329 research outputs found

    HD 174005: another binary classified as lambda Boo

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    We demonstrate that HD 174005, a star recently classified as belonging to the lambda Boo group, is in reality a double lined spectroscopic binary; at some phases, the observed composite spectrum may be similar to that of a single star with weak metal lines.Comment: Accepted by A&

    Assessment of Deaths Attributable to Air Pollution: Should We Use Risk Estimates based on Time Series or on Cohort Studies?

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    Epidemiologic studies are crucial to the estimation of numbers of deaths attributable to air pollution. In this paper, the authors present a framework for distinguishing estimates of attributable cases based on time-series studies from those based on cohort studies, the latter being 5-10 times larger. The authors distinguish four categories of death associated with air pollution: A) air pollution increases both the risk of underlying diseases leading to frailty and the short term risk of death among the frail; B) air pollution increases the risk of chronic diseases leading to frailty but is unrelated to timing of death; C) air pollution is unrelated to risk of chronic diseases but short term exposure increases mortality among persons who are frail; and D) neither underlying chronic disease nor the event of death is related to air pollution exposure. Time-series approaches capture deaths from categories A and C, whereas cohort studies assess cases from categories A, B, and C. In addition, years of life lost can only be derived from cohort studies, where time to death is the outcome, while in time-series studies, death is a once-only event (no dimension in time). The authors conclude that time-series analyses underestimate cases of death attributable to air pollution and that assessment of the impact of air pollution on mortality should be based on cohort studie

    Simultane Behandlung von obliterativen Karotispathologien und koronarer Herzkrankheit: Aktuelles Konzept und Resultate der letzten 5Jahre

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    Zusammenfassung: Einführung: Die kombinierte Karotisendarteriektomie und aorto-coronare Baypassoperation (C-CABG) weisen ein hohes peri-operatives Risiko auf. Als Alternative wird in letzter Zeit das Stenting der Artera carotis interna propagiert. Das Fehlen von Level I Evidenz hat uns motiviert, die Resultate unserer C-CABG der letzten 5 Jahre zu evaluieren. Methoden und Patienten: Retrospektive Monozenterstudie von 113C-CABG, durchgeführt zwischen Januar 2000 und Dezember 2004. Das mediane Alter der Patienten betrug 65Jahre (22Patienten waren 80Jahre alt oder älter). Die Karotisendarteriektomie wurde vor der aortokoronaren Bypassoperation in derselben Narkose durchgeführt. Resultate: Die 30-Tages-Mortalität war ausschließlich kardial bedingt und betrug 4,4% (5/113). Die neurologischen Komplikationen waren ein Schlaganfall, der innerhalb von 30Tagen vollständig regredient war, und 3TIA (3,5%, 4/113). Schlussfolgerung: C-CABG mit initial durchgeführter Karotisendarteriektomie ist ein sicheres Verfahren mit niedriger neurologischer Komplikationsrate. Der riskante Anteil des kombinierten Eingriffs ist nicht die Karotisendarteriektomie, sondern die aortokoronare Revaskularisation. Demzufolge scheint das Stenting beim kombinierten Eingriff als Alternative nicht gerechtfertigt, solange keine klaren Vorteile hinsichtlich der Früh- und Langzeitresultate gegenüber der alleinigen Karotisendarteriektomie vorliege

    Development and Evaluation of a Smartphone-Based Chatbot Coach to Facilitate a Balanced Lifestyle in Individuals With Headaches (BalanceUP App): Randomized Controlled Trial

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    Background Primary headaches, including migraine and tension-type headaches, are widespread and have a social, physical, mental, and economic impact. Among the key components of treatment are behavior interventions such as lifestyle modification. Scalable conversational agents (CAs) have the potential to deliver behavior interventions at a low threshold. To our knowledge, there is no evidence of behavioral interventions delivered by CAs for the treatment of headaches. Objective This study has 2 aims. The first aim was to develop and test a smartphone-based coaching intervention (BalanceUP) for people experiencing frequent headaches, delivered by a CA and designed to improve mental well-being using various behavior change techniques. The second aim was to evaluate the effectiveness of BalanceUP by comparing the intervention and waitlist control groups and assess the engagement and acceptance of participants using BalanceUP. Methods In an unblinded randomized controlled trial, adults with frequent headaches were recruited on the web and in collaboration with experts and allocated to either a CA intervention (BalanceUP) or a control condition. The effects of the treatment on changes in the primary outcome of the study, that is, mental well-being (as measured by the Patient Health Questionnaire Anxiety and Depression Scale), and secondary outcomes (eg, psychosomatic symptoms, stress, headache-related self-efficacy, intention to change behavior, presenteeism and absenteeism, and pain coping) were analyzed using linear mixed models and Cohen d. Primary and secondary outcomes were self-assessed before and after the intervention, and acceptance was assessed after the intervention. Engagement was measured during the intervention using self-reports and usage data. Results A total of 198 participants (mean age 38.7, SD 12.14 y; n=172, 86.9% women) participated in the study (intervention group: n=110; waitlist control group: n=88). After the intervention, the intention-to-treat analysis revealed evidence for improved well-being (treatment: β estimate=–3.28, 95% CI –5.07 to –1.48) with moderate between-group effects (Cohen d=–0.66, 95% CI –0.99 to –0.33) in favor of the intervention group. We also found evidence of reduced somatic symptoms, perceived stress, and absenteeism and presenteeism, as well as improved headache management self-efficacy, application of behavior change techniques, and pain coping skills, with effects ranging from medium to large (Cohen d=0.43-1.05). Overall, 64.8% (118/182) of the participants used coaching as intended by engaging throughout the coaching and completing the outro. Conclusions BalanceUP was well accepted, and the results suggest that coaching delivered by a CA can be effective in reducing the burden of people who experience headaches by improving their well-being. Trial Registration German Clinical Trials Register DRKS00017422; https://trialsearch.who.int/Trial2.aspx?TrialID=DRKS0001742

