Enhanced phosphorus removal in the DAF process by flotation scum recycling for advanced treatment of municipal wastewater.

To remove phosphorus (P) from municipal wastewater, various types of advanced treatment processes are being actively applied. However, there is commonly a space limit in municipal wastewater treatment plants (MWTPs). For that reason, the dissolved air flotation (DAF), which is well known for small space and flexible application process, is preferred as an additive process to enhance the removal of P. A series of experiments were conducted to investigate the feasibility of flotation scum recycling for effective P removal from a MWTP using a DAF pilot plant over 1 year. The average increases in the removal efficiencies due to flotation scum recycling were 22.6% for total phosphorus (T-P) and 18.3% for PO4-P. A higher removal efficiency of T-P was induced by recycling the flotation scum because a significant amount of Al components remained in the flotation scum. The increase in T-P removal efficiency, due to the recycling of flotation scum, shifted from the boundary of the stoichiometric precipitate to the equilibrium control region. Flotation scum recycling may contribute to improving the quality of treated water and reducing treatment costs by minimizing the coagulant dosage required.

The role of alkoxy group on the A ring of isoflavones in the inhibition of interleukin-5.

Novel isoflavones were found to be potent inhibitors of interleukin-5 (Il-5). 5-Benzyloxy-3-(4-hydroxyphenyl)-4H-chromen-4-one (2a, 87.8% inhibition at 50 microM, IC50 = 15.3 microM) was initially identified as a potent inhibitor of IL-5. Its activity was comparable to that of budesonide or sophoricoside (1a). The benzyloxy group appeared to be critical for the enhancement of the IL-5 inhibitory activity. To identify the role of this hydrophobic moiety, 5-cyclohexylmethoxy (2d), 7-cyclohexylmethoxy (2e), 5-cyclohexylethoxy (2f), 5-cyclohexylpropoxy (2g), 5-(2-methylpropoxy) (2h), 5-(3-methylbutoxy) (2i), 5-(4-methylpentoxy) (2j) and 5-(2-ethylbutoxy) (2k) analogs were prepared and tested for their effects on the bioactivity of IL-5. Compounds 2d (IC50 = 5.8 microM), 2e (IC50 = 4.0 microM) and 2j (IC50 = 7.2 microM) exhibited the most potent activities. Considering the cLog P values of compounds 2 and the different three dimensional structures of 2d and 2e, the alkoxy group on ring A contributed to their cell permeability for the enhancement of activity, rather than playing a role in the ligand motif binding to the receptor. The optimum alkoxy group should be one that provides cLog P values of compounds 2 in the range of 4.13 to 4.39.

Simultaneous analysis of naltrexone and its major metabolite, 6-beta-naltrexol, in human plasma using liquid chromatography-tandem mass spectrometry: Application to a parent-metabolite kinetic model in humans.

We developed a method for simultaneously determining naltrexone, an opioid antagonist, and its major metabolite (6-beta-naltrexol) in plasma using LC/MS/MS. Three compounds, and naloxone as an internal standard, were extracted from plasma using a mixture of methyl-tertiary-butyl ether. After drying the organic layer, the residue was reconstituted in a mobile phase (0.1% formic acid-acetonitrile:0.1% formic acid buffer, 95:5, v/v) and injected onto a reversed-phase C(18) column. The isocratic mobile phase was eluted at 0.2ml/min. The ion transitions monitored in multiple reaction-monitoring modes were m/z 342-->324, 344-->326, and 328-->310 for naltrexone, 6-beta-naltrexol, and naloxone, respectively. The coefficient of variation of the assay precision was less than 11.520%, and the accuracy exceeded 93.465%. The limit of quantification was 2ng/ml for naltrexone and 7.2ng/ml for 6-beta-naltrexol. And the limit of detection was 0.1ng/ml for naltrexone and 0.36ng/ml for 6-beta-naltrexol. This method was used to measure the plasma concentration of naltrexone and 6-beta-naltrexol in healthy subjects after a single oral 50mg dose of naltrexone. This analytical method is a simple, sensitive, and accurate way of determining the pharmacokinetic profiles of naltrexone and its metabolites. The pharmacokinetic parameters were analyzed using both non-compartmental analysis performed for each subject according to standard methods and compartmental analysis with a parent-metabolite pharmacokinetic model that was fitted to the data, simultaneously, using the program ADAPT II. The tested parent-metabolite pharmacokinetic model successfully described the relationship between the plasma concentration of naltrexone and one of its major metabolites, 6-beta-naltrexol.