In the body of research relevant to high-performance flapping micro air vehicles (MAV), development of lightweight , compact and energy-efficient flapping mechanisms occupies a position of primacy due to its direct impact on the flight performance and mission capability. Realization of such versatile flapping mechanism with additional ability of producing thrust levels that fulfill requirements of cruising forward flight and vertical takeoff and landing (VTOL) conditions demand extensive design validation and performance evaluation. This paper presents a concerted approach for mechanism development of a 20 cm span flapping MAV through an iterative design process and synergistic fabrication options involving electrical-discharge-wire-cutting (EDWC) and injection molding. Dynamic characterization of each mechanism is done through high speed photography, power takeoff measurement, wind tunnel testing and proof-ofconcept test flights. The research outcome represents best-in-class mechanism for a 20 cm span flapping MAV with desirable performance features of extra-large flapping stroke up to 100°, minimal transverse vibrations and almost no phase lag between the wings.

Background: The indications for Oxford unicompartmental knee arthroplasty (UKA) have been investigated for decades. The use of radiological decision aids for Oxford UKA is widespread; however, recent evidence suggests that there is a high false-negative rate. The 3-Tesla (3T) magnetic resonance imaging (MRI) system is more accurate than the 1.5T MRI system and may perform even better with Stage III and IV osteoarthritis. Here, we investigated the relationship between MRI findings and patient-reported outcomes following Oxford UKA. Methods: Medical records were reviewed retrospectively for 94 patients (101 knees) receiving Oxford UKA. All patients had a preoperative 3T MRI scan, which identified full-thickness cartilage loss. Evidence of bone-on-bone lesions from plain X-ray, bone marrow edema, and medial meniscus root tear was also recorded. Clinical outcomes were assessed using the Oxford knee score (OKS), Tegner Lysholm knee scoring system (TLKSS), and Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC) six months postoperatively. Results: We reviewed 94 patients (101 knees, 30 in male patients and 71 in female patients) with full-thickness cartilage loss on 3T MRI. There were no significant differences in the TLKSS, OKS, or WOMAC between groups with and without bone-on-bone lesions, bone marrow edema, or medial meniscus root tear six months postsurgery. Conclusion: The 3T MRI system is an applicable radiographical decision aid for Oxford UKA patient selection. Full-thickness cartilage loss on 3T MRI is sufficient for identifying Oxford UKA beneficiaries, regardless of bone-on-bone lesions, bone marrow edema, or medial meniscus root tear