• Advances in concrete construction
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• v.9 no.3
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• pp.313-326
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• 2020

Glass fiber-reinforced polymer (GFRP) bars have been introduced as an effective alternative for the conventional steel reinforcement in concrete structures to mitigate the costly consequences of steel corrosion. However, despite the superior performance of these composite materials in terms of corrosion, the effect of replacing steel reinforcement with GFRP on the seismic performance of concrete structures is not fully covered yet. To address some of the key parameters in the seismic behavior of GFRP-reinforced concrete (RC) structures, two full-scale beam-column joints reinforced with GFRP bars and stirrups were constructed and tested under two phases of loading, each simulating a severe ground motion. The objective was to investigate the effect of damage due to earthquakes on the service and ultimate behavior of GFRP-RC moment-resisting frames. The main parameters under investigation were geometrical configuration (interior or exterior beam-column joint) and joint shear stress. The performance of the specimens was measured in terms of lateral load-drift response, energy dissipation, mode of failure and stress distribution. Moreover, the effect of concrete damage due to earthquake loading on the performance of beam-column joints under service loading was investigated and a modified damage index was proposed to quantify the magnitude of damage in GFRP-RC beam-column joints under dynamic loading. Test results indicated that the geometrical configuration significantly affects the level of concrete damage and energy dissipation. Moreover, the level of residual damage in GFRP-RC beam-column joints after undergoing lateral displacements was related to reinforcement ratio of the main beams.

• Maxillofacial Plastic and Reconstructive Surgery
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• v.34 no.3
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• pp.180-185
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• 2012

Purpose: An accurate preoperative analysis of the patient is essential in orthognathic surgery in order to acquire superior results. In profile, the location of the chin's position may change according to the neck's inclination. This may ultimately affect the amount of surgical movement. During acquisition of cephalometric radiographs, or in supine position, there is a discrepancy in the neck's inclination. This means that there are also various discrepancies between the actual profile and the various preoperative profile images. In the clinical situation, the decision in performing genioplasty usually lies in the analysis of the patient's profile on the operating table at the final stages of orthognathic surgery. This study aims to analyze the different preoperative profile images and to compare their discrepancies. Methods: Fifty eight patients undergoing orthognathic surgery were chosen. These patients were divided into three groups according to angle's classification of malocclusion, as class I, II or III. The right profile of these patients in centric occlusion was taken in natural head position (NHP). This was set as the 'actual profile image.' Another right profile image was taken on the operating table after insertion of the nasotracheal intubation and with muscle relaxants in effect. This was also taken in centric occlusion. The angle (denoted 'A') between the soft tissue glabella-pognion and the true vertical plane was found in the above-mentioned profile images and in the cephalometric radiographs. The differences of these values were analyzed. Results: There were differences in Angle 'A' in all of the preoperative images. These values were however, not statistically significant. Conclusion: In order to gain an esthetic profile during orthognathic surgery, the NHP is shown to be the most reliable position. Images reproducing such head positions should be used in the treatment planning process.

• Journal of Oral Medicine and Pain
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• v.14 no.1
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• pp.57-66
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• 1989

66 patients with temporomandibular disorders were selected for experimental group, and 45 normal subjects who were Dental students were selected for control group. Average age of experimental group was 30.5 years, Male to Female ratio was 2 : 3, and their age distribution were teen-ages to seventh decades. Transcranial radiography (TR) with Denar Accurad 100 was used for each group to get the values of width in joint spaces and to investigate the bony changes of articular surfaces and relative condylar position to articular fossa. In addition to TR, clinical interview and routine charting about amount of mandibular movements and occlusal variations were carried out in experimental group. The obtained results were as follows : 1. The mean values of joint space with in control group were 2.15mm to anterior, 2.98mm to superior and 2.29mm to posterior and the value of relative condylar position to the deepest portion of articular fossa was 0.21mm to anterior. In experimental group, those values were 2.01mm, 2.14mm 2.22mm and 0.12mm to posterior in sequence, respectively. Joint spaces in experimental group, therefore, were inclined to decreased, and relative condylar position was inclined to retrude. Joint space in control group showed symmetric condylar position, but in experimental group showed asymmetry. 2. Non-affected joints with no bony changes in experimental group showed the narrowest joint spaces which were thought to manifest the abnormal stress to non-affected side to dysfunctional state of contralateral affected joints. 3. Amount of mandibular movements in experimental group were within normal values in lateral movements and in protrusive movement but in opening movement with or without passive stretch, those were lower than normal values. Frequency of occlusal variation, for example, protrusive posterior contacts, open bite, median line shift to lateral side were inclined to increase with bony changes and with crepitus.

