Health & Environmental Research Online (HERO)


Per- and Polyfluoroalkyl Substances (PFAS)


108 References Were Found:

The "refereed" or "peer review" status of a journal comes from the Ulrichsweb Global Serials Directory (http://ulrichsweb.serialssolutions.com/), as supplied by the publisher. The term refers to the system of critical evaluation of manuscripts/articles by professional colleagues or peers. The content of refereed publications is sanctioned, vetted, or otherwise approved by a peer-review or editorial board. The peer-review and evaluation system is utilized to protect, maintain, and raise the quality of scholarly material published in serials. Publications subject to the referee process are assumed, then, to contain higher quality content than those that are not.
Peer Reviewed Journal Article

Efficient and scalable synthesis of 3-(polyfluoroacyl)pyruvaldehydes dimethyl acetals: A novel functionalized fluorinated building-block

Authors: Chizhov, DL; Belyaev, DV; Yachevskii, DS; Rusinov, GL; Chupakhin, ON; Charushin, VN (2017) HERO ID: 3860754

[Less] An efficient approach for the synthesis of 3-(polyfluoroacyl)pyruvaldehydes dimethyl acetals (1,1-dimethoxy-4polyfluoroalkyl-butan-2,4-dions) . . . [More] An efficient approach for the synthesis of 3-(polyfluoroacyl)pyruvaldehydes dimethyl acetals (1,1-dimethoxy-4polyfluoroalkyl-butan-2,4-dions) from 1,1-dimethoxyacetone and polyfluorinated carboxylic acid esters has been developed. The procedure includes the Claisen type condensation of the starting materials by means of calcium hydride in methanol, followed by isolation of copper complexes of the corresponding diketones and their destroying with disodium EDTA. A simple synthesis of 5(3)-(polyfluoroalkyl)-1H-pyrazole-3(5)-carbaldehydes and their acetals is also presented.

The "refereed" or "peer review" status of a journal comes from the Ulrichsweb Global Serials Directory (http://ulrichsweb.serialssolutions.com/), as supplied by the publisher. The term refers to the system of critical evaluation of manuscripts/articles by professional colleagues or peers. The content of refereed publications is sanctioned, vetted, or otherwise approved by a peer-review or editorial board. The peer-review and evaluation system is utilized to protect, maintain, and raise the quality of scholarly material published in serials. Publications subject to the referee process are assumed, then, to contain higher quality content than those that are not.
Peer Reviewed Journal Article

Syntheses of Biologically Active 2-Arylcyclopropylamines

Authors: Miyamura, S; Itami, K; Yamaguchi, J (2017) HERO ID: 3860772

[Less] The 2-arylcyclopropylamine (ACPA) motif is often seen in biologically active compounds. This review . . . [More] The 2-arylcyclopropylamine (ACPA) motif is often seen in biologically active compounds. This review focuses on the synthesis of biologically active ACPAs and categorizes, by reaction type, the synthetic methods used toward such compounds.

1 Introduction

2 Cyclopropanation Using Diazo Compounds

2.1 Styrene

2.2 Cinnamate

2.3 Vinyl Phthalimide

2.4 Vinyl Acetamide

2.5 Oxazolone

2.6 Diketopiperazine

3 Cyclopropanation Using Ylides

3.1 Cinnamate

3.2 Nitrostyrene

3.3 Oxirane

3.4 Nitroacetate

4 Transformation of Cyclopropanes

4.1 Iodocyclopropane

4.2 Aminocyclopropane

5 Miscellaneous Methods

5.1 Kulinkovich Reaction

5.2 Three-Component Reaction

5.3 Intramolecular Nucleophilic Cyclization

5.4 Intramolecular Mitsunobu Reaction

5.5 Rearrangement from Cyclobutanone

6 Summary

The "refereed" or "peer review" status of a journal comes from the Ulrichsweb Global Serials Directory (http://ulrichsweb.serialssolutions.com/), as supplied by the publisher. The term refers to the system of critical evaluation of manuscripts/articles by professional colleagues or peers. The content of refereed publications is sanctioned, vetted, or otherwise approved by a peer-review or editorial board. The peer-review and evaluation system is utilized to protect, maintain, and raise the quality of scholarly material published in serials. Publications subject to the referee process are assumed, then, to contain higher quality content than those that are not.
Peer Reviewed Journal Article

