In my experiments with aqueous suspensions of soy phosphatidylcholine, two DSC transition peaks were observed. First is thought to be the pretransition form gel to ripple phase and the second, the main transition from ripple to the liquid crystalline L-alpha phase. With addition of more than 10 mol% of a sterol, the first peak disappeared. Some literature suggest that addition of a sterol converts the gel phase into long ripple phase at room temperature, which is why, the first peak vanishes. But SAXS measurement of most of my samples did not give any evidence of such a phase (which must be obtained as satellite peaks of low intensity). Further, with addition of more sterol, the bilayer repeat distance, d decreases. Therefore, I suspect the sample contains liquid ordered Lo phase. But I didn't find any reference mentioning a thermal transition from Lo to L- alpha phase. Based on the geometry of the two phases, such transition seems likely. Is this transition really impossible?