Optimized Pore Nanospace through the Construction of a Cagelike Metal-Organic Framework for CO2/N2 Separation.

The development of metal-organic framework (MOF) adsorbents with a potential molecule sieving effect for CO2 capture and separation from flue gas is of critical importance for reducing the CO2 emissions to the atmosphere yet challenging. Herein, a cagelike MOF with a suitable cage window size falling between CO2 and N2 and the cavity has been constructed to evaluate its CO2/N2 separation performance. It is noteworthy that the introduction of coordinated dimethylamine (DMA) and N,N'-dimethylformamide (DMF) molecules not only significantly reduces the cage window size but also enhances the framework-CO2 interaction via C-H···O hydrogen bonds, as proven by molecular modeling, thus leading to an improved CO2 separation performance. Moreover, transient breakthrough experiments corroborate the efficient CO2/N2 separation, revealing that the introduction of DMA and DMF molecules plays a vital role in the separation of a CO2/N2 gas mixture.

Self-regulation mechanism difference of Chlorella vulgaris and Scenedesmus obliquus in toxic sludge extract caused by hydroquinone biodegradation.

Chlorella vulgaris (C. vulgaris) and Scenedesmus obliquus (S. obliquus) were compared to remove toxicity under conditions of sludge extract cultivation for 30 days. The toxicity of sludge extract, the growth characteristics, photosynthetic pigment, superoxide dismutase (SOD) enzyme and catalase (CAT) enzyme activities of the two microalgae were studied by contrast. The results showed that small molecular organic matter (<500 Da) was more easily utilized by microalgae. The toxicity in the toxic group of C. vulgaris and S. obliquus on the 30th day decreased to 56.8 ± 1.2% and 60.7 ± 2.8%, respectively. In the toxic group, the maximal SOD enzyme activity of C. vulgaris and S. obliquus were 2.02 U/mg proteins and 8.21 U/mg proteins, respectively, demonstrating that toxicity caused more oxidative damage to S. obliquus than to C. vulgaris. Proteomics analysis revealed that C. vulgaris mainly regulates energy synthesis and distribution primarily through sugar metabolism, and biomass synthesis primarily through carbon metabolism, whereas S. obliquus mainly regulates energy synthesis and distribution primarily through sugar metabolism and oxidative phosphorylation, resulting in sludge toxicity stress regulation.

Exposure to bisphenols and asthma morbidity among low-income urban children with asthma.

BACKGROUND: Bisphenol A (BPA) has been linked with pediatric asthma development and allergic airway inflammation in animal models. Whether exposure to BPA or its structural analogs bisphenol S (BPS) and bisphenol F (BPF) is associated with asthma morbidity remains unknown. OBJECTIVE: We examined associations between bisphenols and morbidity due to pediatric asthma. METHODS: We quantified concentrations of BPA, BPS, and BPF in 660 urine samples from 148 predominantly low-income, African American children (aged 5-17 years) with established asthma. We used biobanked biospecimens and data on symptoms, health care utilization, and pulmonary function and inflammation that were collected every 3 months over the course of a year. We used generalized estimating equations to examine associations between concentrations or detection of urinary bisphenols and morbidity outcomes and assessed heterogeneity of associations by sex. RESULTS: We observed consistent positive associations between BPA exposure and measures of asthma morbidity. For example, we observed increased odds of general symptom days (adjusted odds ratio [aOR] = 1.40 [95% C = 1.02-1.92]), maximal symptom days (aOR = 1.36 [95% CI = 1.00-1.83]), and emergency department visits (aOR = 2.12 [95% CI =1.28-3.51]) per 10-fold increase in BPA concentration. We also observed evidence of sexually dimorphic effects; BPA concentrations were associated with increased odds of symptom days and health care utilization only among boys. Findings regarding BPS and BPF did not consistently point to associations with asthma symptoms or health care utilization. CONCLUSION: We found evidence to suggest that BPA exposure in a predominantly low-income, minority pediatric cohort is associated with asthma morbidity and that associations may differ by sex. Our findings support additional studies, given the high pediatric asthma burden and widespread exposure to BPA in the United States.

Adaptive Fixed-Time Control of Strict-Feedback High-Order Nonlinear Systems.

