The amphicheiral 2-bridge knots with symmetric union presentations

Toshifumi Tanaka 대한수학회 2024 대한수학회보 Vol.61 No.2

In this paper, we characterize amphicheiral 2-bridge knots with symmetric union presentations and show that there exist infinitely many amphicheiral 2-bridge knots with symmetric union presentations with two twist regions. We also show that there are no amphicheiral 3-stranded pretzel knots with symmetric union presentations.

THE JONES POLYNOMIAL OF KNOTS WITH SYMMETRIC UNION PRESENTATIONS

Toshifumi Tanaka 대한수학회 2015 대한수학회지 Vol.52 No.2

A symmetric union is a diagram of a knot, obtained from diagrams of a knot in the 3-space and its mirror image, which are sym- metric with respect to an axis in the 2-plane, by connecting them with 2-tangles with twists along the axis and 2-tangles with no twists. This paper presents an invariant of knots with symmetric union presentations, which is called the minimal twisting number, and the minimal twisting number of 1042 is shown to be two. This paper also presents a sufficient condition for non-amphicheirality of a knot with a certain symmetric union presentation.

THE JONES POLYNOMIAL OF KNOTS WITH SYMMETRIC UNION PRESENTATIONS

Tanaka, Toshifumi Korean Mathematical Society 2015 대한수학회지 Vol.52 No.2

A symmetric union is a diagram of a knot, obtained from diagrams of a knot in the 3-space and its mirror image, which are symmetric with respect to an axis in the 2-plane, by connecting them with 2-tangles with twists along the axis and 2-tangles with no twists. This paper presents an invariant of knots with symmetric union presentations, which is called the minimal twisting number, and the minimal twisting number of $10_{42}$ is shown to be two. This paper also presents a sufficient condition for non-amphicheirality of a knot with a certain symmetric union presentation.

Discrete element simulations of continental collision in Asia

Tanaka Atsushi,Sanada Yoshinori,Yamada Yasuhiro,Matsuoka Toshifumi,Ashida Yuzuru Korean Society of Earth and Exploration Geophysici 2005 지구물리와 물리탐사 Vol.8 No.1

조립질 물질을 이용한 축소모형실험(예를 들어 모래상자실험)을 다양한 크기의 많은 지질학적 문제에 성공적으로 적용되어왔다. 이러한 물리적 실험은 개별요소법(DEM)을 이용하여 수치적으로도 수행될수 있다. 이연구에서는 현재 지구상에서 가장 중요한 지구조적 과정 중의 하나인 인도판과 유라시아판의 충돌문제를 시뮬레이션하기 위해 개별요소법을 적용하였다. 개별요소 시뮬레이션은 구조지질학뿐만 아니라 토질역학, 암석역학 등의 다양한 동역학적 분야에 적용되어왔다. 조사대상이 많은 작은 입자들의 조합으로 가정되기 때문에 개별요소 시뮬레이션은 거대하고 불연속적인 변형이 일어나는 대상을 다룰 수 있다. 그러나 DEM 시뮬레이션에서는 개개 입자에 대한 입력변수들과 전체 물성의 관계에 대해 거의 알려져 있지 않기 때문에 입력 변수들의 타당성을 검증하기 어려운 경우가 자주 있다. 그러므로 이전의 연구들에서는 시행착오에 의해 입력변수를 조정하여만 하였다. 이러한 어려움을 극복하기 위하여, 이 연구에서는 개별요소 시뮬레이션에 수치적인 이축 시험을 도입하였으며, 이러한 수치 시험 결과를 이용하여 충돌 모델에 사용되는 입력변수의 타당성을 검토하였다. 결과적인 층돌 모델은 동 아시아에서 관측되는 실제 변형과 매우 비슷하며, GPS 자료 및 동 아시아의 원위치 응력자료와 잘 대비된다.

아시아 대륙충돌의 개별요소 시뮬레이션

전중독사 ( Atsushi Tanaka ),진전가전 ( Yoshinori Sanada ),산전태광 ( Yasuhiro Yamada ),송강준문 ( Toshifumi Matsuoka ),호전양 ( Yuzuru Ashida ) 한국지구물리·물리탐사학회 2005 지구물리와 물리탐사 Vol.8 No.1

Discrimination between Malignant and Benign Vertebral Fractures Using Magnetic Resonance Imaging

Tomoyuki Takigawa,Masato Tanaka,Yoshihisa Sugimoto,Tomoko Tetsunaga,Keiichiro Nishida,Toshifumi Ozaki 대한척추외과학회 2017 Asian Spine Journal Vol.11 No.3

