The phrase "as first observed in" is correct and usable in written English.
It can be used when referencing a source or study where a particular observation or finding was initially noted.
Example: "The phenomenon of quantum entanglement was first described in the 1935 paper by Einstein, Podolsky, and Rosen, as first observed in their groundbreaking work."
Alternatives: "as initially noted in" or "as previously reported in".
As first observed in 1891 by Seth Carlo Chandler Jr., an insurance actuary turned astronomer, the Earth's axis sways back and forth about 20 feet every 14 months.
As first observed in laboratory measurements of cyanobac-teria and other photosynthetic organisms, a large change in the value and even sign of circular polarization in our simulations occurs within the absorption band of the material.
Scientists were wondering, too, and recently performed an analysis of 2,500 recipes to find out, as first observed in the Washington Post.
This hydrogen bond network comprises the l-amino acid recognition motif, as first observed in the rat arginase I ABH complex.
This requires NSF (N-ethylmaleimide sensitive fusion protein) and SNAP (Soluble NSF Attachment Protein), as first observed in the Golgi transport in yeast (Clary et al, 1990).
Polyploidization can result in noticeable phenotypic effects, as first observed in the tetraploid " gigas" mutants of Oenothera lamackiana (DeVries 1915 and references therein).
As Carr first observed in his much discussed 2008 article in The Atlantic, "Is Google Making Us Stupid?," the mere existence of the online world has made it much harder (at least for him) to engage with difficult texts and complex ideas.
As we first observed in yeast cells [ 11], also in human cells the BRCA1 variants M1775R and A1789T affect the expression of many genes critical for cell proliferation and genome integrity maintenance.
The character of the structure where nucleation preferentially occurs is presumed to be in heavily deformed regions as nuclei were first observed in such microstructures as viewed from the specimen surface.
When the speed of a charged particle in a transparent medium (air, water, plastics) is so high that it is greater than the group velocity of light in that medium, then a part of the energy is emitted as Cherenkov radiation, first observed in 1934 by Pavel A. Cherenkov, a Soviet physicist.
The fact that retinal cells inhibit their neighbors, an activity known as "lateral inhibition," was first observed in horseshoe crabs by physiologist H. Keffer Hartline.
