• The Bulletin of The Korean Astronomical Society
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• v.45 no.1
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• pp.51.1-51.1
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• 2020

The Rosette Nebula is the most actively star-forming region in the Monoceros OB2 association. This region hosts more than three stellar groups, including the most populous group NGC 2244 at the center of the region and the smaller stellar groups around the border of the H II bubble. To trace their formation process, we investigate the kinematic properties of these groups using the Gaia astrometric data and high-resolution spectra taken from observation with Hectochelle on MMT. The proper motions of stars in NGC 2244 show a pattern of radial expansion. The signature of cluster rotation is also detected from their radial velocities. On the other hand, the small groups appear to be physically associated with some clouds at the ridge of the H II region. Among them, the group near the eastern pillar-like gas structure shows the signature of feedback-driven star formation. In this presentation, we will further discuss the formation process and dynamical evolution of the stellar groups in the Rosette Nebula, based on the observation and results of N-body simulations.

• The Journal of Korean Association of Computer Education
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• v.8 no.4
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• pp.15-24
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• 2005

The success of cooperative learning in small groups heavily depends on how the small groups are set up. When small groups are formed, the factors such as the objectives and characteristics of the work and the capabilities and interests of the group members should be considered to maximize the interaction among the group members. However, it is not easy for teachers to manually divide their class to small groups to satisfy such conditions. In this work, we developed and implemented a student grouping system that divides the class as appropriate as possible, when given multidimensional student data and a set of conditions for forming small groups. The grouping conditions can be heterogeneous, homogeneous, and both. The grouping system can easily be used by teachers since the system can be accessed by clicking a menu button embedded into Microsoft Excel. The system has also a wide range of application areas where object grouping by various conditions is needed.

• Journal of Periodontal and Implant Science
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• v.32 no.4
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• pp.801-809
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• 2002

The ultimate goal of periodontal therapy is to promote the regeneration of lost periodontal tissue, there have been many attempts to develop a method to achieve this goal, hut none of them was completely successful. The purpose of this study is to evaluate the effects of Bio-Oss(R) on alkaline Phosphatase (ALP) activity in human fetal osteoblasts (hFOB1). The results of this study were as follows, in ALP Activity, 100 ${\mu}g/ml$ Bio-Oss(R) treated group showed significantly increased value than negative control group, but positive group($10^{-7}$ M dexamethasone treated group) showed the highest ALP activity at 3 day. In mineralization assay, numerous mineralized nodules were identified as darkly stained spots in 100${\mu}g/ml$ Bio-Oss(R) treated group than two control groups, whereas a small number of mineralized nodules were showed in the positive control. ALP may relate to the initial phase of bone nodule formation. On the basis of these results, this study showed Bio-Oss(R) is capable of accelerating new bone formation through hFOBl differentiation in vitro.

• Journal of Veterinary Clinics
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• v.11 no.1
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• pp.427-436
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• 1994

To investigate the effect of yeast glucan on wound healing in rabbits, histopathological findings and wound contraction after topical application of glucan on the open wound were observed. Formalin fixation and embedding of tissues at wound were prepared for histopathological findings at the other day after wounding. Wound size was measured for contraction. Macrophages appeared in the deeper site under the scab at day 1 after wounding in the glucan treated group, but not in the control. A number of macrophages, fibroblasts and a small number of neutrophils were observed at day 3 after wounding In the glucan treated group as compared with the control. Histopathological findings at day 5 after wounding in control were similar with those at day 3 in the glucan treated group. Glucan like granules were scattered in the cytoplasm of macrophages at day 5 in the glucan treated group. A great portion of wound reepithelialized at day 5 in the glucan treated group but a small portion of wound in the control. The Present study indicated that the treatment of 5,000$\mu\textrm{g}$/$m\ell$ of glucan has an effect on wound heal. ins in respect to migration of macrophage into the wound site, granulation tissue formation and epithelialization.

