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Tag: Valuation & Resource Economics

  • Perfluorohexyloctane altered human hepatocyte metabolism

    What the study found

    Perfluorohexyloctane (F6H8) caused broad metabolic reprogramming in human HepaRG hepatocytes, which are human liver cells used in research. The study also detected a putative biotransformation product, perfluorohexyloctanoic acid, suggesting that F6H8 may be metabolically persistent.

    Why the authors say this matters

    The authors conclude that F6H8 may not be metabolically inert as previously assumed. They also say the findings highlight the need for comprehensive, long-term safety assessment of F6H8 and related semifluorinated alkanes.

    What the researchers tested

    The researchers exposed human HepaRG hepatocytes to F6H8 across a broad concentration range representing short- and long-term exposure scenarios. They used combined targeted and untargeted metabolomic profiling with ultra-high-performance liquid chromatography–quadrupole time-of-flight mass spectrometry (UHPLC-QTOFMS) on intracellular extracts and extracellular media.

    What worked and what didn't

    F6H8 induced pronounced, concentration-dependent metabolic alterations, and many responses were non-monotonic. Low concentrations mainly affected amino acid, fatty acid, and lipid metabolism, while central carbon metabolism was disrupted only at the highest exposures. The putative metabolite perfluorohexyloctanoic acid was detected and was associated with the cellular metabolic profiles; its effects only partially overlapped with those of the parent compound.

    What to keep in mind

    These findings come from human HepaRG hepatocytes in a laboratory setting, not from people. The abstract does not describe clinical outcomes or long-term in vivo effects, and it presents the detected biotransformation product as putative.

    • F6H8 caused broad metabolic reprogramming in human HepaRG hepatocytes.
    • Metabolic effects were concentration-dependent and often non-monotonic.
    • A putative biotransformation product, perfluorohexyloctanoic acid, was detected.
    • Low F6H8 concentrations mainly affected amino acid, fatty acid, and lipid metabolism.
    • Central carbon metabolism changed only at the highest exposures.
    • The authors say the results support long-term safety assessment of F6H8 and related compounds.

  • Home-produced eggs in Croatia had higher PFAS levels

    What the study found

    Home-produced eggs had higher levels of per- and polyfluoroalkyl substances (PFAS, a group of persistent human-made chemicals) than commercial eggs in Croatia. Cage eggs showed the lowest levels among the egg types studied.

    Why the authors say this matters

    The authors conclude that the dietary contribution of the four main PFAS to the tolerable weekly intake limit suggests children up to nine years old are the most vulnerable to exposure, especially infants and toddlers consuming home-produced eggs. They also advise consumers to prefer cage eggs because the study found significantly lower exposure with them.

    What the researchers tested

    The researchers measured PFAS levels in eggs collected in Croatia. They analyzed 30 PFAS compounds using high-performance liquid chromatography coupled with high-resolution mass spectrometry and compared commercial eggs (cage, barn, and organic) with home-produced eggs.

    What worked and what didn't

    In home-produced eggs, the highest detection frequencies above the limit of quantification were seen for PFOS, PFNA, PFDA, and PFDoDA. PFOA was detected only in home-produced eggs, and these eggs also had significantly higher mean lower-bound and upper-bound levels for all measured compounds and for the sum of the four main PFAS. Cage eggs had the lowest lower-bound and upper-bound levels.

    What to keep in mind

    The summary provided does not describe limitations beyond the study being based on eggs collected in Croatia. The findings are limited to the compounds measured, the egg types compared, and the dietary exposure estimate reported in the abstract.

    • Home-produced eggs in Croatia had higher PFAS levels than commercial eggs.
    • Cage eggs showed the lowest PFAS levels among the egg types studied.
    • PFOS, PFNA, PFDA, and PFDoDA were the most frequently detected PFAS in home-produced eggs.
    • PFOA was detected only in home-produced eggs.
    • The authors say children up to nine years old are the most vulnerable to dietary exposure, especially infants and toddlers consuming home-produced eggs.

  • Choice models can be estimated despite consumer search

    What the study found

    The study finds conditions under which choice data can identify preferences even when consumers may not know all product attributes. It also reports that the method can be used to test for full information, forecast responses to new information, and conduct welfare analysis when consumers are imperfectly informed.

    Why the authors say this matters

    The authors say the study suggests a way to test whether consumers have full information, forecast how they will respond to information, and conduct welfare analysis when they are imperfectly informed. They also conclude that the method can help identify which attribute was not immediately visible in search results and compute the value of additional information.

    What the researchers tested

    The researchers developed a method for estimating discrete choice models, which are statistical models of choices among alternatives, under consumer search. They applied it in a lab experiment and in data from Expedia.

    What worked and what didn't

    In the lab experiment, the method successfully forecast the average response to new information when consumers engaged in costly search. In Expedia data, it identified which attribute was not immediately visible in search results and allowed computation of the value of additional information.

