Dimethyl Phosphate Research Articles

The Association Between Urinary Concentrations of Organophosphate Metabolites and Asthma-Related Outcomes Among Schoolchildren From Informal Settlements.

Objectives: There is inconsistent evidence on the relationship between pesticide exposure and childhood respiratory outcomes in non-agricultural settings. This study investigated the association between organophosphate (OP) pesticide exposure and asthma-related outcomes in children residing in four informal settlements. Methods: The study was a longitudinal study of 590 schoolchildren, with a 12months follow-up period. A standardised questionnaire adopted from the International Study of Asthma and Allergies in Childhood was administered to caregivers for child's respiratory symptoms and household characteristics. Spirometry and fractional-exhaled nitric oxide, including a phadiatop test (atopy status) and urinary dialkyl phosphate (DAP) metabolites were measured at baseline and follow-up. DAP metabolites included diethylphosphate (DEP) and dimethyl phosphate (DMP) measured at baseline and follow-up and dimethylthiophosphate (DMTP) measured only at baseline. Results: The mean ages of schoolchildren were 9.9 ± 0.91years and the overal incidence proportions of new doctor diagnosed asthma was 2.2%. No consistent patterns of increased risk of asthma outcomes with increasing DAP concentrations was found in multivariate analysis. Conclusion: Future studies with longer follow-up periods and repeated OP biomonitoring are recommended.

The study of excess enthalpy for {ionic liquid + ethanol} binary systems as new working fluids in absorption refrigeration technology

Binary systems composed of phosphonium – based ionic liquid and water, or short-chain alcohols exhibit properties which render them suitable as candidates for working fluids in absorption refrigeration technology. This work presents the study of the excess enthalpy (HE) of mixing in ethanolic solutions of the following ionic liquids: 1-ethyl-1-methylpiperidinium dimethyl phosphate, [C1C2PIP][DMP], 1-ethyl-1-methyl-pyrrolidinium dimethyl phosphate, [C1C2PYR][DMP], N,N,N-triethyl-N-methylammonium dimethyl phosphate, [N1,2,2,2][DMP],1-hydroxyethyl-1-methylpyrrolidinium dimethyl phosphate, [C1C2OHPYR][DMP], 1-ehtyl-1-methylmorpholinium diethyl phosphate, [C1C2MOR][DEP], 1-ethyl-1-methylpyrrolidinium diethyl phosphate, [C1C2PYR][DEP], and 1-ethyl-3-methylimidazolium diethyl phosphate, [C1C2IM][DEP] is presented. The experiment was performed at temperature T = 298.15 K and under ambient pressure using isothermal titration calorimetry technique. This work presents the effect of the core structure of the cation and the effect of the carbon chain length in the anion of the ionic liquid on the HE value of the systems studied. Experimental HE values were correlated using Redlich – Kister type equation. The standard deviations for the correlation vary from σ = 9 J∙mol−1 for {[C1C2OHPYR][DMP] + ethanol} to 28 J∙mol−1 for {[C1C2IM][DMP] + ethanol} showing significant agreement between experimental and calculated values. The negative excess enthalpy of mixing over the entire composition range was found in each system which indicate stronger (IL - ethanol) interactions associated with hydrogen bond formation in this system, compared to (IL - IL) and (ethanol - ethanol) interactions. For each system, the minimum of the excess enthalpy of mixing was determined, which increases in the following series: [N1,2,2,2][DMP] (HE = −2645.9 J·mol−1) < [C1C2PYR] [DMP] < [C1C2IM][DEP] < [C1C2PYR][DEP] < [C1C2PIP][DMP] < [C1C2MOR][DMP] < [C1C2OHPYR][DMP] (HE = −881.5 J·mol−1). This characteristic is desirable from the point of view of the possibility of using these systems in absorption refrigeration technology.

