Neuroprotective Effects of Electroacupuncture Preventive Treatment in Senescence-Accelerated Mouse Prone 8 Mice.

OBJECTIVE: To investigate the preventive treatment effects of electroacupuncture (EA) on cognitive changes and brain damage in senescence-accelerated mouse prone 8 (SAMP8) mice. METHODS: The 5-month-old male SAMP8 and age-matched homologous normal aging mice (SAMR1) were adopted in this study. EA stimulation at Baihui (GV 20) and Yintang (EX-HN 3) was performed every other day for 12 weeks, 4 weeks as a course. Morris water maze test and Nissl-stained with cresyl violet were used for cognitive impairments evaluation and brain morphometric analysis. Amyloid-ß (A ß) expression in hippocampus and parietal cortex was detected by immunohistochemistry, and apoptosis was observed by TUNEL staining. RESULTS: After 3 courses of EA preventive treatment, the escape latencies of 8-month-old SAMP8 mice in EA group were significantly shortened than those of un-pretreated SAMP8 mice. Compared with SAMR1 mice, extensive neuronal changes were visualized in the CA1 area of hippocampus in SAMP8 mice, while these pathological changes and attenuate cell loss in hippocampal CA1 area of SAMP8 mice markedly reduced after EA preventive treatment. Furthermore, A ß expression in hippocampus and parietal cortex of SAMP8 mice decreased significantly after EA treatment, and neuronal apoptosis decreased as well. CONCLUSION: EA preventive treatment at GV 20 and EX-HN 3 might improve cognitive deficits and neuropathological changes in SAMP8 mice, which might be, at least in part, due to the effects of reducing brain neuronal damage, decreasing neuronal apoptosis and inhibiting A ß-containing aggregates.

[Realization of Shortcut Nitrification in the ABR-MBR Process Treating Domestic Wastewater].

The operational control conditions for realizing shortcut nitrification in the membrane bioreactor (MBR) process was investigated in a lab-scale anaerobic baffled reactor (ABR)-MBR combined system, which laid the foundation for further research on the performance of denitrification phosphorus removal in the system. The experimental results under different conditions showed that shortcut nitrification in the MBR was achieved by controlling the dissolved oxygen (DO) concentration to low levels (0.5-1.0 mg·L-1 to 0.3-0.7 mg·L-1) and changing the effective volume of the MBR to control hydraulic retention time (HRT), with the HRT in the ABR equal to 6 h, sludge reflux ratio of 100%, NOx--N reflux ratio of 300%, and temperature of 30℃±2℃. Finally, the shortcut nitrification deteriorated as the HRT in the MBR increased from 3 h to 5 h, with nitrite accumulation rate dramatically dropping from 60% to 15%. The analysis of the influencing factors of shortcut nitrification showed that maintaining low DO concentration (0.3-0.7 mg·L-1) and gradually shortening HRT were the key factors. The pH, free ammonia (FA), free nitrous acid (FNA), temperature, and sludge retention time (SRT) had a slightly positive effect on shortcut nitrification. During the period of shortcut nitrification, a stable and high efficiency removal of COD and NH4+-N were achieved, and the average concentration of the effluent of COD and NH4+-N, whose removal rates were above 90%, were below 50 mg·L-1 and 2 mg·L-1, respectively, and the removal efficiency of total nitrogen (TN) reached 72%.

[Effects of Influent C/N Ratios on Denitrifying Phosphorus Removal Performance Based on ABR-MBR Combined Process].

An ABR-MBR integrated reactor based on a combination of the anaerobic baffled reactor (ABR) with the microbial phase separation and membrane bioreactor (MBR) with high-effect entrapment was constructed and the circulation and interactivity of the combined process were examined by adding nitrate recycling and sludge reflux. By increasing the influent COD to adjust the COD/TN ratio, the influence of the mechanism on the denitrifying phosphorus removal performance under the condition of continuous-flow was investigated. The results showed that the average effluent concentration of soluble phosphorus under different influent C/N conditions were 0.22, 0.34, 0.39, 0.42, and 2.45 mg·L-1 and the low influent C/N ratio was beneficial to phosphate removal. When the influent C/N was 4.8-6.0, the average removal rates of COD, TN, and soluble PO43--P were more than 87%, 76%, and 93%. In addition, when the influent C/N ratio was 3.6-6.0, the removal of TN was proportional to the anoxic phosphorus uptake of ABR and conducive to the removal of TN after increasing the influent COD concentration. Higher C/N ratios of the influent improved the removal of TN at this stage. Finally, the C/N ratio of 6 was suggested to achieve the simultaneous removal of nitrogen and phosphorus.

[Optimization of Denitrifying Phosphorus Removal Performance Based on ABR-MBR Combined Process].

An integrated process based on combination of the anaerobic baffled reactor(ABR)-membrane bioreactor(MBR) was adopted to treat domestic sewage with low C/N ratio. In order to realize the function of highly efficient denitrifying phosphorus removal, nitrate recycling ratio and sludge recycle ratio were optimized in this study. The results indicated that the optimized denitrifying phosphorus removal efficiency was achieved under the conditions of organic loading rate of 2.0 kg·(m3·d)-1 in ABR, total hydraulic retention time (HRT) of ABR-MBR at 9 h, the SRT at 15 d, sludge reflux ratio of 100%, and nitrate recycling ratios set to 300%. The average removal rates of TN and soluble PO43--P were 84% and 94%, the amount of phosphorus removed by denitrifying accounted for 87% of the total phosphorus removed, and the average effluent concentration for TN and soluble phosphorus were 12.98 mg·L-1 and 0.43 mg·L-1 respectively.