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Search Results: 1 - 10 of 843 matches for " Tomohisa Uchida "
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Advances in Angioscopic Imaging of Vascular Disease  [PDF]
Yasumi Uchida, Yasuto Uchida
World Journal of Cardiovascular Surgery (WJCS) , 2012, DOI: 10.4236/wjcs.2012.24021
Abstract:

Percutaneous angioscopy, using high resolution fiberoptic imaging, allows direct and two-dimensional visualization of the vascular interior, thereby enabling macroscopic pathological diagnosis. Percutaneous angioscopy has revealed that the vascular luminal surface exhibits various colors and morphologies characteristic of different vascular diseases. This imaging technique is used for evaluation of the severity of vascular diseases, staging of atherosclerosis, analysis of thrombus composition, evaluation of interventional and surgical therapies, and for guidance of intravascular interventions such as angioplasty, venous valvuloplasty and aortic stentgrafting. Recently, dye-image angioscopy has been used clinically for analyses of thrombus composition, endothelial damage and plaque composition. Intravascular microscopy was also developed for cellular imaging of vascular disease. Furthermore, fluorescent angioscopy was developed for molecular imaging of substances comprising atherosclerotic plaques. In this article, we describe the history of the development of angioscopy, angioscopic systems and techniques, angioscopic changes associated with vascular diseases, angioscope-guided intravascular therapies, and evaluation of intravascular and surgical therapies. Angioscopic pictures, except those of the coronary arteries, have rarely been published in the literature, so we have included many representative angioscopic pictures obtained by the authors in this article.

Genomic Profiling of Oral Squamous Cell Carcinoma by Array-Based Comparative Genomic Hybridization
Shunichi Yoshioka, Yoshiyuki Tsukamoto, Naoki Hijiya, Chisato Nakada, Tomohisa Uchida, Keiko Matsuura, Ichiro Takeuchi, Masao Seto, Kenji Kawano, Masatsugu Moriyama
PLOS ONE , 2013, DOI: 10.1371/journal.pone.0056165
Abstract: We designed a study to investigate genetic relationships between primary tumors of oral squamous cell carcinoma (OSCC) and their lymph node metastases, and to identify genomic copy number aberrations (CNAs) related to lymph node metastasis. For this purpose, we collected a total of 42 tumor samples from 25 patients and analyzed their genomic profiles by array-based comparative genomic hybridization. We then compared the genetic profiles of metastatic primary tumors (MPTs) with their paired lymph node metastases (LNMs), and also those of LNMs with non-metastatic primary tumors (NMPTs). Firstly, we found that although there were some distinctive differences in the patterns of genomic profiles between MPTs and their paired LNMs, the paired samples shared similar genomic aberration patterns in each case. Unsupervised hierarchical clustering analysis grouped together 12 of the 15 MPT-LNM pairs. Furthermore, similarity scores between paired samples were significantly higher than those between non-paired samples. These results suggested that MPTs and their paired LNMs are composed predominantly of genetically clonal tumor cells, while minor populations with different CNAs may also exist in metastatic OSCCs. Secondly, to identify CNAs related to lymph node metastasis, we compared CNAs between grouped samples of MPTs and LNMs, but were unable to find any CNAs that were more common in LNMs. Finally, we hypothesized that subpopulations carrying metastasis-related CNAs might be present in both the MPT and LNM. Accordingly, we compared CNAs between NMPTs and LNMs, and found that gains of 7p, 8q and 17q were more common in the latter than in the former, suggesting that these CNAs may be involved in lymph node metastasis of OSCC. In conclusion, our data suggest that in OSCCs showing metastasis, the primary and metastatic tumors share similar genomic profiles, and that cells in the primary tumor may tend to metastasize after acquiring metastasis-associated CNAs.
