FIGURE 1.

Cross-sectional view of the home-built OCD cell, developed to measure peptide alignment in lipid bilayers at constant temperature and humidity. Two circular reservoirs contain the thermostated water and the salt solution used to adjust the relative humidity in the central sample chamber. The cell is mounted on a rotation stage in the sample compartment of the CD spectropolarimeter and can be rotated around the cylindrical axis, which is coincident with the optical path of the polarized light.