Publications by authors named "Walters D"

Significant variation in mercury (Hg) bioaccumulation is observed across the diversity of freshwater ecosystems in North America. While there is support for the major drivers of Hg bioaccumulation, the relative influence of different external factors can vary widely among waterbodies, which makes predicting Hg risk across large spatial scales particularly challenging. We modeled Hg bioaccumulation by coupling Hg concentrations in more than 21,000 dragonflies collected across the United States from 2008 to 2021 with a suite of chemical (e.

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Historic copper mining left a legacy of metal-rich tailings resulting in ecological impacts along and within Torch Lake, an area of concern in the Keweenaw Peninsula, Michigan, USA. Given the toxicity of copper to invertebrates, this study assessed the influence of this legacy on present day nearshore aquatic and terrestrial ecosystems. We measured the metal (Co, Cu, Ni, Zn, Cd) and metalloid (As) concentrations in sediment, pore water, surface water, larval and adult insects, and two riparian spider taxa collected from Torch Lake and a nearby reference lake.

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Attempts to mitigate the computational cost of fully resolved large-eddy simulation (LES) in the near-wall region include both the hybrid Reynolds-averaged Navier-Stokes/LES (HRL) and wall-modeled LES (WMLES) approaches. This paper presents an LES wall treatment method that combines key attributes of the two, in which the boundary layer mesh is sized in the streamwise and spanwise directions comparable to WMLES, and the wall-normal mesh is comparable to a RANS simulation without wall functions. A mixing length model is used to prescribe an eddy viscosity in the near-wall region, with the mixing length scale limited based on local mesh size.

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Objective: Cannabis use has increased in the United States as states have legalized/decriminalized recreational and/or medicinal use. The primary aim of this study was to examine daily associations between cannabis use and health (physical activity [PA]) and substance use (alcohol consumption, cigarette use) behaviors.

Method: Data from a 28-day nationwide study that prompted daily ecological momentary assessments (EMAs) were used to assess daily cannabis use, moderate-to-vigorous PA (MVPA), alcohol containing drinks consumed, and cigarettes smoked.

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Cancer ablation with pulsed electric fields (PEFs) involves the delivery of high-voltage, short-duration electrical pulses that destabilize tumor cells, leading to cellular death. Unlike most conventional ablation technologies, PEF ablation is non-thermal, allowing for safe and targeted energy delivery to the tumor without damaging surrounding tissue and critical structures. PEFs allow for specific dosing, predictable treatment zones, and preservation of the extracellular matrix and adjacent vascular tissues.

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The movement of large amounts of nutrients by migrating animals has ecological benefits for recipient food webs that may be offset by co-transported contaminants. Salmon spawning migrations are archetypal of this process, carrying marine-derived materials to inland ecosystems where they stimulate local productivity but also enhance contaminant exposure. Pacific salmon abundance and biomass are higher now than in the last century, reflecting substantial shifts in community structure that probably altered nutrient versus contaminant delivery.

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Herein, we present a protocol for culturing patient-derived organoids (PDOs) of cervical cancer that includes workflows for tumor biopsy/resection tissue and cytobrush-sampled cells. We describe steps for PDO culture initiation, including rinsing, gentle dissociation, Lymphoprep separation, and cell assessment, as well as seeding cells from surgical and cytobrush tissue digestion. We then provide guidance on PDO maintenance and passage and techniques for producing conditioned medium.

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 The well-documented relationship between mental health and substance use is corroborated by recent research on the impacts of the Covid-19 pandemic on cannabis use behavior. Social isolation, anxiety, depression, stress, and boredom are all linked to the greater prevalence of cannabis and other substance use. Objectives: To better understand the relationship between infection rates in Canada and cannabis use behavior, this research examines the prevalence and frequency of cannabis use across health regions in all 10 provinces at the height of the pandemic.

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Background: Historically, differences in timely reperfusion and outcomes have been described in females who suffer ST-segment elevation myocardial infarction (STEMI). However, there have been improvements in the treatment of STEMI patients with contemporary Percutaneous Coronary Intervention (PCI) strategies.

Methods: Comparisons between sexes were performed on STEMI patients treated with primary PCI over a 4-year period (January 1, 2017-December 31, 2020) from the Queensland Cardiac Outcomes Registry.

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Introduction: The incidence of STEMI and subsequent mortality has been reported to be higher in Indian populations compared to developed countries. However, there is limited data directly comparing contemporary primary percutaneous coronary intervention (pPCI) treatment strategies and clinical outcomes for STEMI patients between developed and developing countries.

Materials And Methods: We compared population demographics, procedural characteristics, times to reperfusion and mortality in STEMI patients treated with pPCI between two tertiary referral centers in India and Australia respectively over a 3-year period (1st Jan 2017-31st Dec 2019).

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Ventilation-perfusion SPECT with or without CT using technetium 99m (Tc)-diethylenetriaminepentaacetic acid (DTPA) has been used to identify patterns typical of cardiopulmonary diseases, such as pulmonary embolism, pneumonia, heart failure, and obstructive lung disease. This case demonstrates the utility of a ventilation scan with SPECT/CT using Tc-DTPA for investigating the cause of a persistent complex pneumothorax in a patient with severe chronic obstructive pulmonary disease who recently underwent endobronchial valve placement. CT-Spectral Imaging (Multienergy), SPECT/CT, Thorax, Lung © RSNA, 2024.

