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Human exposure to organic gunshot residues is a largely under researched topic in environmental and occupational health. This study aimed to examine how the components of a complex liquid blend affect the permeation behavior of its constituents. In the initial study, Hoppes No. 9 Gun Bore Cleaner, a firearm cleaning solvent, was chosen to test two types of disposable nitrile gloves from Kimberly-Clark’s Kimtech Science: the thinnest (Lavender) and thickest (Blue). Testing was conducted using the 1-inch diameter closed-loop ASTM F739 cell at 35℃ without recirculation with n-decane collection, and subsequent analysis via capillary gas chromatography-mass spectrometry to quantify the permeated compounds. Results showed that the thicker Blue glove resisted Hoppe’s permeation more than the thinner Lavender glove. The Lavender glove permeated 3.2 times more mass at 60 minutes despite having the same standardized breakthrough times (7.5 ± 2.5 min). Unexpectedly, the kerosene fraction permeated at a much higher rate than anticipated, appearing at the standardized breakthrough time for Hoppe’s, contrary to the Kimberly-Clark chemical resistance guide's listing for Sterling disposable nitrile glove material. Notably, components reported by the glove manufacturer to quickly permeate nitrile material, like ethanol, did not permeate slower than expected, hinting at a possible carrier function. A semiquantitative risk assessment confirmed the inadequacy of both gloves, suggesting that individuals using personal protective equipment may not receive the anticipated resistance to chemical permeation when dealing with complex mixtures, thus heightening exposure risk. Further research is necessary to develop improved glove testing measures to ensure worker safety and health.Additionally, this research examined how methyl centralite and ethyl centralite, two major gunshot residue components, simulated gunshot residues when permeating disposable nitrile glove material in three different

BACKGROUND: Motor function is critical for childrens health, yet remains an understudied neurodevelopmental domain. Exposure to metals has been linked with motor function, but no study has examined the joint effects of metal mixtures. METHODS: We evaluated cross-sectional associations between a metal mixture and motor function among 569 adolescents (10-14 years old) living near the ferroalloy industry. Concentrations of blood lead, hair manganese, hair copper, and hair chromium were quantified using inductively coupled plasma mass spectrometry. Neuropsychologists administered multiple fine motor function assessments: pursuit aiming, finger tapping, visual reaction time (VRT), and subtests from the Luria Nebraska battery. We estimated associations between motor function and the metal mixture using quantile-based g-computation and multivariable linear regression, adjusting for child age, sex, and socioeconomic status. We explored sex-specific associations in stratified models. RESULTS: Associations between the metal mixture and motor function were mostly null but were modified by sex. We observed a beneficial association among females: a quartile increase in all metals in the mixture was associated with a 2.6% faster average response time on the VRT (95% confidence interval [CI] = -4.7%, -0.5%), driven by Cu and Cr. In contrast, this association was adverse among males (ß = 1.5% slower response time [95% CI = -0.7%, 3.9%]), driven by Cu and Mn. CONCLUSIONS: Results suggest that males may be more susceptible to the adverse effects of metal exposure on motor function during adolescence than females. Future studies, particularly prospective study designs, are warranted to further understand the associations of metal mixtures with motor function.

Hot-mix cold-laid (HMCL) asphalt mixes are crucial for maintaining asphalt pavements via blade-on/level-up patching. While the Superpave Gyratory Compactor (SGC) is widely used for hot-mix asphalt mixes due to its adjustable parameters and manageable compaction densities, the HMCL mix design still follows the Hveen mix design method, as per the Texas Department of Transportation (TxDOT) specification Item 334, using a Texas Gyratory Compactor. This study proposes a new HMCL mix design method that employs an SGC. This study examined five types of HMCL mixes, consisting of binders and aggregates commonly used in the industry. For each mix, three levels of binder content were determined following the TxDOT specification Item 334. These 15 laboratory-mixed HMCL mixes were then used to mold SGC specimens with four different compaction levels to establish the design gyration for SGC laboratory-molded densities in the range of 94.0 ± 1.5 percent. The study also found that the current specification may include mix designs with low compatibility. Specifically, the Hveem stability test in the specification was sometimes not sensitive to mix designs, leading to weak correlations with field performance. In developing a new mix design method, the Cantabro mass loss and IDEAL cracking and rutting tests were employed to characterize the resistance of mixes to raveling, cracking, and rutting. Binder contents significantly affected these test results. Moreover, mixes with low compactability were able to be excluded during testing specimen preparation. Therefore, the new HMCL mix design method using an SGC improved the current HMCL mix design method.

Phthalates are endocrine disrupting chemicals (EDCs) found in common consumer products such as soft plastics and cosmetics. Although the knowledge regarding the adverse effects of phthalates on female fertility are accumulating, information on the hormone sensitive endometrium is still scarce. Here, we studied the effects of phthalates on endometrial cell proliferation and gene expression. Human endometrial primary epithelial and stromal cells were isolated from healthy fertile-aged women (n=3), and were compared to endometrial cell lines T-HESC and Ishikawa. Three different epidemiologically relevant phthalate mixtures were used, defined by urine samples in the Midlife Women Health Study (MWHS) cohort. Mono (2-ethyl-5-hydroxyhexyl) phthalate (MEHHP) was used as a single phthalate control. Cells were harvested for proliferation testing and transcriptomic analyses after 24 h exposure. Even though all cell models responded differently to the phthalate exposures, many overlapping differentially expressed genes (DEGs, FDR<0.1), related to cell adhesion, cytoskeleton and mitochondria were found in all cell types. The qPCR analysis confirmed that MEHHP significantly affected cell adhesion gene vinculin (VCL) and NADH:ubiquinone oxidoreductase subunit B7 (NDUFB7), important for oxidative phosphorylation. Benchmark dose modelling showed that MEHHP had significant concentrationdependent effects on cytoskeleton gene actin-beta (ACTB). In conclusion, short 24 h phthalate exposures significantly altered gene expression cell-specifically in human endometrial cells, with six shared DEGs. The mixture effects were similar to those of MEHHP, suggesting MEHHP could be the main driver in the mixture. Impact of phthalate exposures on endometrial functions including receptivity should be addressed.

