648.70—What conditions must be met by a fellow?
         To continue to be eligible for a fellowship, a fellow must—
    
    
    
        
        (b) 
         Devote essentially full time to study or research in the academic field in which the fellowship was awarded; and
    
    
        
        (c) 
         Not engage in gainful employment, except on a part-time basis in teaching, research, or similar activities determined by the academic department to be in support of the fellow's progress toward a degree.