• Title/Summary/Keyword: Oblique

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Finite Element Stress Analysis of Implant Prosthesis of Internal Connection System According to Position and Direction of Load (임플랜트-지대주의 내측연결 시스템에서 하중의 위치 및 경사에 따른 임플랜트 보철의 유한요소 응력분석)

  • Jang, Jong-Seok;Jeong, Yong-Tae;Chung, Chae-Heon
    • Journal of Dental Rehabilitation and Applied Science
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    • v.21 no.1
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    • pp.1-14
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    • 2005
  • The purpose of this study was to assess the loading distributing characteristics of implant prosthesis of internal connection system(ITI system) according to position and direction of load, under vertical and inclined loading using finite element analysis (FEA). The finite element model of a synOcta implant and a solid abutment with $8^{\circ}$ internal conical joint used by the ITI implant was constructed. The gold crown for mandibular first molar was made on solid abutment. Each three-dimensional finite element model was created with the physical properties of the implant and surrounding bone. This study simulated loads of 200N at the central fossa in a vertical direction (loading condition A), 200N at the outside point of the central fossa with resin filling into screw hole in a vertical direction (loading condition B), 200N at the centric cusp in a $15^{\circ}$ inward oblique direction (loading condition C), 200N at the in a $30^{\circ}$ inward oblique direction (loading condition D) or 200N at the centric cusp in a $30^{\circ}$ outward oblique direction (loading condition E) individually. Von Mises stresses were recorded and compared in the supporting bone, fixture, and abutment. The following results have been made based on this study: 1. Stresses were concentrated mainly at the ridge crest around implant under both vertical and oblique loading but stresses in the cancellous bone were low under both vertical and oblique loading. 2. Bending moments resulting from non-axial loading of dental implants caused stress concentrations on cortical bone. The magnitude of the stress was greater with the oblique loading than with the vertical loading. 3. An offset of the vertical occlusal force in the buccolingual direction relative to the implant axis gave rise to increased bending of the implant. So, the relative positions of the resultant line of force from occlusal contact and the center of rotation seems to be more important. 4. In this internal conical joint, vertical and oblique loads were resisted mainly by the implant-abutment joint at the screw level and by the implant collar. Conclusively, It seems to be more important that how long the distance is from center of rotation of the implant itself to the resultant line of force from occlusal contact (leverage). In a morse taper implant, vertical and oblique loads are resisted mainly by the implant-abutment joint at the screw level and by the implant collar. This type of implant-abutment connection can also distribute forces deeper within the implant and shield the retention screw from excessive loading. Lateral forces are transmitted directly to the walls of the implant and the implant abutment mating bevels, providing greater resistance to interface opening.

A Study on the Usefulness of the New Foot Oblique Projection (새로운 발 사방향 검사법의 유용성에 관한 연구)

  • Kim, Min-Suk;Joo, Young-Cheol;Lee, Seung-Keun
    • Journal of radiological science and technology
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    • v.44 no.5
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    • pp.443-449
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    • 2021
  • In this study, the purpose is to present the foot inclination angle for realizing an image similar to that of the existing examination method and to present the clinical usefulness of the new examination method through comparison between the existing examination method and the newly designed standing foot oblique projection. A foot phantom was used, and the magnification of the image according to the angle was quantitatively evaluated by attaching a nut to the position of the cuboid of the phantom. The internal oblique image acquired using a 30° wedge was set as the standard image. And that image was compared with the images acquired by changing the angle of the foot from 20° to 65° at intervals of 5°. Image evaluation was performed by 3 radiological technologists, and qualitative evaluation using a Likert 5-point scale for evaluation items of true oblique view and quantitative evaluation of the value obtained by measuring the diameter of a nut in each image were performed as image evaluation. For data analysis, reliability analysis between the measure and comparative analysis of the average value for each angle were performed. The qualitative evaluation score for each image was 4.5 to 5 points for most questions in the case of the standard image. And 4 points or less for most questions in the images with a foot angle of 45° or less, and an evaluation score close to the standard image was obtained in the image of 50° or more. And in the quantitative evaluation, the diameter of the nut was measured to be 9.28~9.56 mm. The qualitative evaluation showed a reliability of 0.95~1.0 and the quantitative evaluation was 0.62. As a result of comparing and analyzing the average of the quantitative and qualitative average values for each angle image, the group with the average value most similar to the standard image was images obtained at 55° and 60°, and in the post-analysis, the images of both groups were the same group as the standard image(p<0.01). As a result of this study, it was found that the angle of inclination of the foot for realizing the image most similar to the existing image in the standing foot oblique projection is 55°~60°. In addition, if this test method is applied to the clinic, it is believed that it will help prevent safety accidents such as falls during the test and improve test efficiency by minimizing the movement of patients for the test.

