Evaluation of the roles of reactive species, heat, and UV radiation in the inactivation of bacterial cells by air plasmas at atmospheric pressure

2004 ◽  
Vol 233 (1-3) ◽  
pp. 81-86 ◽  
Author(s):  
M. Laroussi ◽  
F. Leipold
Keyword(s):  
Uv Radiation ◽  
Atmospheric Pressure ◽  
Reactive Species ◽  
Bacterial Cells ◽  
Air Plasmas

Reactive species in cold atmospheric-pressure He+Air plasmas: The influence of humidity

2019 ◽  
Vol 26 (6) ◽  
pp. 063514 ◽  
Author(s):  
Bowen Sun ◽  
Dingxin Liu ◽  
Xiaohua Wang ◽  
Zhichao Liu ◽  
Felipe Iza ◽  
...  
Keyword(s):  
Atmospheric Pressure ◽  
Reactive Species ◽  
Air Plasmas

UV ability to inactivate microorganisms combined with factors affecting radiation

1997 ◽  
Vol 35 (11-12) ◽  
pp. 107-112 ◽  
Author(s):  
A. M. Shaban ◽  
G. E. El-Taweel ◽  
G. H. Ali
Keyword(s):  
Microbial Communities ◽  
Uv Radiation ◽  
Contact Time ◽  
Tap Water ◽  
Scenedesmus Obliquus ◽  
Morphological Characters ◽  
The Other ◽  
Bacterial Cells ◽  
Dark Repair ◽  
Nile Water

In the present study, the effect of UV radiation on the inactivation of a range of microorganisms was studied. Each organism was seeded into sterile tap water and exposed to UV in batch experiments with changing turbidities. In addition, the effect of UV on microbial communities in river Nile water was examined. It was found that 1min contact time (0.5L/min flow rate) was effective against vegetative cells levels almost reaching zero (except with Staphylococcus aureus). On the other hand, spore-forming bacteria, Candida albicans and coliphage were more resistant to UV. This contact time caused coenobia cells in single form with Scenedesmus obliquus while for Microcystis aeruginosa colonies broke into smaller groups. Exposure of Nile water microbial communities to UV showed that yeasts and Aeromonas survived better than the other organisms while in the phytoplankton partial fragmentation occurred in some algal groups. The protective effect of turbidity differed between organisms, with increased contact time under conditions of stable turbidity having no effect on the organisms. At 20 NTU the UV radiation had no effect on the morphological characters of algal cells. In reactivation experiments, it is clear that photoreactivation, and not dark repair, takes place with bacterial cells. Only coliphage had no photoreactivation and dark repair responses although with coliphage and host, both reactivation processes worked well. Moreover, the irradiated algae regained their normal shape after 3 days in suitable media and enough light.

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

2012 ◽  
Vol 1469 ◽  
Author(s):  
Masafumi Ito ◽  
Takayuki Ohta ◽  
Keigo Takeda
Keyword(s):  
Uv Radiation ◽  
Absorption Spectroscopy ◽  
Ground State ◽  
Atmospheric Pressure ◽  
Atomic Oxygen ◽  
Fungal Spores ◽  
Ultra Violet ◽  
High Density ◽  
Inactivation Rate ◽  
The Absolute

ABSTRACTA high-density non-equilibrium atmospheric pressure plasma (NEAPP) applied for inactivating fungal spores of P. digitatum is introduced as an environmentally safe and rapid-inactivation 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 O2/Ar plasma. The absolute O density was measured to be 1.4×1014 and 1.5×1015 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 O2/(Ar+O2) 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.

scholarly journals Analysis of Plasma-activated Medium (PAM) in aqueous solution by an Atmospheric Pressure Plasma Jet (APPJ)

2018 ◽  
Vol 197 ◽  
pp. 02013 ◽  
Author(s):  
Andi Wibowo Kinandana ◽  
Sumariyah Sumariyah ◽  
Muhammad Nur
Keyword(s):  
Hydrogen Peroxide ◽  
Species Composition ◽  
Exposure Time ◽  
Atmospheric Pressure ◽  
Atmospheric Pressure Plasma ◽  
Plasma Jet ◽  
Reactive Species ◽  
Atmospheric Pressure Plasma Jet ◽  
Liquid Media ◽  
Pressure Plasma

