c*******n
发帖数: 1648 | 1 What do you mean?
It's not F=Ma? | M*******n
发帖数: 508 | 2 yeah, it is, the question is how to determine the value of M,
as I understand in macroscopic view, it should be M(DNA)-M(Solvent).
M(solvent) = Density(solvent)* Partial Volume
what's the relationship between partial volume and hydrodynamic volume?
【在 c*******n 的大作中提到】
: What do you mean?
: It's not F=Ma?
| c*******n
发帖数: 1648 | 3 I think centrifuging used to be a popular method for determiniing of M of
macromolecules.
A lot of old papers must have covered what you want to know. I have basic
principles of this method in a Chinese version Polymer Physics book, but no
details. For dilute solution, partial volume will not be very different from
volume in pure solvent. Maybe you can use volume for pure solvent:)
【在 M*******n 的大作中提到】
: yeah, it is, the question is how to determine the value of M,
: as I understand in macroscopic view, it should be M(DNA)-M(Solvent).
: M(solvent) = Density(solvent)* Partial Volume
: what's the relationship between partial volume and hydrodynamic volume?
| s***e
发帖数: 911 | 4 我正好也需要问这问题.
DNA在良好溶液里的coil volume相当大,这coil是个十分疏松的结构. 所以水分子
能够自由进出这个coil. 于是一个DNA的排水体积就是它本身的体积,和hydrodynamic
volume(coil volume)没有关系. 以这计算的话, DNA密度比水密度大三倍. 如果以
14k g的离心加速度, 一个lambda DNA 20分钟内能沉降1cm. 我以前没考虑过这问题.
昨天作了这估算,到是把我自己吓了一跳.因为我每次实验前都spin我的样品很长
时间.
麻烦各位看看是否有理.
【在 M*******n 的大作中提到】
: yeah, it is, the question is how to determine the value of M,
: as I understand in macroscopic view, it should be M(DNA)-M(Solvent).
: M(solvent) = Density(solvent)* Partial Volume
: what's the relationship between partial volume and hydrodynamic volume?
| c*******n
发帖数: 1648 | 5 It's interesting, basically you are saying DNA follow Rouse instead Zimm? I
wish I had enough time and could discuss with you intensively and learn sth
for bio guys, but I'd better to disppear in the next two weeks. Otherwise my
boss will be angry. Besides the density, diffusion coeff. will make huge
difference on your result.
【在 s***e 的大作中提到】
: 我正好也需要问这问题.
: DNA在良好溶液里的coil volume相当大,这coil是个十分疏松的结构. 所以水分子
: 能够自由进出这个coil. 于是一个DNA的排水体积就是它本身的体积,和hydrodynamic
: volume(coil volume)没有关系. 以这计算的话, DNA密度比水密度大三倍. 如果以
: 14k g的离心加速度, 一个lambda DNA 20分钟内能沉降1cm. 我以前没考虑过这问题.
: 昨天作了这估算,到是把我自己吓了一跳.因为我每次实验前都spin我的样品很长
: 时间.
: 麻烦各位看看是否有理.
| s***e
发帖数: 911 | 6 I'll post my calculation here soon.
【在 c*******n 的大作中提到】
: It's interesting, basically you are saying DNA follow Rouse instead Zimm? I
: wish I had enough time and could discuss with you intensively and learn sth
: for bio guys, but I'd better to disppear in the next two weeks. Otherwise my
: boss will be angry. Besides the density, diffusion coeff. will make huge
: difference on your result.
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