• Journal of the Korean Orthopaedic Association
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• v.55 no.1
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• pp.62-70
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• 2020

Purpose: External tibia torsion and proximal tibial vara have been reported in severe varus deformed osteoarthritis, which is a tibio-femoral angle of more than 20°. The radiology measurements were compared with those of control group and the preoperative and follow-up radiology and clinical results were examined. Materials and Methods: From January 2007 to March 2016, 43 knees from 37 persons, who underwent total knee arthroplasty for a severe varus deformity of more than 20° on the tibio-femoral angle on the standing radiographs and had a follow-up period more than two years, were examined. The mean follow-up period was 45.7 months. The control group, who underwent conservative treatments, had Kellgren-Lawrence grade three osteoarthritis and a tibio-femoral angle of less than 3° varus. The external tibial torsion of enrolled patients and control group were estimated using the proximal tibio-fibular overlap length and the tibial torsion values on computed tomography. The proximal tibia vara was measured using the proximal tibial tilt angle. The preoperative and postoperative proximal tibio-fibular overlap length, tibial torsion value, proximal tibial tilt angle, and hospital for special surgery (HSS) score were evaluated. Results: The mean proximal tibio-fibular overlap length was 18.6 mm preoperatively and 11.2 mm (p=0.031) at the follow-up. The control group had a mean proximal tibio-fibular overlap length of 8.7 mm (p=0.024). The mean tibial torsion value was 13.8° preoperatively and 14.0° (p=0.489) at the follow-up. The control group had a mean tibial torsion value of 21.9° (p=0.012). The mean proximal tibial tilt angle was 12.2° preoperatively and 0° (p<0.01) at the follow-up. The control group had a mean proximal tilt angle of 1.2° (p<0.01). The preoperative tibiofemoral angle and mechanical axis deviation were corrected from preoperative 28.3° and medial 68.4 mm to postoperative 0.7° and medial 3.5 mm (p<0.01, p<0.01), respectively. The HSS scores increased from 34 points of preoperatively to 87 points at the last follow-up (p=0.028). Conclusion: Patients with advanced osteoarthritis with a severe varus deformity of more than 20° had significant increases in the external tibial torsion and varus of the proximal tibia. The tibial torsion value before and after surgery in the enrolled patients was not changed statistically, but good clinical results without complications were obtained.

• The korean journal of orthodontics
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• v.19 no.2
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• pp.7-24
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• 1989

The physical properties of seven sizes of control groups and experimental group in stainless steel orthodontic wires were studied in tension, hardness, bending, torsion and observation of microstructure. The wires (0.40-0.90mm dia.) of round type were tested in the as-received condition. The wires of control groups were TRU-CHROME and REMANIUM, and experimental group was SK wire which was developed by ourselves and made in Korea. The results were as follows; 1. The chemical compositions of control groups and experimental group were austenite stainless steel wires of SOS 304. 2. Higher values of tensile and yield strength in tension were control group I, experimental group, control group II. Maximum tensile and yield strength of experimental group were $203.63{\pm}1.41kg/mm^2$ in 0.70mm diameter and $148.96{\pm}4.88kg/mm^2$ in 0.60mm diameter, and maximum elongation was $5.20{\pm}0.57%$ in 0.45mm diameter. 3. Hardness values of experimental group were similar to control groups. Maximum hardness values were $596.2{\pm}13.66Hv$ in 0.45mm diameter wire of control group I, $590.5{\pm}20.08Hv$ in 0.50mm diameter wire of control group II, and $563.6{\pm}5.35Hv$ in 0.70mm diameter wire of experimental group. 4. Torsion properties of experimental group were similar to control group I and more than control group II. Maximum torsion cycles were $31.8{\pm}2.48$ in 0.45mm diameter of control group I, $17.4{\pm}4.84$ in 0.60mm diameter of control group II, and $24.6{\pm}3.04$ in 0.45mm diameter of experimental group. 5. Maximum bending cycles of experimental group were smaller than control groups. Maximum bending cycles were $9.00{\pm}0.00$ in 0.50mm diameter wire of control group I, $10.0{\pm}0.82$ in 0.40mm diameter wire of control group II, and $8.0{\pm}1.26$ in 0.50mm diameter wire of experimental group. 6. Microstructures of experimental and control groups co-existed with martensited austenite structure and elongated austenite structure. 7. The direction of wire fracture was propagated parallel to torsion direction typically and there was no probability showing wire fracture at inclusions and surface scratches. 8. The type of wire fracture was brittle fracture at initiation site and ductile fracture at core.

