Growth response of Zea mays L. in pyrene-copper co-contaminated soil and the fate of pollutants

Phytoremediation, use of plants for remediation, is an emerging technology for treating heavy metals or a final polishing step for the high-level organic contamination, and may be suitable for remediation of heavy metal and organic co-contaminated soil. The aim of this study was to investigate the influence of co-contamination on the growth of Zea mays L. and the fate of both heavy metal and organic pollutants, using Cu and pyrene as the model pollutants. Results showed that shoot and root biomass were affected by the copper–pyrene co-contamination, although maize grown in spiked soils showed no outward signs of phytotoxicity. With the initial concentration of 50,100 and 500 mg/kg, pyrene tended to alleviate the inhibition of Cu to Z. mays L. Pyrene in both planted and non-planted soil was greatly decreased at the end of the 4-week culture, accounting for 16–18% of initial extractable concentrations in non-planted soil and 9–14% in planted soil, which indicated that the dissipation of soil pyrene was enhanced in the presence of vegetation probably due to the biodegradation and association with the soil matrix. With the increment of Cu level, residual pyrene in the planted soil tended to increase. The pyrene residual in the presence of high concentration of Cu was even higher in the planted soil than that in the non-planted soil, which suggested that the change of the microbial composition and microbial activity or the modified root physiology under Cu stress was probably unbeneficial to the dissipation of pyrene. A more thorough understanding of the mechanisms by which metals affect the dissipation of organic pollutants in the rhizosphere could provide a much better framework on which to base manipulation. Unlike pyrene, heavy metal copper cannot be degraded. Decontamination of Cu from contaminated soils in this system required the removal of Cu by plants. It was observed that the ability of Cu phytoextraction would be inhibited under co-contamination of high level of pyrene in highly Cu-polluted soil. In the treatment of 400 mg Cu/kg and 500 mg pyrene/kg, the accumulation of Cu was less than half of that in 400 mg Cu/kg treatment.     

Microstructural Evolution of Al-1Fe (Weight Percent) Alloy During Accumulative Continuous Extrusion Forming

As a new microstructure refining method, accumulative continuous extrusion forming (ACEF) cannot only refine metal matrix but also refine the phases that exist in it. In order to detect the refinements of grain and second phase during the process, Al-1Fe (wt pct) alloy was processed by ACEF, and the microstructural evolution was analyzed by electron backscatter diffraction (EBSD) and transmission electron microscopy (TEM). Results revealed that the average grain size of Al-1Fe (wt pct) alloy decreased from 13 to 1.2 μm, and blocky Al₃Fe phase with an average length of 300 nm was granulated to Al₃Fe particle with an average diameter of 200 nm, after one pass of ACEF. Refinement of grain was attributed to continuous dynamic recrystallization (CDRX), and the granulation of Al₃Fe phase included the spheroidization resulting from deformation heat and the fragmentation caused by the coupling effects of strain and thermal effect. The spheroidization worked in almost the entire deformation process, while the fragmentation required strain accumulation. However, fragmentation contributed more than spheroidization. Al₃Fe particle stimulated the formation of substructure and retarded the migration of recrystallized grain boundary, but the effect of Al₃Fe phase on refinement of grain could only be determined by the contrastive investigation of Al-1Fe (wt pct) alloy and pure Al.     

2017年广东省海产品中致病菌检测能力验证结果与分析

目的了解广东省食品检测实验室的致病菌检测能力和水平,提高海产品中致病菌的检测能力,促进实验室检测能力的提高。方法参照GB/T4789.20-2003、GB4789.30-2010等相关标准方法中的要求,分别对样品进行定性检测与鉴定。结果此次考核共发放7类(种)样品, A样品(福氏志贺氏菌)、B样品(副溶血性弧菌)、C样品(金黄色葡萄球菌与副溶血性弧菌混合菌)、D样品(致病性大肠埃希氏菌)、E样品(单核细胞增生李斯特氏菌)、F样品(福氏志贺氏菌与单核细胞增生李斯特氏菌混合样)和G样品(无菌),以上样品的检测满意率分别为100%(5/5)、 97.1%(34/35)、 94.3%(33/35)、 64.7%(11/17)、 100%(35/35)、 92.9%(13/14)和97.1%(34/35)。总满意率为71.4%(25/35),其中疾控系统满意度为77.4%(24/31)。结论参加此次考核的单位大部分都取得了满意的结果,特别是承担食品安全风险监测微生物检测实验室,存在的最大问题是关于致病性大肠埃希氏菌(EPEC)的检测,有1/3的实验室未能正确检出,提示要提高全省关于海产品中食源性致病菌的整体检出水平,相关实验室要加强质量控制管理,尤其是EPEC的检测能力需要提高。     

Eu3+掺杂硼酸盐玻璃的发光性质及其热稳定性研究

荧光玻璃具有发光中心分布均匀和热稳定好等优点, 成为LED领域研究的热点。本研究采用传统的高温熔融淬火法合成了一系列Eu³⁺掺杂的硼酸盐玻璃, 通过荧光光谱手段对其发光性质及热稳定性进行了表征; 利用Van Uitert模型对样品中Eu³⁺的浓度猝灭行为进行了研究。结果表明: 样品中Eu³⁺的浓度猝灭机理为Eu³⁺离子间的交换作用导致的无辐射能量传递; 利用Arrhenius公式对荧光玻璃样品的温度猝灭行为进行了分析。结果表明: 样品中Eu³⁺的发光温度猝灭属于Crossover过程; 最后分析了Eu³⁺与荧光玻璃基质之间的相互作用。     