National Estimate of Per- and Polyfluoroalkyl Substance (PFAS) Release to U.S. Municipal Landfill Leachate

Authors: Lang, JR; Allred, BM; Field, JA; Levis, JW; Barlaz, MA (2017) Environmental Science and Technology 51:2197-2205. HERO ID: 3860763

[Less] Landfills are the final stage in the life cycle of many products containing per- and polyfluoroalkyl . . . [More] Landfills are the final stage in the life cycle of many products containing per- and polyfluoroalkyl substances (PFASs) and their presence has been reported in landfill leachate. The concentrations of 70 PFASs in 95 samples of leachate were measured in a survey of U.S. landfills of varying climates and waste ages. National release of PFASs was estimated by coupling measured concentrations for the 19 PFASs where more than 50% of samples had quantifiable concentrations, with climate-specific estimates of annual leachate volumes. For 2013, the total volume of leachate generated in the U.S. was estimated to be 61.1 million m(3), with 79% of this volume coming from landfills in wet climates (>75 cm/yr precipitation) that contain 47% of U.S. solid waste. The mass of measured PFASs from U.S. landfill leachate to wastewater treatment plants was estimated to be between 563 and 638 kg for 2013. In the majority of landfill leachate samples, 5:3 fluorotelomer carboxylic acid (FTCA) was dominant and variations in concentrations with waste age affected total estimated mass. There were six PFASs that demonstrated significantly higher concentrations in leachate from younger waste compared to older waste and six PFAS demonstrated significant variation with climate.

The "refereed" or "peer review" status of a journal comes from the Ulrichsweb Global Serials Directory (http://ulrichsweb.serialssolutions.com/), as supplied by the publisher. The term refers to the system of critical evaluation of manuscripts/articles by professional colleagues or peers. The content of refereed publications is sanctioned, vetted, or otherwise approved by a peer-review or editorial board. The peer-review and evaluation system is utilized to protect, maintain, and raise the quality of scholarly material published in serials. Publications subject to the referee process are assumed, then, to contain higher quality content than those that are not.
Peer Reviewed Journal Article

Impact of 6:2 fluorotelomer alcohol aerobic biotransformation on a sediment microbial community

Authors: Zhang, S; Merino, N; Wang, N; Ruan, T; Lu, X (2017) Science of the Total Environment 575:1361-1368. HERO ID: 3857384

[Less] Sediment microbial communities are responsible for many chemical biotransformation processes in the . . . [More] Sediment microbial communities are responsible for many chemical biotransformation processes in the aquatic environment and play a critical role in various ecosystems and biogeochemical cycling. However, the impact of polyfluoroalkyl substances on sediment microbial communities remains unclear. These substances are increasingly being used in consumer and industrial products to replace environmentally persistent perfluoroalkyl substances. In this study, we investigated the effects of low (5mg/L) and high (15mg/L) doses of 6:2 fluorotelomer alcohol [6:2 FTOH, F(CF2)6CH2CH2OH] on the structure of a sediment microbial community. 6:2 FTOH biotransformation was rapid in the sediment mixture with a half-life <3days, regardless of the initial doses. After 28days, major products produced in the high dose condition included 28mol% 5:2 sFTOH [F(CF2)5CH(OH)CH3], 9.6mol% 5:3 Acid [F(CF2)5CH2CH2COOH] and 11mol% PFHxA [F(CF2)5COOH], while 73mol% 5:2 sFTOH, 23mol% 5:3 Acid and 26mol% PFHxA were observed in the low dose condition. In the original (control) sediment without 6:2 FTOH dosing, Proteobacteria was the predominant microorganism (18%), followed by Chloroflexi (14%), Verrucomicrobia (13%), Firmicutes (3.4%), Bacterioidetes (2.4%), Actinobacteria (1.7%) and Planctomycetes (1.3%). The presence of 6:2 FTOH and the accumulation of transient transformation products in the sediment exerted selection pressure on the microbial taxonomic distribution and diversity. Our observations indicate that potential 6:2 FTOH degraders and tolerant strains, such as Dokdonella spp., Thauera spp., Albidovulum spp. and Caldanaerovirga spp., existed in the sediment mixture and began to dominate over time. This suggests that these genera might have higher tolerance towards elevated 6:2 FTOH and its transformation products. These findings on the characterization of sediment microbial community stability and dynamics will help predict changes in response to perfluoroalkyl and polyfluoroalkyl substances and also help identify robust microbial strains to degrade polyfluoroalkyl substances in the environment.

