deletions | additions       diff --git a/Introduction.tex b/Introduction.tex  index 792c456..9521a41 100644  --- a/Introduction.tex  +++ b/Introduction.tex 
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R_{min} \text{(nm)} = 0.066 \cdot \text{MW}^{1/3} \label{eq:Erickson}  \end{equation}  However, proteins have a rough surface, are often not perfectly spherical, and their charge affects the diffusion of a molecule in solution. The hydrodynamic radius $R_h$, defined as the radius of a hard sphere that diffuses at the same rate as that the  solute, takes these effects into account. The hydrodynamic radius is important in predicting transretinal penetration.\cite{Jackson2003,Ambati2000a} Small-angle scattering studies using X-rays (SAXS) or neutrons (SANS) \cite{Svergun_2013} as well as dynamic light scattering (DLS) \cite{Pecora_1985,Hong_2009} and nuclear magnetic resonance (NMR) techniques \cite{Wilkins1999} have been used for measuring $R_h$. Empirical relationships have been defined between $R_h$ and the number of amino acids $N$ (related to the MW by \(N = \frac{\text{MW}}{110 \text{ Da}}\)), for example, by Wilkins \textit{et al.}\ \cite{Wilkins1999}  \begin{equation} 
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R_h^D (\text{\AA}) = 1.45\cdot(2.24\cdot N^{0.392}) = 3.248\cdot N^{0.392} \label{eq:Dill}  \end{equation}  These formulas were obtained by global analysis of hundreds of proteins, and fitting to a scatter plot of $R_h$ against MW. While these formulas they  give a good indication of the expected size, there is a big variance in the measured $R_h$ as a function of MW. This can be explained by the diversion of these models from the protein's actual shape, properties,  which is are  due to molecular shape, charge and surface roughness. %\subsection{Radius measurement from anisotropy}