230 research outputs found

    Direct experimental observation of binary agglomerates in complex plasmas

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    A defocusing imaging technique has been used as a diagnostic to identify binary agglomerates (dimers) in complex plasmas. Quasi-two-dimensional plasma crystal consisting of monodisperse spheres and binary agglomerates has been created where the agglomerated particles levitate just below the spherical particles without forming vertical pairs. Unlike spherical particles, the defocused images of binary agglomerates show distinct, stationary/periodically rotating interference fringe patterns. The results can be of fundamental importance for future experiments on complex plasmas

    First direct measurement of optical phonons in 2D plasma crystals

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    Spectra of phonons with out-of-plane polarization were studied experimentally in a 2D plasma crystal. The dispersion relation was directly measured for the first time using a novel method of particle imaging. The out-of-plane mode was proven to have negative optical dispersion, comparison with theory showed good agreement. The effect of the plasma wakes on the dispersion relation is briefly discussed.Comment: submitted to Physical Review Letter

    Wave mode coupling due to plasma wakes in two-dimensional plasma crystals: In-depth view

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    Experiments with two-dimensional (2D) plasma crystals are usually carried out in rf plasma sheaths, where the interparticle interactions are modified due to the presence of plasma wakes. The wake-mediated interactions result in the coupling between wave modes in 2D crystals, which can trigger the mode-coupling instability and cause melting. The theory predicts a number of distinct fingerprints to be observed upon the instability onset, such as the emergence of a new hybrid mode, a critical angular dependence, a mixed polarization, and distinct thresholds. In this paper we summarize these key features and provide their detailed discussion, analyze the critical dependence on experimental parameters, and highlight the outstanding issues

    Direct observation of mode-coupling instability in two-dimensional plasma crystals

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    Dedicated experiments on melting of 2D plasma crystals were carried out. The melting was always accompanied by spontaneous growth of the particle kinetic energy, suggesting a universal plasma-driven mechanism underlying the process. By measuring three principal dust-lattice (DL) wave modes simultaneously, it is unambiguously demonstrated that the melting occurs due to the resonance coupling between two of the DL modes. The variation of the wave modes with the experimental conditions, including the emergence of the resonant (hybrid) branch, reveals exceptionally good agreement with the theory of mode-coupling instability.Comment: 4 pages, submitted to Physical Review Letter

    Nonlinear regime of the mode-coupling instability in 2D plasma crystals

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    The transition between linear and nonlinear regimes of the mode-coupling instability (MCI) operating in a monolayer plasma crystal is studied. The mode coupling is triggered at the centre of the crystal and a melting front is formed, which travels through the crystal. At the nonlinear stage, the mode coupling results in synchronisation of the particle motion and the kinetic temperature of the particles grows exponentially. After melting of the crystalline structure, the mean kinetic energy of the particles continued to grow further, preventing recrystallisation of the melted phase. The effect could not be reproduced in simulations employing a simple point-like wake model. This shows that at the nonlinear stage of the MCI a heating mechanism is working which was not considered so far.Comment: 6 pages, 4 figure

    Itaconate-mediated inhibition of succinate dehydrogenase regulates cytokine production in LPS-induced inflammation

