Quantum memory for light via stimulated off-resonant Raman process: beyond the three-level Lambda-scheme approximation

We consider a quantum memory scheme based on the conversion of a signal pulse into a long-lived spin coherence via stimulated off-resonant Raman process. For a storing medium consisting of alkali atoms, we have calculated the Autler-Townes resonance structure created by a strong control field. By taking into account the upper hyperfine states of the D1 optical transition, we show important deviations from the predictions of the usual three-level Lambda-scheme approximation and we demonstrate an enhancement of the process for particular detunings of the control. We estimate the memory efficiency one can obtain using this configuration.Comment: 8 pages, 6 figure

Electromagnetically induced transparency in inhomogeneously broadened Lambda-transition with multiple excited levels

Electromagnetically induced transparency (EIT) has mainly been modelled for three-level systems. In particular, a considerable interest has been dedicated to the Lambda-configuration, with two ground states and one excited state. However, in the alkali-metal atoms, which are commonly used, hyperfine interaction in the excited state introduces several levels which simultaneously participate in the scattering process. When the Doppler broadening is comparable with the hyperfine splitting in the upper state, the three-level Lambda model does not reproduce the experimental results. Here we theoretically investigate the EIT in a hot vapor of alkali-metal atoms and demonstrate that it can be strongly reduced due to the presence of multiple excited levels. Given this model, we also show that a well-designed optical pumping enables to significantly recover the transparency

Ferroelectric Nanotubes

We report the independent invention of ferroelectric nanotubes from groups in several countries. Devices have been made with three different materials: lead zirconate-titanate PbZr1-xTixO3 (PZT); barium titanate BaTiO3; and strontium bismuth tantalate SrBi2Ta2O9 (SBT). Several different deposition techniques have been used successfully, including misted CSD (chemical solution deposition) and pore wetting. Ferroelectric hysteresis and high optical nonlinearity have been demonstrated. The structures are analyzed via SEM, TEM, XRD, AFM (piezo-mode), and SHG. Applications to trenching in Si dynamic random access memories, ink-jet printers, and photonic devices are discussed. Ferroelectric filled pores as small as 20 nm in diameter have been studied

Local cellular immune response in chronic periodontitis

Microflora of the oral cavity forms a biofilm that induces response of immune system at the mucous membranes. Transition to periodontal lesion is provided by certain classes of resident mucosal immune cells and inflammatory/immune cells migrating to the periodont. In periodontal diseases, Th1, Th2, Th17, Treg are detected. T regulatory cells (Tregs) are proven to comprise the main anti-inflammatory cell population. Th17 cells and Treg cells play an important role in osteoclast differentiation. IL-17 secreted by Th17 cells affects osteoclastogenesis and may induce macrophages to enhance the local inflammatory response. In this regard, the aim of our work was to identify the local immune cells in oral cavity which are associated with severity of chronic generalized periodontitis. The oral cavity cells from 58 persons aged 38-65 years of both sexes in their mature age with a diagnosis of «chronic periodontitis» were examined by means of flow cytofluorometry. When determining levels of CD64+CD16+CD14- neutrophils in the patients with periodontitis of different severity, a statistically significant increase of this cell population was revealed upon development of this disease. In mild cases of periodontitis, a significant increase of relative CD64+CD16+CD14-  neutrophil contents was revealed (Me = 36.16%, p < 0.05) compared to the control group (Me = 7.7%, Q0.25 = 2.4%, Q0.75 = 12%). When assessing relative numbers of CD14+ monocytes in periodontitis of various severity, we revealed a significant increase in the number of these cells in severe cases. When studying levels of regulatory T lymphocytes (CD4+CD25+CD127low) in periodontitis of different severity, we revealed significantly decreased amounts of this cell population during development of the disease. In mild cases of periodontitis, a decreased level of CD4+CD25+CD127low cells (p < 0.05, Me = 1356 cells/ml) was revealed, as compared with control group (Me = 10666 cells/ml). Although the concentration of CD4+CD25+CD127low (Me = 4709 cells/ml) in the patients with moderate periodontitis was higher than the values in milder cases, the range of the main values was comparable and lower, than in control group. In severe periodontitis, a significantly decreased concentration of regulatory T lymphocytes was revealed (Me = 2637 cells/ml). These results confirm the anti-inflammatory regulatory function of Tregs. Understanding the osteo-immune mechanisms of bone remodeling control will help to understand the pathophysiology of accelerated bone loss observed in severe chronic periodontitis

АНАЛИЗ И ДИАГНОСТИКА УРОВНЕЙ УЧЕБНО-ИНФОРМАЦИОННЫХ УМЕНИЙ СТУДЕНТОВ 1-ОГО КУРСА ЕСТЕСТВЕННО-НАУЧНОГО ФАКУЛЬТЕТА 2018–2019 ГОДА

This article diagnoses and analyzes the educational and information skills of first-year students. В данной статье диагностируются и анализируются учебно-информационные умения студентов первого курса.

Hernia or hernia Defect? Experimental herniology Models in Laboratory Animals

Hernias of the anterior abdominal wall remain one of the most common surgery pathologies. There is no unified approach to modeling anterior abdominal wall hernias in the world scientific community. In order to systematize the available knowledge in this field and to contribute to the formation of a unified idea of how to create a hernia model in a laboratory animal, it seems logical to study the accumulated experience of researchers in the field of experimental herniology. We found out that hernia defects generally modeled on male laboratory rats. To understand the tissue reaction to the prosthetic material a fenestration was performed in the anterior abdominal wall (including peritoneum) except for the skin and subcutaneous fat. A replacement or prosthetic material tailored to the fenestration was sutured end-to-end into the abdominal wall. We chose laboratory rats because they are easy to take care of and cheaper than larger laboratory animals