The improved production of a polar curable monomer, isosorbide monomethacrylate (MISD), with methacrylic anhydride (MAAH) as an acyl donor, was performed. A sustainable and cheap catalyst, potassium acetate (CH3COOK), was used for a solvent-free synthesis, requiring only the equimolar amount of reagents (no excess). The production included the quantitative separation of the secondary product, methacrylic acid (MAA), preventing the reaction batch from the purification process (neutralization of MAA), and gaining a usable reagent. The synthesis resulted in a sufficient yield of MISD (61.8%) obtained by the liquid-liquid extraction process (LLE), which is a significant improvement in the process, avoiding the flash chromatography step in the isolation of MISD. The purity of synthesized and isolated MISD via the LLE was confirmed by H-1 NMR, MS, and FTIR analyses. The thermal analyses, namely, DSC and TGA, were used to characterize the curability and thermal stability of MISD. The activation energy of MISD's curing was calculated (E-a = 94.6 kJ/mol) along with the heat-resistant index (T-s = 136.8). The polar character of isosorbide monomethacrylate was investigated in a mixture with epoxidized acrylated soybean oil (EASO). It was found that MISD is entirely soluble in EASO and can modify the rheological behavior and surface energy of EASO-based resins. The apparent viscosity of EASO at 30 degrees C (eta(app) = 3413 mPas) decreased with the 50% content of MISD significantly (eta(app) = 500 mPas), and the free surface energy value of EASO (gamma(S) = 42.2 mJ/m(2)) also increased with the 50% content of MISD (gamma(S) = 48.7 mJ/m(2)). The produced MISD can be successfully used as a diluent and the polarity modifier of curable oil-bas

Per- and polyfluoroalkyl substances (PFAS) may cause various deleterious health effects. Epidemiological studies have demonstrated associations between PFAS exposure and adverse neurodevelopmental outcomes. The cytotoxicity, neurotoxicity, and mitochondrial toxicity of up to 12 PFAS including perfluoroalkyl carboxylates, perfluoroalkyl sulfonates, 6:2 fluorotelomer sulfonic acid (6:2 FTSA), and hexafluoropropylene oxide-dimer acid (HPFO-DA) were tested at concentrations typically observed in the environment (e.g., wastewater, biosolids) and in human blood using high-throughput in vitro assays. The cytotoxicity of all individual PFAS was classified as baseline toxicity, for which prediction models based on partition constants of PFAS between biomembrane lipids and water exist. No inhibition of the mitochondrial membrane potential and activation of oxidative stress response were observed below the cytotoxic concentrations of any PFAS tested. All mixture components and the designed mixtures inhibited the neurite outgrowth in differentiated neuronal cells derived from the SH-SY5Y cell line at concentrations around or below cytotoxicity. All designed mixtures acted according to concentration addition at low effect and concentration levels for cytotoxicity and neurotoxicity. The mixture effects were predictable from the experimental single compounds’ concentration–response curves. These findings have important implications for the mixture risk assessment of PFAS.

Chemical risk assessments typically focus on single substances, often overlooking real-world co-exposures to chemical mixtures. Mixture toxicology studies using representative mixtures can reveal potential chemical interactions, but these do not account for the unique chemical profiles that occur in the blood of diverse individuals. Here we used the H295R steroidogenesis assay to screen personalized mixtures of 24 persistent organic pollutants (POPs) for cytotoxicity and endocrine disruption. Each mixture was reconstructed at a human exposure relevant concentration (1×), as well as at 10- and 100-fold higher concentration (10×, 100×) by acoustic liquid handling based on measured blood concentrations in a Swedish cohort. Among the twelve mixtures tested, nine mixtures decreased the cell viability by 4–18%, primarily at the highest concentration. While the median and maximum mixtures based on the whole study population induced no measurable effects on steroidogenesis at any concentration, the personalized mixture from an individual with the lowest total POPs concentration was the only mixture that affected estradiol synthesis (35% increase at the 100× concentration). Mixtures reconstructed from blood levels of three different individuals stimulated testosterone synthesis at the 1× (11–15%) and 10× concentrations (12–16%), but not at the 100× concentration. This proof-of-principle personalized toxicity study illustrates that population-based representative chemical mixtures may not adequately account for the toxicological risks posed to individuals. It highlights the importance of testing a range of real-world mixtures at relevant concentrations to explore potential interactions and non-monotonic effects. Further toxicological studies of personalized contaminant mixtures could improve chemical risk assessment and advance the understanding of human health, as chemical exposome data become increasingly available.

The study investigated the characteristics of different natural refrigerants and their mixtures in a residential heat pump with low refrigerant charge. Three main evaluation criteria were utilized for comparing different mixtures: Coefficient of Performance (COP), Volumetric Heating Capacity (VHC), and a newly proposed indicator, the heating capacity at charge limit. Propane was used as a reference refrigerant. It was found that some mixtures significantly improved both COP and the heating capacity at charge limit while maintaining similar volumetric heating capacity and operating conditions. Alternative multi-criteria decision-making techniques were adopted to rank the best refrigerant mixtures. Mixtures rich in Dimethyl Ether (DME), such as DME-CO2 [0.96-0.04] and DME-Propylene [0.75-0.25] were found consistently among the best options. Those were followed by Propylene-rich mixtures such as Propylene-CO2, Propylene-Isobutane and Propylene-Butane. The levelized cost of heat (LCOH) could be improved by up to 12 %. To accelerate the transition to natural refrigerants, without compromises on efficiency and costs, further research and certification activities on non-fluorinated refrigerants based on Dimethyl Ether (R-E170), CO2 (R-744) and Propylene (R-1270) are recommended., QC 20240620

The widespread use of per- and polyfluoroalkyl substances (PFAS) in various anthropogenic and industrial processes has led to an urgent demand for the advancement of reliable sensing and remediation technologies for mitigating the adverse effects associated with PFAS contamination. Within water systems, a plethora of residual toxins and pollutants, including surface-active compounds, contribute to the complexity of the matrices. The complexity of these matrices has made sensing and remediation challenging and cost intensive. Therefore, acquiring a comprehensive understanding of PFAS interactions with other surface-active agents within these matrices is essential to safeguarding environmental and human well-being. This thesis explores the intricate equilibrium and dynamic behavior of PFAS at air/water and oil/water interfaces, aiming to deepen our understanding of their interfacial behavior and interactions with other surface-active compounds in aqueous systems. Chapter 1 lays the theoretical foundation by discussing the behavior of surfactant mixtures and surfactant adsorption kinetics, with a particular focus on surface-active PFAS. Chapter 2 and Appendix A elucidate the mechanisms underlying the interaction of PFAS with interfering compounds in aqueous environments, revealing three key characteristics of molecularchemistry that dictate synergistic or antagonistic behavior of PFAS mixtures. These insights provide valuable guidance for enhancing current PFAS sensing and remediation technologies through the formulation of design rules. Furthermore, Chapter 3 and Appendix B investigate the transport mechanisms of PFAS with varying chain lengths to oil/water interfaces. This study provides a predictive kinetic model for classifying different PFAS and distinguishing them from cationic interfering compounds, both individually and in binary mixtures at unknown concentrations. By leveraging both equilibrium and dynamic features extracted from PFAS adsorption data, this stu

