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Search Results: 1 - 10 of 2106 matches for " Akihiro Ueda "
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Comparison of the Motion Accuracy of a Six Degrees of Freedom Radiotherapy Couch with and without Weights  [PDF]
Akihiro Takemura, Shinichi Ueda, Kimiya Noto, Hironori Kojima, Naoki Isomura
International Journal of Medical Physics,Clinical Engineering and Radiation Oncology (IJMPCERO) , 2013, DOI: 10.4236/ijmpcero.2013.23010
Abstract: In this study, we compared the motion accuracy of six degrees of freedom (6D) couch for precision radiotherapy with or without weights attached to the couch. Two digital cameras were focused on the iso-center of a linear accelerator. Images of a needle which had been fixed to the 6D couch were obtained using the cameras when the couch moved in translation and rotation around each axis. The three-dimensional (3D) coordinates of the needle were calculated from coordinate values in the images. A coordinate error of the needle position relative to the theoretical position was calculated. The errors were obtained with or without a 60 kg weight attached to the 6D couch, and these errors were compared with each other. The mean distance of the 3D error vectors for the weighted test was 0.21 ± 0.11 mm, and >0.16 ± 0.09 mm for the non-weighted test (p < 0.05). However, the difference of two values was 0.06 mm which is smaller than the minimum distance the 6D couch system can correctly move. The variance of 0.16 mm for the Y coordinate errors for the weighted test only was larger than that for the non-weighted test, which was 0.06 mm (p < 0.05). We found that a total weight of 60 kg did not affect the accuracy of the 6D couch clinically. However, the variance of the Y coordinate errors was increased. This might suggest that the addition of this weight increased the uncertainty of the motion of the 6D couch.

Influence of Surface Properties Modified with Fine Shot Peening on Scuffing  [PDF]
Yuya Omiya, Masahiro Fujii, Ryo Ochiai, Koshi Ishimoto, Akihiro Ueda
Journal of Surface Engineered Materials and Advanced Technology (JSEMAT) , 2018, DOI: 10.4236/jsemat.2018.83006
Abstract: Recently, gears of high strength, reliability, and surface-damage-resistant under severe service conditions are required to achieve the weight saving and downsizing of a product. For the high-speed condition in particular, it is important to understand the influence of the surface properties on the scuffing resistance. If the effective surface profile to improve the lubrication property was found, the metal surfaces could be obtained with both surface strength and surface lubricity. Herein, the influence of surface properties modified with fine shot peening, which can form the arbitrary surface profile, on the scuffing resistance in the rolling-sliding contact machine element, was investigated. The scuffing test was performed using a two-cylinder rolling contact test machine. In a specific sliding, a faster roller of 60% and a sliding velocity of 1.75 m/s were utilized. The scuffing test results with shot-peened test rollers and those with non-shot-peened test roller were compared. The influence of the surface roughness of the shot-peened test roller was also discussed. We found that the shot-peened roller had a better scuffing resistance compared with the roller without the shot-peening process.
Connecting Quorum Sensing, c-di-GMP, Pel Polysaccharide, and Biofilm Formation in Pseudomonas aeruginosa through Tyrosine Phosphatase TpbA (PA3885)
Akihiro Ueda,Thomas K. Wood
PLOS Pathogens , 2009, DOI: 10.1371/journal.ppat.1000483
Abstract: With the opportunistic pathogen Pseudomonas aeruginosa, quorum sensing based on homoserine lactones was found to influence biofilm formation. Here we discern a mechanism by which quorum sensing controls biofilm formation by screening 5850 transposon mutants of P. aeruginosa PA14 for altered biofilm formation. This screen identified the PA3885 mutant, which had 147-fold more biofilm than the wild-type strain. Loss of PA3885 decreased swimming, abolished swarming, and increased attachment, although this did not affect production of rhamnolipids. The PA3885 mutant also had a wrinkly colony phenotype, formed pronounced pellicles, had substantially more aggregation, and had 28-fold more exopolysaccharide production. Expression of PA3885 in trans reduced biofilm formation and abolished aggregation. Whole transcriptome analysis showed that loss of PA3885 activated expression of the pel locus, an operon that encodes for the synthesis of extracellular matrix polysaccharide. Genetic screening identified that loss of PelABDEG and the PA1120 protein (which contains a GGDEF-motif) suppressed the phenotypes of the PA3885 mutant, suggesting that the function of the PA3885 protein is to regulate 3,5-cyclic diguanylic acid (c-di-GMP) concentrations as a phosphatase since c-di-GMP enhances biofilm formation by activating PelD, and c-di-GMP inhibits swarming. Loss of PA3885 protein increased cellular c-di-GMP concentrations; hence, PA3885 protein is a negative regulator of c-di-GMP production. Purified PA3885 protein has phosphatase activity against phosphotyrosine peptides and is translocated to the periplasm. Las-mediated quorum sensing positively regulates expression of the PA3885 gene. These results show that the PA3885 protein responds to AHL signals and likely dephosphorylates PA1120, which leads to reduced c-di-GMP production. This inhibits matrix exopolysaccharide formation, which leads to reduced biofilm formation; hence, we provide a mechanism for quorum sensing control of biofilm formation through the pel locus and suggest PA3885 should be named TpbA for tyrosine phosphatase related to biofilm formation and PA1120 should be TpbB.
