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Introduction: Polysubstance use--the use of multiple substances on the same or different occasions--is a risk factor for substance use disorder. However, national surveillance of substance use in Canada has often focused on use of a single substance. To better understand and address polysubstance use, this study characterized the use of vaping products, cigarettes, inhaled cannabis, and alcohol among Canadians aged 15 years and older., Methods: Nationally representative data from the 2020 Canadian Tobacco and Nicotine Survey were analyzed. Polysubstance use was assessed as use of at least two of the following in the past 30 days: smoking cigarettes, using vaping products (containing nicotine or flavours), using cannabis (in smoked and/or vaped form) and drinking alcohol (daily or weekly frequency)., Results: In 2020, past-30-day use of the examined substances was 4.7% for vaping products (1.5 million), 10.3% for cigarettes (3.2 million), 11.0% for inhaled cannabis (3.4 million), and 37.6% for weekly or daily use of alcohol (11.7 million). Polysubstance use was reported by 12.2% of Canadians (3.8 million) and was more prevalent among young Canadians, men and those who vaped. The most common combination of substances among polysubstance users included inhaled cannabis and weekly or daily use of alcohol (29.0%, or 1.1 million)., Conclusion: The use of vaping products, cigarettes, inhaled cannabis, and alcohol-individually and in combination-is substantial among Canadians. Frequent consumption of alcohol was most prevalent overall and, in contrast to the other examined substances, was common among Canadians of all ages. Findings may inform a polysubstance use approach for prevention policies and programs.

Background: Robust surveillance of vaping product use (with or without nicotine) in Canada has been limited by the use of multiple tools with varying designs and content. The objective of the current study was to examine trends over time in vaping prevalence and to examine associated factors using data from the Canadian Community Health Survey (CCHS)., Data and Methods: Trends in the prevalence of past-30-day vaping over time were examined using data available from optional modules of the CCHS for Ontario from 2015 to 2018 and for Quebec from 2017 to 2019. Multiple logistic regression models were used to examine correlates of vaping in Quebec (2019) and Ontario (2018)., Results: Vaping increased in Quebec from 3.4% (233,000) in 2017 to 4.2% (296,000) in 2018 and 4.7% (333,000) in 2019. In Ontario, vaping remained stable in the years 2015 (3.1% or 357,000), 2016 (2.7% or 311,000) and 2017 (2.7% or 309,000), then increased in 2018 (3.4% or 404,000). Increases in vaping in both provinces were driven by youth. Vaping was significantly associated with young age and cigarette smoking in both provinces, as well as with cannabis use in the past 12 months among Quebec respondents., Interpretation: In both provinces, increases in youth vaping were observed in recent years, and this is consistent with national trends. Study findings further our understanding of vaping behaviour and highlight the utility of the CCHS as an additional tool for surveillance of vaping product use among Canadians.

Background: Secondhand smoke exposure (SHSe) is associated with numerous adverse health effects and is a major burden for those who do not smoke. SHSe has been primarily characterized via questionnaire, but exposure levels can also be estimated using a specific biomarker, such as cotinine (COT)., Data and Methods: Urinary COT measurements and questionnaire data from three cycles (2007 to 2013) of the Canadian Health Measures Survey were combined and analyzed as indicators of regular SHSe for nonsmokers aged 6 to 79 years. Exposure extent was examined by demographic and socioeconomic variable, dwelling type, and exposure location., Results: Among Canadian nonsmokers, 22% reported having been regularly exposed to smoke; of those, 26% had detectable COT. The range of SHSe significantly differed by age group and exposure location. While the most frequently reported location category was "outside their home" (16%), the most important contributor to elevated COT was exposure "at home". The creatinine-adjusted COT geometric mean (C_COT-GM) for the nonsmokers aged 6 to 79 reporting regular home exposure was 3.7 μg/g, but the C_COT-GM was almost three times higher for those living in an apartment than for those in a single-detached home. Some discrepancy appeared between self-reported SHSe and detectable COT estimates for the assessed subpopulations., Discussion: Surveillance by questionnaire and biomonitoring both have their own advantages and are fundamental in identifying the subpopulations most susceptible to SHSe. Using a biomarker provides a quantitative estimate of relative exposure that can be compared over time and with other studies, and this is of particular interest for effective public health interventions.

This Article describes a strategy to stabilize a phospholipid monolayer directly on the surface of a H-terminated silicon substrate in order to provide a useful platform for silicon based biosensors. The stabilization of an acrylated phospholipid monolayer is obtained by two-dimensional chain polymerization. As the formation of the lipid monolayer in aqueous solution competes with the oxidation of the silicon surface, several cycles of oxide removal and lipid exposure are necessary to densify the lipid layer. Lipid monolayer formation is followed by Fourier transform infrared spectroscopy. The resulting monolayer is denser than corresponding alkyl monolayers formed on H-terminated silicon via photochemical or thermally initiated reactions.

We present experimental and theoretical results of label-free molecular sensing using the transverse magnetic mode of a 0.22 mum thick silicon slab waveguide with a surface grating implemented in a guided mode resonance configuration. Due to the strong overlap of the evanescent field of the waveguide mode with a molecular layer attached to the surface, these sensors exhibit high sensitivity, while their fabrication and packaging requirements are modest. Experimentally, we demonstrate a resonance wavelength shift of approximately 1 nm when a monolayer of the protein streptavidin is attached to the surface, in good agreement with calculations based on rigorous coupled wave analysis. In our current optical setup this shift corresponds to an estimated limit of detection of 0.2% of a monolayer of streptavidin.

We demonstrate folded waveguide ring resonators for biomolecular sensing. We show that extending the ring cavity length increases the resonator quality factor, and thereby enhances the sensor resolution and minimum level of detection, while at the same time relaxing the tolerance on the coupling conditions to provide stable and large resonance contrast. The folded spiral path geometry allows a 1.2 mm long ring waveguide to be enclosed in a 150 microm diameter sensor area. The spiral cavity resonator is used to monitor the streptavidin protein binding with a detection limit of approximately 3 pg/mm(2), or a total mass of approximately 5 fg. The real time measurements are used to analyze the kinetics of biotin-streptavidin binding.

We demonstrate a new silicon photonic wire waveguide evanescent field (PWEF) sensor that exploits the strong evanescent field of the transverse magnetic mode of this high-index-contrast, submicrometer-dimension waveguide. High sensitivity is achieved by using a 2 mm long double-spiral waveguide structure that fits within a compact circular area of 150 microm diameter, facilitating compatibility with commercial spotting apparatus and the fabrication of densely spaced sensor arrays. By incorporating the PWEF sensor element into a balanced waveguide Mach-Zehnder interferometer circuit, a minimum detectable mass of approximately 10 fg of streptavidin protein is demonstrated with near temperature-independent response.

A series of Dmt-Tic analogues with substitution on the Tic aromatic ring has been synthesized and evaluated for opioid receptor affinity and activation. Incorporation of large hydrophobic groups at position 7 of Tic did not greatly alter the delta opioid receptor binding affinities of the dipeptides whereas substitution at position 6 substantially diminished their affinity. These modified Dmt-Tic peptides showed binding affinities as low as 2.5 nM with up to 500-fold selectivity for the delta versus mu opioid receptor and proved to be delta receptor antagonists.