The phrase "a second expression" is correct and usable in written English.
It can be used when referring to an additional or alternative way of expressing something after the first expression has been mentioned.
Example: "In addition to the first expression, I would like to introduce a second expression that conveys a similar meaning."
Alternatives: "an alternative expression" or "a different expression".
Its natural expression, though commonly used, does not respect a sharp error bound: we here first prove the correctness of a second expression.
A second expression system, in which the coding sequence was placed under control of the lambda phage PR promoter, gave 10-fold higher yields (10 mg of purified recoverin per liter of Escherichia coli culture).
On Algebraic Equivalence trials, the presentation of the initial algebraic expression was followed after 3000 ms by the appearance of a second expression, separated from the first expression by an equals sign (Fig. 1c).
The EcoRV-NotI fragment was then inserted under the cytomegalovirus promoter into the vector pTrackCMV that contains a second expression cassette for GFP dependant on CMV promoter.
To test this hypothesis, a second expression cassette, pCMV-IgKE2-23, was constructed as a control.
The construction pSI105-Tp1 also carries a second expression cassette driven by the same two constitutive promoters and terminator region.
Sometimes, a neutral expression is considered as a seventh expression.
Using (14) in the first term of (9) yields a first expression.
First, we treat the elements of the weighted channel matrix H as a constant value (block‐fading) to derive a first expression.
Control cultures also showed a first expression peak of MEF2D after 72 hours of differentiation as previously described and the expected continuous up-regulation of the more mature differentiation marker nicotinic, cholinergic receptor (Figure S5D and S5E) [39].
A third expression vector contained both the shERα_1103 and shERα_1395 expression cassettes in series (shERα_tandem).
