Umeokoli, Blessing O. [P:(DE-HGF)0] ; Onyegbule, Felix A. [P:(DE-HGF)0] ; Okoye, Festus B. C. [P:(DE-HGF)0] ; Wang, Hao [P:(DE-HGF)0] ; Kalscheuer, Rainer [P:(DE-HGF)0] ; Müller, Werner E. G. [P:(DE-HGF)0] ; Hartmann, Rudolf [P:(DE-Juel1)132001] ; Liu, Zhen [P:(DE-HGF)0] ; Proksch, Peter [P:(DE-HGF)0]