Showing papers by "University of Toronto published in 2023"
TL;DR: In this paper , the authors argue that racism against Eastern Europeans reflects the long-standing imperial rivalry between the West and Russia, which aims to affirm the threatened whiteness of people in the region by distancing them from the Global South.
Abstract: Racial capitalism requires that the subaltern periphery, providing cheap labour and new markets, be placed behind an imagined racial barrier, so that the full protection of the liberal state is not extended to it. This has applied also to the ‘Eastern enlargement’ of the EU. The East has had to compete with a much richer and more powerful West. When, inevitably, the East was unable to ‘catch up’, its ‘failure’ was attributed to its alleged historical and cultural incompatibility with the West. Such racist discourse has penetrated global and European politics, economics, and media. It also affects people who move from the East to the West. Unfortunately, many Eastern Europeans project their own racialisation onto others. This dynamic is articulated from the equivocal position of Eastern Europe, between the core West and the Global South. It aims to affirm the threatened whiteness of people in the region by distancing them from the Global South. But also, it functions within Eastern Europe, with each country to the East imagined as more ‘Eastern European’ until one reaches the prototypical Eastern European nation, Russia. For racism against Eastern Europeans reflects, in the final analysis, the long-standing imperial rivalry between the West and Russia.
10 citations
TL;DR: In this paper , a longitudinal liver sampling using fine-needle aspiration was performed to investigate mechanisms of chronic hepatitis B (CHB) pathogenesis in the human liver, which revealed a distinct liver resident, polyclonal CD8+ T cell population that was enriched at baseline and displayed a highly activated immune signature during liver damage.
Abstract: Accumulation of activated immune cells results in nonspecific hepatocyte killing in chronic hepatitis B (CHB), leading to fibrosis and cirrhosis. This study aims to understand the underlying mechanisms in humans and to define whether these are driven by widespread activation or a subpopulation of immune cells. We enrolled CHB patients with active liver damage to receive antiviral therapy and performed longitudinal liver sampling using fine-needle aspiration to investigate mechanisms of CHB pathogenesis in the human liver. Single-cell sequencing of total liver cells revealed a distinct liver-resident, polyclonal CD8+ T cell population that was enriched at baseline and displayed a highly activated immune signature during liver damage. Cytokine combinations, identified by in silico prediction of ligand-receptor interaction, induced the activated phenotype in healthy liver CD8+ T cells, resulting in nonspecific Fas ligand–mediated killing of target cells. These results define a CD8+ T cell population in the human liver that can drive pathogenesis and a key pathway involved in their function in CHB patients.
7 citations
TL;DR: In this paper , a green and facile synthesis of dielectric-magnetic MXene-Fe nanocomposites via one-step Lewis acidic molten salts etching, which were combined with carbon nanotube (CNT) filler and silicone rubber (SR) matrix to fabricate double-layered transition metal carbide/nitride (MXene) composites by casting and curing.
5 citations
TL;DR: Corporate purpose is taking off as a concept within both the corporate world and management academia as mentioned in this paper . But despite many bold pronouncements by companies about pursuing purpose and not just profits, evidence suggests that these are often decoupled from real action on social and environmental issues.
Abstract: Corporate purpose is taking off as a concept within both the corporate world and management academia. Despite many bold pronouncements by companies about pursuing purpose and not just profits, evidence suggests that these are often decoupled from real action on social and environmental issues. In this essay, I grapple with a number of questions that arise for scholars and practitioners given the state of the field. Is the lack of progress intentional such that corporate purpose is just a power grab for firms to protect their influence and profits? Is making the business case for corporate purpose just part of this power grab? Stepping back, what is corporate purpose anyway? Additionally, how does it relate to trade-offs across stakeholders? Who counts as a stakeholder? How can we account for value distribution along with value creation? How can we conceptualize the firm if we take purpose seriously? What would it mean to decenter the firm (and center the stakeholders) in the practice of corporate purpose? What governance structures are needed to enact corporate purpose? Additionally, what are the implications for a new model of decentered leadership? There are not a lot of answers yet, but this review of recent research in the domain spots many excellent clues and paths for future progress. History: This paper has been accepted by Matt Kraatz for the Strategy Science Special Issue on Corporate Purpose. Funding: The Michael Lee-Chin Institute for Corporate Citizenship at the Rotman School of Management, University of Toronto provided financial support for the author’s research in this domain.