This paper examines the adaptive control of high-order nonlinear systems with strict-feedback form. An adaptive fixed-time control scheme is designed for nonlinear systems with unknown uncertainties. In the design process of a backstepping controller, the Lyapunov function, an effective controller, and adaptive law are constructed. Combined with the fixed-time Lyapunov stability criterion, it is proved that the proposed control scheme can ensure the stability of the error system in finite time, and the convergence time is independent of the initial condition. Finally, simulation results verify the effectiveness of the proposed control strategy.

Mo2N-Ni/NF Heterostructure Boosts Electrocatalytic Hydrogen Evolution with Pt-Like Activity.

The sustainable development of a hydrogen economy requires hydrogen production from water electrolysis at a low cost, but the limited production of active and robust electrocatalysts using materials that are abundant on earth has restrained development. This article reports a heterostructure of a Mo2N phase and metal Ni nanocrystals and its activities in the hydrogen evolution reaction (HER) in alkaline electrolytes. Hydrogen is produced by the catalyst in alkaline electrolytes at a density of 10 mA cm-2 at an overpotential of only 20 mV with a small Tafel slope of 39.9 mV dec-1, in which the catalyst exhibits a synergetic effect of compact Mo2N and Ni interfacial connections, producing localized hotspots that accelerate water dissociation and hydrogen desorption. This makes the catalyst one of the most effective Pt-free species. Experimental and DFT theoretical results show that the exceptional HER electrocatalytic activity produced by the Mo2N-Ni/NF heterogeneous structure is related to the unique highly unshielded structure and high intrinsic activity accompanied by a nearly thermoneutral H-adsorption energy.

An Empirical Validation of the Within-subject Biospecimens Pooling Approach to Minimize Exposure Misclassification in Biomarker-based Studies.

BACKGROUND: Within-subject biospecimens pooling can theoretically reduce bias in dose-response functions from biomarker-based studies when exposure assessment suffers from classical-type error. However, collecting many urine voids each day is cumbersome. We evaluated the empirical validity of a within-subject pooling approach and compared several options to avoid sampling each void. METHODS: In 16 pregnant women who collected a spot of each urine void over several nonconsecutive weeks, we compared concentrations of 10 phenols in daily, weekly, and pregnancy within-subject pools. We pooled either three or all daily samples. In a simulation study using these data, we quantified bias in dose-response functions when using one to 20 urine samples per subject to assess methylparaben (a compound with moderate within-subject variability) and bisphenol A (high variability) exposures. RESULTS: Correlations between exposure estimates from pools of all and of only three voids per day were above 0.80 for all time windows and compounds, except for benzophenone-3 and triclosan in the daily time window (correlations, 0.57-0.68). With one spot sample to assess pregnancy exposure, correlations were all below 0.74. Using only one biospecimen led to attenuation bias in the dose-response functions of 29% (methylparaben) and 69% (bisphenol A); four samples for methylparaben and 18 for bisphenol A decreased bias to 10%. CONCLUSIONS: For nonpersistent chemicals, collecting and pooling three samples per day instead of all daily samples efficiently estimates exposures over a week or more. Collecting around 20 biospecimens can strongly limit attenuation bias for nonpersistent chemicals such as bisphenol A.

Association of phthalates, parabens and phenols found in personal care products with pubertal timing in girls and boys.

