Directed against cross-bridge

Ebashi (1990) hypothesized that a gene product related to MLCK acts to directly activate cross-bridges without phosphorylation of the LC20. This proposal is consistent with reports that a protein with a sequence identical to the carboxy terminal of MLCK stabilizes filament formation of SM myosin (Parker, 1993), and that polyclonal antibodies against MLCK completely inhibited force despite elevated phosphorylation (de Lanerolle et al., 1991). No regulatory theory has been proposed to account for these findings, which imply that perhaps another protein similar to MLCK but without kinase activity may play a role in modifying SM contraction. 

In the last few years, dispersed steel fibres were successfully used in prestressed concrete bridge beams where they replaced mild steel reinforcement. As one of many examples, in Figure 14.1 the cross-section of the bridge deck for Saint-Pierre-la-Cour (France) is shown. Ten prestressed concrete beams form the main structure of the bridge deck. Additional plates are used as the lost shuttering for ordinary concrete cast in situ with ordinary reinforcement and covered with road pavement. The prestressed beams and plates are made with Ductal. Thanks to 3% volume of dispersed steel microfibres in Ductal matrix, there were neither stirrups nor other mild steel reinforcement needed against shearing and local stresses in the beams and considerable economy was obtained in time and the cost of labour. This is certainly a new and important direction for the future application of fibres in structural elements without any other reinforcement. 

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