Auchere, F., R. Sikkink, C. Cordas, P. Raleiras, P. Tavares, I. Moura, and J. Moura. "
{Overexpression and purification of Treponema pallidum rubredoxin; kinetic evidence for a superoxide-mediated electron transfer with the superoxide reductase neelaredoxin}."
J Biol Inorg Chem. 9 (2004): 839-849.
Abstract{Superoxide reductases are a class of non-haem iron enzymes which catalyse the monovalent reduction of the superoxide anion O2- into hydrogen peroxide and water. Treponema pallidum (Tp), the syphilis spirochete, expresses the gene for a superoxide reductase called neelaredoxin, having the iron protein rubredoxin as the putative electron donor necessary to complete the catalytic cycle. In this work, we present the first cloning, overexpression in Escherichia coli and purification of the Tp rubredoxin. Spectroscopic characterization of this 6 kDa protein allowed us to calculate the molar absorption coefficient of the 490 nm feature of ferric iron
Zhang, S., L. Raniero, E. Fortunato, L. Pereira, N. Martins, P. Canhola, I. Ferreira, N. Nedev, H. Águas, and R. Martins. "
{Characterization of silicon carbide thin films prepared by VHF-PECVD technology}."
Journal of Non-Crystalline Solids. 338-340 (2004): 530-533.
Abstractn/a
A, Velhinho, Botas JD, Ariza E, Gomes JR, and Rocha LA. "
Tribocorrosion studies in centrifugally cast Al-matrix SiCp-reinforced functionally graded composites."
Advanced Materials Forum Ii. Vol. 455-456. Materials Science Forum, 455-456. 2004. 871-875.
AbstractThe present work reports results obtained from a series of preliminary experiments
aiming at complementing the current knowledge about the wear behaviour of centrifugally-cast
FGM Al/SiCp composites, through concurrent corrosion processes. Precursor MMC’s were
prepared by rheocasting, using 118.8 μm SiC particles and an Al-10Si–2.2 Mg alloy. Those MMC’s
were then molten and centrifugally cast in order to produce cylindrical FGMMC’s. Discs machined
from the top surface of each sample were tested against nodular cast iron pins, using an inverted
configuration pin-on-disc tribometer. Sliding tests took place at room temperature, over a 50000 m
sliding distance, with a sliding speed of 0.3 m s-1, under a 5 N normal load; both dry-sliding and
water-lubricated tests were performed. In order to elucidate the mechanisms involved, the wear
coefficients were calculated for each condition, and the samples were subjected to morphological
characterization via SEM/EDS. Concurrently, in the case of the water-lubrication tests, the
corrosion potential of the tribological pair was monitored. The results obtained show an increase in
material loss for the water-lubricated cases, although variations are registered depending on
reinforcing particle volume fraction. At the same time, the open circuit potential response of the
tribological pair may be correlated with the events of formation/destruction of the tribolayers.
]