STUDY QUESTION: Are in-utero or peripubertal exposures to phthalates, parabens and other phenols found in personal care products associated with timing of pubertal onset in boys and girls? SUMMARY ANSWER: We found some associations of altered pubertal timing in girls, but little evidence in boys. WHAT IS KNOWN ALREADY: Certain chemicals in personal care and consumer products, including low molecular weight phthalates, parabens and phenols, or their precursors, are associated with altered pubertal timing in animal studies. STUDY DESIGN, SIZE, DURATION: Data were from the Center for the Health Assessment of Mothers and Children of Salinas (CHAMACOS) longitudinal cohort study which followed 338 children in the Salinas Valley, California, from before birth to adolescence. PARTICIPANTS/MATERIALS, SETTING, METHODS: Pregnant women were enrolled in 1999-2000. Mothers were mostly Latina, living below the federal poverty threshold and without a high school diploma. We measured concentrations of three phthalate metabolites (monoethyl phthalate [MEP], mono-n-butyl phthalate and mono-isobutyl phthalate), methyl and propyl paraben and four other phenols (triclosan, benzophenone-3 and 2,4- and 2,5-dichlorophenol) in urine collected from mothers during pregnancy and from children at age 9. Pubertal timing was assessed among 179 girls and 159 boys every 9 months between ages 9 and 13 using clinical Tanner staging. Accelerated failure time models were used to obtain mean shifts of pubertal timing associated with concentrations of prenatal and peripubertal biomarkers. MAIN RESULTS AND THE ROLE OF CHANCE: In girls, we observed earlier onset of pubic hair development with prenatal urinary MEP concentrations and earlier menarche with prenatal triclosan and 2,4-dichlorophenol concentrations. Regarding peripubertal biomarkers, we observed: earlier breast development, pubic hair development and menarche with methyl paraben; earlier menarche with propyl paraben; and later pubic hair development with 2,5-dichlorophenol. In boys, we observed no associations with prenatal urinary biomarker concentrations and only one association with peripubertal concentrations: earlier genital development with propyl paraben. LIMITATIONS, REASONS FOR CAUTION: These chemicals are quickly metabolized and one to two urinary measurements per developmental point may not accurately reflect usual exposure. Associations of peripubertal measurements with parabens may reflect reverse causality: children going through puberty early may be more likely to use personal care products. The study population was limited to Latino children of low socioeconomic status living in a farmworker community and may not be widely generalizable. WIDER IMPLICATIONS OF THE FINDINGS: This study contributes to a growing literature that suggests that exposure to certain endocrine disrupting chemicals may impact timing of puberty in children. STUDY FUNDING/COMPETING INTEREST(S): This study was funded by the National Institute of Environmental Health Sciences and the US Environmental Protection Agency. The authors declare no conflicts of interest. TRIAL REGISTRATION NUMBER: N/A.

Urinary concentrations of parabens mixture and pregnancy glucose levels among women from a fertility clinic.

BACKGROUND: A number of endocrine disrupting chemicals (EDC) have been associated with gestational diabetes (GDM) risk factors. However, no human study has investigated the association between pregnancy exposure to parabens, a class of EDCs, and pregnancy glucose levels, a risk factor for GDM. Furthermore, little is known about this association in subfertile women-a group at high risk of GDM. METHODS: A total of 241 women from the Environment and Reproductive Health Study had data available on 1st and/or 2nd trimester urinary methylparaben, propylparaben, and butylparaben concentrations, and blood glucose levels after the glucose loading test (GLT), a non-fasting 50 g glucose loading test taken at late 2nd trimester. Trimester-specific associations between specific gravity adjusted methylparaben, butylparaben, and propylparaben with adjusted mean of pregnancy glucose levels were evaluated in linear regression models, using quartiles of each paraben's distribution, and as a paraben mixture, using mutual adjustment and Bayesian kernel machine regression (BKMR), a recently proposed method for investigating chemical mixtures that flexibly models the joint effect of chemicals. RESULTS: Investigating parabens one at the time did not provide any significant results. When investigating parabens as a chemical mixture with both multiple regression and BKMR, we observed positive associations of butylparaben (e.g comparing the 4th and 1st quartiles) with glucose levels, for both the 1st trimester (adjusted difference=12.5 mg/dL; 95% CI: 0.9, 24.2) and 2nd trimester (adjusted difference=11.2 mg/dL; 95% CI: 0.2, 22.3), and a negative association between 1st trimester propylparaben and glucose (adjusted difference=-22.3 mg/dL; 95% CI: -43.2, -1.4). CONCLUSIONS: We found 1st trimester butylparaben and propylparaben urinary concentrations to be associated with glucose levels in a pregnancy cohort of women at high risk of GDM, even after adjusting for potential confounders. Because exposure to parabens is widespread, these findings may suggest further investigating the effects of this chemical class on pregnancy health.

Prenatal and early-life triclosan and paraben exposure and allergic outcomes.

