Influence of a knot on the strength of a polymer strand

Article Abstract:

Experiments to determine the relative strengths of different knots show that a break in a knotted rope mostly occurs at a point just before the entrance to the knot. Knot theory, applied to the topology of macromolecules, suggests that a simple trefoil knot is usually present in long polymer strands. The effect of the trefoil knot on the breaking strength of a polymer strand is investigated using ab initio computational methods. The knot was found to significantly weaken the strand, which broke under tension at the entrance to the knot.

Macromolecules, Knot theory

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First protozoa-trapping plant found

Article Abstract:

A plant that traps and digests protozoa has been found. Genlisea, which occurs mainly in nutrient-poor areas of South America and tropical Africa, has been shown to attract protozoa with its root-like subterranean leaves and analysis of the plant reveals the presence of acid phosphatases and esterases, suggesting that ciliates are digested. The species can therefore be seen as a sophisticated and specialized protozoan trap.

Food and nutrition, Plants, Plant nutrition, Carnivorous plants

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