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Nanoscale imaging and quantification of the impact of covalently linked lipids on the hair's surface / Gustavo S. Luengo in IFSCC MAGAZINE, Vol. 8, N° 4 (10-11-12/2005)

[article]  inIFSCC MAGAZINE > Vol. 8, N° 4 (10-11-12/2005) . - p. 271-276 Titre : Nanoscale imaging and quantification of the impact of covalently linked lipids on the hair's surface Type de document : texte imprimé Auteurs : Gustavo S. Luengo, Auteur ; Philippe Hallegot, Auteur ; Frédéric Leroy, Auteur Année de publication : 2005 Article en page(s) : p. 271-276 Note générale : Bibliogr. Langues : Anglais (eng) Tags : 'Science  des  surfaces'  Cheveu  'Microscopie  à  force  atomique'  'Acide  18-méthyléicosanoique' Index. décimale : 668.5 Parfums et cosmétiques Résumé : The role of 18-methyleicosanoic acid was explored using atomic force microscopy techniques. Treatment with a delipidating agent (hydroxylamine) did not change the hair's morphology but dramatically changed its surface tribological properties, providing a high resolution mapping of the delipidation effect and confirming the importance of the presence of this fatty acid. Using nanolithography we were able to gently scratch the outermost surface layer of hair. The obtained depth of penetration remained constant (12–45 Ã…) and was very close to the average length of the 18-methyl-eicosanoic acid molecule, supporting the assumed model of an ordered monolayer of 18-methyleicosanoic acid on the surface. Taken together, our results suggest that the lipid covering or its grafting strength may not be evenly distributed over the hair surface. The possibilities of combining nanolithography and an analytical method like time of flight secondary ion mass spectroscopy (ToF-SIMS) are discussed. Permalink : https://e-campus.itech.fr/pmb/opac_css/index.php?lvl=notice_display&id=10449 [article]

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Simultaneous enhancement of cosmetic function and feel via molecular investigation of stickiness / Hiroki Kudoh in IFSCC MAGAZINE, Vol. 8, N° 4 (10-11-12/2005)

[article]  inIFSCC MAGAZINE > Vol. 8, N° 4 (10-11-12/2005) . - p. 279-284 Titre : Simultaneous enhancement of cosmetic function and feel via molecular investigation of stickiness Type de document : document électronique Auteurs : Hiroki Kudoh, Auteur ; Hirokazu Iyanagi, Auteur ; Kenichi Yoshizawa, Auteur ; Sayuri Okura, Auteur ; Katsuhiko Nakamae, Auteur Année de publication : 2005 Article en page(s) : p. 279-284 Note générale : "Bibliogr." Langues : Anglais (eng) Tags : Viscosité  'Energie  libre  de  surface'  'Acrylate  fluoroalkyle'  'Second  coefficient  virial'  'Coefficient  d'autodiffusion'  Glycérine Index. décimale : 668.5 Parfums et cosmétiques Résumé : Moisturizing performance is often a very important factor in cosmetics. However, incorporating high concentrations of moisturizing agents often causes products to become sticky, a feel that consumers dislike. We suspected that the reason why high moisturizer content generates strong stickiness is that the polar group of the molecule is exposed to the surface. Thus, we began with the hypothesis that stickiness could be prevented through coexistence with a substance minimizing the exposure of the polar group. Using glycerin as a moisturizing agent, we screened a large number of conventional materials for reducing stickiness but failed to find an effective compound. We then considered the use of a polymer for this purpose, and synthesized a custom-made polymer, polyglycolmethacrylate-2-hydroxyethylmethacrylate-fluoroalkylacrylate copolymer (Polymer SR). Our experiments revealed that Polymer SR reduces the stickiness of glycerin by forming a hydrophobic film without hindering moisturizing performance. To clarify the mechanism by which Polymer SR restrains stickiness, we investigated the interaction between the Polymer SR and glycerin in solution form with NMR and static light-scattering measurements. We learned that Polymer SR and glycerin exist on skin as the hydrophobic group of Polymer SR orients to the outside. Subjective sensory tests supported our belief that this hydrophobic orientation is maintained on the dermal surface even after application to the skin. We believe that our technique for restraining the stickiness of moisturizers can be adopted for use with other substances by taking into account the intended function and feel, and will contribute to future cosmetic research. Permalink : https://e-campus.itech.fr/pmb/opac_css/index.php?lvl=notice_display&id=10450 [article]

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Comparative topical absorption and antioxidant effectiveness of two forms of coenzyme Q10 after a single dose and after long-term supplementation in the skin of young and middle-aged subjects / Joe Vinson in IFSCC MAGAZINE, Vol. 8, N° 4 (10-11-12/2005)