BACKGROUND: In cross-sectional studies triclosan and parabens, ubiquitous ingredients in personal care and other products, are associated with allergic disease. OBJECTIVES: We investigated the association between prenatal and early-life triclosan and paraben exposure and childhood allergic disease in a prospective longitudinal study. METHODS: Subjects were enrollees in the Vitamin D Antenatal Asthma Reduction Trial. Triclosan, methyl paraben, and propyl paraben concentrations were quantified in maternal plasma samples pooled from the first and third trimesters and urine samples from children at age 3 or 4 years. Outcomes were parental report of physician-diagnosed asthma or recurrent wheezing and allergic sensitization to food or environmental antigens based on serum specific IgE levels at age 3 years in high-risk children. RESULTS: The analysis included 467 mother-child pairs. Overall, there were no statistically significant associations of maternal plasma or child urine triclosan or paraben concentrations with asthma or recurrent wheeze or food or environmental sensitization at age 3 years. A trend toward an inverse association between triclosan and paraben exposure and allergic sensitization was observed. There was evidence of effect measure modification by sex, with higher odds of environmental sensitization associated with increasing paraben concentrations in male compared with female subjects. CONCLUSIONS: We did not identify a consistent association between prenatal and early-life triclosan or paraben concentrations and childhood asthma, recurrent wheeze, or allergic sensitization in the overall study population. The differential effects of triclosan or paraben exposure on allergic sensitization by sex observed in this study warrant further exploration.

[Effects of triptolide on the activity of TM3 Leydig cells and AMPK/Akt/mTOR pathway].

OBJECTIVE: To investigate the effects of triptolide (TP) on the activity of TM3 Leydig cells and the AMPK/Akt/mTOR pathway. METHODS: We treated TM3 Leydig cells with TP at 50, 100 and 200 nmol/L, respectively, and with 0.1% DMSO as the control, and cultured them in a 37℃ thermostat container for 24 hours. Then we measured the damage to the cell membrane and apoptosis of the cells using lactate dehydrogenase (LDH) activity assay and the apoptosis assay kit, and detected the changes in the AMPK/Akt/mTOR pathway-related proteins by Western blot. RESULTS: The LDH activity was significantly increased in the 50, 100 and 200 nmol/L TP groups in a dose-dependent manner compared with that in the DMSO control (ï¼»163.4±33.6ï¼½%, ï¼»346.8±148.8ï¼½% and ï¼»422.8±113.9ï¼½% vs ï¼»157.5±20.3ï¼½%, P < 0.01), and so was the apoptosis of the cells (ï¼»189.9±73.5ï¼½%, ï¼»284±103.5ï¼½% and ï¼»419.2±155.7ï¼½% vs ï¼»6.27±1.41ï¼½%, P < 0.01). The TP-treated cells showed a significantly decreased p-AMPK/AMPK ratio in comparison with the control (P < 0.01), but an increased p-Akt/Akt ratio (P < 0.05) and an elevated level of p-mTOR phosphorylation (P < 0.05). CONCLUSIONS: Triptolide can decrease the activity and induce the apoptosis of TM3 Leydig cells, and meanwhile inhibit the AMPK and activate the Akt/mTOR pathway.

Early-Pregnancy Plasma Concentrations of Perfluoroalkyl Substances and Birth Outcomes in Project Viva: Confounded by Pregnancy Hemodynamics?

Associations of prenatal exposure to perfluoroalkyl substances (PFAS), ubiquitous chemicals used in stain- and water-resistant products, with adverse birth outcomes may be confounded by pregnancy hemodynamics. We measured plasma concentrations of 4 PFAS in early pregnancy (median length of gestation, 9 weeks) among 1,645 women in Project Viva, a study of a birth cohort recruited during 1999-2002 in eastern Massachusetts. We fitted multivariable models to estimate associations of PFAS with birth weight-for-gestational age z score and length of gestation, adjusting for sociodemographic confounders and 2 hemodynamic markers: 1) plasma albumin concentration, a measure of plasma volume expansion, and 2) plasma creatinine concentration, used to estimate glomerular filtration rate. Perfluorooctane sulfonate (PFOS) and perfluorononanoate (PFNA) were weakly inversely associated with birth weight-for-gestational age z scores (adjusted ß = -0.04 (95% confidence interval (CI): -0.08, 0.01) and adjusted ß = -0.06 (95% CI: -0.11, -0.01) per interquartile-range increase, respectively). PFOS and PFNA were also associated with higher odds of preterm birth (e.g., for highest PFOS quartile vs. lowest, adjusted odds ratio = 2.4, 95% CI: 1.3, 4.4). Adjusting for markers of pregnancy hemodynamics (glomerular filtration rate and plasma albumin), to the extent that they accurately reflect underlying pregnancy physiology, did not materially affect associations. These results suggest that pregnancy hemodynamics may not confound associations with birth outcomes when PFAS are measured early in pregnancy.

