159 research outputs found
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Prototyping a Context-Aware Framework for Pervasive Entertainment Applications
Force-clamp experiments reveal the free energy profile and diffusion coefficient of the collapse of proteins
We present force-clamp data on the collapse of ubiquitin polyproteins in
response to a quench in the force. These nonequilibrium trajectories are
analyzed using a general method based on a diffusive assumption of the
end-to-end length to reconstruct a downhill free energy profile at 5pN and an
energy plateau at 10pN with a slow diffusion coefficient on the order
of~100nm^2/s. The shape of the free energy and its linear scaling with the
protein length give validity to a physical model for the collapse. However, the
length independent diffusion coefficient suggests that internal rather than
viscous friction dominates and thermal noise is needed to capture the
variability in the measured times to collapse.Comment: 12 pages, 4 figure
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Recent advances in the user evaluation methods and studies of non-photorealistic visualisation and rendering techniques
Biomimetic emulsions reveal the effect of homeostatic pressure on cell-cell adhesion
Cell-cell contacts in tissues are continuously subject to mechanical forces
due to homeostatic pressure and active cytoskeleton dynamics. While much is
known about the molecular pathways of adhesion, the role of mechanics is less
well understood. To isolate the role of pressure we present a dense packing of
functionalized emulsion droplets in which surface interactions are tuned to
mimic those of real cells. By visualizing the microstructure in 3D we find that
a threshold compression force is necessary to overcome electrostatic repulsion
and surface elasticity and establish protein-mediated adhesion. Varying the
droplet interaction potential maps out a phase diagram for adhesion as a
function of force and salt concentration. Remarkably, fitting the data with our
theoretical model predicts binder concentrations in the adhesion areas that are
similar to those found in real cells. Moreover, we quantify the adhesion size
dependence on the applied force and thus reveal adhesion strengthening with
increasing homeostatic pressure even in the absence of active cellular
processes. This biomimetic approach reveals the physical origin of
pressure-sensitive adhesion and its strength across cell-cell junctions.Comment: 20 pages, 5 figure
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Towards Rapid Generation and Visualisation of Large 3D Urban Landscapes for Mobile Device Navigation
In this paper a procedural 3D modelling solution for mobile devices is presented based on scripting algorithms allowing for both the automatic and also semi-automatic creation of photorealistic quality virtual urban content. The combination of aerial images, GIS data, 2D ground maps and terrestrial photographs as input data coupled with a user-friendly customized interface permits the automatic and interactive generation of large-scale, accurate, georeferenced and fully-textured 3D virtual city content, content that can be specially optimized for use with mobile devices but also with navigational tasks in mind. Furthermore, a user-centred mobile virtual reality (VR) visualisation and interaction tool operating on PDAs (Personal Digital Assistants) for pedestrian navigation is also discussed. Via this engine, the import and display of various navigational file formats (2D and 3D) is supported, including a comprehensive front-end user-friendly graphical user interface providing immersive virtual 3D navigation
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A Framework for the Development of Online, Location-Specific, Expressive 3D Social Worlds
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