RESUMEN
We use Faraday waves to measure interfacial tension σ between two immiscible fluids, with an interest in (ultra)low values of σ. The waves are excited by vertically oscillating the container in which the fluids reside. Using linear stability theory, we map out the accessible range of interfacial tensions. The smallest value (σmin ≈ 5 × 10-4 N/m) is limited by the joint influence of gravity and viscous dissipation. A further limitation is posed by the greatest accelerations that can be realized in a laboratory. We perform experiments on a water-dodecane interface with an increasing concentration of a surfactant in the water layer that decreases the interfacial tension into the ultralow domain [σ = [Formula: see text](10-6 N/m)]. Surprisingly, the smallest measured wavelength is larger by a factor of 2 than that predicted for vanishing σ. We hypothesize the effect of transport of the surfactant in the fluid flow associated with the waves.
RESUMEN
Morindae Officinalis Radix (MOR), the dried root of Morinda officinalis F.C. How (Rubiaceae), is a popular food supplement in southeastern China for bone protection, andrological, and gynecological healthcare. In clinical use, 3-4 year old MOR is commonly used and the xylem is sometimes removed. However, there is no scientific rationale for these practices so far. In this study, metabolomics and glycomics were integrated using multiple chromatographic and mass spectrometric techniques coupled with multivariate statistical analysis to investigate the qualitative and quantitative variations of secondary metabolome and glycome in different growth years (1-7 years) and tissues (xylem and cortex) of MOR. The results showed that various types of bioactive components reached a maximum between 3 and 4 years of growth and that the xylem contained more potentially toxic constituents but less bioactive components than the cortex. This study provides the chemical basis for the common practice of using 3-4 year old MOR with the xylem removed.
