Difference in calcium ion precipitation between free and immobilized Halovibrio mesolongii HMY2

Biomineralization has become a research focus in wastewater treatment due to its much lower costs compared to traditional methods. However, the low sodium chloride (NaCl)-tolerance of bacteria limits applications to only water with low NaCl concentrations. Here, calcium ions in hypersaline wastewater (10% NaCl) were precipitated by free and immobilized Halovibrio mesolongii HMY2 bacteria and the differences between them were determined. The results show that calcium ions can be transformed into several types of calcium carbonate with a range of morphologies, abundant organic functional groups (C-H, C-O-C, C=O, etc), protein secondary structures (β-sheet, α-helix, 3₁₀ helix, and β-turn), P=O and S-H indicated by P2p and S2p, and more negative δ¹³C_PDB (‰) values (-16.8‰ to -18.4‰). The optimal conditions for the immobilized bacteria were determined by doing experiments with six factors and five levels and using response surface method. Under the action of two groups of immobilized bacteria prepared under the optimal conditions, by the 10^th day, Ca²⁺ ion precipitation ratios had increased to 79%-89% and 80%-88% with changes in magnesium ion cencentrations. Magnesium ions can significantly inhibit the calcium ion precipitation, and this inhibitory effect can be decreased under the action of immobilized bacteria. Minerals induced by immobilized bacteria always aggregated together, had higher contents of Mg, P, and S, lower stable carbon isotope values and less well-developed protein secondary structures. This study demonstrates an economic and eco-friendly method for recycling calcium ions in hypersaline wastewater, providing an easy step in the process of desalination.     

装备外部冷却方法及在环境试验中的应用概述

首先简述了机载电子装备冷却的基本要素。其次,详细介绍了机载电子装备环控通风冷却、液体冷却方式的具体要求及不同的接口方式。然后,通过实例介绍了装备的不同冷却方式、方法及在实际中的应用。通过试验研究发现,不同的冷却方式不仅对机载电子装备本身有不同程度的影响,还对机载电子装备在环境试验过程中产生极大的影响,从而提出在实际应用中,应着重依据分析的内容考虑机载电子装备需采用的冷却方式,以达到最好的实施效果。     

Soil contamination with antibiotics in a typical peri-urban area in eastern China: Seasonal variation, risk assessment, and microbial responses

The prevalence and persistence of antibiotics in soils has become an emerging environmental issue and an increasing threat to soil security and global public health. The problem is more severe in areas undergoing rapid urbanization; however, the ecological risks of antibiotics, seasonal variability, and associated soil microbial responses in peri-urban soils have not been well-explored. The seasonal soil sampling campaigns were conducted in a typical peri-urban watershed in eastern China to investigate distribution of antibiotics. The results demonstrated higher mean concentrations of most antibiotic compounds in winter than in summer in peri-urban soils. The seasonal variations of norfloxacin, enrofloxacin, and ciprofloxacin were more significant than those of other antibiotics, due to their higher migration ability and bioavailability. An ecological risk assessment demonstrated that chlortetracycline, ciprofloxacin, doxycycline, and ofloxacin can pose high risks to soil microorganisms. Furthermore, the coexistence of multiple antibiotics obviously poses higher risks than individual compounds. A redundancy analysis demonstrated that tetracyclines mainly showed negative correlations with Firmicutes and Chloroflexi, and quinolones showed obviously negative correlations with Acidobacteria, Gemmatimonadetes, and Nitrospirae, suggesting potential inhibition from antibiotics on biological activities or biodegradation processes. However, the persistence of antibiotics in soil results in a significant decrease in bacterial diversity and a change in dominant species. Our results provide an overview of the seasonal variability of antibiotics and the associated effects on bacterial communities in peri-urban soils. The results can provide scientific guidance on decreasing soil contamination with antibiotics to enhance soil security in similar areas.     

Novel chitosan–ethylene glycol hydrogel for the removal of aqueous perfluorooctanoic acid

It is urgent to explore an effective removal method for perfluorooctanoic acid (PFOA) due to its recalcitrant nature. In this study, a novel chitosan-based hydrogel (CEGH) was prepared with a simple method using chitosan and ethylene glycol through a repeated freezing–thawing procedure. The adsorption of PFOA anions to CEGH agreed well to the Freundlich–Langmuir model with a maximum adsorption capacity as high as 1275.9?mg/g, which is higher than reported values of most adsorbents for PFOA. The adsorption was influenced by experimental conditions. Experimental results showed that the main removal mechanism was the ionic hydrogen bond interaction between carbonyl groups (COO^?) of PFOA and protonated amine (NH⁺) of the CEGH adsorbent. Therefore, CEGH is a very attractive adsorbent that can be used to remove PFOA from water in the future.     