BackgroundA growing body of literature investigated childhood exposure to environmental chemicals in association with attention-deficit/hyperactivity disorder (ADHD) symptoms, but limited studies considered urinary mixtures of multiple chemical classes. This study examined associations of concurrent exposure to non-persistent chemicals with ADHD symptoms in children diagnosed with autism spectrum disorder (ASD), developmental delay (DD), and typical development (TD).MethodsA total of 549 children aged 2-5 years from the Childhood Autism Risks from Genetics and Environment (CHARGE) case-control study were administered the Aberrant Behavior Checklist (ABC). This study focused on the ADHD/noncompliance subscale and its two subdomains (hyperactivity/impulsivity, inattention). Sixty-two chemicals from four classes (phenols/parabens, phthalates, organophosphate pesticides, trace elements) were quantified in child urine samples, and 43 chemicals detected in > 70% samples were used to investigate their associations with ADHD symptoms. Negative binomial regression was used for single-chemical analysis, and weighted quantile sum regression with repeated holdout validation was applied for mixture analysis for each chemical class and all chemicals. The mixture analyses were further stratified by diagnostic group.ResultsA phthalate metabolite mixture was associated with higher ADHD/noncompliance scores (median count ratio [CR] = 1.10; 2.5th, 97.5th percentile: 1.00, 1.21), especially hyperactivity/impulsivity (median CR = 1.09; 2.5th, 97.5th percentile: 1.00, 1.25). The possible contributors to these mixture effects were di-2-ethylhexyl phthalate (DEHP) metabolites and mono-2-heptyl phthalate (MHPP). These associations were likely driven by children with ASD as these were observed among children with ASD, but not among TD or those with DD. Additionally, among children with ASD, a mixture of all chemicals was associated with ADHD/noncompliance and hyperactivity/impul

The presence of microplastics (MPs) is increasing at a dramatic rate globally, posing risks for exposure and subsequent potential adverse effects on human health. Apart from being physical objects, MP particles contain thousands of plastic-associated chemicals (i.e., monomers, chemical additives, and non-intentionally added substances) captured within the polymer matrix. These chemicals are often migrating from MPs and can be found in various environmental matrices and human food chains; increasing the risks for exposure and health effects. In addition to the physical and chemical attributes of MPs, plastic surfaces effectively bind exogenous chemicals, including environmental pollutants (e.g., heavy metals, persistent organic pollutants). Therefore, MPs can act as vectors of environmental pollution across air, drinking water, and food, further amplifying health risks posed by MP exposure. Critically, fragmentation of plastics in the environment increases the risk for interactions with cells, increases the presence of available surfaces to leach plastic-associated chemicals, and adsorb and transfer environmental pollutants. Hence, this review proposes the so-called triple exposure nexus approach to comprehensively map existing knowledge on interconnected health effects of MP particles, plastic-associated chemicals, and environmental pollutants. Based on the available data, there is a large knowledge gap in regard to the interactions and cumulative health effects of the triple exposure nexus. Each component of the triple nexus is known to induce genotoxicity, inflammation, and endocrine disruption, but knowledge about long-term and inter-individual health effects is lacking. Furthermore, MPs are not readily excreted from organisms after ingestion and they have been found accumulated in human blood, cardiac tissue, placenta, etc. Even though the number of studies on MPs-associated health impacts is increasing rapidly, this review underscores that there is a pressing n, This work was supported by the Swedish Knowledge Foundation [Grants No. 20160019; 20220122, 20230020], and Vinnova, the Swedish Agency for Innovation Systems, [Grant No. 2021-03968]. We acknowledge scientific support from the Exploring Inflammation in Health and Disease (X-HiDE) Consortium, which is a strategic research profile at Örebro University funded by the Knowledge Foundation [Grant No. 20200017].

In this work, we study a strain gradient problem involving mixtures. The variational formulation is written as a first-order in time coupled system of parabolic variational equations. An existence and uniqueness result is recalled. Then, we introduce a fully discrete approximation by using the finite element method and the implicit Euler scheme. A discrete stability property and a priori error estimates are proved. Finally, some one- and two-dimensional numerical simulations are performed., Peer Reviewed, Postprint (author's final draft)

We are ubiquitously exposed to a plethora of endocrine-disrupting chemicals (EDCs), i.e. substances that alter the function(s) of the endocrine system. While ample evidence show individual EDC's influence on developmental processes resulting in adverse health outcomes, less is known about the effects of human-relevant EDC mixtures exposure. Additionally, there is a lack of appropriate methodology to assess the hazard and risk of complex mixtures. This doctoral project aimed to examine the effects of two EDC mixtures and to compare individual components to its mixture, on the developing metabolic system. And to investigate additivity approach for predicting effects of complex mixtures. Studied EDC mixtures (G and G1) were previously identified using Swedish Environmental Longitudinal Mother and Child Asthma and Allergy (SELMA) study data, based on their association with lower birth weight. In this thesis, these mixtures, and mixture G1’s components, were tested for effects on adipogenesis and underlying epigenetic and transcriptional changes in human mesenchymal stem cells (hMSCs) and on metabolic rate in zebrafish larvae. In hMSCs, both mixtures induced adipogenesis at concentrations corresponding to SELMA cohort measured levels. Mixture G induced early transcriptional changes of over 1000 genes in a dose-dependent manner. These genes significantly overlapped with glucocorticoid-regulated genes and were involved in early osteogenesis. Mixture G1 induced significant DNA methylation changes at 713 positions and in six genomic regions in genes whose expression or methylation was previously associated with obesity or MSC differentiation. In zebrafish larvae, mixture G1 increased oxygen consumption rate. Compared to mixture G1, none of its individual components showed equally large effects on adipogenesis or metabolic rate. However, mixture G1 effect on both endpoints could be adequately predicted by the additivity model using experimental data from its constituents. In

Carbon molecular sieve membranes (CMSMs) are inorganic membranes produced by carbonization of a thermosetting polymer. The selection of the adequate polymer, the conditions of carbonization and post-carbonization treatment allow the production of a large variety of porous structures. The mass transport of species through these porous structures is not easy to model in detail. This review reports the last developments in the field of mass transport through CMSMs. The membrane production is also briefly touched upon, followed by the definition of transport equations and a description of detailed models for these membranes.

