1,539 results on '"K. Tsubota"'
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2. The temporal brightening of Uranus’ northern polar hood from HST/WFC3 & HST/STIS observations
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Arjuna James, Patrick G.J. Irwin, Jack Dobinson, Michael H. Wong, Troy K. Tsubota, Amy Simon, Leigh N Fletcher, Michael Thomas Roman, Nicholas Teanby, Daniel Toledo, and Glenn S Orton
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Hubble Space Telescope Wide-Field Camera 3 (HST/WFC3) observations spanning 2015 to 2021 confirm a brightening of Uranus’ north polar hood feature with time. The vertical aerosol model of Irwin et al. (2023) (IRW23), consisting of a deep haze layer based at ~5 bar, a 1 - 2 bar haze layer, and an extended haze rising up from the 1 - 2 bar layer, was applied to retrievals on HST Space Telescope Imaging Spectrograph (HST/STIS) observations (Sromovsky et al., 2014, 2019} revealing a reduction in cloud-top CH4 by an average of 0.19 {plus minus} 0.03% between 40 - 80{degree sign}N between 2012 and 2015. A combination of latitudinal retrievals on the HST/WFC3 & HST/STIS datasets, again employing the IRW23 model, reveal a temporal thickening of the 1 - 2 bar haze layer to be the main cause of the polar hood brightening, finding an average increase of 1.09 {plus minus} 0.08 at 0.8 μm north of ~45{degree sign}N, concurrent with a decrease in the imaginary refractive index spectrum of the 1 - 2 bar haze layer north of ~40{degree sign}N and longwards of ~0.7 μm, and between 60{degree sign}N and 80{degree sign}N at ~0.5 μm. Small contributions to the brightening were found from a thickening of the deep aerosol layer, with an average increase in integrated opacity of 0.6 {plus minus} 0.1 north of 45{degree sign}N between 2012 and 2015, and from the aforementioned decrease in cloud-top CH4 abundance. Our results are consistent with the slowing of a meridional circulation, exhibiting strong subsidence at the poles.
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- 2023
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3. China–Kyrgyzstan Railway Meets IDE–GSM
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S. Kumagai, I. Isono, S. Keola, K. Hayakawa, T. Gokan, and K. Tsubota
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- 2019
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4. An Intelligent Compiler Subsystem for a Silicon Compiler.
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D. L. Johannsen, S. K. Tsubota, and Kenneth S. McElvain
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- 1987
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5. MilliarcsecondN‐Band Observations of the Nova RS Ophiuchi: First Science with the Keck Interferometer Nuller
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R. Smythe, T. Panteleeva, Richard K. Barry, W. A. Traub, Marc J. Kuchner, Rachel Akeson, Dean L. Palmer, Matthew A. Greenhouse, W. Dahl, C. Felizardo, J. L. Sokoloski, John P. Wisniewski, A. J. Booth, M. J. Creech-Eakman, H. Brandenburg, K. Tsubota, Christopher D. Koresko, Eugene Serabyn, M. Hrynevych, C. Tyau, Mark G. Swain, B. Mennesson, P. Wizinowich, Rafael Millan-Gabet, G. Vasisht, J. Garcia, J. Herstein, E. Hovland, M. Mark Colavita, M. Shao, Julien Woillez, K. Summers, J. Gathright, J. Bell, S. Ragland, E. Appleby, David Morrison, R. Ligon, E. Wetherell, W. C. Danchi, and Samuel L. Crawford
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Physics ,Red giant ,Astrophysics::High Energy Astrophysical Phenomena ,Astrophysics (astro-ph) ,FOS: Physical sciences ,White dwarf ,Astronomy and Astrophysics ,Astrophysics::Cosmology and Extragalactic Astrophysics ,Astrophysics ,Stars ,Space and Planetary Science ,Planet ,Angular diameter ,RS Ophiuchi ,Astrophysics::Solar and Stellar Astrophysics ,Astrophysics::Earth and Planetary Astrophysics ,Emission spectrum ,Astrophysics::Galaxy Astrophysics ,Nuller - Abstract
We report observations of the nova RS Ophiuchi (RS Oph) using the Keck Interferometer Nuller (KIN), approximately 3.8 days following the most recent outburst that occurred on 2006 February 12. These observations represent the first scientific results from the KIN, which operates in N-band from 8 to 12.5 microns in a nulling mode. By fitting the unique KIN data, we have obtained an angular size of the mid-infrared continuum of 6.2, 4.0, or 5.4 mas for a disk profile, gaussian profile (FWHM), and shell profile respectively. The data show evidence of enhanced neutral atomic hydrogen emission and atomic metals including silicon located in the inner spatial regime near the white dwarf (WD) relative to the outer regime. There are also nebular emission lines and evidence of hot silicate dust in the outer spatial region, centered at ! 17 AU from the WD, that are not found in the inner regime. Our evidence suggests that these features have been excited by the nova flash in the outer spatial regime before the blast wave reached these regions. These identifications support a model in which the dust appears to be present between outbursts and is not created during the outburst event. We further discuss the present results in terms of a unifying model of the system that includes an increase in density in the plane of the orbit of the two stars created by a spiral shock wave caused by the motion of the stars through the cool wind of the red giant star. These data show the power and potential of the nulling technique which has been developed for the detection of Earth-like planets around nearby stars for the Terrestrial Planet Finder Mission and Darwin missions., 41 pages, 10 figures
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- 2008
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6. Long Baseline Nulling Interferometry with the Keck Telescopes: a Progress Report
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T. Panteleeva, C. Tyau, K. Tsubota, J. Herstein, Bertrand Mennesson, Andy C. Rudeen, Michelle Creech-Eakman, Rafael Millan-Gabet, Eugene Serabyn, J. Gathright, Erik M. Johansson, Mark R. Swain, S. Crawford, Gautam Vasisht, Christopher D. Koresko, T. Saloga, M. Hrynevych, E. Hovland, A. J. Booth, M. Shao, Rachel Akeson, L. Reder, Peter Wizinowich, D. Le Mignant, M. Mark Colavita, J. Bell, J. Garcia, E. Appleby, S. Ragland, K. Summers, Dean L. Palmer, R. Smythe, Christopher G. Paine, James L. Fanson, C. Felizardo, Julien Woillez, Christopher R. Neyman, R. Ligon, W. Dahl, and James G. Moore
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Physics ,Astronomical optical interferometry ,business.industry ,media_common.quotation_subject ,Astrophysics::Instrumentation and Methods for Astrophysics ,Astronomy ,Astronomy and Astrophysics ,Astrophysics::Cosmology and Extragalactic Astrophysics ,Terrestrial Planet Finder ,Interferometry ,Optical path ,Optics ,Space and Planetary Science ,Sky ,Astronomical interferometer ,Terrestrial planet ,Astrophysics::Earth and Planetary Astrophysics ,business ,Astrophysics::Galaxy Astrophysics ,Nuller ,media_common - Abstract
The Keck Interferometer Nuller (KIN) is one of the major scientific and technical precursors to the Terrestrial Planet Finder Interferometer (TPF-I) mission. KIN's primary objective is to measure the level of exo-zodiacal mid-infrared emission around nearby main sequence stars, which requires deep broad-band nulling of astronomical sources of a few Janskys at 10 microns. A number of new capabilities are needed in order to reach that goal with the Keck telescopes: mid-infrared coherent recombination, interferometric operation in 'split pupil' mode, N-band optical path stabilization using K-band fringe tracking and internal metrology, and eventually, active atmospheric dispersion correction. We report here on the progress made implementing these new functionalities, and discuss the initial levels of extinction achieved on the sky.
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- 2005
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7. Overview of the stability and barrier functions of the granitic geosphere at the Kamaishi Mine: relevance to radioactive waste disposal in Japan
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Kenji Amano, M. Kawamura, Katsuhiro Hama, K. Aoki, Hidekazu Yoshida, K. Ota, T. Semba, and K. Tsubota
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Site selection ,Radioactive waste ,Geology ,engineering.material ,Site analysis ,Geotechnical Engineering and Engineering Geology ,Geotechnics ,Iron ore ,Mining engineering ,Rock mechanics ,engineering ,Fracture (geology) ,Groundwater - Abstract
The Kamaishi in situ studies were carried out in order to provide a technical basis for the studies of the geological disposal of High-level Radioactive Waste (HLW) in Japan. The studies were conducted in drifts located at ca. 300 m and ca. 700 m below the surface in the former Kamaishi iron ore mine, situated in the Kurihashi granodiorite, an early Cretaceous granitic rock (110∼120 Ma) in the Kitakami area, Iwate Prefecture, northeastern Japan. The fractures identified in the Kurihashi granodiorite were mainly formed during the early stages of the cooling process. The mineralogical and dating data suggest that almost no new fractures have been generated since 70∼60 Ma ago. The fractures have high-porosity fracture fillings with relatively high sorption values that imply the fractured granitic rock could have a significant retardation capability for contaminant transport through the granite. Monitoring of hydrological and geochemical conditions of groundwater for 10 years showed that even fractured granitic rock close to the drift is not thoroughly oxidized, and there are only negligible changes of hydrological conditions and groundwater geochemistry due to earthquakes. This information is of considerable importance for the practical design of a HLW repository and to assess any impact of the pre-closure conditions on the post-closure performance of the geological repository. Finally, the results of the study methodology and tools developed help increase confidence in the technical feasibility of geological disposal of HLW in Japan.
