...city itself, though not properly a fortress, was sufficiently strong, in its encincturement of 'wall and towers and river, to be able to make a stubborn resistance.

Briefly, various concentrations of austrobailignan-1 were added to the topoisomerase-1 activity reaction mixture (including 250 ng pHOT-1 plasmid DNA, 0.3 U calf thymus DNA topoisomerase 1, 20 mM Tris-HCl, pH 8.0, 72 mM KCl, 5 mM MgCl 2, 5 mM dithiothreitol, 2 mM spermidine, 0.01% bovine serum albumin) for 30 min at 37°C, and the reaction was stopped by loading dye solution (2.5% SDS, 25 mM EDTA, pH 8.0, 15% ficoll-400, 0.05% bromophenol blue, and 0.05% xylene cyanole).

This great semicircle, for lack of a name, may be called the fertile crescent.

a brittle, spalt wood