144 research outputs found

    A generalization of the Lodha-Moore group

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    We generalized the Lodha-Moore group into nn-adic and showed analogues in the Lodha-Moore group of properties between the Thompson group FF and the generalized Thompson group F(n)F(n).Comment: 44 pages, 22 figure

    The 33-colorable subgroup of Thompson's group and tricolorability of links

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    Starting from the work by Jones on representations of Thompson's group FF, subgroups of FF with interesting properties have been defined and studied. One of these subgroups is called the 33-colorable subgroup F\mathcal{F}, which consists of elements whose ``regions'' given by their tree diagrams are 33-colorable. On the other hand, in his work on representations, Jones also gave a method to construct knots and links from elements of FF. Therefore it is a natural question to explore a relationship between elements in F\mathcal{F} and 33-colorable links in the sense of knot theory. In this paper, we show that all elements in F\mathcal{F} give 3-colorable links.Comment: 9 pages, 11 figure

    Alexander's theorem for stabilizer subgroups of Thompson's group

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    In 2017, Jones studied the unitary representations of Thompson's group FF and defined a method to construct knots and links from FF. One of his results is that any knot or link can be obtained from an element of this group, which is called Alexander's theorem. On the other hand, Thompson's group FF has many subgroups and it is known that there exist various subgroups which satisfy or do not satisfy Alexander's theorem. In this paper, we prove that almost all stabilizer subgroups under the natural action on the unit interval satisfy Alexander's theorem.Comment: 14 pages, 13 figure

    Divergence function of the braided Thompson group

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    We prove that the braided Thompson group BVBV has a linear divergence function. By the work of Dru\c{t}u, Mozes, and Sapir, this leads none of asymptotic cones of BVBV has a cut-point.Comment: 35 pages, 25 figure

    NMR分析と計算科学的手法に基づく分子間相互作用部位の迅速な解析法の開発

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    学位の種別: 論文博士審査委員会委員 : (主査)東京大学教授 嶋田 一夫, 東京大学教授 大和田 智彦, 東京大学教授 金井 求, 東京大学教授 船津 高志, 東京大学教授 清水 敏之University of Tokyo(東京大学

    Using the mood disorder questionnaire and bipolar spectrum diagnostic scale to detect bipolar disorder and borderline personality disorder among eating disorder patients

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    Abstract Background Screening scales for bipolar disorder including the Mood Disorder Questionnaire (MDQ) and Bipolar Spectrum Diagnostic Scale (BSDS) have been plagued by high false positive rates confounded by presence of borderline personality disorder. This study examined the accuracy of these scales for detecting bipolar disorder among patients referred for eating disorders and explored the possibility of simultaneous assessment of co-morbid borderline personality disorder. Methods Participants were 78 consecutive female patients who were referred for evaluation of an eating disorder. All participants completed the mood and eating disorder sections of the SCID-I/P and the borderline personality disorder section of the SCID-II, in addition to the MDQ and BSDS. Predictive validity of the MDQ and BSDS was evaluated by Receiver Operating Characteristic analysis of the Area Under the Curve (AUC). Results Fifteen (19%) and twelve (15%) patients fulfilled criteria for bipolar II disorder and borderline personality disorder, respectively. The AUCs for bipolar II disorder were 0.78 (MDQ) and 0.78 (BDSD), and the AUCs for borderline personality disorder were 0.75 (MDQ) and 0.79 (BSDS). Conclusions Among patients being evaluated for eating disorders, the MDQ and BSDS show promise as screening questionnaires for both bipolar disorder and borderline personality disorder.http://deepblue.lib.umich.edu/bitstream/2027.42/112636/1/12888_2012_Article_1235.pd

    Steep posterior slope of the medial tibial plateau is associated with ramp lesions of the medial meniscus and a concomitant anterior cruciate ligament injury

