To begin, dissect the fifth lumbar vertebra isolated from the frozen mouse carcass. Using a diamond cutoff wheel attached to a rotary tool, cut each pedicle to remove the transverse and spinous processes. Gently sand the coddle end of the vertebrae using fine 120-grit sandpaper to eliminate all intervertebral discs, soft tissue, and irregularities.
Then mark the sanded coddle end with a permanent marker for easy identification later. Prepare the PMMA bone cement according to the manufacturer's instructions. Apply a small amount of the semi-soft PMMA bone cement onto the upper side of the unmarked cranial end of the vertebra and rehydrate with saline.
While the PMMA is still semi-soft, position the vertebra on the bottom platin with the coddle side facing downwards. Now turn on the machine to engage the drive gears and gradually lower the top platin onto the vertebra and PMMA bone cement complex until it contacts the bone cement. Allow the PMMA bone cement to completely harden while the top platin gently presses down on it.
In real time, use digital software designed for data collection of mechanical testing to collect data for load and displacement from the sensors into a spreadsheet. After collecting baseline data for five seconds, applied with a minimal preload force of less than 0.5 newtons. Gradually lower the top platin onto the sample at a constant and predetermined lowering speed, to initiate the compression test.
Cease data collection, once a significant reduction in load has been observed indicating material failure. Correct each data point for system displacement, using the equation obtained in previous steps. To create a load displacement curve with the load on the Y axis and the corrected specimen displacement on the X axis.
First, create a table by clicking on windows, then selecting new table, followed by do it"Copy the corrected displacement and load data from the raw data spreadsheet into the new table. Then to generate a waveform representing the raw data, click data and select XY pair to waveform. Select corrected displacement data for the X wave and load data for the Y wave, ensure the correct data points are in the number of points box.
Name the wave form, and click make wave form. After creating the wave form, visualize the load displacement curve by clicking on windows and selecting new graph. Place the waveform on the Y axis and calculate it on the X axis to generate a graph.
Use the cursor tool to mark points or regions of interest on the graph for further analysis.
