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Cold atmospheric argon plasma is recognized as a new contact free approach for the decrease of bacterial load on chronic wounds in patients. So far very limited data are available on its toxicity and mutagenicity on eukaryotic cells. Thus, the toxic/mutagenic potential of cold atmospheric argon plasma using the MicroPlaSter β® , which has been used efficiently in humans treating chronic and acute wounds, was investigated using the XTT assay in keratinocytes and fibroblasts and the HGPRT (hypoxanthine guanine phosphoribosyl transferase) assay with V79 Chinese hamster cells. The tested clinical parameter of a 2 min cold atmospheric argon plasma treatment revealed no relevant toxicity on keratinocytes (viability: 76% ± 0.17%) and on fibroblasts (viability: 81.8 ± 0.10) after 72 hr as compared to the untreated controls. No mutagenicity was detected in the HGPRT assay with V79 cells even after repetitive CAP treatments of 2-10 min every 24 hr for up to 5 days. In contrast, UV-C irradiation of V79 cells, used as a positive control in the HGPRT test, led to DNA damage and mutagenic effects. Our findings indicate that cold atmospheric plasma using the MicroPlaSter β® shows negligible effects on keratinocytes and fibroblasts but no mutagenic potential in the HGPRT assay, indicating a new contact free safe technology. Environ. Mol. Mutagen. 58:172-177, 2017. © 2017 Wiley Periodicals, Inc.

Slow dynamics in an amorphous quasi-two-dimensional complex plasma, comprised of microparticles of two different sizes, was studied experimentally. The motion of individual particles was observed using video microscopy, and the self-part of the intermediate scattering function as well as the mean-squared particle displacement was calculated. The long-time structural relaxation reveals the characteristic behavior near the glass transition. Our results suggest that binary complex plasmas can be an excellent model system to study slow dynamics in classical supercooled fluids.

Complex (dusty) plasmas are composed of weakly ionised gas and charged microparticles and represent the plasma state of soft matter. Due to the ”heavy” component — the microparticles — and the low density of the surrounding medium, the rarefied gas and plasma, it is necessary to perform experiments under microgravity conditions to cover a broad range of experimental parameters which are not available on ground. The investigations have been performed onboard the International Space Station (ISS) with the help of the ”Plasma Crystal-3 Plus” (PK-3 Plus) laboratory. It was perfectly suited for the formation of large stable liquid and crystalline Systems and provided interesting insights into processes like crystallisation and melting, laning in binary mixtures, electrorheological effects due to ac electric fields and projectile interaction with a strongly coupled complex plasma cloud.

Effects of microwave argon non-thermal plasma (NTP) on the facultative intracellular pathogen Listeria monocytogenes were studied. NTP treatment for 2 min caused a 3 log 10 decrease of wild type strain EGDe extracellular bacteria. Similar treatment of infected HEK293 cells caused a 1.5-fold decrease of intracellular EGDe bacteria. The intraphagosomal EGDeΔhly lacked the pore-forming toxin LLO was resistant to NTP. Cell pretreatment with NTP before infection increased EGDe invasion of human HEK293 and murine C26 cells 2.5 and 1.7-fold, respectively. HEK293 cell pretreatment did not affect invasion by EGDe ΔinlA that lacked the invasion factor InlA. Taken together, obtained results demonstrated that a direct NTP effect on intracellular L. monocytogenes was low, still NTP affected interactions between L. monocytogenes and the host cell.

The interplanetary space probe Cassini/Huygens reached Saturn in July 2004 after seven years of cruise phase. The Cosmic Dust Analyzer (CDA) measures the interplanetary, interstellar and planetary dust in our solar system since 1999 and provided unique discoveries. In 1999, CDA detected interstellar dust in the inner solar system followed by the detection of electrical charges of interplanetary dust grains during the cruise phase between Earth and Jupiter. The instrument determined the composition of interplanetary dust and the nanometre sized dust streams originating from Jupiter's moon Io. During the approach to Saturn in 2004, similar streams of submicron grains with speeds in the order of 100 km/s were detected from Saturn's inner and outer ring system and are released to the interplanetary magnetic field. Since 2004 CDA measured more than one million dust impacts characterizing the dust environment of Saturn. The instrument is one of three experiments which discovered the active ice geysers located at the south pole of Saturn's moon Enceladus in 2005. Later, a detailed compositional analysis of the water ice grains in Saturn's E ring system lead to the discovery of large reservoirs of liquid water (oceans) below the icy crust of Enceladus. Finally, the determination of the dust- magnetosphere interaction and the discovery of the extended E ring (at least twice as large as predicted) allowed the definition of a dynamical dust model of Saturn's E ring describing the observed properties. This paper summarizes the discoveries of a ten year story of success based on reliable measurements with the most advanced dust detector flown in space until today. This paper focuses on cruise results and findings achieved at Saturn with a focus on flux and density measurements., 18 pages, 12 Figures, DLRK 2011

