Ultrasonic Sensing of Internal Temperature Distributions in Heated Materials

Manabu Takahashi,Ikuo Ihara 제어로봇시스템학회 2006 제어로봇시스템학회 국제학술대회 논문집 Vol.2006 No.10

True triaxial tests – using permeability and extensional stress parameters to simulate geological history in rocks

Manabu Takahashi,Hyuck Park,Naoki Takahashi,Yukiyasu Fujii 한국자원공학회 2013 Geosystem engineering Vol.16 No.1

In most underground facilities, the existence of water and anisotropic stress can create serious problems when excavating and maintaining the underground cavities. In this article, we performed laboratory experiment of true triaxial tests on Shirahama sandstone to investigate the effect of the intermediate principal stress on rock permeability. In the brittle failure regime (low minimum principal stress), the specimen showed a rapid increase in permeability after brittle fracture. At higher minimum principal stress, the permeability decreased with increasing axial strain, but after yield stress, the permeability recovered gradually small. As a result, the final permeability in the specimen after failure was less than the initial value. We focus on the importance of the intermediate principal stress and introduce the observations related to the mechanical characteristics on a wide range of stress states from confined triaxial compression to confined triaxial extension. The true triaxial test is superior in obtaining continuous deformation behaviors from ductile under a compression regime to brittle under an extension regime. The maximum principal stress increased by a finite amount in changing from a compression state to an extension state.

암석의 X-ray CT 분석 결과와 저 투수성의 비교

김종태,( Manabu Takahashi ),추창오,노병돈,정교철 대한지질공학회 2011 대한지질공학회 학술발표회논문집 Vol.2011 No.-

Permeability change and geometrical information of void spaces in Berea sandstone and Otway sandstone

천대성,Manabu Takahashi,박의섭 한국자원공학회 2017 Geosystem engineering Vol.20 No.1

To clarify the differences in permeability and three-dimensional void geometry in two sandstones, permeability change by increasing confining pressure were measured and three-dimensional geometrical information with microfocus X-ray CT were analyzed. In this research, Berea sandstone and Otway sandstone were used as a specimen, and its total porosity measured by mercury intrusion porosimetry were 17.4 and 25.0%, respectively. Pore size distribution in both sandstones was almost same as one modal manner, but Otway sandstone specimen showed slightly narrow peak of 5 μ–7 μm. Permeability change in both sandstones was decreased with increasing effective confining pressure, but the absolute value in Otway sandstone was lower by one order of magnitude than those in Berea sandstone. Three-dimensional medial axis (3MDA) method was adopted to compare pore geometry in two sandstones and tortuosity, number of connecting paths were decided. Based on this information, we evaluated the relationship between permeability and pore structures.

Cervical Spondylotic Amyotrophy: Case Series and Review of the Literature

Toshiyuki Takahashi,Junya Hanakita,Manabu Minami,Yosuke Tomita,Tomoki Sasagasako,Ryo Kanematsu 대한척추신경외과학회 2019 Neurospine Vol.16 No.3

Objective: Cervical spondylotic amyotrophy (CSA) is a relatively rare entity caused by cervical degenerative spinal diseases and characterized by motor weakness accompanied by remarkable muscle atrophy in the upper extremities without significant sensory deficits or spastic paraparesis in the lower extremities. Postoperative outcomes and predictive prognostic factors vary among previous reports. In the present report, we describe the surgical results in patients who were surgically treated for CSA and present a literature review. Methods: In total, 33 patients with CSA were retrospectively analyzed. Correlations between the surgical outcome and the following factors were statistically analyzed: age, sex, type of impaired muscle, preoperative severity of motor weakness, number of levels of cord or root compression, presence of a T2 high-intensity area in the spinal cord, cervical kyphosis, and methods of surgical procedure. Results: On postoperative neurological evaluation, 25 patients (75.8%) had favorable outcomes and 8 had unfavorable outcomes (proximal type, 72.2%; distal type, 78.6%). Patients with favorable outcomes were significantly younger than those with unfavorable outcomes (p=0.013). Patient’s characteristics except for age and radiological factors were not correlated to surgical outcome. Conclusion: The present study focused on the surgical results in patients who were surgically treated for CSA along with updated information from a literature review. Improvement of motor weakness is expected with acceptable prevalence although higher age can be a negative factor. Surgical outcomes and predictive factors related to a poor prognosis were determined and compared with those of previous articles.

