For the elastodynamic simulation of a geometrically exact beam, a variational integrator is derived from a PDE viewpoint. Variational integrators are symplectic and conserve discrete momentum maps and since the presented integrator is derived in the Lie group setting (unit quaternions for the representation of rotational degrees of freedom), it intrinsically preserves the group structure withou...

Standard nonlinear schemes for the the simulation of elastodynamic problems have several shortcomings when considering high-speed rotations. To tackle these problems, we use a corotational framework and a corresponding specific linearization to design new energy-conserving numerical schemes. In the two-dimensional case, an algorithm preserving also angular momentum is presented. The existence o...

Surgical simulation is the coming training method for medical education. The main reasons for this are the reduced risk for the patients and the easy repeatability of complicated surgical procedures. Therefore, an improved impression of reality during the simulated training must be obtained. For this, a complex model of the human’s anatomy and physiology is needed. With regards to pathological ...

BACKGROUND The causative role of diffuse macular edema in various etiologies is often undetermined. OBJECTIVES To describe an association between extrafoveal vitreous traction and non-diabetic diffuse macular edema secondary to various ocular entities. METHODS In a retrospective study of eyes with non-diabetic diffuse macular edema, charts and optical coherence tomography scans demonstratin...

We performed this study to evaluate the effect of cavernous nerve (CN) traction on erectile function in rats. Thirty-two 8- week-old Sprague-Dawley rats were divided into four groups: control, 1-minute CN traction, 2-minute CN traction, and 2-minute CN crush. CN traction was performed using a glass hook with a tensile force of 0.2 Newton. One month later, the mean arterial pressure (MAP) and in...

Small intestinal intraluminal pressure activity and aboral traction forces were explored in 19 healthy volunteers using a combined manometry and traction force detecting assembly sited in the upper small intestine. Each aboral traction event was classified as being associated with either a propagating or a stationary contraction and its force measured. During phase I no contractions or traction...

Professionals who resist and restrict the indication of orthodontic traction, especially canine traction, often justify their stance by citing the following reasons: 1) Lateral Root Resorption in lateral incisors and premolars. 2) External Cervical Resorption of canines due to canine traction. 3) Alveolodental ankylosis of the canine(s) involved in the process. 4) Calcific metamorphosis of the ...

To understand how the mechanical properties of tissues emerge from interactions of multiple cells, we measure traction stresses of cohesive colonies of 1-27 cells adherent to soft substrates. We find that traction stresses are generally localized at the periphery of the colony and the total traction force scales with the colony radius. For large colony sizes, the scaling appears to approach lin...