5 citations
TL;DR: In this paper , a review summarizes recent research on brain network studies of anesthesia, and compares the underlying neural mechanisms of consciousness and anesthesia along with the neural signs and measures of the distinct aspects of neural activity.
4 citations
01 Jan 2023
TL;DR: In this article , a CO 2 diffusion layer enabled the production of CO-rich syngas in a direct carbonate electrolysis system, and the diffusion layer was used to improve the performance of the CO 2 mixture.
Abstract: In a direct carbonate electrolysis system, a CO 2 diffusion layer enabled the production of CO-rich syngas.
4 citations
TL;DR: In this paper , the accumulation of Advanced Glycation End-products (AGEs) in collagen decreases its proteolytic degradation rates while increasing its stiffness and the elastic modulus of collagen scaffolds increases.
4 citations
TL;DR: In this article , a novel Janus composite membrane based on the assembly of hydrophilic vermiculite (VMT), multi-walled carbon nanotubes (MWCNTs), and hydrophobic polydimethylsiloxane (PDMS) is designed to function cooperatively for efficient solar absorption and long-term salt-rejection.
3 citations
TL;DR: In this paper , the authors demonstrate how a small gas bubble injected into the vitreous cavity in pneumatic retinopexy for rhegmatogenous retinal detachment causes immediate displacement of subretinal fluid and to gain insights into the potential mechanism of retinal displacement.
Abstract: In Brief Purpose: To demonstrate how a small gas bubble injected into the vitreous cavity in pneumatic retinopexy for rhegmatogenous retinal detachment causes immediate displacement of subretinal fluid and to gain insights into the potential mechanism of retinal displacement. Methods: Three patients with rhegmatogenous retinal detachment who underwent pneumatic retinopexy were enrolled and prospectively followed. All patients underwent ultra-widefield fundus photography at baseline and at 1 to 2 minutes after intravitreal gas injection. Results: In all cases, the ultra-widefield fundus photograph demonstrated immediate displacement of subretinal fluid, suggesting that the buoyant force applied to the retina by the bubble was responsible for the displacement of subretinal fluid. The results were extrapolated to determine the buoyant force applied by a small and large gas bubble as in pneumatic retinopexy and pars plana vitrectomy. We determined that the buoyant force applied with a larger bubble in pars plana vitrectomy was substantially greater, and this may lead to retinal displacement. Conclusion: Intravitreal gas applies significant buoyant force to the detached retina and subretinal fluid that leads to substantial and rapid displacement of subretinal fluid. Understanding the affect of the buoyant force of the gas bubble on the detached retina can provide insight into possible mechanisms of retinal displacement. This case series demonstrates how subretinal fluid is displaced immediately after pneumatic retinopexy with a small gas bubble injection in the vitreous cavity for superior rhegmatogenous retinal detachment. This series highlights the significant impact of the buoyant force applied to the detached retina by intravitreal gas in achieving retinal reattachment.
3 citations
TL;DR: In this paper , an alginate/Pluronic F127 based bio-ink for human dopaminergic brain tissue printing with tetrapodal-shaped-ZnO microparticles (t-ZNO) additive as the DA sensor was developed.
