Measurement of the Pion Form Factor with CMD-3 Detector and Its Implication to the Hadronic Contribution to Muon (g-2).

The cross section of the process e^{+}e^{-}→π^{+}π^{-} has been measured in the center-of-mass energy range from 0.32 to 1.2 GeV with the CMD-3 detector at the electron-positron collider VEPP-2000. The measurement is based on an integrated luminosity of about 88 pb^{-1}, of which 62 pb^{-1} represent a complete dataset collected by CMD-3 at center-of-mass energies below 1 GeV. In the dominant region near the ρ resonance a systematic uncertainty of 0.7% was achieved. The implications of the presented results for the evaluation of the hadronic contribution to the anomalous magnetic moment of the muon are discussed.

Machine Learning Non-Markovian Quantum Dynamics.

Machine learning methods have proved to be useful for the recognition of patterns in statistical data. The measurement outcomes are intrinsically random in quantum physics, however, they do have a pattern when the measurements are performed successively on an open quantum system. This pattern is due to the system-environment interaction and contains information about the relaxation rates as well as non-Markovian memory effects. Here we develop a method to extract the information about the unknown environment from a series of projective single-shot measurements on the system (without resorting to the process tomography). The method is based on embedding the non-Markovian system dynamics into a Markovian dynamics of the system and the effective reservoir of finite dimension. The generator of Markovian embedding is learned by the maximum likelihood estimation. We verify the method by comparing its prediction with an exactly solvable non-Markovian dynamics. The developed algorithm to learn unknown quantum environments enables one to efficiently control and manipulate quantum systems.

Transition from spherical to irregular dispersed phase in water/oil emulsions.

Bulk properties of transparent and dilute water in paraffin oil emulsions stabilized with sodium dodecyl sulfate (SDS) are analyzed by optical scanning tomography. Each scanning shot of the considered emulsions has a precision of 1 µm. The influence of aluminum oxide nanoparticles in the structure of the water droplets is investigated. Depending on concentrations of SDS and nanoparticles, a transition occurs in their shape that changes from spherical to polymorphous. This transition is controlled by the SDS/alumina nanoparticles mixing ratio and is described using an identification procedure of the topology of the gray level contours extracted from each images. The transition occurs for a critical mixing ratio of Rcrit ≈ 0.05 which does not significantly depend on temperature and electrolyte concentration. This structural change seems to be a general feature when emulsifying dispersions and most probably involves both interfacial and bulk phenomena.

Characterization of micro- and nanocapsules for self-healing anti-corrosion coatings by high-resolution SEM with coupled transmission mode and EDX.

The observation of morphological details down to the nanometer range of the outer surface of micro-, submicro- and nanoparticles in a high-resolution scanning electron microscope (SEM) was extended with in-depth observation by enabling the transmission mode in the SEM, i.e. TSEM. The micro- and nanocapsules characterized in this study were fabricated as depots for protective agents to be embedded in innovative self-healing coatings. By combining the two imaging modes (upper and in-depth observation) complementing each other a better characterisation by a more comprehensive interpretation of the "consistency" of the challenging specimens, e.g. including details "hidden" beyond the surface or the real specimen shape at all, has been attained. Furthermore, the preparation of the quasi electron transparent samples onto thin supporting foils enables also elemental imaging by energy dispersive X-ray spectroscopy (EDX) with high spatial resolution. Valuable information on the elemental distribution in individual micro-, submicro- and even nanocapsules completes the "3D" high resolution morphological characterization at the same multimodal SEM/TSEM/EDX system.

New constraint on the existence of the µ+ → e+ γ decay.

The analysis of a combined data set, totaling 3.6 × 10(14) stopped muons on target, in the search for the lepton flavor violating decay µ(+) → e(+)γ is presented. The data collected by the MEG experiment at the Paul Scherrer Institut show no excess of events compared to background expectations and yield a new upper limit on the branching ratio of this decay of 5.7 × 10(-13) (90% confidence level). This represents a four times more stringent limit than the previous world best limit set by MEG.

Robust morphogenesis by chaotic dynamics.