Humans are exposed to a mixture of pesticides through diet as well as through the environment. We conducted a suspect-screening based study to describe the probability of (concomitant) exposure to a set of pesticide profiles in five European countries (Latvia, Hungary, Czech Republic, Spain and the Netherlands). We explored whether living in an agricultural area (compared to living in a peri-urban area), being a a child (compared to being an adult), and the season in which the urine sample was collected had an impact on the probability of detection of pesticides (-metabolites). In total 2088 urine samples were collected from 1050 participants (525 parent-child pairs) and analyzed through harmonized suspect screening by five different laboratories. Fourty pesticide biomarkers (either pesticide metabolites or the parent pesticides as such) relating to 29 pesticides were identified at high levels of confidence in samples across all study sites. Most frequently detected were biomarkers related to the parent pesticides acetamiprid and chlorpropham. Other biomarkers with high detection rates in at least four countries related to the parent pesticides boscalid, fludioxonil, pirimiphos-methyl, pyrimethanil, clothianidin, fluazifop and propamocarb. In 84% of the samples at least two different pesticides were detected. The median number of detected pesticides in the urine samples was 3, and the maximum was 13 pesticides detected in a single sample. The most frequently co-occurring substances were acetamiprid with chlorpropham (in 62 urine samples), and acetamiprid with tebuconazole (30 samples). Some variation in the probability of detection of pesticides (-metabolites) was observed with living in an agricultural area or season of urine sampling, though no consistent patterns were observed. We did observe differences in the probability of detection of a pesticide (metabolite) among children compared to adults, suggesting a different exposure and/or elimination patterns bet

This work applied the mixture design with the PDCA cycle for the optimization of the properties of an architectural coating. In the Plan stage, an experimental plan was designed to achieve the properties of interest; three types of fillers; calcium carbonate, talc and kaolin were established as the main components of the mixture. The simplex design with increased centroid was used to execute the experimental runs (Do), 20 experiments were executed in total and were characterized in terms of viscosity, contrast ratio percentage, whiteness percentage, brightness and cost. In the Check stage, the experimental results were evaluated and each property was fitted to a statistical model for the prediction of its values. The viscosity, percent whiteness and gloss were fitted to a quadratic model and the percent contrast ratio was fitted to a special cubic model. Finally, in the Act stage, the properties were optimized according to the established restrictions and at the lowest possible cost. The optimum mixture was composed of 0.2934 calcium carbonate, 0.5450 talc and 0.1616 kaolin. The experimental test was carried out with the optimized mixture to guarantee the accuracy and precision of the results of the statistical model., Este trabajo aplicó el diseño de mezclas con el ciclo PHVA para la optimización de las propiedades de un recubrimiento arquitectónico. En la etapa Planificar se diseñó un plan experimental que permita alcanzar las propiedades de interés, se estableció como componentes principales de la mezcla a tres tipos de cargas; carbonato de calcio, talco y caolín. El diseño simplex con centroide aumentado se utilizó para ejecutar las corridas experimentales (Hacer), se ejecutaron 20 experimentos en total y fueron caracterizados en cuanto a viscosidad, porcentaje de relación de contraste, porcentaje blancura, brillo y costo. En la etapa Verificar, se evaluaron los resultados experimentales y cada propiedad se ajustó a un modelo estadístico para la predicción de sus valores. La viscosidad, porcentaje de blancura y brillo fueron ajustados a un modelo cuadrático y el porcentaje de relación de contraste fue ajustado a un modelo cúbico especial. Finalmente, en la etapa Actuar, se realizó la optimización de las propiedades de acuerdo con las restricciones establecidas y al menor costo posible. La mezcla óptima estuvo compuesta por 0,2934 de carbonato de calcio, 0,5450 de talco y 0,1616 de caolín. La prueba experimental se realizó con la mezcla optimizada para garantizar la exactitud y precisión de los resultados del modelo estadístico.

This paper documents and reinvestigates the solid-state and crystal structures of 4,4′-azobis-4-cyanopentanoic acid (ACPA), a water-soluble azobis-nitrile of immense utility as a radical initiator in living polymerizations and a labile mechanophore that can be embedded within long polymer chains to undergo selective scission under mechanical activation. Surprisingly, for such applications, both the commercially available reagent and their derivatives are used as “single initiators” when this azonitrile is actually a mixture of stereoisomers. Although the racemate and meso compounds were identified more than half a century ago and their enantiomers were separated by classical resolution, there have been confusing narratives dealing with their characterization, the existence of a conglomeratic phase, and fractional crystallization. Our results report on the X-ray crystal structures of all stereoisomers for the first time, along with further details on enantiodiscrimination and the always intriguing arguments accounting for the stability of homochiral versus heterochiral crystal aggregates. To this end, metadynamic (MTD) simulations on stereoisomer molecular aggregates were performed to capture the incipient nucleation events at the picosecond time scale. This analysis sheds light on the driving homochiral aggregation of ACPA enantiomers., Junta de Extremadura, European Regional Development Fund, Depto. de Mineralogía y Petrología, Fac. de Ciencias Geológicas, TRUE, pub

A gold-catalyzed cyclization reaction of alkynyl-indoles has been developed for the stereoselective construction of the quaternary carbon center of fused indolines. This reaction efficiently produces fused indolines via diastereoselective 6-endo-dig cyclization controlled by a bulky TIPS group, followed by nucleophilic attack of the carboxy group on the resulting imine. The lactone moiety of the fused indoline can be reductively cleaved to produce a tricyclic indoline, which could be useful for the synthesis of akuammiline alkaloids.

Background: Many studies have been published on the relationships between different environmental contaminants and diabetes. In these studies, the environmental contaminants have most often been evaluated one by one, but in real life we are exposed to a mixture of contaminants that interact with each other. Objective: The major aim of this study was to see if a mixture of contaminants could improve the prediction of incident diabetes, using machine learning. Methods: In the Prospective Investigation of the Vasculature in Uppsala (PIVUS) study (988 men and women aged 70 years), circulating levels of 42 contaminants from several chemical classes were measured at baseline. Incident diabetes was followed for 15 years. Six different machine-learning models were used to predict prevalent diabetes (n = 115). The variables with top importance were thereafter used to predict incident diabetes (n = 83). Results: Boosted regression trees performed best regarding prediction of prevalent diabetes (area under the ROC -curve = 0.70). Following removal of correlated contaminants, the addition of nine selected contaminants (Cd, Pb, Trans-nonachlor the phthalate MiBP, Hg, Ni, PCB126, PCB169 and PFOS) resulted in a significant improvement of 6.0 % of the ROC curve (from 0.66 to 0.72, p = 0.018) regarding incident diabetes (n = 51) compared with a baseline model including sex and BMI when the first 5 years of the follow-up was used. No such improvement in prediction was seen over 15 years follow-up. The single contaminant being most closely related to incident diabetes over 5 years was Nickel (odds ratio 1.44 for a SD change, 95 % CI 1.05-1.95, p = 0.022). Conclusion: This study supports the view that machine learning was useful in finding a mixture of important contam-inants that improved prediction of incident diabetes. This improvement in prediction was seen only during the first 5 years of follow-up.