3 citations
TL;DR: Lawler et al. as discussed by the authors proposed a model for evidence generation during the COVID-19 Pandemic: New Opportunities for Clinical Trials in Cardiovascular Medicine No AccessArticle CommentaryRequest AccessFull TextAboutView Full TextView PDFView EPUBSections ToolsAdd to favoritesDownload citationsTrack citationsPermissions Share onFacebookTwitterLinked InMendeleyReddit Jump toNo AccessArticle commentaryRequest Access
Abstract: HomeCirculationVol. 147, No. 3Models for Evidence Generation During the COVID-19 Pandemic: New Opportunities for Clinical Trials in Cardiovascular Medicine No AccessArticle CommentaryRequest AccessFull TextAboutView Full TextView PDFView EPUBSections ToolsAdd to favoritesDownload citationsTrack citationsPermissions ShareShare onFacebookTwitterLinked InMendeleyReddit Jump toNo AccessArticle CommentaryRequest AccessFull TextModels for Evidence Generation During the COVID-19 Pandemic: New Opportunities for Clinical Trials in Cardiovascular Medicine Patrick R. Lawler, MD, MPH Patrick R. LawlerPatrick R. Lawler Correspondence to: Patrick R. Lawler, MD, MPH, Peter Munk Cardiac Center, Toronto General Hospital, RFE3-410, 190 Elizabeth St, Toronto, ON, Canada M5G 2C4. Email: E-mail Address: [email protected] https://orcid.org/0000-0001-5155-5071 Peter Munk Cardiac Centre, Toronto General Hospital; and Division of Cardiology and Interdepartmental Division of Critical Care Medicine, University of Toronto, Canada. Search for more papers by this author Originally published17 Jan 2023https://doi.org/10.1161/CIRCULATIONAHA.122.061231Circulation. 2023;147:187–189FootnotesThe opinions expressed in this article are not necessarily those of the editors or of the American Heart Association.Circulation is available at www.ahajournals.org/journal/circFor Sources of Funding and Disclosures, see page 189.Correspondence to: Patrick R. Lawler, MD, MPH, Peter Munk Cardiac Center, Toronto General Hospital, RFE3-410, 190 Elizabeth St, Toronto, ON, Canada M5G 2C4. Email: patrick.[email protected]caReferences1. Libby P. The changing landscape of atherosclerosis.Nature. 2021; 592:524–533. doi: 10.1038/s41586-021-03392-8CrossrefMedlineGoogle Scholar2. Lawler PR, Hochman JS, Zarychanski R. What are adaptive platform clinical trials and what role may they have in cardiovascular medicine?Circulation. 2022; 145:629–632. doi: 10.1161/circulationaha.121.058113LinkGoogle Scholar3. Park JJH, Detry MA, Murthy S, Guyatt G, Mills EJ. How to use and interpret the results of a platform trial: users’ guide to the medical literature.JAMA. 2022; 327:67–74. doi: 10.1001/jama.2021.22507CrossrefMedlineGoogle Scholar4. Dodd LE, Freidlin B, Korn EL. Platform trials - beware the noncomparable control group.N Engl J Med. 2021; 384:1572–1573. doi: 10.1056/NEJMc2102446CrossrefMedlineGoogle Scholar5. ATTACC Investigators, ACTIV-4a Investigators, REMAP-CAP Investigators. Therapeutic anticoagulation with heparin in noncritically ill patients with COVID-19.N Engl J Med. 2021; 385:790–802. doi: 10.1056/NEJMoa2105911CrossrefMedlineGoogle Scholar Previous Back to top Next FiguresReferencesRelatedDetails January 17, 2023Vol 147, Issue 3 Advertisement Article InformationMetrics © 2023 American Heart Association, Inc.https://doi.org/10.1161/CIRCULATIONAHA.122.061231PMID: 36649393 Originally publishedJanuary 17, 2023 Keywordsclinical trialpandemicsCOVID-19PDF download Advertisement SubjectsClinical Studies
TL;DR: In this paper , an impact assessment of upgrades to both the ICESat-2 freeboard data (ATL10) and NASA Eulerian Snow On Sea Ice Model (NESOSIM) snow loading on estimates of winter Arctic sea ice thickness is provided.