This research illustrates that complex dynamics of gene products enable the creation of any prescribed cellular differentiation patterns. These complex dynamics can take the form of chaotic, stochastic, or noisy chaotic dynamics. Based on this outcome and previous research, it is established that a generic open chemical reactor can generate an exceptionally large number of different cellular patterns. The mechanism of pattern generation is robust under perturbations and it is based on a combination of Turing's machines, Turing instability and L. Wolpert's gradients. These results can help us to explain the formidable adaptive capacities of biochemical systems.

New limit on the lepton-flavor-violating decay µ+→e+γ.

We present a new result based on an analysis of the data collected by the MEG detector at the Paul Scherrer Institut in 2009 and 2010, in search of the lepton-flavor-violating decay µ(+)e(+)γ. The likelihood analysis of the combined data sample, which corresponds to a total of 1.8×10(14) muon decays, gives a 90% C.L. upper limit of 2.4×10(-12) on the branching ratio of the µ(+)→e(+)γ decay, constituting the most stringent limit on the existence of this decay to date.

Comparative study of multilayers used in monochromators for synchrotron-based coherent hard X-ray imaging.

A systematic study is presented in which multilayers of different composition (W/Si, Mo/Si, Pd/B(4)C), periodicity (from 2.5 to 5.5 nm) and number of layers have been characterized. In particular, the intrinsic quality (roughness and reflectivity) as well as the performance (homogeneity and coherence of the outgoing beam) as a monochromator for synchrotron radiation hard X-ray micro-imaging are investigated. The results indicate that the material composition is the dominating factor for the performance. By helping scientists and engineers specify the design parameters of multilayer monochromators, these results can contribute to a better exploitation of the advantages of multilayer monochromators over crystal-based devices; i.e. larger spectral bandwidth and high photon flux density, which are particularly useful for synchrotron-based micro-radiography and -tomography.

Impact of globule unfolding on dilational viscoelasticity of beta-lactoglobulin adsorption layers.

The dynamic surface dilational elasticity, surface pressure, and adsorbed amount of the mixed solutions of beta-lactoglobulin and guanidine hydrochloride were measured as a function of surface age and denaturant concentration. It was shown that the conformational transition from compact globules to disordered protein molecules in the surface layer leads to strong changes in the surface elasticity kinetic dependencies and thereby can be easily detected by measuring the surface dilational rheological properties. The corresponding changes of the kinetic dependencies of the surface pressure and adsorbed amount are not so pronounced but correlate with the results on surface dilational elasticity.

Competitive adsorption from mixed hen egg-white lysozyme/surfactant solutions at the air-water interface studied by tensiometry, ellipsometry, and surface dilational rheology.

The competitive adsorption at the air-water interface from mixed adsorption layers of hen egg-white lysozyme with a non-ionic surfactant (C10DMPO) was studied and compared to the mixture with an ionic surfactant (SDS) using bubble and drop shape analysis tensiometry, ellipsometry, and surface dilational rheology. The set of equilibrium and kinetic data of the mixed solutions is described by a thermodynamic model developed recently. The theoretical description of the mixed system is based on the model parameters for the individual components.

Biofriendly nanocomposite containers with inhibition properties for the protection of metallic surfaces.

An attempt to combine two 'green' compounds in nanocomposite microcontainers in order to increase protection properties of waterborne acryl-styrene copolymer (ASC) coatings has been made. N-lauroylsarcosine (NLS) served as a corrosion inhibitor, and linseed oil (LO) as a carrier-forming component. LO is compatible with this copolymer and can impart to the coating self-healing properties. For the evaluation of the protective performance, three types of coatings were compared. In the first two, NLS was introduced in the coating formulation in the forms of free powder and micro-containers filled with LO, correspondingly. The last one was a standard ASC coating without inhibitor at all. Low-carbon steel substrates were coated by these formulations by spraying and subjected subsequently to the neutral salt spray test according to DIN ISO 9227. Results of these tests as well as the data obtained by electrochemical study suggest that such containers can be used for the improvement of adhesion of ASC-based coatings to the substrate and for the enhancement of their protective performance upon integrity damage, whereas the barrier properties of intact coatings were decreased.

Composite interfacial layers containing micro-size and nano-size particles.

