• Journal of the Korean Society for Precision Engineering
• /
• v.25 no.11
• /
• pp.107-118
• /
• 2008

In this study, lower extremity joint kinematics and kinetics and lumbar lordosis were investigated for two different symmetrical lifting techniques(squat and stoop) using the three-dimensional motion analysis. Twenty-six male volunteers lifted boxes weighing 5, 10 and 15kg by both squat and stoop lifting techniques. There were not significant differences in maximum lumbar joint moments between the two techniques. The hip and ankle contributed the most part of the support moments during squat lifting, and the knee flexion moment played an important role in stoop lifting. The hip, ankle and lumbar joints generated power and only the khee joint absorbed power in the squat lifting. The knee and ankle joints absorbed power, the hip and lumbar joints generated power in the stoop lifting. The bi-articular antagonist muscles' co-contraction around the knee joint during the squat lifting and the eccentric co-contraction of the gastrocnemius and semitendinosus were found to be important for straightening up during the stoop lifting. At the time of lordotic curvature appearance in the squat lifting, there were significant correlations in all three lower extremity joint moments with the lumbar joint. Differently, only the hip moment had significant correlation with the lumbar joint in the stoop lifting. In conclusion, the knee extension which is prominent kinematics during the squat tilling was produced by the contributions of the kinetic factors from the hip and ankle joints(extensor moment and power generation) and the lumbar extension which is prominent kinematics during the stoop lifting could be produced by the contributions of the knee joint kinetic factors(flexor moment, power absorption, bi-articular muscle function).

• Korean Journal of Veterinary Research
• /
• v.39 no.1
• /
• pp.169-176
• /
• 1999

The purposes of this study were to set up the method of the natural killer(NK) cell activity assay using the flow cytometer and to examine the characteristics and distribution of the NK cell during rat hepatocarcinogenesis. Forty five male 6 week-old specific pathogen free(SPF) Sprague-Dawley rats were randomly divided into three groups. Group I was the non-treated control and given normal diet and water. Group II was treated with diethylnitrosamine(DEN, 200mg/kg, i.p.) and partial hepatectomy. Group III was treated with DEN, partial hepatectomy and 0.05% phenobarbital sodium in water from 3 to 16 weeks. All animals were examined the morphology of the large granular lymphocyte(LGL), the LGL percent of the total lymphocytes and the LGL conjugation rate with YAC-1 cell in peripheral blood, spleen and liver. Moreover, activity of the LGL isolated from peripheral blood lymphocytes was determined using the flow cytometer. As results, LGL were observed in the peripheral blood, spleen and liver. LGL were observed the relatively faintly staining basophilic cytoplasm with granules, and eccentric, often kidney-shaped nuclei in Giemsa stain. Its size was $11{\sim}13{\mu}m$. LGL percentage of the isolated lymphocytes in peripheral blood, spleen and liver were 1.8~2.3%, 1.3~1.4% and 0.87~0.99%, respectively. LGL conjugation rate with YAC-1 cell was shown to be peripheral blood(9.3~10.3 %) > spleen(7.7~8.7%) > liver(5.6~7.0%). The activity of the LGL isolated from peripheral blood lymphocytes in Group I, II and III was 33.7%, 30.5% and 35.4%, respectively. However, all values were not significantly between groups.

• The Korean Journal of Cytopathology
• /
• v.2 no.2
• /
• pp.153-159
• /
• 1991

Langerhans' cell histiocytosis (LCH), known for histiocytosis X, is a clinicopathologic entity characterized by proliferation of Langerhans' cells (LCs) throughout the body including the reticuloendothelial system, bone, and skin. LCs is currently considered as a distinct type of histlocytic cells, not primarily phagocytic in nature. Recently, we could make the diagnosis on cytologic specimen in a 3 month-old-boy and a 3 year-old-boy. The cases were diagnosed on scraping smear from the skin and fine needle aspiration cytology from the lymph node, respectively. The characteristic cytologic features of Langerhans' cells were noted in the nuclei, namely eccentric, indented, elongated, and grooved nuclei. The cells also had abundant and acidophilic cytoplasm. The cytologic diagnoses were confirmed on the biopsies from the skin and lymph node, respectively.

