Complex sentence: When exposed to 25 μM CTN for 24 h no significant decrease was found, however when incubated to higher amounts, 50 and 75 μM, the overall viability dropped to 51% and 22% of control levels respectively.
Split into simpler sentences: When exposed to 25 μM CTN for 24 hours, no significant decrease was found. However, when incubated to higher amounts, 50 and 75 μM, the overall viability dropped to 51% and 22% of control levels respectively.