The application of the theory of reaction rates to the fracture of solids is reviewed. Four different models are compared and shown to exhibit three basic differences in formulation. The evidence appears to favor bond rupture, as opposed to bond slippage, as the basic mechanism leading to fracture of certain polymer systems. It is shown that other differences in the models cannot be resolved by a comparison with existing experimental data.
Peripheral gangrene caused by the extreme vaso-constriction that accompanies severe circulatory failure in such a disease as cholera is well recognized. Its occurrence, however, as a complication of myocardial infarction is such an uncommon event, to judge from the literature, that the reporting of two cases seems to be justified. On admission he was severely dyspnoeic at rest. There was no cedema. He was pale and it was noted that the end of his nose was blue and cold. The pulse was impalpable at the wrist and the blood pressure was 80/60. The apex rate was 100 a minute and the rhythm was regular. The heart showed no clinical enlargement and the heart sounds were normal. There was no pericardial friction. There were loud moist sounds all over both lungs, especially towards the bases. The liver was not enlarged.He remained seriously ill with a heart rate of around 110 a minute until December 30th, when he seemed to be a little better, but it was found that the right foot had become cold and blue up to the level of the ankle, and was anmsthetic over the same area. No pulse could be felt at the ankle, though the femoral pulses were present on both sides. On this day also it was noted that the whole of the nose was blue, livid, cold and anesthetic, and that there was a clear line of demarcation with the normal skin at the base of the nose. The tips of the ears and the tongue were unaffected, but there were some blotchy blue areas on the hands. The fingers were unaffected. Anti-coagulant treatment was started on this day.On December 31st, the left foot became affected in exactly the same way, and the right foot remained blue, cold and anesthetic. The prothrombin time was 36 seconds and a normal control was 25 seconds.He remained gravely ill, and on January 3, 1949, a blood pressure reading of 60 mm. systolic with no diastolic end point was made: he died on this day. Electrocardiograms on the fourth and tenth day of the illness showed evidence of extensive myocardial infarction (Fig. 1).Necropsy. There was gangrene of the nose with a well-defined line of demarcation, and small bulli over the healthy skin at the junction. Both feet showed gangrene, with the skin black, swollen, and wrinkled (Fig. 2). The fingers and ears did not show gangrene.
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