The influence of dioxide chloride on water quality of Balneário Camboriú beach, Brazil.

Since February 1999, the Municipal Wastewater Treatment Plant (MWTP) of Balneário Camboriú, Brazil, started a complementary treatment with ClO(2) application on its effluent. It was realized to minimize its impacts caused by increase of the population during summer. This study was realized in order to verify the influence of this compound in the water quality and the environmental evaluations. Samples of surface water were collected in this environment between January 1997 and June 2001 for chemical and microbiological surveys. The results had shown that after application of ClO(2), fecal coliforms were decreased about six times in the beach (2.3 x 10(3) to 3.5 x 10(2) MPN/100 ml) and three times in the river (3.3 x 10(4) to 1.0 x 10(4) MPN/100 ml), during summer time. NH(4) (+) showed an increase of about four times and 1.5 times, respectively, to beach and river. These results are showing the influence of ClO(2) on chemical and microbiological parameters.

Magnetic resonance of a dextran-coated magnetic fluid intravenously administered in mice.

Magnetic resonance was used to investigate the kinetic disposition of magnetite nanoparticles (9.4 nm core diameter) from the blood circulation after intravenous injection of magnetite-based dextran-coated magnetic fluid in female Swiss mice. In the first 60 min the time-decay of the nanoparticle concentration in the blood circulation follows the one-exponential (one-compartment) model with a half-life of (6.9 +/- 0.7) min. The X-band spectra show a broad single line at g approximately 2, typical of nanomagnetic particles suspended in a nonmagnetic matrix. The resonance field shifts toward higher values as the particle concentration reduces, following two distinct regimes. At the higher concentration regime (above 10(14) cm(-3)) the particle-particle interaction responds for the nonlinear behavior, while at the lower concentration regime (below 10(14) cm(-3)) the particle-particle interaction is ruled out and the system recovers the linearity due to the demagnetizing field effect alone.