• Journal of the Korea Concrete Institute
• /
• v.15 no.3
• /
• pp.482-493
• /
• 2003

Flat plate structures subjected to lateral load have less deformability than conventional moment frames, due to the brittle failure of plate-column connection. In the present study, parametric study using nonlinear finite element analysis was performed to investigate the deformability of flat plates. The numerical results show that as number of continuous spans increases, the deformability of flat plates considerably decreases. Therefore, existing experiments using sub-assemblages with 1 or 2 spans may overestimate the deformability of flat plates, and current design provisions based on the experiments may not be accurate in estimating the deformability. A design method estimating the deformability was developed on the basis of numerical results, and verified by comparison with existing experiment. In the proposed method, the effects of primary design parameters such as direct shear force, punching shear capacity, aspect ratio of connection, number of spans, and initial stiffness of plate can be considered.

• Smart Structures and Systems
• /
• v.26 no.3
• /
• pp.373-390
• /
• 2020

Hybrid simulation (HS) is a versatile tool for structural performance evaluation under dynamic loads. Although real structural responses are often multiple-directional owing to an eccentric mass/stiffness of the structure and/or excitations not along structural major axes, few HS in this field takes into account structural responses in multiple directions. Multi-directional loading is more challenging than uni-directional loading as there is a nonlinear transformation between actuator and specimen coordinate systems, increasing the difficulty of suppressing loading error. Moreover, redundant actuators may exist in multi-directional hybrid simulations of large-scale structures, which requires the loading strategy to contain ineffective loading of multiple actuators. To address these issues, lately a new strategy was conceived for accurate reproduction of desired displacements in bi-directional hybrid simulations (BHS), which is characterized in two features, i.e., iterative displacement command updating based on the Jacobian matrix considering nonlinear geometric relationships, and force-based control for compensating ineffective forces of redundant actuators. This paper performs performance validation and application of this new mixed loading strategy. In particular, virtual BHS considering linear and nonlinear specimen models, and the diversity of actuator properties were carried out. A validation test was implemented with a steel frame specimen. A real application of this strategy to BHS on a full-scale 2-story frame specimen was performed. Studies showed that this strategy exhibited excellent tracking performance for the measured displacements of the control point and remarkable compensation for ineffective forces of the redundant actuator. This strategy was demonstrated to be capable of accurately and effectively reproducing the desired displacements in large-scale BHS.

• Journal of Korean Dental Science
• /
• v.5 no.1
• /
• pp.29-36
• /
• 2012

Purpose: To investigate the effects of anterior guidance (AG) change on the working (WCP) and non-working condylar paths (NWCP), and lower incisor path (LIP) using a splint with flat (FAG) or steep AG (SAG). Materials and Methods: The samples consisted of six young adult women (mean age=$23.5{\pm}3.3$ years). Inclusion criteria were skeletal Class I and normodivergent pattern, normal overbite/overjet, minimal slide from retruded cuspal position to intercuspal position, no temporomandibular disorder signs and symptoms, mutually protected occlusion, and minimal tooth wear. After the values of natural AG (NAG) were obtained as a reference for each patient, two types of splints ($15^{\circ}$ flatter and steeper than NAG) were made. After insertion of the splints with FAG or SAG, the WCP, NWCP, and LIP were recorded five times for each patient using an ultrasonic AQR (SAM, Munich, Germany) and statistical analysis was subsequently performed. Result: NAG exhibited postero-superior movement in the WCP and did not show a noticeable immediate side shift (ISS) or difference between the eccentric (EP) and returning paths (RP) in the NWCP. FAG was associated with an irregular and excessive WCP, an increase in ISS, and a difference between EP and RP in the NWCP. SAG showed minimal WCP movement and a decrease in the extent of difference between EP and RP in the NWCP. LIP showed significant differences in EP and in RP (P<0.001, all; FAG

• Journal of Korean Society of Steel Construction
• /
• v.23 no.2
• /
• pp.249-259
• /
• 2011

In this study, the distortional behaviors of tub-section steel girders subjected to torsional loading were analyzed, and predictor equations were developed for estimating the member forces induced in the internal bracing system installed in the steel tub girders. Torsional loadings originated either by eccentric vertical loading or girder curvature were decomposed into the pure torsional force component that does not affect the distortional box deformation, and into the distortional force component that directly induces box distortion. The axial member forces induced in the internal cross frames were formulated as a function of the magnitude of torsional loading through the analytical investigation of the interactions between the distortional force component and internal cross frames. To verify the proposed equations, three-dimensional finite element analysis (3D FEA) was conducted for the straight simple-span girder and the three-span continuous girder samples. Very good agreement was found between the member forces from the FEA and the proposed equations.

