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Sandblasted large grit, acid etched 표면처리에 따른 교정용 미니 임플랜트의 제거회전력에 관한 연구
오남희,김성훈,국윤아,이근혜,강윤구,모성서 대한치과교정학회 2006 대한치과교정학회지 Vol.36 No.5
Sandblasted large grit, acid etched(SLA) 표면처리 된 교정용 미니 임플랜트와 평활면을 가진 교정용 미니 임플랜트 사이에 제거회전력과 조직학적 소견을 통해 표면처리된 교정용 임플랜트의 임상적 가능성에 대하여 알아보고자 하였다. 실험재료로는 길이가 9.5 mm, 외경이 1.8 mm인 custom made, screw shaped, titanium implants가 사용되었다. 미니 임플랜트는 두개의 군으로 분류되었는데 SLA군은 20개의 SLA 표면처리된 미니 임플랜트이었고, 평활면군은 크기와 형태가 같지만 SLA처리공정이 생략되어 제작된 20개의 미니 임플랜트로 구성되었다. 이들은 10마리 가토의 경골에 식립되었다. 각각의 가토의 우측 경골에는 SLA군의 미니 임플랜트 2개가 식립되었고, 좌측 경골에는 평활면군의 미니 임플랜트 2개가 식립되었다. 각 군에는 식립 직후 Ni-Ti coil spring에 의해 약 150 g의 지속적인 견인력이 주어졌다. 식립 6주 후에 10마리의 가토를 희생하였고, 안정된 상태에서 Ni-Ti coil spring을 제거하였으며 digital torque gauge를 이용하여 제거 회전력을 측정하였다. 식립 6주 후에 SLA군의 경우 (8.29 Ncm) 평활면군 (3.34 Ncm)에 비해 더 높은 평균 제거회전력을 나타내었고 조직학적 소견에서도 screw 하방에서의 신생골 형성이 관찰되었다. SLA 표면처리된 미니 임플랜트는 평활면 미니 임플랜트에 비해 좀 더 강한 교정력에 저항할 수 있을 것으로 예상되었다. Objective: The purposes of this study were to evaluate the differences between sand blasted, large grit and acid-etched (SLA) treated mini-implants and smooth surface orthodontic mini-implants in relation to the removal torque as well as the histologic analysis. Methods: Custom-made, screw-shaped, titanium implants with a length of 9.5 mm and an outer diameter of 1.8 mm were divided into 2 groups; the SLA group (20 SLA treated orthodontic mini-implants) and the smooth surface group (20 smooth surface mini-implants), and placed in the tibia metaphysis of 10 rabbits. Each rabbit had 4 mini-implants placed, 2 in each tibia. The right tibia were implanted with the SLA group mini-implants and the left tibia had the smooth group mini-implants placed. Each mini-implant group were immediately applied with a continuous traction force of 150 g using a Ni-Ti coil spring. The rabbits were sacrificed 6 weeks post-surgically. Subsequently, the legs were stabilized, the Ni-Ti coil springs were removed and the mini-implants were removed under reverse torque rotation with a digital torque gauge. Results: 6 weeks after placement, the SLA group presented a higher mean removal torque value (8.29 Ncm) than the smooth group (3.34 Ncm) and histologic analysis revealed a higher new bone formation aspect along the screw in the SLA group. Conclusion: Results of this study indicates that SLA treated mini-implants may endure higher orthodontic forces without loosening.
최헌종,허남환,강은구,이석우,홍원표 한국공작기계학회 2004 한국공작기계학회 추계학술대회논문집 Vol.2004 No.-
Recently, the evolution in production techniques (e.g. high-speed milling) and the complex shapes involved in modern production design has been increasingly popular. The key to the achievement is a drastic improvement of the dynamic behavior of the machine tool axes used in production machinery. The more complex these tool paths the higher the speed and acceleration requirements. But it is very difficult to reach the target for high speed machine tool because of the limitations of servo system and motion control system. However the direct drive design of machine tool axes, which is based on linear motors and which recently appeared on the market, is a viable candidate to meet the ever increasing demands, because of these advantages such as no backlash, less friction, more mechanical simplicity and very higher acceleration and velocity comparing to the traditional system. This paper focused on the performance tests of the high speed horizontal machine tool based on linear motor. Especially, dynamic characteristics were investigated through circular test and circular form machining test is carried out considering many important parameter. Therefore these several experiments is used to be evaluated the model for prediction of circular motion error and circular machined error.
Nam-Goo Kang(Nam-Goo Kang),Jong-Gil Seo(Jong-Gil Seo),Won-Nyeong Cho(Won-Nyeong Cho),Jin-Wook Sung(Jin-Wook Sung) 한국임상움직임치료학회 2022 한국임상움직임치료학회지 Vol.2 No.2
Background Transverse abdominis (TrA) is an important local muscle that plays an essential role in the core. Ultrasound imaging is a reliable and valid technique for analyzing TrA muscle thickness. However, this method requires skilled operators. Biofeedback devices have achieved similar clinical outcomes to ultrasound. Even so, few studies have examined the validity of this biofeedback. Objectives This study aimed to assess whether changes in waist circumference, as determined by changes in the thickness of TrA detected with a stretch sensor made with a biofeedback device, produce results similar to those obtained through ultrasound. Methods Nineteen healthy participants were recruited for this study. Ultrasound measurement of the thickness of TrA was compared with the simultaneous measurement of the stretch sensor biofeedback device. Results Acceptable validity was found between the thickness of the TrA and the stretch sensor displayed on-screen waist circumference (Pearson correlation = -0.69, p = 0.03). Conclusions The study confirmed that changes in the grape bar on the screen of the stretch sensor application could be employed as a suitable indicator for assessing the changes to the thickness of the TrA muscle.
