Complex partial synchronization patterns in networks of delay-coupled neurons

We study the spatio-temporal dynamics of a multiplex network of delay-coupled FitzHugh-Nagumo oscillators with non-local and fractal connectivities. Apart from chimera states, a new regime of coexistence of slow and fast oscillations is found. An analytical explanation for the emergence of such coexisting partial synchronization patterns is given. Furthermore, we propose a control scheme for the number of fast and slow neurons in each layer. This article is part of the theme issue 'Nonlinear dynamics of delay systems'.

RMS roughness-independent tuning of surface wettability by tailoring silver nanoparticles with a fluorocarbon plasma polymer

A layer of 14 nm-sized Ag nanoparticles undergoes complex transformation when overcoated by thin films of a fluorocarbon plasma polymer. Two regimes of surface evolution are identified, both with invariable RMS roughness. In the early regime, the plasma polymer penetrates between and beneath the nanoparticles, raising them above the substrate and maintaining the multivalued character of the surface roughness. The growth (β) and the dynamic (1/z) exponents are close to zero and the interface bears the features of self-affinity. The presence of inter-particle voids leads to heterogeneous wetting with an apparent water contact angle θ_a = 135°. The multivalued nanotopography results in two possible positions for the water droplet meniscus, yet strong water adhesion indicates that the meniscus is located at the lower part of the spherical nanofeatures. In the late regime, the inter-particle voids become filled and the interface acquires a single valued character. The plasma polymer proceeds to grow on the thus-roughened surface whereas the nanoparticles keep emerging away from the substrate. The RMS roughness remains invariable and lateral correlations propagate with 1/z = 0.27. The surface features multiaffinity which is given by different evolution of length scales associated with the nanoparticles and with the plasma polymer. The wettability turns to the homogeneous wetting state.

In situ coupling of chitosan onto polypropylene foils by an Atmospheric Pressure Air Glow Discharge with a liquid cathode

Atmospheric air plasma treatment of chitosan solutions leads to degradation of chitosan molecules by OH radicals and is accompanied by a predominant cleavage of glycosidic linkages and by a decrease of the molecular weight. The degradation proceeds via first order kinetics with the rate constant of (5.73±0.22)×10(-6)s(-1) and the energetic yield of chitosan bond scission of (2.4±0.2)×10(-8)mol/J. Products of degradation together with intact chitosan molecules adsorb and form coatings on polypropylene foils immersed into the solution that is being plasma treated. The plasma treatment results in strong binding of chitosan to polypropylene due to the formation of covalent bonds between the activated polymer surface and chitosan molecules. Plasma-driven crosslinking is responsible for the accumulation of compressive stress which leads to the development of buckling instabilities in the chitosan coatings.

Taxonomic characterization of new alkaliphilic and alkalitolerant methanotrophs from soda lakes of the Southeastern Transbaikal region and description of Methylomicrobium buryatense sp.nov

Five strains of obligate methanotrophic bacteria (4G, 5G, 6G, 7G and 5B) isolated from bottom sediments of Southeastern Transbaikal soda lakes (pH 9.5-10.5) are taxonomically described. These bacteria are aerobic, Gram-negative monotrichous rods having tightly packed cup-shaped structures on the outer cell wall surface (S-layers) and Type I intracytoplasmic membranes. All the isolates possess particulate methane monooxygenase (pMMO) and one strain (5G) also contains soluble methane monooxygenase (sMMO). They assimilate methane and methanol via the ribulose monophosphate pathway (RuMP). The isolates are alkalitolerant or facultatively alkaliphilic, able to grow at pH 10.5-11.0 and optimally at pH 8.5-9.5. These organisms are obligately dependent on the presence of sodium ions in the growth medium and tolerate up to 0.9-1.4 M NaCl or 1 M NaHCO3. Although being mesophilic, all the isolates are resistant to heating (80 degrees C, 20 min), freezing and drying. Their cellular fatty acids profiles primarily consist of C(16:1). The major phospholipids are phosphatidylethanolamine and phosphatidylglycerol. The main quinone is Q-8. The DNA G+C content ranges from 49.2-51.5 mol %. Comparative 16S rDNA sequencing showed that the newly isolated methanotrophs are related to membres of the Methylomicrobium genus. However, they differ from the known members of this genus by DNA-DNA relatedness. Based on pheno- and genotypic characteristics, we propose a new species of the genus Methylomicrobium Methylomicrobium buryatense sp. nov.

Anoxybacillus pushchinensis gen. nov., sp. nov., a novel anaerobic, alkaliphilic, moderately thermophilic bacterium from manure, and description of Anoxybacillus flavitherms comb. nov

A new strictly anaerobic, alkaliphilic, moderately thermophilic, fermentative, spore-forming bacterium, strain K1T, was isolated from manure samples (pH 6-8). Cells were Gram-positive, straight, non-motile rods that grew at temperatures of 37-66 degrees C (optimum at 62 degrees C) and in a pH range of 8.0-10.5 (optimum at 9.5-9.7). The bacterium fermented D-glucose, sucrose, D-fructose, D-trehalose and starch as carbon and energy sources. It required vitamins and its growth is stimulated by yeast extract. The major metabolic products were H2 and acetate. Cells were catalase-negative and could reduce nitrate to nitrite. The G+C content of the DNA was 42.2 mol%. Based on the phenotypic properties and 16S rDNA sequencing and DNA-DNA hybridization data, strain K1T (= DSM 12423T = ATCC 700785T = VKM B-2193T) was assigned to the new genus Anoxybacillus gen. nov., as a representative of a new species, Anoxybacillus pushchinensis sp. nov. 'Bacillus flavothermus' strain d.y., which was found to be closely related to strain K1T, is described as Anoxybacillus flavithermus comb. nov. (type strain = d.y.T = DSM 2641T).