• Wind and Structures
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• 제6권1호
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• pp.23-40
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• 2003

The steady state response of a torsionally coupled system with tuned mass dampers (TMDs) to external wind-induced harmonic excitation is presented. The torsionally coupled system is considered as one-way eccentric system. The eccentricity considered in the system is accidental eccentricity only. The performance of single tuned mass damper (TMD) optimally designed without considering the torsion is investigated for the torsionally coupled system and found that the effectiveness of a single TMD is significantly reduced due to torsion in the system. However, the design of TMD system without considering the torsion is only justified for torsionally stiff systems. Further, the optimum parameters of a single TMD considering the accidental eccentricity are obtained using numerical searching technique for different values of uncoupled torsional to lateral frequency ratio and aspect ratio of the system. The optimally designed single TMD system is found to be less effective for torsionally coupled system in comparison to uncoupled system. This is due to the fact that a torsionally coupled system has two natural frequencies of vibration, as a result, at least two TMDs are required which can control both lateral and torsional response of the system. The optimum damper parameters of different alternate arrangements such as (i) two identical TMDs placed at opposite corners, (ii) two independent TMDs and (iii) four TMDs are evaluated for minimum response of the system. The comparative performance of the above TMDs arrangements is also studied for both torsionally coupled and uncoupled systems. It is found that four TMDs arrangement is quite effective solution for vibration control of torsionally coupled system.

• 한국임상수의학회지
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• 제37권1호
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• pp.34-37
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• 2020

A 1-year-old castrated male Shih-Tzu dog presented with severe orbital swelling involving the right eye. Physical examination identified a painless swelling of the right periocular tissues and protrusion of the third eyelid. Radiographic examination revealed a well-delineated, spherical (3 × 3 cm) soft tissue mass. Ultrasonography confirmed a hypoechoic, multilobular, tubular cystic structure with hyperechoic foci. Fine needle aspiration was conducted and the cytologic impression revealed copious mucus, increased neutrophilic leucocytes, and foamy macrophages. Th tentative diagnosis was zygomatic sialocele, and the lesion was resected through lateral orbitotomy. Surgical exploration identified a multilobular mass adhering to the zygomatic glands. Both the zygomatic gland and the mass were removed. Histological findings were consistent with those of an inflamed myxoma. No postoperative recurrence occurred within 1 year.

• Structural Engineering and Mechanics
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• 제77권6호
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• pp.721-734
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• 2021

The seismic analysis of structures without applying the effects of soil can undermine functional objectives of structure so that it can affect all the desired purposes at the design and control stages of the structure. In this research, employing OpenSees and MATLAB software simultaneously and developing a definite three-dimensional finite element model of a high-rise concrete structure, designed using performance-based plastic design approach, the performance of Tuned Mass Damper (TMD) and Active Mass Damper (AMD) is both examined and compared. Moreover some less noted aspects such as nonlinear interaction of soil and structure, uplift, nonlinear behavior of structure and structural torsion have received more attention. For this purpose, the analysis of time history on the structural model has been performed under 22 far-field accelerogram records. Examining a full range of all structural seismic responses, including lateral displacement, acceleration, inter-story drift, lost plastic energy, number of plastic hinges, story shear force and uplift. The results indicate that TMD performs better than AMD except for lateral displacement and inter-story drift to control other structural responses. Because on the one hand, nonlinear structural parameters and soil-structure interaction have been added and on the other hand, the restriction on the control force applied that leads up to saturation phenomenon in the active control system affect the performance of AMD. Moreover, the control force applied by structural control system has created undesirable acceleration and shear force in the structure.

• 한국임상수의학회지
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• 제38권2호
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• pp.85-88
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• 2021

A 9-year-old, intact female Shih-tzu dog presented with a three-week history of anorexia, lethargy, and weight loss. Abdominal radiography revealed a mass in the right cranial quadrant of the abdomen that was displacing the right kidney caudally. Ultrasonography showed a large, irregular, heterogeneous hepatic mass and a small amount of peritoneal fluid. On computed tomography (CT), a large hypoattenuating mass with heterogeneous contrast enhancement occupied the right lateral lobe, and parts of the right medial and caudate lobes of the liver. There was no evidence of regional lymph node or pulmonary metastasis. Lobectomy of the right medial, right lateral and caudate liver lobes was performed, however, the patient did not recover from surgery. Hepatoblastoma was confirmed by histological examination. Hepatoblastoma is rare in dogs, and this is the first report describing CT imaging of hepatoblastoma in a dog.