• Journal of Korean Foot and Ankle Society
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• v.13 no.2
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• pp.138-141
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• 2009

Purpose: Regardless of potential and actual complications, the sesamoidectomy either tibial side or fibular side or both, had been used as a surgical option for various pathologic conditions. The objective of this cadaveric study was to identify the changes of range of motion of great toe after sesamoidectomy. Material and Methods: Eight fresh cadaver legs were used. The angular changes of the hallucal articulations were measured by traction of the flexor hallucis longus tendon at the proximal border of fibro-osseous tarsal tunnel and by traction of the extensor hallucis longus tendon at the superior border of inferior extensor retinaculum. The measurement started at neutral position and proceeded to the maximum for respective tendons. After sesamoidectomy either partial or total, same procedures were repeated and the angular changes were measured. Results: In flexion of great toe, there were significant metatarsophalangeal angular differences at 1 cm traction in total sesamoidectomy and lateral sesamoidectomy. In extension of great toe, there were significant metatarsophalangeal angular differences at more than 2 cm traction in total sesamoidectomy. In other measurements, there were no significant angular changes of the hallucal articulations. Conclusion: The sesamoidectomy resulted in change of motion of great toe. Statistical analysis showed that the significant increases in the initial flexion and maximal extension occurred with total sesamoidectomy and the significant increase in the initial flexion occurred with lateral sesamoidectomy.

• Steel and Composite Structures
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• v.17 no.4
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• pp.471-495
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• 2014

The responses of steel buildings with perimeter moment resisting frames (PMRF) with medium size columns (W14) are estimated and compared with those of buildings with deep columns (W27), which are selected according to two criteria: equivalent resistance and equivalent weight. It is shown that buildings with W27 columns have no problems of lateral torsional, local or shear buckling in panel zone. Whether the response is larger for W14 or W27 columns, depends on the level of deformation, the response parameter and the structural modeling under consideration. Modeling buildings as two-dimensional structures result in an overestimation of the response. For multiple response parameters, the W14 columns produce larger responses for elastic behavior. The axial load on columns may be significantly larger for the buildings with W14 columns. The interstory displacements are always larger for W14 columns, particularly for equivalent weight and plane models, implying that using deep columns helps to reduce interstory displacements. This is particularly important for tall buildings where the design is usually controlled by the drift limit state. The interstory shears in interior gravity frames (GF) are significantly reduced when deep columns are used. This helps to counteract the no conservative effect that results in design practice, when lateral seismic loads are not considered in GF of steel buildings with PMRF. Thus, the behavior of steel buildings with deep columns, in general, may be superior to that of buildings with medium columns, using less weight and representing, therefore, a lower cost.

• Journal of Korean Neurosurgical Society
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• v.30 no.12
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• pp.1388-1393
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• 2001

Objective : In the retrospective analyzing 19 consecutive patients with subaxial cervical spine(C3~T1) injury treated by posterior cervical fixation and fusion, clinical manifestation, radiologic finding, operative technique, and postoperative results following 6 months were analyzed. Materials and Methods : Most common fracture level was C4-5, mean age 41, and male to female ratio 13 : 6. The most common cause of injury was motor vehicle accident(17 cases). In 19 cervical procedures, interspinous triple wiring was done in 14 cases, lateral mass plating in 5 cases, and additional anterior fusion in 2 cases. Results : Twelve weeks after operation, all cases were reviewed by plain cervical radiogram. In 17 cases that treated by posterior fusion only, 14 cases(81%) had kyphotic angle change less than $5^{\circ}$, 2 cases(12%) $5-20^{\circ}$, and 1 case(6%) more than $20^{\circ}$. Overall fusion rate was 88%, and there was no significant difference of bone fusion rate between autogenous bone graft and allogenous bone graft. Conclusion : In the case of severe posterior column injury or displacement, posterior approach seems superior to anterior approach, but in the case of combined anterior column injury, anterior approach is considered necessary. In this study, posterior fixation and fusion might be acceptable procedure for subaxial cervical fracture and dislocation, owing to its high fusion rate, low kyphotic angulation and low operation related complication rate.

• Journal of Korean Neurosurgical Society
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• v.40 no.2
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• pp.84-89
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• 2006

Objective : The purpose of this study is to compare the outcomes of two methods for stabilization and fusion : Postero-Lateral Fusion [PLF, pedicle screw fixation with bone graft] and Posterior Lumbar Interbody Fusion [PLIF, cage insertion] for spinal stenosis and recurred disc herniation except degenerative spondylolisthesis. Methods : Seventy one patients who underwent PLF [n=36] or PLIF [n=35] between 1997 and 2001 were evaluated prospectively. These two groups were compared for the change of interbody space, the range of segmental angle, the angle of lumbar motion, and clinical outcomes by Prolo scale. Results : The mean follow-up period was 32.6 months. The PLIF group showed statistically significant increase of the interbody space after surgery. However, the difference in the change of interbody space between two groups was insignificant [P value=0.05]. The range of segmental angle was better in the PLIF group, but the difference in the change of segmental angle was not statistically significant [P value=0.0l7]. Angle of lumbar motion was similar in the two groups. Changes of Prolo economic scale were not statistically significant [P value=0.193]. The PLIF group showed statistically significant improvement in Prolo functional scale [P value=0.003]. In Prolo economic and functional scale, there were statistically significant relationships between follow-up duration [P value<0.001]. change of interbody space [P value<0.001], and range of segmental angle [P value<0.001]. Conclusion : Results of this study indicate that PLIF is superior to PLF in interbody space augmentation and clinical outcomes by Prolo functional scale. Analysis of clinical outcomes showed significant relationships among various factors [fusion type, follow-up duration, change of interbody space, and range of segmental angle]. Therefore, the authors recommend instrumented PLIF to offer better clinical outcomes in patients who needed instrumented lumbar fusion for spinal stenosis and recurred disc herniation.

