Efficient water desalination using photo-responsive ZnO polyamide thin film nanocomposite membrane

Environmental Chemistry Letters - Membrane separation technology has become one of the most frequently used techniques to secure adequate water resources for human consumption and other...     

Detection of oxidative stress and DNA damage in freshwater snail <Emphasis Type="Italic">Lymnea leuteola</Emphasis> exposed to profenofos

Extensive production and use of organophosphate pesticide in agriculture, has risen concerned about its ecotoxicity and risk assessment of insecticides, which are more important. Therefore, the present investigation was aimed to study the induction of oxidative stress and DNA damage by organophosphate insecticide profenofos (PFF) in freshwater snail Lymnea luteola (L. luteola). The median lethal value (96 h LC₅₀) of PFF was estimated as 1.26 mg/L for L. luteola in a semi-static system and on the basis of LC₅₀ value three concentrations viz., 0.126 (1/10 of LC₅₀, Sublethal I), 0.63 (1/2 of LC₅₀, Sublethal II) and 0.84 mg/L (2/3 of LC₅₀, Sublethal III) were determined. Snails were exposed to above-mentioned concentrations of PFF along with solvent control (acetone) and negative control for 96 h. The haemolymph was collected at 24 and 96 h of after treatment. In heamolymph of PFF exposed snail, lipid peroxide, glutathione reduced glutathione S transferase and superoxide dismutase activities at the tested concentrations significantly differ from those in the control. The genotoxicity induced in hemocytes of treated snails was measured by alkaline single cell gel electrophoresis assay. The data of this experiment demonstrated significantly enhancement of oxidative stress and DNA damage in the treated snails as compared to controls. Also, we observed statistically significant correlations of ROS with DNA damage (% tail DNA) (R² = 0.9708) for 24 h and DNA damage (R2 = 0.9665) for 96 h.

Results of the current experiment can be useful in risk evaluation of PFF among aquatic organisms. The study confirmed the use of comet assay for in vivo laboratory experiments using freshwater snail for selecting the toxic potential of industrial chemicals and environmental contaminants.

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Effects of physicochemical factors on PAH degradation by Planomicrobium alkanoclasticum

Polycyclic aromatic hydrocarbons (PAHs) are environmental pollutants that are mutagenic, carcinogenic, and toxic to living organisms. Here, the ability and effectiveness of selected bacteria isolated from an oil‐contaminated area in biodegrading PAHs were evaluated, and the optimal conditions conducive to bacterial PAH biodegradation were determined. Of six bacterial isolates identified based on their 16S rRNA sequences, Planomicrobium alkanoclasticum could subsist on and consume nearly all hydrocarbons according to the 2,6‐dichlorophenolindophenol assay. The efficacy of this isolate at PAH biodegradation was then empirically confirmed. After 30 days of incubation, P. alkanoclasticum degraded 90.8% of the 16 PAH compounds analyzed and fully degraded eight of them. The optimum P. alkanoclasticum growth conditions were 35°C, pH 7.5, and NaNO₃ as the nitrogen source. Under these biostimulant conditions, P. alkanoclasticum degraded 91.4% of the total PAH concentration and completely decomposed seven PAHs after 15 days incubation. Hence, P. alkanoclasticum is an apt candidate for the biodegradation of PAHs and the bioremediation of sites contaminated by them.     

Development of shopping centres in Jeddah

Recently developed shopping centres have become one of the main features of shopping activities in Jeddah. In fact the city of Jeddah experienced a surprising increase in the development of shopping centres during the last decade. Developers entered the land development process with the intention of realising profits from a long‐term investment, but a considerable number of shopping centres were developed on the basis of insufficient or no feasibility studies thereby underestimating or neglecting expected rate of return and occupancy. Spatially, shopping centres present distinctive spatial and rental value patterns. This article is concerned with explaining the supply side of shopping centres by examining the development process through which they were built. The analytical framework is based on discussing the interaction of three sets of variables: contextual factors, including land policy and market mechanisms; site characteristics, and the developer's characteristics.     

Individual demographic differences and job satisfaction

Empirical research and theoretical literature support the notion that demographic differences among employees are associated with job satisfaction. However, the evidence is inconsistent, and little is known about the stability of many of the reported relationships. A meta-analysis was conducted involving 21 independent studies and over 10,000 employees to discern selected population relationships. Results indicated that, with the exception of age and organizational tenure, associations do not differ significantly from zero. Large amounts of variance around each mean correlation, however, warranted a moderator analysis. Results indicated that the strength and pattern of associations differ by organizational type. Theoretical propositions and implications for future research in the area of demographic moderators are discussed.     

我国南方某省1988～1992年工伤调查分析

通过对南方某省１９８８～１９９２年工伤发生情况的调查，五年间工伤事故数、工伤死亡率及重伤率有逐年增加的趋势，煤炭、交通、建筑三个行业的工伤死亡人数约占工伤死亡总数的５０％；县以下乡镇企业中的工伤事故数、死亡率及重伤率均居首位。工伤事故中造成死亡的原因主要集中在物体打击、触电、高空坠落；引起重伤的原因集中在机械伤害、物体打击、车辆伤害和高空坠落。因此在劳动安全卫生管理工作上，要采取一些强有力的干预措施，特别要加强对乡镇工业企业及那些易发生工伤事故企业的管理。     

Indium tin oxide nanoparticles-mediated DNA fragmentation and cell death by apoptosis in human lung epithelial cells

Indium tin oxide (ITO) nanoparticles (NP) have extensive applications in industrial fields, and concerns regarding their potential toxicity in humans and environmental impact have increased. Since exposure to ITO NP is mainly via skin and inhalation, this study was conducted utilizing human lung epithelial (A549) cell line. Cells were exposed to different concentrations of the ITO NP for 24 and 48 hr. A severe cytotoxic response of ITO NP was observed as evident by the (3-4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide and neutral red uptake assays after 48 hr exposure. ITO NP significantly reduced glutathione levels with a concomitant increase in lipid hydroperoxide levels, superoxide activity, and reactive oxygen species (ROS) generation after exposure. A significant induction in caspase activity and formation of condensed chromosomal bodies was also observed after ITO NP (10 or 25 µg/ml) exposure. Furthermore, a significant induction in DNA damage was observed by the Comet assay in cells exposed to ITO NP. Our data demonstrate that ITO NP display cytotoxic and genotoxic potential. However, increase in ROS levels and oxidative stress leading to oxidative DNA damage and condensed chromosomal bodies formation, suggests involvement of apotosis. Thus, ITO NP-mediated effects on cell viability indicate cytotoxicity, and therefore, exposures need to be carefully monitored in the industrial sector.