Change in surface chemistry of the cuticle of human hair by chemical and photochemical oxidation / Sigrid B. Ruetsch in IFSCC MAGAZINE, Vol. 7, N° 4 (10-11-12/2004)

[article]  inIFSCC MAGAZINE > Vol. 7, N° 4 (10-11-12/2004) . - p. 299-307 Titre : Change in surface chemistry of the cuticle of human hair by chemical and photochemical oxidation Type de document : texte imprimé Auteurs : Sigrid B. Ruetsch, Auteur ; Yash K. Kamath, Auteur Année de publication : 2004 Article en page(s) : p. 299-307 Note générale : Bibliogr. Langues : Anglais (eng) Tags : 'Chemical  and  photochemical  oxidation'  'surface  lipids  (F-layer)'  microfluorometry  'single  fiber  surface  wettability  scanning'  'fiber-to-fiber  friction  force  measurements'  'X-ray  photoelectron  spectroscopy' Index. décimale : 668.5 Parfums et cosmétiques Résumé : This is a multifaceted study on the characterization and quantification of damage to the hair fiber surface caused by photochemical and cosmetic chemical oxidative processes. Unique techniques were used, including a microfluorometric method that had been adapted to characterize and quantify the delipidation and acidification of the human hair surface during light exposure and cosmetic chemical grooming processes such as bleaching. During photochemical and chemical oxidation, breakdown of the lipid domains (also called the F-layer) of the outer b-layer occurs on the exposed scale faces and cysteic acid groups are generated on the cuticle cell surface. The newly formed acid functionalities can be tagged with the cationic fluorochrome Rhodamine B, allowing not only quantification of the level of progressive acidification but also localization of the newly formed acid functionalities. On the other hand, the negative charges generated on the hair surface by oxidation can also bind low molecular weight quaternary cationic conditioning compounds such as cetyltrimethylammonium bromide. This process can be considered a relipidation by adsorption. We have shown that the entire process of delipidation/acid formation and subsequent relipidation by adsorption on the scale faces can be quantified by X-ray photoelectron spectroscopy. Since X-ray photoelectron spectroscopy analysis is highly sensitive and able to detect atomic species at the very surface of the hair fibers, receiving signals from an escape depth as shallow as 25 Ã…, it appeared ideal for the characterization of treatment-induced changes in the hair surface. However, X-ray photoelectron spectroscopy provides an average elemental composition of the hair surface including scale faces and scale edges. The microfluorometric technique, on the other hand, can distinguish progressive delipidation of the scale faces from changes occurring at the broken scale edges. This distinction was shown and characterized in detail by slow speed microfluorometric scanning of the hair surface. Chemical and photochemical oxidative processes at the hair surface result in certain collateral effects. Particularly changes in surface wettability and fiber friction are of significance to the cosmetic chemist because they affect the spreading and wicking of products in hair as well as the managability and the body of hair assemblies. Methods of characterizing these effects are discussed briefly. Permalink : https://e-campus.itech.fr/pmb/opac_css/index.php?lvl=notice_display&id=10483 [article]

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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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Combing damage to hair cuticle structure / K. Ram Ramaprasad in IFSCC MAGAZINE, Vol. 10, N° 2 (04-05/2007)