Applications of magnetic nanoparticles in surface-enhanced Raman scattering (SERS) detection of environmental pollutants

Environmental pollution, a major problem worldwide, poses considerable threat to human health and ecological environment. Efficient and reliable detection technologies, which focus on the appearance of emerging environmental and trace pollutants, are urgently needed. Surface-enhanced Raman scattering(SERS) has become an attractive analytical tool for sensing trace targets in environmental field because of its inherent molecular fingerprint specificity and high sensitivity. In this review, we focused on the recent developments in the integration of magnetic nanoparticles(MNPs) with SERS for facilitating sensitive detection of environmental pollutants. An overview and classification of different types of MNPs for SERS detection were initially provided, enabling us to categorize the huge amount of literature that was available in the interdisciplinary research field of MNPs based SERS technology. Then, the basic working principles and applications of MNPs in SERS detection were presented. Subsequently, the detection technologies integrating MNPs with SERS that eventually were used for the detection of various environmental pollutions were reviewed. Finally, the advantages of MNP-basedSERS detection technology for environmental pollutants were concluded, and the current challenges and future outlook of this technology in practical applications were highlighted. The application of the MNPsbasedSERS techniques for environmental analysis will be significantly advanced with the great progresses of the nanotechnologies, optics, and materials.     

中国土壤污染防治管理体系思考

对中国土壤污染防治管理体系法律、法规、规范性文件及标准体系等进行了总结和分析,得出中国现行土壤污染防治管理体系存在执法依据空缺、系统性缺乏、可操作性差和协调性弱等问题.在此基础上,对中国土壤污染防治管理体系提出改善建议,如加快立法进度,土壤污染防治法需考虑与其他环境要素保护法律之间的衔接,明确各方责任,完善土壤标准体系等.尽快完善中国土壤污染防治管理体系,为中国土壤污染防治工作提供有力的法律保障.     

主观性在环境侵权案件证据和证明中的作用研究

法院在审理环境侵权案件时,往往依赖于专业鉴定、行政标准、专家意见等等客观依据来确定案件事实.但因为环境问题的复杂性,以及民事主体自身举证能力的限制,经常出现双方举证均不充分,法院无法基于现有事实和证据得出结论的情况.此时,法官应当发挥自身能动性,主动应用主观的、甚至是非科学性的因素和手段,包括容忍义务、经验法则、自由心证等等,这些因素无法被赋予客观的标准,它需要法官基于自身的理性以及经验,结合社会一般观念、习惯等因素进行判断.     

深圳冬季边界层大气中污染物垂直分布特征

为更好地掌握深圳城区近地边界层大气污染物的性质、来源及大气理化过程,2017年冬季利用深圳市356 m石岩梯度观测塔进行大气主要污染物的垂直观测,获得包括4个高度(60 m/70 m、110 m/120 m、210 m/220 m和325 m/335 m)的污染物浓度垂直分布廓线.分析了不同高度浓度的垂直廓线、相关性和日变化特征,并探讨了风向风速对其的影响.结果表明,SO_2浓度随高度升高先降低再升高,在高空存在明显的区域输送特征;NO_x、PM_(2.5)、PM_(10)浓度随高度升高而下降,70 m高度近地大气中NO_x和PM_(2.5)受局地源影响显著,白天存在由近地大气向上混合扩散的过程,而PM_(10)中的粗粒子部分在整个气层中显现出一个比较稳定的本底值;O_3浓度随高度升高而升高,主要由于夜间高空O_3缺乏NO的滴定反应而具有一个较高的背景值.     

Genomewide analysis indicates that queen larvae have lower methylation levels in the honey bee (Apis mellifera)

The honey bee is a social insect characterized by caste differentiation, by which a young larva can develop into either a queen or a worker. Despite possessing the same genome, queen and workers display marked differences in reproductive capacity, physiology, and behavior. Recent studies have shown that DNA methylation plays important roles in caste differentiation. To further explore the roles of DNA methylation in this process, we analyzed DNA methylome profiles of both queen larvae (QL) and worker larvae (WL) of different ages (2, 4, and 6 day old), by using methylated DNA immunoprecipitation-sequencing (meDIP-seq) technique. The global DNA methylation levels varied between the larvae of two castes. DNA methylation increased from 2-day- to 4-day-old QL and then decreased in 6-day-old larvae. In WL, methylation levels increased with age. The methylcytosines in both larvae were enriched in introns, followed by coding sequence (CDS) regions, CpG islands, 2 kbp downstream and upstream of genes, and 5′ and 3′ untranslated regions (UTRs). The number of differentially methylated genes (DMGs) in 2-, 4-, and 6-day-old QL and WL was 725, 3,013, and 5,049, respectively. Compared to 4- and 6-day-old WL, a large number of genes in QL were downmethylated, which were involved in many processes including development, reproduction, and metabolic regulation. In addition, some DMGs were concerned with caste differentiation.     

行为形成因子分析方法评述

为全面了解人因可靠性分析(HRA)中行为形成因子(PSF),对现有的PSF分析方法进行评述。分析情景环境的各种称谓,指出PSF是目前认可程度最高的一种,并规范PSF的定义及其内涵。分2种类型评述当前PSF的分类方法:基于影响机理分类和系统化分类。评述在HRA中PSF的选择和使用情况,针对不同的问题给出选择和使用PSF的建议。分别从定性评价和定量评价2个方面对PSF的评价方法进行评述。结果表明,PSF分析方法仍处于发展之中,需要在后续工作中不断改进。