... 1274 THE JOURNAL OF ANTIBIOTICS ... 2H), 5.76 (d, 1H,J=4)9 6.29 (d, 1H,J=4), 7.93 (d, 1H,J=4)9 8.78 (d, 1H,J=4), 8.87 (s ... Antibiotic Susceptibility Testing Antibiotics: Cephalosporins synthesized in this program were prepared at a concentration of 2mg/ml of active material in a ...