Université de Fribourg

Brushlike interactions between thermoresponsive microgel particles

Scheffold, Frank ; Díaz-Leyva, Pedro ; Reufer, Mathias ; Braham, Nasser Ben ; Lynch, Iseult ; Harden, James L.

In: Physical Review Letters, 2010, vol. 104, no. 12, p. 128304

Using a simplified microstructural picture we show that interactions between thermosensitive microgel particles can be described by a polymer brushlike corona decorating the dense core. The softness of the potential is set by the relative thickness L0 of the compliant corona with respect to the overall size of the swollen particle R. The elastic modulus in quenched solid phases derived from the...

Université de Fribourg

Improved in vivo two-photon imaging after blood replacement by perfluorocarbon

Haiss, F. ; Jolivet, R. ; Wyss, M. T. ; Reichold, J. ; Ben Braham, Nasser ; Scheffold, Frank ; Krafft, M. P. ; Weber, B.

In: The Journal of Physiology, 2009, vol. 587, p. 3153-3158

Two-photon microscopy is a powerful method in biomedical research that allows functional and anatomical imaging at a subcellular resolution in vivo. The technique is seriously hampered by absorption and scattering of light by blood, which prevents imaging through large vessels. Here, we demonstrate in the rat cerebral cortex that blood replacement by perfluorocarbon emulsion, a compound also used...

Université de Fribourg

The influence of the scattering anisotropy parameter on diffuse reflection of light

Pierrat, R. ; Ben Braham, Nasser ; Rojas-Ochoa, Luis Fernando ; Carminati, R. ; Scheffold, Frank

In: Optics Communications, 2008, vol. 281, no. 1, p. 18-22

We discuss the impact of the scattering anisotropy parameter on the path length distribution of multiply scattered light. A quantitative treatment based on the radiative transfer equation is compared to an extended photon diffusion formalism. We compare both models with diffusing-wave spectroscopy measurements using randomly polarized light.

See also: similar author names
1 Braham, Nasser Ben