In: Journal of Statistical Mechanics: Theory and Experiment, 2016, vol. 2016, no. 9, p. 094003
We investigate structural and dynamical properties of moderately polydisperse emulsions across an extended range of droplet volume fractions phgr, encompassing fluid and glassy states up to jamming. Combining experiments and simulations, we show that when phgr approaches the glass transition volume fraction ${{\phi}_{g}}$ , dynamical heterogeneities and amorphous order arise within the...
|
In: Rheologica Acta, 2016, vol. 55, no. 8, p. 683–697
We develop a free energy model that describes two key thermodynamic properties, the osmotic pressure Π and the linear elastic shear modulus G′p (i.e. plateau storage modulus), of concentrated monodisperse emulsions which have isotropic, disordered, droplet structures, and are stabilized using ionic surfactants. This model effectively incorporates the concept of random close packing or...
|
In: Physical Review Letters, 2016, vol. 117, no. 5, p. 053902
We study photonic band gap formation in two-dimensional high-refractive-index disordered materials where the dielectric structure is derived from packing disks in real and reciprocal space. Numerical calculations of the photonic density of states demonstrate the presence of a band gap for all polarizations in both cases. We find that the band gap width is controlled by the increase in...
|
In: Frontiers in Cellular Neuroscience, 2016, p. 142
Understanding synaptic connectivity and plasticity within brain circuits and their relationship to learning and behavior is a fundamental quest in neuroscience. Visualizing the fine details of synapses using optical microscopy remains however a major technical challenge. Super resolution microscopy opens the possibility to reveal molecular features of synapses beyond the diffraction limit....
|
In: Colloids and Surfaces A: Physicochemical and Engineering Aspects, 2016, vol. 499, p. 18–23
Hierarchical polymer structures such as pNIPAM microgels have been extensively studied for their ability to undergo structural and physical transformations that can be controlled by external stimuli such as temperature, pH or solvent composition. However, a direct three-dimensional visualization of individual particles in-situ has so far been hindered by insufficient resolution, with optical...
|
In: Journal of Physics: Condensed Matter, 2016, vol. 28, no. 13, p. 135101
Self-diffusion and radial distribution functions are studied in a strongly confined Lennard-Jones fluid. Surprisingly, in the solid–liquid phase transition region, where the system exhibits dynamic coexistence, the self-diffusion constants are shown to present up to three-fold variations from solid to liquid phases at fixed temperature, while the radial distribution function corresponding...
|
In: Scientific Reports, 2016, vol. 6, p. 21818
Photonic crystal materials are based on a periodic modulation of the dielectric constant on length scales comparable to the wavelength of light. These materials can exhibit photonic band gaps; frequency regions for which the propagation of electromagnetic radiation is forbidden due to the depletion of the density of states. In order to exhibit a full band gap, 3D PCs must present a threshold...
|
In: Optics Express, 2015, vol. 23, no. 23, p. 29342
We study the lifetime of two common fluorescent dye molecules from the Alexa Fluor NHS Ester family dissolved in water in an opaque aqueous dispersion of dielectric polystyrene nanoparticles. We investigate the role of the dispersion composition by varying the particle concentration and adding SDS (sodium dodecyl sulfate) surfactant molecules. The observed strong changes in lifetime of Alexa 430...
|
In: Proceedings SPIE, 2015, vol. 9540, p. 954008–954008–9
We present an improved Laser speckle imaging approach to investigate the cerebral blood flow response following function stimulation of a single vibrissa. By synchronising speckle analysis with the cardiac cycle we are able to obtain robust averaging of the correlation signals while at the same time removing the contributions due to the pulsation of blood flow and associated tissue adaptation....
|
In: Nature Communications, 2015, vol. 6, p. 7460
Appropriate combinations of laser beams can be used to trap and manipulate small particles with optical tweezers as well as to induce significant optical binding forces between particles. These interaction forces are usually strongly anisotropic depending on the interference landscape of the external fields. This is in contrast with the familiar isotropic, translationally invariant, van der Waals...
|