Significant Associations Between Sun Exposure and Adiposity Were Not Observed in Breast and Prostate Cancer Patients in a Cross‐sectional Analysis

Obesity is a significant health problem worldwide. Exposure to low‐dose ultraviolet radiation (like that in sunlight) suppresses the development of obesity in mice; however, the nature of the associations between sun exposure and adiposity is not well understood in humans. The present study characterized cross‐sectional relationships between sun exposure and adiposity in a convenience cohort of breast (n = 269; mean age = 58 years) and prostate (n = 78; mean age = 69 years) cancer patients. Participants were enrolled in a 3‐month exercise program in Perth, Australia. Self‐reported questionnaires measured time spent outdoors (previous week, winter and summer), sex, age, treatment received and physical activity levels. Adiposity measures included body mass index, waist‐hip ratio and body fat percentage (measured via DXA). In unadjusted models, greater time spent outdoors across all times was significantly associated with lower waist‐hip ratio, while greater time spent outdoors in the last winter was associated with lower body fat percentage, but not when stratified by sex. There were no statistically significant associations between time spent outdoors and adiposity after adjusting for sex, age, treatments received and physical activity. Longitudinal studies in larger populations may elucidate significant associations not found in our study due to the cross‐sectional design and power limitations.     

The determination of mode I stress-intensity factors by holographic interferometry

The use of linear elastic fracture mechanics generally depends upon the availability of suitable analytical or numerical solutions for the relevant crack-tip stress-intensity factor,K. Convenient experimental verification of such solutions is a valuable aid to their correct application and can provide a practical substitute in real design situations of great complexity. A convenient, new experimental technique for estimating the Mode I stress-intensity factor using holographic interferometry and test pieces cut from thin sheets of commercially available polymethylmethacrylate is described and demonstrated. The test pieces can readily be prepared to model any desired Mode I geometry and boundary conditions. In addition, a prior self-calibration procedure can be employed to enhance both convenience and accuracy. Real-time interference-fringe data from the crack-tip region are easily reduced and plotted to yield a straight line whose slope provides a one-parameter evaluation of the effect of geometry on the stress-intensity factor. This information, together with the crack length and applied stress, completely definesK.     

On caustics associated with horizontal rays and vertical modes

Wave propagation in a medium with slowly varying inhomogeneities can sometimes be modelled by a combination of normal mode theory in one direction and ray theoretical methods in the other directions. Caustics can occur in the ray theory ansatz. Here we consider those caustics using a Lagrange manifold approach.     

A new and simple method for the synthesis of highly functionalised pyrrolizidines, indolizidines and pyrroloazepines

The reaction of 5-, 6- and 7-membered cyclic thioimidates with cyclopropenones gives access to highly functionalised pyrrolizidines, indolizidines and pyrroloazepines via a formal [3+2] cycloaddition process.     

Scanning tunneling microscopy-based replacement lithography on self-assembled monolayers: comparison of gold, palladium, and platinum substrates

Self-assembled monolayers of dodecanethiol on gold, palladium, and platinum can be locally replaced with a different thiol under the action of a scanning tunneling microscopy tip at elevated bias. This process is characterized and the bias dependence of the degree of replacement for each metal substrate is illustrated. Replacement on gold substrates occurs at lower applied potentials than on platinum substrates, provided care has been taken to remove surface oxides.     

Effect of low intensity laser interaction with human skin fibroblast cells using fiber-optic nano-probes

Over the past forty years, many efforts have been devoted to study low power laser light interactions with biological systems. Some of the investigations were performed in-vitro, on bulk cell populations. Our present work was undertaken to apply specially engineered fiber-optic based nano-probes for the precise delivery of laser light on to a single cell and to observe production of low power laser light induced reactive oxygen species (ROS). A normal human skin fibroblast (NHF) cell line was utilized in this investigation and the cells were irradiated under two different schemes of exposure: (1) an entire NHF cell population within a Petri dish using a fan beam methodology, and (2) through the precise delivery of laser energy on to a single NHF cell using fiber-optic nano-probe. Photobiostimulative studies were conducted through variation of laser intensity, exposure time, and the energy dose of exposure. Laser irradiation induced enhancement in the rate of cell proliferation was observed to be dependent on laser exposure parameters and the method of laser delivery. The total energy dose (fluence) had a greater influence on the enhancement in the rate of cellular proliferation than compared to laser intensity. The enhancement in the growth rate was observed to have a finite life-time of several days after the initial laser exposure. Fluorescent life-time imaging of ROS was performed during the nano-based single cell exposure method. The kinetics of ROS generation was found to depend strongly on the laser fluence and not on the laser intensity.     

The independent set perturbation adjoint method: A new method of differentiating mesh‐based fluids models

A new scheme for differentiating complex mesh‐based numerical models (e.g. finite element models), the Independent Set Perturbation Adjoint method (ISP‐Adjoint), is presented. Differentiation of the matrices and source terms making up the discrete forward model is realized by a graph coloring approach (forming independent sets of variables) combined with a perturbation method to obtain gradients in numerical discretizations. This information is then convolved with the ‘mathematical adjoint’, which uses the transpose matrix of the discrete forward model. The adjoint code is simple to implement even with complex governing equations, discretization methods and non‐linear parameterizations. Importantly, the adjoint code is independent of the implementation of the forward code. This greatly reduces the effort required to implement the adjoint model and maintain it as the forward model continues to be developed; as compared with more traditional approaches such as applying automatic differentiation tools. The approach can be readily extended to reduced‐order models. The method is applied to a one‐dimensional Burgers' equation problem, with a highly non‐linear high‐resolution discretization method, and to a two‐dimensional, non‐linear, reduced‐order model of an idealized ocean gyre. Copyright © 2010 John Wiley & Sons, Ltd.