A high prevalence of extreme hyperferritinemia in acute hepatitis patients
Kazuhiro Kotoh,Akihiro Ueda,Masatake Tanaka
Hepatic Medicine: Evidence and Research , 2009,
Abstract: Kazuhiro Kotoh, Akihiro Ueda, Masatake Tanaka, Masayuki Miyazaki, Masaki Kato, Motoyuki Kohjima, Munechika Enjoji, Makoto Nakamuta, Ryoichi TakayanagiDepartment of Medicine and Bioregulatory Science, Graduate School of Medical Science, Kyushu University, Fukuoda, JapanAbstract: Although the mechanism underlying acute liver failure (ALF) has not been clarified, recent reports indicate overactivation of macrophages is involved in its progression. In diseases in which activated macrophages participate in the progression, elevated serum ferritin concentration counts among the characteristic laboratory findings. If activated macrophages play a key role in the development of ALF, serum ferritin levels might reflect the severity of acute liver injury. To confirm this, we evaluated the correlation between the serum ferritin concentration and other laboratory measurements in patients with acute hepatitis including ALF. One hundred consecutive patients with acute liver injury were enrolled, of whom 19 fulfilled the criteria for ALF. Serum ferritin concentrations correlated with serum alanine transferase activity as a whole. Interestingly, the correlation was strong in patients infected by hepatitis viruses, but weak in others. Although most patients with ALF had high levels of serum ferritin, not a few patients without ALF showed similar results. The serum ferritin level was generally increased in acute hepatitis patients, probably reflecting the degree of macrophage activation in the liver. Overactivation of macrophages appears to be essential, but not sufficient, for the development of ALF. Keywords: acute hepatitis, acute liver failure, ferritin, macrophage
A high prevalence of extreme hyperferritinemia in acute hepatitis patients
Kazuhiro Kotoh, Akihiro Ueda, Masatake Tanaka, et al.
Hepatic Medicine: Evidence and Research , 2009, DOI: http://dx.doi.org/10.2147/HMER.S4393
Abstract: high prevalence of extreme hyperferritinemia in acute hepatitis patients Original Research (6896) Total Article Views Authors: Kazuhiro Kotoh, Akihiro Ueda, Masatake Tanaka, et al. Published Date September 2009 Volume 2009:1 Pages 1 - 7 DOI: http://dx.doi.org/10.2147/HMER.S4393 Kazuhiro Kotoh, Akihiro Ueda, Masatake Tanaka, Masayuki Miyazaki, Masaki Kato, Motoyuki Kohjima, Munechika Enjoji, Makoto Nakamuta, Ryoichi Takayanagi Department of Medicine and Bioregulatory Science, Graduate School of Medical Science, Kyushu University, Fukuoda, Japan Abstract: Although the mechanism underlying acute liver failure (ALF) has not been clarified, recent reports indicate overactivation of macrophages is involved in its progression. In diseases in which activated macrophages participate in the progression, elevated serum ferritin concentration counts among the characteristic laboratory findings. If activated macrophages play a key role in the development of ALF, serum ferritin levels might reflect the severity of acute liver injury. To confirm this, we evaluated the correlation between the serum ferritin concentration and other laboratory measurements in patients with acute hepatitis including ALF. One hundred consecutive patients with acute liver injury were enrolled, of whom 19 fulfilled the criteria for ALF. Serum ferritin concentrations correlated with serum alanine transferase activity as a whole. Interestingly, the correlation was strong in patients infected by hepatitis viruses, but weak in others. Although most patients with ALF had high levels of serum ferritin, not a few patients without ALF showed similar results. The serum ferritin level was generally increased in acute hepatitis patients, probably reflecting the degree of macrophage activation in the liver. Overactivation of macrophages appears to be essential, but not sufficient, for the development of ALF.