Endoscopic Findings and Treatment of Gastric Neoplasms in Familial Adenomatous Polyposis

Sato Chihiro,Takahashi Kazuya,Sato Hiroki,Naruse Takumi,Nakajima Nao,Takatsuna Masafumi,Mizuno Ken-ichi,Hashimoto Satoru,Takeuchi Manabu,Yokoyama Junji,Kobayashi Masaaki,Terai Shuji 대한위암학회 2022 Journal of gastric cancer Vol.22 No.4

Purpose Gastric neoplasia is a common manifestation of familial adenomatous polyposis (FAP). This study aimed to elucidate the clinical characteristics, endoscopic features including fundic gland polyposis (FGPsis), and treatment outcomes of gastric neoplasms (GNs) in patients with FAP. Materials and Methods A total of 35 patients diagnosed with FAP, including nine patients from four pedigrees who underwent esophagogastroduodenoscopy (EGD), were investigated regarding patient characteristics, GN morphology, and treatment outcomes. Results Twenty-one patients (60.0%) had 38 GNs; 33 (86.8%) and 5 (13.2%) were histologically diagnosed with adenocarcinoma and adenoma, respectively. There were no specific patient characteristics related to GNs. Nodule-type GNs were more prevalent in patients with FGP than without (52.2% vs. 0.0%, P=0.002) in the upper body of the stomach. Conversely, depressed-type GNs were fewer in patients with FGPsis than in those without (13.0% vs. 73.3%, P<0.001). Slightly elevated-type GNs were observed in both groups (34.8% vs. 20.0%, P=0.538). Even within pedigrees, the background gastric mucosa and types of GNs varied. In total, 24 GNs were treated with endoscopic submucosal dissection (ESD) and eight with endoscopic mucosal resection (EMR). EMR was selected for GNs with FGPsis because of the technical difficulty of ESD, resulting in a lower en bloc resection rate (62.5% vs. 100%, P=0.014). Conclusions Our study indicates the necessity of routine EGD surveillance in patients diagnosed with FAP. Notably, the morphology and location of GNs differed between patients with and without FGPsis. Endoscopic treatment and outcomes require more attention in cases of FGPsis. Purpose Gastric neoplasia is a common manifestation of familial adenomatous polyposis (FAP). This study aimed to elucidate the clinical characteristics, endoscopic features including fundic gland polyposis (FGPsis), and treatment outcomes of gastric neoplasms (GNs) in patients with FAP. Materials and Methods A total of 35 patients diagnosed with FAP, including nine patients from four pedigrees who underwent esophagogastroduodenoscopy (EGD), were investigated regarding patient characteristics, GN morphology, and treatment outcomes. Results Twenty-one patients (60.0%) had 38 GNs; 33 (86.8%) and 5 (13.2%) were histologically diagnosed with adenocarcinoma and adenoma, respectively. There were no specific patient characteristics related to GNs. Nodule-type GNs were more prevalent in patients with FGP than without (52.2% vs. 0.0%, P=0.002) in the upper body of the stomach. Conversely, depressed-type GNs were fewer in patients with FGPsis than in those without (13.0% vs. 73.3%, P<0.001). Slightly elevated-type GNs were observed in both groups (34.8% vs. 20.0%, P=0.538). Even within pedigrees, the background gastric mucosa and types of GNs varied. In total, 24 GNs were treated with endoscopic submucosal dissection (ESD) and eight with endoscopic mucosal resection (EMR). EMR was selected for GNs with FGPsis because of the technical difficulty of ESD, resulting in a lower en bloc resection rate (62.5% vs. 100%, P=0.014). Conclusions Our study indicates the necessity of routine EGD surveillance in patients diagnosed with FAP. Notably, the morphology and location of GNs differed between patients with and without FGPsis. Endoscopic treatment and outcomes require more attention in cases of FGPsis.

Endoscopic Findings and Treatment of Gastric Neoplasms in Familial Adenomatous Polyposis

Sato, Chihiro,Takahashi, Kazuya,Sato, Hiroki,Naruse, Takumi,Nakajima, Nao,Takatsuna, Masafumi,Mizuno, Ken-ichi,Hashimoto, Satoru,Takeuchi, Manabu,Yokoyama, Junji,Kobayashi, Masaaki,Terai, Shuji The Korean Gastric Cancer Association 2022 Journal of gastric cancer Vol.22 No.-

Purpose: Gastric neoplasia is a common manifestation of familial adenomatous polyposis (FAP). This study aimed to elucidate the clinical characteristics, endoscopic features including fundic gland polyposis (FGPsis), and treatment outcomes of gastric neoplasms (GNs) in patients with FAP. Materials and Methods: A total of 35 patients diagnosed with FAP, including nine patients from four pedigrees who underwent esophagogastroduodenoscopy (EGD), were investigated regarding patient characteristics, GN morphology, and treatment outcomes. Results: Twenty-one patients (60.0%) had 38 GNs; 33 (86.8%) and 5 (13.2%) were histologically diagnosed with adenocarcinoma and adenoma, respectively. There were no specific patient characteristics related to GNs.Nodule-type GNs were more prevalent in patients with FGP than without (52.2% vs. 0.0%, P=0.002) in the upper body of the stomach. Conversely, depressed-type GNs were fewer in patients with FGPsis than in those without (13.0% vs. 73.3%, P<0.001). Slightly elevated-type GNs were observed in both groups (34.8% vs. 20.0%, P=0.538). Even within pedigrees, the background gastric mucosa and types of GNs varied. In total, 24 GNs were treated with endoscopic submucosal dissection (ESD) and eight with endoscopic mucosal resection (EMR). EMR was selected for GNs with FGPsis because of the technical difficulty of ESD, resulting in a lower en bloc resection rate (62.5% vs. 100%, P=0.014). Conclusions: Our study indicates the necessity of routine EGD surveillance in patients diagnosed with FAP. Notably, the morphology and location of GNs differed between patients with and without FGPsis. Endoscopic treatment and outcomes require more attention in cases of FGPsis.

