Recycling of the hyperaccumulator Brassica juncea L.: synthesis of carbon nanotube-Cu/ZnO nanocomposites

The methods of synthesizing carbon nanotube (CNTs)-Cu/ZnO nanocomposites using a Cu hyperaccumulator (Brassica juncea L.) constitute a new insight into the recycling of hyperaccumulators and provide a new route for the further development of green nanostructure syntheses. In this paper, CNTs-Cu/ZnO nanocomposites have been synthesized using B. juncea plants as the sources of C, Cu, and Zn. The synthesized CNTs-Cu/ZnO nanocomposites were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), and energy dispersive spectra (EDS). The synthesized CNTs were characterized further by selected area diffraction (SAD) patterns and Raman spectroscopy. The results demonstrated that the structure of individual CNTs was middle-hollow, with an outer diameter of about 80 nm. The synthesized CNTs were not at all crystalline and there were a few defects in the walls. The outer diameter of CNTs-Cu/ZnO nanocomposites was 110 nm. The diameters of Cu/ZnO nanoparticles were 29.5/32.7 nm, respectively. Cu/ZnO nanoparticles that had grown onto the CNT surface were nonuniform and agglomerated. The Cu/ZnO nanoparticles were pure.     

Population Growth,Available Resources,and Quality of Life:China’s Post-Reform Economic Development

Two opposing intellectual traditions and their contem-porary developments regarding the relations among population, available resources, and quality of life as reflected in economic growth are reviewed. What is at issue is whether population growth is detrimental to or beneficial for economic development. Neither of the extreme views gives a complete picture of the interplay among population, resources, and quality of life. Following previous literature on the topic, this paper establishes a more balanced approach that considers the function linking population and quality of life not constant but variable and regards the limitedness of resources as not absolute but relative to regions and societies. The proposed approach is more flexible in better explaining the relation between population and economic growth. China is examined as a case in point to shed light on the interaction of population growth, economic development, and available resources, and its recent post-economic reform experiences showcase the appropriateness of the synthetic approach.     

Controllable synthesis Fe3O4@POHABA core-shell nanostructure as high-performance recyclable bifunctional magnetic antimicrobial agent

We demonstrated a method to form magnetic antimicrobial POHABA (poly-N,N′-[(4,5-dihydroxy-1,2-phenylene)bis(methylene)]bisacrylamide)-based core-shell nanostructure by free-radical polymerization of OHABA on the Fe₃O₄ core surface. The magnetic antimicrobial agent Fe₃O₄@POHABA can be used in domestic water treatment against bacterial pathogens. The thickness of POHABA shell could be controlled from 10.4 ± 1.2 to 56.3 ± 11.7 nm by the dosage of OHABA. The results of antimicrobial-activity test indicated that POHABA-based core-shell nanostructure had broad-spectrum inhibitory against Gram-negative, Gram-positive bacteria and fungi. The minimum inhibitory concentration (MIC) values of Fe₃O₄@POHABA nanostructure against Escherichia coli and Bacillus subtilis were both 0.4 mg/mL. Fe₃O₄@POHABA nanostructures responded to a permanent magnet and were easily recycled. Fe₃O₄@POHABA nanoparticles retained 100% antimicrobial efficiency for both Gram-negative and Gram-positive bacteria throughout eight recycle procedures.

     

Eukaryotic community diversity and pathogenic eukaryotes in a full-scale drinking water treatment plant determined by 18S rRNA and metagenomic sequencing

Environmental Science and Pollution Research - In this study, 18S rRNA high-throughput sequencing was applied to investigate the eukaryotic community in a full-scale drinking water treatment plant....     

Effects of river-lake interactions in water and sediment on phosphorus in Dongting Lake,China

Environmental Science and Pollution Research - As a large river connected lake, Dongting Lake is influenced by anthropogenic activities and the discharge from its upstream tributaries in the lake...     

长江上游流域大洪水天气分型特征分析

通过对1981~2012年24例长江上游流域大洪水过程进行普查,发现影响长江上游大洪水强降水过程的天气系统主要为:巴湖槽东移型、贝湖槽稳定型和东北冷槽型。采用统计、诊断及合成分析方法,对3种不同天气类型的大尺度环流背景、主要影响系统及致洪降水发生机理进行研究,并总结其特点及差异。结果表明:3种类型大洪水的洪水特征及降水特征各不相同,大尺度环流背景及天气系统也有所差异。副高及500hPa中高纬环流形势异常是导致强降水发生的直接因素,西南涡、冷暖式切变线及冷空气在不同的类型洪水降水中作用各不相同,异常气旋性环流场、水汽输送方向及水汽通量辐合区与强降水的位置密切相关。     

