| 1. |
- Schaap, M., et al.
(författare)
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Standardized evaluation methodology and reference database for evaluating coronary artery centerline extraction algorithms
- 2009
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Ingår i: Medical Image Analysis. - : Elsevier. - 1361-8415 .- 1361-8423. ; 13:5, s. 701-714
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Tidskriftsartikel (refereegranskat)abstract
- Efficiently obtaining a reliable coronary artery centerline from computed tomography angiography data is relevant in clinical practice. Whereas numerous methods have been presented for this purpose, up to now no standardized evaluation methodology has been published to reliably evaluate and compare the performance of the existing or newly developed coronary artery centerline extraction algorithms. This paper describes a standardized evaluation methodology and reference database for the quantitative evaluation of coronary artery centerline extraction algorithms. The contribution of this work is fourfold: (1) a method is described to create a consensus centerline with multiple observers, (2) well-defined measures are presented for the evaluation of coronary artery centerline extraction algorithms, (3) a database containing 32 cardiac CTA datasets with corresponding reference standard is described and made available, and (4) 13 coronary artery centerline extraction algorithms, implemented by different research groups, are quantitatively evaluated and compared. The presented evaluation framework is made available to the medical imaging community for benchmarking existing or newly developed coronary centerline extraction algorithms.
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| 2. |
- Dorfmeister, B, et al.
(författare)
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Effects of six APOA5 variants, identified in patients with severe hypertriglyceridemia, on in vitro lipoprotein lipase activity and receptor binding
- 2008
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Ingår i: Arteriosclerosis, Thrombosis and Vascular Biology. - 1079-5642 .- 1524-4636. ; 28:10, s. 1866-1871
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Tidskriftsartikel (refereegranskat)abstract
- OBJECTIVE: The purpose of this study was to identify rare APOA5 variants in 130 severe hypertriglyceridemic patients by sequencing, and to test their functionality, since no patient recall was possible. METHODS AND RESULTS: We studied the impact in vitro on LPL activity and receptor binding of 3 novel heterozygous variants, apoAV-E255G, -G271C, and -H321L, together with the previously reported -G185C, -Q139X, -Q148X, and a novel construct -Delta139 to 147. Using VLDL as a TG-source, compared to wild type, apoAV-G255, -L321 and -C185 showed reduced LPL activation (-25% [P=0.005], -36% [P<0.0001], and -23% [P=0.02]), respectively). ApoAV-C271, -X139, -X148, and Delta139 to 147 had little affect on LPL activity, but apoAV-X139, -X148, and -C271 showed no binding to LDL-family receptors, LR8 or LRP1. Although the G271C proband carried no LPL and APOC2 mutations, the H321L carrier was heterozygous for LPL P207L. The E255G carrier was homozygous for LPL W86G, yet only experienced severe hypertriglyceridemia when pregnant. CONCLUSIONS: The in vitro determined function of these apoAV variants only partly explains the high TG levels seen in carriers. Their occurrence in the homozygous state, coinheritance of LPL variants or common APOA5 TG-raising variant in trans, appears to be essential for their phenotypic expression.
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| 3. |
- Abrahamyan, Lilit, et al.
(författare)
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A Problem Solving Environment for Image-Based Computational Hemodynamics
- 2005
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Konferensbidrag (refereegranskat)abstract
- We introduce a complete problem solving environment designed for pulsatile flows in 3D complex geometries, especially arteries. Three-dimensional images from arteries, obtained from e.g. Magnetic Resonance Imaging, are segmented to obtain a geometrical description of the arteries of interest. This segmented artery is prepared for blood flow simulations in a 3D editing tool, allowing to define in- and outlets, to filter and crop part of the artery, to add certain structures ( e.g. a by-pass, or stents ), and to generate computational meshes as input to the blood flow simulators. Using dedicated fluid flow solvers the time dependent blood flow in the artery during one systole is computed. The resulting flow, pressure and shear stress fields are then analyzed using a number of visualization techniques. The whole environment can be operated from a desktop virtual reality system, and is embedded in a Grid computing environment.
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| 4. |
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| 5. |
- Schaap, M. M., et al.
(författare)
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Effect of nationwide tobacco control policies on smoking cessation in high and low educated groups in 18 European countries
- 2008
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Ingår i: Tobacco Control. - : BMJ. - 0964-4563 .- 1468-3318. ; 17:4, s. 248-255
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Tidskriftsartikel (refereegranskat)abstract
- Background: Recently a scale was introduced to quantify the implementation of tobacco control policies at country level. Our study used this scale to examine the potential impact of these policies on quit ratios in European countries. Special attention was given to smoking cessation among lower educational groups. Methods: Cross-sectional data were derived from national health surveys from 18 European countries. In the analyses we distinguished between country, sex, two age groups (25-39 and 40-59 years) and educational level. Age-standardised quit ratios were calculated as total former-smokers divided by total ever-smokers. In regression analyses we explored the correlation between national quit ratios and the national score on the Tobacco Control Scale (TCS). Results: Quit ratios were especially high (> 45%) in Sweden, England, The Netherlands, Belgium and France and relatively low (< 30%) in Lithuania and Latvia. Higher educated smokers were more likely to have quit smoking than lower educated smokers in all age-sex groups in all countries. National score on the tobacco control scale was positively associated with quit ratios in all age-sex groups. The association of quit ratios with score on TCS did not show consistent differences between high and low education. Of all tobacco control policies of which the TCS is constructed, price policies showed the strongest association with quit ratios, followed by an advertising ban. Conclusion: Countries with more developed tobacco control policies have higher quit ratios than countries with less developed tobacco control policies. High and low educated smokers benefit about equally from the nationwide tobacco control policies.
