稀土矿城市不同季节大气可吸入颗粒物中稀土含量特征及颗粒物细胞毒性

为探讨典型稀土矿城市不同季节大气可吸入颗粒物(inhalable particulate matter,PM10)中稀土元素污染特征及其细胞毒性响应,将前期采集于包头市的PM10颗粒物进行提取,检测PM10中的稀土元素(rare earth elements,REEs)含量,并将人肺上皮细胞(A549)暴露于不同浓度水平(25,50,100μg·m L-1)的PM10样品和标准颗粒物1649b(standard reference material,SRM1649b)暴露液,用WST-1法测定暴露24 h后的细胞活性,用2’7’二氯荧光素二醋酸盐(2’7’-dichlorofluorescein diacetate,DCFH-DA)荧光探针法和彗星实验分别测定暴露3 h后的细胞内活性氧(reactive oxygen species,ROS)产生水平和DNA双链损伤程度。结果表明,包头春、夏季大气PM10和SRM1649b均引起A549细胞活性下降,并诱导细胞内ROS生成量增加,造成显著的细胞内DNA损伤,含REEs的大气颗粒物毒性显著高于标准颗粒物。与春季相比,包头夏季PM10对细胞活性的抑制程度更高,造成更多的DNA双链损伤,从而表现出更强的细胞毒性和遗传毒性。包头PM10呈现明显的轻稀土元素(light rare earth elements,LREEs)富集,铈(Ce)、钷(Pm)、镧(La)和钕(Nd)含量占稀土总量的50%以上。LREEs均与细胞活性和细胞内ROS产生水平呈负相关性,包头春季和夏季PM10中稀土元素含量的差异是导致包头PM10细胞毒性效应不同于标准颗粒物且具有季节性差异的原因之一。     

The influence of deoxynivalenol and zearalenone on steroid hormone production by porcine ovarian granulosa cells in vitro

Fusarium mycotoxins deoxynivalenol (DON) and zearalenone (ZEA) are frequently occurring in feed of pigs together. The aim of this study was to evaluate the possible in vitro effects of DON and ZEA, alone or their combination on steroid secretion of porcine ovarian granulosa cells (GCs). A species-specific model with porcine ovarian GCs was used to study the potential endocrine disrupting effects of DON and ZEA alone and in co-exposure. Progesterone (P4) and estradiol (E2) were determined by radioimmunoassay (RIA) and enzyme-linked immunosorbent assay (ELISA). The results of this study demonstrate that DON alone at the higher concentrations may act to stimulate P4 (at 1,000, 2,000, 3,000 and 5,000 ng mL^?1 but not 10 and 100 ng mL^?1) and E2 (at 2,000, 3,000 and 5,000 ng mL^?1 but not 10, 100 and 1000 ng mL^?1) secretion. The effects of ZEA on P4 and E2 secretion were not confirmed. DON in combination with the other fusariotoxin ZEA may impair steroidogenesis. Results aslo demonstrate different toxicological effects of fusariotoxins on follicle stimulating hormone-induced secretion of P4 and E2. All these results taken together suggest that fusariotoxin and their interactions can impact ovarian steroidogenesis, thereby demonstrating their potential reproductive effects in pigs.     

Canopy slope effect on the performance of the solar chimney power plant

Solar chimney power plants constitute an impressive construction by its size and its output seems low for its dimensions. Although many works have been carried out on the subject, there is still much scientific and technical improvement to be done. In the present work, we consider the modeling of turbulent flow under the effect of natural convection within a solar chimney power plant (SCPP) by performing numerical simulation using the Saturne Code coupled with Syrthes code. The objective of the study is the analysis of the collector cover slope influence on the performance of the SCPP in two cases. In the first case, the storage system considered is composed solely of the ground under the collector. For the second case, the storage system is made, in addition to the ground, of a 10 cm thick tub filled with water, covering the entire surface of the collector. The concept of minimizing the entropy production is also studied with the objective of optimizing the geometric configuration as well as the effect of the collector cover slope on the efficiency of SCPP. The boundary conditions are defined according to the meteorological data for a typical day available on the site of Adrar, Algeria. The results allow us to focus on the storage system influence on the SCPP performance and the duration of its operation after sunset. This leads to the improvement of the global efficiency of the SCPP. Results show the positive impact of the extra storage media use and the configuration which improves the velocity at the chimney entrance.     

