2008, in Stockholm, Sweden. The congress, which is a successor to the former INVITOX workshops, attracted more than 270 participants from 33 countries, to discuss recent developments in in vitro toxicology. The first session considered the use of embryonic stem cells in developmental toxicology. Martina Klemm (ProteoSys, Mainz, Germany) described several European initiatives, including ReProTect, ESNATS (Embryonic Stem-cell based Novel Alternative Testing Strategies), and the EU-funded Framework 6 and 7 Programmes, and considered the challenges faced by toxicologists with regard to the standardisation of methodologies. Nobuyki Horie (Sumitomo Chemical Co., Osaka, Japan) considered the validation process further, describing how data from murine embryonic stem cell tests and from various endpoint studies with 3T3 cells, could be used to assist with protocol refinement, classification, and weight-of-evidence validation of the EST. Sarah Adler (ZEBET, Berlin, Germany) introduced a set of biomarkers for pluripotency and cardiomyocyte differentiation, which may be useful as a means of obtaining quantitative measurements for toxicological assessments. The final two speakers in this session, Gunnar Carlsson (Swedish University of Agri cultural Sciences, Uppsala, Sweden) and Kaja Skaerven (National Institute of Nutrition and Seafood Research [NIFES], Bergen, Norway) looked at fish as a source of embryonic stem cells, with a particular focus on aquatic toxicity. This was a useful lead into the second session, where in vitro models of aquatic toxicity were considered in greater depth. Kristin Schirmer (Swiss Federal Institute of Aquatic Science and Technology [Eawag], Düben dorf, Switzerland) reiterated the most important reason why alternatives are needed for this toxicological endpoint — namely, that the current OECD test guideline for acute toxicity still requires lethality as an endpoint, even though a test based on zebrafish embryos is already being used by the German authorities for waste-water testing. During the remainder of this session, a range of topics were covered, including the assessment of hormone activity in surface waters, and the evaluation of environmental toxicity by proteomics. Sessions 3 and 4 considered tests to ascertain topical toxicity, and the ability of chemicals to induce allergic responses by using various in vitro models, including lung slices, organotypic human epidermis and corneal models, and cell-based systems. Gavin Maxwell (Unilever, Sharnbrook, UK) focused on new approaches for assessing skin sensitisation potential, by looking at ‘omics’-based sources of information and computer-based analyses, including pathway analysis. Jef Hooyberghs (VITO, Mol, Belgium) gave a detailed breakdown of gene expression data, which show how a dendritic cell-based system (VITOSENS®) can discriminate between sensitisers and non-sensitisers. Sandra Szameit (Austrian Research Centers [ARC], Seibersdorf, Austria) also described a dendritic cell system, and showed the expression profiles of 6 genes to predict sensitisation potential during a cell-based assay conducted over a 24-hour exposure duration, in which cytotoxicity could be confidently removed from consideration. Another talk given in Session 3, by Heléne Lindergren (University of Stockholm, Stockholm, Sweden), introduced a potentially useful in vitro test that involves the use of an engineered neuroblastoma cell line, SH-SY5Y, to discriminate surfactants found in hygiene products, which are capable of triggering a pain response. This test relies on measuring the receptor-mediated release of intracellular calcium as a quantifiable endpoint, and may prove more reliable than assessing clinical discomfort in animal models, such as the rabbit. The natural progression from considering how data from ‘omics’ and other new technology platforms can be incorporated into toxicity testing, is to see how such approaches can assist with method evaluation and how the experimental data produced can be extrapolated back to the target organism. Several talks in Session 4 considered these questions. Roland Grafström (Karolinska Institute, Stockholm, Sweden) looked at the use of bioinformatics and pathway analysis to evaluate the capabilities of cell lines. One particularly interesting aspect was the discussion of how biomarkers detected in cell-based studies could be related to those found in saliva, since this may prove useful for the early detection of mouth cancers. The impact of the metabolic competence of in vitro test systems on their usefulness for toxicity testing, was considered in the next session. Olavi Pelkonen and Khaled Abss (University of Oulu, Oulu, Finland) presented data that indicated the ATLA 36, 723–728, 2008 723
AbstractThe dependence of the pitting potential Ep of 1018 carbon steel on chloride concentration, pH and the temperature of the solution was studied by the potentiodynamic method in accordance with a statistical experimental design. The parameters of the empirical pitting potential model determined on the basis of Box-W ilson ex perimental design method were evaluated using the experimental data. Comparison of the predicted values from the model with the observed values showed that the model is a good fit. From the model equation the most noble pitting potential value of -225 mV (SCE) was obtained when the Cl- ion concentration, temperature and pH of the solution were 205 ppm, 25°C, and 6·4, respectively. The Box-Wilson experimental design technique was proved to be applicable in modelling the pitting potential of carbon steel.