Objective Ear, nose and throat infections are among the most common reasons for absence from work. They are usually caused by various bacteria like Haemophilus influenzae, Staphylococcus aureus, Streptococcus pneumoniae and Streptococcus pyogenes. Cold atmospheric plasma (CAP) can effectively eliminate even multi-resistant bacteria and has no cytotoxic or mutagenic effects on the mucosa when applied for less than 60 s. Aim of the study was to evaluate the effects of CAP on common ENT bacteria and on the mucosa of the upper aerodigestive tract. Methods The bactericidal effects of CAP against the bacteria most commonly causing ENT infections were investigated using the colony-forming units assay (CFU) on a Muller-Hinton agar plate after applying CAP for 30, 60, 90 and 120 s. To evaluate the interaction of CAP with mucosal cells, 3D mini organ cultures were treated for up to 180 s, after which cell viability and necrosis induction were evaluated. Results Treatment with CAP for 60 s or longer induced at least a 3-log10 reduction in the bacterial load (> 99.9%). Treatment times shorter than 60 s had only slight cytotoxic effects on cell viability and necrosis whereas treatment times above 60 s showed a fast increase of cytotoxic side effects. Conclusion CAP exhibited strong bactericidal effects on the most common ENT pathogens. Treatment times of up to 60 s showed only minimal adverse reactions in healthy mucosa. CAP could be a promising new therapeutic modality for ENT infections.

Herpes zoster is an acute painful infectious skin condition due to the reactivation of the varicella zoster virus, with increasing incidence in the aging population. Acute pain relief is usually required and post-herpetic neuralgia requiring ongoing analgesia is a well recognised complication. Argon plasma treatment has demonstrated efficacy in reducing bacterial load in chronic wounds, and possibly stimulating wound healing. In this study, weekday 5 min plasma treatments with the MicroPlaSter s device was assessed for safety, pain reduction and healing rates of herpes zoster. 37 inpatients with herpes zoster were treated in a prospective randomized placebo-controlled phase II study with either weekday 5 min of cold atmospheric argon plasma (19, active) or with 5 min of argon gas (18, placebo), in addition to a standard treatment regime. Pain was assessed by visual analogue scale before and after active or placebo application. Digital images of lesions were evaluated independently by three blinded clinicians, with regard to vesicles, erythema and general impression. Analysis revealed a significantly greater (p Weekday 5 min treatments with cold atmospheric argon plasma was safe, painless and effective, improving initial healing and acute pain in herpes zoster lesions.

Using two-dimensional (2D) complex plasmas as an experimental model system, particle-resolved studies of flame propagation in classical 2D solids are carried out. Combining experiments, theory, and molecular dynamics simulations, we demonstrate that the mode-coupling instability operating in 2D complex plasmas reveals all essential features of combustion, such as an activated heat release, two-zone structure of the self-similar temperature profile ("flame front"), as well as thermal expansion of the medium and temperature saturation behind the front. The presented results are of relevance for various fields ranging from combustion and thermochemistry, to chemical physics and synthesis of materials.

The wake-mediated propulsion of an "extra" particle in a channel of two neighboring rows of a two-dimensional plasma crystal, observed experimentally by Du et al. [Phys. Rev. E 89, 021101(R) (2014)], is explained in simulations and theory. We use the simple model of a pointlike ion wake charge to reproduce this intriguing effect in simulations, allowing for a detailed investigation and a deeper understanding of the underlying dynamics. We show that the nonreciprocity of the particle interaction, owing to the wake charges, is responsible for a broken symmetry of the channel that enables a persistent self-propelled motion of the extra particle. We find good agreement of the terminal extra-particle velocity with our theoretical considerations and with experiments., Comment: 7 pages, 4 figures, PRL (https://journals.aps.org/prl/), updated version with correct author affiliations

Microbial control is important to prevent nosocomial infections. Cold atmospheric plasma (CAP) is studied as an alternative disinfectant for dry surfaces. Bacterial endospores including Clostridium difficile and vegetative bacteria including Enterococcus faecium are treated on carriers, considering European testing standards. CAP reduces the spore load (106 cfu) by at least 3 log10 as required, independent from the bioburden (≤10 min treatments). Only a 2 log10 reduction is achieved with vegetative bacteria due to multilayer formation resulting from a higher required load (108 cfu). However, densities

The composition of the gas for the Surface Micro-Discharge (SMD) plasma system is changed by applying variety of binary mixtures with oxygen, nitrogen and argon. Gram-negative Escherichia coli and gram-positive Enterococcus mundtii bacteria strains are inoculated on agar and exposed to the plasma using different gas mixture ratios either with a fixed applied voltage or with a fixed dissipated power. No bacterial reduction is observed in the absence of oxygen. Higher bactericidal efficacy is observed with higher oxygen fraction in the gas composition for the plasma. A threshold of the oxygen fraction is found where the bacterial reduction does not change much. The strong correlation between the bactericidal efficacy and the ozone concentration measured by optical absorption spectroscopy suggests that ozone generated by the SMD plasma is the major agent for the bacterial inactivation under the investigated conditions.

