Cadmium stress alters gene expression of DNA mismatch repair related genes in Arabidopsis seedlings

Cadmium (Cd) is a non essential element, and is a widespread environmental pollutant. Exposure to Cd can result in a variety of adverse health effects in plant and humans. In the current study, Arabidopsis seedlings were used as a bio-indicator of Cd pollution. Seedlings were grown on MS media containing 0-6.0 mg L(-1) Cd for 18 days, and the gene expression patterns were used to link increased Cd exposure with progressive biological effects. Reduction of total soluble protein content in shoots of the Arabidopsis seedlings occurred with increase in Cd concentrations. For the gene expression patterns, seven genes known to be involved in cell division and DNA mismatch repair (MMR) system were investigated by semi-quantitative RT-PCR, and normalized using 18S rRNA gene expression. Expression of the proliferating cell nuclear antigen 2 (atPCNA 2), MutS 3 homolog (atMSH 3) and MutL1 homolog (atMLH1) genes in shoots of Arabidopsis was strongly induced by exposure to 0.75 mg L(-1) Cd, but were repressed by other Cd concentrations whereas exposure to 0.75-6 mg L(-1) of Cd resulted in a decreased expression of atPCNA1, atMSH 2, 6 and 7 genes independently of any observable biological effects, including survival, fresh weight and chlorophyll level of shoots. This work demonstrated that specific gene expression changes could serve as useful molecular biomarkers indicative of Cd exposure and related biological effects.     

Assessment of potential health risk for inhabitants living near a former lead smelter. Part 1: metal concentrations in soils, agricultural crops, and homegrown vegetables

Soil contamination by metals engenders important environmental and health problems in northern France where a smelter (Metaleurop Nord) was in activity for more than a century. This study aims to look at the long-term effects of the smelter after its closedown by combining data on the degree of soil contamination and the quality of the crops grown (agricultural crops and homegrown vegetables) in these soils for a better assessment of the local population’s exposure to Cd, Pb, and Zn. Seven years after the Metaleurop Nord closedown, (1) the agricultural and urban topsoils were strongly contaminated by Cd, Pb, and Zn; (2) the kitchen garden topsoils were even more polluted than the agricultural soils, with great variability in metal concentrations within the gardens studied; (3) a high proportion of the agricultural crops for foodstuffs did not conform with the European legislation; (4) for feedstuffs, most samples did not exceed the Cd and Pb legislation limits, indicating that feedstuffs may be an opportunity for most agricultural produce; and (5) a high proportion of the vegetables produced in the kitchen gardens did not conform with the European foodstuff legislation. The high contamination level of the soils studied continues to be a risk for the environment and the population’s health. A further investigation (part 2) assesses the associated potential health risk for local inhabitants through consumption of homegrown vegetables and ingestion of soil particles by estimating the site-specific human health assessment criteria for Cd and Pb.     

Preparation and Characterization of Xylan Derivatives and Their Blends

Although hemicellulose is found widely in nature, it is currently under-utilized as a raw material for commercial applications. It would be desirable to find new uses for hemicellulose in order to add value to this agro-based material. A common type of hemicellulose is xylan, which is found in a number of wood species and in cotton. In this work we prepared cationic and anionic xylan derivatives and characterized them by ¹³C NMR, FT-IR, size exclusion chromatography (SEC), thermal analysis, and rheology. In particular, the ¹³C NMR spectra of carboxymethyl xylan (CMX) and quaternary ammonium-adducted xylan (QAX) were fully assigned with the help of samples with different degrees of substitution. SEC indicated that the beechwood xylan showed a bimodal molecular weight distribution, but with derivatization the distribution tended to become unimodal. Thermal analysis and rheology studies did not uncover any surprises; the solution of xylan and its derivatives exhibited mostly Newtonian behavior. The blends of CMX and QAX produced a precipitate at almost all ratios, indicating the formation of a polyelectrolyte complex. When cationic and anionic xylan samples were added together to paper, the paper dry strength increased. Thus, the combination of cationic/anionic xylan may be of interest in selected applications.     

Integration and implementation of sustainable ICT-based education in developing countries: low-cost,en masse methodology in Kenya

The quality of education in Kenya’s public elementary schools has continued to drop, which is an ironic outcome in the wake of the introduction of tuition-exempt primary education. This removal of tuition costs led to a surge in primary education enrollment that overwhelmed the existing educational infrastructure. Overcapacity in classrooms led to frustrated teachers and mediocre delivery of content amid the overstretched resources and limited education budget. To remedy this situation, the government has begun introducing various information and communication technologies (ICTs) in schools to supplement current resources. This comes with mixed results. This paper aims to demonstrate effective strategies for integrating low-cost ICT-based materials in schools in developing countries through a community of practice. Three schools were used to illustrate integration of sustainable ICT-based education in a style of classroom characteristic in developing schools. Development and use of prerecorded DVD-based content was proposed as an effective solution. A comparative study was undertaken to evaluate the differences in student comprehension and educator delivery of education involving a digital, ICT-integrated classroom and a traditional, analog-type teaching method classroom to underscore the empirical evidence of the effectiveness of introducing a low-cost ICT-based program. This study also shows that teachers are better positioned to lead the design and development of appropriate and innovative materials. Furthermore, to cope with the immense amount of materials that need developing to correspond with the curriculum, it shows that with the emergence of a community of practice of teachers, many suitable low-cost materials can be developed. This takes place through an iterative collaboration as opposed to traditional top-down approaches, which have a proven record of failure.     

