The present study investigates experimentally the behavior of concrete confined with fiber reinforced polymers (FRP) in the form of jackets which are applied according to a number of nonconventional techniques. First, the effectiveness of various jacketing configurations combined with anchors as a measure of increasing the strength and deformability of L-shaped columns is investigated. It is concluded that easy to install and low-cost anchors made of resin impregnated fibers properly placed at the reentrant corner of L-shaped columns enable excellent mobilization of confining stresses supplied by the FRP jackets. Next, a number of alternative confinement methods are investigated on concrete cylinders, aimed at quantifying the effectiveness of (1) unbonded jacketing, (2) spirally applied strips attached only at their ends, and (3) jacketing directly on concrete with mortar plastering. Although the study may be regarded as preliminary, it provides useful experimental support to a number of techniques which ...

Terminal deoxynucleotidyltransferase (TdT) catalyzes the addition of nucleotides to 3′-hydroxyl ends of DNA strands in a template-independent manner and has been shown to add N-regions to gene segment junctions during V(D)J recombination. TdT is highly conserved in all vertebrate species, with a second isoform, characterized by a 20-amino acid insertion near the COOH-terminal end, described only in the mouse. The two murine isoforms differ in their subcellular localization, and the long isoform (TdTL) has previously been found to be unable to add N-regions. Using purified protein produced in a high level expression system in Escherichia coli, we were able to carry out detailed catalytic comparisons of these two TdT isoforms. We discovered that TdTL exhibits terminal transferase activity with kinetic parameters similar to those of the conserved TdT isoform (TdTS). We observed, however, that TdTL is inactivated at physiologic temperature but stable at lower temperatures. This thermal sensitivity of TdTL polymerase activity is not correlated with a significant change in the circular dichroism spectrum of the protein. Thus, the 20-amino acid insertion in TdTL does not affect the catalytic activity but modifies the thermosensitivity.