Objective To examine associations of urinary phthalate levels with blood pressure (BP) and serum triglyceride and lipoprotein levels in children. Study design We performed a cross-sectional analysis ...of a subsample of US children aged 6-19 years who participated in the National Health and Nutrition Examination Survey between 2003 and 2008. We quantified exposure to 3 families of phthalates—low molecular weight, high molecular weight and di-2-ethylhexylphthalate (DEHP)—based on molar concentration of urinary metabolites. We assessed descriptive, bivariate, and multivariate associations with BP and lipid levels. Results Controlling for an array of sociodemographic and behavioral factors, as well as diet and body mass index, levels of metabolites of DEHP, a phthalate commonly found in processed foods, were associated with higher age-, sex-, and height-standardized BP. For each log unit (roughly 3-fold) increase in DEHP metabolites, a 0.041 SD unit increase in systolic BP z -score was identified ( P = .047). Metabolites of low molecular weight phthalates commonly found in cosmetics and personal care products were not associated with BP. Phthalate metabolites were not associated with triglyceride levels, high-density lipoprotein level, or prehypertension. Conclusions Dietary phthalate exposure is associated with higher systolic BP in children and adolescents. Further work is needed to confirm these associations, as well as to evaluate opportunities for intervention.
The nonlinear fluid theory developed by Schamel suggests a modified KdV equation to describe the temporal evolution of ion acoustic (IA) solitons in the presence of trapped electrons. The validity of ...this theory is studied here by verifying solitons' main characteristic, i.e., stability against successive mutual collisions. We have employed a kinetic model as a more comprehensive theory than the fluid one, and utilized a fully kinetic simulation approach (both ions and electrons are treated based on the Vlasov equation). In the simulation approach, these solitons are excited self-consistently by employing the nonlinear process of IA solitons formation from an initial density perturbation (IDP). The effect of the size of IDPs on the chain formation is proved by the simulation code as a benchmark test. It is shown that the IA solitons, in the presence of trapped electrons, can retain their features (both in spatial and velocity direction) after successive mutual collisions. The collisions here include encounters of IA solitons with the same trapping parameter, while differing in size. Kinetic simulation results reveal a complicated behavior during a collision between IA solitons in contrast to the fluid theory predictions and simulations. In the range of parameters considered here, two oppositely propagating solitons rotate around their collective center in the phase space during a collision, independent of their trapping parameters. Furthermore, they exchange some portions of their trapped populations.
Objective To identify the optimal measure of active and passive prenatal tobacco exposure to predict wheeze in early life. Study design We conducted a birth cohort study of 398 mother-infant dyads ...enrolled during the second trimester of pregnancy and followed through age 2 years. We measured tobacco exposure with maternal report, serum cotinine level, and meconium cotinine level. We assessed wheeze with parent report every 6 months. We used a repeated measures logistic regression model. Results Of 367 children with respiratory data, 26% percent had parent reported active or passive prenatal maternal tobacco exposure, but cotinine was detected in 61% of mothers during pregnancy. Compared with children of mothers in the fifth percentile of tobacco exposure, children of mothers in the 95th percentile had increased odds of wheeze when exposure was measured with maternal serum cotinine level (adjusted OR, 2.6; 95% CI, 1.3-5.2; P < .006) versus meconium cotinine level (adjusted OR, 2.0; 95% CI, 1.0-4.0; P = .04) and total parent-reported exposure (adjusted OR, 1.7; 95% CI, 1.1-2.7; P = .01). Conclusions Serum cotinine, a biomarker of tobacco exposure, was more strongly associated with wheeze than parent-reported exposure. Studies that rely on parent report of prenatal tobacco exposure may underestimate risk of wheeze.
Many models of physics beyond the standard model predict the existence of new Abelian forces with new gauge bosons mediating interactions between "dark sectors" and the standard model. We report a ...search for a dark boson Z' coupling only to the second and third generations of leptons in the reaction e super(+) e super(?)arrowrightmu super(+)mu super(?)Z',Z'arrowrightmu super(+) mu? using 514fb super(?1) of data collected by the BABAR experiment. No significant signal is observed for Z' masses in the range 0.212-10 GeV. Limits on the coupling parameter g' as low as 7x10 super(?4) are derived, leading to improvements in the bounds compared to those previously derived from neutrino experiments.
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