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Feasibility of Improved Attenuation Correction for SPECT Reconstruction in the Presence of Dense Materials Using Dual-Energy Virtual Monochromatic CT: A Phantom Study

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Open Journal of Medical Imaging 2015年第4期5卷 183-193页

作者： sachiko yamada Takashi Ueguchi Eku Shimosegawa Koichi Fujino Takeshi Shimazu Kenya Murase Jun Hatazawa Department of Radiology Osaka University Hospital Osaka Japan Department of Medical Physics and Engineering Osaka University Graduate School of Medicine Osaka Japan Center for Information and Neural Networks National Institute of Information and Communications Technology Osaka Japan Graduate School of Frontier Biosciences Osaka University Osaka Japan Department of Molecular Imaging in Medicine Osaka University Graduate School of Medicine Osaka Japan Department of Traumatology and Acute Critical Medicine Osaka University Graduate School of Medicine Osaka Japan Department of Nuclear Medicine and Tracer Kinetics Osaka University Graduate School of Medicine Osaka Japan

Objective: Computed tomography (CT)-based attenuation correction (CTAC) offers the clear benefit of reliable reconstruction of single-photon emission computed tomography (SPECT) images through its ability to achieve object-specific attenuation maps, but artifacts from dense materials often deteriorate CTAC performance. Therefore, we investigate the feasibility of CTAC in the presence of dense materials using dual-energy virtual monochromatic CT data. Methods: A sodium pertechnetate-filled cylindrical uniform phantom, with a pair of undiluted iodine syringes attached, is scanned with a dual-source CT scanner to obtain both single-energy (120 kVp) polychromatic and dual-energy (80 kVp/140 kVp with tin filtering) virtual monochromatic CT images. The single-energy and the dual-energy CT images are then converted to attenuation maps at 141 keV. SPECT images are reconstructed from 99mTc emission data of the phantom using each single-energy and dual-energy attenuation map and incorporating CTAC procedure. A region-of-in- terest analysis is performed to quantitatively compare the attenuation maps between the single-energy and the dual-energy techniques, each at an iodine-free position and a position adjacent to the iodine solutions. Results: At the iodine-free position, the phantom provides a uniform distribution of attenuation maps in both the single-energy and the dual-energy techniques. In the presence of adjacent iodine solutions, however, severe artifacts appeare in the single-energy CT images. These artifacts make attenuation values fluctuate, resulting in erroneous pixel values in the CTAC SPECT images. In contrast, dual-energy CT strongly suppresses the artifacts and hence improves the uniformity of the attenuation maps and the resultant SPECT images. Conclusions: Dual-energy CT with virtual monochromatic reconstruction has the potential to substantially reduce artifacts arising from dense materials. It has the potential to improve the accuracy of attenuation maps a

关键词： SPECT Attenuation Correction Dual-Energy CT Virtual Monochromatic Imaging Artifact Reduction

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Elastography for the pancreas: Current status and future perspective

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World Journal of Gastroenterology 2016年第14期22卷 3712-3724页

作者： Natsuko Kawada sachiko Tanaka Department of Gastroenterology Nissay Hospital Osaka 550-0012 Japan Osaka Center for Cancer and Cardiovascular Diseases Prevention Osaka 550-0012 Japan

Elastography for the pancreas can be performed by either ultrasound or endoscopic ultrasound(EUS). There are two types of pancreatic elastographies based on different principles, which are strain elastography and shear wave elastography. The stiffness of tissue is estimated by measuring the grade of strain generated by external pressure in the former, whereas it is estimated by measuring propagation speed of shear wave, the transverse wave, generated by acoustic radiation impulse(ARFI) in the latter. Strain elastography is difficult to perform when the probe, the pancreas and the aorta are not located in line. Accordingly, a fine elastogram can be easily obtained in the pancreatic body but not in the pancreatic head and tail. In contrast, shear wave elastography can be easily performed in the entire pancreas because ARFI can be emitted to wherever desired. However, shear wave elastography cannot be performed by EUS to date. Recently, clinical guidelines for elastography specialized in the pancreas were published from Japanese Society of Medical Ultrasonics. The guidelines show us technical knacks of performing elastography for the pancreas.

