Search

Rationale: Evidence linking outdoor air pollution with coronavirus disease (COVID-19) incidence and mortality is largely based on ecological comparisons between regions that may differ in factors such as access to testing and control measures that may not be independent of air pollution concentrations. Moreover, studies have yet to focus on key mechanisms of air pollution toxicity such as oxidative stress. Objectives: To conduct a within-city analysis of spatial variations in COVID-19 incidence and the estimated generation of reactive oxygen species (ROS) in lung lining fluid attributable to fine particulate matter (particulate matter with an aerodynamic diameter ⩽2.5 μm [PM2.5]). Methods: Sporadic and outbreak-related COVID-19 case counts, testing data, population data, and sociodemographic data for 140 neighborhoods were obtained from the City of Toronto. ROS estimates were based on a mathematical model of ROS generation in lung lining fluid in response to iron and copper in PM2.5. Spatial variations in long-term average ROS were predicted using a land-use regression model derived from measurements of iron and copper in PM2.5. Data were analyzed using negative binomial regression models adjusting for covariates identified using a directed acyclic graph and accounting for spatial autocorrelation. Measurements and Main Results: A significant positive association was observed between neighborhood-level ROS and COVID-19 incidence (incidence rate ratio = 1.07; 95% confidence interval, 1.01-1.15 per interquartile range ROS). Effect modification by neighborhood-level measures of racialized group membership and socioeconomic status was also identified. Conclusions: Examination of neighborhood characteristics associated with COVID-19 incidence can identify inequalities and generate hypotheses for future studies.

Motivated by the need to predict how the Arctic atmosphere will change in a warming world, this article summarizes recent advances made by the research consortium NETCARE (Network on Climate and Aerosols: Addressing Key Uncertainties in Remote Canadian Environments) that contribute to our fundamental understanding of Arctic aerosol particles as they relate to climate forcing. The overall goal of NETCARE research has been to use an interdisciplinary approach encompassing extensive field observations and a range of chemical transport, earth system, and biogeochemical models. Several major findings and advances have emerged from NETCARE since its formation in 2013. (1) Unexpectedly high summertime dimethyl sulfide (DMS) levels were identified in ocean water (up to 75 nM) and the overlying atmosphere (up to 1 ppbv) in the Canadian Arctic Archipelago (CAA). Furthermore, melt ponds, which are widely prevalent, were identified as an important DMS source (with DMS concentrations of up to 6 nM and a potential contribution to atmospheric DMS of 20 % in the study area). (2) Evidence of widespread particle nucleation and growth in the marine boundary layer was found in the CAA in the summertime, with these events observed on 41 % of days in a 2016 cruise. As well, at Alert, Nunavut, particles that are newly formed and grown under conditions of minimal anthropogenic influence during the months of July and August are estimated to contribute 20 % to 80 % of the 30-50 nm particle number density. DMS-oxidation-driven nucleation is facilitated by the presence of atmospheric ammonia arising from seabird-colony emissions, and potentially also from coastal regions, tundra, and biomass burning. Via accumulation of secondary organic aerosol (SOA), a significant fraction of the new particles grow to sizes that are active in cloud droplet formation. Although the gaseous precursors to Arctic marine SOA remain poorly defined, the measured levels of common continental SOA precursors (isoprene and monoterpenes) were low, whereas elevated mixing ratios of oxygenated volatile organic compounds (OVOCs) were inferred to arise via processes involving the sea surface microlayer. (3) The variability in the vertical distribution of black carbon (BC) under both springtime Arctic haze and more pristine summertime aerosol conditions was observed. Measured particle size distributions and mixing states were used to constrain, for the first time, calculations of aerosol-climate interactions under Arctic conditions. Aircraft- and ground-based measurements were used to better establish the BC source regions that supply the Arctic via long-range transport mechanisms, with evidence for a dominant springtime contribution from eastern and southern Asia to the middle troposphere, and a major contribution from northern Asia to the surface. (4) Measurements of ice nucleating particles (INPs) in the Arctic indicate that a major source of these particles is mineral dust, likely derived from local sources in the summer and long-range transport in the spring. In addition, INPs are abundant in the sea surface microlayer in the Arctic, and possibly play a role in ice nucleation in the atmosphere when mineral dust concentrations are low. (5) Amongst multiple aerosol components, BC was observed to have the smallest effective deposition velocities to high Arctic snow (0.03 cm s1).

