Modelling of edge profiles in pigmented skin lesions

The sharpness of the lesion boundary and the contrast between the lesion and the surrounding skin provide important diagnostic information in the assessment of pigmented skin lesions. This paper presents a new method for computing these parameters by employing an edge model based on a sigmoid function. For each radial profile of the lesion, optimal parameters are found by using an iterative least-squares method. The level and nature of variability of these parameters along the boundary will be correlated with lesion diagnosis in a future study. The method also returns the location equivalent to “zero-crossing” for each profile, thus producing a lesion outline. Additionally, the spread of the pigment beyond the zero-crossing point is computed, thus showing the lesion extent

Texture based characterization of sub-skin features by specified laser speckle effects at λ=650nm region

The file attached to this record is the author's final peer reviewed version. The Publisher's final version can be found by following the DOI link.Objective: The textural structure of “skin age” related sub-skin components enables us to identify and analyse their unique characteristics, thus making substantial progress towards establishing an accurate skin age model. Methods: This is achieved by a two stage process. First by the application of textural analysis using laser speckle imaging, which is sensitive to textural effects within the λ=650 nm spectral band region. In the second stage a Bayesian inference method is used to select attributes from which a predictive model is built. Results: This technique enables us to contrast different skin age models, such as the laser-speckle effect against the more widely used normal light (LED) imaging method, whereby it is shown that our laser speckle based technique yields better results. Conclusion: The method introduced here is non-invasive, low-cost and capable of operating in real-time; having the potential to compete against high-cost instrumentation such as confocal microscopy or similar imaging devices used for skin age identification purposes

Characterising pattern asymmetry in pigmented skin lesions

Abstract. In clinical diagnosis of pigmented skin lesions asymmetric pigmentation is often indicative of melanoma. This paper describes a method and measures for characterizing lesion symmetry. The estimate of mirror symmetry is computed first for a number of axes at different degrees of rotation with respect to the lesion centre. The statistics of these estimates are the used to assess the overall symmetry. The method is applied to three different lesion representations showing the overall pigmentation, the pigmentation pattern, and the pattern of dermal melanin. The best measure is a 100% sensitive and 96% specific indicator of melanoma on a test set of 33 lesions, with a separate training set consisting of 66 lesions

3D non-invasive inspection of the skin lesions by close-range and low-cost photogrammetric techniques

The main research group is CCI in collaboration with HLS (School of Pharmacy) Open Access articleIn dermatology, one of the most common causes of skin abnormality is an unusual change in skin lesion structure which may exhibit very subtle physical deformation of its 3D shape. However the geometrical sensitivity of current cost-effective inspection and measurement methods may not be sufficient to detect such small progressive changes in skin lesion structure at micro-scale. Our proposed method could provide a low-cost, non-invasive solution by a compact system solution to overcome these shortcomings by using close-range photogrammetric imaging techniques to build a 3D surface model for a continuous observation of subtle changes in skin lesions and other features.https://www.ias-iss.org/ojs/IAS/article/view/1730/105

Use of Bayesian Inference Method to Model Vehicular Air Pollution in Local Urban Areas

The file attached to this record is the author's final peer reviewed version.Traffic Related Air Pollution (TRAP) studies are usually investigated using different categories such as air pollution exposure for health impacts, urban transportation network design to mitigate pollution, environmental impacts of pollution, etc. All of these subfields often rely on a robust air pollution model, which also necessitates an accurate prediction of future pollutants. As is widely accepted by the heath authorities, TRAP is considered to be the major health issue in urban areas, and it is difficult to keep pollution at harmless levels if the time sequenced dynamic pollution and traffic parameters are not identified and modelled efficiently. In our work here, artificial intelligence techniques, such as Bayesian Networks with an optimized configuration, are used to deliver a probabilistic traffic data analysis and predictive modelling for air pollution (SO2, NO2 and CO) at very local scale of an urban region with up to 85% accuracy. The main challenge for traditional data analysis is a lack of capability to reveal the hidden links between distant data attributes (e.g. pollution sources, dynamic traffic parameters, etc.), whereas some subtle effects of these parameters or events may play an important role in pollution on a long-term basis. This study focuses on the optimisation of Bayesian Networks to unveil hidden links and to increase the prediction accuracy of TRAP considering its further association with a predictive GIS syste

An improvement of skin aging assessment by non-invasive laser speckle effect: A comparative texture analysis

Skin aging is a complex biological process that is yet to be successfully modelled as it depends on various internal and external factors. This work therefore investigates novel low-cost skin aging assessment technique and equipment by using robust analysis of textural features unified with a laser-speckle imaging method, which is found to be quite capable of detecting multi-layer cellular textural changes exhibited by the biological skin aging process. This study and low-cost product seem to be the first of its kind, which is expected to bring great benefit to both healthcare and cosmetic sectors

Effect of hole reinforcement on the buckling behaviour of thin-walled beams subjected to combined loading

In this study, the effect of hole reinforcement on the buckling behaviour of thin-walled structures mostly used in aircrafts is investigated under combined loads. A fuselage floor beam with real dimensions is used for the buckling analysis, and a parametric study based on several loading scenarios is considered. Investigated structures include different ratios of hole diameter to reinforcement width (d/w), ratios of reinforcement height to web plate thickness (h/t), and the aspect ratio of the web plate (a/b). The material of the thin walled structure is Al 7075 series. The commercial finite element analysis program, ABAQUS, is used for buckling analysis. The loading scenarios such as compression, shear, and bending, as well as combined loading are considered using a validated finite element model. For the selected range of geometrical parameters, buckling loads and allowable buckling stresses are computed. Furthermore, compression, shear and bending rates are calculated, and the interaction curves are plotted with the help of data obtained from the finite element studies. The effect of loading scenario on the buckling strength is compared for beam without a hole, with a hole and with a hole plus reinforcement cases. The main goal of this study is to provide engineers graphical data that can be used to check whether or not a structure will fail under several defined load cases including combined loading

Discoloration effects of traditional turkish beverages on different composite restoratives

PubMed: 28174359Aim: The aim of this study was to evaluate the discoloring effects of five beverages including, especially, traditional Turkish ones on five commonly used dental composites by using a spectrophotometer device. Materials and methods: Five methacrylate-based composites (shade A2) were selected to evaluate their color stability (175 disk samples). Four of them (Filtek Ultimate Universal, Clearfil Majesty ES-2, Tetric EvoCeram, and Cavex Quadrant Universal LC) were nanofilled universal composites for both anterior and posterior restorations, and one (Clearfil Majesty Posterior) was nano-superfilled for posterior restorations. The tested beverages were tamarind syrup, ottoman syrup, turnip juice, pomegranate juice, and distilled water (control). All samples were kept in an incubator at 37°C for 12 days (measured at 3rd, 6th, 12th day intervals) in immersion solutions which was equivalent to 1 year in vivo. Color measurements were made with VITA Easyshade Advance (Vident, Brea, CA) spectrophotometer device according to CIE L*a*b* system. Statistical analysis was performed with analysis of variance and least significant difference test to analyze differences in L*a*b* and ?E values. Results: All materials showed significant discoloration (p < 0.05) when compared with the control group. The highest ?E was observed in turnip juice, whereas ottoman syrup had the lowest ?E. Tetric EvoCeram showed the lowest ?E, while Clearfil Majesty ES-2 showed the highest ?E. Conclusion: In all the groups tested, clinically unacceptable ?E values were obtained. Although color stability of methacrylatebased composites has been widely investigated, this has not been done before with these kinds of immersion solutions. Clinical significance: Potential discoloration might be limited by dietary adjustments based on in vitro evaluations