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ABSTRACT:The article is concerned with the preparation of polymer-iron oxide nanocomposites and the study as drug-delivery matrices under the influence of applied magnetic field. Biocompatible materials were prepared by incorporating an aqueous ferrofluid in poly(vinyl alcohol) and scleroglucan (SCL) hydrogels, loaded with theophylline as model drug for release studies. The in vitro release profile was obtained using a flat Franz cell and the kinetic parameters were derived applying a semiempirical power law. A magnetic characterization of nanoparticles contained in the ferrofluid was performed by obtaining the magnetization curve. For both systems, the observed drug release profiles decreased when a uniform external magnetic field is applied suggesting they can be used as environmental responsive matrices for biomedical applications. Dynamic rheological measurements show that a higher storage modulus and a more compact structure are obtained by incorporating the ferrofluid into the hydrogels. These rheological results and environmental electron scanning microscopy micrographs point to an understanding of release behavior once the magnetic field is applied.

The thermocatalytic cracking (TCC) process, which can selectively produce light olefins (mostly, ethylene and propylene for the petrochemical industry) and transportation fuels (gasoline and diesel fuel), combines the effects of thermal and catalytic cracking reactions. The TCC catalysts consist mainly of mixed metal oxides supported on a high-surface area -thermally stabilized alumina. The best TCC catalyst formulation includes a co-catalyst, which provides the main catalyst component with active hydrogen species formed from hydrogen and other hydrocarbons, particularly methane, produced mainly by thermal cracking. The interparticular interactions of these hydrogen spilt-over species can occur because these species can be easily transferred from one particle to the other through the newly formed pore connections

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