Migration of human spermatozoa in an ascending temperature gradient.

<p><b>A:</b> Schematic illustration of the Lucite tube composed of two compartments for the separation process <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0041915#pone.0041915-Bahat3" target="_blank">[5]</a>. Thermocouples at both ends of the tube holder measured the temperatures at these locations. The two compartments were separated by a thin disc (316 stainless steel) having pores, 40 µm in diameter. <b>B:</b> Migration at various temperatures. The results are the mean ± SEM of 6–19 determinations (3–4 experiments for each temperature gradient tested). The temperatures shown in the abscissa were those measured by the thermocouples at both ends of the tube (externally to the tube). Asterisks above the columns indicate a statistically significant difference from the respective no-gradient control (<i>P</i>≤0.02, according to Student’s <i>t</i>-test).