159 research outputs found

    Prediction of dynamic behavior of workpieces in ultrasonic plastic welding

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    Ultrasonic plastic welding is a technique for joining thermoplastic parts through the use of frictional heat and deformation heat generated at the interface between the workpiece parts by high frequency mechanical vibration. This paper proposes a method for predicting the dynamic behavior of the contact surfaces of the parts at the beginning of the welding. The method is based on finite element dynamic contact analysis. To validate the proposed method, the predictions of dynamic behavior are compared with the measured data and a proper friction coefficient of the interface between the parts is determined. In addition, the dynamic behavior of the contact surfaces are investigated when the horn is vibrated at two different operating frequencies, 15 and 19 kHz. The results show that the dynamic behavior considerably depends on a friction coefficient. Furthermore, the displacements and elastic strains of the contact surfaces at 15 kHz are larger than those at 19 kHz. This seemingly results in the better quality of weld for 15 kHz operating frequency.16th Asia Pacific Vibration Conference 24-26 November, 2015 HUST, Hanoi, Vietna

    Modulation by static magnetism of neuronal activity

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    In neurons, the signal propagation involves both the conduction mediated by local electric currents through voltage-sensitive cation channels in axons and the transmission mediated by the exocytotic release of neurotransmitters from nerve endings into synaptic clefts. A great number of desperate efforts have been dedicated to biochemical, pharmacological and molecular biological studies on the elucidation of mechanisms underlying the neurotransmission at synapses, while relatively little attention has been paid to the comprehensive evaluation of the conduction except for local anesthetics. According to a physical theorem, exposure to magnetism should lead to the generation of a certain mechanical force in neurons with concomitant electric currents in a particular situation. In particular, repetitive transcranial magnetic stimulation is beneficial for the treatment of selected patients suffering from depression, bipolar affective disorder and schizophrenia as a possible alternative to the electroconvulsive therapy for refractory depression. In this review, therefore, we will summarize our recent advances made on the neurochemical and molecular biological elucidation in cultured rat hippocampal neurons toward better understanding by the readers of different disciplines of mechanisms associated with the modulation by magnetism of the neuronal activity in the brain.Biomedical Reviews 2004; 15: 21-35

    Passive Oral Immunization by Egg Yolk Immunoglobulin (IgY) to Vibrio cholerae Effectively Prevents Cholera

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    In an attempt to prepare egg yolk immunoglobulin (IgY) to treat and prevent cholera, hens were immunized by a mixture of heat- or formalin-killed Vibrio cholerae O1 and O139 organisms, or by the recombinant cholera toxin B subunit (CTB). The IgYs were partially purified from egg yolk and orally administered to suckling mice before or after challenge with live O1 or O139 cells. The anti-O1 and O139 IgYs and the mixture of either IgY with anti-CTB IgY significantly protected the occurrence of cholera caused by both O1 and O139 infection. Since large amounts of IgY can be prepared very easily and at low cost, this seems to be a useful procedure for preventing and treating cholera

    定常磁場曝露に応答する脳内遺伝子に関する分子薬理学的研究

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    取得学位:博士(薬学),学位授与番号:博甲第721号,学位授与年月日:平成17年3月22

    Collective fusion activity determines neurotropism of an en bloc transmitted enveloped virus

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    麻疹(はしか)ウイルスが「協力」して脳炎を引き起こす仕組みを解明 --新規治療薬の開発やウイルス共通の進化メカニズム解明に期待--. 京都大学プレスリリース. 2023-01-30.Measles virus (MeV), which is usually non-neurotropic, sometimes persists in the brain and causes subacute sclerosing panencephalitis (SSPE) several years after acute infection, serving as a model for persistent viral infections. The persisting MeVs have hyperfusogenic mutant fusion (F) proteins that likely enable cell-cell fusion at synapses and "en bloc transmission" between neurons. We here show that during persistence, F protein fusogenicity is generally enhanced by cumulative mutations, yet mutations paradoxically reducing the fusogenicity may be selected alongside the wild-type (non-neurotropic) MeV genome. A mutant F protein having SSPE-derived substitutions exhibits lower fusogenicity than the hyperfusogenic F protein containing some of those substitutions, but by the wild-type F protein coexpression, the fusogenicity of the former F protein is enhanced, while that of the latter is nearly abolished. These findings advance the understanding of the long-term process of MeV neuropathogenicity and provide critical insight into the genotype-phenotype relationships of en bloc transmitted viruses

    Functional expression of 5-HT2A receptor in osteoblastic MC3T3-E1 cells.

