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Auteur Reinhold H. Dauskardt |
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Application of substrate curvature method to differentiate drying stresses in topical coatings and human stratum corneum / K. Levi in INTERNATIONAL JOURNAL OF COSMETIC SCIENCE, Vol. 32, N° 4 (08/2010)
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Titre : Application of substrate curvature method to differentiate drying stresses in topical coatings and human stratum corneum Type de document : texte imprimé Auteurs : K. Levi, Auteur ; Reinhold H. Dauskardt, Auteur Année de publication : 2010 Article en page(s) : p. 294-298 Note générale : Bibliogr. Langues : Anglais (eng) Catégories : Peau -- Histopathologie
Peau -- MaladiesTags : 'Stratum corneum' 'Mécanique des couches minces' 'Peau sèche' 'Revêtements topiques' Index. décimale : 668.5 Parfums et cosmétiques Résumé : Malgré l’utilisation extensive des enduits topiques dans les produits cosmétiques, leur effet sur les propriétés mécaniques de la peau humaine et la perception de l’étanchéité de la peau à cause des stress de dessèchement n’est pas très bien compris. Nous décrivons l’application d’une technique de courbure de substrat récemment développé pour caractériser les stress dans les enduits topiques qui sèchent. Nous utilisons ensuite cette méthode pour mesurer les effets combinés de l’enduit appliqué à la couche cornée (SC) ou les stress de dessèchement totaux pourraient avoir des contributions provenant de l’enduit, de la SC et des interactions entre l’enduit et la SC. Nous montrons comment séparer les différentes contributions de l’enduit et de la SC. DOI : 10.1111/j.1468-2494.2010.00568.x En ligne : http://onlinelibrary.wiley.com/doi/10.1111/j.1468-2494.2010.00568.x Format de la ressource électronique : Permalink : https://e-campus.itech.fr/pmb/opac_css/index.php?lvl=notice_display&id=9864
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Code-barres Cote Support Localisation Section Disponibilité 012418 - Périodique Bibliothèque principale Documentaires Disponible Drying stress and damage processes in human stratum corneum / K. Levi in INTERNATIONAL JOURNAL OF COSMETIC SCIENCE, Vol. 32, N° 4 (08/2010)
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Titre : Drying stress and damage processes in human stratum corneum Type de document : texte imprimé Auteurs : K. Levi, Auteur ; R. J. Weber, Auteur ; J. Q. Do, Auteur ; Reinhold H. Dauskardt, Auteur Année de publication : 2010 Article en page(s) : p. 276-293 Note générale : Bibliogr. Langues : Anglais (eng) Catégories : Peau -- Histopathologie
Peau -- MaladiesTags : 'Stratum corneum' 'Mécanique des couches minces' 'Peau sèche' 'Dommages cutanés' Index. décimale : 668.5 Parfums et cosmétiques Résumé : Les états de la sécheresse de la couche cornée (SC) sont essentiels vis-à -vis des caractéristiques mécaniques et biophysiques et de son apparence. Ils jouent un rôle central dans les processus de la peau sèche. Cependant, les méthodes quantitatives qui caractérisent ces états font défaut et il existe peu d’explication quant aux effets de l’environnement asséchant, les expositions chimiques et les traitements hydratants. Nous décrivons l’application d’une technique de courbure du substrat adaptée aux tissus biologiques pour caractériser précisément le desséchement du SC séchage en fonction du temps après une gamme de séchage environnementaux et chimiques. Le SC a été observé avec des niveaux de stress pouvant aller jusqu’à ∼ 3 MPa sur une période de 8 heures, avec un pré-traitement et le séchage ambiant. Une relation entre la sécheresse du SC et l’eau de l’environnement a étéétablie. L’effet du glycérol sur la réduction de la sècheresse et celui des tensioactifs irritants sur le SC ont été quantifiés. L’extensions de la méthode lors d’une surveillance en continu de la CS souligne les réponses lors du changement du contenu en humidité ambiante et en température. Enfin, une analyse biomécanique rend compte de la déshydratation du SC comme force motrice mécanique des dommages de la peau sèche. DOI : 10.1111/j.1468-2494.2009.00557.x En ligne : http://onlinelibrary.wiley.com/doi/10.1111/j.1468-2494.2009.00557.x Format de la ressource électronique : Permalink : https://e-campus.itech.fr/pmb/opac_css/index.php?lvl=notice_display&id=9863