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    Itaconate is an immunoregulatory metabolite produced by myeloid cells and plays a key role in the regulation of the immune response. Itaconate, on the one hand, is able to suppress the activity of succinate dehydrogenase (SDH), thereby making a significant contribution to the metabolic reprogramming of the cell. On the other hand, itaconate can regulate the activity of a number of transcription factors and transcription regulators, thereby affecting gene expression. In most experimental studies, itaconate has been characterized predominantly as an anti-inflammatory agent. In particular, itaconate produced by activated macrophages inhibits the production of cytokines TNF, IL-1b, IL-6, IL-10. However, some evidence suggests a pro- inflammatory role for itaconate in a number of mouse disease models. Thus, the deletion of the Acod1 gene responsible for the production of itaconate leads to the suppression of the production of TNF and IL-6 in the mouse polymicrobial sepsis model, which means that in the context of inflammation in vivo, itaconate can act as an inducer of pro-inflammatory cytokines. The mechanism of itaconate regulation of cytokine production in systemic inflammation remains unexplored. In this work, we have shown that injection of itaconate and its derivative dimethyl itaconate into mice, followed by induction of inflammation by bacterial lipopolysaccharide (LPS), leads to changes in the content of cytokines in the blood. Interestingly, the systemic production of IL-6 and IL-10 in response to itaconate is increased, contrary to the results previously obtained in cell cultures. At the same time, IFNg production, on the contrary, is suppressed. Apparently, itaconate regulates the production of cytokines in vivo by suppressing the activity of SDH. Injection of the SDH inhibitor, dimethylmalonate, followed by induction of inflammation in mice, results in similar changes in blood cytokines observed in response to itaconate: increased production of IL-6, IL-10 and suppression of IFNg production. On the contrary, the addition of succinate, a SDH substrate, leads to the opposite effect on cytokine production. Thus, it can be assumed that the observed effects of itaconate on cytokine production in the model of LPS-induced inflammation are mediated by its ability to inhibit SDH. These results help to understand the controversial role of itaconate in inflammation and shed light on a previously undescribed relationship between SDH and cytokine production in inflammation in vivo

    Shear flow in a three-dimensional complex plasma in microgravity conditions

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    Shear flow in a three-dimensional complex plasma was experimentally studied in microgravity conditions using Plasmakristall-4 (PK-4) instrument on board the International Space Station (ISS). The shear flow was created in an extended suspension of microparticles by applying the radiation pressure force of the manipulation-laser beam. Individual particle trajectories in the flow were analyzed and from these, using the Navier-Stokes equation, an upper estimate of the complex plasma's kinematic viscosity was calculated in the range of 0.20.2--6.7 mm2/s6.7~{\rm mm^2/s}. This estimate is much lower than previously reported in ground-based experiments with 3D complex plasmas. Possible reasons of this difference are discussed.Comment: 5 pages, 4 figure

    Molecular-genetic aspects of the endometrium state on the day of the tentative implantation window in women with recurrent miscarriage in the programs of assisted reproductive technologies