The most efficient and stable combustion occurs in a catalytic reactor when the burning mixture is in contact with the catalyst for a sufficiently long period. When the contract period is too short, insufficient energy is generated adjacent to the catalyst surface to sustain combustion in the main or free stream. This study is focused mainly upon the essential combustion characteristics of propane-air mixtures in flow tube reactors with a heat-recirculating structure. Computational fluid dynamics simulations are performed to gain a greater understanding of the mechanisms of flame stabilization. The essential factors affecting flame stability and combustion characteristics are determined in order to obtain design insights. The results indicate that in order to meet the emission level requirements, for industrial low emission gas turbine engines, staged combustion is required in order to minimise the quantity of the oxides of nitrogen produced. The combustion catalyst has several desirable characteristics: they are capable of minimizing nitrogen oxides emission and improving the pattern factor. Operating the combustion process in a very lean condition, namely high excess air, is one of the simplest ways of achieving lower temperatures and hence lower nitrogen oxides emissions. The use of a catalytic combustor offers the advantage that all of the fuel can be oxidized therein, resulting in ultra-low nitrogen oxides emissions and low carbon monoxide and unburned hydrocarbon levels. In mass transfer controlled catalytic reactions, one cannot distinguish between a more active catalyst and a less active catalyst because the intrinsic catalyst activity is not determinative of the rate of reaction. It is possible to achieve essentially adiabatic combustion in the presence of a catalyst at a reaction rate many times greater than the mass transfer limited rate. The maximum achievable velocity depends on flow conditions and catalyst parameters such as type, monolith cell size, a

The demand for diesel utilization in heavy-duty vehicles continues to increase worldwide. However, the potential use of alternative fuels such as biodiesel has disadvantages, such as lower calorific value and higher viscosity. For this reason, it is necessary to improve its properties to optimize combustion in the engine and reduce emissions. This research explores the various blends that can improve biodiesel utilisation through strategies and advancements that optimize diesel engine performance. Among the various strategies to improve biodiesel, we find the mixtures of different bio-oils (vegetable oils, pyrolysis oils, and used cooking oils), blends of biodiesel with alcohol and hydrogen, the use of biodiesel as a pilot fuel, emulsions of biodiesel with water, and the application of antioxidants, nanotubes, and nanoparticles to biodiesel. It is concluded that currently, biodiesel can be used through the dual combustion technique, where it acts as a pilot fuel representing 10% or 20% of the total fuel in the engine. This strategy allows for the promotion of other fuels (liquids and gases) in dual combustion to find the optimal blend that is the best option for the diesel engine., La demanda de diésel en vehículos pesados se incrementa cada año en el mundo. El posible uso de combustibles alternativos como el biodiésel tiene algunas desventajas como el menor valor calorífico y su mayor viscosidad, por esta razón se requiere mejorar sus propiedades, optimizando el comportamiento de la combustión en el motor y en la reducción de las emisiones. El objetivo del trabajo de investigación es explorar las diferentes mezclas que puedan ayudar a mejorar el uso del biodiésel a través de las estrategias y avances que se han generado con el propósito de beneficiar el desempeño del motor diésel. Entre las distintas estrategias de mejoramiento del biodiésel están las mezclas de distintos bioaceites (aceites vegetales, de pirólisis y usado de cocina), mezclas del biodiésel con alcohol, con hidrógeno, el biodiésel como combustible piloto, las emulsiones del biodiésel con agua y la aplicación del biodiésel con antioxidantes, nanotubos y nanopartículas. Se concluye que para poder usar actualmente el biodiésel se lo haría con la combustión dual, en donde este representaría el combustible piloto (10 % o 20 % del combustible total del motor). Con esta estrategia se puede impulsar a otros combustibles (líquidos y gaseosos) en la combustión dual, para que con el paso del tiempo se encuentre la mezcla óptima que sea la mejor opción para el motor diésel.

© 2009 Elsevier B.V. The authors of this study gratefully acknowledge financial support from Comunidad de Madrid and Universidad Complutense de Madrid under Project CCG06-UCM/MAT-1037., This study investigates the influence of different operating parameters in the transport of water and methanol through a Nafion membrane when it is used to separatewater fromamethanol–water solution. For this purpose, measurements of mass flux and concentration change have been performed at different values of circulation velocity, concentration of themethanol–water solutions and temperature conditions. From the experimental data, thewater and methanol partial fluxes have been estimated, and itwas found that the water flux is always lower than the methanol flux, but it cannot be neglected. Whereas total and methanol fluxes seem to have predictable and similar behaviors, the water flux seems to be less predictable and it exhibits a very distinct behavior. Methanol and water permeabilities have been calculated, and from these values the activation energy of methanol and water fluxes in the membrane has been estimated. The results have been discussed in terms of the methanol and water solubilities in the membrane., Comunidad de Madrid, Universidad Complutense de Madrid, Depto. de Estructura de la Materia, Física Térmica y Electrónica, Fac. de Ciencias Físicas, TRUE, pub

© 2008 American Institute of Physics. We have greatly appreciated stimulating discussions with Manuel M. Piñeiro from the University of Vigo (Spain). We are also indebted to the Spanish Ministerio de Educación y Ciencia (Contract No. FIS2006-05323) for supporting this research., We present experimental results of the thermal conductivity of several nanofluids prepared by dispersing nanoparticles of SiO(2) and CuO in water and ethylene glycol at various concentrations up to approximate to 5% in mass fraction. The measurements have been performed by the multicurrent hot-wire technique. Good agreement, within 2%, is found in recommended and published thermal conductivities of the pure fluids. Our experimental technique allows a very accurate determination of the enhancement in the thermal conductivity of the fluids due to the presence of dispersed nanoparticles. Measured enhancements compare well with some of the values published so far in the literature. We have compared our results with simple theoretical models that predict the thermal conductivity of solid suspensions and found that in some cases observed enhancements are several times larger than the predicted ones., Spanish Ministerio de Educación y Ciencia, Depto. de Estructura de la Materia, Física Térmica y Electrónica, Fac. de Ciencias Físicas, TRUE, pub

© 2010 Elsevier B.V. The authors of this study gratefully acknowledge Prof. C. Larchet and Prof. V. Nikonenko for donating MK-40 membrane samples. Financial support from Universidad Complutense de Madrid under Project PR1/08-15918-A is also gratefully acknowledged., The aim of this work was to study the sorption and transport of different water–alcohol solutions (methanol, ethanol, 1-propanol and 2-propanol solutions) when a Nafion 117 membrane is separating them. It was observed that methanol permeability remains constant when varying the composition of the mixture. However, the permeability for the other alcohol solutions decreases from alcohol concentrations that are different for each alcohol. In addition, it was aimed to compare the behavior of membraneswith different morphologies when they were separating water and water–alcohol solutions. Nafion 117membrane and two sulfonated cation-exchange membranes (CR65-AZL-412 and MK-40) were used. Measurements of sorption and liquid transport were made using methanol and ethanol solutions. The uptake values for Nafion 117 membrane were higher than those obtained for CR65-AZL-412 and MK-40 membranes. The results reveal that, in contrast to Nafion membrane, a non-negligible water flux through CR65-AZL-412 and MK-40 membranes was observed along with the alcohol diffusion through them. For these two latter membranes the permeability could not be calculated since the alcohol diffusion is not the only physical process that should be considered. In spite of it, the alcohol and water fluxes through CR65-AZL-412 and MK-40 were estimated; turning out that the water flux was higher than alcohol flux., Universidad Complutense de Madrid, Depto. de Estructura de la Materia, Física Térmica y Electrónica, Fac. de Ciencias Físicas, TRUE, pub

