Sex-specific effects of perinatal dioxin exposure on eating behavior in 3-year-old Vietnamese children.

BACKGROUND: We previously reported that perinatal dioxin exposure increased autistic traits in children living in dioxin-contaminated areas of Vietnam. In the present study, we investigated the impact of dioxin exposure on children's eating behavior, which is often altered in those with developmental disorders. METHODS: A total of 185 mother-and-child pairs previously enrolled in a birth cohort in dioxin-contaminated areas participated in this survey, conducted when the children reached 3 years of age. Perinatal dioxin exposure levels in the children were estimated using dioxin levels in maternal breast milk after birth. Mothers were interviewed using the Children's Eating Behaviour Questionnaire (CEBQ). A multiple linear regression model was used to analyze the association between dioxin exposure and CEBQ scores, after controlling for covariates such as location, parity, maternal age, maternal education, maternal body mass index, family income, children's gestational age at delivery, and children's age at the time of the survey. A general linear model was used to analyze the effects of sex and dioxin exposure on CEBQ scores. RESULTS: There was no significant association between most dioxin congeners or toxic equivalencies of polychlorinated dibenzo-p-dioxins/furans (TEQ-PCDDs/Fs) and CEBQ scores in boys, although significant associations between some eating behavior sub-scores and 1,2,3,4,6,7,8,9-octachlorodibenzofuran were observed. In girls, there was a significant inverse association between levels of TEQ-PCDFs and enjoyment of food scores and between levels of TEQ-PCDFs and TEQ-PCDDs/Fs and desire to drink scores. Two pentachlorodibenzofuran congeners and 1,2,3,6,7,8-hexachlorodibenzofuran were associated with a decreased enjoyment of food score, and seven PCDF congeners were associated with a decreased desire to drink score. The adjusted mean enjoyment of food score was significantly lower in children of both sexes exposed to high levels of TEQ-PCDFs. There was, however, a significant interaction between sex and TEQ-PCDF exposure in their effect on desire to drink scores, especially in girls. CONCLUSIONS: Perinatal exposure to dioxin can influence eating behavior in children and particularly in girls. A longer follow-up study would be required to assess whether emotional development that affects eating styles and behaviors is related to dioxin exposure.

Controlled synthesis of trimetallic nitrogen-incorporated CoNiFe layered double hydroxide electrocatalysts for boosting the oxygen evolution reaction.

The development of non-precious trimetallic electrocatalysts exhibiting high activity and stability is a promising strategy for fabricating efficient electrocatalysts for the oxygen evolution reaction (OER). In this study, trimetallic nitrogen-incorporated CoNiFe (N-CoNiFe) was produced to solve the low OER efficiency using a facile co-precipitation method in the presence of ethanolamine (EA) ligands. A series of CoNiFe catalysts at different EA concentrations were also investigated to determine the effects of the ligand in the co-precipitation of a trimetallic system. The introduction of an optimized EA concentration (20 mM) improved the electrocatalytic performance of N-CoNiFe dramatically, with an overpotential of 318 mV at 10 mA cm-2 in 1.0 M KOH and a Tafel slope of 72.2 mV dec-1. In addition, N-CoNiFe shows high durability in the OER process with little change in the overpotential (ca. 16.0 mV) at 10 mA cm-2 after 2000 cycles, which was smaller than that for commercial Ir/C (38.0 mV).

All carbon hybrid N-doped carbon dots/carbon nanotube structures as an efficient catalyst for the oxygen reduction reaction.

This paper reports the facile and scalable synthesis of hybrid N-doped carbon quantum dots/multi-walled carbon nanotube (CD/CNT) composites, which are efficient alternative catalysts for the oxygen reduction reaction (ORR) in fuel cells. The N-doped CDs for large-scale production were obtained within 5 minutes via a one-step polyol process using ethylenediamine (ED) in the presence of hydrogen peroxide as an oxidizing agent. For comparison, different CDs were also prepared using ethylene glycol (EG) and ethanolamine (EA) in the same manner. Physicochemical characterization suggested the successful formation of a CD(ED)/CNT hybrid without individual CD(ED)s and CNTs. The N-doped CD(ED)/CNT catalyst exhibited excellent electrocatalytic activity in an alkaline solution compared to other composites (CD(EG)/CNT and CD(EA)/CNT). The Tafel slope (-60.9 mV dec-1) and durability (∼9.1% decay over 10 h) for CD(ED)/CNT were superior to high-performance Pt/C catalysts. The electrochemical double-layer capacitance on the CD(ED)/CNT hybrid showed apparent improvement of the active surface area because of N-doping and highly decorated CDs on the CNT wall. These results provide an innovative approach for the potential application of all carbon hybrid structures in electrocatalysis.

