• Journal of the Korean Society of Visualization
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• v.21 no.1
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• pp.80-93
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• 2023

We performed numerical simulations of blood flow in an arterial cerebral artery aneurysm to investigate the hemodynamic behavior after coil embolization. A patient-specific model was created based on CTA data. We also conducted the coil embolization simulation to obtain the coil placement within the aneurysm. Blood was assumed to be an incompressible Newtonian fluid, and both the vessel and coil were considered rigid walls. The pulsatile boundary condition was applied at the inlet, and the outflow boundary conditions were used at the outlets. Our findings demonstrated that the coil embolization significantly reduces the blood volume flowrate entering the aneurysm by effectively blocking the inflow jet, leading to a decrease in both TAWSS and WSS, especially at the systolic peak in the impingement zone. While several high OSI regions disappeared over the aneurysm surface, we observed high OSI regions with a relatively small area where the coil did not completely occlude the aneurysm. Overall, these results quantitatively analyzed the effectiveness of coil embolization by focusing on hemodynamic indicators, potentially preventing aneurysm rupture. The present work could contribute to the development of patient-specific coil embolization.

• Journal of Korean Neurosurgical Society
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• v.67 no.1
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• pp.6-13
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• 2024

The integrity of the high cervical spine, the transition zone from the brainstem to the spinal cord, is crucial for survival and daily life. The region protects the enclosed neurovascular structure and allows a substantial portion of the head motion. Injuries of the high cervical spine are frequent, and the fractures of the C2 vertebra account for approximately 17-25% of acute cervical fractures. We review the two major types of C2 vertebral fractures, odontoid fracture and Hangman's fracture. For both types of fractures, favorable outcomes could be obtained if the delicately selected conservative treatment is performed. In odontoid fractures, as the most common fracture on the C2 vertebrae, anterior screw fixation is considered first for type II fractures, and C1-2 fusion is suggested when nonunion is a concern or occurs. Hangman's fractures are the second most common fracture. Many stable extension type I and II fractures can be treated with external immobilization, whereas the predominant flexion type IIA and III fractures require surgical stabilization. No result proves that either anterior or posterior surgery is superior, and the surgeon should decide on the surgical method after careful consideration according to each clinical situation. This review will briefly describe the basic principles and current treatment concepts of C2 fractures.

• Journal of Korean Academy of Oral and Maxillofacial Radiology
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• v.21 no.2
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• pp.165-179
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• 1991

This study was performed to understand the irradiation effects on the mandibular condyle and mandibular growth in developing white rats. Forty eight white male rats of the Sprague-Dawley strain aged 4 weeks, were devided into two groups; control group and experimental group. A single target dose of l0Gy of radiation was given to the mandibular condylar area and the observations of the photo analysis, radiologic, histopathologic and immunohistochemical study revealed as follows; 1. Animals killed one week after irradiation showed lesser increase in body weights, no difference in photo analysis and decreased thickness of cartilagenous layers of the condyle than the control group. 2. Two weeks after irradiation the weight increases were almost same in both irradiated and control groups and in photo analysis, the distance from Mental Foramen to Incisal tip (Mf-It) was longer than the controls. Repair processes were taken place in irradiated group, but the cartilagenous layers were thinner than the controls. 3. By the third week after exposure further repair was seen in the trabeculae and the distance from Condylion to Mandibular plane (Cd-Cd') was longer than the controls and the weight increases were almost same as the controls. 4. At 4 weeks after irradiation the cells of proliferating zone repaired to almost normal findings, but the cartilagenous cell layers were still thinner than the control animals. In photo analysis, the distances from Menton to Anterior Notch (Me-An), from First Molar to Mandibular plane (Fm-Fm') were shorter and the weight increases were lesser than the controls. 5. In the S-100 antibody, the positive cells were increased in number, but decreased reactivities were seen at the proliferating zone of the irradiated groups. In the Monoclonal Anti-Proteoglycan antibody and Type Ⅰ collagen antibody, the irradiated groups showed little decreased number of positive cells and in the Type Ⅱ collagen antibody, the differences between irradiated and control groups were undetectable in immunohistochemical study.

