University of Calgary

About: University of Calgary is a education organization based out in Calgary, Alberta, Canada. It is known for research contribution in the topics: Population & Health care. The organization has 44284 authors who have published 104970 publications receiving 3669161 citations. The organization is also known as: U of C & UCalgary.

Crude-oil biodegradation via methanogenesis in subsurface petroleum reservoirs

Abstract: Biodegradation of crude oil in subsurface petroleum reservoirs has adversely affected the majority of the world's oil, making recovery and refining of that oil more costly. The prevalent occurrence of biodegradation in shallow subsurface petroleum reservoirs has been attributed to aerobic bacterial hydrocarbon degradation stimulated by surface recharge of oxygen-bearing meteoric waters. This hypothesis is empirically supported by the likelihood of encountering biodegraded oils at higher levels of degradation in reservoirs near the surface. More recent findings, however, suggest that anaerobic degradation processes dominate subsurface sedimentary environments, despite slow reaction kinetics and uncertainty as to the actual degradation pathways occurring in oil reservoirs. Here we use laboratory experiments in microcosms monitoring the hydrocarbon composition of degraded oils and generated gases, together with the carbon isotopic compositions of gas and oil samples taken at wellheads and a Rayleigh isotope fractionation box model, to elucidate the probable mechanisms of hydrocarbon degradation in reservoirs. We find that crude-oil hydrocarbon degradation under methanogenic conditions in the laboratory mimics the characteristic sequential removal of compound classes seen in reservoir-degraded petroleum. The initial preferential removal of n-alkanes generates close to stoichiometric amounts of methane, principally by hydrogenotrophic methanogenesis. Our data imply a common methanogenic biodegradation mechanism in subsurface degraded oil reservoirs, resulting in consistent patterns of hydrocarbon alteration, and the common association of dry gas with severely degraded oils observed worldwide. Energy recovery from oilfields in the form of methane, based on accelerating natural methanogenic biodegradation, may offer a route to economic production of difficult-to-recover energy from oilfields.

Effect of alcohol consumption on biological markers associated with risk of coronary heart disease: systematic review and meta-analysis of interventional studies

Abstract: Objective To systematically review interventional studies of the effects of alcohol consumption on 21 biological markers associated with risk of coronary heart disease in adults without known cardiovascular disease. Design Systematic review and meta-analysis. Data sources Medline (1950 to October 2009) and Embase (1980 to October 2009) without limits. Study selection Two reviewers independently selected studies that examined adults without known cardiovascular disease and that compared fasting levels of specific biological markers associated with coronary heart disease after alcohol use with those after a period of no alcohol use (controls). 4690 articles were screened for eligibility, the full texts of 124 studies reviewed, and 63 relevant articles selected. Results Of 63 eligible studies, 44 on 13 biomarkers were meta-analysed in fixed or random effects models. Quality was assessed by sensitivity analysis of studies grouped by design. Analyses were stratified by type of beverage (wine, beer, spirits). Alcohol significantly increased levels of high density lipoprotein cholesterol (pooled mean difference 0.094 mmol/L, 95% confidence interval 0.064 to 0.123), apolipoprotein A1 (0.101 g/L, 0.073 to 0.129), and adiponectin (0.56 mg/L, 0.39 to 0.72). Alcohol showed a dose-response relation with high density lipoprotein cholesterol (test for trend P=0.013). Alcohol decreased fibrinogen levels (−0.20 g/L, −0.29 to −0.11) but did not affect triglyceride levels. Results were similar for crossover and before and after studies, and across beverage types. Conclusions Favourable changes in several cardiovascular biomarkers (higher levels of high density lipoprotein cholesterol and adiponectin and lower levels of fibrinogen) provide indirect pathophysiological support for a protective effect of moderate alcohol use on coronary heart disease.

The Heidelberg Bleeding Classification: Classification of Bleeding Events After Ischemic Stroke and Reperfusion Therapy.

Abstract: Intracranial hemorrhage is an important safety end point in clinical trials.1–6 Yet, not each intracranial hemorrhage detected by computed tomography (CT) or magnetic resonance imaging (MRI) worsens neurological symptoms and impairs outcomes. Consequently, intracranial hemorrhages after ischemic stroke and reperfusion therapy are classified by both imaging characteristics and the association with clinical worsening. Pure radiological classification uses the location, form, and extent of hemorrhage and its relation to ischemic injury to distinguish among hemorrhage subtypes that may differ in impairment of neurological function and prognosis. Mixed radiological–clinical classification adds clinical symptoms to the presence of radiological hemorrhage to classify intracranial hemorrhages as symptomatic or asymptomatic. Historically, modern approaches to classifying hemorrhage after reperfusion therapy began with the emphasis of Pessin et al1 on the radiographic distinction between hemorrhagic infarction (HI) and parenchymatous hematoma (PH) after embolic stroke. They stated that HI refers to the pathological condition in which petechial or more confluent hemorrhages occupy a portion of an area of ischemic infarction. PH in an area of infarction; in contrast, is a solid clot of blood with mass effect, which displaces and destroys brain tissue.1 They later proposed that HI (in contrast to PH) could be more of a CT curiosity than a dreaded complication.2 Wolpert et al5 defined HI as areas of barely visible increased density with indistinct margins within an infarct or areas of increased density with indistinct margins and a speckled or mottled appearance or multiple areas of coalescent hemorrhage. A mass effect could be present because of the either edema or hemorrhagic component and PH (later named parenchymal hematoma3) and as very dense, homogenous region(s) of circumscribed increased density usually with mass effect. Both HI and PH are presumably caused by the same postischemic pathophysiology, bleeding from damaged …

Implementing patient-reported outcomes assessment in clinical practice: a review of the options and considerations

Abstract: While clinical care is frequently directed at making patients “feel better,” patients’ reports on their functioning and well-being (patient-reported outcomes [PROs]) are rarely collected in routine clinical practice. The International Society for Quality of Life Research (ISOQOL) has developed a User’s Guide for Implementing Patient-Reported Outcomes Assessment in Clinical Practice. This paper summarizes the key issues from the User’s Guide. Using the literature, an ISOQOL team outlined considerations for using PROs in clinical practice; options for designing the intervention; and strengths, weaknesses, and resource requirements associated with each option. Implementing routine PRO assessment involves a number of methodological and practical decisions, including (1) identifying the goals for collecting PROs in clinical practice, (2) selecting the patients, setting, and timing of assessments, (3) determining which questionnaire(s) to use, (4) choosing a mode for administering and scoring the questionnaire, (5) designing processes for reporting results, (6) identifying aids to facilitate score interpretation, (7) developing strategies for responding to issues identified by the questionnaires, and (8) evaluating the impact of the PRO intervention on the practice. Integrating PROs in clinical practice has the potential to enhance patient-centered care. The online version of the User’s Guide will be updated periodically.