An assembly structure of a cooling air supplying duct for use in a refrigerator having cantilever shelves includes a shelf supporting rail having a front wall in which a plurality of engagement slots are formed, and a cooling air discharging duct. Various types of liquid droplet targets include metallic solutions, and nano-sized particles in solutions having a melting temperature lower than the melting temperature of some or all of the constituent metals, used a laser point source target droplets. The support area receives a patient and is defined by a head end, a foot end, a first side and a second side. The server renews the registrations for the first and second client applications in response to the given registration request message.