Hi,everyone.While reading the tutorial, I found some of the illustrations below：
In the Materials Studio tutorial Effects of surfactant on a lipid bilayer using DPD (Tutorials > Mesocite tutorials > Effects of Tutorials) surfactant on a lipid bilayer using DPD) mentioned:

In other words, the first term of the relationship between the exclusion parameter a and the Flory-Huggins Chi parameter χis the constant 25, but this 25 is the value when a bead represents a water molecule, but the mass of the bead chosen here represents the mass of 3 water molecules, so the value here needs to be multiplied by 3. It's about 78, As The tutorial says, "The default value in Mesocite (25) is based on the case where a bead represents one water molecule (Groot and Warren, 1997).” .

However, all the same, Another tutorial from Materials Studio, Calculating input parameters for a DPD simulation (Tutorials > Mesocite tutorials > Tutorials) Calculating input parameters for a DPD simulation), a bead has a mass of 281.4 amu, but this formula is used directly here:

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It is obvious that the mass of a bead is not equal to the mass of a water molecule, but the first term 25 has not been scaled. I do not know whether there is something wrong with my understanding or what is going on. I hope the teacher is not stingy advice, thank you very much!!