邻苯二甲酸二丁酯诱导小鼠神经行为学改变及相关生理生化指标分析

探究邻苯二甲酸二丁酯诱导小鼠神经行为学改变及与细胞外调节蛋白激酶(ERK1/2)通路相关蛋白的关联.雄性KM小鼠36只,随机分成4组:生理盐水组、50 mg·kg~(-1)·d~(-1) DBP组、50 mg·kg~(-1)·d~(-1)维生素E(VE)组、DBP+VE组,连续灌胃处理28 d,观察Morris水迷宫结果,检测小鼠脑海马组织的氧化应激(活性氧(ROS)荧光强度、还原型谷胱甘肽(GSH)与丙二醛(MDA)含量)、脑源性神经营养因子(BDNF)、磷酸化cAMP反应元件结合蛋白(p-CREB)、caspase-3水平,Western blot分析ERK1/2及其磷酸化(p-ERK1/2)水平;HE、Nissl染色及Hoechst 33258荧光染色分析脑组织CA1区病理学变化.结果表明,与对照组比较,50 mg·kg~(-1)·d~(-1) DBP组小鼠的学习记忆下降,氧化应激、p-ERK1/2、caspase-3水平上升,BDNF、p-CREB表达下降,差异均有统计学意义(p0.05,p0.01);海马组织CA1病理学损伤及凋亡程度增加.给予抗氧化剂VE处理后,DBP+VE组小鼠的学习记忆上升,氧化应激、p-ERK1/2、caspase-3水平降低,BDNF、p-CREB表达上升,差异均有统计学意义(p0.05);海马组织CA1病理学损伤及凋亡程度降低.由此推测,DBP暴露导致小鼠海马组织CA1病理学损伤、神经元凋亡程度增加、学习记忆下降、其神经行为学改变可以通过添加VE得到缓解,相关生理生化指标测试表明ERK系统应激氧化性损伤机制参与介导了毒理学过程.     

基于Monte Carlo模拟的河流水质评价——以温瑞塘河为例

基于水质评价的综合污染指数（CWQI）法和水质指标实测含量的统计分析,应用Monte Carlo模拟方法,建立了河流水质评价的Monte Carlo-CWQI耦合模型并进行实例研究.通过建立的耦合模型和温瑞塘河流域14个监测断面2004~2010年的水质监测数据,定量分析各监测断面隶属于不同污染等级的概率水平和各水质指标对水体污染的影响程度.结果表明：温瑞塘河水系水质污染十分严重,勤奋、九山、东水厂、十字河、南白象、灰桥、新桥、米筛桥、仙门、光明、郭溪、瞿溪、西岙和梧田监测断面处于重度污染的概率分别为28.50%,0.55%,92.71%,59.73%,78.85%,39.38%,78.87%,83.09%,65.32%,78.08%,0.00%,0.96%,68.09%,86.06%;处于严重污染的概率分别为71.28%,0.01%,4.33%,39.76%,21.07%,60.59%,4.42%,12.41%,11.02%,21.24%,0.00%,0.02%,1.42%,13.12%.各监测断面总氮（TN）,氨氮（NH₃-N）和溶解氧（DO）的Spearman等级相关系数范围分别是0.41~0.76、0.25~0.63和0.14~0.66,是其他指标的2倍以上,表明影响该地区水质达标的主要因子是TN,NH₃-N和DO.本研究拓宽了河流水质评价的研究视角,能够为流域水环境管理提供丰富的决策依据.     