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- 2000
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8. First Light Adaptive Optics Images from the Keck II Telescope: A New Era of High Angular Resolution Imagery
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James E. Larkin, K. Ho, K. Tsubota, William Lupton, James M. Brase, C. Shelton, Claire E. Max, Paul J. Stomski, D. S. Acton, Donald T. Gavel, Andrea M. Ghez, Scot S. Olivier, Jong R. An, Kenneth Avicola, J. Gathright, Bruce Macintosh, Peter Wizinowich, and Olivier Lai
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Diffraction ,Physics ,W. M. Keck Observatory ,Resolution (electron density) ,Astronomy and Astrophysics ,Astrophysics ,First light ,law.invention ,Telescope ,Stars ,Space and Planetary Science ,law ,Angular resolution ,Adaptive optics - Abstract
Adaptive optics (AO) is a technology that corrects in real time for the blurring effects of atmospheric turbulence, in principle allowing Earth‐bound telescopes to achieve their diffraction limit and to “see” as clearly as if they were in space. The power of AO using natural guide stars has been amply demonstrated in recent years on telescopes up to 3–4 m in diameter. The next breakthrough in astronomical resolution was expected to occur with the implementation of AO on the new generation of large, 8–10 m diameter telescopes. In this paper we report the initial results from the first of these AO systems, now coming on line on the 10 m diameter Keck II Telescope. The results include the highest angular resolution images ever obtained from a single telescope (0 \documentclass{aastex} \usepackage{amsbsy} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{bm} \usepackage{mathrsfs} \usepackage{pifont} \usepackage{stmaryrd} \usepackage{textcomp} \usepackage{portland,xspace} \usepackage{amsmath,amsx...
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- 2000
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9. Respiratory syncytial virus-induced interleukin-4 production by human conjunctival epithelial cells contributes to allergy: preliminary study
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H, Fujishima, I, Saito, Y, Okamoto, T, Takeuchi, and K, Tsubota
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Adult ,Male ,Adolescent ,Transcription, Genetic ,Enzyme-Linked Immunosorbent Assay ,Epithelial Cells ,HLA-DR Antigens ,Flow Cytometry ,Polymerase Chain Reaction ,Sensory Systems ,Immunoenzyme Techniques ,Cellular and Molecular Neuroscience ,Ophthalmology ,Respiratory Syncytial Virus, Human ,Humans ,RNA, Viral ,Female ,Interleukin-4 ,Conjunctiva ,Cells, Cultured ,Conjunctivitis, Allergic - Abstract
We previously reported allergic conjunctivitis was associated with a local pattern of cytokines and identified respiratory syncytial virus (RSV) in the conjunctival epithelium, in patients with allergic conjunctivitis. We hypothesized that RSV infected the normal conjunctival epithelium and produced interleukin-4 (IL-4), causing an allergic reaction. To determine this event, we studied production of IL-4 by human conjunctival epithelial cells, after infection with RSV.Conjunctival samples were collected with a special brush and were challenged with 5 x 10(6) pfu/ml of live RSV. RSV infection was detected by immunocytochemical study and RT-PCR. HLA-DR antigen was expressed by flow cytometry. IL-4 was assayed by a sandwich ELISA.Immunocytochemical study and RT-PCR showed that RSV infected the conjunctival epithelial cells. HLA-DR was demonstrated in the RSV-infected conjunctival epithelial cells. Average concentrations of IL-4 in culture supernatants in infected cells were 3.8 +/- 1.8, 3.6 +/- 1.1, and 5.4 +/- 1.8 pg/ml at 24, 48, and 72 h, respectively. Levels in non-infected cells were 0.33 +/- 0.0, 0.59 +/- 0.69, and 0.4 +/- 0.22 pg/ml, respectively (p0.001).Findings suggest that the expression of IL-4 is associated with intracellular infection by RSV in conjunctiva. With our former reports, RSV infection in conjunctival epithelial cells can be suggested as one of the possible environmental pathogens of allergic conjunctivitis.
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- 1998
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10. The Keck Interferometer
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Michelle Creech-Eakman, Charles Beichman, R. R. Thompson, B. C. Berkey, A. Tumminello, E. Hovland, Richard L. Johnson, T. Panteleeva, G. Hardy, A. Niessner, James Wallace, W. Dahl, J. Chin, J. Beletic, Eugene Serabyn, G. Eychaner, Andrew F. Boden, A. I. Sargent, Andy C. Rudeen, B. Parvin, R. Kendrick, Mark R. Swain, Dean L. Palmer, James D. Moore, Michael Shao, M. Mark Colavita, D. McBride, Peter Wizinowich, Christopher R. Neyman, E. R. Ligon, Rachel Akeson, H. A. Lewis, Erik M. Johansson, D. Chan, F. Vescelus, Christopher G. Paine, L. Reder, William Lupton, Christopher D. Koresko, Andrew Cooper, Michael Hess, G. Vasisht, C. Felizardo, Richard Cohen, M. Abajian, R. Smythe, Samuel L. Crawford, Jean Garcia-Gathright, T. Saloga, K. Summers, G. T. van Belle, Drew Medeiros, E. Appleby, C. Tyau, P. Kurpis, J. Walker, Rafael Millan-Gabet, J. Gathright, R. Boutell, Craig E. Nance, H. Henderson, K. Tsubota, J. Vause, A. J. Booth, J. Herstein, P. Swanson, Julien Woillez, B. Smith, J. Berlin, M. Papin, E. Wetherell, J. Kelley, D. Le Mignant, D. S. Acton, J. Bell, S. Ragland, David Morrison, U. Wehmeier, Paul J. Stomski, Frederic H. Chaffee, Bertrand Mennesson, J. Chock, M. Hrynevych, and James L. Fanson
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Wavefront ,Astronomical optical interferometry ,business.industry ,Computer science ,Instrumentation ,Detector ,Astronomy and Astrophysics ,Cophasing ,Interferometry ,Optics ,Space and Planetary Science ,Observatory ,business ,Adaptive optics ,Remote sensing - Abstract
The Keck Interferometer (KI) combined the two 10 m W. M. Keck Observatory telescopes on Mauna Kea, Hawaii, as a long-baseline near- and mid-infrared interferometer. Funded by NASA, it operated from 2001 until 2012. KI used adaptive optics on the two Keck telescopes to correct the individual wavefronts, as well as active fringe tracking in all modes for path-length control, including the implementation of cophasing to provide long coherent integration times. KI implemented high sensitivity fringe-visibility measurements at H (1.6 μm), K (2.2 μm), and L (3.8 μm) bands, and nulling measurements at N band (10 μm), which were used to address a broad range of science topics. Supporting these capabilities was an extensive interferometer infrastructure and unique instrumentation, including some additional functionality added as part of the NSF-funded ASTRA program. This paper provides an overview of the instrument architecture and some of the key design and implementation decisions, as well as a description of all of the key elements and their configuration at the end of the project. The objective is to provide a view of KI as an integrated system, and to provide adequate technical detail to assess the implementation. Included is a discussion of the operational aspects of the system, as well as of the achieved system performance. Finally, details on V^2 calibration in the presence of detector nonlinearities as applied in the data pipeline are provided.
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- 2013
11. Immunohistological analysis of tumour growth factor beta 1 expression in normal and inflamed salivary glands
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H Sakurai, K Tsubota, S Katagiri, Y Kizu, J Saito, N Shinozaki, and M Ono
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Adult ,CD4-Positive T-Lymphocytes ,Male ,Pathology ,medicine.medical_specialty ,medicine.medical_treatment ,Epithelium ,Sialadenitis ,Pathology and Forensic Medicine ,Pathogenesis ,stomatognathic system ,Transforming Growth Factor beta ,medicine ,Humans ,Aged ,biology ,Salivary gland ,HLA-DR Antigens ,General Medicine ,Transforming growth factor beta ,Middle Aged ,medicine.disease ,Immunohistochemistry ,Sjogren's Syndrome ,medicine.anatomical_structure ,Cytokine ,Case-Control Studies ,biology.protein ,Leukocyte Common Antigens ,CCL28 ,Female ,Biomarkers ,Research Article - Abstract
AIM: To determine whether transforming growth factor-beta 1 (TGF-beta 1) has a pathogenetic role in disease of the salivary glands. METHODS: An indirect immunohistochemical technique was used to analyse TGF-beta 1 expression in six specimens of normal salivary gland and 23 surgical specimens. RESULTS: TGF-beta 1 was strongly expressed in the ductal epithelial cells of normal salivary gland tissues (six of six cases) and in inflammatory conditions (eight of 11 cases). In contrast, TGF-beta 1 was not detectable in ductal epithelial cells expressing HLA-DR around infiltrating CD4+ CD45RO+ activated T cells, in the salivary gland tissue of patients with Sjögren's syndrome. CONCLUSION: Because TGF-beta 1 has an essential role in the mucosal immunity of salivary glands, abnormal expression of this cytokine must be regarded as a candidate in the pathogenesis of Sjögren's syndrome.
