Obama & Medvedev in Singapore for APEC summit, Source
Physical signal interpretation: Their eyes seem friendly though Barack's clenched jaw-area seems telling. I can't tell who's squeezing whose hand tighter (though it's definitely an intense hand-shake - look at that grippin'). Medvedev appears somewhat more relaxed than Barack, with (what appears to be) confidence in his gaze towards him. Anything else you're picking up here?
Or as Lainey calls it, "Photo Assumption"