2,3,7,8-Tetrachlorodibenzo-p-dioxin promotes migration ability of primary cultured rat astrocytes via aryl hydrocarbon receptor

Emerging evidence showed that 2,3,7,8-Tetrachlorodibenzo-p-dioxin (TCDD) could induce expression of certain reactivation-associated genes in astrocytes, however, the consequent cellular effects and molecular mechanisms are still unclear. During the process of astrocyte reactivation, migration is a critical cellular event. In the present study, we employed wound-healing assay and Transwell® motility assay to explore the effects of TCDD on cell migration in primary cultured rat cortical astrocytes. We found that upon TCDD treatments at relative low concentrations (10^? 10 and/or 10^? 9?mol/L), the ability of primary astrocytes to migrate horizontally and vertically was promoted. In line with this cellular effect, the mRNA expression of two pro-migratory genes, including cell division cycle 42 (CDC42) and matrix metalloproteinase 2 (MMP2) was induced by TCDD treatment. Dioxin exerts its toxic effects mainly through aryl hydrocarbon receptor (AhR) pathway. So the role of AhR pathway in the pro-migratory effects of TCDD was examined using an AhR antagonist, CH223191. We found that application of CH223191 significantly reversed the pro-migratory effects of TCDD. Interestingly, the basal ability of horizontal migration as well as basal levels of CDC42 and MMP2 expression were dramatically reduced suggesting a possible physiological role of AhR in maintaining the endogenous migration ability of the primary astrocytes. These findings support the notion that dioxin promotes astrocyte reactivation at molecular and cellular levels.     

Simultaneous quantification of fifty-one odor-causing compounds in drinking water using gas chromatography-triple quadrupole tandem mass spectrometry

A wide range of compounds with various structural features can cause taste and odor(TO)problems in drinking water. It would be desirable to determine all of these compounds using a simple analytical method. In this paper, a sensitive method combining liquid–liquid extraction(LLE) with gas chromatography-triple quadrupole tandem mass spectrometry(GC–MS/MS)was established to simultaneously analyze 51 odor-causing compounds in drinking water,including organic sulfides, aldehydes, benzenes, phenols, ethers, esters, ketones, nitrogenous heterocyclic compounds, 2-methylisoborneol and geosmin. Three deuterated analogs of target analytes, dimethyl disulfide-d6, benzaldehyde-d6 and o-cresol-3,4,5,6-d4,were used to correct the variations in recovery, and five isotope-labeled internal standards(4-chlorotoluene-d4, 1, 4-dichlorobenzene-d4, naphthalene-d8, acenaphthene-d10, phenanthrene-d10 respectively) were used prior to analysis to correct the variations arising from instrument fluctuations and injection errors. The calibration curves of the target compounds showed good linearity(R2 0.99, level = 7),and method detection limits(MDLs) below 1/10 of the odor threshold concentrations were achieved for most of the odorants(0.10–20.55 ng/L). The average recoveries of most of the analytes in tap water samples were between 70% and 120%, and the method was reproducible(RSD 20%, n = 7). Additionally, concentrations of odor-causing compounds in water samples collected from three drinking water treatment plants(DWTPs) were analyzed by this method.According to the results, dimethyl trisulfide, dimethyl disulfide and indole were considered to be the key odorants responsible for the swampy/septic odor. 2-Methylisoborneol and geosmin were detected as the main odor-causing compounds for musty/earthy odor in DWTP B.     

Application of interface material and effects of oxygen gradient on the performance of single-chamber sediment microbial fuel cells (SSMFCs)

Single-chamber sediment microbial fuel cells(SSMFCs) have received considerable attention nowadays because of their unique dual-functionality of power generation and enhancement of wastewater treatment performance. Thus, scaling up or upgrading SSMFCs for enhanced and efficient performance is a highly crucial task. Therefore, in order to achieve this goal, an innovative physical technique of using interface layers with four different pore sizes embedded in the middle of SSMFCs was utilized in this study.Experimental results showed that the performance of SSMFCs employing an interface layer was improved regardless of the pore size of the interface material, compared to those without such layers. The use of an interface layer resulted in a positive and significant effect on the performance of SSMFCs because of the effective prevention of oxygen diffusion from the cathode to the anode. Nevertheless, when a smaller pore size interface was utilized, better power performance and COD degradation were observed. A maximum power density of 0.032 mW/m~2 and COD degradation of 47.3% were obtained in the case of an interface pore size of 0.28 μm. The findings in this study are of significance to promote the future practical application of SSMFCs in wastewater treatment plants.     