    The role of burden of disease assessment in tracking progress towards achieving WHO global air quality guidelines

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    OBJECTIVES: More than 90% of the global population live in areas exceeding the PM2.5 air quality guidelines (AQGs). We provide an overview of the ambient PM2.5-related burden of disease (BoD) studies along with scenario analysis in the framework of the WHO AQG update on the estimated reduction in the BoD if AQGs were achieved globally. METHODS: We reviewed the literature for large-scale studies for the BoD attributed to ambient PM2.5. Moreover, we used the latest WHO statistics to calculate the BoD at current levels and the scenarios of aligning with interim targets and AQG levels. RESULTS: The most recent BoD studies (2010 onwards) share a similar methodology, but there are differences in the input data which affect the estimates for attributable deaths (2.9-8.9 million deaths annually). Moreover, we found that if AQGs were achieved, the estimated BoD would be reduced by up to 50% in total deaths worldwide. CONCLUSIONS: Understanding the BoD across countries, especially in those that do not align with the AQGs, is essential in order to inform actions to reduce air pollution globally

    Predictors of complications in acute type B aortic dissection

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    Objectives: Medical treatment is generally advocated for patients with acute type B aortic dissection without complications. The objective of this retrospective analysis was to determine whether there are any initial findings that can help predict the long-term course of the disease. Methods: Case records of the 130 patients treated for type B aortic dissection between 1988 and 1997 were reviewed; 41 (31%) were operated on in the acute phase (≪14 days), 31 (24%) were operated on in the chronic phase and 58 (45%) were treated medically. Results: Overall acute mortality was 10.8%; 22% for patients operated on in the early phase and 5.6% for medically treated patients. Age (P=0.002), persistent pain (P=0.01) and malperfusion (P=0.001) were significant independent predictors of the need for surgery. Paraplegia/para paresis (P=0.0001), leg ischaemia (P=0.003), pleural effusion (P=0.003), rupture (P=0.0001), shock (P=0.0001), age (P=0.003), cardiac failure (P=0.002) and aortic diameter ≫4.5cm (P=0.002) were significant predictors of poor survival. Age and shock also emerged as independent risk factors. Patients without malperfusion (P=0.0001), pleural effusion (P=0.003), rupture (P=0.0001) and shock (P=0.0001) had a significantly better event-free survival (freedom from repeat surgery and death). The actuarial survival rate for high-risk patients (malperfusion, rupture, shock) was 62% at 1 year and 40% at 5 years; the corresponding values for low-risk patients were 94 and 84%, respectively. Conclusions: Rupture, shock and malperfusion are significant predictors of poor survival in patients with acute type B aortic dissectio

    Mortality attributable to ambient fine particulate matter and nitrogen dioxide in Switzerland in 2019: use of two-pollutant effect estimates

