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Search Results: 1 - 10 of 165 matches for " Hidetaka Arimura "
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Computer-aided differential diagnosis system for Alzheimer’s disease based on machine learning with functional and morphological image features in magnetic resonance imaging  [PDF]
Yasuo Yamashita, Hidetaka Arimura, Takashi Yoshiura, Chiaki Tokunaga, Ohara Tomoyuki, Koji Kobayashi, Yasuhiko Nakamura, Nobuyoshi Ohya, Hiroshi Honda, Fukai Toyofuku
Journal of Biomedical Science and Engineering (JBiSE) , 2013, DOI: 10.4236/jbise.2013.611137

Alzheimer’s disease (AD) is a dementing disorder and one of the major public health problems in countries with greater longevity. The cerebral cortical thickness and cerebral blood flow (CBF), which are considered as morphological and functional image features, respectively, could be decreased in specific cerebral regions of patients with dementia of Alzheimer type. Therefore, the aim of this study was to develop a computer-aided classification system for AD patients based on machine learning with the morphological and functional image features derived from a magnetic resonance (MR) imaging system. The cortical thicknesses in ten cerebral regions were derived as morphological features by using gradient vector trajectories in fuzzy membership images. Functional CBF maps were measured with an arterial spin labeling technique, and ten regional CBF values were obtained by registration between the CBF map and Talairach atlas using an affine transformation and a free form deformation. We applied two systems based on an arterial neural network (ANN) and a support vector machine (SVM), which were trained with 4 morphological and 6 functional image features, to 15 AD patients and 15 clinically normal (CN) subjects for classification of AD. The area under the receiver operating characteristic curve (AUC) values for the two systems based on the ANN and SVM with both image features were 0.901 and 0.915, respectively. The AUC values for the ANN-and SVM-based systems with the morphological features were 0.710 and 0.660, respectively, and those with the functional features were 0.878 and 0.903, respectively. Our preliminary results suggest that the proposed method may have potential for assisting radiologists in the differential diagnosis of AD patients by using morphological and functional image features.

Computer-Aided Diagnosis Systems for Brain Diseases in Magnetic Resonance Images
Hidetaka Arimura,Taiki Magome,Yasuo Yamashita,Daisuke Yamamoto
Algorithms , 2009, DOI: 10.3390/a2030925
Abstract: This paper reviews the basics and recent researches of computer-aided diagnosis (CAD) systems for assisting neuroradiologists in detection of brain diseases, e.g., asymptomatic unruptured aneurysms, Alzheimer's disease, vascular dementia, and multiple sclerosis (MS), in magnetic resonance (MR) images. The CAD systems consist of image feature extraction based on image processing techniques and machine learning classifiers such as linear discriminant analysis, artificial neural networks, and support vector machines. We introduce useful examples of the CAD systems in the neuroradiology, and conclude with possibilities in the future of the CAD systems for brain diseases in MR images.
Automated measurement of three-dimensional cerebral cortical thickness in Alzheimer’s patients using localized gradient vector trajectory in fuzzy membership maps  [PDF]
Chiaki Tokunaga, Hidetaka Arimura, Takashi Yoshiura, Tomoyuki Ohara, Yasuo Yamashita, Kouji Kobayashi, Taiki Magome, Yasuhiko Nakamura, Hiroshi Honda, Hideki Hirata, Masafumi Ohki, Fukai Toyofuku
Journal of Biomedical Science and Engineering (JBiSE) , 2013, DOI: 10.4236/jbise.2013.63A042

Our purpose in this study was to develop an automated method for measuring three-dimensional (3D) cerebral cortical thicknesses in patients with Alzheimer’s disease (AD) using magnetic resonance (MR) images. Our proposed method consists of mainly three steps. First, a brain parenchymal region was segmented based on brain model matching. Second, a 3D fuzzy membership map for a cerebral cortical region was created by applying a fuzzy c-means (FCM) clustering algorithm to T1-weighted MR images. Third, cerebral cortical thickness was three- dimensionally measured on each cortical surface voxel by using a localized gradient vector trajectory in a fuzzy membership map. Spherical models with 3 mm artificial cortical regions, which were produced using three noise levels of 2%, 5%, and 10%, were employed to evaluate the proposed method. We also applied the proposed method to T1-weighted images obtained from 20 cases, i.e., 10 clinically diagnosed AD cases and 10 clinically normal (CN) subjects. The thicknesses of the 3 mm artificial cortical regions for spherical models with noise levels of 2%, 5%, and 10% were measured by the proposed method as 2.953 ± 0.342, 2.953 ± 0.342 and 2.952 ± 0.343 mm, respectively. Thus the mean thicknesses for the entire cerebral lobar region were 3.1 ± 0.4 mm for AD patients and 3.3 ± 0.4 mm for CN subjects, respectively (p < 0.05). The proposed method could be feasible for measuring the 3D cerebral cortical thickness on individual cortical surface voxels as an atrophy feature in AD.

