The phrase "a marked extension" is correct and usable in written English.
It can be used to describe a significant or noticeable increase or expansion in a particular context.
Example: "The recent research shows a marked extension of the species' habitat due to climate change."
Alternatives: "a significant increase" or "a notable expansion."
Upon addition of neuronal differentiation medium, sh-K ReNcell VM cells showed prominent neuronal differentiation starting at day 9 12, with a marked neurite extension.
Additionally dystrophic mineralization in the necrotic areas, with moderate to marked extension were observed in 15 animals.
Indeed, 95% of coral cores show a marked reduction in extension rates that persists for two years or more following the 1998 event (Fig. 3, Table 1).
Habitat suitability maps produced for three dates in the last three decades show that there has been a marked decrease in habitat extension and in connectivity to neighbouring regions.
If the initial size of a cdc2-33 fission yeast cell was smaller than 12 μm, a marked negative relationship was observed between the extension length and the initial size.
(b) Active CUL1CTD RBX1 conformation formed by a marked rotation of the RBX1 RING domain through extension of the flexible linker between the N-terminal CUL1-binding domain and the C-terminal RING region3.
The extension handle for the pneumatic nail gun had a marked decrease in the average spine compression (73%) and also had mixed effects on the productivity depending on the characteristics of the support structures under the subflooring.
Surprisingly, only a modest extension of ischemic time to 90 minutes produced a marked increase in muscle injury following reperfusion.
It is a marked change from a year ago.
We observe a marked increase in the identity and the proportion of the read aligned when employing equivalent mismatch, gap introduction, and gap extension penalties.