One-step synthesis,electromagnetic and microwave absorbing properties of α-FeOOH/polypyrrole nanocomposites

One-step synthesis of α-FeOOH/polypyrrole (PPy) nanocomposites is reported for the first time via a facile one-step chemical method in the presence of OH⁻, Fe²⁺, Fe³⁺ and pyrrole monomer. α-FeOOH nanorods are in situ formed in PPy matrix and the content of α-FeOOH nanorods increases with decreasing the molar ratio of pyrrole to Fe²⁺ ([Py]/[Fe²⁺] ratio). The electromagnetic and microwave absorbing properties of the nanocomposites are investigated as a function of the [Py]/[Fe²⁺] ratio. The results show that the PPy nanocomposites exhibit good conductivity (up to 16.10 S/cm) and antiferromagnetic behavior. The reflection loss evaluation based on the absorbing wall theory at the thickness of 2 mm shows that the nanocomposite at [Py]/[Fe²⁺] = 1.0 exhibits the best microwave absorbing property in the 2–18 GHz. And the corresponding reflection frequency range under −10 dB and −5 dB is 4.2 GHz and 5.8 GHz, respectively.     

6种金枪鱼脂肪酸组成与含量差异性研究

目的比较捕捞于不同海域不同品种的6种金枪鱼的脂肪酸种类与含量。方法收集来源于大西洋、太平洋、印度洋的蓝鳍金枪鱼(Thunnus thynnus)、黄鳍金枪鱼(Thunnus albacores)、大目金枪鱼(Thunnus obesus)、马苏金枪鱼(Thunnus maccoyii)、长鳍金枪鱼(Thunnus alalunga)、鲣鱼(Katsuwonus pelamis)6种金枪鱼,采用三氟化硼甲醇甲酯化金枪鱼肌肉组织的脂肪酸,利用气相色谱法测定脂肪酸甲酯含量;再通过SPSS 24对各脂肪酸组成结果进行相关性分析。结果 6种金枪鱼肌肉脂肪酸种类与含量丰富,蓝鳍金枪鱼、大目金枪鱼等5种金枪鱼不饱和脂肪酸的含量明显高于鲣鱼,蓝鳍金枪鱼的不饱和脂肪酸种类最多且含量最高,捕捞于太平洋海域的大目金枪鱼、黄鳍金枪鱼的不饱和脂肪酸种类明显多于其他海域,人工饲养的马苏金枪鱼(太平洋)比野生马苏金枪鱼(印度洋)的不饱和脂肪酸种类丰富;6种金枪鱼主要组分间的相关性分析结果显示,C20:0与所测的9种脂肪酸呈负相关,C18:1与C18:2呈极显著正相关(r=0.900～1.000),C14:0与C17:1呈负相关,与其他8种脂肪酸呈正相关。结论 6种金枪鱼存在脂肪酸种类与含量的差异,不同海域与不同养殖方式下的金枪鱼脂肪酸的种类也存在差异。     

淀粉蔗糖酶的研究进展

介绍了一种新型淀粉蔗糖酶（AS）的国内外研究状况以及其功能特性与结构特征,总结了淀粉蔗糖酶三维空间结构和合成聚合物的机制,以及在理论和实际应用中的价值和意义,并对淀粉蔗糖酶今后的研究和应用进行了展望。     

基于适配体生物传感器检测黄曲霉毒素B1的研究进展

随着生活水平的提高, 人们对生命健康格外注重, 而由生物毒素引起的食物中毒的悲剧却频繁发生, 因此得到了社会的广泛关注。简便快速、特异性高、易携式的生物毒素检测仪器成为研究人员研究的热点。适配体(aptamer)作为一种新型识别分子, 具有亲和力高、稳定性强、制备成本低、特异性强等明显优势, 已成功应用于食品中有害物质的识别检测。随着色谱技术、免疫化学以及光、电等领域的不断发展, 将适配体与靶物质的特异性识别结合过程转换为易于检测的物理化学信号, 能够实现灵敏度高、微型化、高通量和现场检测的快速分析。本文主要从试纸条法、荧光、电化学传感器等方面以黄曲霉毒素B1(aflatoxin B1, AFB1)为靶标的适配体在食品安全检测分析中的应用进行了综述, 以期为进一步研究提供参考。     

Beautified QR code with high storage capacity using sequential module modulation

Multimedia Tools and Applications - For the issue of beautification and capacity expansion of the Quick Response(QR) code, we proposed an algorithm based on sequential module modulation. First, the...     

基于UML活动图的测试研究进展

UML活动图不再是状态图的特例,它作为一种独立的模型广泛用于软件的行为建模.基于UML活动图的测试受到业界的普遍欢迎.然而从UML活动图自动生成完整的测试场景\用例成为一个难点.本文对基于UML活动图的测试进行了比较分析,总结了几种从UML活动图生成测试场景\用例的方法及其使用的算法,即反蚂蚁Agent方法、灰盒方法、自适应细菌Agent方法和系统的形式化方法.对这些方法进行了分析与比较,指出一些不足之处.最后对UML活动图测试的发展趋势做了一些展望.