Dibutyl Phosphate Research Articles

Associations between organophosphate esters concentrations and markers of liver function in US adolescents aged 12–19 years: A mixture analysis

Liver disease has become a growing health burden, and little is known about the impairment of liver function caused by exposure to organophosphate esters (OPEs) in adolescents aged 12–19 years in the United States. To investigate the relationship between urinary metabolites of OPEs including diphenyl phosphate (DPHP), bis(1,3-dichloro-2-propyl) phosphate (BDCPP), bis(1-chloroethyl) phosphate (BCPP), bis(2-chloroethyl) phosphate (BCEP), and dibutyl phosphate (DBUP) and liver function in US adolescents aged 12–19 years. Liver function tests (LFTs) include aspartate aminotransferase (AST), albumin (ALB), alanine aminotransferase (ALT), alkaline phosphatase (ALP), gamma-glutamyl transferase (GGT), total bilirubin (TBIL), total protein (TP), and AST/ALT. Meanwhile, potential confounding and interaction effects were assessed. The study sample included 592 adolescents aged 12–19 from two consecutive NHANES cycles (2011–2012, 2013–2014). A composite statistical strategy combining traditional linear regression with advanced multi-pollutant models quantile based g-computation (QGC) and eXtreme Gradient Boosting (XGBoost) regression was used to analyze the joint effects of multiple OPEs on liver function indicators, and to describe the interaction between different OPEs in detail. 592 adolescent participants were 15 (14–17) years old, with similar numbers of males and females (304 vs. 288). The analysis results showed that (1) in the linear regression model, individual DPHP, BCEP exposure and ALP changes, BCEP and AST/ALT changes were positively associated. DPHP, BDCPP were negatively associated with TP changes. (2) The combined effects of various OPEs on ALB, ALT, ALP, GGT, TBIL, TP, and AST/ALT were statistically significant. (3) There is no potential interaction between different OPEs. Several OPEs and their combinations are closely related to the 8 LFT indicators. In addition, data suggest that exposure to OPEs in adolescents may be associated with liver damage. Due to limited evidence in the literature and potential limitations of the current study, our findings require more studies to confirm.

Organophosphate ester flame retardant exposure and perinatal outcomes

Background and Aims: Following a phase out of PBDE flame retardants in the mid-2000s due to concerns about toxicity, exposure to organophosphate ester (OPFRs) flame retardants increased, leading to increasing concerns regarding the toxicity of OPFRs. We hypothesize that prenatal exposure to OPFRs adversely affects outcomes at birth. Our overarching hypothesis is that prenatal exposure to OPFRs flame retardant chemicals adversely affects outcomes at birth. We propose to quantify prenatal exposure to a suite of flame retardants utilizing maternal urine collected during pregnancy to address our specific aims: 1) examine exposure trends over calendar time, and 2) investigate associations with perinatal outcomes, specifically low birth weight, preterm birth, and small for gestational age. Methods: We quantify prenatal exposure utilizing a single maternal urine collected during pregnancy, quantifying 9 OPFRs: Dipropyl phosphate (DPRP), Dibutyl phosphate + Di-isobutyl phosphate (DBUP_DIBP), bis(butoxyethyl) phosphate (BBOEP), bis(2-ethylhexyl) phosphate (BEHP), Bis(2-chlorethyl) phosphate (BCETP), Bis(1-chloro-2-propyl) phosphate (BCPP), Bis(1,3-dichloro-2-propyl) phosphate (BDCPP), Diphenyl phosphate (DPHP), and bis(2-methylphenyl) phosphate (BMPP). The study sample includes over 7000 pregnancies from 19 ECHO cohorts over 9 states. Outcomes include gestational age (continuous and categorized to consider preterm birth), birth weight (continuous and categorized to consider low birth weight), birthweight for gestational age (continuous and categorized to consider small for gestational age). Key confounders expected to be associated with both exposures and outcomes based on prior literature include cohort, maternal age, socioeconomic status (measured by education, marital status, income, or related variables), race/ethnicity, BMI, and year of birth. Results: The following compounds were detected in over 85% of the samples: BDCPP, DBUP_DIBP, and DPHP, while BBOEP, BCETP, and BCPP were detected in over 50% of samples. DPHP had the highest geometric mean concentration of 1.0 ng/mL, followed by BDCPP (0.86 ng/mL). Analysis of associations between exposures and outcomes is underway.