Abstract: Abstract. NASA's ICESat-2 mission has provided near-continuous, high-resolution estimates of sea ice freeboard across both hemispheres since data collection started in October 2018. This study provides an impact assessment of upgrades to both the ICESat-2 freeboard data (ATL10) and NASA Eulerian Snow On Sea Ice Model (NESOSIM) snow loading on estimates of winter Arctic sea ice thickness. Misclassified leads were removed from the freeboard algorithm in the third release (rel003) of ATL10, which generally results in an increase in freeboards compared to rel002 data. The thickness increases due to increased freeboards in ATL10 improved comparisons of Inner Arctic Ocean sea ice thickness with thickness estimates from ESA's CryoSat-2. The upgrade from NESOSIM v1.0 to v1.1 results in only small changes in snow depth and density which have a less significant impact on thickness compared to the rel002 to rel003 ATL10 freeboard changes. The updated monthly gridded thickness data are validated against ice draft measurements obtained by upward-looking sonar moorings deployed in the Beaufort Sea, showing strong agreement (r2 of 0.87, differences of 11 ± 20 cm). The seasonal cycle in winter monthly mean Arctic sea ice thickness shows good agreement with various CryoSat-2 products (and a merged ICESat-2–CryoSat-2 product) and PIOMAS (Pan-Arctic Ice-Ocean Modeling and Assimilation System). Finally, changes in Arctic sea ice conditions over the past three winter seasons of data collection (November 2018–April 2021) are presented and discussed, including a 50 cm decline in multiyear ice thickness and negligible interannual differences in first-year ice. Interannual changes in snow depth provide a notable impact on the thickness retrievals on regional and seasonal scales. Our monthly gridded thickness analysis is provided online in a Jupyter Book format to increase transparency and user engagement with our ICESat-2 winter Arctic sea ice thickness data.
TL;DR: In this paper , the authors examined variability in material use in single-family dwellings within and between three different locations (Toronto, Perth, and Luzon) and investigated how the use of different functional units changes the perception of what buildings are more materially efficient and which location has the more material efficient home building norms.
Abstract: This study examines variability in material use in single-family dwellings within and between three different locations (Toronto, Perth, and Luzon). It investigates how the use of different functional units changes the perception of what buildings are more materially efficient and which location has the more materially efficient home building norms. Material intensities for 80 single- family dwellings in the three locations form the foundational data for the paper. Important variabilities exist in the material intensities of the single-family dwellings and change with the functional unit selected (e.g., 7–23% for 1 m2 functional unit). Toronto single-family dwellings appear to be one of the least material intensive when presented per 1 m2 floor area but become the most material intensive when presented per 1 building and 1 bedroom with the opposite for Luzon. Housing size is the most effective explainer of overall material use with foundations and walls consuming the most materials but in different ratios across the three locations.
TL;DR: In this article , an inlet selection algorithm is presented, where the local saturation of the overall substrate, channel region, and land region match the prescribed input values within a tolerance of 2% absolute error.
TL;DR: In this paper , the authors examined how new telemedicine competitors affected incumbent health care providers during the first waves of COVID-19 and found that higher-quality providers are more likely to stop income-based discounts when facing new tele-medicINE entrants, while lower-quality ones are less likely to exit the platform, consistent with tele-medical providers competing for more price sensitive patients.
TL;DR: The authors investigated the effects of financial reporting on current employee job search and found that job search by current employees increases significantly during EA weeks, especially when employees are more mobile and when their information frictions are greater.
Abstract: We investigate the effects of financial reporting on current employee job search, that is, whether firms' public financial reports cause their employees to reevaluate their jobs and consider leaving. We develop theory for why current employees use earnings announcements (EAs) to inform job search decisions, and empirically investigate job search based on employees' activity on a popular job market website. We find that job search by current employees increases significantly during EA weeks, especially when employees are more mobile and when their information frictions are greater. We also find that employees use EAs to update their expectations about their employers' economic prospects, consistent with learning, and some evidence that positive announcements elicit less search. Our paper contributes to the burgeoning labor and accounting literature by providing among the first evidence closely linking financial reports to employee learning and job search.