Aim To study the effects exerted by argon microwave nonthermal plasma (NTP) on cell wall-lacking Mollicutes bacteria. Methods and Results 108 CFU ml−1 agar plated Mycoplasma hominis and Acholeplasma laidlawii were treated with the nonthermal microwave argon plasma for 30–300 s. The maximal 10- and 100-fold drop was observed for A. laidlawii and Myc. hominis, respectively. Similarly treated Escherichia coli and Staphylococcus aureus demonstrated the 105 and 103 drop, respectively. Removal of cholesterol affected resistance of A. laidlawii. 10 mmol l−1 antioxidant butylated hydroxytoluene decreased mortality by a factor of 25–200. UV radiation alone caused 25–85% mortality in comparison with the whole NTP. Exogenously added hydrogen peroxide H2O2 did not cause mortality. NTP treatment of Myc. hominis triggered growth of microcolonies, which were several tenfold smaller than a typical colony. Conclusions Despite the lack of cell wall, A. laidlawii and Myc. hominis were more resistant to argon microwave NTP than other tested bacteria. Mycoplasma hominis formed microcolonies upon NTP treatment. A role of UV and active species was demonstrated. Significance and Impact of the Study The first study of NTP effects on Mollicutes revealed importance of a membrane composition for bacterial resistance to NTP. New specific Myc. hominis morphological forms were observed. The study confirmed importance of the concerted action of reactive oxygen species (ROS) with UV and other plasma bioactive agents for NTP bactericidal action.

Two cold atmospheric plasma devices were used (either in an indirect or a direct way) for the treatment of physiologically contaminated forearms in 12 healthy volunteers. After 30 s of plasma treatment, the log reduction of the bacterial load in the plasma treated area was evaluated. It was found that both the indirect and direct plasma application resulted in a highly significant reduction of the bacterial load in the target area. Given the same plasma treatment time, the direct application showed higher mean log reduction in comparison to the indirect one and proved to be significantly more effective.

Previous studies reported a significant reduction in bacterial load in chronic wounds in patients with cold argon plasma. This open retrospective study evaluated effects on wound healing in vivo using the MicroPlaSter alpha device, with wound healing a secondary endpoint. Chronic wounds of various etiologies in 70 patients (Group A) were treated with plasma for 3–7 min. Wound dimensions before and after treatment were compared for plasma-treated and control wounds. Subgroup analyses were performed for all chronic venous ulcers ( n =27, Group B) and 5 min plasma treatment of chronic venous ulcers ( n =18, Group C). Patient acted as own control. In Group A plasma-treated wounds showed a greater reduction in width and length than control wounds. Reduction rates were non-significant. In Group B a significantly greater reduction in width was measured in plasma-treated ulcers compared to controls, but not in ulcer length. Group C showed again a significant reduction in width with plasma treatment but not in ulcer length. This study suggests that wound healing may be accelerated, particularly for chronic venous ulcers.

Aim: Cold atmospheric plasma (CAP) has already proven efficient at disinfection of microorganisms including biofilms. The objective of the present study is to assess the efficacy of CAP against the dermatophytes Trichophyton rubrum and Microsporum canis in vitro. Materials & methods:T. rubrum and M. canis were exposed to CAP for different treatment times and time intervals in vitro. Treatment with ciclopirox olamine or UVC radiation (0.120 J/cm2) served as controls. CAP was generated by the surface microdischarge technology. Fungal colony growth was measured upon CAP treatment. Results: Repeated daily CAP treatments of 10 min demonstrated an inhibition of growth during the treatment period of 9 days. Single CAP treatment sessions for 5, 8 and 10 min, as well as treatments for 5 or 8 min daily, resulted in less fungal growth inhibition. UVC radiation treatment failed, but not ciclopirox olamine. Conclusion: CAP shows promising potential for future application in the treatment of dermatophyte infections.

