Project Summary/Abstract We propose to continue development and support for the free and open source UltraScan-III (US3) software suite and develop new code and methods to address challenging biomedical research questions that can be solved with the latest instruments available for analytical ultracentrifugation and at beamlines for small-angle X-ray and neutron scattering experiments (SAXS/SANS) experiments. UltraScan is a comprehensive toolkit for the analysis of data from hydrodynamic experiments and simulations. Such experiments include analytical ultracentrifugation and solution bio-SAXS/SANS, as well as bead modeling simulations. Support for this project will assure continued availability of a mature multi-platform analysis suite with important and unique capabilities not found in any other software packages. Chief among them are tight integration of supercomputing capabilities, LIMS support for collaboration, and specialized analysis routines. US3 enjoys world-wide use in the AUC and SAXS/SANS communities, and offers the most robust optimization and simulation algorithms available, resulting in unmatched detail. UltraScan provides the highest throughput, a flexible, modern GUI, and a comprehensive list of analysis routines. Proposed new developments include improved automation for data acquisition, analysis, and reporting workflows, and new tools to support electronic signatures and audit trails to satisfy 21 CFR Part 11 requirements. These developments will increase the reliability and rigor of UltraScan analysis, and improve safety for patients by assuring reproducibility of therapeutic drug characterization by AUC.