TL;DR: In this paper , a cutoff of <4 or >4 CTCs as the optimal prognostic threshold for stage IB LUAD was generated to stratify the patients in a 70-patient cohort into low risk and high risk groups.
Abstract: Objective: To investigate the effectiveness of a CTC-based classifier in stratifying stage IB LUAD. Summary of Background Data: Stage IB LUADs have an approximately 70% 5-year survival rate. The clinical application of ACT is controversial due to inconsistent results in a series of trials and few useful guide biomarkers. Thus, there is a pressing need for robust biomarkers to stratify stage IB patients to define which group would most likely benefit from ACT. Methods: Two hundred twelve stage IB LUAD patients were enrolled and were divided into 3 independent cohorts. The aptamer-modified NanoVelcro system was used to enrich the CTCs. Results: A cutoff of <4 or >4 CTCs as the optimal prognostic threshold for stage IB LUAD was generated to stratify the patients in a 70-patient cohort into low-risk and high-risk groups. Patients with ≥ 4 CTCs in the training cohort had shorter progression-free survival (P < 0.0001) and overall survival (P < 0.0001) than patients with <4 CTCs. CTC number remained the strongest predictor of progression-free survival and overall survival even in a multivariate analysis including other clinicopathological parameters. Furthermore, a nomogram based on the CTC count was developed to predict the 3-year and 5-year survival in the training cohort and performed well in the other 2 validation cohorts (C-index: 0.862, 0.853, and 0.877). Conclusion: The presence of >4 CTCs can define a high-risk subgroup, providing a new strategy to make optimal clinical decisions for stage IB LUAD.
TL;DR: In this article , the effect of varying ionomer and iridium oxide material mass fractions on ion and electron transport properties is explored, and it is additionally recommended that both α pore and β pore regions must be incorporated into catalyst layer designs to allow both enhanced connectivity and mass transport characteristics.
20 Jan 2023
TL;DR: Skani as discussed by the authors is a method for calculating average nucleotide identity (ANI) using sparse approximate alignments, which is more accurate than FastANI for comparing incomplete, fragmented MAGs while also being 20 times faster.
Abstract: Abstract Sequence comparison algorithms for metagenome-assembled genomes (MAGs) often have difficulties dealing with data that is high-volume or low-quality. We present skani ( https://github.com/bluenote-1577/skani ), a method for calculating average nucleotide identity (ANI) using sparse approximate alignments. skani is more accurate than FastANI for comparing incomplete, fragmented MAGs while also being > 20 times faster. For searching a database of > 65, 000 prokaryotic genomes, skani takes only seconds per query and 6 GB of memory. skani is a versatile tool that unlocks higher-resolution insights for larger, noisier metagenomic data sets.
TL;DR: In this paper , the authors proposed the use of Silver nanoparticles (AgNPs) for root canal disinfection, mainly due to their wide-spectrum anti-microbial activity.
Abstract: The efficient elimination of microorganisms and their byproducts from infected root canals is compromised by the limitations in conventional root canal disinfection strategies and antimicrobials. Silver nanoparticles (AgNPs) are advantageous for root canal disinfection, mainly due to their wide-spectrum anti-microbial activity. Compared to other commonly used nanoparticulate antibacterials, AgNPs have acceptable antibacterial properties and relatively low cytotoxicity. Owing to their nano-scale, AgNPs penetrate deeper into the complexities of the root canal systems and dentinal tubules, as well as enhancing the antibacterial properties of endodontic irrigants and sealers. AgNPs gradually increase the dentin hardness in endodontically treated teeth and promote antibacterial properties when used as a carrier for intracanal medication. The unique properties of AgNPs make them an ideal additive for different endodontic biomaterials. However, the possible side effects of AgNPs, such as cytotoxicity and tooth discoloration potential, merits further research.