Effects of an organic diet intervention on the levels of organophosphorus metabolites in an adult cohort

Pesticides are a group of organic compounds used to control weeds or insect infestations in agriculture. Diet is the major route of human exposure to these compounds, which can cause serious health problems, even when the intake occurs at low concentrations. Hence, the consumption of organic food is an appropriate strategy to minimize the exposure to pesticides. A prospective, randomized study was conducted to assess the impact of an organic dietary intervention on the levels of urinary dialkyl phosphates (DAP). A screening of 204 pesticides was also carried out in order to confirm the absence of these compounds in organic food. The analytical results showed that only 20 of the 204 pesticides (9.8 %) had concentrations above the limit of quantification in one or more samples of the organic food consumed by the participants. It is substantially lower than the levels of pesticides found in other studies analysing conventional food, confirming the diet as suitable for the organic dietary intervention. A general reduction of most DAP metabolites in urine was found, being significant (p < 0.05) the decrease of dimethyl phosphate (DMP) (0.49 µg/g creatinine in Day 1 vs. 0.062 µg/g creatinine in Day 6), dimethyl thiophosphate (DMTP) (0.49 µg/g creatinine in Day 1 vs. 0.093 µg/g creatinine in Day 6) and diethyl phosphate (DEP) (0.28 µg/g creatinine in Day 1 vs. 0.12 µg/g creatinine in Day 6). In addition, the molar score for the total dimethyl DAP (ΣMP) and total dialkyl phosphate (ΣDAP) also showed significant differences after changing a conventional diet by an organic diet, being reduced from 0.008 µmol/g to 0.002 µmol/g for ΣMP and from 0.012 µmol/g to 0.003 µmol/g for ΣDAP. To the best of our knowledge, this is the first study that evaluates both the impact of an organic diet in the exposure to DAP and the levels of 204 pesticides in the organic food provided to the participants. In summary, the consumption of organic products decreases the dietary intake of pesticides, thus reducing also the potential adverse effects on human health.

Fetal Organophosphate Pesticide Exposure and Child Adiposity Measures at 10 Years of Age in the General Dutch Population.

Fetal exposure to organophosphate (OP) pesticides might lead to fetal metabolic adaptations, predisposing individuals to adverse metabolic profiles in later life. We examined the association of maternal urinary OP pesticide metabolite concentrations in pregnancy with offspring body mass index (BMI) and fat measures at 10 years of age. Between 2002 and 2006, we included 642 mother-child pairs from the Generation R Study, a population-based prospective cohort study in Rotterdam, the Netherlands. We measured maternal urinary concentrations of OP pesticide metabolites, namely, dialkyl phosphates, including three dimethyl and three diethyl phosphates in early-, mid- and late-pregnancy. At 10 years of age, child total and regional body fat and lean mass were measured through dual energy X-ray absorptiometry, and abdominal and organ fat through magnetic resonance imaging. Higher maternal urinary pregnancy-average or trimester-specific dialkyl, dimethyl, or diethyl phosphate concentrations were not associated with childhood BMI and the risk of overweight. In addition, we did not observe any association of dialkyl, dimethyl, or diethyl phosphate concentrations with total and regional body fat, abdominal visceral fat, liver fat, or pericardial fat at child age of 10 y. We observed no associations of maternal urinary dialkyl concentrations during pregnancy with childhood adiposity measures at 10 years of age. Whether these associations develop at older ages should be further studied. https://doi.org/10.1289/EHP12267.

Development and Validation of a New UFLC-MS/MS Method for the Detection of Organophosphate Pesticide Metabolites in Urine.