Readout system with on-board demodulation for CMB polarization experiments using coherent polarimeter arrays
Koji Ishidoshiro,Makoto Nagai,Takeo Higuchi,Masaya Hasegawa,Masashi Hazumi,Masahiro Ikeno,Osamu Tajima,Manobu Tanaka,Tomohisa Uchida
Physics , 2011, DOI: 10.1109/TNS.2012.2195029
Abstract: B-modes are special patterns in cosmic microwave background (CMB) polarization. The detection of them is a smoking-gun signature of primordial gravitational waves. The generic strategy of the CMB polarization experiments is to employ a large number of polarimeters for improving the statistics. The Q/U Imaging ExperimenT-II (QUIET-II) has been proposed to detect the B-modes using the world's largest coherent polarimeter array (2,000 channels). An unique detection technique using QUIET's polarimeters, which is a modula- tion/demodulation scheme, enables us directly extracting the polarization signal. The extracted signal is free from non- polarized components and intrinsic 1/f noise. We developed a data readout system with on-board demodulation functions for the QUIET-II experiment. We employed a "master" clock strategy. This strategy guarantees phase matching between the modulation by the polarimeters and the demodulation by ADC modules. The single master generates all carrier clocks and distributes them to each module. The developed electronics, clock modules, and the ADC modules fulfill requirements. Tests with a setup similar to that of the real experiment proved that the system works properly. The performance of all system components are validated to be suitable for B-mode measurements.
Fairness Norms and the Incidence of Environmental Subsidy  [PDF]
Toshihiro Uchida
Modern Economy (ME) , 2012, DOI: 10.4236/me.2012.36100
Abstract: Although fairness concerns are frequently discussed in the real world environmental politics, their effects are relatively neglected in the environmental economics literature. Using a survey method, this paper attempts to reveal how fairness norms affect the incidence of subsidy both in the short-run and long-run. The results indicate that statutory incidence (legal right to receive subsidy) affects people’s fairness norms on who should receive subsidy. In particular it is considered unfair for a firm to receive a part of the subsidy when it is legally granted to the consumer side. If firms avoid behaviors that are considered unfair, the tax and subsidy equivalence theorem may not hold under this situation. The survey results also reveal that fairness norms affect the incidence of subsidy in the long-run, in a sense that the allocation of gains that are generated due to subsidy is affected. People find it fair if allocation is made in proportion to firms’ own effort. Therefore, if an increase in profit is achieved by activities directly supported by subsidy, people find it less justifiable for firms to keep all the gains by themselves and thus firms may be forced to share the gains with consumers.
High-Quality Three-Dimensional Computed Tomography Angiography of Abdominal Viscera with Small Focal Spot, Low Tube Voltage, and Iterative Model Reconstruction Technique  [PDF]
Masafumi Uchida
Open Journal of Radiology (OJRad) , 2015, DOI: 10.4236/ojrad.2015.51002
Abstract: Purpose: To evaluate the quality of three-dimensional (3D) CT angiography images of the abdominal viscera with small focal spot, low tube voltage, and iterative model reconstruction technique (IMR). Materials and Methods: Seven patients with suspected disease of the pancreatobiliary system had undergone CT with high-quality CTA protocol in the present study. There were 5 men and 2 women, ranging in age from 52 to 80 years (mean: 64 years). Results: Depiction of abdominal small artery, small portal vein was possible in all cases. In two cases that we were able to compare, it was superior to standard CTA in small vascular depiction in CTA made clearly in high quality protocol. Conclusions: Although the use of small focal spot, low tube voltage, and IMR can produce higher-quality images of abdominal vessels than standard CTA, this improvement is not significant at elevated radiation doses.
High-Resolution Micro-Siting Technique for Large Scale Wind Farm Outside of Japan Using LES Turbulence Model  [PDF]
Takanori Uchida
Energy and Power Engineering (EPE) , 2017, DOI: 10.4236/epe.2017.912050
Abstract: The spatial distribution of wind speed varies greatly over steep complex terrain, thus the selection of an optimal site in such terrain for wind turbine construction requires great care. We have developed a numerical model for simulating unsteady flows called RIAM-COMPACT (Research Institute for Applied Mechanics, Kyushu University, COM putational Prediction of Airflow over Complex Terrain), which is based on the LES (Large-Eddy Simulation) technique. The computational domain of RIAM-COMPACT can be varied from several meters to several kilometers, and the model is able to predict airflow over complex terrain with high accuracy. The present paper discusses the application of RIAM-COMPACT to the micro-siting of wind turbines at sites outside Japan. The results from two case studies will be presented.
