Prokaryotic community structures in biogas plants with swine manure

采集了中国不同地区的13个猪粪原料沼气工程系统的沼液,利用16S rrnA基因扩增子高通量测序技术研究了原核微生物群落组成及多样性。结果表明,fIrMICuTES是猪粪原料沼气工程系统中的主导微生物,其次为bACTErOIdETES、PrOTEObACTErIA和CHlOrOflEXI。在相似的温度条件下,铵态氮与磷酸盐的比例是影响猪粪原料沼气工程系统原核微生物群落结构及多样性的主要因素。较高的铵磷比会富集fIrMICuTES门的菌群,尤其是ClOSTrIdIuM SEnSu STrICTO属;而较低的铵磷比则有利于bACTErOIdETES和PrOTEObACTErIA。不同营养类型产甲烷菌对高浓度铵态氮耐受程度不同(氢营养型产甲烷菌>METHAnOSArCInA>METHAnOSAETA),影响着产甲烷菌群落组成。产甲烷菌和互营菌的群落组成是影响沼气发酵产气效率的重要生物因素,高比例的氢型产甲烷菌和丙酸互营菌更有利于提高产甲烷效率。Slurry samples from 13 industrial biogas plants using swine manure as raw substrate were collected from different regions in China.The prokaryotic community compositions were investigated using 16S rRNA amplicon high-throughput sequencing technique.The results showed that Firmicutes was the most abundant phylum in these biogas plants, followed by Bacteroidetes, Proteobacteria and Chloroflexi.The ratio of ammonium to phosphate was the main factor affecting prokaryotic community structure and diversity for similar temperatures and substrates.A high ratio of ammonium to phosphate enriched Firmicutes, especially the genus Clostridium sensu stricto, while Bacteroidetes and Proteobacteria preferred a low ratio.Ammonium influenced the compositions of methanogens since their tolerance degrees to ammonium were different(hydrogenotrophic methanoges > Methanosarcina > Methanosaeta).Community compositions of methanogens and syntrophs were the most important biotic factors affecting biogas production rate.Biogas production rate could be increased by increasing the abundances of hydrogenotrophic methanoges and syntrophic propionate-oxidizing bacteria.国家重点基础研究发展计划项目(2013CB733502); 国家自然科学基金项目(41301271;41271260)~

Loop-Mediated Isothermal Amplification(LAMP) for Detection of Alicyclobacillus acidoterrestris in Foods

目的:利用环介导等温扩增技术建立食品中酸土环脂芽孢杆菌快速检测方法。方法:针对酸土环脂芽孢杆菌16S序列设计特异引物,再优选反应体系,用显色法检测实验结果。结果:该方法能够在63℃条件下1 H内检出食品中酸土环脂芽孢杆菌,所设计的引物有良好的特异性;灵敏度达6.7 Cfu/M l(弱阳性)。结论:该方法具有高效、特异性强和敏感性高等特点,可满足酸土环脂芽孢杆菌快速检测筛选的要求。Purpose: A loop-mediated isothermal amplification(LAMP) method was established for the detection of Alicyclobacillus acidoterrestris in foods.Methods: After optimization of the reaction conditions of LAMP including the concentrations of primers, reaction time and amplification temperature, the LAMP method was developed, and its sensitivity and specificity were evaluated.Results: The method was capable of rapidly and specifically detecting A.acidoterrestris in foods within 1 hour at a constant temperature of 63 ℃.The sensitivity of the method was 6.7 CFU/m L and the specificity was 100%.Conclusions: The LAMP method is efficient, highly sensitive and specific, and suitable for the rapid detection of A.acidoterrestris in various food samples.福建省漳州市自然科学基金项目(ZZ2012J16

关于“经济发展方式转变进程中的财税政策”的探讨(笔谈)

转变经济发展方式是当前中国的热门话题,而上海在城市发展中又肩负着率先转变的重要任务,在这一意义和背景下,2010年4月24日由上海金融学院学院主办、上海金融学院公共经济管理学院承办的“《中国城市财政发展报告2009/2010:促进‘两个中心’建设的上海城市财政》首发式暨‘经济发展方式转变进程中的财税政策’论坛“在我校举行。与会专家围绕经济发展方式转变进程中的财税政策的“趋势与目标“、“机遇和挑战“、“实施方略“和“地方实践“等四个专题进行研讨,各抒己见,智慧交锋。现将其真知灼见整理摘要与读者分享,以期待更多学者共同关注当前经济发展方式转变进程中的财税政策

半球型锥齿轮建模与柔体动力学分析

为了探究半球型锥齿轮参数变化对其系统动态特性的影响，基于集中质量法建立了该半球型锥齿轮副的动力学模型；基于高质量的六面体网格模型，采用刚柔耦合柔体动力学仿真分析了半球型锥齿轮的动态传动性能；分析了半球型锥齿轮尺寸、轴交角等参数变化对系统运动状态的影响。仿真结果表明，系统在不同参数条件下会导致传动准确性、平稳性和强度有规律的变化且互为负相关；半球型锥齿轮在分度圆直径为65 mm、相交轴角度为120°时综合性能最优。柔体动力学仿真分析为研究半球型锥齿轮的设计、制造以及实现齿轮传动最优化，提供了重要的参考价值

主轴承径向轴颈型线对润滑状态的影响

以某型柴油机主轴承为研究对象，计入主轴承表面粗糙度和弹性变形等因素，建立主轴承润滑状态的分析模型，分析了主轴承径向轴颈型线对润滑状态的影响。结果表明，与不考虑径向轴颈型线的计算结果相比，计入径向轴颈型线时，主轴承的最小油膜厚度增加了25.95%，最大油膜压力减小了17.69%，平均摩擦损失减小了6.14%，主轴颈倾斜现象有所改善。随着轴颈表面粗糙度的增加，主轴承的最小油膜厚度增加，最大油膜压力几乎不变，平均摩擦损失增加