To monitor human exposure to pesticides, experts commonly measure their metabolites in urine, particularly dialkyl phosphates (DAPs), which include diethyl phosphate (DEP), Diethyl thiophosphate (DETP), diethyl dithiophosphate (DEDTP), dimethyl phosphate (DMP), dimethyl thiophosphate (DMTP) and dimethyl dithiophosphate (DMDTP)to monitor the metabolites of organophosphates. These DAP metabolites are a urinary biomarker for assessing pesticide exposure and potential health risks. This study presented a new screening method combining ultrafast liquid chromatography with tandem mass spectrometry (UFLC-MS/MS) to detect six DAP metabolites in human urine. The study also compared standard sample extraction methods, namely, liquid-liquid extraction (LLE); quick, easy, cheap, effective, ruggedand safe (QuEChERS); and lyophilization. After a comprehensive analysis of the methods used to extract the analytes, including recovery rate, repeatability and reproducibility, the liquid-liquid extraction (LLE) method was found to be the best. It had a high recovery rate, was easy to handle, required less sample volume and had a short extraction time. Therefore, the LLE method was chosen for further analysis. The results showed excellent performance with high recoveries between 93% and 102%, precise repeatability (RSD) between 0.62% and 5.46% and acceptable reproducibility values (RSD) between 0.80% and 11.33%. The method also had limits of detection (LOD) ranging from 0.0201 ng/mL to 0.0697 ng/mL and limits of quantification (LOQ) ranging from 0.0609 ng/mL to 0.2112 ng/mL. Furthermore, the UFLC-MS/MS method was validated based on the SANTE guidance and successfully analyzed 150 urine samples from farmers and non-farmers. This validated method proved useful for biomonitoring studies focusing on OP pesticide exposure. It offers several advantages, such as a reduced need for samples, chemicals and materials, and a shorter analysis time. The method is sensitive and selective in detecting metabolites in human urine, making it a valuable approach for the practical and efficient assessment of pesticide exposure.

Effect of ionic liquid as corrosion inhibitor for 6061 aluminium alloy-(electrochemical and quantum chemical approaches)

ABSTRACT Ionic liquid 1,3-dimethylimidazolium dimethyl phosphate (DIDP) is used as a possible green inhibitor for the corrosion control of 6061 aluminium alloy in 0.25 mol/L HCl is described in the study. Study involved electrochemical methods carried out at various temperatures by changing the concentrations of DIDP. Kinetic and thermodynamic parameters were determined using the Arrhenius rate law and transition state equations, respectively. Physisorption of the inhibitor takes place and the adsorption follows Freundlich isotherm. Surface morphology was studied by scanning electron microscopy (SEM), atomic force microscopy (AFM), and energy-dispersive X-ray analysis (EDAX) techniques. Quantum chemical studies were done by the density functional theory (DFT). The maximum inhibition efficiency of DIDP on 6061 aluminium alloy was about 78% for the concentration of 1000 ppm at 303 K. The mechanistic aspects of DIDP adsorption onto the metal surface were supported by quantum chemical studies. HOMO and LUMO of the optimized structure and quantum chemical descriptors confirmed the adsorption of the inhibitor on the metal surface. Mulliken charge population was used to identify the DIDP molecule’s high electron density region, and Fukui indices confirmed the interaction between metal and inhibitor.

Biomarkers of organophosphate insecticides exposure and asthma in general US adults: findings from NHANES 1999-2018 data.

The limited evidence linking exposure to organophosphate insecticides (OPIs) and asthma in the general population prompted us to investigate this association. Our study focused on US adults and utilized representative samples from the National Health and Nutrition Examination Survey (NHANES). From the 7 NHANES waves (1999-2018), we detected OPIs exposure using the urinary concentrations of six metabolites of dialkyl phosphates (DAPs). To evaluate the relationship between these OPIs and asthma, we employed three statistical methods: survey-multivariable logistic regression (SMLR), generalized weighted quantile sum (WQS) regression, and Bayesian kernel machine regression (BKMR). Stratified analyses were done based on the relevant variable subgroups, and sensitivity analyses were carried out to evaluate the robustness of findings. A total of 6009 adults aged from 20 to 85 years old, representing the 313.5 million adults in the non-institutionalized US population, were included in our analyses. Among them, 842 participants were determined as asthma patients with an age-adjusted prevalence of 14.2%. Our results showed that dimethyl phosphate (DMP) (adjusted odd ratio (AOR) = 1.471, 95% CI: 1.086, 1.993), diethyl phosphate (DEP) (AOR = 1.453, 95% CI: 1.118, 1.888), dimethyl thiophosphate (DMTP) (AOR = 1.454, 95% CI: 1.071, 1.973), and dimethyl dithiophosphate (DMDTP) (AOR = 1.478, 95% CI: 1.119, 1.953) had a positive correlation with asthma in adults. This association was stronger in females, non-Hispanic White populations and those with a small amount of physical activity. Our study findings indicated that exposure to OPIs may elevate the risk of asthma in US general adults. Specifically, females, individuals from non-Hispanic White backgrounds, and those with lower levels of physical activity are more susceptible to developing asthma when exposed to OPIs.