Surface layers of micro- and nanoparticles at fluid/liquid interfaces in absence and presence of surfactants are of large importance in the process of re-discovering Pickering systems, i.e. emulsions and foams stabilized by particles. The surface pressure/area isotherms of such layers can provide information about the properties of the used particles (dimensions, interfacial contact angles), the structure of interfacial layers, the interactions between the particles as well as about relaxation processes within the layers. For a correct description of Pi-A isotherms of composite surface layers containing particles the significant difference in size of these particles to that of solvent and surfactant molecules should be taken into account. Corresponding equations can be derived on the basis of the two-dimensional solution theory. The gained equations provide satisfactory agreement with experimental data and predict realistic values for the area of particles at the interface. Also equations of state and of the dilational elasticity for composite surface layers containing particles can be obtained in the framework of the presented methodology.

Polymer-surfactant complexes for microencapsulation of vitamin E and its release.

Microencapsulation of vitamin E directly from oil-in-water (o/w) emulsions was carried out by means of a novel practically relevant approach. For the first time, a preformed polyelectrolyte-surfactant complex (sodium polystyrene sulfonate/dodecyl trimethyl ammonium bromide) was simultaneously used as an electrosteric emulsion stabilizer and as a charged precursor for the following build up of microcapsules. Subsequently, a layer-by-layer technique was applied to emulsions leading to the formation of core-shell microcapsules with oily cores and polyelectrolyte shells. The effect of the complexes on the process of emulsion formation and on the stability and characteristics of the resulting emulsions was investigated by measurements of dynamic and equilibrium interfacial tension, size distribution (DLS) and interfacial charge (zeta-potential). The resulting microcapsules were characterized by confocal laser scanning microscopy (CLSM), Cryo-SEM, size distribution and zeta-potential measurements on each stage of the shell assembly. The release kinetics of vitamin E was monitored during the consecutive steps of the encapsulation procedure using UV-vis spectroscopy and showed the progressive enhancement of sustainability. The developed approach may be promising for the practical use in the cosmetic and food industry.

Ellipsometric study of nonionic polymer solutions.

The thickness and refractive index of adsorption films of poly(vinylpyrrolidone) (PVP) and poly(ethylene glycol) (PEG) were determined by null-ellipsometry at the air-aqueous solution interface. Both parameters, in the same way as the earlier studied dynamic surface elasticity and surface tension, exhibit rather abrupt changes when the concentration approaches the range of semidilute solutions. This behavior can be explained by the worsening of the solvent quality with increasing PEG concentration and by the PVP displacement from the surface by a contamination of high surface activity.

Relation between rheological properties and structural changes in monolayers of model lung surfactant under compression.

rSP-C surfactant monolayers spread on a native physiological model substrate show two plateau regions in the pi/A-isotherm. The first corresponds to the main phase transition in the monolayer from a LE to a LC phase. Its course is non-horizontal because of the complex composition of the lung surfactant. The second plateau, which is much more pronounced, cannot be attributed to a change of the phase state. Brewster angle microscopy images taken in this region show a sharp apparent decrease of the aggregation degree from the LE to the LC state. This process can be considered as a change in the monolayer orientation relative to the direction of the propagated light. Such a change can be the result of monolayer folding and formation of a thicker layer, which is supported by results of rheological measurements. The dilatation elasticity obtained from oscillating barrier and longitudinal wave measurements reveals a pure elastic behaviour with a steep increase in the second plateau region. Because of the insolubility of the pure lipid components, a possible explanation is squeezing protein components of rSP-C or its complexes with lipids out of the monolayer into the bulk.

Dynamics of protein and mixed protein/surfactant adsorption layers at the water/fluid interface.

