Anomalously weak solar convection

Convection in the solar interior is thought to comprise structures on a spectrum of scales. This conclusion emerges from phenomenological studies and numerical simulations, though neither covers the proper range of dynamical parameters of solar convection. Here, we analyze observations of the wavefield in the solar photosphere using techniques of time-distance helioseismology to image flows in the solar interior. We downsample and synthesize 900 billion wavefield observations to produce 3 billion cross-correlations, which we average and fit, measuring 5 million wave travel times. Using these travel times, we deduce the underlying flow systems and study their statistics to bound convective velocity magnitudes in the solar interior, as a function of depth and spherical-harmonic degree ℓ. Within the wavenumber band ℓ < 60, convective velocities are 20–100 times weaker than current theoretical estimates. This constraint suggests the prevalence of a different paradigm of turbulence from that predicted by existing models, prompting the question: what mechanism transports the heat flux of a solar luminosity outwards? Advection is dominated by Coriolis forces for wavenumbers ℓ < 60, with Rossby numbers smaller than approximately 10^-2 at r/R_⊙ = 0.96, suggesting that the Sun may be a much faster rotator than previously thought, and that large-scale convection may be quasi-geostrophic. The fact that isorotation contours in the Sun are not coaligned with the axis of rotation suggests the presence of a latitudinal entropy gradient.     

Bioinspired mineralization and cell adhesion on surface functionalized poly(vinyl alcohol) films

Poly(vinyl alcohol) (PVA) films, when surface functionalized by phosphorylation, induced biomimetic nucleation and growth of calcium phosphate in a simulated physiological environment. The surface phosphorylation on PVA was ensured by attenuated total reflectance infrared spectroscopy. The morphology of the calcium phosphate phase grown on surface-phosphorylated PVA (PPVA) was analysed using scanning electron microscopy coupled with an energy-dispersive X-ray detector. The primary nucleation of calcium phosphate occurs in 3 days and secondary nucleation occurs after 10 days. The energy-dispersive X-ray analysis shows that the Ca/P ratio of the coating increases with time of exposure to the simulated physiological fluid and reaches 1.67 at 10 days. The PPVA supports in vitro cell adhesion and promotes in vitro biomineralization in the presence of cells, evaluated using human osteosarcoma cells.     

Ageing of radiation-sterilized polypropylene: changes in semicrystallinity

Studies on radiation sterilization of isotactic polypropylene intended for biomedical applications were carried out for uncovered and covered samples. The effect of ageing on these samples was studied by determining the changes in relative crystallinity. The semicrystalline nature of the polymer is responsible for the changes in crystallinity. The transitions between short- and long-range order and short- and long-duration stiffness in both covered and uncovered samples, reflected in changes in relative crystallinity, were highly affected by the formation of branches in the backbone of the polymer. The high degree of branching in covered samples resulted in greater long-duration stiffness in the transition between short- and long-duration stiffness. The high degree of branching in covered samples was attributed to the high diffusion of energized oxygen into the polymer matrix compared with uncovered samples. The changes in relative crystallinity were rapid in uncovered samples (70% max; 34% min) but rather slow in covered samples (87% max; 43% min).     

Effect of protein deficiency on absorption, transport and distribution of alpha-tocopherol in the rat.

The absorption, transport and distribution of alpha-[3H]tocopherol were greatly decreased in protein deficiency. This was reflected in the subcellular distribution of alpha-[3H]tocopherol in livers of protein-deficient rats. The ratio, bound:free for alpha-[3H]tocopherol, also decreased in both serum and liver cytosol. After protein refeeding, absorption, transport and distribution patterns of alpha-[3H]tocopherol for the protein-deficient rats were restored to patterns similar to those of control animals.     

Anorexia nervosa associated with energy-wasting disorders

Some patients with anorexia nervosa and energy-wasting disorders have been found to be able to use their illness to lose weight. This paper presents two patients with diabetes mellitus and one with ulcerative colitis in whom the illness was complicated by anorexia nervosa.