I will be travelling to Japan from the US soon to conduct a three week research program with some colleagues. I would like to bring some of the fragile research equipment with me in my carry-on. The equipment is small, fragile, and reasonably valuable, but poses no danger to people or planes. Some of the items will be coming back home with me, and some will be staying.
Are there any Japanese or American regulations which I need to be worried about? Do I need to declare the items at customs? Is there a risk that they will be confiscated at some point during my travel?