Association between organophosphorus flame retardants exposure and cognitive impairment among elderly population in southern China

The wide application of organophosphorus flame retardants (OPFRs) in consumer products leads to their ubiquitous occurrence. The neurotoxicity of OPFRs has been raised, whereas evidence from the elderly population were rather scarce. Hence, a case-control study was conducted based on the Shenzhen Aging-related Disorder Cohort. A total of 184 cases [Mini-mental State Examination (MMSE) < 24] and 795 participants as controls (MMSE ≥24) were recruited. Eight metabolites of OPFRs (m-OPFRs) in urine samples were measured, including bis(2-butoxyethyl) phosphate (BBOEP), bis(2-chloroethyl) phosphate (BCEP), bis(1-chloro-2-propyl) phosphate (BCIPP), bis(1,3-dichloro-2-propyl) phosphate (BDCIPP), dibutyl phosphate (DBP), di-o-cresyl phosphate (DOCP), di-p-cresyl phosphate (DPCP) and diphenyl phosphate (DPHP). The detection frequencies of m-OPFRs ranged from 88.8 % to 95.4 %. BCEP had the highest median concentration (0.93 μg/L), followed by BCIPP (0.32 μg/L), DPHP (0.27 μg/L) and DBP (0.20 μg/L). Significant correlations were found between all pairs of urinary m-OPFRs with correlation coefficients ranging from 0.22 to 0.71 (p< 0.05). Logistic regression models showed that urinary concentrations of BDCIPP (adjusted odds ratio [OR]: 1.25, 95 % confidential interval [CI]: 1.04–1.50) and DBP (adjusted OR: 1.10, 95 % CI: 1.01–1.20) were positively associated with lower cognitive functions. Furthermore, a nonlinear dose-response relationship was found between urinary BDCIPP concentration and cognitive decline. To our knowledge, this is the first report on OPFR exposure and cognitive impairment among elderly population. Further toxicological tests of BDCIPP and DBP are needed to illustrate these results.

Exploring the Role of Organic Functional Groups in the Ionothermal Synthesis of Uranyl Phosphate Materials

AbstractFour new hybrid organic‐inorganic uranyl phosphate compounds were structurally characterized after single crystals were grown via ionothermal synthesis using the ionic liquids 1‐ethyl‐3‐methylimidazolium dimethyl phosphate and 1‐ethyl‐3‐methylimidazolium dibutyl phosphate. Three of the new crystal structures presented here incorporate dimethyl or monomethyl phosphate ligands into the structural unit to form one chain‐based compound and two sheet‐based compounds. One of the structures utilizes dibutyl phosphate to form a previously reported uranyl compound, a structural polymorph that crystallized in space groupP21/cin contrast to the previously reportedP‐1 structure. The structural and topological relationships are compared to those of uranyl phosphate minerals as well as previously reported organophosphate compounds. The roles of the organics on the phosphate anions in impacting uranyl coordination and stabilizing the crystal structures are discussed.

Associations between organophosphate esters metabolites and sleep disorder and trouble sleeping in adults: a machine-learning approach.

Organophosphate esters (OPEs) are used widely as flame retardants and plasticizers. However, the associations between OPEs metabolites and sleep outcomes (sleep disorder and trouble sleeping) remain unknown. Data utilized in this cross-sectional study was from the National Health and Nutrition Examination Survey 2013-2014, including 1393 adults aged ≥ 20years. We conducted weighted logistic regression and Bayesian kernel machine regression (BKMR) models to analyze the associations between OPEs metabolites and sleep outcomes. We included data from 2011 to 2012 cycle in our sensitivity analysis to explore the association further. Logistic regression model presented a significant positive association between diphenyl phosphate (DPHP) and sleep disorder in all participants (odds ratio (95% confidence interval) for the second quartile was 2.46 (1.85, 3.28)). We observed positive associations between OPEs metabolites and sleep outcomes in males. Among females, no significant association was observed in the logistic model. BKMR presented that dibutyl phosphate (DBUP) was the relatively important exposure. There was a positive association between OPEs metabolites mixture and trouble sleeping. Univariable exposure-response functions demonstrated U-shaped associations between DBUP and sleep outcomes, while bis(2-chloroethyl) phosphate (BCEP) was associated with sleep disorder negatively in females. No substantial changes appeared in the results after including the data from 2011 to 2012 cycle. This current study indicated that OPEs metabolites might be associated with sleep disorder and trouble sleeping, and the associations seemed to be sex-dependent.

