Current keyhole biopsy devices are rather ungainly, inaccurate, and limited in application. A keyhole biopsy harvester was designed to facilitate peripheral cancerous tissue detection and resection at high speed and accuracy. The harvester's cutting tool, the crown-cutter, was bioinspired by the sea urchin's chewing organ—Aristotle's lantern. This paper focuses on the optimization of the crown-cutter with regard to the impact of different tooth quantity and bevel type on tissue deformation, penetration forces, and tooth collapsibility. Two sets of crown-cutter designs were manufactured and tested in push-in experiments using gelatin—the first set having no bevel and differing tooth quantity (4, 6, 8, 10 teeth) and the second set of constant tooth quantity and differing bevel type (no, inner, outer, and inner and outer bevel). The gelatin surface deformation and the penetration forces were evaluated utilizing a high speed camera and a universal testing machine, respectively. The experimental results on the crown-cutters of different tooth quantity (no bevel) showed a steady increase in the tissue deformation with the increasing amount of teeth. Unlike the bevel type, the different tooth quantity revealed significant differences with regard to the tissue deformation in between 4 versus 6-teeth and 10 versus 6-teeth cutters. As for the penetration forces, the significant difference was found only between 10 and 6-teeth cutters. In conclusion, reducing the cutter's tooth quantity resulted in lower tissue deformation, whereas differing the bevel type was found to have a negligible influence. Ultimately, a high ratio of outward to inward tooth collapsibility and a relatively low inner moment of inertia proved the 6-teeth cutter to be the most optimal.

For a better understanding of how different diseases (e.g. neurovascular diseases, neurodegenerative diseases, and musculoskeletal pain conditions) affect human motor function, a uniform, standardized and objective evaluation is a desirable goal expressed within the clinical community. We explore the capabilities of an augmented reality (AR) game that uses free hand interaction to facilitate an objective assessment of the upper extremity motor dysfunction. First, the design process of the game and the system architecture are described. Second, a study about usability of the AR framework and game engagement is presented based on an experiment we conducted with five patients and ten healthy people. Lastly, a short analysis of the accuracy of the hand data when participants performed "fingers tapping" gesture is done. The results of the study show that even though users experienced the system as physically and mentally demanding, it was engaging enough to make them complete the game. The study also shows that hand data captured is accurate enough to allow a high degree (95%) of pinching gesture recognition.

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