Role of adhesion between asperities in the formation of elastic solid/solid contacts.

We investigated the formation of a contact between a smooth sphere of elastomer and a micro-patterned elastomer substrate. We focussed our attention on the transition between a contact only established at the top of the pillars, and a mixed contact with a central zone of full contact surrounded by a top contact corona, which was observed when the normal load was increased. The full contact zone always nucleated with a finite radius, and the transition appears to be a first-order transition, with a hysteresis due to the creation of an adhesive zone between the pillars. We propose to include the effect of the new inter-pillar adhesion to produce a realistic treatment of the mechanics of these complex contacts. This new approach quantitatively accounts for the evolution of the observed jump in the radius of the full contact with the geometrical parameters of the pattern.

A case of sensitization to alitretinoin.

Alitretinoin is a unique retinoid authorised for the treatment of adults with severe chronic hand eczema (CHE) refractory to potent topical steroids. The most common adverse events (AEs) were typical class effects of oral retinoids including headache, flushing and skin disorders. To our knowledge, there are no cases of sensitization to alitretinoin reported in literature. We present a case of sensitization to alitretinoin.

Allergic diseases and climate changes: our experience and an update.

AIMS: Recent research has shown that there are many effects of climate change on aeroallergens and thus allergic diseases in humans. It is not easy to evaluate the impact of climate change and air pollution on the prevalence of allergic diseases. The present study is devoted to decipher the possible relationships between climatic changes and allergic diseases, and in particular with atopic dermatitis (AD). MATERIALS AND METHODS: To evaluate the aeroallergens effects on AD, we submitted to an allergological study protocol 59 children patients with AD to study the interaction between aeroallergens-atopy patch test (APT) and skin prick test (SPT). The same tests were performed on to the same patients after 24 months to assess the time trend. RESULTS: We found a high prevalence of house dust mites and grasses pollen APT positivity in AD's and in respiratory patients and we also found an increase in positive results in the same patients after 24 months. However, we observed a variation in the control group, in which in earlier tests all patients had negative results but after 24 months we found some positivity. CONCLUSION: We found a correlation between APT and SPT in AD and we observed a concordance between APT results and the atopy score index, underlying the triggering role of these aereoallergens in the atopic patient's skin reactivity.

Systemic contact dermatitis (SCD) due to dietary nickel.

Systemic contact dermatitis (SCD) can be caused by nickel in sensitized subjects. Nickel allergy is commonly characterized by localized reactions ensuring cutaneous exposure to this element. Systemic reactions can occur after dietary nickel ingestion. We report a case of a woman with Systemic Contact Dermatitis due to nickel.