A Study on the Active Force of Extraocular Muscles (외안근의 운동력에 관한 연구)

  • Kim, Sang-Moon
    • Journal of Korean Ophthalmic Optics Society
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    • v.15 no.1
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    • pp.117-122
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    • 2010
  • Purpose: The purpose of this study was to measure the active force of extraocular muscles on mono- and binocular movements for 62 healthy koreans (male: 29, female: 33). Methods: The force of adduction, abduction, elevation and depression, of right and left eye on monocular movement were tested with horizontal moving distance based on corneal limbus and the force of superior oblique muscle and inferior oblique muscle on binocular movement were measured with vertical moving distance between corneal limbus. The distances were obtained by high resolution digital image processing. Results: At monocular movements of tested subjects. the power of abduction, adduction, elevation and depression of right and left eye were (male) 9.35 nun, 9.75 mm, (female) 9.02 mm, 9.52 mm, (male) 10.23 mm, 10.16 mm, (female) 10.17 mm, 10.07 mm, (male) 7.01 mm,6.91 mm, (female) 6.98 mm, 6.64 mm, (male) 7.52 mm, 6.82 mm, (female) 7.52 mm, 6.67 mm, respectively. The active force of binocular movements were 54.8% hyperergasia and 45.1% hypergasia/67.7% hyperergasia and 32.2% hypergasia with inferior oblique muscle, 64.5% hyperergasia and 35.5% hypergasia/58.1% hyperergasia and 41.9% hypergasia with superior oblique muscle, respectively. Conclusions: The force of horizontal movement was higher than vertical movement. The value of adduction was higher than abduction on horizontal movement, and the value of depression was higher than elevation on vertical movement. In the both of inferior and superior oblique muscle, the ratio of hyperergasia was higher than that of hypergasia.

Experiment on Camera Platform Calibration of a Multi-Looking Camera System using single Non-Metric Camera (비측정용 카메라를 이용한 Multi-Looking 카메라의 플랫폼 캘리브레이션 실험 연구)

  • Lee, Chang-No;Lee, Byoung-Kil;Eo, Yang-Dam
    • Journal of the Korean Society of Surveying, Geodesy, Photogrammetry and Cartography
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    • v.26 no.4
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    • pp.351-357
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    • 2008
  • An aerial multi-looking camera system equips itself with five separate cameras which enables acquiring one vertical image and four oblique images at the same time. This provides diverse information about the site compared to aerial photographs vertically. The geometric relationship of oblique cameras and a vertical camera can be modelled by 6 exterior orientation parameters. Once the relationship between the vertical camera and each oblique camera is determined, the exterior orientation parameters of the oblique images can be calculated by the exterior orientation parameters of the vertical image. In order to examine the exterior orientation of both a vertical camera and each oblique cameras in the multi-looking camera relatively, calibration targets were installed in a lab and 14 images were taken from three image stations by tilting and rotating a non-metric digital camera. The interior orientation parameters of the camera and the exterior orientation parameters of the images were estimated. The exterior orientation parameters of the oblique image with respect to the vertical image were calculated relatively by the exterior orientation parameters of the images and error propagation of the orientation angles and the position of the projection center was examined.

Effect of hip positions in frontal plane on abdominal muscle activities during bridging exercise (교각운동시 이마면에서 엉덩관절 위치가 배근육 근활성도에 미치는 영향)

  • Lee, Won-Hwee
    • Journal of the Korea Academia-Industrial cooperation Society
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    • v.20 no.3
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    • pp.224-230
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    • 2019
  • The purpose of this study is to investigate the effect of the hip positions in frontal plane on abdominal muscle activities during bridging exercise. Twenty six subjects who have healthy conditions were asked to perform bridging exercise in three starting positions which are hip abduction, neutral and hip adduction. We used surface electromyography to compare the activities of both external oblique, internal oblique and rectus abdominis muscle. We analyzed the data by using repeated one way ANOVA, The alpha level was set at 0.05. The results showed that the muscle activities of both sides of external oblique, and internal oblique were significantly different among three starting positions. The activity of both sides of rectus abdominis were insignificantly different among three positions. The muscle activities of both sides of external oblique muscle and left internal oblique in bridging exercise with hip adduction position were significantly greater than hip neutral positions. The muscle activity of right internal oblique in bridging exercise with hip abduction positions. Our results suggest that bridging exercise with hip adduction position is recommended to lumbar stabilization exercise and the factor of hip position is important for controlling exercise intensity when designing bridging exercise program.

