6 results match your criteria: "2 University of Hamburg[Affiliation]"

Background: Existing research shows significant effects of pedometer interventions on students' physical activity (PA). The current study investigates motivational aspects of quantitative increases in PA in the course of a school-based pedometer intervention for adolescents using qualitative data analysis. In addition, critical issues regarding pedometer use in adolescence were examined.

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Imaging single cells in a beam of live cyanobacteria with an X-ray laser.

Nat Commun

February 2015

Laboratory of Molecular Biophysics, Department of Cell and Molecular Biology, Uppsala University, Husargatan 3 (Box 596), SE-751 24 Uppsala, Sweden.

There exists a conspicuous gap of knowledge about the organization of life at mesoscopic levels. Ultra-fast coherent diffractive imaging with X-ray free-electron lasers can probe structures at the relevant length scales and may reach sub-nanometer resolution on micron-sized living cells. Here we show that we can introduce a beam of aerosolised cyanobacteria into the focus of the Linac Coherent Light Source and record diffraction patterns from individual living cells at very low noise levels and at high hit ratios.

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Nonlinear lattice dynamics as a basis for enhanced superconductivity in YBa2Cu3O6.5.

Nature

December 2014

1] Max Planck Institute for the Structure and Dynamics of Matter, 22761 Hamburg, Germany [2] University of Hamburg, 22761 Hamburg, Germany [3] Center for Free-Electron Laser Science (CFEL), 22761 Hamburg, Germany [4] Department of Physics, University of Oxford, Clarendon Laboratory, Oxford OX1 3PU, UK.

Terahertz-frequency optical pulses can resonantly drive selected vibrational modes in solids and deform their crystal structures. In complex oxides, this method has been used to melt electronic order, drive insulator-to-metal transitions and induce superconductivity. Strikingly, coherent interlayer transport strongly reminiscent of superconductivity can be transiently induced up to room temperature (300 kelvin) in YBa2Cu3O6+x (refs 9, 10).

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High-quality protein crystals of suitable size are an important prerequisite for applying X-ray crystallography to determine the 3-dimensional structure of proteins. However, it is often difficult to obtain protein crystals of appropriate size and quality because nucleation and growth processes can be unsuccessful. Here, we show that by adsorbing proteins onto porous polystyrene-divinylbenzene microspheres (SDB) floating on the surface of the crystallisation solution, a localised high supersaturation region at the surface of the microspheres and a low supersaturation region below the microspheres can coexist in a single solution.

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X-ray holography with a customizable reference.

Nat Commun

August 2014

1] Center for Free-Electron Laser Science, DESY, Hamburg 22607, Germany [2] University of Hamburg, Luruper Chaussee 149, Hamburg 22761, Germany.

In X-ray Fourier-transform holography, images are formed by exploiting the interference pattern between the X-rays scattered from the sample and a known reference wave. To date, this technique has only been possible with a limited set of special reference waves. We demonstrate X-ray Fourier-transform holography with an almost unrestricted choice for the reference wave, permitting experimental geometries to be designed according to the needs of each experiment and opening up new avenues to optimize signal-to-noise and resolution.

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Photosynthesis, a process catalysed by plants, algae and cyanobacteria converts sunlight to energy thus sustaining all higher life on Earth. Two large membrane protein complexes, photosystem I and II (PSI and PSII), act in series to catalyse the light-driven reactions in photosynthesis. PSII catalyses the light-driven water splitting process, which maintains the Earth's oxygenic atmosphere.

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