Toxicity assessment and histopathological analysis of nano-ZnO against marine fish (Mugilogobius chulae) embryos

The toxicity of nano-materials has received increasing attention in recent years.Nevertheless,relatively few studies have focused on their oceanic distributions and toxicities.In this study,we assessed nano-ZnO toxicity in marine organisms using the yellowstriped goby(Mugilogobius chulae).The relative differences in nano-ZnO dissolution and dispersal in seawater and fresh water were also investigated.The effects of nano-ZnO on embryonic development,deformity,hatching,mortality,and histopathology were analyzed.In addition,the effects of the Zn~(2+) concentration on M.chulae hatching and mortality were compared.The results showed that nano-ZnO had higher solubility in seawater than in fresh water.Nano-ZnO significantly inhibited hatching.By the fifth day of exposure,the LC_(50) of nano-ZnO was 45.40 mg/L,and the mortality rate spiked.Hatching inhibition and lethality were dose-dependent over a range of1–25 mg/L nano-ZnO.Zn~(2+) inhibited hatching and increased lethality,but its effects were weaker than those of nano-ZnO at the same concentrations.Nano-ZnO also induced spinal bending,oedema,hypoplasia,and other deformities in M.chulae embryos and larvae.Histopathology revealed vacuolar degeneration,hepatocyte and enterocyte enlargement,and morphological abnormalities of the vertebrae.Therefore,nano-ZnO caused malformations in M.chulae by affecting embryonic growth and development.We conclude that nano-ZnO toxicity in seawater was significantly positively correlated with the associated Zn~(2+) concentration and sedimentary behaviour.The toxicity of nano-ZnO was cumulative and showed a critical point,beyond which embryonic and developmental toxicity in marine fish was observed.     

How does the social context fuel the proactive fire? A multilevel review and theoretical synthesis

The role of social context (e.g., leadership, team climate, and organizational support) in shaping employee proactive behavior has received considerable attention and has been investigated across multiple forms of proactive behavior. However, the research has not been well integrated. In this review, we adopt a multilevel approach to synthesize what is known about how social context factors influence employees' proactive behavior, as well as what mechanisms underpin these effects. Our analyses show that leader‐, team‐, and organization‐related social context factors mainly influence employee proactivity through shaping “reason to,” “can do,” and “energized to” states (i.e., proactive motivational states) via individual‐, team‐, and cross‐level processes. That has been most frequently investigated is the effect of the discretionary social context, particularly leadership, on proactive behavior. We also review the interaction effects between social context factors and other factors on employee proactive behavior and found inconsistent support for the motivational‐fit perspective that stimuli with the same directions enhance each other's effect. We offer a research agenda to advance theoretical insights on this important topic.     

2013-2015年十堰市环境空气质量变化趋势分析研究

利用十堰市空气自动监测站的监测数据,采用综合指数、空气质量指数(AQI)和Spearman秩相关系数法等评价方法,研究十堰市2013年-2015年环境空气质量变化情况及其影响因素,为城市的大气污染防治提供治理思路.结果表明:2013年-2015年十堰市城区空气质量逐年好转,除PM10和PM2.5外,其他因子均达标,污染物贡献比例中,PM10和PM2.5污染负荷占比超过50%,为主要污染物;十堰市城区空气质量整体呈夏季较好,冬季较差的趋势;全市中开发区铁二处空气质量较好,张湾区刘家沟空气质量较差;结合自然因素和人为因素,综合分析空气质量的变化情况,通过调整能源结构、减少污染源排放和使用清洁能源等多项措施,并注意季节特征和加强预警预报工作,进而改善空气质量.     

对柴油污染土壤洗涤修复表面活性剂的筛选及增效机制探究

分别采用5种表面活性剂十二烷基硫酸钠(SDS)、十二烷基苯磺酸钠(SDBS)、皂苷(saponin)、曲拉通X-100(TX-100)、聚氧乙烯月桂醚(Brij35)对柴油污染土壤进行清洗,考察pH、温度、搅拌时间、污染时长及助剂的使用对清洗效果的影响。并用Zeta电位仪对溶液电位,及接触角仪对清洗前后的土壤进行代表值的测定。结果表明:溶液浓度越大,清洗效果越好,对于柴油污染20 d的土壤,升高清洗温度和添加H_2O_2辅助清洗可提高柴油洗脱率;离子型表面活性剂的作用效果类似但存在差异,SDS在pH=10时使用最佳,柴油洗脱率可达65%,并可防止二次污染发生;SDBS则在pH=7时清洗效果最佳,洗脱率达59.3%;实验筛选出皂苷为较理想的清洗剂,与H_2O_2联用,柴油洗脱率最高可以达到75%;对于柴油污染130d土壤,延长清洗搅拌时间,可改善清洗效果。Zeta电位测定表明,表面活性剂与土壤粒子均带负电荷,"同性相斥"作用可防止二次污染。清洗后受柴油污染土壤的接触角变小,亲水性得到恢复。     