The "refereed" or "peer review" status of a journal comes from the Ulrichsweb Global Serials Directory (http://ulrichsweb.serialssolutions.com/), as supplied by the publisher. The term refers to the system of critical evaluation of manuscripts/articles by professional colleagues or peers. The content of refereed publications is sanctioned, vetted, or otherwise approved by a peer-review or editorial board. The peer-review and evaluation system is utilized to protect, maintain, and raise the quality of scholarly material published in serials. Publications subject to the referee process are assumed, then, to contain higher quality content than those that are not.
Peer Reviewed Journal Article

6:2 Chlorinated polyfluorinated ether sulfonate, a PFOS alternative, induces embryotoxicity and disrupts cardiac development in zebrafish embryos

Authors: Shi, G; Cui, Q; Pan, Y; Sheng, N; Sun, S; Guo, Y; Dai, J (2017) Aquatic Toxicology 185:67-75. HERO ID: 3860744

[Less] As an alternative to perfluorooctanesulfonate (PFOS), 6:2 chlorinated polyfluorinated ether sulfonate . . . [More] As an alternative to perfluorooctanesulfonate (PFOS), 6:2 chlorinated polyfluorinated ether sulfonate (commercial name: F-53B) has been used as a mist suppressant in Chinese electroplating industries for over 30 years. It has been found in the environment and fish, and one acute assay indicated F-53B was moderately toxic. However, the toxicological information on this compound was incomplete and insufficient for assessment of their environment impact. The object of this study was to examine the developmental toxicity of F-53B using zebrafish embryos. Zebrafish embryos were incubated in 6-well plates with various concentrations of F-53B (1.5, 3, 6, and 12mg/L) from 6 to 132h post fertilization (hpf). Results showed that F-53B exposure induced developmental toxicity, including delayed hatching, increased occurrence of malformations, and reduced survival. Malformations, including pericardial and yolk sac edemas, abnormal spines, bent tails, and uninflated swim bladders, appeared at 84 hpf, and increased with time course and dose. A decrease in survival percentages was noted in the 6 and 12mg/L F-53B-treated groups at 132 hpf. Continuous exposure to 3mg/L F-53B resulted in high accumulation levels in zebrafish embryos, suggesting an inability for embryos to eliminate this compound and a high cumulative risk to fish. We also examined the cardiac function of embryos at specific developmental stages following exposure to different concentrations, and found that F-53B induced cardiac toxicity and reduced heart rate. Even under low F-53B concentration, o-dianisidine staining results showed significant decrease of relative erythrocyte number at 72 hpf before the appearance of observed effects of F-53B on the heart. To elucidate the underlying molecular changes, genes involved in normal cardiac development were analyzed using real-time qPCR in the whole-body of zebrafish embryos. F-53B inhibited the mRNA expression of β-catenin (ctnnb2) and wnt3a. The mRNA levels of β-catenin targeted genes (nkx2.5 and sox9b), which play critical roles in cardiogenesis, were also reduced after exposure. Thus, exposure to F-53B impaired the development of zebrafish embryos and disrupted cardiac development, which might be mediated by effects on the Wnt signaling pathway and decrease of erythrocyte numbers.