Cold atmospheric plasma has already been shown to decrease the bacterial load in chronic wounds. However, until now it is not yet known if plasma treatment can also improve wound healing. We aimed to assess the impact of cold atmospheric argon plasma on the process of donor site healing. Forty patients with skin graft donor sites on the upper leg were enrolled in our study. The wound sites were divided into two equally sized areas that were randomly assigned to receive either plasma treatment or placebo (argon gas) for 2 minutes. Donor site healing was evaluated independently by two blinded dermatologists, who compared the wound areas with regard to reepithelialization, blood crusts, fibrin layers, and wound surroundings. From the second treatment day onwards, donor site wound areas treated with plasma (n = 34) showed significantly improved healing compared with placebo-treated areas (day 1, p = 0.25; day 2, p = 0.011; day 3, p < 0.001; day 4, p < 0.001; day 5, p = 0.004; day 6, p = 0.008; day 7, p = 0.031). Positive effects were observed in terms of improved reepithelialization and fewer fibrin layers and blood crusts, whereas wound surroundings were always normal, independent of the type of treatment. Wound infection did not occur in any of the patients, and no relevant side effects were observed. Both types of treatment were well tolerated. The mechanisms contributing to these clinically observed effects should be further investigated.

We report on modifications of the dispersion relation, describing dust density waves in complex plasmas subjected to weak electric fields due to variations of the equilibrium dust densities. The calculations show the essentially different wave dispersion and predict the existence of cutoff wavenumbers, corresponding to aperiodically growing dust density perturbations. The theory explains the preferential range of wavenumbers where the dust density waves can be effectively excited.

Non-thermal plasma technology emerged the medical field in an age of increasing bacterial and fungal resistance and global concerns about hygiene in different health care settings. Thus, the expectations regarding this new promising tool are very high. After teething problems different non-thermal plasma technologies were developed and used in different clinical trials in patients possessing chronic and acute wounds, diverse skin and itching diseases. The results from these trials and the preceding in vitro and ex vivo experiments opened up new fields of applications, which one had not thought of before. More than 5 years of clinical experience so far demonstrated that this plasma technology could be applied in a safe and effective setting to human beings. However, the potential and knowledge is far from being completely exhausted.

Cold atmospheric plasma is an innovative tool in medicine and hygiene. However, there are no regulations or recommendations for experiments to prove the safety of upcoming devices yet. Healthy ex vivo human skin samples were treated with new upcoming plasma devices (FlatPlaSter 2.0 and MiniFlatPlaSter) for safety purposes. The results indicate—besides the safety measurements/calculations of toxic by-products (O3, NO, and NO2) and the UV power density—that a plasma treatment of up to 2 min is tolerable for the skin (histology and electron microscopy experiments) and safe concerning DNA damages (gamma-H2AX stain assay).

In the past few years, cold atmospheric plasma (CAP) has evolved into a new tool in the fight against nosocomial infections and antibiotic-resistant microorganisms. The products generated by the plasma-electrons, ions, reactive species and UV light-represent a 'lethal cocktail' for different kinds of pathogen, which opens up possible applications in hygiene and medicine. Nevertheless, to ensure the safe usage of CAP on skin (e.g., to treat wounds or skin diseases) several pre-clinical in vitro studies have to be performed before implementing clinical trials on humans. In the study presented here, inactivation experiments with Escherichia coli were carried out to identify the necessary plasma dosage for a 5 log reduction: with a small hand-held battery-operated CAP device, these disinfection properties were achieved after application during 30s. This and higher plasma dosages were then used to analyze the mutagenicity induced in V79 Chinese hamster cells-to furthermore define a 'safe application window'-with the HPRT (hypoxanthine-guanine phosphoribosyl transferase) mutation assay. The results show that a CAP treatment of up to 240 s and repeated treatments of 30s every 12h did not induce mutagenicity at the Hprt locus beyond naturally occurring spontaneous mutations.

Over the past few years, the application of cold atmospheric plasma (CAP) in medicine has developed into an innovative field of research of rapidly growing importance. One promising new medical application of CAP is cancer treatment. Different studies revealed that CAP may potentially affect the cell cycle and cause cell apoptosis or necrosis in tumor cells dependent on the CAP device and doses. In this study, we used a novel hand-held and battery-operated CAP device utilizing the surface micro discharge (SMD) technology for plasma production in air and consequently analysed dose-dependent CAP treatment effects on melanoma cells. After 2 min of CAP treatment, we observed irreversible cell inactivation. Phospho-H2AX immunofluorescence staining and Flow cytometric analysis demonstrated that 2 min of CAP treatment induces DNA damage, promotes induction of Sub-G1 phase and strongly increases apoptosis. Further, protein array technology revealed induction of pro-apoptotic events like p53 and Rad17 phosphorylation of Cytochrome c release and activation of Caspase-3. Interestingly, using lower CAP doses with 1 min of treatment, almost no apoptosis was observed but long-term inhibition of proliferation. H3K9 immunofluorescence, SA-ß-Gal staining and p21 expression revealed that especially these low CAP doses induce senescence in melanoma cells. In summary, we observed differences in induction of apoptosis or senescence of tumor cells in respond to different CAP doses using a new CAP device. The mechanism of senescence with regard to plasma therapy was so far not described previously and is of great importance for therapeutic application of CAP.