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- 1996
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12. Non-invasive assessment of the donor corneal endothelium using ocular redox fluorometry
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K Tsubota, Ronald A. Laing, Jun Shimazaki, and Kenneth R. Kenyon
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Adult ,Male ,Corneal endothelium ,medicine.medical_specialty ,genetic structures ,Endothelium ,medicine.medical_treatment ,Eye Banks ,Redox ,Fluorophotometry ,Corneal Transplantation ,Cellular and Molecular Neuroscience ,Cornea ,Ophthalmology ,medicine ,Humans ,Corneal transplantation ,Aged ,business.industry ,Endothelium, Corneal ,Histology ,Anatomy ,eye diseases ,Sensory Systems ,Autofluorescence ,medicine.anatomical_structure ,Female ,sense organs ,business ,Oxidation-Reduction ,Research Article - Abstract
AIMS: To investigate the usefulness of ocular redox fluorometry for evaluating donor corneal endothelial viability. METHODS: Corneas from 42 recipients of penetrating keratoplasty and four donor corneas were examined by ocular redox fluorometry. Autofluorescence from reduced pyridine nucleotides (PN) and oxidised flavoproteins (Fp) of the human corneal endothelium were measured non-invasively, and the PN/Fp ratio was used as a tissue metabolic indicator. Specular microscopy and electron microscopy were also performed. RESULTS: Both the quality of specular microscopic image and the PN/Fp ratio were significantly correlated with the degree of corneal endothelial damage determined by histological examination. Corneas with poor specular microscopic image showed significantly decreased PN/Fp ratio compared with corneas with good or fair specular images (p = 0.041 and 0.027, respectively). The PN/Fp ratio increased in corneas with mildly damaged endothelium but decreased in corneas with severely damaged endothelium determined by histological examination. Evaluation of corneal endothelium by combination of specular microscopy and ocular redox fluorometry showed excellent association with that of histopathological examination (p < 0.0001). CONCLUSION: Ocular redox fluorometry is useful for assessing donor corneal endothelial viability. Combination of ocular redox fluorometry and specular microscopy may increase the ability of donor cornea selection.
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- 1996
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13. TCRの解析と自己免疫性疾患 シェーグレン症候群の多臓器病変における浸潤T細胞レセプター解析
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Isao Matsumoto, Katsuhiko Takabayashi, Akemi Sakamoto, Y. Kita, K. Tsubota, H. Namekawa, Itsuo Iwamoto, Takayuki Sumida, and H. Tamura
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Pathology ,medicine.medical_specialty ,business.industry ,Immunology ,T-cell receptor ,Immunology and Allergy ,Medicine ,General Medicine ,Sjogren s ,business - Published
- 1995
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14. Recent progress at the Keck Interferometer
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S. Ragland, R. Akeson, M. Colavita, R. Millan-Gabet, T. Pantaleeva, B. Smith, K. Summers, P. Wizinowich, J. Woillez, E. Appleby, A. Cooper, C. Felizardo, J. Herstein, D. Morrison, K. Tsubota, C. Tyau, Delplancke, Françoise, Rajagopal, Jayadev K., and Malbet, Fabien
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The Keck Interferometer (KI) combines the two 10m diameter Keck telescopes providing milliarcsecond angular resolution. KI has unique observing capabilities such as sensitive K-band V^2, L-band V^2 and N-band nulling modes. The instrument improvements and status of the Keck Interferometer since the 2010 SPIE meeting are summarized. We discuss the current capabilities of the KI, operational improvements, and the science from the KI during the past two years. We will conclude with a brief note on the closure of the KI facility. Details of dual field phase referencing developments and nulling science results are presented elsewhere at this conference.
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- 2012
15. Self-Phase-Referenced Spectro-Interferometry on the Keck Interferometer
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B. C. Berkey, Drew Medeiros, B. Smith, K. Summers, Josh A. Eisner, E. Appleby, T. Panteleeva, D. Morrison, K. Tsubota, John D. Monnier, Peter Wizinowich, M. Mark Colavita, C. Felizardo, E. Wetherell, Rafael Millan-Gabet, J.-U. Pott, Andrew Cooper, M. Hrynevych, Julien Woillez, S. Ragland, M. Abajian, Rachel Akeson, C. Tyau, and J. Herstein
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Time delay and integration ,Physics ,business.industry ,Astronomy and Astrophysics ,Astrophysics ,Astrometry ,ASTRA ,Differential phase ,Interferometry ,Optics ,Space and Planetary Science ,K band ,Spectral resolution ,business ,Image resolution - Abstract
As part of the astrometric and phase-referenced astronomy (ASTRA) project, three new science modes are being developed for the Keck Interferometer that extend the science capabilities of this instrument to include higher spectral resolution, fainter magnitudes, and astrometry. We report on the successful implementation of the first of these science modes, the self-phase-referencing mode, which provides a K-band (λ = 2.2 μm) spectral resolution of R ∼ 1000 on targets as faint as 7.8 mag with spatial resolution as fine as λ/B = 5 mas in the K band, with the 85 m interferometer baseline. This level of spectral resolution would not have been possible without a phase-referencing implementation extending the integration time limit imposed by atmospheric turbulence. For narrow spectral features, we demonstrate a precision of ± 0.01 on the differential V^2(λ), and ± 1.7 mrad on the differential phase Φ(λ), equivalent to a differential astrometry precision of ± 1.45 μas. This new Keck Interferometer instrument is typically used to study the geometry and location of narrow spectral features at high angular resolution, referenced to a continuum. By simultaneously providing spectral and spatial information, the geometry of velocity fields (e.g., rotating disks, inflows, outflows, etc.) larger than 150 km s^(-1) can also be explored.
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- 2012
16. First Keck Interferometer measurements in self-phase referencing mode: spatially resolving circum-stellar line emission of 48 Lib
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Rachel Akeson, James R. Graham, Rafael Millan-Gabet, C. Felizardo, J.-U. Pott, J. Herstein, Julien Woillez, Andrea M. Ghez, E. Appleby, K. Summers, M. Hrynevych, A. Cooper, B. Berkey, K. Tsubota, Sam Ragland, C. Tyau, D. Medeiros, T. Panteleeva, D. Morrison, M. Mark Colavita, Josh A. Eisner, John D. Monnier, B. Smith, P. L. Wizinowich, Lynne A. Hillenbrand, E. Wetherell, Danchi, William C., Delplancke, Françoise, and Rajagopal, Jayadev K.
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Physics ,Be star ,business.industry ,Near-infrared spectroscopy ,Astrophysics::Cosmology and Extragalactic Astrophysics ,Astrophysics ,Interferometry ,Stars ,Optics ,Astronomical interferometer ,Astrophysics::Solar and Stellar Astrophysics ,Hydrogen line ,Astrophysics::Earth and Planetary Astrophysics ,Emission spectrum ,Spectral resolution ,business ,Astrophysics::Galaxy Astrophysics - Abstract
Recently, the Keck interferometer was upgraded to do self-phase-referencing (SPR) assisted K-band spectroscopy at R 2000. This means, combining a spectral resolution of 150 km /s with an angular resolution of 2.7 mas, while maintaininghigh sensitiviy. This SPR mode operates two fringe trackers in parallel, and explores several infrastructural requirementsfor o -axis phase-referencing, as currently being implemented as the KI-ASTRA project. The technology of self-phase-referencing opens the way to reach very high spectral resolution in near-infrared interferometry. We present the scienti ccapabilities oftheKI-SPRmode indetail, attheexample ofobservations ofthe Be-star48 Lib. Several spectrallinesofthecirumstellar disk are resolved. We describe the rst detection of Pfund-lines in an interferometric spectrum of a Be star, inaddition to Br . The di erential phase signal can be used to (i) distinguish circum-stellar line emission from the star, (ii)to directly measure line asymmetries tracing an asymetric gas density distribution, (iii) to reach a di erential, astrometricprecision beyond single-telescope limits su cient for studying the radial disk structure. Our data support the existence ofa radius-dependent disk density perturbation, typically used to explain slow variations of Be-disk hydrogen line pro les.Keywords: stars: emission-line, Be circumstellar matter stars: individual (48 Lib) techniques: interferometric tech-niques: spectroscopic infrared: stars
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- 2010
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17. Keck I laser guide star AO system integration
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Craig E. Nance, Kenny Grace, Sergey Panteleev, Peter Wizinowich, Drew Medeiros, Steve Doyle, Ed Wetherell, Andrew Cooper, Douglas M. Summers, Jason C. Y. Chin, Chris Neyman, Paul J. Stomski, Thomas Stalcup, and K. Tsubota
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Telescope ,Physics ,W. M. Keck Observatory ,Laser guide star ,Observatory ,law ,Astronomical interferometer ,Astronomy ,First light ,Adaptive optics ,Laser ,law.invention - Abstract
With the much anticipated delivery of the Lockheed Martin Coherent Technology Quasi-CW laser, the W. M. Keck Observatory was able to complete the installation and integration of the Laser Guide Star Adaptive Optics System on the Keck I telescope. The Keck I LGSAO system was developed to provide redundancy for the Keck II system as well as balancing the instrumentation load between the two telescopes and interferometers. With the improved sodium coupling efficiency of the laser and a center launching system, the Keck I laser performance is expected to exceed those on the Keck II system. We present the challenges of integrating the Keck I Laser Guide Star Adaptive Optics System on an operational telescope. We will present issues and performance data related to the primary subsystem components such as the laser itself, the Selex Galileo Avionica launch telescope, the Mitsubishi fiber transport, and the Adaptive Optics System. The paper will also focus on the integration and testing performed at the W. M. Keck headquarters as well as the summit of Mauna Kea. We will present initial first light performance of the Keck I LGSAO System and compare those to the existing Keck II LGSAO System.
