Search results for "colloids"

A combined molecular dynamics and Monte Carlo study of the approach towards phase separation in colloid-polymer mixtures.

2011

A coarse-grained model for colloid-polymer mixtures is investigated where both colloids and polymer coils are represented as point-like particles interacting with spherically symmetric effective potentials. Colloid-colloid and colloid-polymer interactions are described by Weeks-Chandler-Andersen potentials, while the polymer-polymer interaction is very soft, of strength k(B)T/2 for maximum polymer-polymer overlap. This model can be efficiently simulated both by Monte Carlo and molecular dynamics methods, and its phase diagram closely resembles that of the well-known Asakura-Oosawa model. The static and dynamic properties of the model are presented for systems at critical colloid density, va…

Zr, Hf and REE fractionation between dissolved pool and sediments in river waters. Effect of changing ionic strength conditions in element partitioni…

Zr, Hf and REE distribution in river water under different ionic strength conditions

2018

International audience; The Platani River flowing in south-central Sicily, interacting with evaporite rocks, generates a wide range of ionic strength in the water catchment from 0.1 to 5.0 mol kg−1. We sampled 38 river sites and analysed the composition for the dissolved fraction filtered through 0.45 μm, the truly dissolved fraction obtained through ultrafiltration (10 kDa) and the relative included colloidal fraction.This study was focused on the recognition of Zr, Hf and REE behaviour under changing ionic strength conditions, since this is one of parameters responsible for colloid stability in natural waters. In turn, this phenomenon leads to REE release from the colloidal fraction and t…

The role of mucilage of Opuntia ficus-indica Mill. on sweet cherry fruit during storage

2022

Sweet cherry (Prunus avium L.) is an important crop from temperate areas and is widespread and much appreciated by the consumers when the pedicel is green. The objective of this work was to evaluate the quality of sweet cherry fruit treated with a mucilage coating, extracted from cladodes of Opuntia ficus-indica L. Mill (OFI). The cultivar ‘Ferrovia’ was harvested at the commercial ripeness stage from an orchard in Puglia (Italy), stored for 14 days at 2°C and RH 92% and to evaluated by the variation of color and other qualitative parameters such as physical-chemical, nutraceutical and sensory analysis. Fruits were transferred at 10°C to postharvest laboratory of University of Palermo after…

Qualitative traits and shelf life of fig fruit (cv Melanzana) treated with Aloe vera gel coating

2021

The fig (Ficus carica L.) cv Melanzana is typical of Southern Italy. This cultivar produces breba fruit in June and fig fruit in August. Some previous studies on the use of coatings extracted from stems of Aloe vera showed positive effects to maintain fruit quality during shelf life. However, there are no studies on breba fig fruit treated with Aloe vera coating. In this study breba fig fruit, cv Melanzana, was treated with an application of Aloe vera gel, sealed in macro-perforated bag and stored at 5°C for 10 days. The effect of application of the Aloe vera gel on the shelf-life of this fruit, and its quality attributes after application were evaluated measuring fresh weight, total solubl…

Albumin-driven disassembly of lipidic nanoparticles: the specific case of the squalene-adenosine nanodrug

2020

International audience; In the field of nanomedicine, nanostructured nanoparticles (NPs) made of self-assembling prodrugs emerged in the recent years with promising properties. In particular, squalene-based drug nanoparticles have already shown their efficiency through in vivo experiments. However, a complete pattern of their stability and interactions in the blood stream is still lacking. In this work we assess the behavior of squalene-adenosine (SQAd) nanoparticles-whose neuroprotective effect has already been demonstrated in murine models-in the presence of fetal bovine serum (FBS) and of bovine serum albumin (BSA), the main protein of blood plasma. Extensive physicochemical characteriza…

Surface Characteristics Control the Attachment and Functionality of (Chimeric) Avidin

2018

The physical adsorption (physisorption) of proteins to surfaces is an important but incompletely understood factor in many biological processes and is of increasing significance in bionanotechnology as well. Avidin is an important protein because of strong avidin–biotin binding, which has been exploited in numerous applications. We have undertaken thorough experimentation on the physisorption of avidin, to chemically different flat surfaces of Si and graphite and also to the curved version of the latter, on multiwalled carbon nanotubes (MWNTs) of different diameters. The difference in the behavior of avidin on Si versus graphite is drastic; on Si, avidin deposits as single globular tetramer…

Experimental and theoretical evidence of overcharging of calcium silicate hydrate

2007

International audience; Electrokinetic measurements such as electrophoresis may show an inversion of the effective surface charge of colloidal particle called overcharging. This phenomenon has been studied by various theoretical approaches but up to now very few attempts of confrontation between theory and experiment have been conducted. In this work we report electrophoretic measurements as well as Monte Carlo simulations of the electrokinetic potential for the surface of calcium silicate hydrate (Csingle bondSsingle bondH), which is the major constituent of hydrated cement. In the simulations, the surface charge of Csingle bondSsingle bondH nanoparticles in equilibrium with the ionic solu…

Alteration of anion gap during almost total plasma replacement with synthetic colloids in piglets

2000

In ten piglets (body weight 8.2-11.6 kg), acid base, electrolyte and anion gap changes were investigated during almost total plasma replacement with hydroxyethyl starch (HES) and modified fluid gelatin (GEL) in saline solution using a cell saver autotransfusion technique. During the study, there were only moderate acid base changes, but marked disturbances in anion balance. At study end, the mean chloride concentration was significantly higher (mmol/l: normal values 97-108, HES 116 +/- 1.5, GEL 108 +/- 1.1, p0.01) and the mean anion gap was significantly lower in the HES group in comparison to the GEL group (mmol/l: normal values 5-14, HES 3 +/- 1.7, GEL 11.9 +/- 0.9, p0.01). It is conclude…

Versailles project on advanced materials and standards (VAMAS) interlaboratory study on measuring the number concentration of colloidal gold nanopart…

2022

The advancement of analytical methods for nanoparticle measurements is critical both for the growing industrial exploitation of engineered nanoparticles and for developing robust strategies to understand and control the concentration of nanomaterials in humans and the environment. For high value nanoparticles, the measurement of nanoparticle number concentration in a liquid directly impacts the ability to assess the scale and reproducibility of the production process, it allows optimisation of efficiency and supports regulatory compliance. This measurement is also useful to monitor and control the intentional or accidental release of engineered nanoparticles into the environment at the produc…