ABSTRACT
Objective To explore the influence of child head injury under different impact angles by applying the finite element model of six-year-old child pedestrian as specified in the European New Car Assessment Programme (Euro NCAP). Methods Based on the finite element model of 6-year-old pedestrian with detailed anatomical structure as specified by the Euro NCAP (TB024), four groups of simulation experiments were set up to explore the mechanism of head injury in children under different impact angles. The initial position for head mass center was on the longitudinal center line of the car. The initial speed of the car was 40 km/h. The car contacted with the model from the direction of the right (0°), the front (90°), the left (180°) and the back (270°). The kinematics differences and head impact responses were compared, and injuries of the facial bone and skull were analyzed. Results Through the analysis of head contact force, acceleration of head mass center, resultant velocity of head mass center with the vehicle, head injury criterion (HIC15), facial bone fracture and skull stress distribution, it was found that the risk of head fracture and brain contusion under back impact and front impact was higher than that under side impact. The risk of head fracture and brain contusion was highest under back impact, while the lowest under side impact. Conclusions Child pedestrian head injury was the largest under back impact. The results have important application values for the assessment and development of car-pedestrian collision protection device.
ABSTRACT
Objective To explore the relationship of plasma norepinephrine (NE) and epinephrine (E) level with TCM syndrome differentiation of attention deficit hyperactivity disorder (ADHD) in children. Methods Plasma NE and E levels in 80 ADHD children (Group A) and 32 normal volunteers (Group B) were measured by the method of high performance liquid chromatography_electrochemical detectio n (HPLC_ECD). Among 80 ADHD children, 49 were differentiated with kidney_yin def iciency and liver_yang hyperactivity syndrome (Group A 1) and 31 with heart_sp leen deficiency syndrome (Group A 2). Results Plasma NE and E levels in Gro up A we re higher than Group B (P 0.05 ). Conclusion Hyperactivity and impulsi veness in ADHD children may be related with the high levels of plasma NE and E. The exc essively sympathetic excitement in ADHD with kidney_yin deficiency and liver_yan g hyperactivity syndrome is uncertain.