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- 2010
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18. W. M. Keck Observatory's next-generation adaptive optics facility
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Al Conrad, S. Thomas, James E. Lyke, Marc Reinig, C. Max, Mark Morris, Alexandre Delacroix, Christopher R. Neyman, J. Bell, Kent Wallace, Thomas Stalcup, Franck Marchis, Drew Medeiros, Donald T. Gavel, Mike Pollard, Randy Bartos, Viswa Velur, D. Morrison, Jason C. Y. Chin, Peter Wizinowich, Renate Kupke, Sergey Panteleev, Erik M. Johansson, Richard Dekany, Sean M. Adkins, E. Wetherell, Elizabeth J. McGrath, K. Tsubota, Antonin Bouchez, Mitchell Troy, Christopher Lockwood, Ellerbroek, Brent L., Hart, Michael, Hubin, Norbert, and Wizinowich, Peter L.
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Physics ,Point spread function ,W. M. Keck Observatory ,Galactic astronomy ,business.industry ,Astrophysics::Instrumentation and Methods for Astrophysics ,Astronomy ,Astrophysics::Cosmology and Extragalactic Astrophysics ,Deformable mirror ,law.invention ,Telescope ,Laser guide star ,Optics ,Observatory ,law ,Astrophysics::Earth and Planetary Astrophysics ,Adaptive optics ,business ,Astrophysics::Galaxy Astrophysics - Abstract
We report on the preliminary design of W.M. Keck Observatory's (WMKO's) next-generation adaptive optics (NGAO) facility. This facility is designed to address key science questions including understanding the formation and evolution of today's galaxies, measuring dark matter in our galaxy and beyond, testing the theory of general relativity in the Galactic Center, understanding the formation of planetary systems around nearby stars, and exploring the origins of our own solar system. The requirements derived from these science questions have resulted in NGAO being designed to have near diffraction-limited performance in the near-IR (K-Strehl ~ 80%) over narrow fields (< 30" diameter) with modest correction down to ~ 700 nm, high sky coverage, improved sensitivity and contrast and improved photometric and astrometric accuracy. The resultant key design features include multi-laser tomography to measure the wavefront and correct for the cone effect, open loop AO-corrected near-IR tip-tilt sensors with MEMS deformable mirrors (DMs) for high sky coverage, a high order MEMS DM for the correction of atmospheric and telescope static errors to support high Strehls and high contrast companion sensitivity, point spread function (PSF) calibration to benefit quantitative astronomy, a cooled science path to reduce thermal background, and a high-efficiency science instrument providing imaging and integral field spectroscopy.
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- 2010
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19. Tear Film Overview
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K. Tsubota and M. Uchino
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medicine.medical_specialty ,Conjunctiva ,Materials science ,biology ,Lactoferrin ,Anatomy ,Ascorbic acid ,eye diseases ,Smooth surface ,chemistry.chemical_compound ,medicine.anatomical_structure ,chemistry ,Cornea ,Ophthalmology ,biology.protein ,medicine ,Uric acid ,sense organs ,Ocular surface - Abstract
The major functions of the tear film are to: (1) maintain a smooth surface for light refraction, (2) lubricate the eyelids, (3) supply the cornea with nutrients by transporting oxygen and a limited number of other nutrients to the avascular cornea, (4) provide white blood cells with access to the cornea and conjunctiva, (5) remove foreign materials from the cornea and conjunctiva, (6) defend the ocular surface from the pathogens via specific and nonspecific antibacterial substances, and (7) protect the ocular surface from free-radical insults with antioxidants such as ascorbic acid, lactoferrin, uric acid, and cysteine.
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- 2010
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20. Keck Interferometer Nuller Data Reduction and On-Sky Performance
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Christopher G. Paine, B. Mennesson, E. R. Ligon, Dean L. Palmer, Sam Crawford, T. Panteleeva, P. Wizinowich, W. Dahl, E. Hovland, K. Tsubota, C. Felizardo, Drew Medeiros, J. Gathright, B. C. Berkey, Julien Woillez, Eugene Serabyn, Christopher D. Koresko, K. Summers, Jean Garcia-Gathright, R. Smythe, M. Hrynevych, C. Tyau, Rafael Millan-Gabet, David Morrison, J. Herstein, S. Ragland, Andrew Cooper, James D. Moore, M. Mark Colavita, Rachel Akeson, Michelle Creech-Eakman, Mark R. Swain, G. Vasisht, A. J. Booth, B. Smith, E. Appleby, and E. Wetherell
- Subjects
Time delay and integration ,Interferometry ,Cophasing ,Narrowband ,Space and Planetary Science ,Computer science ,Astronomy and Astrophysics ,Noise floor ,Nuller ,Remote sensing ,Data reduction ,Communication channel - Abstract
We describe the Keck Interferometer nuller theory of operation, data reduction, and on-sky performance, particularly as it applies to the nuller exozodiacal dust key science program that was carried out between 2008 February and 2009 January. We review the nuller implementation, including the detailed phasor processing involved in implementing the null-peak mode used for science data and the sequencing used for science observing. We then describe the Level 1 reduction to convert the instrument telemetry streams to raw null leakages, and the Level 2 reduction to provide calibrated null leakages. The Level 1 reduction uses conservative, primarily linear processing, implemented consistently for science and calibrator stars. The Level 2 processing is more flexible, and uses diameters for the calibrator stars measured contemporaneously with the interferometer’s K-band cophasing system in order to provide the requisite accuracy. Using the key science data set of 462 total scans, we assess the instrument performance for sensitivity and systematic error. At 2.0 Jy we achieve a photometrically-limited null leakage uncertainty of 0.25% rms per 10 minutes of integration time in our broadband channel. From analysis of the Level 2 reductions, we estimate a systematic noise floor for bright stars of ~0.2% rms null leakage uncertainty per observing cluster in the broadband channel. A similar analysis is performed for the narrowband channels. We also provide additional information needed for science reduction, including details on the instrument beam pattern and the basic astrophysical response of the system, and references to the data reduction and modeling tools.
- Published
- 2009
21. Parallel Computing for Large Scale Stress Analysis of the Shape Adaptation of Bone Microstructures
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T. Yamada, K. Tsubota, and A. Makinouchi
- Published
- 2009
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22. Effect of Platelike Carbides Below the Rolling Surface in a Ball-Washer Thrust Rolling Contact Fatigue Tester
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K Tsubota and A Koyanagi
- Subjects
Washer ,chemistry.chemical_compound ,Materials science ,chemistry ,Martensite ,Metallurgy ,Rolling contact fatigue ,Ball (bearing) ,Oxide ,Thrust ,Carbide - Abstract
It has been observed that platelike carbides form immediately underneath the rolling track of a specimen subjected to rolling contact fatigue tests on the ball-washer thrust type of tester. These carbides are less likely to form when the carbon concentration of the martensite matrix is low and more likely to present themselves when the carbon content is high. Carbon is diffused in the matrix by repeated stresses in the specimen during rolling contacts. This carbon is caught by dislocations between oxide inclusions in fields right beneath the rolling track, where the density of such dislocations is high, and it precipitates as carbide. We have assumed that flakings of the specimen from rolling contact fatigue are attributable to the development and propagation of cracks which originate at the site of the platelike carbides under the rolling track. In order to improve the rolling contact fatigue strength of bearing steel, it is necessary to lower the carbon concentration of the matrix while maintaining the hardness required for the rolling element, and also to reduce and finely disperse oxide inclusions.