New complex-plasma facility, Plasmakristall-4 (PK-4), has been recently commissioned on board the International Space Station. In complex plasmas, the subsystem of μm-sized microparticles immersed in low-pressure weakly ionized gas-discharge plasmas becomes strongly coupled due to the high (103–104 e) electric charge on the microparticle surface. The microparticle subsystem of complex plasmas is available for the observation at the kinetic level, which makes complex plasmas appropriate for particle-resolved modeling of classical condensed matter phenomena. The main purpose of PK-4 is the investigation of flowing complex plasmas. To generate plasma, PK-4 makes use of a classical dc discharge in a glass tube, whose polarity can be switched with the frequency of the order of 100 Hz. This frequency is high enough not to be felt by the relatively heavy microparticles. The duty cycle of the polarity switching can be also varied allowing to vary the drift velocity of the microparticles and (when necessary) to trap them. The facility is equipped with two videocameras and illumination laser for the microparticle imaging, kaleidoscopic plasma glow observation system and minispectrometer for plasma diagnostics and various microparticle manipulation devices (e.g., powerful manipulation laser). Scientific experiments are programmed in the form of scripts written with the help of specially developed C scripting language libraries. PK-4 is mainly operated from the ground (control center CADMOS in Toulouse, France) with the support of the space station crew. Data recorded during the experiments are later on delivered to the ground on the removable hard disk drives and distributed to participating scientists for the detailed analysis.

We address an experimental observation of pattern formation in a magnetised rf plasma. The experiments are carried out in a electrically grounded aluminium chamber which is housed inside a rotatable superconducting magnetic coil. The plasma is formed by applying a rf voltage in parallel plate electrodes in push-pull mode under the background of argon gas. The time evolution of plasma intensity shows that a homogeneous plasma breaks into several concentric radial spatiotemoral bright and dark rings. These rings propagate radially at considerably low pressure and a constant magnetic field. These patterns are observed to trap small dust particles/grains in their potential. Exploiting this property of the patterns, a novel technique to measure the electric field associated with the patterns is described. The resulting estimates of the corresponding field intensity are presented. At other specific discharge parameters the plasma shows a range of special type of characteristic structures observed in certain other chemical, mechanical and biological systems., It contains four pages with four figures

This paper presents experimental results on the control of periodic contraction of the void border and proposes a hypothesis on its mechanism, based on the distinctive features of a dusty plasma - its heterogeneity and the presence of the volumetric sink in it.

The spectral asymmetry of the wave energy distribution of dust particles during mode-coupling induced melting, observed for the first time in plasma crystals by Cou\"edel et al. [Phys. Rev. E 89, 053108 (2014)], is studied theoretically and by molecular-dynamics simulations. It is shown that an anisotropy of the well confining the microparticles selects the directions of preferred particle motion. The observed differences in intensity of waves of opposed directions is explained by a nonvanishing phonon flux. Anisotropic phonon scattering by defects and Umklapp scattering are proposed as possible reasons for the mean phonon flux., Comment: 12 pages, 8 figures, Phys. Rev. E (http://journals.aps.org/pre), accepted

We report the modifications of compressional Mach cone propagation characteristics due to \textcolor{black}{the} polarization force acting on micron size dust particles embedded in a non-uniform plasma. We solve the hydrodynamic fluid equations for highly charged dust particles to investigate the Mach cone by incorporating the polarization force in the momentum equation and observe the structural change on lateral wakes at different polarization force for a given Mach number and Epstein drag force. We also notice that the maximum amplitude of normalized dust density perturbation decreases with the increase of polarization interaction when the other parameters remain constant., Comment: 7 pages with 4 figures

Non-thermal plasma (NTP) consists of a huge amount of biologically active particles, whereas its tem- perature is close to ambient. This combination allows one to use NTP as a perspective tool for solving different biomedical tasks, including antitumor therapy. The treatment of tumor cells with NTP caused dose-dependent effects, such as growth arrest and apoptosis. However, while the outcome of NTP treatment has been established, the molecular mechanisms of the interaction between NTP and eukaryotic cells have not been thoroughly stud- ied thus far. In this work, the mechanisms and the type of death of human colon carcinoma HCT 116 cells upon application of non-thermal argon plasma were studied. The effect of NTP on the major stress-activated protein p53 was investigated. The results demonstrate that the viability of HCT116 cells upon plasma treatment is de- pendent on the functional p53 protein. NTP treatment caused an increase in the intracellular concentration of p53 and the induction of the p53-controlled regulon. The p53-dependent accumulation of active proapoptotic caspase-3 was shown in NTP-treated cells. The study was the first to demonstrate that treatment of human colon carcinoma cells with NTP results in p53-dependent apoptosis. The results obtained contribute to our under- standing of the applicability of NTP in antitumor therapy. KEYWORDS non-thermal plasma; protein p53; apoptosis. ABBREVIATIONS NTP - non-thermal plasma.

