Multiple emulsions for simultaneous active agents delivery in a skin topical application

Most antiseptic agents are intended for use on intact skin, e.g. for hand hygiene or skin preparation before any medical procedure. This paper presents multiple emulsion-based antiseptic agents as formulations for application to body surfaces with modified release rates. Multiple emulsions with a co-encapsulated antiseptic (phenyl salicylate – salol) and an agent preventing microorganism growth (benzoic acid) were formed in a Couette–Taylor flow apparatus. Results confirmed the possibility of the release kinetics modification while two compounds were encapsulated in the internal droplets of emulsions to control the release rates and time of the dose release. The addition of benzoic acid as a second active compound of the encapsulation process in the internal phase of double O1/W/O2 emulsion reduced the time necessary for the total release of salol triggering a two-step release

Characterization of alumina- and niobia-supported gold catalysts used for oxidation of glycerol

Gold catalysts supported on niobia and alumina are active in glycerol oxidation performed in liquid basic solution in the presence of oxygen. Niobia-supported gold is only slightly less active than commercial Au/TiO2 catalyst. XPS data allow to characterize gold nanoparticles on both supports. IR studies show that CO adsorbs on gold particles loaded on niobia producing well characterized terminal carbonyls whose C-O stretching frequency shifts up by decreasing CO coverage, an usual behaviour for gold carbonyls. Two families of gold nanoparticles on niobia are characterized by CO stretching frequencies of adsorbed CO at 2098-2112 cm(-1) after reduction at 573 K and at 2108-2120 and 2125-2135 cm(-1) after reduction at 773 K. However, after both reduction pretreatments such gold metal particles coexist with strongly oxidizing gold species which are able to convert CO into CO2 at 153-193K. Based on IR and XPS experiments, the lower activity of alumina-supported gold may be due to a lower density of corner and edge sites on Au nanoparticles, associated to the minor dispersing ability of alumina for gold. (C) 2010 Elsevier B.V. All rights reserved

Influence of nanocrystalline structure and surface properties of TiO2 thin films on the viability of L929 cells

In this work the physicochemical and biological properties of nanocrystalline TiO2 thin films were investigated. Thin films were prepared by magnetron sputtering method. Their properties were examined by X-ray diffraction, photoelectron spectroscopy, atomic force microscopy, optical transmission method and optical profiler. Moreover, surface wettability and scratch resistance were determined. It was found that as-deposited coatings were nanocrystalline and had TiO2-anatase structure, built from crystallites in size of 24 nm. The surface of the films was homogenous, composed of closely packed grains and hydrophilic. Due to nanocrystalline structure thin films exhibited good scratch resistance. The results were correlated to the biological activity (in vitro) of thin films. Morphological changes of mouse fibroblasts (L929 cell line) after contact with the surface of TiO2 films were evaluated with the use of a contrast-phase microscope, while their viability was tested by MTT colorimetric assay. The viability of cell line upon contact with the surface of nanocrystalline TiO2 film was comparable to the control sample. L929 cells had homogenous cytoplasm and were forming a confluent monofilm, while lysis and inhibition of cell growth was not observed. Moreover, the viability in contact with surface of examined films was high. This confirms non-cytotoxic effect of TiO2 film surface on mouse fibroblasts

Artificial Neural Networks To Distinguish Charcoal from Eucalyptus and Native Forests Based on Their Mineral Components

International audienceCharcoal is produced through the pyrolysis of wood. It is used as the main domestic energy source in many tropical countries from Africa and Asia, and it is used as a reductor product in the steel industry in Brazil. However, the indiscriminant use of wood from native forests is detrimental to sustainability. The development of rapid and efficient methodologies for distinguishing charcoal produced from native forest or Eucalyptus plantations, as found partially in Brazil, is essential to curb illegal charcoal transport and trade. The aim of this study was to distinguish charcoals from native or Eucalyptus woods by using artificial neural networks (ANNs) based on their mineral composition. Specimens from Brazilian native woods (Apuleia sp., Cedrela sp., Aspidosperma sp., Jacaranda sp., Peltogyne sp., Dipteryx sp., and Gochnatia sp.) and from Eucalyptus sp. hybrid woods of commercial forest plantations were pyrolyzed at temperatures from 300 °C to 700 °C in order to simulate the actual pyrolysis conditions and species widely used illegally in southeastern Brazil. Charcoals composition and proportion of mineral elements were determined by X-ray fluorescence. The ANNs were trained based on the elemental composition of the charcoal specimens to classify the species and origin of the charcoals (i.e., native forest or Eucalyptus). The ANNs based on mineral element content yielded high percentage of correct classification for charcoal specimens by species (72% accuracy) or origin (97% accuracy) from an independent validation sample set

Influence of nanocrystalline structure and surface properties of TiO2 thin films on the viability of L929 cells

In this work the physicochemical and biological properties of nanocrystalline TiO2 thin films were investigated. Thin films were prepared by magnetron sputtering method. Their properties were examined by X-ray diffraction, photoelectron spectroscopy, atomic force microscopy, optical transmission method and optical profiler. Moreover, surface wettability and scratch resistance were determined. It was found that as-deposited coatings were nanocrystalline and had TiO2-anatase structure, built from crystallites in size of 24 nm. The surface of the films was homogenous, composed of closely packed grains and hydrophilic. Due to nanocrystalline structure thin films exhibited good scratch resistance. The results were correlated to the biological activity (in vitro) of thin films. Morphological changes of mouse fibroblasts (L929 cell line) after contact with the surface of TiO2 films were evaluated with the use of a contrast-phase microscope, while their viability was tested by MTT colorimetric assay. The viability of cell line upon contact with the surface of nanocrystalline TiO2 film was comparable to the control sample. L929 cells had homogenous cytoplasm and were forming a confluent monofilm, while lysis and inhibition of cell growth was not observed. Moreover, the viability in contact with surface of examined films was high. This confirms non-cytotoxic effect of TiO2 film surface on mouse fibroblasts