• Journal of Periodontal and Implant Science
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• v.52 no.4
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• pp.325-337
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• 2022

Purpose: The aim of this study was to investigate the effect of (1) the size of the bony access window and (2) collagen membrane coverage over the window in sinus floor elevation in a rabbit sinus model. Methods: Small bony access windows (SW; ø 2.8 mm) were made in 6 rabbits and large windows (LW; ø 6 mm) in 6 other rabbits. Both sinuses in each rabbit were allocated to groups with or without coverage of a collagen membrane (CM) on the window, resulting in 4 groups: SW, LW, SW+CM, and LW+CM. After 4 weeks of healing, micro-computed tomographic, histologic, and histomorphometric analyses were performed. Results: Bony healing in the window area was incomplete in all groups, but most bone graft particles were well confined in the augmented cavity. Histologically, the pattern of new bone formation was similar in all groups. Histomorphometrically, the percentage of newly formed bone was greater in the groups with CM than in the groups without CM, and in the groups with SW than in the groups with LW (12.92%±6.40% in the SW+CM group, 4.21%±7.73% in the SW group, 10.45%±4.81% in the LW+CM group, 11.77%±3.83% in the LW group). The above differences were not statistically significant (P>0.05). Conclusions: The combination of a small bony access window and the use of a collagen membrane over the window favored new bone formation compared to other groups, but this result should be further investigated due to the limitations of the present animal model.

• Korean Journal of Bronchoesophagology
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• v.4 no.2
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• pp.177-181
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• 1998

Provox is now widely used for voice rehabilitation for total laryngectomized patient because of its low airway resistance and easiness for phonation. This study was designed to reveal the influence of radiation therapy on Proven complications. Forty-four patients who underwent total laryngectomy were grouped into group A (no radiation), group B(radiation and then Provox insertion), group C(Proven insertion and then radiation). Provox complications were leakage, granulation tissue formation, malfunction and infection. The average survival time of Provox was longer in group C (9.2 me) than group A(8.6 m) or group B (7.3 me), but no statistical significance was found. The first time of Provox change was 10.2, 8.6 and 9.7 months respectively. The incidence of complication was not significantly different among groups. The cases of Provox remeval due to shunt failure were 5, 4 and 2 respectively. Even though a significant statistically difference was not found partialy due to the small numbers of patients, a special caution should be exercised in inserting Provox to prevent a serious complication for the patients who had a history of previous radiation.

• Maxillofacial Plastic and Reconstructive Surgery
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• v.21 no.1
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• pp.13-22
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• 1999

The purpose of this investigation was to evaluate the acceptability of the collagen-based xenograft ($Laddec^{(R)}$). Full thickness bone defects were prepared in the calvaria of the rats. In the experimental groups the bone defects were filled with a kind of collagen based xenograft. And bone defects, which left without filling, were used as control groups. Sequential sacrifice was performed at the 1st, 2nd, 4th, 8th, and 16th weeks of experiment. 1. At the 1st week of experiment, infiltration of chronic inflammatory cell was observed in all groups. In the experimental group, resorption of the xenograft was initiated. 2. At the 2nd week of experiment, infiltration of chronic inflammatory cells was decreased in all groups. In the experimental group, active resorption of xenograft and new bone formation from the periphery of the xenograft was observed. 3. At the 4th and 8th weeks of experiment, more resorption of the xenograft and new bone formation with calcification was observed in the experimental group. 4. At the 16th week of experiment, small bone trabecula was formed partially in the control group but that couldn't fill the whole bone defect. In the experimental group, more advanced resorption of xenograft and more new bone formation was observed. However mid portion of the xenograft was still remained without resorption. 5. From this experiment, we concluded that the collagen-based xenograft had some osteoconductive but no osteoinductive property. So the xenograft would be used for the bone defect filling material where rapid bone remodeling is not required.