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    In the previous study, we reported the gene expression for proteins related to the function of 5-hydroxytryptamine (5-HT, serotonin) and elucidated the expression patterns of 5-HT(2) receptor subtypes in mouse osteoblasts. In the present study, we evaluated the possible involvement of 5-HT receptor subtypes and its inactivation system in MC3T3-E1 cells, an osteoblast cell line. DOI, a 5-HT(2A) and 5-HT(2C) receptor selective agonist, as well as 5-HT concentration-dependently increased proliferative activities of MC3T3-E1 cells in their premature period. This effect of 5-HT on cell proliferation were inhibited by ketanserin, a 5-HT(2A) receptor specific antagonist. Moreover, both DOI-induced cell proliferation and phosphorylation of ERK1 and 2 proteins were inhibited by PD98059 and U0126, selective inhibitors of MEK in a concentration-dependent manner. Furthermore, treatment with fluoxetine, a 5-HT specific re-uptake inhibitor which inactivate the function of extracellular 5-HT, significantly increased the proliferative activities of MC3T3-E1 cells in a concentration-dependent manner. Our data indicate that 5-HT fill the role for proliferation of osteoblast cells in their premature period. Notably, 5-HT(2A) receptor may be functionally expressed to regulate mechanisms underlying osteoblast cell proliferation, at least in part, through activation of ERK/MAPK pathways in MC3T3-E1 cells.In the previous study, we reported the gene expression for proteins related to the function of 5-hydroxytryptamine (5-HT, serotonin) and elucidated the expression patterns of 5-HT(2) receptor subtypes in mouse osteoblasts. In the present study, we evaluated the possible involvement of 5-HT receptor subtypes and its inactivation system in MC3T3-E1 cells, an osteoblast cell line. DOI, a 5-HT(2A) and 5-HT(2C) receptor selective agonist, as well as 5-HT concentration-dependently increased proliferative activities of MC3T3-E1 cells in their premature period. This effect of 5-HT on cell proliferation were inhibited by ketanserin, a 5-HT(2A) receptor specific antagonist. Moreover, both DOI-induced cell proliferation and phosphorylation of ERK1 and 2 proteins were inhibited by PD98059 and U0126, selective inhibitors of MEK in a concentration-dependent manner. Furthermore, treatment with fluoxetine, a 5-HT specific re-uptake inhibitor which inactivate the function of extracellular 5-HT, significantly increased the proliferative activities of MC3T3-E1 cells in a concentration-dependent manner. Our data indicate that 5-HT fill the role for proliferation of osteoblast cells in their premature period. Notably, 5-HT(2A) receptor may be functionally expressed to regulate mechanisms underlying osteoblast cell proliferation, at least in part, through activation of ERK/MAPK pathways in MC3T3-E1 cells

    Efficient wireless non-radiative mid-range energy transfer

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    We investigate whether, and to what extent, the physical phenomenon of long-lifetime resonant electromagnetic states with localized slowly-evanescent field patterns can be used to transfer energy efficiently over non-negligible distances, even in the presence of extraneous environmental objects. Via detailed theoretical and numerical analyses of typical real-world model-situations and realistic material parameters, we establish that such a non-radiative scheme could indeed be practical for medium-range wireless energy transfer.Comment: 19 pages, 7 figure

    Anti-asialoglycoprotein receptor autoantibodies, detected by a capture-immunoassay, are associated with autoimmune liver diseases.

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    In autoimmune chronic active hepatitis (AIH) and primary biliary cirrhosis (PBC), various autoantibodies including anti-asialoglycoprotein receptor (ASGPR) antibodies have been found in patients' sera. We have previously developed a mouse monoclonal antibody against rat and human ASGPR. In this study, we developed a capture enzyme-linked immunosorbent assay (ELISA) for detection of anti-ASGPR antibodies using this monoclonal antibody and investigated the occurrence of anti-ASGPR antibodies in the sera of patients with various liver diseases. Serum samples were obtained from 123 patients with various liver diseases, including 21 patients with AIH and 40 patients with PBC. In this capture ELISA, the target antigen in the crude rat liver membrane extracts was captured on the ELISA wells by the ASGPR-specific mouse monoclonal antibody. Thus, the cumbersome process of antigen purification was rendered unnecessary. Using this capture ELISA, we detected the anti-ASGPR antibody in 67% of the patients with AIH, in 100% of the patients with PBC, and in 57% of the patients with acute hepatitis type A. However, the anti-ASGPR antibody was rarely detected in patients with other liver diseases such as primary sclerosing cholangitis and obstructive jaundice. Our findings suggest that this capture ELISA would be useful for the detection of anti-ASGPR antibodies in autoimmune liver diseases.</p
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