Characterization of the pro-inflammatory potencies of purified Jatropha phorbol esters by a gene expression-based in vitro bioassay

The oil extracted from Jatropha seeds is an emerging biodiesel feedstock that also contains several pro-inflammatory phorbol esters. These phorbol esters can elicit adverse inflammatory responses through activation of the protein kinase C, as previously described for the prototypical phorbol ester 12-O-tetradecanoylphorbol-13-acetate. We extracted and purified the six phorbol esters identified in Jatropha oil and assessed their pro-inflammatory activities using a recently developed gene expression-based bioassay. Borrowing from an approach used for the assessment of dioxin toxicity, we expressed their pro-inflammatory potencies in relation to the potency of 12-O-tetradecanoylphorbol-13-acetate (in terms of 12-O-tetradecanoylphorbol-13-acetate toxic equivalency factors). The pro-inflammatory potencies of Jatropha phorbol esters were orders of magnitudes below the potency of 12-O-tetradecanoylphorbol-13-acetate. Interestingly, the cytotoxicity of phorbol esters did not appear to be directly related to their pro-inflammatory potencies. Calculations based on phorbol ester potencies and concentrations led to overestimation of the pro-inflammatory activity of Jatropha oil, as measured by the same gene expression-based bioassay. The preliminary results presented here suggest that further work on the described approach may lead to the development of valuable tools and metrics to quantify and predict the pro-inflammatory activities of complex phorbol ester mixtures.     

Removing perfluorooctane sulfonate and perfluorooctanoic acid from solid matrices, paper, fabrics, and sand by mineral acid suppression and supercritical carbon dioxide extraction

The removal of perfluorooctanoic acid (PFOA) and perfluorooctane sulfonate (PFOS) from solid matrices has received considerable attention because of the environmental persistence, bioaccumulation, and potential toxicity of these compounds. This study presents a simple method using concentrated HNO₃ as a suppression agent, and methanol-modified supercritical carbon dioxide (Sc-CO₂) extraction for removing PFOS and PFOA from solid matrices. The optimal conditions were 16 M HNO₃ and 20% (v/v) methanol containing Sc-CO₂, under a pressure of 20.3 MPa and a temperature of 50 °C. Extraction time was set at 70 min (40 min for static and 30 min for dynamic extraction). PFOA and PFOS were identified and quantitated by liquid chromatography/mass spectrometry. The extraction efficiencies (with double extractions) were close to 100% for PFOA and 80% for PFOS for both paper and fabric matrices. The extraction efficiencies for sand were approximately 77% for PFOA and 59% for PFOS. The results show that this method is accurate, and effective, and that it provides a promising and convenient approach to remediate the environment of hazardous PFOA and PFOS contamination.     

含油污水处理用旋流气浮一体化设备的CFD数值模拟

借助商业计算流体动力学(CFD)软件Fluent,对国内自主研发的含油污水处理用BIPTCFU-1型旋流气浮一体化设备进行内部流场的数值模拟研究,讨论了射流器挡板和缓流板等主要结构参数对设备分离性能的影响,并对污水处理量和回流比等运行参数对设备除油率的影响进行了评估。为下一步通过CFD数值模拟手段进行优化设计,进而成功研发含油污水旋流气浮一体化处理设备奠定了较为坚实的基础。     

袋式除尘器内部流场的数值模拟

袋式除尘器内部气流分布不均会加剧滤袋磨损,降低除尘效率。采用计算流体动力学(CFD)数值模拟方法对除尘器内部流场进行研究,分析了气流的轨迹及其在各气室中的速度分布。发现原设计中气流分布不均匀的现象比较明显,提出了在进气通道内添加气流均布板的改进措施。结果表明:改进后,除尘器箱体内部气流分布较均匀,各滤袋气流分配系数的波动幅度减小,各气室综合流量不均幅值降低。研究结果为袋式除尘器的结构优化设计提供了理论依据。     

臭氧接触池与清水池合建的三维数值模拟

利用计算流体力学软件Fluent,结合标准κ-ε模型和组分输运模型,建立了臭氧接触池和清水池的三维紊流模型;通过计算流体的停留时间分布曲线(RTD),对臭氧接触池的水力效率进行了模拟研究。在此基础上,提出了在清水池前段第一廊道设置臭氧接触池的合建方案。结果表明:单一的臭氧接触池水力效率较低,T10/HRT值仅为0.42;而臭氧接触池与清水池经过合建后,T10/HRT值达到0.65,其臭氧消毒水力效率提高了55%。     

不同阳极微生物燃料电池产电性能的比较

微生物燃料电池在处理废水的同时可以产生电能,有希望同时解决废水再利用和能量再产生的问题。采用单室无膜空气阴极微生物燃料电池,处理模拟生活污水,探讨MFC处理模拟废水的效果。研究了以碳布(MFC1)、碳布负载碳纳米管(MFC2)、碳纳米管(MFC3)和泡沫镍(MFC4)作为4种不同的阳极材料,对MFC系统的启动、内阻和产电特性进行比较。结果表明,4种不同阳极MFC在水力停留时间24 h的条件下,对COD有很好的去除作用,其中MFC2的COD去除效率最大,为91.4%。在不影响MFC系统处理废水效果的前提下,实验得到4种阳极MFC系统中MFC2具有最小的内阻,为173.7Ω;并且其功率密度也大于其他3种MFC,达到401.2 mW/m2。