Distribution and predictors of urinary concentrations of phthalate metabolites and phenols among pregnant women in the Healthy Start Study.

BACKGROUND: Phthalates and phenols are suspected endocrine disrupting chemicals that may adversely impact fetal outcomes following in utero exposure. Understanding predictors of exposure to phthalates and phenols during the prenatal period is important. METHODS: We measured urinary concentrations of 15 phthalate metabolites and 11 phenols in 446 pregnant women enrolled in the Healthy Start pre-birth cohort. Creatinine-adjusted geometric means (GM) for each urinary biomarker were compared across categories of potential sociodemographic and dietary predictors. To assess the independent relationship between each significant food group predictor and biomarker we used multivariable models, adjusted for sociodemographic predictors. RESULTS: The phthalate metabolites with the highest concentrations were monoethyl phthalate (GM: 41.1µg/g creatinine) and monocarboxyisooctyl phthalate (GM: 20.5µg/g creatinine). Benzophenone-3 (GM: 124.6µg/g creatinine) and methyl paraben (GM: 119.9µg/g creatinine) were the phenols with the highest concentrations. Concentrations of the metabolites of di-n-butyl phthalate and di(2-ethylhexyl) phthalate were significantly higher in younger, unmarried or unemployed mothers, those who were overweight or obese, those with lower educational attainment, or those of minority race/ethnicity (p-values < 0.05). Metabolites of di-n-butyl phthalate concentrations were 18% lower in those who consumed milk ≥ 7 times per week (95% CI: 30-4%). Benzophenone-3 and triclosan concentrations were significantly higher in older, married, or employed mothers, those with normal body mass index, higher educational attainment, higher household income, or who were non-Hispanic white (p-values < 0.05). Benzophenone-3 concentrations were 62% higher in those who consumed seafood ≥ 5 times per month (95% CI: 16-127%). CONCLUSIONS: We observed differences in urinary concentrations of phthalates and phenol biomarkers by sociodemographic predictors in an ethnically diverse cohort of pregnant women. These results and future analyses from this prospective cohort will help inform targeted interventions to reduce exposure to these potential endocrine disrupting chemicals during pregnancy.

Associations of maternal exposure to triclosan, parabens, and other phenols with prenatal maternal and neonatal thyroid hormone levels.

Environmental phenols and parabens are commonly used in personal care products and other consumer products and human exposure to these chemicals is widespread. Although human and animal studies suggest an association between exposure to phenols and parabens and thyroid hormone levels, few studies have investigated the association of in utero exposure to these chemicals and thyroid hormones in pregnant women and their neonates. We measured four environmental phenols (triclosan, benzophenone-3, and 2,4- and 2,5-dichlorophenol), and three parabens (methyl-, propyl-, and butyl paraben) in urine collected from mothers at two time points during pregnancy as part of the CHAMACOS (Center for the Health Assessment of Mothers and Children of Salinas) study. We measured free thyroxine (T4), total T4, and thyroid-stimulating hormone (TSH) in serum of the pregnant women (N = 454) and TSH in their neonates (N = 365). We examined potential confounding by a large number of additional chemical exposures and used Bayesian Model Averaging (BMA) to select the most influential chemicals to include in regression models. We observed negative associations of prenatal urinary concentrations of propyl paraben and maternal TSH (ß for two-fold increase = -3.26%, 95% CI: -5.55, -0.90) and negative associations of 2,4-dichlorophenol and maternal free T4 (ß for two-fold increase = -0.05, 95% CI: -0.08, -0.02), after controlling for other chemical exposures. We observed negative associations of triclosan with maternal total T4 after controlling for demographic variables, but this association became non-significant after controlling for other chemicals (ß for two-fold increase = -0.05, 95% CI: -0.11, 0.00). We found evidence that environmental phenols and parabens are associated with lower TSH and free T4 in pregnant women after controlling for related chemical exposures.

