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Pose Normalization for CAD Meshes
Takashi Michikawa,Hiromasa Suzuki,Eiji Ohta,Yuichi Sato,Masayoshi Hashima (사)한국CDE학회 2010 한국CAD/CAM학회 국제학술발표 논문집 Vol.2010 No.8
CAD meshes are used in assembly models for digital mock-up (DMU) applications. They are defined as polygonal meshes, and their pose information is usually lost when they are brought together in a model. Accordingly, this paper presents a simple method of finding good poses for CAD meshes. Since extrusion features can be seen in most such meshes, our method estimates their axes from polygonal meshes. For each triangle in a CAD mesh, voting is applied for the estimated extruding axis, and the local coordinate system of the mesh is determined from the voting result. This approach facilitates the capture of good poses for CAD meshes, whereas PCA-based methods create misalignment in most cases. This paper also demonstrates that our method is efficient for a number of applications in CAD and voxel-based mesh generation.
Mesh Generation of Porous Metals from X-ray Computed Tomography Volume Data
Zhenyu Niu,Hiromasa Suzuki,Yutaka Ohtake,Takashi Michikawa (사)한국CDE학회 2013 한국CAD/CAM학회 국제학술발표 논문집 Vol.2010 No.8
Recently, to meet the requirement of machine industry, there has been an increased focus on the development of porous metal as a high-strength material despite its low density. To evaluate its properties and quality, material testing is usually conducted. However, it is more efficient to perform computer simulation evaluations using finite element analysis. In fact, converting a large piece of porous metal into digitized mesh data is significantly difficult because of its complex inner structure. The X-ray computed tomography scanning technique enables us to obtain the information regarding the internal structure of the metal. Furthermore, a reconstruction algorithm produces volume data of the test object. In general, conventional methods are utilized to generate mesh data from volume data, but a key drawback is that they generate too many elements, resulting in high computational cost. We propose an approach to generate meshes for porous structures by modeling each pore using spheres from volume data. Data conversion is conducted through a series of processes namely labeling, spherical approximation, shape approximation, region segmentation, and meshing. The result verifies the feasibility of the proposed method, which generates shape-approximated and finite-element-simulation-available mesh data using fewer elements.
Mesh generation of porous metals from X-ray computed tomography volume data
Zhenyu Niu,Hiromasa Suzuki,Yutaka Ohtake,Takashi Michikawa 대한기계학회 2014 JOURNAL OF MECHANICAL SCIENCE AND TECHNOLOGY Vol.28 No.7
Recently, to meet the requirement of machine industry, there has been an increased focus on the development of porous metal as ahigh-strength material despite its low density. To evaluate its properties and quality, material testing is usually conducted. However, it ismore efficient to perform computer simulation evaluations using finite element analysis. The X-ray computed-tomography scanningtechnique enables us to obtain the information regarding the internal structure of the metal. Furthermore, a reconstruction algorithm producesvolume data of the test object. In general, conventional methods are utilized to generate mesh data from volume data for finiteelement analysis, but a key drawback is that they generate too many elements, resulting in high computational cost. We propose an approachto generate meshes for porous structures by modeling each pore using spheres from volume data.
Metabolic Syndrome is a Predisposing Factor for Diffuse Idiopathic Skeletal Hyperostosis
Eijiro Okada,Shinichi Ishihara,Koichiro Azuma,Takehiro Michikawa,Satoshi Suzuki,Osahiko Tsuji,Satoshi Nori,Narihito Nagoshi,Mitsuru Yagi,Michiyo Takayama,Takashi Tsuji,Nobuyuki Fujita,Masaya Nakamura 대한척추신경외과학회 2021 Neurospine Vol.18 No.1
Objective: Diffuse idiopathic skeletal hyperostosis (DISH) causes spinal ankylosis, which can result in patients suffering specific spinal fractures that lead to a reduction in the activities of daily life in older patients. Currently, DISH is associated with diabetes mellitus and cardiovascular disease; however, the association between DISH and metabolic syndrome has not been established. The purpose of this study was to investigate a potential association between DISH and metabolic syndrome. Methods: We retrospectively reviewed clinical data from consecutive subjects undergoing the musculoskeletal health medical checkups, and enrolled 327 subjects (174 men and 153 women; mean, 63.4±13.7-years). Subjects who had spinal ankylosis at least 4 contiguous vertebral bodies were classified as the DISH group (n=39) while the others were part of the non-DISH group (n=288). The definition of the metabolic syndrome comes from diagnostic criteria used by the Japanese Society for Internal Medicine. Age, sex, body max index (BMI), hematological evaluation, blood pressure, presence of metabolic syndrome, the visceral fat area on abdominal computed tomography, and spinal epidural lipomatosis (SEL) on magnetic resonance imaging were evaluated. Results: Compared to the non-DISH group, in the DISH group, mean age (DISH group, 74.3 years; non-DISH group, 1.9 years; p<0.001), male prevalence were higher (DISH group, 82.1%; non-DISH group, 49.3%; p<0.001), and BMI was greater (DISH group, 24.8; non-DISH group, 23.0; p=0.006). the metabolic syndrome was more frequently observed in DISH group (28.9%) than in the non-DISH group (16.0%) (p=0.045). The visceral fat area was significantly larger in the DISH group than in the non-DISH group (DISH group, 130.7±58.2 cm2; Non-DISH group, 89.0±48.1 cm2; p<0.001). The prevalence of SEL was similar between the 2 groups (10.3% in the DISH group vs. 8.7% in the non-DISH group; p=0.464). Poisson regression analysis revealed that the metabolic syndrome was significantly associated with DISH with odds ratio of 2.0 (95% confidence interval, 1.0–3.7; p=0.004). Conclusion: Metabolic syndrome was significantly associated with DISH. Our data showed metabolic syndrome is potentially related to DISH.
