Template matching algorithms represent a viable tool to locate particles in optical images. A crucial factor of the performance of these methods is the choice of the similarity measure. Recently, it was shown in [Gao and Helgeson, Opt. Express 22 (2014)] that the correlation coefficient (CC) leads to good results. Here, we introduce the mutual information (MI) as a nonlinear similarity measure and compare the performance of the MI and the CC for different noise scenarios. It turns out that the mutual information leads to superior results in the case of signal dependent noise. We propose a novel approach to estimate the velocity of particles which is applicable in imaging scenarios where the particles appear elongated due to their movement. By designing a bank of anisotropic templates supposed to fit the elongation of the particles we are able to reliably estimate their velocity and direction of motion out of a single image.

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 micro particles - 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. (C) 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim

Cold atmospheric plasmas are possible sources of reactive species relevant for biomedical applications. It has been shown that the plasmas can have a disinfection effect mainly due to the produced reactive species. In this abstract, we show the inactivation effect on several microorganisms using Surface Micro-Discharge plasma which is one method to produce cold atmospheric plasmas.

The formation and dissipation of an externally excited planar dust acoustic shock wave in a three-dimensional uniform dust cloud has been observed under microgravity conditions. The experiment has been performed in the dc gas discharge chamber 'Plasma Kristall-4' (Fortov et al 2005 Plasma Phys. Control. Fusion 47 B537) on board the A300 Zero-G airplane. The shock Mach number and compression factor reached 3.5 and 6, correspondingly, with a shock width of about the interparticle distance. Due to the utilization of the polarity-switching dc discharge mode and application of the Rankine–Hugoniot relations, the dust particle electrostatic pressure was determined and the Hugoniot percussive adiabat for the dust subsystem was derived. The obtained data were simulated using thermodynamic properties of highly nonideal Debye–Hückel (Yukawa) systems. Comparison of the experimental and simulated data has demonstrated that the screening length in a dense dusty plasma is not determined by the total ion number density, but rather by those 'effective' ions which are not bounded by negatively charged dust grains. Thus, this work presents a new experimental approach for the investigation of the dense dusty plasma clouds.

Particle pairing in a complex plasma was experimentally studied with the emphasis on pair spatial extent and stability. Micron-size particles were suspended in the (pre)sheath area above the lower electrode in a capacitively coupled radio-frequency discharge in argon. They formed vertical pairs due to the ion wakes created by the flow of ions past particles. We discuss the confinement mechanism for the lower particle, resulting from a combination of the wake field and the field of non-uniform sheath. A model of particle pairs is proposed, which provides good description for the dependence of pair size and stability on experimental parameters.

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.

Objectives: Chronic infected wounds are both socioeconomic and medical problem. Combating bacterial resistance is on of the greatest challenges in the 21st century. In previous reports, 2 min and 5 min cold argon plasma treatments led to a significant reduction in bacterial load in chronic wounds of various causes in patients, regardless of the bacterial species. The observed bactericidal effect of plasma therapy relies on the synergy of reactive oxygen and nitrogen species, charged particles, electric fields, and UVR. This study evaluates the effect of CAPs on wound healing in vivo. Methods: Hard-to-heal chronic wounds of various types in 70 patients (Group A) were treated with cold argon atmospheric plasma for 3-7 minutes. The wound size before and after a course of treatment was compared for plasma-treated and control wounds. Subgroup analyses were performed for all chronic venous ulcers (n=29, Group B) and 5 min plasma treatment of chronic venous ulcers (n=18, Group C). Results: Retrospective analysis of Group A revealed a 10.4 % reduction in width of plasma treated wounds compared to 4.2 % in the control (p=0.270). Length reduced by 8.2 % compared to 5.1% respectively (p=0.068). In Group B a significantly greater reduction in width (17.9 %, p=0.03) was measured in plasma-treated ulcers compared to controls (0 %). However changes in length were not significantly different (9.1 % vs. 8.9 %, p=0.46). The Group C sub analysis showed a highly significant reduction in width (14.6 % vs. 0 %, p=0.008) with plasma treatment but not in ulcer length (2.7 % vs. 8.4 %, p=0.352). Conclusions: This study demonstrates for the first time that plasma treatment can actually accelerate wound healing in a range of chronic wounds, but particularly chronic venous ulcers.

We demonstrate the feasibility to generate surrogates by Fourier-based methods for an incomplete data set. This is performed for the case of a cosmic microwave background analysis, where astrophysical foreground emission, mainly present in the Galactic plane, is a major challenge. The shuffling of the Fourier phases for generating surrogates is now enabled by transforming the spherical harmonics into a new set of basis functions that are orthonormal on the cut sky. The results show that non-Gaussianities and hemispherical asymmetries in the cosmic microwave background as identified in several former investigations, can still be detected even when the complete Galactic plane (vertical bar b vertical bar < 30 degrees) is removed. We conclude that the Galactic plane cannot be the dominant source for these anomalies. The results point towards a violation of statistical isotropy.

