Preparation and characterization of chloroaluminum phthalocyanine-loaded solid lipid nanoparticles by thermal analysis and powder X-ray diffraction techniques

Solid lipid nanoparticles (SLN) without drug and SLN loaded with chloroaluminum phthalocyanine (AlClPc) were prepared by solvent diffusion method in aqueous system and characterized by thermal analyses and X-ray diffraction (XRD) in this study. Determination of particle size, zeta potential (ZP), and encapsulation efficiency were also evaluated. SLN containing AlClPc of nanometer size with high encapsulation efficiency and ZP were obtained. The results indicated that the size of SLN loaded with AlClPc is larger than that of the inert particle, but ZP is not changed significantly with incorporation of the drug. In differential scanning calorimetry (DSC) curves, it was observed that the melting point of stearic acid (SA) isolated and in SLN occurred at 55 and 64 degrees C, respectively, suggesting the presence of different polymorphs. DSC also shows that the crystallinity state of SLN was much less than that of SA isolated. The incorporation of drug in SLN may have been favored by this lower crystallinity degree of the samples. XRD techniques corroborated with the thermal analytic techniques, suggesting the polymorphic modifications of stearic acid.Conselho Nacional de Desenvolvimento Cientifico e Tecnologico (CNPq), BrazilFundacao de Amparo a Pesquisa do Estado de Sergipe-FAPITEC/SEMinisterio da SaudeSE

Food Control

Texto completo: Acesso restrito. p. 26 - 213The aim of this study was to evaluate the level of knowledge, attitudes and practices in food safety and the presence of coagulase-positive staphylococci species on the hands of food handlers in the municipal schools of Camaçari, Bahia in northeast Brazil. This study was conducted in two stages. In the first stage, 166 food handlers were interviewed via a questionnaire to assess their food safety knowledge, attitudes and practices. In the second phase, the presence of coagulase-positive staphylococci species on the hands of food handlers was determined. The results indicated that most of the handlers had been trained (92.2%), but the level of knowledge was insufficient; the average proficiency score was <70% accuracy. Attitude received the highest scores, and no handler had a score below 50.0%. Logistic regression analysis showed that the level of education and specific subject expertise of the handlers were associated with general knowledge about food safety. Food handler overall had positive attitudes on food safety with all scores above 50.0%. Despite a high prevalence of training and positive attitudes about food safety, 53.3% of the hand samples showed the presence of coagulase-positive staphylococci. No associations were found between the knowledge attitudes and practices of food handlers and the presence of the pathogen on their hands. The results showed inadequate sanitary practices of food handlers, highlighting the need to review the current model for training food handlers and to improve accessibility to sinks and supplies to ensure proper hygiene.Salvado

Preparation and characterization of erbium and ytterbium co-doped sol-gel SiO2 : HfO2 films for planar waveguides

This work reports on the preparation of erbium and ytterbium co-doped SiO2:HfO2 single mode planar waveguides using the sol-gel method. Silica nanoparticles were prepared from tetraethylorthosilicate in basic media and the films were characterized by transmission electron microscopy, scanning electron microscopy, mechanical profilometry, M-lines spectroscopy based on prism coupling technique, X-ray diffractometry, infrared spectroscopy and photoluminescence spectroscopy. The film thicknesses and the refractive indexes were adjusted in order to satisfy a future efficient coupling to single mode optical fiber. Films suitable for both weak and strong light confinement were prepared varying hafnia concentration into the silica matrix. The lifetime values of erbium I-4(13/2) state were measured in order to investigate the influence of clustering and hydroxyl groups on the fluorescence quantum efficiency of the I-4(13/2) level, responsible for the emission at 1.55 mu m attributed to the I-4(13/2) -> I-4(15/2) transition. The high lifetime values suggest the absence of erbium clusters and the elimination of hydroxyl groups by rapid thermal process. (c) 2007 Elsevier B.V. All rights reserved