Research on the biomechanics of bone and diatoms.

Research on the biomechanics of bone

　Within bones, a structure resembling slender columns can be observed. These are referred to as trabeculae, and their orientation often aligns with the principal stress directions inside beams subjected to evenly distributed loads at their ends. This observation has long suggested that bones are designed to achieve maximum strength with minimal material (Figure 1). Additionally, bones are believed to dynamically alter their internal structures and external shapes to constantly adapt to mechanical environments. Therefore, from a mechanical engineering perspective, bones can be considered dynamically optimal structures that sense mechanical stimuli and maintain their structure optimally. This study aims to induce an optimal structure that adapts to its environment artificially by cultivating immature bones under various mechanical conditions.

Figure 1. Diagram of trabeculae within the femur (left) and the calculated optimal structure under uniformly distributed load at the tip (right).

Research on the formation of frustules under mechanical loading in diatoms.

The diatom, a plant cell, possesses a siliceous frustule with intricate and delicate patterns composed of pores (areolae) on the cell wall, each measuring several micrometers. Diatoms create this complex structure solely from natural elements such as sunlight, air, water, and silicon found in the environment. Understanding the formation mechanism of these frustules with such characteristics could potentially lead to the establishment of environmentally friendly new microfabrication techniques by allowing desired forms to be artificially created. Therefore, this study investigates the detailed changes in morphology and the formation process when mechanical stress is applied to elongated diatoms like Aulacoseira, using them as examples.

Figure 2. Fluorescent image of the surface of Aulacoseira frustule.