Self-assembly of gold nanowires along carbon nanotubes for ultrahigh-aspect-ratio hybrids

We report a novel approach for the assembly of one-dimensional hybrid nanostructures that consist of gold nanowires with ultrahigh aspect ratios (L/d > 500) self-assembled along the axes of multiwalled carbon nanotubes. The micrometer-long hybrid nanowires exhibit high electrical conductivity and can be easily microcontact-printed onto various substrates in a patterned form, suggesting that these hybrids have considerable potential as interconnects for nanoelectronic applications.

An exploration of the motivation to attend for spectators of the Lexmark Indy 300 champ car event, Gold Coast

The perceptions of spectators (N = 36) at the Lexmark Indy 300 Champ Car event were assessed via qualitative methods to evaluate their internal and external motivations to attend. The most common reason to attend was the atmosphere that the event created, and entertainment. Other reasons included the race, enjoying the company of friends, and group affiliation. The characteristics of the majority of attendees were predominantly male, 26 to 35 years old, from Queensland, who earned around AUD$50,000 to $75,000 per annum. The findings of the study have implications for sport marketers who wish to communicate to these individuals.

An examination of Australian gold mining firms' exposure over the collapse of gold price in the late 1990s

Purpose – The purpose of this study is to examine the exposures of Australian gold mining firms in the highly volatile period from 1995 to 2000. This period has been characterized by significant changes in gold price due to bulk sale of gold by collective central banks. Specifically, the paper aims to investigate several firm-specific factors that are hypothesized to carry substantial influence on gold beta.

Design/methodology/approach – To estimate gold beta, we use the following multifactor model: R_g,_t = a+ß_gGPR_t + ß_xFXR_t + ß_mR_m,_t + _Et , where R_g,_t is the return on the gold stock Index at time t, GPR_t is the gold price return denominated in US dollar at time t, FXR_t is the foreign exchange return of Australian dollar in terms of US dollar at time t, R_m,t is the market return at time t, and _Et is the random error term at time t.

Findings – The paper finds that the values of gold beta are consistently greater than one, implying the sensitive nature of firms’ stock returns to gold price changes. This also suggests that investors holding gold mining stock would receive higher percentage increases in stock returns from a percentage increase in gold price returns, as opposed to investors holding gold bullion. Furthermore, these values have changed substantially over time with significant changes in gold price volatility. The most important and consistent relationship that we find is the impact of firms’ hedging behavior on their respective gold betas. This is consistent with Tufano’s study. It implies that firms, which hedge a greater proportion of their gold reserves, are less sensitive to movements in gold prices. The finding therefore supports the risk management theory that hedging increases shareholder’s wealth. However, cash operating costs, cash reserves and the level of gold production seem to influence very little on the firms’ exposure to gold price changes.

Originality/value – This study is of interest and important to the stock mining companies and investors because the extent of the effect of gold price movements on the stock returns of gold mining companies has significant impacts on returns for both firms and investors especially in their risk management and investment decisions, respectively.

A comparative assessment of a-lipoic acid N-phenylamides as non-steroidal androgen receptor antagonists both on and off gold nanoparticles

A group of α-lipoic acid N-phenylamides were synthesized employing a variety of amide coupling protocols utilizing electron deficient anilines. These compounds were then assessed for their ability to block androgen-stimulated proliferation of a human prostate cancer cell line, LNCaP. These structurally simple compounds displayed anti-proliferative activities at, typically, 5–20 μM concentrations and were comparable to a commonly used anti-androgen Bicalutamide®. The inclusion of a disulfide (RS-SR) moiety, serving as an anchor to several metal nanoparticle systems (Au, Ag, Fe₂O₃, etc.), does not impede any biological activity. Conjugation of these compounds to a gold nanoparticle surface resulted in a high degree of cellular toxicity, attributed to the absence of a biocompatible group such as PEG within the organic scaffold.

Identification of surface heterogeneity effects in cyclic voltammograms derived from analysis of an individually addressable gold array electrode