- Published
- 2009
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23. Evaluation of Bearing Steels Produced by Powder Metallurgy Process
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K Tsubota
- Subjects
Materials science ,Bearing (mechanical) ,law ,Powder metallurgy ,Metallurgy ,Rolling contact fatigue ,Composite material ,law.invention - Published
- 2009
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24. What Happens to the Fatigue Limit of Bearing Steel Without Nonmetallic Inclusions? : Fatigue Strength of Electron Beam Remelted Super Clean Bearing Steel
- Author
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K Tsubota, Kyozaburo Furumura, Toshiyuki Toriyama, and Y Murakami
- Subjects
Materials science ,Bearing (mechanical) ,law ,Metallurgy ,Cathode ray ,Inclusion (mineral) ,Fatigue limit ,law.invention - Published
- 2009
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25. Quality of High-Carbon Chromium Bearing Steel Produced in the Electric Arc Furnace—Ladle Furnace—RH Vacuum Degassing Vessel—Vertical Continuous Caster
- Author
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K Tsubota and T Uesugi
- Subjects
Materials science ,Bearing (mechanical) ,Metallurgy ,Rolling contact fatigue ,chemistry.chemical_element ,Continuous caster ,Ladle furnace ,High carbon ,law.invention ,Chromium ,chemistry ,law ,Impurity ,Electric arc furnace - Published
- 2009
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26. Keck Interferometer nuller update
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Christopher D. Koresko, M. Mark Colavita, Rachel Akeson, E. Appleby, Christopher G. Paine, E. Wetherell, B. Smith, M. Hrynevych, S. Ragland, C. Tyau, E. R. Ligon, A. Booth, Andrew Cooper, B. C. Berkey, J. Herstein, K. Summers, K. Tsubota, Julien Woillez, B. L. Mennesson, D. Morrison, Rafael Millan-Gabet, C. Felizardo, J. Gathright, Eugene Serabyn, Jean Garcia-Gathright, Peter Wizinowich, T. Panteleeva, Drew Medeiros, Sam Crawford, W. Dahl, Schöller, Markus, Danchi, William C., and Delplancke, Françoise
- Subjects
Physics ,Grism ,Telescope ,Interferometry ,Astronomical optical interferometry ,Observatory ,law ,Astronomical interferometer ,Astrometry ,Astrophysics ,Nuller ,law.invention - Abstract
The Keck Interferometer combines the two 10 m Keck telescopes as a long baseline interferometer, funded by NASA, as a joint development among the Jet Propulsion Laboratory, the W. M. Keck Observatory, and the Michelson Science Center. Since 2004, it has offered an H- and K-band fringe visibility mode through the Keck TAC process. Recently this mode has been upgraded with the addition of a grism for higher spectral resolution. The 10 um nulling mode, for which first nulling data were collected in 2005, completed the bulk of its engineering development in 2007. At the end of 2007, three teams were chosen in response to a nuller key science call to perform a survey of nearby stars for exozodiacal dust. This key science observation program began in Feb. 2008. Under NSF funding, Keck Observatory is leading development of ASTRA, a project to add dual-star capability for high sensitivity observations and dual-star astrometry. We review recent activity at the Keck Interferometer, with an emphasis on the nuller development.
- Published
- 2008
27. Recent progress at the Keck Interferometer: operations and V^2 science
- Author
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Christopher D. Koresko, K. Summers, K. Tsubota, Christopher G. Paine, Andrew Cooper, Sam Crawford, B. Smith, S. Ragland, A. Booth, E. Wetherell, Bertrand Mennesson, Jean Garcia-Gathright, Drew Medeiros, Rafael Millan-Gabet, M. Mark Colavita, R. Ligon, W. Dahl, C. Felizardo, Rachel Akeson, T. Panteleeva, Peter Wizinowich, C. Tyau, E. Appleby, J. Gathright, D. Morrison, B. Parvin, J. Herstein, Eugene Serabyn, B. C. Berkey, Julien Woillez, M. Hrynevych, Schöller, Markus, Danchi, William C., and Delplancke, Françoise
- Subjects
Physics ,Grism ,Telescope ,Interferometry ,Spectrometer ,law ,Visibility (geometry) ,Astronomical interferometer ,Astrophysics ,Astrometry ,Nuller ,law.invention - Abstract
The Keck Interferometer combines the two 10m diameter Ke ck telescopes for near-infrared fringe visibility, and mid-infrared nulling observations. We report on recent progress with an emphasis on new visibility observing capabilities, operations improvements for visibility and nulling, and on recent visibility science. New visibility observing capabilities include a grism spectrometer for higher spectral resolution. Recent improvements include a new AO output dichroic for increased infrared light throughput, and the installation of new wave-front controllers on both Keck telescopes. We also report on recent visibility results in several areas including (1) young stars and their circumstellar disks, (2) pre-main sequence star masses, and (3) Circumstellar environment of ev olved stars. Details on nuller instrument and nuller science results, and the ASTRA phase referencing and astrometry upgrade, are presented in more detail elsewhere in this conference. Keywords: stellar interferometry, visibility measurements, operational efficiency, spectro-interferometry, phase referencing, pre-main sequence binaries
- Published
- 2008
28. Dry eye disease and its implications on visual function
- Author
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M, Dogru, M, Kaido, Y, Matsumoto, and K, Tsubota
- Subjects
Vision Disorders ,Humans ,Dry Eye Syndromes - Published
- 2008
29. Ojo seco y su implicación en la función visual
- Author
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K. Tsubota, M. Kaido, M. Dodru, and Y. Matsumoto
- Subjects
Ophthalmology ,Biology - Published
- 2008
30. Metabolic studies of galactosemic cataract
- Author
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K Tsubota, Hua Xiong, Jing Xiong, and Hong Ming Cheng
- Subjects
Galactosemias ,Male ,medicine.medical_specialty ,Magnetic Resonance Spectroscopy ,Biology ,Cataract ,Nephropathy ,Cellular and Molecular Neuroscience ,chemistry.chemical_compound ,Polyol pathway ,Diabetes mellitus ,Internal medicine ,Lens, Crystalline ,medicine ,Animals ,Aldose reductase ,Osmolar Concentration ,Galactitol ,Galactosemia ,Galactose ,Phosphorus ,Rats, Inbred Strains ,medicine.disease ,Sensory Systems ,Rats ,Ophthalmology ,Endocrinology ,Galactosemic cataract ,chemistry ,Retinopathy - Abstract
Experimental diabetic and galactosemic animal models are widely used to study diabetes-induced complications. Galactose feeding can rapidly produce cataract, retinopathy and nephropathy; it is therefore favored over the diabetic model. Although the common feature for both models is the activation of aldose reductase, there are substantial differences between the two--not only does the rate of cataract progression differ but the metabolic patterns are far more complex than for polyol production alone. We here present the result of a comparison between diabetic and galactosemic lenses and show the differences in phosphorus and aldose metabolism, cell integrity and osmotic environment.
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- 1990
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31. A FLUID-SOLID INTERACTIONS STUDY OF THE PULSE WAVE VELOCITY IN UNIFORM ARTERIES
- Author
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T. FUKUI, Y. IMAI, K. TSUBOTA, T. ISHIKAWA, S. WADA, T. YAMAGUCHI, and K. H. PARKER
- Published
- 2007
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32. Science observations with the Keck Interferometer Nuller
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T. Panteleeva, Christopher D. Koresko, Julien Woillez, Bertrand Mennesson, A. Booth, M. Mark Colavita, R. Ligon, W. A. Traub, Peter Wizinowich, K. Summers, K. Tsubota, J. Garcia, Sam Crawford, J. Gathright, Eugene Serabyn, E. Wetherell, S. Ragland, and M. Hrynevych
- Subjects
Physics ,Brightness ,Interferometry ,Stars ,Observatory ,Astronomical interferometer ,Quantitative Biology::Populations and Evolution ,Astrophysics::Earth and Planetary Astrophysics ,Astrophysics ,Adaptive optics ,Astrophysics::Galaxy Astrophysics ,Nuller ,Exoplanet - Abstract
The Keck Interferometer Nuller (KIN) is now largely in place at the Keck Observatory, and functionalities and performance are increasing with time. The main goal of the KIN is to examine nearby stars for the presence of exozodiacal emission, but other sources of circumstellar emission, such as disks around young stars, and hot exoplanets are also potential targets. To observe with the KIN in nulling mode, knowledge of the intrinsic source spectrum is essential, because of the wide variety of wavelengths involved in the various control loops - the AO system operates at visible wavelengths, the pointing loops use the J-band, the high-speed fringe tracker operates in the K-band, and the nulling observations take place in the N-band. Thus, brightness constraints apply at all of these wavelengths. In addition, source structure plays a role at both K-band and N-band, through the visibility. In this talk, the operation of the KIN is first briefly described, and then the sensitivity and performance of the KIN is summarized, with the aim of presenting an overview of the parameter space accessible to the nuller. Finally, some of the initial observations obtained with the KIN are described.
