Understanding charged vesicle suspensions as Wigner glasses: dynamical aspects.

Suspensions of charged vesicles in water with added salt are widespread in nature and industrial production. Here we investigate, via Brownian dynamics simulations, a model that grasps the key features of these systems, with bidisperse colloidal beads interacting via a hard-core and an electrostatic double layer potential. Our goal is to focus on a set of interaction parameters that is not generic but measured in recent experiments, and relevant for a class of consumer products, such as liquid fabric softeners. On increasing the volume fraction in a range relevant to real formulation, we show that the dynamics become progressively slower and heterogeneous, displaying the typical signatures of an approaching glass transition. On lowering the salt concentration, which corresponds to increasing the strength and range of the electrostatic repulsion, the emergence of glassy dynamics becomes significantly steeper, and, remarkably, occurs at volume fractions well below the hard-sphere glass transition. The volume fraction dependence of the structural relaxation time at different salt concentration is well described through a functional law inspired by a recently proposed model (Krausser et al 2015 Proc. Natl Acad. Sci. USA 112 13762). According to our results, the investigated system may be thought of as a Wigner glass, i.e. a low-density glassy state stabilized by long-range repulsive interactions. Overall, our study suggests that glassy dynamics plays an important role in controlling the stability of these suspensions.

Septic arthritis in children.

Osteoarticular infections are a form of diagnostic and therapeutic emergency in infants and children, even if relatively rare. Despite decades of experience with different protocols, and multiple clinical trials, today it is still difficult to determine what kind of antibiotics is really effective, what kind of associations are required, which is the optimal time range of a treatment, when and on which subjects to base the transition from a parenteral treatment to an oral one. Current philosophy aims more and more at reducing hospitalization and costs, and wants to decrease the discomfort in the family. The purpose of these guidelines is to promote a reasoned clinical and therapeutic approach, in a context of diagnostic probabilities that offer the best chance of success in reducing hospitalization with a rapid transition to an oral treatment, and then outpatient, and thus educing totally the processing time.