Enhanced nitrate reduction in water by a combined bio-electrochemical system of microbial fuel cells and submerged aquatic plant Ceratophyllum demersum

High nitrate(NO_3~-)loading in water bodies is a crucial factor inducing the eutrophication of lakes.We tried to enhance NO_3~-reduction in overlying water by coupling sediment microbial fuel cells(SMFCs)with submerged aquatic plant Ceratophyllum demersum.A comparative study was conducted by setting four treatments:open-circuit SMFC(Control),closed-circuit SMFC(SMFC-c),open-circuit SMFC with C.demersum(Plant),and closed-circuit SMFC with C.demersum(P-SMFC-c).The electrochemical parameters were documented to illustrate the bio-electrochemical characteristics of SMFC-c and P-SMFC-c.Removal pathways of NO_3~- in different treatments were studied by adding quantitative~(15)NO_3~- to water column.The results showed that the cathodic reaction in SMFC-c was mainly catalyzed by aerobic organisms attached on the cathode,including algae,Pseudomonas,Bacillus,and Albidiferax.The oxygen secreted by plants significantly improved the power generation of SMFC-c.Both electrogenesis and plants enhanced the complete removal of NO_3~- from the sediment–water system.The complete removal rates of added~(15)N increased by 17.6% and 10.2% for SMFC-c and plant,respectively,when compared with control at the end of experiment.The electrochemical/heterotrophic and aerobic denitrification on cathodes mainly drove the higher reduction of NO_3~- in SMFC-c and plant,respectively.The coexistence of electrogenesis and plants further increased the complete removal of NO_3~- with a rate of 23.1%.The heterotrophic and aerobic denitrifications were simultaneously promoted with a highest abundance of Flavobacterium,Bacillus,Geobacter,Pseudomonas,Rhodobacter,and Arenimonas on the cathode.     

Morphology, composition, and sources of individual aerosol particles at a regional background site of the YRD, China

Aerosol samples were collected at Lin'an, a background site of Yangtze River Delta(YRD).Morphology, size, composition, and mixing state of individual aerosol particles were characterized by transmission electron microscopy(TEM) coupled with energy dispersive X-ray spectroscopy(EDS), and the soluble ions of PM_(1.0) were studied by aerosol mass spectrometer(AMS). The daily average AMS mass concentrations of sulfate, nitrate, and ammonium were about 5.8, 8.6, and 5.6 μg/m~3, respectively. Individual aerosol particles were classified into seven types: S-rich, K-rich, organic matter(OM), soot, fly ash, metal, and mineral. S-rich particles were dominant in all size bins, and 51%(by number) of S-rich particles were internally mixed with other particles. The fraction of organic coating particles was 13.7% in morning, 25.2% in afternoon, and 11% in evening, suggesting that the strong photochemical process during afternoon produced more secondary organic aerosols(SOA) on the surface of inorganic particles. Fly ash and metal particles were abundant during the day, suggesting the influence of emissions from coal-fired power plants and steel plants. The results indicate that the intense industrial emissions in the YRD significantly transported to the background areas. PM_(2.5) concentration may be lower in background air than in urban air but complex mixing state of aerosol particles indicates that the long-range transported particles substantially influenced the background air quality.     

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.     

Air pollution characteristics and their relationship with emissions and meteorology in the Yangtze River Delta region during 2014–2016

With rapid economic growth and urbanization, the Yangtze River Delta(YRD) region in China has experienced serious air pollution challenges. In this study, we analyzed the air pollution characteristics and their relationship with emissions and meteorology in the YRD region during 2014–2016. In recent years, the concentrations of all air pollutants, except O_3,decreased. Spatially, the PM_(2.5), PM_(10), SO_2, and CO concentrations were higher in the northern YRD region, and NO_2 and O_3 were higher in the central YRD region. Based on the number of non-attainment days(i.e., days with air quality index greater than 100), PM_(2.5) was the largest contributor to air pollution in the YRD region, followed by O_3, PM_(10), and NO_2.However, particulate matter pollution has declined gradually, while O_3 pollution worsened.Meteorological conditions mainly influenced day-to-day variations in pollutant concentrations. PM_(2.5) concentration was inversely related to wind speed, while O_3 concentration was positively correlated with temperature and negatively correlated with relative humidity.The air quality improvement in recent years was mainly attributed to emission reductions.During 2014–2016, PM_(2.5), PM_(10), SO_2, NO_x, CO, NH_3, and volatile organic compound(VOC)emissions in the YRD region were reduced by 26.3%, 29.2%, 32.4%, 8.1%, 15.9%, 4.5%, and0.3%, respectively. Regional transport also contributed to the air pollution. During regional haze periods, pollutants from North China and East China aggravated the pollution in the YRD region. Our findings suggest that emission reduction and regional joint prevention and control helped to improve the air quality in the YRD region.     