- Published
- 2006
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33. The dusty AGB star RS CrB: first mid-infrared interferometric observations with the Keck Telescopes
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B. Mennesson, C. Koresko, M. J. Creech-Eakman, E. Serabyn, M. M. Colavita, R. Akeson, E. Appleby, J. Bell, A. Booth, S. Crawford, W. Dahl, J. Fanson, C. Felizardo, J. Garcia, J. Gathright, J. Herstein, E. Hovland, M. Hrynevych, E. Johansson, D. Le Mignant, R. Ligon, R. Millan-Gabet, J. Moore, C. Neyman, D. Palmer, T. Panteleeva, C. Paine, S. Ragland, L. Reder, A. Rudeen, T. Saloga, M. Shao, R. Smythe, K. Summers, M. Swain, K. Tsubota, C. Tyau, G. Vasisht, P. Wizinowich, and J. Woillez
- Subjects
Physics ,Photosphere ,Spectrometer ,Opacity ,Red giant ,Astrophysics (astro-ph) ,FOS: Physical sciences ,Astronomy and Astrophysics ,Astrophysics ,Astrophysics::Cosmology and Extragalactic Astrophysics ,Spectral line ,Wavelength ,Space and Planetary Science ,Asymptotic giant branch ,Astrophysics::Solar and Stellar Astrophysics ,Astrophysics::Earth and Planetary Astrophysics ,Variable star ,Astrophysics::Galaxy Astrophysics - Abstract
We report interferometric observations of the semi-regular variable star RS CrB, a red giant with strong silicate emission features. The data were among the first long baseline mid-infrared stellar fringes obtained between the Keck telescopes, using parts of the new nulling beam combiner. The light was dispersed by a low-resolution spectrometer, allowing simultaneous measurement of the source visibility and intensity spectra from 8 to 12 microns. The interferometric observations allow a non-ambiguous determination of the dust shell spatial scale and relative flux contribution. Using a simple spherically-symmetric model, in which a geometrically thin shell surrounds the stellar photosphere, we find that ~30% to ~70% of the overall mid-infrared flux - depending on the wavelength - originates from 7-8 stellar radii. The derived shell opacity profile shows a broad peak around 11 microns (tau ~ 0.06), characteristic of Mg-rich silicate dust particles., Accepted for publication in ApJ Letters
- Published
- 2005
34. Evaluation results of high-speed modem for EMI reduction automotive use
- Author
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K. Tsubota, T. Takano, Y. Ashizawa, and T. Abe
- Subjects
Engineering ,Frequency-shift keying ,Interference (communication) ,EMI ,business.industry ,Modulation ,Electrical engineering ,Baseband ,Electronic engineering ,business ,Electromagnetic interference ,Noise (radio) ,Data transmission - Abstract
This report describes a high-speed LAN (local area network) for automotive use which eliminates EMI (electromagnetic interference) noise. The automotive LAN is facing two problems due to acceleration of data transfer speed. One is an interference problem in the AM/FM radio receiver. High-speed data transmission makes the baseband frequency higher and higher. EMI energy given out of carrier signal has been several hundred times higher compared to 'command communication'. Another problem is communication interference by induction noise from the ignition and so on. The authors solved the above problems with the development of a 5 MHz FSK (frequency shift keying) modulation circuit. In this paper, the authors explain the technology of the 5 MHz FSK modulation circuit and evaluate results from actual car use.
- Published
- 2005
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- View/download PDF
35. The Keck Interferometer Nuller (KIN): configuration, measurement approach, and first results
- Author
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Christopher G. Paine, Michelle Creech-Eakman, A. Booth, E. Appleby, T. Panteleeva, Christopher D. Koresko, K. Tsubota, Peter Wizinowich, Robert F. Smythe, J. Garcia, M. Hrynevych, E. Wetherell, Julien Woillez, J. Gathright, G. Vasisht, James L. Fanson, Bertrand Mennesson, Jason C. Y. Chin, James D. Moore, M. Mark Colavita, R. Ligon, Dean L. Palmer, Sam Crawford, W. Dahl, Leonard J. Reder, E. Hovland, Eugene Serabyn, T. Saloga, J. Bell, S. Ragland, and C. Tyau
- Subjects
Physics ,Interferometry ,Narrowband ,Mauna kea ,Observatory ,Astronomical interferometer ,Astronomy ,Nuller - Abstract
The Keck Interferometer Nuller (KIN) will be used to examine nearby stellar systems for the presence of circumstellar exozodiacal emission. A successful pre-ship review was held for the KIN in June 2004, after which the KIN was shipped to the Keck Observatory. The integration of the KIN's many sub-systems on the summit of Mauna Kea, and initial on-sky testing of the system, has occupied the better part of the past year. This paper describes the KIN system- level configuration, from both the hardware and control points of view, as well as the current state of integration of the system and the measurement approach to be used. During the most recent on-sky engineering runs, all of the sub- systems necessary to measure a narrowband null were installed and operational, and the full nulling measurement cycle was carried out on stellar targets for the first time.
- Published
- 2005
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36. Observations of DG Tauri with the Keck Interferometer
- Author
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M. Colavita, R. Akeson, P. Wizinowich, M. Shao, S. Acton, J. Beletic, J. Bell, J. Berlin, A. Boden, A. Booth, R. Boutell, F. Chaffee, D. Chan, J. Chock, R. Cohen, S. Crawford, M. Creech-Eakman, G. Eychaner, C. Felizardo, J. Gathright, G. Hardy, H. Henderson, J. Herstein, M. Hess, E. Hovland, M. Hrynevych, R. Johnson, J. Kelley, R. Kendrick, C. Koresko, P. Kurpis, D. Le Mignant, H. Lewis, E. Ligon, W. Lupton, D. McBride, B. Mennesson, R. Millan-Gabet, J. Monnier, J. Moore, C. Nance, C. Neyman, A. Niessner, D. Palmer, L. Reder, A. Rudeen, T. Saloga, A. Sargent, E. Serabyn, R. Smythe, P. Stomski, K. Summers, M. Swain, P. Swanson, R. Thompson, K. Tsubota, A. Tumminello, G. van Belle, G. Vasisht, J. Vause, J. Walker, K. Wallace, and U. Wehmeier
- Subjects
Physics ,Infrared ,Component (thermodynamics) ,Astrophysics (astro-ph) ,Astrophysics::Instrumentation and Methods for Astrophysics ,FOS: Physical sciences ,Astronomy and Astrophysics ,Radius ,Astrophysics ,Astrophysics::Cosmology and Extragalactic Astrophysics ,T Tauri star ,Interferometry ,Space and Planetary Science ,Astrophysics::Solar and Stellar Astrophysics ,Astrophysics::Earth and Planetary Astrophysics ,Astrophysics::Galaxy Astrophysics - Abstract
We present the first science results from the Keck Interferometer, a direct-detection infrared interferometer utilizing the two 10-meter Keck telescopes. The instrument and system components are briefly described. We then present observations of the T Tauri object DG Tau, which is resolved by the interferometer. The resolved component has a radius of 0.12 to 0.24 AU, depending on the assumed stellar and extended component fluxes and the model geometry used. Possible origins and implications of the resolved emission are discussed., 10 pages, 2 figures, to appear in ApJ Letters
- Published
- 2003
37. Dry eye associated with chronic graft-versus-host disease
- Author
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Y, Ogawa, M, Kuwana, K, Yamazaki, Y, Mashima, S, Okamoto, K, Tsubota, Y, Oguchi, and Y, Kawakami
- Subjects
Chronic Disease ,Lacrimal Apparatus ,Graft vs Host Disease ,Humans ,Dry Eye Syndromes - Published
- 2003
38. The effect of acupuncture on the temperature of the ocular surface in conjunctivitis sicca measured by non-contact thermography: preliminary results
- Author
-
Johannes, Nepp, K, Tsubota, E, Goto, J, Schauersberger, G, Schild, K, Jandrasits, C, Abela, and A, Wedrich
- Subjects
Adult ,Male ,Time Factors ,Infrared Rays ,Acupuncture ,Keratoconjunctivitis Sicca ,Middle Aged ,Eye ,Lipid Metabolism ,Body Temperature ,Thermography ,Tears ,Humans ,Female ,Prospective Studies ,Aged - Published
- 2003
39. Overview of the control system for the Keck Interferometer
- Author
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Richard L. Johnson, Robert F. Smythe, Dean L. Palmer, G. Eychaner, Leonard J. Reder, K. Tsubota, William Lupton, E. Hovland, Al Niessner, Andy C. Rudeen, and A. Booth
- Subjects
Java ,Computer science ,business.industry ,Optical engineering ,Interferometry ,Optics ,Common Object Request Broker Architecture ,Real-time Control System ,Control system ,Astronomical interferometer ,User interface ,business ,computer ,Computer hardware ,computer.programming_language - Abstract
The Keck Interferometer links the two 10m Keck Telescopes located atop Mauna Kea in Hawaii. It is the first 10m class, fully AO equipped interferometer to enter operation. Further, it is the first large interferometer designed to be handed over from a design and implementation team to a separate operations team, and be used by astronomers who are not interferometer specialists. As such it offers unique challenges in reducing an extremely complex and powerful system to an apparently simple user interface, and providing a well engineered system that can be maintained by people who did not develop it. This paper gives an overview of the control system that has been implemented for the single baseline operation of the instrument, and indicates how this will be extended to allow control of the future modes of the instrument (nulling, differential phase and astrometry). The control system has several parts. One is for control of "slow" sub-systems, which is based in the EPICS architecture, already ubiquitous at the Keck Observatory. Another, used to control hard real time sub-systems, is based on a new infrastructure developed at JPL, programmed in C++, Java, and using CORBA for communication. This infrastructure has been developed specifically with the problems of interferometric control in mind and is used in JPL's flight testbeds as well as the Keck Interferometer. Finally, a user interface and high level control layer is in development using a variety of tools including UML based modeling in the Rhapsody tool (using C++ and CORBA), Java, and Tcl/Tk for prototyping.© (2002) COPYRIGHT SPIE--The International Society for Optical Engineering. Downloading of the abstract is permitted for personal use only.
