Biological effects of palytoxin-like compounds from Ostreopsis cf. ovata: A multibiomarkers approach with mussels Mytilus galloprovincialis

Massive blooms of the harmful benthic dinoflagellate Ostreopsis cf. ovata are of growing environmental concern in the Mediterranean, having recently caused adverse effects on benthic invertebrates and also some intoxication episodes to humans.The toxicological potential of produced palytoxin-like compounds was investigated in the present study on a typical marine sentinel species, the mussel Mytilus galloprovincialis. Organisms were sampled during various phases of a O. cf. ovata bloom, in two differently impacted sites. The presence of the algal toxins was indirectly assessed in mussels tissues (mouse test and hemolysis neutralization assay), while biological and toxicological effects were evaluated through the measurement of osmoregulatory and neurotoxic alterations (Na⁺/K⁺-ATPase and acetylcholinesterase activities), oxidative stress responses (antioxidant defences and total oxyradical scavenging capacity), lipid peroxidation processes (level of malondialdehyde), peroxisomal proliferation, organelle dysfunctions (lysosomal membrane stability, accumulation of lipofuscin and neutral lipids), immunological impairment (granulocytes percentage).Obtained results demonstrated a significant accumulation of algal toxins in mussels exposed to O. cf. ovata. These organisms exhibited a marked inhibition of the Na⁺/K⁺-ATPase activity and alterations of immunological, lysosomal and neurotoxic responses. Markers of oxidative stress showed more limited variations suggesting that toxicity of the O. cf. ovata toxins is not primarily mediated by an over production of reactive oxygen species. This study provided preliminary results on the usefulness of a multi-biomarker approach to assess biological alterations and toxicological events associated to blooms of O. cf. ovata in marine organisms.     

滤料粒径对给水曝气生物滤池运行稳定性的影响

利用给水曝气生物滤池(UBAF)处理刘屋洲水源水,考察了不同陶粒粒径对氨氮、高锰酸盐指数的去除效果以及水头损失变化的影响。结果表明,陶粒3～5 mm的UBAF对氨氮、高锰酸盐指数的去除效果较高,但是其水头损失较大,且反冲洗前后水头损失变化偏大,不利于UBAF稳定运行。陶粒6～10 mm的UBAF运行状况良好,氨氮的去除率为73.8%,高锰酸盐指数的去除率为18.6%,滤池24 h过滤水头损失<0.4 m,反冲洗前后过滤水头损失变化量<5 cm。其出水氨氮和高锰酸盐指数均达到《生活饮用水卫生标准》(GB5749-2006),滤池的水头损失小,反冲洗前后也变化甚微。进一步的实验表明陶粒破碎会导致滤料粒径级配变化,使得水头损失增加。     

Development and modification of permanent magnet brushed DC motor for hybrid photovoltaic-operated solar systems

A modified brushed permanent magnet DC (PMDC) motor has been developed and fabricated for a photovoltaic (PV)-operated solar systems. The conventional PMDC motor has been plagued with constraints, the most critical being ingestion of vapours of working fluid inside the rotor and stator, damaging the insulation of windings and forming a thin film of moisture between commutator and brushes. This flaw results into a very low mean time between failures of the motor. In the past, many attempts have been made where-in variety of seals to isolate the working fluid vapours from inner parts of motor have been tried out, but to no avail. Even Brushless DC motors have been designed in the past but their exorbitant cost makes the entire arrangement not viable economically. The modification attempted in this article overcomes the problem of working fluid ingestion inside the motor. It is found that mass flow rate of working fluid obtained at maximum peak sunshine hours is 17.5 l/min at 3030 rpm of motor driven by a PV module of 40 W at 16.20 V. This low-cost modified PMDC motor has been robust with high mean time between failures as no breakdown observed during 18 months of operation.     

Non-intrusive characterization of the redox potential of landfill leachate plumes from self-potential data

Contaminant plumes (e.g., associated with leakages from municipal landfills) provide a source of natural electrical potentials (or "self-potentials") recordable at the Earth's surface. One contribution to these self-potentials is associated with pore water flow (i.e., the "streaming potential"), and the other is related to redox conditions. A contaminant plume can be regarded as a "geobattery": the source current potentially results from the degradation of the organic matter by micro-organisms, which produces electrons. These electrons are then carried by nanowires that connect bacteria and thorough metallic particles that precipitate in areas of strong redox potential gradient. In the case of the Entressen landfill (South of France), reported here, the hydraulic head differences measured in piezometers outside the contaminant plume is strongly linked to the surface self-potential signals, with a correlation coefficient of -0.94. We used a Bayesian method that combines hydraulic head and self-potential data collected outside the contaminated area to estimate the streaming potential component of the collected self-potential data. Once the streaming potential contribution was removed from the measured self-potentials, the correlation coefficient between the residual self-potentials and the measured redox potentials in the aquifer was 0.92. The slope of this regression curve was close to 0.5, which was fairly consistent with both finite element modelling and the proposed geobattery model.     

