Abstract: A head unit device for controlling motion of an object includes a chamber filled with a shear thickening fluid (STF) and a piston. The piston is housed within the chamber and exerts pressure against the STF from a force applied to the piston from the object. The STF is configured to have a decreasing viscosity in response to a first range of shear rates and an increasing viscosity in response to a second range of shear rates. The piston includes at least one piston bypass between opposite sides of the piston that controls flow of the STF between the opposite sides of the piston to selectively react with a shear threshold effect of the first range of shear rates or the second range of shear rates.

Abstract: A subcutaneously formed in place orthopedic fixation device is provided, such as for fixation of the spine or other bone or bones. The device comprises an inflatable member, such as a tubular balloon. The balloon is positioned at a treatment site in the body while in a flexible, low crossing profile configuration. The balloon is thereafter inflated with a hardenable epoxy media comprising one or more epoxy compounds and one or more amine curing compounds that cures rapidly in place with low to moderate exotherm. Methods and delivery structures are also disclosed.