Nuclei concentration.

<p>Calculated profiles of nuclei concentrations (pM) versus length (nm), or equivalently time scale, as a function of the bin size. 2 monomers/bin corresponds to 0.47 nm/bin, while 20 monomers/bin corresponds to 4.7 nm/bin.</p

Equations and variables.

<p>Set of equations used to estimate the total number of insulin nuclei, <i>N_n,t</i>, from the available fibril length distribution. The number of measured fibrils per i-th bin, <i>N_fi</i>, Eqs. (1) & (3), were calculated using the Weibull distribution (<a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0020072#pone-0020072-g001" target="_blank"><b>Figure 1</b></a>). From the definition of the nucleus, the total number of fibrils, <i>N_f,t</i>, is equivalent to the total number of nuclei, <i>N_n,t</i>, Eq. (4). A description and the units are provided for each variable.</p

Fibril length distribution.

<p>The histogram of frequency versus fibril length summarizes AFM data for 495 insulin fibrils in 36.6 nm/bin for a total of 100 bins. The parameters of this distribution were estimated using distribution-fitting software, EasyFit (MathWave Technologies). The software fitted the data using 60 different distributions and ranked the results based on three different goodness-of-fit tests. The histogram shows the best fit (Kolmogorov-Smirnov statistic, <i>D</i> = 0.0187, Anderson-Darling, <i>A²</i> = 0.323, and Chi-Squared, <i>χ²</i> = 5.113) using the Weibull distribution (line). The probability density function is with values of the parameters: α = 1.7409 and β = 1248.5. (A) Example of a 2D AFM image of insulin fibrils, with measurements: A free-hand curve was drawn on the fibril and two cursors placed at each fibril end. Measurements are in nm. (B) Example of a 3D image, which assisted in detecting individual fibrils.</p