Talk:Persistence length

I thought persistence length was defined as the length required (in solution) for the average bend angle of the molecule to be one radian... - Zephyris _Talk 12:57, 31 January 2007 (UTC)

The persistence length of the spaghetti is wrong... the article cited is wrong also. The persistence length of a spaghetto is bigger that 50 cm. —Preceding unsigned comment added by 152.3.68.8 (talk) 13:30, 12 April 2011 (UTC)

I tried to fix the persistence length of the spaghetti citing another article that is more reasonable, it say 10 cm, also if I think it's bigger. (same guy of the previous comment) —Preceding unsigned comment added by 152.3.68.8 (talk) 22:12, 20 April 2011 (UTC)

I edited AGAIN, because somebody changed it back. I added the derivation of the persistence length from the young modulus and the bending stiffness. A spaghetto have an INCREDIBLE persistence length, sound strange but it is true. Ayexeyen (talk) 23:17, 21 April 2011 (UTC)

The cited article refers to uncooked spaghetti, in which case a large persistence length is reasonable. The original comparison between DNA and spaghetti seems to relate to a Trends in Biotechnology article by Ned Seeman (http://www.cs.duke.edu/courses/cps296.4/spring04/papers/Seeman99.pdf), where he assumes 1.5 cm for cooked spaghetti. He doesn't have a reference for this and I doubt he measured it himself, so this has to be classified as an estimate. However, cooked spaghetti are a far 'better' polymer insofar as they are available in lengths comparable to or larger than their persistence length, which uncooked ones are not. Avocadohead (talk) 19:22, 27 April 2011 (UTC)

That's why I put 0.1GPa that is much lower compared to the published value of the uncooked . Value that I found here: www.sfu.ca/~boal/mocex/MoC2E.pdf I tried also to do an experiment with a cooked spaghetto (single one). In a pot full of water it's really straight. Ayexeyen (talk) 22:09, 28 April 2011 (UTC)

I have also found another source: Folding and self-assembly of biological macromolecules, authors: Westhof, E. and Hardy, N., journal Proceedings of the Deuxi{\.e}mes Entretiens de Bures and there they speak (at pag 50) about the persistence length of spaghetti. They clain that is (more than) thousands kilometers! Because the "thermal fluctuation do not matter for spaghetti". The persistence length is something related to the thermal fluctuation of the environment and it's not "how much you can bend" something. Ayexeyen (talk) 23:32, 28 April 2011 (UTC)

Persistence length and Kuhn length: The relationship 2lp=lk is only valid for a worm-like-chain. --Fanfun (talk) 12:01, 30 September 2012 (UTC)

This article is very poor and should be flagged for attention. Attempts to quantify this value (and Kuhn length) are tautological at best. — Preceding unsigned comment added by 2600:1702:3C80:DB30:B932:430D:D8A7:A0B (talk) 05:17, 2 October 2021 (UTC)