Acetyl zingerone : An efficacious multifunctional ingredient for continued protection against ongoing DNA damage in melanocytes after sun exposure ends / Ratan K. Chaudhuri in INTERNATIONAL JOURNAL OF COSMETIC SCIENCE, Vol. 42, N° 1 (02/2020)  

[article]  inINTERNATIONAL JOURNAL OF COSMETIC SCIENCE > Vol. 42, N° 1 (02/2020) . - p. 36-45 Titre : Acetyl zingerone : An efficacious multifunctional ingredient for continued protection against ongoing DNA damage in melanocytes after sun exposure ends Type de document : texte imprimé Auteurs : Ratan K. Chaudhuri, Auteur ; T. Meyer, Auteur ; S. Premi, Auteur ; D. Brash, Auteur Année de publication : 2020 Article en page(s) : p. 36-45 Note générale : Bibliogr. Langues : Anglais (eng) Catégories : Acétyl zingerone Antioxydants Dermo-cosmétologie Dimères cyclobutyliques de pyrimidine Mélanocytes Peau -- Soins et hygiène Photoprotection Produits antisolaires Rayonnement ultraviolet Index. décimale : 668.5 Parfums et cosmétiques Résumé : - Objective : Recent research has shown that significant levels of cyclobutane pyrimidine dimers (CPDs) in DNA continue to form in melanocytes for several hours in the dark after exposure to ultraviolet radiation (UVR) ends. We document the utility of a new multifunctional ingredient, 3-(4-hydroxy, 3-methoxybenzyl)-pentane-2,4-dione (INCI acetyl zingerone (AZ)), to protect melanocytes against CPD formation after UVR exposure ends. - Methods : The use of AZ as an intervention to reduce CPD formation after irradiation was assessed in vitro by comparing kinetic profiles of CPD formation for several hours after irradiation in cells that were untreated or treated with AZ immediately after irradiation. Multifunctional performance of AZ as an antioxidant, quencher and scavenger was established using industry-standard in vitro chemical assays, and then, its efficacy in a more biological assay was confirmed by its in vitro ability to reduce intracellular levels of reactive oxygen species (ROS) in keratinocytes exposed to UVA radiation. Molecular photostability was assessed in solution during exposure to solar-simulated UVR and compared with the conventional antioxidant a-tocopherol. - Results : Even when added immediately after irradiation, AZ significantly inhibited ongoing formation of CPDs in melanocytes after exposure to UVA. Incubation with AZ before irradiation decreased intracellular levels of UVA-induced ROS formation in keratinocytes. Compared with a-tocopherol, the molecular structure of AZ endows it with significantly better photostability and efficacy to neutralize free radicals (.OH, .OOH), physically quench singlet oxygen (1O2) and scavenge peroxynitrite (ONOO-). - Conclusion : These results designate AZ as a new type of multifunctional ingredient with strong potential to extend photoprotection of traditional sunscreens and daily skincare products over the first few hours after sun exposure ends. Note de contenu : - MATERIALS AND METHODS : Acetyl zingerone - Method of analysis by HPLC - Measurement of dark-CPD formation in melanocytes - Measurement of absorbance spectrum - Measurement of intracellular ROS in keratinocytes - In vitro determination of efficiencies to neutralize key ROS - Physical quenching of singlet oxygen (1O2) - Photochemical stability - RESULTS : Acetyl zingerone (AZ) significantly reduces dark-CPD formation within 1h after UVA exposure in melanocytes - Acetyl zingerone (AZ) significantly reduces intracellular ROS formation in keratinocytes after UVA exposure - Acetyl zingerone (AZ) possesses negligible absorbance in the UV spectral region - Acetyl zingerone (AZ) is an effective antioxidant, scavenger of peroxynitrite and physical quencher of 1O2 - Acetyl zingerone (AZ) is more photochemically stable than a-tocopherol DOI : 10.1111/ics.12582 En ligne : https://drive.google.com/file/d/1lUafPqltgREXBxkkduHLJ-_d2UjqSQQM/view?usp=drive [...] Format de la ressource électronique : Pdf Permalink : https://e-campus.itech.fr/pmb/opac_css/index.php?lvl=notice_display&id=33677 [article]

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The influence of different melt temperatures on the mechanical properties of injection molded PA-12 and the post process detection by thermal analysis / T. Meyer in INTERNATIONAL POLYMER PROCESSING, Vol. XXXII, N° 1 (03/2017)  

[article]  inINTERNATIONAL POLYMER PROCESSING > Vol. XXXII, N° 1 (03/2017) . - p. 90-101 Titre : The influence of different melt temperatures on the mechanical properties of injection molded PA-12 and the post process detection by thermal analysis Type de document : texte imprimé Auteurs : T. Meyer, Auteur ; A. Harland, Auteur ; B. Haworth, Auteur ; C. Holmes, Auteur ; T. Lucas, Auteur ; P. Sherratt, Auteur Année de publication : 2017 Article en page(s) : p. 90-101 Note générale : Bibliogr. Langues : Anglais (eng) Catégories : Analyse des défaillances (fiabilité) Analyse thermique Essais de résilience Essais dynamiques Matières plastiques -- Moulage par injection Polyamide 12 Polymères -- Effets de la température Polymères -- Fusion Traction (mécanique) Index. décimale : 668.4 Plastiques, vinyles Résumé : Polyamide 12 (PA-12) test plates were injection molded using different melt temperatures and the influence on mechanical properties was investigated using quasi-static tensile and instrumented impact behavior in two conditioned states: dried, and following accelerated moisture intake. Energy absorption in tension is strongly dependent on process temperature (variations up to 99%) and additional variation (around 18%) was evident when testing at different conditioning states. Under high-velocity loading, the total impact energy varied by up to 8.70% and 9.05%, when systematic changes were made to process melt temperature and at moisture content, respectively, with all samples failing ductile. Differential Scanning Calorimetry (DSC) was used to characterise the unique endothermic melting behavior of molded PA-12 samples, by linking different process histories to the respective mechanical properties. With focus on the first heating curve progression, significant changes within the endothermic melting region were pointed out and quantified by using MatLab (software), proving DSC as a reliable testing tool for post-production analysis with increased practical implications regarding quality control as well as failure analysis. Findings for the initial heating curve progression were explained by studying the re-crystallisation peak values during cooling phase and obtained data for the second heating. Note de contenu : - INTRODUCTION AND RESEARCH OBJECTIVES - EXPERIMENTAL : Materials and injection molding - Sample preparation and conditioning - Quasi-static tensile testing - Instrumented falling weight impact testing - Analysis using differential scanning calorimetry (DSC) - Data processing - RESULTS AND DISCUSSION : Observation from processing - Influence on tensile behavior - Process influence on impact behavior - Differential scanning calorimetry DOI : 10.3139/217.3288 En ligne : https://drive.google.com/file/d/1t074OZbPAAbUIzy7Or3x3eDYGxl6dsd1/view?usp=drive [...] Format de la ressource électronique : Pdf Permalink : https://e-campus.itech.fr/pmb/opac_css/index.php?lvl=notice_display&id=28005 [article]

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