Acetate and electricity generation from methane in conductive fiber membrane- microbial fuel cells.

Microbial conversion of methane to electricity, fuels, and liquid chemicals has attracted much attention. However, due to the low solubility of methane, it is not considered a suitable substrate for microbial fuel cells (MFCs). In this study, a conductive fiber membrane (CFM) module was constructed as the bioanode of methane-driven MFCs, directly delivering methane. After biofilm formation on the CFM surface, a steady voltage output of 0.6 to 0.7 V was recorded, and the CFM-MFCs obtained a maximum power density of 64 ± 2 mW/m2. Moreover, methane oxidation produced a high concentration of intermediate acetate (up to 7.1 mM). High-throughput 16S rRNA gene sequencing suggests that the microbial community was significantly changed after electricity generation. Methane-related archaea formed a symbiotic consortium with characterized electroactive bacteria and fermentative bacteria, suggesting a combination of three types of microorganisms for methane conversion into acetate and electricity.

Development of national neglect norm for urban primary school students of China / 中华预防医学杂志

<p><b>OBJECTIVE</b>To develop the national neglect norms for urban primary school students in China.</p><p><b>METHODS</b>According to multi-stage stratified cluster sampling principle, 24 cities of 13 provinces (municipalities) in China were selected during December 1 to 31, 2008. A total of 1491 students in grade 1 - 3 and 2236 students in grade 4 - 6 were selected. Questionnaire was designed by authors and the final norms were determined through several statistical analysis methods, such as item analysis method, factor analysis method, reliability analysis method. The reliability analysis and validity analysis were used to test the stability and reliability of the norms. The evaluation criteria of the scale was determined by the percentile method, then the initial development of the norm was completed.</p><p><b>RESULTS</b>The two questionnaires of grade 1 - 3 and grade 4 - 6 students consisted of 55 and 57 items, respectively, whose item loadings were ranged from 0.301 to 0.687 and 0.321 to 0.730, which met the statistical requirements. For grade 1 - 3 students, the scale's total Cronbach α coefficients was 0.914, the total split-half reliability coefficients was 0.896, the Cronbach α coefficients of four level was above 0.737 except medical and social neglect, split-half reliability was ranged from 0.461 to 0.757; for grade 4-6 students, the scale's total Cronbach α coefficients was 0.916, split-half reliability was 0.883, except social neglect, the Cronbach α coefficients of other level was ranged 0.457 to 0.856, split-half reliability was ranged from 0.500 to 0.798. The total neglect cut-off score of the two scales grade 1-3 and 4-6 were 125 and 155, respectively.</p><p><b>CONCLUSION</b>The structure of two norms was reasonable. The scales have good stability and reliability.</p>

Comparative toxicity of nano-ZnO and bulk ZnO suspensions to zebrafish and the effects of sedimentation, ˙OH production and particle dissolution in distilled water.

With the common application of nanoscale zinc oxide (nZnO) and significant potential for its release directly into aquatic environments, it is urgent to carry out research on ecotoxicological impact of nZnO. The characterization of nZnO, the amount of ˙OH in suspensions in the presence of light and the acute toxicity of nZnO and its bulk counterpart suspensions, as well as the acute toxicity of Zn(2+) solution to zebrafish (Danio rerio) at 96 h were studied. It was found that nZnO aggregated into irregular shapes in suspensions, and showed a relationship between its size distribution and concentration. In the presence of light, nZnO suspensions could generate ˙OH, the concentration of which increased with time. Although it was generally thought that ˙OH played a role in the biotoxicity to zebrafish, similar toxicity was observed for the nZnO and bulk ZnO suspensions (96 h LC(50) 3.969 mg L(-1), 2.525 mg L(-1), respectively). Furthermore, the sedimentation of nZnO and bulk ZnO in suspensions, and the accumulation of Zn in zebrafish were studied. The results showed that dissolved Zn(2+), from nZnO and bulk ZnO in suspensions, were toxic to zebrafish, while the aggregation and sedimentation of nZnO suspensions reduced the toxicity of nZnO. However, Zn(2+) may not be the main source of acute toxicity of nZnO and bulk ZnO to zebrafish. The experimental results highlight the importance of a systematic assessment of toxicity mechanisms of metal oxide nanoparticles (NPs) to determine definitively whether their toxicity is caused by nano-effects.