• Journal of Biomedical Engineering Research
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• v.28 no.5
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• pp.628-635
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• 2007

We studied the effect of vibratory stimulations of different leg muscles, tibialis anterior(TA) and triceps surae(TS), and plantar zones in ten healthy subjects during 1) quiet standing, 2) forward lean of body, 3) backward lean of body, 4) right lean of body, and 5) left lean of body. The experiments were performed on the force platform. The effect of vibration were measured by monitoring the area of COP(Center of pressure) sway. The subjects wore a vibratory stimulation system on foot and ankles and were given the instruction not to resist against the applied perturbations. The results show that all vibratory stimulations to lower limb muscles and plantar zones reduced the COP sway area. This reduction of the COP sway area occurred also in partial vibratory stimulations during quiet standing. In forward lean of body, vibratory stimulations to TA reduced the COP sway area. During backward lean of body, vibratory stimulations to TS reduced the COP sway area. When the subject was tilted right, vibratory stimulations to left plantar zone reduced the COP sway area. During left lean of body, vibratory stimulations to right plantar zone reduced the COP sway area. Thus, the influence of vibratory stimulations to leg muscle and plantar zones differed significantly depending on the lean of body. We suggest that the vibration stimuli from leg muscles and plantar zones could be selectively used to help maintaining postural balance stable.

• Journal of Periodontal and Implant Science
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• v.35 no.2
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• pp.359-369
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• 2005

It has been suggested that morphologic characteristics of the periodontium are partly related to the shape and form of the teeth. Furthermore, the severity of symptoms of periodontal disease have been proposed to differ among these various morphologic entities or "biotypes". The purpose of the present study was to examine the relationship between the form of the crowns in the maxillary anterior tooth segment and (1) a group of morphological characteristics and (2) the thickness of the gingiva. The thickness of gingiva was measured by ultrasonic device(SDM). 100 subjects devoid of symptoms of destructive periodontal disease were examined regarding, e.g., probing depth, gingival recession, width of keratinized gingiva, thickness of the keratinized gingiva. From maxillary study cast, the width(at the apical third-CW) and the length(CL) of the crowns of the 6 anterior teeth were determined. A CW/CL-ratio was calculated for each tooth and averaged for each tooth region. The individual mean CW/CL-ratio values for the central incisors were ranked. The 10 subjects ranked highest and the 10 ranked lowest were selected as having either a long-narrow(group N) or a short-wide(group W) form of the crown of the tooth. The data for each of the examined parameters were averaged for each tooth region in each subject and mean values for subjects in groups W and N were compared using the Student t-test. Stepwise multiple regression analysis, including data from the whole sample, was performed for each tooth region with the thickness of the free gingiva as the dependent variable. The results from the analyses demonstrated that individuals with a long-narrow form of the central incisors displayed, compared to individuals with a short-wide crown, form (l) a narrow zone of keratinized gingiva, (2) a pronounced "scalloped" contour of the gingival margin. There was no significant difference between groups N and W with respect to the thickness of the keratinized gingiva. The CW/CL-ratio data revealed that a certain form of the crowns in the central incisors was accompanied by a similar form in the lateral incisors and canine tooth region. The regression analyses demonstrated that the thickness of the keratinized gingiva in central, lateral incisors and canines was significantly related to the width of the keratinized gingiva.

• Experimental and Molecular Medicine
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• v.50 no.11
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• pp.3.1-3.11
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• 2018

This study aimed to verify the effects of estrogen on the onset and development of adolescent idiopathic scoliosis and the mechanisms associated with these effects by constructing a pubescent bipedal rat model. Experiments were conducted to investigate whether scoliosis progression was prevented by a Triptorelin treatment. One hundred twenty bipedal rats were divided into female, OVX (ovariectomy), OVX + E2, Triptorelin, sham, and male groups. According to a spinal radiographic analysis, the scoliosis rates and curve severity of the female and OVX + E2 groups were higher than those in the OVX, Triptorelin, and male groups. The measurements obtained from the sagittal plane of thoracic vertebrae CT confirmed a relatively slower growth of the anterior elements and a faster growth of the posterior elements between T11 and T13 in the female and OVX + E2 groups than in the OVX and Triptorelin groups. Histomorphometry and immunohistochemistry revealed a significantly longer hypertrophic zone of the vertebral cartilage growth plates that expressed more type X collagen and less type II collagen in the OVX and Triptorelin groups than in the female and OVX + E2 groups. Ki67 immunostaining confirmed an increase in the proliferation of vertebral growth plate chondrocytes in the OVX group compared with the female and OVX + E2 groups. In conclusion, estrogen obviously increased the incidence of scoliosis and curve severity in pubescent bipedal rats. The underlying mechanism may be a loss of coupling of the endochondral ossification between the anterior and posterior columns. Triptorelin decreased the incidence of scoliosis and curve magnitudes in bipedal female rats.