The effect of radiolysis and thermally stimulated acid hydrolysis on tributyl phosphate and its solutions in ISOPAR-M

The radiolytic and post-radiation thermochemical (at 90–170 °C) transformations of tri-n-butyl phosphate (TBP) and its 30% solution into Isopar-M during pre-radiation and post-radiation acidification with nitric acid have been investigated. The assortment of nitrogen-containing products of TBP oxidation during gamma radiolysis, electron beam radiolysis, and thermally stimulated acid hydrolysis is similar. Specific products of radiolysis are TBP dimer and alkyl adducts of dibutyl phosphate, and specific products of thermolysis are ethylbenzene and xylenes. It was shown that, in contrast to 100% TBP, where radiolysis and hydrolysis have approximately the same additive effect on the degradation of TBP, hydrolysis in a 30% solution leads to the degradation of nitrogen-containing radiolysis products and additional formation of dibutyl phosphate and monobutyl phosphate. Temperatures above 110 °C during post-radiation thermolysis intensify the formation of highly volatile compounds from radiolysis products (up to 17 wt% at 170 °C), which increases the fire and explosion hazard of using extraction mixtures.

Association of urinary organophosphate esters level with sex steroid hormones levels in adult males: A nationwide study, NHANES 2013-2014.

Exposure to environmental pollution via different mechanisms is associated with multiple endocrine dysfunctions. Organophosphate esters (OPEs) are endocrine-disrupting chemicals that affect sex steroid hormones. We aimed to study the effect of OPEs and their metabolites, such as diphenyl phosphate (DPHP), bis(1,3-dichloro-2-propyl) phosphate (BDCPP), bis(2-chloroethyl) phosphate (BCEP), and dibutyl phosphate (DBUP), on sex steroid hormones in males. This cross-sectional analytical study analyzed data from the 2013-2014 National Health and Nutrition Examination Survey among 763 male participants aged ≥20 years. The relationships between the metabolites of OPEs and total testosterone, estradiol, sex hormone-binding globulin, and the ratio of total testosterone to estradiol (a parameter derived from total testosterone and estradiol) were evaluated using multivariate linear regression models that were adjusted for potential confounders. A total of 763 participants, with a mean age of 44.59 (±15.59) years, were enrolled. Of these, 65.7% participants had non-Hispanic white ancestry, 9.83% had non-Hispanic black ancestry, and 15.97% had Hispanic ancestry. Participants with higher urinary level of DPHP had a lower level of total testosterone and estradiol. Moreover, higher urinary levels of BDCPP were associated with higher estradiol. According to our study, which is based on a representative population of US adults, exposure to OPEs was significantly associated with altered sex hormone levels (total testosterone and estradiol). Further studies focused on the underlying mechanisms regarding the association between each metabolite and sex steroid hormones are required.

Hydrolysis Kinetics of Dibutyl Phosphate in 2.0 mol/L HNO3 Medium

Hydrolysis Kinetics of Dibutyl Phosphate in 2.0 mol/L HNO3 Medium

Structure and dynamics of dibutylphosphate/n-propylamine ionic liquid: A multi-scale theoretical study

Owing to the amphiphilic nature of their constituent molecules, binary mixtures of pure liquid surfactants are usually characterized by enhanced nano-segregation and thus can exhibit interesting transport properties and complex macroscopic behavior. In this ambit it was recently shown by Turco Liveri et al. (2018) that mixtures of short aliphatic chains compounds at room temperature, such as dibutyl phosphate (DBP) and n-propylamine (PA) liquids, display ionic liquid–like behavior ascribed to phosphate-to-amine proton transfer. To gain a detailed molecular picture of the system structure and dynamics and to understand the molecular mechanisms at the basis of the observed behavior, in the present study a combination of ab initio Density Functional Theory (DFT) calculation and ab initio Molecular Dynamics (AIMD) simulation has been carried out on DBP + PA clusters. It was found that in these systems the proton transfer is a cooperative process boosted by the concerted interactions of more than one DBP-PA pair. Moreover, classical molecular dynamics (MD) simulations of large DBP + PA systems showed that, triggered by steric effects due to the alkyl chains of both components, these interactions are able to build an extended network of polar domains embedded in an apolar environment of alkyl chains.

