James Kindt of Emory University is supported by an award from the Theoretical and Computational Chemistry program to carry out research on the development of theoretical methods for the study of molecular and mesoscale structure in mixed bilayers and bicelles. The project is partially supported by the Molecular Biophysics program within the Division of Molecular and Cellullar Biosciences. The work continues Kindt's successful efforts under a prior award with a new focus on mixtures of lipids, which are important in real cell membranes. A mixed Monte Carlo/molecular dynamics method, in which random mutation moves, is being used to simulate a thermal distribution of lipid configurations. This is expected to help overcome the problem of time scales in the system, which will be an advance over existing techniques that have not been able to run simulations long enough to watch the lipids diffuse laterally. The PI is also collaborating with an experimentalist in Bordeaux, who is carrying out NMR experiments on mixed lipid systems. The computer code which is being developed during this research will be incorporated into the popular Gromacs molecular dynamics package and made available to other researchers in the field, thus broadening the impact of the work. The PI, who has a history of including undergraduates in his research program, is continuing to do so, incorporating them into the Bordeaux collaboration by participation in an existing summer research abroad program at Emory.