The phrase "altered by several" is correct and usable in written English.
It can be used when discussing changes made by multiple individuals or factors to something, such as a document, design, or plan.
Example: "The original manuscript was altered by several editors before publication."
Alternatives: "modified by multiple" or "changed by several".
Development can be altered by several factors which can either facilitate or obstruct development.
This layer also ensures that files which can be altered by several network users are kept in order.
And my sense of what a vehicle can provide in terms of acceleration, cabin comfort and exacting design was fundamentally altered by several days spent driving the Wraith along the coast.
It was found that, even though the PZC of the studied oxides can be altered by several pH units, modified alumina and silica exhibit the same platitum adsorption characteristics as the unmodified supports.
Gene expression can be altered by several mechanisms influencing mRNA transcription.
Processing of Nrx3β can be altered by several PS1 mutations of the γ-secretase that cause early-onset familial AD (Bot et al., 2011).
With respect to specific genes coherently altered by various dietary paradigms, there are several striking functional interactions, e.g. between two genes that conversely regulate cytokine signaling.
Interestingly, while MUC5AC was the only mucin gene significantly altered by AZT exposure, several MMPs (MMP1, 2, 10, 13, and 28) in addition to MMP9 tended to be down-regulated by AZT.
However, evolutionary pathways may be altered by humans in several ways.
These data indicate that NAT-dependent biotransformation of AAs may be altered by Cd in several tissues expressing these XMEs.
The k4 rate is relatively slower than the other rates in the model; nevertheless, the simulation's overall protein production was not altered by changes of several orders of magnitude around its value... .......... [ 41].