[article]  inIFSCC MAGAZINE > Vol. 8, N° 4 (10-11-12/2005) . - p. 287-292 Titre : Comparative topical absorption and antioxidant effectiveness of two forms of coenzyme Q10 after a single dose and after long-term supplementation in the skin of young and middle-aged subjects Type de document : texte imprimé Auteurs : Joe Vinson, Auteur ; Sunil Anamandla, Auteur Année de publication : 2005 Article en page(s) : p. 287-292 Note générale : Bibliogr. Langues : Anglais (eng) Tags : 'Coenzyme  Q10'  'Peau  humaine'  'Péroxydes  lipidiques'  Antioxydants  'Stratum  corneum' Index. décimale : 668.5 Parfums et cosmétiques Résumé : Coenzyme Q10 is an endogenous antioxidant found in the skin along with vitamins A, C and E. Coenzyme Q10 is used increasingly in cosmetic products and is advertised as a skin energizer, protector against skin aging, skin repairer, and an anti-wrinkling agent. As the outermost layer of skin, the stratum corneum is the interface between the body and the environment and requires antioxidants to protect it and the epidermis and dermis below it. Nutrient levels in the stratum corneum correlate with those in the skin. Two forms of coenzyme Q10 (pure coenzyme Q10 and a yeast-based coenzyme Q10) were investigated in a commercial vehicle. Two groups of subjects were tested aged 21-29 and 51-70, respectively. Coenzyme Q10 absorption in the stratum corneum was determined after a 1-hour application and ethanol extraction. Significantly more yeast coenzyme Q10 was absorbed than the pure coenzyme Q10 and the middle-aged subjects absorbed about twice as much coenzyme Q10 as did the younger subjects. Skin antioxidants were significantly increased by yeast coenzyme Q10 but not by pure coenzyme Q10. Peroxides declined in the stratum corneum after twice daily application of coenzyme Q10 with both forms but the decrease was greater with the yeast form. The older subjects had significantly higher baseline levels of lipid peroxides than did the younger group, indicating an increase in skin oxidative damage with age. The yeast coenzyme Q10 is the superior form of coenzyme Q10 for human skin application. Permalink : https://e-campus.itech.fr/pmb/opac_css/index.php?lvl=notice_display&id=10451 [article]

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Control of melanosome transfer by promoting shrinkage or expansion of melanocyte dendrites / Akihiro Tada in IFSCC MAGAZINE, Vol. 8, N° 4 (10-11-12/2005)

[article]  inIFSCC MAGAZINE > Vol. 8, N° 4 (10-11-12/2005) . - p. 293-299 Titre : Control of melanosome transfer by promoting shrinkage or expansion of melanocyte dendrites Type de document : texte imprimé Auteurs : Akihiro Tada, Auteur ; Akiko Kanamaru, Auteur ; Yuko Ito, Auteur Année de publication : 2005 Article en page(s) : p. 293-299 Note générale : Bibliogr. Langues : Anglais (eng) Tags : 'Méthylophiopogonanone  B  Centaureidine  Méthylswertianine  'Dentrites  de  mélanocyte'  'Extrait  consoude' Index. décimale : 668.5 Parfums et cosmétiques Résumé : Melanosomes synthesized within melanocytes are transferred to keratinocytes through melanocyte dendrites, resulting in a constant supply of melanin to the epidermis which determines skin pigmentation. Theoretically, if we can find an effective way to control this supply of melanin to the epidermis, skin colour could be darkened or lightened. The objective of this study was to find safe and effective methods to inhibit or promote melanosome transfer by the shrinkage or expansion of melanocyte dendrites. Methylophiopogonanone B and centaureidin inhibited melanosome transfer to keratinocytes as well as melanocyte dendrite outgrowth. Methylswertianin and comfrey extract promoted not only melanosome transfer to keratinocytes but also expansion of melanocyte dendrites. Methylophiopogonanone B and centaureidin suppressed pigmentation in a three-dimensional skin culture model through the inhibition of melanocyte dendrite outgrowth. Methylswertianin and comfrey extract activated pigmentation in a three-dimensional skin culture model by expansion of melanocyte dendrites. Our experimental findings suggest the possibility of manipulating human skin colour by controlling melanosome transfer to cause shrinkage or expansion of dendrites. A combination of effective agents, in addition to the ones identified in this work, could result in the creation of very unique cosmetic products that would precisely control the darkening or lightening of skin tone. Permalink : https://e-campus.itech.fr/pmb/opac_css/index.php?lvl=notice_display&id=10452 [article]

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Technological strategies to improve photostability of a sunscreen agent / Paola Perugini in IFSCC MAGAZINE, Vol. 8, N° 4 (10-11-12/2005)

[article]  inIFSCC MAGAZINE > Vol. 8, N° 4 (10-11-12/2005) . - p. 301-305 Titre : Technological strategies to improve photostability of a sunscreen agent Type de document : texte imprimé Auteurs : Paola Perugini, Auteur ; Manuela Vettor, Auteur ; Rosanna Tursilli, Auteur ; Santo Scalia, Auteur ; Ida Genta, Auteur ; Tiziana Modena, Auteur ; Franca Pavanetto, Auteur ; Bice Conti, Auteur Année de publication : 2005 Article en page(s) : p. 301-305 Note générale : Bibliogr. Langues : Anglais (eng) Tags : 'Produits  de  protection  solaire'  'Photodégradation  d'agent  '2-éthylhexyl-p-méthoxycinnamate'  Nanoparticules Index. décimale : 668.5 Parfums et cosmétiques Résumé : Due to the reduction of the ozone layer, there is an increasing need of effective UV protection systems with minimised side-effects. Trans-2-ethylhexyl-p-methoxycinnamate (trans-EHMC) represents one of the most widely used sunscreen compound. Several studies demonstrated that trans-EHMC is unstable following UV irradiation both in solution and in emulsion formulations. Moreover, various reports of photocontact sensitization induced by trans-EHMC have appeared in the literature. Consequently, in order to ensure adequate efficacy and safety for this sunscreen agent, there is a need for new carrier systems to enhance trans-EHMC photostability. In the present study the photostability of the filter in different formulation types (emulsion-gel, gel and emulsion) with various ingredients is evaluated. In addition, nanoparticles based on poly-D,L-lactide-co-glycolide (PLGA) as carrier for trans-EHMC are investigated. The influence of nanoparticle matrix on the photochemical stability of the sunscreen agent is also presented. The results obtained demonstrated that PLGA nanoparticles are effective in reducing the light-induced degradation of the sunscreen agent. Moreover, the choice of formulation type and the excipients used play an important role in order to obtain a stable cosmetic product containing trans-EHMC. Permalink : https://e-campus.itech.fr/pmb/opac_css/index.php?lvl=notice_display&id=10453 [article]

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