Voltammetric behavior at gold electrodes in aqueous media is known to be strongly dependent on electrode polishing and history. In this study, an electrode array consisting of 100 nominally identical and individually addressable gold disks electrodes, each with a radius of 127 µm, has been fabricated. The ability to analyze both individual electrode and total array performance enables microscopic aspects of the overall voltammetric response arising from variable levels of inhomogeneity in each electrode to be identified. The array configuration was initially employed with the reversible and hence relatively surface insensitive [Ru(NH₃)₆]^3+/2+ reaction and then with the more highly surface sensitive quasi-reversible [Fe(CN)₆]^3−/4− process. In both these cases, the reactants and products are solution soluble and, at a scan rate of 50 mV s⁻¹, each electrode in the array is assumed to behave independently, since no evidence of overlapping of the diffusion layers was detected. As would be expected, the variability of the individual electrodesʼ responses was significantly larger than found for the summed electrode behavior. In the case of cytochrome c voltammetry at a 4,4′-dipyridyl disulfide modified electrode, a far greater dependence on electrode history and electrode heterogeneity was detected. In this case, voltammograms derived from individual electrodes in the gold array electrode exhibit shape variations ranging from peak to sigmoidal. However, again the total response was always found to be well-defined. This voltammetry is consistent with a microscopic model of heterogeneity where some parts of each chemically modified electrode surface are electroactive while other parts are less active. The findings are consistent with the common existence of electrode heterogeneity in cyclic voltammetric responses at gold electrodes, that are normally difficult to detect, but fundamentally important, as electrode nonuniformity can give rise to subtle forms of kinetic and other forms of dispersion.

Effect of gold on the corrosion behavior of an electroless nickel/immersion gold surface finish

The performance of surface finishes as a function of the pH of the utilized plating solution was evaluated by electrochemical impedance spectroscopy (EIS) and potentiodynamic polarization tests in 3.5 wt.% NaCl solution. In addition, the surface finishes were examined by x-ray diffraction (XRD), and the contact angle of the liquid/solid interface was recorded. NiP films on copper substrates with gold coatings exhibited their highest coating performance at pH 5. This was attributed to the films having the highest protective efficiency and charge transfer resistance, lowest porosity value, and highest contact angle among those examined as a result of the strongly preferred Au(111) orientation and the improved surface wettability.

Simultaneous synthesis of gold nanoparticles and conducting poly(3,4-ethylenedioxythiophene) towards optoelectronic nanocomposites

In this paper, a new method for obtaining poly(3,4-ethylenedioxythiophene) (PEDOT/PSS)/gold nanocomposites is described. In a first step, PEDOT/PSS gold nanoparticle aqueous dispersions were obtained by simultaneous chemical synthesis of PEDOT and gold nanoparticles in the presence of PSS that acts as a stabilizer. In a second step, these PEDOT/PSS gold nanoparticle dispersions were used to formulate nanocomposites by mixing the initial dispersion with commercially available PEDOT/PSS aqueous dispersion. Nanocomposite thin films, obtained by casting these dispersions, present an intimate contact between the inorganic and organic components

An exploration of the motivation to attend for spectators of the Lexmark Indy 300 champ car event, Gold Coast

The perceptions of spectators (N = 36) at the Lexmark Indy 300 Champ Car event were assessed via qualitative methods to evaluate their internal and external motivations to attend. The characteristics of the majority of attendees who were interviewed for this study were predominantly male, 26–35 years old, from Queensland, and who earned around AUD$50,000–75,000 per annum. The most common reason to attend was the atmosphere that the event created, in particular, the entertainment options. Other reasons included watching the race, the location, living nearby, attending with friends or family and interacting and socializing with other people who also attend. The findings revealed that participants attended to escape every day life, or that they were a ‘true fan’ of the motorsport. The findings of the study have implications for sport marketers who wish to communicate to those individuals in more targeted approaches for a more efficient and effective impact.

X-ray diffraction line broadening from gold and platinum thin films

X-ray diffraction line profile analysis has been used to study the microstructure of (Ill) oriented gold and platinum thin films deposited by thermal evaporation and DC magnetron sputtering. In addition to crystallite size broadening, the profiles from these films displayed broadening arising from dislocations. A parallel investigation, using transmission electron microscopy (TEM) was undertaken to study the nature of dislocations formed, and to provide information on the dimensions of the crystallite columns in the films. X-ray data were collected at room temperature to determine the anisotropy of the broadening with (hkl), using a Siemens D5000 powder diffractometer (CuKa radiation) and two high-resolution synchrotron instruments (BM 16 at the ESRF [A=0.35A] and station 2.3 at the Daresbury laboratory. Two approaches to instrument deconvolution were investigated; Fourier deconvolution and fundamental parameters profile fitting, using Lab6 as a reference material to determine the instrument profile function. After removal of the crystallite size broadening contribution from the measured integral breadths, the residual microstrain broadening was modelled assuming dislocations based on a FCC a/2<110>{ Ill} slip system. The results of the X-ray analysis agreed with dark field TEM micrographs, which showed that many of the crystallites contained dislocations of mixed character (screw- edge).