190 research outputs found

    Eisenhart Lift of 22--Dimensional Mechanics

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    The Eisenhart lift is a variant of geometrization of classical mechanics with dd degrees of freedom in which the equations of motion are embedded into the geodesic equations of a Brinkmann-type metric defined on (d+2)(d+2)-dimensional spacetime of Lorentzian signature. In this work, the Eisenhart lift of 22-dimensional mechanics on curved background is studied. The corresponding 44-dimensional metric is governed by two scalar functions which are just the conformal factor and the potential of the original dynamical system. We derive a conformal symmetry and a corresponding quadratic integral, associated with the Eisenhart lift. The energy--momentum tensor is constructed which, along with the metric, provides a solution to the Einstein equations. Uplifts of 22-dimensional superintegrable models are discussed with a particular emphasis on the issue of hidden symmetries. It is shown that for the 22-dimensional Darboux--Koenigs metrics, only type I can result in Eisenhart lifts which satisfy the weak energy condition. However, some physically viable metrics with hidden symmetries are presented.Comment: 20 page

    CD19依存性B細胞のシグナル閾値はtight skin mouseにおける皮膚の線維化及び自己免疫に関与する

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    取得学位 : 博士(医学), 学位授与番号 : 医博甲第1564号, 学位授与年月日 : 平成15年3月25日, 学位授与大学 : 金沢大

    The Possible Role of TASK Channels in Rank-Ordered Recruitment of Motoneurons in the Dorsolateral Part of the Trigeminal Motor Nucleus.

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    Because a rank-ordered recruitment of motor units occurs during isometric contraction of jaw-closing muscles, jaw-closing motoneurons (MNs) may be recruited in a manner dependent on their soma sizes or input resistances (IRs). In the dorsolateral part of the trigeminal motor nucleus (dl-TMN) in rats, MNs abundantly express TWIK (two-pore domain weak inwardly rectifying K channel)-related acid-sensitive-K(+) channel (TASK)-1 and TASK3 channels, which determine the IR and resting membrane potential. Here we examined how TASK channels are involved in IR-dependent activation/recruitment of MNs in the rat dl-TMN by using multiple methods. The real-time PCR study revealed that single large MNs (>35 μm) expressed TASK1 and TASK3 mRNAs more abundantly compared with single small MNs (15-20 μm). The immunohistochemistry revealed that TASK1 and TASK3 channels were complementarily distributed in somata and dendrites of MNs, respectively. The density of TASK1 channels seemed to increase with a decrease in soma diameter while there were inverse relationships between the soma size of MNs and IR, resting membrane potential, or spike threshold. Dual whole-cell recordings obtained from smaller and larger MNs revealed that the recruitment of MNs depends on their IRs in response to repetitive stimulation of the presumed Ia afferents. 8-Bromoguanosine-cGMP decreased IRs in small MNs, while it hardly changed those in large MNs, and subsequently decreased the difference in spike-onset latency between the smaller and larger MNs, causing a synchronous activation of MNs. These results suggest that TASK channels play critical roles in rank-ordered recruitment of MNs in the dl-TMN

    Effect of Visual Information on Active Touch During Mirror Visual Feedback

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    Several studies have demonstrated that observation of a dummy or mirror-reflected hand being stroked or moving at the same time as the hidden hand evokes a feeling that the dummy hand is one’s own, such as the rubber hand illusion (RHI) and mirror visual feedback (MVF). Under these conditions, participants also report sensing the tactile stimulation applied to the fake hands, suggesting that tactile perception is modulated by visual information during the RHI and MVF. Previous studies have utilized passive stimulation conditions; however, active touch is more common in real-world settings. Therefore, we investigated whether active touch is also modulated by visual information during an MVF scenario. Twenty-three participants (13 men and 10 women; mean age ± SD: 21.6 ± 2.0 years) were required to touch a polyurethane pad with both hands synchronously, and estimate the hardness of the pad while observing the mirror reflection. When participants observed the mirror reflection of the other hand pushing a softer or harder pad, perceived hardness estimates were significantly biased toward softer or harder, respectively, even though the physical hardness of the pad remained constant. Furthermore, perceived hardness exhibited a strong correlation with finger displacement of the mirrored, but not hidden, hand. The modulatory effects on perceived hardness diminished when participants touched the pad with both hands asynchronously or with their eyes closed. Moreover, participants experienced ownership of the mirrored hand when they touched the pad with both hands synchronously but not asynchronously. These results indicate that hardness estimates were modulated by observation of the mirrored hand during synchronous touch conditions. The present study demonstrates that, similar to passive touch, active touch is also modulated by visual input

    Bifidobacteria upregulate expression of toll-like receptor negative regulators counteracting enterotoxigenic Escherichia coli mediated inflammation in bovine intestinal epitheliocytes