Information overload and limited laboratory time usually result in students focusing mostly on procedural tasks to get the results, rather than being engaged with what they are doing. Moreover, traditional laboratory curricula rarely provide students opportunities to repeat experiments. This study presents the design of a web-based application framework for the development of interactive postlaboratory exercises that complement and extend the hands-on laboratories. The framework has four main modules: (1) a video module to present information and concepts through embedded videos, (2) a virtual lab module to perform experiments, (3) a reaction mechanism module to practice drawing reaction mechanisms, and (4) a formative assessment module including questions and explanatory feedback to guide students and to encourage reflection. On the basis of this framework, postlaboratory exercises have been developed for two experiments in an undergraduate chemistry laboratory course. The exercises allowed students to reinforce and extend the laboratory-gained knowledge in a new virtual context by comparing two different chemical reactions related to the experiments they had performed. A survey conducted at the end of the exercises revealed that a majority of students found the postlaboratory exercises helpful and thought they provided an opportunity for application and helped with reinforcing theory and integrating concepts.

Engineering is developing extensive leadership education, supporting future professional engineers to engage with others in solving complex sociotechnical problems. A contemporary challenge is to integrate leadership learning into foundational coursework requirements.

Abstract. Motivated by the need to predict how the Arctic atmosphere will change in a warming world, this article summarizes recent advances made by the research consortium NETCARE (Network on Climate and Aerosols: Addressing Key Uncertainties in Remote Canadian Environments) that contribute to our fundamental understanding of Arctic aerosol particles as they relate to climate forcing. The overall goal of NETCARE research has been to use an interdisciplinary approach encompassing extensive field observations and a range of chemical transport, earth system, and biogeochemical models. Several major findings and advances have emerged from NETCARE since its formation in 2013 . (1) Unexpectedly high summertime dimethyl sulfide (DMS) levels were identified in ocean water and the overlying atmosphere in the Canadian Arctic Archipelago (CAA). Furthermore, melt ponds, which are widely prevalent, were identified as an important DMS source. (2) Evidence was found of widespread particle nucleation and growth in the marine boundary layer in the CAA in the summertime. DMS-oxidation-driven nucleation is facilitated by the presence of atmospheric ammonia arising from sea bird colony emissions, and potentially also from coastal regions, tundra, and biomass burning. Via accumulation of secondary organic material (SOA), a significant fraction of the new particles grow to sizes that are active in cloud droplet formation. Although the gaseous precursors to Arctic marine SOA remain poorly defined, the measured levels of common continental SOA precursors (isoprene and monoterpenes) were low, whereas elevated mixing ratios of oxygenated volatile organic compounds were inferred to arise via processes involving the sea surface microlayer. (3) The variability in the vertical distribution of black carbon (BC) under both springtime Arctic haze and more pristine summertime aerosol conditions was observed. Measured particle size distributions and mixing states were used to constrain, for the first time, calculations of aerosol–climate interactions under Arctic conditions. Aircraft- and ground-based measurements were used to better establish the BC source regions that supply the Arctic via long-range transport mechanisms. (4) Measurements of ice nucleating particles (INPs) in the Arctic indicate that a major source of these particles is mineral dust, likely derived from local sources in the summer and long-range transport in the spring. In addition, INPs are abundant in the sea surface microlayer in the Arctic, and possibly play a role in ice nucleation in the atmosphere when mineral dust concentrations are low. (5) Amongst multiple aerosol components, BC was observed to have the smallest effective deposition velocities to high Arctic snow.

