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Record W4239696157 · doi:10.22215/etd/2021-14339

Biotransformation of 8:2 Monosubstituted Polyfluoroalkyl Phosphate in Rat & Human Liver, Intestine, and Fecal in Vitro Suspensions

2021· dissertation· en· W4239696157 on OpenAlexaff
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Bibliographic record

Venuenot available
Typedissertation
Languageen
FieldEnvironmental Science
TopicPer- and polyfluoroalkyl substances research
Canadian institutionsCarleton University
Fundersnot available
KeywordsBiotransformationChemistryHydrolysisPhosphateMetabolismBiochemistryBioaccumulationEnzymeEnvironmental chemistry

Abstract

fetched live from OpenAlex

Polyfluoroalkyl phosphate esters (PAPs) have been used in many commercial and industrial applications due to their grease and water repellency, and surfactant properties.However, these compounds yield transformation products such as fluorotelomer alcohols (FTOHs) and perfluorinated carboxylic acids (PFCAs) that are environmentally persistent, bioaccumulative, and potentially toxic.Given that PAPs metabolize to bioactive products, it is important to understand the sites and kinetics of this metabolism.This research compares the biotransformation of a representative PAP, the 8:2 monosubstituted polyfluoroalkyl phosphate (8:2 monoPAP) in typical host biotransformation sites, the liver and intestine, to the mammalian microbiome.The 8:2 monoPAP was incubated in human and rat (male Sprague-Dawley) liver and intestine S9 fractions, and its immediate hydrolysis products, 8:2 fluorotelomer alcohol (8:2 FTOH) was monitored by GC-MS.Human and rat fecal samples were also collected, used as a surrogate for the gastrointestinal microbiome.Enzyme hydrolysis kinetics were measured and compared.Results show that the rat and human gut phosphatases have 2-fold and 1.3-fold more affinity for 8:2 monoPAP transformation, respectively (KM (rat) = (1.2 ± 0.3) ×10 3 nM; KM (human) = (1.6 ± 0.4) ×10 3 nM) compared to liver (KM (rat) = (4.0 ± 1.5) ×10 3 nM; KM (human) = (4.9± 3.3) ×10 3 nM).Results also show the microbiome contributes to 8:2 monoPAP hydrolysis.While the liver and intestine are the primary sites for metabolism, the microbiome plays a role and should not be overlooked.This may impact the relative risk of PAP exposure, given that levels of bioactive products, including PFCAs, may fluctuate depending on environmental and genetic factors leading to microbial diversity across individuals.

Fetched live from OpenAlex and de-inverted. Abstracts are not stored in this database: the inverted indexes are 8.6 GB of the frame’s 9.3 GB of text, and the host has 13 GB free.

How this classification was reachedexpand

Full frame machine prediction

Teacher imitation

Not calibrated prevalence, not ground truth. Human validation pending. The Gemma side is a direct model label for every work in the frame, read from the title-only record. The Codex side is a classifier learned from the 10,348 direct Codex labels and calibrated to design-weighted sample rates; fields without enough sample support carry no Codex call. Candidate is the union of the two sides; consensus is their intersection. These outputs are machine_predicted_unvalidated and are not human labels.

metaresearch head score (Codex)0.000
metaresearch head score (Gemma)0.000
Version: metacan-v3-hybrid-931329e0061cValidation status: machine_predicted_unvalidated
Candidate categoriesnone
Consensus categoriesnone
DomainCandidate signal: none · Consensus signal: none
Study designCandidate signal: Bench or experimental · Consensus signal: Bench or experimental
GenreCandidate signal: Empirical · Consensus signal: Empirical
Teacher disagreement score0.005
Threshold uncertainty score0.009

Distilled classifier scores by category (both heads)

CategoryCodexGemma
Metaresearch0.0000.000
Meta-epidemiology (narrow)0.0000.000
Meta-epidemiology (broad)0.0000.000
Bibliometrics0.0000.000
Science and technology studies0.0000.000
Scholarly communication0.0000.000
Open science0.0000.000
Research integrity0.0000.000
Insufficient payload (model declined to judge)0.0010.000

Machine scores (provisional)

The two teacher heads of the student model, read on this work. A score orders the frame for review; it never asserts a category, and the validation status ships verbatim with every row.

Baseline scores from an immature model (maturity gate not passed, 7 training rounds). Scores rank; they never assert a category.

Opus teacher head0.020
GPT teacher head0.289
Teacher spread0.269 · how far apart the two teachers sit on this one work
Validation statusscore_only:v0-immature-baseline · verbatim from the scoring run: score_only means the number may rank works, and no category label ships from it

Classification

machine, unvalidated

Machine predicted; a candidate call from one source (direct Gemma or distilled Codex), not a consensus.

The models applied no category: nothing in the taxonomy fit this work.
Study designBench or experimental
Domainnot available
GenreEmpirical

How this classification was reached, model by model and score by score, is at the end of the page under "How this classification was reached".

Quick stats

Citations0
Published2021
Admission routes1
Has abstractyes

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