404 research outputs found

    Leukemia, Brain Tumors, and Exposure to Extremely Low Frequency Electromagnetic Fields in Swiss Railway Employees

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    Railway engineers provide excellent opportunities for studying the relation between exposure to extremely low frequency magnetic fields and leukemia or brain tumors. In a cohort study of Swiss railway personnel with 2.7 × 105 person-years of follow-up (1972-1993), the authors compared occupations with high average exposures (line engineers: 25.9 μT) to those with medium and low exposures (station masters: 1 μT). The mortality rate ratio for leukemia was 2.4 (95% confidence interval (CI): 1.0, 6.1) among line engineers (reference category: station masters). The mortality rate ratio for brain tumors was 1.0 (95% CI: 0.2, 4.6) among line engineers and 5.1 (95% CI: 1.2, 21.2) among shunting yard engineers (compared with station masters). Two exposure characteristics were evaluated: cumulative exposure in μT-years and years spent under exposure to magnetic fields of ≥10 μT. There was a significant increase in leukemia mortality of 0.9% (95% CI: 0.2, 1.7) per μT-year of cumulative exposure to extremely low frequency magnetic fields. The increase by years spent under exposure of ≥10 μT was even stronger: 62% per year (95% CI: 15, 129). Brain cancer risk did not show a dose-response relation. This study contributes to the evidence for a link between heavy exposure to extremely low frequency magnetic fields and leukemia. Its strengths include reliable measurements and reliable historical reconstruction of exposure

    Crystal structure of the human ATP-dependent splicing and export factor UAP56

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    Pre-mRNA splicing requires the function of a number of RNA-dependent ATPases/helicases, yet no three-dimensional structure of any spliceosomal ATPases/helicases is known. The highly conserved DECD-box protein UAP56/Sub2 is an essential splicing factor that is also important for mRNA export. The expected ATPase/helicase activity appears to be essential for the UAP56/Sub2 functions. Here, we show that purified human UAP56 is an active RNA-dependent ATPase, and we also report the crystal structures of UAP56 alone and in complex with ADP, as well as a DECD to DEAD mutant. The structures reveal a unique spatial arrangement of the two conserved helicase domains, and ADP-binding induces significant conformational changes of key residues in the ATP-binding pocket. Our structural analyses suggest a specific protein-RNA displacement model of UAP56/Sub2. The detailed structural information provides important mechanistic insights into the splicing function of UAP56/Sub2. The structures also will be useful for the analysis of other spliceosomal DExD-box ATPases/helicases

    Superconductivity enhanced conductance fluctuations in few layer graphene nanoribbons

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    We investigate the mesoscopic disorder induced rms conductance variance δG\delta G in a few layer graphene nanoribbon (FGNR) contacted by two superconducting (S) Ti/Al contacts. By sweeping the back-gate voltage, we observe pronounced conductance fluctuations superimposed on a linear background of the two terminal conductance G. The linear gate-voltage induced response can be modeled by a set of inter-layer and intra-layer capacitances. δG\delta G depends on temperature T and source-drain voltage VsdV_{sd}. δG\delta G increases with decreasing T and Vsd|V_{sd}|. When lowering Vsd|V_{sd}|, a pronounced cross-over at a voltage corresponding to the superconducting energy gap Δ\Delta is observed. For |V_{sd}|\ltequiv \Delta the fluctuations are markedly enhanced. Expressed in the conductance variance GGSG_{GS} of one graphene-superconducutor (G-S) interface, values of 0.58 e^2/h are obtained at the base temperature of 230 mK. The conductance variance in the sub-gap region are larger by up to a factor of 1.4-1.8 compared to the normal state. The observed strong enhancement is due to phase coherent charge transfer caused by Andreev reflection at the nanoribbon-superconductor interface.Comment: 15 pages, 5 figure

    Adverse Event Assessment of Antimuscarinics for Treating Overactive Bladder: A Network Meta-Analytic Approach