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    Background: Medial meniscus (MM) tears are associated with both acute and chronic anterior cruciate ligament (ACL) insufficiency and can lead to degenerative changes in the knee. ACL reconstruction (ACLR) combined with the meniscal repair was reported to result in decreased anterior knee joint laxity with evidence of improved patient-reported outcomes in the long term. However, a subtle tear of the MM posterior segment, also known as a ramp lesion, is difficult to detect on conventional magnetic resonance imaging (MRI) and is frequently missed in ACL-deficient knees. However, there are few studies about the associations between bone geometry and ramp lesion of the MM. This study aimed to compare sagittal medial tibial slope (MTS), medial tibial plateau depth (MTPD), and coronal tibial slope (CTS) between ACL-injured knees with and without ramp lesion of the MM. We hypothesised that patients with ramp lesion of the MM and a concomitant ACL injury have a steeper MTS and shallower MTPD than those without ramp lesion of the MM. Methods: Twenty-seven patients who underwent ACLR (group A), and 15 patients with combined MM repair (group AM) were included in the study. Anterior tibial translation (ATT) was measured under general anaesthesia just before surgery using a knee arthrometer. MRI was performed in the 10 degrees-knee-flexed position. The MTS and MTPD were measured on sagittal view, and the CTS was measured on coronal view. These parameters were compared between the groups. Differences in MRI measurements or patient demographics between the groups were evaluated using the Mann-Whitney U test. Results: No significant difference was observed in demographic data and post-operative side-to-side difference in ATT between both groups. Pre-operative ATT was significantly higher in group AM than in group A (P = 5.0 degrees than in those with MTS = 5.0 degrees, an occult MM ramp lesion should be strongly suspected, and surgeons should prepare for MM repair in combination with ACLR

    Two simple stitches for medial meniscus posterior root repair prevents the progression of meniscal extrusion and reduces intrameniscal signal intensity better than modified Mason-Allen sutures

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    Purpose Medial meniscus posterior root tears (MMPRTs) can cause severe medial extrusion of the medial meniscus (MMME) and the progression of knee degenerative changes, inducing a high signal intensity of the meniscus on magnetic resonance imaging (MRI). Although MMME and intrameniscal signal intensity (IMSI) reportedly decreased within 3 months after MMPRT repair, no previous studies have reported these changes after a 1-year follow-up. This study aimed to investigate the 1-year postoperative changes in MMME and IMSI on MRI after using different suture techniques. Methods Overall, 33 patients with MMPRT were evaluated, 22 underwent FasT-Fix-dependent modified Mason–Allen suture (F-MMA) repair, and 11 underwent two simple stitches (TSS) repair. MRI examinations were performed preoperatively and 1 year postoperatively. MMME and IMSI were determined using MRI. Results A significant decrease in postoperative MMME was observed in the TSS group (4.1 ± 1.0) relative to that in the F-MMA group (5.1 ± 1.4, P = 0.03). A significant decrease in postoperative IMSI (0.75 ± 0.14) was observed relative to preoperative IMSI in the TSS group (P  Conclusions The most important finding of this study is that TSS repair yielded a greater decrease in MMME and IMSI than F-MMA repair in patients with MMPRT. These results suggest that TSS repair is more useful for restoring loading stress to the posterior horn of the medial meniscus

    Medial meniscus posterior root repairs: A comparison among three surgical techniques in short-term clinical outcomes and arthroscopic meniscal healing scores

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    Background Medial meniscus (MM) posterior root repairs lead to favorable clinical outcomes in patients with MM posterior root tears (MMPRTs). However, there are few comparative studies in evaluating the superiority among several pullout repair techniques such as modified Mason–Allen suture, simple stitch, and concomitant posteromedial pullout repair. We hypothesized that an additional pullout suture at the MM posteromedial part would have clinical advantages in transtibial pullout repairs of the MMPRTs. The aim of this study was to compare the clinical usefulness among several types of pullout repair techniques in patients with MMPRTs. Methods Eighty-three patients who underwent arthroscopic pullout repairs of the MMPRTs were investigated. Patients were divided into three groups using different pullout repair techniques: a modified Mason–Allen suture using FasT-Fix all-inside meniscal repair device (F-MMA, n = 28), two simple stitches (TSS, n = 30), and TSS concomitant with posteromedial pullout repair using all-inside meniscal repair device (TSS-PM, n = 25). Postoperative clinical outcomes and semi-quantitative arthroscopic meniscal healing scores (0–10 points) were evaluated at second-look arthroscopies. Results No significant differences among the three groups were observed in patient demographics and preoperative clinical scores, except for preoperative Lysholm scores. At second-look arthroscopies, there were no significant differences among the three techniques in postoperative clinical outcomes and meniscal healing scores. Conclusions This study demonstrated that the TSS-PM pullout repair technique did not show better scores in postoperative clinical outcomes and meniscal healings compared with the F-MMA and TSS techniques. Our results suggest that the concomitant posteromedial pullout suture may have no clinical advantage in the conventional pullout repairs for the patients with MMPRTs
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