Rui Igreja

Cancer is one of the main causes of death in the world and its incidence increases every day. Current treatments are insufficient and present many breaches. Hyperthermia is an old concept and since early it was established as a cancer treatment option, mainly in superficial cancers. More recently the concept of intracellular hyperthermia emerged wherein magnetic particles are concentrated at the tumor site and remotely heated using an applied magnetic field to achieve hyperthermic temperatures (42-45 degrees C). Many patents have been registered in this area since the year 2000. This review presents the most relevant information, organizing them according to the hyperthermic method used: 1) external RadioFrequency devices; 2) hyperthermic perfusion; 3) frequency enhancers; 4) apply heating to the target site using a catheter; 5) injection of magnetic and ferroelectric particles; 6) injection of magnetic nanoparticles that may carry a pharmacological active drug. The use of magnetic nanoparticles is a very promising treatment approach since it may be used for diagnostic and treatment. An ideal magnetic nanoparticle would be able to detect and diagnose the tumor, carry a pharmacological active drug to be delivered in the tumor site, apply hyperthermia through an external magnetic field and allow treatment monitoring by magnetic resonance imaging.

A successful procedure for the in situ synthesis of silver nanoparticles by chemical reduction of a silver salt on cotton and wool textiles is reported herein. The synthesis can be advantageously performed in an aqueous system when compared with an ethanolic system. SEM studies confirmed the presence of silver nanoparticles on the treated textiles, and elemental analysis by ICP revealed that, for the aqueous system, up to 3 and 4 mg of silver per gram were deposited per gram of cotton and wool fabric, respectively. This represented an increase of up to 16-fold for cotton and 3-fold for wool compared with the ethanolic system. Thus, the difference between the aqueous and ethanolic systems was more evident for cotton, albeit more silver was deposited on wool samples in all conditions. An increase in the amount of reducing agent present resulted in more silver being deposited on the textiles when using an aqueous system. The use of water presents a great advantage for possible scale-up of the method. This simple method can be applied to produce textiles for biomedical applications or presenting conductive properties. (C) 2012 Elsevier B.V. All rights reserved.

The final thermally stimulated discharge current method allows a better selection of the experimental conditions for sample polarization. By decreasing the ratio between the charging time and the discharging time, the apparent peak is of the same order of magnitude as the genuine peaks and there is only a partial overlap between then. Two peaks have been identified for polyamide 11, one associated with the glass transition around 60 degrees C and the second associated with the Curie transition around 96 degrees C.