SignificanceThe wide availability of sweet flavours has been hypothesised as a factor in the popularity of electronic cigarette (ECIG), especially among youth. Saccharides, which are commonly used to ...impart a sweet flavour to ECIG liquids, thermally degrade to produce toxic compounds, like aldehydes and furans. This study investigates the formation of furanic compounds in aerosols when ECIG liquid solutions of varying sweetener concentrations are vaped under different power and puff duration.MethodsLiquids are prepared by mixing aqueous sucrose, glucose or sorbitol solutions to a 70/30 propylene glycol/glycerin solution. Aerosols are generated and trapped on filter pads using a commercially available ECIG operating at 4.3 and 10.8 W and 4 and 8 s puff duration. Extraction, elimination of matrix interference and quantification are achieved using novel solid phase extraction and gas chromatography tandem mass spectrometry methods (GC-MS).ResultsWell-resolved GC peaks of 5-hydroxymethylfurfural (HMF) and furfural (FA) are detected. Both HMF and FA are quantified in the aerosols of sweet-flavoured e-liquids under various vaping conditions. Levels of furan emissions are significantly correlated with electric power and sweetener concentration and not with puff duration. Unlike saccharides, the formation of HMF and FA from a sugar alcohol is negligible.ConclusionsThe addition of sweeteners to ECIG liquids exposes ECIG user to furans, a toxic class of compounds. Under certain conditions, the per-puff yield of HMF and FA in ECIG emissions is comparable to values reported for combustible cigarettes.
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BFBNIB, CEKLJ, CMK, NMLJ, NUK, PNG, SAZU, UL, UM, UPUK
In Lebanon, previous studies have indicated an onset of cardiovascular diseases 12 years earlier than in other parts of the world, suggesting the presence of additional risk factors specific to ...Lebanon. Measurements of airborne particles in Lebanon surpass the recommendations of the World Health Organization by over 150%. This study examined the association between obstructive coronary artery disease (CAD), assessed by a novel marker calculated from coronary catheterization, and markers of air pollution, specifically polycyclic aromatic hydrocarbons (PAHs), in a cohort of 258 patients seen at the American University of Beirut Medical Center since 2014. The concentrations of four types of hydroxylated polycyclic aromatic hydrocarbons (OHPAHs), 2-OHNAP, 2-OHFLU, 3-OHPHE, and 1-OHPYR, were measured in the urine samples of these patients using high performance liquid chromatography coupled with fluorescence detector. Results showed that the OHPAH concentrations were higher than what was reported in high-income countries and, most notably, the levels for non-smokers in this study were higher than those of smokers and some occupational workers in other countries. This implies that patients were exposed to high levels of PAHs, which originate from combustion sources. In particular, 1-OHPYR showed a significant association with presence of obstructive CAD, even after adjusting for covariates like age, sex, and diabetes. Smokers or not, this association has implications for public health and calls for urgent need to pass regulations to reduce the emissions of PAH sources, such as cars, diesel generators, and incinerators.
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•Urinary OHPAH levels were associated with coronary artery disease (CAD) status.•High OHPAH concentrations were attributed to exposure to several combustion sources.•Subjects from Lebanon, even if non-smokers, were highly exposed to PAHs.•1-OHPYR was associated with presence of obstructive CAD.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UILJ, UL, UM, UPCLJ, UPUK, ZAGLJ, ZRSKP
Several sesquiterpene lactones (STLs) have been tested as lead drugs in cancer clinical trials. Salograviolide-
(Sal-
and salograviolide-
(Sal-
are two STLs that have been isolated from
an indigenous ...medicinal plant of the Middle Eastern region. The parent compounds Sal-
and Sal-
were modified and successfully prepared into eight novel guaianolide-type STLs (compounds
-
) bearing ester groups of different geometries. Sal-
, Sal-
, and compounds
-
were tested against a human colorectal cancer cell line model with differing p53 status; HCT116 with wild-type p53 and HCT116 p53
null for p53, and the normal-like human colon mucosa cells with wild-type p53, NCM460. IC
values indicated that derivatization of Sal-
and Sal-
resulted in potentiation of HCT116 cell growth inhibition by 97% and 66%, respectively. The effects of the different molecules on cancer cell growth were independent of p53 status. Interestingly, the derivatization of Sal-
and Sal-
molecules enhanced their anti-growth properties versus 5-Fluorouracil (5-FU), which is the drug of choice in colorectal cancer. Structure-activity analysis revealed that the enhanced molecule potencies were mainly attributed to the position and number of the hydroxy groups, the lipophilicity, and the superiority of ester groups over hydroxy substituents in terms of their branching and chain lengths. The favorable cytotoxicity and selectivity of the potent molecules, to cancer cells versus their normal counterparts, pointed them out as promising leads for anti-cancer drug design.