    What to keep in mind

    The abstract does not describe specific limitations or failures of the method. The summary also does not provide details on the exact conditions required for identification beyond stating that such conditions exist.

    • The study says choice data can identify preferences even when consumers are not fully informed about goods' attributes.
    • The method can be used to test for full information and to forecast responses to new information.
    • In a lab experiment, the method successfully forecast average responses when search was costly.
    • In Expedia data, the method identified an attribute that was not immediately visible in search results.
    • The method also allowed the authors to compute the value of additional information.

  • PFOS disrupts cholinergic neurons through oxidative and signaling pathways

    What the study found

    The study found that PFOS, a persistent industrial chemical, can damage basal forebrain cholinergic neurons, which are cells involved in cognitive function. The authors report that this damage is linked to oxidative stress, disruption of prostaglandin E2 signaling, and disruption of nerve growth factor signaling.

    Why the authors say this matters

    The authors conclude that the findings provide mechanistic insight into PFOS-induced basal forebrain cholinergic neuron neurodegeneration and the related cognitive decline. The study suggests that the results may help point to potential therapeutic strategies to counter these effects.

    What the researchers tested

    The researchers used the SN56 cholinergic cell line, which is derived from the basal forebrain, to study PFOS exposure. Cells were treated with PFOS across a concentration range of 0.1–40 μM, using both a single 1-day treatment and repeated 14-day treatment, along with triiodothyronine (T3), recombinant nerve growth factor (NGF), MF-63, and N-acetylcysteine.

    What worked and what didn't

    PFOS exposure in both the single and repeated treatment conditions increased reactive oxygen species and was associated with reduced NRF2 pathway activity, indicating oxidative stress. PFOS also disrupted prostaglandin E2 (PGE2) signaling and the NGF/TrkA/P75NTR neurotrophic pathways, leading to cell death. These neurotoxic effects were partially mitigated by T3 treatment, among other mechanisms.

    What to keep in mind

    The findings come from a cell-line study, so they describe effects in SN56 cholinergic cells rather than in people. The abstract does not describe detailed limitations beyond this experimental scope.

    • PFOS exposure was linked to cell death in basal forebrain cholinergic neurons.
    • Both 1-day and 14-day PFOS treatments increased reactive oxygen species and reduced NRF2 pathway activity.
    • PFOS disrupted prostaglandin E2 signaling and NGF/TrkA/P75NTR pathways.
    • Triiodothyronine partially protected against the neurotoxic effects.
    • The work used the SN56 basal forebrain cholinergic cell line with PFOS concentrations from 0.1 to 40 μM.

  • Sunlight-driven photocatalyst enabled PFAS defluorination in water

    What the study found

    The study found that a visible-light Z-scheme photocatalyst made from CuInS2 quantum dots on BiOCl nanoplates can overcome the resistance of PFAS, or per- and polyfluoroalkyl substances, to breakdown. The authors report that this system supports carbon-fluorine bond cleavage and carbon chain breakage in water.

    Why the authors say this matters

    The authors conclude that the work reports a sunlight-powered and flow-compatible platform for sustained PFAS decontamination. They present it as a sustainable route for abating so-called "forever chemicals" in water.

    What the researchers tested

    The researchers tested a CuInS2/BiOCl photocatalyst under ultraviolet and natural sunlight conditions. They used femtosecond transient absorption, steady-state spectroscopy, and theoretical calculations to examine charge transfer, and they also ran continuous-flow tests and toxicity assays.

    What worked and what didn't

    The study reports that an internal electric field steered photo-generated electrons to CuInS2 and holes to BiOCl, which the authors say maximized redox potential for PFAS breakdown. Under ultraviolet irradiation, the system achieved 75.8% defluorination and 76.8% total organic carbon removal of sodium p-perfluorous nonenoxybenzenesulfonate within 8 hours, and it reportedly removed more than 96% of that compound in 10 hours under natural sunlight in continuous-flow tests. The abstract also says the approach showed universal applicability for 17 representative PFAS mixtures and that residual toxicity was negligible.

    What to keep in mind

    The abstract does not describe detailed experimental limitations or failure cases. The performance numbers reported are for the specific conditions named in the study, including ultraviolet irradiation, natural sunlight, and the tested PFAS mixtures.

    • A CuInS2/BiOCl photocatalyst was reported to enable PFAS breakdown in water.
    • The authors say an internal electric field separated charges so electrons and holes acted on different parts of the PFAS molecule.
    • Under ultraviolet light, the system achieved 75.8% defluorination and 76.8% total organic carbon removal of OBS in 8 hours.
    • In continuous-flow tests under natural sunlight, the system removed more than 96% of OBS in 10 hours.
    • The abstract reports efficient degradation across 17 representative PFAS mixtures and negligible hazardous effects of the residual.