Differences in use of electronic nicotine delivery systems by smoking status and demographic characteristics among Australian young adults

Issue addressed: Electronic nicotine delivery systems (ENDS) continue to grow in popularity, particularly among young adults. Understanding by whom various ENDS are being used and why within this population segment can assist the development of appropriate interventions targeting those most vulnerable to use and inform policy decisions in this area. Accordingly, this study assessed the demographic characteristics associated with ENDS use among Australian young adults, and reasons for current e-cigarette use. Methods: An online survey was administered to 1116 Australians aged 18-25 years (59% female). Results: Smokers were more likely than non-smokers to report (a) ever use of ENDS (67% vs 28%), (b) ever use of an e-cigarette (64% vs 24%), e-cigar (17% vs 8%) or e-hookah (15% vs 8%) and (c) current use of e-cigarettes (19% vs 6%). Male smokers were more likely than female smokers to be current e-cigarette users. The most common reason for current e-cigarette use was enjoyment. Conclusions: Young male adults appear to be particularly vulnerable to becoming regular e-cigarette users. This demographic group may need to be a primary focus of prevention and intervention efforts. Contrary to popular belief, smoking cessation was not a primary reason for e-cigarette use. So what?: Greater efforts are needed to educate young adults on the harms associated with ENDS use, especially if use is being driven by the perception that they are a harmless means of amusement. Maintaining existing regulations limiting the accessibility of these products is crucial to ensuring widespread use is minimised

Biomarkers of exposure to new and emerging tobacco delivery products

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 tobaccoderived 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

H-infinity filter design for nonlinear systems with quantised measurements in finite frequency domain

International audienceThis paper deals with the problem of finite frequency (FF) H-infinity full-order fuzzy filter design for nonlinear discrete-time systems with quantised measurements, described by Takagi-Sugeno models. The measured signals are assumed to be quantised with a logarithmic quantiser. Using a fuzzy-basis-dependent Lyapunov function, the finite frequency l(2) gain definition, the generalised S-procedure, and Finsler's lemma, a set of sufficient conditions are established in terms of matrix inequalities, ensuring that the filtering error system is stable and the H-infinity attenuation level, from disturbance to the estimation error, is smaller than a given value over a prescribed finite frequency domain of the external disturbances. With the aid of Finsler's lemma, a large number of slack variables are introduced to the design conditions, which provides extra degrees of freedom in optimising the guaranteed H-infinity performance. This directly leads to performance improvement and reduction of conservatism. Finally, we give a simulation example to demonstrate the efficiency of the proposed design method, and we show that a lower H-infinity attenuation level can be obtained by our developed approach in comparison with another result in the literature

Calculation of Ionization Energy, Electron Affinity, and Hydride Affinity Trends in Pincer-Ligated d⁸‑Ir(^tBu4PXCXP) Complexes: Implications for the Thermodynamics of Oxidative H₂ Addition

DFT methods are used to calculate the ionization energy (IE) and electron affinity (EA) trends in a series of pincer ligated d⁸-Ir­(^tBu4PXCXP) complexes (<b>1</b>-X), where C is a 2,6-disubstituted phenyl ring with X = O, NH, CH₂, BH, S, PH, SiH₂, and GeH₂. Both <i>C</i>_2<i>v</i> and <i>C</i>₂ geometries are considered. Two distinct σ-type (²A₁ or ²A) and π-type (²B₁ or ²B) electronic states are calculated for each of the free radical cation and anion. The results exhibit complex trends, but can be satisfactorily accounted for by invoking a combination of electronegativity and specific π-orbital effects. The calculations are also used to study the effects of varying X on the thermodynamics of oxidative H₂ addition to <b>1</b>-X. Two closed shell singlet states differentiated in the <i>C</i>₂ point group by the d⁶-electon configuration are investigated for the five-coordinate Ir­(III) dihydride product. One electronic state has a d⁶-(a)²(b)²(b)² configuration and a square pyramidal geometry, the other a d⁶-(a)²(b)²(a)² configuration with a distorted-Y trigonal bipyramidal geometry. No simple correlations are found between the computed reaction energies of H₂ addition and either the IEs or EAs. To better understand the origin of the computed trends, the thermodynamics of H₂ addition are analyzed using a cycle of hydride and proton addition steps. The analysis highlights the importance of the electron and hydride affinities, which are not commonly used in rationalizing trends of oxidative addition reactions. Thus, different complexes such as <b>1</b>-O and <b>1</b>-CH₂ can have very similar reaction energies for H₂ addition arising from opposing hydride and proton affinity effects. Additional calculations on methane C–H bond addition to <b>1</b>-X afford reaction and activation energy trends that correlate with the reaction energies of H₂ addition leading to the Y-product

Free-Base and Protonated Nicotine in Electronic Cigarette Liquids and Aerosols

As with other tobacco aerosols, nicotine delivery from e-cigarettes (ECIG) depends on the total nicotine and its partitioning between free-base (Nic) and protonated (NicH⁺) forms. Previous studies of ECIG nicotine emissions have generally reported “nicotine yield” without attention to whether the methods employed resulted in quantification of the total nicotine or only one of its forms, making reported results difficult to compare across studies or to evaluate against reported blood exposure. This study reports a convenient solvent extraction method for determining total nicotine and its partitioning in ECIG liquids and aerosols by gas chromatography. Commercial ECIG liquids and aerosols were analyzed, and it was found that most of the nicotine was in the Nic form, with aerosols exhibiting higher Nic fraction than the parent liquids. Apparent pH was found to correlate with nicotine partitioning and can provide a useful indirect measure when chromatography is unavailable. Finally, labeled ECIG liquid nicotine concentration in commercial products was often inconsistent with measured nicotine