Characterization of surface and subsurface photodegradation of skin / Yash K. Kamath in IFSCC MAGAZINE, Vol. 6, N° 3 (07-08-09/2003)

[article]  inIFSCC MAGAZINE > Vol. 6, N° 3 (07-08-09/2003) . - p. 199-205 Titre : Characterization of surface and subsurface photodegradation of skin Type de document : document électronique Auteurs : Yash K. Kamath, Auteur ; Sigrid B. Ruetsch, Auteur Année de publication : 2003 Article en page(s) : p. 199-205 Note générale : Bibliogr. Langues : Anglais (eng) Catégories : Caractérisation Fluorimétrie Peau -- Effet du rayonnement ultraviolet Photovieillissement (dermatologie) Produits antisolaires Spectrophotométrie UV-Visible Index. décimale : 668.5 Parfums et cosmétiques Résumé : In this work, fluorescence and ultraviolet spectroscopic methods have been adapted to characterize photochemical damage to skin. As opposed to the usual method of quantifying skin damage by erythema (redness), in this work we have tried to distinguish between surface and subsurface damage by applying spectroscopic methods mentioned above directly to the skin specimens. Subsurface damage, especially, is known to lead to immunosuppressive effects on the skin, sometimes resulting in skin cancer. Because the study involves subsurface effects, this work has been done in vitro using Yutacan black pigskin as the model. Formation of photodegradation products and their suppression in the presence of sunscreens has been demonstrated microspectrophotometrically. Two types of sunscreens have been used in this study : 1)TiO2 and ZnO which deposit and remain on the skin surface without penetration; and 2) Benzophenone-4, which is water soluble and is able to penetrate into the skin. The results clearly indicate that the particulate sunscreens protect the surface of Benzophenone-4 protects the subsurface regions of viable epidermis. The results seem to support a free radical mechanism of photodamage, where free radicals are generated near the surface by the interaction of radiation with the substrate, including trace minerals, particulate sunscreens and water. These free radicals diffuse into the subsurface regions of the skin to cause damage. To prevent such damage, the sunscreen molecules capable of diffusing into the substrate should be present in those regions to scavenge the free radicals. Otherwise, subsurface damage will proceed unchecked in spite of the sunscreens on the surface. Permalink : https://e-campus.itech.fr/pmb/opac_css/index.php?lvl=notice_display&id=10557 [article]

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Fluorescence and scanning electron microscopic characterization of cuticle erosion in human hair / Sigrid B. Ruetsch in IFSCC MAGAZINE, Vol. 9, N° 1 (01-02-03/2006)

[article]  inIFSCC MAGAZINE > Vol. 9, N° 1 (01-02-03/2006) . - p. 29-35 Titre : Fluorescence and scanning electron microscopic characterization of cuticle erosion in human hair Type de document : texte imprimé Auteurs : Sigrid B. Ruetsch, Auteur ; Yash K. Kamath, Auteur Année de publication : 2006 Article en page(s) : p. 29-35 Langues : Anglais (eng) Catégories : Caractérisation Cheveux -- Détérioration Cuticule -- Détérioration Fluorimétrie Microscopie électronique à balayage Tags : 'Cheveu'  'Exposition  environnementale'  au  toilettage  'Usure  du  cuticule'  'Caractéristiques  phénomène  de  dommage  cheveu'  'Microfluorométrie  SEM' Index. décimale : 668.5 Parfums et cosmétiques Résumé : Environmental and natural grooming damage of hair were investigated by the microfluorometric method using Rhodamine B as the fluorescent tracer. An increase in fluorescence intensity of tracer-tagged hair as we moved from the root to middle section and trip end is indicative of weathering and progressive mechanical damage. The locus of Rhodamine B penetration and interaction occurs at the scale edge in the root end, changing to the scale face and scale edge in the middle section, and finally to the cortical cell surfaces and the intercellular cement at the tip end in long hair. The resulting increase in fluorescence emission intensity is indicative of progressive damage to the cuticular structure, ultimately resulting in the loss of the cuticular sheath. Scanning electron microscopic observations show detailed features of progressive cuticle erosion and abltion. Characteristic changes in the physical nature and shape of the cuticle cell compared to its appearance as it emerged from the follicle are indicative of environmental and mechanical damage inflicted upon hair. Change of the smoothly contoured scale edge to its jagged shape, frequent appearance of "failed endocuticular material" left behind after the inextensible A-layer and exocuticle have been chipped away, and "tear lines" or "seams", which are the loci where the surface cuticle cells were orinally attached, are indicative of progressive cuticle erosion. Permalink : https://e-campus.itech.fr/pmb/opac_css/index.php?lvl=notice_display&id=10535 [article]

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Pratique de l'analyse organique colorimétrique / Maurice Pesez / Paris : Masson (1966)

Titre : Pratique de l'analyse organique colorimétrique Type de document : texte imprimé Auteurs : Maurice Pesez, Auteur ; Jaroslav Bartos, Auteur ; Pierre Poirier, Auteur ; Léon Velluz, Directeur de publication, rédacteur en chef Editeur : Paris : Masson Année de publication : 1966 Importance : 351 p. Présentation : ill. Format : 23 cm Langues : Français (fre) Catégories : Colorimétrie Composés organiques -- Analyse Fluorimétrie Index. décimale : 547.3 Chimie organique analytique Note de contenu : 1. Alcools 2. Phénols 3. Alcoylamines 4. Arylamines 5. Structures azotées diverses 6. dérivés carbonylés 7. Acides carboxyliques et dérivés 8. Dérivés halogénés et soufrés 9. Structures insaturées 10. Dérivés hétérocycliques azotés 11. Oses et dérivés 12. Stéroïdes Permalink : https://e-campus.itech.fr/pmb/opac_css/index.php?lvl=notice_display&id=853

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0561	547.3 PES	Monographie	Bibliothèque principale	Documentaires	Disponible

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