Walking-Evoked Erection in Patients with Lumbar Degenerative Diseases: Eight Cases and Review of the Literature

Hirota Kengo,Hanakita Junya,Takahashi Toshiyuki,Kanematsu Ryo,Ueno Manabu,Kasuya Hidetoshi,Minami Manabu 대한척추외과학회 2021 Asian Spine Journal Vol.15 No.2

Study Design: Narrative review with a case illustration.Purpose: The purpose of this study was to evaluate the pathogenesis and outcome of therapy for walking-evoked erection in patients with lumbar degenerative diseases.Overview of Literature: Cauda equina compression due to lumbar degenerative diseases rarely cause a walking-evoked erection; however, no review has been undertaken of walking-evoked erection in patients with lumbar degenerative diseases.Methods: A total of 1,570 male patients with lumbar degenerative diseases, who underwent surgery between April 2003 and June 2017, were evaluated; from these patients, participants with walking-evoked erection were selected. Preoperative clinical data of walking-evoked erection, paresthesia, and bladder and bowel function were assessed. In our study, the neurological status and the erectile function of each participant were retrospectively evaluated before and after surgery using the Japanese Orthopedic Association score and the Overactive Bladder Symptom Score.Results: Among the 1,570 male patients screened in our department, eight patients (0.51%, 8/1,570) presented with walking-evoked erection accompanied by cauda equina symptoms. In six of the patients, the erectile symptoms were associated with paresthesia in the genitalia or perianal region. Of the six patients evaluated for bladder dysfunction, all were diagnosed with prostatic hyperplasia, while four were diagnosed with an overactive bladder. In all patients, walking-evoked erection disappeared entirely after surgery.Conclusions: This study comprises the first review of walking-evoked erection in patients with lumbar degenerative diseases. We speculate that sensory input, such as paresthesia in the genitalia or perianal region stimulates the pelvic or perineal nerves through the pudendal nerve and induces reflexogenic erections.

기술보고 : 미소 촛점 X선 CT를 이용한 암석 내 공극의 분포 및 공극률 분석

정교철 ( Gyo Cheol Jeong ),( Manabu Takahashi ) 대한지질공학회 2010 지질공학 Vol.20 No.4

암석에서의 풍화 및 투수성은 방사성폐기물 지하동굴처분 및 암반구조물의 안정성 확보 및 장기적 관리측면에서 매우 중요한 역할을 한다. 이들 암석의 풍화 및 투수성은 암석의 내부구조 특성에 따라 크게 영향을 받는다. 즉 암석 내부의 공극, 미소크랙 등의 양적 정도에 의해 풍화가 빨리 진행되기도 한다. 또한 암석 내부구조의 양적 평가는 그 암석의 풍화 정도를 정량적으로 평가할 수 있는 수단이 되기도 한다. 따라서 암석의 내부구조를 3차원적으로 정확하게 파악한다는 것은 암반구조물의 장기적 관리 측면에서 매우 중요하다고 하겠다. 이 연구는 국내 신선한 화강암과 풍화된 화강암을 대상으로 X선 CT촬영을 실시하여 3차원적으로 공극의 분포를 분석하였다. 분석 결과는 암석 내부의 공극의 분포와 공극률을 잘 표현하고 있다. Weathering and permeability in rocks play a very important role in underground disposal of radioactive waste and their long-term management as well as stability security of rock structures. Weathering and permeability of rocks are largely controlled by the characters of inner structures of rocks. In other words, weathering rate can be accelerated depending on the quantity of pore and microcrack in rocks. Quantitative evaluation of inner structures of rocks can serve as a tool that can assess the degree of weathering of rocks. Therefore it can be said that the understanding of three dimensional distribution of the inner structure of rocks is important for long-term management of rock structures. This study was performed to analyze three dimensional distribution of pore in rocks using Micro Focus X-ray CT on fresh granite and weathered granite from Korea. Results of the analysis clearly show distribution of pore and porosity of the inner rock.

미소 촛점 X선 CT를 이용한 암석의 내부구조 분석

김종태 ( Jong Tae Kim ),( Manabu Takahashi ),박혁 ( Hyuck Park ),안창완 ( Chang Wan Ahn ),이창주 ( Chang Ju Lee ),김만일 ( Man Il Kim ),강미아 ( Mee A Kang ),추창오 ( Chang Oh Choo ),노병돈 ( Byung Don Ro ),정교철 ( Gyo Cheol 대한지질공학회 2010 대한지질공학회 학술발표회논문집 Vol.2010 No.-