Plasma-activated medium (PAM) has been produced by exposing a liquid media to Argon plasma jet. The jet plasma exposure to liquid media has produced reactive Oxygen species (ROS) in liquid phase. This study aims to determine the number of reactive species in plasma-activated medium. An atmospheric pressure plasma jet (APPJ) was generated with a dielectric barrier discharge (DBD) column by AC high voltage. Some parameters varied including exposure time; i.e. 5, 10, 15, 20, 25, and 30 min; and the distance between reactor and active media; i.e. 1, 2 and 3 cm. Some analysis conducted including variation of exposure times, the distances of reactor to PAM which affect produced concentration, and the reactive species composition in plasma-activated medium. In addition, temperature characteristics, pH levels, dissolved ozone and dissolved hydrogen peroxide concentrations were also observed in this study. The results showed that increased exposure time resulted in decreased pH, increased temperature and increased concentrations of ozone and hydrogen peroxide. The maximum reactive species composition was obtained at the distance between reactor and plasma-activated medium of 2 cm. Maximum reactive species composition obtained in this study has temperature of 29-30 Celsius degrees; pH 3.5; dissolved ozone 2.97 ppm; and Hydrogen Peroxide 215 ppm.

scholarly journals Cold Atmospheric Pressure Plasma in Wound Healing and Cancer Treatment

2020 ◽  
Vol 10 (19) ◽  
pp. 6898
Author(s):  
Lars Boeckmann ◽  
Mirijam Schäfer ◽  
Thoralf Bernhardt ◽  
Marie Luise Semmler ◽  
Ole Jung ◽  
...  
Keyword(s):  
Wound Healing ◽  
Cancer Therapy ◽  
Cancer Treatment ◽  
Atmospheric Pressure ◽  
Atmospheric Pressure Plasma ◽  
Reactive Species ◽  
Therapeutic Effects ◽  
Preclinical Research ◽  
Pressure Plasma ◽  
Cold Atmospheric Pressure Plasma

Plasma medicine is gaining increasing attention and is moving from basic research into clinical practice. While areas of application are diverse, much research has been conducted assessing the use of cold atmospheric pressure plasma (CAP) in wound healing and cancer treatment—two applications with entirely different goals. In wound healing, a tissue-stimulating effect is intended, whereas cancer therapy aims at killing malignant cells. In this review, we provide an overview of the latest clinical and some preclinical research on the efficacy of CAP in wound healing and cancer therapy. Furthermore, we discuss the current understanding of molecular signaling mechanisms triggered by CAP that grant CAP its antiseptic and tissue regenerating or anti-proliferative and cell death-inducing properties. For the efficacy of CAP in wound healing, already substantial evidence from clinical studies is available, while evidence for therapeutic effects of CAP in oncology is mainly from in vitro and in vivo animal studies. Efforts to elucidate the mode of action of CAP suggest that different components, such as ultraviolet (UV) radiation, electromagnetic fields, and reactive species, may act synergistically, with reactive species being regarded as the major effector by modulating complex and concentration-dependent redox signaling pathways.

Gas Temperature Effect on Reactive Species Generation from the Atmospheric Pressure Air Plasma

2013 ◽  
Vol 10 (8) ◽  
pp. 686-697 ◽  
Author(s):  
Ho Young Kim ◽  
Sung Kil Kang ◽  
Hyoung Cheol Kwon ◽  
Hyun Woo Lee ◽  
Jae Koo Lee
Keyword(s):  
Temperature Effect ◽  
Atmospheric Pressure ◽  
Reactive Species ◽  
Gas Temperature ◽  
Air Plasma

Measurement of the diffusion coefficients of reactive species in dilute gases

1982 ◽  
Vol 380 (1779) ◽  
pp. 241-258 ◽  
Keyword(s):  
Gas Phase ◽  
Diffusion Coefficients ◽  
Atmospheric Pressure ◽  
Room Temperature ◽  
Elevated Temperatures ◽  
Reactive Species ◽  
Resonance Fluorescence ◽  
Hydrogen Atoms ◽  
Chromatographic Effect ◽  
Diffusion Of Hydrogen

A technique has been developed for measuring the diffusion coefficients of atoms and other reactive species in gases below atmospheric pressure. The technique consists of measuring the rate of dispersion of a pulse of reactive species in a stream of gas flowing rapidly ( ca . 10 m s -1 ) down a quartz tube. The reactive species are observed and the profile of the pulses measured by using resonance fluorescence. The technique has been used at room temperature, but in principle measurements could be made at elevated temperatures. Measurements have been made of the rates of diffusion of hydrogen atoms in argon and nitrogen, and values for the diffusion coefficients of 1.61 ± 0.04 and 1.35 ± 0.03 cm 2 s -1 respectively, at 1 atmosphere ( ca . 10 5 Pa) and 294 K, have been obtained. Incidentally to the primary purpose of the experiment, it was observed that the hydrogen atoms spend a small fraction of their time of passage along the tube reversibly adsorbed on its walls. From the measurements, both the partition coefficient, giving the ratio of hydrogen atoms on the walls to those in the gas phase, and the rates of adsorption and desorp­tion can be obtained. This appears to be the first observation of a chromatographic effect for a highly reactive species.

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