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IZUM, KILJ, NUK, PILJ, PNG, SAZU, UL, UM, UPUK
In late 2019, hundreds of users of electronic products that aerosolize a liquid for inhalation were hospitalized with a variety of respiratory and gastrointestinal symptoms. While some investigations ...have attributed the disease to the presence of vitamin E acetate in liquids that also contained tetrahydrocannabinol, some evidence suggests that chronic inhalation of two common solvents used in electronic nicotine delivery systems (ENDS), propylene glycol (PG) and vegetable glycerin (VG), can interfere with the lipid components of pulmonary surfactant and cause or exacerbate pulmonary injury. The interaction between PG, VG, and lung surfactant is not yet understood. This study presents an examination of the molecular interactions of PG and VG with lung surfactant mimicked by 1,2-dipalmitoyl-sn-glycero-3-phosphocholine (DPPC). The interaction of DPPC and PG-VG is studied by attenuated total reflectance fourier transform infrared spectroscopy. The results showed that PG and VG altered the molecular alignment of the DPPC surfactant. The orientation of the surfactant at the surface of the lung affects the surface tension at the air–water interface, thereby influencing breathing. These findings suggest that chronic aerosolization of the primary solvents in ENDS might alter the function of pulmonary surfactant.
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IJS, KILJ, NUK, PNG, UL, UM
Accurate and reliable measurements of exposure to tobacco products are essential for identifying and confirming patterns of tobacco product use and for assessing their potential biological effects in ...both human populations and experimental systems. Due to the introduction of new tobacco-derived products and the development of novel ways to modify and use conventional tobacco products, precise and specific assessments of exposure to tobacco are now more important than ever. Biomarkers that were developed and validated to measure exposure to cigarettes are being evaluated to assess their use for measuring exposure to these new products. Here, we review current methods for measuring exposure to new and emerging tobacco products, such as electronic cigarettes, little cigars, water pipes, and cigarillos. Rigorously validated biomarkers specific to these new products have not yet been identified. Here, we discuss the strengths and limitations of current approaches, including whether they provide reliable exposure estimates for new and emerging products. We provide specific guidance for choosing practical and economical biomarkers for different study designs and experimental conditions. Our goal is to help both new and experienced investigators measure exposure to tobacco products accurately and avoid common experimental errors. With the identification of the capacity gaps in biomarker research on new and emerging tobacco products, we hope to provide researchers, policymakers, and funding agencies with a clear action plan for conducting and promoting research on the patterns of use and health effects of these products.
