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Search Results: 1 - 10 of 919 matches for " Kiyoshi Takahara "
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Predictors of Success for Stone Fragmentation and Stone-Free Rate After Extracorporeal Shockwave Lithotripsy in the Treatment of Upper Urinary Tract Stones
Kiyoshi Takahara,Naokazu Ibuki,Teruo Inamoto,Hayahito Nomi
Urology Journal , 2012,
Abstract: PURPOSE: To evaluate factors affecting the success rate of stone fragmentation and stone-free rate after extracorporeal shockwave lithotripsy (SWL) in treatment of upper urinary tract stones. MATERIALS AND METHODS: A total of 121 patients with upper urinary tract calculi underwent SWL treatment. RESULTS: Success rate of stone fragmentation after SWL was 73.6% (89/121). In 89 patients who had success of breaking stones, 71 patients were followed up for the assessment of stone-free status, of whom 51 (71.8%) patients were stone-free at 3-month follow-up. Among four prognostic factors, including body mass index (BMI), stone size, stone position, and hydronephrosis, BMI and stone position had a significant impact on the success rate of stone fragmentation (P = .04 and U1: P = .0108, respectively). Among five prognostic factors of BMI, stone size, stone position, hydronephrosis, and times of SWL treatments, stone size was the only factor with significant impact on the stone-free rate (middle: P = .0229). CONCLUSION: Our study suggests that stone fragmentation and stone-free rate after SWL treatment for upper urinary tract stones can be predicted.
Suzaku Observation of the Diffuse X-Ray Emission from the Open Cluster Westerlund 2: a Hypernova Remnant?
Yutaka Fujita,Kiyoshi Hayashida,Hiroaki Takahashi,Fumio Takahara
Physics , 2009, DOI: 10.1093/pasj/61.6.1229
Abstract: We present the analysis of Suzaku observations of the young open cluster Westerlund 2, which is filled with diffuse X-ray emission. We found that the emission consists of three thermal components or two thermal and one non-thermal components. The upper limit of the energy flux of the non-thermal component is smaller than that in the TeV band observed with H.E.S.S. This may indicate that active particle acceleration has stopped in this cluster, and that the accelerated electrons have already cooled. The gamma-ray emission observed with H.E.S.S. is likely to come from high-energy protons, which hardly cool in contrast with electrons. Metal abundances of the diffuse X-ray gas may indicate the explosion of a massive star in the past.
Properties of the Brightest Cluster Galaxy and Its Host Cluster
Haruyoshi Katayama,Kiyoshi Hayashida,Fumio Takahara,Yutaka Fujita
Physics , 2002, DOI: 10.1086/346126
Abstract: We investigate the relation between the properties of Brightest Cluster Galaxies (BCGs) and those of their host clusters. To quantify the properties of cluster hot gas, we employ the parameter $Z$ of the fundamental plane of X-ray clusters. It is found that the offset of the BCG from the peak of cluster X-ray emission is larger for smaller $Z$ clusters. The parameter $Z$ (not the redshift {\it z}), which mainly depends on virial density $\rho_{\rm {vir}}$, is considered to represent the formation epoch of a cluster. We thus consider that the offset of the BCG is correlated with the dynamical equilibrium state of its host cluster. On the contrary, no significant correlation is found between the absolute optical magnitude of the BCG and the parameter $Z$. If the extreme brightness of the BCG is mainly acquired in the course of cluster evolution by environmental effect, BCGs are expected to be brighter in large $Z$ clusters. Our result is not consistent with this simplified view. On the contrary, it is possible that the extreme brightness of the BCG is likely to be determined in the early history of cluster collapse.
A Radiotherapy Treatment Margin Formula When Systematic Positioning Errors are Relatively Small Compared to Random Positioning Errors: A First-Order Approximation  [PDF]
Kiyoshi Yoda
International Journal of Medical Physics,Clinical Engineering and Radiation Oncology (IJMPCERO) , 2017, DOI: 10.4236/ijmpcero.2017.62017
Abstract: A radiotherapy treatment margin formula has been analytically derived when a standard deviation (SD) of systematic positioning errors Ʃ is relatively small compared to an SD of random positioning errors σ. The margin formula for 0 Ʃ σ was calculated by linearly interpolating two boundaries at Ʃ = 0 and Ʃ = σ, assuming that the van Herk margin approximation of k1Ʃ + k2σ is valid at Ʃ = σ. It was shown that a margin formula for 0 Ʃ σ may be approximated by k1σ + k2Ʃ, leading to a more general form of k1 max(Ʃ,σ) + k2 min(Ʃ,σ) which is a piecewise linear approximation for any values of Ʃ and σ.
