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Electronic cigarettes (ECIGs) are appealing in part because of the many flavors of the liquids used in them. Concerns have been raised that some ECIG liquid flavors, especially those that are sweet, are attracting otherwise nicotine-naïve youth to ECIGs. Sucralose is an artificial, non-caloric sweetener that is added to some ECIG liquids. In this study, we evaluated the toxicants, namely isomers of chloropropanols that can be produced when sucralose-containing ECIG liquid is aerosolized. An analytical separation method relying on solid-phase extraction (SPE) to isolate chloropropanols from the propylene glycol/glycerol matrix was developed. Chloropropanols were then derivatized by silylation before they were analyzed on GC-MS. The influence of different ECIG operating conditions on the generation of chloropropanols was studied by varying ECIG device design and power output and also the sucralose concentration of the liquid. Heated sucralose-containing ECIG liquids produce two toxic compounds that can be found in the resulting aerosols. The two chloropropanols, 3-monochloro-1,2-propanediol (3-MCPD), and 1,3-dichloropropanol (1,3-DCP) that were detected under all conditions were found to be correlated significantly with liquid sucralose content. Effective regulation of ECIGs will minimize user and bystander exposure to these and other ECIG toxicants. Copyright © 2019 American Association for Aerosol Research [ABSTRACT FROM AUTHOR]

Popularity of electronic cigarettes (ECIGs) has increased tremendously among young people, in part due to flavoring additives in ECIG liquids. Pyrazines are an important class of these additives, and their presence in tobacco cigarettes has been correlated with increased acceptability of smoking among smokers and bystanders. Pyrazine use by the tobacco industry is therefore thought to encourage smoking. However, the extent of transfer of pyrazines present in the liquid to aerosols upon vaping remains unclear. We present a simple analytical method to quantify six pyrazine derivatives in liquids and aerosols of ECIGs that allows the isolation of pyrazines from interfering compounds, like nicotine. Standard pyrazine solutions and commercial ECIG samples of different brands and flavors were tested for their pyrazine content in the liquids and in the generated aerosols from these solutions. Testing on ECIG commercial liquids revealed a heterogeneous distribution in the levels and types of pyrazines, with acetyl and alkyl pyrazines present in more than 70% of the samples. This method confirmed that pyrazine additives are common in ECIG and that labels do not usually reflect the type and quantity of pyrazines in the liquid. Pyrazines were not correlated with the nicotine content or the brand of the liquid. The aerosols showed similar pyrazine profiles to their corresponding liquids. The efficiency of transfer of pyrazines into the particle phase was approximately 46%. Therefore, addition of pyrazines to ECIGs should be regulated, because they act synergistically with nicotine to increase product appeal, ease smoking initiation, and discourage cessation. [ABSTRACT FROM AUTHOR]

Electronic cigarettes (ECIGs) heat and vaporize a liquid mixture to produce an inhalable aerosol that can deliver nicotine to the user. The liquid mixture is typically composed of propylene glycol (PG) and vegetable glycerin (VG), in which are dissolved trace quantities of flavorants and, usually, nicotine. Due to their different chemical and thermodynamic properties, the proportions of PG and VG in the liquid solution may affect nicotine delivery and user sensory experience. In social media and popular culture, greater PG fraction is associated with greater “throat-hit,” a sensation that has been attributed in cigarette smokers to increased presence of vapor-phase nicotine. VG, on the other hand, is associated with thicker and larger exhaled “clouds.” In this study, we aim to investigate how PG/VG ratio influences variables that relate to nicotine delivery and plume visibility. Aerosols from varying PG/VG liquids were generated using a digitally controlled vaping instrument and a commercially available ECIG, and analyzed for nicotine content by GC-MS. Particle mass and number distribution were determined using a six-stage cascade impactor and a fast particle spectrometer (TSI EEPS), with tightly controlled dilution and sampling biases. A Mie theory model was used to compute the aerosol scattering coefficients in the visible spectrum. Decreasing the PG/VG ratio resulted in a decrease in total particulate matter (TPM) and nicotine yield (R2> 0.9,p< .0001). Measured particle count median diameter ranged between 44 and 97nm, and was significantly smaller for PG liquids. Although the particle mass concentration was lower, aerosols produced using liquids that contained VG had an order of magnitude greater light scattering coefficients. These findings indicate that PG/VG ratio is a strong determinant of both nicotine delivery and user sensory experience. Copyright © 2017 American Association for Aerosol Research [ABSTRACT FROM AUTHOR]