In this study we investigated the sensitivity of Deinococcus radiodurans to contact-free cold atmospheric plasma treatment as part of a project to establish new efficient procedures for disinfection of inanimate surfaces. The Gram-positive D. radiodurans is one of the most resistant microorganisms worldwide. Stationary phases of D. radiodurans were exposed to cold atmospheric plasma for different time intervals or to ultraviolet C (UVC) radiation at dose rates of 0.001–0.0656 J cm−2, respectively. A methicillin-resistant Staphylococcus aureus strain (MRSA) served as control for Gram-positive bacteria. The surface microdischarge plasma technology was used for generation of cold atmospheric plasma. A plasma discharge was ignited using ambient air. Surprisingly, D. radiodurans was sensitive to the cold atmospheric plasma treatment in the same range as the MRSA strain. Survival of both bacteria decreased with increasing plasma exposure times up to 6 log10 cycles (>99.999 %) within 20 s of plasma treatment. In contrast, UVC radiation of both bacteria demonstrated that D. radiodurans was more resistant to UVC treatment than MRSA. Cold atmospheric plasma seems to be a promising tool for industrial and clinical purposes where time-saving is a critical point to achieve efficient disinfection of inanimate surfaces and where protection from corrosive materials is needed.

This paper tries to focus on pertinent issues in health care and analyses how cold atmospheric plasmas can contribute towards the long-standing problems identified. It starts quite generally by looking at the major elements that make up our current health care system, the aims that govern these and the corresponding requirements on health care products. It then proceeds to identify areas where current research promises contributions from the new cold plasma technologies. It turns out that there are indeed many areas where investments in plasma health care could pay off, both in terms of cost and in reduction of human suffering (© 2012 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim)

Physical cold atmospheric surface microdischarge (SMD) plasma operating in ambient air has promising properties for the sterilization of sensitive medical devices where conventional methods are not applicable. Furthermore, SMD plasma could revolutionize the field of disinfection at health care facilities. The antimicrobial effects on Gram-negative and Gram-positive bacteria of clinical relevance, as well as the fungus Candida albicans , were tested. Thirty seconds of plasma treatment led to a 4 to 6 log 10 CFU reduction on agar plates. C. albicans was the hardest to inactivate. The sterilizing effect on standard bioindicators (bacterial endospores) was evaluated on dry test specimens that were wrapped in Tyvek coupons. The experimental D 23 ° C values for Bacillus subtilis , Bacillus pumilus , Bacillus atrophaeus , and Geobacillus stearothermophilus were determined as 0.3 min, 0.5 min, 0.6 min, and 0.9 min, respectively. These decimal reduction times ( D values) are distinctly lower than D values obtained with other reference methods. Importantly, the high inactivation rate was independent of the material of the test specimen. Possible inactivation mechanisms for relevant microorganisms are briefly discussed, emphasizing the important role of neutral reactive plasma species and pointing to recent diagnostic methods that will contribute to a better understanding of the strong biocidal effect of SMD air plasma.

Background The development of antibiotic resistance by microorganisms is an increasing problem in medicine. In chronic wounds, bacterial colonization is associated with impaired healing. Cold atmospheric plasma is an innovative promising tool to deal with these problems. Objectives The 5-min argon plasma treatment has already demonstrated efficacy in reducing bacterial numbers in chronic infected wounds in vivo. In this study we investigated a 2-min plasma treatment with the same device and the next-generation device, to assess safety and reduction in bacterial load, regardless of the kind of bacteria and their resistance level in chronic wounds. Methods Twenty-four patients with chronic infected wounds were treated in a prospective randomized controlled phase II study with 2 min of cold atmospheric argon plasma every day: 14 with MicroPlaSter alpha device, 10 with MicroPlaSter beta device (next-generation device) in addition to standard wound care. The patient acted as his ⁄her own control. Bacterial species were detected by standard bacterial swabs and bacterial load by semiquantitative count on nitrocellulose filters. The plasma settings were the same as in the previous phase II study in which wounds were exposed for 5 min to argon plasma. Results Analysis of 70 treatments in 14 patients with the MicroPlaSter alpha device revealed a significant (40%, P

Candida albicans is one of the main species able to form a biofilm on almost any surface, causing both skin and superficial mucosal infections. The worldwide increase in antifungal resistance has led to a decrease in the efficacy of standard therapies, prolonging treatment time and increasing health care costs. Therefore, the aim of this work was to demonstrate the applicability of atmospheric plasma at room temperature for inactivating C. albicans growing in biofilms without thermally damaging heat-sensitive materials. This so-called cold atmospheric plasma is produced by applying high voltage to accelerate electrons, which ionize the surrounding air, leading to the production of charged particles, reactive species, and photons. A newly developed plasma device was used, which exhibits a large plasma-generating surface area of 9 by 13 cm (117 cm 2 ). Different time points were selected to achieve an optimum inactivation efficacy range of ≥3 log 10 to 5 log 10 reduction in CFU per milliliter, and the results were compared with those of 70% ethanol. The results obtained show that contact-free antifungal inactivation of Candida biofilms by cold atmospheric plasma is a promising tool for disinfection of surfaces (and items) in both health care settings and the food industry, where ethanol disinfection should be avoided.

