The data file must be a .txt file with tabs or spaces as field separators.

It must be formated with one row per item (e.g. probes, metabolites),
one column per sample (e.g dose/concentration).

The first column must correspond to the identifier of each item (in a column
named "item"), and the other columns must give the responses of the item for 
each sample (i.e. each replicate at each dose or concentration). 

The names of the columns must correspond to the tested doses or concentrations
in a numeric format (for example, if there are triplicates for each treatment, 
column names can be "item", 0, 0, 0, 0.1, 0.1, 0.1, etc).