[Rapid enrichment and cultivation of denitrifying phosphate-removal bacteria and its identification by fluorescence in situ hybridization technology].

The present work focused on a rapid enrichment and cultivation of denitrifying phosphate-removal bacteria (DPB) in a membrane bio-reactor(MBR) by using A2/O anaerobic sludge from a wastewater treatment plant as seed, as well as providing an identification method. In the experiments, sodium acetate was used as the carbon source and a certain amount of nitrate was added to the MBR in the anoxic stage. Results showed that, with the efficient trap of the hollow-fiber membrane module, the proportion of DPB in all the phosphate-accumulating organisms (PAOs) increased from 24% to 93% within 35 days after two-stage's cultivation including anaerobic/aerobic and anaerobic/anoxic, during which the removal efficiency of nitrogen and phosphorus reached more than 90%. The activated sludge was identified by combining a regular method and the fluorescence in situ hybridization (FISH) technique, which demonstrated that Pseudomonas sp. and Rhodocyclus sp. were the dominant bacteria in the used bioreactor.

[Synergistic effects of nano-sized magnetic particles and uncoupler to the characteristics of activated sludge].

For improving the performance and sludge settling property of an activated sludge reduction process with uncoupler, in this investigation, uncoupler and nano-sized magnetic particles were added simultaneously to a sequencing batch reactor for exploring their synergistic effects to the characteristics of activated sludge. The results showed that the volume reduction of sludge reached 41% with single 2,4,5-Trichlorophenol (TCP) Comparing with the control experiment, the biodegradability and settling properties of the activated sludge decreased. Under the actions of TCP combined with nano-sized magnetic particles, the volume reduction of sludge reached 34%, the removal efficiencies of COD, nitrogen, and phosphorus as well as the sludge settling property were not significantly influenced. After 31 d's operation, the dehydrogenase activity was improved by 10%-18% and exhibited an accumulative effect over time. It was observed with an optical microscope that the species and amounts of protozoon and metazoan increased and a compact structure of sludge floc was formed. The results also indicated that using nano-sized magnetic particles and uncoupler could restrict the yield of excess sludge and improve the performance of an activated sludge system.

[Prevalence and predictors of acute stress disorder after earthquake: findings from Wenchuan earthquake in China].

OBJECTIVE: To investigate the prevalence and predictors of acute stress disorder (ASD) in the victims affected by Wenchuan earthquake in China. METHODS: A random clustered sampling method was used. Of 891 victims enrolled in the study, 874 were completely assessed with the ASD constructive questionnaire and diagnosed with DSM-IV criteria. Sociodemographic variables were obtained. Also, the major symptoms of ASD (i.e., general symptoms to a traumatic event; dissociative symptoms; re-experiencing symptoms; hyper-arousal symptoms; avoidance symptoms) were recorded. RESULTS: The incidence rate of ASD was 12.59% (110/874). The incidence rates of ASD for female and male were 15.16% (72/475) and 9.52% (38/399) respectively. There was a significant difference between female and male on the incidence rate of ASD (chi(2) = 6.26, P = 0.01). Logistic regression indicated that the ASD diagnosis was predicted by gender (beta = 0.58, P = 0.01, OR = 1.79), the condition of casualties of family members (beta = 0.60, P = 0.01, OR = 1.82), and the condition of sharp properties loss (beta = 1.02, P = 0.01, OR = 2.76). CONCLUSION: The major earthquake should have great influence on mental health of victims. The efforts to reduce casualties and property loss might help to prevent ASD. Further research is needed on gender difference among traumatic events.