Voronoi-based geometry estimator for 3D digital surfaces

14 pagesWe propose a robust estimator of geometric quantities such as normals, curvature directions and sharp features for 3D digital surfaces. This estimator only depends on the digitisation gridstep and is defined using a digital version of the Voronoi Covariance Measure, which exploits the robust geometric information contained in the Voronoi cells. It has been proved that the Voronoi Covariance Measure is resilient to Hausdorff noise. Our main theorem explicits the conditions under which this estimator is multigrid convergent for digital data. Moreover, we determine what are the parameters which maximise the convergence speed of this estimator, when the normal vector is sought. Numerical experiments show that the digital VCM estimator reliably estimates normals, curvature directions and sharp features of 3D noisy digital shapes

Weak coupling strategy between FE and SPH methods for FSI simulations

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SPH-FEM coupling to simulate Fluid-Structure Interactions with complex free-surface flows

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An efficient FSI coupling strategy between Smoothed Particle Hydrodynamics and Finite Element methods

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P626Higher fitness is associated with improved survival among cancer patients

Abstract Background Cardio-respiratory fitness (CRF) is a known predictor of cardiovascular morbidity and mortality. However, data on the association of CRF with survival following a diagnosis of cancer is limited. Purpose To evaluate the association between CRF in a large cohort of asymptomatic adults and a probability of survival after subsequent cancer diagnosis. Methods We evaluated asymptomatic self-referred adults aged 40–79 years who were screened annually at a tertiary medical center. All subjects were free of cardiovascular disease and cancer at baseline and completed maximal exercise stress test according to the Bruce protocol. Fitness was categorized into age- and sex-specific quintiles (Q) according to Bruce protocol treadmill time with Q1-Q2 defined as low fitness and Q3-Q5 as higher fitness. Cancer data was available from a national cancer registry. The primary end point was all-cause mortality. Results Final study population in included 15,800 subjects. Mean age was 51±8 years and 72% were men. During median follow up of 13 years (IQR 7–16) 1,312 (8%) subjects developed cancer and 486 (3%) died. Most common cancer types were prostate in 302 (23%) and breast cancer in 189 (14%) patients. No difference was found in distribution of major cancer types between different fitness categories. Univariate Cox regression with cancer as a time dependent covariate showed that subjects who developed cancer during follow up were 19 times more likely to die (95% CI 15.5–22.5, p&lt;0.001). Kaplan Meier analysis showed that the cumulative probability of death from the time of cancer diagnosis was significantly lower among high fitness patients (34% ± 4% vs. 25% ± 3%, p Log rank = 0.008; Figure 1). Multivariate interaction analysis with cancer as a time dependent covariate showed that cancer-related risk of death was fitness-dependent, such that in the lower fitness group cancer was associated with 18 folds increased risk of death (95% CI: 13.5–23) whereas among high fitness group the risk of death was lower (HR=13; 95% CI: 10–17; p for interaction = 0.048). Conclusions Low CRF is associated with worse survival among subjects diagnosed as having cancer during follow up. These findings support the effectiveness of fitness assessment in preventive health care settings. </jats:sec

Incident cardiovascular events and risk of subsequent cancer diagnosis

Abstract Background Cardiovascular disease (CVD) and cancer share common risk factors. This study investigated the association of CVD diagnosis and the risk of future cancer. Methods We evaluated asymptomatic self-referred adults aged 40–79 years who participated in a screening program. All subjects were free of CVD and cancer at baseline. CVD was defined as the composite of acute coronary syndrome, percutaneous coronary intervention or stroke. Cancer and mortality data were available for all subjects from national registries. Primary end-point was development of cancer during follow up. Cox regression models were applied with CVD as a time-dependent covariate and death as a competing risk event. Results Final study population included 15,486 subjects. Median age was 50 years (Interquartile range [IQR] 44–55) and 72% were men. During median follow up time of 11 years (IQR 6–15) 1,028 (7%) subjects developed CVD, 1,281 (8%) developed cancer and 499 (3%) died. Most common cancer types were prostate among men (N=277, 1.8%) and breast among women (N=187, 1.2%). Time dependent survival analysis showed that subjects who developed CVD during follow up were 60% more likely to develop cancer (95% Confidence Interval [CI] 1.3–1.95, p&amp;lt;0.001). However, after adjustment for known predictors of cancer, the association of incident CVD with cancer diagnosis was no longer significant (p=0.21). Interaction analysis demonstrated that the association of incident CVD with the risk of future cancer diagnosis was age dependent such that in younger subjects (&amp;lt;50 years; N=7,649) incident CVD was associated with a significant 2 fold increased risk of subsequent cancer diagnosis (95% CI 1.2–3.6, p=0.014) while in older subjects incident CVD was not associated with increased risk of cancer in the multivariable model (p for interaction =0.035; Figure 1). Conclusions Incident CVD is independently associated with 2-fold increased risk of subsequent cancer diagnosis among young adults. Our analysis underscores the importance of cancer surveillance among young patients following a CVD event. Figure 1 Funding Acknowledgement Type of funding source: None </jats:sec

Violent Fluid-Structure Interaction simulations using a coupled SPH/FEM method

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