粉末活性炭的Fenton氧化再生

采用Fenton氧化法对吸附处理染料废水后的饱和粉末活性炭(饱和炭)进行再生,考察了饱和炭的再生效果及其主要影响因素。实验结果表明:饱和炭的最佳再生条件为H2O2投加量6.5 mmol/g、再生p H 3.0、H2O2与Fe2+的摩尔比10、再生时间1 h;最佳条件下的再生率(再生粉末活性炭(再生炭)与新粉末活性炭对废水COD去除率的百分比)约为60%;使用最佳再生条件下得到的再生炭对废水进行吸附处理,废水的COD去除率和脱色率分别约为27%和67%。     

电极材料对电动修复尾矿周边铅污染土壤的影响研究

影响土壤电动修复效率的因素很多,包括土壤类型、污染物性质、电压和电流大小、洗脱液组成和性质、电极材料和结构等.但很少有文献报道不同电极材料对电动修复土壤重金属污染的效率影响,文章采用不同电极材料(石墨、不锈钢和钛板)对尾矿附近的土壤进行电动修复,研究了修复效率及土壤pH随时间的变化情况.当电场强度为1 V/cm,采用石墨电板电动修复48 h总铅的去除效率为77％,不锈钢电极和钛电极的修复效率分别为64％和54％.石墨电极去除效率的提高归因于相比于不锈钢电极和钛电极,石墨电极提供更多的电子传递所需的活性界面.     

Risk factors affecting the severity of traffic accidents at Shanghai river-crossing tunnel

Objective: With increasing traffic volume and urban development, increasing numbers of underground tunnels have been constructed to relieve conflict between strained land and heavy traffic. However, as more long tunnels are constructed, tunnel traffic safety is becoming increasingly serious. Thus, it is necessary to acquire their implications and impacts. This study examined 4,539 traffic accidents that have occurred in 14 Shanghai river-crossing tunnels for the period 2011–2012 and analyze the correlation between potential factors and accident injury severity.

Methods: An ordered logit model was developed to examine the correlation between potential factors and accident injury severity.

Results: Results show that increased injury severity is associated with male drivers, drivers aged 65 years or older, accident time from midnight to dawn, weekends, wet road surface, goods vehicles, 3 or more vehicles, 4 or more lanes, middle speed limits (50–79 km/h), zone 3, extra-long tunnels (over 3,000 m), and maximum longitudinal gradient.

Conclusions: This article aims to provide useful information for engineers to develop interventions and countermeasures to improve tunnel safety in China.     

层次分析法在商场火灾风险评价中的应用研究

根据商场火灾的特点,并基于消防安全和系统安全的思想,从建筑、消防设施、商品、消防管理和外部环境5个方面建立了火灾风险评价指标体系;在此基础上通过层次分析法,计算得出各指标因子的权重值.并根据有关标准和规范,对各评价指标因子的风险分值进行划分.最后采用线性加权模型,计算商场的风险分值,得出火灾风险评价结果.     

Bioaccumulation,subcellular, and molecular localization and damage to physiology and ultrastructure in Nymphoides peltata (Gmel.) O. Kuntze exposed to yttrium

Bioaccumulation, subcellular distribution, and acute toxicity of yttrium (Y) were evaluated in Nymphoides peltata. The effects of Y concentrations of 1–5 mg L^?1 applied for 4 days were assessed by measuring changes in photosynthetic pigments, nutrient contents, enzymatic and non-enzymatic antioxidants, and ultrastructure. The accumulation of Y in subcellular fractions decreased in the order of cell wall > organelle > soluble fraction. Much more Y was located in cellulose and pectin than in other biomacromolecules. The content of some mineral elements (Mg, Ca, Fe, Mn, and Mo) increased in N. peltata, but there was an opposite effect for P and K. Meanwhile, ascorbate, and catalase activity decreased significantly for all Y concentrations. In contrast, peroxidase activity was induced, while initial rises in superoxide dismutase activity and glutathione content were followed by subsequent declines. Morphological symptoms of senescence, such as chlorosis and damage to chloroplasts and mitochondria, were observed even at the lowest Y concentration. Pigment content decreased as the Y concentration rose and the calculated EC₅₀ and MPC of Y for N. peltata were 2 and 0.2 mg L^?1 after 4 days of exposure, respectively. The results showed that exogenous Y was highly available in water and that its high concentration in water bodies might produce harmful effects on aquatic organisms. N. peltata is proposed as a biomonitor for the assessment of metal pollution in aquatic ecosystems.