EFFECTS ON PRESSURE ON THE SPECTRA, LIFETIMES AND ENERGY TRANSFER OF Eu P5O14, Tb P5O14 AND Eu1-xTbxP5O14

L'effet de la pression sur la fluorescence des ions Tb3+ et Eu3+ dans des cristaux mixtes Tbx Eu1-x P5O14 est étudié jusqu'à 210 kbars. Un fort transfert d'énergie Tb3+ → Eu3+ est observé et on montre que l'effet de la pression sur ce transfert est gouverné par une relaxation diffusion-limité. En utilisant la spectroscopie résolue dans le temps sous haute pression on trouve que ce transfert est plus rapide avec la pression.The effect of pressure (up to 210 kbars) on the fluorescence of Tb3+ and Eu3+ ions in the mixed single crystals Tbx Eu1-x P5O14 is investigated. A strong Tb3+ → Eu3+ energy transfer is observed and the pressure dependence of this transfer is shown to be governed by diffusion-limited relaxation. Using time-resolved spectroscopy under high pressure this energy transfer is found to be faster with pressure

Luminescence properties of Ni2+ in CsCdBr3

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Transdermal drug delivery system: Active method for enhancing and controlling lidocaine hydrochloride diffusion

International audienceThe objective of this study is to determine the effect of iontophoresis on the transport of lidocaine hydrochloride (2%, w/w) across ear pig skin. Our project consists of the development of a transdermal drug delivery system (TDDS). The system is designed as a reusable electronic patch where micropump, reservoir, sensors and Bluetooth communication are integrated. Therefore, quantify the iontophoretic diffusion and investigate the effect of different current densities in enhancing and controlling drug delivery is a primordial step. In vitro iontophoresis experiments were conducted using Franz diffusion cells. Iontophoresis was applied for 30 minutes at current density of 0.25, 0.5 and 0.75 mA/cm2. Samples (1 mL) were withdrawn every 30 minutes from the receptor compartment and replaced with fresh buffer and then analyzed using High Performance Liquid Chromatography (HPLC). The amount of lidocaine HCl delivered was 247 ± 19, 199 ± 14 and 115 ± 7.11 μg/cm2 for 0.75, 0.5 and 0.25 mA/cm2 respectively and 25.6 ± 3.02 μg/cm2 for passive diffusion. The amount is influenced by current density, and could be therefore enhanced, predicted and controlled by those parameters

Influence of Structural Parameters on the Self-Association Properties of Anti-HIV Catanionic Dendrimers

International audienceThe self-association properties of anti-HIV catanionic dendrimers as multivalent galactosylceramide (GalCer)-derived inhibitors are presented. The study was designed to elucidate the origin of the relatively high cytotoxicity values of these anti-HIV catanionic dendrimers, which have previously been found to exhibit in vitro anti-HIV activity in the submicromolar range. The physicochemical properties of these catanionic dendrimers were studied to tentatively correlate the structural parameters with self-association and biological properties. We can conclude from this study that the absence of correlation between the hydrophobicity and the cytotoxicity of the catanionic systems could be explained by the partial segregation of the different partners of the catanionic entities