This introductory review on plasma health care is intended to provide the interested reader with a summary of the current status of this emerging field, its scope, and its broad interdisciplinary approach, ranging from plasma physics, chemistry and technology, to microbiology, biochemistry, biophysics, medicine and hygiene. Apart from the basic plasma processes and the restrictions and requirements set by international health standards, the review focuses on plasma interaction with prokaryotic cells (bacteria), eukaryotic cells (mammalian cells), cell membranes, DNA etc. In so doing, some of the unfamiliar terminology—an unavoidable by-product of interdisciplinary research—is covered and explained. Plasma health care may provide a fast and efficient new path for effective hospital (and other public buildings) hygiene— helping to prevent and contain diseases that are continuously gaining ground as resistance of pathogens to antibiotics grows. The delivery of medically active 'substances' at the molecular or ionic level is another exciting topic of research through effects on cell walls (permeabilization), cell excitation (paracrine action) and the introduction of reactive species into cell cytoplasm. Electric fields, charging of surfaces, current flows etc can also affect tissue in a controlled way. The field is young and hopes are high. It is fitting to cover the beginnings in New Journal of Physics, since it is the physics (and non- equilibrium chemistry) of room temperature atmospheric pressure plasmas that have made this development of plasma health care possible.

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Plasma medicine: an introductory review

Reactive species in non-equilibrium atmospheric-pressure plasmas: Generation, transport, and biological effects

article i nfo The Lhasa Terrane in southern Tibet has long been accepted as the last geological block accreted to Eurasia before its collision with the northward drifting Indian continent in the Cenozoic, but its lithospheric architecture, drift and growth histories and the nature of its northern suture with Eurasia via the Qiangtang Terrane remain enigmatic. Using zircon in situ U-Pb and Lu-Hf isotopic and bulk-rock geochemical data of Mesozoic-Early Tertiary magmatic rocks sampled along four north-south traverses across the Lhasa Terrane, we show that the Lhasa Terrane has ancient basement rocks of Proterozoic and Archean ages (up to 2870 Ma) in its centre with younger and juvenile crust (Phanerozoic) accreted towards its both northern and southern edges. This finding proves that the central Lhasa subterrane was once a microcontinent. This continent has survived from its long journey across the Paleo-Tethyan Ocean basins and has grown at the edges through magmatism resulting from oceanic lithosphere subduction towards beneath it during its journey and subsequent collisions with the Qiangtang Terrane to the north and with the Indian continent to the south. Zircon Hf isotope data indicate significant mantle source contributions to the generation of these granitoid rocks (e.g., ~50-90%, 0-70%, and 30-100% to the Mesozoic magmatism in the southern, central, and northern Lhasa subterranes, respectively). We suggest that much of the Mesozoic magmatism in the Lhasa Terrane may be associated with the southward Bangong-Nujiang Tethyan seafloor subduction beneath the Lhasa Terrane, which likely began in the Middle Permian (or earlier) and ceased in the late Early Cretaceous, and that the significant changes of zircon eHf(t) at ~113 and ~52 Ma record tectonomagmatic activities as a result of slab break-off and related mantle melting events following the Qiangtang-Lhasa amalgamation and India-Lhasa amalgamation, respectively. These results manifest the efficacy of zircons as a chronometer (U-Pb dating) and a geochemical tracer (Hf isotopes) in understanding the origin and histories of lithospheric plates and in revealing the tectonic evolution of old orogenies in the context of plate tectonics.

The Lhasa Terrane: Record of a microcontinent and its histories of drift and growth

Plasmas for medicine

Atmospheric-pressure non-equilibrium plasma jets (APNP-Js), which generate plasma in open space rather than in a confined discharge gap, have recently been a topic of great interest. In this paper, the development of APNP-Js will be reviewed. Firstly, the APNP-Js are grouped based on the type of gas used to ignite them and their characteristics are discussed in detail. Secondly, one of the most interesting phenomena of APNP-Js, the ?plasma bullet?, is discussed and its behavior described. Thirdly, the very recent developments on the behavior of plasma jets when launched in a controlled environment and pressure are also introduced. This is followed by a discussion on the interaction between plasma jets. Finally, perspectives on APNP-J research are presented.

https://iopscience.iop.org/article/10.1088/0963-0252/21/3/034005/pdf

On atmospheric-pressure non-equilibrium plasma jets and plasma bullets

A single electrode room-temperature atmospheric pressure plasma plume generated between a high-voltage electrode and the surrounding room air is reported. The plasma plume has a peak current of about 360mA. This is highest current carried by a room-temperature plasma plume ever reported. The rotational and vibrational temperature of the plasma plume is about 300 and 2950K, respectively. Emission spectra show that excited species, such as O, OH, N2+, etc., are present in the plasma plume.