• Journal of the Korean Society of Physical Medicine
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• v.9 no.4
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• pp.339-345
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• 2014

PURPOSE: This study is to investigate the effect of 4 weeks of gym ball exercise on the pelvis and spine of women in 20s. METHODS: Randomly selected 10 of 20 subjects are allocated to experimental group who will practice gym-ball exercise while the rest 10 subjects are allocated to control group. Values for pelvic obliquity DL-DR, pelvic torsion DL-DR, pelvic rotation, kyphotic angle ICT-ITL (max), and lordotic angle ITL-ILS (max) were measured through recording using 3-dimensional image analyzer as a preliminary inspection. Gym-ball exercise was implemented 3 sessions a week for 4 weeks. Each session consisted of 10 minutes of warm up exercise, 30 minutes of main exercise, and 10 minutes of cool down exercise totaling 50 minutes. Post inspections were measured after exercise. RESULTS: Experimental group showed statistically significant difference in pelvic obliquity DL-DR, pelvic torsion DL-DR, and kyphotic angle ICT-ITL (max) (p<.05) and values of pelvic obliquity DL-DR showed statistically significant difference between two groups (p<.05). However pelvic rotation, lordotic angle ITL-ILS (max) did not show a significant difference. CONCLUSION: These results showed that gym-ball exercise has positive effect in the pelvic obliquity, torsion and spine kyphotic angle and expected to have positive effect on the body balance, body lineup, and coordination.

• Wind and Structures
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• v.15 no.5
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• pp.423-439
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• 2012

Three common medium- rise building forms were physically tested to study their overall wind induced structural response. Emphasis was placed on the torsional response and its correlation with other peak responses. A higher correlation was found between the peak responses than between the general fluctuating parts of the signals. This suggests a common mechanism causing the peak event, and that this mechanism is potentially different to the mechanism causing the general load fluctuations. The measurements show that about 80% of the peak overall torsion occur simultaneously with the peak overall along wind drag for some generic building shapes. However, the peak torsional response occurs simultaneously with only 30%-40% of the peak overall drag for the rectangular model. These results emphasise the importance of load combinations for building design, which are often neglected in the design of medium sized rigid buildings for which the along-wind drag is dominant. Current design wind loading standards from around the world were evaluated against the results to establish their adequacy for building design incorporating wind-induced torsion effects. Although torsion is frequently neglected, for some structural systems it may become more important.

• Kyungpook Mathematical Journal
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• v.49 no.3
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• pp.419-424
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• 2009

Let J be the Jacobian variety of a hyperelliptic curve over $\mathbb{Q}$. Let M be the field generated by all square roots of rational integers over a finite number field K. Then we prove that the Mordell-Weil group J(M) is the direct sum of a finite torsion group and a free $\mathbb{Z}$-module of infinite rank. In particular, J(M) is not a divisible group. On the other hand, if $\widetilde{M}$ is an extension of M which contains all the torsion points of J over $\widetilde{\mathbb{Q}}$, then $J(\widetilde{M}^{sol})/J(\widetilde{M}^{sol})_{tors}$ is a divisible group of infinite rank, where $\widetilde{M}^{sol}$ is the maximal solvable extension of $\widetilde{M}$.

