Search results for "Small Angle"
showing 10 items of 47 documents
Fabrication of quercetin and curcumin bionanovesicles for the prevention and rapid regeneration of full-thickness skin defects on mice
2013
In the present work biocompatible quercetin and curcumin nanovesicles were developed as a novel approach to prevent and restore skin tissue defects on chronic cutaneous pathologies. Stable and suitable quercetin- and curcumin-loaded phospholipid vesicles, namely liposomes and penetration enhancer-containing vesicles (PEVs), were prepared. Vesicles were made from a highly biocompatible mixture of phospholipids and alternatively a natural polyphenol, quercetin or curcumin. Liposomes were obtained by adding water, while PEVs by adding polyethylene glycol 400 and Oramix®CG110 to the water phase. Transmission electron microscopy, cryogenic-transmission electron microscopy and small- and wide-ang…
Treatment of grazing-incidence small-angle X-ray scattering data taken above the critical angle
2001
The equations taking into account refraction at the sample surface in grazing-incidence small-angle X-ray scattering (GISAXS) when the angle between the incoming beam and the sample surface is slightly larger than the critical angle are derived and discussed. It is demonstrated that the refraction of both the incoming and the scattered beam at the sample surface affects the GISAXS pattern and that, when a planar bidimensional detector perpendicular to the incoming beam is used, the effect depends on the azimuthal detector angle. The smearing of the pattern depending on the size of the illuminated sample area in grazing incidence is estimated by simulations with Cauchy functions of different…
Interaction mechanism of endogenous PP2A inhibitor protein ENSA with PP2A
2022
The vast diversity of protein phosphatase 2A (PP2A) holoenzyme composition ensures its multifaceted role in the regulation of cellular growth and signal transduction. In several pathological conditions, such as cancer, PP2A is inhibited by endogenous inhibitor proteins. Several PP2A inhibitor proteins have been identified, one of which is α-endosulfine (ENSA). ENSA inhibits PP2A activity when it is phosphorylated at Ser67 by Greatwall (Gwl) kinase. The role of ENSA in PP2A inhibition is rather well characterized, but knowledge of the mechanism of inhibition is scarce. In this study, we have performed comprehensive structural characterization of ENSA, and its interaction with PP2A A- and var…
The Pyridyl Functional Groups Guide the Formation of Pd Nanoparticles Inside A Porous Poly(4-Vinyl-Pyridine)
2015
The reactivity of palladium acetate inside a poly(4-vinylpyridine-co-divinylbenzene) polymer is strongly influenced by the establishment of interaction between the Pd precursor and the pyridyl functional group in the polymer. Diffuse reflectance infrared Fourier transform spectroscopy (DRIFTS) and simultaneous X-ray absorption near edge structure (XANES) and small angle X-ray scattering (SAXS) techniques have been applied to monitor the reactivity of palladium acetate in the presence of H-2 and CO as a function of temperature. H-2 reduces palladium acetate to Pd nanoparticles and acetic acid. The pyridyl groups in the polymer play a vital role both in stabilizing the formed acetic acid, thu…
The Largest Synthetic Structure with Molecular Precision: Towards a Molecular Object
2010
Pushing the limits: A 200A - 10 Da structurally defined, linear macromolecule (PG5) has a molar mass, cross-section dimension, and cylindrical shape that are comparable to some naturally occurring objects, such as amyloid fibrils or certain plant viruses. The macromolecule is resistant against flattening out on a surface; the picture shows PG5 embracing the tobacco mosaic virus (TMV).
Nutriosomes: Prebiotic delivery systems combining phospholipids, a soluble dextrin and curcumin to counteract intestinal oxidative stress and inflamm…
2018
Nutriosomes, new phospholipid nanovesicles specifically designed for intestinal protection were developed by simultaneously loading a water-soluble dextrin (Nutriose® FM06) and a natural antioxidant (curcumin). Nutriosomes were easily fabricated in a one-step, organic solvent-free procedure. The stability and delivery performances of the vesicles were improved by adding hydroxypropyl methylcellulose. All the vesicles were small in size (mean diameter ∼168 nm), negatively charged (zeta potential ∼-38 mV, irrespective of their composition), and self-assembled predominantly in unilamellar vesicles stabilized by the presence of Nutriose®, which was located in both the inter-lamellar and inter-v…
Proteins in amorphous saccharide matrices: Structural and dynamical insights on bioprotection
2013
Bioprotection by sugars, and in particular trehalose peculiarity, is a relevant topic due to the implications in several fields. The underlying mechanisms are not yet clearly elucidated, and remain the focus of current investigations. Here we revisit data obtained at our lab on binary sugar/water and ternary protein/sugar/water systems, in wide ranges of water content and temperature, in the light of the current literature. The data here discussed come from complementary techniques (Infrared Spectroscopy, Molecular Dynamics simulations, Small Angle X-ray Scattering and Calorimetry), which provided a consistent description of the bioprotection by sugars from the atomistic to the macroscopic …
Formation and Growth of Pd Nanoparticles Inside a Highly Cross-Linked Polystyrene Support: Role of the Reducing Agent
2014
Simultaneous time-resolved SAXS and XANES techniques were employed to follow in situ the formation of Pd nanoparticles in a porous polystyrene support, using palladium acetate as a precursor and gaseous H2 or CO as reducing agents. These results, in conjunction with data obtained by diffuse reflectance UV–vis and DRIFT spectroscopy and TEM measurements, allowed unraveling of the different roles played by gaseous H2 and CO in the formation of the Pd nanoparticles. In particular, it was found that the reducing agent affects (i) the reduction rate (which is faster in the presence of CO) and (ii) the properties of the hosted nanoparticles, in terms of size (bigger with CO), morphology (spherica…
Flash microwave synthesis of trevorite nanoparticles.
2008
Nickel ferrite nanoparticles have several possible applications as cathode materials for rechargeable batteries, named 'lithium-ion' batteries. In this study, NiFe{sub 2}O{sub 4} was prepared by microwave induced thermohydrolysis. The obtained nanoparticles were characterized by scanning electron microscopy (SEM) and energy dispersive X-ray spectroscopy (EDX), X-ray diffraction (XRD), BET method, transmission electron microscopy (TEM) and small angle X-ray scattering (SAXS). All the results show that the microwave one-step flash synthesis leads in a very short time to NiFe{sub 2}O{sub 4} nanoparticles with elementary particles size close to 4-5 nm, and high specific surfaces (close to 240 m…
Quaternary structures of GroEL and naïve-Hsp60 chaperonins in solution: a combined SAXS-MD study
2015
The quaternary structures of bacterial GroEL and human naïve-Hsp60 chaperonins in physiological conditions have been investigated by an innovative approach based on a combination of synchrotron Small Angle X-ray Scattering (SAXS) in-solution experiments and molecular dynamics (MD) simulations. Low-resolution SAXS experiments over large and highly symmetric oligomers are analyzed on the basis of the high-resolution structure of the asymmetric protein monomers, provided by MD. The results reveal remarkable differences between the solution and the crystallographic structure of GroEL and between the solution structures of GroEL and of its human homologue Hsp60.