39 research outputs found

    From sun to earth.

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    peer reviewedSun emits a vast array of electromagnetic radiations. After a long but fast journey, the spectrum of visible and ultraviolet light, and infrared radiations reaches the furthermost boundaries of the Earth. Only a fraction of them reaches the biosphere. Photogeoclimatology primarily depends on this energy and is modulated by the latitude, soil relief, seasons and nycthemeral cycle

    Skin photophysics and colors.

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    peer reviewedThe optical properties of skin and of chromophores orientate and absorbe light. The resulting skin colour can be assessed by visual inspection or by objective methods. Spectrophotometry, tristimulus colorimetry and computerized image analysis are well codified methods. Epidermal melanisation is detected with great sensitivity under ultraviolet light illumination

    Comedolysis by a lipohydroxyacid formulation in acne-prone subjects.

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    Post-summertime exacerbation of acne is not a rare event. This study was conducted to assess the preventive effect of a proprietary formulation containing 2-hydroxy-5-octanoyl benzoic acid on this environmental related disease. This compound is commonly called beta-lipohydroxyacid (LHA). Among a randomized group of 14 acne-prone women, 12 who developed cornified follicular plugs the end of summertime were treated by the LHA formulation twice daily for 2 weeks. Ten of 14 other women who presented the same skin condition remained untreated as controls. The comedolytic effect was assessed using non-invasive ultraviolet-light video recording combined with computerized image analysis. The cornified follicular plugs were progressively cleared in 10/12 LHA-treated women and in 3/10 untreated volunteers. Analytical assessments showed a significant decrease in both the number and total size of microcomedones in the LHA-treated women. By contrast, no quantitative change was disclosed in the untreated group. It is concluded that the tested LHA formulation exerts comedolytic properties that might help in preventing post-summertime acne exacerbations

    Irritation cutanee et vitesse de propagation d'ondes ultrasonores.

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    Cutaneous irritation is a stereotyped response of the skin to any physical or chemical insult. Its main manifestations encompass inflammatory erythema and an alteration of the cutaneous microrelief showing increased roughness, dehydration and erratic desquamation. Several instrumental methods can indirectly assess the issues of cutaneous irritation on human stratum corneum. The aim of the present study was to measure the speed of propagation of ultrasound shear waves in the skin irritated by anionic surfactants. The study was performed in 25 healthy subjects of both sexes. Occlusive patches of a 10% solution of anionic surfactants were applied to a forearm of each volunteer. The other forearm served as an untreated control site. Patches remained in place for 24 h. Three hours later, another patch was placed again for 21 h. Resonance running time measurements (RRTM) of the ultrasound shear wave were performed using a Reviscometer((R)) RVM 600. Measurements were performed at entry in the study and 2 days after removing the second patch. Desquamative xerosis was obvious at the sites patched with the surfactant solution. RRTM values were significantly (P < 0.0001) lower than those at the control site. Hence, the speed of propagation of ultrasound shear waves was shown to be increased at an irritated site compared to an intact site. In conclusion, this study shows that the propagation speed of ultrasounds is influenced by the skin surface nature, being considerably increased in skin altered by surfactants

    L'agonie du taratata auprès du clinicien.

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    peer reviewedLe clinicien est à la croisée des chemins entre la rigueur scientifique et le taratata d’une certaine communication bien moins sérieuse. Dans ce contexte, la recherche de l’objectivité est primordiale dans les études cliniques. Nous résumons les aspects principaux des méthodes de dénombrement, de classement, de mesures paramétriques et d’évaluations sur échelles structurée ou non structurée
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