Comparison of Trunk Muscle Activity during Static Standing Position and Standing Position on Therapeutic Climbing Wall (정적기립자세와 치료적 클라이밍 기립자세 시 체간근 근활성도의 비교)

  • Kim, Se-Hun;Lee, Jeong-In
    • The Journal of Korean Physical Therapy
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    • v.26 no.1
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    • pp.27-32
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    • 2014
  • Purpose: The purpose of the study was to comparison of trunk muscle activity during static standing position and standing position on therapeutic climbing wall of adult. Methods: Study subject is arbitrarily classified into 10 of experimental group and 10 control group among 20 of adult. Trunk activity measured as rectus abdominalis, external oblique, internal oblique, erector spinae. Control group maintains that center of gravity of trunk pass the front of shoulder, pelvis, knee and ankle on stable surface with putting legs apart more than shoulder width. Experimental group had static exercise on 4 by 3 meter, 90 degree of Therapeutic climbing wall. Starting position is that putting arms and legs apart more than shoulder width. In order to compare the effect of it between the groups, independent t-test was used. Results: According to the test result, significant difference between among rectus abdominalis, erector spinae the experimental groups. And external oblique, internal oblique muscle atvity is no significant difference experimental groups between among the control groups was observed. Conclusion: Trunk muscle activation is activated to standing position on the Therapeutic Climbing Wall more than static standing position.

Effects of Bridge Exercise with Pelvic Compression Belt on Electromyographic Activities of Selected Lumbopelvic Muscles in Young Adults with Lumbar Instability

  • Cha, Hyun-Gyu;Choe, Yu-Won;Wu, Yan-Ting;Kim, Myoung-Kwon
    • Journal of the Korean Society of Physical Medicine
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    • v.12 no.3
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    • pp.1-10
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    • 2017
  • PURPOSE: This study assessed the effect of the pelvic compression belt on the electromyographic activity of erector spinae (ES), internal oblique (IO), rectus femoris (RF), and biceps femoris (BF) after bridge exercise with pelvic belt compression in subjects with lumbar instability. METHODS: Forty subjects with lumbar instability volunteered for this study. We asked them to perform the bridge exercise while wearing a pelvic belt compression for 30 minutes five times weekly over a six week period. The pelvic compression belt was adjusted just below the anterior superior iliac spines with stabilizing pressure using elastic compression bands during bridge position. Surface electromyographic data were collected from the erector spinae (ES), internal oblique (IO), rectus femoris (RF) and biceps femoris (BF). RESULTS: After the six week intervention, the experimental group improved significantly. Muscle activation significantly decreased in the erector spinae, rectus femoris, and biceps femoris, and increased in the internal oblique muscle in bridge position while wearing a PCB (P <.01). CONCLUSION: Our findings suggest that the bridge exercise with pelvic belt compression is helpful to reduce activation in superficial muscles and lower extremity muscles such as erector spinae (ES), rectus femoris (RF), biceps femoris (BF) and increase activation in deep trunk muscle such as the internal oblique (IO).

Effects of Active Vibration Exercise on Trunk Muscle Activity, Balance, and Activities of Daily Living in Patients with Chronic Stroke

  • Lee, Dong-Kyu;Kim, Eun-Kyung
    • The Journal of Korean Physical Therapy
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    • v.30 no.4
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    • pp.146-150
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    • 2018
  • Purpose: This study aimed to investigate the effect of active vibration exercise on trunk muscle activity, balance, and activities of daily living in patients with chronic stroke. Methods: Twenty-four patients with chronic stroke were randomly assigned to an experimental (n=12) or a control (n=12) group. The experimental group performed an active vibration exercise workout for 20 minutes a day five times a week for 4 weeks using a flexi-bar. Trunk muscle activity was measured using surface electromyography. Balance was measured using the Berg balance scale. Activities of daily living were measured using the functional independence measure. Results: The intragroup comparison showed significant differences in the rectus abdominis, internal oblique, and external oblique muscle activity values, Berg balance scale score, and functional independence measurement values in the experimental group. The intergroup comparison showed that differences in the rectus abdominis and internal oblique external oblique muscle values, Berg balance scale score, and functional independence measurement value for the experimental group were significantly related to those in the control group. Conclusion: Based on these results, this study proved that the active vibration exercise effectively improved trunk muscle activity, balance, and activities of daily living in patients with chronic stroke.

Measurement of secondary electron emission coefficient(${\gamma}$) with oblique low energy ion and work function ${\phi}_{\omega}$ of theMgO thin film in AC-PDPs

  • Park, W.B.;Lim, J.Y.;Oh, J.S.;Jeong, H.S.;Jung, K.B.;Jeon, W.;Cho, G.S.
    • 한국정보디스플레이학회:학술대회논문집
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    • 2004.08a
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    • pp.507-510
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    • 2004
  • Oblique ion-induced secondary electron emission coefficient(${\gamma}$) with low energy ..and work function ${\phi}_{\omega}$(${\theta}$ = 0 and ${\theta}$ = 20) of the MgO thin film in AC-PDPs has been measured by ${\gamma}$-FIB system. The MgO thin film has been deposited from sintered material under electron beam evaporation method. The energy of $He^+$ ions used has been ranged from 50eV to 150eV. Oblique ion beam has been chosen to be 10 degree, 20 degree and 30 degree. It is found that the higher secondary electron emission coefficient(${\gamma}$) has been achieved by the higher oblique ion beam up to inclination angle of 30 degree than the perpendicular incident ion beam.

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