- Published
- 2002
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40. Lorentz group Lie algebra map of ultra-relativistic radiating electron
- Author
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H. Kawaguchi, T. Honma, and K. Tsubota
- Subjects
Lorentz group ,Bispinor ,Physics ,Lorentz factor ,symbols.namesake ,Classical mechanics ,Poincaré group ,Current algebra ,symbols ,Four-momentum ,Lorentz covariance ,Velocity-addition formula - Abstract
This paper discusses a precise numerical integrator for ultra-relativistic radiating electron motion. It is firstly shown that the covariant form Lorentz force equation of motion possesses the Lorentz group Lie algebra structure and the Lorentz-Dirac equation of motion as well. After that, a precise numerical integrator for radiating electron is constructed based on the Lie algebra properties. Numerical examples show that this integrator can be effectively used not only for the ultra-relativistic electron motion but also for a non-relativistic electron motions in pure magnetic fields as well.
- Published
- 2002
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- View/download PDF
41. A significant role of stromal fibroblasts in rapidly progressive dry eye in patients with chronic GVHD
- Author
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Y, Ogawa, K, Yamazaki, M, Kuwana, Y, Mashima, Y, Nakamura, S, Ishida, I, Toda, Y, Oguchi, K, Tsubota, S, Okamoto, and Y, Kawakami
- Subjects
Adult ,Male ,B-Lymphocytes ,Leukemia ,Biopsy ,T-Lymphocytes ,Hematopoietic Stem Cell Transplantation ,Lacrimal Apparatus ,Graft vs Host Disease ,Antigens, CD34 ,Fibroblasts ,Middle Aged ,Fibrosis ,Immunoenzyme Techniques ,Chronic Disease ,Disease Progression ,Humans ,Transplantation, Homologous ,Dry Eye Syndromes ,Female - Abstract
To elucidate histopathologic features of the lacrimal gland in chronic graft-versus-host disease (GVHD) after allogeneic hematopoietic stem cell transplantation.Lacrimal gland specimens from five patients who had dry eye as part of the symptoms of chronic GVHD were examined by immunohistochemistry and transmission electron microscopy. Lacrimal gland specimens from five patients with Sjögren's syndrome (SS) were used as control samples.Lymphocytes, predominantly T cells, were found primarily in the periductal areas of the lacrimal gland from patients with chronic GVHD, whereas B cells were the dominant infiltrating cells in the acinar areas of the lacrimal gland from patients with SS. Notable findings in the lacrimal gland from patients with chronic GVHD were marked fibrosis of the glandular interstitium and an increase in the number of CD34(+) stromal fibroblasts. These findings were more prominent in patients with severe dry eye than in those with mild dry eye. Electron microscopic observations of the lacrimal gland from patients with chronic GVHD revealed that stromal fibroblasts were attached to various inflammatory cells, especially T cells, through primitive or rudimentary contacts. In addition, the presence of a well-developed rough endoplasmic reticulum in the fibroblasts and newly synthesized collagen fibrils in the extracellular matrix indicated an active production of extracellular matrix components. Electron micrographs revealed multilayered and thickened basal laminae of blood vessels, ducts, and lobules in the lacrimal gland of patients with chronic GVHD; however, these observations were infrequently observed in the lacrimal glands of patients with SS.The results suggest substantial differences in the lacrimal gland histopathology of patients with chronic GVHD and SS. In addition, it is likely that stromal fibroblasts are actively involved in the pathogenic process of chronic GVHD in the lacrimal gland by producing excessive extracellular matrix components.
- Published
- 2001
42. Improvement of lacrimal function by topical application of CyA in murine models of Sjögren's syndrome
- Author
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K, Tsubota, H, Fujita, K, Tadano, T, Takeuchi, T, Murakami, I, Saito, and Y, Hayashi
- Subjects
Male ,Fas Ligand Protein ,Membrane Glycoproteins ,Administration, Topical ,Lacrimal Apparatus ,Apoptosis ,Mice, Transgenic ,Chemotaxis, Leukocyte ,Disease Models, Animal ,Mice ,Sjogren's Syndrome ,Mice, Inbred NOD ,Tears ,Cyclosporine ,Animals ,Female ,Lymphocytes ,Ophthalmic Solutions ,Fluorescent Antibody Technique, Indirect ,Immunosuppressive Agents - Abstract
The object of this study was to evaluate improvement of lacrimal gland (LG) function after topical cyclosporin A (CyA).Topical CyA (0.01% and 0.1%) was applied to two mouse models of Sjögren's syndrome, the NFS/sld after thymectomy and the nonobese diabetic (NOD) mouse, and the functional integrity of the lacrimal gland was evaluated by measuring basal and stimulated tear secretion and its histologic integrity by examining it for apoptosis and lymphocyte invasion.After treatment with CyA at 0.1% in the NFS/sld mice, tear function increased, and there was a decrease in lymphocyte infiltration of the LG and a decrease in apoptotic figures among the acinar cells. In the NOD mice, tear function also improved, but there was no associated decrease in lymphocyte infiltration. However, the expression of Fas ligand (FasL) in NOD mice by infiltrating lymphocytes was suppressed with 0. 1% CyA eye drops.CyA appears to improve tear secretion in mouse models of Sjögren's syndrome by preventing lymphocyte-induced apoptosis of acinar cells. In one model this was achieved by preventing lymphocyte infiltration and in the other by reducing expression of FasL expression on infiltrating lymphocytes.
- Published
- 2001
43. Initial performance of the Keck AO wavefront controller system
- Author
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Bruce Macintosh, William Lupton, J. Watson, Olivier Lai, Randall L. Hurd, Donald T. Gavel, Jong R. An, Claire E. Max, James M. Brase, Erik M. Johansson, Paul J. Stomski, D. Scott Acton, J. Gathright, J. C. Shelton, Carmen J. Carrano, Scot S. Olivier, Barton V. Beeman, K. Tsubota, Peter Wizinowich, Kenneth E. Waltjen, and Kenneth Avicola
- Subjects
Wavefront ,Physics ,Integration testing ,business.industry ,Bandwidth (signal processing) ,Astrophysics::Instrumentation and Methods for Astrophysics ,Deformable mirror ,law.invention ,Telescope ,Optics ,law ,Adaptive system ,Control system ,business ,Adaptive optics - Abstract
The wavefront controller for the Keck Observatory AO system consists of two separate real-time control loops: a tip-tilt control loop to remove tilt from the incoming wavefront, and a deformable mirror control loop to remove higher-order aberrations. In this paper, we describe these control loops and analyze their performance using diagnostic data acquired during the integration and testing of the AO system on the telescope. Disturbance rejection curves for the controllers are calculated from the experimental data and compared to theory. The residual wavefront errors due to control loop bandwidth are also calculated from the data, and possible improvements to the controller performance are discussed.
