Ionization via Chaos Assisted Tunneling

A simple example of quantum transport in a classically chaotic system is studied. It consists in a single state lying on a regular island (a stable primary resonance island) which may tunnel into a chaotic sea and further escape to infinity via chaotic diffusion. The specific system is realistic : it is the hydrogen atom exposed to either linearly or circularly polarized microwaves. We show that the combination of tunneling followed by chaotic diffusion leads to peculiar statistical fluctuation properties of the energy and the ionization rate, especially to enhanced fluctuations compared to the purely chaotic case. An appropriate random matrix model, whose predictions are analytically derived, describes accurately these statistical properties.Comment: 30 pages, 11 figures, RevTeX and postscript, Physical Review E in pres

Investigation of 14.1 MeV neutrons interaction with C, Mg, Cr

This paper is dedicated to n+12C, n+24Mg, n+52Cr -reactions investigation at 14.1 MeV neutron energy. Characteristics of these reactions have been calculated using TALYS code to estimate perspectives of using of this code in data interpretation in the TANGRA project. This project is performed in Frank Laboratory of Neutron Physics (FLNP JINR) to investigate properties of (n,xγ)-type reactions, important for fundamental and practical applications

The host response to the probiotic Escherichia coli strain Nissle 1917: Specific up-regulation of the proinflammatory chemokine MCP-1

BACKGROUND: The use of live microorganisms to influence positively the course of intestinal disorders such as infectious diarrhea or chronic inflammatory conditions has recently gained increasing interest as a therapeutic alternative. In vitro and in vivo investigations have demonstrated that probiotic-host eukaryotic cell interactions evoke a large number of responses potentially responsible for the effects of probiotics. The aim of this study was to improve our understanding of the E. coli Nissle 1917-host interaction by analyzing the gene expression pattern initiated by this probiotic in human intestinal epithelial cells. METHODS: Gene expression profiles of Caco-2 cells treated with E. coli Nissle 1917 were analyzed with microarrays. A second human intestinal cell line and also pieces of small intestine from BALB/c mice were used to confirm regulatory data of selected genes by real-time RT-PCR and cytometric bead array (CBA) to detect secretion of corresponding proteins. RESULTS: Whole genome expression analysis revealed 126 genes specifically regulated after treatment of confluent Caco-2 cells with E. coli Nissle 1917. Among others, expression of genes encoding the proinflammatory molecules monocyte chemoattractant protein-1 ligand 2 (MCP-1), macrophage inflammatory protein-2 alpha (MIP-2α) and macrophage inflammatory protein-2 beta (MIP-2β) was increased up to 10 fold. Caco-2 cells cocultured with E. coli Nissle 1917 also secreted high amounts of MCP-1 protein. Elevated levels of MCP-1 and MIP-2α mRNA could be confirmed with Lovo cells. MCP-1 gene expression was also up-regulated in mouse intestinal tissue. CONCLUSION: Thus, probiotic E. coli Nissle 1917 specifically upregulates expression of proinflammatory genes and proteins in human and mouse intestinal epithelial cells

Response function of a BGO detector for γ-rays with energies in the range from 0.2 MeV to 8 MeV

427-430This work is devoted to determination of the response function of a BGO detector of γ-rays, which is used in experiments aimed at investigation of inelastic scattering of neutrons with energies of 14.1 MeV on various nuclei. A function is constructed to describe the Monte-Carlo simulated response of a gamma-detector, which allows taking into account all possible mechanisms of interaction of γ-rays with matter, as well as the geometric parameters of the detector. For all components of the function, an analytical form of their energy dependencies is selected and its parameters are determined in the case of registration of γ-quanta with energies in the range from 0.2 MeV to 8 MeV

Response function of a BGO detector for γ-rays with energies in the range from 0.2 MeV to 8 MeV

This work is devoted to determination of the response function of a BGO detector of γ-rays, which is used in experiments aimed at investigation of inelastic scattering of neutrons with energies of 14.1 MeV on various nuclei. A function is constructed to describe the Monte-Carlo simulated response of a gamma-detector, which allows taking into account all possible mechanisms of interaction of γ-rays with matter, as well as the geometric parameters of the detector. For all components of the function, an analytical form of their energy dependencies is selected and its parameters are determined in the case of registration of γ-quanta with energies in the range from 0.2 MeV to 8 MeV