Thin films of copper sulphide with thickness up to 0.5 µm were deposited at 70 • C on glass substrates from a solution containing copper(II) chloride, sodium thiosulphate and dimethylthiourea. As prepared and after annealing at 200 • C in N 2 (100 millitorr), these films showed x-ray diffraction patterns matching that of the mineral covellite (CuS). Annealing the films for 1 h each at 300 • C and 400 • C in nitrogen resulted in their conversion to Cu 1.8 S (digenite) and Cu 1.96 S (chalcocite), respectively. The reduction in sulphur content of the films is evident in the x-ray florescence spectra. The sheet resistance of the films varied with annealing temperature. For a film of 0.5 µm thickness, the observed sheet resistance values are: 180 / (as prepared), 6 / (200 • C), 17 / (300 • C) and 30 / (400 • C). The low sheet resistance (and thus the high conductivity, 10 3 −1 cm −1 ) leads to a high near-infrared reflectance for the films, 65% (CuS) and 40% (Cu 1.96 S), at a wavelength of 2500 nm. Analyses of the optical band gap of the films indicate an indirect gap of 1.55 eV for CuS and Cu 1.8 S and 1.4 eV for Cu 1.96 S.

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Catalytic steam reforming of ethanol (SRE) is a promising route for the production of renewable hydrogen (H 2 ). This article reviews the influence of doping supported-catalysts used in SRE on the conversion of ethanol, selectivity for H 2 , and stability during long reaction periods. In addition, promising new technologies such as membrane reactors and electrochemical reforming for performing SRE are presented.

The susceptibility of Trypanosoma cruzi epimastigotes to lysis by normal or immune sera in a complement-dependent reaction has been reported, but the effects induced directly by immune serum depleted of complement remain unstudied. The aim of this work was to study the ultrastructural alterations induced in T. cruzi epimastigotes by immune mouse or rabbit sera with or without complement. A local isolate of T. cruzi (Queretaro) was used in all experiments. Immune sera were raised in both mouse and rabbit by immunization with T. cruzi epimastigote antigens. Light microscopy showed intense agglutination of epimastigotes when incubated with decomplemented mouse or rabbit immune sera. A distinctive ultrastructural feature of this agglutination pattern was the fusion of plasma membranes and a pattern of intercrossing between subpellicular microtubules. Agglutination was associated with fragmentation of nuclear membranes and swelling of cytoplasm, Golgi cisternae, endoplasmic reticulum, mitochondria and kinetoplast membranes. Agglutinated parasites also incorporated trypan blue stain. Results of [3H]-thymidine incorporation confirmed that epimastigotes exposed to specific antibodies in the absence of complement were incapable of proliferating. Ultrastructural changes observed in epimastigote micrographs incubated with decomplemented immune mouse sera were statistically significant (P<0.001) when compared with results obtained from images after incubation with decomplemented normal mouse sera.