (PN), puff duration (PD), interpuff interval (IPI)], ml of e‐liquid consumed, changes to power (where permitted) and subjective effects (urge to vape, nicotine withdrawal symptoms) were measured in each condition. Nicotine intake was measured via salivary cotinine. 3‐Hydroxypropylmercapturic acid (3‐HPMA), a metabolite of the toxicant acrolein, and formate, a metabolite of the carcinogen formaldehyde, were measured in urine. Findings There was a significant nicotine concentration × power interaction for PD (P < 0.01). PD was longer with low nicotine/fixed power compared with (i) high nicotine/fixed power (P < 0.001) and (ii) low nicotine/adjustable power (P < 0.01). PN and liquid consumed were higher in the low versus high nicotine condition (main effect of nicotine, P < 0.05). Urge to vape and withdrawal symptoms were lower, and nicotine intake was higher, in the high nicotine condition (main effects of nicotine: P < 0.01). While acrolein levels did not differ, there was a significant nicotine × power interaction for formaldehyde (P < 0.05). Conclusions Use of a lower nicotine concentration e‐liquid may be associated with compensatory behaviour (e.g. higher number and duration of puffs) and increases in negative affect, urge to vape and formaldehyde exposure.