Acute liver failure caused by drug-induced hypersensitivity syndrome associated with hyperferritinemia
Masayuki Miyazaki,Masatake Tanaka,Akihiro Ueda,Tsuyoshi Yoshimoto
World Journal of Gastroenterology , 2011, DOI: 10.3748/wjg.v17.i44.4928
Abstract: Drug-induced hypersensitivity syndrome (DIHS) is a severe reaction usually characterized by fever, rash, and multiorgan failure, occurring 2-6 wk after drug introduction. It is an immune-mediated reaction involving macrophage and T-lymphocyte activation and cytokine release. A 54-year-old woman was diagnosed with rheumatic arthritis and initiated salazosulfapyridine by mouth. About 10 d later, she had a high fever, skin rash and liver dysfunction. She was admitted to hospital and diagnosed with a drug eruption. She was treated with oral prednisolone 30 mg/d; however, she developed high fever again and her blood tests showed acute liver failure and cytopenia associated with hyperferritinemia. She was diagnosed with acute liver failure and hemophagocytosis caused by DIHS. She was transferred to the Department of Medicine and Bioregulatory Science, Kyushu University, where she was treated with arterial steroid injection therapy. Following this treatment, her liver function improved and serum ferritin immediately decreased. We hypothesized that an immune-mediated reaction in DIHS may have generated over-activation of macrophages and T-lymphocytes, followed by a cytokine storm that affected various organs. The measurement of serum ferritin might be a useful marker of the severity of DIHS.
A New Cluster of Galaxies towards the Galactic Bulge, Suzaku J1759-3450
Hideyuki Mori,Yoshitomo Maeda,Akihiro Furuzawa,Yoshito Haba,Yoshihiro Ueda
Physics , 2013, DOI: 10.1093/pasj/65.5.102
Abstract: We observed an extended X-ray source designated as Suzaku J1759-3450 with the Suzaku and Chandra observations towards 1RXS J175911.0-344921, which is an unidentified X-ray source listed in the ROSAT Bright Source Catalogue. A conspicuous emission line at 6 keV was also found in the Suzaku J1759-3450 spectrum. Assuming the emission line to be K emission from He-like Fe ions, we inferred Suzaku J1759-3450 to be an extragalactic object located at z = 0.13. The radial profile of the surface brightness in the 0.5-10 keV band was explained well with an isothermal beta-model of r_c = 1.61' and beta = 0.78. The X-ray spectrum was well reproduced by an optically-thin thermal plasma with the electron temperature of kT_e = 5.3 keV attenuated by the photoelectric absorption of N_H = 2.3 x 10^21 cm^-2. The bolometric X-ray luminosity of L_X (r < r_500) = 4.3 x 10^44 erg s^-1 is consistent with that expected from the L_X-T relation of clusters of galaxies. In terms of the spatial extent, the X-ray spectrum, and the bolometric luminosity of the X-ray emitting gas, we concluded that Suzaku J1759-3450 is a new cluster of galaxies.
Chromosomal Studies of Masculinized Hybrids in Bitterlings (Teleostei: Cypriniformes: Acheilognathinae)  [PDF]
Takayoshi Ueda, Yukie Ueda
Natural Resources (NR) , 2016, DOI: 10.4236/nr.2016.76028
Abstract: The chromosome analysis of the masculinized hybrid between female Tanakia limbata and male T. signifer in bitterlings (Acheilognathinae) was done. It was presumed that they had intermediate karyotype between the parents, and formed sperms with heteroploidy resulting from the incomplete pairing of homologous chromosomes in meiosis. Due to the abundance of species and the ease of artificial fertilization, the study of the factor of the hybrid sterility in bitterlings would lead to the clarification of the mechanism about species differentiation and karyotype differentiation, and also to developing a new variety.
Chromosomal Studies of the Hybrid between Female Rhodeus ocellatus ocellatus and Male Rhodeus atremius fangi in Bitterlings (Teleostei: Cypriniformes: Acheilognathinae)  [PDF]
Takayoshi Ueda, Yukie Ueda
Natural Resources (NR) , 2018, DOI: 10.4236/nr.2018.91002
Abstract:
The chromosome analysis of the masculinized hybrid between female Rhodeus ocellatus ocellatus and male R. atremius fangi in bitterlings (Acheilognathinae) was done. It was presumed that they had intermediate karyotype between the parents, and formed sperms with heteroploidy resulting from the incomplete pairing of homologous chromosomes in meiosis. Due to the abundance of species and the ease of artificial fertilization, the study of the factor of the hybrid sterility in bitterlings would lead to the clarification of the mechanism about species differentiation and karyotype differentiation, and also develop a new variety. And also, it would also be important to make the hybrid various natures clear in environmental preservation.
Auricular Acupunctures Are Effective for the Prevention of Postoperative Agitation in Old Patients
Young-Chang P. Arai,Akihiro Ito,Soki Hibino,Sinnosuke Niwa,Wasa Ueda
Evidence-Based Complementary and Alternative Medicine , 2010, DOI: 10.1093/ecam/nep172
Abstract: Postoperative cognitive problems and delirium are not uncommon in the elderly. We reported four cases in which auricular acupunctures on the ‘Shenmen’ and ‘Point Zero’ points successfully managed postoperative problematic behaviors of the three patients with dementia and the one patient postoperatively demonstrating an agitated behavior.
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