39 research outputs found
The index lift in data mining has a close relationship with the association measure relative risk in epidemiological studies.
BACKGROUND: Data mining tools have been increasingly used in health research, with the promise of accelerating discoveries. Lift is a standard association metric in the data mining community. However, health researchers struggle with the interpretation of lift. As a result, dissemination of data mining results can be met with hesitation. The relative risk and odds ratio are standard association measures in the health domain, due to their straightforward interpretation and comparability across populations. We aimed to investigate the lift-relative risk and the lift-odds ratio relationships, and provide tools to convert lift to the relative risk and odds ratio. METHODS: We derived equations linking lift-relative risk and lift-odds ratio. We discussed how lift, relative risk, and odds ratio behave numerically with varying association strengths and exposure prevalence levels. The lift-relative risk relationship was further illustrated using a high-dimensional dataset which examines the association of exposure to airborne pollutants and adverse birth outcomes. We conducted spatial association rule mining using the Kingfisher algorithm, which identified association rules using its built-in lift metric. We directly estimated relative risks and odds ratios from 2 by 2 tables for each identified rule. These values were compared to the corresponding lift values, and relative risks and odds ratios were computed using the derived equations. RESULTS: As the exposure-outcome association strengthens, the odds ratio and relative risk move away from 1 faster numerically than lift, i.e. |log (odds ratio)| ≥ |log (relative risk)| ≥ |log (lift)|. In addition, lift is bounded by the smaller of the inverse probability of outcome or exposure, i.e. lift≤ min (1/P(O), 1/P(E)). Unlike the relative risk and odds ratio, lift depends on the exposure prevalence for fixed outcomes. For example, when an exposure A and a less prevalent exposure B have the same relative risk for an outcome, exposure A has a lower lift than B. CONCLUSIONS: Lift, relative risk, and odds ratio are positively correlated and share the same null value. However, lift depends on the exposure prevalence, and thus is not straightforward to interpret or to use to compare association strength. Tools are provided to obtain the relative risk and odds ratio from lift
Ambient Particulate Matter Induces Interleukin-8 Expression through an Alternative NF-κB (Nuclear Factor-Kappa B) Mechanism in Human Airway Epithelial Cells
Background: Exposure to ambient air particulate matter (PM) has been shown to increase rates of cardiopulmonary morbidity and mortality, but the underlying mechanisms are still not well understood
PIXE Analysis Of Atmospheric Aerosols Related To Their Cytotoxic And Genotoxic Effects
ABSTRACT Results are given of a study regarding the relationship of composition of airborne particles in Mexico City (PM 15 , PM 10 and PM 2.5 ) with citotoxic/genotoxic effects on cell cultures. Elemental analysis of samples collected during the first half of 2002 at three sites was carried out with PIXE, together with several citotoxic/genotoxic studies (generation of •OH, cellular death, inflammatory responses, and damage to cellular DNA). Differences were found in elemental contents in the aerosols from the three sites. The results suggest that some of the latter effects are correlated to higher concentrations of certain elements in the particles
An overview of the MILAGRO 2006 Campaign: Mexico City emissions and their transport and transformation
MILAGRO (Megacity Initiative: Local And Global Research Observations) is an international collaborative project to examine the behavior and the export of atmospheric emissions from a megacity. The Mexico City Metropolitan Area (MCMA) – one of the world's largest megacities and North America's most populous city – was selected as the case study to characterize the sources, concentrations, transport, and transformation processes of the gases and fine particles emitted to the MCMA atmosphere and to evaluate the regional and global impacts of these emissions. The findings of this study are relevant to the evolution and impacts of pollution from many other megacities.
The measurement phase consisted of a month-long series of carefully coordinated observations of the chemistry and physics of the atmosphere in and near Mexico City during March 2006, using a wide range of instruments at ground sites, on aircraft and satellites, and enlisting over 450 scientists from 150 institutions in 30 countries. Three ground supersites were set up to examine the evolution of the primary emitted gases and fine particles. Additional platforms in or near Mexico City included mobile vans containing scientific laboratories and mobile and stationary upward-looking lidars. Seven instrumented research aircraft provided information about the atmosphere over a large region and at various altitudes. Satellite-based instruments peered down into the atmosphere, providing even larger geographical coverage. The overall campaign was complemented by meteorological forecasting and numerical simulations, satellite observations and surface networks. Together, these research observations have provided the most comprehensive characterization of the MCMA's urban and regional atmospheric composition and chemistry that will take years to analyze and evaluate fully.
