The phrase "a major effect in" is correct and usable in written English.
It can be used when discussing the significant impact or influence of something within a specific context or area.
Example: "The new policy had a major effect in improving employee morale across the organization."
Alternatives: "a significant impact on" or "a substantial influence in".
Drugs that interfere with H.I.V. have had a major effect in reducing death and disability from AIDS.
Dr. Petersen, who spoke in a telephone news conference, said state and local mosquito control measures had most likely prevented many cases and would have "a major effect in blunting this epidemic".
And in a recent survey by Quinnipiac University, pollsters concluded that Mr. Casey's stand was not — at least so far — having a major effect in either the Democratic primary or the general election.
Both concrete compressive strength and web reinforcement had a major effect in controlling the shear capacity of the beams tested.
While higher flow rate was shown to have a major effect in reducing time on lag phases in both types of beads (Figures 2, 3).
In contrast to statins, the inhibition of SS results in selective cholesterol downregulation without exerting a major effect in the isoprenylation of proteins [82].
This selection can be difficult, as there are different ways to rank all the drivers that could have a major effect, but in the end two should come out on top.
These data indicate that increasing ROS in vitro has a major effect not only in limiting T-cell survival but also in reducing T-cell function.
A major effect of astrocytes in a lesion environment is through expression of extracellular matrix molecules.
Persistency is a complex trait, and both biotic and abiotic stresses are known to have a major effect on longevity in the field [ 2].
We therefore conclude that the acceleration of HSC ageing because of continuous replicative stress is a major effect of irradiation in murine leukaemogenesis.
