Electrocatalysis Applied to Electrochemical Investigation in vivo

The potentialities of electrochemistry for in vivo measurements are discussed. The advantages of cyclic voltammetry at inert electrodes for this purpose are pointed out. The voltammetric response of blood serum is explained.Cysteine and ascorbic acid are shown as suitable electrochemical indicators for in vivo measurements. A method based on cyclic voltammetry of ascorbic acid as indicator is suggested for assessment of the blood circulation of kidney determined for transplantation

Electrocatalysis Applied to Electrochemical Investigation in vivo

The potentialities of electrochemistry for in vivo measurements are discussed. The advantages of cyclic voltammetry at inert electrodes for this purpose are pointed out. The voltammetric response of blood serum is explained.Cysteine and ascorbic acid are shown as suitable electrochemical indicators for in vivo measurements. A method based on cyclic voltammetry of ascorbic acid as indicator is suggested for assessment of the blood circulation of kidney determined for transplantation

Fluctuation-Dissipation-Theorem violation during the formation of a colloidal-glass

The relationship between the conductivity and the polarization noise is measured in a gel as a function of frequency in the range $1Hz - 40Hz$. It is found that at the beginning of the transition from a fluid like sol to a solid like gel the fluctuation dissipation theorem is strongly violated. The amplitude and the persistence time of this violation are decreasing functions of frequency. At the lowest frequencies of the measuring range it persists for times which are about 5% of the time needed to form the gel. This phenomenology is quite close to the recent theoretical predictions done for the violation of the fluctuation dissipation theorem in glassy systems.Comment: 6 pages + 4 figure

Intermittency in aging

The fluctuation-dissipation relation (FDR) is measured on the dielectric properties of a gel (Laponite) and of a polymer glass (polycarbonate). For the gel it is found that during the transition from a fluid-like to a solid-like state the fluctuation dissipation theorem is strongly violated. The amplitude and the persistence time of this violation are decreasing functions of frequency. Around $1Hz$ it may persist for several hours. A very similar behavior is observed in polycarbonate after a quench below the glass transition temperature. In both cases the origin of this violation is a highly intermittent dynamics characterized by large fluctuations. The relevance of these results for recent models of aging are discussed.Comment: Proceedings of "III workshop on non equilibrium phenomena" (Pisa 2002