• Journal of Animal Reproduction and Biotechnology
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• v.38 no.2
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• pp.70-76
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• 2023

Background: Despite considerable technological advancements, polyspermy remains a significant challenge in in vitro fertilization (IVF) procedures in pigs, disrupting normal embryonic development. Here, we aimed to determine whether optimal fertilization conditions reduce the polyspermy incidence in pigs. Methods: In vitro-matured oocytes were co-incubated with sperm according to a modified two-step culture system. Results: In the first experiment, oocytes were briefly co-incubated with sperm, washed in IVF medium, and then moved to fresh IVF medium for 5 or 6 h. Although the 6 h sperm-free cultured group had a higher penetration rate than the 5 h cultured group, the polyspermy rate significantly increased in the 6 h sperm-free cultured group. The gamete co-incubation period was either 20 or 40 min. The 40 min cultured group had a higher rate of blastocyst formation and number of total cells in blastocysts than the 20 min cultured group. In experiment 2, oocytes were inseminated with sperm separated by Pecroll treatment. Percoll treatment increased the rate of oocyte penetration and blastocyst formation compared to the control. In experiment 3, fertilized oocytes were cultured in 25 µL microdroplets (10 gametes/drop) or 500 µL (100 gametes/well) of culture medium in 4-well plates. The large volume of medium significantly reduced the number of dead oocytes and increased the rate of blastocyst formation compared to the small volume. Conclusions: Collectively, these results demonstrate that various fertilization conditions, including modified co-culture period, active sperm separation, and culture medium volume, enhance fertilization efficiency and subsequent embryonic development by decreasing polyspermy occurrence.

• Journal of the korean academy of Pediatric Dentistry
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• v.24 no.3
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• pp.660-677
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• 1997

The purpose of this study was to examine the morphological characteristics and combined effects of fluoride application and laser irradiation on artificial caries-like lesion formation in bovine enamel. Enamel specimens were divided into five experiment group and placed in no-treatment(group C), APF application alone(group F), laser irradiation alone(group L), APF application before laser irradiation (group FL), and APF application after laser irradiation(group LF) on artificial caries-like lesion. Sound enamel was used as a control group. The ultrastructural changes and physical effects of the fluorided and lased enamel has been investigated by using SEM, enamel solubility and microhardness test as well as distributions of calcium, phosphorus and fluoride in internal enamel by using EPMA. The following results were obtained. 1. In the all experiment groups, the amounts of dissolved calcium of enamel surfaces significantly decreased according to increasing exposure time of acid solution than control group(P<0.001). Group L showed higher than that group FL and LF in 30 and 60min(P<0.05). 2. The microhardness values of enamel surface in the control group was highest than that in the other experiment groups. Group F, L, FL and LF were significantly increased than group C(P<0.001). The enamel surface treated with APF produced deposites of numerous small globules and lased enamel showed a cracker-like appearance with microcrack and small pore. Numerous deposits were infiltrated in the fissured portion of enamel treated with APF after laser irradiation. 4. In the case of APF application alone, the elevation of the fluoride profile can be seen within $5{\mu}m$ of the outermost layer and a similar profile observed in the specimen treated with APF before laser irradiation. However, the specimen treated with APF after laser Irradiation showed a large elevation within $10{\mu}m$ of the outermost layer of the enamel. 5. The higher Ca/P ratios were observed in $10{\mu}m$ depth of lased and fluorided enamel when compared to the sound and carious enamel. The fluoride content decreased rapidly with distance from enamel surface, in the group F, fluoride concentration was significantly higher than that in the group C, L, FL, LF and control group according to increasing enamel depth (P<0.05).

• Journal of The Korea Institute of Healthcare Architecture
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• v.13 no.3
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• pp.57-65
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• 2007

Over the last years several studies have been carried out in the welfare facilities for the elderly in Japan. These have mainly focused on small scale projects, multi-functional houses and on the improvement of specifically designed equipments. This study examines the residents' life patterns and using patterns in group living having various space constitution and, does it for the purpose of looking for the formation of well state places, life patterns and the domains to use spaces for the aged who became independent. I intend to grasp their life patterns by physical space constitution and to show a direction of the house form that they can live in while feeling relieved in areas.