The phrase "assay for absence" is correct and usable in written English.
It can be used in contexts related to testing or examining for the lack of something, often in scientific or technical discussions.
Example: "The researchers conducted an assay for absence of contaminants in the water samples."
Alternatives: "test for absence" or "check for absence".
The extraction method comprises a combination of water and organic solvent extractions, and each final extract is assayed for absence of residual solvents.
The pair that assays for the absence of the TE consists of a Flank (FL) primer, which is located in the left flanking region of the TE and the R primer mentioned above (see in [ 38] for further details).
To examine developmentally related kinase activity, a particulate membrane fraction of pre- and postclimacteric apple fruit proteins was incubated in [γ-P]ATP in an in vitro phosphorylation assay for 30 min in the absence or presence of the ACCO fusion protein or with ACCO alone.
The RNA samples were tested for absence of inhibitors using the SPUD assay - no inhibitors were detected [36].
We obtained BMI measures for all donors, and assayed for presence or absence of cytomegalovirus and Epstein-Barr virus infection, but none of these factors were correlated with the PC axes of variation.
To verify that secreted hK1 is enzymatically active, GIST882 supernatants were assayed using a colorimetric assay for hK1 in the presence or absence of the serine protease inhibitor aprotinin and specific inhibitors VA999154 and VA999024.
To address this issue, we repeated the viability assay for HNE and ONE in the absence of serum to determine if ONE's apparent toxicity was lowered because of its higher reactivity with serum proteins, as compared to HNE.
While bearing in mind these limitations, in the current absence of an assay for autophagic flux in paraffin-embedded tissue, we nonetheless believe that the protocol we present here constitutes a useful step forward in the ability to analyze autophagy in both normal and diseased tissue from human and mouse.
The absence of a standardized, easily implementable enzyme activity/inhibition assay for Atg4B most likely contributes to this situation.
Briefly, for each TE, two primer pairs were designed: one was intended to assay for the presence of the TE, and the other was intended to assay for the absence of the TE.