TL;DR: In this paper , a systematic search was performed to determine differences in long-term kidney and bladder outcomes in boys with posterior urethral valves (PUV) managed by a primary valve ablation or primary urinary diversion.
TL;DR: Culture safety training (CST) is often promoted as a key strategy to address anti-Indigenous racism in health and education systems in English-speaking colonized countries as discussed by the authors .
Abstract: Anti-Indigenous racism is a widespread social problem in health and education systems in English-speaking colonized countries. Cultural safety training (CST) is often promoted as a key strategy to address this problem, yet little evidence exists on how CST is operationalized and evaluated in health and education systems. This scoping review sought to broadly synthesize the academic literature on how CST programs are developed, implemented, and evaluated in the applied health, social work and education fields in Canada, United States, Australia, and New Zealand. MEDLINE, EMBASE, CINAHL, ERIC, and ASSIA were searched for articles published between 1996 and 2020. The Joanna Briggs Institute's three-step search strategy and PRISMA extension for scoping reviews were adopted, with 134 articles included. CST programs have grown significantly in the health, social work, and education fields in the last three decades, and they vary significantly in their objectives, modalities, timelines, and how they are evaluated. The involvement of Indigenous peoples in CST programs is common, but their roles are rarely specified. Indigenous groups must be intentionally and meaningfully engaged throughout the entire duration of research and practice. Cultural safety and various related concepts should be careful considered and applied for the relevant context.
20 Jan 2023
TL;DR: In this paper , the authors describe the clinical use and tolerability of immune checkpoint inhibitors in older adults with solid tumors, where there is an abundance of evidence with recent updates including subgroups of older patients.
Abstract: The aim of this review is to describe the clinical use and tolerability of immune checkpoint inhibitors in older adults with solid tumors, where there is an abundance of evidence with recent updates including subgroups of older patients.Studies with updated analyses and subgroups of older patients show that in general older patients benefit as well as younger patients and tolerate immunotherapy very well. However, in some instances of combination therapies which may expose patients to more toxicity, the benefits are reduced, and careful selection of older patients, including adjunctive assessments such as geriatric assessment, can help to identify the appropriate treatment for an individual patient.Older adults remain underrepresented in clinical trials, including those involving immunotherapy. Therefore, efforts must be made to include more older patients in trials and to assess real-world evidence to inform decision-making.
05 Jan 2023
TL;DR: In this paper , the authors discuss how viroids can hijack host cells and perform multiplication, even though they encode no proteins to achieve this, and what advantages do they have from their simplicity.
Abstract: Viroids represent the simplest, but are also among the most interesting life-like forms. They represent a great problem in agriculture. Moreover, pathogens similar to viroids, such as the hepatitis Delta virus represent a risk for human health. Viroids encode no proteins, but are still able to hijack their host cells’ metabolism to perform multiplication. This paper attempts to reply three questions about viroids. First, how can viroids hijack their host cells’ metabolism, even though they encode no proteins to achieve this? Second, what advantages do viroids have from their simplicity? Third, what can viroids, as the simplest life-like forms, tell us about life as a natural phenomenon? These questions are discussed from the perspective of biothermodynamics. In order to do this, elemental composition, biosynthesis reactions and standard thermodynamic properties of viroids have been determined and analyzed.
TL;DR: In this article , the authors investigated the process of the Joule-Thomson adiabatic expansion within rational NED-AdS spacetime, and the isenthalpic $$P{-}T$$ diagrams and the inversion temperature were depicted.
Abstract: The process of the Joule–Thomson adiabatic expansion within rational NED (RNED)-AdS spacetime is investigated. The isenthalpic $$P{-}T$$ diagrams and the inversion temperature are depicted. The inversion temperature depends on the magnetic charge and RNED coupling constant of black holes. When the Joule–Thomson coefficient vanishes, a cooling-heating phase transition occurs. We consider the cosmological constant as a thermodynamic pressure, and the black hole mass is treated as chemical enthalpy.
