Thanks to their portability and the non‐equilibrium character of the discharges, microplasmas are finding application in many scientific disciplines. Although microplasma research has traditionally been application driven, microplasmas represent a new realm in plasma physics that still is not fully understood. This paper reviews existing microplasma sources and discusses charged particle kinetics in various microdischarges. The non‐equilibrium character highlighted in this manuscript raises concerns about the accuracy of fluid models and should trigger further kinetic studies of high‐pressure microdischarges. Finally, an outlook is presented on the biomedical application of microplasmas.

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We demonstrated bacterial ͑Streptococcus mutans͒ inactivation by a radio frequency power driven atmospheric pressure plasma torch with H 2 O 2 entrained in the feedstock gas. Optical emission spectroscopy identified substantial excited state •OH generation inside the plasma and relative •OH formation was verified by optical absorption. The bacterial inactivation rate increased with increasing •OH generation and reached a maximum 5-log 10 reduction with 0.6% H 2 O 2 vapor. Generation of large amounts of toxic ozone is drawback of plasma bacterial inactivation, thus it is significant that the ozone concentration falls within recommended safe allowable levels with addition of H 2 O 2 vapor to the plasma.

BackgroundWe investigate disinfection of a reconstructed human skin model contaminated with biofilm-formative Staphylococcus aureus employing plasma discharge in liquid.Principal FindingsWe observed statistically significant 3.83-log10 (p<0.001) and 1.59-log10 (p<0.05) decreases in colony forming units of adherent S. aureus bacteria and 24 h S. aureus biofilm culture with plasma treatment. Plasma treatment was associated with minimal changes in histological morphology and tissue viability determined by means of MTT assay. Spectral analysis of the plasma discharge indicated the presence of highly reactive atomic oxygen radicals (777 nm and 844 nm) and OH bands in the UV region. The contribution of these and other plasma-generated agents and physical conditions to the reduction in bacterial load are discussed.ConclusionsThese findings demonstrate the potential of liquid plasma treatment as a potential adjunct therapy for chronic wounds.

The properties such as the moment of inertia, the surface redshift and the radius of gyration of rotating neutron stars in the relativistic σ-ω model are studied with the Hartle's method. The relation between the angular velocity of the fluid relative to the local inertial frame and the uniform angular velocity relative to the infinite is calculated.PACS numbers: 04.40. Dg, 95.30.Sf, 97.10.Kc, 97.60.Jd

We demonstrate the application of RF‐excited plasma to remove localized regions of ex vivo tissue. While some limited tissue removal occurs when using discharges in rare gases alone, the addition of chemical precursors results in an enhancement of etch depth and etch profile under essentially identical plasma conditions of delivered power, applied voltage, and gas flow. Specifically, the material removal rate in our experiments using different CH4−xClx additives increased with both (i) the molecular chlorine content (x = 2,3,4) of the selected additive, and (ii) the concentration of haloalkane vapor in the gas stream. We attribute this enhancement to the generation and delivery of chemically reactive radicals from the plasma to the tissue, followed by formation of volatile products (i.e., a chemical, rather than physical or thermal, tissue removal process). In addition we observed that cross‐sectional etch profiles differed with the chosen haloalkane additive chemistries, indicative of corresponding differences in chemistries on profile side‐walls versus bottom walls.

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