Pollution profiles and human health risk assessment of atmospheric organophosphorus esters in an e-waste dismantling park and its surrounding area

Recycling e-waste has been recognized as an important emission source of organophosphate triesters (tri-OPEs) and organophosphate diesters (di-OPEs), but the presence of di-OPEs in atmosphere has not been studied. Herein, tri-OPEs and di-OPEs in atmosphere of an e-waste dismantling park and surrounding area in South China were monitored for three consecutive years. Thirteen tri-OPEs and seven di-OPEs were identified. In 2017, 2018, and 2019, tri-OPE concentrations in e-waste dismantling park were 1.30 × 108, 4.60 × 106, and 4.01 × 107 pg/m3, while di-OPE concentrations were 1.14 × 103, 1.10 × 103, and 0.35 × 103 pg/m3, respectively, which were much higher than the surrounding area. Tri-OPEs and di-OPEs generated during e-waste dismantling affected surrounding area through diffusion. Triphenyl phosphate (TPhP) and diphenyl phosphate (DPhP) were the predominant congeners of tri-OPEs and di-OPEs, respectively. Additionally, TPhP concentration was extremely higher than other tri-OPEs, so TPhP could be used as an indicator of e-waste dismantling. Spearman correlation analysis showed significant correlations between DPhP and TPhP (R2 = 0.53, p < 0.01), bis-(1-chloro-2-propyl) phosphate (BCIPP) and tris(2-chloropropyl) phosphate (TCIPP) (R2 = 0.49, p < 0.01), as well as dibutyl phosphate (DBP) and tributyl phosphate (TBP) (R2 = 0.53, p < 0.01), indicating that they had the same source. Further, non-carcinogenic risk of them to people via inhalation was acceptable and non-carcinogenic risk of tri-OPEs decreased year by year in surrounding area.

New cerium-loaded phosphine oxide-functionalized polyurethane foam materials – Synthesis, stability, comparison of coordination behavior and catalytic applications

Phosphine oxides (R3P=O) are very well-known as reagents, ligands as well as catalysts in various chemical transformations. Among them, numerous molecules and polymers possessing phosphine oxide moieties have been employed as ligands in the chemistry of f-metals. In this regard, the present work describes the synthesis and characterization of three different new PO-functionalized polyurethane foams (PUFs) and their corresponding Ce-loaded PUFs (Ce-PUFs). The coordination behavior of these PUFs is evaluated with cerium salts and is compared with selected phosphine oxide molecules such as triphenylphosphine oxide (TPPO), trioctylphosphine oxide (TOPO), dibutyl phosphate (DBP), and bisphosphoramide (BAmPO). The single-crystal X-ray analysis describes that one of the Ce(III) complexes of bisphosphoramide appears as an infinite coordination polymer by intermolecularly bridged-phosphine oxide ligands. As a measure of coordination strength, the ligand-exchange reactions follow the trend as PUF > TOPO > BAmPO > TPPO > DBP and indicating the strong metal-binding capacity of PUFs more than the monomeric and dimeric phosphine oxides. According to the thermogravimetric analysis, the thermal stability of the metal complexes is observed as Ce(IV)-PUFs > [Ce(NO3)4(TOPO)4] > [Ce(NO3)4(BAmPO)2] > [Ce(NO3)4(TPPO)4] > [Ce(NO3)2(DBP)2]. Among all, the Ce-loaded foam materials displayed the highest stability and exchange the other ligands instantaneously. Further, the Ce(IV)-PUFs are found to be stable, non-leachable, and re-usable (more than 10 cycles) catalysts in high yield synthesis of biscoumarin derivatives.

The associations between organophosphate esters and urinary incontinence in the general US population

Organophosphate esters (OPEs) impact health in many ways. Since its relationship with urinary incontinence remains unknown, we aimed to explore their associations in the US general population. We combined the results of urine specimens test and self-reported urinary incontinence conditions from the National Health and Nutrition Examination Survey (NHANES) 2013–2014 among 2666 participants and then conducted linear regression and logistic regression to analyse associations between log2-transformed OPE concentrations and urinary incontinence. We found that 0.92% of men and 15.74% of women complained of mixed urinary incontinence (MUI). The concentrations of diphenyl phosphate (DPHP) were significantly correlated to MUI among women when treated as a continuous variable (adjusted odds ratio (OR) = 1.15; 95% confidence interval (CI), 1.01–1.31; p = 0.0369) and as a categorical variable (adjusted OR = 1.24; 95% CI, 1.03–1.49; p for trend = 0.0245), whereas no positive correlation was found in males. There were no significant associations between the other three OPEs: bis(2-chloroethyl) phosphate (BCEP), bis(1,3-dichloro-2-propyl) phosphate (BDCPP) and dibutyl phosphate (DBUP). The association of DPHP with an increased prevalence OR of MUI in women is a public health concern; future prospective studies are needed to explore its potential mechanism.