Methylated and ethylated dialkylphosphate metabolites of organophosphate pesticides: DNA damage in bone marrow cells of Balb/c mice.

Dialkylphosphates (DAPs), metabolites of organophosphate (OP) pesticides, are widely distributed in the environment and are often used as biomarkers of OP exposure. Recent reports indicate that DAPs may be genotoxic, both in vitro and in vivo. We have examined the genotoxicity of the methylated DAPs dimethyldithiophosphate (DMDTP) and dimethylphosphate (DMTP) and the ethylated DAPs diethyldithiophosphate (DEDTP) and diethylphosphate (DETP), in comparison with their parental compounds, malathion and terbufos, respectively, in bone marrow polychromatic erythrocytes (PCE) of male and female Balb/c mice. We also compared DNA damage (comet assay) induced by DMDTP and dimethyl phosphate (DMP) in human cell lines. Both DMDTP and DMP caused DNA damage in peripheral blood mononuclear cells, HeLa cells, and the hepatic cell lines HepG2 and WRL-68. In the in vivo micronucleus assay, methylated and ethylated DAPs increased micronucleated PCE cells in both male and female mice. Female mice were more susceptible to DNA damage. In comparison to their parental compounds, methylated DAPs, particularly DMTP, were more genotoxic than malathion; DEDTP, DETP, and terbufos were similar in potency. These results suggest that DAPs may contribute to DNA damage associated with OP pesticide exposure.

Ameliorative Effects of Vitamins C and E on Haematotoxicity and Spleen Histopathology Induced by Dichlorvos Insecticide in Female Wistar Rats

This research aimed to assess the toxicological effects of dichlorvos insecticide (2,2-dichlorovinyl dimethyl phosphate or DDVP) on haematological indices of female Wistar rats and to investigate the antioxidant properties of vitamins C and E in ameliorating haematotoxicity. The rats were divided into 6 groups; control-water, control-oil, dichlorvos group, dichlorvos + vitamin C group, dichlorvos + vitamin E group and dichlorvos + vitamin C + E group. Dichlorvos and vitamins were orally administered to rats with an interval of half an hour between treatments. The control-oil group was given 2 ml corn oil and the control-water group was given water adlib. The treatments were done for 28 consecutive days and blood samples were taken by cardiac puncture. The following haematological parameters were analysed: RBC, WBC, Hb, PCV, MCV, MCH, MCHC and THR. Bone marrow smears were prepared on 14th and 28th days for various blood stem cells evaluation and spleen tissues for histopathology. There was a significant decrease (p ˂ 0.01) in RBC counts, PCV, MCV and MCH values, whereas the WBC, THR counts and MCHC values increased significantly (p ˂ 0.01) in dichlorvos treated rats as compared to the controls and dichlorvos + vitamins co-treated groups. There were no significant differences in blood parameter counts between controls and dichlorvos + vitamins co-treated groups. In the bone marrow smear of the dichlorvos treated group, there was increased number of megakaryocytes and mature neutrophils. In conclusion, findings from the current study revealed that, vitamins C and E supplements were capable of mitigating the haematotoxic effects induced by dichlorvos insecticide in Wistar rats.

Combining Tailored Ionic Liquids with Ti3C2Tx MXenes for an Enhanced Load‐Carrying Capacity Under Boundary Lubrication

To improve the efficiency and lifetime of mechanical components, new lubrication systems are needed. Two complementary material classes, which have demonstrated a promising tribological performance, are ionic liquids and MXenes (2D transition metal carbides and nitrides). Herein, Ti3C2Tx MXenes are used as additives in ionic liquids (ILs) to improve their load‐carrying capacity under boundary lubrication. The specifically synthesized ILs share the same cation (trioctyl(methyl)phosphonium) but different anions (dimethyl phosphate and dibutyl phosphate for IL1 and IL2, respectively) to assess the effect of the anion's alkyl chain length. The wear reduction performance is tested with a cylinder‐on‐ring contact in a standardized Brugger tester, which is suitable to study boundary lubrication and to assess the antiwear ability of the IL/MXene lubricant blends. MXenes indicate an excellent dispersibility in both ILs over 24 h. It is found that, irrespective of the used IL, the addition of MXenes always increases the load‐carrying capacity. Particularly, significantly reduced wear and thus a high load‐carrying capacity are observed for the combination IL2/MXenes, which also outperform fully formulated commercially available lubricants such as turbine oils.

