A derived factor is one whose levels are derived from those of another factor - either as a numerical formula, or by categorical mapping. Therefore, to define a derived factor, the factor from which levels will be derived must have been previously defined.
In Synthace, derived categorical factors often relate to the Diluent to Use parameter in both the Make Mixtures and Mix Onto elements often in conjunction with Custom Factors.
In this tutorial you will learn:
Where to add a derived categorical mixture component factor.
How to pair the levels of one categorical factor to the numerical levels of another.
Define the numerical factor to derive from
Build a workflow that defines a set of a set of Buffers (Buffer A, B, and C) in the Define Liquids and Plates element.
Add reagents (Liquid A and B) in the Define Liquids and Plates element, each with a concentration of 1M, enable Calculate Required Stocks. Add and connect the Liquid Selection Crtieria element and define a minimum transfer volume of 0.5 ul.
Switch the workflow builder into DOE Mode
Note: only the elements that can have DOE factors applied to their parameters will be interactive and display in colour. If the workflow has not already been added to a Synthace experiment you will be prompted to do so before being able to enter DOE mode.
Select the Make Mixtures element and toggle on the Mixture Compositions and Diluent To Use parameters to identify that you intend to treat these as DOE factors.
Click on a factor button in the Instance Panel to launch the DOE Factor Panel.
Add two new factors to the Make Mixtures 1 > Compositions parameter for Liquid A and Liquid B with levels that sample a range between 10 and 100 mM. For more details on how to do this, click here.
Add a new numerical factor to the Custom Factors section called pH with levels 6, 7 and 8. For more detail on how to do this, click here.
Defining the derived categorical factor
Click on the Add button next to the Make Mixtures 1 > Diluent To Use parameter, and select New Derived Factor.
Select pH in the Derive From Factor dropdown box.
Note: This indicates to Synthace that you want the levels for this factor to be derived from the numerical pH factor you have already defined in the Custom Factors section.
Specify which factor levels should be paired between the two factors, by using the input fields and dropdown menus. In this example Buffer A should be used when the pH is 6, Buffer B when the pH is 7, and Buffer C when the pH is 8.
Once all levels have been paired, click Add Factor. Synthace will show the summary details of the factor in the factor table, indicating that this factors levels are derived from another in the Type column.
Check the derivation
Click on the Calculate Design tab at the top of the Factor Table.
Note: All design factors will be included in the design diagnostic calculations. However, note that the derived categorical factor for the Diluent To Use parameter is not included. This is because its levels are derived from the pH factor, therefore the derived factor does not contribute to the actual design calculation, only the factor it is derived from is included.
Scroll to the Final Run Matrix at the bottom of the panel.
Note: The buffer chosen when the pH factor level is 6 will be Buffer A, when the pH is 7 it will be Buffer B, etc. You can validate this by looking at the factor columns in the design matrix for the pH and diluent factors. Note that all other factors are treated as normal factors in the DOE design and the level constraint is only applied to the derived factor.
Well done on making it to the end of this tutorial.
To learn about other factor types, click here.