屏蔽电机主泵双金属飞轮飞射物对承压边界完整性破坏作用

目的掌握反应堆冷却剂泵双金属飞轮飞射物对承压边界完整性的影响规律。方法基于ANSYS/LS-DYNA对飞轮保持环失效后钨合金块与承压边界的碰撞过程进行分析,模拟承压边界在重要因素(电机壳厚度、钨合金块数)的影响下对飞轮飞射物的包容过程。结果在保持飞射物入射初速度不变的情况下,当电机壳厚度小于118 mm时,发生非包容性失效。改变钨合金块数(4、8、12、16块),可以发现钨合金块数越多,飞射物对承压边界施加的破坏能量就越小。结论增加电机壳厚度、钨合金块数有利于承压边界能够很好地包容住所有飞射物。该研究成果对屏蔽电机主泵惰转飞轮的可靠性设计具有重要意义。     

基于Matlab/Simulink的导弹运输振动载荷分析

目的分析导弹在车辆运输中的振动载荷情况,为开展导弹结构可靠性分析和寿命预估提供输入条件。方法根据导弹运输车的动力学模型,利用Matlab/Simulink对不同路况条件下导弹运输车振动响应情况进行仿真计算,获得不同路况和运输车速时的振动响应情况。结果随着路面等级下降和车辆速度的增加,导弹运输车振动的幅值也相应增加。结论滤波白噪声方法模拟得到的时域路面功率谱与标准等级功率谱一致性较好,可以作为振动响应分析的输入激励。     

辽东湾东部海域核电冷源取水区的风险生物分析

我国近年来在核电冷源取水系统运行过程中,因海洋生物聚集或暴发等原因,屡次堵塞冷源取水系统,造成取水水泵、发电机组甚至反应堆异常停止,给核电正常运行带来了较大风险。建立核电冷源取水区的风险生物目录,并有针对性地研究其监测、预警技术和防控对策,是核电冷源取水系统安全运行的前提。通过2015年6~11月在红沿河核电取水区及其临近海域的调查,筛选出对冷源取水系统风险值为"高"的海洋生物主要有长石莼（缘管浒苔）（Ulva linza）、孔石莼（Ulva pertusa）、海月水母（Aurelia aurita）、沙蛰（Nemopilema nomurai）、球型侧腕水母（Pleurobrachia globosa）、中国毛虾（Acetes chinensis）等。其中海月水母的风险分级基准为:大于或等于500 ind./（net.h）时风险为"高",为红色预警级别;大于300而小于500 ind./（net.h）时风险为"中",为黄色预警级别;大于100而小于300 ind./（net.h）时风险为"低",为蓝色预警级别。     

京津冀城市群冬季二次PM2.5的时空分布特征

二次组分是造成京津冀城市群冬季PM_2.5污染的重要因素.采用CO示踪法,估算2017～2021年冬季京津冀城市群二次PM_2.5浓度,并分析其时空分布特征,探讨区域二次PM_2.5的影响因素.结果表明,2017～2021年冬季京津冀区域PM_2.5浓度下降趋势明显,河北中南部一次PM_2.5下降幅度最大,二次PM_2.5浓度年际波动平稳,北京和天津二次PM_2.5占比明显高于其他城市.随着污染程度加剧,一次PM_2.5和二次PM_2.5质量浓度均有不同程度的增加,二次PM_2.5占比呈显著增大趋势.与直接测量结果相比,CO示踪法获得的结果偏低,与冬季CO浓度较高,一次PM_2.5浓度高估有关,选取合适的一次气溶胶基准值是改进该方法,获取合理估算值的关键.