Dilute-and-shoot coupled to mixed mode liquid chromatography-tandem mass spectrometry for the analysis of persistent and mobile organic compounds in human urine

In this work, a comprehensive method for the simultaneous determination of 33 diverse persistent and mobile organic compounds (PMOCs) in human urine was developed by dilute-and-shoot (DS) followed by mixed-mode liquid chromatography coupled with tandem mass spectrometry (MMLC-MS/MS). In the sample preparation step, DS was chosen since it allowed the quantification of all targets in comparison to lyophilization. For the chromatographic separation, Acclaim Trinity P1 and P2 trimodal columns provided greater capacity for retaining PMOCs than reverse phase and hydrophilic interaction liquid chromatography. Therefore, DS was validated at 5 and 50 ng/mL in urine with both mixed mode columns at pH = 3 and 7. Regarding figures of merit, linear calibration curves (r2 > 0.999) built between instrumental quantification limits (mostly below 5 ng/mL) and 500 ng/mL were achieved. Despite only 60% of the targets were recovered at 5 ng/mL because of the dilution, all PMOCs were quantified at 50 ng/mL. Using surrogate correction, apparent recoveries in the 70–130% range were obtained for 91% of the targets. To analyse human urine samples, the Acclaim Trinity P1 column at pH = 3 and 7 was selected as a consensus between analytical coverage (i.e. 94% of the targets) and chromatographic runs. In a pooled urine sample, industrial chemicals (acrylamide and bisphenol S), biocides and their metabolites (2-methyl-4-isothiazolin-3-one, dimethyl phosphate, 6-chloropyridine-3-carboxylic acid, and ammonium glufosinate) and an artificial sweetener (aspartame) were determined at ng/mL levels. The outcomes of this work showed that humans are also exposed to PMOCs due to their persistence and mobility, and therefore, further human risk assessment is needed.

Effect of prenatal exposure to organophosphates and pyrethroid pesticides on neonatal anthropometric measures and gestational age

Several studies have examined the association between prenatal exposure to organophosphate and pyrethroid pesticides and their impact on foetal growth and newborn anthropometry; however, the available evidence is limited and inconclusive. This study examined whether prenatal organophosphate and pyrethroid pesticide exposure was associated with anthropometric measures at birth (weight, length, head circumference), ponderal index, gestational age, and prematurity in 537 mother-child pairs. These were randomly selected from the 800 pairs participating in the prospective birth cohort GENEIDA (Genetics, early life environmental exposures and infant development in Andalusia). Six non-specific organophosphate metabolites (dialkylphosphates, DAPs), one metabolite relatively specific to chlorpyrifos (3,5,6-trichloro-2-pyridinol, TCPy) and a common metabolite to several pyrethroids (3-phenoxybenzoic acid, 3-PBA) were measured in maternal urine from the 1st and 3rd pregnancy trimesters. Information on anthropometric measures at birth, gestational age and prematurity was retrieved from medical records. The sum on a molar basis of DAPs with methyl (ƩDMs) and ethyl (ƩDEs) moieties and the sum of the 6 DAPs metabolites (ƩDAPs) was calculated for both trimesters of pregnancy. High urinary levels of dimethyl phosphate (DMP) during the 3rd trimester were associated with a decrease in birth weight (β = −0.24; 95% CI: 0.41; −0.06) and birth length (β = −0.20; 95% CI: 0.41; 0.02). Likewise, ΣDMs during 3rd trimester were near-significantly associated with decreased birth weight (β = −0.18; 95% CI: 0.37; 0.01). In turn, increased urinary TCPy during 1st trimester was associated with a decreased head circumference (β = −0.31; 95% CI: 0.57; −0.06). Finally, an increase in 3-PBA in the 1st trimester was associated with a decreased gestational age (β = −0.36 95% CI: 0.65–0.08), whereas increased 3-PBA at 1st and 3rd trimester was associated with prematurity. These results indicate that prenatal exposure to organophosphate and pyrethroid insecticides could affect normal foetal growth, shorten gestational age and alter anthropometric measures at birth.