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    BACKGROUND: Overactive bladder (OAB) affects the lives of millions of people worldwide and antimuscarinics are the pharmacological treatment of choice. Meta-analyses of all currently used antimuscarinics for treating OAB found similar efficacy, making the choice dependent on their adverse event profiles. However, conventional meta-analyses often fail to quantify and compare adverse events across different drugs, dosages, formulations, and routes of administration. In addition, the assessment of the broad variety of adverse events is dissatisfying. Our aim was to compare adverse events of antimuscarinics using a network meta-analytic approach that overcomes shortcomings of conventional analyses. METHODS: Cochrane Incontinence Group Specialized Trials Register, previous systematic reviews, conference abstracts, book chapters, and reference lists of relevant articles were searched. Eligible studies included randomized controlled trials comparing at least one antimuscarinic for treating OAB with placebo or with another antimuscarinic, and adverse events as outcome measures. Two authors independently extracted data. A network meta-analytic approach was applied allowing for joint assessment of all adverse events of all currently used antimuscarinics while fully maintaining randomization. RESULTS: 69 trials enrolling 26'229 patients were included. Similar overall adverse event profiles were found for darifenacin, fesoterodine, transdermal oxybutynin, propiverine, solifenacin, tolterodine, and trospium chloride but not for oxybutynin orally administered when currently used starting dosages were compared. CONCLUSIONS: The proposed generally applicable transparent network meta-analytic approach summarizes adverse events in an easy to grasp way allowing straightforward benchmarking of antimuscarinics for treating OAB in clinical practice. Most currently used antimuscarinics seem to be equivalent first choice drugs to start the treatment of OAB except for oral oxybutynin dosages of ≥ 10 mg/d which may have more unfavorable adverse event profiles

    Association of diabetes with atrial fibrillation types: a systematic review and meta-analysis

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    Background: Atrial fibrillation (AF) is a common arrhythmia classified as paroxysmal and non-paroxysmal. Non-paroxysmal AF is associated with an increased risk of complications. Diabetes contributes to AF initiation, yet its role in AF maintenance is unclear. We conducted a systematic review and meta-analysis to summarize the evidence regarding the association of diabetes with AF types. Methods: We searched 5 databases for observational studies investigating the association of diabetes with the likelihood of an AF type (vs another type) in humans. Study quality was evaluated using the Newcastle-Ottawa Scale. Studies classifying AF types as paroxysmal (reference) and non-paroxysmal were pooled in a meta-analysis using random effects models. Results: Of 1997 articles we identified, 20 were included in our systematic review. The population sample size ranged from 64 to 9816 participants with mean age ranging from 40 to 75 years and percentage of women from 24.8 to 100%. The quality of studies varied from poor (60%) to fair (5%) to good (35%). In the systematic review, 8 studies among patients with AF investigated the cross-sectional association of diabetes with non-paroxysmal AF (vs paroxysmal) of which 6 showed a positive association and 2 showed no association. Fourteen studies investigated the longitudinal association of diabetes with "more sustained" AF types (vs "less sustained") of which 2 showed a positive association and 12 showed no association. In the meta-analysis of cross-sectional studies, patients with AF and diabetes were 1.31-times more likely to have non-paroxysmal AF than those without diabetes [8 studies; pooled OR (95% CI), 1.31 (1.13-1.51), I2 = 82.6%]. The meta-analysis of longitudinal studies showed that for patients with paroxysmal AF, diabetes is associated with 1.32-times increased likelihood of progression to non-paroxysmal AF [five studies; pooled OR (95% CI), 1.32 (1.07-1.62); I2 = 0%]. Conclusions: Our findings suggest that diabetes is associated with an increased likelihood of non-paroxysmal AF rather than paroxysmal AF. However, further high quality studies are needed to replicate these findings, adjust for potential confounders, elucidate mechanisms linking diabetes to non-paroxysmal AF, and assess the impact of antidiabetic medications on AF types. These strategies could eventually help decrease the risk of non-paroxysmal AF among patients with diabetes

    Systematic Review of Physical Activity Trajectories and Mortality in Patients With Coronary Artery Disease.