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    INTRODUCTION: Air pollution health risk assessments have traditionally used single-pollutant effect estimates for one proxy ambient air pollutant such as PM(2.5). Two-pollutant effect estimates, i.e. adjusted for another correlated pollutant, theoretically enable the aggregation of pollutant-specific health effects minimizing double-counting. Our study aimed at estimating the adult mortality in Switzerland in 2019 attributable to PM(2.5) from a single-pollutant effect estimate and to the sum of PM(2.5) and NO(2) from two-pollutant estimates; comparing the results with those from alternative global, European and Swiss effect estimates. METHODS: For the single-pollutant approach, we used a PM(2.5) summary estimate of European cohorts from the project ELAPSE, recommended by the European Respiratory Society and International Society for Environmental Epidemiology (ERS-ISEE). To derive the two-pollutant effect estimates, we applied ELAPSE-based conversion factors to ERS-ISEE PM(2.5) and NO(2) single-pollutant effect estimates. Additionally, we used World Health Organization 2021 Air Quality Guidelines as counterfactual scenario, exposure model data from 2019 and Swiss lifetables. RESULTS: The single-pollutant effect estimate for PM(2.5) (1.118 [1.060; 1.179] per 10 mug/m(3)) resulted in 2240 deaths (21,593 years of life lost). Using our derived two-pollutant effect estimates (1.023 [1.012; 1.035] per 10 mug/m(3) PM(2.5) adjusted for NO(2) and 1.040 [1.023; 1.058] per 10 mug/m(3) NO(2) adjusted for PM(2.5)), we found 1977 deaths (19,071 years of life lost) attributable to PM(2.5) and NO(2) together (23% from PM(2.5)). Deaths using alternative effect estimates ranged from 1042 to 5059. DISCUSSION: Estimated premature mortality attributable to PM(2.5) alone was higher than to both PM(2.5) and NO(2) combined. Furthermore, the proportion of deaths from PM(2.5) was lower than from NO(2) in the two-pollutant approach. These seemingly paradoxical results, also found in some alternative estimates, are due to statistical imprecisions of underlying correction methods. Therefore, using two-pollutant effect estimates can lead to interpretation challenges in terms of causality

    Methods matter: a comparative review of health risk assessments for ambient air pollution in Switzerland

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    Objectives: Air pollution health risk assessments (AP-HRAs) provide a method to quantify health effects for entire populations. In Switzerland, AP-HRAs are included in Swiss assessments for Transport Externalities (STEs), ordered by public authorities since the 1990s. This study aimed to describe the differences among national and international AP-HRAs for Switzerland. Methods: We compared input data, approaches and results across AP-HRAs over time. Results and input data for each AP-HRA were expressed as a ratio compared to the most recent STE (in most cases STE-2010). Results: Substantial variation across AP-HRAs was found. For all-cause adult mortality attributed to particulate matter (the most frequent outcome-pollutant pair), the ratio in HRAs oscillated from 0.40 to 2.09 (times the STE-2010 value). Regarding input data, the ratio ranged from 0.69 to 1.26 for population exposure, from 0 to 1.81 for counterfactual scenario, from 0.96 to 1.13 for concentration-response function and from 1.03 to 1.13 for baseline health data. Conclusion: This study demonstrates that methods matter for AP-HRAs. Transparent and possibly standardized reporting of key input data and assumptions should be promoted to facilitate comparison of AP-HRAs

    Explanted cryopreserved allografts: a morphological and immunohistochemical comparison between arterial allografts and allograft heart valves from infants and adults

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    Objective: Life expectancy of cryopreserved allografts implanted in infants is different from those implanted in adults. A morphological study of explanted allograft heart valves was performed to determine the mechanism of deterioration and to compare cryopreserved arterial and heart valve allografts from adult patients with those explanted from infants. Method: Between 1987 and 1996, 209 cryopreserved allografts were implanted: 125 valved conduits or monocusps to reconstruct the right ventricular outflow tract in congenital heart disease, 50 allograft heart valves to treat native aortic and prosthetic aortic valve endocarditis and 34 cryopreserved arterial allografts to replace mycotic aortic aneurysms or infected aortic prosthetic grafts. Two months to 8 years after implantation, 23 heart valve allografts, 11 right-sided and 12 left-sided, and four arterial allografts had to be explanted for reasons such as degeneration, recurrent infection, aneurysm formation or rupture. Besides conventional staining, immunohistochemical detection of cell populations was performed as follows: CD45RO, CD3 and CD43 for T lymphocytes, CD20 for B lymphocytes, CD68 for macrophages, protein S100 for Langerhans-cells, vimentin for fibroblasts, α-actin for smooth muscle cells and factor VIII for endothelial cells. Results: Explanted cryopreserved allografts were all fibrotic, acellular, non-vital and without endothelial cells. The fibrous tissue was preserved. T lymphocytes, indicating rejection, were found in all right-sided allografts from the paediatric population, but only in 9% of left-sided valves explanted from adults and in one of the four of arterial allografts. Macrophages and Langerhans-cells were found only in right-sided allografts from paediatric patients. Conclusion: Right-sided cryopreserved allografts from a paediatric population showed ongoing cellular rejection. By contrast, there was only a weak T-cell mediated rejection to adult heart valve and arterial allografts. Therefore, similar long-term results can be expected in adult arterial and heart valve allografts, whereas longevity of right-sided heart valve allograft in the paediatric age group seems endangered by cellular rejectio
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