Mathematical Modelling of Transient Thermography and Defect Sizing

The principle employed to obtain an image of a sub-surface defect by transient thermography is deceptively simple. A surface is heated by powerful flash lamps and subsequent thermal transients are recorded by an infrared camera. Defects cause perturbations in heat flow which are revealed by the camera. Whilst there is now a considerable body of practical experience of the application of the technique, there is rather less precise quantitative information about the image formation process that could lead to reliable defect sizing. In earlier papers [1,2] one of the authors considered circular air gap defects by treating them as buried uniformly heated disks. The thermal edge-effect occurring at the tip of a perfect crack-like defect was dealt with analytically by adapting the well established Wiener-Hopf [3] solution for the scattering of light or sound from the edge of a semi-infinite half-plane. The problem was solved in the frequency-domain, i.e. to obtain a thermal wave solution, and then a time-domain solution was obtained by a suitable transformation. The analysis showed an edge-effect amounting to a decay in temperature contrast over a distance of about a thermal diffusion length from the edge of the crack. A crucial feature of the edge-effect was the decay of thermal contrast to zero at the crack tip. This, and the edge-effect as a whole, is caused by the flow of heat around the crack tip from the hot upper surface of the crack to the cold under surface. The symmetry of this process ensures that there is no net flux increase for material in front of the crack tip

Mitochondrial haplotypes reveal low diversity and restricted connectivity in the critically endangered batoid population of a Marine Protected Area

ACKNOWLEDGEMENTS This study was supported by NatureScot, Scottish Government project SP02B, a Heredity Fieldwork Grant of the Genetics Society, and Save Our Seas Foundation project SOSF 470. We would like to thank Leigh Taylor, Ronnie Campbell and Roger Eaton for skippering the sampling charters in the Marine Protected Area and all anglers who provided skate recapture data. Thanks to Fenella Wood and Danielle Sloan for assisting on charter trips. Further, thanks go to Marine Scotland Science (Francis Neat), the Centre for Environment Fisheries and Aquaculture Science (Vicky Bendall and Stewart Hetherington), and the University of St Andrews for providing tissue samples and Lauren Smith and Dan Wise for contributing samples of egg cases.Peer reviewedPublisher PD

Regional differences in APD restitution can initiate wavebreak and re-entry in cardiac tissue: A computational study

Background Regional differences in action potential duration (APD) restitution in the heart favour arrhythmias, but the mechanism is not well understood. Methods We simulated a 150 × 150 mm 2D sheet of cardiac ventricular tissue using a simplified computational model. We investigated wavebreak and re-entry initiated by an S1S2S3 stimulus protocol in tissue sheets with two regions, each with different APD restitution. The two regions had a different APD at short diastolic interval (DI), but similar APD at long DI. Simulations were performed twice; once with both regions having steep (slope > 1), and once with both regions having flat (slope < 1) APD restitution. Results Wavebreak and re-entry were readily initiated using the S1S2S3 protocol in tissue sheets with two regions having different APD restitution properties. Initiation occurred irrespective of whether the APD restitution slopes were steep or flat. With steep APD restitution, the range of S2S3 intervals resulting in wavebreak increased from 1 ms with S1S2 of 250 ms, to 75 ms (S1S2 180 ms). With flat APD restitution, the range of S2S3 intervals resulting in wavebreak increased from 1 ms (S1S2 250 ms), to 21 ms (S1S2 340 ms) and then 11 ms (S1S2 400 ms). Conclusion Regional differences in APD restitution are an arrhythmogenic substrate that can be concealed at normal heart rates. A premature stimulus produces regional differences in repolarisation, and a further premature stimulus can then result in wavebreak and initiate re-entry. This mechanism for initiating re-entry is independent of the steepness of the APD restitution curve

ACVIM consensus statement on the diagnosis of immune-mediated hemolytic anemia in dogs and cats

Immune-mediated hemolytic anemia (IMHA) is an important cause of morbidity and mortality in dogs. IMHA also occurs in cats, although less commonly. IMHA is considered secondary when it can be attributed to an underlying disease, and as primary (idiopathic) if no cause is found. Eliminating diseases that cause IMHA may attenuate or stop immune-mediated erythrocyte destruction, and adverse consequences of long-term immunosuppressive treatment can be avoided. Infections, cancer, drugs, vaccines, and inflammatory processes may be underlying causes of IMHA. Evidence for these comorbidities has not been systematically evaluated, rendering evidence-based decisions difficult. We identified and extracted data from studies published in the veterinary literature and developed a novel tool for evaluation of evidence quality, using it to assess study design, diagnostic criteria for IMHA, comorbidities, and causality. Succinct evidence summary statements were written, along with screening recommendations. Statements were refined by conducting 3 iterations of Delphi review with panel and task force members. Commentary was solicited from several professional bodies to maximize clinical applicability before the recommendations were submitted. The resulting document is intended to provide clinical guidelines for diagnosis of, and underlying disease screening for, IMHA in dogs and cats. These should be implemented with consideration of animal, owner, and geographical factors

Rationale and design of the oral HEMe iron polypeptide Against Treatment with Oral Controlled Release Iron Tablets trial for the correction of anaemia in peritoneal dialysis patients (HEMATOCRIT trial)

Background: The main hypothesis of this study is that oral heme iron polypeptide (HIP; Proferrin (R) ES) administration will more effectively augment iron stores in erythropoietic stimulatory agent (ESA)-treated peritoneal dialysis (PD) patients than conventional oral iron supplementation (Ferrogradumet (R))

DBSolve Optimum: a software package for kinetic modeling which allows dynamic visualization of simulation results

<p>Abstract</p> <p>Background</p> <p>Systems biology research and applications require creation, validation, extensive usage of mathematical models and visualization of simulation results by end-users. Our goal is to develop novel method for visualization of simulation results and implement it in simulation software package equipped with the sophisticated mathematical and computational techniques for model development, verification and parameter fitting.</p> <p>Results</p> <p>We present mathematical simulation workbench DBSolve Optimum which is significantly improved and extended successor of well known simulation software DBSolve5. Concept of "dynamic visualization" of simulation results has been developed and implemented in DBSolve Optimum. In framework of the concept graphical objects representing metabolite concentrations and reactions change their volume and shape in accordance to simulation results. This technique is applied to visualize both kinetic response of the model and dependence of its steady state on parameter. The use of the dynamic visualization is illustrated with kinetic model of the Krebs cycle.</p> <p>Conclusion</p> <p>DBSolve Optimum is a user friendly simulation software package that enables to simplify the construction, verification, analysis and visualization of kinetic models. Dynamic visualization tool implemented in the software allows user to animate simulation results and, thereby, present them in more comprehensible mode. DBSolve Optimum and built-in dynamic visualization module is free for both academic and commercial use. It can be downloaded directly from <url>http://www.insysbio.ru</url>.</p