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Fenton oxidation of 2,4- and 2,6-dinitrotoluene and acetone inhibition

HE Yiliang, ZHAO Bin, HUGHES Joseph B., HAN Sung Soo

《环境科学与工程前沿（英文）》 2008年第2卷第3期页码 326-332 doi: 10.1007/s11783-008-0038-4

摘要： The performances and kinetic parameters of Fenton oxidation of 2,4- and 2,6-dinitrotoluene (DNT) in water-acetone mixtures and explosive contaminated soil washing-out solutions were investigated at a laboratory scale. The experimental results show that acetone can be a significant hydroxyl radical scavenger and result in serious inhibition of Fenton oxidation of 2,4- and 2,6-DNT. Although no serious inhibition was found in contaminated soil washing-out solutions, longer reaction time was needed to remove 2,4- and 2,6-DNT completely, mainly due to the competition of hydroxyl radicals. Fenton oxidation of 2,4- and 2,6-DNT fit well with the first-order kinetics and the presence of acetone also reduced DNT’s degradation kinetics. Based on the comparison and matching of retention time and ultraviolet (UV) spectra between high performance liquid chromatography (HPLC) and standards, the following reaction pathway for 2,4-DNT primary degradation was proposed: 2,4-DNT → 2,4-dinitro-benzaldehyde → 2,4-dinitrobenzoic acid → 1,3-dinitrobenzene → 3-nitrophenol.

关键词： presence 2 4-DNT competition laboratory scavenger

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Sub-cytotoxic concentrations of ionic silver promote the proliferation of human keratinocytes by inducing the production of reactive oxygen species

null

《医学前沿（英文）》 2018年第12卷第3期页码 289-300 doi: 10.1007/s11684-017-0550-7

摘要：

Silver-containing preparations are widely used in the management of skin wounds, but the effects of silver ions on skin wound healing remain poorly understood. This study investigated the effects of silver ions (Ag⁺) on the proliferation of human skin keratinocytes (HaCaT) and the production of intracellular reactive oxygen species (ROS). After treating HaCaT cells with Ag⁺and/or the active oxygen scavenger N-acetyl cysteine (NAC), cell proliferation and intracellular ROS generation were assessed using CCK-8 reagent and DCFH-DA fluorescent probe, respectively. In addition, 5-bromo-2-deoxyUridine (BrdU) incorporation assays, cell cycle flow cytometry, and proliferating cell nuclear antigen (PCNA) immunocytochemistry were conducted to further evaluate the effects of sub-cytotoxic Ag⁺ concentrations on HaCaT cells. The proliferation of HaCaT cells was promoted in the presence of 10⁻⁶ and 10⁻⁵ mol/L Ag⁺ at 24, 48, and 72 h. Intracellular ROS generation also significantly increased for 5–60 min after exposure to Ag⁺. The number of BrdU-positive cells and the presence of PCNA in HaCaT cells increased 48 h after the addition of 10⁻⁶ and 10⁻⁵ mol/L Ag⁺, with 10⁻⁵ mol/L Ag⁺ markedly increasing the cell proliferation index. These effects of sub-cytotoxic Ag⁺ concentrations were repressed by 5 mmol/L NAC. Our results suggest that sub-cytotoxic Ag⁺ concentrations promote the proliferation of human keratinocytes and might be associated with a moderate increase in intracellular ROS levels. This study provides important experimental evidence for developing novel silver-based wound agents or dressings with few or no cytotoxicity.