Laser Scattering Diagnosis of a 60-Hz Non-Equilibrium Atmospheric Pressure Plasma Jet

Jia, Feng-Dong; Sumi, Naoya; Ishikawa, Kenji; Kano, Hiroyuki; Inui, Hirotoshi; Kularatne, Jagath; Takeda, Keigo; Kondo, Hiroki; Sekine, Makoto; Kono, Akihiro; Hori, Masaru

doi:10.1143/apex.4.026101

Cited by 40 publications

(40 citation statements)

References 24 publications

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“…Discharge conditions were in argon gas (2 standard liters/min; slm) excited by applying 10 kV of a 60-Hz commercial power supply to two electrodes with a distance of 8 mm [16]. In brief, NEAPP with an ultra-high electron density (approximately 2×10 16 cm −3 ) provided characteristically with an ultra-high O density estimated of around 4×10 15 cm −3 [22], [23]. Furthermore, generation of reactive oxygen species (ROS), such as hydroxyl radicals, singlet oxygen radicals, nitrogen oxide, and nitrogen, were confirmed by optical emission spectroscopy (OES).…”

Section: Methodsmentioning

confidence: 99%

Effect of Indirect Nonequilibrium Atmospheric Pressure Plasma on Anti-Proliferative Activity against Chronic Chemo-Resistant Ovarian Cancer Cells In Vitro and In Vivo

et al. 2013

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PurposeNonequilibrium atmospheric pressure plasma (NEAPP) therapy has recently been focused on as a novel medical practice. Using cells with acquired paclitaxel/cisplatin resistance, we elucidated effects of indirect NEAPP-activated medium (NEAPP-AM) exposure on cell viability and tumor growth in vitro and in vivo.MethodsUsing chronic paclitaxel/cisplatin-resistant ovarian cancer cells, we applied indirect NEAPP-exposed medium to cells and xenografted tumors in a mouse model. Furthermore, we examined the role of reactive oxygen species (ROS) or their scavengers in the above-mentioned EOC cells.ResultsWe assessed the viability of NOS2 and NOS3 cells exposed to NEAPP-AM, which was prepared beforehand by irradiation with NEAPP for the indicated time. In NOS2 cells, viability decreased by approximately 30% after NEAPP-AM 120-sec treatment (P<0.01). The growth-inhibitory effects of NEAPP-AM were completely inhibited by N-acetyl cysteine treatment, while L-buthionine-[S, R]-sulfoximine, an inhibitor of the ROS scavenger used with NEAPP-AM, decreased cell viability by 85% after NEAPP-AM 60-sec treatment(P<0.05) and by 52% after 120 sec, compared to the control (P<0.01). In the murine subcutaneous tumor-formation model, NEAPP-AM injection resulted in an average inhibition of the NOS2 cell-inoculated tumor by 66% (P<0.05) and NOS2TR cell-inoculated tumor by 52% (P<0.05), as compared with the control.ConclusionWe demonstrated that plasma-activated medium also had an anti-tumor effect on chemo-resistant cells in vitro and in vivo. Indirect plasma therapy is a promising treatment option for EOC and may contribute to a better patient prognosis in the future.

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Section: Methodsmentioning

confidence: 99%

Effect of Indirect Nonequilibrium Atmospheric Pressure Plasma on Anti-Proliferative Activity against Chronic Chemo-Resistant Ovarian Cancer Cells In Vitro and In Vivo

et al. 2013

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“…Among various methods for producing atmospheric-pressure plasmas in contact with liquids [7][8][9][10][11][12][13][14][15][16][17][18], in this work, we have employed dc glow discharge between a nozzle electrode and an electrolyte, which has been reported by Shirai and coworkers [19][20][21][22]. A reason for choosing this plasma source is that it can produce a stable positive column with a cathode sheath [23].…”

Section: Introductionmentioning

confidence: 99%

Density distributions of OH, Na, water vapor, and water mist in atmospheric-pressure dc helium glow plasmas in contact with NaCl solution

Sasaki

Ishigame

Nishiyama

2015

Eur. Phys. J. Appl. Phys.