An investigation has been carried out to assess the zinc runoff from a variety of galvanised materials over 16 months at the industrial/marine Port Talbot weathering site. Over 16 months of exposure, bare zinc, and Electrozinc have the highest levels of Zinc runoff (4.38 and 4.20 g m(-2)) followed by general galvanised steel substrates, i.e. hot dip galvanised (HDG) steel (0.15 wt-%Al) (2.87 g M-2) and iron zinc intermetallic galvanised steel (galvanneal, 2.36 g m(-2)). Galvanneal (IZ) has a higher initial runoff rate than HDG due to the presence of iron/zinc intermetallic in the coating that promotes anodic zinc dissolution. The HDG has a more constant runoff rate that exceeds IZ after 7-8 months due to build up of corrosion products on the IZ surface. Aluminium/zinc alloy coated steels have a much lower runoff rate than general galvanised materials as the aluminium present in the structure provides a strongly protective oxide barrier coating improving corrosion resistance (Galfan 5 wt-%Al, 2.04 g m(-2), and Zalutite 55 wt- %Al, 0.67 g m(-2)). Organically coated steels show relatively little zinc runoff (<0.25 g m(-2)) indicating their effectiveness in preventing surface corrosion. Runoff levels measured do not exceed permissible levels of zinc for drinking water and the measured zinc runoff levels pose little threat to organisms if leached into soil. Using an accelerated laboratory test in which distilled water is sprayed onto specimen panels in a recirculatory system for 100 It a good correlation can be obtained with external exposure,for up to 6 months exposure. For 12 months exposure it-on zinc intermetallic galvanising (galvanneal) begins to become covered in a protective oxide to layer, which cannot form under the conditions of the accelerated test. Despite this, the fit for most specimen types is excellent. Where the predictive test fails is when the galvanising to layer is breached revealing an efficient iron cathode site. This occurs first for electrocoated zinc after 16 months exposure. Similar predictive results can be obtained using a scanning vibrating electrode technique (SVET) in a semiquantitative manner and an immersion electrolyte of 0.1 wt-%NaCl. Again the predictions are initially very accurate but following 12 months exposure the fit for specimens of electrozinc is poor due to the breaching of the galvanising layer.
A potentiostatic weight loss technique has been used to compare the corrosion rates of Weldox 700 high strength low alloy steel exposed to both natural and sterile sea water at potentials ranging,from the free corrosion condition to -1000 m V(SCE). Anodic polarisation curves with Tafel constants of 54 and 64 mV per decade were fitted to the data and the minimum levels of protection required to limit the corrosion rate to 0.001 mm per year were found to be -770 and -790 mV (SCE) in natural and sterile sea water, respectively. Lower corrosion rates occurred in filtered natural sea water than in sterile sea water but the highest rates were recorded on specimens exposed to a seabed sediment. The reasons for this behaviour are discussed in terms of the biofilms and the numbers of sulphate reducing bacteria present on the surfaces.
National composites network Patricia Hewitt, Trade and Industry Secretary, has announced that a £30 million network is to be established to transfer new composites technologies to the aerospace, automotive and other industries. The National Composites Network will bring together industry experts, share knowledge in composites across industries and companies and support SMEs with access to experts, R&D and introduction of new technologies. TWI will take a major role in managing the overall network and will also open a new TWI NDT Validation Centre in Port Talbot, Wales. Speaking at the Farnborough Airshow, Patricia Hewitt said: The Composites Network will be an invaluable tool for companies working across sectors from aerospace to construction. We have some of the best manufacturers in the world here and the Government is committed to supporting innovative technologies in the UK to maintain their success. Further information from: TWI, tel. z44 (0)1223 891162, email composites@twi.co.uk, Internet www. twi.co.uk.
