Jérémie Palacci

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Spontaneous formation of colonies of bacteria or flocks of birds are examples of self-organization in active living matter. Here, we demonstrate a form of self-organization from nonequilibrium driving forces in a suspension of synthetic photoactivated colloidal particles. They lead to two-dimensional "living crystals," which form, break, explode, and(More)
In this Letter, we investigate experimentally the nonequilibrium steady state of an active colloidal suspension under gravity field. The active particles are made of chemically powered colloids, showing self propulsion in the presence of an added fuel, here hydrogen peroxide. The active suspension is studied in a dedicated microfluidic device, made of(More)
Self-propelled particles can exhibit surprising non-equilibrium behaviors, and how they interact with obstacles or boundaries remains an important open problem. Here we show that chemically propelled micro-rods can be captured, with little change in their speed, into close orbits around solid spheres resting on or near a horizontal plane. We show that this(More)
Biological systems often involve the self-assembly of basic components into complex and functioning structures. Artificial systems that mimic such processes can provide a well-controlled setting to explore the principles involved and also synthesize useful micromachines. Our experiments show that immotile, but active, components self-assemble into two types(More)
Ketamine, 40 ml 0.5% solution, was used in the technique of intravenous regional anaesthesia in 14 patients undergoing upper limb surgery. Satisfactory analgesia was obtained in 12 of the patients. The method is limited by the fact that all patients became unconscious within a few minutes of tourniquet release, and that this could not be prevented by(More)
In this Letter, we explore experimentally the phase behavior of a dense active suspension of self-propelled colloids. In addition to a solidlike and gaslike phase observed for high and low densities, a novel cluster phase is reported at intermediate densities. This takes the form of a stationary assembly of dense aggregates-resulting from a permanent(More)
Several animal studies have demonstrated that pain is modulated by spinal mechanisms involving prostaglandins and that acetylsalicylic acid (ASA) administered intrathecally has an analgesic effect. We report our experience of this treatment in 60 patients with proven and advanced cancer. An isobaric solution of lysine acetylsalicylate was administered by(More)
In this Letter, we characterize experimentally the diffusiophoretic motion of colloids and lambda-DNA toward higher concentration of solutes, using microfluidic technology to build spatially and temporally controlled concentration gradients. We then demonstrate that segregation and spatial patterning of the particles can be achieved from temporal variations(More)
We introduce a self-propelled colloidal hematite docker that can be steered to a small particle cargo many times its size, dock, transport the cargo to a remote location, and then release it. The self-propulsion and docking are reversible and activated by visible light. The docker can be steered either by a weak uniform magnetic field or by nanoscale tracks(More)
during nitrous oxide-fentanyl and nitrous oxide-isoflurane anaesthesia. Br. J. Anaesth, 55, 67S. Soter, N. A., Wasserman, S. I., Austen, K. F. and McFadden, E. R. (1980). Release of mast cell mediators and alterations in lung function in patients with cholinergic urticaria. N. Engl. J. Med., 302, 604. Twohig, M. M., Ward, S., and Corall, I. M. (1983).(More)