- Published
- 2000
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- View/download PDF
44. Mikulicz's disease and Sjögren's syndrome
- Author
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K, Tsubota, H, Fujita, K, Tsuzaka, and T, Takeuchi
- Subjects
Adult ,Male ,Fas Ligand Protein ,Membrane Glycoproteins ,CD3 Complex ,CD8 Antigens ,Lacrimal Apparatus ,Middle Aged ,Mikulicz' Disease ,Immunoenzyme Techniques ,Sjogren's Syndrome ,Tears ,CD4 Antigens ,Humans ,Female ,Lymphocytes ,fas Receptor ,Aged - Abstract
To characterize lacrimal gland function and lymphocyte infiltration in patients with Mikulicz's disease (MD) and Sjögren's syndrome (SS).Four patients with MD and 5 with SS were recruited, on whom were performed Schirmer test I (Schirmer test without anesthesia), Schirmer test with nasal stimulation, and vital staining of the ocular surface. The lacrimal gland was then biopsied and the tissues stained with CD3, CD4, CD8, B220, APO2.7, Fas, and Fas ligand (Fas-L) antibodies.Although regular Schirmer test results in the MD group were less than 10 mm, those with nasal stimulation, 38.1 +/- 3.4 mm, were significantly greater than the SS group. There were minimal ocular surface changes in MD. Morphologic staining with hematoxylin and eosin was identical in both groups, but the acinar cells were stained with APO2.7 only in the SS group. There was strong Fas and Fas-L staining in SS patients but not in those with MD.Lacrimal gland acinar cells in those with MD maintained their function and were not programmed for cell death. The sicca syndrome was not observed in MD patients. Although the pathology is similar for MD and SS, the difference in acinar cell apoptosis and function can explain clinical differences.
- Published
- 2000
45. Telomerase activity and p53 expression in pterygia
- Author
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S, Shimmura, M, Ishioka, K, Hanada, J, Shimazaki, and K, Tsubota
- Subjects
Ultraviolet Rays ,DNA Mutational Analysis ,Enzyme-Linked Immunosorbent Assay ,Epithelial Cells ,Genes, p53 ,Pterygium ,Polymerase Chain Reaction ,Cell Line ,Up-Regulation ,Humans ,Tumor Suppressor Protein p53 ,Conjunctiva ,Telomerase ,Polymorphism, Single-Stranded Conformational - Abstract
To investigate tolomerase activity and p53 expression in pterygial tissue.Pterygia tissue was obtained during excisional surgery fr om 35 eyes of 35 patients, and superior bulbar conjunctival tissue from the same eye was also sampled as control when possible. Fluorescence telomeric repeat amplification protocol was used to measure telomerase activity in whole pterygium samples from 9 cases and in the epithelium and stroma of pterygium from another 10 cases. p53 protein content was measured by enzyme-linked immunosorbent assay (ELISA) in tissues obtained from 7 eyes, as well as in epithelial cell suspensions collected by brush cytology in 8 eyes. Six samples were also analyzed for UV-specific mutations in the p53 gene by the single-strand conformation polymorphism technique and DNA sequencing. A conjunctival epithelial cell line was irradiated with sublethal levels of UV-B to investigate whether telomerase activity can be induced in vitro.In all, 63% of pterygia samples demonstrated telomerase activity, whereas all 10 paired conjunctival control samples were negative (P = 0.05, chi-square test). Of the 10 samples in which telomerase activity was measured separately in the epithelium and stroma of pterygia, 5 samples were positive in the epithelium, only 1 of which had activity in the stroma. Average telomerase activity in positive samples was 18.44 +/- 8.77 U/microg protein, compared with telomerase activity measured in a carcinoma in situ patient (33.73 U/microg), and in an immortalized conjunctival epithelial cell line (50.72 +/- 15.55 U/microg). Telomerase activity was not upregulated in this cell line by UV-B exposure. All 6 pterygia samples tested for p53 mutations did not reveal the UV-specific mutations in exons 5, 6, 7, or 8. No statistical significance was observed in the pterygium or conjunctiva p53 protein levels in epithelial cells collected by brush cytology, while p53 protein level was lower in pterygia when measured in whole tissue samples.Telomerase activity was detected in some pterygia, mostly in the epithelium. Pterygia was not associated with an increase in epithelial p53 protein content measured by ELISA.
- Published
- 2000
46. [Sjögren's syndrome--recent advances in research and treatment]
- Author
-
K, Tsubota
- Subjects
Sjogren's Syndrome ,Humans - Published
- 2000
47. The impact of HLA-A matching in corneal transplantation
- Author
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B, Munkhbat, M, Hagihara, J, Shimazaki, N, Kanai, N, Morita, B, Gansuvd, S, Kato, K, Tsubota, and K, Tsuji
- Subjects
Corneal Transplantation ,HLA-A Antigens ,Transplantation Immunology ,Histocompatibility Testing ,Graft Survival ,Humans ,Alleles ,Retrospective Studies - Abstract
Previously, we have reported the results of our retrospective study on the effect of HLA class II allele matching on the outcome of corneal transplant. Here, we demonstrate our findings of the study for HLA class I allele matching in the same study subjects. Eighty transplant recipients were typed for HLA-A, and 79 transplant recipients were typed for HLA-B alleles, by PCR-SSOP. The association between HLA class I allele matching and 1-year rejection-free graft survival was evaluated. When a total of 79 transplant recipients were subdivided into groups with matching (one to four alleles matched) and without matching (no allele matched) for HLA class I (HLA-A and -B), a significantly higher rate of 1-year rejection-free graft survival was detected in transplant recipients with matching, compared with those without matching (p=0.0258). We have found that matching for at least one HLA class I allele was more beneficial especially in high-risk transplant recipients (p=0.0076). Also, an analysis of matching for each locus separately, detected that, HLA-A matching was significantly associated with a higher rate of 1-year rejection-free graft survival. Transplant recipients with HLA-A matching (one or two-alleles matched) had significantly higher rejection-free graft survival compared with those without matching (no allele matched), when high- and low-risk groups were analyzed together (p=0.0099). Furthermore, matching for HLA-A allele was significantly beneficial compared with no matching in high-risk transplant recipients (p=0.0154). Nevertheless, no significant effect of HLA-B matching was detected. We conclude that HLA class I, especially HLA-A matching has a beneficial effect for corneal transplant outcome.
- Published
- 2000
48. Overview of the stability and barrier functions of the granitic geosphere at the Kamaishi Mine: relevance to radioactive waste disposal in Japan
- Author
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H. Yoshida, K. Aoki, T. Semba, K. Ota, K. Amano, K. Hama, M. Kawamura, and K. Tsubota
- Published
- 2000
- Full Text
- View/download PDF
49. Investigation of the Efficiency of the Multigrid Method for Finite Element Electromagnetic Field Computations Using Nested Meshes
- Author
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K. Tsubota, Vlatko Cingoski, and Hideo Yamashita
- Subjects
Differential equation ,Computer science ,Iterative method ,Linear system ,Relaxation (iterative method) ,Mixed finite element method ,Electrostatics ,Computer Science::Numerical Analysis ,Finite element method ,Electronic, Optical and Magnetic Materials ,Mathematics::Numerical Analysis ,Nonlinear system ,Algebraic equation ,Multigrid method ,Rate of convergence ,Mesh generation ,Applied mathematics ,Polygon mesh ,Electrical engineering, electronic engineering, information engineering ,Electrical and Electronic Engineering ,Differential algebraic equation ,Extended finite element method ,Multigrid algorithm - Abstract
Investigation of the efficiency of the multigrid solution methods for electromagnetic field computations using nested finite element meshes is presented. Two type of multigrid algorithms, the V-cycle and the W-cycle multigrids are investigated and the results for the convergence rate of the iterative process and the computation time are compared with those of the ICCG solution method which is the commonly used solution method in finite element analysis. It is proven that the efficiency of the multigrid methods is better than that of the ICCG method especially for the solution of large systems of simultaneous algebraic equations.
- Published
- 1999
50. Preferential localization of CD8+ alpha E beta 7+ T cells around acinar epithelial cells with apoptosis in patients with Sjögren's syndrome
- Author
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T, Fujihara, H, Fujita, K, Tsubota, K, Saito, K, Tsuzaka, T, Abe, and T, Takeuchi
- Subjects
Adult ,Receptors, Antigen, T-Cell, alpha-beta ,Lacrimal Apparatus ,Apoptosis ,Epithelial Cells ,CD8-Positive T-Lymphocytes ,Middle Aged ,Salivary Glands ,Immunophenotyping ,Sjogren's Syndrome ,Cell Movement ,T-Lymphocyte Subsets ,Humans ,Female ,Cell Adhesion Molecules - Abstract
The T lymphocytes that infiltrate the exocrine glands in Sjögren's syndrome (SS) play a key role in damaging glandular epithelial cells, but the mechanisms of this damage by T lymphocytes are not fully understood. To determine the cellular basis of this phenomenon, we focused our attention on the T lymphocytes around acinar epithelial cells in SS. We showed that CD8+ but not CD4+ T lymphocytes were located around the acinar epithelial cells and that a majority of these CD8+ T lymphocytes possess an unique integrin, alpha E beta 7 (CD103). The acinar epithelial cell adherent with alpha E beta 7 (CD103)+ CD8+ T lymphocytes was apoptotic. Both the perforin/granzyme B and Fas/Fas ligand pathways were implicated in the process of programmed cell death in lacrimal glands. These results suggested that alpha E beta 7 integrin, by interacting with E-cadherin, mediates the adhesion between CD8+ T lymphocytes and acinar epithelial cells in SS and participates in inducing epithelial cell apoptosis, leading to secretory dysfunction of exocrine glands, a hallmark of SS.
- Published
- 1999
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