Childhood and adolescent phenol and phthalate exposure and the age of menarche in Latina girls.

BACKGROUND: The age of menarche has been associated with metabolic and cardiovascular disease, as well as cancer risk. The decline in menarcheal age over the past century may be partially attributable to increased exposure to endocrine disrupting chemicals (EDCs). METHODS: We assessed the influence of 26 phenol and phthalate biomarkers on the timing of menarche in a longitudinal cohort of Chilean girls. These EDCs were quantified in urine collected prior to the onset of breast development (Tanner 1; B1), and during adolescence (Tanner 4; B4). Multivariable accelerated failure time (AFT) models were used to analyze associations between biomarker concentrations and the age of menarche adjusting for body mass index (BMI) Z-score and maternal education, accounting for within-subject correlation. RESULTS: Several biomarkers were significantly associated with the age at menarche; however, these associations were dependent on the timing of biomarker assessment. A log(ng/ml) increase in B1 concentrations of di(2-ethylhexyl) phthalate biomarkers was associated with later menarche (hazard ratio (HR): 0.77; 95% CI: 0.60, 0.98), whereas higher B1 concentrations of 2,5-dichlorophenol and benzophenone-3 were associated with earlier menarche (HR: 1.13; 95% CI: 1.01, 1.27; HR: 1.17; 95% CI: 1.06, 1.29, respectively). Elevated B4 concentrations of monomethyl phthalate were similarly associated with earlier menarche (HR: 1.30; 95% CI: 1.10, 1.53). The impact of monoethyl phthalate and triclosan concentrations on pubertal timing were significantly modified by BMI Z-score. Higher monoethyl phthalate and triclosan concentrations were associated with earlier menarche among overweight or obese girls, but not among those that were normal weight. CONCLUSIONS: This study identifies modulation of sexual maturation by specific EDC biomarkers in Latina girls.

Trimester-specific phthalate concentrations and glucose levels among women from a fertility clinic.

BACKGROUND: Subfertile women are at increased risk of glucose intolerance in pregnancy. Based on epidemiologic studies, exposure to certain phthalates is associated with diabetes, elevated glucose, and increased insulin resistance. OBJECTIVES: To evaluate the association between urinary phthalate metabolites and pregnancy glucose levels in women seeking medically assisted reproduction. METHODS: We evaluated 245 women participating in a prospective cohort study based at a large fertility clinic who delivered live births and had data on pregnancy urinary phthalate metabolite concentrations and blood glucose levels. Urinary phthalate metabolite concentrations were from single spot urine samples collected in 1st and 2nd trimesters. Blood glucose data was abstracted from medical records for non-fasting 50-g glucose challenge tests at 24-28 weeks gestation. Multivariable linear regression models were used to evaluate associations between 7 urinary phthalate metabolites in quartiles and mean glucose adjusted for potential confounders. RESULTS: Eighteen percent of women had glucose levels ≥ 140 mg/dL. Second trimester monoethyl phthalate (MEP) concentrations were positively associated with glucose levels, with adjusted mean (95%CI) glucose levels of 121 mg/dl (114, 128) vs. 109 mg/dL (103, 116) for women in highest and lowest quartiles, respectively. Women in the highest quartile of second trimester mono-isobutyl phthalate (MiBP) concentrations had a mean glucose level 14 mg/dL lower compared to women in the lowest quartile. No other urinary phthalate metabolites were associated with glucose levels. CONCLUSIONS: MEP and MiBP-metabolites of diethyl phthalate and dibutyl phthalate, respectively-were associated with higher pregnancy glucose in subfertile women-a population at high risk of glucose intolerance in pregnancy.

Cumulative exposure to environmental pollutants during early pregnancy and reduced fetal growth: the Project Viva cohort.

