四环素胁迫对Shigella flexneri细菌四环素抗性基因抗性表达的影响过程

四环素(TC)抗生素在不同环境介质中已被广泛检出,为研究其对四环素抗性基因(TC-ARGs)丰度变化及表达水平的影响过程,以从活性污泥中筛选和纯化分离获得的弗氏志贺氏菌(Shigella flexneri)为研究对象,考察了不同浓度TC对其生长过程的作用影响,采用荧光定量PCR和逆转录PCR方法定量检测了不同抗性机制TC-ARGs,包括tetC、tetO和tetX基因的丰度变化及表达水平,并探讨了TC浓度与TC-ARGs丰度及其表达水平之间的相关关系.结果表明,在培养周期内(24 h),TC胁迫对Shigella flexneri细菌的生长具有抑制作用,细菌细胞浓度增长速率随TC暴露浓度的升高而降低,但对TC-ARGs丰度变化影响较小.TC胁迫能够促进Shigella flexneri细菌TC-ARGs的转录表达,tetC、tetO和tetX基因表达水平在整个培养周期内均先升高后降低.由相关性分析可知,TC浓度与TC-ARGs丰度及其表达水平之间相关关系不显著,但tetC和tetO基因丰度与其转录表达水平之间存在显著的正相关关系,表明其基因丰度一定程度上可用来衡量和评价其抗性表达水平.     

餐饮废水处理技术探讨

介绍了我国餐饮业的发展趋势，指出餐饮废水已经成为城市的主要高浓度污染源之一，同时适当地讨论了目前餐饮废水处理技术研究的现状以及处理系统的技术要求，最后提出了对不同规模的餐饮废水处理的适当方法。     

旋流器在船舶舱底含油污水分离中的应用

分析了船舶舱底含油污水的特性，讨论了船舶油水分离器的现状及使用中存在的问题，提出了使用旋流器对船舶舱底含油污水进行预处理，以改善进入船舶油水分离器的水质及减轻管理人员负担。     

膜生物反应器处理印染废水的研究进展

印染废水是一种有机物含量高、色度深、生化性差、难降解的工业废水,采用传统的污水处理工艺很难达到排放标准,对新型、高效的处理工艺的研究越来越受到人们的关注.膜生物反应器是一种新型水处理技术,具有传统废水处理工艺所无法比拟的优势,通过膜生物反应器处理后的印染废水,甚至达到了回用水标准,在此基础上对现在研究较多的膜生物反应器的改进技术进行了综述并指出了还有待解决的问题,为将来的发展提供参考和依据.     

Recent patterns of production for the main cereal grains: implications for food security in China

China’s large population and deteriorating environment have created great concern related to the sustainability of food production, especially since details related to this topic remain poorly studied. Thus, an integrated analysis of both crop yield and cultivated area is essential for gaining a better understanding of cereal grain production in China and for making corresponding policies designed to achieve food security. In this study, we adopt trend analysis of both provincial yield and cultivated area to assess the subsequent provincial-level cereal production sustainability between 1980 and 2011 with the goal of providing a better understanding of regional agricultural development. The results indicate that while maize shows the most promise for yield improvement, rice and wheat production is experiencing substantial yield stagnation among most provinces across mainland China. In addition, the trends in spatial patterns are prominently different from those of yields. The sizes of the main rice- and wheat-growing areas in China have declined greatly, suggesting that the related production of these cereals should attract more attention from land management planners and farmers. Specifically, the south-eastern coastal provinces have largely failed to sustain both crop yield and area, while the north-eastern provinces have witnessed thriving agricultural production during the last three decades. Moreover, we find that cereal production in China is significantly affected by governmental policies related to the agricultural sector. Thus, this analysis of food production in China will help policymakers to better understand how the potential implications of food security in China may be applicable to countries worldwide.     