Functionalized phosphate ionic liquids as additives in PEG with excellent tribological properties for boundary/mixed/elastohydrodynamic lubrication

The 2,4,6-triamino-1,3,5-triazin-1-ium dibutyl phosphate (NP44) and 2,4,6-triamino-1,3,5-triazin-1-ium diisopentyl phosphate (NP88) were prepared as additives of PEG. In terms of temperature, slip-to-roll ratio and concentration, the effect of additives on tribological performance was explored. Excitingly, PEG with NP44 and NP88 presents outstanding lubricating property because of stable protective films formed in boundary/mixed lubrication. Furthermore, it was found that NP44 and NP88 can enhance film thickness in elastohydrodynamic lubrication when PEG was supplied with a limited quantity. It is attributed to the fact that adsorption of additives can reduce the surface energy to delay the oil depletion on the lubrication track.

Organophosphate and organohalogen flame retardant exposure and thyroid hormone disruption in women firefighters and office workers from San Francisco

BACKGROUND AND AIM: Organophosphate flame retardants (OPFR) are suspected endocrine disrupting compounds and have been detected in fire station dust and firefighter gear. Studies have reported that exposure to FRs can disrupt thyroid hormone (TH) function; however, this relationship is not well characterized, especially for halogenated OPFRs. TH is important for thyroid mediated gene expression and may be relevant to adverse health effects such as cardiovascular disease and cancer. We describe OPFR exposure and its association with TH levels in a cohort of women firefighters and office workers from San Francisco. METHODS: Using liquid chromatography-tandem mass spectrometry (LC MS/MS), we measured 8 urinary FR metabolites in female firefighters (N=86) and office workers (N=84) from San Francisco: bis(1,3-dichloro-2-propyl) phosphate (BDCPP), bis(2-chloroethyl) phosphate (BCEP), dibutyl phosphate (DBuP), dibenzyl phosphate (DBzP), di-p-cresyl phosphate (DpCP), di-o-cresyl phosphate (DoCP), 2,3,4,5-tetrabromobenzoic acid (TBBA), tetrabromobisphenol-A (TBBPA). We assessed potential predictors of exposure levels and the association between FR exposures and thyroxine (T4) and thyroid stimulating hormone (TSH) for 84 Firefighters and 81 office workers. RESULTS:BDCPP, BCEP and DBuP had the highest concentrations among all study participants. However, firefighters had higher median exposure levels of BDCPP, BCEP and DBuP compared to office workers. When we assessed the association of each FR with TH we found that a doubling of BDCPP was associated with a 2.88% decrease (95%CI -5.28,-0.42) in T4 among firefighters. We did not observe significant associations between FR and T4 among office workers nor between FR and TSH in either firefighters or office workers. CONCLUSIONS:Firefighters had significantly higher exposures to FR compared to office workers and their exposure to BDCPP was associated with TH disruption. Characterizing exposure to endocrine disrupting chemicals and assessing the association with biomarkers of early effect such as TH can inform prevention efforts without having to wait for adverse health outcomes to occur. KEYWORDS: occupational exposures, women firefighters, endocrine disruption

High performance task-specific ionic liquid in uranium extraction endowed with negatively charged effect

Designing functionalized task-specific ionic liquid is a promising way to alleviate the potential second pollution caused by the usage of tributyl phosphate in PUREX process. In this work, a new anion-functionalized ionic liquid, N,N,N-trimethyltetradecan-1-aminium dibutyl phosphate ([N14111][DBP]), was synthesized and applied in uranium extraction. Thanks to the negatively charged effect, [N14111][DBP] exhibits high efficiency in uranium separation, at optimized condition, the maximum of distribution ratio (concentration of ions in extractant to concentration of ions in aqueous solution) for UO22+ could reach 343.5. What’s more, the selectivity of [N14111][DBP] for UO22+ from transition metal ions was also examined in simulated nuclear industry effluent containing and UO22+ ions were separated and extracted efficiently. The advantage of extraction efficiency and selectivity of [N14111][DBP] compared with DBP highlight the superiority of anion-functionalized extractant.

