Methane, Nitrous Oxide and Ammonia generation in full-scale swine wastewater purification facilities

The activated sludge process to remove nitrogen and biochemical oxygen demand （BOD） is reportedly cost-effective for swine wastewater treatment, and it use has thus increased in pig farming. Nitrous oxide （N20） is generated on farms as an intermediate product in nitrification and denitrification, and methane （CH4） is also generated from organic degradation under anaerobic conditions by microorganisms in manure or wastewater. This study was carried out at five activated sludge treatment facilities across Japan between August 2014 and January 2015. Measurements were conducted over several weeks at wastewater purification facilities for swine farms： two in Chiba prefecture （East Japan）, two in Okayama prefecture （West Japan）, and one in Saga （Southern Japan）. Taking several environmental fluctuations into account, we collected measurement data continuously day and night, during both high-temperature and low-temperature periods. The results indicated that CH4 and N20 emission factors were 0.91% （kgCHa·kg volatile solids^-1） and 2.87% （g N2O-N·kg total N^-1）, respectively. Ammonia emissions were negligible in all of the measurements from the wastewater facilities. The N20 emission factor calculated under this experiment was low compared to our previous finding （5.0%; g N2O-N·kg N^-1） in a laboratory experiment. In contrast, the CH4 emission factor calculated herein was rather high compared to the laboratory measurements. There was great variation in daily GHG emission factors measured in the actual wastewater treatment facilities. In particular, the N2O emission rate was affected by several environmental conditions at each facility location, as well as by the management of the wastewater treatment.

多巴胺转运体SPECT显像中显像剂分布的定量分析有助于图像的客观解读

目的多巴胺转运体（DAT） SPECT显像时，显像剂分布的定量分析能在视觉分析的基础上增加其客观性。该研究旨在评估显像剂分布的定量指标——分形维数（FD）的诊断作用，并将其与常规定量指标——特异性结合率（SBR）进行比较；同时评估SBR/FD组合指标（SBR除以FD）的诊断价值。方法行临床研究和模型研究。临床研究纳入150例患者，其中110例帕金森综合征（PS）患者和40例非PS患者。模型研究采用纹状体模型，将纹状体腔分为尾状核和壳核。计算SBR、FD和SBR/FD，并与数据库进行比较，以评估其诊断价值。采用Mann-Whitney检验和受试者工作特征（ROC）曲线分析法分析数据。结果ROC曲线分析表明，FD具有较高的诊断效能[曲线下面积（AUC）为0.943]，其与SBR和FD （SBR/FD）联合应用比单独使用SBR有更高的诊断效能（AUC：0.964与0.899; P〈0.001）。SBR的灵敏度、特异性和准确性分别为79.1%、85.0%和80.7%，FD对应为84.5%、97.5%和88.0%，SBR/FD对应为92.7%、87.5%和91.3%。结论FD是反映DAT SPECT显像时显像剂分布的有价值的诊断指标。FD与SBR联合应用比单独应用的诊断价值更高。