DNA-Mediated Electrochemistry

The base pair stack of DNA has been demonstrated as a medium for long-range charge transport chemistry both in solution and at DNA-modified surfaces. This chemistry is exquisitely sensitive to structural perturbations in the base pair stack as occur with lesions, single base mismatches, and protein binding. We have exploited this sensitivity for the development of reliable electrochemical assays based on DNA charge transport at self-assembled DNA monolayers. Here, we discuss the characteristic features, applications, and advantages of DNA-mediated electrochemistry

The Bottom Line in Greenhouse Tomato Production

Crop Production/Industries,

Evaluation of directional vacuum-assisted breast biopsy: Report for the National Breast Cancer Centre final report, CHERE Project Report No 21

This project was commissioned by the National Breast Cancer Centre (NBCC). The objectives of the project, as set out in the call for expressions of interest, were to determine: 1. The costs associated with the introduction and use of directional vacuum-assisted breast biopsy(DVA breast biopsy) in Australia; and 2. Whether directional vacuum-assisted breast biopsy used for diagnostic purposes is cost-effectivein Australia when compared to core biopsy. The motivation for commissioning the project was an assessment of directional vacuum-assisted breast biopsy conducted by the Medical Services Advisory Committee (MSAC) which concluded that the procedure is safe and more effective than core biopsy. Although a cost-effectiveness analysis was not conducted as part of the MSAC study, MSAC recommended that the costs associated with the procedure be investigated and that, pending a review of costs, the procedure receive interim Medicare funding at a higher level than was previously available. For the project reported here, data was required to be collected from both public and private sectors on the cost of introducing and using DVA breast biopsy and a cost-effectiveness analysis (CEA) conducted on the introduction and use of DVA breast biopsy with and without a prone table. The research question for the CEA was What is the impact on costs and number of open biopsies performed of using DVA breast biopsy compared to core biopsy for micro-calcification lesions? It is important to note that this question specifies both the outcome the CEA (change in the number of core biopsies performed) and that the investigation was to be confined to micro-calcification lesions only. An expert multidisciplinary working group was assembled to oversee the project. Following collection of data an interim report was produced for the working group. As DVABB is a relatively new technology in Australia the interim report indicated that the current number of sites performing DVABB and the level of experience of users was insufficient to provide meaningful data to achieve the project aims. On the advice of the working group it was agreed to suspend the project at this juncture. The NBCC will consider repeating the survey in the future.Breast cancer, diagnostics, breast biopsy, Australia

Perimeter Security and Intruder Detection Using Gravity Gradiometry: A Feasibility Study

Changes in the mass distribution around some point on the Earth’s surface induce corresponding changes to the magnitude and direction of the gravity vector at that location. The nine-tensor derivative of the gravity vector, or gravity gradient, is sensitive to very small changes in the gravity vector. With some assumptions, continuous measurement of the gravity gradient using a gravity gradiometer (GGI) is used to determine the location of a mass change in the local area near the instrument. This investigation sought to determine the effectiveness, operating characteristics, and limitations of a physical perimeter security system that uses an array of GGIs to detect and locate a human intruder. Results are obtained via computer simulations utilizing the closed form solution for calculating a gravity gradient given an object’s size and mass, as well as industry-predicted future GGI performance characteristics

Self-organized transition to coherent activity in disordered media

Synchronized oscillations are of critical functional importance in many biological systems. We show that such oscillations can arise without centralized coordination in a disordered system of electrically coupled excitable and passive cells. Increasing the coupling strength results in waves that lead to coherent periodic activity, exhibiting cluster, local and global synchronization under different conditions. Our results may explain the self-organized transition in a pregnant uterus from transient, localized activity initially to system-wide coherent excitations just before delivery.Comment: 5 pages, 4 figure