In some embodiments, a method of allowing navigation of a plurality of data elements residing within a category-tree database includes providing, on a single primary \u201cweb\u201d page, a distinct data element symbol for each data element and a distinct parent category symbol for each parent category in the category paths of the data elements. Associated apparatus is disclosed. First electrode sets are disposed on the first inner wall, and second electrode sets aligned with the first electrodes sets are disposed on the second inner wall. Users accessing the portal site are presented with options in a menu or other convenient format identifying the tools and services available, and are able to more rapidly complete circuit designs by having access to a wide variety of tools and services in a single locale. A device embodying features of the invention can include a sealing member at a location on a shaft of the device proximal to a treatment location therein to seal the passageway leading to the body cavity.