No abstract

Oculocutaneous albinism (OCA) is a rare and heterogeneous disorder characterized by hypopigmentation of the skin, hair and eyes. Thirty OCA type 6 (OCA6) patients with 24 mutations in SLC24A5 have been reported across various populations; however, only one patient has been identified in a Chinese population. This study identifies two novel SLC24A5 frame‐shift variants in two unrelated Chinese patients and both are predicted to be pathogenic by American College of Medical Genetics guidelines. The genotypes and phenotypes of all three Chinese OCA6 patients are unique compared with those identified in other populations. All of the mutations identified to date in Chinese OCA6 patients are predicted to be non‐functional, a finding that is useful in guiding genetic diagnosis and counseling for OCA6 in China.

As necessary appendages to the bird wing for flight, feathers have evolved to address the requirements of aerial locomotion. One of the recently discovered, fascinating aspects of this is their ability to recover shape and strength with hydration. This feature significantly enhances the effectiveness of a bird's flying capability as it allows for the natural restoration of feathers damaged by predators or other external forces. Herein, this capability is analyzed and it is demonstrated that the feather shaft can regain approximately 80% of its strength in the calamus, and 70% in the rachis when subject to a hydration step after being bent to failure. The matrix of the nano-composite structure within the feather shaft is thought to swell and soften when hydrated, reorienting the stiffer buckled fibers back to their original position. Upon drying, the strength is recovered. Experimental results are found to support this hypothesis, and a finite element calculation of hydration-induced recovery demonstrates the effect. Smart, self-healing composites based on approaches learned from the feather have the potential to allow for the creation of a new class of resilient materials.

Phase Transforming Cellular Materials (PXCMs) are periodic cellular materials whose unit cells exhibit multiple stable or meta-stable configurations. Transitions between the various (meta-) stable configurations at the unit cell level enable these materials to exhibit reusable solid state energy dissipation. This energy dissipation arises from the storage and non-equilibrium release of strain energy accompanying the limit point traversals underlying these transitions. The material deformation is fully recoverable, and thus the material can be reused to absorb and dissipate energy multiple times. In this work, we present two designs for functionally two-dimensional PXCMs: the S-type with four axes of reflectional symmetry based on a square motif and, the T-type with six axes of symmetry based on a triangular motif. We employ experiments and simulations to understand the various mechanisms that are triggered under multiaxial loading conditions. Our numerical and experimental results indicate that these materials exhibit similar solid state energy dissipation for loads applied along the various axes of reflectional symmetry of the material. The specific energy dissipation capacity of the T-type is slightly greater and less sensitive to the loading direction than the S-type under the most of loading directions. However, both types of material are shown to be very effective in dissipating energy.