Study Design: Retrospective analysis using magnetic resonance imaging (MRI). Purpose: To identify MRI features that could discriminate benign from malignant vertebral fractures. Overview of Literature: Discrimination between benign and malignant vertebral fractures remains challenging, particularly in patients with osteoporosis and cancer. Presently, the most sensitive means of detecting and assessing fracture etiology is MRI. However, published reports have focused on only one or a few discriminators. Methods: Totally, 106 patients were assessed by MRI within six weeks of sustaining 114 thoracic and/or lumbar vertebral fractures (benign, n=65; malignant, n=49). The fractures were pathologically confirmed if malignant or clinically diagnosed if benign and were followed up for a minimum of six months. Seventeen features were analyzed in all fractures’ magnetic resonance images. Single parameters were analyzed using the chi-square test; a logit model was established using multivariate logistic regression analysis. Results: The chi-square test revealed 11 malignant and 4 benign parameters. Multivariate logistic regression analysis selected (i) posterior wall diffuse protrusion (odds ratio [OR], 48; 95% confidence interval [CI], 4.2–548; p =0.002), (ii) pedicle involvement (OR, 21; 95% CI, 2.0–229; p =0.01), (iii) posterior involvement (OR, 21; 95% CI, 1.5–21; p =0.02), and (iv) band pattern (OR, 0.047; 95% CI, 0.0005–4.7; p =0.19). The logit model was expressed as P=1/[1+exp (x)], x=−3.88×(i)−3.05×(ii)−3.02×(iii)+3.05×(iv)+5.00, where P is the probability of malignancy. The total predictive value was 97.3%. The only exception was multiple myeloma with features of a benign fracture. Conclusions: Although each MRI feature had a different meaning with a variable differentiation power, combining them led to an accurate diagnosis. This study identified the most relevant MRI features that would be helpful in discriminating benign from malignant vertebral fractures.

Allopregnanolone suppresses mechanical allodynia and internalization of neurokinin-1 receptors at the spinal dorsal horn in a rat postoperative pain model

( Masahide Fujita ),( Taeko Fukuda ),( Yasuhiro Sato ),( Toshifumi Takasusuki ),( Makoto Tanaka ) 대한통증학회 2018 The Korean Journal of Pain Vol.31 No.1

Background: To identify a new strategy for postoperative pain management, we investigated the analgesic effects of allopregnanolone (Allo) in an incisional pain model, and also assessed its effects on the activities of the primary afferent fibers at the dorsal horn. Methods: In experiment 1, 45 rats were assigned to Control, Allo small-dose (0.16 mg/kg), and Allo large-dose (1.6 mg/kg) groups (n = 15 in each). The weight bearing and mechanical withdrawal thresholds of the hind limb were measured before and at 2, 24, 48, and 168 h after Brennan’s surgery. In experiment 2, 16 rats were assigned to Control and Allo (0.16 mg/kg) groups (n = 8 in each). The degree of spontaneous pain was measured using the grimace scale after the surgery. Activities of the primary afferent fibers in the spinal cord (L6) were evaluated using immunohistochemical staining. Results: In experiment 1, the withdrawal threshold of the Allo small-dose group was significantly higher than that of the Control group at 2 h after surgery. Intergroup differences in weight bearing were not significant. In experiment 2, intergroup differences in the grimace scale scores were not significant. Substance P release in the Allo (0.16 mg/kg) group was significantly lower than that in the Control group. Conclusions: Systemic administration of Allo inhibited mechanical allodynia and activities of the primary afferent fibers at the dorsal horn in a rat postoperative pain model. Allo was proposed as a candidate for postoperative pain management. (Korean J Pain 2018; 31: 10-5)

Impact of Rotation Correction after Brace Treatment on Prognosis in Adolescent Idiopathic Scoliosis

Kentaro Yamane,Tomoyuki Takigawa,Masato Tanaka,Yoshihisa Sugimoto,Shinya Arataki,Toshifumi Ozaki 대한척추외과학회 2016 Asian Spine Journal Vol.10 No.5