三峡库首移民安置区土地资源、移民经济状况及移民满意度的调查与分析

针对三峡工程蓄水和移民搬迁对库首地区农业生产和居民生活造成的影响,对移民安置前后三峡库首地区的秭归、兴山、巴东等县乡镇土地资源状况进行了统计分析,并选择典型乡镇移民户作为研究对象,实地调查了移民安置区移民户的经济收支情况及其对移民安置的满意度。结果表明：三峡工程蓄水后,库区低海拔地区耕地淹没,农村可用耕地总量减少,人均耕地也有所减少,人地资源矛盾比较突出。移民主要收入来源为劳务、种植业和养殖业收入,其中劳务收入比例较大,农户家庭经济支出主要是以生活支出为主,移民搬迁对部分农民经济收入产生较大影响。移民搬迁以后,库区农村的居住环境、住宅条件、生活条件和交通条件均较移民前有明显改善,农户普遍比较满意。库首地区的移民政策落实较好,大部分人对未来发展充满信心,对三峡工程表示支持和肯定。搬迁安置对农村生态环境状况产生了影响,存在自然灾害和病虫害增多,农村废弃物处理设施不足等问题,应当引起政府对库区生态环境问题的足够重视。〖     

Sensitivity of Head and Cervical Spine Injury Measures to Impact Factors Relevant to Rollover Crashes

Objective: Serious head and cervical spine injuries have been shown to occur mostly independent of one another in pure rollover crashes. In an attempt to define a dynamic rollover crash test protocol that can replicate serious injuries to the head and cervical spine, it is important to understand the conditions that are likely to produce serious injuries to these 2 body regions. The objective of this research is to analyze the effect that impact factors relevant to a rollover crash have on the injury metrics of the head and cervical spine, with a specific interest in the differentiation between independent injuries and those that are predicted to occur concomitantly.

Methods: A series of head impacts was simulated using a detailed finite element model of the human body, the Total HUman Model for Safety (THUMS), in which the impactor velocity, displacement, and direction were varied. The performance of the model was assessed against available experimental tests performed under comparable conditions. Indirect, kinematic-based, and direct, tissue-level, injury metrics were used to assess the likelihood of serious injuries to the head and cervical spine.

Results: The performance of the THUMS head and spine in reconstructed experimental impacts compared well to reported values. All impact factors were significantly associated with injury measures for both the head and cervical spine. Increases in impact velocity and displacement resulted in increases in nearly all injury measures, whereas impactor orientation had opposite effects on brain and cervical spine injury metrics. The greatest cervical spine injury measures were recorded in an impact with a 15° anterior orientation. The greatest brain injury measures occurred when the impactor was at its maximum (45°) angle.

Conclusions: The overall kinetic and kinematic response of the THUMS head and cervical spine in reconstructed experiment conditions compare well with reported values, although the occurrence of fractures was overpredicted. The trends in predicted head and cervical spine injury measures were analyzed for 90 simulated impact conditions. Impactor orientation was the only factor that could potentially explain the isolated nature of serious head and spine injuries under rollover crash conditions. The opposing trends of injury measures for the brain and cervical spine indicate that it is unlikely to reproduce the injuries simultaneously in a dynamic rollover test.     

真空排污系统管网的铺设

污水在压差的作用下 ,向前运动一段时间后 ,回落到各提升段的低洼处 ,所引起的激励波继续向前传播 ,激发前方静止的污水再次运动起来。这样经多次提升 ,污水越过上坡进入收集罐。由于只考虑向下坡度小于 2 %的管线的摩擦损失及各提升段的静压头损失 ,因此 ,根据不同的系统运行水平 ,污水提升高度可达 4.5～ 6m ,输送距离可达4km。     

我国不同类型稀土矿区环境卫生学调查──矿区农民自然生活环境和头发中稀土水平

对我国有代表性的３种类型稀土矿区内农民自然生活环境（耕地土壤、饮用井水、天然植物和植物性食物）和头发中稀土含量进行了卫生学调查研究,初步了解了其稀土暴露、吸收和蓄积水平。结果表明：稀土矿区内,除耕地土壤中稀土含量（６８０—１２００ｍｇ／ｋｇ）明显高于对照地区、某些天然植物有富积稀土（１６．８—５７．２μｇ／ｇ）的能力外,浅井水（２．６—２１．０μｇ／Ｌ）、粮食＜（０．０５—３．１５μｇ／ｇ）和蔬菜（０．０６—１．８２μｇ／ｇ）中稀土含量仅是稍高于对照地区趋势;矿区农民平均每人每日稀土经日摄入量估计值〔（４９８．３—１７０８．１μｇ／（ｄ·人）］与相应对照点基本一致;仅江西轻稀土矿观察点［（６５９．４μｇ／（ｄ·人）］稍高于对照点［４９８．３μｇ／（ｄ·人）］。江西２矿区内农民发中稀土含量（０．５３—１５．０２μｇ／ｇ）均显著高于本地区对照点以及山东稀土矿区内农民发稀土水平（＜０．２０—１．１２μｇ／ｇ,Ｐ＜０．０５）,并接近或超过山东稀土矿矿工水平（０．４３—８．７６μｇ／ｇ,Ｐ＜０．０５）,但其平均每人每日稀土经日摄入量明显低于山东矿区农民摄入水平［１７０８．ｌμｇ／（ｄ·人）］。江西离子吸附型稀土矿区内     

化工香料生产企业真空泵优化技改的环境效益分析

以钱塘江上游某化工香料企业的泵优化技改为例,通过分析物料输送泵优化技改前后的工艺流程和污染物排放情况,从而佐证化工行业物料输送泵的选型与污染物排放量是密切相关的,可以达到指导该类项目的环境影响评价和清洁生产审核,同时也能为企业的节能减排提供一定的技术依据。     

海水消防泵站的设计思路

分析了海水消防泵使用过程中出现的问题,并就存在的问题提出了海水消防泵站设计的几个思路.