Development of Charging Infrastructure and Subsidies for Promoting Electric Vehicles  [PDF]
Kiyoshi Arakawa
Theoretical Economics Letters (TEL) , 2018, DOI: 10.4236/tel.2018.811131
Abstract: This paper clarifies an effect of policy on the development of charging infrastructure and subsidies for promoting electric vehicles (EVs). Due to the long-term function of charging infrastructure, this paper constructs a multiple-period model to analyze policy effects on the diffusion of EVs from a long-term perspective. This paper shows that charging infrastructure and subsidy encourage innovation on increasing the battery capacity of EVs. Because intertemporal cost allocation can be executed in the development of a charging infrastructure with a subsidy, a policy with a long-term perspective can enhance the charging infrastructure and promote EVs effectively.
Characteristic X-ray Variability of TeV Blazars: Probing the Link between the Jet and the Central Engine
Jun Kataoka,Tadayuki Takahashi,Stefan J. Wagner,Naoko Iyomoto,Philip G. Edwards,Kiyoshi Hayashida,Susumu Inoue,Greg M. Madejski,Fumio Takahara,Chiharu Tanihata,Nobuyuki Kawai
Physics , 2001, DOI: 10.1086/322442
Abstract: We have studied the rapid X-ray variability of three extragalactic TeV gamma-ray sources; Mrk 421, Mrk 501 and PKS 2155-304. Analyzing the X-ray light curves obtained from ASCA and/or RXTE observations between 1993 and 1998, we have investigated the variability in the time domain from 10^3 to 10^8 sec. For all three sources, both the power spectrum density (PSD) and the structure function (SF) show a roll-over with a time-scale of the order of 1 day or longer, which may be interpreted as the typical time-scale of successive flare events. Although the exact shape of turn-over is not well constrained and the low-frequency (long time-scale) behavior is still unclear, the high-frequency (short time-scale) behavior is clearly resolved. We found that, on time-scales shorter than 1 day, there is only small power in the variability, as indicated by a steep power spectrum density of f^{-2~-3}. This is very different from other types of mass-accreting black-hole systems for which the short time-scale variability is well characterized by a fractal, flickering-noise PSD (f^{-1~-2}). The steep PSD index and the characteristic time-scale of flares imply that the X-ray emitting site in the jet is of limited spatial extent; D > 10^{17} cm distant from the base of the jet, which corresponds to > 100 Schwarzschild radii for 10^{7-10} M_solar black-hole systems.
New aspects of the C5a receptor  [PDF]
Hiroshi Nishiura, Kiyoshi Ohura
Advances in Bioscience and Biotechnology (ABB) , 2014, DOI: 10.4236/abb.2014.51009
Abstract:

The process of apoptotic cell death for maintenance of cell homeostasis is now believed to be flexible. To examine the mechanism for this flexibility, the process of programmed cell death is sometimes divided into three phases: initiation, effector and execution. We have demonstrated that apoptotic cells commonly express a de novo synthesized C5a receptor (C5aR), which belongs to the G protein-coupled receptor (GPCR) family. A natural agnostic ligand of the C5aR, C5a, is produced from plasma C5 by C5 convertase in the early phase of acute inflammation. Although it is not realistic, we found that C5a can adjust apoptotic cell lifespan long. We recently have read interesting reports that apoptotic cells can release natural agnostic ligands at the initiation phase and corresponding GPCRs are already expressed on cell surfaces of apoptotic cells. Conversely, we found that apoptotic cells commonly release an alternative antagonistic/agnostic ligand of the de novo synthesized C5aR, ribosomal protein S19 (RP S19) polymer. The RP S19 polymer can adjust apoptotic cell lifespan short. Importantly, the C5a-dependent regulation is limited by the C5aR sensitization, but the RP S19 polymer-dependent regulation is unlimited by the C5aR desensitization. Therefore, we suggested that apoptotic cells commonly release agnostic ligands in the initiation phase that should lengthen intermittently a period of the initiation phase. Next, apoptotic cells commonly release antagonistic/agnostic ligands in the effector phase that should continue shortening a period of the effector phase. In addition, we know that an inherited erythroblastopenia is associated with mutations in the RP S19 gene. However, the roles of RP S19 in the formation of erythroblast-macrophage islands are not clearly understood. We recently have found that a different arm that the RP S19 polymer has connects the de novo synthesized C5aR on erythroblasts and the generally expressed C5aR on macrophages. There