Non-thermal plasma (NTP) is a flow of partially ionized argon gas at an ambient macroscopic temperature and is microbicidal for bacteria, viruses and fungi. Viability of the Gram-negative obligate intracellular bacterial parasite Chlamydia trachomatis and its host cells was investigated after NTP treatment. NTP treatment of C. trachomatis extracellular elementary bodies (EBs) diminished the concentration of infectious bacteria by a factor of 9×10(4), as established by the parallel infection of murine fibroblast McCoy cells with treated and control EBs. NTP treatment of infected McCoy cells caused disruption of membrane-restricted vacuoles (inclusions), where C. trachomatis intracellular reticulate bodies (RBs) multiply, and a 2×10(6)-fold reduction in the concentration of infectious bacteria. When the samples were covered with magnesium fluoride glass to obstruct plasma particles and UV rays alone were applied, the bactericidal effect was reduced 1.4×10(1)-fold and 5×10(4)-fold for EBs and RBs, respectively. NTP treatment caused the viability of host McCoy cells to diminish by 19%. Therefore, the results obtained demonstrated that (i) both extracellular and intracellular forms of C. trachomatis are sensitive to NTP treatment; (ii) the reduction in concentration of infectious bacteria after NTP treatment of infected cells is superior to the reduction in viability of host cells; and (iii) the effect of NTP on intracellular bacteria does not depend on UV rays.

Cold atmospheric plasma (CAP) is a novel tool for various applications ranging from hygiene and cosmetics to medicine. In recent years, various CAP devices have been developed for medical applicati...

Complex plasmas are low-temperature plasmas containing micron-sized particles (microparticles) such as dust grains. These are present in astrophysical systems (comets, molecular clouds, et al.) and in technological applications (microchip production by plasma etching, deposition of solar cells, et al.). Complex plasmas are also of interest in basic science because these are often used as models for many other strongly coupled many-body systems in solid state, fluid, or plasma physics. Since gravity has a strong influence on the microparticle component, experiments under microgravity (parabolic flights, sounding rockets, International Space Station (ISS)) are performed. Interaction between microparticles depends on plasma parameters such as ion density or ion temperature. Also, the presence of microparticles may change the properties of background plasma. Therefore, the background plasma needs to be characterized to provide adequate interpretation of the microgravity experiments. For this purpose a dedicated high-speed diagnostic system has been set up.

Confocal Raman spectroscopy is a noninvasive alternative to established cell imaging methods because it does not require chemical fixation, the use of fluorescent markers, or genetic engineering. In particular, single live-cell, high-resolution imaging by confocal Raman microscopy is desirable because it allows further experiments concerning the individually investigated cells. However, to derive meaningful images from the spectroscopic data, one must identify cell components within the dataset. Using immunofluorescence images as a reference, we derive Raman spectral signatures by means of information measures to identify cell components such as the nucleus, the endoplasmic reticulum, the Golgi apparatus, and mitochondria. The extracted signatures allow us to generate representations equivalent to conventional (immuno)fluorescence images with more than three cell components at a time, exploiting the Raman spectral information alone.

Background To look into new potential indications for physical plasma and because some reports suggest plasma having antipruritic effects, we investigated the treatment of pruritus that often represents a therapeutic challenge. Objectives To assess the efficacy and safety of cold atmospheric argon plasma as add-on-therapy in pruritic diseases. Methods We treated 46 patients with various pruritic diseases with cold plasma for 2 min daily in addition to standard treatment. All patients served as their own control, when their pruritic disease was treated with argon gas (placebo). The outcome measure was a long-term and short-term reduction in itching measured by means of a visual analogue score (VAS). Results The VAS scores at baseline were comparable (plasma 4.57, SD 2.38, argon 4.34, SD 2.35). We did not find any significant differences in VAS reduction between plasma and argon: long-term VAS difference of 1.97 (SD 1.33) for plasma and 1.74 (SD 2.37) for argon [P = 0.224, 95% CI: (−0.15; 0.60)], short-term VAS difference of 1.92 (SD 1.33) for plasma and 1.97 (SD 1.29) for argon [P = 0.544, 95% CI: (−0.21; 0.11)]. In both groups, patients experienced a significant reduction of pruritus at the end of therapy compared to baseline [plasma 1.97 (P

A new design evolved from the surface microdischarge electrode system has been developed for the application of surface disinfection. Having the electrode encapsulated in a dielectric surface the plasma is produced directly on the surface of the electrode which therefore becomes disinfected. Experiments with bacteria were carried out and results show that the surface can be disinfected within 30s with typical operating conditions. Even sterilization appears possible in a reasonable time. Possible applications of this electrode design are discussed for regular disinfection of work surfaces, laboratory benches, etc.

