[en] The reversible redox potential is established for the NO₂⁺/NO₂ couple by the cyclic voltammetric (CV) examination of the reduction of the nitronium ion as well as the microscopic reverse oxidation of nitrogen dioxide. The facile association of NO₂ and dissociation of N₂O₄ are specifically included in the electrode kinetics by the successful computer simulation of the cyclic voltammograms at relatively slow and fast CV scan rates. The kinetics of the N₂O₄ dissociation (k₁) and NO₂ association (k₂) are determined with the aid of single-step chronoamperometry by developing the theoretical working curves based on the CE(mono) mechanism in Scheme II. The strong dependence of the redox potential on the medium is associated with significant NO₂⁺ coordination, as shown by the linear correlation with Gutmann's donor number of the solvent. The heterogeneous rate constant (k_s) for electron transfer to NO₂⁺ is found to be faster than k_s for NO⁺, despite a significantly enhanced value of the intrinsic reorganization energy of NO₂⁺ compared to NO⁺ for outer-sphere electron transfer based on the Marcus model

[en] This conference dealt with 3 main topics: analytical innovation in separation processes (hyphenated techniques, analytical chips,...), actinide recycling (extraction, interfaces, processes,...) and chemistry and thermodynamics of actinides. This document is composed of the slides of the presentations

[en] The Earth has to face more and more devastating extreme events. Between 1970 and 2009, at the worldwide scale, the 25 most costly catastrophes all took place after 1987, and for more than half of them after 2001. Among these 25 catastrophes, 23 were linked to climate conditions. France was not spared: the December 1999 storms led to 88 deaths, deprived 3.5 million households of electricity and costed more than 9 billion euros. The 2003 heat wave led to about 15000 supernumerary deaths between August 1 and August 20. The recent Xynthia storm, with its flood barrier ruptures, provoked 53 deaths in addition to many other tragedies that took place in areas liable to flooding. In the present day context of climate change, we know that we must be prepared to even more dangerous events, sometimes unexpected before. These events can have amplified effects because of the urban development, the overpopulation of coastal areas and the anthropization of natural environments. They represent real 'poverty traps' for the poorest countries of the Earth. The anticipation need is real but is our country ready to answer it? Does it have a sufficient contribution to international actions aiming at reducing risks? Is his scientific information suitable? France is not less vulnerable than other countries. It must reinforce its prevention, its response and resilience capacities in the framework of integrated policies of catastrophes risk management as well as in the framework of climate change adaptation plans. This reinforcement supposes the development of vigilance systems with a better risk coverage and benefiting by the advances gained in the meteorology and health domains. It supposes a town and country planning allowing to improve the viability of ecological and social systems - in particular by protecting their diversity. Finally, this reinforcement requires inciting financial coverage solutions for catastrophes prevention and for their management once they have taken place. A permanent education effort is necessary both for the public and for the new generations. This requires excellence federating research programs based on quality data, on climatic and hydrologic models validation, and on the integration in these models of the knowledge gained from biological, human and social sciences. Investing in such programs has become a necessity. (J.S.)

[en] The detection of human antibodies of Multiple Sclerosis patients was investigated based on the electrochemical oxidation of a synthetic antigenic probe, a glycopeptide Fc-CSF114(Glc) bearing a ferrocenyl moiety. Electrochemical measurements were carried out at platinum microband electrodes without any electrode surface modification. A microfluidic device was designed in order to both minimize peptide consumption and increase the number of experiments with low volumes of samples. The specific interactions between Fc-CSF114(Glc) and antibodies were evidenced through comparison with electrochemical responses obtained from the ferrocenyl unglycosylated peptide Fc-CSF114 used as negative control. The interactions between Fc-CSF114(Glc) and autoantibodies were characterized by a shift of the oxidation potential towards positive values. A mechanism for peptide oxidation was proposed based on a diffusion control of mass transport and the formation of adsorbed layers able to mediate electron transfer. Results showed efficient antigen-antibody recognition without any electrode grafting or further addition of labels in solution. Preliminary tests using human sera from Multiple Sclerosis patients and healthy donors validated this new approach aimed at developing innovative and fast diagnostic tools, based on electrochemical synthetic antigenic probes