University of Rennes

About: University of Rennes is a education organization based out in Rennes, France. It is known for research contribution in the topics: Population & Catalysis. The organization has 18404 authors who have published 40374 publications receiving 995327 citations.

The Usf-1 transcription factor is a novel target for the stress-responsive p38 kinase and mediates UV-induced Tyrosinase expression.

Abstract: The stress-activated signalling cascade leading to phosphorylation of the p38 family of kinases plays a crucial role during development and in the cellular response to a wide variety of stress-inducing agents. Although alterations in gene expression characteristic of the stress response require the regulation of key transcription factors by the p38 family, few downstream targets for this signalling pathway have been identified. By examining the ability of pigment cells to respond to UV irradiation as part of the UV-induced tanning response, we show that while the microphthalmia-associated transcription factor Mitf regulates basal Tyrosinase expression, it is the ubiquitous basic helix–loop–helix-leucine zipper transcription factor Usf-1 that is required for the UV activation of the Tyrosinase promoter. Consistent with this we demonstrate that Usf-1 is phosphorylated and activated by the stress-responsive p38 kinase. The results suggest that activation of Usf-1 by p38 at a wide variety of viral and cellular promoters will provide a link between stimuli as diverse as UV irradiation, glucose, viral infection and pro-inflammatory cytokines, and the changes in gene expression associated with the stress response.

On the origin of the remarkable stability of aqueous foams stabilised by nanoparticles: link with microscopic surface properties

Abstract: We have performed a quantitative study of the coarsening of foams stabilised by partially hydrophobic silica nanoparticles. We have used a variety of techniques: optical and electron microscopy, microfluidics, and multiple light scattering. Using earlier studies of planar particle monolayers, we have been able to correlate the interfacial properties and the macroscopic temporal evolution of the foam. This has shed light on the origin of the absence of coarsening of particle-stabilised foams. Such particle-stabilised foams appear to be the only known foam system where coarsening is inhibited by surface elasticity.

The age of the Fortescue Group, Hamersley Basin, Western Australia, from ion microprobe zircon U-Pb results

Abstract: U‐Pb zircon ages are reported for nine samples from the volcano‐sedimentary Fortescue Group, the lowest of the three groups (Fortescue, Hamersley, Turee Creek) in the Hamersley Basin, and for a 10th sample from the Munni Munni Complex, which immediately underlies the basal unconformity of the Fortescue Group. Three widely separated felsic lava or tuff samples close to the base of the group give ages of 2775 ± 10, 2764 ± 8 and 2763 ± 13 Ma (all errors 2σ). Two other stratigraphically higher samples give ages of 2760 ± 10 and 2756 ± 8 Ma. The latter, from the Bamboo Creek Porphyry, is close to Pidgeon's (1984) published result of 2768 ± 16 Ma for the related Spinaway Porphyry. The mean of all six results, 2765 Ma, is the best estimate of the age of an abrupt initiating volcanic event in the Fortescue Group; the (short) duration of this bimodal volcanic event is not precisely defined by these results, although an age of 2715 ± 6 Ma for the youngest zircon population of the volcaniclastic Pillingini Tuff sets...