In this paper we review over 120 papers resulting from the MILAGRO/INTEX-B Campaign that have been published or submitted, as well as relevant papers from the earlier MCMA-2003 Campaign, with the aim of providing a road map for the scientific community interested in understanding the emissions from a megacity such as the MCMA and their impacts on air quality and climate.
This paper describes the measurements performed during MILAGRO and the results obtained on MCMA's atmospheric meteorology and dynamics, emissions of gases and fine particles, sources and concentrations of volatile organic compounds, urban and regional photochemistry, ambient particulate matter, aerosol radiative properties, urban plume characterization, and health studies. A summary of key findings from the field study is presented.Mexico. Comisión Ambiental MetropolitanaMexico. Ministry of the EnvironmentConsejo Nacional de Ciencia y Tecnología (Mexico)Petróleos MexicanosNational Science Foundation (U.S.). Atmospheric Chemistry ProgramAtmospheric Sciences Program (U.S.)United States. National Aeronautics and Space Administration. Radiation Science Progra
Treatment Outcomes of Patients With Multidrug-Resistant and Extensively Drug-Resistant Tuberculosis According to Drug Susceptibility Testing to First- and Second-line Drugs: An Individual Patient Data Meta-analysis
The clinical validity of drug susceptibility testing (DST) for pyrazinamide, ethambutol, and second-line antituberculosis drugs is uncertain. In an individual patient data meta-analysis of 8955 patients with confirmed multidrug-resistant tuberculosis, DST results for these drugs were associated with treatment outcome
Particulate air pollution, systemic oxidative stress, inflammation, and atherosclerosis
Air pollution has been associated with significant adverse health effects leading to increased overall morbidity and mortality of worldwide significance. Epidemiological studies have shown that the largest portion of air pollution-related mortality is due to cardiovascular diseases, predominantly those of ischemic nature. Human studies suggest an association with atherosclerosis and increasing experimental animal data support that this association is likely to be causal. While both gasses and particles have been linked to detrimental health effects, more evidence implicates the particulate matter (PM) components as major responsible for a large portion of the proatherogenic effects. Multiple experimental approaches have revealed the ability of PM components to trigger and/or enhance free radical reactions in cells and tissues, both ex vivo as well as in vivo. It appears that exposure to PM leads to the development of systemic prooxidant and proinflammatory effects that may be of great importance in the development of atherosclerotic lesions. This article reviews the epidemiological studies, experimental animal, and cellular data that support the association of air pollutants, especially the particulate components, with systemic oxidative stress, inflammation, and atherosclerosis. It also reviews the use of transcriptomic studies to elucidate molecular pathways of importance in those systemic effects
Ambient Particulate Matter Induces Interleukin-8 Expression through an Alternative NF-κB (Nuclear Factor-Kappa B) Mechanism in Human Airway Epithelial Cells
Background: Exposure to ambient air particulate matter (PM) has been shown to increase rates of cardiopulmonary morbidity and mortality, but the underlying mechanisms are still not well understood. Objective: We examined signaling events involved in the expression of the inflammatory gene interleukin-8 (IL-8) in human airway epithelial cells (HAECs) exposed to ambient PM collected in an urban area of Mexicali, Mexico. Methods: We studied IL-8 expression and regulatory signaling pathways in cultured HAECs exposed to Mexicali PM suspended in media for 0–4 hr. Results: Exposure resulted in a dose-dependent, 2- to 8-fold increase in IL-8 mRNA expression relative to controls. PM exposure induced IL-8 transcriptional activity in BEAS-2B cells that was dependent on the nuclear factor-kappa B (NF-κB) response element in the IL-8 promoter. Chromatin immunoprecipitation (ChIP) assays showed a 3-fold increase in binding of the p65 (RelA) NF-κB isoform to the IL-8 promoter sequence in HAECs exposed to PM. Western blot analyses showed elevated levels of phosphorylation of p65 but no changes in IκBα phosphorylation or degradation. IL-8 expression was blunted in a dose-dependent manner in BEAS-2B cells transduced with a lentivirus encoding a dominant negative p65 mutant in which phosphorylation sites were inactivated. Conclusion: Taken together, these findings show that the increase in IL-8 mRNA expression in HAECs exposed to PM(10) (PM ≤ 10 μm in aerodynamic diameter) is mediated through an NF-κB–dependent signaling mechanism that occurs through a pathway involving direct phosphorylation of the transcription factor p65 in the absence of IκBα degradation. These data show that exposure to PM(10) in ambient air can induce inflammatory responses by activating specific signaling mechanisms in HAECs