The generative potential of mess in community-based participatory research with young people who use(d) drugs in Vancouver.

Community-based participatory research (CBPR) is increasingly standard practice for critical qualitative health research with young people who use(d) drugs in Vancouver, Canada. One aim of CBPR in this context is to redress the essentialization, erasure, and exploitation of people who use(d) drugs in health research. In this paper, we reflect on a partnership that began in 2018 between three university researchers and roughly ten young people (ages 17-28) who have current or past experience with drug use and homelessness in Greater Vancouver. We focus on moments when our guiding principles of shared leadership, safety, and inclusion became fraught in practice, forcing us in some cases to re-imagine these principles, and in others to accept that certain ethical dilemmas in research can never be fully resolved. We argue that this messiness can be traced to the complex and diverse positionalities of each person on our team, including young people. As such, creating space for mess was ethically necessary and empirically valuable for our CBPR project.

Quantifying the impact of immune history and variant on SARS-CoV-2 viral kinetics and infection rebound: A retrospective cohort study.

Background: The combined impact of immunity and SARS-CoV-2 variants on viral kinetics during infections has been unclear. Methods: We characterized 1,280 infections from the National Basketball Association occupational health cohort identified between June 2020 and January 2022 using serial RT-qPCR testing. Logistic regression and semi-mechanistic viral RNA kinetics models were used to quantify the effect of age, variant, symptom status, infection history, vaccination status and antibody titer to the founder SARS-CoV-2 strain on the duration of potential infectiousness and overall viral kinetics. The frequency of viral rebounds was quantified under multiple cycle threshold (Ct) value-based definitions. Results: Among individuals detected partway through their infection, 51.0% (95% credible interval [CrI]: 48.3-53.6%) remained potentially infectious (Ct <30) 5 days post detection, with small differences across variants and vaccination status. Only seven viral rebounds (0.7%; N=999) were observed, with rebound defined as 3+days with Ct <30 following an initial clearance of 3+days with Ct ≥30. High antibody titers against the founder SARS-CoV-2 strain predicted lower peak viral loads and shorter durations of infection. Among Omicron BA.1 infections, boosted individuals had lower pre-booster antibody titers and longer clearance times than non-boosted individuals. Conclusions: SARS-CoV-2 viral kinetics are partly determined by immunity and variant but dominated by individual-level variation. Since booster vaccination protects against infection, longer clearance times for BA.1-infected, boosted individuals may reflect a less effective immune response, more common in older individuals, that increases infection risk and reduces viral RNA clearance rate. The shifting landscape of viral kinetics underscores the need for continued monitoring to optimize isolation policies and to contextualize the health impacts of therapeutics and vaccines. Funding: Supported in part by CDC contract #200-2016-91779, a sponsored research agreement to Yale University from the National Basketball Association contract #21-003529, and the National Basketball Players Association.

A systematic approach to understand hydrogeochemical dynamics in large river systems: Development and application to the River Ganges (Ganga) in India.

Large river systems, such as the River Ganges (Ganga), provide crucial water resources for the environment and society, yet often face significant challenges associated with cumulative impacts arising from upstream environmental and anthropogenic influences. Understanding the complex dynamics of such systems remains a major challenge, especially given accelerating environmental stressors including climate change and urbanization, and due to limitations in data and process understanding across scales. An integrated approach is required which robustly enables the hydrogeochemical dynamics and underpinning processes impacting water quality in large river systems to be explored. Here we develop a systematic approach for improving the understanding of hydrogeochemical dynamics and processes in large river systems, and apply this to a longitudinal survey (> 2500 km) of the River Ganges (Ganga) and key tributaries in the Indo-Gangetic basin. This framework enables us to succinctly interpret downstream water quality trends in response to the underpinning processes controlling major element hydrogeochemistry across the basin, based on conceptual water source signatures and dynamics. Informed by a 2019 post-monsoonal survey of 81 river bank-side sampling locations, the spatial distribution of a suite of selected physico-chemical and inorganic parameters, combined with segmented linear regression, reveals minor and major downstream hydrogeochemical transitions. We use this information to identify five major hydrogeochemical zones, characterized, in part, by the inputs of key tributaries, urban and agricultural areas, and estuarine inputs near the Bay of Bengal. Dominant trends are further explored by investigating geochemical relationships (e.g. Na:Cl, Ca:Na, Mg:Na, Sr:Ca and NO3:Cl), and how water source signatures and dynamics are modified by key processes, to assess the relative importance of controls such as dilution, evaporation, water-rock interactions (including carbonate and silicate weathering) and anthropogenic inputs. Mixing/dilution between sources and water-rock interactions explain most regional trends in major ion chemistry, although localized controls plausibly linked to anthropogenic activities are also evident in some locations. Temporal and spatial representativeness of river bank-side sampling are considered by supplementary sampling across the river at selected locations and via comparison to historical records. Limitations of such large-scale longitudinal sampling programs are discussed, as well as approaches to address some of these inherent challenges. This approach brings new, systematic insight into the basin-wide controls on the dominant geochemistry of the River Ganga, and provides a framework for characterising dominant hydrogeochemical zones, processes and controls, with utility to be transferable to other large river systems.