BACKGROUND: Reduced fetal growth is associated with perinatal and later morbidity. Prenatal exposure to environmental pollutants is linked to reduced fetal growth at birth, but the impact of concomitant exposure to multiple pollutants is unclear. The purpose of this study was to examine interactions between early pregnancy exposure to cigarette smoke, traffic pollution, and select perfluoroalkyl substances (PFASs) on birth weight-for-gestational age (BW/GA). METHODS: Among 1597 Project Viva mother-infant pairs, we assessed maternal cigarette smoking by questionnaire, traffic pollution at residential address by black carbon land use regression model, and plasma concentration of select PFASs in early pregnancy. We calculated sex-specific BW/GA z-scores, an index of fetal growth, from national reference data. We fit covariate-adjusted multi-pollutant linear regression models and examined interactions between exposures, using a likelihood-ratio test to identify a best-fit model. RESULTS: Two hundred six (13%) mothers smoked during pregnancy. Mean [standard deviation (SD)] for black carbon was 0.8 (0.3) µg/m3, perfluorooctane sulfonate (PFOS) was 29.1 (16.5) ng/mL, and BW/GA z-score was 0.19 (0.96). In the best-fit model, BW/GA z-score was lower in infants of mothers exposed to greater black carbon [- 0.08 (95% CI: -0.15, - 0.01) per interquartile range (IQR)]. BW/GA z-score (95% CI) was also lower in infants of mothers who smoked [- 0.09 (- 0.23, 0.06)] or were exposed to greater PFOS [- 0.03 (- 0.07, 0.02) per IQR], although confidence intervals crossed the null. There were no interactions between exposures. In secondary analyses, instead of PFOS, we examined perfluorononanoate (PFNA) [mean (SD): 0.7 (0.4) ng/mL], a PFAS more closely linked to lower BW/GA in our cohort. The best-fit multi-pollutant model included positive two-way interactions between PFNA and both black carbon and smoking (p-interactions = 0.03). CONCLUSIONS: Concurrent prenatal exposures to maternal smoking, black carbon, and PFOS are additively associated with lower fetal growth, whereas PFNA may attenuate associations of smoking and black carbon with lower fetal growth. It is important to examine interactions between multiple exposures in relation to health outcomes, as effects may not always be additive and may shed light on biological pathways.

Patterns, Variability, and Predictors of Urinary Triclosan Concentrations during Pregnancy and Childhood.

Exposure to triclosan, an antimicrobial used in many consumer products, is ubiquitous in the United States, yet only limited data are available on the predictors and variability of exposure, particularly in children. We examined the patterns, variability, and predictors of urinary triclosan concentrations in 389 mother-child pairs enrolled in the Health Outcomes and Measures of the Environment Study from 2003 to 2006. We quantified triclosan in 3 urine samples collected from women between 16 weeks of pregnancy and birth and 6 urine samples collected from children between the ages of 1-8 years. For maternal and child samples, we calculated intraclass correlation coefficients (ICCs) to assess triclosan reproducibility and identified sociodemographic predictors of triclosan. Among 8 year old children, we examined associations between triclosan and personal-care product use. We detected triclosan in >70% of urine samples. Median maternal triclosan varied across pregnancy from 17 to 11 ng/mL, while in children, median concentrations increased from 3.6 to 17 ng/mL over the first 4 years of life, declining slightly at later ages. Triclosan reproducibility was fair to good during pregnancy and for child samples taken weeks apart (ICCs = 0.4-0.6) but poor for annual child samples (ICCs = 0.2-0.4). Triclosan was 66% (95% CI: 29-113) higher in 8 year olds using hand soap compared to nonusers and increased monotonically with hand-washing frequency. Toothpaste use in children was also positively associated with triclosan. Our results suggest that urinary triclosan concentrations have modest stability over weeks to months; children are exposed to triclosan through the use of some personal-care products.

Predictors of Per- and Polyfluoroalkyl Substance (PFAS) Plasma Concentrations in 6-10 Year Old American Children.

