The Experts below are selected from a list of 33 Experts worldwide ranked by ideXlab platform
Fabrice Pirot - One of the best experts on this subject based on the ideXlab platform.
-
Effects of physical and chemical treatments upon biophysical properties and micro-relief of human skin
Archives of Dermatological Research, 2008Co-Authors: Nicolas Atrux-tallau, Ngoc T. T. Huynh, Laurie Gardette, Cyril Pailler-mattéi, Hassan Zahouani, Eric Viviant, Henri Hirsch, Haftek Marek, Françoise Falson, Fabrice PirotAbstract:The aim of the present study was to determine the attendant effects of physical (tape-stripping) and chemical (three commercial hydrating formulations) treatments upon biophysical and micro-relief properties of human skin. In the first set of experiment, the effects of tape-stripping onto human stratum corneum (SC) biophysical and micro-relief properties were assessed in nine volunteers. Transepidermal water loss (TEWL), skin hydration and micro-relief Parameters (including total length of the lines in mm per mm^2; total surface in %; roughness of the skin measured in gray level (Ra); maximum profile valley (Rv) depth; maximum profile peak height (Rp); maximum height (Rt), peak density (Pc) and coefficient of anisotropy) were determined by using SkinEvidence^® Pro after subsequent tape-stripping of SC. The relevance of roughness determination as gray level by SkinEvidence^® Pro was confirmed by using surface roughness standards. In the second set of experiment, the effectiveness of three commercial hydrating formulations onto human SC biophysical Parameters and micro-relief properties were assessed in six volunteers. TEWL, hydration and micro-relief Parameters were assessed onto pre-treated acetone skin and then treated by three commercial hydrating formulations after 2, 4 and 6 h skin exposure. A linear relation between hydration and Cutaneous Parameters (total length of the lines, Ra and Rp) as function of SC removed was shown. Skin barrier properties evaluated by TEWL measurements, were not modified by topical formulations. However, skin treated by topical formulations showed slightly higher hydration than the one determined in control group, while micro-relief Parameters were not modified. In this study was showed that biophysical and micro-relief Parameters were closely related in tape-stripping experiment. Efficiency of topical formulations was suggested upon skin hydration but not onto skin micro-relief and barrier function recovering. From both experiments, it appears that different mechanisms relating to skin hydration and potential modification of Cutaneous micro-relief were suggested.
J C Barbenel - One of the best experts on this subject based on the ideXlab platform.
-
The influence of model parameter values on the prediction of skin surface temperature: II. Contact problems
Physics in medicine and biology, 1991Co-Authors: Zhanfeng Cui, J C BarbenelAbstract:For pt.I see ibid., vol.35, p.1683-97 (1990). A model of heat transfer and temperature distribution in the skin and superficial tissues which is based on a finite difference numerical solution of the one-dimensional multilayer coupled bioheat equation is presented. The model is used to investigate the influence of the values chosen to represent the physiological and thermal properties of the tissues on the skin surface temperature after contact with an external medium. It was found that the skin blood flow and dermal conductivity were the main Cutaneous Parameters which influence the contact response, but in terms of normalized temperature the response was little influenced by Cutaneous metabolic heat generation and deep dermal temperature. For contact with a good conductor, the transient behaviour was sensitive to the heat transfer coefficient on the outer surface and the thickness of the contact material, but insensitive to the conductivity of the material.
Nicolas Atrux-tallau - One of the best experts on this subject based on the ideXlab platform.
