A multi-redox responsive cyanometalate-based metallogel

A tetrathiafulvalene (TTF) based tridentate ligand (-(4’-methyl-4,5-di-n-dodecylthylthiotetrathiafulvalene-5’-ylthio)-’-[tris-2,2,2-(1-pyrazolyl)ethoxy]-p-xylene) (L) with long-chain alkyl moieties was prepared in order to obtain a new multi-redox active gelator based on a mixed-metal octanuclear complex [FeIII4NiII4(CN)12(tp)4(L)4](BF4)4 (1). The magnetism, electrochemistry and gelation behaviour of 1 were studied and 1,2-dichlorobenzene solutions of 1 are shown to display thermoreversible gelation behaviour at room temperature. Furthermore, the gel phase of 1 is shown to undergo room-temperature gel-to-sol transformations induced by both the oxidation and reduction of the gelator complex by F4TCNQ or [FeII(Cp*)2], respectively

La « bande à Schnegg » : examen d’un groupe de sculpteurs indépendants

The “bande à Schnegg” : scrutinizing a group of independent sculptors. The phrase “la bande à Schnegg”, invented by critic Louis Vauxcelles en 1913, must be explained. At first, it was a group of independent sculptors assembling around Victor Schnegg, Rodin’s collaborator, who died in 1909. Without ever constituting a stable and exclusive society, these sculptors (essentially Gaston Schnegg,Jane Poupelet, Robert Wlérick, then Alfred Halou, François Pompon and Charles Despiau) shared a taste for fine work, mainly stone-carving, and sought simple forms drawn from nature. Their influence will span between the two World Wars and their works will often be linked to official architecture.Placin-Geay Amandine. La « bande à Schnegg » : examen d’un groupe de sculpteurs indépendants. In: Histoire de l'art, N°53, 2003. Affinités : L’artiste et son public. pp. 45-55

Melatonin modulates metabolic adaptation of pancreatic stellate cells subjected to hypoxia

Pancreatic stellate cells (PSCs), the main cell type responsible for the development of fibrosis in pancreatic cancer, proliferate actively under hypoxia. Melatonin has received attention as a potential antifibrotic agent due to its anti-proliferative actions on PSCs. In this work, we investigated the activation of the PI3K/Akt/mTOR pathway and the metabolic adaptations that PSCs undergo under hypoxic conditions, as well as the probable modulation by melatonin. Incubation of cells under hypoxia induced an increase in cell proliferation, and in the expression of alpha-smooth muscle actin and of collagen type 1. In addition, an increase in the phosphorylation of Akt was observed, whereas a decrease in the phosphorylation of PTEN and GSK-3b was noted. The phos-phorylation of mTOR and its substrate p70 S6K was decreased under hypoxia. Treatment of PSCs with melatonin under hypoxia diminished cell proliferation, the levels of alpha-smooth muscle actin and of collagen type 1, the phosphorylation of Akt and increased phosphorylation of mTOR. Mitochondrial activity decreased in PSCs under hypoxia. A glycolytic shift was observed. Melatonin further decreased mitochondrial activity. Under hypoxia, no increase in autophagic flux was noted. However, melatonin treatment induced autophagy activation. Never-theless, inhibition of this process did not induce detectable changes in the viability of cells treated with mela-tonin. We conclude that PSCs undergo metabolic adaptation under hypoxia that might help them survive and that pharmacological concentrations of melatonin modulate cell responses to hypoxia. Our results contribute to the knowledge of the mechanisms by which melatonin could modulate fibrosis within the pancreas

Engineering of small molecule organogels by design of the nanometer structure of fiber networks

The influence of a nonionic surfactant polyoxyethylene sirbitan monooelate on the structure of the fiber networks of organogels was investigated and the effects of these surfactants on the rheological properties of the gels were studied. The results show that the network is formed by transient entanglement of individual fibers and the addition of tiny amount of a nonionic surfactant Tween 80 promotes the formation of inter-connected fiber network structures. The fibers in absence and presence of surfactant have same XRD pattern as that of the gelator powders signifying that Tween 80 does not affect the crystalline nature of fibers. The macroscopic properties of the gel shows that an increase in surfactant concentration increases the elasticity of gels and then approaches a constant level. The results also show that in a small molecule of organogel, a shorter correlation length gives higher elasticity to the gel