Core-shell inversion by pH modulation in dynamic covalent micelles.

Dynamic covalent surfactants have been obtained by the reversible condensation of a hydrophobic aldehyde (ended by an ionic tip) with various neutral polyethylene glycol based hydrophilic amines. In water, the duality between the two hydrophilic domains (charged and neutral) leads to their segregation when the surfactants are self-assembled within micelles. Depending on the number of polyethylene glycol units, a core-shell inversion leading to a switching orientation of the ionic tips from the inside to the outside of the micelles has been demonstrated by a combination of scattering techniques. In competition experiments, when several amines of different pKas and hydrophilic polyethylene glycol chains are competing for the same aldehyde, it becomes possible to trigger this core-shell inversion by pH modulation and associated dynamic constitutional reorganization.

[From the analogic to the digital era: technical EEG progress for presurgical investigations of refractory partial epilepsies]. / De l'ère analogique à l'ère numérique: évolution des techniques électro-encéphalographiques dans le bilan préchirurgical des épilepsies partielles pharmacorésistantes.

Over the past two decades, exploration of epileptic patients has benefited from technological advances in electroencephalography. Computerized equipment can simultaneously retrieve cerebral electric activity and signs of the patient's ictal activity. The computer era has improved reliability, storage and analysis of the recorded data and provides easier communication tools for multidisciplinary staff and patient case studies. Therefore, an increasing number of patients could benefit from presurgical investigations and surgical treatment.

Al(30): A Giant Aluminum Polycation.

Simple hydrothermal treatment of the well-known aluminum polycation varepsilon-Al(13) produces the novel Al(30) structure (see picture), the largest polycation yet observed. Its characterization, by X-ray diffraction and NMR spectroscopy, also solved previously unassigned signals in (27)Al NMR spectra of other Al - O species.