Extended stretching

Extending (Stretching or Lengthening) of Gelatin-Dynamites. Under this term are known Dynamites contg less than 20-25%... 

Portions of the polypeptide chains that are not accounted for by a helix or /3 conformation consist of bends and irregularly coiled or extended stretches. Segments of a helix and j3 conformation sometimes deviate slightly from their normal dimensions and geometry. 

A salient feature of all known pores is their irreversible anchorage in the lipid bilayer (Bhakdi and Tranum-Jensen, 1987). Hence, membrane-bound PFTs must be amphiphilic, possessing a lipid binding surface and a hydrophilic face that lines the aqueous channel. The pore-forming domains themselves are unlikely to harbor extended stretches of hydrophobic amino acid residues. Rather, they would be expected to possess amphipathic secondary structure. Rules to identify or predict pore-forming sequences do not exist, and even the solution of the structure of a water-soluble protomer form will not permit conclusions to be drawn on the structure of the pore. This situation is given in the case of aerolysin (Parker et al., 1996). 

Clamping the material and carrying out a true punch action where the non-held area is extended (stretch forming). 

Although the analysis of [97] was not exhaustive, it succeeded in identifying extended conformations of minimum energy for stereoirregular model chains of PAN in which the torsion angles are close to 180° in racemo diads and may deviate significantly from 180° in meso diads. As an example, locally extended stretches of rmr tetrads and rmmr pentads in a minimum energy conformation are shown in Fig. 11. 

Extrusion stretch blow molding is a two-stage process using two mold/mandrel sets — one for pre-blow and the other for final blow. An extruded parison is first pinched off and blown conventionally in a relatively small pre-blow mold to produce a closed-end preform. The preform is then transferred to the final blow mold where an extending stretch rod within the blowing mandrel bears on the closed preform end to stretch it axially. The stretched preform is then blown to impart circumferential stretch. Standard blow molding machines can be converted for extrasion stretch blow molding. 

---