[article]  inIFSCC MAGAZINE > Vol. 10, N° 2 (04-05/2007) . - p. 127-134 Titre : Combing damage to hair cuticle structure Type de document : document électronique Auteurs : K. Ram Ramaprasad, Auteur ; Sigrid B. Ruetsch, Auteur ; Hans-Dietrich Weigmann, Auteur ; Yash K. Kamath, Auteur Année de publication : 2007 Article en page(s) : p. 127-134 Note générale : Bibliogr. Langues : Anglais (eng) Tags : Goniophotomètre  Cheveu  Abrasion  Conditionneurs  Cuticule  'Dommage  du  peignage  sec  et  humide'  Peignage  'Dispersion  de  la  lumière' Index. décimale : 668.5 Parfums et cosmétiques Résumé : Optical probing of hair fibres is an elegant, non-invasive method to monitor the fibre surface and its changes with various grooming protocols. In this paper, a goniophotometer with a He-Ne light source was used to study reflection profiles from single hair fibres in both the root-to-tip and tip-to-root orientations of the fibre. The calculated scale angle (the inclination of the cuticle to the fibre axis) was used as a monitor to study combing damage in hair to demonstrate the usefulness of the method. It was shown that progressive dry combing of hair leads to cuticle thinning or abrasive damage, and wet combing results in cuticle breaking or ablative damage. Further, the use of a conditioner active like a polyquaternium-10 largely mitigates both types of damage. These findings were supported by the results of a parallel scanning electron microscopic study. Note de contenu : - EXPERIMENTAL : Combing - Goniophotometry - Conditioner treatment of hair - RESULTS AND DISCUSSION : Effect of dry-combing on scale angle - Effects of wet combing on scale - Effect of conditioner treatment on scale angle changes during combing Permalink : https://e-campus.itech.fr/pmb/opac_css/index.php?lvl=notice_display&id=10422 [article]

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Cuticular damage to african-american hair during relaxer treatments - A microfluorometric and SEM study - / Sigrid B. Ruetsch in IFSCC MAGAZINE, Vol. 11, N° 2 (04-05/2008)

[article]  inIFSCC MAGAZINE > Vol. 11, N° 2 (04-05/2008) . - p. 131-137 Titre : Cuticular damage to african-american hair during relaxer treatments - A microfluorometric and SEM study - Type de document : texte imprimé Auteurs : Sigrid B. Ruetsch, Auteur ; Binhua Yang, Auteur ; Yash K. Kamath, Auteur Année de publication : 2008 Article en page(s) : p. 131-137 Note générale : Bibliogr. Langues : Anglais (eng) Tags : 'African-American  hair'  'Lye-based'  'No-lye  relaxers'  'Relaxer  solutions'  'Commercial  relaxer  systems'  'Relaxer-induced  surface  changes/damage'  'Surface  chemistry'  'Physical  nature'  'Microfluorometry' Résumé : In earlier publications [1,2,3 we discussed several in-depth studies of characterization and quantification of damage done to European dark brown hair fibres by photochemical and cosmetic-chemical oxidation (bleaching) and reduction (perming) processes. These earlier studies established considerable changes in surface chemistry such as an increase in acidity and hydrophilicity. We discussed in detail the breakdown of the lipid domains (delipidation) of the outer ®-layer of the exposed scale faces and generation of anionic (sulphonic acid) groups (acidification) on the hair surface caused by these oxidative and reduction processes. The goal of this current study is to characterize and quantify the level of chemical and physical changes in the surface of African-American hair caused by various »lye-based« and »no-lye« relaxer treatments [4]. This study attempts to establish which product delivers the best »hair straightening« performance while resulting in the least chemical and physical changes in the hair surface. We again use a microfluorometric technique with the help of the cationic fluorochrome Rhodamine B to detect, map and quantify relaxer-induced changes in the surface chemistry of human hair fibre. In addition, we also use SEM at various magnifications to highlight relaxer-induced changes in the physical nature of the hair surface. We attempt to associate the level of increase in fluorescence intensity, which represents an increased level of delipidation/acidification of the hair surface, with the damage level to the hair topography, and thus, determine the least damaging cosmetic chemical process. Damage to the physical nature of the hair topography as observed by SEM shows a clear difference between treatments involving lab-made relaxer solutions and commercial relaxer systems. Permalink : https://e-campus.itech.fr/pmb/opac_css/index.php?lvl=notice_display&id=10373 [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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Photodegradation of hair of different ethnicity after 1 year of exposure to natural weatering in Arizona / Yash K. Kamath in IFSCC MAGAZINE, Vol. 9, N° 4 (10-11-12/2006)

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Role of melanin and artificial hair color in preventing photo-oxidative damage to hair / Sigrid B. Ruetsch in IFSCC MAGAZINE, Vol. 7, N° 2 (04-05-06/2004)

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