Three modes in a radio frequency atmospheric pressure glow discharge

Shi, Jian; Deng, X.T.; Hall, Robert H.; Punnett, J.D.; Kong, Michael G.

doi:10.1063/1.1622110

Cited by 117 publications

(110 citation statements)

References 25 publications

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“…It is possible to reduce this further using, for example, different gases, 6,7,20 different temporal features of the electrical excitation, 10,18,22 and indeed different APGD configurations. 5,23 A related issue is whether a minimum protein residue of 7.1 femtomoles/ mm 2 is acceptable for plasma-treated surgical instruments to be reused, and indeed what the acceptable minimum of protein residue may be. At present, these questions remain unanswered and the ultimate answer lies in a thorough bioassay study.…”

Section: Plasma Conditions For Effective Protein Reductionmentioning

confidence: 99%

Protein destruction by a helium atmospheric pressure glow discharge: Capability and mechanisms

Deng

Shi

Kong

2007

Journal of Applied Physics

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171

108

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Citation: DENG X.T., SHI, J.J. and KONG, M.G., 2007. Protein destruction by a helium atmospheric pressure glow discharge: capability and mechanisms.Journal of Applied Physics, 101 (7), article 074701, pp.1-9.Additional Information:• Biological sterilization represents one of the most exciting applications of atmospheric pressure glow discharges ͑APGD͒. Despite the fact that surgical instruments are contaminated by both microorganisms and proteinaceous matters, sterilization effects of APGD have so far been studied almost exclusively for microbial inactivation. This work presents the results of a detailed investigation of the capability of a helium-oxygen APGD to inactivate proteins deposited on stainless-steel surfaces. Using a laser-induced fluorescence technique for surface protein measurement, a maximum protein reduction of 4.5 logs is achieved by varying the amount of the oxygen admixture into the background helium gas. This corresponds to a minimum surface protein of 0.36 femtomole/ mm 2 . It is found that plasma reduction of surface-borne protein is through protein destruction and degradation, and that its typically biphasic reduction kinetics is influenced largely by the thickness profile of the surface protein. Also presented is a complementary study of possible APGD protein inactivation mechanisms. By interplaying the protein inactivation kinetics with optical emission spectroscopy, it is shown that the main protein-destructing agents are excited atomic oxygen ͑via the 777 and 844 nm emission channels͒ and excited nitride oxide ͑via the 226, 236, and 246 nm emission channels͒. It is also demonstrated that the most effective protein reduction is achieved possibly through a synergistic effect between atomic oxygen and nitride oxide. This study is a useful step toward a full confirmation of the efficacy of APGD as a sterilization technology for surgical instruments contaminated by prion proteins.

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Section: Plasma Conditions For Effective Protein Reductionmentioning

confidence: 99%

Protein destruction by a helium atmospheric pressure glow discharge: Capability and mechanisms

Deng

Shi

Kong

2007

Journal of Applied Physics

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171

108

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“…One of the most widely used APP applicators is the tube design which includes: the plasma jet [4,5], plasma needle [6], plasma pencil [7], and microplasma jet [8]. The plasma operational modes of these tube sources are influenced by their electrode configuration, gas flow rate, gas type, applied power and the distance between the plasma applicator nozzle and treated surface [9][10][11]. This study is focused on the examination of an industrial scale low temperature atmospheric plasma jet system called PlasmaStream TM [12,13].…”

Section: Introductionmentioning

confidence: 99%

Electrical, Thermal and Optical Diagnostics of an Atmospheric Plasma Jet System

Nwankire

Law

Nindrayog³

et al. 2010

Plasma Chem Plasma Process

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Plasma diagnostics of atmospheric plasmas is a key tool in helping to understand processing performance issues. This paper presents an electrical, optical and thermographic imaging study of the PlasmaStream atmospheric plasma jet system. The system was found to exhibit three operating modes; one constricted/localized plasma and two extended volume plasmas. At low power and helium flows the plasma is localized at the electrodes and has the electrical properties of a corona/filamentary discharge with electrical chaotic temporal structure. With increasing discharge power and helium flow the plasma expands into the volume of the tube, becoming regular and homogeneous in appearance. Emission spectra show evidence of atomic oxygen, nitric oxide and the hydroxyl radical production. Plasma activated gas temperature deduced from the rotational temperature of nitrogen molecules was found to be of order of 400 K: whereas thermographic imaging of the quartz tube yielded surface temperatures between 319 and 347 K.

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“…[1][2][3] They are usually generated between two parallel electrodes and at an excitation frequency either in the kilohertz range ͑1-100 kHz͒ 1,4,5 or in the radio-frequency ͑rf͒ range ͑1-100 MHz͒. [6][7][8][9][10] Their electron mean-free path is typically in the region of a few submillimeters, thus making it difficult to maintain plasma stability when their volume is increased to cater to industrial applications. To prevent APGDs from evolving into arc plasmas, a common strategy is to keep their operation well within their stability range by decreasing the discharge current.…”

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confidence: 99%