RESUMEN
To improve nitrogen removal efficiency (NRE) and achieve homogenous distribution of anammox sludge and substrate, a new substrate equalization theory and a cumulative overload index was proposed for multifed upflow anaerobic sludge bed (MUASB) reactors with mature anammox granules. The performance and flow patterns of MUASB reactors were investigated under various influent conditions. The results showed that the nitrogen removal performance and stability of MUASB reactors could be optimized by minimizing the cumulative load. The NRE gradually increased from 83.3 ± 2.2 %, 86.8 ± 4.2 % to 89.3 ± 4.1 % and 89.7 ± 1.6 % in feeding flow tests and feeding port tests, respectively. Furthermore, the flow patterns were compared based on residence time distribution and computational fluid dynamics, indicating that a better equilibrium distribution of microorganisms and substrates could be achieved in the MUASB reactors under the lowest cumulative load. Therefore, substrate equalization theory can be used to optimize the nitrogen removal performance of MUASB reactors with low-carbon footprints.
Asunto(s)
Reactores Biológicos , Nitrógeno , Aguas del Alcantarillado , Aguas del Alcantarillado/microbiología , Anaerobiosis , Nitrógeno/metabolismo , Oxidación-Reducción , HidrodinámicaRESUMEN
<p><b>OBJECTIVE</b>To study the antitumor effects and associated mechanisms of extract of the Smilax china L. rhizome (SCR) on ovarian cancer cells.</p><p><b>METHODS</b>Ovarian cancer cells A2780 were treated with different concentrations of SCR extract (SCRE), and compared with controls. Effects on cell growth were evaluated by cell counting kit-8 (CCK-8) assay; proliferation effects by EdU incorporation assay; cell cycle by propidium iodide staining; apoptosis by annexin V-fluorescein isothiocyanate/propidium iodide; cellular distribution of nuclear factor-κB (NF-κB) by immunofluorescence; protein levels of NF-κB, caspase-3, poly-adenosine diphosphate (ADP)-ribose polymerase (PARP), Bcl-2-associated X protein (Bax), cellular inhibitor of apoptosis (cIAP)-1, anti-X-linked inhibitor of apoptosis protein (XIAP), B-cell lymphoma-extra large (Bcl-XL), B-cell lymphoma-2 (Bcl-2) and AKT by Western blotting; and effects of SCRE combined with cisplatin or adriamycin on A2780 cells by CCK-8 assay.</p><p><b>RESULTS</b>SCRE suppressed A2780 cell proliferation in a dose-dependent manner (P<0.05,P<0.01), arrested cells in G2/M phase and induced apoptosis by activating caspase-3, PARP and Bax. SCRE treatment also correlated with inhibition of NF-κB and downregulation of Bcl-2, Bcl-XL, cIAP-1, XIAP and AKT. SCRE can promote chemosensitivity to cisplatin and adriamycin in A2780 cells (P<0.01).</p><p><b>CONCLUSION</b>SCR effectively inhibits NF-κB, induces apoptosis and reduces chemoresistance to cisplatin and adriamycin in ovarian cancer cells, which might be its molecular basis for treating ovarian cancer.</p>