• Archives of Plastic Surgery
• /
• v.38 no.4
• /
• pp.494-497
• /
• 2011

Purpose: Schwannoma, a benign peripheral nerve tumor, is slow-growing, encapsulated neoplasm that originates from the Schwann cell of the nerve sheath. Schwannoma most frequently involves the major nerve. Schwannoma occurring in the superficial radial nerve rare. This is a report of our experience with schwannoma arising from the superficial radial nerve with neurologic symptom. Methods: A 55-year-old woman presented with eight-month history of progressive numbness and paresthesia in dorsum of the thumb and index finger. Physical examination revealed a localized mass on the midforearm. Sonographic examination showed an ovoid, heterogenous, hypoechoic lesion, located eccentrically in related to the superficial radial nerve. The lesion was mobile in the transverse but not in the longitudinal axis of the nerve, which was thought to favour schwannoma rather than neurofibroma. At operation, a $20{\times}15mm$ ovoid, yellowish grey mass was seen arising from the superficial radial nerve. The tumor present as eccentric masses over which the nerve fibers are splayed. Using operating microscope, the tumor was removed, preserving the surrounding nerve. Results: Histology confirmed that the mass was a benign schwannoma. There were no postoperative complications. After two months the patient had no clinically demonstrable sensory deficit. Conclusion: An unsusual case of a schwannoma of the superficial radial nerve is presented. In case with neurologic symptom, prompt surgical decompression must be made to prevent further nerve damage and to restore nerve function early.

• Clinics in Shoulder and Elbow
• /
• v.26 no.1
• /
• pp.93-106
• /
• 2023

Reverse total shoulder arthroplasty (RTSA) emerged as a new concept of arthroplasty that does not restore normal anatomy but does restore function. It enables the function of the torn rotator cuff to be performed by the deltoid and shows encouraging clinical outcomes. Since its introduction, various modifications have been designed to improve the outcome of the RTSA. From the original cemented baseplate with peg or keel, a cementless baseplate was designed that could be fixed with central and peripheral screws. In addition, a modular-type glenoid component enabled easier revision options. For the humeral component, the initial design was an inlay type of long stem with cemented fixation. However, loss of bone stock from the cemented stem hindered revision surgery. Therefore, a cementless design was introduced with a firm metaphyseal fixation. Furthermore, to prevent complications such as scapular notching, the concept of lateralization emerged. Lateralization helped to maintain normal shoulder contour and better rotator cuff function for improved external/internal rotation power, but excessive lateralization yielded problems such as subacromial notching. Therefore, for patients with pseudoparalysis or with risk of subacromial notching, a medial eccentric tray option can be used for distalization and reduced lateralization of the center of rotation. In summary, it is important that surgeons understand the characteristics of each implant in the various options for RTSA. Furthermore, through preoperative evaluation of patients, surgeons can choose the implant option that will lead to the best outcomes after RTSA.

• Steel and Composite Structures
• /
• v.47 no.1
• /
• pp.51-69
• /
• 2023

In tied-arch bridges, a properly designed connection between the arch and the deck may become crucial, since the forces in the structure may be significantly reduced. This implies substantial material savings and, consequently, cheaper constructions. The introduction of the Nielsen cable arrangement (composed of V-shaped inclined hangers) in the last century was a milestone because it was able to reduce deflections and bending moments both in the arch and in the deck. So far, the Nielsen cable arrangement has proven to be successful in traditional vertical arch bridges. However, despite its advantages, it has not been widely applied to spatial arch bridges. Thus, this article analyses the difference between the structural behavior of spatial arch bridges with Nielsen-type cable arrangements with respect to those with classical vertical hanger configurations. The main goal is to verify whether the known effectiveness of the Nielsen cable arrangement for classical arch bridges is still preserved when applied to spatial arch bridges. In order to achieve this objective, and as the first part of our study, a set of different all-steel bridges composed of vertical and inclined arches with straight decks have been compared for both cable arrangements. As a major conclusion, for planar vertical arch bridges, the Nielsen-type cable arrangement is always the most effective. In addition, it also seems that, for spatial arch bridges composed of a straight deck and an inclined arch, it still keeps most of its effectiveness as long as the arch is moderately inclined.