关键词： Elastography Pancreas Strain Shear wave

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The stay coefficient: a novel quantification of the relationship between stay time and travel time for urban shopping behavior analysis

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Geo-Spatial Information Science 2023年第1期26卷 44-57页

作者： Takashi yamada Department of Human Factors Engineering and Environmental Design Faculty of Biology-Oriented Science and TechnologyKindai UniversityWakayamaJapan

Shoppers typically want to spend an amount of time at a destination that is proportional to the travel time required to arrive there;thus,the travel time can be considered the cost of their *** is likely to be the case across regions with different urban structures and *** purpose of this study was therefore to analyze the shopping behaviors contained in travel survey data from three metropolitan areas in Japan to identify common patterns and indicators based on travel time and stay time,thereby obtaining an understanding to inform future trade area *** the travel time and stay time associated with shopping behavior were found to be log-normally distributed regardless of metropolitan area,and four shopping behavior patterns common among the metropolitan areas were ***“stay coeffi-cient”was then defined to express the elasticity of stay time according to travel time,and its values were similar according to shopping behavior pattern regardless of metropolitan *** stay coefficient proposed in this study can therefore be applied to identify shopping behavior patterns in any urban area based on the relationship between travel time and stay time,realizing a novel approach to the analysis of and marketing for trade areas when planning the construction or renovation of commercial *** approach can help inform the decisions of urban policy makers,marketing advisors,and commercial facility operators,and should be of interest to researchers and practitioners working with geospatial,shopping,and other human behavioral characteristics.

关键词： Travel survey shopping behavior travel time stay time stay coefficient trade area analysis

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Production of asexual and sexual offspring in the triploid sexual planarian Dugesia ryukyuensis

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Integrative Zoology 2009年第3期4卷 265-271页

作者： Kazuya KOBAYASHI sachiko ARIOKA Motonori HOSHI Midori MATSUMOTO Department of Biosciences and Informatics Keio UniversityYokohamaJapan

Certain freshwater planarians reproduce asexually as well as sexually,and their chromosomal ploidies include polyploidy,aneuploidy and ***,we successfully performed an experiment in which a clonal population produced by asexual reproduction of the Dugesia ryukyuensis(OH strain)switched to the sexual mode of *** of this strain are triploid with a pericentric inversion on Chromosome *** worms were switched to sexual reproduction after being fed with sexually mature Bdellocephala brunnea,which is a sexually reproducing *** resulting sexualized OH strain produced cocoons filled with several *** putative factors,Mendelian factor(s)and chromosomal control(s),have been proposed as determining the reproductive *** present study demonstrated that inbreeding of the resultant sexualized worms produced the following four types of offspring through sexual reproduction:diploid asexual worms,triploid asexual worms,diploid sexual worms and triploid sexual *** chromosomal mutation on Chromosome 4 was inherited by these offspring independent of their reproductive *** results provide two important pieces of information:(i)the putative genetic factor was not necessarily inherited in a Mendelian fashion;and(ii)the reproductive mode is not regulated by chromosomal changes such as polyploidy or chromosomal *** suggests that asexuality in *** is regulated by an unknown factor(s)other than a Mendelian factor or a chromosomal control.

关键词： asexuality Dugesia ryukyuensis planarian polyploidy reproductive mode.

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An Inverse Laplace Transform on Lattice Spacing

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Chinese Physics Letters 2013年第3期30卷 32-35页

作者： Hirofumi yamada Division of Mathematics and Science Chiba Institute of TechnologyShibazono 2-1-1NarashinoChiba 275-0023Japan

An inverse Laplace transform on lattice spacing is introduced as a computational framework of the extrapolation of the strong coupling expansion to the scaling *** apply the transform to the two-dimensional nonlinear O(N)model at N≥3 and show that the approximation of the continuum limit of the susceptibility agrees with the existing theoretical and Monte Carlo data.

关键词： apply spacing susceptibility

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Analysis of shopping behavior characteristics in the Keihanshin metropolitan area in Japan based on a person trip survey

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Geo-Spatial Information Science 2020年第4期23卷 305-315页

作者： Takashi yamada Takumi Hayashida Department of Human Factors Engineering and Environmental Design Faculty of Biology-Oriented Science and TechnologyKindai UniversityKinokawaWakayamaJapan

This study analyzed weekday shopping behavior from a home base to a destination using data from the 4th Keihanshin metropolitan area person trip *** first analyzed the relationships between occupation and transportation means,transportation means and travel time,and transportation means and duration of time at the *** of a chi-square test,residual analysis,and correspondence analysis confirmed that employed persons tend to travel by cars while unemployed persons tend to travel by bus or *** relationship between travel time and duration of time at the destination was also revealed according to transportation *** of a cluster analysis then classified shopping behaviors to expose four ***,multiple regression analyzed the degree to which certain variables were related to duration of time at the *** confirmed a strong relationship between duration of time at the destination and travel *** degree of this factor’s influence on other variables was also *** value of these findings is that the relationship between travel time by means of transportation and the duration of time at the destination was clarified using statistical *** then found a highly accurate equation that estimates the duration of time at a destination from the travel *** the duration of time at a destination can be estimated,it may be possible to more accurately develop the structure of rest facilities,the number of parking lots,the degree of congestion,and so on,which can be associated with the customer’s usage behavior in a shopping *** research in this paper contributes to the field of urban analysis and marketing by presenting a new effective method for person trip survey and analysis.

