Density functional simulation of small Fe nanoparticles

We calculate from first principles the electronic structure, relaxation and magnetic moments in small Fe particles, applying the numerical local orbitals method in combination with norm-conserving pseudopotentials. The accuracy of the method in describing elastic properties and magnetic phase diagrams is tested by comparing benchmark results for different phases of crystalline iron to those obtained by an all-electron method. Our calculations for the bipyramidal Fe_5 cluster qualitatively and quantitatively confirm previous plane-wave results that predicted a non-collinear magnetic structure. For larger bcc-related (Fe_35) and fcc-related (Fe_38, Fe_43, Fe_62) particles, a larger inward relaxation of outer shells has been found in all cases, accompanied by an increase of local magnetic moments on the surface to beyond 3 mu_B.Comment: 15 pages with 6 embedded postscript figures, updated version, submitted to Eur.Phys.J.

Generating low-temperature glow discharge plasma in the atmospheric pressure helium after spark breakdown: Modelling plasma with the prescribed properties for biomedical applications

This paper concerns computational modelling of the low-temperature glow discharge plasma in the atmospheric pressure helium after spark breakdown and research on the dependence of a spatial distribution of plasma on the initial conditions of discharge and parameters of the external electric circuit. This study analysed the influence of the initial distribution of a space charge on the generation of the glow discharge plasma after the spark breakdown between flat electrodes by means of a 2D-axial symmetric model of the atmospheric pressure helium plasma in the drift-diffusion approximation. With the discharge current of 1–12 mA, the solution for a quasi-steady state of plasma is obtained. The dependence of a type of this discharge mode on the parameters of the external electric circuit and coefficient of the secondary cathode emission is studied

Algebras with Operator and Campbell--Hausdorff Formula

We introduce some new classes of algebras and estabilish in these algebras Campbell--Hausdorff like formula. We describe the application of these constructions to the problem of the connectivity of the Feynman graphs corresponding to the Green functions in Quantum Fields Theory.Comment: 12 page

Preanalytical features of the determination of circulating microRNAs as new specific biomarkers of the body’s response to physical activity

MicroRNAs are small non-coding single-stranded RNAs, 18 to 25 nucleotides long, they regulate gene expression at the post-transcriptional level through specific binding to the target mRNA, leading to its degradation. In recent decades, the development of technologies for determining the expression profiles of miRNAs has become an important part of research projects, and the role of miRNAs as potential highly informative molecular biomarkers of various physiological and pathological processes in the body is actively explored by the scientific community. In particular, physical activity is an important modifying factor for circulating miRNAs. Unlike classical blood biochemical parameters, which can change over time depending on the temperature and storage conditions of the sample, microRNAs remain stable during storage and even after multiple freeze-thaw cycles, which makes them an attractive and easily accessible target for detection. However, the determination of the microRNA expression profile in clinical practice is still difficult due to the high heterogeneity of analytical procedures used for testing. In sports medicine, the preanalytical stage is especially important, since often the conditions for sampling are not standardized and can affect the analysis result. This review shows the role of miRNAs as new sensitive biomarkers of the effectiveness of the training process and regulators of the body’s response to physical activity, and also discusses some preanalytical aspects of the analysis of miRNA expression profiles

Semiempirical Hartree-Fock calculations for KNbO3

In applying the semiempirical intermediate neglect of differential overlap (INDO) method based on the Hartree-Fock formalism to a cubic perovskite-based ferroelectric material KNbO3, it was demonstrated that the accuracy of the method is sufficient for adequately describing the small energy differences related to the ferroelectric instability. The choice of INDO parameters has been done for a system containing Nb. Based on the parametrization proposed, the electronic structure, equilibrium ground state structure of the orthorhombic and rhombohedral phases, and Gamma-TO phonon frequencies in cubic and rhombohedral phases of KNbO3 were calculated and found to be in good agreement with the experimental data and with the first-principles calculations available.Comment: 7 pages, 2 Postscript figures, uses psfig.tex. To be published in Phys.Rev.B 54, No.4 (1996

