Luis Carlos Duarte Cavalcante

Thermosensitive gemcitabine-magnetoliposomes for combined hyperthermia and chemotherapy.

The combination of magnetic hyperthermia therapy with the controlled release of chemotherapeutic agents in tumors may be an efficient therapeutic with few side effects because the bioavailability, tolerance and amount of the drug can be optimized. Here, we prepared magnetoliposomes consisting of magnetite nanoparticle cores and the anticancer drug gemcitabine encapsulated by a phospholipid bilayer. The potential of these magnetoliposomes for controlled drug release and cancer treatment via hyperthermic behavior was investigated. The magnetic nanoparticle encapsulation efficiency was dependent on the initial amount of magnetite nanoparticles present at the encapsulation stage; the best formulation was 66%. We chose this formulation to characterize the physicochemical properties of the magnetoliposomes and to encapsulate gemcitabine. The mean particle size and distribution were determined by dynamic light scattering (DLS), and the zeta potential was measured. The magnetoliposome formulations all had acceptable characteristics for systemic administration, with a mean size of approximately 150 nm and a polydispersity index <0.2. The magnetoliposomes were stable in aqueous suspension for at least one week, as determined by DLS. Temperature increases due to the dissipation energy of magnetoliposome suspensions subjected to an applied alternating magnetic field (AMF) were measured at different magnetic field intensities, and the values were appropriated for cancer treatments. The drug release profile at 37 °C showed that 17% of the gemcitabine was released after 72 h. Drug release from magnetoliposomes exposed to an AMF for 5 min reached 70%.

Pedra Do Sino: Primeiro Registro De Um Sítio De Arte Rupestre Em Caldeirão Grande Do Piauí / Pedra Do Sino: First Record Of a Rock Art Site In Caldeirão Grande Do Piauí

Este trabalho apresenta o primeiro registro de um sitio de arte rupestre no municipio de Caldeirao Grande do Piaui, Nordeste do Brasil. O sitio arqueologico conhecido como Pedra do Sino e um bloco de granito, contendo vestigios de pinturas rupestres em diferentes tons de vermelho. Os motivos pintados representam grafismos de tendencia geometrica e alguns vestigios sem forma definida. Liticos lascados foram encontrados em superficie, no entorno do bloco rochoso. Os principais problemas de conservacao foram documentados e discutidos em detalhe. Como consequenciada busca de tesouros, uma crenca ainda corrente entre os municipes, os sedimentos pre-historicos foram escavados sem criterios, perdendo-se assim o contexto arqueologico na parte frontal do sitio, onde se concentra a maioria das pinturas. Palavras-chave : Sitio Arqueologico. Pinturas Rupestres. Mito Do Tesouro. Patrimonio Arqueologico. ABSTRACT This work presents the first record of a rock art site in the municipality from Caldeirao Grande do Piaui, Northeast of Brazil. The archaeological site known as Pedra do Sino is a granite block containing vestiges of rock paintings in different reddish hues. The motifs painted represent geometricgraphisms, but also occur vestiges of figures with shapes undefined. Chipped lithics were found in the surface of the soil in around of the rock block. The main conservation problems were documented and discussed in detail.In search of treasures, the prehistoric sediments were excavated without criteria and the archaeological context was lost. Keywords : Archaeological Site. Rockpaintings. Myth Of Treasure. Archaeological Heritage.