Performance of the ANAMMOX process using multi- and single-fed upflow anaerobic sludge blanket reactors.

The performance of the ANAMMOX process was investigated in two identical laboratory-scale multi- and single-fed upflow anaerobic sludge blanket (UASB) reactors (denoted R1 and R0) at different hydraulic residence times (HRTs) varying from 2.06 to 1.52 h and NH4(+)-N inf concentrations ranging from 70 to 266 mg L(-1). The substrate removal efficiencies of both reactors decreased as HRT decreased and NH4(+)-N inf increased. The kinetics of these reactions were analyzed, and the Stover-Kincannon model was appropriate to describe the process kinetics of the reactors. In addition, an empirical model incorporating the influent substrate concentration and HRT adequately described R1. Shock experiments were conducted in which the reactors were subjected to transient shock loads. The results showed that the operation of R1 was more stable than that of R0, especially in response to the substrate shocks. Subsequently, the properties of the ANAMMOX granules and the effects of the feeding protocol on those properties were investigated.

Therapeutic effect of recombinant tissue plasminogen activator on acute cerebral infarction at different times.

BACKGROUND: The study aimed to compare the therapeutic effect of recombinant tissue plasminogen activator (rt-PA) on the onset of acute cerebral infarction (ACI) at different time points of the first 6 hours. METHODS: A retrospective analysis was conducted in 74 patients who received rt-PA thrombolysis treatment within 4.5 hours after ACI and another 15 patients who received rt-PA thrombolysis treatment between 4.5-6 hours after ACI. RESULTS: National Institute of Health Stroke Scale (NIHSS) scores were statistically decreased in both groups (P>0.05) at 24 hours and 7 days after ACI. There was no significant difference in modified ranking scores and mortality at 90 days after the treatment between the two groups (P>0.05). CONCLUSIONS: The therapeutic effect and mortality of rt-PA treatment in patients with ACI between 4.5-6 hours after the onset of the disease were similar to those in patients who received rt-PA within 4.5 hours after the onset of this disease. Therefore, intravenous thrombolytic therapy for ACI within 4.5-6 hours after ACI was effective and safe.

The evolution of Anammox performance and granular sludge characteristics under the stress of phenol.

The short- and long-term effects of phenol on anaerobic ammonium oxidation (Anammox) were evaluated. The short-term impact of phenol on Anammox activity was determined by a batch test, and an IC50 value of 678.2 mg L(-1) was calculated. Anammox granular sludge was equally seeded into two identical upflow anaerobic sludge blanket reactors (R0 and R1); synthetic wastewater without phenol was fed to R0 while with varied phenol was fed to R1 to study the long-term effects. The performance of R0 was stable, with a steadily rising nitrogen removal rate of 10.5-21.3 kg N m(-3)d ay(-1). However, the performance of R1 was significantly suppressed by an influent phenol concentration of 50 mg L(-1), and was recovered and stabilized by applying one or more control strategies. The phenol-mediated inhibition depressed the Anammox activity and biomass, and caused a change of stoichiometric ratios and granule characteristics.