TL;DR: In this article , multiple typical AR coated commercial solar glass specimens from various manufacturers were characterized in terms of their optical property, abrasion resistance and outdoor reliability, and double-layer dense ARCs were investigated for boosting durability as well as maintaining a reasonable optical enhancement compared to single-layer ARC.
TL;DR: In this paper , a literature review indicates that AI tools can be used to support SPC clinicians in decision-making and reduce manual workload, leading to potentially improved care and outcomes for cancer patients.
Abstract: Artificial intelligence (AI) is a transformative technology that has the potential to improve and augment the clinical workflow in supportive and palliative care (SPC). The objective of this study was to provide an overview of the recent studies applying AI to SPC in cancer patients.Between 2020 and 2022, 29 relevant studies were identified and categorized into two applications: predictive modeling and text screening. Predictive modeling uses machine learning and/or deep learning algorithms to make predictions regarding clinical outcomes. Most studies focused on predicting short-term mortality risk or survival within 6 months, while others used models to predict complications in patients receiving treatment and forecast the need for SPC services. Text screening typically uses natural language processing (NLP) to identify specific keywords, phrases, or documents from patient notes. Various applications of NLP were found, including the classification of symptom severity, identifying patients without documentation related to advance care planning, and monitoring online support group chat data.This literature review indicates that AI tools can be used to support SPC clinicians in decision-making and reduce manual workload, leading to potentially improved care and outcomes for cancer patients. Emerging data from prospective studies supports the clinical benefit of these tools; however, more rigorous clinical validation is required before AI is routinely adopted in the SPC clinical workflow.
TL;DR: In this paper , the authors explored the therapeutic potential of a thermosensitive liposome formulation of the commonly used chemotherapy drug vinorelbine in combination with mild hyperthermia (39-43 °C) in a murine model of rhabdomyosarcoma.
01 Jan 2023
TL;DR: In this paper , the authors determined the relationship between surgeon opioid prescribing intensity and subsequent persistent opioid use among patients undergoing surgery and found that patients with surgeons in the highest intensity quartile were more likely to fill an opioid prescription within 7 days after surgery compared with those in the lowest quartile (Q1) (83.3% vs 65.4% Q1).
Abstract: The aim of this study was to determine the relationship between surgeon opioid prescribing intensity and subsequent persistent opioid use among patients undergoing surgery.The extent to which different postoperative prescribing practices lead to persistent opioid use among surgical patients is poorly understood.Retrospective population-based cohort study assessing opioid-naive adults who underwent one of four common surgeries. For each surgical procedure, the surgeons' opioid prescribing intensity was categorized into quartiles based on the median daily dose of morphine equivalents of opioids dispensed within 7 days of the surgical visit for all the surgeons' patients. The primary outcome was persistent opioid use in the year following surgery, defined as 180 days or more of opioids supplied within the year after the index date excluding prescriptions filled within 30 days of the index date. Secondary outcomes included a refill for an opioid within 30 days and emergency department visits and hospitalizations within 1 year.Among 112,744 surgical patients, patients with surgeons in the highest intensity quartile (Q4) were more likely to fill an opioid prescription within 7 days after surgery compared with those in the lowest quartile (Q1) (83.3% Q4 vs 65.4% Q1). In the primary analysis, the incidence of persistent opioid use in the year after surgery was rare in both highest and lowest quartiles (0.3% Q4 vs 0.3% Q1), adjusted odds ratio (AOR) of 1.18, 95% CI 0.83-1.66). However, multiple analyses using stricter definitions of persistent use that included the requirement of a prescription filled within 7 days of discharge after surgery showed a significant association with surgeon quartile (up to an AOR 1.36, 95% CI 1.25, 1.47). Patients in Q4 were more likely to refill a prescription within 30 days (4.8% Q4 vs 4.0% Q1, AOR 1.14, 95% CI 1.04-1.24).Surgeons' overall prescribing practices may contribute to persistent opioid use and represent a target for quality improvement. However, the association was highly sensitive to the definition of persistent use used.