227 research outputs found

    Design of teleoperation system with a force-reflecting real-time simulator

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    We developed a force-reflecting teleoperation system that uses a real-time graphic simulator. This system eliminates the effects of communication time delays in remote robot manipulation. The simulator provides the operator with predictive display and feedback of computed contact forces through a six-degree of freedom (6-DOF) master arm on a real-time basis. With this system, peg-in-hole tasks involving round-trip communication time delays of up to a few seconds were performed at three support levels: a real image alone, a predictive display with a real image, and a real-time graphic simulator with computed-contact-force reflection and a predictive display. The experimental results indicate the best teleoperation efficiency was achieved by using the force-reflecting simulator with two images. The shortest work time, lowest sensor maximum, and a 100 percent success rate were obtained. These results demonstrate the effectiveness of simulated-force-reflecting teleoperation efficiency

    Growth of R-123 Phase Single Crystal Whiskers

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    Single-crystal whiskers of R1Ba2Cu3Ox (R-123, R= La, Nd, Sm, Eu, Gd, Dy, Ho, Er, Tm, Yb and Lu) phase have been successfully grown by the Te- and Ca-doping method. The whiskers were grown from precursor pellets at just below their partial melting (peritectic) temperatures. The nominal composition of the R-123 whiskers is R1+uBa2+vCawCu3Ox (u+v+w=0, w>0) with R and/or Ba sites being substituted by Ca. However, the amount of Te was less than the analytical limit. The critical temperatures of the R-123 whiskers were around 80 K, and among these whiskers those with larger R ionic radii such as Dy, Gd, Eu and Sm require post-annealing in an oxygen atmosphere.Comment: R1Ba2Cu3O7-d, whisker, R ionic radius, crystal growth, Ca including R-123 phase, critical temperature, composition. To be published in Jpn. J. Appl. Phy

    Comparison of prevalence of metabolic syndrome in hospital and community-based Japanese patients with schizophrenia

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    <p>Abstract</p> <p>Background</p> <p>Lifestyle factors, such as an unbalanced diet and lack of physical activity, may affect the prevalence of metabolic syndrome (MetS) in schizophrenic patients. The aim of this study was to compare the MetS prevalence between inpatients and outpatients among schizophrenic population in Japan.</p> <p>Methods</p> <p>We recruited inpatients (n = 759) and outpatients (n = 427) with a <it>Diagnostic and Statistical Manual of Mental Disorders</it>, fourth edition (DSM-IV) diagnosis of schizophrenia or schizoaffective disorder from 7 psychiatric hospitals using a cross-sectional design. MetS prevalence was assessed using three different definitions, including the adapted National Cholesterol Education Program Adult Treatment Panel (ATP III-A).</p> <p>Results</p> <p>The overall MetS prevalences based on the ATP III-A definition were 15.8% in inpatients and 48.1% in outpatients. In a logistic regression model with age and body mass index as covariates, being a schizophrenic outpatient, compared to being a schizophrenic inpatient, was a significant independent factor (odds ratio = 3.66 for males, 2.48 for females) in the development of MetS under the ATP III-A definition. The difference in MetS prevalence between inpatients and outpatients was observed for all age groups in males and for females over 40 years of age.</p> <p>Conclusions</p> <p>Outpatients with schizophrenia or schizoaffective disorder in Japan had a high prevalence of MetS compared to inpatients. MetS in schizophrenic outpatients should be carefully monitored to minimize the risks. A change of lifestyle might improve MetS in schizophrenic patients.</p

    HLA-A*0201-restricted CTL epitope of a novel osteosarcoma antigen, papillomavirus binding factor