Impacts of Perinatal Dioxin Exposure on Motor Coordination and Higher Cognitive Development in Vietnamese Preschool Children: A Five-Year Follow-Up.

Dioxin concentrations remain elevated in the environment and in humans residing near former US Air Force bases in South Vietnam. Our previous epidemiological studies showed adverse effects of dioxin exposure on neurodevelopment for the first 3 years of life. Subsequently, we extended the follow-up period and investigated the influence of perinatal dioxin exposure on neurodevelopment, including motor coordination and higher cognitive ability, in preschool children. Presently, we investigated 176 children in a hot spot of dioxin contamination who were followed up from birth until 5 years old. Perinatal dioxin exposure levels were estimated by measuring dioxin levels in maternal breast milk. Dioxin toxicity was evaluated using two indices; toxic equivalent (TEQ)-polychlorinated dibenzo-p-dioxins/furans (PCDDs/Fs) and concentration of 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD). Coordinated movements, including manual dexterity, aiming and catching, and balance, were assessed using the Movement Assessment Battery for Children, Second Edition (Movement ABC-2). Cognitive ability was assessed using the nonverbal index (NVI) of the Kaufman Assessment Battery for Children, Second Edition (KABC-II). In boys, total test and balance scores of Movement ABC-2 were significantly lower in the high TEQ- PCDDs/Fs group compared with the moderate and low exposure groups. NVI scores and the pattern reasoning subscale of the KABC-II indicating planning ability were also significantly lower in the high TCDD exposure group compared with the low exposure group of boys. However, in girls, no significant differences in Movement ABC-2 and KABC-II scores were found among the different TEQ-PCDDs/Fs and TCDD exposure groups. Furthermore, in high risk cases, five boys and one girl highly exposed to TEQ-PCDDs/Fs and TCDD had double the risk for difficulties in both neurodevelopmental skills. These results suggest differential impacts of TEQ-PCDDs/Fs and TCDD exposure on motor coordination and higher cognitive ability, respectively. Moreover, high TEQ-PCDDs/Fs exposure combined with high TCDD exposure may increase autistic traits combined with developmental coordination disorder.

Perinatal dioxin exposure and the neurodevelopment of Vietnamese toddlers at 1 year of age.

Dioxin concentrations remain elevated in both the environment and in humans residing near former US Air Force bases in South Vietnam. This may potentially have adverse health effects, particularly on infant neurodevelopment. We followed 214 infants whose mothers resided in a dioxin-contaminated area in Da Nang, Vietnam, from birth until 1 year of age. Perinatal exposure to dioxins was estimated from toxic equivalent (TEQ) levels of polychlorinated dibenzodioxins and polychlorinated dibenzofurans (PCDDs/Fs-TEQ), and 2,3,7,8-tetrachlorodibenzo-p-dioxin (2,3,7,8-TetraCDD) concentrations in breast milk. In infants, daily dioxin intake (DDI) was used as an index of postnatal exposure through breastfeeding. Neurodevelopment of toddlers was assessed using the Bayley Scales of Infant and Toddler Development, Third Edition (Bayley-III). No significant differences in neurodevelopmental scores were exhibited for cognitive, language or motor functions between four exposure groups of PCDDs/Fs-TEQ or 2,3,7,8-TetraCDD. However, social-emotional scores were decreased in the high PCDDs/Fs-TEQ group and the high 2,3,7,8-TetraCDD group compared with those with mild exposure, after adjusting for confounding factors. Cognitive scores in the mild, moderate, and high DDI groups were significantly higher than those in low DDI group, but there were no differences in cognitive scores among the three higher DDI groups. These results suggest that perinatal exposure to dioxins may affect social-emotional development of 1-year-old toddlers, without diminishing global neurodevelopmental function.