No abstract

No abstract

No abstract

Over the past decade, there has been an increase in the intentional design of meso-structured materials that are optimized to target desired material properties. This paper reviews and critically compares common numerical methodologies and optimization techniques used to design these meso-structures by analyzing the methods themselves and published applications and results. Most of the reviewed research targets mechanical material properties, including effective stiffness and crushing energy absorption. The numerical methodologies reviewed include topology and size/shape optimization methods such as homogenization, Solid Isotropic Material with Penalization, and level sets. The optimization techniques reviewed include genetic algorithms (GAs), particle swarm optimization (PSO), gradient based, and exhaustive search methods. The research reviewed shows notable patterns. The literature reveals a push to apply topology optimization in an ever-growing number of 3-dimensional applications. Additionally, researchers are beginning to apply topology optimization and size/shape optimization to multiphysics problems. The research also shows notable gaps. Although PSOs are comparable evolutionary algorithms to GAs, the use of GAs dominates over PSOs. These patterns and gaps, along with others, are discussed in terms of possible future research in the design of meso-structured materials.

Objective: To determine temperature and duration of cooling necessary for achieving cochlear mild therapeutic hypothermia (MTH) via ear canal cooling using cool water and earmold attached to a Peltier device. Study Design and Setting: Human temporal bone lab study performed at the University of Mississippi Medical Center. Interventions: Cochlear cooling via the ear canal using water irrigation and an earmold attached to a Peltier device. Temperature analysis through implanted thermal probes within the cochlea. Main Outcome Measures: Temperature changes in the cochlea. Results: Irrigation of the ear canal with water resulted in achieving MTH in approximately 4 minutes using cool water (30°C) and in approximately 2 minutes using ice-chilled water. After 20 minutes, irrigation of the ear canal using cool water plateaued at a Δ2°C while cooling with ice-chilled water results in an average Δ4.5°C. We observed MTH using a medium-length earmold attached to a Peltier device after approximately 22 minutes of cooling and achieved a maximal average Δ of 2.3°C after 60 minutes of cooling. Finally, we observed that a longer earmold (C2L) with greater proximity to the eardrum resulted in more efficient intracochlear temperature change, achieving MTH in approximately 16 minutes. Conclusions: MTH of the cochlea can be achieved with water-based ear canal irrigation and via a Peltier device connected to an aluminum earmold.