Mechanism analysis of extractive distillation for separation of acetic acid and water based on quantum chemical calculation and molecular dynamics simulation

The selection of high efficiency and environmental protection entrainer is the inevitable requirement of extractive distillation sustainable development. According to the extraction mechanism, the σ-profile was drawn by COSMO-SAC model. Based on the quantum chemistry method, the interaction energy, deformation charge density and total charge density of different organic solvent, ionic liquids and acetic acid-water system were calculated. The binding energy between organic solvents, ionic liquids and acetic acid-water system was further analyzed by Gaussian software. The binding energies of organic solvent tetramethylene sulfone and 1-butyl-3-methylimidazolium dibutyl phosphate ([BMIM][BDP]) ionic liquid with acetic acid were - 934.9622 a.u., − 1610.6557 a.u., respectively. Through molecular dynamics simulation, the radial distribution functions of organic solvents and ionic liquids were calculated and compared at the molecular level, and the interaction between different molecules was analyzed. The cation plays a leading role. When Å = 4.5, ionic liquid and solvent interact strongly with acetic acid, respectively. The comprehensive results showed that tetramethylene sulfone and [BMIM][BDP] had better extraction effect. Finally, the self-diffusion coefficient of [BMIM][BDP] and HAc is 0.0105 cm2 / s. The combination of quantum chemical calculation and molecular dynamics simulation provides theoretical guidance for the effective separation of acetic acid-water system, which provides a certain reference for the selection of the best entrainer.

Organophosphate Diesters in Urban River Sediment from South China: Call for More Research on Their Occurrence and Fate in Field Environment

Despite numerous studies on the distributions of organophosphate triesters (tri-OPEs) in various environmental compartments, few have investigated organophosphate diesters (di-OPEs) in natural environments. This study was conducted to examine the co-occurrence of tri- and di-OPEs in urban river sediment. The concentrations (range (median); dry weight) of ∑tri-OPE and ∑di-OPE were 17–4400 (330) and 9.0–1200 (130) ng g–1, respectively. The concentrations of diphenyl phosphate (DPHP), bis-(1-chloro-2-propyl) phosphate (BCIPP), bis(2-ethylhexyl) phosphate (BEHP), dibutyl phosphate (DBP), and bis-(butoxyethyl) phosphate (BBOEP) were 1.7–520 (45), 3.2–590 (51), 1.7–100 (22), 0.43–9.6 (1.2), and 0.41–4.4 (0.74) ng g–1, respectively. Positive correlations between the levels of di-OPE and tri-OPE compounds (p < 0.05) together with high concentration ratios of DPHP to TPHP (2.0–96; median 17) and BCIPP to TCIPP (1.6–160; median 5.7) suggested that DPHP and BCIPP were mainly from degradation of TPHP and TCIPP. More studies are needed to illustrate the environmental occurrence, behavior, fate, and ecological risk of di-OPEs.

Non-ideal mixing behavior in dibutyl phosphate-propylamine binary liquids: Dielectric and nuclear magnetic resonance investigations

Owing to the amphiphilic nature of their constituent molecules, binary mixtures of pure liquid surfactants are usually characterized by enhanced nano-segregation and thus can exhibit interesting transport properties and complex macroscopic behavior. In this ambit it was recently shown by Turco Liveri et al. (J. Mol. Liq. 263 (2018) 274–281) at room temperature that mixtures of short aliphatic chains compounds, such as dibutyl phosphate (DBP) and n-propylamine (PA) liquids, due to their ability to allow for phosphate-to-amine proton transfer, display ionic liquid–like behavior with composition-dependent enhanced conductivity, viscosity, and magnetically-induced birefringence. To understand the molecular mechanisms at the basis of this behavior, in the present study a combination of nuclear magnetic resonance (NMR) and dielectric spectroscopy investigations has been carried out for the same materials for different amine molar ratios. It was found that at certain compositions all studied dynamical processes (conformational changes, local hopping of “free” protons among neighboring polar headgroups, long-range charge migration) exhibit significant deviations from ideal mixing behavior. The microscopic origin of these deviations is discussed.