The "refereed" or "peer review" status of a journal comes from the Ulrichsweb Global Serials Directory (http://ulrichsweb.serialssolutions.com/), as supplied by the publisher. The term refers to the system of critical evaluation of manuscripts/articles by professional colleagues or peers. The content of refereed publications is sanctioned, vetted, or otherwise approved by a peer-review or editorial board. The peer-review and evaluation system is utilized to protect, maintain, and raise the quality of scholarly material published in serials. Publications subject to the referee process are assumed, then, to contain higher quality content than those that are not.
Peer Reviewed Journal Article

Quantitative bias analysis of a reported association between perfluoroalkyl substances (PFAS) and endometriosis: The influence of oral contraceptive use

Authors: Ngueta, G; Longnecker, MP; Yoon, M; Ruark, CD; Clewell, HJ; Andersen, ME; Verner, MA (2017) Environment International 104:118-121. HERO ID: 3860773

[Less] An association between serum levels of perfluoroalkyl substances (PFAS) and endometriosis has recently . . . [More] An association between serum levels of perfluoroalkyl substances (PFAS) and endometriosis has recently been reported in an epidemiologic study. Oral contraceptive use to treat dysmenorrhea (pelvic pain associated with endometriosis) could potentially influence this association by reducing menstrual fluid loss, a route of excretion for PFAS. In this study, we aimed to evaluate the influence of differential oral contraceptive use on the association between PFAS and endometriosis. We used a published life-stage physiologically based pharmacokinetic (PBPK) model to simulate plasma levels of perfluorooctanoic acid (PFOA) and perfluorooctane sulfonate (PFOS) from birth to age at study participation (range 18-44years). In the simulated population, PFAS level distributions matched those for controls in the epidemiologic study. Prevalence and geometric mean duration (standard deviation [SD]) of oral contraceptive use in the simulated women were based on data from the National Health and Nutrition Examination Survey; among the women with endometriosis the values were, respectively, 29% and 6.8 (3.1) years; among those without endometriosis these values were 18% and 5.3 (2.8) years. In simulations, menstrual fluid loss (ml/cycle) in women taking oral contraceptives was assumed to be 56% of loss in non-users. We evaluated the association between simulated plasma PFAS concentration and endometriosis in the simulated population using logistic regression. Based on the simulations, the association between PFAS levels and endometriosis attributable to differential contraceptive use had an odds ratio (95% CI) of 1.05 (1.02, 1.07) for a loge unit increase in PFOA and 1.03 (1.02, 1.05) for PFOS. In comparison, the epidemiologic study reported odds ratios of 1.62 (0.99, 2.66) for PFOA and 1.25 (0.87, 1.80) for PFOS. Our results suggest that the influence of oral contraceptive use on the association between PFAS levels and endometriosis is relatively small.

The "refereed" or "peer review" status of a journal comes from the Ulrichsweb Global Serials Directory (http://ulrichsweb.serialssolutions.com/), as supplied by the publisher. The term refers to the system of critical evaluation of manuscripts/articles by professional colleagues or peers. The content of refereed publications is sanctioned, vetted, or otherwise approved by a peer-review or editorial board. The peer-review and evaluation system is utilized to protect, maintain, and raise the quality of scholarly material published in serials. Publications subject to the referee process are assumed, then, to contain higher quality content than those that are not.
Peer Reviewed Journal Article

Synthesis and photochromism of a novel amphiphilic diarylethene bearing two cholic acid groups

Authors: Duan, F; Liu, G; Fan, C; Pu, S (2016) HERO ID: 3860756

[Less] A novel amphiphilic diarylethene with two cholic acid groups, 1,2-bis[2-methyl-5-[3-(1,2,3-triazole) . . . [More] A novel amphiphilic diarylethene with two cholic acid groups, 1,2-bis[2-methyl-5-[3-(1,2,3-triazole) methyl-5-cholic acid-3-thienyl]perfluorocyclopentene, has been successfully synthesized by click reaction for the first time and its photochromic, fluorescence, and electrochemistry properties were systematically investigated. This new compound showed good hydrophilia in methanol/water binary solution (v/v, 1:19). It exhibited photochromism with the notable color change from colorless to red and good fatigue -resistance by photoirradiation. Further study indicated that it also has excellent fluorescence switching property in methanol/water binary solution. (C) 2016 Elsevier Ltd. All rights reserved.