A single electrode room-temperature plasma jet device for biomedical applications

The roles of various plasma agents in the inactivation of bacteria have recently been investigated. However, up to now, the effect of the charged particles on the inactivation of bacteria is not well understood. In this paper, an atmospheric pressure plasma jet device, which generates a cold plasma plume carrying a peak current of 300 mA, is used to investigate the role of the charged particles in the inactivation process. It is found that the charged particles play a minor role in the inactivation process when He/N2(3%) is used as working gas. On the other hand, when He/O2(3%) is used, the charged particles are expected to play an important role in the inactivation of bacteria. Further analysis shows that the negative ions O2− might be the charged particles that are playing the role. Besides, it is found that the active species, including O, O3, and metastable state O2∗, can play a crucial role in the inactivation of the bacteria. However, the excited He∗, N2 C Π3u, and N2+ B Σ2u+ have no significant direct effect on the inactivation of bacteria. It is also concluded that heat and UV play no or minor role in the inactivation process.

The roles of the various plasma agents in the inactivation of bacteria

In this letter, a room temperature atmospheric pressure plasma jet device is reported. The high voltage electrode of the device is covered by a quartz tube with one end closed. The device, which is driven by a kilohertz ac power supply, is capable of generating a plasma plume up to 11cm long in the surrounding room air. The rotational and vibrational temperatures of the plasma plume are 300 and 2300K, respectively. A simple electrical model shows that, when the plasma plume is contacted with a human, the voltage drop on the human is less than 66V for applied voltage of 5kV (rms).

An 11 cm long atmospheric pressure cold plasma plume for applications of plasma medicine

The application of cold plasma in sterilization of a root canal of a tooth has recently attracted great attention. In this paper, a reliable and user-friendly plasma-jet device, which can generate plasma inside the root canal, is reported. The plasma can be touched by bare hands and can be directed manually by a user to place it into root canal for disinfection without causing any painful sensation. When He/O2(20%) is used as working gas, the rotational and vibrational temperatures of the plasma are about 300 K and 2700 K, respectively. The peak discharge current is about 10 mA. Preliminary inactivation experiment results show that it can efficiently kill enterococcus faecalis , one of the main types of bacterium causing failure of root-canal treatment in several minutes.

An $RC$ Plasma Device for Sterilization of Root Canal of Teeth

Zircon U-Pb age and Hf isotope, and major and trace element compositions were reported for granite at Quanyishang, which intruded into the Kongling complex in Yichang, Hubei Province The results show that the Quanyishang granite is rich in silicon and alkalis but poor in calcium and magnesium, and displays enrichment in Ga, Y, Zr, Nb but depletion in Sr and Ba, exhibiting the post-orogenic A-type affinity 90% zircons from the granite are concordant, and give a middle Paleoproterozoic magmatic crystallization age (mean 1854 Ma) Initial Hf isotope ratios (176Hf/177Hf)i of the middle Paleoproterozoic zircons range from 0280863 to 0281134 and they have negative eHf(t) values with a minimum of −263 These zircons give the depleted mantle model ages (TDM) of 29–33 Ga (mean 30 Ga), and the average crustal model ages (Tcrust) of 36–42 Ga (mean 38 Ga) A Mesoarchean grain with 207Pb/206Pb age of 2859 Ma has a slightly high TDM (34 Ga) but similar Tcrust (38 Ga) to the Paleoproterozoic zircons All these data suggest that the source materials of the Quanyishang A-type granite are unusually old, at least ⩾29 Ga (even Eoarchean) The event of crustal remelting, which resulted in the formation of the Quanyishang granite in the middle Paleoproterozoic, recorded the cratonization of the Yangtze continent The process may have relation to the extension and collapse of the deep crust with Archean ages, in response to the transition stage of the assembly and breakup of the Columbia supercontinent

Qing Xiong

Papers

A single electrode room-temperature plasma jet device for biomedical applications

The roles of the various plasma agents in the inactivation of bacteria

An 11 cm long atmospheric pressure cold plasma plume for applications of plasma medicine

An $RC$ Plasma Device for Sterilization of Root Canal of Teeth

Zircon U-Pb age and Hf isotope of Quanyishang A-type granite in Yichang: signification for the Yangtze continental cratonization in Paleoproterozoic