To characterize road-traffic emissions in the greater Beirut area, size-resolved PM10–2.5, PM2.5–0.25 and PM0.25 samples were concurrently collected at near-freeway and background sites. While ...particle mass levels were 1.3–2.6 times greater at the roadside than background location, PM10–2.5 and PM0.25 prevailed at both sites (36–43% of PM10). A chemical mass closure showed that PM10–2.5 was mostly composed of crustal material, contributing to 12–23% of its mass across sites. On the other hand, in PM2.5–0.25 and PM0.25, organic matter (46–56%) was dominant at the roadside location, while secondary ions (SI, 54–68%) were more abundant at the background site. In the vicinity of the freeway, organic carbon (OC) levels varied from 4 μg m−3 in PM10–2.5 to 10.1 μg m−3 in PM0.25, exceeding those at the background site by 4–7 times. In contrast, OC was largely water-soluble at the background location, with its water-soluble fraction displaying comparable PM2.5–0.25- and PM0.25-concentrations at both sites, corroborating its regional secondary origin. PM0.25-elemental carbon (EC), which dominated overall EC mass, was 7-fold greater at the near-freeway than background location, indicating a contribution from diesel or also smoking vehicles to road-traffic emissions. PM2.5-SI showed fairly uniform concentrations across sites, confirming their mainly regional source. Polycyclic aromatic hydrocarbons (PAHs) were undetected at the coastal background site, whereas their levels peaked at 11.5 ng m−3 in proximity to the freeway, with the majority confined to PM0.25. Compared to other roadways, organic compounds at the freeway location exhibited high hopanes plus steranes-to-total carbon ratios (0.16–1.1 ng μg−1), indicative of different engine configurations, fleet or also lubricating oil formulation. At both locations, PM0.25-bound n-alkanes (C19–C34) showed a predominance of high molecular weight homologues and no carbon number preference, suggesting their likely road dust source. Findings of this work indicate that ambient particles at the urban background site in Beirut are mainly of secondary origin and exist in significantly lower levels relative to PM at the roadside location. Particle emissions at the near-freeway site markedly exceed those measured at roadways in similar areas in the U.S. with comparable meteorology and geomorphology. Compared to I-710—a diesel-impacted freeway in Southern California—levels of potentially toxic vehicular tracers are 5 (EC) and 3.7 (PAHs) times greater at the freeway in this study.
•PM levels are dominated by PM10–2.5 and PM0.25 (36–43% of PM10).•PM levels are 1.3–2.6 times greater at the freeway than background location.•PM at the background site is mainly influenced by secondary sources.•PM at the freeway is dominated by vehicular emissions from road dust and tailpipe.•EC and PAHs levels are 5 and 3.7 times greater at the roadside than I-710 in LA.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UL, UM, UPCLJ, UPUK
Exposure to air pollutants has been associated with deleterious health effects that cause premature mortality and a range of morbidities. Air quality in the Mediterranean is of particular interest ...due to an array of environmental and anthropogenic conditions that make it an air-pollution hotspot. However, the scarcity of data for the region's emission inventories inhibits accurate and holistic assessment. Lebanon, located on the eastern board of the Mediterranean, faces several challenges including an unsustainable transport sector, an unregulated power generation sector, and high urban densities, all of which amplify the air-quality crisis. This paper presents an air pollutant emission inventory for two major emission sources in Lebanon, diesel generators and light duty vehicles (LDVs) of the transport sector, and uncovers trends for over a decade. The exhaust emissions for carbon dioxide, nitrogen oxide, carbon monoxide, sulfur dioxide, and fine particulate matter for diesel generators and for LDVs were estimated by assimilating different approaches and data sources through the use of survey data and national statistics for a higher tier. Our results uncovered that diesel generators consumed almost 1.6 million tons of fuel and emitted about 2 Gg of fine particulate matter in 2016. LDVs doubled in number over a decade and were responsible for approximately 0.20 Gg of fine particulate matter emissions in 2015. While the market for diesel generators appeared to have saturated, ownership of passenger cars per passengers continued to increase, while vehicle age, conditions, and, thus, emissions continued to augment. The results highlight the need for greater government intervention to meet the national electricity demand and promote public transportation and discourage private transportation, especially for energy-inefficient vehicles.
