Weekly Update in lieu of Recurring Meeting of Cleveland Clinic Core Team
Date: January 24, 2017
Provided by: Snehal Chokhandre
Ongoing Action Items:
- Review drafts of data manuscripts for submission.
- Complete studies for tissue testing reproducibility.
- Continue tissue testing of Open Knee(s) specimens.
- Continue segmentation of Open Knee(s) specimens.
- Tissue testing.
- Snehal was away most of last week.
- Snehal ordered compression top plate with 5mm by 5mm rectangular chamber. This will be used to test manually cut meniscus samples in confined compression. She also requested the Prototype Laboratory to make a confined compression indenter with a 4mm wide tip. This will make sure most of the filter and sample are covered and evenly compressed during confined compression test and avoid tipping of the filter. Both the compression plate and indentor will be delivered by January 31.
Snehal also ordered two knee specimens. One > 70 years old and another < 55 years old. These will be used to conduct two sets of repeatability tests to assess any age related differences. The current repeatability tests are performed on a 40 yr old specimen and therefore the older specimen will be evaluated first. This evaluation was prompted by the cartilage compression tests performed for oks001 where both the confined and unconfined tests indicated possible tissue failure at 10-15% strain. The speculation was that this may be due to the age of the donor (71 yrs). The thickness measurement however indicated no plastic deformation. 10-15% strain was also used for preconditioning as the sample seemed to float away at lower strains. This was a deviation from the protocol. All these factors will be assessed with the repeatability trial of a specimen from an older donor. A knee specimen from a 78 year old knee specimen will be delivered by Anatomy Gifts Registry by Wednesday. Snehal will dissect the specimen on Thursday.
- In the meantime, Snehal is working on literature review for mechanical testing of cartilage, meniscus, ligaments and tendon.
- Ahmet suggested that a ramp to 15% strain at 20%/s strain rate loading-unloading step should be performed right before and after preconditioning. Snehal modified the preconditioning protocol on Mach-1 as well as the Python script for preconditioning data check to accommodate the change. All the repeatability tests going forward will incorporate this change. This ramp data will be useful in assessing the tissue state (potential failure etc) before the 1.5 hour long stress relaxation test is performed. This data will also be useful in characterizing the elastic behavior of the tissue.
- The protocol specifications will also indicate that before the ramp step is performed before and after preconditioning the indentor is kept 20 microns away from the 'find contact'/'initial length' position obtained with 10g load. This will provide options to find the actual zero displacement.
- All the repeatability tests will be preformed with full 30 mins wait after each ramp. Once the cartilage repeatability tests will all the recommended suggestions are complete, oks001 cartilage repeatability tests will be resumed.
- Data manuscripts.
- No progress.
- Connor segmented more oks001 tissues for repeatability.
- Ahmet had a meeting with Stanford University team about cloud computing. The interface for cloud computing will likely be launched this week.