Passive air samplers (PAS) were deployed concurrently at 15 locations (nine urban sites and six rural sites) in Vietnam and exposed for approximately 6 weeks from June 26, 2012 to August 26, 2012 and from December 8, 2012 to February 8, 2013. The concentration, composition and enantiomeric signatures of the target compound and Air Mass Backward Trajectories of the 15 sampling sites are presented and discussed in this study. Relatively clean air mass from ocean and similar concentrations and composition of POPs between the south and north of Vietnam indicate that local emissions is most likely the major source of POPs in Vietnam. Technical DDT and technical HCH were widely used in Vietnam and corresponding quantitative data suggests the sporadic use. The preferential degradation of (+)-α-HCH was found in all sampling sites, which could be a regional characteristic of Vietnam. High trans-/cis-chlordane (TC/CC) ratios indicate the current use of technical chlordane for termite control. PCA estimated that main source of PCBs present in the atmosphere of Vietnam was uncontrolled discarded e-waste.
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http://dx.doi.org/10.1016/j.scitotenv.2015.10.129 | DOI Listing |
Angew Chem Int Ed Engl
November 2024
Beijing National Laboratory for Molecular Sciences, Key Laboratory of Polymer Chemistry and Physics of Ministry of Education, College of Chemical and Molecular Engineering, Peking University, Beijing, 100871, China.
Biological homochirality is a signature of life. Supramolecular polymerization is effective to achieve high hierarchical homochirality in nature, but has not been well-explored. Herein, we report regioselective and homochiral supramolecular polymerization of chiral nanotadpole aggregates made of either synthetic helical poly(phenylacetylene)s or chirality-amplified co-assembly of chiral and achiral poly(phenylacetylene)s.
View Article and Find Full Text PDFFront Oncol
August 2024
Department of Nutritional Sciences, College of Natural Sciences, The University of Texas at Austin, Austin, TX, United States.
Small
December 2024
Molecular Sciences Institute, School of Chemistry, University of the Witwatersrand, Johannesburg, PO Wits. 2050, South Africa.
The designed and ordered co-immobilization of multiple enzymes for vectorial biocatalysis is challenging. Here, a combination of protein phase separation and bioorthogonal linking is used to generate a zeolitic imidazole framework (ZIF-8) containing co-immobilized enzymes. Zn ions induce the clustering of minimal protein modules, such as 6-His tag, proline-rich motif (PRM) and SRC homology 3 (SH3) domains, and allow for phase separation of the coupled aldoketoreductase (AKR) and alcohol dehydrogenase (ADH) at low concentrations.
View Article and Find Full Text PDFChemistry
August 2024
Department of Chemistry, Indian Institute of Science Education and Research Bhopal (IISER Bhopal), Bhopal Bypass Road, 462066, Bhauri, Bhopal, India.
Herein, we designed a chiral, axially-twisted molecular scaffold (ATMS) using pyridine-2,6-dicarboxamide (PDC) unit as pivot, chiral trans-cyclohexanediamine (CHDA) residues as linkers, and pyrene residues as fluorescent reporters. R,R-ATMS exclusively adopted M-helicity and produced differential response in UV-vis, fluorescence, and NMR upon addition of tartaric acid (TA) stereoisomers allowing naked-eye detection and enantiomeric content determination. Circular dichroism (CD) profile of R,R-ATMS underwent unique changes during titration with TA stereoisomers - while loss of CD signal at 345 nm was observed with equimolar D-TA and meso-TA, inversion was seen with equimolar L-TA.
View Article and Find Full Text PDFJ Am Chem Soc
May 2024
Department of Chemistry, Duke University, Durham, North Carolina 27708, United States.
Hydrogel microparticles (HMPs) have been investigated widely for their use in tissue engineering and drug delivery applications. However, translation of these highly tunable systems has been hindered by covalent cross-linking methods within microparticles. Stereocomplexation, a stereospecific form of physical cross-linking, provides a robust yet degradable alternative for creating translationally relevant HMPs.
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