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首页> 外文会议>Air Waste Management Association's Annual conference Exhibition >Free Radicals and The Toxicity of Combustion-generated Fine Particles
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Free Radicals and The Toxicity of Combustion-generated Fine Particles

机译：自由基和燃烧产生的细颗粒的毒性

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Exposure to combustion-generated fine particles in the atmosphere kills an estimate of 50,000 people in the USA each year. Combustion source emissions are responsible for as much as 70% of the composition of airborne fine particles. There is considerable debate whether the particles themselves toxic or whether they are carriers for harmful chemicals that are adsorbed on their surface. While it has been known for 50 years that particles contain free radicals, the nature of these radicals and their reactivities are not known and have never been studied in detail. We have found that ambient fine particulate matter (PM_(2.5)) collected at five different cities in the US contains persistent free radicals with electron paramagnetic resonance (EPR) parameters that strikingly resemble those of the semiquinone radicals we have studied in cigarette tar for many years. Many semiquinone radicals undergo redox cycling thereby reducing oxygen and forming cytotoxic reactive oxygen species such as hydrogen peroxide, the superoxide radical anion, and the hydroxyl radical. Aqueous extracts of PM_(2.5) samples induced damage to DNA in human cells. PM_(2.5)-mediated DNA damage was abolished by superoxide dismutase, catalase, and deferoxamine, implicating superoxide radical, hydrogen peroxide, and the hydroxyl radical. Redox cycling by semiquinone radicals are previously unrecognized chemical reactions that may be in part responsible for the toxicity of PM_(2.5).
机译：暴露在大气中燃烧产生的微粒杀死每年5万人在美国的估计。燃烧源排放负责空中微粒的组合物的高达70％。有颗粒是否相当多的争论本身有毒或他们是否为被吸附其表面的有害化学品船。虽然已经知道了50年来的颗粒含有自由基，这些自由基的性质和反应性是不知道，从来没有详细研究。我们发现，周围细颗粒物（PM_（2.5））在美国五个不同的城市收集包含电子顺磁共振（EPR）参数惊人地类似于那些我们在卷烟焦油已经研究了很多半醌自由基的持续自由基年。许多半醌自由基离岗氧化还原循环，从而减少氧气并形成细胞毒性活性氧类物质如过氧化氢，超氧阴离子自由基，和羟基自由基。 PM_的水提取物（2.5）样品诱导的损伤的DNA在人细胞中。 PM_（2.5） - 介导的DNA损伤是由超氧化物歧化酶，过氧化氢酶，和去铁胺废除，暗示超氧过氧化物自由基，氢和羟基自由基。氧化还原由半醌自由基循环是先前未认识到的化学反应，其可以是在负责PM_的毒性（2.5）的一部分。

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