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Why are soft collagenous tissues so tough?

Bovine pericardium is the tissue of choice for replacing heart valves of human patients in minimally invasive surgery. The tissue has an extraordinarily high toughness of ~100 kilojoules per square meter. Here, we investigate the origin of the toughness through mechanical tests and microscopic observations. In the tissue, crimped, long, strong collagen fibers are embedded in a soft matrix. As a crack grows in the matrix, the fibers decrimp, reorient, slip, and bridge the crack. These microscopic...
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General

Managing the Giant: A Novel Approach in Orthotopic Heart Transplantation With Extreme Left Atrial Enlargement

This case report highlights an innovative surgical approach in orthotopic heart transplantation (OHT) for a patient with the largest recorded giant left atrium, measuring a biplanar volume of 1906 mL. The patient, a 63-year-old man with severe heart failure and a history of mitral and aortic valve replacements, presented with atrial fibrillation, moderate systolic dysfunction, and severe cardiomegaly. Despite optimized medical therapy, his condition warranted heart transplantation. The procedure...
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