2 results for Al-Salim, N

  • Quantum dot transport in soil, plants, and insects.

    Malone, Louise; Al-Salim, N; Clothier, B; Burgess, E; Barraclough, E; Green, S; Weir, G; Deurer, M (2011)

    Journal article
    The University of Auckland Library

    Environmental risk assessment of nanomaterials requires information not only on their toxicity to non-target organisms, but also on their potential exposure pathways. Here we report on the transport and fate of quantum dots (QDs) in the total environment: from soils, through their uptake into plants, to their passage through insects following ingestion. Our QDs are nanoparticles with an average particle size of 6.5 nm. Breakthrough curves obtained with CdTe/mercaptopropionic acid QDs applied to columns of top soil from a New Zealand organic apple orchard, a Hastings silt loam, showed there to be preferential flow through the soil's macropores. Yet the effluent recovery of QDs was just 60%, even after several pore volumes, indicating that about 40% of the influent QDs were filtered and retained by the soil column via some unknown exchange/adsorption/sequestration mechanism. Glycine-, mercaptosuccinic acid-, cysteine-, and amine-conjugated CdSe/ZnS QDs were visibly transported to a limited extent in the vasculature of ryegrass (Lolium perenne), onion (Allium cepa) and chrysanthemum (Chrysanthemum sp.) plants when cut stems were placed in aqueous QD solutions. However, they were not seen to be taken up at all by rooted whole plants of ryegrass, onion, or Arabidopsis thaliana placed in these solutions. Leafroller (Lepidoptera: Tortricidae) larvae fed with these QDs for two or four days, showed fluorescence along the entire gut, in their frass (larval feces), and, at a lower intensity, in their haemolymph. Fluorescent QDs were also observed and elevated cadmium levels detected inside the bodies of adult moths that had been fed QDs as larvae. These results suggest that exposure scenarios for QDs in the total environment could be quite complex and variable in each environmental domain.

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  • Novel coordination in the first tellurium porphyrin complex: Synthesis and crystal structure of [Te(ttp)Cl-2]

    Grubisha, DS; Guzei, IA; Al-Salim, N; Boyd, Peter; Brothers, Penelope; Woo, LK (2001)

    Journal article
    The University of Auckland Library

    Despite the wealth of fundamental and applied research on porphyrin complexes of the metallic elements, non-metal porphyrin complexes have been much less extensively studied.[1] Porphyrin complexes of the groups 13 ± 15 elements are well-established, but as yet no porphyrin complex of any group 16 element is known. ...

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