The effect of γ-Fe2O3 nanoparticles on Escherichia coli genome

Extensive production and application of γ-Fe₂O₃ magnetic nanoparticles (MNPs) has increased their potential risk on environment and human health. This report illustrates a genetic impact of γ-Fe₂O₃ magnetic nanoparticles (MNPs) on Escherichia coli (E. coli). After 3000-generation incubation with MNPs addition, obvious genomic variations were revealed by using repetitive extragenic palindromic PCR (rep-PCR) DNA fingerprint technique. The physicochemical interactions between MNPs and bacteria could be responsible for such genomic responses. It was revealed that Fe³⁺ concentration increased in the medium. Transmission electronic microscopy (TEM) and flow cytometry (FCM) analysis consistently demonstrated the occurrences of adsorption and membranes-internalization of MNPs outside and inside cells. Both increased Fe³⁺ ion and the uptake of MNPs facilitated Fe binding with proteins and DNA strands, resulting in enhancing the mutation frequency of E. coli. Our results would be of great help to assessing the potential impact of MNPs on human and environment.     

环境水体中四溴双酚A的HPLC-MS/MS分析方法的建立与应用

四溴双酚A(tetrabromobisphenol A,TBBPA)是目前使用量最大的溴代阻燃剂.随着它的广泛应用,已经引起了大气、水体、沉积物和土壤等环境介质及相关生态系统的严重污染.建立了环境水体中TBBPA的高效液相色谱-串联质谱(HPLC-MS/MS)分析方法.该方法采用电喷雾电离(ESI)负离子模式进行扫描,...     

新型混凝剂聚磷氯化铝铁的表征及应用

以FeCl3·6H2O、AlCl3·6H2O和Na2HPO4·12H2O为主要原料,采用共聚工艺,制备了聚磷氯化铝铁(PPAFC)混凝剂.采用FTIR及SEM进行结构表征,推断磷酸根为与聚合氯化铝铁(PAFC)接聚,而不是磷酸盐与PAFC之间简单的物理混合.实验结果表明,以PPAFC处理含油乳化液废水、造纸废水及受污染...     

Developmental toxicity of cypermethrin in embryo-larval stages of zebrafish

Cypermethrin, a type II pyrethroid insecticide, is widely used throughout the world in agriculture, forestry, horticulture and homes. Though the neurotoxicity of cypermethrin has been thoroughly studied in adult rodents, little is so far available regarding the developmental toxicity of cypermethrin to fish in early life stages. To explore the potential developmental toxicity of cypermethrin, 4-h post-fertilization (hpf) zebrafish embryos were exposed to various concentrations of cypermethrin (0, 25, 50, 100, 200 and 400 μg L⁻¹) until 96 h. Among a suite of morphological abnormalities, the unique phenotype curvature was observed at concentrations as low as 25 μg L⁻¹. Studies revealed that 400 μg L⁻¹ cypermethrin significantly increased malondialdehyde production. In addition, activity of antioxidative enzymes including superoxide dismutase and catalase were significantly induced in zebrafish larvae in a concentration-dependent manner. To further investigate the toxic effects of cypermethrin on fish, acridine orange (AO) staining was performed at 400 μg L⁻¹ cypermethrin and the result showed notable signs of apoptosis mainly in the nervous system. Cypermethrin also down-regulated ogg1 and increased p53 gene expression as well as the caspase-3 activity. Our results demonstrate that cypermethrin was able to induce oxidative stress and produce apoptosis through the involvement of caspases in zebrafish embryos. In this study, we investigated the developmental toxicity of cypermethrin using zebrafish embryos, which could be helpful in fully understanding the potential mechanisms of cypermethrin exposure during embryogenesis and also suggested that zebrafish could serve as an ideal model for studying developmental toxicity of environmental contaminants.     

