Search results for "Light scattering"
showing 10 items of 464 documents
Growth of a colloidal crystallite of hard spheres
1997
Abstract We examine the growth of a single nucleus of hard spheres in a super-saturated colloidal dispersion of hard spheres. A model developed by Bruce Ackerson and Klaus Schatzel based on a Wilson-Frenkel growth law is used. Our emphasis is on the profile of the radial density distribution around the growing (but still spherically symmetric) grain and its Fourier transform, the grain's form factor, which can be observed under small scattering angles in a dynamic light scattering experiment. Depending on the value of the supersaturation we can identify two limiting cases of different growth exponents and density profiles: one is the Frank theory of diffusion-limited growth and the other is…
Thermal Aggregation of Bovine Serum Albumin in Trehalose and Sucrose Aqueous Solutions
2012
We report results of static and dynamic light scattering measurements performed on bovine serum albumin (BSA) in saccharide (trehalose and sucrose) solutions. Our aim is to study the effects of the two disaccharides on the first steps of thermal aggregation of BSA in aqueous solutions at two protein concentrations (1 and 30 mg/mL) at increasing sugar/water ratio. Results show that sugars modify early stages of aggregation mainly by perturbing the thermodynamic behavior of the solvent (i.e., general solvent effects) without involving direct, specific sugar-protein interactions. This agrees with current hypotheses on sugar action in protein solutions. (1-3) The linear correlation detected bet…
Solidification kinetics of hard-sphere colloidal suspensions
2007
We investigate the solidification dynamics of hard-sphere colloidal suspensions applying simultaneously small-angle and Bragg light scattering. These experiments allow a consistent picture of nucleation and crystal growth on the level of large-scale density fluctuations and of density fluctuations on the level of individual crystallites. We observe a temporally almost constant nucleation rate after an induction time that decreases with supersaturation. The classical expectation for the nucleation rate density as a function of supersaturation is in accordance with our data. We investigate the validity of the Wilson—Frenkel growth law for hard-sphere systems, which also fits our data satisfac…
Theoretical and experimental evaluation of decypolyglucoside vesicles as potential drug delivery systems
2006
The aim of this work was to ascertain the capability of a commercial mixture of decylpolyglucoside (Orami.x NS10) to form vesicle structures in water, either alone or in association with cholesterol. To this purpose, we compared results obtained from a theoretical model with those acquired from the experimental characterization of different Orami.x NS10/cliolesterol mixtures. The germen vesicular formation theory was used to predict the formation process of vesicular structures. To this purpose, the energy balance involved in the vesicle formation was calculated using critical concentration for vesicle formation (ccf), surface tension and molecular area of decylpolyglucoside. The ccf was me…
POSS-tetraalkylammonium salts: A new class of ionic liquids
2012
A series of new polyhedral oligomeric silsesquioxane ionic liquids (POSS-ILs) based on the trimethylpropylammonium dielectric constants, which, conversely, display slight differences originating from the nature of the anions. The long alkyl-chain substituents on the POSS core infer on this series of ILs an overall hydrophobic character and solution properties comparable to those of classic cationic surfactants, resulting in an effective extractant capability of polyanions from aqueous solutions. Their solution diffusion properties, as investigated by room-temperature dynamic light scattering, solution conductivity, density, and osmometric measurements, do not provide evidence for the occurr…
Development and characterization of co-loaded curcumin/triazole-halloysite systems and evaluation of their potential anticancer activity.
2014
Abstract Positively charged halloysite nanotubes functionalized with triazolium salts (f-HNT) were employed as a carrier for curcumin molecules delivery. The synthesis of these f-HNT new materials is described. Their interaction with curcumin was evaluated by means dynamic light scattering (DLS) and UV–vis spectroscopy in comparison with pristine unmodified HNT (p-HNT). The curcumin load into HNT was estimated by thermogravimetric analysis (TGA) measurements, while the morphology was investigated by scanning electron microscopy (SEM) techniques. Release of curcumin from f-HNT, at three different pH values, by means of UV–vis spectroscopy was also studied. Furthermore, different cancer cell …
Elaboration of Trans-Resveratrol Derivative-Loaded Superparamagnetic Iron Oxide Nanoparticles for Glioma Treatment
2019
In this work, new nanohybrids based on superparamagnetic iron oxide nanoparticles (SPIONs) were elaborated and discussed for the first time as nanovectors of a derivative molecule of trans-resveratrol (RSV), a natural antioxidant molecule, which can be useful for brain disease treatment. The derivative molecule was chemically synthesized (4&rsquo
Ecocompatible Halloysite/Cucurbit[8]uril Hybrid as Efficient Nanosponge for Pollutants Removal
2016
Hybrid materials based on halloysite nanotubes (HNT) and cucurbit[8]uril (CB[8]) were prepared with the aim to obtain efficient nanosponges towards hydrocarbons both in liquid and vapor phases. The loading on both HNT surfaces and the hybrid morphology were evidenced by FTIR spectroscopy, thermogravimetric analysis and scanning electron microscopy. In order to highlight the interactions in the hybrid 13C {1H} CP-MAS NMR experiments were performed. The aqueous colloidal stability of HNT/CB[8] was highlighted through ζ potential and dynamic light scattering measurements. The HNT/CB[8] composite was employed as nanosponge to capture aromatic oils in aqueous phase as evidenced by fluorescence e…
Effect of uniaxial deformation on the optical scattering losses of a semicrystalline fluorocopolymer.
1997
Both small- and wide-angle light scattering as well as transmission measurements have been used to investigate the optical scattering losses of a vinylidene difluoride–tetrafluoroethylene–hexafluoropropylene copolymer crystallized from the melt. The main origin of the scattering loss is the wide-angle light scattering from the spherulitic superstructure. Uniaxial deformation transforms this structure into a fiber morphology. The attenuation of fibers has been measured for light propagating both parallel and perpendicular to the orientation axis. For both directions, the attenuation decreases with increasing draw ratio. Annealing of the fibers while keeping their ends fixed is an effective m…
Effect of Light Scattering Simulation in the Eye on Different Color Stimuli Perception
2008
One of the factors which influences visual functions is intraocular light scattering. To assess the effect of light scattering and stimulus color on visual functions, visual acuity and retinal straylight were measured with and without light scattering occluder. For visual acuity measurements black Landolt optotypes on red, green and blue background were used. Retinal straylight was measured with a direct compensation method using the same colors stimuli. For one subject straylight was measured with 5 different light scattering levels of eye occluder.