江苏省乡村性空间格局及影响因素研究

基于城乡一体化思想,在分析乡村性内涵基础上,采用人口密度等指标构建乡村性评价体系,以全国第五、六次人口普查等数据为基础,借助SPSS、ArcGIS、Geoda软件,探讨了江苏省县域单元乡村性空间格局及影响因素。结果表明：(1)2000～2010年,江苏全省县域单元乡村性逐渐减弱,并呈现出阶梯状的空间分布态势;(2)各县域乡村性指数并不表现为完全随机状态,而是存在显著的正空间相关性。热点区域分布在沭阳县与泗阳县交界处为核心的圈层结构,冷点区域集中在乡镇工业发达的苏锡常地区;（3）社会环境、交通、资本、工业化和城市化、政策等因素是乡村性变化的主要影响因素;（4）未发现乡村性加强的现象;在数据可获得情况下,以乡镇为单元研究乡村性将具有更强的现实指导意义     

中国推进生态文明建设的研究进展

中国正在进入大力推进生态文明建设的新时期。基于文献统计和分析,对生态文明建设的理论基础、实践模式、突破领域、制度保障、实现机制和评价体系等方面的研究进行了述评,并提出未来研究方向和重点,展现了我国生态文明建设的认识演进、实践成效、现实问题和发展趋势。已有研究为把握生态文明的本质规律,树立生态文明价值理念,促进生产生活方式绿色转型,提供了理论基础和有益指导。但是,还存在着研究比较分散、深度不够、创新性工作缺乏、方法单一等问题。新时期大力推进生态文明建设,迫切需要综合多维度研究的成果和方法,加强研究的系统性,重构和创新理论范式和分析框架,开展实践调查和案例分析,并将"五位一体"下生态文明建设的道路选择、制度建设、评价标准等方面的研究推向深入。     

塑胶跑道中有机磷酸酯的含量及健康风险

采用超声萃取-层析净化-气相色谱/质谱联用仪定量分析塑胶跑道中7种有机磷酸酯(OPEs),方法回收率为71.41%~110.58%,标准曲线相关系数r0.99,质控良好.采集并分析了成都市12个学校内的塑胶跑道样品中OPEs的含量及分布.结果表明2/3学校内的塑胶跑道样品中检出了OPEs,其中磷酸三正丁酯[tri-n-butyl phosphate,TnBP]、磷酸三异辛酯[tris(2-ethylhexyl)phosphate,TEHP]的检出率较高,而磷酸三(2-氯乙基)酯[tri(2-chloroethyl)phosphate,TCEP]、磷酸三(1,3-二氯异丙基)酯[tridichloropropyl phosphate,TDCPP]、磷酸三苯酯[triphenyl Phosphate,TPh P]在所有样品中均未检测到.Σ7OPEs含量范围为ND~534.89 ng·g~(-1),其中单体含量最高的是TnBP(ND~462.18 ng·g~(-1)).一个样品中检出了毒性较大的氯代磷酸酯-TCPP[trichloropropyl phosphate],含量为205.94 ng·g~(-1).成人和儿童通过皮肤接触摄入的Σ7OPEs日均暴露剂量(以bw计)最高,分别为0.14 ng·(kg·d)~(-1)和0.64 ng·(kg·d)~(-1),儿童的日均暴露剂量明显高于成人.成人及儿童的风险熵值(RQ)为10~(-7)~10~(-5).建议政府对塑胶跑道中OPEs使用量及添加种类进行管控,以更好地保护人群健康.     

巢湖湖滨带植被特征及其退化原因分析研究

于2009年和2010年对巢湖湖滨带植被进行了详细踏查,结果表明:(1)植被群落结构单一,多样性较差,大都集中分布于浅水、河口、滩地,受水质和水位影响显著;(2)挺水植物有5科6属6种,以芦苇(Phrag-mites australis)为优势种;(3)浮叶植物3科3属3种;以野菱(Trapa incisa)和荇菜(Nymphoides peltatum)为优势种;(4)漂浮植物2科2属2种;主要是凤眼莲(Eichhornia crassipes)和浮萍(Lemna minor);(5)沉水植物4科5属8种;以马来眼子菜(Potamogeton malaianus)为优势种;(6)湿生和陆生植物27科76属101种;以禾本科为主,菊科、蓼科植物次之。调查结果与历史资料(1954年-2007年)对比,得出巢湖流域土地利用格局、江湖建闸等水利工程、围湖造田与堤坝建设等人为活动以及富营养化与蓝藻水华等综合因素严重破坏了巢湖湖滨带健康的生态系统,加剧了湖滨带植被的衰退。本研究可为巢湖湖滨带植被的恢复提供理论指导。