Threshold Particle Diameters in Miniemulsion Reversible-Deactivation Radical Polymerization
Hidetaka Tobita
Polymers , 2011, DOI: 10.3390/polym3041944
Abstract: Various types of controlled/living radical polymerizations, or using the IUPAC recommended term, reversible-deactivation radical polymerization (RDRP), conducted inside nano-sized reaction loci are considered in a unified manner, based on the polymerization rate expression, R p = k p[M] K[ Interm]/[ Trap]. Unique miniemulsion polymerization kinetics of RDRP are elucidated on the basis of the following two factors: (1) A high single molecule concentration in a nano-sized particle; and (2) a significant statistical concentration variation among particles. The characteristic particle diameters below which the polymerization rate start to deviate significantly (1) from the corresponding bulk polymerization, and (2) from the estimate using the average concentrations, can be estimated by using simple equations. For stable-radical-mediated polymerization (SRMP) and atom-transfer radical polymerization (ATRP), an acceleration window is predicted for the particle diameter range, . For reversible-addition-fragmentation chain-transfer polymerization (RAFT), degenerative-transfer radical polymerization (DTRP) and also for the conventional nonliving radical polymerization, a significant rate increase occurs for . On the other hand, for ?the polymerization rate is suppressed because of a large statistical variation of monomer concentration among particles.
An explicit dimension formula for Siegel cusp forms with respect to the non-split symplectic groups
Hidetaka Kitayama
Mathematics , 2010,
Abstract: The purpose of this paper is to give an explicit dimension formula for the spaces of vector valued Siegel cusp forms of degree two with respect to a certain kind of arithmetic subgroups of the non-split Q-forms of Sp(2,R). We obtain our result by using Hashimoto and Ibukiyama's results in [HI80],[HI83] and Wakatsuki's formula in [Wak]. Our result is a generalization of formulae in [Has84,Theorem 4.1] and [Wak,Theorem 6.1].
On the graded ring of Siegel modular forms of degree two with respect to a non-split symplectic group
Hidetaka Kitayama
Mathematics , 2010,
Abstract: We will give the graded ring of Siegel modular forms of degree two with respect to a non-split symplectic group explicitly.
An explicit PSp_4(3)-polynomial with 3 parameters of degree 40, with an appendix
Hidetaka Kitayama
Mathematics , 2009,
Abstract: We construct an explicit PSp_4(3)-polynomial with 3 parameters of degree 40 by using some results of Siegel modular forms.
Development of Surgical Treatment for Vitreous Disease  [PDF]
Tatsuya Mimura, Hidetaka Noma, Hideharu Funatsu
Surgical Science (SS) , 2012, DOI: 10.4236/ss.2012.311101
Abstract: Vitreous surgery has improved remarkably with various advances in surgical instruments and techniques. The two most important breakthrough in recent years have been the introduction of small-gauge pars plana vitrectomy (PPV) systems and new illumination devices. Compared with traditional 20-gauge PPV, sutureless small-gauge PPV appears to be safer, with a shorter operating time, less postoperative inflammation, less patient discomfort, and more rapid recovery of visual acuity. This article reviews recent progress in the surgical management of vitreous disease with a historical perspective.
Efficient Protein Refolding Using Surfactants at High Final Protein Concentration  [PDF]
Hidetaka Noritomi, Yoshiyuki Kato, Satoru Kato
Journal of Surface Engineered Materials and Advanced Technology (JSEMAT) , 2014, DOI: 10.4236/jsemat.2014.41002

The refolding of denatured hen egg white lysozyme (HEWL) was examined by surfactants at a high final refolded HEWL concentration (1 mg/mL). Hexadecyltrimethylammonium bromide (CTAB) and sucrose fatty acid monoester (DK-SS) were used to dissolve denatured HEWL without denaturants such as guanidine hydrochloride (GuHCl) and urea. When denatured HEWL was perfectly dissolved in buffer solutions containing surfactants and dithiothreitol (DTT), the concentration of CTAB was about one-twentieth times less than that of DK-SS. The concentration of CTAB strongly affected the refolding yield, and the maximum refolding yield was obtained at 0.88 mM CTAB, which is around the critical micelle concentration of CTAB. The refolding yield was influenced by the molar ratio of oxidized glutathione (GSSG) to DTT, and the maximum refolding yield was obtained when [GSSG]/[DTT] was 1.5. The refolding yield was markedly dependent upon the solution pH of HEWL, and exhibited 80% at pH 5.2.

Natural air leak test without submergence for spontaneous pneumothorax
Hidetaka Uramoto, Fumihiro Tanaka
Journal of Cardiothoracic Surgery , 2011, DOI: 10.1186/1749-8090-6-165
Abstract: Between 2005 and 2010, 35 patients underwent a novel method for evaluating air leaks without submergence, and their clinical records were retrospectively reviewed. The data on patient characteristics, surgical details, and perioperative outcomes were analyzed.The differences in the clinical background and intraoperative factors did not reach a statistically significant level between the new and classical methods. The incidence of recurrence was also equivalent to the standard method. However, the length of the operation and drainage periods were significantly shorter in patients evaluated using the new method than the conventional method. Further, no postoperative complications were observed in patients evaluated using the new method.This simple technique is satisfactorily effective and does not result in any complications.SP remains a significant health problem because the recurrence rate is estimated to be approximately 10%-20%, even after surgical management is performed [1]. Prolonged air leaks (PALs) are the main reason for prolonged thoracic tube drainage, a prolonged hospital stay, and increased costs [2]. We often experience postoperative air leaks in spite of there being no air leaks intraoperatively. Therefore, the procedure for evaluating air leaks itself might be a problem.The submersion method, which is the most popular way of screening for air leaks [3], requires that the lung parenchyma be held to identify the leak point. Furthermore, most procedures are performed in a limited space by VATS. However, holding the lung puts it in a state that is far from its natural and physiological state. A practical technique that avoids this unnatural positioning has not been sufficiently discussed. We herein introduce a new technique that uses a transparent film and drainage tube. This method is easy and efficient, and does not appear to cause any complications. The purpose of this study was to determine the clinical outcome using the new method for detecting air l
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