7 research outputs found

    Perfluoroalkyl and polyfluoroalkyl substances in the lower atmosphere and surface waters of the Chinese Bohai Sea, Yellow Sea, and Yangtze River estuary

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    Polyfluoroalkyl and perfluoroalkyl substances (PFASs), in the forms of neutral polyfluoroalkyl substances in the gas phase of air and ionic perfluoroalkyl substances in the dissolved phase of surface water, were investigated during a sampling campaign in the Bohai Sea, Yellow Sea, and Yangtze River estuary in May 2012. In the gas phase, the concentrations of neutral Sigma PFASs were within the range of 76-551 pg/m(3). Higher concentrations were observed in the South Yellow Sea. 8:2 fluorotelomer alcohol (FTOH) was the predominant compound as it accounted for 92%-95% of neutral Sigma PFASs in all air samples. Air mass backward trajectory analysis indicated that neutral Sigma PFASs came mainly from the coast of the Yellow Sea, including the Shandong, Jiangsu, and Zhejiang provinces of China, and the coastal region of South Korea. The fluxes of gas phase dry deposition, were simulated for neutral PFASs, and neutral Sigma PFASs fluxes varied from 0.37 to 23 pg/m(2)/s. In the dissolved phase of the surface water, concentrations of ionic Sigma PFASs ranged from 1.6 to 118 ng/L, with the Bohai Sea exhibiting higher concentrations than both the Yellow Sea and the Yangtze River estuary. Perfluorooctanoic acid (PFOA) was the predominant compound accounting for 51%-90% of the ionic Sigma PFAS concentrations. Releases from industrial and domestic activities as well as the semiclosed geographical conditions increased the level of ionic Sigma PFASs in the Bohai Sea. The spatial distributions of perfluoroalkyl carboxylic acids (PFCAs) and perfluoroalkane sulfonic acids (PFSAs) were different significantly. The Laizhou Bay was the major source region of PFCAs and the Yangtze River estuary was the major source of PFSAs. (C) 2017 Elsevier B.V. All rights reserved

    Price-and-Time-Aware Dynamic Ridesharing

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    Characteristics and serological patterns of COVID

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    The lack of effective treatments against the 2019 coronavirus disease (COVID-19) has led to the exploratory use of convalescent plasma for treating COVID-19. Case reports and case series have shown encouraging results. This study investigated SARS-CoV-2 antibodies and epidemiological characteristics in convalescent plasma donors, to identify criteria for donor selection. Recovered COVID-19 patients, aged 18-55 years, who had experienced no symptoms for more than 2 weeks, were recruited. Donor characteristics such as disease presentations were collected and SARS-CoV-2 N-specific IgM, IgG, and S-RBD-specific IgG levels were measured by enzyme-linked immunosorbent assay (ELISA). Whereas levels of N-specific IgM antibody declined after recovery, S-RBD-specific and N-specific IgG antibodies increased after 4 weeks from the onset of symptoms, with no significant correlation to age, sex, or ABO blood type. Donors with the disease presentation of fever exceeding 38.5°C or lasting longer than 3 days exhibited higher levels of S-RBD-specific IgG antibodies at the time of donation. Of the 49 convalescent plasma donors, 90% had an S-RBD-specific IgG titer of ≥1:160 and 78% had a titer of ≥1:640 at the time of plasma donation. Of the 30 convalescent plasma donors, who had donated plasma later than 28 days after the onset of symptoms and had a disease presentation of fever lasting longer than 3 days or a body temperature exceeding 38.5°C, 100% had an S-RBD-specific IgG titer of ≥1:160 and 93% had a titer of ≥1:640. This study indicates that the S-RBD-specific IgG antibody reaches higher levels after 4 weeks from the onset of COVID-19 symptoms. We recommend the following selection criteria for optimal donation of COVID-19 convalescent plasma: 28 days after the onset of symptoms and with a disease presentation of fever lasting longer than 3 days or a body temperature exceeding 38.5°C. Selection based on these criteria can ensure a high likelihood of achieving sufficiently high S-RBD-specific IgG titers
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