Electronic cigarettes (ECIGs) electrically heat and aerosolize a liquid-containing propylene glycol (PG), vegetable glycerin (VG), flavorants, water, and nicotine. ECIG effects and proposed methods to regulate them are controversial. One regulatory focal point involves nicotine emissions. We describe a mathematical model that predicts ECIG nicotine emissions. The model computes the vaporization rate of individual species by numerically solving the unsteady species and energy conservation equations. To validate model predictions, yields of nicotine, total particulate matter, PG, and VG were measured while manipulating puff topography, electrical power, and liquid composition across 100 conditions. Nicotine flux, the rate at which nicotine is emitted per unit time, was the primary outcome. Across conditions, the measured and computed nicotine flux were highly correlated (r = 0.85,p< .0001). As predicted, device power, nicotine concentration, PG/VG ratio, and puff duration influenced nicotine flux (p< .05), while water content and puff velocity did not. Additional empirical investigation revealed that PG/VG liquids act as ideal solutions, that liquid vaporization accounts for more than 95% of ECIG aerosol mass emissions, and that as device power increases the aerosol composition shifts towards the less volatile components of the parent liquid. To the extent that ECIG regulations focus on nicotine emissions, mathematical models like this one can be used to predict ECIG nicotine emissions and to test the effects of proposed regulation of factors that influence nicotine flux. Copyright © 2017 American Association for Aerosol Research [ABSTRACT FROM AUTHOR]

Particle size distribution at major on-road, roadside, and university-ground sites in Lebanon were studied in summer 2011. In a predominant old traffic fleet, it is shown that calculated PM2.5 mass emission factors (EFs) conform to those of heavy duty vehicles. When compared to roads in California, higher PM2.5 mass but similar particle number EFs are obtained for the average fleet of the on-road sites. This confirms the observed particle size distribution pattern, rich in particles in the accumulation range mainly between 0.425 and 0.675 µm with a prevalent peak at 0.475 µm. Corresponding total particle counts (TC) measured on the roadside are as high as 14,050 particles/cm3and are up to 67% higher than particle counts measured at the university-ground site. In a hot, dry and humid summer weather with consistent temperature oscillations, particle dispersion is shown to be a function of meteorological factors, mainly the effect of the boundary-layer thickness, with particle counts measured during the morning being around 40% higher than particle counts measured during the afternoon. [ABSTRACT FROM AUTHOR]

Inflammatory processes are characterized by the stimulation of humoral and cellular mediator systems resulting in increased levels of mediators of inflammation such as interleukins (ILs) and prostaglandins (PGs), which play central roles in regulating the inflammatory response and inflammation-mediated damage. The aim of the study was to develop natural therapeutics for the interventions and/or prevention of inflammatory disorders. A methanol plant extract of Centaurea ainetensis Boiss. (Asteraceae) was tested for its anti-inflammatory potential activity in two cell models of inflammation, which served as the basis for the bio-guided fractionation of the extract and the identification of its active ingredient salograviolide A. The guaianolide salograviolide inhibited endotoxin (ET)-induced IL-6 levels in SCp2 mammary epithelial cells and decreased the levels of IL-1-induced cyclooxygenase enzyme levels in intestinal epithelial cells. The results provide evidence for the anti-inflammatory activities of the sesquiterpene agent salograviolide A and the biochemical basis for further studies on salograviolide A mechanism of action. [ABSTRACT FROM AUTHOR]

The susceptibility of 14 human isolates of Candida albicans to commercially available vaginal douche materials and to the essential oil of Origanum syriacum was investigated in hamsters. The essential oil of O. syriacum reduced the colonization and adaptability of the C. albicans more than the commercial douche materials (p < 0.05). In addition, a dilution of the Origanum syriacum essential oil in a water solution of dimethyl sulfoxide resulted in complete elimination of C. albicans from hamster's vagina in comparison to untreated controls (p < 0.05). [ABSTRACT FROM AUTHOR]

The variation in composition of the essential oils produced from different ratios of needles to terminal twigs of Pinus brutia Ten. in Lebanon was examined by GC and GC/MS. As the mass of the needles increased from 0-100% with respect to twig contents, the % oil yield decreased and the composition changed. Pure needle oil was found to be much richer in oxygenated compounds than that of pure twig oil with a corresponding reduction in amounts of monoterpene hydrocarbons. Marker compounds were chosen in order to show the chemical variation of the oils with respect to different ratio of needles to twigs distilled. By computing both physical and chemical variations, it is suggested that a fair compromise between the yield and the concentration of oxygenated compounds is the 75% needle 25% twig mixture, which appears to be the most suitable proportion of plant material for pine oil production from P. brutia. [ABSTRACT FROM AUTHOR]

Essential oils isolated from the aerial parts of two different Lebanese wild populations of Dittrichia graveolens were analyzed by GC and GC/MS. It was shown that around 90% of the total composition consisted of oxygenated compounds. The four major components identified were bornyl acetate (70.6-72.3%), T-cadinol (1.4-13.4%), borneol 2.7-12.4%), and caryophyllene oxide (1.9-2.3%), in addition to 21 minor ones. Oils from the two populations possessed a high content of bornyl acetate but differed with respect to borneol and T-cadinol. In comparison with oils of D. graveolens from other populations, it was found that the oil of D. graveolens of Lebanese origin was distinctly richer in oxygenated compounds. [ABSTRACT FROM AUTHOR]