Free atmospheric phosphine concentrations and fluxes in different wetland ecosystems, China

Atmospheric phosphine (PH₃) fluxes from typical types of wetlands and PH₃ concentrations in adjacent atmospheric air were measured. The seasonal distribution of PH₃ in marsh and paddy fields were observed. Positive PH₃ fluxes are significantly related to high air temperature (summer season) and increased vegetation. It is concluded that vegetation speeds up the liberation of PH₃ from soils, while water coverage might function as a diffusion barrier from soils or sediments to the atmosphere. The concentrations of atmospheric PH₃ (ng m⁻³) above different wetlands decrease in the order of paddy fields (51.8 ± 3.1) > marsh (46.5 ± 20.5) > lake (37.0 ± 22.7) > coastal wetland (1.71 ± 0.73). Highest atmospheric PH₃ levels in marsh are found in summer. In paddy fields, atmospheric PH₃ concentrations in flourishing stages are higher than those in slowly growing stages.     

Comparison of initial hydrolysis of the three dimethyl phthalate esters (DMPEs) by a basidiomycetous yeast,Trichosporon DMI-5-1, from coastal sediment

Purpose  

Dimethyl phthalate esters (DMPEs) are a group of plasticizers commonly detected in the environment with potential adverse human health impact. The degradation of DMPEs by fungal systems has been studied to a limited extent, particularly by yeasts. In this study, a basidiomycetous yeast Trichosporon DMI-5-1 capable of degrading DMPEs was obtained and the degradation pathways were investigated.     

环境中三甲胺的气相色谱测定

采用ＰＥＧ２０Ｍ３０ｍ×５３０μｍ弹性石英毛细管色谱柱分离,ＦＩＤ检测器检测。环境空气用水吸收,水样直接或顶空进样测定环境中的三甲胺。方法有较高的灵敏度和良好的线性关系,简便快速。     

改进抽油机井“功率平衡”测试实现节能降耗

目前在抽油机井管理中普遍采用的平衡标准是"电流平衡",并认定电流平衡度在80%～120%之间时抽油机即为平衡。而真正判断抽油机平衡的标准是"功率平衡",即抽油机运行过程中,下冲程内电机平均功率与上冲程内电机平均功率相等。抽油机功率平衡既能实现节能目的,又能保证抽油机安全运行。从2008年7月开始率先在胜利油田进行抽油机功率平衡技术的试验及推广,2008年共调整抽油机功率平衡118井次,平均单日节电21.4kW.h,平均节电率9.90%,取得了良好的节能效果。     

SBR工艺数学模型研究进展及其应用

SBR法具有操作简单、运行方式灵活、占地面积小等优点,用于处理间歇排放的工业废水及中小城镇污水取得了巨大成功,并在全世界范围内迅速得到发展和推广应用。随着自控技术的飞速发展和对SBR工艺机理的深入认识,围绕SBR工艺数学模型的研究引起各国学者的重视。回顾了目前SBR法数学模型的研究进展和应用现状,并总结和比较了各种数学模型的优势和不足,特别是对机理模型（白箱模型）和统计模型（黑箱模型）进行了分类、归纳和分析。所有这些数学模型建模与仿真的目的都是为了实现SBR工艺优化控制,为实际SBR污水处理厂的运行提供依据和技术支持。虽然以前的研究有力地推动了数学模型在SBR工艺中的应用,但是在实际应用中还存在很多值得深入研究的问题。最后对SBR工艺数学模型尚待解决的问题进行了总结,并指出今后SBR数学模型的发展方向。     

The Economic Effect of Mineral Resources Exploitation in Bijie Prefecture in Guizhou

The exploitation of mineral resources plays an important role in promoting national economic development. Mining is an essential component of China＇s industrial economy. Using grey correlation method to analyze the correlative effect of mineral resources exploitation to relevant industries, using national income method to calculate the pulling effect of mineral resources exploitation to economic growth and using graphs as well as tables to analyze the income distribution effect, the article obtains active economic effect of mineral resources development in Bijie, Guizhou. Moreover, from the view of resources-cored effect, the article analyzes negative effects such as single industrial structure brought by mineral resource development. Through analysis, we find that mineral resources exploitation to some extent brings active effects including gross domestic product growth, local financial revenue growth and relevant industries development; however, its negative effects should not be ignored. The negative effect can be lightened by diversifying industrial structure and prolonging industrial chain.