The phrase "ascertained portion" is correct and usable in written English.
It can be used in contexts where you want to refer to a specific part or segment that has been determined or identified.
Example: "After reviewing the data, we focused on the ascertained portion that showed the most significant trends."
Alternatives: "determined segment" or "identified part".
While numerous studies have highlighted the ability of humic substances (in general) to enhance plant response and growth parameters, the new challenge is to ascertain what portion or specific component(s) of the humic substances is most responsible for generating the positive response [15].
However, we could not ascertain what portion of the probes which were designed to measure the endogenous human transcripts showed this behavior because it is not possible to vary the target concentration for each of those transcripts in a controlled, quantitative manner.
The trained model was then applied to the macaque and mouse data to ascertain which portions of the Calu-3 model are consistent with the regulator-target relationships in these in vivo systems.
Information on age, sex, race/ethnicity, and smoking was ascertained from the questionnaire portion of the survey.
Before randomization, all subjects were asked to provide detailed demographic and smoking information, to give a history of physician-confirmed diseases, and to complete a 276-item dietary questionnaire that ascertained both frequency of intake and portion size.
Since YTX induces structural alterations of this portion of E-cadherin, we ascertained whether it could also affect the association of β- and γ-catenins with E-cadherin.
The dietary section of the questionnaire ascertained the frequency of consumption and usual portion size of 117 food items (including alcoholic beverages) and was used to estimate daily intake of alcohol and calories.
No interviews or estimations of portion size were required during data collection; average age-specific and sex-specific portion sizes for all foods consumed were ascertained using relevant UK National Diet and Nutrition Survey data.
Second, the association between "portion control behavior" and "body mass index" was ascertained.