in INTERNATIONAL JOURNAL OF COSMETIC SCIENCE > Vol. 32, N° 4 (08/2010) . - p. 276-293[article]Réservation
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Code-barres Cote Support Localisation Section Disponibilité 012418 - Périodique Bibliothèque principale Documentaires Disponible Effect of emulsifiers on drying stress and intercellular cohesion in human stratum corneum / F. Ansari in INTERNATIONAL JOURNAL OF COSMETIC SCIENCE, Vol. 42, N° 6 (12/2020)
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Titre : Effect of emulsifiers on drying stress and intercellular cohesion in human stratum corneum Type de document : document électronique Auteurs : F. Ansari, Auteur ; C. McGuiness, Auteur ; B. Zhang, Auteur ; Reinhold H. Dauskardt, Auteur Année de publication : 2020 Article en page(s) : p. 581-589 Note générale : Bibliogr. Langues : Anglais (eng) Catégories : Cohésion intercelullaire
Cosmétiques -- Analyse
Couche cornée
Emulsifiants
Formulation (Génie chimique)
Peau -- Soins et hygiène
Produits hydratants
SéchageIndex. décimale : 668.5 Parfums et cosmétiques Résumé : - Objectives : Emulsifier molecules, with their amphiphilic character, are ubiquitous in moisturizing creams and primarily serve to disperse the water-insoluble molecules such as emollients, oils, lipids and fats in water. The objective of this study was to investigate the effect of emulsifier molecules on the barrier and biomechanical properties of human stratum corneum (SC) and to compare the efficacy of emulsifier molecules when used in a fully formulated moisturizing cream.
- Methods : We employed methods based on thin-film mechanics to measure the drying stress and intercellular cohesion in the SC. The emulsifier molecules or moisturizing creams formulated with them were applied to a fully hydrated SC adhered to a glass substrate. In-plane stress developed in the SC during drying was then measured by tracking changes in the curvature of the glass substrate. The intercellular cohesion within the SC was measured by means of a double cantilever beam (DCB) set-up, where the treated or untreated SC was sandwiched between two substrates, and the delamination energy calculated by measuring the force required to drive a crack through the SC. Moisturizing cream diffusivity through the stratum corneum was measured by spectroscopic technique and related to internal SC stress and fracture energy.
- Results : We observe significant differences in the biomechanical behaviour of SC when moisturizing creams with different emulsifier molecules are applied on isolated stratum corneum ex vivo. The reduction in maximum stress varied between 12% and 26% depending on the emulsifier molecules used in the formulation. The intercellular cohesion and the diffusion of molecules in the formulated moisturizing creams through the SC were also found to be strongly dependent on the type of emulsifier molecule used in the formulation.
- Conclusions : The biomechanical and barrier properties of the human stratum corneum show strong dependence on the emulsifier molecule used in the moisturizing creams, even when the creams included only ~3 weight% emulsifier molecules. Moreover, we found that the reduction in SC peak stress was strongly correlated with the formulation diffusivity into the SC. The moisturizing creams diffusing fastest into the SC had the largest reduction in peak stress and vice versa.Note de contenu : - MATERIALS AND METHODS : Formulated moisturizing creams - Tissue preparation - Drying stress measurement - SC cohésion - Diffusivity measurement
- RESULTS AND DISCUSSION : Drying stress - Diffusion - SC cohesion
- Table 1 : Important parameters of the moisturizing creams investigated in this study
- Table 2 : Relevant physical properties of the emulsifier and emollient molecules used in this studyDOI : https://doi.org/10.1111/ics.12643 En ligne : https://drive.google.com/file/d/1B7LGHeaNR4IpitcqVdB81A-RufWdxkVs/view?usp=shari [...] Format de la ressource électronique : Permalink : https://e-campus.itech.fr/pmb/opac_css/index.php?lvl=notice_display&id=35424
in INTERNATIONAL JOURNAL OF COSMETIC SCIENCE > Vol. 42, N° 6 (12/2020) . - p. 581-589[article]Exemplaires
Code-barres Cote Support Localisation Section Disponibilité aucun exemplaire Emollient structure and chemical functionality effects on the biomechanical function of human stratum corneum / C. Berkey in INTERNATIONAL JOURNAL OF COSMETIC SCIENCE, Vol. 42, N° 6 (12/2020)
