a list containing:
1) datasets:a data drame providing the RPKM of seven mixing samples.
2) proportions: a data frame providing the fractions for liver and kidney in the mixing samples
3) signatures: a data frame providing the expression values from pure liver and kidney samples
A list 1) a data frame with 31979 genes' expression on the 7 mixing samples: reads.1, reads.2, reads.3, reads.4, reads.5, reads.6, reads.7
2) a martix whose rows are mixing samples' name and columns are fractions from pure live and kidney tissues
3) a data matrix with 630 expressions from pure liver and kidney tissues