A guidable catheter for heating or cooling fluid in a feeding vessel in a vasculature of a patient includes a heat transfer element having exterior surface irregularities to create turbulence in a surrounding fluid. The divided member 101 is allowed to float in an interface 24 between working fluid and refrigeration oil of an oil reservoir 21. The first and second chip are interconnected by one or more interconnections commonly referred to as diagonal interconnections. The formation sample is pumped into the other end chamber to first, displace the wellbore fluid from the first end chamber and, sequentially, to further compress the gas to preserve the sample phase state upon removal to the surface. Rubber seals are included on the edges of the dowels to provide spacing or a gap between the dowel and the preexisting slab to allow for lateral independent movement of the adjacent slabs, and to prevent concrete from the newly poured second slab from entering into the gap. Trial instruments are insertable into the disc space to determine a desired disc space height and to select a corresponding implant.