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Skin lipid organization, composition and barrier function / Joke A. Bouwstra in IFSCC MAGAZINE, Vol. 10, N° 4 (10-11-12/2007)

[article]  inIFSCC MAGAZINE > Vol. 10, N° 4 (10-11-12/2007) . - p. 297-307 Titre : Skin lipid organization, composition and barrier function Type de document : texte imprimé Auteurs : Joke A. Bouwstra, Auteur ; Gert S. Gooris, Auteur ; Maria Ponec, Auteur Année de publication : 2008 Article en page(s) : p. 297-307 Note générale : Bibliogr. Langues : Anglais (eng) Tags : Céramides  FTIR  'Organisation  lipidique'  'Stratum  corneum'  'Diffraction  rayons  X' Index. décimale : 668.5 Parfums et cosmétiques Résumé : The primary function of the skin is to act as a barrier against unwanted influences from the environment and to protect the body from water loss. The barrier function of the skin is located in the superficial layer of the skin, the stratum corneum. The stratum corneum consists of dead cells filled with keratin and water, the corneocytes, embedded in lipid regions. As the lipid regions are the only continuous structure in the stratum corneum, they are considered to be very important for the skin barrier function. The main lipid classes are ceramides, cholesterol and free fatty acids. In this paper the lipid organization in human stratum corneum is reviewed. In addition, the role the various lipid classes play in lipid organization is discussed using mixtures prepared from either native human ceramides or synthetic ceramides. Finally, a model is described which allows study of the relation between lipid composition, organization and barrier function. This model is referred to as the stratum corneum substitute. Permalink : https://e-campus.itech.fr/pmb/opac_css/index.php?lvl=notice_display&id=10412 [article]

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A new decorin-like tetrapeptide for optimal organization of collagen fibers / Arturo Puig in IFSCC MAGAZINE, Vol. 10, N° 4 (10-11-12/2007)

[article]  inIFSCC MAGAZINE > Vol. 10, N° 4 (10-11-12/2007) . - p. 309-314 Titre : A new decorin-like tetrapeptide for optimal organization of collagen fibers Type de document : texte imprimé Auteurs : Arturo Puig, Auteur ; J. M. Garcia Anton, Auteur ; Montserrat Mangues, Auteur Année de publication : 2008 Article en page(s) : p. 309-314 Note générale : Bibliogr. Langues : Anglais (eng) Tags : Collagène  Décorine  Diamètre  Fibre  Organisation Index. décimale : 668.5 Parfums et cosmétiques Résumé : Decorin interacts with collagen via its protein core and influences collagen fibrillogenesis, thus regulating excessive bundle-like aggregation of collagen. As skin ages, there is a lack of functional decorin which results in disrupted collagen fibers and a reduction in the tensile strength of the skin. Therefore, a substitute for decorin would make up for the non-functional decorin that is present as we age. Two tetrapeptide sequences were identified as the specific binding sites of decorin to collagen fibrils. These sequences were engineered in order to generate new tetrapeptides with improved affinity that would present a decorin-like activity. A focused library of several candidates was synthesized containing only tetrapeptides that mimicked the binding sequences of decorin. The candidates were screened with an in vitro collagen fibrillogenesis assay, and the tetrapeptide with the INCI name Tripeptide-10 Citrulline achieved the best results. Like decorin, this synthetic tetrapeptide proved in in vitro tests to regulate collagen fibrillogenesis and influence the diameter of collagen fibers, making them thinner and more uniform. Tripeptide-10 citrulline is a new cosmetic active to specifically target collagen fiber organization. Skin collagen quality is addressed rather than skin collagen quantity. Tripeptide-10 citrulline ensures uniformity of fibril diameter and increases skin suppleness due to a better cohesion of collagen fibers. Permalink : https://e-campus.itech.fr/pmb/opac_css/index.php?lvl=notice_display&id=10413 [article]

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Water management of human hair / F.-J. Wortmann in IFSCC MAGAZINE, Vol. 10, N° 4 (10-11-12/2007)

