The phrase "as first expressed" is correct and usable in written English.
It can be used to refer back to an initial statement or idea that was previously mentioned.
Example: "The concept of sustainability, as first expressed in the 1980s, has evolved significantly over the years."
Alternatives: "as initially stated" or "as originally articulated".
For book 1 of his epic poem Paradise Lost, published in 1667, John Milton invented Pandemonium – from the Greek pan (all), and daimon (evil spirit), literally "a place for all the demons" – or, as Milton first expressed in the poem: "A solemn Councel forthwith to be held At Pandæmonium, the high Capital Of Satan and his Peers".
This situation seems to be restricted to the dorsal bud as, later, nkx6.1 is first expressed during the formation of the ventral bud and ascl1b is then detected in endocrine committed cells.
Over the weekend, an Iraqi tribal sheik acting as an intermediary first expressed optimism about release of the men -- three Indians, three Kenyans and an Egyptian.
Doubts about the story surfaced almost immediately after it was published, as US officials first expressed bafflement and then denied any such lab had been found.
Her volume American Primitive (1983), which won a Pulitzer Prize, glorifies the natural world, reflecting the American fascination with the ideal of the pastoral life as it was first expressed by Henry David Thoreau.
The epitope-tagged ubiquitin is first expressed as early as the morula stage in embryonic development, without any effect on viability.
GABAergic markers such as Gad67, Calb1, and Calb2 were retained, as were SCN markers first expressed prior to induction of circadian neuropeptides during development, such as Vipr2, Id4, Arx, Dlx2, Nr1d1, and Rorb.
All amiRNAs were designed to be first expressed as pri-miRNAs from the (nonviral) miRNA expression vector pcDNA6.2-GW/EmGFP-miR.
Effect estimates for each exposure frequency category were first expressed as geometric mean ratios, with unexposed participants as the reference group, and then converted into average percent changes.
The problem is first expressed as an optimal control problem.
