Effect of phosphorus load on nutrients removal and N2O emission during low-oxygen simultaneous nitrification and denitrification process.

Three laboratory scale anaerobic-aerobic (low-oxygen) SBRs (R1, R2 and R3) were conducted at different influent phosphorus concentration to evaluate the impacts of phosphorus load on nutrients removal and nitrous oxide (N2O) emission during low-oxygen simultaneous nitrification and denitrification (SND) process. The results showed that TP and TN removals were enhanced simultaneously with the increase in phosphorus load. It was mainly caused by the enrichment of polyphosphate accumulating organisms (PAOs) under high phosphorus load and low COD/P ratio (<50), which could use nitrate/nitrite as electron acceptors to take up the phosphorus. N2O emission was reduced with increasing phosphorus load. N2O-N emission amount per cycle of R3 was 24.1% lower than that of R1. It was due to the decrease of N2O yield by heterotrophic denitrification. When the phosphorus load increased from R1 to R3, heterotrophic denitrification (D) ranged from 42.6% to 36.6% of the N2O yield.

EGF-functionalized single-walled carbon nanotubes for targeting delivery of etoposide.

To enhance the therapeutic potential of etoposide (ETO), we devised a targeted drug delivery system (TDDS) of epidermal growth factor-chitosan-carboxyl single-walled carbon nanotubes-ETO (EGF/CHI/SWNT-COOHs/ETO) using modified SWNTs (m-SWNTs) as the carrier, EGF-functionalized SWNTs (f-SWNTs) as the targeted moiety and ETO as the drug. After SWNT-COOHs were conjugated with CHI (CHI/SWNT-COOHs/ETO), they displayed high solubility and stable dispersion in aqueous solution. The drug loading capacity was approximately 25-27%. The m-SWNTs and f-SWNTs had only slight cytotoxicity. ETO was released from EGF/CHI/SWNT-COOHs/ETO at low pH and taken up by tumour cells via adenosine triphosphate (ATP)-dependent endocytosis. The cell death induced by EGF/CHI/SWNT-COOHs/ETO was as much as 2.7 times that due to ETO alone. In summary, these results demonstrated that our TDDS had a greater anticancer effect than free ETO in vitro.