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Titre : Emollient structure and chemical functionality effects on the biomechanical function of human stratum corneum Type de document : document électronique Auteurs : C. Berkey, Auteur ; D. Kanno, Auteur ; Annette Mehling, Auteur ; J.-P. Koch, Auteur ; W. Eisfeld, Auteur ; M. Dierker, Auteur ; M. Bhattacharya, Auteur ; Reinhold H. Dauskardt, Auteur Année de publication : 2020 Article en page(s) : p. 605-614 Note générale : Bibliogr. Langues : Anglais (eng) Catégories : Biomécanique
Caractérisation
Cosmétiques
Couche cornée
Dermo-cosmétologie
Emollients
Fourier, Spectroscopie infrarouge à transformée de
Peau -- analyse
Peau -- Soins et hygiène
Pénétration (physique)Index. décimale : 668.5 Parfums et cosmétiques Résumé : - Objective : Cosmetic emollients are widely used in skincare formulations due to their ability to 'soften' the skin and modulate formulation spreadability. Though emollients are commonly used, little is known about their effects on the biomechanical barrier properties of human stratum corneum (SC), which play a critical role in consumer perception of formulation efficacy. Accordingly, our objective was to provide new insights with a study involving fourteen cosmetic emollient molecules with widely varying structures, molecular weights, SC diffusivities, topological polar surface areas (TPSAs), viscosities and chemical functionalities.
- Methods : Mechanical stress in the SC was measured in vitro using a substrate curvature measurement technique. Stress development due to SC drying was measured before and after topical treatment with cosmetic emollients. Emollient diffusivity and alterations to lipid content in SC after treatment were measured via ATR-FTIR spectroscopy. The maximum penetration volume of emollient in SC was characterized to elucidate mechanisms underlying emollient effects on stress.
- Results : The application of all cosmetic emollients caused a reduction in SC mechanical stress under dehydrating conditions, and a linear correlation was discovered between emollient penetration volume and the degree of stress reduction. These molecules also induced increases in stress equilibration rate, signalling changes to SC transport kinetics. Stress equilibration rate increases linearly correlated with decreasing intensity of the νCH2 band, indicating a previously unknown interaction between cosmetic emollients and SC lipids. Stress and penetration volume results were rationalized in terms of a multi-parameter model including emollient molecular weight, diffusivity, TPSA and viscosity.
- Conclusion : We provide a new rational basis for understanding the effects of cosmetic emollient choice on biomechanical properties affecting SC barrier function and consumer perception. We demonstrate for the first time that emollients very likely reduce SC mechanical stress through their ability to take up volume when penetrating the SC, and how molecular weight, SC diffusivity, TPSA and viscosity are predictive of this ability. As cosmetic formulations continue to evolve to meet the needs of customers, emollient molecules can be selected that not only contribute to formulation texture and/or spreadability but that also leverage this novel connection between emollient penetration and SC biomechanics.Note de contenu : - Stratum corneum preparation
- Emollient treatments
- Drying stress substrate curvature
- Penetration volume measurements
- ATR-FTIR spectroscopy
- Table 1 : Names and relevant physical properties of emollients
- Table 2 : Drying stress, penetration volume and diffusivity measurements of SC treated with emollientsDOI : https://doi.org/10.1111/ics.12656 En ligne : https://drive.google.com/file/d/1iqy3w2otbjm-FJAy68hPKAWIkLGWpBIb/view?usp=shari [...] Format de la ressource électronique : Permalink : https://e-campus.itech.fr/pmb/opac_css/index.php?lvl=notice_display&id=35427
in INTERNATIONAL JOURNAL OF COSMETIC SCIENCE > Vol. 42, N° 6 (12/2020) . - p. 605-614[article]Exemplaires
Code-barres Cote Support Localisation Section Disponibilité aucun exemplaire From decoding the perception of tightness to a clinical proof of soothing effects derived from natural ingredients in a moisturizer / Sebastian Hendrickx-Rodriguez in INTERNATIONAL JOURNAL OF COSMETIC SCIENCE, Vol. 44, N° 5 (10/2022)