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    We previously established a bovine intestinal epithelial cell line (BIE cells) and showed that BIE cells are useful in vitro model system for the study of interactions between pathogenic and beneficial microorganisms and bovine intestinal epithelial cells (IECs). In the present study we aimed to select potential immunomodulatory bifidobacteria that may be used to beneficially modulate the inflammatory response in bovine IECs. We also aimed to gain insight in the molecular mechanisms involved in the anti-inflammatory effect of bifidobacteria by evaluating the role of Toll-like receptor (TLR)-2 and TLR negative regulators in the regulation of proinflamatory cytokines production and MAPK, NF-κB and PI3K pathways activation in BIE cells. Five bifidobacteria strains were evaluated in this study and according to their capacity to modulate inflammatory response of BIE cells. Despite the unique effect of each strain, four common points were found when comparing the effect of the high and moderate anti-inflammatory strains: 1) Upregulation of TLR negative regulators and the intensity of that upregulation was related to the different immunomodulatory capacity of each bifidobacteria strain. 2) The balance between MAPK activation and MKP-1 upregulation affected the an- ti-inflammatory effect of bifidobacteria in BIE cells. 3) The inhibition of PI3K pathway was related to the an- ti-inflammatory effect of bifidobacteria. 4) The immunoregulatory effect of bifidobacteria in BIE cells is partially de- pendent on TLR2. This study shows that BIE cells can be used for the selection of immunoregulatory bifidobacteria and for studying the mechanisms involved in the protective activity of immunobiotics against TLR4-induced inflammatory damage. In addition, we have demonstrated that the anti-inflammatory effect of bifidobacteria was achieved by a com- plex interaction of multiple TLRs negative regulators as well as the inhibition/activation of multiple signaling pathways.Fil: Murata, Kozue. Tohoku University. Graduate School of Agricultural Science. Laboratory of Animal Products Chemistry. Food and Feed Immunology Group; Japón;Fil: Villena, Julio Cesar. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Tucumán. Centro de Referencia para Lactobacilos (i); Argentina; Tohoku University. Graduate School of Agricultural Science. Laboratory of Animal Products Chemistry. Food and Feed Immunology Group; Japón;Fil: Tomosada, Yohsuke. Tohoku University. Graduate School of Agricultural Science. Laboratory of Animal Products Chemistry. Food and Feed Immunology Group; Japón;Fil: Risa, Hara. Tohoku University. Graduate School of Agricultural Science. Laboratory of Animal Products Chemistry. Food and Feed Immunology Group; Japón;Fil: Chiba, Eriko. Tohoku University. Graduate School of Agricultural Science. Laboratory of Animal Products Chemistry. Food and Feed Immunology Group; Japón;Fil: Shimazu, Tomoyuki. Tohoku University. Graduate School of Agricultural Science. Laboratory of Animal Breeding and Genetics; Japón;Fil: Aso, Hisashi. Tohoku University. Graduate School of Agricultural Science. Cell Biology Laboratory; Japón;Fil: Suda, Yoshihito. Miyagi University. Department of Food, Agriculture and Environmental Science; Japón;Fil: Iwabuchi, Noriyuki. Morinaga Milk Industry Co. Ltd. Food Science and Technology Institute; Japón;Fil: Xiao, Jin-zhong. Morinaga Milk Industry Co. Ltd. Food Science and Technology Institute; Japón;Fil: Saito, Tadao. Tohoku University. Graduate School of Agricultural Science. Laboratory of Animal Products Chemistry. Food and Feed Immunology Group; Japón;Fil: Kitazawa, Haruki. Tohoku University. Graduate School of Agricultural Science. Laboratory of Animal Products Chemistry. Food and Feed Immunology Group; Japón

    Immunobiotic lactic acid bacteria beneficially regulate immune response triggered by poly(I:C) in porcine intestinal epithelial cells

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    This study analyzed the functional expression of TLR3 in various gastrointestinal tissues from adult swine and shows that TLR3 is expressed preferentially in intestinal epithelial cells (IEC), CD172a+CD11R1high and CD4+ cells from ileal Peyer's patches. We characterized the inflammatory immune response triggered by TLR3 activation in a clonal porcine intestinal epitheliocyte cell line (PIE cells) and in PIE-immune cell co-cultures, and demonstrated that these systems are valuable tools to study in vitro the immune response triggered by TLR3 on IEC and the interaction between IEC and immune cells. In addition, we selected an immunobiotic lactic acid bacteria strain, Lactobacillus casei MEP221106, able to beneficially regulate the anti-viral immune response triggered by poly(I:C) stimulation in PIE cells. Moreover, we deepened our understanding of the possible mechanisms of immunobiotic action by demonstrating that L. casei MEP221106 modulates the interaction between IEC and immune cells during the generation of a TLR3-mediated immune response
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