Thanks for some nice designs. #35-#39 are based on an eye logo that looks too much like a fish. What I did like about them was the metallic plate idea, and the reversed metallic plate. #40 and #41 are really really interesting. #40 incorporates an element that no one, to this point, has used: people. I think it's great to involve the human element that might make our target realize that such an institute is based primarily on our staff and their skills. Also, we're a group practice with several doctors, and this element helps to distinguish us from the solo practices that we compete against. At the same time, the logo has a little bit of an eye shape. I wonder if you could increase the focus on the eye shape, while maintaining the 'human' element...
#41 is very simple, but very effective.