© 2008 Elsevier B.V. The present work was performed at the Department of Nuclear Methods and Process Engineering, Institute of Nuclear Chemistry and Technology Warsaw and was financially supported by FP6 European Funds under Marie Curie project: AMERAC no. MTKDCT-2004-509226. The authors acknowledge this financial support., The factorial design of experiments and desirability function approach has been applied for multiresponse optimization in pervaporation separation process. Two organic aqueous solutions were considered as model mixtures, water/acetonitrile and water/ethanol mixtures. Two responses have been employed in multi-response optimization of pervaporation, total permeate flux and organic selectivity. The effects of three experimental factors (feed temperature, initial concentration of organic compound in feed solution, and downstream pressure) on the pervaporation responses have been investigated. The experiments were performed according to a 21 full factorial experimental design. The factorial models have been obtained from experimental design and validated statistically by analysis of variance (ANOVA). The spatial representations of the response functions were drawn together with the corresponding contour line plots. Factorial models have been used to develop the overall desirability function. In addition, the overlap contour plots were presented to identify the desirability zone and to determine the optimum point. The optimal operating conditions were found to be, in the case of water/acetonitrile mixture, a feed temperature of 55 degrees C, an initial concentration of 6.58% and a downstream pressure of 13.99 kPa, while for water/ethanol mixture a feed temperature of 55 degrees C, an initial concentration of 4.53% and a downstream pressure of 9.57 kPa. Under such optimum conditions it was observed experimentally an improvement of both the total permeate flux and selectivity., FP6 European Funds, Depto. de Estructura de la Materia, Física Térmica y Electrónica, Fac. de Ciencias Físicas, TRUE, pub

© Elsevier B.V. The authors gratefully acknowledge the financial support of the ""Consellería de Innovación e Industria de la Xunta de Galicia"" (project PGIDIT07PXIB310190PR), We measured using the multi-current hot-wire method the thermal conductivity (lambda) of two different clay pastes suitable to be used as peloids The same wire and system was used to measure the lambda of water and the results were compared with literature data Special attention was paid to statistical data analysis The obtained lambda values for the clay pastes are higher than the lambda of water at the same temperature., Consellería de Innovación e Industria de la Xunta de Galicia, Depto. de Estructura de la Materia, Física Térmica y Electrónica, Fac. de Ciencias Físicas, TRUE, pub

© 2005 Elsevier B.V. N.A. Zubir wishes to thank the Malaysian Ministry of Science, Technology and Innovation (MOSTI) for a fellowship awarded under the National Science Fellowship (NSF) programme. Thanks are also due to Rosiah Rohani, Tg. Ida Sofina Ngah, and Nur Amzira Sulaiman from the Membrane Research Unit, Universiti Teknologi Malaysia for their assistance in reproducing some of the membrane samples., Polymer electrolyte pore-filled membranes, for possible use in direct methanol fuel cells (DMFCs), have been prepared by radiochemical grafting of styrene into porous poly(vinylidene fluoride) (PVDF) films using simultaneous irradiation with an electron beam (EB) followed by a sulfonation reaction. The physico-chemical properties of the obtained polystyrene sulfortic acid pore-filled membranes are evaluated using Fourier transform infrared spectroscopy (FTIR), scanning electron microscopy (SEM), ac impedance, and a methanol diffusion cell. The effects of variation of the grafting yield (Y%) on the ionic conductivity and the methanol permeability of the membranes are investigated. The ionic conductivity of the membranes increases with increase in Y% and exceeds that of the perfluorinated ionomer membrane, Nafion 117, at a grafting yield of 46%. The methanol penneability of 40 and 46% pore-filled membranes is lower than that of Nation 117 by 53 and 71 %, respectively. The performance characteristic factor suggests that these membranes are potential candidates for DMFC applications., Malaysian Ministry of Science, Technology and Innovation (MOSTI), Depto. de Estructura de la Materia, Física Térmica y Electrónica, Fac. de Ciencias Físicas, TRUE, pub

© 2006 The American Physical Society., In this paper we evaluate the enhancement of nonequilibrium concentration fluctuations induced by the Soret effect when a binary fluid layer is subjected to a stationary temperature gradient. Starting from the fluctuating Boussinesq equations for a binary fluid in the large-Lewis-number approximation, we show how one can obtain an exact expression for the nonequilibrium structure factor in the long-wavelength limit for a fluid layer with realistic impermeable and no-slip boundary conditions. A numerical calculation of the wave-number dependence of the nonequilibrium enhancement and of the corresponding decay rate of the concentration fluctuations is also presented. Some physical consequences of our results are briefly discussed., Depto. de Estructura de la Materia, Física Térmica y Electrónica, Fac. de Ciencias Físicas, TRUE, pub

© 2011 Elsevier Ltd. The authors gratefully acknowledge the financial support from International Foundation of Science (Stockholm, Sweden) Grant No: W/4749-1., Olive mill wastewater (OMW) is an important environmental pollution problem, especially in the Mediterranean, which is the main olive oil production region worldwide. Environmental impact of OMW is related to its high organic load and particularly to the phytotoxic and antibacterial action of its phenolic content. In fact, polyphenols are known as powerful antioxidants with interesting nutritional and pharmaceutical properties. In the present work, the efficiency of OMIV Micellar Enhanced Ultrafiltration (MEUF) treatment for removal and concentration of polyphenols was investigated, using an anionic surfactant (Sodium Dodecyl Sulfate salt, SDS) and a hydrophobic poly(vinyldene fluoride) (PVDF) membrane. The effects of the process experimental conditions on the permeate flux were investigated, and the secondary membrane resistance created by SDS molecules was evaluated. The initial fluxes of OMW processing by MEUF using SDS were 25.7 and 44.5 l/m(2) h under transmembrane pressures of 3.5 and 4.5 bar, respectively. The rejection rate of polyphenols without using any surfactant ranged from 5 to 28%, whereas, it reached 74% when SDS was used under optimum pH (pH 2). The MEUF provides a slightly colored permeate (about 88% less dark), which requires clearly less chemical oxygen demand (COD) for its oxidation (4.33% of the initial COD). These results showed that MEUF process can efficiently be applied to the treatment of OMW and for the concentration and recovery of polyphenols., International Foundation of Science (Stockholm, Sweden), Depto. de Estructura de la Materia, Física Térmica y Electrónica, Fac. de Ciencias Físicas, TRUE, pub