Thermal decomposition of hybrid ultramicroporous materials (HUMs).

Hybrid Ultramicroporous Materials (HUMs) are porous coordination materials with exemplary gas sorption and separation characteristics, but relatively poor thermal stability when compared to other porous coordination polymers or metal-organic frameworks (MOFs). The origin of this poor thermal stability has not yet been experimentally verified. Therefore, we investigate the thermal decomposition mechanisms of representative HUMs with the general formulae [M(SiF6)(L)2] or [M(SiF6)(L)(H2O)2], where M = Ni(ii), Cu(ii) or Zn(ii) and L = pyrazine or 4,4'-bipyridine. We find that two decomposition mechanisms dominate: (i) the fragmentation of the XF62- pillar into gaseous XF4 and fluoride, and (ii) direct sublimation of the N-donor ligand. The former process dictates the overall thermal stability of the material. We also demonstrate that HF is a possible decomposition product from certain hydrated HUM materials.

"Something that actually works": Cannabis use among young people in the context of street entrenchment.

BACKGROUND: Cannabis is one of the most widely used substances among vulnerable young people (<26 years of age) experiencing street entrenchment. Although previous research has documented the role cannabis can play in harm reduction, substance use and mental health treatment and pain management, this research has predominantly been quantitative and focused on adult drug-using populations. Little qualitative work has examined how young people who use drugs understand, experience, and engage with cannabis in the context of street entrenchment and drug use trajectories that include the use of other substances such as alcohol, opioids and crystal methamphetamine (meth). METHODS: Semi-structured, in-depth qualitative interviews were conducted between 2017 and 2019 with 56 young people recruited from a cohort of street-involved youth in Vancouver, Canada. We also conducted 13 interviews with 12 youth-focused care providers across the same time period. Interview data were triangulated by drawing on the findings of a program of anthropological research conducted by the senior author since 2008. Interviews were transcribed verbatim and thematic analysis was conducted. RESULTS: The vast majority of study participants engaged in daily, intensive cannabis use at the same time as they cycled on and off other substances that were perceived as much more harmful (primarily alcohol, fentanyl, heroin and meth). While most participants derived significant pleasure from the use of cannabis, no participants in our study described using cannabis for purely recreational purposes. A number of participants explicitly framed cannabis as a form of mental health and substance use treatment that was more effective and "healthier" than the long-term use of psychopharmaceuticals and medication-assisted substance use treatment (e.g., opioid agonist therapies). Cannabis use was also understood to ameliorate some of the harms of, or even facilitate transitions out of, periods of street-based homelessness. While the majority of our participants highlighted the positive effects of regular cannabis consumption, some described how intensive cannabis use could generate significant harms. CONCLUSION: In the context of the recent legalization of non-medical cannabis use in Canada and amid ongoing overdose and housing crises, it is imperative that future policy and programming interventions and provider education and training be responsive to the ways in which vulnerable youth in our setting are actively using cannabis to navigate their everyday lives and healthcare needs.