A quantum kinetic equation is derived for the description of pair production in a timedependent homogeneous electric field E(t). As a source term, the Schwinger mechanism for particle creation is incorporated. Possible particle production due to collisions and collisional damping are neglected. The main result is a kinetic equation of non-Markovian character. In the low density approximation, t...

BACKGROUND Improving ankle-foot orthosis design can best be done by implementing a user-centered approach. OBJECTIVE To provide insight into the ideas of ankle-foot orthosis users with flaccid ankle muscle paresis on the importance of activities and suggestions for an improved ankle-foot orthosis design. STUDY DESIGN A focus-group discussion with eight ankle-foot orthosis users (57 ± 5 year...

Ankle sprain is one of the most commonly damaged lower extremities. More than 70% of people with ankle sprain experience chronic ankle instability. However, some people are well adapted to this damage (Coper people) and do not suffer from chronic ankle instability. The aim of this study was to compare EMG activity of the selected involved muscles in balance control strategies in athletes with c...

Abstract Background: Despite the importance of functional-performance deficits in athletes with history of ankle sprain few, studies have been carried out in this area. The aim of this research was to study relationship between previous ankle sprains and functional-performance deficits in athletes. Materials and methods: The subjects were 40 professional athletes selected through random sampl...

OBJECTIVES Ankle injuries account for the highest percentage of injuries in netball, yet the chronic nature of ankle sprains is under reported within this population group. Chronic ankle instability is a term used to describe certain insufficiencies that persist after an acute ankle sprain. The aim of this study was to investigate recurrent sprain, perceived ankle instability and mechanical ank...

iii Abstract The goal of this research is to provide a framework for vibro-acoustical analysis and design of a multiple-layer constrained damping structure. The existing research on damping and viscoelastic damping mechanism is limited to the following four mainstream approaches: modeling techniques of damping treatments/materials; control through the electrical-mechanical effect using the piez...

BACKGROUND Simultaneous motion of the knee and ankle joints is required for many activities including gait. We aimed to evaluate the influence of surgery involving tendons around the knee on ankle motion during gait in the sagittal plane in cerebral palsy patients. METHODS We included data from 55 limbs in 34 patients with spastic cerebral palsy. Patients were followed up after undergoing onl...

BACKGROUND Little information is available regarding the ankle braces orthopaedic sports medicine clinicians recommend or clinicians' concerns that may influence their decisions to recommend use of an ankle brace. HYPOTHESES (1) Clinicians most frequently recommend lace-up braces with straps. (2) Clinicians who are concerned about potential adverse side effects from ankle brace use are less l...

A technique to identifY damping parameters directly from the frequency response functions (FRF) in matrix forms has been developed. Furtl1ermore, the technique identifies the viscous damping and structural damping coefficients separately. The technique provides more accurate damping values because it does not rely on the information of the natural modes as in the conventional method. The dampin...