Kang, Nam‐,Goo,Cho, Byungjin,Kang, Beom‐,Goo,Song, Sunghoon,Lee, Takhee,Lee, Jae‐,Suk WILEY‐VCH Verlag 2012 Advanced Materials Vol.24 No.3
<P><B>Electronic devices</B> based on a series of synthesized block copolymers are demonstrated. In particular, a block copolymer system with a lamellar structure exhibits unipolar switching behavior. This study provides a simple strategy based on the adjustment of the block ratio in block copolymers to control the polymer morphology and thus the electrical and switching properties of polymer‐based memory devices.</P>
Kang, Nam‐,Goo,Cho, Byungjin,Kang, Beom‐,Goo,Song, Sunghoon,Lee, Takhee,Lee, Jae‐,Suk WILEY‐VCH Verlag 2012 Advanced Materials Vol.24 No.3
<P>Jae‐Suk Lee, Takhee Lee, and co‐workers investigate on page 385. structural and electrical characteristics of synthesized block copolymers consisting of poly(9‐(4‐vinylphenyl)carbazole)‐b‐poly(2‐vinylpyridine) Various morphologies such as spherical or lamellar structures with microphase separation are obtained. In particular, devices with a lamellar structure exhibited memory switching, which is strongly related to the formation and rupture of highly conductive paths consisting primarily of carbazole segments. </P>
Nam-Goo Kang,Jeong-Hoon Lee,Min-Joo Ko,Won-Jeong Jeong,Sae-Il Oh,Hyo-Seong An 한국임상움직임치료학회 2021 한국임상움직임치료학회지 Vol.1 No.2
Background : Trunk bending requires coordination of the pelvis and hip joints and activation of the gluteal and lower extremity muscles. The gluteus maximus (GM) is an important muscle for trunk bending task and repeated trunk extension increases erector spinae (ES) muscle activity, and these extensors exhibit muscle activity opposite that of the gluteal muscles at a given lumbo-pelvic angle. Elastic band placed around the legs was found to increase GM muscle activity during exercise. Previous studies have compared GM, ES, and HS muscle activities during flexion movements. However, there is no study that applies elastic band during trunk forward bending and compared the activity of the GM, ES and HS muscles. Objectives : The purpose of this study was to investigate muscle activity in the gluteus maximus (GM), erector spinae (ES), and hamstring (HS), as well as hip joint angle during trunk forward bending in a hip abduction exercise using an elastic band. Methods Fourteen healthy women were recruited. Surface electromyographic activity was recorded from the GM, HS, and ES muscles, and hip joint angle was measured using Image J during trunk forward bending while performing a hip abduction exercise using an elastic band. Results : The hip joint angle during the forward bending movement increased significantly when an elastic band was used compared to when it was not. Muscle activity in the GM increased significantly, whereas that in the HS decreased significantly, with the elastic-band intervention. No significant change in ES muscle activity was observed with the band. Conclusions : During trunk forward bending with isometric hip abduction using an elastic band could be beneficial to promote hip joint movement and GM muscle relative to HS muscle activity.
Kang Nam-goo,Jeong Won-jeong,Ko Min-ju,Oh Jae-seop 한국전문물리치료학회 2023 한국전문물리치료학회지 Vol.30 No.2
Background: The gluteus maximus (GM) muscle comprise the lumbo-pelvic complex and is an important stabilizing muscle during leg extension. In patients with low back pain (LBP) with weakness of the GM, spine leads to compensatory muscle activities such as instantaneous increase of the erector spinae (ES) muscle activity. Four-point kneeling arm and leg lift (FKALL) is most common types of lumbopelvic and GM muscles strengthening exercise. We assumed that altered hip position during FKALL may increase thoraco-lumbar stabilizer like GM activity more effectively method. Objects: The purpose of this study was investigated that effects of the three exercise postures on the right-sided GM, internal oblique (IO), external oblique (EO), and multifidus (MF) muscle activities and pelvic kinematic during FKALL. Methods: Twenty eight healthy individuals participated in this study. The exercises were performed three conditions of FKALL (pure FKALL, FKALL with 120° hip flexion of the supporting leg, FKALL with 30° hip abduction of the lifted leg). Participants performed FKALL exercises three times each condition, and motion sensor used to measure pelvic tilt and rotation angle. Results: This study demonstrated that no significant change in pelvic angle during hip movement in the FKALL (p > 0.05). However, the MF and GM muscle activities in FKALL with hip flexion and hip abduction is greater than pure FKALL position (p < 0.001). Conclusion: Our finding suggests that change the posture of the hip joint to facilitate GM muscle activation during trunk stabilization exercises such as the FKALL.