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The objective of this paper is to find a sequence of jobs in the flow shop to minimize makespan. A feed forward back propagation neural network is used to solve the problem. The network is trained with the optimal sequences of completely enumerated five, six and seven jobs, ten machine problem and this trained network is then used to solve the problem with greater number of jobs. The sequence obtained using artificial neural network (ANN) is given as the initial sequence to a heuristic proposed by Suliman and also to genetic algorithm (GA) as one of the sequences of the population for further improvement. The approaches are referred as ANN-Suliman heuristic and ANN-GA heuristic respectively. Makespan of the sequences obtained by these heuristics are compared with the makespan of the sequences obtained using the heuristic proposed by Nawaz, Enscore and Ham (NEH) and Suliman Heuristic initialized with Campbell Dudek and Smith (CDS) heuristic called as CDS-Suliman approach. It is found that the ANN-GA and ANN-Suliman heuristic approaches perform better than NEH and CDS-Suliman heuristics for the problems considered.

Altered microtubule (MT) stability prior to neurite extension was examined in P19 embryonal carcinoma cells induced to differentiate along the neural pathway by retinoic acid. In undifferentiated P19 cells few acetylated MTs were detected by immunofluorescence staining and these were resistant to disassembly by colchicine at 1 $\mu$g/mL for 45 minutes. Twenty-four hours after neural induction there was an increase in the number of acetylated MTs and in the number of MTs that were resistant to colchicine treatment. This suggested that the MT array in undifferentiated cells is initially dynamic and becomes less dynamic during early neural differentiation prior to morphogenesis. Quantitative immunoblotting showed no change in the levels of total tubulin, but a two-fold increase in the relative level of acetylated tubulin was detected. MT turnover in P19 cells was then examined directly by microinjecting biotin-conjugated bovine brain tubulin. Computer-aided silicon intensified target camera (SIT) imaging of biotin-tubulin incorporation into the MT array showed that by 30 minutes, 92.4 $\pm$ 3.02% of total MTs turned over in undifferentiated cells. In contrast, in the retinoic acid-induced cells 52.8 $\pm$ 19.37% of the MT array turned over in 30 minutes. In conclusion, there are changes in colchicine stability and in tubulin acetylation that are correlated with changes in MT dynamics occurring prior to neurite outgrowth.