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Abstract: The recycling of iron bearing dusts produced during iron and steel manufacturing processes is vital to the sustainability of these processes; however, contamination of these dusts with zinc increases the difficulty to do this. Blast furnace dust, collected by a wet scrubber system, was sampled and characterised to investigate the removal of zinc to produce a treated residue with low zinc content suitable for recycling through the blast furnace. This paper examines a leaching process for the dust using different organic carboxylic acids, to establish if they were capable of extracting high levels of zinc and low levels of iron. Prop-2-enoic acid was found to be particularly effective, extracting high levels of zinc up to 85.7% and low levels of iron, 8.5%. The paper also discusses the mechanisms of extraction more specifically for organic carboxylic acids and found that the iron extraction was well explained by the variation in pH and the Bronsted–Lowry theory; whereas zinc extraction was well explained by substituent group effects and the Lewis acid/base theory. The novel use of a non-aqueous solvent with prop-2-enoic acid, to minimise the ion solvating ability and proton dissociation, was found to reduce the level of iron extraction from 8.5% to 0.1% without detrimental effect on zinc extraction when leaching. A range of mineral and carboxylic acids were also tested to investigate and compare the effect of pH and chemical structure on the leaching efficacy. [Copyright &y& Elsevier]

There are at least 100 loci encoding products that influence tip growth and branching in Neurospora crassa. The functional relationships between 38 of these loci were examined by an analysis of gene interaction in double mutants. A complex range of interactions was revealed. These have been grouped into full and partial epistasis, costasis, novel phenotypes, and synthetic lethality and sublethality. Epistasis was used to construct the simplest “pathway” that accommodated the results; this pathway was Y-shaped. If synthetic sublethality is interpreted to reflect mutations in the same pathway, the sublethal connections are compatible with the chart of epistasis. The gene interactions discovered represent candidates for future cell and molecular studies on the interaction of gene products in the control of tip growth and branching. [Copyright &y& Elsevier]

Abstract: Vermicompost was produced from a green waste compost feedstock and assessed for its potential use in a high value horticultural market. Replicated plant growth trials were undertaken with lettuce using pure worm cast (vermicompost), green waste-derived compost and mixtures of the two, i.e. 50/50 (v/v) and 20/80 (v/v) of worm casts and green waste feedstock. Results showed that plant biomass production was optimal with a 20/80 (v/v) compost blend, whilst pure worm cast and green waste compost yielded poor growth. Leaf chlorophyll content indicated that pure worm cast inhibited plant growth and depressed N content, whereas plant grown with the other treatments contained similar amounts of chlorophyll. In general, the vermicomposting process did not result in an increased availability of nutrients or potentially toxic elements, the only exception being Zn. [Copyright &y& Elsevier]

Announces the availability of travel grants for the 19th International Congress of Genetics slated in July 2003 in Melbourne, Australia. Existing state of the art of genetics; Details about the conference; Requirements for the grant of travel bursaries.

Discusses a study that investigated cell death pathway using the ultrastructural changes and internucleosomal DNA fragmentation patterns of senescing kalilo strains of Neurospora. Occurrence of cell death in multicellular organisms; Features of apoptosis; Analysis of DNA fragmentation.

Abstract: Hydrous ferric oxide (here termed ‘ochre’) sludge, an abundant waste product produced from the treatment of acid mine drainage (AMD), was used in this study for the removal of phosphorus (in the form of phosphate ions) from contaminated waters. The phosphorus uptake capacities of both raw and pelletized AMD solids were compared using batch and column tests. Addition of a cement binder to the AMD solids during pellet production led to significantly increased P-loading of the resultant solids compared to the raw sludge. Additionally, the pellets were found to continue to remove P in tests up to 7d in duration whereas the unbound AMD sludge appeared to approach equilibrium with phosphate solution after approximately 60min of contact time. In line with previous studies P uptake by the AMD solids was found to be primarily via adsorption. By contrast calcium phosphate precipitation was found to be the dominant removal mechanism for the cement-bound ochre pellets with a relatively small proportion of removal attributable to the AMD solids. SEM–EDX analysis of the surface of used pellets showed a Ca:P molar ratio close to that of hydroxyapatite (HAP). Continuous column tests on these pellets showed a rapid decrease in P removal capacity by the pellets over time, attributable to the formation of a passivating HAP surface layer. [Copyright &y& Elsevier]