Corneal tissue preserved at -80°C was the best method for preservation as it maintained the sterility, thickness, optical transparency, mechanical strength and ultrastructural features.

Oxidation of benzaldehyde and p-nitrobenzaldehyde by cerium(IV) sulphate in aqueous sulphuric acid is strongly catalyzed by iridium(III) chloride. The complex formed between cerium(IV) and the organic substrate in the first equilibrium step gives another complex in the presence of iridium(III), which ultimately gives the corresponding aromatic acids as the product of oxidation. The order of the reaction follows first-order kinetics at low concentrations to zero order at higher concentrations of both the oxidant and organic substrate. The rate is directly proportional to the concentration of catalyst, but decreases sharply with increasing H + ions and cerium(III) concentrations, while change in ionic strength of the medium or the concentration of acetic acid and Cl -ions has no effect on the rate.

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The aromatic compounds p-nitrobenzaldehyde, p-hydroxybenzaldehyde, naphthalene, toluene, catechol, quinol, aniline and toluidine dissolved in aqueous acetic acid or aqueous medium were oxidized in quantitative to good yields by 50% H 2 O 2 in the presence of traces of RuCl 3 (∼10 −8 mol; substrate/catalyst ratio 1488 : 1 to 341 250 : 1). Conditions for highest yields, in the most economical way, were obtained. Higher catalyst concentrations decrease the yield. Oxidation in aromatic aldehydes is selective at the aldehydic group only. In the case of hydrocarbons, oxidation results in the introduction of a hydroxyl group with >85% (in the case of toluene) selectivity for the ortho position. Formation of low-molecular-weight polyaniline was reduced to 10%, along with 90% formation of higher molecular weight polyaniline. In this new, simple and economical method, which is environmentally safe and requires less time, oxo-centered carboxylate species of ruthenium(III) in acetic acid medium and hydrated ruthenium(III) chloride in aqueous medium probably catalyze the oxidation.