• The Journal of Korean Physical Therapy
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• v.33 no.5
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• pp.217-223
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• 2021

Purpose: This study sought to identify the effects of coordinative locomotor training (CLT) using elastic bands on the flexibility and body alignment of right-handed baseball players in elementary school. Methods: The subjects were 20 instructed right-handed baseball players in elementary school. They were classified into the experimental group with 10 players (n=10) to be given coordinative locomotor training using elastic bands and the control group with 10 players (n=10). Flexibility was measured by the sit and reach exercise. Body alignment was measured using formetric 4D method to measure the trunk imbalance angle (TI), trunk torsion angle (TT), pelvic tilt angle (PTi), pelvic torsion angle (PTo), pelvic rotation angle (PR), kyphotic angle (Ky), and lordotic angle (Lo). Results: There was a significant increase in the flexibility within the experimental group (p<0.05). after the intervention. There was also a significant increase in the difference between the experimental group and the control group (p<0.05). There was a significant decrease in PR during body alignment in the experimental group after intervention (p<0.05). An analysis of the differences between groups showed a significant decrease in the PR of the experimental group compared to the control group (p<0.05). Conclusion: These findings show that coordinative locomotor training using elastic bands would be effective for enhancing the flexibility and pelvic rotation of elementary school right-handed baseball players.

• Honam Mathematical Journal
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• v.32 no.4
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• pp.651-661
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• 2010

In this paper, we obtain a necessary and sufficient condition for a left invariant connection in the tangent bundle over a closed Lie group with a left invariant metric to be a Yang-Mills connection. Moreover, we have a necessary and sufficient condition for a left invariant connection with a torsion-free Weyl structure in the tangent bundle over SU(2) with a left invariant Riemannian metric g to be a Yang-Mills connection.

• Journal of the Korean Mathematical Society
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• v.39 no.1
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• pp.149-161
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• 2002

We study the torsions in the integral homology of the double loop space of the compact simple Lie groups by determining the higher Bockstein actions on the homology of those spaces through the Bockstein lemma and computing the Bockstein spectral sequence.

• The Journal of Korean Physical Therapy
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• v.26 no.3
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• pp.209-215
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• 2014

Purpose: The purpose of this study is to examine the effects of postural control training using a horseback riding simulation on the spinal alignment of children with cerebral palsy. Methods: This study was conducted with 30 children with cerebral palsy at levels I~IV in the Gross Motor Function Classification System (GMFCS), and they were randomly divided into a control group and a hippotherapy group. Both the control group and the experimental group received NDT for 30 minutes per session, four times per week for ten weeks, while the experimental group also received hippotherapy 15 minutes per session, four times per week for ten weeks, after the neurodevelopmental treatment (NDT). The horseback riding simulators (JOBA, EU7805, Panasonic) used in this study simulated actual horse movements. Trunk imbalance, pelvic torsion, and pelvic tilt were measured in each group before the exercise and five weeks and ten weeks after the beginning of the exercise using a spinal structure analysis system (ABW Mapper). Results: The Intra-group effects on trunk imbalance, pelvic torsion, and pelvic tilt according to the exercise periods after the hippotherapy were tested, and the results showed significant interaction effects between the groups and the periods (p<0.05). Conclusion: The horseback riding simulation exercise was shown to be effective for the spinal alignment of children with cerebral palsy. Therefore, additional studies should be conducted with more children with CP divided by type.

• Journal of International Academy of Physical Therapy Research
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• v.11 no.4
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• pp.2184-2190
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• 2020

Background: Although studies have been conducted on muscle thickness and balance in trunk stabilization exercise and exercise using vibration props, studies on trunk stabilization exercise using active vibration for spinal alignment are still insufficient to draw a conclusion. Objectives: To investigate the effect of trunk stabilization exercise using active vibration on the spinal alignment in adult females. Design: A randomized controlled trial. Methods: Twenty-six adult females were randomly assigned to the experimental group (active vibration) and 13 control groups (active non-vibrating) and exercised three times a week for 8 weeks. Each group was measured for spinal alignment before exercise and 8 weeks after exercise. Spinal alignment, trunk imbalance, pelvic tilt, and pelvic torsion were measured using a spinal alignment analyzer. Results: Trunk imbalance was a significantly different depending on the time in the experimental group and the control group (P<.05). Pelvic tilt was a significant difference between the groups (P<.05). Also, pelvic tilt was a significantly different depending on the time in the experimental group (P<.05), but the control group showed no significant difference (P>.05). Pelvic torsion was no significant difference in both groups (P>.05). Conclusion: This study demonstrates that trunk stabilization exercise using active vibration has a positive effect on the alignment of the spine.