BackgroundThe mission of the International Confederation of Plastic Surgery Societies (ICOPLAST) is to improve patient outcomes through collaboratively structured processes in education, advocacy and communication. This article explains how we approached the task of establishing priorities for this nascent confederation in an equitable and achievable manner.MethodsIn late 2016, an online survey was sent to the inaugural 62 ICOPLAST member national societies for dissemination to their respective plastic surgeon members. Functional domains and proposed initiatives were ranked according to their level of importance by individual plastic surgeons.ResultsThe survey was completed by 572 plastic surgeons. As a functional domain, education was highly ranked by 75.3% of respondents, followed by patient safety (67.4%), communication (59.3%), humanitarian (46.6%), regulation (41.2%), and advocacy (41.1%). Respondents also ranked individual initiatives within each domain to produce a compilation list of the top 13 initiatives of importance.ConclusionThis study has identified priorities of importance to ICOPLAST members, which will aid in building a strategic framework and enhancing outcomes for patients, plastic surgeons, and the field of plastic surgery more broadly.

In recent years engineering educators have been encouraged to blend technical and professional learning in their curricular and co-curricular programming (Engineers Canada, 2009; National Academy of Engineering [NAE], 2004). Our paper describes a multifaceted leadership learning program developed to achieve this goal by infusing reflective, experiential learning into an otherwise technically oriented discipline. The program was designed by a collaborative team of educators and researchers with backgrounds in engineering, education, psychology, and industry and offers a range of learning experiences using diverse pedagogical strategies. The content covers four realms of leadership corresponding to four levels of analysis: self, team, organization, and society. Learning experiences include elective academic courses, co-curricular workshop programs, guest lectures in core courses, seminars, department based leadership groups, and panel discussions. In this paper, we describe the program goals, curricular and co-curricular initiatives and early research findings in order to scaffold an emerging discussion about engineering leadership education in Canada. Informal feedback from students who have participated in our program provide us with preliminary evidence that students are learning, that they value the learning opportunities afforded by our program,and that our initiative is enabling significant personal growth.

Laboratory-based learning can be weakened by a lack of connection with underlying theory and limited contextualization to enhance motivation. To address these shortcomings, a framework for the development of web-based multimedia prelaboratory modules is proposed. The framework incorporates supportive information (content), utility value (context), multimedia design principles (design), and questions/explanatory feedback (formative assessment). On the basis of this framework, prelaboratory modules were developed for three second-year organic chemistry experiments in a chemical engineering course. Each module consists of a few short animation videos and a few questions. The videos include explanation of theories and justification for experimental procedures (supportive information), as well as explanation of utility value to increase student motivation. The effectiveness of the modules was assessed through multiple strategies including a survey with learning and utility value/motivation constructs, student grades for the modules, time spent on the modules, and the number of times videos were watched. Students in general expressed positive views regarding the prelaboratory modules in terms of understanding and relating theory to procedures, and understanding the utility value of the material. Half of the students reported increased motivation as a result of understanding the utility value of the knowledge they acquired. Thus, prelaboratory exercises based on this framework may alleviate some of the educational challenges in undergraduate laboratories.

This paper presents the findings from a collaborative interlaboratory comparison exercise designed to assess oxidative potential (OP) measurements conducted by 20 laboratories worldwide. This study represents an innovative effort as the first exercise specifically aimed at harmonising this type of OP assay, setting a new benchmark in the field. Over the last decade, there has been a noticeable increase in OP studies, with numerous research groups investigating the effects of exposure to air pollution particles through the evaluation of OP levels. However, the absence of standardised methods for OP measurements has resulted in variability in results across different groups, rendering meaningful comparisons challenging. To address this issue, this study engages in an international effort to compare OP measurements using a simplified method (with a dithiothreitol (DTT) assay). Here, we quantify the OP in liquid samples to focus on the protocol measurement itself, while future ILCs should aim to assess the full-chain process, including the sample extraction. We analyse the similarities and discrepancies observed in the results, identifying the critical parameters (such as the instrument used, the use of a simplified protocol, the delivery and analysis time) that could influence OP measurements, and provide recommendations for future studies and interlaboratory comparisons. Even if other crucial aspects, such as sampling PM methods, sample storage, extraction methods and conditions, and the evaluation of other OP assays, still need to be standardised. This collaborative approach enhances the robustness of the OP-DTT assay and paves the way for future studies to build on a unified framework. This pioneering work concludes that interlaboratory comparisons provide essential insights into the OP metric and are crucial to move toward the harmonisation of OP measurements. [ABSTRACT FROM AUTHOR]