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    <p>Abstract</p> <p>Background</p> <p>To develop peptide-based immunotherapy for osteosarcoma, we previously identified papillomavirus binding factor (PBF) as a CTL-defined osteosarcoma antigen in the context of HLA-B55. However, clinical application of PBF-based immunotherapy requires identification of naturally presented CTL epitopes in osteosarcoma cells in the context of more common HLA molecules such as HLA-A2.</p> <p>Methods</p> <p>Ten peptides with the HLA-A*0201 binding motif were synthesized from the amino acid sequence of PBF according to the BIMAS score and screened with an HLA class I stabilization assay. The frequency of CTLs recognizing the selected PBF-derived peptide was determined in peripheral blood of five HLA-A*0201<sup>+ </sup>patients with osteosarcoma using limiting dilution (LD)/mixed lymphocyte peptide culture (MLPC) followed by tetramer-based frequency analysis. Attempts were made to establish PBF-specific CTL clones from the tetramer-positive CTL pool by a combination of limiting dilution and single-cell sorting. The cytotoxicity of CTLs was assessed by <sup>51</sup>Cr release assay.</p> <p>Results</p> <p>Peptide PBF A2.2 showed the highest affinity to HLA-A*0201. CD8+ T cells reacting with the PBF A2.2 peptide were detected in three of five patients at frequencies from 2 × 10<sup>-7 </sup>to 5 × 10<sup>-6</sup>. A tetramer-positive PBF A2.2-specific CTL line, 5A9, specifically lysed allogeneic osteosarcoma cell lines that expressed both PBF and either HLA-A*0201 or HLA-A*0206, autologous tumor cells, and T2 pulsed with PBF A2.2. Five of 12 tetramer-positive CTL clones also lysed allogeneic osteosarcoma cell lines expressing both PBF and either HLA-A*0201 or HLA-A*0206 and T2 pulsed with PBF A2.2.</p> <p>Conclusion</p> <p>These findings indicate that PBF A2.2 serves as a CTL epitope on osteosarcoma cells in the context of HLA-A*0201, and potentially, HLA-A*0206. This extends the availability of PBF-derived therapeutic peptide vaccines for patients with osteosarcoma.</p

    シゼン VLF ホウシャ キョウド ト ギンガ ザツオン デンパ キュウシュウ CNA ノ ソウカン カンケイ ヲ モチイタ カブ デンリソウ デンシ ミツド ノ スイテイ

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    本研究では,地上で観測されるVLFホイスラモード波(昼間に観測されるコーラス)の電離層減衰率とCNAを用いた新しい下部電離層電子密度のリモートセンシング技術を提案する.そのために,さまざまな電子密度モデルに対する両者の関係を理論的に評価している.評価の手法は,full-wave解析を用いてVLFホイスラモード波の下部電離層減衰率とCNAを理論計算している.計算結果は観測結果と同様にCNAとVLF波動の負相関を示し,さらに,増大した電子密度モデルの最大電子密度高度が下がるにつれ,CNA-VLF負相関の傾きが増大する関係を示した.つまり,観測されたCNA-VLF負相関の傾きが,降下粒子に伴う下部電離層を増大させる電子密度高度を推定する情報源に成りえるということが分かった.これは,夜間のみに生じるTrimpi現象と共に,昼間の降下粒子検出に対する新しい下部電離層電子密度推定手法となるであろう.In this study, we suggest a new remote sensing technique for enhanced electron density in the lower ionosphere by using the correlation between VLF whistler mode waves (daytime chorus emissions) and CNA, both observed on the ground. The ionospheric attenuations for VLF whistler mode and HF waves (as a CNA value) are calculated by using full-wave analysis to evaluate their correlations for various ionospheric electron density profiles enhanced by precipitating electrons. The calculation results show negative correlations between CNA and VLF whistler mode waves in accordance with the observation results. Then, the gradient of the negative correlation becomes larger with decreasing altitude of maximum electron density. Thus, we found that the correlation provides information on the vertical profile of the enhanced electron density in the lower ionosphere caused by electron precipitation. This allows the study of electron precipitation in the daytime, in addition to Trimpi events at nighttime

