1,721,012 research outputs found
The effect of low and high-intensity cycling in diesel exhaust on flow-mediated dilation, circulating NOx, endothelin-1 and blood pressure
Get PDFINTRODUCTION:
Exposure to air pollution impairs aspects of endothelial function such as flow-mediated dilation (FMD). Outdoor exercisers are frequently exposed to air pollution, but how exercising in air pollution affects endothelial function and how these effects are modified by exercise intensity are poorly understood.
OBJECTIVES:
Therefore, the purpose of this study was to determine the effects of low-intensity and high-intensity cycling with diesel exhaust (DE) exposure on FMD, blood pressure, plasma nitrite and nitrate (NOx) and endothelin-1.
METHODS:
Eighteen males performed 30-minute trials of low or high-intensity cycling (30% and 60% of power at VO2peak) or a resting control condition. For each subject, each trial was performed once while breathing filtered air (FA) and once while breathing DE (300ug/m3 of PM2.5, six trials in total). Preceding exposure, immediately post-exposure, 1 hour and 2 hours post-exposure, FMD, blood pressure and plasma endothelin-1 and NOx concentrations were measured. Data were analyzed using repeated-measures ANOVA and linear mixed model.
RESULTS:
Following exercise in DE, plasma NOx significantly increased and was significantly greater than FA (p<0.05). Two hours following DE exposure, endothelin-1 was significantly less than FA (p = 0.037) but exercise intensity did not modify this response. DE exposure did not affect FMD or blood pressure.
CONCLUSION:
Our results suggest that exercising in DE did not adversely affect plasma NOX, endothelin-1, FMD and blood pressure. Therefore, recommendations for healthy individuals to moderate or avoid exercise during bouts of high pollution appear to have no acute protective effect.Peer reviewedFinal article published
Effects of low-intensity and high-intensity cycling with diesel exhaust exposure on soluble P-selectin, E-selectin, I-CAM-1, VCAM-1 and complete blood count
Get PDFBackground: Exposure to particulate matter 2.5 μm or less (PM2.5) that contains transition metals may play a role in systemic oxidative stress and inflammation. Exposure to diesel exhaust (DE) can increase adhesion molecules, which are important in the inflammatory response; however, it is unclear how exercising in DE affects adhesion molecules and how exercise intensity modulates this response.
Aim: To determine how DE exposure during exercise of varying intensities affects adhesion molecules and markers of systemic inflammation.
Methods: Eighteen males performed 30 min cycling bouts at low intensity and high intensity (30% and 60% of power at VO2peak (peak oxygen consumption) and a control condition (rest)). Each trial was performed once breathing filtered air (FA) and once breathing DE (300 μg/m3 of PM2.5, six trials in total). Prior to, immediately post, 1 and 2 hours post exposure, blood was drawn to measure parameters of a complete blood count and soluble (s) platelet-Selectin, endothelin-Selectin, intracellular cell adhesion molecule (sICAM)-1 and vascular cell adhesion molecule (sVCAM)-1. Data were analysed using repeated-measures analysis of variance.
Results: Two hours following high-intensity exercise, sICAM-1 was significantly less in DE compared with FA (p=0.008). Immediately following rest (p=0.013) and high-intensity exercise (p=0.042) in DE, sICAM-1 was significantly greater than immediately following low-intensity exercise in DE. There were no significant differences in other markers between DE and FA.
Conclusions: Based on this study, healthy individuals may not experience an acute increase in adhesion molecules and systemic inflammatory markers from exercising in DE compared with FA, and higher exercise intensities do not appear to increase the likelihood that DE will affect adhesion molecules and systemic inflammatory markers.Peer reviewedFinal article published.adhesion moleculesair pollutionexerciseexercise intensityinflammator
A comprehensive analysis of the transcriptomic landscape of interstitial lung diseases
No full textFibrotic interstitial lung disease (ILD) comprises a heterogeneous group of >200 disorders that are common in older adults and characterized by excessive deposition of fibrous tissue in the lung interstitium, resulting in decreased blood uptake of oxygen. A critical aspect of ILD research that must be addressed is the difficulty in correctly diagnosing specific ILD subtypes, especially when differentiating between common subtypes such as idiopathic pulmonary fibrosis (IPF) and hypersensitivity pneumonitis (HP). IPF requires different pharmacotherapy compared to non-IPF ILDs, but IPF is difficult to conclusively diagnose due to non-specific radiological patterns and risks associated with histopathological lung biopsies. Additionally, certain ILD subtypes present with rapid decline in lung function known as progressive pulmonary fibrosis (PPF), and little is known about the biology behind this phenotype. Given the risk of mortality associated with lung biopsies in older adults, peripheral blood biomarkers are an attractive medium of investigation.
