Search results for "Particle"
showing 10 items of 15225 documents
A Nanoparticulate Drug-Delivery System for Rivastigmine: Physico-Chemical and in vitro Biological Characterization
2007
The preparation and characterization of surface-PEGylated polymeric nanoparticles are described. These systems were obtained by UV irradiation of PHM and PHM-PEG 2000 as an inverse microemulsion, using an aqueous solution of the PHM/PHM-PEG 2000 copolymer mixture as the internal phase and triacetin saturated with water as the external phase, and characterized by dimensional analysis, zeta-potential measurements and XPS. in vitro biological tests demonstrated their cell compatibility and their ability to escape from phagocytosis. Rivastigmine was encapsulated into the nanoparticle structure and drug-release profiles from loaded samples were investigated in PBS at pH = 7.4 and human plasma.
Thermal and Chemical Stability of Thiol Bonding on Gold Nanostars
2015
The stability of thiol bonding on the surface of star-shaped gold nanoparticles was studied as a function of temperature in water and in a set of biologically relevant conditions. The stability was evaluated by monitoring the release of a model fluorescent dye, Bodipy-thiol (BDP-SH), from gold nanostars (GNSs) cocoated with poly(ethylene glycol) thiol (PEG-SH). The increase in the BDP-SH fluorescence emission, quenched when bound to the GNSs, was exploited to this purpose. A maximum 15% dye release in aqueous solution was found when the bulk temperature of gold nanostars solutions was increased to T = 42 °C, the maximum physiological temperature. This fraction reduces 3-5% for temperatures …
Chromogenic Chemodosimeter Based on Capped Silica Particles to Detect Spermine and Spermidine
2021
A new hybrid organic–inorganic material for sensing spermine (Spm) and spermidine (Spd) has been prepared and characterized. The material is based on MCM-41 particles functionalized with an N-hydroxysuccinimide derivative and loaded with Rhodamine 6G. The cargo is kept inside the porous material due to the formation of a double layer of organic matter. The inner layer is covalently bound to the silica particles, while the external layer is formed through hydrogen and hydrophobic interactions. The limits of detection determined by fluorimetric titration are 27 µM and 45 µM for Spm and Spd, respectively. The sensor remains silent in the presence of other biologically important amines and is a…
Application of Modified Tafel Analysis to the Identification of Corrosion Products on Archaeological Metals Using Voltammetry of Microparticles
2011
Voltammetry of microparticles is applied to the identification of lead corrosion products by means of an essentially non-invasive 'one-touch' technique based on the use of graphite pencil. This methodology permits the mechanical attachment of few nanograms of sample from the surface of lead archaeological artefacts to a paraffin-impregnated graphite electrode, which, upon immersion in aqueous electrolytes, provides distinctive voltammetric responses for litharge and cotunnite- anglesite-, cerusite-based corrosion products. The reported method is applied to the identification of corrosion products in archaeological lead pieces from different Iberian sites in Valencia (Spain). © 2011 WILEY-VC…
Electrochemical Fingerprint of Archeological Lead Silicate Glasses Using the Voltammetry of Microparticles Approach
2016
9 págs.; 14 figs.; 1 tab.
Consolidation and protection by nanolime: recent advances for the conservation of the graffiti, Carceri dello Steri Palermo and of the 18th century l…
2014
Abstract Nanolime dispersed in 2-propanol was extensively used for the consolidation of wall paintings. The knowledge of the advances of this methodology dealing with all the possible effects associated with the nanolime new material in conservation is fundamental to assess and improve the technique. In this paper, four different dispersions of Ca(OH) 2 nanoparticles were characterised by Small Angle X-rays Scattering technique (SAXS) and Transmission Electron Microscopy (TEM) in order to achieve information on size, shape, polydispersity, agglomeration, and crystal structure (by SAED patterns) of the particles. Once characterised, the dispersions were tested in two different case studies, …
Measurements of aerosol and CCN properties in the Mackenzie River delta (Canadian Arctic) during spring–summer transition in May 2014
2018
Within the framework of the RACEPAC (Radiation–Aerosol–Cloud Experiment in the Arctic Circle) project, the Arctic aerosol, arriving at a ground-based station in Tuktoyaktuk (Mackenzie River delta area, Canada), was characterized during a period of 3 weeks in May 2014. Basic meteorological parameters and particle number size distributions (PNSDs) were observed and two distinct types of air masses were found. One type were typical Arctic haze air masses, termed accumulation-type air masses, characterized by a monomodal PNSD with a pronounced accumulation mode at sizes above 100 nm. These air masses were observed during a period when back trajectories indicate an air mass origin in the north-e…
Fluorogenic detection of Tetryl and TNT explosives using nanoscopic-capped mesoporous hybrid materials
2013
[EN] A hybrid capped mesoporous material, which was selectively opened in the presence of Tetryl and TNT, has been synthesised and used for the fluorogenic recognition of these nitroaromatic explosives.
Isolation and characterization of a complement-activating lipid extracted from human atherosclerotic lesions.
1990
The major characteristics of human atherosclerotic lesions are similar to those of a chronic inflammatory reaction, namely fibrosis, mesenchymal cell proliferation, the presence of resident macrophages, and cell necrosis. Atherosclerosis exhibits in addition the feature of lipid (mainly cholesterol) accumulation. The results of the present report demonstrate that a specific cholesterol-containing lipid particle present in human atherosclerotic lesions activates the complement system to completion. Thus, lipid could represent a stimulatory factor for the inflammatory reaction, whose underlying mechanistic basis may be, at least in part, complement activation. The complement-activating lipid …
Finite-Time Control for Attitude Tracking Maneuver of Rigid Satellite
2014
Published version of an article in the journal: Abstract and Applied Analysis. Also available from the publisher at: http://dx.doi.org/10.1155/2014/302982 Open Access The problem of finite-time control for attitude tracking maneuver of a rigid spacecraft is investigated. External disturbance, unknown inertia parameters are addressed. As stepping stone, a sliding mode controller is designed. It requires the upper bound of the lumped uncertainty including disturbance and inertia matrix. However, this upper bound may not be easily obtained. Therefore, an adaptive sliding mode control law is then proposed to release that drawback. Adaptive technique is applied to estimate that bound. It is prov…