Yang, Se-Ran,Kim, Sun-Jung,Byun, Kyoung-Hee,Hutchinson, Brian,Lee, Bong-Hee,Michikawa, Makoto,Lee, Yong-Soon,Kang, Kyung-Sun Wiley (John WileySons) 2006 Stem cells Vol.24 No.2
<P>Neural stem cells (NSCs) are capable of giving rise to neurons, glia, and astrocytes. Although self-renewal and differentiation in NSCs are regulated by many genes, such as Notch and Numb, little is known about the role of defective genes on the self-renewal and differentiation of NSCs from developing brain. The Niemann-Pick type C1 (NPC1) disease is a neurodegenerative disease caused by a mutation of the NPC1 gene that affects the function of the NPC1 protein. The ability of NSC self-renewal and differentiation was investigated using a model of NPC1 disease. The NPC1 disorder significantly affected the self-renewal ability of NSCs, as well as the differentiation. NSCs from NPC1-/- mice showed impaired self-renewal ability compared with the NPC1+/+ mice. These alterations were accompanied by the enhanced activity of p38 mitogen-activated protein kinases (MAPKs). Further, the specific p38 MAPK inhibitor SB202190 improved the self-renewal ability of NSCs from NPC-/- mice. This indicated that the NPC1 deficiency can lead to lack of self-renewal and altered differentiation of NSCs mediated by the activation of p38 MAPK, impairing the generation of neurospheres from NPC1-/- Thus, the NPC1 gene may play a crucial role in NSC self-renewal associated with p38 MAPK.</P>
Byun, Kyunghee,Kim, Jaewoo,Cho, Sang-Yun,Hutchinson, Brian,Yang, Se-Ran,Kang, Kyung-Sun,Cho, Moonjae,Hwang, Kyukye,Michikawa, Makoto,Jeon, Young-Wook,Paik, Young-Ki,Lee, Bonghee WILEY-VCH 2006 Proteomics Vol. No.
<P>Niemann-Pick disease type C (NPC) is a fatal autosomal recessive cholesterol disorder characterized by severe progressive neurodegeneration. To unveil the mechanism of neurodegeneration, proteomic and morphological approaches were applied to the hippocampus in NPC –/– mouse. Two-DE was utilized to resolve the hippocampal protein expression profiles of 4- and 8-week-old NPC +/+ and –/– mice. Differentially expressed protein spots were identified by MALDI-TOF MS and database searching. At 4 weeks of age, there was no significant difference in protein profiles between NPC +/+ and –/– mice. However, at the age of 8 weeks, NPC +/+ and –/– mice showed marked difference in protein expressions. Among these, glutamate receptor 2 precursor was identified. The immunohistochemical study on neurotransporters showed that glial GABA transporter (GAT-3) increased in both 4- and 8-week-old NPC –/– mouse and glutamic acid decarboxylase (GAD-6) increased in 8-week-old NPC –/– mouse. Glial glutamate transporter, excitatory amino acids carrier-1 (EAAC1), decreased in 8-week-old NPC –/– mouse. In conclusion, our data may provide insight into the understanding of the basic mechanism through perturbation of protein networks and neurotransporter systems in a single gene knockout model of NPC disease.</P>
( Kazunari Nakahara ),( Chiaki Okuse ),( Seitaro Adachi ),( Keigo Suetani ),( Sarika Kitagawa ),( Miki Okano ),( Yosuke Michikawa ),( Rei Takagi ),( Ryuta Shigefuku ),( Fumio Itoh ) The Editorial Office of Gut and Liver 2013 Gut and Liver Vol.7 No.3
Background/Aims: To evaluate the usefulness and safety of treating disseminated intravascular coagulation (DIC) complicating cholangitis primarily with antithrombin (AT) and thrombomodulin (rTM). Methods: A DIC treatment algorithm was determined on the basis of plasma AT III levels at the time of DIC diagnosis and DIC score changes on treatment day 3. Laboratory data and DIC scores were assessed prospectively at 2-day intervals. Results: DIC reversal rates >75% were attained on day 7. In the DIC reversal group, statistically significant differences from baseline were observed in interleukin- 6 and C-reactive protein levels within 5 days. Patients with no DIC score improvements after treatment with AT alone experienced slow improvement on a subsequent combination therapy with rTM. Although a subgroup with biliary drainage showed greater improvement in DIC scores than did the nondrainage subgroup, the mean DIC score showed improvement even in the nondrainage subgroup alone. Gastric cancer bleeding that was treated conservatively occurred in one patient. As for day 28 outcomes, three patients died from concurrent malignancies. Conclusions: Although this algorithm was found to be useful and safe for DIC patients with cholangitis, it may be better to administer rTM and AT simultaneously from day 1 if the plasma AT III level is less than 70%. (Gut Liver 2013; 7:363-370)