The synthesis, characterization, and catalytic ability of gold/bismuth (Au/Bi) core/shell nanocrystals for promoting asymmetric 1D nanowire growth is described. A biphasic gold reduction approach is initially used to create small (∼1.5 nm diameter) Au particles passivated with trioctylphosphine (TOP). The alkylphosphine ligands render the Au nanocrystals soluble in common organic solvents used for II-VI semiconductor nanocrystal/nanorod growth. Subsequent surface passivation with elemental bismuth is accomplished through the thermolysis of trialkylbismuthines at 100 °C in a mildly coordinating solvent. The resulting core/shell particles are characterized by using a variety of techniques including transmission electron microscopy (TEM), X-ray diffraction (XRD), and energy-dispersive X-ray spectroscopy (EDXS) to demonstrate successful overcoating of the Au nanoparticles. Resulting diameters range from 1.43 to 2.53 nm, with the as-made Au/Bi nanocrystals stable for weeks to months when stored at low temperature under an inert atmosphere. Catalytic activity, promoting the asymmetric growth of II-VI semiconductor nanowires, is demonstrated for the particular case of CdSe, illustrating a relatively simple route for making high-quality, narrow-diameter (<10 nm) 1D materials capable of exhibiting quantum confinement.

Efficacy of Gd-DTPA and Gd-DOTA as GdNCT agents is predicted to be low, due to the insufficient number of tumor cell nuclei incorporating Gd. Although multiple administration schedules in vivo might induce Gd penetration into more tumor cell nuclei, a search for new Gd compounds with higher nuclear affinity is warranted before planning GdNCT in animal models or clinical trials.

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We present chemical mapping of all physiologically relevant elements at the subcellular level, as well as the trace element Gd. A broad energy range (60-1200 eV) is fundamental to investigate a)) the elements in the same microscopic locations. Concentrated elements (> 100 ppm) can be simply mapped by image ratio, while dilute species must be treated with gréât care to avoid artifacts. We propose a new method to obtain location maps of trace elements.