Professor Martin Yarmush�s research in tissue engineering and metabolic engineering is highlighted as cover articles in 2 journals. The first, an article entitled, "Oxygen Uptake Rates and Liver-Specific Functions of Hepatocyte and Fibroblast Co-Cultures", appears on the cover of the May 1 issue of Biotechnology and Bioengineering. The second, an article entitled, "Integrated Energy and Flux Balance Based Multiobjective Framework for Large-Scale Metabolic Networks", will appear on the cover of June 2007 Special Issue of the Annals of Biomedical Engineering on "Systems Biology and Bionformatics".