The internal structures of most periodic crystalline solids contain defects. This affects various important mechanical and thermal properties of crystals. Since it is very difficult and expensive to track the motion of individual atoms in real solids, macroscopic model systems, such as complex plasmas, are often used. Complex plasmas consist of micrometer-sized grains immersed into an ion-electron plasma. They exist in solidlike, liquidlike, and gaseouslike states and exhibit a range of nonlinear and dynamic effects, most of which have direct analogies in solids and liquids. Slabs of a monolayer hexagonal complex plasma were subjected to a cycle of uniaxial compression and decompression of large amplitudes to achieve plastic deformations, both in experiments and simulations. During the cycle, the internal structure of the lattice exhibited significant rearrangements. Dislocations (point defects) were generated and displaced in the stressed lattice. They tended to glide parallel to their Burgers vectors under load. It was found that the deformation cycle was macroscopically reversible but irreversible at the particle scale.

Plasma jets are currently used in many technological application. In this kind of plasma sources, plasma is delivered by “afterglow”. The main advantage is that the temperature of the afterglow is relatively low, therefore, it is applicable for treating the heat sensitive material. However, the chemistry of the delivered plasma is complicated due to presence of ambient air. For plasma treatment of living tissues in medicine and inanimate surfaces, it is important to have knowledge and control of the chemistry of 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<0.016) reduction in bacterial load in plasma-treated wounds, regardless of the species of bacteria. Analysis of 137 treatments in 10 patients with the MicroPlaSter beta device showed a highly significant reduction (23.5%, P<0.008) in bacterial load. No side-effects occurred and the treatment was well tolerated.CONCLUSIONS:A 2-min treatment with either of two cold atmospheric argon plasma devices is a safe, painless and effective technique to decrease the bacterial load in chronic wounds.

We have investigated the liquid‐like 3D Yukawa system of microparticles confined in a cubic box with the hard walls. The general reconstruction technique (see E. M. Apfelbaum, Phys. Plasmas 14, 123703 (2007)) has been applied to reconstruct the interparticle interaction potential from the obtained pair correlation function at different values of the coupling parameter Γ. It has been shown that for the cases Γ>1 when the pair correlation functions are nonmonotonic, the techniques can not be used to reconstruct the potential, while it is possible to do for the small Γ values (Γ>>1).

Master equations for spherical dust structures are solved numerically using the asymptotic solutions at the center of the structures for the case of absence of external ionization and small diffusions. The structures are determined by a single parameter, the external plasma flux at the surface of the structure. The equilibrium states that are possible in a limited range of this parameter are investigated numerically. It is demonstrated that in the range of existence of equilibria the structures are changing their shapes and type of distributions inside the structures. For large external fluxes the ion and dust distributions can have peaks inside the structures while for low external fluxes the dust distribution has a single maximum at the structure center. The lower is the external flux supporting the structure the larger is its size. An increase of the external flux decreases the accumulation of dust and ions at the center. The total number of dust confined by the structure is larger for larger size structures. Estimates of dust crystallization inside structures are given. The role of diffusion is calculated by perturbations and is shown to be small in all structure regions except the structure edges. In the perturbation theory we use the exact expressions of the diffusion coefficients calculated previously numerically. The regions with dust density peaks inside the structures have been calculated with two order of magnitude larger precision that allows to resolve the structure parameter dependencies inside the peaks. It is shown that although in peaks the gradients of all parameters are increased the diffusion flux is still small and that the continuity and hydrodynamic approach are applicable within an accuracy about several %‐s (© 2011 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)

The recent tremendous progress in understanding physical plasma phenomenon, together with the development of new plasma sources has put growing focus on the application of plasmas in health care. Active plasma components, such as molecules, atoms, ions, electrons and photons, reactive species, ultraviolet radiation, optical and infrared emission and heat have the ability of activating, controlling and catalysing reactions and complex biochemical procedures. Thermal and non-thermal (i.e. cold) plasmas - both already widely established in medicine - are used for various therapeutic applications. Particularly in dermatology, plasma applications hold big potential, for example, in wound healing, such as efficient disinfection or sterilization, therapy of various skin infections or tissue regeneration. This review gives an overview on potential plasma applications in medicine - including the recent research on skin diseases - and summarizes possible interactions between plasmas and living tissue.

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)

Solids are known to have crystal structures, which are often disrupted by defects. The defects can form strings separating crystal grains and disturbing the local number density and orientation of the lattice causing deformations. Using data from complex plasma experiment and molecular dynamics simulation, we have quantified and visualized these deformations. Complex (dusty) plasmas are mixtures of micron-sized spheres with ion-electron plasmas. They can be in solid, liquid, or gaseous states, exhibiting phase transitions, and can be used as model systems to study basic properties of solids at the kinetic level.

A tsunami is a wave with small amplitude offshore that dramatically increases in shallow waters. Here, we present an experimental observation and a molecular dynamics simulation of such amplitude increase of solitons in inhomogeneous crystalline monolayer complex plasma. Complex (dusty) plasmas are mixtures of mesoscopic particles with ion-electron plasmas, which are used to study wave phenomena at the kinetic level with the motion of every particle traced.