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| 6. |
- Vautard, R., et al.
(författare)
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Skill and uncertainty of a regional air quality model ensemble
- 2009
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Ingår i: Atmospheric Environment. - : Elsevier BV. - 1352-2310. ; 43:31, s. 4822-4832
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Tidskriftsartikel (refereegranskat)abstract
- Recently several regional air quality projects were carried out to support the negotiation under the Clean Air For Europe (CAFE) programme by predicting the impact of emission control policies with an ensemble of models. Within these projects, CITYDELTA and EURODELTA, the fate of air quality at the scale of European cities or that of the European continent was studied using several models. In this article we focus on the results of EURODELTA. The predictive skill of the ensemble of models is described for ozone, nitrogen dioxide and secondary inorganic compounds, and the uncertainty in air quality modelling is examined through the model ensemble spread of concentrations. For ozone daily maxima the ensemble spread origin differs from one region to another. In the neighbourhood of cities or in mountainous areas the spread of predicted values does not span the range of observed data, due to poorly resolved emissions or complex-terrain meteorology. By contrast in Atlantic and North Sea coastal areas the spread of predicted values is found to be larger than the observations. This is attributed to large differences in the boundary conditions used in the different models. For NO2 daily averages the ensemble spread is generally too small compared with observations. This is because models miss highest values occurring in stagnant meteorology in stable boundary layers near cities. For secondary particulate matter compounds the simulated concentration spread is more balanced, observations falling nearly equiprobably within the ensemble, and the spread originates both from meteorology and aerosol chemistry and thermodynamics. © 2008.
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| 7. |
- Mackenbach, Johan P, et al.
(författare)
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Socioeconomic inequalities in health in 22 European countries
- 2008
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Ingår i: New England Journal of Medicine. - 0028-4793 .- 1533-4406. ; 358:23, s. 2468-2481
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Tidskriftsartikel (refereegranskat)abstract
- We observed variation across Europe in the magnitude of inequalities in health associated with socioeconomic status. These inequalities might be reduced by improving educational opportunities, income distribution, health-related behavior, or access to health care.
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| 8. |
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| 9. |
- Schaap, Maartje M, et al.
(författare)
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Female ever-smoking, education, emancipation and economic development in 19 European countries
- 2009
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Ingår i: Social Science and Medicine. - : Elsevier BV. - 0277-9536 .- 1873-5347. ; 68:7, s. 1271-1278
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Tidskriftsartikel (refereegranskat)abstract
- Large differences in ever-smoking rates among women are found between countries and socio-economic groups. This study examined the socio-economic inequalities in female ever-smoking rates in 19 European countries, and explored the association between cross-national differences in these inequalities and economic development and women's emancipation. Data on smoking were derived from national health interview surveys from 19 European countries. For each country, age group (25-39, 40-59 and 60+ years), educational level (4 standard levels), and cumulative ever-smoking rates were calculated as the proportion of current and former smokers of the total survey population. A Relative Index of Inequality was estimated for women in the three age groups to measure the magnitude of educational differences. In regression analyses the association of ever-smoking rates of women age 25-39 years with the gross domestic product (GDP) and the Gender Empowerment Measure (GEM) was explored. Less educated women aged 25-39 years were more likely to have ever smoked than more educated women in all countries, except Portugal. In the age groups 40-59 years the educational pattern differed between countries. Women aged 60+ years who were less educated were less likely to have ever smoked in all countries, except Norway and England. The size of inequalities varied considerably between countries and reversed within three age groups. For women 25-39 years, the association of ever-smoking rates with GDP was positive, especially for more educated women. The association of ever-smoking rates with GEM was positive for less educated women, but negative for more educated women. The results are consistent with the idea that economic development and social-cultural processes related to gender empowerment have affected the diffusion of smoking in different ways for more and less educated women.
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| 10. |
- Van der Heyden, J H A, et al.
(författare)
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Socioeconomic inequalities in lung cancer mortality in 16 European populations.
- 2009
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Ingår i: Lung Cancer. - : Elsevier BV. - 0169-5002 .- 1872-8332. ; 63:3, s. 322-330
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Tidskriftsartikel (refereegranskat)abstract
- Important socioeconomic inequalities exist in lung cancer mortality in Europe. They are consistent with the geographical spread of the smoking epidemic. In the next decades socioeconomic inequalities in lung cancer mortality are likely to persist and even increase among women. In Southern European countries we may expect a reversal from a positive to a negative association between socioeconomic status and lung cancer mortality. Continuous efforts are necessary to tackle socioeconomic inequalities in lung cancer mortality in all European countries.
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