Study Design: Level 4 retrospective review. Purpose: Brace treatment is the standard nonoperative treatment for adolescent idiopathic scoliosis (AIS). Rotation correction is also important, because AIS involves a rotation deformity. The purpose of this study was to evaluate the impact of rotation correction after Osaka Medical College (OMC) brace treatment on clinical outcomes in AIS. Overview of Literature: Brace treatment has a significant effect on the progression of AIS. However, few reports have examined rotation correction after brace treatment. Methods: A total of 46 patients who wore the OMC brace were retrospectively reviewed. The curve magnitude was determined according to the Cobb method, and the rotation angle of the apical vertebrae was measured by the modified Nash-Moe method. Based on the difference in the rotation angle before and after the initial brace treatment, patients were divided into two groups. Group A (n=33) was defined as no change or improvement of the rotation angle; group B (n=13) was defined as deterioration of the rotation angle. If the patients had curve or rotation progression of 5° or more at skeletal maturity, or had undergone surgery, the treatment was considered a failure. Results: Differences of rotation angle between before and after the initial brace treatment were 2°±2° in group A and –3°±2° in group B (p <0.001). The rates of treatment failure were 42% in group A and 77% in group B (p <0.05). This study included 25 patients with Lenke type 1 (54%). Group A (24%) with Lenke type 1 also had a significantly better success rate of brace treatment than group B (75%) (p <0.05). Conclusions: Insufficient rotation correction increased brace treatment failure. Better rotation correction resulted in a higher success rate of brace treatment in patients with Lenke type 1.

Three-Dimensional Analysis of the Ideal Entry Point for Sacral Alar Iliac Screws

Watanabe Noriyuki,Takigawa Tomoyuki,Uotani Koji,Oda Yoshiaki,Misawa Haruo,Tanaka Masato,Ozaki Toshifumi 대한척추외과학회 2022 Asian Spine Journal Vol.16 No.6

Study Design: This is a virtual three-dimensional (3D) imaging study examining computed tomography (CT) data to investigate instrumentation placement.Purpose: In this study, we aim to clarify the ideal entry point and trajectory of the sacral alar iliac (SAI) screw in relationship to the dorsal foramen at S1 and the respective nerve root.Overview of Literature: To the best of our knowledge, there is yet no detailed 3D imaging study on the ideal entry point of the SAI screw. Despite the evidence suggesting that the dorsal foramen at S1 is a landmark on the sacrum, the S1 nerve root disruption is a general concern during the insertion of SAI screws. No other study has been published examining the nerve root location at the S1and SAI screw insertions.Methods: Preoperative CT data from 26 patients pertaining to adult spinal deformities were investigated in this study. We applied a 3D image processing method for a detailed investigation. Virtual cylinders were used to mimic SAI screws. These were placed to penetrate the sacral iliac joint without violating the other cortex. We then assessed the trajectory of the longest SAI screw and the ideal entry point of SAI using a color mapping method on the surface of the sacrum. We measured the location of the nerve root at S1 in relation to the foramen at S1 and the sacral surface.Results: As per the results of our color mapping, it was determined that areas that received high scores are located medially and caudally to the dorsal foramen of S1. The mean angle between a horizontal line and a line connecting the medial edge of the foramen and nerve root at S1 was 93.5°. The mean distances from the dorsal medial edge of the foramen and sacral surface to S1 nerve root were 21.8 mm and 13.9 mm, respectively.Conclusions: The ideal entry point of the SAI screw is located medially and caudally to the S1 dorsal foramen based on 3D digital mapping. It is also shown that this entry point spares the S1 nerve root from possible iatrogenic injuries.

Association between Lymphovascular Invasion and Recurrence in Patients with pT1N+ or pT2–3N0 Gastric Cancer: a Multi-institutional Dataset Analysis

Keizo Fujita,Mitsuro Kanda,Seiji Ito,Yoshinari Mochizuki,Hitoshi Teramoto,Kiyoshi Ishigure,Toshifumi Murai,Takahiro Asada,Akiharu Ishiyama,Hidenobu Matsushita,Chie Tanaka,Daisuke Kobayashi,Michitaka F 대한위암학회 2020 Journal of gastric cancer Vol. No.

Purpose: Patients with pathological stage T1N+ or T2–3N0 gastric cancer may experience disease recurrence following curative gastrectomy. However, the current Japanese Gastric Cancer Treatment Guidelines do not recommend postoperative adjuvant chemotherapy for such patients. This study aimed to identify the prognostic factors for patients with pT1N+ or pT2–3N0 gastric cancer using a multi-institutional dataset. Materials and Methods: We retrospectively analyzed the data obtained from 401 patients with pT1N+ or pT2–3N0 gastric cancer who underwent curative gastrectomy at 9 institutions between 2010 and 2014. Results: Of the 401 patients assessed, 24 (6.0%) experienced postoperative disease recurrence. Multivariate analysis revealed that age ≥70 years (hazard ratio [HR], 2.62; 95% confidence interval [CI], 1.09–7.23; P=0.030) and lymphatic and/or venous invasion (lymphovascular invasion (LVI): HR, 7.88; 95% CI, 1.66–140.9; P=0.005) were independent prognostic factors for poor recurrence-free survival. There was no significant association between LVI and the site of initial recurrence. Conclusions: LVI is an indicator of poor prognosis in patients with pT1N+ or pT2–3N0 gastric cancer.