Fast electrochemical membrane actuator:Design, fabrication and preliminary testing

An actuator based on water electrolysis with a fast change of voltage polarity is presented. It demonstrates a new actuation principle allowing significant increase the operation frequency of the device due to fast termination of the produced gas. The actuator consists of a working chamber with metallic electrodes and supplying channels filled with an electrolyte. The chamber is formed in a layer of SU-8 and covered by a flexible polydimethylsiloxane membrane, which deforms as the pressure in the chamber increases. Design, fabrication procedure, and first tests of the actuator are described

Comparison of microRNA expression profiles of athletes involved in endurance sports and non-athletic volunteers using a hypoxia signaling pathway panel

In recent years, interest in the search for new potential molecular biomarkers to assess the effectiveness of the training process in elite sports, various pathologies caused by overload, and abuse of prohibited substances has reached an unprecedented level. MicroRNAs that regulate the processes of metabolism, differentiation, proliferation, and apoptosis of cells at the post-transcriptional level are the most valuable candidates for use in this regard. They are found in all biological fluids of the human body, are stable during long-term storage and resistant to changes in environmental conditions. It is known that changes in the miRNA expression profile are closely associated with physical activity, as well as with the administration of recombinant hormones, erythropoiesis-stimulating agents, and other substances and methods that improve sports performance, which are prohibited by the World Anti-Doping Agency (WADA).Objective: In this study, plasma samples from athletes involved in endurance sports (race walking) and non-athletic volunteers were analyzed using a hypoxia signaling pathway panel to identify hypoxia candidate markers.Materials and methods: Expression profiles of plasma circulating miRNAs were assessed by reverse transcription followed by real-time quantitative polymerase chain reaction (RT Q-PCR). The obtained data were subjected to statistical processing using the CFX Manager Software v3.1 program.Results: Three potential microRNA markers were identified: hsa-miR-210-3p, hsa-miR-320a and hsa-miR-935 (increased in athletes by 61.6 times, 51.8 and 41.0 times, respectively) — of physiological response to the training, load, which may be associated with the emergence of hypoxia during endurance training.Conclusion: We have obtained preliminary data on differences in the expression profiles of circulating miRNAs in healthy non-athletic volunteers and professional athletes in the out-of-competition period. In the future, it is planned to expand the sample of studied blood plasma samples and compare the expression profiles of circulating microRNAs in athletes in competition and out-of-competition periods, as well as to compare the expression profiles of circulating microRNAs during aerobic and anaerobic loads. In addition, it is of interest to analyze changes in the expression levels of circulating miRNAs when using hypoxia mimetics applied to improve sports performance

Estimates for parameters and characteristics of the confining SU(3)-gluonic field in an η′\eta^\prime-meson

The confinement mechanism proposed earlier by the author is applied to estimate the possible parameters of the confining SU(3)-gluonic field in an $\eta^\prime$-meson. For this aim the electric form factor of an $\eta^\prime$-meson is nonperturbatively computed in an explicit analytic form. The estimates obtained are also consistent with the width of the electromagnetic decay $\eta^\prime\to2\gamma$. The corresponding estimates of the gluon concentrations, electric and magnetic colour field strengths are also adduced for the mentioned field at the scales of the meson under consideration.Comment: 20 pages, LaTe

Classification of the line-soliton solutions of KPII

In the previous papers (notably, Y. Kodama, J. Phys. A 37, 11169-11190 (2004), and G. Biondini and S. Chakravarty, J. Math. Phys. 47 033514 (2006)), we found a large variety of line-soliton solutions of the Kadomtsev-Petviashvili II (KPII) equation. The line-soliton solutions are solitary waves which decay exponentially in $(x,y)$-plane except along certain rays. In this paper, we show that those solutions are classified by asymptotic information of the solution as $|y| \to \infty$. Our study then unravels some interesting relations between the line-soliton classification scheme and classical results in the theory of permutations.Comment: 30 page