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DDC: 540 × Publisher: New York, NY [u.a.] : Hindawi ×

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    Evaluation of Sonocatalytic and Photocatalytic Processes Efficiency for Degradation of Humic Compounds Using Synthesized Transition-Metal-Doped ZnO Nanoparticles in Aqueous Solution
    (New York, NY [u.a.] : Hindawi, 2021) Maleki, Afshin; Seifi, Mehran; Marzban, Nader
    The existence of a humic substance in water causes the growth of microorganisms and reduces the quality of water; therefore, the removal of these materials is crucial. Here, the ZnO nanoparticles doped using transition metals, copper (Cu) and manganese (Mn), were used as an effective catalyst for photocatalytic removal of humic substances in an aqueous environment under ultraviolet, visible light, and light-emitting diode irradiations. Also, we study the effect of the sonocatalytic method. A solvothermal procedure is used for doping, and the Cu- and Mn-doped ZnO nanocatalyst were characterized by means of FTIR, XRD, AFM, SEM, and EDAX analyses. We investigate the effect of operational variables, including doping ratio, initial pH, catalyst dose, initial HS content, and illuminance on the removal efficiency of the processes. The findings of the analyses used for the characterization of the nanoparticles illustrate the appropriate synthesis of the Cu- and Mn-doped ZnO nanocatalysts. We observe the highest removal efficiency rate under acidic conditions and the process efficiency decreased with increasing solution pH, when we tested it in the range of 3–7. Photocatalytic decomposition of HS increases with a rise in catalyst dose, but an increase in initial HS content results in decreasing the removal efficiency. We observe the highest photocatalytic degradation of humic acid while using the visible light, and the highest removal efficiency is obtained using Cu.ZnO. The Cu.ZnO also shows better performance under ultraviolet irradiation compared to other agents.
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    Synthesis and Biological Evaluation of New (−)-Gossypol-Derived Schiff Bases and Hydrazones
    (New York, NY [u.a.] : Hindawi, 2017) Vu, Vu Van; Nhung, Trinh Thi; Thanh, Nguyen Thi; Chinh, Luu Van; Tien, Vu Dinh; Thuy, Vu Thu; Thi Thao, Do; Nam, Nguyen Hai; Koeckritz, Angela; Vu, Tran Khac
    A series of 14 new (-)-gossypol Schiff bases and hydrazones have been synthesized via an in situ procedure in high yields. Structural data showed that all target compounds exist as the enamine tautomer. Bioassays showed that several compounds exhibited cytotoxic effects against three human cancer cell lines. Compound 8a showed the greatest cytotoxic effect against hepatocellular carcinoma (HepG2), lung carcinoma (LU-1), and breast cancer (MCF-7) cell lines with IC50 values of 20.93, 13.58, and 9.40 μM, respectively. However, in an antibacterial test, compounds 8a and 8b inhibited Staphylococcus aureus and Bacillus cereus and compound 8e inhibited only Staphylococcus aureus at the same MIC values of 1024 μg/ml.
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    Catalytic β-Bromohydroxylation of Natural Terpenes: Useful Intermediates for the Synthesis of Terpenic Epoxides
    (New York, NY [u.a.] : Hindawi, 2018) Oubaassine, Saadia; Köckritz, Angela; Eckelt, Reinhard; Martin, Andreas; Ait Ali, Mustapha; El Firdoussi, Larbi
    In a one-step procedure, various ß-bromoalcohols were synthesized from natural terpenes in good to excellent yields. Using different catalysts, the reaction was carried out at room temperature, with H 2 O as nucleophile and N-bromosuccinimide as a bromine source under mild reaction conditions. The synthesized ß-bromoalcohols were subsequently converted in situ to the corresponding epoxides in good yields. © 2019 Saadia Oubaassine et al.