Efficacy of created and restored nesting sites for the conservation of colonial Laridae in the South of France

By rapidly modifying key habitat components, habitat restoration is at risk of producing attractive cues for animals without providing habitats of sufficient quality. As such, individual fitness components, such as reproduction, could be reduced and restored habitats could become ecological traps. This risk notably appears by using artificial constructions in restoration projects, yet few studies have evaluated their efficacy in a robust way. We investigated this by analyzing 154 islets that were created or restored to improve the conservation status of 7 colonial Laridae species in the South of France. From 2007 to 2016, we compared occupancy dynamics and breeding parameters of these species between the restored sites and 846 unmanaged nesting sites. We also explored species’ preference for different nesting site characteristics and their respective effect on breeding parameters. Restored nesting sites were 2–9 times as attractive as unmanaged sites for all species except the Black-headed Gull (Chroicocephalus ridibundus). Colonization probability was up to 100 times higher in sites already used by other species the previous year and increased with distance to the shore until >0.2 when distance was over 250 m. Abandonment probability was 29–70% lower when breeding was successful the previous year in all species except the Sandwich Tern (Thalasseus sandvicensis). Productivity and breeding success probability were 2 times higher on managed sites. Distance from the shore was an important attractive characteristic of artificial nesting sites in all species. Other nesting site characteristics had species-specific effects on colonization, abandonment, and breeding success. Our results indicate that managed nesting sites are successful conservation tools for colonial Laridae in the Mediterranean and do not act as ecological traps. Our study showed that testing the ecological trap hypothesis is a robust way to evaluate the success of restoration projects of breeding habitats.     

自适应智能电磁防护材料测试方法研究

目的在强电磁场环境下研究自适应智能电磁防护材料的相变特性。方法针对自适应智能电磁防护材料相变前后电导率的变化范围大、需要强场激励状况,考虑测试系统强场生成、大动态范围、测试精度以及相应的绝缘性和较高的安全性要求,采用电容充放电原理设计强场激励测试电路,搭建绝缘环境,确保操作的安全性和测试数据的可靠性。结果利用测试系统对现有商业化电阻器进行验证试验,得到的特性曲线与理论相一致。结论测试系统能够满足自适应智能电磁防护材料相变特性试验的需求,可获取有效且可靠的测试数据。     

基于物理过程的矿区地下水污染风险评价

目前国内外所做的地下水污染风险评价的实例研究一般都是从地下水的脆弱性研究出发,并未过多地考虑特征污染物对污染后果的影响.脆弱性是环境对污染物的自然敏感性,而地下水污染评价中更应当体现出污染物在地下水中的迁移分布特性.为了完善地下水污染风险评价的理论和方法,以某尾矿区为例提出了基于物理过程的地下水污染风险评价方法,在污染发生之前,根据经济社会的敏感性条件和污染物将来可能的分布范围,事先划分各个污染风险等级在含水层空间上的分布范围,然后据此反推各个风险等级所对应的污染物源强,以此作为地下水污染风险评价等级的划分标准,通过对污染物在包气带和含水层中的运移进行数值模拟来评价尾矿区地下水的污染风险.结果表明,这种基于物理过程的地下水污染风险评价方法可以给出污染物浓度和风险水平在空间和时间上的分布规律,对于单个点状的污染场地来说,具有详尽的风险表征方式,优于以往基于含水层固有脆弱性指数法的风险评价方法,该方法适用于现有污染场地的风险评价、场地优化选址和为场地建设提供设计参数.     

污水处理厂中红霉素抗药性基因的污染特征及选择性因子

采用固相萃取-高效液相色谱串联质谱(SPE-HPLC-MS/MS)检测分析了上海某污水处理厂中12种不同药品和个人护理品(pharmaceutical and personal care products,PPCPs)的含量水平和分布特征,采用实时荧光定量PCR方法定量检测分析了7种红霉素抗药性基因(ERY-ARGs)在污水处理厂中的分布和丰度变化.结果表明,在污水处理厂中共检出5种PPCPs(包括磺胺甲唑、红霉素、四环素、卡马西平和三氯生),浓度范围分别为24.5~38.7、47.5~49.2、43.1~85.4、2.5~3.9和423.2~8 973.3ng·L-1.两段A/O生物处理工艺对三氯生具有较好的去除效果,但对其余4种PPCPs的去除效果较差.与此同时,目标ERY-ARGs在污水处理厂中均被检出,在原水中的丰度达9.28×103(erm A)~1.83×108(ere A)copies·L-1,虽然两段A/O工艺能够显著降低污水中的ERY-ARGs(1.19 log~3.97 log),但其在最终处理出水中的浓度仍然较高.通过相关性分析可知,ERY-ARGs与红霉素和三氯生之间均具有显著相关性(P<0.05),表明污水处理厂中红霉素对ERY-ARGs的产生和传播具有重要影响,而三氯生对ERY-ARGs可能存在交叉选择性作用.