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This document provides a design description of a data acquisition device that allows an alert to be issued to suggest to the driver to take a break after having subjected his body to a certain amount of acceleration and pressure changes after driving on a road with too many curves. The tests were carried out using sensors based on microelectromechanical systems. The system was strategically installed at specific points on the body of the driver and car. Several electronic arrays were carried out, like the design of a printed circuit board. The establishment of an inter-integrated circuit communication and its multiplexing to work with several devices with the same address simultaneously. Finally, in this context, the document also presents the critical velocity for each curve in the Hakone roadway, which was obtained by using a mathematical model and contrasted with data acquisition values for acceleration. The risk of skidding on a curve increases when the driver does not reduce driving velocity; only a slight variance in acceleration or environmental conditions is enough. The value of acceleration was acquired for the analysis of each curve; there is a greater possibility of skidding in curves 2 and 4 because their radius is smaller and the critical speed is approximately 60 km/h, which is very close to the driving speed. On the other hand, the deceleration value of −0.65 G read on the head accelerometer can increase fatigue symptoms such as blurry vision or dizziness. [ABSTRACT FROM AUTHOR]

Bone cortical tissues reorganize and remodel in response to tensile forces acting on them, while compressive forces cause atrophy. However, implants support most of the payload. Bones do not regenerate, and stress shielding occurs. The aim is to analyze the biomechanical behavior of a lumbar cage to study the implant's stress shielding. The ASTM E-9 standard was used with the necessary adjustments to perform compression tests on lumbar and thoracic porcine spinal vertebrae. Twelve cases were analyzed: six with the metal prosthesis and six with the PEEK implant. A mathematical model based on the Hertz contact theory is proposed to assess the stress shielding for endoprosthesis used in spine pathologies. The lumbar spacer (screw) helps to reduce the stress shielding effect due to the ACME thread. The best interspinous spacer is the PEEK screw. It does not embed in bone. The deformation capability increases by 11.5% and supports 78.6 kg more than a system without any interspinous spacer. [ABSTRACT FROM AUTHOR]