The human dietary selenium requirement in China has been estimated by various methods. The minimum dietary selenium requircment for the prevention of Keshan disease (KD) was found to be around 17 μg/d. On the other h...The human dietary selenium requirement in China has been estimated by various methods. The minimum dietary selenium requircment for the prevention of Keshan disease (KD) was found to be around 17 μg/d. On the other hand, an intake of 40 μg/d is required to maintain the plasma glutathione peroxidase (GPx) activity at plateau. Hence 40 μg/d is considered as the adequate dietary selenium requirement. Studies conducted in a chronic selenosis area indicate thai the toxic dietary selenlum inlake (adverse effect level), which would maintain the characteristic fingernail changes, was approximately 1600 μg/d. The mean value of dietary selenium intakes, which enabled the five patients to recover from fingernail lesions, was found to be 819 ±126μg/d. At a 95% confidence limit, the lower limit is around 600μg/d. Therefore, 600 and 400μg/d were suggested as the individual daily maximum safe selenium intake and the safe dietary selenium intake, respectively,The results were used in the prevention of Se-related endemic KD and Kashin-Beck disease (KBD)展开更多
The equilibrium and kinetic characteristics of the adsorption of erythromycin to Sepabeads SP825 were determined.The equilibrium data in a batch system was well described by a Langmuir isotherm.The separation performa...The equilibrium and kinetic characteristics of the adsorption of erythromycin to Sepabeads SP825 were determined.The equilibrium data in a batch system was well described by a Langmuir isotherm.The separation performance was investigated in a fixed-bed system with respect to the adsorption superficial velocity,ionic strength and pH.A mathematical model was used to simulate the mass transfer mechanism,taking film mass transfer,pore diffusion and axial dispersion into account.The model predictions were consistent with the experi-mental data and were consequently used to determine the mass transfer coefficients.展开更多
文摘The human dietary selenium requirement in China has been estimated by various methods. The minimum dietary selenium requircment for the prevention of Keshan disease (KD) was found to be around 17 μg/d. On the other hand, an intake of 40 μg/d is required to maintain the plasma glutathione peroxidase (GPx) activity at plateau. Hence 40 μg/d is considered as the adequate dietary selenium requirement. Studies conducted in a chronic selenosis area indicate thai the toxic dietary selenlum inlake (adverse effect level), which would maintain the characteristic fingernail changes, was approximately 1600 μg/d. The mean value of dietary selenium intakes, which enabled the five patients to recover from fingernail lesions, was found to be 819 ±126μg/d. At a 95% confidence limit, the lower limit is around 600μg/d. Therefore, 600 and 400μg/d were suggested as the individual daily maximum safe selenium intake and the safe dietary selenium intake, respectively,The results were used in the prevention of Se-related endemic KD and Kashin-Beck disease (KBD)
文摘The equilibrium and kinetic characteristics of the adsorption of erythromycin to Sepabeads SP825 were determined.The equilibrium data in a batch system was well described by a Langmuir isotherm.The separation performance was investigated in a fixed-bed system with respect to the adsorption superficial velocity,ionic strength and pH.A mathematical model was used to simulate the mass transfer mechanism,taking film mass transfer,pore diffusion and axial dispersion into account.The model predictions were consistent with the experi-mental data and were consequently used to determine the mass transfer coefficients.
