Adsorption behaviors of Cu2Zn2SOD on mercury electrodes were studied by the electrostatic capillary curve and the relationship between polarographic ultimate current and height of mercury column in the absence of the mediators. The effects of impure and denatured SOD on cyclic voltammogram were investigated, confirming that no denaturation was caused during adsorption on mercury electrodes. Double potential step chronocoulometry has confirmed that SOD adsorption on mercury electrode to be the absorption of monomolecular layer.
New oscillating reactions catalyzed by a bistetraazacrocyclic nickel (Ⅱ) complex Ni2L(ClO4), where L is bis(11,13 dimethyl 1,4,7,10 tetraza 10,13 cyclotridecadien 12 ylidene), in acidic bromate medium have been studied. We obtained the concentration ranges of main reactant within which the oscillations were observed in the system. We discussed the influence of temperature, Vc ,Br-, Ag+, Hg2+, acetonitrile or acrylamide on the oscillations. The results indicated that Br-played an important role in the control reaction progress and free radical might be involved in the reaction process. We recorded the oscillation trajectories of this system. It was different from classical BZ reaction and some other tetraazamacrocyclic complexes catalyzed system.
The nucleation, growth and aggregation of calcium oxalate(CaC 2O 4) crystals were comparatively investigated in five different mimetic systems: water, NaCl solution, artificial urine, healthy urine and lithogenic urine by using scanning electron microscopy(SEM). The effects of original concentration of calcium ion and oxalate ion and crystallization time on the morphology, density and the size of CaC 2O 4 crystals were discussed. In lithogenic urine, calcium oxalate monohydrate(COM) crystals were the dominant phase. However, a mixture of COM and calcium oxalate dihydrate(COD) with a molar ratio of about 3∶2 was obtained in the healthy urine. COD has a less affinity for renal tubule cell surface, so COD is easy to be expelled out from body and there is a less probability of stone-forming in the healthy urine. The fastest nucleation and growth of CaC 2O 4 crystals were obtained in water and NaCl solution, respectively. The size of CaC 2O 4 crystals decreases in the following order: NaCl solution>artificial urine>lithogenic urine>healthy urine>water.
