what i know is that "increase" is a noun and a verb at the same time , but the stress of each differs.
i.e, u can say "Nicotine increase in cigarettes" but u have to stress the first syllable "in" to make it a noun , otherwise , when u stress the second syllable"crease" ,it would be a verb; and the sentnce will be translated(after the add of (S) "يزداد النيكوتين في السجائر"
yet, there's still a slight difference in meaning between "Nicotine increase in cigarettes" and "Nicotine Increasing in Cigarettes " which is:
in the first: "increase" is a rise in amount .
in the second: "increasing" means (on the increase) for example, _Crime is on the increase_ ارتكاب الجرائم في زيادة i.e, still in process.
that's why we can't say _as i guess_ "increasing in smoking nicotine yield" becuase:
1- the yield has increased ,and that's what matters , we know it's still in the present without adding "ing" to "increase" because the results r still there.
2- we can't put "ing" coz the yield is not increasing every moment.
i hope i made it clear enough.
however , that's what i believe and i think i'm 95% right
;P