By adding certain chemicals, the ROS can be measured using the emission of light of a certain wave-length.
1	By	by	SCONJ	IN	_	2	mark	2:mark	Discourse=mode-means:114->115:1
2	adding	add	VERB	VBG	VerbForm=Ger	10	advcl	10:advcl:by	_
3	certain	certain	ADJ	JJ	Degree=Pos	4	amod	4:amod	Entity=(159-substance-new-cf3-2-sgl
4	chemicals	chemical	NOUN	NNS	Number=Plur	2	obj	2:obj	Entity=159)|SpaceAfter=No
5	,	,	PUNCT	,	_	2	punct	2:punct	_
6	the	the	DET	DT	Definite=Def|PronType=Art	7	det	7:det	Discourse=context-background:115->111:2|Entity=(138-substance-giv:act-cf1*-2-coref-Reactive_oxygen_species
7	ROS	ROS	PROPN	NNPS	Abbr=Yes|Number=Plur	10	nsubj:pass	10:nsubj:pass|11:nsubj:xsubj	Entity=138)
8	can	can	AUX	MD	VerbForm=Fin	10	aux	10:aux	_
9	be	be	AUX	VB	VerbForm=Inf	10	aux:pass	10:aux:pass	_
10	measured	measure	VERB	VBN	Tense=Past|VerbForm=Part|Voice=Pass	0	root	0:root	_
11	using	use	VERB	VBG	VerbForm=Ger	10	xcomp	10:xcomp	Discourse=mode-means:116->115:0
12	the	the	DET	DT	Definite=Def|PronType=Art	13	det	13:det	Entity=(160-event-new-cf2-2-sgl
13	emission	emission	NOUN	NN	Number=Sing	11	obj	11:obj	_
14	of	of	ADP	IN	_	15	case	15:case	_
15	light	light	NOUN	NN	Number=Sing	13	nmod	13:nmod:of	Entity=(161-substance-new-cf4-1-sgl
16	of	of	ADP	IN	_	21	case	21:case	_
17	a	a	DET	DT	Definite=Ind|PronType=Art	21	det	21:det	Entity=(162-abstract-new-cf5-5-sgl
18	certain	certain	ADJ	JJ	Degree=Pos	21	amod	21:amod	_
19	wave	wave	NOUN	NN	Number=Sing	21	compound	21:compound	SpaceAfter=No|XML=<w>
20	-	-	PUNCT	HYPH	_	19	punct	19:punct	SpaceAfter=No
21	length	length	NOUN	NN	Number=Sing	15	nmod	15:nmod:of	Entity=162)161)160)|SpaceAfter=No|XML=</w>
22	.	.	PUNCT	.	_	10	punct	10:punct	_
