PlaidCloud expressions and filters provide use of most non-administrative PostGIS methods. PostGIS methods are accessed by prefixing the standard method name with
ST_TransScale(geometry geomA, float deltaX, float deltaY, float XFactor, float YFactor);
func.ST_TransScale(geometry geomA, float deltaX, float deltaY, float XFactor, float YFactor)
PostGIS Official Documentation for this method can be found here.
Additional capabilities and usage examples can be found in the PostGIS documentation