关键词： Person trip survey shopping behavior transportation means travel time duration of time at a destination

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Antibunching and blinking from a single colloidal CdSe quantum dot

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Science China(Physics,Mechanics & Astronomy) 2010年第9期53卷 1619-1625页

作者： yamada Toshiki Kobe Advanced Research Center National Institute of Information and Communications Technology

We have investigated the optical properties of single CdSe/ZnS nanocrystals by conducting combinations of experiments on antibunching and photoluminescence intermittence under different experimental *** on photoluminescence in an antibunching experiment,we analyzed the emission lifetime of QDs by using stretched *** difference between the parameters obtained from average lifetimes and stretched exponents were analyzed by considering the effect of nonradiative *** Auger-assisted tunneling model was used to explain the power law exponents of off time *** power law exponent under high excitation power was correlated with a higher Auger ionization *** the parameters obtained from stretched exponential function and power law,the antibunching phenomena at different time and under different excitation intensity were analyzed.

关键词： single photon source quantum dot lifetime

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Supra-angular biopsy is more reliable for atrophy recognization:analysis of 1598 cases for gastric mucosal histological examination

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World Journal of Gastroenterology 2000年第6期6卷 893-897页

作者： Nobutaka yamada Department of Pathology First Hospital of Nippon Medical SchoolTokyoJapan

INTRODUCTIONChronic gastritis might be a disease of the highestmorbidity in the *** Warren and Marshallsuccessfully isolated and cultured Helicobacter pylori(***)from a gastric antrum biopsy,intensive researches produ... 详细信息

关键词： Helicobacter pylori gastric mucosa/pathology biopsy gastroscopy gastritis atrophic/pathology metaplasia

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Birth after intracytoplasmic sperm injection of ejaculated spermatozoa from a man with mosaic Klinefelter's syndrome

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Asian Journal of Andrology 2005年第2期7卷 217-220,页

作者： Takuya Akashi Hideki Fuse Yasuo Kojima Mikiko Hayashi sachiko Honda Department of Urology Faculty of MedicineToyama Medical and Pharmaceutical UniversityToyamaJapan Department of Obsterics and Gynecology Toyama Prefectural Central HospitalToyamaJapan Toyama Institute of Health ToyamaJapan

Aim:To report a birth after intracytoplasmic sperm injection (ICSI) of ejaculated spermatozoa from a man with mosaic Klinefelter's syndrome detected by fluorescence in situ hybridization (FISH) ***:A 35-year- old man with a normal appearance consulted our hospital because of sterility over a 5-year *** analysis showed low-incidence mosaic Klinefelter's *** FISH,96 % hyperploidy of the lymphocytes was *** examined the sex chromosome of the ejaculated *** FISH,we examined 200 ejacu- lated spermatozoa and no hyperploidy was ***:The 33-year-old female partner of the male patient underwent an uncomplicated controlled ovarian hyperstimulation sequence using a combined recombinant-follicle stimulating hormone (rec-FSH) + human menopausal gonadotrophin (hMG) protocol,following late luteal phase pituitary down *** culminated in the retrieval of seven oocytes,six of which were fertilized with ICSI. One ICSI attempt led to clinical pregnancy with a healthy baby ***:We report a male patient with low- incidence mosaic Klinefelter's syndrome whose ejaculated spermatozoa were identified as being haploid by FISH before ICSI,leading to the successful pregnancy of his wife and the birth of a healthy baby girl.

关键词： Klinefelter's syndrome intracytoplasmic sperm injection fluorescence in situ hybridization

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Clothing skirt designed on conical truss model

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Advances in Manufacturing 2013年第2期1卷 130-135页

作者： Eri Nakayama sachiko Ishida Yu-Jing Liao Ichiro Hagiwara Organization for the Strategic Coordination of Research and Intellectual Property Meiji University8114-21-1NakanoNakano-kuTokyo 164-8525Japan

Several applications of Origami have been tested in industrial area. However, Origami based design is found only in lamp shade and wrapping in design area, and has not been practically applied especially in clothing. In this paper, the conical truss model is applied in the clothing skirt, and the simulation software from 2D to 3D is developed by parametric Origami module （POM）. Finally, the pattern is copied on felt clothing, and the scaled model of skirt on the basis of conical reverse truss model design is made.

关键词： Origami Conical truss model ParametricOrigami module (POM)

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