Analysis of Activities of Adults with Aphasia at Community-Based Rehabilitation Training  [PDF]
Kiyoshi Nosu, Ayuko Shigeta
Journal of Biosciences and Medicines (JBM) , 2015, DOI: 10.4236/jbm.2015.312002
Abstract:

Aphasia is a higher brain dysfunction that affects the production or comprehension of speech and the ability to read or write. The purpose of this research is to establish support guidelines based on a questionnaire survey and a language activity analysis of rehabilitation training so that volunteers can more easily assist disabled persons with aphasia. The focus of this study was the non-profit community-based intervention group Yokohama Aphasia Partner Group, which consists of members with aphasia, their families, speech-language-and-hearing therapists, psychiatric social workers, and volunteers. The following results were obtained. (1) Members with aphasia participate in the Partner Group because they can meet others with aphasia on a regular basis as well as participate in the aphasia rehabilitation program with the recovery of language functions. In addition to medical treatment, the community-based support, which improves the environment and other life contextual factors, is important for rehabilitation. (2) An individual with aphasia shows different language actions, and so an individually different support system in accordance with language activity is necessary.

A Pilot Study of Antibody Drug Therapy to Regulate Cell Adhesion in Dental Implants  [PDF]
Mariko Kawai, Kiyoshi Ohura
Open Journal of Stomatology (OJST) , 2017, DOI: 10.4236/ojst.2017.711046
Abstract: Dental implant therapy is a highly effective treatment for recovering occlusion after tooth loss. An important factor in the success of dental implants is establishing strong osseointegration. If more epithelial cells migrate to the implant-bone interface than mesenchymal stem cells, effective osseointegration may fail. Therefore, controlling epithelial cell adhesion and motility would be an effective strategy to increase the success rate of osseointegration. Laminin-332 is a major component of the basement membrane and is composed of three chains (α3, β3 and γ2). It is well-known that laminin-332 regulates cellular functions such as adhesion, proliferation, apoptosis and differentiation. These biological functions depend on changes in the structural arrangement of laminin-332 by proteolytic cleavage. It is well-known that cleavage of the α3 chain between its LG domains gives laminin-332 its biological function. In this study, we focused on LG domain cleavage and developed antibodies that target the LG domain cleavage site. We attempted to change the biological function of laminin-332 to control cell adhesion for the purpose of regulating dental implant therapy.
Effects of Neutral Particles on Modified Shocks at Supernova Remnants
Yutaka Ohira,Fumio Takahara
Physics , 2009, DOI: 10.1088/2041-8205/721/1/L43
Abstract: H-alpha emission from supernova remnants (SNRs) implies the existence of neutral hydrogens in the ambient medium. In the precursor of an SNR shock modified by cosmic rays (CRs), upstream plasmas are pushed by the CR pressure, but neutral particles are not, so that the relative velocity appears and some neutral particles become pickup ions by the charge exchange process in the precursor. We investigate how the pickup ions generated in the precursor affect the shock structure and the particle acceleration. If the CR pressure is larger than 20% of the shock ram pressure, the compression of the subshock becomes smaller than that without pickup ions because of the pressure of the pickup ions. Moreover, even if the shock is modified by CRs, the total compression ratio can be smaller than 4. In addition, the pickup ions play an important role for the injection into the particle acceleration. If the shock is a quasi-perpendicular shock and if the the multiply reflected ion acceleration occurs, the CR spectrum can be harder than that of the test particle diffusive shock acceleration below GeV.
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