• Journal of Korean Neurosurgical Society
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• 제30권3호
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• pp.366-370
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• 2001

Objective : The authors present three cases of brain tumors in which epidural hematomas(EDHs) were developed postoperatively in the remote areas from craniotomy sites. The preventive tactics as well as possible mechanisms of development of remote EDH are discussed. Material and Methods : The magnetic resonance imagings of three patients revealed a left lateral ventricular mass located just aside of foramen Monro in a 27-year-old male, a large cystic mass in the temporal lobe in a 35-year-old male, and a partially calcified pineal mass in a 27-year-old male patient. The surgical removals of these tumors were performed without any noticeable events during surgery via left frontal transcortical transventricular approach for lateral ventricular tumor, left temporal craniotomy for cystic temporal tumor, and right occipital transtentorial approach for pineal tumor. Results : Postoperative EDHs remote from the sites of craniotomy were detected by the immediate postoperative computerized tomographic scans. We obtained good outcomes without any morbidity in all three patients with emergent evacuation of the hematoma. The pathologic diagnoses were lateral ventricular ependymoastrocytoma, temporal craniopharyngioma and mixed germinoma of the pineal region. Conclusion : It is postulated that a sudden reduction of intracranial pressure(ICP) at the time of tumor removal may strip the dura from the inner table of the skull to cause EDH from the remote site of craniotomy. Gradual reduction of ICP with slow drainage of cerebrospinal fluid before tumor removal as well as lowering the head position of patient during surgery might be helpful for preventing this unusual complication.

• Journal of Korean Neurosurgical Society
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• 제57권6호
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• pp.460-464
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• 2015

Objective : Bilateral C1 lateral mass and C2 pedicle screw fixation (C1LM-C2P) is an ideal technique for correcting atlantoaxial instability (AAI). However, the inevitable situation of vertebral artery injury or unfavorable bone structure may necessitate the use of unilateral C1LM-C2P. This study compares the fusion rates of the C1 lateral mass and C2 pedicle screw in the unilateral and bilateral methods. Methods : Over five years, C1LM-C2P was performed in 25 patients with AAI in our institute. Preoperative studies including cervical X-ray, three-dimensional computed tomography (CT), CT angiogram, and magnetic resonance imaging were performed. To evaluate bony fusion, measurements of the atlanto-dental interval (ADI) and CT scans were performed in the preoperative period, immediate postoperative period, and postoperatively at 1, 3, 6, and 12 months. Results : Unilateral C1LM-C2P was performed in 11 patients (44%). The need to perform unilateral C1LM-C2P was due to anomalous course of the vertebral artery in eight patients (73%) and severe degenerative arthritis in three patients (27%). The mean ADI in the bilateral group was 2.09 mm in the immediate postoperative period and 1.75 mm in 12-months postoperatively. The mean ADI in the unilateral group was 1.82 mm in the immediate postoperative period and 1.91 mm in 12-months postoperatively. Comparison of ADI measurements showed no significant differences in either group (p=0.893), and the fusion rate was 100% in both groups. Conclusion : Although bilateral C1LM-C2P is effective for AAI from a biomechanical perspective, unilateral screw fixation is a useful alternative in patients with anatomical variations.

• Structural Engineering and Mechanics
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• 제52권1호
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• pp.51-73
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• 2014

A three-dimensional finite element model for the Jiashao Bridge, the longest multi-span cable-stayed bridge in the world, is established using the commercial software package ANSYS. Dynamic characteristics of the bridge are analyzed and the effects of structural system measures including the rigid hinge, auxiliary piers and longitudinal constraints between the girders and side towers on the dynamic properties including modal frequency, mode shape and effective mass are studied by referring to the Jiashao Bridge. The analysis results reveal that: (i) the installation of the rigid hinge significantly reduces the modal frequency of the first symmetric lateral bending mode of bridge deck. Moreover, the rigid hinge significantly changes the mode shape and effective mass of the first symmetric torsional mode of bridge deck; (ii) the layout of the auxiliary piers in the side-spans has a limited effect on changing the modal frequencies, mode shapes and effective masses of global vibration modes; (iii) the employment of the longitudinal constraints significantly increases the modal frequencies of the vertical bending modes and lateral bending modes of bridge deck and have significant effects on changing the mode shapes of vertical bending modes and lateral bending modes of bridge deck. Moreover, the effective mass of the first anti-symmetric vertical bending of bridge deck in the longitudinal direction of the fully floating system is significantly larger than that of the partially constrained system and fully constrained system. The results obtained indicate that the structural system measures of the multi-span cable-stayed bridge have a great effect on the dynamic properties, which deserves special attention for seismic design and wind-resistant design of the multi-span cable-stayed bridge.