Gestational exposure to organophosphate esters (OPEs) and maternal blood pressure during pregnancy: The HOME Study

Background: After the phase-out of polybrominated diphenyl ethers, exposure to organophosphate esters (OPEs), which are potential endocrine disruptors, is ubiquitous. No study has examined the associations between gestational exposure to OPEs and blood pressure and the risk of pregnancy-induced hypertensive diseases.Methods: We used data from 333 women who had liveborn singletons without congenital abnormalities in the Health Outcomes and Measures of the Environment (HOME) Study, a prospective birth cohort. We quantified maternal urinary OPE metabolites at 16 weeks of gestation. Outcomes included the highest maternal blood pressure measurement at ≥20 weeks of gestation and pregnancy-induced hypertensive diseases (gestational hypertension, preeclampsia, and eclampsia) from medical chart review. We used linear regression and modified Poisson regression with covariate adjustment to estimate the associations of exposure with blood pressure and the risk of pregnancy-induced hypertensive diseases, respectively.Results: Diphenyl phosphate (DPHP) had the highest geometric mean urinary concentrations (1.65 µg/g creatinine), followed by bis(1,3-dichloro-2-propyl) phosphate (BDCIPP; 0.76 µg/g creatinine), bis(2-chloroethyl) phosphate (BCEP; 0.70 µg/g creatinine), and dibutyl phosphate (DBUP; 0.25 µg/g creatinine). There were 29 (8.7%) women diagnosed with pregnancy-induced hypertensive diseases. Average systolic and diastolic blood pressure, measured at an average of 31 weeks gestation (range: 20-41), were 117±13 and 72±9 mmHg, respectively. None of the urinary OPE metabolites were significantly associated with the highest maternal blood pressure at ≥20 weeks of gestation, nor were they strongly associated with an increased risk of pregnancy-induced hypertensive diseases. The relative risk (RR; 95% confidence interval) of pregnancy-induced hypertensive diseases by a 10-fold increase in exposure was 1.31 (0.66, 2.59) for DPHP, 1.36 (0.51, 3.67) for BDCIPP, 0.63 (0.16, 2.39) for BCEP and 2.13 (0.78, 5.77) for DBUP.Conclusion: This study suggests no associations between maternal urinary OPE metabolite concentrations and blood pressure or an increased risk of pregnancy-induced hypertensive diseases during pregnancy.

Vitamin status on the association between organophosphate esters (OPEs) exposure and chronic kidney disease

Background/Aim: Organophosphate esters (OPEs) are used in various materials and consumer products as flame retardants and plasticizers. Both experimental and epidemiological studies have suggested adverse effects of OPEs on the kidney function. However, it is unknown whether vitamin plays protective role on the OPE-associated chronic kidney disease. In this study, effect modification of vitamin status on the association between OPE exposure and chronic kidney disease was hypothesized. Data from the US National Health and Nutrition Examination Survey (NHANES) 2013-2014 were employed. Methods: A total of 1515 adults were identified in the US NHANES 2013-2014 without kidney failure and current pregnancy and with relevant measurements, e.g., vitamin status (RBC folate, serum vitamin B12, and vitamin D), estimated glomerular filtration rate (eGFR), albumin-to-creatinine ratio (ACR), and urinary metabolites of OPEs. Linear regression models were constructed to evaluate effect modification of vitamin concentrations in the association of urinary metabolites of OPEs, i.e., bis(1,3-dichloro-2-propyl) phosphate (BDCIPP), bis(2-chloroethyl) phosphate (BCEP), and dibutyl phosphate (DNBP), with eGFR or ACR. Moreover, the association was evaluated following stratification by vitamin status (low-level: &lt;30th percentile; mid-level: ≥30th and &lt;70th percentile; high-level: ≥ 70th percentile). Results: Significant effect modification of vitamin D was observed. Increase of vitamin D was associated with decreased effect sizes of OPEs exposure on the association with eGFR. Following stratification, associations of OPEs exposure with eGFR were significant only in the low-level vitamin D group while the associations were insignificant, and the effect sizes were decreased in the mid- and high-level groups. However, vitamin D did not show any effect modification on ACR. For folate and vitamin B12, no effect modification was observed. Conclusions: Vitamin D status appears to modify the effects of OPEs exposure on chronic kidney disease in general population. Confirmations in other populations are warranted.