The boy here is meant to have amnesia and in a hospital after being dragged out of the Thames. The various symbology is alchemical in nature - the triangle around him is the symbol for water, the cross and snake is the flammel which is used by hospitals (and ties to alchemist Nicholas Flammel). The visible brain represents memory loss and X-rays.

The Unicorn relates to the NOAH corporation's 'Project Unicorn'. At least that's how I interpreted it :)

There are more Alchemical symbols shown in the NOAH logo - The Philosophers Stone. A substance or process shown to turn lead into gold and to (more importantly) give eternal life.