objectives: the main disadvantage of fiber posts is their low bond strength to root canal wall. the aim of the present study was to assess the effect of different root canal post space treatments on push-out bond strength of fiber posts to root dentin. materials and methods: after post space preparation in 40 endodontically treated human premolars, the teeth were randomly divided into four expe...

Subarachnoid hemorrhage (SAH) resulting from a ruptured intracranial aneurysm can induce cerebral vasospasm with subsequent reduction in cerebral blood flow (CBF). The present study examines the pathological alterations in the wall of human cerebral arteries at autopsy, especially with regard to intimal pathology, following aneurysmal SAH. Arterial segments from the circle of Willis were fi...

Self-sufficiency in robotics motivates the need for continual improvement in autonomous navigation for mobile robots. Wall-following provides a simplification of 2-D navigation problems by providing a reference by which these problems are reduced to 1-D. A laser scanner for wall detection (abstracted as an active tangent/curvature sensor) is used on a kinematic unicycle robot, together with a c...

myocardial free wall rupture is a catastrophic complication of acute myocardial infarction, and prognosis will depend on the prompt diagnosis by echocardiography, extension of infarct size, and prompt surgical treatment. free wall rupture concomitant with ventricular septal defect (vsd) may be more complicated for management. a case of a 69-year-old man with myocardial free wall rupture and vsd...

We study generalized wall following behavior of mobile robots using numerical simulations. We find that the dynamics are chaotic over a range of parameter values. In addition, we propose a theory of wall following where the robot-wall combination can be treated as a pendulum-like nonlinear oscillator, driven by perturbations in the environment. We compute the dominant Lyapunov exponent for a ro...