该研究利用37℃培养的中温厌氧消化菌群为菌源,直接提温至50℃驯化培养,获得连续处理高浓度糖蜜废水的厌氧消化产甲烷菌群,并考察高温驯化过程中菌群结构及多样性的变化特征.结果表明,中温厌氧消化菌群直接转入高温培养后,在高浓度有机废水连续进料的条件下,厌氧消化过程能够快速启动生成甲烷,并在22 d后形成稳定的高温厌氧消化产甲烷菌群,平均甲烷生成效率为162.3 m L CH_4/g COD.乙酸和丙酸是厌氧发酵液内的2类主要有机酸,产气稳定期间的质量浓度分别为25.3和145.3 mg·L~(-1).转入高温培养后,菌群结构产生巨大变化,细菌变异程度强于古菌,并逐渐稳定成为以代谢糖、多种有机酸的细菌和产甲烷古菌为主要优势菌群的高温厌氧消化菌群.克隆结果显示细菌菌群以Thermacetogenium和Acetomicrobium faecal为主要优势菌群,分别占细菌克隆文库的33.44%和20.99%;古菌菌群以Methanosaeta和Methanoculleus为主要优势菌群,占古菌克隆文库的56.40%和39.75%.转入高温培养后,产甲烷古菌的总生物量下降,含量约为7.6×106拷贝/g活性污泥.研究结果对阐明温度选择压力对厌氧消化菌群结构与功能影响,改进高温厌氧消化菌群富集方法具有重要意义. 相似文献
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Objective: Although electric bicycle-related injuries have become the most common reason for hospitalization due to a road crash in China, no study has comprehensively investigated electric bicycle collisions and their impact on orthopedic injuries; such a study may provide evidence to support a new road safety policy.
Methods: A retrospective review of orthopedic injuries from electric bicycle collisions was performed in an urban trauma center. We collected variables including age, gender, location of fracture, presence of open or closed fractures, concomitant vascular, and neurologic injuries.
Results: A total of 2,044 cases were involved in electric bicycle collisions. The orthopedic injury victims were predominantly male and middle aged. The most common orthopedic injury was a femur fracture. Open fractures frequently involved the forearm and tibia/fibula. Male patients were more likely to suffer from multiple fractures and associated injuries than female patients. Fewer patients age 60 years old or older wore helmets at the time of the accident compared to those in other age groups.
Conclusions: Orthopedic injuries from electric bicycle-related accidents cause patients substantial suffering that could lead to serious social consequences. Helmet use and protective clothing or similar safety gear, especially for electric bicycle users, should be required to provide greater protection. 相似文献