DNA and chromosomal damage in response to intermittent extremely low-frequency magnetic fields.

Considerable controversy still exists as to whether electric and magnetic fields (MF) at extremely low frequencies are genotoxic to humans. The aim of this study was to test the ability of alternating magnetic fields to induce DNA and chromosomal damage in primary human fibroblasts. Single- and double-strand breaks were quantified using the alkaline comet assay and the gammaH2AX-foci assay, respectively. Chromosomal damage was assayed for unstable aberrations, sister chromatid exchange and micronuclei. Cells were exposed to switching fields - 5min on, 10min off - for 15h over the range 50-1000microT. Exposure to ionizing radiation was used as a positive-effect calibration. In this study two separate MF exposure systems were used. One was based on a custom-built solenoid coil system and the other on a commercial system almost identical to that used in previous studies by the EU REFLEX programme. With neither system could DNA damage or chromosomal damage be detected as a result of exposure of fibroblasts to switching MF. The sensitive gammaH2AX assay could also not detect significant DNA damage in the MF-exposed fibroblasts, although the minimum threshold for this assay was equivalent to an X-ray dose of 0.025Gy. Therefore, with comparable MF parameters employed, this study could not confirm previous studies reporting significant effects for both the alkaline and neutral comet assays and chromosomal aberration induction.

Microbeam studies of the bystander response.

Microbeams have undergone a renaissance since their introduction and early use in the mid 60s. Recent advances in imaging, software and beam delivery have allowed rapid technological developments in microbeams for use in a range of experimental studies. The resurgence in the use of microbeams since the mid 90s has coincided with major changes in our understanding of how radiation interacts with cells. In particular, the evidence that bystander responses occur, where cells not directly irradiated can respond to irradiated neighbours, has brought about the evolution of new models of radiation response. Although these processes have been studied using a range of experimental approaches, microbeams offer a unique route by which bystander responses can be elucidated. Without exception, all of the microbeams currently active internationally have studied bystander responses in a range of cell and tissue models. Together these studies have considerably advanced our knowledge of bystander responses and the underpinning mechanisms. Much of this has come from charged particle microbeam studies, but increasingly, X-ray and electron microbeams are starting to contribute quantitative and mechanistic information on bystander effects. A recent development has been the move from studies with 2-D cell culture models to more complex 3-D systems where the possibilities of utilizing the unique characteristics of microbeams in terms of their spatial and temporal delivery will make a major impact.

Development of a monoclonal antibody binding okadaic acid and dinophysistoxins-1, -2 in proportion to their toxicity equivalence factors

Okadaic acid (OA) and structurally related toxins dinophysistoxin-1 (DTX-1), and DTX-2, are lipophilic marine biotoxins. The current reference method for the analysis of these toxins is the mouse bioassay (MBA). This method is under increasing criticism both from an ethical point of view and because of its limited sensitivity and specificity. Alternative replacement methods must be rapid, robust, cost effective, specific and sensitive. Although published immuno-based detection techniques have good sensitivities, they are restricted in their use because of their inability to: (i) detect all of the OA toxins that contribute to contamination; and (ii) factor in the relative toxicities of each contaminant. Monoclonal antibodies (MAbs) were produced to OA and an automated biosensor screening assay developed and compared with ELISA techniques. The screening assay was designed to increase the probability of identifying a MAb capable of detecting all OA toxins. The result was the generation of a unique MAb which not only cross-reacted with both DTX-1 and DTX-2 but had a cross-reactivity profile in buffer that reflected exactly the intrinsic toxic potency of the OA group of toxins. Preliminary matrix studies reflected these results. This antibody is an excellent candidate for the development of a range of functional immunochemical-based detection assays for this group of toxins.

Adsorption Characteristics of Reactive Dyes in Columns of Activated Carbon

Abstract: Adsorption behaviour of reactive dyes in fixed-bed adsorber was evaluated in this work. The characteristics of mass transfer zone (MTZ), where adsorption in column occurs, were affected by carbon bed depth and influent dye concentration. The working lifetime (t(x)) of MTZ, the height of mass transfer zone (HMTZ), the rate of mass transfer zone (RMTZ), and the column capacity at exhaustion (q(column)) were estimated for the removal of remazol reactive yellow and remazol reactive black by carbon adsorber. The results showed that column capacity calculated at 90% of column exhaustion was lower than carbon capacity obtained from equilibrium studies. This indicated that the capacity of activated carbon was not fully utilized in the fixed-bed adsorber. The bed-depth service time model (BDST) was applied for analysis of reactive yellow adsorption in the column. The adsorption capacity of reactive yellow calculated at 50% breakthrough point (No) was found to be 0.1 kg kg(-1) and this value is equivalent to about 14% of the available carbon capacity. The results of this study indicated the applicability of fixed-bed adsorber for removing remazol reactive yellow from solution. (C) 2008 Elsevier B.V. All rights reserved.

A simple chemical free arsenic removal method for community water supply - A case study from West Bengal, India

This report describes a novel technology for arsenic removal from groundwater. The work was carried out in India in collaboratio with three Indian and three European partners. European partners include Leiden University of the Netherlands and Stuttgart University of Germany. The work was funded by The World Bank.