Textbooks and policy documents tend to present the boundary between normal and abnormal ageing as natural and clearly demarcated. In this study, we trouble the notion of natural and clearly demarcated boundaries between normal and abnormal ageing by considering how these boundaries have been established and maintained in present-day Western contexts. We draw on both Canguilhem's discussion of t...

We report a dynamical-mechanical study of stress relaxation at small deformation in a natural (polyisoprene) rubber well above its glass transition temperature Tg. We find that an almost complete relaxation of stress takes place over very long relaxation periods, even though the elastic network is retained. The relaxation rate and the long-time equilibrium modulus are sensitive functions of tem...

The fact that the skin is the most visible organ makes us aware of the ageing process every minute. The use of plant extracts and herbs has its origins in ancient times. Chronological and photo-ageing can be easily distinguished clinically, but they share important molecular features. We tried to gather the most interesting evidence based on facts about plants and plant extracts used in antiagi...

The expanding range of natural actives in mainstream cosmetic products that support healthy skin aging, is ample proof that the industry now relies heavily on these ingredients. Recent scientific evidence has served to strengthen the concept of phytonutrients and validate their efficacy at the molecular level in keratinous tissues. These findings, along with successful clinical studies, have he...

The age hardening process of a 6082 Al–Mg–Si alloy by isothermal ageing at 100, 125 and 150 °C for 0 to 40 days has been investigated by both conventional and high-resolution transmission electron microscopy. Changes in sizes and densities of the pre-β and β phases during ageing can explain the evolution of hardness, in particular a plateau in the curve of the hardness versus ageing time. Fully...