Methods are provided for detecting enteroviral antigens in the stomach of patients having symptoms consistent with chronic fatigue syndrome. The root portion comprises inner and outer rings and the blade portion comprises at least one layer of composite material that is folded to form a loop. In the case where the WEC is to be lifted out of the water, the hollow member is normally submerged and full of water, and, during its lifting, water drains through the wall apertures thereby reducing the weight of the member and reducing the force required to lift it. If the temperature difference is greater than the predetermined temperature change limit, an estimate of accumulated particulate matter in the after-treatment component is calculated using a secondary soot accumulation model.