Tobacco smoke and UV radiation are extrinsic risk factors for accelerated skin ageing. In this study the effects of smoking on wrinkling and ageing were assessed in males living in Northern Finland, where cumulative sun exposure is low. Smoking habits, age and facial wrinkling were estimated from facial photographs of 41 smokers and 48 non-smokers by eight panellists, using a blinded standardiz...

Wrinkling phenomena control the surface morphology of many technical and biological systems. While primary wrinkling has been extensively studied, experimentally, analytically and computationally, higher-order instabilities remain insufficiently understood, especially in systems with stiffness contrasts well below 100. Here, we use the model system of an elastomeric bilayer to experimentally ch...

Skin aging is continuously influenced by various internal and external factors such as the biologic progression of cells, ultraviolet (UV) radiation, tobacco, nutritional deficiencies, and hormonal imbalances that lead to the degradation of skin cells. Through the degradation of skin cells, free radicals and inflammation weaken repair mechanisms and result in collagen and elastic fiber breakdow...

This paper considers an idealised solar sail consisting of a uniform, elastic, isotropic square membrane that is prestressed by two pairs of equal and opposite forces applied at the corners. Two wrinkling regimes are identified. The first regime occurs for symmetric and moderately asymmetric loading; it is characterised by small, radial corner wrinkles. The second regime occurs for strongly asy...

A systematic investigation is presented of grain boundaries and grain boundary networks in two dimensional flexible membranes with crystalline order. An isolated grain boundary undergoes a buckling transition at a critical value of the elastic constants, but, contrary to previous findings, the shape of the buckled membrane is shown to be asymptotically flat. This is in general not true in the c...

A 65-year-old male presented with right hemiparesis and skin lesions. On examination, the patient had multiple, discrete, skin-colored papules on the neck and upper chest with wrinkling of the skin. The lateral part of the trunk and medial aspect of both upper arms showed atrophic plaques. A computerized tomography scan of the head showed dilatation of the basilar artery with a frontoparietal i...

A healthy 23-year-old woman presented with a six-month history of white lesions on her palms. The lesions would swell after being in water for 15 minutes and return to baseline 10–15 minutes after drying. The patient did not take medications except for oral contraceptive pills, and she was not aware of a family history of similar complaints. Physical examination showed white, slightly transluce...

Mechanics of tympanic membrane (TM) is crucial for investigating the acoustic transmission through the ear. In this study, we studied the wrinkling behavior of tympanic membrane when it is exposed to mismatched air pressure between the ambient and the middle ear. The Rayleigh-Ritz method is adopted to analyze the critical wrinkling pressure and the fundamental eigenmode. An approximate analytic...

Wrinkling and fracture are the important defects in deep drawing operation, which can be prevented using blank holding force (BHF) which has to be optimized as lower BHF promotes wrinkles formation and higher BHF promotes fracturing. Hence the limits of wrinkling and fracture have to be established. These limits depend on various tooling and process parameters. In this work the effect of toolin...

In this paper, the anisotropic thermal conductivity characteristics of graphene wrinkles are observed for the first time using a non-equilibrium molecular dynamics method. Our results reveal that the wrinkling level has little effect on the thermal conductivity along the wrinkling direction. However, the wrinkling level plays an important role in the reduction of thermal conductivity along the ...