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Biomedical subjects

M P Pileni

Publications and source records attributed to M P Pileni.

7 recordsLinked to original sources
PubMed2001

Supra-aggregates.

Mixtures of oil (isooctane), water, and a double-chained ionic surfactant, Cu(AOT)2 [copper(II) bis(2-ethylhexyl)sulfosuccinate] form equilibrium phases consisting of spontaneous emulsions thermodynamically stable systems. The experimental conditions are such that the head polar group of the surfactant is totally hydrated. The emulsion droplets are comprised of supra aggregates, lamellar spherulites in which interior and exterior are bicontinuous microemulsions. The microstructures and component ratios can be predicted from elementary considerations that require only the notion of local and global packing constraints. The phenomenon of supra aggregation, microphases within any topologically closed container, in equilibrium with an external phase, appears quite general. The results throw some light on the meaning of 'phase' in mesostructured fluids.

Journal Article↗
PubMed2000

Coupled plasmon modes in an ordered hexagonal monolayer of metal nanoparticles: a direct observation.

We report on the experimental observation of STM-induced photon emission in ultrahigh vacuum on a network of 4-nm silver spheres. The spheres are covered by a dielectric, electrically insulating, organic layer and deposited on Au(111). The bias-dependent spatial distribution of the photon emission rates reveals the electric-field distribution of the different coupled plasmon modes in this model.

Journal Article↗
PubMed1995

Lipase catalyzed esterification in AOT reverse micelles: a structural study.

AOT reverse micelles are used to cosolubilize hydrophilic and hydrophobic reactants of lipase catalysed esterification. Depending on the nature of the alcohol, a drastic change of the initial rate of the esterification is observed. A structural study of the micellar system with and without reactant is undertaken to explain the change in the activity with the various alcohols.

Catalysis↗
PubMed1991

Drastic change of reverse micellar structure by protein or enzyme addition.

On addition of cytochrome c to a AOT reverse micellar solution, the percolation process usually observed at high temperatures and surfactant concentrations, occurs at room temperature. This is observed either at relatively high water content at a given cytochrome c concentration or at low content on increasing the cytochrome c concentration. On increasing the water content a phase transition is observed with two optically transparent phases. A similar phase transition is observed on solubilizing various enzymes. The temperature of the transition appears to be strongly dependent on the location of the macromolecule in the reserve micelle.

Chymotrypsin↗
PubMed1977

A pulse-radiolysis study of the reaction of hydrated electrons with N'-formylkynurenine and related compounds: electron-transfer reactions with nucleic acid components.

The reactivity of N'-formylkynurenine (FK) derivatives towards eaq has been investigated. The reduced transient species have been characterized (lambda max approximately 340, 440 nm, epsilon lambda max approximately 3000-1000 M-1 cm-1, pKa approximately 7.8). Owing to the strong FK electron affinity, electron-transfer reactions occur from purine (except guanine) and pyrimidine electron adducts to FK (k approximately 2-7 x 10(9) M-1 s-1). As some FK derivatives bind to DNA (or polynucleotides) the protective effect of complexation on FK-DNA (or polynucleotides) adduct formation has been investigated.

DNA↗