-
Effects of physical and chemical treatments upon biophysical properties and micro-relief of human skin
Archives of Dermatological Research, 2008Co-Authors: Nicolas Atrux-tallau, Ngoc T. T. Huynh, Laurie Gardette, Cyril Pailler-mattéi, Hassan Zahouani, Eric Viviant, Henri Hirsch, Haftek Marek, Françoise Falson, Fabrice PirotAbstract:The aim of the present study was to determine the attendant effects of physical (tape-stripping) and chemical (three commercial hydrating formulations) treatments upon biophysical and micro-relief properties of human skin. In the first set of experiment, the effects of tape-stripping onto human stratum corneum (SC) biophysical and micro-relief properties were assessed in nine volunteers. Transepidermal water loss (TEWL), skin hydration and micro-relief Parameters (including total length of the lines in mm per mm^2; total surface in %; roughness of the skin measured in gray level (Ra); maximum profile valley (Rv) depth; maximum profile peak height (Rp); maximum height (Rt), peak density (Pc) and coefficient of anisotropy) were determined by using SkinEvidence^® Pro after subsequent tape-stripping of SC. The relevance of roughness determination as gray level by SkinEvidence^® Pro was confirmed by using surface roughness standards. In the second set of experiment, the effectiveness of three commercial hydrating formulations onto human SC biophysical Parameters and micro-relief properties were assessed in six volunteers. TEWL, hydration and micro-relief Parameters were assessed onto pre-treated acetone skin and then treated by three commercial hydrating formulations after 2, 4 and 6 h skin exposure. A linear relation between hydration and Cutaneous Parameters (total length of the lines, Ra and Rp) as function of SC removed was shown. Skin barrier properties evaluated by TEWL measurements, were not modified by topical formulations. However, skin treated by topical formulations showed slightly higher hydration than the one determined in control group, while micro-relief Parameters were not modified. In this study was showed that biophysical and micro-relief Parameters were closely related in tape-stripping experiment. Efficiency of topical formulations was suggested upon skin hydration but not onto skin micro-relief and barrier function recovering. From both experiments, it appears that different mechanisms relating to skin hydration and potential modification of Cutaneous micro-relief were suggested.
Kalpana Bhargava - One of the best experts on this subject based on the ideXlab platform.
-
Nanozyme and Antioxidant Mimetic Cerium Oxide Nanoparticles Confer Excellent Protection against UV Induced Oxidative Damage in Skin
Free Radical Biology and Medicine, 2016Co-Authors: Aditya Arya, Anamika Gangwar, Mainak Das, Kalpana BhargavaAbstract:Generation of reactive oxygen species (ROS) is well accepted phenomenon in the skin exposed to Ultraviolet radiations. Ultraviolet radiations initiate an acute cascade of photochemical reactions culminating in the generation of reactive oxygen species such as superoxides. The downstream effects of these acute changes are directly involved in various Cutaneous changes such as sunburn erythema, phytocarcionoma and photoaging. The risk and exposure of UV radiations varies dramatically over time, space and topology across the globe suggesting the clinical relevance of identifying efficient UV protective agents. Based on the prior understanding from our lab and other studies cerium oxide has emerged as one of the promising antioxidants due to its superoxide dismutase and catalase mimetic activity. In this study we evaluated the UV protective efficiency of custom synthesized cerium oxide nanoparticles tagged with polyethyleneglycol (PEG-CNPs). The internalization of nanoparticles was successfully evaluated using DiD florescent tags. Preliminary studies were conducted on primary keratinocyte culture (HAEK cell line) using standard flow cytometry and microscopy. Significant reduction in ROS was observed in UV irradiated cells pretreated with 25 μM PEG-CNPs for 6 hours with concomitant reduction in protein modification such as carbonylation and nitrosylation and eventually the cell death. Moreover, on gaining confidence in cell culture model the hypothesis was tested in rat skin exposed to known doses of UV the PEG-CNPs showed significant reduction in clinical Cutaneous Parameters such as erythema. Histopatholical examination and basic biochemical indicators of oxidative stress including 8-OHdG, protein carbonyl, nitrosylation was significantly reduced on topical application prior to UV exposure. Apart from evaluating the minimum effective dose we also evaluated basic toxicological assessment and developed a topical formulation with hydrophobic solvents. In conclusion, the PEG-CNPs were highly efficient in protein skin from UV damage therefore providing a promising cosmaceutical application of this novel class of antioxidants.
Zhanfeng Cui - One of the best experts on this subject based on the ideXlab platform.
-
The influence of model parameter values on the prediction of skin surface temperature: II. Contact problems
Physics in medicine and biology, 1991Co-Authors: Zhanfeng Cui, J C BarbenelAbstract:For pt.I see ibid., vol.35, p.1683-97 (1990). A model of heat transfer and temperature distribution in the skin and superficial tissues which is based on a finite difference numerical solution of the one-dimensional multilayer coupled bioheat equation is presented. The model is used to investigate the influence of the values chosen to represent the physiological and thermal properties of the tissues on the skin surface temperature after contact with an external medium. It was found that the skin blood flow and dermal conductivity were the main Cutaneous Parameters which influence the contact response, but in terms of normalized temperature the response was little influenced by Cutaneous metabolic heat generation and deep dermal temperature. For contact with a good conductor, the transient behaviour was sensitive to the heat transfer coefficient on the outer surface and the thickness of the contact material, but insensitive to the conductivity of the material.
