1. Molecular Basis of the Apparent Near Ideality of Urea Solutions
Hironori Kokubo, Jörg Rösgen, D. Wayne Bolen, B. Montgomery Pettitt 
Biophysical Journal 
Volume 93, Issue 10, Pages (November 2007)
DOI: /biophysj
Copyright © 2007 The Biophysical Society Terms and Conditions

2. Figure 1
Typical snapshots of KBFF urea solutions. The figures correspond to the systems of mole fraction (a), (b), (c), and 1.0 (d), respectively. Only atoms within the sphere with 9.0Å radius in the center of the specific one urea molecule are drawn. Urea molecules are drawn as space-filling and water molecules are ball-and-stick. VMD was used for this figure.
Biophysical Journal  , DOI: ( /biophysj )
Copyright © 2007 The Biophysical Society Terms and Conditions

3. Figure 2
The excess chemical potential integrand components in the case of the most dilute KBFF urea solution. (a) Integration path for the calculation of vdW terms of excess chemical potential by thermodynamic integration method. Integrating this path about lambda becomes the total vdW excess chemical potential. (b) The 51 λ-points for the calculation of vdW terms of excess chemical potential by Bennett acceptance ratio method (black asterisk) and perturbation method (+, estimation Eq. 57, blue circle; –, estimation Eq. 58, red triangle). Adding the differences of 51 points becomes the total vdW excess chemical potential. Asterisk and circle overlap very well. (c) Similar to panel a for electrostatic terms. (d) Similar to panel b for electrostatic terms.
Biophysical Journal  , DOI: ( /biophysj )
Copyright © 2007 The Biophysical Society Terms and Conditions

4. Figure 3
Activity coefficients in various scales. (a) Activity coefficients in the mole fraction scale. (b) Activity coefficients in the molality scale. (c) Activity coefficients in the molarity scale. Solid square marks are for KBFF urea solution by our simulations. Solid diamond marks are for OPLS urea solution by our simulations. Multiple marks are for experimental values (12–14,35).
Biophysical Journal  , DOI: ( /biophysj )
Copyright © 2007 The Biophysical Society Terms and Conditions