53 research outputs found

    Photodegradation of Polyfluorinated Dibenzo‑<i>p</i>‑Dioxins in Organic Solvents: Experimental and Theoretical Studies

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    Eighteen polyfluorinated dibenzo-<i>p</i>-dioxins (PFDDs) were synthesized by pyrolysis of fluorophenols. Using a 500 W Xe lamp as the light source, the PFDDs photodegradation kinetics in <i>n</i>-hexane were investigated. The photolysis reactions obeyed the pseudo-first-order rate equation, and higher fluorinated PFDDs tended to photolyze more slowly. Theoretically calculated parameters reflecting the molecular structural properties were used to develop a new model of PFDDs photolysis rates. The results indicated that the substitution pattern for fluorine atoms and the C–O bond length were major factors in the photolysis of PFDDs. We selected octafluorinated dibenzo-<i>p</i>-dioxin (OFDD) as a representative PFDDs to explore the influence of solvent on the photolysis rate of PFDDs, and the results indicated that neither the polarity nor donor hydrogen of organic solvents are independent influencing factors. Mechanistic pathways for the photolysis of OFDD in <i>n</i>-hexane were first studied. The results indicated that photodegradation of OFDD produces octafluorinated dihydroxybiphenyls, octafluorinated phenoxyphenols, and fluorinated phenols. The major pathway for photodegradation of OFDD was C–O bond cleavage. Defluorination reactions did not occur during the photolysis process

    3D initial surface (tooth in volume rendering).

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    <p>(a), (b) and (c) stand for different 3D perspective, respectively.</p

    Additional file 1 of cgMSI: pathogen detection within species from nanopore metagenomic sequencing data

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    Additional file 1: contains a supplementary table on software information used in performance evaluation, and supplementary figures on quality control results for simulated samples, and the results of Salmonella enterica detection using cgMSI

    The flowchart of the proposed framework for volume calculation from MicroCT images.

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    <p><i>m</i> is the number of points inside target region; <i>N</i> is the number of random points generated; <i>S</i><sub><i>N</i></sub> is the area of N-th slice of MicroCT scan; and <i>S</i><sub><i>i</i></sub> is the area of target region for each slice.</p

    Proposed reaction pathways of TBBPA ozonation.

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    <p>Molecular ion clusters observed in MS spectra for the identified products are given below their respective structures. Possible transformation of inorganic bromine species was shown in green dash line box.</p
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