Figure 4

Journal-Concept Co-Occurrence Map for the Cardiac Literature in 2009. The network map was prepared as described for Figure 3. Clinical observation journals and concepts dominate the top half of the map. Distinct clusters can be seen for stroke on the left, surgery and electrophysiology on the top, and myocardial infarction, heart failure, and treatments (e.g., angioplasty) on the right. A small cluster of terms from molecular biology (e.g., protein kinase, nuclear factor kappa, tumor necrosis factor) exists at the bottom, linked to Circulation Research, American Journal of Physiology - Heart, and Atherosclerosis, Thrombosis, and Vascular Biology. No clearly structured translational interface exists. Circulation, however, the sole clinical mix journal in the set, maintains links to both the clinical domain and the molecular biology domain. This journal plays a key role linking diverse research interests.