[article]  inIFSCC MAGAZINE > Vol. 10, N° 4 (10-11-12/2007) . - p. 317-320 Titre : Water management of human hair Type de document : texte imprimé Auteurs : F.-J. Wortmann, Auteur ; Alexandra Hullmann, Auteur ; Crisan Popescu, Auteur Année de publication : 2008 Article en page(s) : p. 317-320 Note générale : Bibliogr. Langues : Anglais (eng) Tags : 'Traitements  cosmétiques'  'Coefficient  de  diffusion'  'Cheveu  humain'  Hystérèse  'Sorption  l'eau' Index. décimale : 668.5 Parfums et cosmétiques Résumé : Temperature dependent isotherms for the water ab- and desorption of human hair were determined (25–65°C) together with the related diffusion coefficients and hysteresis effects. Special care was taken to standardize the physical history of the samples. With increasing temperature, isotherms, while preserving their shape, shift to lower regains while the hysteresis effect decreases. This is in accordance with expectations derived from the Rosenbaum-model for water sorption. The differential heat of water sorption changes from dry to wet hair between 1020 and 50 J/g H2O. Diffusion coefficients are of the order of 10-9 cm2/s. The coefficients increase with temperature and show a pronounced maximum in the range of medium regains. The temperature dependence follows the Arrhenius equation and exhibits activation energies that change from dry to wet hair between 55 and 30 kJ/mol. The sorption performance of strongly bleached hair, with and without an additional treatment with cetyltrimethylammonium bromide, was investigated. No significant effects either of the cosmetic treatment or of the ingredient were found. It is concluded that human hair exhibits a rather robust static and dynamic water sorption performance that, against initial expectations, is not readily changed by cosmetic processes and ingredients. Permalink : https://e-campus.itech.fr/pmb/opac_css/index.php?lvl=notice_display&id=10414 [article]

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Super mild oxidation coloring : preventing hair damage at the molecular level / Thomas Doering in IFSCC MAGAZINE, Vol. 10, N° 4 (10-11-12/2007)

[article]  inIFSCC MAGAZINE > Vol. 10, N° 4 (10-11-12/2007) . - p. 323-329 Titre : Super mild oxidation coloring : preventing hair damage at the molecular level Type de document : texte imprimé Auteurs : Thomas Doering, Auteur ; Claudia Brockmann, Auteur ; Armin Wadle, Auteur ; Detlef Hollenberg, Auteur ; Thomas Förster, Auteur Année de publication : 2008 Article en page(s) : p. 323-329 Note générale : Bibliogr. Langues : Anglais (eng) Tags : 'Acide  alpha  lipoique'  'Anti-oxydant'  'Cheveux  abimés'  'Colorant  pour  cheveux'  'Spectroscopie  infrarouge  proche' Index. décimale : 668.5 Parfums et cosmétiques Résumé : Hydrogen peroxide is widely used for oxidation hair coloring or bleaching. It displays a high redox potential and easily penetrates into the hair fiber. This renders hydrogen peroxide capable of non-specific interactions with cortex and cuticle proteins resulting in irreversible cleavage of cystine crosslinks. Various classes of antioxidants were screened for their anti-hair damage effect in a permanent hair dye formulation using NIR spectroscopy. In parallel, the effect on the coloring and lightening performance was studied to exclude unwanted side effects on primary product performance. The screening criteria were fulfilled by organic disulfides such as α-lipoic acid but interestingly not by powerful antioxidants such as tocoperol, dibutylhydroxytoluene, or beta-carotene. Alpha-lipoic acid significantly protected human hair during oxidation coloring as demonstrated by (i) amino acid and protein analysis, (ii) surface polarity measurement, (iii) lipid analysis, (iv) differential scanning calorimetry, and (v) combing work measurement. Our results show that radical scavenging properties alone do not render antioxidants suitable for hair protection during oxidative treatments. The presence of disulfide bonds appears to be very favorable and it is likely that the intramolecular cross-link within α-lipoic acid provides a kinetically controlled protection for cystine crosslinks during oxidation coloring. Permalink : https://e-campus.itech.fr/pmb/opac_css/index.php?lvl=notice_display&id=10417 [article]

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