We study the dynamics of viscous capillary rising in small corners between two curved walls described by a function $y=cx^n$ with $n \ge 1$. Using the Onsager principle, we derive a partial differential equation that describes the time evolution of the meniscus profile. By solving the equation both numerically and analytically, we show that the capillary rising dynamics is quite universal. Our theory explains the surprising finding by Ponomarenko et al. (J. Fluid Mech., vol. 666, 2011, pp. 146–154) that the time dependence of the height not only obeys the universal power-law of $t^{1/3}$, but also that the prefactor is almost independent of $n$.

The dynamics of spreading of a macroscopic liquid droplet over a wetting surface is often described by a power-law relaxation, namely, the droplet radius increases as $t^{m}$ for time $t$, which is known as Tanner’s law. Here we show, by both experiments and theory, that when the liquid spreading takes place between a thin soap film and a glass fibre penetrating the film, the spreading is significantly slowed down. When the film thickness $\ell$ becomes smaller than the fibre diameter $d$, the strong hydrodynamic confinement effect of the soap film gives rise to a logarithmic relaxation with fibre creeping time $t$. Such a slow dynamics of spreading is observed for hours both in the measured time-dependent height of capillary rise $h(t)$ on the fibre surface and viscous friction coefficient $\unicode[STIX]{x1D709}_{s}(t)$ felt by the glass fibre in contact with the soap film. A new theoretical approach based on the Onsager variational principle is developed to describe the dynamics of thin film spreading along a fibre. The newly derived equations of motion provide the analytical solutions of $h(t)$ and contact angle $\unicode[STIX]{x1D703}(t)$, which are found to be in good agreement with the experimental results. Our work thus provides a common framework for understanding the confinement effect of thin soap films on the dynamics of spreading along a fibre.

The Osaka University Aged Twin Registry (OUATR) is the largest adult twin registry in Japan. Since its establishment in 1974, the OUATR has conducted a number of studies with particular focus on the environmental contribution to physical–cognitive–mental aging, longevity and aging-dependent diseases in later adulthood. The registry consists of 12,000 pairs of Japanese twins born between 1900 and 1935. Two hundred and fifty pairs of twins have undergone comprehensive medical examination to date. Follow-up questionnaires have been mailed out on a regular basis, for the purpose of checking current vital statuses, health conditions, and so forth. The main objective of this longitudinal twin study is to contribute to the prevention of lifestyle-related diseases and the promotion of successful aging.

More than 100 pairs of adult twins, reared apart and growing old separately, have participated in the Japanese Study of Adult Twins Reared Apart and Growing Old Separately since it began in 1974. The subjects are 161 pairs of adult twins born between 1910 and 1945 in Japan. The main focus of this study is to investigate the influences of environmental factors and life history on life satisfaction and psychological well-being in later adulthood. A mail survey has been conducted on these twins each year since 1974. To date, the Wechsler Adult Intelligent Scale, Maudsley Personality Inventory, Newgarten Life Satisfaction Index, comprehensive medical examinations and personal interviews have been conducted for 12 twin pairs residing in various areas of Japan.