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Hematopoietic and stromal cells within the bone marrow (BM) provide membrane-bound and/or soluble factors that are vital for the survival of plasma cells (PCs). Recent reports in murine BM demonstrated the dynamic formation and dispersion of PC clusters. To date, PC clustering in normal human BM has yet to be thoroughly examined.

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At present, the world is off-track to meet the World Health Assembly global nutrition targets for 2025. Reducing the prevalence of stunting and low birthweight (LBW) in children, and anaemia in women, and increasing breastfeeding rates are among the prioritized global nutrition targets for all countries. Governments and development partners need evidence-based data to understand the true costs and consequences of policy decisions and investments.

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Atmospheric mercury (Hg) emissions and subsequent transport and deposition are major concerns within protected lands, including national parks, where Hg can bioaccumulate to levels detrimental to human and wildlife health. Despite this risk to biological resources, there is limited understanding of the relative importance of different Hg sources and delivery pathways within the protected regions. Here, we used Hg stable isotope measurements within a single aquatic bioindicator, dragonfly larvae, to determine if these tracers can resolve spatial patterns in Hg sources, delivery mechanisms, and aquatic cycling at a national scale.

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Research has linked disability to differential experiences and outcomes for students at multiple levels of education. To date, however, available data sources have prevented comprehensive analyses of the statistical relationship between disability and the pathways traveled by students through Ontario post-secondary education (PSE). Through this study, we examine this topic by leveraging a large multifaceted linkage that brings together rich administrative data from the Toronto District School Board (Grades 9-12), Ontario college and university enrollment records (2009-2018), as well as government student loans and tax records.

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As cardiothoracic surgeons, we face frequent challenges to our well-being and our ability to function as our best selves. Building personal resilience is an important way to help us manage these challenges. Here, the authors outline the scope of the problem, the consequences of burnout, and offer 4 strategies to train ourselves to be more resilient: (1) Pursuit of fulfillment, (2) Cultivation of community and belonging, (3) Mitigation of microstresses and avoiding feelings of overwhelm, and (4) Building a "resilience bank account.

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Objective: The purpose of this study was to examine the likelihood of driving after using cannabis, and of being a passenger with someone who is driving after using cannabis, in rural areas and non-rural areas before and after legalization.

Methods: A multi-wave analysis of Canada's National Cannabis Survey was conducted using logistic regression with interactions to predict the prevalence of driving after using cannabis, and of being a passenger with someone who is driving after using cannabis, in relation to place of residence (rural or non-rural) and in the weeks and months before and after legalization. Three time points were compared: pre-legalization, two months following legalization and 1 year after legalization.

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Evidence is steadily mounting that attribute-based models offer a more accurate description of intertemporal choices than traditional alternative-based models. Among the attribute-based models, the tradeoff model offers the broadest coverage of research findings, but at the cost of considerable complexity: There now are various instantiations of the model dealing with partially overlapping universes of choice options and preference patterns. Moreover, there are reports of preference patterns in intertemporal decisions about monetary losses that contradict all attribute-based models proposed so far.

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Tetragnathid spiders have been used as sentinels to study the biotransport of contaminants between aquatic and terrestrial environments because a significant proportion of their diet consists of adult aquatic insects. A key knowledge gap in assessing tetragnathid spiders as sentinels is understanding the consistency of the year-to-year relationship between contaminant concentrations in spiders and sediment, water, and macroinvertebrates. We collected five years of data over a seven-year investigation at a PCB contaminated-sediment site to investigate if concentrations in spiders were consistently correlated with concentrations in sediment, water, and aquatic macroinvertebrates.

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Thiamine (vitamin B) is required by all living organisms in multiple metabolic pathways. It is scarce in natural systems, and deficiency can lead to reproductive failure, neurological issues, and death. One major cause of thiamine deficiency is an overreliance on diet items containing the enzyme thiaminase.

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Streamflow-duration assessment methods (SDAMs) are rapid, indicator-based tools for classifying streamflow duration (e.g., intermittent vs perennial flow) at the reach scale.

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Article Synopsis
  • The study investigates how aquatic contaminants, particularly mercury (Hg), transfer from water to land ecosystems, with a focus on shoreline spiders as indicators of this transfer.
  • Researchers collected samples from various habitats along the St. Louis and Bad Rivers to measure mercury levels in spiders and aquatic insects, finding strong correlations in mercury signatures between these organisms.
  • The findings emphasize that different spider species exhibit varying mercury isotope ratios based on their feeding habits, suggesting that selecting specific spider taxa is crucial for effective monitoring of mercury contamination.
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Interstitial lung diseases (ILDs) are lethal lung diseases characterized by pulmonary inflammation and progressive lung interstitial scarring. We previously developed a mouse model of ILD using vanadium pentoxide (VO) and identified several gene candidates on chromosome 4 associated with pulmonary fibrosis. While these data indicated a significant genetic contribution to ILD susceptibility, they did not include any potential associations and interactions with the mitochondrial genome that might influence disease risk.

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