1. Department
of Civil and Environmental Engineering, Imperial College London, South Kensington
Campus, London SW7 2AZ, U.K.
2. School
of Civil Engineering, University of Leeds, Leeds LS2 9JT, U.K.
3. Department
of Mineralogy, The Natural
History Museum, Cromwell Road, London SW7 5BD, U.K.
4. Institute
of Biomaterials, Department of Materials Science and Engineering, University of Erlangen-Nuremberg, Cauerstr. 6 91058, Erlangen, Germany