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Liposomal microcapsules containing enzymes were prepared by proliposome method to improve a stability of enzymes under acidic conditions. Two model enzymes, ~-galactosidase and alkaline phosphatase, were encapsulated by the method wlth soybean lecithins, and their encapsulation behaviors were investigated. The highest encapsulation efficiency was obtained by using 25mg of the enzyme and 250mg of soybean lecithin (fi-galactosidase; 57.30/0, alkaline phosphatase; 53.0010). However, the microcapsules did ' not exhibit the stabilizing effect for ~-galactosidase at pH 3. Chitosan-coating was made for proliposome-capsules to keep enzymatic activity under acidic conditions. The microcapsules coated with >0.50/0 of chitosan 10 showed high stability at pH 3, and encapsulated ~Lgalactosidase was retained 80.70/0 of its activity. Similarly, alkaline phosphatase was highly stabilized by the encapsulation with chitosan-coating. No decrease in the residual activity of encapsulated alkaline phosphatase was observed at pH 5 for 60min, while uncapsulated one lost 53.30/0 of its activity. The activity of encapsulated alkaline phosphatase was kept 20.1 and 59.20/0 for 60min at pH 3 and 4, respectively, while uncapsulated alkaline phosphatase was completely inactivated at these pHs.

Poly-γ-glutamic acid (γ-PGA) from Bacillus subtilis (natto) with a high molecular weight (Av. M.W.=350,000) effectively inhibited the formation of insoluble calcium phosphate at Ca/P=0.5 (12.5 mM/25 mM) under the condition of 37°C and pH 7.4. Since decrease in inhibitory activity in γ-PGA was observed after the treatment by simulated gastric fluid (pH 1.2, 0.5% pepsin), γ-PGA was encapsulated by egg lecithin liposome to keep the inhibitory activity under gastric conditions. Encapsulation was done by dehydration-rehydration (DR) and reverse-phase-vesicle (REV) methods. Higher encapsulation efficiency (57.0%) was achieved by DR method. Turbidity measurement at 450 nm indicated the high stability of DR microcapsule, prepared with trehalose, against gastric juice. Encapsulated γ-PGA by DR method showed 93.3% residual inhibitory activity after the gastric juice treatment.

Porous RuO2/Ti electrodes were prepared from RuO2La2O3/Ti (Ru:La=7:3) electrodes with the complete dissolution of lanthanum ions in H2SO4. Although the voltammetric charge of RuO2La2O3/Ti (Ru:La=7:3) electrodes partially decreased as lanthanum ions were dissolved, charges of the resulting porous RuO2/Ti electrodes were still about 20 times as large as those of the conventional RuO2/Ti electrodes prepared by the thermal decomposition method. The novel route through RuO2La2O3/Ti electrodes was significant for the preparation of porous RuO2/Ti electrodes.

RuO 2 - Re 2 O 3 /Ti (Ru: Re 7:3) electrodes prepared from the thermal decomposition of RuCl 3 and Re Cl 3 were much more porous than conventional RuO 2 /Ti electrodes. Porosities of the RuO 2 - Re 2 O 3 /Ti electrodes depended on the ionic radii of the rare earth ions. Rare earth ions added to electrodes to prepare the RuO 2 - Re 2 O 3 /Ti electrodes were completely dissolved in the acid solution. After dissolution of the rare earth ions, the voltammetric charges of the resulting RuO 2 /Ti electrodes were still large. Rare earth chlorides were effective as pore initiators in preparing porous RuO 2 /Ti electrodes, and were recovered after the preparation as catalysts.

Porous RuO2/Ti electrodes were prepared from RuO2La2O3/Ti (Ru:La=7:3) electrodes with the complete dissolution of lanthanum ions in H2SO4. Although the voltammetric charge of RuO2La2O3/Ti (Ru:La=7:3) electrodes partially decreased as lanthanum ions were dissolved, charges of the resulting porous RuO2/Ti electrodes were still about 20 times as large as those of the conventional RuO2/Ti electrodes prepared by the thermal decomposition method. The novel route through RuO2La2O3/Ti electrodes was significant for the preparation of porous RuO2/Ti electrodes.

RuO 2 - Re 2 O 3 /Ti (Ru: Re 7:3) electrodes prepared from the thermal decomposition of RuCl 3 and Re Cl 3 were much more porous than conventional RuO 2 /Ti electrodes. Porosities of the RuO 2 - Re 2 O 3 /Ti electrodes depended on the ionic radii of the rare earth ions. Rare earth ions added to electrodes to prepare the RuO 2 - Re 2 O 3 /Ti electrodes were completely dissolved in the acid solution. After dissolution of the rare earth ions, the voltammetric charges of the resulting RuO 2 /Ti electrodes were still large. Rare earth chlorides were effective as pore initiators in preparing porous RuO 2 /Ti electrodes, and were recovered after the preparation as catalysts.