The objective of this thesis was to investigate the peripheral transcriptome (gene expression) for biomarkers of ILD diagnosis and progression. To establish a baseline of changes in gene expression in ILD, I performed a systematic review and meta-analysis of the bulk ILD transcriptome in both lung and blood samples, and identified unique and shared pathways between ILD subtypes. Through an unsupervised analysis, molecular endotypes of various disease mechanisms were identified and associated with lung function. In a pilot study, the feasibility of using whole blood RNA to differentiate between ILD subtypes and relate their expression to the lung microenvironment was examined in a small cohort using a targeted gene expression assay, and I identified blood samples from systemic sclerosis-associated ILD (SSc-ILD) as differentially expressed from IPF and HP. This was confirmed in a study of ILD subtypes using whole genome sequencing, where a significant increase in interferon-associated genes and genes associated with progression were observed in SSc-ILD. Using ILD gene expression data, I further identified a model predicting survival which was validated on external IPF samples. Finally, cell-specific transcriptomic profiles were identified in IPF and HP using single cell RNA-sequencing, which were associated with previously identified fibrotic cell types in the lung.Medicine, Faculty ofMedicine, Department ofGraduat
Investigating early life immunity and vaccine response using high-dimensional biological (omics) datasets
No full textThe full abstract for this thesis is available in the body of the thesis, and will be available when the embargo expires.Medicine, Faculty ofMedicine, Department ofGraduat
Going Beyond Counting First Authors in Author Co-citation Analysis
Get PDFThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
Variations on the Author
Get PDF“Variations on the Author” discusses two of Eduardo Coutinho’s recent films (Um Dia na Vida, from 2010, and Últimas Conversas, posthumously released in 2015) and their contribution to the general question of documentary authorship. The director’s filmography is characterized by a consistent yet self-effacing form of authorial self-inscription: Coutinho often features as an interviewer that rather than express opinions propels discourses; an interviewer that is good at listening. This mode of self-inscription characterizes him as an author who is not expressive but who is nonetheless markedly present on the screen. In Um Dia na Vida, however, Coutinho is completely absent form the image, while Últimas Conversas, on the contrary, includes a confessional prologue that moves the director from the margins to the center of his films. This article examines the ways in which these works stand out in the filmography of a director who offers new insights into the notion of cinematic authorship
Appropriate Similarity Measures for Author Cocitation Analysis
Get PDFWe provide a number of new insights into the methodological discussion about author cocitation analysis. We first argue that the use of the Pearson correlation for measuring the similarity between authors’ cocitation profiles is not very satisfactory. We then discuss what kind of similarity measures may be used as an alternative to the Pearson correlation. We consider three similarity measures in particular. One is the well-known cosine. The other two similarity measures have not been used before in the bibliometric literature. Finally, we show by means of an example that our findings have a high practical relevance.information science;Pearson correlation;cosine;similarity measure;author cocitation analysis
Dispelling the Myths Behind First-author Citation Counts
Get PDFWe conducted a full-scale evaluative citation analysis study of scholars in the XML research field to explore just how different from each other author rankings resulting from different citation counting methods actually are, and to demonstrate the capability of emerging data and tools on the Web in supporting more realistic citation counting methods. Our results contest some common arguments for the continued
use of first-author citation counts in the evaluation of scholars, such as high correlations between author rankings by first-author citation counts and other citation
counting methods, and high costs of using more realistic citation counting methods that are not well-supported by the ISI databases. It is argued that increasingly available digital full text research papers make it possible for citation analysis studies to go beyond what the ISI databases have directly supported and to employ more
sophisticated methods
- …