• Journal of Korean Neurosurgical Society
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• v.45 no.3
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• pp.169-175
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• 2009

Objective : The goal of this study was to evaluate the biomechanical features of human cadaveric spines implanted with the Activ L prosthesis. Methods : Five cadaveric human lumbosacral spines (L2-S2) were tested for different motion modes, i.e. extension and flexion, right and left lateral bending and rotation. Baseline measurements of the range of motion (ROM), disc pressure (DP), and facet strain (FS) were performed in six modes of motion by applying loads up to 8 Nm, with a loading rate of 0.3 Nm/second. A constant 400 N axial follower preload was applied throughout the loading. After the Activ L was implanted at the L4-L5 disc space, measurements were repeated in the same manner. Results : The Activ L arthroplasty showed statistically significant decrease of ROM during rotation, increase of ROM during flexion and lateral bending at the operative segment and increase of ROM at the inferior segment during flexion. The DP of the superior disc of the operative site was comparable to those of intact spine and the DP of the inferior disc decreased in all motion modes, but these were not statistically significant. For FS, statistically significant decrease was detected at the operative facet during flexion and at the inferior facet during rotation. Conclusion : In vitro physiologic preload setting, the Activ L arthroplasty showed less restoration of ROM at the operative and adjacent levels as compared with intact spine. However, results of this study revealed that there are several possible theoretical useful results to reduce the incidence of adjacent segment disease.

• Journal of Korean Neurosurgical Society
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• v.29 no.12
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• pp.1650-1656
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• 2000

Objective : Little consensus exists concerning which temporal lobe structures need to be resected or how much resection should be done during hippocampal resection. The purpose of this study is to identify whether the extent of hippocampal resection influences seizure after anterior temporal lobectomy. Materials and Methods : The extent of hippocampal resection was assessed in 96 patients who underwent temporal lobectomy for medically intractable complex partial seizures originating from a unilateral seizure focus in the anteromesial temporal lobe. Patients who had structural lesion were excluded from the study. Postoperative magnetic resonance imaging in the coronal and saggital planes were used to quantify the extent of the hippocampal and lateral cortical resection. The patients were divided into two groups. Patients who underwent hippocampal resection to the level of the cerebral peduncle were included in the partial resection group, and those who had resection to the level of the colliculus were assigned to total resection group. Seizure outcomes were defined according to the Engel classification and compared between the two groups. Neuropsychologic outcomes in the selected cases were reviewed. Results : The over-all seizure-free outcome(Engel classification 1) was accomplished in 75%(72/96) of the patients (mean duration of follow-up, 36.8 months). The total hippocampectomy group had a statistically superior seizure outcome than the partial hippocampectomy group(87.3% versus 58.5% seizure-free, p-value=0.001). Also, younger patients had a more favorable outcome. Other variables such as laterality, the extent of lateral cortical resection, age at onset and gender were not significant. The pre- and postoperative memory functions were evaluated in 24 patients. A worse postoperative memory outcome was associated with partial hippocampectomy. However this was not acceptable due to a former bias. Conclusion : The result of this study conforms that aggressive hippocampectomy resulted in a better seizure outcome.

• Imaging Science in Dentistry
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• v.37 no.1
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• pp.15-18
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• 2007

Purpose : Disc and condylar position were observed on MRIs of temporomandibular joint disorder patients and condylar position agreement between MRI and tranascranal radiography was evaluated. Materials and Methods MRI and transcranial radiographs of both TM joints from 67 patients with temporemandibular disorder were used. On MRI, the position and shape of disc and condylar position as anterior, middle, posterior was evaluated at medial, center, and lateral views. On transcranial radiographs, condylar position was evaluated using the shortest distance from condyle to fossa in anterior, superior, and posterior directions. Results. 1. On MRI, 96 joints (71.6%) of 134 had anterior disc dispalcement with reduction and 38 joints (28.4%) without reduction. 2. Fourteen (14.6%) of 96 reducible joints showed anterior condylar position, 19 (19.8%) showed central position, 63 joints (65.6%) showed posterior position. Two joints (5.3%) of 38 non-reducible joints showed anterior condylar position, while 9 (23.7%) showed central position, and 27 (71.1%)-posterior position. 3. In 85 joints (63.4%) of 134, the transcranial condylar position agreed with that of the central MRI view, 10 joints (7.5%) with that of medial, 16 joints (11.9%) with that of lateral, and 23 joints (17.2%) disagreed with that of MRI. Conclusion : On MRT, most oi the reducible and non-reducible joints showed posterior condylar position. Transcranial radiographs taken with machine designed for TMJ had better agreement of condylar position with that of MRI. Extremely narrow joint spaces or very posterior condylar positions observed on transcranial radiographs had a little more than fifty percent agreement with those of MRIs.