BackgroundBuruli ulcer (BU) is an infection of the subcutaneous tissue leading to chronic necrotizing skin ulcers. The causative pathogen, Mycobacterium ulcerans, grows best at 30°C–33°C and not above 37°C. We explored the safety, tolerability and efficacy of phase change material (PCM), a novel heat application system for thermotherapy of BU.Methodology/Principal FindingsIn a prospective observational single centre proof-of-principle trial in Ayos/Cameroon, six laboratory reconfirmed patients with ulcerative Buruli lesions received 28–31 (ulcers ≤2 cm) or 50–55 (ulcers >2 cm) days of thermotherapy with the PCM sodium acetate trihydrate as heat application system. This PCM is widely used in commercial pocket heat pads, it is easy to apply, rechargeable in hot water, non-toxic and non-hazardous to the environment. All patients enrolled in the trial completed treatment. Being completely mobile during the well-tolerated heat application, acceptability of the PCM bandages was very high. In patients with smaller ulcers, wounds healed completely without further intervention. Patients with large defects had skin grafting after successful heat treatment. Heat treatment was not associated with marked increases in local inflammation or the development of ectopic lymphoid tissue. One and a half years after completion of treatment, all patients are relapse-free.Conclusions/SignificanceOur reusable PCM-based heat application device appears perfectly suited to treat BU in endemic countries with limited resources and infrastructure.Trial RegistrationControlled-Trials.com ISRCTN88392614

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A mathematical model was developed and validated to predict the thermal behaviour of a heat application device based on a phase change material (pcm) for the heat treatment of Mycobacterium ulcerans infection (Buruli ulcer). The thermal model allows the prediction of skin surface temperatures and an optimization of the amount of pcm with respect to discharge time. A first prototype of such a pcm bandage was manufactured and used in a proof-of-principal trial in Cameroon. The experimental data were analysed and yielded no difference in thermoregulatory response between people living in hot or moderate climate. Short-term maximum skin surface temperatures of 42 degrees C are tolerable; the pcm bandage keeps the skin surface temperature above 40 degrees C for about four to five hours. This makes such pcm bandages an ideal device for the heat treatment of Buruli ulcer. The pcm bandage is easy to apply, cheap, and thus is well suited for use in low-resource countries.

The authors present a dynamic simulation of the thermal behavior of a multilayer plane wall, integrated with Phase Change Materials (PCMs), exposed to solar radiation in summer conditions, in a Mediterranean site. PCMs are a promising kind of heat storage materials that are particularly good in some climatic conditions: if properly placed, they can decrease heat flux through the walls, thus reducing cooling loads in buildings. Due to their strong non-linearity in thermal behavior, PCMs must be carefully modeled, possibly in transient conditions. The dynamic model consists of two main distinct parts. First, a solar radiation model is implemented, based on the daily evolution of the solar angles. This solution uses the results of a novel simple model for splitting the diffuse and the direct solar radiation starting from data on total radiation on a horizontal surface only. Then, solar radiation is used as a boundary condition for the dynamic modeling of a typical multilayer lightweight wall provided with one insulation layer integrated by PCMs. The calculated of solar effect and cooling loads are studied for three different melting temperatures of the PCMs.

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