Methylated dialkylphosphate metabolites of the organophosphate pesticide malathion modify actin cytoskeleton arrangement and cell migration via activation of Rho GTPases Rac1 and Cdc42

The non-cholinergic molecular targets of organophosphate (OP) compounds have recently been investigated to explain their role in the generation of non-neurological diseases, such as immunotoxicity and cancer. Here, we evaluated the effects of malathion and its dialkylphosphate (DAP) metabolites on the cytoskeleton components and organization of RAW264.7 murine macrophages as non-cholinergic targets of OP and DAPs toxicity. All OP compounds affected actin and tubulin polymerization. Malathion, dimethyldithiophosphate (DMDTP) dimethylthiophosphate (DMTP), and dimethylphosphate (DMP) induced elongated morphologies and the formation of pseudopods rich in microtubule structures, and increased filopodia formation and general actin disorganization in RAW264.7 cells and slightly reduced stress fibers in the human fibroblasts GM03440, without significantly disrupting the tubulin or vimentin cytoskeleton. Exposure to DMTP and DMP increased cell migration in the wound healing assay but did not affect phagocytosis, indicating a very specific modification in the organization of the cytoskeleton. The induction of actin cytoskeleton rearrangement and cell migration suggested the activation of cytoskeletal regulators such as small GTPases. We found that DMP slightly reduced Ras homolog family member A activity but increased the activities of Ras-related C3 botulinum toxin substrate 1 (Rac1) and cell division control protein 42 (Cdc42) from 5 min to 2 h of exposure. Chemical inhibition of Rac1 with NSC23766 reduced cell polarization and treatment with DMP enhanced cell migration, but Cdc42 inhibition by ML-141 completely inhibited the effects of DMP. These results suggest that methylated OP compounds, especially DMP, can modify macrophage cytoskeleton function and configuration via activation of Cdc42, which may represent a potential non-cholinergic molecular target for OP compounds.

Genome-wide analysis of sex-specific differences in the mother–child PELAGIE cohort exposed to organophosphate metabolites

In recent decades, the detrimental effects of environmental contaminants on human health have become a serious public concern. Organophosphate (OP) pesticides are widely used in agriculture, and the negative impacts of OP and its metabolites on human health have been demonstrated. We hypothesized that exposure to OPs during pregnancy could impose damaging effects on the fetus by affecting various processes. We analyzed sex-specific epigenetic responses in the placenta samples obtained from the mother–child PELAGIE cohort. We assayed the telomere length and mitochondrial copy numbers using genomic DNA. We analyzed H3K4me3 by using chromatin immunoprecipitation followed by qPCR (ChIP‒qPCR) and high-throughput sequencing (ChIP-seq). The human study was confirmed with mouse placenta tissue analysis. Our study revealed a higher susceptibility of male placentas to OP exposure. Specifically, we observed telomere length shortening and an increase in γH2AX levels, a DNA damage marker. We detected lower histone H3K9me3 occupancy at telomeres in diethylphosphate (DE)-exposed male placentas than in nonexposed placentas. We found an increase in H3K4me3 occupancy at the promoters of thyroid hormone receptor alpha (THRA), 8-oxoguanine DNA glycosylase (OGG1) and insulin-like growth factor (IGF2) in DE-exposed female placentas. H3K4me3 occupancy at PPARG was increased in both male and female placentas exposed to dimethylphosphate (DM). The genome-wide sequencing of selected samples revealed sex-specific differences induced by DE exposure. Specifically, we found alterations in H3K4me3 in genes related to the immune system in female placenta samples. In DE-exposed male placentas, a decrease in H3K4me3 occupancy at development-related, collagen and angiogenesis-related genes was observed. Finally, we observed a high number of NANOG and PRDM6 binding sites in regions with altered histone occupancy, suggesting that the effects were possibly mediated via these factors. Our data suggest that in utero exposure to organophosphate metabolites affects normal placental development and could potentially impact late childhood.