The formation of strongly nonideal Coulomb systems of a large number (∼104) of charged diamagnetic macroparticles in a cusp magnetic trap under microgravity conditions has been experimentally studied. The experiments have performed in the Russian segment of the International Space Station in the framework of the Coulomb Crystal experiment. Using the data of the videorecording of the positions of the particles in the magnetic trap, the magnetic susceptibility and charge of the particles have been estimated and the period of the oscillations of the cloud of the particles, as well as the damping rate of oscillations, has been determined.

We present a model-independent investigation of the WMAP data with respect to scale- dependent non-Gaussianities (NGs) by employing the method of constrained randomization. For generating so-called surrogate maps a shuffling scheme is applied to the Fourier phases of the original data, which allows to test for the presence of higher order correlations (HOCs) on well-defined scales. Using scaling indices as test statistics we find highly significant signatures for non-Gaussianities when considering all scales. We test for NGs in the bands l = [2,20], l = [20,60], l = [60,120] and l = [120,300]. We find highly significant signatures for non-Gaussianities and ecliptic hemispherical asymmetries for l = [2, 20]. We also obtain highly significant deviations from Gaussianity for the band l = [120,300]. The result for the full l-range can be interpreted as a superposition of the signatures found in the bands l = [2, 20] and l = [120, 300]. We find remarkably similar results when analyzing different ILC-like maps. We perform a set of tests to investigate if the detected anomalies can be explained by systematics. While no test can convincingly rule out the intrinsic nature of the anomalies for the low l case, the ILC map making procedure and/or residual noise in the maps can also lead to NGs at small scales. Our investigations prove that there are phase correlations in the WMAP data of the CMB. In the absence of an explanation in terms of Galactic foregrounds or known systematic artefacts, the signatures at low l must so far be taken to be cosmological at high significance. These findings strongly disagree with predictions of isotropic cosmologies with single field slow roll inflation. The task is now to elucidate the origin of the phase correlations and to understand the physical processes leading to these scale-dependent non-Gaussianities - if systematics as cause for them must be ruled out.

Strongly coupled magnetorheological (MR) systems differ from regular simple or complex fluids since the effective interparticle interaction is controlled by external fields and thus provides a tunable anisotropic contribution. This, in turn, causes remarkable diversified phase diagrams of MR-systems. Our analysis of fluid–fluid transitions is based on a modified Ornstein–Zernike (OZ) equation which allows us to calculate structural properties of magnetorheological fluids with anisotropic (dipolar) interactions. The results are compared with MC simulations.

The shapes of dust self-organized structures in presence of volume ionization is investigated. Master Equations for small diffusions and presence of an external ionization describing spherical dust structures are solved numerically using asymptotic solutions at the center of the structures. The structures are determined by two parameters, the external plasma flux at the surface of the structures and the power of volume ionizations. It is shown that the range of possible equilibrium states is reduced with an increase of the ionization power. This reduction is due mainly to an increase of the minimum possible value of ion density at the center of the structure for which the equilibrium is possible (an increase of minimum possible external flux). It is found that for certain large ionization power the equilibrium structure without void at the center cannot exist. The critical value of ionization power is found numerically. In the range of ionization power where the equilibria is possible the distribution of the parameters inside the structures are investigated by solving the Master Equations in the limits of small and large ionization power (© 2011 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim)

Self-organized dust structures are investigated using a Gurevich-Parker model for non-linear dust screening. The non-linear dust drag coefficients and non-linear diffusion coefficients are calculated numerically as functions of nonlinear parameter for screening, dust density and ion flux drift velocity. Nonlinear ion dust drag inside the structures creates an electric field with potential well for ions at the structure center. The equilibrium dust structures confine both the dust grains and the plasma particles, have a finite size and have inside an enhanced dust and ion densities. The necessary conditions for existence of equilibrium dust structures are found. The equilibrium dust structures are determined by two global parameters related to the external plasma flux and to the power of ionization. The equilibrium exist only in a restricted phase space of these two parameters and depends on the the drag coefficient at the structure center. The equilibrium requirements are found using non-linear drag coefficient calculated numerically. It is shown that this phase space area can be broad but it is systematically decreasing with an increase of the ionization rate. It is found that equilibrium exists for dust structures with large dust and ion density concentration at the center and that for these structures the ion diffusion is strongly suppressed by ion scattering on non-linearly screened grains. The results of the theory can be used to interpret the recently observed compact dust structures in micro-gravity experiments and can provide some recommendations for future micro-gravity experiments in spherical chambers (© 2011 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim)