Thiago Lopes

In situ electrochemical quantification of active sites in Fe–N/C non-precious metal catalysts

The economic viability of low temperature fuel cells as clean energy devices is enhanced by the development of inexpensive oxygen reduction reaction catalysts. Heat treated iron and nitrogen containing carbon based materials (Fe–N/C) have shown potential to replace expensive precious metals. Although significant improvements have recently been made, their activity and durability is still unsatisfactory. The further development and a rational design of these materials has stalled due to the lack of an in situ methodology to easily probe and quantify the active site. Here we demonstrate a protocol that allows the quantification of active centres, which operate under acidic conditions, by means of nitrite adsorption followed by reductive stripping, and show direct correlation to the catalytic activity. The method is demonstrated for two differently prepared materials. This approach may allow researchers to easily assess the active site density and turnover frequency of Fe–N/C catalysts.

The intriguing poison tolerance of non-precious metal oxygen reduction reaction (ORR) catalysts

Electrochemical devices such as fuel cells are key to a sustainable energy future. However the applicability of such under realistic conditions is not viable to date. Expensive precious metals are used as electrocatalysts and contaminants present in the operating media poison the utilized catalysts. Here the one pot synthesis of a highly active, self-supporting and surprisingly poison tolerant catalyst is reported. The polymerisation of 1,5-diaminonaphthalene provides self-assembled nanospheres, which upon pyrolysis form a catalytically active high surface area material. Tolerance to a wide range of substances that poison precious metal based catalysts combined with high electrocatalytic activity might enable numerous additional technological applications. In addition to fuel cells these could be metal–air batteries, oxygen-depolarized chlor-alkali cathodes, oxygen sensors, medical implantable devices, waste water treatment and as counter electrodes for many other sensors where the operating medium is a complex and challenging mixture.

Establishment of the Brazilian telehealth network for paediatric oncology.

A telemedicine network has been established in Brazil to support distance medical practice in paediatric oncology. ONCONET comprises a national network of universities, research institutes and medical institutions. The system is Web-based and hosted on a high-performance computing infrastructure based on clusters of computers. It is based on open-source software, designed to provide high performance, fault tolerance and high availability. The ONCONET began operation in 2004. Currently, 30 hospitals affiliated to the Brazilian Society for Paediatric Oncology are users of the ONCONET. Six hospitals are connected by broadband access through the National Education and Research Network and 24 by conventional Internet access. The Multimedia Patients Registry also became operational in 2004, and its database contains information on 3200 patients from the 30 hospitals. The technological platform was notable for its low production cost. It thus appears to be a sustainable solution to the problem of delivering continuing medical education in a large country with widely dispersed health professionals.

Efeito dos dióxidos de enxofre e de nitrogênio no desempenho de uma célula a combustível de membrana de intercâmbio de prótons

There is presently much interest in the clean and efficient generation of energy by proton exchange membrane fuel cells (PEMFC), using hydrogen as fuel. The generation of hydrogen by the reforming of other fuels, anaerobic fermentation of residual waters and other methods, often produce contaminants that affect the performance of the cell. In this work, the effect of gaseous SO2 and NO2 on the performance of a H2/O2 single PEMFC is studied. The results show that SO2 decreases irreversibly the performance of the cell under operating conditions, while NO2 has a milder effect that allows the recovery of the system.

Web-based patient records and treatment guidelines in paediatric oncology

We have established a Web-based system in Brazil offering health information in childhood cancer and services such as electronic patient records and treatment protocols. The system was based on open-source software. The database has records for about 3200 patients from 30 Brazilian hospitals. An evaluation by doctors from the six hospitals comprising the Neuroblastoma Cooperative Group was positive, mainly because the system allows easy online access, but also because the electronic register performs data validation when information is inserted. Our experience shows that it is possible to use a Web-based system to provide paediatric cancer services at a distance.

Real time immersive visualization and manipulation of the visible human data set

The aim of this paper is to present a real time immersive visualization and manipulation of the full color visible human dataset. A data glove and stereo shutter glasses were used to provide interactive and stereoscopic 3D visualization of this set of images in a multiprojection immersive environment.