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    BACKGROUND The role of lifestyle physical activity (PA) trajectories in the mortality risk of patients with coronary heart disease (CHD) remains unclear. OBJECTIVES The purpose of this study was to determine the association of longitudinal PA trajectories with all-cause and cardiovascular disease (CVD) mortality in patients with CHD. METHODS Longitudinal cohorts reporting the association of PA trajectories with mortality in patients with CHD were identified in April 2021 by searching 5 databases without language restrictions. Published HRs and 95% CIs were pooled using random effects models and bias assessed by Egger regression. RESULTS A total of 9 prospective cohorts included 33,576 patients. The mean age was 62.5 years. The maximum follow-up was 15.7 years. All of the studies assessed PA through validated questionnaires, and mortality was well documented. Changes in PA defined 4 nominal PA trajectories. Compared with always-inactive patients, the risk of all-cause mortality was 50% lower in those who remained active (HR: 0.50; 95% CI: 0.39-0.63); 45% lower in those who were inactive but became active (HR: 0.55; 95% CI: 0.44-0.7); and 20% lower in those who were active but became inactive (HR: 0.80; 95% CI: 0.64-0.99). Similar results were observed for CVD mortality, except for the category of decreased activity (HR: 0.91; 95% CI: 0.67-1.24). The overall risk of bias was low. No evidence of publication bias was found. Multiple sensitivity analyses provided consistent results. CONCLUSIONS This study illustrates how patients with CHD may benefit by preserving or adopting an active lifestyle. The observation that the benefits of past activity can be weakened or lost if PA is not maintained may be confounded by disease progression

    Urban Governance, Multisectoral Action, and Civic Engagement for Population Health, Wellbeing, and Equity in Urban Settings: A Systematic Review.

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    Objectives: To identify the validated and reliable indicators and tools to assess good governance for population health, wellbeing, and equity in urban settings, and assess processes of multisectoral action and civic engagement as reported by peer-reviewed articles. Methods: We conducted a systematic review searching six databases for observational studies reporting strategies of either urban health, multisectoral action or civic engagement for wellbeing, health, or equity. Results: Out of 8,154 studies initially identified we included 17. From the included studies, 14 presented information about high-income countries. The general population was the main target in most studies. Multisectoral action was the most frequently reported strategy (14 studies). Three studies used Urban Health Equity Assessment and Response Tool (Urban HEART). Health indicators were the most frequently represented (6 studies). Barriers and facilitators for the implementation of participatory health governance strategies were reported in 12 studies. Conclusion: Data on the implementation of participatory health governance strategies has been mainly reported in high-income countries. Updated and reliable data, measured repeatedly, is needed to closely monitor these processes and further develop indicators to assess their impact on population health, wellbeing, and equity

    Geomorphology variables predict fish assemblages for forested and endorheic rivers of two continents

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    Stream fishes are restricted to specific environments with appropriate habitats for feeding and reproduction. Interactions between streams and surrounding landscapes influence the availability and type of fish habitat, nutrient concentrations, suspended solids, and substrate composition. Valley width and gradient are geomorphological variables that influence the frequency and intensity that a stream interacts with the surrounding landscape. For example, in constrained valleys, canyon walls are steeply sloped and valleys are narrow, limiting the movement of water into riparian zones. Wide valleys have long, flat floodplains that are inundated with high discharge. We tested for differences in fish assemblages with geomorphology variation among stream sites. We selected rivers in similar forested and endorheic ecoregion types of the United States and Mongolia. Sites where we collected were defined as geomorphologically unique river segments (i.e., functional process zones; FPZs) using an automated ArcGIS-based tool. This tool extracts geomorphic variables at the valley and catchment scales and uses them to cluster stream segments based on their similarity. We collected a representative fish sample from replicates of FPZs. Then, we used constrained ordinations to determine whether river geomorphology could predict fish assemblage variation. Our constrained ordination approach using geomorphology to predict fish assemblages resulted in significance using fish taxonomy and traits in several watersheds. The watersheds where constrained ordinations were not successful were next analyzed with unconstrained ordinations to examine patterns among fish taxonomy and traits with geomorphology variables. Common geomorphology variables as predictors for taxonomic fish assemblages were river gradient, valley width, and valley slope. Significant geomorphology predictors of functional traits were valley width-to-floor width ratio, elevation, gradient, and channel sinuosity. These results provide evidence that fish assemblages respond similarly and strongly to geomorphic variables on two continents
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