ObjectiveParticipants in the Atherosclerosis Prevention in Paediatric Lupus Erythematosus (APPLE) trial were randomised to placebo or atorvastatin for 36 months. The primary endpoint, reduced carotid intima medial thickness (CIMT) progression, was not met but atorvastatin-treated participants showed a trend of slower CIMT progression. Post-hoc analyses were performed to assess subgroup benefit from atorvastatin therapy.MethodsSubgroups were prespecified and defined by age (> or ≤15.5 years), systemic lupus erythematosus (SLE) duration (> or ≤24 months), pubertal status (Tanner score≥4 as post-pubertal or

Background: We do not currently understand how spatiotemporal variations in the composition of fine particulate air pollution [fine particulate matter with aerodynamic diameter [less than or equal to] 2.5 [micro]m ([PM.sub.2.5])] affects population health risks. However, recent evidence suggests that joint concentrations of transition metals and sulfate may influence the oxidative potential (OP) of [PM.sub.2.5] and associated health impacts. Objectives: The purpose of the study was to evaluate how combinations of transition metals/OP and sulfur content in outdoor [PM.sub.2.5] influence associations with acute cardiovascular events. Methods: We conducted a national case-crossover study of outdoor [PM.sub.2.5] and acute cardiovascular events in Canada between 2016 and 2017 (93,344 adult cases). Monthly mean transition metal and sulfur (S) concentrations in [PM.sub.2.5] were determined prospectively along with estimates of OP using acellular assays for glutathione ([OP.sup.GSH]), ascorbate ([OP.sup.AA]), and dithiothreitol depletion ([OP.sup.DTT]). Conditional logistic regression models were used to estimate odds ratios (OR) [95% confidence intervals (CI)] for [PM.sub.2.5] across strata of transition metals/OP and sulfur. Results: Among men, the magnitudes of observed associations were strongest when both transition metal and sulfur content were elevated. For example, an OR of 1.078 (95% CI: 1.049, 1.108) (per 10 [micro]g/[m.sup.3]) was observed for cardiovascular events in men when both copper and S were above the median, whereas a weaker association was observed when both elements were below median values (OR= 1.019, 95% CI: 1.007, 1.031). A similar pattern was observed for OP metrics. [PM.sub.2.5] was not associated with acute cardiovascular events in women. Discussion: The combined transition metal and sulfur content of outdoor [PM.sub.2.5] influences the strength of association with acute cardiovascular events in men. Regions with elevated concentrations of both sulfur and transition metals in [PM.sub.2.5] should be examined as priority areas for regulatory interventions. https://doi.org/10.1289/EHP9449, Introduction Numerous epidemiological studies have documented the acute cardio-respiratory health impacts of outdoor fine particulate air pollution [fine particulate matter with aerodynamic diameter [less than or equal to] 2.5 [micro]m [...]

Background: Oxidative stress plays an important role in the health impacts of both outdoor fine particulate air pollution (PM2.5) and thermal stress. However, it is not clear how the oxidative potential of PM2.5 may influence the acute cardiovascular effects of temperature. Methods: We conducted a case-crossover study of hospitalization for cardiovascular events in 35 cities across Canada during the summer months (July-September) between 2016 and 2018. We collected three different metrics of PM2.5 oxidative potential each month in each location. We estimated associations between lag-0 daily temperature (per 5°C) and hospitalization for all cardiovascular (n = 44,876) and ischemic heart disease (n = 14,034) events across strata of monthly PM2.5 oxidative potential using conditional logistical models adjusting for potential time-varying confounders. Results: Overall, associations between lag-0 temperature and acute cardiovascular events tended to be stronger when outdoor PM2.5 oxidative potential was higher. For example, when glutathione-related oxidative potential (OPGSH) was in the highest tertile, the odds ratio (OR) for all cardiovascular events was 1.040 (95% confidence intervals [CI] = 1.004, 1.074) compared with 0.980 (95% CI = 0.943, 1.018) when OPGSH was in the lowest tertile. We observed a greater difference for ischemic heart disease events, particularly for older subjects (age >70 years). Conclusions: The acute cardiovascular health impacts of summer temperature variations may be greater when outdoor PM2.5 oxidative potential is elevated. This may be particularly important for ischemic heart disease events. [ABSTRACT FROM AUTHOR]