Influence of Long-Term Use of American Football Helmets on Concussion Risk.

In this study, to discuss the influence of concussion risk from the long-term use of American football helmets on collegiate teams, accident cases during the game are replicated based on game videos by simulations using whole-body numerical models and helmeted finite element human head models. The concussion risks caused by collisions were estimated using the mechanical parameters inside the skull obtained from finite element analyses. In the analyses, the different material properties of helmets identified by free-fall experiments using headform impactor-embedded helmets were used to represent brand-new and long-term-use helmets.

A study on the diagnostic support system of the repetitive brain concussion based on the reconstruction analysis of the accident.

In this paper the effectiveness of the support system which predicts the risk of the repetitive brain concussion is studied biomechanically. In the risk prediction system, the accident that caused the concussion is reconstructed by analyzing the game video via multibody dynamics and the resulting brain injury is calculated in detail by the finite element method. In order to calculate the aggravation of the brain injury by the repeated brain concussion, the following two methods are examined.

Strain-Rate Dependency of Axonal Tolerance for Uniaxial Stretching.

This study aims to clarify the relation between axonal deformation and the onset of axonal injury. Firstly, to examine the influence of strain rate on the threshold for axonal injury, cultured neurons were subjected to 12 types of stretching (strains were 0.10, 0.

Traffic Accidents Involving Cyclists Identifying Causal Factors Using Questionnaire Survey, Traffic Accident Data, and Real-World Observation.

The purpose of this study is to clarify the mechanism of traffic accidents involving cyclists. The focus is on the characteristics of cyclist accidents and scenarios, because the number of traffic accidents involving cyclists in Tokyo is the highest in Japan. First, dangerous situations in traffic incidents were investigated by collecting data from 304 cyclists in one city in Tokyo using a questionnaire survey.

Effect of amplitude and duration of impulsive pressure on endothelial permeability in in vitro fluid percussion trauma.

Background: Intracranial pressure changes during head impact cause brain injuries such as vasogenic edema and cerebral contusion. However, the influence of impulsive pressure on endothelial function has not yet been fully studied in vitro. In this study, we developed a pressure loading device that produced positive and negative pressures by modifying an in vitro fluid percussion model and examined the effects of the amplitude and duration of the pressures on endothelial permeability.

Combinations of hydrostatic pressure and shear stress influence morphology and adhesion molecules in cultured endothelial cells.

Endothelial cells are exposed to mechanical stimuli from blood flow and blood pressure. However, it is not yet fully understood how their simultaneous exposure affects endothelial function. Firstly, in this study we investigated the effect of combined stress on morphology of cultured human aortic endothelial cells (HAECs).

Muscle reflection human computer model in wheelchairs traveling in motor vehicles.

In this study, a human motion computer model in a wheelchair was developed to evaluate the effectiveness of a seatbelt for disabled people traveling in a motor vehicle. The human model was composed of two rigid links and three masses. This model was characterized with muscle reflection defined by Hill's equation.