The water solubilization of nanoparticles is key for many applications in biomedicine. Despite the importance of surface functionalization, progress has been largely empirical and very few systematic studies have been performed. Here we report on the water solubilization of QDs using lipid encapsulation. We systematically evaluate the monodispersity, zeta potential, stability, and quantum yield (QY) for QDs encapsulated with single and double acyl chain lipids, pegylated double acyl chain lipids, and single alkyl chain surfactant molecules with charged head groups. We show that charged surfactants and pegylated lipids are important to obtain monodisperse suspensions with high yield and excellent long-term stability.

A method is described for using apical sections of Avena coleoptiles grown in the dark for 70 hours as an assay for IAA and for potential precursors of IAA. The experiments were carried out under as sterile conditions as possible.Tryptophan appeared not to act as a precursor of IAA. Tryptamine however showed a marked stimulation of growth indicating its possible conversion to IAA. Other compounds that stimulated growth and hence may be regarded as potential precursors of IAA were anthranilic acid and indole. Kynurenine and shikimic acid were among those without an effect. A hypothetical route for the biogenisis of IAA is suggested based on the findings of this work.

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Significant heat is generated by underground trains, particularly when braking, stopping at platforms and accelerating away from stations. A complex ventilation system including shaft, fans and under-platform extraction thus has to be designed to manage the rising temperature in tunnels and stations. This conventional approach results in high energy consumption for running the fans and neglects the possibility to use the extracted heat above ground in buildings. Lining underground rail tunnels with heat-exchange segments can provide an alternative solution to cool the tunnels and surrounding ground, and transfer the harvested heat to adjacent buildings for heating. It will also bring benefits in terms of reduction of energy consumption for tunnel ventilation operations. This paper reports on the work carried out in designing thermal energy segments for use on the tunnelled sections of the Crossrail project in London, UK.