The controlled fabrication and geometry tunable optics of gold nanotube arrays.

Arrays of vertically aligned gold nanotubes are fabricated over several square centimetres which display a geometry tunable plasmonic extinction peak at visible wavelengths and at normal incidence. The fabrication method gives control over nanotube dimensions with inner core diameters of 15-30 nm, wall thicknesses of 5-15 nm and nanotube lengths of up to 300 nm. It is possible to tune the position of the extinction peak through the wavelength range 600-900 nm by varying the inner core diameter and wall thickness. The experimental data are in agreement with numerical modelling of the optical properties which further reveal highly localized and enhanced electric fields around the nanotubes. The tunable nature of the optical response exhibited by such structures could be important for various label-free sensing applications based on both refractive index sensing and surface-enhanced Raman scattering.

Polarization conversion through collective surface plasmons in metallic nanorod arrays.

For two-dimensional (2D) arrays of metallic nanorods arranged perpendicular to a substrate several methods have been proposed to determine the electromagnetic near-field distribution and the surface plasmon resonances, but an analytical approach to explain all optical features on the nanometer length scale has been missing to date. To fill this gap, we demonstrate here that the field distribution in such arrays can be understood on the basis of surface plasmon polaritons (SPPs) that propagate along the nanorods and form standing waves. Notably, SPPs couple laterally through their optical near fields, giving rise to collective surface plasmon (CSP) effects. Using the dispersion relation of such CSPs, we deduce the condition of standing-wave formation, which enables us to successfully predict several features, such as eigenmodes and resonances. As one such property and potential application, we show both theoretically and in an experiment that CSP propagation allows for polarization conversion and optical filtering in 2D nanorod arrays. Hence, these arrays are promising candidates for manipulating the light polarization on the nanometer length scale.

A survey of skin disease among patients in an Australian nursing home.

UNLABELLED: Although the number of nursing homes is increasing in Australia, few studies have investigated the dermatologic condition of their patients. To address this issue, we conducted one of the first skin disease investigations of nursing home residents in Queensland, Australia. METHODS: Our predominant data source was the attending physicians' medical reports, which are updated monthly following their physical examination of each patient. Specialist podiatrists' monthly progress notes were also used as were daily nursing reports. RESULTS: Just over half the patients (54.4%) had at least one skin disease registered among their medical records. Xerosis (dry skin) was the most common affliction, affecting 29.5% of the patients, followed by onychomycosis (tinea unguium) at 22.5% and dermatitis (8.9%). Skin cancer was recorded in 4.9%, while excoriation (3.1%) and unspecified keratosis (2.2%) were slightly less common. Being bedridden was identified as a risk factor for both xerosis (OR 3.9, 95% CI 1.8-8.7) and onychomycosis (OR 18.0, 95% Cl 7.5-49.0). CONCLUSION: Overall, our research suggests that skin diseases are reasonably common among Australian nursing home patients. The presence of certain dermatologic conditions differed from other reports.