( ( This number ) ( ( ( ( increased parallel ) ( to ( a decrease ) ) ) ( in ( concentrations ( of ( the ( test substance ) ) ) ) ) ) . ) )
(ROOT (S (NP (DT This) (NN number)) (VP (VBD increased) (NP (NN parallel)) (PP (TO to) (NP (DT a) (NN decrease))) (PP (IN in) (NP (NP (NNS concentrations)) (PP (IN of) (NP (DT the) (NN test) (NN substance)))))) (. .)))
This number increased parallel to a decrease in concentrations of the test substance.
(ROOT (S (NP (NP (DT The) (NN number)) (PP (IN of) (NP (NP (NNS particles)) (PP (IN of) (NP (NP (DT a) (NN substance)) (PP (IN in) (NP (DT a) (VBN given) (NN volume)))))))) (VP (VBZ is) (VP (VBN known) (PP (IN as) (NP (DT the) (NN concentration))))) (. .)))