© 2006 Elsevier Ltd., The sorption of water-methanol mixtures containing a dissolved chloride salt in a Nafion 117 membrane, and their transport through the membrane under the driving force of a pressure gradient, have been studied. Both type of experiments was performed by using five different salts: lithium chloride, sodium chloride, cesium chloride, magnesium chloride and calcium chloride. It was observed that both the permeation flow through the membrane and the membrane swelling increase significantly with the methanol content of the solutions. These facts are attributed to the increase in wet membrane porosity, which brings about the increase of the mobility of solvents in the membrane, besides the increase of the mobility of the polymer pendant chains. In contrast, the influence of the type of electrolyte on the membrane porosity and permeability is not very important, with the exception of the CsCl solutions, which is probably due to the small hydration ability of the Cs+ ion., Depto. de Estructura de la Materia, Física Térmica y Electrónica, Fac. de Ciencias Físicas, TRUE, pub

© 2016 Hydrogen Energy Publications. © Published by Elsevier Ltd. Financial support of this work by Banco de Santander and Universidad Complutense de Madrid within the framework of Project 910358 UCM Research Group-GR3/14 is gratefully acknowledged., Swelling properties of four commercial anion-exchange membranes with different structure have been analyzed in several hydro-organic media. With this target, the liquid uptake and the surface expansion of the membranes in contact with different pure liquids, water and alcohols (methanol, ethanol and 1-propanol), and with water alcohol mixtures with different concentrations have been experimentally determined in presence and in absence of an alkaline medium (LiOH, NaOH and KOH of different concentrations). The alkali-metal doping effect on the membrane water uptake has also been investigated, analyzing the influence of the hydroxide concentration and the presence of an alcohol in the doping solution. The results show that the membrane structure plays an essential role in the influence that alcohol nature and alkaline media has on the selective properties of the membrane. The heterogeneous membranes, with lower density, show higher liquid uptakes and dimensional changes than the homogeneous membranes, regardless of the doping conditions. (C) 2016 Hydrogen Energy Publications LLC. Published by Elsevier Ltd. All rights reserved., Banco Santander Central Hispano (BSCH), Universidad Complutense de Madrid (UCM), Depto. de Estructura de la Materia, Física Térmica y Electrónica, Fac. de Ciencias Físicas, TRUE, pub

Eco-friendly mixtures may substitute pure working fluids in thermodynamic cycle processes, yet the existing calculation approaches of mixture condensation are complex due to iterative procedures and multiple input data. To simplify condenser design, this project aims for a new calculation method of mixtures. On this behalf, experimental data for the condensation of ethanol/water and ethanol/octamethyltrisiloxane is provided within a wide composition range to identify the most influential parameters. Finally, a practical prediction method for heat transfer coefficients of mixtures is suggested.

Harnessing the potential of phase change materials can revolutionise thermal energy storage, addressing the discrepancy between energy generation and consumption. Phase change materials are renowned for their ability to absorb and release substantial heat during phase transformations and have proven invaluable in compact thermal energy storage technologies and thermal management applications. Present-day solutions mainly comprise of non-renewable phase change materials, where cyclability and sustainability concerns are increasingly being discussed. In pursuit of sustainable energy models, phase change material research has shifted towards biobased materials. This review explores the growing field of biobased phase change materials, aiming to identify prevailing trends, potential opportunities, and future applications. In addition, the persisting challenges of biobased phase change materials are discussed, where a critical dialogue on the current obstacles and research gaps is presented, offering a glimpse into the future of this rapidly evolving field. The authors furthermore present novel methods to enhance the integration of biobased phase change materials into thermal energy storage applications, ensuring their seamless adoption and maximum efficacy. With an analysis of 180 selected works, this review paints a vivid picture of the capabilities and promising prospects of biobased phase change materials, whilst highlighting the future research questions needing to be addressed., + ID der Publikation: hslu_99939 + Art des Beitrages: Wissenschaftliche Medien + Sprache: Englisch + Letzte Aktualisierung: 2024-01-15 10:44:02

Current environmental risk assessment of polluted sites primarily relies on single compound evaluation. However, in the environment, organisms are often exposed to complex mixtures of pollutants. To further develop risk assessment of polluted sites and evaluate the risks that mixtures pose to humans and wildlife, a mechanistic understanding of mixture toxicity is needed. The overall aim of this thesis was to increase our knowledge of the toxic effects caused by chemical mixtures and to develop new approaches to investigate the molecular mechanisms underlying such effects. To reach this aim, a comprehensive set of methods was applied, considering molecular and phenotypical alterations as well as chemical analyses. The investigations revealed that the acute toxicity caused by mixtures of the pollutants B[a]P, PFOS, PCB126, and Arsenate is mainly predictable by concentration addition. The results also showed some specific sublethal effects of the various mixtures that were not observed for the single components. In addition, each mixture caused very specific patterns of behavioral alterations, gene expression changes, altered lipid content, and altered organ growth. A complex environmental mixture from soil contaminated with PACs caused for instance behavioral alterations in zebrafish, in addition to dysfunction of genes that are critical for eye development. In summary, this thesis contributes to an increased understanding of the mechanistic pathways underlying the mixture toxicity of selected pollutants and environmental samples. In addition, it provides insights for the development of new approaches that may be included in risk assessment, such as image analysis and effect-directed analysis.

Effect-based methods (EBM) have great potential for water quality monitoring as they can detect the mixture effects of all active known and unknown chemicals in a sample, which cannot be addressed by chemical analysis alone. To date, EBM have primarily been applied in a research context, with a lower level of uptake by the water sector and regulators. This is partly due to concerns regarding the reliability and interpretation of EBM. Using evidence from the peer-reviewed literature, this work aims to answer frequently asked questions about EBM. The questions were identified through consultation with the water industry and regulators and cover topics related to the basis for using EBM, practical considerations regarding reliability, sampling for EBM and quality control, and what to do with the information provided by EBM. The information provided in this work aims to give confidence to regulators and the water sector to stimulate the application of EBM for water quality monitoring.

