McMaster University

About: McMaster University is a education organization based out in Hamilton, Ontario, Canada. It is known for research contribution in the topics: Population & Health care. The organization has 41361 authors who have published 101269 publications receiving 4251422 citations.

Pulmonary drug delivery. Part I: Physiological factors affecting therapeutic effectiveness of aerosolized medications

Abstract: As the end organ for the treatment of local diseases or as the route of administration for systemic therapies, the lung is a very attractive target for drug delivery. It provides direct access to disease in the treatment of respiratory diseases, while providing an enormous surface area and a relatively low enzymatic, controlled environment for systemic absorption of medications. As a major port of entry, the lung has evolved to prevent the invasion of unwanted airborne particles from entering into the body. Airway geometry, humidity, mucociliary clearance and alveolar macrophages play a vital role in maintaining the sterility of the lung and consequently are barriers to the therapeutic effectiveness of inhaled medications. In addition, a drug's efficacy may be affected by where in the respiratory tract it is deposited, its delivered dose and the disease it may be trying to treat.

Systems for grading the quality of evidence and the strength of recommendations I: critical appraisal of existing approaches The GRADE Working Group.

Abstract: A number of approaches have been used to grade levels of evidence and the strength of recommendations. The use of many different approaches detracts from one of the main reasons for having explicit approaches: to concisely characterise and communicate this information so that it can easily be understood and thereby help people make well-informed decisions. Our objective was to critically appraise six prominent systems for grading levels of evidence and the strength of recommendations as a basis for agreeing on characteristics of a common, sensible approach to grading levels of evidence and the strength of recommendations. Six prominent systems for grading levels of evidence and strength of recommendations were selected and someone familiar with each system prepared a description of each of these. Twelve assessors independently evaluated each system based on twelve criteria to assess the sensibility of the different approaches. Systems used by 51 organisations were compared with these six approaches. There was poor agreement about the sensibility of the six systems. Only one of the systems was suitable for all four types of questions we considered (effectiveness, harm, diagnosis and prognosis). None of the systems was considered usable for all of the target groups we considered (professionals, patients and policy makers). The raters found low reproducibility of judgements made using all six systems. Systems used by 51 organisations that sponsor clinical practice guidelines included a number of minor variations of the six systems that we critically appraised. All of the currently used approaches to grading levels of evidence and the strength of recommendations have important shortcomings.

Semantic Similarity Based on Corpus Statistics and Lexical Taxonomy

Abstract: This paper presents a new approach for measuring semantic similarity/distance between words and concepts. It combines a lexical taxonomy structure with corpus statistical information so that the semantic distance between nodes in the semantic space constructed by the taxonomy can be better quantified with the computational evidence derived from a distributional analysis of corpus data. Specifically, the proposed measure is a combined approach that inherits the edge-based approach of the edge counting scheme, which is then enhanced by the node-based approach of the information content calculation. When tested on a common data set of word pair similarity ratings, the proposed approach outperforms other computational models. It gives the highest correlation value (r = 0.828) with a benchmark based on human similarity judgements, whereas an upper bound (r = 0.885) is observed when human subjects replicate the same task.

An edge-guided image interpolation algorithm via directional filtering and data fusion

Abstract: Preserving edge structures is a challenge to image interpolation algorithms that reconstruct a high-resolution image from a low-resolution counterpart. We propose a new edge-guided nonlinear interpolation technique through directional filtering and data fusion. For a pixel to be interpolated, two observation sets are defined in two orthogonal directions, and each set produces an estimate of the pixel value. These directional estimates, modeled as different noisy measurements of the missing pixel are fused by the linear minimum mean square-error estimation (LMMSE) technique into a more robust estimate, using the statistics of the two observation sets. We also present a simplified version of the LMMSE-based interpolation algorithm to reduce computational cost without sacrificing much the interpolation performance. Experiments show that the new interpolation techniques can preserve edge sharpness and reduce ringing artifacts

Waist circumference and waist-to-hip ratio as predictors of cardiovascular events: meta-regression analysis of prospective studies

Abstract: Aims The objectives of this study were to determine the association of waist circumference (WC) and waist-to-hip ratio (WHR) with the risk of incident cardiovascular disease (CVD) events and to determine whether the strength of association of WC and WHR with CVD risk is different. Methods and results This meta-regression analysis used a search strategy of keywords and MeSH terms to identify prospective cohort studies and randomized clinical trials of CVD risk and abdominal obesity from the Medline, Embase, and Cochrane databases. Fifteen articles ( n = 258 114 participants, 4355 CVD events) reporting CVD risk by categorical and continuous measures of WC and WHR were included. For a 1 cm increase in WC, the relative risk (RR) of a CVD event increased by 2% (95% CI: 1–3%) overall after adjusting for age, cohort year, or treatment. For a 0.01 U increase in WHR, the RR increased by 5% (95% CI: 4–7%). These results were consistent in men and women. Overall risk estimates comparing the extreme quantiles of each measure suggested that WHR was more strongly associated with CVD than that for WC (WHR: RR = 1.95, 95% CI: 1.55–2.44; WC: RR = 1.63, 95% CI: 1.31–2.04), although this difference was not significant. The strength of association for each measure was similar in men and women. Conclusion WHR and WC are significantly associated with the risk of incident CVD events. These simple measures of abdominal obesity should be incorporated into CVD risk assessments.