The phrase "an exogenous reference" is correct and usable in written English.
It can be used in contexts related to economics, social sciences, or any field where external factors influence a system or model.
Example: "In our analysis, we must consider an exogenous reference to understand the impact of external variables on our results."
Alternatives: "an external reference" or "a foreign reference".
The reactions were spiked with aequorin mRNA (0.5 μl/ 20 rxn) from jellyfish as an exogenous reference.
The transcripts were quantified and normalized to the quantity of an exogenous reference (luciferase), and reported as fold change differences relative to the immature oocyte transcript abundance.
(2) The externally defined secondary laser modulation frequency is directly encoded in the collected fluorescence, and therefore, SAFIRe does not need an exogenous reference signal for cross-correlation, but instead a lock-in amplifier or digital signal processing can be directly utilized without sacrificing signal.
By employing an exogenous reference ligand to each mixture sample, this new method utilizes the basic steps shown in Figure 1, and is distinctively characterized by the preparation of a processed-mixture-for-screening (PMFS) with the mixture sample and the reference ligand.
Each PMFS was made by mixing a mixture sample at an indicated quantity with its exogenous reference ligand (BMPL or BPDEDA) at a fixed quantity, both in methanol, to have a final reference ligand at 200 μM in each PMFS.
BPDEDA was used as the exogenous reference ligand for multiple candidate biotin derivatives in each mixture sample.
The provided control RNA Spike-in (Exiqon) was used as exogenous reference to examine the miRNAs expression profile during development and across temperatures, using the ΔΔCT method, according to Fernandes et al. [ 64].
An exogenous internal reference RNA consisting of 5×107 copies of Tobacco Mosaic Virus (TMV) was introduced into each sample during total RNA preparation.
Since the cores were collected independently of our studies of aDNA, they were not coated with an exogenous DNA tracer (as per reference [ 43]).
In our methods, to solve this technical problem, we decided to put a reference control, an exogenous spike-in with VIC probe, which allows an accurate miRNA copy number quantification and also to have control of the whole process.
Four self-probing primer reaction systems were developed to target a maize endogenous reference gene (HMG), a soybean endogenous reference gene (Lectin), a rapeseed endogenous reference gene (CruA) and an exogenous gene 5-enolpyruvylshikimate-3-phosphate synthase (ctp2-cp4epsps).