The "refereed" or "peer review" status of a journal comes from the Ulrichsweb Global Serials Directory (http://ulrichsweb.serialssolutions.com/), as supplied by the publisher. The term refers to the system of critical evaluation of manuscripts/articles by professional colleagues or peers. The content of refereed publications is sanctioned, vetted, or otherwise approved by a peer-review or editorial board. The peer-review and evaluation system is utilized to protect, maintain, and raise the quality of scholarly material published in serials. Publications subject to the referee process are assumed, then, to contain higher quality content than those that are not.
Peer Reviewed Journal Article

Microfluidic Isoelectric Focusing of Amyloid Beta Peptides Followed by Micropillar-Matrix-Assisted Laser Desorption Ionization-Mass Spectrometry

Authors: Mikkonen, S; Jacksén, J; Roeraade, J; Thormann, W; Emmer, Å (2016) Analytical Chemistry 88:10044-10051. HERO ID: 3860771

[Less] A novel method for preconcentration and purification of the Alzheimer's disease related amyloid beta . . . [More] A novel method for preconcentration and purification of the Alzheimer's disease related amyloid beta (Aβ) peptides by isoelectric focusing (IEF) in 75 nL microchannels combined with their analysis by micropillar-matrix-assisted laser desorption ionization-time-of-flight-mass spectrometry (MALDI-TOF-MS) is presented. A semiopen chip-based setup, consisting of open microchannels covered by a lid of a liquid fluorocarbon, was used. IEF was performed in a mixture of four small and chemically well-defined amphoteric carriers, glutamic acid, aspartyl-histidine (Asp-His), cycloserine (cSer), and arginine, which provided a stepwise pH gradient tailored for focusing of the C-terminal Aβ peptides with a pI of 5.3 in the boundary between cSer and Asp-His. Information about the focusing dynamics and location of the foci of Aβ peptides and other compounds was obtained using computer simulation and by performing MALDI-MS analysis directly from the open microchannel. With the established configuration, detection was performed by direct sampling of a nanoliter volume containing the focused Aβ peptides from the microchannel, followed by deposition of this volume onto a chip with micropillar MALDI targets. In addition to purification, IEF preconcentration provides at least a 10-fold increase of the MALDI-MS-signal. After immunoprecipitation and concentration of the eluate in the microchannel, IEF-micropillar-MALDI-MS is demonstrated to be a suitable platform for detection of Aβ peptides in human cerebrospinal fluid as well as in blood plasma.

The "refereed" or "peer review" status of a journal comes from the Ulrichsweb Global Serials Directory (http://ulrichsweb.serialssolutions.com/), as supplied by the publisher. The term refers to the system of critical evaluation of manuscripts/articles by professional colleagues or peers. The content of refereed publications is sanctioned, vetted, or otherwise approved by a peer-review or editorial board. The peer-review and evaluation system is utilized to protect, maintain, and raise the quality of scholarly material published in serials. Publications subject to the referee process are assumed, then, to contain higher quality content than those that are not.
Peer Reviewed Journal Article

Estimated pKa values for the environmentally relevant C1 through C8 perfluorinated sulfonic acid isomers

Authors: Rayne, S; Forest, K (2016) Journal of Environmental Science and Health, Part A: Toxic/Hazardous Substances and Environmental Engineering 51:1018-1023. HERO ID: 3860779

