Dominique Ernst

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BACKGROUND As an important modifiable lifestyle factor in osteoporosis prevention, physical activity has been shown to positively influence bone mass accrual during growth. We have previously shown that a nine month general school based physical activity intervention increased bone mineral content (BMC) and density (aBMD) in primary school children. From a(More)
BACKGROUND School-based intervention studies promoting a healthy lifestyle have shown favorable immediate health effects. However, there is a striking paucity on long-term follow-ups. The aim of this study was therefore to assess the 3 yr-follow-up of a cluster-randomized controlled school-based physical activity program over nine month with beneficial(More)
Fluids for SPT experiments were obtained by dissolving dextran (500 kDa, Sigma) and sucrose (342 Da, Roth) in millipore water at concentrations of about 430 mg/ml (30% w/w) and 1500 mg/ml (60% w/w), respectively. Rhodamine-tagged tracer beads (50 nm, Polysciences) were added from a predissolved solution, resulting in a typical concentration of about 2 pM.(More)
The purpose of this study was to assess the validity of accelerometers using force plates (i.e., ground reaction force (GRF)) during the performance of different tasks of daily physical activity in children. Thirteen children (10.1 (range 5.4-15.7) years, 3 girls) wore two accelerometers (ActiGraph GT3X+ (ACT), GENEA (GEN)) at the hip that provide raw(More)
Many reactions in complex fluids, e.g. signaling cascades in the cytoplasm of living cells, are governed by a diffusion-driven encounter of reactants. Yet, diffusion in complex fluids often exhibits an anomalous characteristic ('subdiffusion'). Since different types of subdiffusion have distinct effects on timing and equilibria of chemical reactions, a(More)
We provide experimental results on the accuracy of diffusion coefficients obtained by a mean squared displacement (MSD) analysis of single-particle trajectories. We have recorded very long trajectories comprising more than 1.5 × 10(5) data points and decomposed these long trajectories into shorter segments providing us with ensembles of trajectories of(More)
We recorded fluorescence time traces, and simultaneously either the fluorescence lifetime or the emission spectra from single perylene bisimide (PBI) dimers embedded in a polystyrene matrix. In these traces three distinct intensity levels can be distinguished, which reflect the photo-induced radicalisation of one of the perylene subunits. Differences in the(More)
We report on an experimental setup for single-particle orbit tracking, which allows following fluorescent nanoparticles for more than 10 min with a temporal resolution of 4 ms and a dynamic position accuracy of better than 10 nm. On a model sample--20 nm sized fluorescent polymer beads in glycerol--we will illustrate how artifacts caused by unavoidable(More)
The size distribution of nanoparticles can be determined by single-particle tracking. This yields the mean-squared displacement (MSD) as a function of the lag time, and for normal diffusion the slope of this curve is directly related to the diffusion coefficient or via the Stokes-Einstein relation to the particle size. Here we demonstrate how the(More)
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