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Abstract. This paper reports the density distributions of OH, Na, water vapor and water mist in atmospheric-pressure dc helium glow plasmas in contact with NaCl solution. The densities of OH, Na and H2O had different spatial distributions, while the Na density had a similar distribution to mist, suggesting that mist is the source of Na in the gas phase. When the flow rate of helium toward the electrolyte surface was increased, the distributions of all the species densities concentrated in the neighboring region to the electrolyte surface more significantly. The densities of all the species were sensitive to the electric polarity of the power supply. In particular, we never detected Na and mist when the electrolyte worked as the anode of the dc discharge.

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“…The electron density of the NEAPP was approximately 10 15 cm -3 for Ar gas flow rate of 2 slm, as determined from laser Thomson scattering in Ref. 42. It led to the generation of high-density reactive species.…”

Section: Methodsmentioning

confidence: 87%

“…The Ar gas of 3 slm flowed into the discharge region through a gas tube having an inner diameter of 2 mm. A 60 Hz power supply offers advantages, such as a reduction in the size of the plasma source, the generation of a plasma with a high density, and convenient use in various fields [41,42]. The electron density of the NEAPP was approximately 10 15 cm -3 for Ar gas flow rate of 2 slm, as determined from laser Thomson scattering in Ref.…”

Section: Methodsmentioning

confidence: 99%

Plasma agriculture based on quantitative monitoring of reactions between fungal cells and atmospheric-pressure plasmas

2012

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A high-density non-equilibrium atmospheric pressure plasma (NEAPP) applied for inactivating fungal spores of P. digitatum is introduced as an environmentally safe and rapidinactivation method. The contributions of ozone, ultra violet (UV) radiation and ground-state atomic oxygen in the NEAPP on the inactivation of the spores are evaluated using colony count method.The absolute densities of ozone were measured by using ultraviolet absorption spectroscopy. The ozone density increased from 2 to 8 ppm with an increase in the distance from the plasma source, while the inactivation rate decreased. The inactivation rate of plasma was evaluated to be thousand times higher than that of an ozone generator using the integrated number density of ozone. In addition, it was clarified that the contribution of UV radiation to inactivation was not dominant for P. digitatum inactivation by NEAPP by filtering the active species using quartz plate. From these results, we can speculate that the inactivation efficiency of reactive oxygen species (ROS) will be larger than those of others.In order to investigate the effect of ground-state atomic oxygen as one of ROS, the inactivation of P. digitatum spores using an oxygen radical source that employs a high-density atmospheric-pressure O 2 /Ar plasma. The absolute O density was measured to be 1.4×10 14 and 1.5×10 15 cm -3 using vacuum ultra violet absorption spectroscopy (VUVAS) using a microdischarge hollow cathode lamp. The behaviors of the O densities as a function of O 2 /(Ar+O 2 ) mixture flow rate ratio correspond to that of the inactivation rate. This result indicates that ground-state atomic oxygen is concluded to be the dominant species that causes inactivation.

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Laser Scattering Diagnosis of a 60-Hz Non-Equilibrium Atmospheric Pressure Plasma Jet

Cited by 40 publications

References 24 publications

Effect of Indirect Nonequilibrium Atmospheric Pressure Plasma on Anti-Proliferative Activity against Chronic Chemo-Resistant Ovarian Cancer Cells In Vitro and In Vivo

Effect of Indirect Nonequilibrium Atmospheric Pressure Plasma on Anti-Proliferative Activity against Chronic Chemo-Resistant Ovarian Cancer Cells In Vitro and In Vivo

Density distributions of OH, Na, water vapor, and water mist in atmospheric-pressure dc helium glow plasmas in contact with NaCl solution

Plasma agriculture based on quantitative monitoring of reactions between fungal cells and atmospheric-pressure plasmas

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