Solid-solid transitions between crystals follow diffusive nucleation, or various diffusionless transitions, but these kinetics are difficult to predict and observe. Here we observed the rich kinetics of transitions from square lattices to triangular lattices in tunable colloidal thin films with single-particle dynamics by video microscopy. Applying a small pressure gradient in defect-free regio...

Metabolite diffusion in tissues produces gradients and heterogeneous microenvironments that are not captured in standard 2D cell culture models. Here we describe restricted exchange environment chambers (REECs) in which diffusive gradients are formed and manipulated on length scales approximating those found in vivo. In REECs, cells are grown in 2D in an asymmetric chamber (<50 μL) formed betwe...

In this paper, we demonstrate, for the first time, how an external osmotic gradient can be used to regulate diffusion of solutes across a lipid membrane. We present experimental and theoretical studies of the transport of different solutes across a monoolein membrane in the presence of an external osmotic gradient. The osmotic gradient introduces phase transformations in the membrane, and it ca...

This paper analyzes the properties of a two-field critical gradient model that couples a heat equation to an evolution equation for the turbulence intensity. It is shown that the dynamics of a perturbation is ballistic or diffusive depending on the shape of the pulse and also on the distance of the temperature gradient to the instability threshold. This dual character appears in the linear resp...

We consider the resolution of an inverse problem for the identification of some reduced nonlinear diffusive models. The modal identification method is dealt with along with a gradient-type optimization method. Two distinct approaches are considered and compared. On one hand the classical finite differences approach and, on the other hand, the adjoint method for the computation of the objective ...

We study asymptotic limits of reversible random walks on tessellations via a variational approach which relies specific generalized gradient flow formulation the corresponding forward Kolmogorov equation. establish sufficient conditions sequences and jump intensities under sequence converges to diffusion process with possibly spatially dependent tensor.

Since biomolecular concentration gradients are an important factor in various biological phenomena, many concentration gradient generators utilizing microfluidic techniques have been devised in order to establish stable in vitro biomolecular concentration gradients, each with their own strengths. However, all the fundamental issues, simplicity in apparatus, dynamic controllability, and convecti...

The response to perturbations of a simplified transport model is studied. The model is used as a paradigmatic example of transport controlled by a critical gradient. Long-time system behaviour is diffusive when most of the system is sub-critical. However, when the critical mechanism becomes significant, it is observed to dominate the system behaviour at both shortand long-time scales. While the...

In this paper, the effect of magnetic field on double-diffusive convection in couple-stress fluid saturating a porous medium is considered. By applying linear stability theory and normal mode analysis method, a necessary condition is derived which states that the viscoelastic double-diffusive convection at marginal state, cannot manifest as stationary convection if the thermal Rayleigh number R...