Various embodiments are described for performing pattern matching for content based switching. For example, methods of treating gastrointestinal spasms are provided, such methods not requiring the use of systemic drugs that have shown to provide slow relief, cause adverse side effects, limit activities, worsen existing gastrointestinal conditions, be unrecommended in several gastrointestinal conditions that include gastrointestinal spasms, or be unrecommended in the absence of diarrhea. The cascade hot water heater may include a capacity variable compressor to limit a maximum flowing amount of the second refrigerant and increase a flowing amount of the first refrigerant to flow to the indoor unit. At least one vent communicates with the top wall and the protrudent column and rest of the vents surround the protrudent column. In this embodiment, the phosphorous is bonded with the substrate material in a phosphorous-oxygen-phosphorous network. The cMUT system configurations allow separate optimization for transmission and reception and better flexibility in operation.