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Table 1 Contingency table analysis of particle numbers in different cell types among the particle sizes

From: Translocation of particles and inflammatory responses after exposure to fine particles and nanoparticles in an epithelial airway model

Cell type Pobs(Pexp) 1 μm Pobs(Pexp) 0.078 μm Row total Chi2
AM 190 (216.7) 176.67 (149.97) 366.67 3.29; 4.75
Epithelial cells 14.69 (11.3) 4.43 (7.82) 19.12 1.017; 1.47
DC 116.22 (92.9) 41 (64.31) 157.22 5.85; 8.45
Column total 320.91 (320.91) 222.1 (222.1) 543.01 24.827
  1. In the first column, the different cell types, i.e. MDM, epithelial cells, or MDDC, are denoted. In each of the cell types, the mean number of particles was counted (Pobs). According to the equation given in the methods section the number of expected particles was calculated (Pexp). To see whether the distribution of counted particles within the three cell types was different for the different particle sizes, partial chi2 values and total chi2 were calculated. For 2 degrees of freedom (3-1 cell types x 2-1 particle sizes) and with a total chi-squared value of 24.827 the null-hypothesis that the differently sized particles are similarly distributed among the different cells has to be rejected (p < 0.01). Those cell types and particle sizes that make a substantial contribution to the total chi-squared (more than 10%) are highlighted in bold letters within the table.