• Journal of Institute of Control, Robotics and Systems
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• v.13 no.9
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• pp.843-850
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• 2007

This paper proposes a somatosensory stimulation system for the improvement of postural stability using vibration as somatosensory stimulation. This system consists of vibratory stimulation and postural response measurement. To evaluate this system, the center of pressure(COP) was closely observed in turn with simultaneous or separate mechanical vibratory stimulations to flexor ankle muscles (tibialis anterior, triceps surae) and two plantar zones on both feet while standing on a stable and an unstable support. The simultaneous vibratory stimulations cleared influenced postural stability and the effects of vibrations were higher with the unstable support. In separate vibratory stimulations, the extent of the COP sway reduced when the direction of the vibratory stimulations and that of the inclination of body coincided for flexor ankle muscle stimulations. In the contrary, the extent of the COP sway increased when the direction of the stimulations and that of body inclination coincided for plantar zone stimulations. These results can be useful for the development of rehabilitation systems that utilizes somatosensory inputs for postural balance.

• Animal Systematics, Evolution and Diversity
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• v.31 no.4
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• pp.277-283
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• 2015

Two pleurostomatid ciliates, Loxophyllum perihoplophorum Buddenbrock, 1920 and L. rostratum Cohn, 1866, were collected from the coastal waters of the East Sea, Korea. Their morphologies are described based on live observation and protargol staining, and morphometrics are provided. Loxophyllum perihoplophorum is characterized by the following features: 200-650 μm long in vivo; body slender leaf-shaped, flexible and contractile, with thin and wide extrusome-belted zone; 2 macronuclear nodules (Ma) and 1 micronucleus (Mi); 7-9 contractile vacuoles (CV) positioned along dorsal margin; extrusomes (Ex) evenly distributed along edge of entire body, with about 10 dorsal warts (Wa); 9-11 left (LSK) and 19-22 right somatic kineties (RSK), 4-5 furrows (Fu) on left side. Loxophyllum rostratum is about 100-130 μm long in vivo; body oblate leaf-shaped, contractile, convex ventral side and S-shaped dorsal side, beak-like anterior end; 2 Ma and 1 Mi; 1 CV terminally located; Ex distributed along edge of entire body, with about 9-10 dorsal Wa; 7-8 LSK and 15-19 RSK, ca. 5 Fu on left body side. In addition, sequences of small subunit ribosomal DNA were determined from these two Loxophyllum species and compared with the known Loxophyllum sequences.

• Animal Systematics, Evolution and Diversity
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• v.24 no.2
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• pp.191-197
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• 2008

Specimens of Diophrys appendiculata (Ehrenberg, ] 838) and D. scutum (Dujardin, 1841) have been collected from the coastal and brackish waters around near Ulsan, during 2004-2007. Diophrys appendiculata and D. scutum are described taxonomically for the first time in Korea. Diagnostic characteristics of these species are as follows. Diophrys appendiculata: size in vivo $43-68{\times}25-50{\mu}m$, adoral zone of membranelles (AZM) covering 43-74% of cell length in impregnated and 46-65% in vivo specimens with 32-47 adoral membranelles (AM). Paroral membrane is slightly curved. Four to five dorsal kinetal (DK) rows are fragmented and anterior and posterior parts of rows densely ciliated. Two macronuclear nodules (Ma) irregular and elongated oval in shape and widely separated. D. scutum: size in vivo $125-225{\times}75-140{\mu}m$, AZM extending to the middle of right border of body and covering 50-60% of cell length with 56-75 AMs. Body shape is typically ovoid with prominent concave margin at right posterio-lateral end, and rather thick and wide longitudinal ridge along lower buccal cavity on ventral side. Two macronuclei shaped like a sausage. five to six dorsal kineties.

• Archives of Reconstructive Microsurgery
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• v.13 no.1
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• pp.29-35
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• 2004

Materials and Methods: Total number of peroneal perforator flap is 14 cases, which 10 cases were man, 4 cases were woman. The range of age was 12 years old minimally and until 63 years old. The trauma was most common etiology, which was like traffic accidents, 9 cases. We confirmed tibialis anterior artery patency by doppler flow meter, angiography as preoperative evaluation. Results: 1. The success rate was 91%, that in 14 cases, 13 cases were succeded. 2. To obtain successful result of peroneal flap, one must have the anatomic concept for vascular pattern, 8 cases were between peroneus muscle and soleus muscle branch type but, 3 cases were through soleus muscle branch type, so we treated these cases by using soleus muscle including peroneal perforating branch not to injury perforating artery directly. 3. The pedicle size was between minimally $2{\times}2.5cm$ and maximally $6.5{\times}8.5cm$ so we could treat large recipient site. 4. The pedicle length was between minimally 3.2 cm and maximally 11.5cm, average 7.5 cm. 5. The diameter of perforating artery was estimated by inspection, that was about 0.2-0.5 cm Conclusion: The peroneal perforating artery flap has merits that we can approach in avascular zone and has wide movable range from foot to distal femur and little donor site mobidity and can harvest osteocutaneous flap. The weak point was the irregular anatomy of nutrient artery and not to contain sensory nerve.