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Titre : From decoding the perception of tightness to a clinical proof of soothing effects derived from natural ingredients in a moisturizer Type de document : document électronique Auteurs : Sebastian Hendrickx-Rodriguez, Auteur ; Sophie Connetable, Auteur ; Barbara Lynch, Auteur ; Joseph Pace, Auteur ; Ross Bennett-Kennett, Auteur ; Gustavo S. Luengo, Auteur ; Reinhold H. Dauskardt, Auteur ; Anne Potter, Auteur Année de publication : 2022 Article en page(s) : p. 486-499 Note générale : Bibliogr. Langues : Anglais (eng) Catégories : Barrière cutanée
Cosmétiques
Couche cornée
Dermo-cosmétologie
Etanchéité
Formulation (Génie chimique)
Modèles numériques
Peau -- Physiologie
Peau -- Soins et hygiène
Produits hydratantsIndex. décimale : 668.5 Parfums et cosmétiques Résumé : - Objective : To decode the feeling of skin tightness after application of a cosmetic product and how to soothe this discomfort. To pursue this aim, we considered the ingredient's effect on stratum corneum (SC) biomechanics to differentiate between consumers prone to tightness from those that are not and correlate these effects with mechanoreceptor activation.
- Methods : In vivo clinical trials were used to assess the tightness perception dichotomy between groups of Caucasian women; in vitro experiments were used to measure the mechanical stresses induced in the SC after cleanser and moisturizer application; and in silico simulations were used to illustrate how the measured mechanical stresses in the SC result in the development of strains at the depth of cutaneous mechanoreceptors, triggering tightness perceptual responses.
- Results : Before any cream application, women prone to tightness tend to have a more rigid SC than their less sensitive counterparts, however cleanser application increases SC stiffness in all women. Surprisingly, no correlation was found between tightness perception and hydration measurements by the Corneometer or barrier function, as evaluated by transepidermal water loss. Self-declared tightness and dryness scores were strongly associated with a self-described sensitive skin. After application of the optimized moisturizing formula, Osmoskin® containing natural waxes with good filming properties, consumers report a strong decrease in tightness and dryness perception. These results match with laboratory experiments where the cleanser was shown to increase SC drying stresses by 34%, while subsequent application of Osmoskin® decreased stresses by 48%. Finite element modelling, using experimental results as input, elucidates the differences in perception between the two groups of women. It makes clear that Osmoskin® changes the mechanical status of the SC, producing strains in underlying epidermis that activates multiple cutaneous mechano-receptors at a level correlated with the self-perceived comfort.
- Conclusion : Integration of the in vivo, in vitro and in silico approaches provides a novel framework for fully understanding how skin tightness sensations form and propagate, and how these sensations can be alleviated through the design of an optimized moisturizer.Note de contenu : - MATERIALS AND METHODS : In vivo clinical study design - In vitro mechanical stress - In silico computational modelling of cosmetic treatment effects - Ingredients and formulation
- RESULTS : Tightness decoding: In vivo instrumental, sensorial and clinical results - Impact of an optimized moisturizer to reduce tightness after a harsh cleanser treatment: In vivo instrumental, sensorial and clinical results - In vitro results: Drying stress profile of the stratum corneum - Modelling results: Impact of cleanser and Osmoskin® moisturizer on mechanoreceptors’ activationDOI : https://doi.org/10.1111/ics.12797 En ligne : https://drive.google.com/file/d/1uie85R4gYHbZxj0Rs4cnzo7qit_aP8I5/view?usp=shari [...] Format de la ressource électronique : Permalink : https://e-campus.itech.fr/pmb/opac_css/index.php?lvl=notice_display&id=38148
in INTERNATIONAL JOURNAL OF COSMETIC SCIENCE > Vol. 44, N° 5 (10/2022) . - p. 486-499[article]Exemplaires
Code-barres Cote Support Localisation Section Disponibilité aucun exemplaire Screening sunscreens : protecting the biomechanical barrier function of skin from solar ultraviolet radiation damage / C. Berkey in INTERNATIONAL JOURNAL OF COSMETIC SCIENCE, Vol. 39, N° 3 (06/2017)
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