The elimination of the brackets which enclose the numerical range in Claim 1 is necessary, because the numerical range given is an essential feature of the invention and the brackets should be used only for reference signs to increase intelligibility with Figures in the sense of Rule 29(7) EPC.
Even if one skilled in the art has the reference of penis et al. and other references at the same time, they would not have conceived nor been led to the essential feature of technical theory being a base of the presently claimed invention. Namely, even if all the references are cited in front of them, collective thinking of these references would not have reached the presently claimed invention.