High-Resolution LES of Terrain-Induced Turbulence around Wind Turbine Generators by Using Turbulent Inflow Boundary Conditions  [PDF]
Takanori Uchida
Open Journal of Fluid Dynamics (OJFD) , 2017, DOI: 10.4236/ojfd.2017.74035
Abstract:
We have developed an LES (Large-Eddy Simulation) code called RIAM-COMPACT (Research Institute for Applied Mechanics, Kyushu University, Computational Prediction of Airflow over Complex Terrain). The analysis do-main of this numerical model extends from several meters to several kilometers. The model is able to predict airflow over complex terrain with high accuracy and is also now able to estimate the annual power output of wind turbine generators with the use of field observation data. In the present study, a numerical simulation of turbulent airflow over an existing wind farm was performed using RIAM-COMPACT and high-resolution elevation data. Based on the simulation results, suitable and unsuitable locations for the operation of WTGs (Wind Turbine Generators) were identified. The latter location was subject to the influence of turbulence induced by small topographical variations just upwind of the WTG location.
CFD Prediction of the Airflow at a Large-Scale Wind Farm above a Steep, Three-Dimensional Escarpment  [PDF]
Takanori Uchida
Energy and Power Engineering (EPE) , 2017, DOI: 10.4236/epe.2017.913052
Abstract: The Duogu Wind Farm, China Huadian Group Corporation’s first wind project in Yunnan, China, has been approved by the Provincial Development and Reform Commission. The acquired site is in Mengzi, in the south-east of Yunnan Province. The developer has deployed thirty-three 1.5 MW turbines in this wind farm (49.5 MW), and the total cost of construction has been estimated to be CNY449.7 million ($69.61 million). The present study compared the prediction accuracy of two CFD software packages for simulating flow over an escarpment with a steep slope. The two software packages were: 1) Open FOAM (Turbulence model: SST k-ω RANS), which is a free, open source CFD software package developed by Open CFD Ltd at the ESI Group and distributed by the Open FOAM Foundation and 2) RIAM-COMPACT (Turbulence model: Standard Smagorinsky LES), which has been developed by the lead author of the present paper. Generally good agreement was obtained between the results from the simulations with Open FOAM and RIAM-COMPACT.
Three-Dimensional Numerical Simulation of Stably Stratified Flows over a Two-Dimensional Hill  [PDF]
Takanori Uchida
Open Journal of Fluid Dynamics (OJFD) , 2017, DOI: 10.4236/ojfd.2017.74039
Abstract:
Stably stratified flows over a two-dimensional hill are investigated in a channel of finite depth using a three-dimensional direct numerical simulation (DNS). The present study follows onto our previous two-dimensional DNS studies of stably stratified flows over a hill in a channel of finite depth and provides a more realistic simulation of atmospheric flows than our previous studies. A hill with a constant cross-section in the spanwise (y) direction is placed in a 3-D computational domain. As in the previous 2-D simulations, to avoid the effect of the ground boundary layer that develops upstream of the hill, no-slip conditions are imposed only on the hill surface and the surface downstream of the hill; slip conditions are imposed on the surface upstream of the hill. The simulated 3-D flows are discussed by comparing them to the simulated 2-D flows with a focus on the effect of the stable stratification on the non-periodic separation and reattachment of the flow behind the hill. In neutral (K = 0, where K is a non-dimensional stability parameter) and weakly stable (K = 0.8) conditions, 3-D flows over a hill differ clearly from 2-D flows over a hill mainly because of the three-dimensionality of the flow, that is the development of a spanwise flow component in the 3-D flows. In highly stable conditions (K = 1, 1.3), long-wavelength lee waves develop downstream of the hill in both 2-D and 3-D flows, and the behaviors of the 2-D and 3-D flows are similar in the vicinity of the hill. In other words, the spanwise component of the 3-D flows is strongly suppressed in highly stable conditions, and the flow in the vicinity of the hill becomes approximately two-dimensional in the x and z directions.
Large-Eddy Simulation and Wind Tunnel Experiment of Airflow over Bolund Hill  [PDF]
Takanori Uchida
Open Journal of Fluid Dynamics (OJFD) , 2018, DOI: 10.4236/ojfd.2018.81003
Abstract:
In the present study, wind conditions were numerically predicted for the site of the Bolund hill using the RIAM-COMPACT natural terrain version software, which is based on an LES turbulence model (CFD). In addition, airflow measurements were made using a split-fiber probe in the boundary layer wind tunnel. The characteristics of the airflow at and in the vicinity of the site of the Bolund Experiment were clarified. The study also examined the prediction accuracy of the LES turbulence simulations (CFD). The values of the streamwise (x) wind velocity predicted by the CFD model were generally in good agreement with those from the wind tunnel experiment at all points and heights examined, demonstrating the validity of CFD based on LES turbulence modeling.
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