• Annals of Clinical Neurophysiology
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• 제8권2호
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• pp.152-157
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• 2006

Background: Meralgia paresthesia (MP) is characterized by sensory impairment in the anterolateral aspect of the thigh and usually caused by a lateral femoral cutaneous nerve (LFCN) lesion. It is well known that several physiologic factors including age, obesity, and sex can affect nerve conduction. This study aimed to determine whether body mass index (BMI) and age can influence on the conduction velocity and action potential amplitude of the LFCN. Methods: Fifty six individuals without any previous neuromuscular disease participated in this study. LFCN was studied orthodromically, distally from the anterior superior iliac spine. The values, such as sensory nerve action potential (SNAP) amplitude and sensory nerve conduction velocity (NCV) were obtained. SNAP of the LFCN were formed on both sides in forty three individuals. Results: No difference of demographic factors was observed between two groups divided according to the presence of SNAP formation. BMI had a significant relationship with SNAP amplitude and NCV of the LFCN. Moreover, Multiple regression analyses of nerve conduction values showed the significant correlation of body mass index and age with nerve conduction velocity. Conclusions: We may suggest that nerve conduction of the LFCN can be affected by age and BMI. Further study to obtain normal nerve conduction data and compare these data with those of meralgia paresthetica patients should be continued.

• Neurospine
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• 제15권4호
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• pp.362-367
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• 2018

Objective: To assess the efficacy of cervical open-door laminoplasty by hydroxyapatite implant insertion between the lamina and the lateral mass without suturing. Methods: All patients who underwent cervical open-door laminoplasty with C2/C7 undermining and insertion of hydroxyapatite implants from C3 to C6 were retrospectively evaluated for surgical time and neurological outcomes according to the Japanese Orthopaedic Association (JOA) score. To assess the alignment of the cervical spine and postoperative cervical pain, the C2-7 angle and a visual analogue scale score were used, respectively. Results: The population consisted of 102 women and 222 men ranging in age from 32 to 90 years. The average surgical time was 86 minutes. Fourteen of 1,296 hydroxyapatite implants were kept in place with sutures due to a weak restoration force of the hinge during surgery. No hydroxyapatite implant dislocation was detected on cervical computed tomography at 1 year after surgery. The average JOA score was $10.2{\pm}2.5$ before surgery and $14.6{\pm}2.8$ at 1 year after surgery. The average recovery rate was 61.8%. The average C2-7 angle at the neutral position was $7.1^{\circ}{\pm}6.2^{\circ}$ before surgery and $6.5^{\circ}{\pm}6.3^{\circ}$ at 1 year after surgery. Conclusion: This method enabled us to achieve minimal exposure of the lateral mass, prevention of lateral mass injury and dural injury, and a shorter surgical time while maintaining acceptable surgical outcomes. The idea that firm suture fixation is needed to prevent spacer deviation during cervical open-door laminoplasty may need to be revisited.

• Journal of the Korean Association of Oral and Maxillofacial Surgeons
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• 제45권3호
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• pp.129-134
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• 2019

Objectives: The objective of this study was to highlight the role of lateral arthroplasty along with interposition of the buccal fat pad (BFP) in the management of Sawhney type III temporomandibular joint (TMJ) ankylosis. Materials and Methods: Ten patients with TMJ ankylosis (7 unilateral and 3 bilateral, total of 13 joints) were treated with lateral arthroplasty and BFP interposition. The bony bridge of the ankylotic mass on the lateral aspect was resected, leaving a distance of 1.5 to 2.0 cm from the base of the skull to the neck of the condyle. The condyle was left intact. Coronoidectomy was performed on the ipsilateral side via the same approach in all cases. The inter-incisal opening was measured at that time, and if it was less than 35 mm, contralateral coronoidectomy was performed by using the intra-oral approach. After satisfactory inter-incisal mouth opening (${\geq}35mm$) was achieved, the TMJ surgical site was revisited, and BFP was retrieved and used to cover the lateral aspect of the medially placed condyle. Results: With lateral arthroplasty, the medially displaced condyle can be left in-situ to maintain the mandibular ramal height and function and to act as a growth center in children. Interposition of the BFP prevents reformation of the lateral bony bridge that was removed. Conclusion: Lateral arthroplasty along with interpositioning of the BFP is a novel technique for managing Sawhney type III ankylosis that achieves management goals while avoiding complex and advanced reconstructive surgical procedures.