Articolele autorului Roxana-Diana Pasca
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Behavior of mixed DMPC-cholesterol monolayers at the air/water interface

The phase behaviour of cholesterol (CHO) and dimyristoyl phosphatidyl choline (DMPC) monolayers at the air/water interface was investigated by surface pressure measurements using Langmuir technique. Compression isotherms and isobars as functions of composition were represented, and the surface compressibility modulus was calculated, in order to characterize the physical states of the monolayers. At a constant lateral surface pressure, the monolayers

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Inclusion complex of p-cyclodextrin and quercetin. Thermodynamic Approach

The complexation of β-cyclodextnn (βCD) and quercetin (Que) in aqueous alcoholic solutions is investigated by UV-Vis spectroscopy. Three different aqueous media, namely pH 3, unbuffered (pH 5.5) and pH 7, are used to vary the environmental conditions and the interaction between host (βCD) and guest (Que) molecules. The equilibrium constants for the formation of the inclusion βCD-Que complex are estimated from two different absorption bands and

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Surface potentials of cholesterol and dimyristoyl phosphatidylcholine monolayers at the air/water interface

The behaviour of cholesterol (CHO) and dimyristoyl phosphatidylcholine (DMPC), as well as of their mixed monolayers of various compositions has been investigated by surface potential (δV) measurements at the air/water interface for different surface pressures, using Langmuir technique coupled with the vibrating plate method. Isotherms of δV versus mean molecular area, A, at different cholesterol mole fractions, xCHO, were recorded, and δV versus

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Selective effect of procaine, tetracaine and dibucaine on gold nanoparticles

An aqueous colloid dispersion of gold nanoparticles (AuNPs) was prepared by reduction of gold(III) chloride and its interaction with three local anesthetics (procaine, dibucaine or tetracaine) was investigated. Optical spectra reveal the modifications in the absorption band of nanoparticles related to their self assembly mediated by anesthetic molecules and depending on the progress in time of the aggregation process. TEM images show the features

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New procedure to synthesize silver nanoparticles and their interaction with local anesthetics

Silver nanoparticles (AgNPs) were prepared in aqueous colloid dispersions by the reduction of Ag+ with glucose in alkaline medium. Tetraethyl orthosilicate and l-asparagine were added as stabilizers of NPs. The AgNPs were characterized, and their interaction with three local anesthetics (procaine, dibucaine, or tetracaine) was investigated. Optical spectra show the characteristic absorption band of AgNPs, due to surface plasmon resonance. Modifications

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Biogenic syntheses of gold nanoparticles using plant extracts

A biogenic approach for the synthesis of gold nanoparticles (GNPs) by reducing chloroauric acid (HAuCl4) with three different plant extracts (from Angelica, Hypericum, and Hamamelis) is described. The content of reducing compounds (polyphenols) in each plant extract was determined by photometric dosing. The formation of GNPs was tracked by ultraviolet-visible spectroscopy and their characterization was performed using transmission electron microscopy

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