Gold sphere

Hollow gold spheres or core-shell particles consisting of a gold shell on a core of some other material have recently attracted attention. This is because they have interesting and tunable optical extinction properties [56]. These can be readily calculated using Mie theory [57], and there had been some scattered early interest in these shapes as a result [58, 59], but the versatility and properties of these particles only became widely... 

Figure 7.8 Optical properties of solid gold spheres of indicated diameters, (a) absorption, (b) scattering. Redrawn from Cortie et a. [118], Copyright (2005) Society of Photo-Optical Instrumentation Engineers.

Figure 17.3 Anatomy of a redox enzyme representation of the X-ray crystallographic structure of Trametes versicolor laccase III (PDB file IKYA) [Bertrand et al., 2002]. The protein is represented in green lines and the Cu atoms are shown as gold spheres. Sugar moieties attached to the surface of the protein are shown in red. A molecule of 2,5-xyhdine that co-crystallized with the protein (shown in stick form in elemental colors) is thought to occupy the broad-specificity hydrophobic binding pocket where organic substrates ate oxidized by the enzyme. Electrons from substrate oxidation are passed to the mononuclear blue Cu center and then to the trinuclear Cu active site where O2 is reduced to H2O. (See color insert.)...

Figure 17.5 The protein environment around the Cu centers (gold spheres) of laccase from Melanocarpus albomyces (PDB file IGWO) showing a substrate O2 molecule bound in the trinuciear Cu site [Hakulinen et al., 2002], The protein is depicted in stick representation with atoms in their conventional coloring. (Courtesy of Armand W. J. W. Tepper.) (See color insert.)...

If these precautions are not taken, the gold spheres will adhere to the side vessel walls which is evidenced by a red coloration of the glass... 

There are three stages in the production of gold probes 1) production of gold spheres, 2) estimation of the amount of protein to be... 

A 10-p.m gold sphere (p = 19.3 g/cm3) is dropped from a 10-ft-high platform. Estimate the time it takes to strike the ground (a) neglecting air resistance and (6) including air resistance. 

FIG. 8 Experimentally measured repulsive van der Waals interactions between a gold sphere and a smooth poly(tetrafluoroethylene) surface for two different solvents, (a) />-xylene A and (b) bromoben/ene. The data is represented in the form suggested in the text using Eq. (14). The measured Humuker constants for these systems was very similar (ea. 6 x 10 J). In the former diagram the ratio of k/u is ea. 9 kN m... 

The situation is similar in the case of a gold sphere, because the radiative (and local field) enhancements remain small compared to A/.j., for... 

Experience has shown that the desired routine sizes are 5, 10, and 15 nm. All these are useful for transmission electron microscope studies and the 5 nm gold is recommended for light microscopy. Gold spheres of 30 nm are occasionally used for scanning electron microscope immunocytochemistry. A1 nm probe is available and might be useful for both light and electron microscopy after silver enhancement. 

Figure 10. Gold spheres (15 and 9 m) adhering to an anthracene substrate ...

Names gold powder, gold flakes, gold spheres... 

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