[Less] In order to estimate isomer-specific acidity constants (pKa) for the perfluorinated sulfonic acid (PFSA) . . . [More] In order to estimate isomer-specific acidity constants (pKa) for the perfluorinated sulfonic acid (PFSA) environmental contaminants, the parameterization method 6 (PM6) pKa prediction method was extensively validated against a wide range of carbon oxyacids and related sulfonic/sulfinic acids. Excellent pKa prediction performance was observed for the carbon oxyacids using the PM6 method, but this approach was found to have a severe positive bias for sulfonic/sulfinic acids. To overcome this obstacle, a correlation was developed between non-adjusted PM6 pKa values and the corresponding experimentally obtained/estimated acidity constants for a range of representative alkyl, aryl and halogen-substituted sulfonic acids. Application of this correction to the PM6 values allows for extension of this computational method to a new acid functional group. When used to estimate isomer-specific pKa values for the C1 through C8 PFSAs, the modified PM6 approach suggests an adjusted pKa range from -5.3 to -9.0, indicating that all members of this class of well-known environmental contaminants will be effectively completely dissociated in aquatic systems.

The "refereed" or "peer review" status of a journal comes from the Ulrichsweb Global Serials Directory (http://ulrichsweb.serialssolutions.com/), as supplied by the publisher. The term refers to the system of critical evaluation of manuscripts/articles by professional colleagues or peers. The content of refereed publications is sanctioned, vetted, or otherwise approved by a peer-review or editorial board. The peer-review and evaluation system is utilized to protect, maintain, and raise the quality of scholarly material published in serials. Publications subject to the referee process are assumed, then, to contain higher quality content than those that are not.
Peer Reviewed Journal Article

Fuel cell membranes of phosphoric acid-doped poly(benzimidazole/ether/siloxane/amide)/sulfonated polystyrene/silica nanoparticle nanocomposites: A physical property study

Author: Kausar, A (2016) HERO ID: 3860734

[Less] Poly(benzimidazole/ether/siloxane/amide) (PBESA) having siloxane and ether groups in the backbone has . . . [More] Poly(benzimidazole/ether/siloxane/amide) (PBESA) having siloxane and ether groups in the backbone has been prepared using 4-(3,4-diaminophenoxy)benzene-1,2-diamine, bis(carboxypropy)tetramethyldisiloxane, and 4,4-oxydianiline via polyphosphoric acid processes with heating up to 160 degrees C. The sulfonation of polystyrene (PS-S) was conducted using 98% sulfuric acid. Afterward, a series of hybrid membranes using PBESA/PS-S/silica nanoparticles (SiNPs) have been developed with 0.1-2 wt% nanofiller. Later, the membranes were doped with phosphoric acid and subjected to various characterization techniques. Field emission scanning electron micrographs (FESEMs) showed gyroid-like patterning of nanoporous membranes with uniform ionic pathways. Fine water retention capability and higher proton conductivity of new hybrids, owing to consistent porous membrane structure, were observed. Increasing the amount of nanoparticles (0.1-2 wt%) also enhanced the tensile stress of acid-doped PBESA/PS-S/SiNPs nanocomposites from 64.9 to 68.1 MPa. There existed a relationship between nanofiller loading and thermal stability of the membranes. The glass transition temperature of phosphoric acid-doped PBESA/PS-S/SiNPs nanocomposites increased from 202 to 214 degrees C. The membranes also had fine ion exchange capacity (IEC) of around 2.5-3.7 mmol g(-1). Novel membranes with high IEC value achieved high proton conductivity of 1.26-2.74 S cm(-1) in a wide range of humidity values at 80 degrees C, which was higher than that for perfluorinated Nafion((R)) 117 membrane (1.1 x 10(-1) S cm(-1) at 80 degrees C, 94% relative humidity (RH)). The fuel cell (hydrogen/oxygen) using PBESA/PS-S/SiNPs 2 (IEC 3.7 mmol g(-1)) showed better performance than that of Nafion((R)) 117 at 40 degrees C (30% RH).