Integrated management of ash from industrial and domestic combustion: a new sustainable approach for reducing greenhouse gas emissions from energy conversion

Environmental Science and Pollution Research - This work supports, for the first time, the integrated management of waste materials arising from industrial processes (fly ash from municipal solid...     

Bioaccessibility of trace elements as affected by soil parameters in smelter-contaminated agricultural soils: a statistical modeling approach

An investigation was undertaken to identify the most significant soil parameters that can be used to predict Cd, Pb, and Zn bioaccessibility in smelter-contaminated agricultural soils. A robust model was established from an extended database of soils by using: (i) a training set of 280 samples to select the main soil parameters, to define the best population to be taken into account for the model elaboration, and to construct multivariate regression models, and (ii) a test set of 110 samples to validate the ability of the regression models. Total carbonate, organic matter, sand, P(2)O(5), free Fe-Mn oxide, and pseudototal Al and trace element (TE) contents appeared as the main variables governing TE bioaccessibility. The statistical modeling approach was reasonably successful, indicating that the main soil factors influencing the bioaccessibility of TEs were taken into account and the predictions could be applicable for further risk evaluation in the studied area.     

The Efficacy of a Programme of Landslide Risk Reduction in Areas of Unplanned Housing in the Eastern Caribbean

Poor countries are disproportionately affected by the cost of disasters. Yet there is evidence of the benefits of seeking to mitigate the impact of a disaster, compared with the costs incurred in ‘making good’ after a major event has occurred. This article reviews a programme of landslide risk reduction in unplanned communities in the Eastern Caribbean. The construction of appropriate surface water management measures, based on the application of scientific and engineering principles, has been demonstrated to reduce the hazard from rainfall-triggered landslides. Adopting a community-based approach additionally delivers social and environmental benefits relating to employment generation, improvements in the environmental conditions within the community, and improvements slope management practices. The sustained implementation of the community-based projects has provided the necessary evidence-base for these practices to influence Government policy and practice, and gain recognition from regional development agencies. The strategic and incremental uptake of the community-based methodology is demonstrated to be an effective means for delivering physical landslide risk reduction measures in the most ‘at risk’ areas of unplanned housing.     

Bioaccumulation of perfluoroalkyl acids in dairy cows in a naturally contaminated environment

Beef and dairy products may be important vectors of human exposure to perfluoroalkyl acids (PFAAs), but the understanding of how PFAAs are accumulated and transferred through agricultural food chains is very limited. Here, the bioaccumulation of PFAAs in dairy cows receiving naturally contaminated feed and drinking water was investigated by conducting a mass balance of PFAAs for a herd of dairy cows in a barn on a typical Swedish dairy farm. It was assumed that the cows were able to reach steady state with their dietary intake of PFAAs. Perfluorooctane sulfonic acid (PFOS) and perfluoroalkyl carboxylic acids (PFCAs) with 8 to 12 carbons were detected in cow tissue samples (liver, muscle, and blood) at concentrations up to 130 ng kg^?1. Mass balance calculations demonstrated an agreement between total intake and excretion within a factor of 1.5 and consumption of silage was identified as the dominant intake pathway for all PFAAs. Biomagnification factors (BMFs) were highly tissue and homologue specific. While BMFs of PFOS and PFCAs with 9 and 10 fluorinated carbons in liver ranged from 10 to 20, perfluorooctanoic acid (PFOA) was not biomagnified (BMF?<?1) in any of the investigated tissues. Biotransfer factors (BTFs; defined as the concentration in tissue divided by the total daily intake) were calculated for muscle and milk. Log BTFs ranged from ?1.95 to ?1.15 day kg^?1 with the highest BTF observed for PFOS in muscle. Overall, the results of this study suggest that long-chain PFAAs have a relatively high potential for transfer to milk and beef from the diet of dairy cows. However, a low input of PFAAs to terrestrial systems via atmospheric deposition and low bioavailability of PFAAs in soil limits the amount of PFAAs that enter terrestrial agricultural food chains in background contaminated environments and makes this pathway less important than aquatic exposure pathways. The BTFs estimated here provide a useful tool for predicting human exposure to PFAAs via milk and beef under different contamination scenarios.     

Comparison of Wind at 500 Feet Over Minneapolis and Louisville With Geostrophic Wind

Measurements of wind speed at 500 ft on a television tower in the Minneapolis-St. Paul area are compared with geostrophic wind speeds and lapse rates. The roughness length for the builtr-up area surrounding the tower is estimated using geostrophic boundary-layer models. Similar data for Louisville are also considered. The results are relevant to-the application of existing boundary-layer models to the estimation of wind speed and turbulent mixing over a city.