One-step synthesis of Cu(II) metal–organic gel as recyclable material for rapid, efficient and size selective cationic dyes adsorption

Efficient removal of non-biodegradable and hazardous dyes from wastewater remains a hot research topic. Herein, a rationally designed a Cu(Ⅱ)-based metal–organic gel(Cu-MOG) with a nanoporous 3 D network structure prepared via a simple one-step mixing method was successfully employed for the removal of cationic dyes. The Cu-MOG exhibited high efficiency, with an adsorption capacity of up to 650.32 mg/g, and rapid adsorption efficiency, with the ability to adsorb 80% of Neutral Red within 1 min. The high adsorption efficiency was attributed to its large specific surface area, which enabled it to massively bind cationic dyes through electrostatic interaction, and a nanoporous structure that promoted intra-pore diffusion. Remarkably, the Cu-MOG displayed size-selective adsorption, based on adsorption studies concerning dyes of different sizes as calculated by density functional theory. Additionally, the adsorption performance of the Cu-MOG still maintained removal efficiency of 100% after three regeneration cycles. These results suggested that the Cu-MOG could be expected to be a promising and competitive candidate to conveniently process wastewater.     

Effect of air masses motion on the rapid change of aerosols in marine atmosphere

The impact of air masses motion on marine aerosol properties was investigated using an on-board single particle mass spectrometer(SPAMS) deployed for the determination of single particle size resolved chemical composition over Southeast China Sea. Two aerosol blooms(E1 and E2) were observed during the cruise. High average particle number count occurred in E1(7320), followed by E2(5850), which was more than 100–150 times of the average particle number count during normal periods. Particles were classified as four major sources, including continental source, shipping source, marine source, and transport source based on the mass spectral similarity. Transport source was identified as those particles with high particle number count occurred only during aerosol bloom period. Three sub-types of EC-Ca, OC-Ca, and Al-rich were classified as transport source.EC-Ca was the dominant particles of the transport source, accounting for more than 70%of the total particles in aerosol bloom events. A uni-modal size distribution in the size range of 0.1–2.0 μm was observed during normal period, while a bimodal distribution with a tiny mode(0.3 μm) and a coarse mode between 0.4 and 0.6 μm was present during aerosol bloom. The variation of aerosol source is consistent with air masses back trajectories, for the reason that most of the long-range air trajectories are from the ocean,while short air trajectories originate in the continental regions, which means that air masses have a significant impact on the aerosol physical–chemical properties along their tracks.     

中国碳排放及影响因素的市域尺度分析

评估区域碳排放及其与社会经济状况的关系对于制定碳减排措施至关重要.以中国339个地级及以上城市(不含新疆部分城市和港澳台地区)为研究对象,探究了非化石能源占比、土地开发度、常住人口城镇化率、第二产业占比、人均GDP和人均建设用地面积对人均CO₂排放量的影响.通过构建模拟人均CO₂排放量的贝叶斯信念网络,识别各因素对人均CO₂排放量的全局影响;采用多尺度地理加权回归模型,分析各因素对人均CO₂排放量的局部影响.结果表明：(1)2020年,中国地级及以上城市人均CO₂排放量呈现出由南向北递增,东部沿海向内陆递减的格局.(2)从全局来看,人均CO₂排放量对各因素的敏感性从高到低依次为：人均建设用地面积>人均GDP>常住人口城镇化率>土地开发度>第二产业占比>非化石能源占比.(3)从局部来看,各因素与人均CO₂排放量的空间关系方向与全局关系一致,关系强度上存在空间异质性.(4)清洁能源、脱碳技术、土地节约集约利用...     

Performance of an aerodynamic particle separator

This compact, high-flow device aerodynamically separates small particles from a gas stream by a series of annular truncated airfoils. The operating concept, design and performance of this novel particle separator are described. Tests results using corn starch and post-cyclone coal fly ash are presented. Particle collection efficiencies of 90% for corn starch and 70% for coal fly ash were measured at inlet velocities of 80 ft s⁻¹ (2700 cfm) and (6 inches) water pressure drop with particle loading up to 4 gr ft⁻³ in air at standard conditions. Results from computer modeling using FLUENT are presented and compared to the tests. The aerodynamic particle separator is an attractive alternative to a cyclone collector.     

辅助矿山救护队的建设工作应该加强

在现代煤矿里，灾害和事故仍然是不可避免的。采取减小组织内成员的自由度来强化专业救灾机构的整体功能固然重要，但非专业化的辅助矿山救护队的建设工作更应加强。因为他们亲临现场，熟悉灾情，又处于救灾的黄金时间里。因此，对是否酿成灾害和灾害中损失的控制问题，辅助矿山救护队有更多的优势。     

以可持续发展理论指导社会发展综合实验区的实践

社会发展综合实验区中中国可持续发展战略的实验基地，本文对实验区如何按可持续发展原则，结合当地的人口、资源、环境状况，制宁长远的可持续发展的生态规划做了较系统的论述。