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•Fuel consumption for diesel generators increased by 133.5% between 2010 and 2012.•Diesel generators emitted around 2 Gg of fine particulate matter.•The number of light duty vehicles doubled and reached an average age of 19 years in 2015.•The fraction of diesel light duty vehicles increased from 7% to 12% over a decade.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UL, UM, UPCLJ, UPUK
Sesquiterpene lactones (SLs) are one of the most diverse bioactive secondary metabolites found in plants and exhibit a broad range of therapeutic properties . SLs have been showing promising ...potential in cancer clinical trials, and the molecular mechanisms underlying their anticancer potential are being uncovered. Recent evidence also points to a potential utility of SLs in cancer prevention.
This work evaluates SLs with promising anticancer potential based on cell, animal, and clinical models: Artemisinin, micheliolide, thapsigargin dehydrocostuslactone, arglabin, parthenolide, costunolide, deoxyelephantopin, alantolactone, isoalantolactone, atractylenolide 1, and xanthatin as well as their synthetic derivatives. We highlight actionable molecular targets and biological mechanisms underlying the anticancer therapeutic properties of SLs. This is complemented by a unique assessment of SL mechanisms of action that can be exploited in cancer prevention. We also provide insights into structure-activity and pharmacokinetic properties of SLs and their potential use in combination therapies.
We extract seven major lessons learned and present evidence-based solutions that can circumvent some scientific limitations or logistic impediments in SL anticancer research. SLs continue to be at the forefront of cancer drug discovery and are worth a joint interdisciplinary effort in order to leverage their potential in cancer therapy and prevention.
Over the past decade, several citizen science projects have been launched, with a smaller subset addressing citizen scientists' involvement in water quality monitoring. Most of these projects were ...conducted in developed countries and focused on qualitative assessment and measurements of a limited number of water quality parameters. Moreover, data generated by citizen scientists were mainly for monitoring purposes and rarely resulted in remedial measures. In this work, a collaborative citizen science approach involving local citizens and university researchers was applied to assess the groundwater quality in a Lebanese village. Using a mobile laboratory, winter and summer sampling campaigns were conducted and 12 physical, chemical and biological water quality parameters were tested. Results indicated that the data generated by the citizen scientists were comparable with those generated by university researchers for the majority of physical and chemical water quality parameters. However, the bacteriological test results showed a marked difference and may be attributed to the complexity of the testing procedure and quality of testing material. The collaborative and participatory approach resulted in building local capacity and knowledge and in the formation of a locally elected water committee which will be responsible for continuous monitoring of the groundwater resources.
The wide pH range reported for electronic cigarette (ECIG) liquids indicates that nicotine may be present in one or more chemical forms. The nicotine form affects the bioavailability and delivery of ...nicotine from inhaled products. Protonated nicotine is normally associated with counteranions in tobacco products. The chemical and physical properties of counteranions may differently influence the nicotine form and emissions in ECIG aerosols. In this study, we examined how these anions influence nicotine emissions and their evaporation behavior and potential decomposition during ECIG operation. ECIG liquid solutions with equal nicotine concentration and pH but different counteranions (formate, acetate, and citrate) were prepared from analytical standards to assess the effect of the counteranion on nicotine partitioning. High performance liquid and gas chromatography methods were developed to determine the counteranions and the two protonated (NicH+) and free base (Nic) forms of nicotine in commercially available and standard solutions of ECIG liquids and aerosols. In commercial samples, acetate and citrate anions were detected. In standard solutions, both formate and acetate ions were found to evaporate intact, but citrate ion decomposed into formic acid and other products. This study also shows that the identity of the counteranion has no effect on total nicotine emission from ECIG in agreement with previous reports on tobacco cigarettes. However, the partitioning of aerosolized nicotine into NicH+ and Nic is anion-dependent even when the parent liquid pH is held constant. These results indicate that the anions found in a given ECIG product may influence the nicotine delivery profile to the user by enriching aerosols with free-base nicotine as in the case of polycarboxylic acids such as citric acid.
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IJS, KILJ, NUK, PNG, UL, UM
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