The January 2012 issue of Nature Materials reports on the expanding number of graphene-related patents. Entitled Exploiting the Carbon Flatland the article describes differences between universities' patenting activities and discusses the strength of university-industry collaborations in both the United States and South Korea. A table of the "Top 10 ranking of university-related inventors" puts Professors Ilhan Aksay and Robert Prud'homme of the Chemical and Biological Engineering department at Princeton University at numbers 4 and 8, respectively, in the number of patents filed. Dr. John Lettow of Vorbeck Materials is listed as tied for 10th place with researchers at the University of Texas. Vorbeck Materials has long been associated with Princeton, using licensed technologies developed at the University in the production of graphene.