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Xiao P.,London South Bank University | Xiao P.,Biox Systems Ltd. | Wong W.,Hong Kong Sanatorium and Hospital | Cottenden A.M.,University College London | Imhof R.E.,Biox Systems Ltd.
International Journal of Cosmetic Science | Year: 2012

Skin over-hydration is a common problem that affects many people who wear incontinence pads or diapers. The aim of this study is to develop a new method for stratum corneum (SC) over-hydration and SC water diffusion coefficient measurements using opto-thermal transient emission radiometry (OTTER) and evaporimetry. With OTTER, we can measure the SC surface hydration and hydration gradient. With evaporimetry, we can measure the time-dependent evaporative drying curves of water vapour flux density (WVFD). The combination of hydration results and WVFD results can yield information on the SC water diffusion coefficient and how it depends on the SC surface hydration level. The results show that SC water diffusion coefficient is non-linearly proportional to the SC surface hydration level. The results also show strong correlations between evaporative drying flux measured using the Evaporimeter and surface hydration estimated from OTTER measurements. © 2012 The Authors. ICS © 2012 Society of Cosmetic Scientists and the Société Française de Cosmétologie. Source


Cui Y.,London South Bank University | Xiao P.,London South Bank University | Xiao P.,Biox Systems Ltd. | Imhof R.E.,Biox Systems Ltd.
International Journal of Thermophysics | Year: 2013

Stratum corneum is the outermost skin layer, and the water content in stratum corneum plays a key role in skin cosmetic properties as well as skin barrier functions. However, tomeasure the water content, especially the water concentration depth profile, within stratum corneum is very difficult. Opto-thermal emission radiometry, or OTTER, is a promising technique that can be used for such measurements. In this paper, a study on stratum corneum hydration depth profiling by using a genetic algorithm (GA) is presented. The pros and cons of a GA compared against other inverse algorithms such as neural networks, maximum entropy, conjugate gradient, and singular value decomposition will be discussed first. Then, it will be shown how to use existing knowledge to optimize a GA for analyzing the opto-thermal signals. Finally, these latestGAresults on hydration depth profiling of stratum corneum under different conditions, as well as on the penetration profiles of externally applied solvents, will be shown. © Springer Science+Business Media New York 2013. Source


Xiao P.,London South Bank University | Xiao P.,Biox Systems Ltd. | Cui Y.,Sunrise Systems Ltd | Ciortea I.,Biox Systems Ltd. | And 3 more authors.
Journal of Physics: Conference Series | Year: 2010

We present our latest study on the thermal diffusivity effect in opto-thermal skin measurements. We discuss how thermal diffusivity affects the shape of opto-thermal signal, and how to measure thermal diffusivity in opto-thermal measurements of arbitrary sample surfaces. We also present a mathematical model for a thermally gradient material, and its corresponding opto-thermal signal. Finally, we show some of our latest experimental results of this thermal diffusivity effect study. © 2010 IOP Publishing Ltd. Source


Xiao P.,London South Bank University | Xiao P.,Biox Systems Ltd. | Ou X.,London South Bank University | Ciortea L.I.,Biox Systems Ltd. | And 2 more authors.
International Journal of Thermophysics | Year: 2012

This latest study on in vivo transdermal drug delivery by using opto-thermal radiometry and a capacitance-based fingerprint sensor is presented. A small amount of solvent was applied on the test sites of a volar forearm for a few minutes; opto-thermal measurements and fingerprint sensor measurements were performed both before the solvent application and periodically after. The results showed that, by selecting different detection wavelengths, opto-thermal radiometry could give the information either on the water concentration within skin or the solvent concentration within skin. The capacitance-based fingerprint sensor could clearly visualize solvent penetration through in vivo human skin, as it generated dynamic two-dimensional (2D) images of solvent distribution within skin, and combining with tape stripping, it was also possible to get solvent 3D depth profiles within skin. The correlation between opto-thermal transient emission radiometry and fingerprint sensor measurements was also evaluated. © 2012 Springer Science+Business Media New York. Source


Xiao P.,London South Bank University | Xiao P.,Biox Systems Ltd. | Ciortea I.L.,Biox Systems Ltd. | Singh H.,London South Bank University | And 4 more authors.
Journal of Physics: Conference Series | Year: 2010

We compared five different skin hydration measurement techniques, namely OTTER, Fingerprint sensors, Corneometer, Nova, and Moisture Checker, in order to understand the correlations between different skin hydration measurement techniques and to understand the repeatability of each technique. The measurements are performed on different in-vivo skin sites from different volunteers and at different hydration levels. The repeatability of different techniques is achieved by measuring the same skin site repeatedly. The correlations between different skin hydration measurement techniques are achieved by plotting results from different techniques against each other. The different skin hydration levels are achieved through the recovery period after a skin immersive hydration. © 2010 IOP Publishing Ltd. Source

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