The adsorption behaviour of proteins and systems mixed with surfactants of different nature is described. In the absence of surfactants the proteins mainly adsorb in a diffusion controlled manner. Due to lack of quantitative models the experimental results are discussed partly qualitatively. There are different types of interaction between proteins and surfactant molecules. These interactions lead to protein/surfactant complexes the surface activity and conformation of which are different from those of the pure protein. Complexes formed with ionic surfactants via electrostatic interaction have usually a higher surface activity, which becomes evident from the more than additive surface pressure increase. The presence of only small amounts of ionic surfactants can significantly modify the structure of adsorbed proteins. With increasing amounts of ionic surfactants, however, an opposite effect is reached as due to hydrophobic interaction and the complexes become less surface active and can be displaced from the interface due to competitive adsorption. In the presence of non-ionic surfactants the adsorption layer is mainly formed by competitive adsorption between the compounds and the only interaction is of hydrophobic nature. Such complexes are typically less surface active than the pure protein. From a certain surfactant concentration of the interface is covered almost exclusively by the non-ionic surfactant. Mixed layers of proteins and lipids formed by penetration at the water/air or by competitive adsorption at the water/chloroform interface are formed such that at a certain pressure the components start to separate. Using Brewster angle microscopy in penetration experiments of proteins into lipid monolayers this interfacial separation can be visualised. A brief comparison of the protein adsorption at the water/air and water/n-tetradecane shows that the adsorbed amount at the water/oil interface is much stronger and the change in interfacial tension much larger than at the water/air interface. Also some experimental data on the dilational elasticity of proteins at both interfaces measured by a transient relaxation technique are discussed on the basis of the derived thermodynamic model. As a fast developing field of application the use of surface tensiometry and rheometry of mixed protein/surfactant mixed layers is demonstrated as a new tool in the diagnostics of various diseases and for monitoring the progress of therapies.

Experimental studies on the geometrical characteristics determining the system behavior of surface tension autooscillations.

Autooscillation of the surface tension is a phenomenon related to Marangoni instability periodically arising and fading by dissolution of a surfactant droplet under a water-air interface. A detailed experimental investigation was performed to clear up the influence of the system geometry on development and characteristics of autooscillations. It was found that the aspect ratio is an additional dimensionless parameter that determines the system behavior equally to the Marangoni number. The influence of the cell diameter, capillary immersion depth, and droplet radius on the autooscillation period and amplitude was studied as well.

Beta-casein bilayer adsorption at the solution/air interface: experimental evidences and theoretical description.

Ellipsometric and surface pressure studies of beta-casein adsorption layers at the water/air interface support the idea of a model that assumes the formation of a second layer adjacent to the primary adsorption layer. A thermodynamic model describes the concentration behavior of the surface pressure and the adsorbed amount with one and the same set of model parameters over the entire concentration range studied.

Structural and functional changes of blood-brain barrier and indication of prion amyloid filaments in experimental amyotrophic leucospongiosis.

The reproduction of amyotrophic leukospongiosis (AL) agent in the central nervous system (CNS) of guinea pigs was accompanied by local disturbance of blood-brain barrier (BBB), which manifested in passing of horseradish peroxidase through the endothelium of some of capillaries (10-14%). The disturbance of BBB function coincided with dystrophic changes in a number of pericapillary astrocyte foot processes and in pericytes. In the walls of altered vessels we observed congophilic (amyloid) deposits, which formed immunocomplexes with monoclonal antibodies to the AL agent protein PrP 27-30 kD. By electron microscopic the deposits consisted of masses of filaments with diameter of 5-10 nm located between the basement membrane and endothelium of the vessels.

Punctuated evolution and robustness in morphogenesis.

This paper presents an analytic approach to the pattern stability and evolution problem in morphogenesis. The approach used here is based on the ideas from the gene and neural network theory. We assume that gene networks contain a number of small groups of genes (called hubs) controlling morphogenesis process. Hub genes represent an important element of gene network architecture and their existence is empirically confirmed. We show that hubs can stabilize morphogenetic pattern and accelerate the morphogenesis. The hub activity exhibits an abrupt change depending on the mutation frequency. When the mutation frequency is small, these hubs suppress all mutations and gene product concentrations do not change, thus, the pattern is stable. When the environmental pressure increases and the population needs new genotypes, the genetic drift and other effects increase the mutation frequency. For the frequencies that are larger than a critical amount the hubs turn off; and as a result, many mutations can affect phenotype. This effect can serve as an engine for evolution. We show that this engine is very effective: the evolution acceleration is an exponential function of gene redundancy. Finally, we show that the Eldredge-Gould concept of punctuated evolution results from the network architecture, which provides fast evolution, control of evolvability, and pattern robustness. To describe analytically the effect of exponential acceleration, we use mathematical methods developed recently for hard combinatorial problems, in particular, for so-called k-SAT problem, and numerical simulations.