Polybrominated diphenyl ethers (PBDEs), a group of persistent organic pollutants (POPs), are caused for concern recently due to their adverse health effects and environmental ubiquity. In this study, atmospheric and soil PBDE levels in Taizhou, one of the largest WEEE dismantling areas in the world, were measured, ranging from 884 to 2791 pg m− 3 with an average of 1968 pg m− 3 for atmosphere and 2.96 to 200 ng g− 1 dry weight (dw) with the mean of 65.2 ng g− 1 dw for farmland soils, respectively. The close connection between soil PBDE accumulation and atmospheric deposition was also revealed by the estimation of the annual PBDE deposition flux (3.1 ± 0.9 mg m− 2 a− 1) and the similarity between deposited congener pattern and soil congener profile. Positive matrix factorization (PMF) was conducted to extract possible sources of farmland soil PBDEs and to calculate their contributions. Based on the measured source profiles of PBDE-related activities, five sources were identified representing WEEE dumping, WEEE dismantling, WEEE open burning, residential waste dismantling, and residential waste open burning. WEEE-related recycling activities contributed primary percentage (52%) to farmland soil PBDE concentration, and open burning was an important pathway for PBDEs entering the environment.
Polybrominated diphenyl ethers (PBDEs), a group of persistent organic pollutants (POPs), are caused for concern recently due to their adverse health effects and environmental ubiquity. In this study, atmospheric and soil PBDE levels in Taizhou, one of the largest WEEE dismantling areas in the world, were measured, ranging from 884 to 2791 pg m(-3) with an average of 1968 pg m(-3) for atmosphere and 2.96 to 200 ng g(-1) dry weight (dw) with the mean of 65.2 ng g(-1) dw for farmland soils, respectively. The close connection between soil PBDE accumulation and atmospheric deposition was also revealed by the estimation of the annual PBDE deposition flux (3.1 +/- 0.9 mg m(-2) a(-1)) and the similarity between deposited congener pattern and soil congener profile. Positive matrix factorization (PMF) was conducted to extract possible sources of farmland soil PBDEs and to calculate their contributions. Based on the measured source profiles of PBDE-related activities, five sources were identified representing WEEE dumping, WEEE dismantling, WEEE open burning, residential waste dismantling, and residential waste open burning. WEEE-related recycling activities contributed primary percentage (52%) to farmland soil PBDE concentration, and open burning was an important pathway for PBDEs entering the environment. (C) 2013 Elsevier B.V. All rights reserved.
Postzygotic single-nucleotide mutations (pSNMs) have been studied in cancer and a few other overgrowth human disorders at whole-genome scale and found to play critical roles. However, in clinically unremarkable individuals, pSNMs have never been identified at whole-genome scale largely due to technical difficulties and lack of matched control tissue samples, and thus the genome-wide characteristics of pSNMs remain unknown. We developed a new Bayesian-based mosaic genotyper and a series of effective error filters, using which we were able to identify 17 SNM sites from ∼80× whole-genome sequencing of peripheral blood DNAs from three clinically unremarkable adults. The pSNMs were thoroughly validated using pyrosequencing, Sanger sequencing of individual cloned fragments, and multiplex ligation-dependent probe amplification. The mutant allele fraction ranged from 5%-31%. We found that C→T and C→A were the predominant types of postzygotic mutations, similar to the somatic mutation profile in tumor tissues. Simulation data showed that the overall mutation rate was an order of magnitude lower than that in cancer. We detected varied allele fractions of the pSNMs among multiple samples obtained from the same individuals, including blood, saliva, hair follicle, buccal mucosa, urine, and semen samples, indicating that pSNMs could affect multiple sources of somatic cells as well as germ cells. Two of the adults have children who were diagnosed with Dravet syndrome. We identified two non-synonymous pSNMs in SCN1A, a causal gene for Dravet syndrome, from these two unrelated adults and found that the mutant alleles were transmitted to their children, highlighting the clinical importance of detecting pSNMs in genetic counseling.
A series of aromatic amides incorporated with N-heterocycles or triptycene units are synthesized and studied for probing the effects of such chemical modifications on the intermolecular interactions. Single crystals of a number of heterocyclic amides and the triptycene-containing amide were obtained. Crystal structures, hydrogen bonds, lattice energy, solubility, and melting points were compared amongst relevant molecules. Suitably positioned nitrogen atoms from heterocycles are found to form intramolecular H-bonds with amide NHs at the expense of weakening or disrupting the intermolecular H-bonds. The effects of such H-bonding changes on solubility and melting point are nonetheless limited. Uniquely, the triptycene unit effectively improves the solubility of the amide without tempering the thermal resistance of the molecule.