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Tissue infiltration of macrophages, although critical for innate immunity, is also involved in pathologies, such as chronic inflammation and cancer. In vivo, macrophages migrate mostly in a constrained three-dimensional (3D) environment. However, in vitro studies, mainly focused on two dimensions, do not provide meaningful clues about the mechanisms(More)
We show experimentally and theoretically that reaction systems characterized by a slow induction period followed by a fast evolution to equilibrium can readily generate "spatial bistability" when operated in thin gel reactors diffusively fed from one side. This phenomenon which corresponds to the coexistence of two different stable steady states, not(More)
The rheological properties of a new type of colloidal dispersion based on nanoparticles of gelled oil have been characterized. The nanoparticles (mean diameter approximately 250 nm) were viscoelastic droplets of dicaprylyl ether gelled by 12-hydroxystearic acid (HSA) and were stabilized in aqueous solutions by cetyltrimethylammonium bromide. The effects of(More)
The first experimental evidence of a chemomechanical mechanism leading to morphogenetic instabilities is demonstrated experimentally. The system consists of a pH-responsive gel that swells at high pH and shrinks at low pH, and a bistable reaction system exhibiting an acid steady state (pH approximately 2) and an alkaline steady state (pH approximately 10).(More)
A photo-controlled and quasi-reversible switch of the luminescence of hexadecylamine-coated ZnO nanocrystals (ZnO@HDA Ncs) is operated via a molecular photoswitch (dithienylethene, DTE). The interaction between the DTE switch and the ZnO@HDA Ncs is thoroughly investigated using NMR spectroscopy techniques, including DOSY and NOESY, showing that the DTE(More)
Di- and triblock non-ionic copolymers based on poly(ethylene oxide) and poly(propylene oxide) were studied for the stabilization of nanoparticles in water at high ionic strength. The effect of the molecular architecture (di- vs. triblock) of these amphiphilic copolymers was investigated by using gold nanoparticles (AuNPs) as probes for colloidal stability.(More)
We show both experimentally and numerically that the time scales separation introduced by long range activation can induce oscillations and excitability in nonequilibrium reaction-diffusion systems that would otherwise only exhibit bistability. Namely, we show that in the chlorite-tetrathionate reaction, where the autocatalytic species H+ diffuses faster(More)