Influence of exposure to pesticides on telomere length and pregnancy outcome: Diethylphosphates but not Dimethylphosphates are associated with accelerated telomere attrition in a Palestinian cohort

Exposure to environmental pesticides during pregnancy is associated with adverse health outcomes such as low birth weight and impaired neuro-development. In this study, we assessed maternal leukocyte telomere lengths (TL) in Palestinian pregnant women and compared the data with urinary organophosphate concentrations, demographic, lifestyle and dietary factors, birth weight, body length, gestational age, and head circumference. Women with high urine levels of creatinine adjusted diethylphosphate(DE)derived pesticide metabolites DEP, DETP or DEDTP had shorter telomeres (p = 0.05). Women living in proximity to agricultural fields had shorter telomeres compared to women not living in proximity to agricultural fields (p = 0.011). Regular consumption of organic food was associated with shorter telomeres (p = 0.01), whereas the consumption of other vegetables such as artichokes was rather associated with longer telomeres. By contrast, urine levels of dimethylphosphate(DM)-derived pesticide metabolites DMTP and DMDTP were associated with lower birth weight (p = 0.05) but not with shrter telomeres. In conclusion organophosphate pesticides and living in proximity to agriculture are associated with shorter TL, likely due to higher consumption of contaminated fruits and vegetables and/or the transport of pesticides to non-treatment sites. DE and DM substituted pesticides seem to have different effects on telomeres and development.

Isolated Cu-N5 sites engineered polypyrrole-reduced graphene oxide hybrids for enhancing room-temperature DMMP sensing

The hydrogen bonding interactions are potentially employed to fabricate high-performance room-temperature gas sensors for detection of organophosphorus. Nevertheless, the low response toward target gases of conventional sensing materials hinders their further applications. Herein, an isolated Cu-N5 sites engineering strategy is reported to improve sensing performances for polypyrrole-reduced graphene oxide hybrids (PPy-rGO)-based room-temperature dimethyl methyl phosphate (DMMP) sensors. The isolated Cu-N5 sites were simply constructed by adsorption of Cu2+ ions with PPy-rGO hybrids owing to strong metal-support interactions. X-ray absorption fine structure analysis indicates that Cux+ ions with mean chemical valence of + 1.07 nearly atomically distributed on support with coordination structure of Cu-N5. Benefiting from the structure regulation by Cux+ ions, as-constructed DMMP sensor demonstrated 4.5-fold improvement in response to 100 ppm DMMP and 2.5-fold improvement in limit of detection, compared to PPy-rGO hybrids. The density functional theory, spectroscopic characterizations and quartz crystal microbalance tests prove that the construction of Cu-N5 sites not only heightens hydrogen bonding interactions between NH bonds and DMMP molecules induced by newly formed coordination interactions between Cux+ ions and NH bonds, but also serves as new active sites for adsorption of DMMP molecules. This work offers a new avenue for developing high-performance room-temperature gas sensors by heightening hydrogen bonding interactions.

Spontaneously super-hygroscopic MOF-gel microreactors for efficient detoxification of nerve agent simulant in atmospheric environments

We design a spontaneously super-hygroscopic alkaline microreactor by photoinduced integration of Zr-MOF catalyst and alkaline poly(dimethylaminoethyl acrylate) onto LiCl-salinized poly(N-isopropylacrylamide) gel, generating a microenvironment with non-volatile polymeric base and non-bulk water for detoxification of a typical nerve agent simulant, dimethyl 4-nitrophenyl phosphate (DMNP), in atmospheric environments. The super-hygroscopic gel with directional microchannels facilitates the absorption, transport and storage of water under different humidities, and exhibits fast hygroscopic efficiency with a high moisture absorption capacity of 6.4 g g−1. The integrated microreactor achieves simultaneous water uptake and catalytic hydrolysis of DMNP in an atmospheric environment with an initial half-life of ∼1.9 h and a final conversion of 95.5%, which is attributed to the synergistic catalytic microenvironment of the exposed Zr-MOF catalyst, the polymeric base, and the water from moist air. This work provides a feasible strategy for designing spontaneously hygroscopic microreactors for detoxifying nerve agent simulants in atmospheric environments.