High-Content SBS Polymer Modified Asphalt Mixtures (HCPMA) combined with fibers have gained popularity in porous pavement construction due to their superior performance. Although the aging behavior of HCPMA has been extensively studied, the impact of fibers on performance and aging susceptibility remains unclear. This research investigates the influence of two representative fibers (lignin and polyester) on the raveling, cracking, fatigue, and rutting resistance of HCPMA before and after aging using Cantabro loss tests, SCB strength tests, SCB fatigue tests, and Hamburg Wheel-Tracking tests. The results indicate that in the original state, polyester fiber slightly enhances HCPMA performance, while lignin fiber shows limited or even adverse effects on cracking, raveling, fatigue, and rutting resistance. However, both fibers exhibit a more pronounced enhancement effect after short- and long-term aging. FTIR analysis reveals that fiber addition does not significantly impact bitumen oxidation and polymer degradation. The excellent properties of High-Content SBS Polymer Modified Bitumen (HCPMB) in the original state create a "masking" effect that conceals the enhancement effect of fibers, which becomes more evident after long-term aging. Consequently, it is recommended that the performance evaluation and design of open-graded asphalt mixtures containing HCPMB be based on post-aging performance., Pavement Engineering

This cross-age study aimed to provide an insight into the development of stu- dents’ understanding of the concept of matter, at the macroscopic and sub-microscopic level of chemistry knowledge. The research sample encompassed 121 students aged 14 years, 108 stu- dents aged 16 years and 112 students aged 19 years. All students completed the test comprised of five pictures and five schemata which depicted a monatomic/diatomic element, a compound and a homogeneous/heterogeneous mixture, at both of the levels. In this way, it was examined whether the selected age groups exhibit significant differences in understanding of elements, compounds and mixtures at the above-mentioned levels and whether the depth of understanding of these concepts at the macroscopic and sub-microscopic level significantly changes with the age of students. Research results indicate that all three age groups have a significantly better understanding of diatomic elements, compounds and heterogeneous mixtures at the macro- scopic, in comparison to the sub-microscopic level and a significantly better understanding of monatomic elements and homogeneous mixtures at the sub-microscopic, in comparison to the macroscopic level. Overall, a significant improvement of understanding of the concept of matter, at each of the levels, was only observed between the ages of 14 and 16.

Aminyl radicals are nitrogen-centered radicals of interest in synthetic strategies involving C–N bond formation due to their high reactivity. These intermediate radicals are generated by the reaction of an organic azide with tributyltin hydride (Bu3SnH) in the presence of substoichiometric amounts of azobisisobutyronitrile (AIBN). In this work, we report the regioselective rearrangement of azanorbornanic ([2.2.1]azabicyclic) aminyl radicals into 2,8-diazabicyclo[3.2.1]oct-2-ene systems. With the aim to establish the structural requirements for this ring expansion, we have studied the effect of different bridgehead atoms of the [2.2.1]bicyclic system and the presence of an alkyl substituent at C4. Attempts to perform this ring expansion on a monocyclic analogue have been also explored to evaluate the influence of the bicyclic skeleton on the rearrangement. A detailed mechanistic proposal supported by computational studies is reported.

Risk assessment of chemicals is still primarily focusing on single compound evaluation, even if environmental contamination consists of a mixture of pollutants. The concentration addition (CA) and independent action (IA) models have been developed to predict mixture toxicity. Both models assume no interaction between the components, resulting in an additive mixture effect. In the present study, the embryo toxicity test (OECD TG no. 236) with zebrafish embryos (Danio rerio) was performed to investigate whether the toxicity caused by binary, ternary, and quaternary mixtures of organic (Benzo[a]pyrene, perfluorooctanesulfonate, and 3,3´,4,4´,5-pentachlorobiphenyl 126) and inorganic (arsenate) pollutants can be predicted by CA and IA. The acute toxicity and sub-lethal alterations such as lack of blood circulation were investigated. The models estimated the mixture toxicity well and most of the mixtures were additive. However, the binary mixture of PFOS and PCB126 caused a synergistic effect, with almost a ten-fold difference between the observed and predicted LC50-value. For most of the mixtures, the CA model was better in predicting the mixture toxicity than the IA model, which was not expected due to the chemicals' different modes of action. In addition, some of the mixtures caused sub-lethal effects not observed in the single compound toxicity tests. The mixture of PFOS and BaP caused a division of the yolk and imbalance was caused by the combination of PFOS and As and the ternary mixture of PFOS, As, and BaP. Interestingly, PFOS was part of all three mixtures causing the mixture specific sub-lethal effects. In conclusion, the present study shows that CA and IA are mostly resulting in good estimations of the risks that mixtures with few components are posing. However, for a more reliable assessment and a better understanding of mixture toxicity, further investigations are required to study the underlying mechanisms., Funding agency:General Electric 201660019

BackgroundPrenatal exposure to individual per‑ and poly‑fluoroalkyl substances (PFAS) and psychosocial stressors have been associated with reductions in fetal growth. Studies suggest cumulative or joint effects of chemical and non-chemical stressors on fetal growth. However, few studies have examined PFAS and non-chemical stressors together as a mixture, which better reflects real life exposure patterns. We examined joint associations between PFAS, perceived stress, and depression, and fetal growth using two approaches developed for exposure mixtures.MethodsPregnant participants were enrolled in the Chemicals in Our Bodies cohort and Illinois Kids Development Study, which together make up the ECHO.CA.IL cohort. Seven PFAS were previously measured in 2nd trimester maternal serum samples and were natural log transformed for analyses. Perceived stress and depression were assessed using self-reported validated questionnaires, which were converted to t-scores using validated methods. Quantile g-computation and Bayesian kernel machine regression (BKMR) were used to assess joint associations between PFAS, perceived stress and depression t-scores and birthweight z-scores (N = 876).ResultsIndividual PFAS, depression and perceived stress t-scores were negatively correlated with birthweight z-scores. Using quantile g-computation, a simultaneous one quartile increase in all PFAS, perceived stress and depression t-scores was associated with a slight reduction in birthweight z-scores (mean change per quartile increase = -0.09, 95% confidence interval = -0.21,0.03). BKMR similarly indicated that cumulative PFAS and stress t-scores were modestly associated with lower birthweight z-scores. Across both methods, the joint association appeared to be distributed across multiple exposures rather than due to a single exposure.ConclusionsOur study is one of the first to examine the joint effects of chemical and non-chemical stressors on fetal growth using mixt

Substances of unknown or variable composition, complex reaction products, and biological materials (UVCBs) pose a unique challenge to regulators and to product registrants, who are required to characterize their fate, exposure, hazard, and potential risks to human health and the environment. To address these challenges and ensure an efficient and fit-for-purpose process, it is proposed that the ecological risks of UVCBs be assessed following a tiered strategy. The development of this approach required exploring how substance composition ties into hazard and exposure information and determining the extent to which a UVCB needs to be characterized to ensure a robust risk assessment. The present study highlights the key aspects of this new method. It presents how a tiered substance characterization approach can be integrated into broader UVCB risk-assessment schemes to encourage an examination of data needs before a full substance characterization is performed. The first tier of the characterization process, Tier 0, is a fundamental step that includes data from basic, lower-resolution compositional analyses. Tier 0 assessments can be used to inform hazard and exposure for any substance of interest. The need for more sophisticated, higher-tier characterization is determined by the level of uncertainty of the risk assessment. The next step will integrate a tiered exposure assessment into the characterization scheme featured in the present study, to create a more complete risk-assessment framework. Environ Toxicol Chem 2022;41:2649–2657. © 2022 Her Majesty the Queen in Right of Canada, Health and Environmental Sciences Institute and The Authors. Environmental Toxicology and Chemistry published by Wiley Periodicals LLC on behalf of SETAC. Reproduced with the permission of the Minister of Environment and Climate Change Canada.