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    Golovatyuk K. P., Nosenko O. M., Makshayeva E. T., Trofimov D. Yu., Donnikov A. E., Kolin V. V. Molecular-genetic aspects of the endometrium state on the day of the tentative implantation window in women with recurrent miscarriage in the programs of assisted reproductive technologies. Journal of Education, Health and Sport. 2017;7(9):621-626. eISSN 2391-8306. DOI http://dx.doi.org/10.5281/zenodo.1068361 http://ojs.ukw.edu.pl/index.php/johs/article/view/5076 The journal has had 7 points in Ministry of Science and Higher Education parametric evaluation. Part B item 1223 (26.01.2017). 1223 Journal of Education, Health and Sport eISSN 2391-8306 7 © The Authors 2017; This article is published with open access at Licensee Open Journal Systems of Kazimierz Wielki University in Bydgoszcz, Poland Open Access. This article is distributed under the terms of the Creative Commons Attribution Noncommercial License which permits any noncommercial use, distribution, and reproduction in any medium, provided the original author(s) and source are credited. This is an open access article licensed under the terms of the Creative Commons Attribution Non Commercial License (http://creativecommons.org/licenses/by-nc/4.0/) which permits unrestricted, non commercial use, distribution and reproduction in any medium, provided the work is properly cited. This is an open access article licensed under the terms of the Creative Commons Attribution Non Commercial License (http://creativecommons.org/licenses/by-nc/4.0/) which permits unrestricted, non commercial use, distribution and reproduction in any medium, provided the work is properly cited. The authors declare that there is no conflict of interests regarding the publication of this paper. Received: 15.08.2017. Revised: 20.09.2017. Accepted: 29.09.2017. MOLECULAR-GENETIC ASPECTS OF THE ENDOMETRIUM STATE ON THE DAY OF THE tentative IMPLANTATION WINDOW IN WOMEN WITH recurrent miscarriage IN THE PROGRAMS OF ASSISTED REPRODUCTIVE TECHNOLOGIES 1K. P. Golovatyuk, 2O. M. Nosenko, 1E. T. Makshayeva, 3D. Yu. Trofimov, 4A. E. Donnikov, 3V. V. Kolin 1Limited Liability Company Medical Center for Reproductive Health "Gameta", Odessa, Ukraine; 2Odessa National Medical University, Ukraine; 3Limited Liability Company "NPF DNA-Technology", Moscow, Russia; 4FGBU Scientific Center for Obstetrics, Gynecology and Perinatology. named after acad. V.I. Kulakov Ministry of Health care and Social Development of Russia, Moscow, Russia; e-mail: [email protected] Abstract More than 50% of pregnant women after the programs of assisted reproductive technologies (ART) face the problem of recurrent miscarriage (RMC), especially in the first trimester. Significant role in the development of RMC has infectious factor and chronic inflammation in the endometrium. The aim: to reveal the peculiarities of immune response mRNA genes of the inflammatory component expression in the period of the tentative implantation window (TIW) in women with RMC in ART programs. Material and methods. The main group consisted of 240 patients with RMC in ART programs; the control group included 100 conditionally healthy fertile women. On the ground of PCR reverse transcription, the mRNA of the IL-1β, IL-2, IL-10, Foxp3, TLR9, IL-2Rα cytokine genes was examined in endometrial samples obtained with the help of biopsy on the TIW day. Results. Analysis of the transcriptional profile of the immune response genes in the endometrium on TIW day revealed that the relative level of mRNA expression of the IL-1β, IL-2, Foxp3, TLR9, IL-2Rα genes did not differ significantly in the main and control groups. Statistically significant decrease in mRNA expression of IL-10 gene was observed in women with RPL. Conclusions. A feature of mRNA expression of the inflammatory component of the immune response in TIW period in women with RMC in ART programs is a decrease in the expression level of the IL-10 gene mRNA, which may be one of the reasons for the unfavorable outcomes of the onset pregnancy. Key words: recurrent miscarriage, assisted reproductive technologies, immune response, reverse transcription-polymerase chain reaction, tentative implantation window

    Immunometabolic changes in macrophages in response to house dust mite extract

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    To date, much remains unclear about the pathogenesis of asthma, one of the most common chronic and highly heterogenic diseases of the respiratory system. The lack of specific and highly effective therapy in case of certain asthma subtypes requires the search for new approaches to treatment. One possible approach would be to influence the metabolism and immune functions of myeloid cells. This approach finds its application in the treatment of cancer and other diseases in the pathogenesis of which macrophages play an important role. It was shown that the pathogenesis of allergic asthma in response to one of the most common allergens, house dust mite, is due to a metabolic TNF-mediated reprogramming of alveolar macrophages. This suggests that influencing the process of TNF production or metabolic adaptations with specific blockers may also lead to a reduction in the symptoms of the course of the disease as a whole. In this work, we experimentally tested whether the previously obtained phenotype that occurs in macrophages in response to HDM cultured in DMEM is preserved if cells are cultured under more physiologically relevant conditions: in a medium closely related in composition to blood plasma. We also analyzed open databases of alveolar macrophages sequencing obtained from patients with asthma or from the lungs of mice in an HDM-induced asthma model in order to correlate specific immunometabolic changes. It was found that macrophages cultured under conditions close to physiological, simultaneously increase the rates of respiration and glycolysis, and also produce TNF in response to HDM. The observed phenotype is consistent with transcriptomic analyzes performed on human and mouse samples, which revealed an increase in the expression of genes related to glycolysis, oxidative phosphorylation, and the TNF signaling pathway. Thus, the data confirm the relevance of the phenotype obtained in vitro to the changes occurring in the in vivo system. However, functional verification at the level of metabolites, proteins and changes in metabolic activity is also required. In addition, it remains to be established how the blocking of individual metabolic pathways affects the features of the functional macrophage phenotype that occurs in response to HDM, and whether this effect can alleviate asthma symptoms
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