Investigation of Thermodynamic Properties of Dimethyl Phosphate-Based ILs for Use as Working Fluids in Absorption Refrigeration Technology.

In the current research, the binary solution containing ionic liquid (IL), 1-ethyl-1-methylmorpholinium dimethyl phosphate ([C1C2MOR][DMP]), 1-ethyl-1-methylpiperidinium dimethyl phosphate ([C1C2PIP][DMP]), or N,N,N-triethyl-N-methylammonium dimethyl phosphate ([N1,2,2,2][DMP]) with ethanol are investigated as new working fluids for absorption refrigeration technology. The IL was mixed with ethanol, which was considered as a refrigerant. Experimental (vapor + liquid) phase equilibria (VLE) of these binary systems were measured by an ebulliometric method within a temperature range from T = (328.15 to 348.15) K with an increment of 10 K and pressures up to 90 kPa. Experimental VLE data were correlated using non-random two-liquid (NRTL) within the maximum average relative deviation of 0.45%, which confirms the effectiveness of using such a model for calculations. Each of the proposed binary systems exhibit a negative deviation from Raoult's law, which is a very important characteristic for working pairs used in absorption heat pumps or absorption refrigerators. From a technological point of view, measurements of physicochemical properties play an important role. In this research, liquid density and dynamic viscosity were determined at temperatures from T = (293.15 to 338.15) K at ambient pressure over the whole concentration range. These properties were correlated using empirical equations. From experimental density data, the excess molar volumes were determined and correlated using the Redlich-Kister type equation. Ionic liquid: [C1C2MOR][DMP] and [C1C2PIP][DMP] were synthesized and characterized using NMR analysis. The thermophysical characterization of pure ILs, including glass transition temperature (Tg) and heat capacity at the glass transition temperature (ΔgCp), was determined using the differential scanning calorimetry technique (DSC) at atmospheric pressure. In this work, the combination of basic studies on the effect of the cation structure of an ionic liquid on the properties of their solutions with ethanol and the possibility of future application of the tested systems in a viable refrigeration system are presented.

1,3-Dimethyl-imidazolium dimethyl phosphate ([MMIM]+[DMP]−) analyzed by XPS and HAXPES

The ionic liquid 1,3-dimethyl-imidazolium-dimethylphosphate ([MMIM]+[DMP]−) was analyzed using (hard) x-ray photoelectron spectroscopy. Here, XPS and HAXPES spectra are shown in comparison. For the acquisition of the XPS spectra, monochromatic Al Kα radiation at 1486.6 eV was used, while for the acquisition of the HAXPES spectra, monochromatic Cr Kα radiation at 5414.8 eV was applied. Here, survey scans and high-resolution spectra of P 2p, P 2s, C 1s, O 1s, and N 1s for both methods and P 1s, P KL2,3L2,3, and P KL1L2,3 for HAXPES are shown.

Simultaneous measurement of trace dimethyl methyl phosphate and temperature using all fiber Michaelson interferometer cascaded FBG.

All fiber Michaelson interferometer cascaded fiber Bragg grating (FBG) sensor for simultaneous measurement of trace dimethyl methyl phosphate and temperature is proposed. One end of the four-core fiber (FCF) is spliced with a multimode fiber (MMF), the other end is flattened and evaporated with silver film to enhance reflection, and the Michelson interference structure is formed. The grating is engraved in the single-mode fiber (SMF) core and spliced with MMF, then the Michelson interference cascaded FBG, FBG-MMF-FCF sensor is obtained. The sensing film, MnCo2O4 is coated on the surface of FCF, and the structure, elemental composition and morphology of MnCo2O4 were analyzed by X-ray diffraction, X-ray photoelectron spectroscopy and scanning electron microscopy. The sensitivity and the detection limit of DMMP are 86.44 dB/ppm and 0.1767 ppb, respectively. The response/recovery time is about 14/10 s. the temperature sensitivity can be compensated and calculated as 0.069 nm/°C. The sensor has good selectivity and stability, and has a good application prospect in high sensitivity detection of trace DMMP vapor.