Spider mechanical design

Gosline.J., Guerette, P., Ortlepp, C., and Savage, K. (1999a). Molecular and mechanical design of spider s silks. Comp. Biochem. Physiol. A Mol. Integr. Physiol. 124, S34. 

Gosline, J. M., Guerette, P. A., Ortlepp, G. S., and Savage, K. N. (1999b). The mechanical design of spider silks From fibroin sequence to mechanical function./. Exp. Biol. 202, 3295-3303. 

Plastic tube and tubular films are formed continuously by extruding a polymer through an annular die. The annular flow channel is formed by the outer die body and the die mandrel. A number of annular die designs are currently employed. In the first, the mandrel is supported mechanically onto the outer die body by a number of fins called spider legs Fig. 12.41 illustrates this type of die. The flow is axisymmetric, and the only serious problem encountered in the cross-machine direction uniformity of the extruded product is that of weld lines and streaks caused by the presence of the spider legs, which split the flow. 

I. Mechanism of toxicity. Spiders use their hollow fangs (chelicerae) to inject their venoms, which contain various protein and polypeptide toxins that are poorly characterized but appear to be designed to induce rapid paralysis of the insect victim and to aid in digestion. 

Spider silks deserve additional commentary. Again, this example shows as that Nature never gives up to complexity, as if complexity were an intrinsic part of natural materials, and this is so even in these apparently simple materials that Nature has designed just to reach a given mechanical performance. Spider silks show a highly efficient self-healing behavior that is now under intense scrutiny due to its evident technological potential [25]. 

We have designed and synthesized a series of T-shaped reversible potassium channel pore blockers. These small molecules are proposed to occlude the potassium channel pore by the insertion of an ammonium terminated ligand. This mechanism of action is well precedented in the potassium channel blocking mechanism of the natural toxin peptides isolated from snakes, spiders, and scorpions. Further evidence of the binding hypothesis will be discussed. 

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