BACKGROUND Many clinical studies have focused on clinical pain scores and less on kinematics following intervertebral disc replacement. Although flexion and extension of the motion segment can be measured on lateral X-rays, measuring lateral bending and axial rotation of the device is extremely difficult on plain radiography. This study was designed to measure, using radiostereometric analysis ...

We introduce a model for microtubule (MT) mechanics containing lateral bonds between dimers in neighboring protofilaments, bending rigidity of dimers, and repulsive interactions between protofilaments modeling steric constraints to investigate the influence of mechanical forces on hydrolysis and catastrophes. We use the allosteric dimer model, where tubulin dimers are characterized by an equili...

Membrane shape parameters such as curvature, bending elasticity, and lateral tension, are relevant to the lateral organization and function of biomembranes, and may critically influence the formation of lateral clustering patterns observed in living cells. Fluorescence laser-scanning microscopy can be used to image vesicles and cell membranes, and from shape analysis of these images mechanical ...

OBJECTIVE This study investigated the effects of task precision demands on behavioral and physiological changes during repetitive asymmetric lifting. BACKGROUND Repetitive lifting encountered in manual material handling leads to muscle fatigue and is a documented risk factor for low back disorder. METHOD A total of 17 healthy volunteers performed repetitive asymmetric lifting for 60 min (10...

The intrinsic function of the brain stem-spinal cord networks eliciting the locomotor synergy is well described in the lamprey-a vertebrate model system. This study addresses the role of tectum in integrating eye, body orientation, and locomotor movements as in steering and goal-directed behavior. Electrical stimuli were applied to different areas within the optic tectum in head-restrained semi...

BACKGROUND Biomechanical investigations of spinal motion preserving implants help in the understanding of their in vivo behavior. In this study, we hypothesized that the lumbar spine with implanted total spinal segment replacement (TSSR) would exhibit decreased dynamic stiffness and more rapid energy absorption compared to native functional spinal units under simulated physiologic motion when t...

OBJECTIVE In pedestrian traumas, lower limb injuries occur under lateral shearing and bending at the knee joint level. One way to improve injury mechanisms description and consequently knee joint safety is to evaluate the ultimate shearing and bending levels at which ligaments start being injured. METHODS As such data cannot easily and accurately be recorded clinically or during experiments, ...

The consideration of biomechanical alterations due to intervertebral disc (IVD) degeneration is crucial for the accurate analysis of spine biomechanics. In this study, finite element (FE) models of the L4-L5 functional spinal unit with full coverage of the degeneration grades from healthy IVD to severe degeneration were developed. The effects of IVD degeneration on spine biomechanics were analy...

The pattern of electromyographic activity in the epaxial muscles of walking and running lizards (water monitors, Varanus salvator) was quantified with high-speed video and synchronized electromyography. Muscle denervation experiments were performed and ground reaction forces were recorded to evaluate hypotheses of muscle function. Water monitors exhibit unilateral, uniphasic activation of the e...

To understand the mechanical behavior of fast-starting fish, we modeled the pumpkinseed sunfish, Lepomis gibbosus, as a longitudinally-loaded beam that behaves as an elastic column eccentrically-loaded by lateral musculature. Since bending moments are a function of the shape of the body, we used real sunfish to determine, (1) from cross-sections, the effective moment arm of the lateral musculat...