    MDM2 is a novel E3 ligase for HIV-1 Vif

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    The human immunodeficiency virus type 1 (HIV-1) Vif plays a crucial role in the viral life cycle by antagonizing a host restriction factor APOBEC3G (A3G). Vif interacts with A3G and induces its polyubiquitination and subsequent degradation via the formation of active ubiquitin ligase (E3) complex with Cullin5-ElonginB/C. Although Vif itself is also ubiquitinated and degraded rapidly in infected cells, precise roles and mechanisms of Vif ubiquitination are largely unknown. Here we report that MDM2, known as an E3 ligase for p53, is a novel E3 ligase for Vif and induces polyubiquitination and degradation of Vif. We also show the mechanisms by which MDM2 only targets Vif, but not A3G that binds to Vif. MDM2 reduces cellular Vif levels and reversely increases A3G levels, because the interaction between MDM2 and Vif precludes A3G from binding to Vif. Furthermore, we demonstrate that MDM2 negatively regulates HIV-1 replication in non-permissive target cells through Vif degradation. These data suggest that MDM2 is a regulator of HIV-1 replication and might be a novel therapeutic target for anti-HIV-1 drug

    Delivering the world’s most intense muon beam

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    A new muon beam line, the muon science innovative channel, was set up at the Research Center for Nuclear Physics, Osaka University, in Osaka, Japan, using the 392 MeV proton beam impinging on a target. The production of an intense muon beam relies on the efficient capture of pions, which subsequently decay to muons, using a novel superconducting solenoid magnet system. After the pion-capture solenoid, the first 36° of the curved muon transport line was commissioned and the muon flux was measured. In order to detect muons, a target of either copper or magnesium was placed to stop muons at the end of the muon beam line. Two stations of plastic scintillators located upstream and downstream from the muon target were used to reconstruct the decay spectrum of muons. In a complementary method to detect negatively charged muons, the x-ray spectrum yielded by muonic atoms in the target was measured in a germanium detector. Measurements, at a proton beam current of 6 pA, yielded (10.4±2.7)×10^{5}  muons per watt of proton beam power (μ^{+} and μ^{-}), far in excess of other facilities. At full beam power (400 W), this implies a rate of muons of (4.2±1.1)×10^{8}  muons s^{−1}, among the highest in the world. The number of μ^{-} measured was about a factor of 10 lower, again by far the most efficient muon beam produced. The setup is a prototype for future experiments requiring a high-intensity muon beam, such as a muon collider or neutrino factory, or the search for rare muon decays which would be a signature for phenomena beyond the Standard Model of particle physics. Such a muon beam can also be used in other branches of physics, nuclear and condensed matter, as well as other areas of scientific research

    Development of a novel artificial intelligence algorithm to detect pulmonary nodules on chest radiography

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    Background: In this study, we aimed to develop a novel artificial intelligence (AI) algorithm to support pulmonary nodule detection, which will enable physicians to efficiently interpret chest radiographs for lung cancer diagnosis. Methods: We analyzed chest X-ray images obtained from a health examination center in Fukushima and the National Institutes of Health (NIH) Chest X-ray 14 dataset. We categorized these data into two types: type A included both Fukushima and NIH datasets, and type B included only the Fukushima dataset. We also demonstrated pulmonary nodules in the form of a heatmap display on each chest radiograph and calculated the positive probability score as an index value. Results: Our novel AI algorithms had a receiver operating characteristic (ROC) area under the curve (AUC) of 0.74, a sensitivity of 0.75, and a specificity of 0.60 for the type A dataset. For the type B dataset, the respective values were 0.79, 0.72, and 0.74. The algorithms in both the type A and B datasets were superior to the accuracy of radiologists and similar to previous studies. Conclusions: The proprietary AI algorithms had a similar accuracy for interpreting chest radiographs when compared with previous studies and radiologists. Especially, we could train a high quality AI algorithm, even with our small type B data set. However, further studies are needed to improve and further validate the accuracy of our AI algorithm
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