Characterization of superparamagnetic iron oxide coated with silicone used as contras agent for magnetic resonance image for the gastrointestinal tract - Gamarra, Lionel Fernel; Mamani, J. B; Carneiro, S M; Fabris, J D; Ferreira, R. V; Domingues, R. Z; Cornejo, Daniel Reinaldo; Pontuschka, Walter Maigon; Amaro Junior, Edson (Journal of nanoscience and nanotechnology, 2010)