Recurring Meeting of Cleveland Clinic Core Team

Date: March 29, 2016

Time: 10:30 AM EST

Means: In person meeting


  1. Ahmet Erdemir
  2. Craig Bennetts
  3. Snehal Chokhandre
  4. Tara Bonner
  5. Will Zaylor


  1. Discuss immediate action items from the last meeting.
  2. Continue evaluation of drafts for data manuscripts (Deadline for second drafts-April 1).
  3. Discuss progress of tissue testing protocol evaluation.
  4. Decide immediate action items for the next meeting.
  5. Other.

Immediate Action Items:

Ongoing Action Items:



  1. Discuss immediate action items from the last meeting.
    • Craig documented the geometry generation including resampling and treatment of different tissue types. Based on the groups quick review, the relevant specifications appeared to be complete. Ahmet requested from Craig to provide images in the specifications page for sample geometry generation for all components, a full three-dimensional geometric representation of the knee, and illustration of surface mesh density (resampling) variations. Craig committed generated geometries to the repository. He described the file naming convention, which was also summarized in the geometry generation specifications page. The files essentially appends an acronym (relevant to the processes) to the segmentation file (*.nii). Ahmet also asked Craig to generate and commit RAW stl surfaces (no smoothing, no decimation) to serve as reference geometry.
    • Craig analyzed contact pressure data files to pinpoint sensor orientation. He still needs to check pressure analysis unit matching between title and colorbar and recommit analysis plots if necessary. He also needs to talk to Robb about plotting figures for the patellofemoral joint testing manuscript.
    • Snehal implemented the repeatability testing protocol discussed in the previous meeting. She prepared two neighbouring cartilage compression samples. Each sample went through compression testing in consecutive days, following overnight relaxation. Before each test, the sample rested in water bath then its thickness was measured using OTMS. There were discrepancies in moduli of the same sample as determined from the data of day 1 versus from the data of day 2. The moduli of neighbouring samples also differed. Ahmet wondered if the find contact force was too low, therefore preventing adequate recruitment of samples. For a 5 mm diameter sample, the 0.5 g find contact force will result in a 0.00025 MPa stress and assuming a modulus of 2 MPa ~ 1/10,000 of strain. Ahmet recommended to use 5 g as the threshold for find contact, therefore set the target strain levels for stress relaxation test accordingly. Another concern was related to large noise in the ramp component of the data, e.g. in the order of 10 g. When the machine is stationary the noise in force measurements was comparable to transducer resolution, e.g. 0.5 g. When the machine is moving, the noise is larger, possibly due to vibrations of the machine that needs to be filtered (ideally after data collection following appropriate sampling of the noise due to vibrations). Snehal will conduct testing again with increased find contact force. Ahmet and Snehal will work together to see the quantify the vibrations due to machine movement.
    • Snehal also tested foam samples under unconfined compression. In follow up testing, she will increase the target strains to get the characteristic "S" shaped stress-strain curve for the sample.
    • Snehal reported static weight measurements of force transducers. They seem to be working appropriately. She still needs to talk to Martin Garon from Biomomentum, Inc. to get the 150g load cell working seamlessly.
  2. Continue evaluation of drafts for data manuscripts (Deadline for second drafts-April 1).
    • Work on manuscript has been slow. Ahmet requested the second drafts to be ready for his review in the upcoming weeks.
  3. Discuss progress of tissue testing protocol evaluation.
    • See relevant notes in the discussions of immediate action items from the last meeting.
  4. Decide immediate action items for the next meeting.
    • See Immediate Action Items above.
  5. Other.
    • Will described the upcoming tests by the Cleveland State University team which are relevant to Open Knee(s) work. These tests are scheduled for May 17 and May 24 and the Cleveland State team will need help for specimen preparation and imaging.

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