Certain per- and polyfluoroalkyl substances (PFASs) are suspected developmental toxicants, but data on PFAS concentrations and exposure routes in children are limited. We measured plasma PFASs in children aged 6-10 years from the Boston-area Project Viva prebirth cohort, and used multivariable linear regression to estimate associations with sociodemographic, behavioral, and health-related factors, and maternal PFASs measured during pregnancy. PFAS concentrations in Project Viva children (sampled 2007-2010) were similar to concentrations among youth participants (aged 12-19 years) in the 2007-8 and 2009-10 National Health and Nutrition Examination Survey (NHANES); mean concentrations of most PFASs declined from 2007 to 2010 in Project Viva and NHANES. In mutually adjusted models, predictors of higher PFAS concentrations included older child age, lower adiposity, carpeting or a rug in the child's bedroom, higher maternal education, and higher neighborhood income. Concentrations of perfluorooctanesulfonate (PFOS), perfluorooctanoate (PFOA), perfluorohexanesulfonate (PFHxS), and 2-(N-methyl-perfluorooctane sulfonamido) acetate (Me-PFOSA-AcOH) were 26-36% lower in children of black mothers compared to children of white mothers and increased 12-21% per interquartile range increase in maternal pregnancy PFASs. Breastfeeding duration did not predict childhood PFAS concentrations in adjusted multivariable models. Together, the studied predictors explained the observed variability in PFAS concentrations to only a modest degree.

Quantification of urinary mono-hydroxylated metabolites of polycyclic aromatic hydrocarbons by on-line solid phase extraction-high performance liquid chromatography-tandem mass spectrometry.

Human exposure to polycyclic aromatic hydrocarbons (PAHs) can be assessed through monitoring of urinary mono-hydroxylated PAHs (OH-PAHs). Gas chromatography (GC) has been widely used to separate OH-PAHs before quantification by mass spectrometry in biomonitoring studies. However, because GC requires derivatization, it can be time consuming. We developed an on-line solid phase extraction coupled to isotope dilution-high performance liquid chromatography-tandem mass spectrometry (on-line-SPE-HPLC-MS/MS) method for the quantification in urine of 1-OH-naphthalene, 2-OH-naphthalene, 2-OH-fluorene, 3-OH-fluorene, 1-OH-phenanthrene, the sum of 2-OH and 3-OH-phenanthrene, 4-OH-phenanthrene, and 1-OH-pyrene. The method, which employed a 96-well plate platform and on-line SPE, showed good sensitivity (i.e., limits of detection ranged from 0.007 to 0.09 ng/mL) and used only 100 µL of urine. Accuracy, calculated from the recovery percentage at three spiking levels, varied from 94 to 113 %, depending on the analyte. The inter- and intra-day precision, calculated from 20 repeated measurements of two quality control materials, varied from 5.2 to 16.7 %. Adequate method performance was also confirmed by acceptable recovery (83-102 %) of two NIST standard reference materials (3672 and 3673). This high-throughput on-line-SPE-HPLC-MS/MS method can be applied in large-scale epidemiological studies. Graphical abstract Example LC-MS chromatogram of urinary mono-hydroxylated PAH metabolites.

Urinary triclosan concentrations during pregnancy and birth outcomes.

BACKGROUND: Triclosan is an antimicrobial chemical used in consumer products, and exposure is ubiquitous among pregnant women in the United States. Triclosan may reduce the levels of thyroid hormones that are important for fetal growth and development. OBJECTIVE: We investigated the relationship of prenatal triclosan exposure with birth anthropometry and gestational duration. METHODS: We used data from 378 mother-child pairs participating in the Health Outcomes and Measures of the Environment (HOME) Study, a prospective pregnancy and birth cohort from Cincinnati, OH. We measured triclosan concentrations in maternal urine samples collected at 16 and 26 weeks of pregnancy. We abstracted information on neonatal anthropometry and gestational duration from medical records. We used multivariable linear regression to estimate the covariate-adjusted association between the average of the two urinary triclosan concentrations and gestational age standardized weight z-score, length, head circumference, and gestational age at birth. RESULTS: Median urinary triclosan concentrations were 16ng/mL (range: <2.4 to 1501ng/mL). Each 10-fold increase in triclosan was associated with a predicted 0.15 standard deviation decrease (95% CI: -0.30, 0.00) in birth weight z-score, 0.4-cm decrease (95% CI: -0.8, 0.1) in birth length, 0.3-cm decrease (95% CI: -0.5, 0.0) in head circumference, and 0.3-week decrease (95% CI: -0.6, -0.1) in gestational age. Child sex did not modify the associations between triclosan and birth outcomes. CONCLUSIONS: In this cohort, maternal urinary triclosan concentrations during pregnancy were inversely associated with infants' birth weight, length, head circumference, and gestational age.