• Restorative Dentistry and Endodontics
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• v.24 no.3
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• pp.482-489
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• 1999

The purpose of this study was to compare sealing ability between lateral condensation and continuous wave of condensation in depend of root canal curvature. In this study, we divided fifty-six human molar teeth into two group in depend of Schneider method, and then subdivided them into four experimental group (each group is composed of twelve teeth) by canal curvature and obturation method, and eight teeth were served as positive and negative controls. Specimens were prepared by Quantac 2000 series file and obturated by lateral condensation or System B. Specimens were immersed in india ink for 7 days, decalcified by 10% nitric acid, dehydrated by 75, 95 and 100% alcohol in order, cleared by methyl salicylate and then measured of dye penetration with stereomicroscope(${\times}6.5$ magnification) and Image Pro plus. The data were analyzed stastically by one-way ANOVA and Scheffe test. The data were as follows: 1. The mean leakage was $0.725{\pm}1.167$ for group A, $0.813{\pm}0.921$ for group B, $0.809{\pm}0.997$ for group C, $1.111{\pm}1.147$ for group D, but no significant difference among them(p>0.05). 2. Lateral condensation had better sealing ability than continuous wave of condensation, but no significant difference among them(p>0.05). 3. There was no significant difference between root canal curvature degree and microleakage(p>0.05).

• Journal of The Korean Society of Integrative Medicine
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• v.10 no.4
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• pp.219-228
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• 2022

Purpose : The purpose of this study was to suggest a more effective method by comparing the effects of changes in pain intensity, muscle strength, and athletic performance after applying a 6-week eccentric training program (ET-MWM) or concentric training program (CT-MWM) with MWM for high school baseball players with shoulder internal impingement (SII). Methods : A total of 75 participants were randomly assigned to each group and divided into two groups, "ET-MWM group (n=35)" and "CT-MWM group (n=32)" according to the intervention method. Pain intensity, muscle strength (external rotation, internal rotation), and athletic performance were first measured before the intervention, and after the intervention 3 times a week for a total of 6 weeks, both groups were re-measured in the same way. Visual analog scale (VAS) was used for pain intensity, biodex dynamometer for muscle strength (60 °/sec.), and Kerlan-Jobe orthopedic clinic shoulder & elbow score (K-KJOC) for athletic performance. Results : As a result of analyzing the homogeneity of the pre-intervention characteristics and initial measurement variables of the study subjects, there was no significant difference between the two groups in all variable values. Pain intensity (VAS) was significantly reduced in the ET-MWM group than in the CT-MWM group (p<.05). In addition, the maximum muscle strength of external rotation & internal rotation of the shoulder (60 °/sec.) and athletic performance (K-KJOC) were significantly increased in the ET-MWM group than in the CT-MWM group (p<.05). Conclusion : Compared with the CT-MWM training program, the ET-MWM training program reduced shoulder joint pain and further increased the muscle strength required for throwing motion in high school baseball players. As the result showed better athletic performance improvement, the ET-MWM training program can be clinically recommended as a more effective intervention.

• The korean journal of orthodontics
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• v.17 no.1
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• pp.55-62
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• 1987

Diagnosis and treatment plans of patients are depended on cephalogram in most case. However, conventional cephalogram may change diagnosis because it ignores a conception of natural head position. The purpose of this study was to investigate the difference of head positions between conventional X-ray taking and x-ray taking in natural head position, and correlation between above results and craniofacial morphology, 60 male students in dental college, Yon sei Univ. were selected, and every cephalogram is studied by comparison of the change of head position. The results are as follows. 1. When taking X-ray by using conventional method, external auditary meatus FH was more tilted than ear rod FM by $2.1^{\circ}{\pm}1.8$ in forward and downward direction. 2. As facial form becomes concave, natural head position and head position, appeared in X-ray taking by using conventional method, become more similiar. 3. Change in head position had showed high correlations with facial form (N-A-Pog angle), and there was high significance to concave group when compared with average group, but significance to convex group was not found. 4. Multiple regression equation concerning change of head position was solved. ${\Delta}FH=24.5\;+\;0.31$ NAPog + 0.43 Prominence of Chin + 0.13 Facial length -0.32 Anterior facial height.

• Journal of Korean Elementary Science Education
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• v.23 no.3
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• pp.208-218
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• 2004

Many elementary school students have misconception related to dissolution and solution. Moreover, they usually fail to apply the results of the experiments in their science classes to their everyday life, and also have low science achievement. Therefore, they are not interested in science, and sometimes some of them are even afraid of it. The purposes of this study is to investigate the effects of concept mapping activity on science achievement and attitude. In addition, this study also aims at presenting the teaching and learning method of utilizing concept maps in order to have the students form correct concepts. The subjects were classified into two groups one group is composed of thirty-seven students (experimental group) who were participated in concept mapping activity, and the other is composed of thirty-eight students (comparison group) who were participated in the traditional teaching method. The major findings of this study are as follows: First, the concept mapping activity has a positive effect on improving students＇ science achievement. Second, the classes using concept maps have a good influence on forming students＇ science attitude. Third, the concept mapping activity is more effective in improving science achievement of mid and low level students. In conclusion, the loaming by concept mapping activity positively influence students＇ science achievement and attitude. Particularly for the students in mid and high levels, the effect is more remarkable.

• The Journal of Advanced Prosthodontics
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• v.9 no.1
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• pp.52-56
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• 2017

PURPOSE. Considering the importance of metal-ceramic bond, the present study aimed to compare the bond strength of ceramics to cobalt-chrome (Co-Cr) alloys made by casting and selective laser melting (SLM). MATERIALS AND METHODS. In this in-vitro experimental study, two sample groups were prepared, with one group comprising of 10 Co-Cr metal frameworks fabricated by SLM method and the other of 10 Co-Cr metal frameworks fabricated by lost wax cast method with the dimensions of $0.5{\times}3{\times}25\;mm$ (following ISO standard 9693). Porcelain with the thickness of 1.1 mm was applied on a $3{\times}8-mm$ central rectangular area of each sample. Afterwards, bond strengths of the samples were assessed with a Universal Testing Machine. Statistical analysis was performed with Kolmogorov-Smirnov test and T-test. RESULTS. Bond strength in the conventionally cast group equaled $74.94{\times}16.06\;MPa$, while in SLM group, it equaled $69.02{\times}5.77\;MPa$. The difference was not statistically significant ($P{\leq}.05$). CONCLUSION. The results indicated that the bond strengths between ceramic and Co-Cr alloys made by casting and SLM methods were not statistically different.

• Nuclear Engineering and Technology
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• v.52 no.2
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• pp.287-295
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• 2020

Group method of data handling (GMDH) is considered one of the earliest deep learning methods. Deep learning gained additional interest in today's applications due to its capability to handle complex and high dimensional problems. In this study, multi-layer GMDH networks are used to perform uncertainty quantification (UQ) and sensitivity analysis (SA) of nuclear reactor simulations. GMDH is utilized as a surrogate/metamodel to replace high fidelity computer models with cheap-to-evaluate surrogate models, which facilitate UQ and SA tasks (e.g. variance decomposition, uncertainty propagation, etc.). GMDH performance is validated through two UQ applications in reactor simulations: (1) low dimensional input space (two-phase flow in a reactor channel), and (2) high dimensional space (8-group homogenized cross-sections). In both applications, GMDH networks show very good performance with small mean absolute and squared errors as well as high accuracy in capturing the target variance. GMDH is utilized afterward to perform UQ tasks such as variance decomposition through Sobol indices, and GMDH-based uncertainty propagation with large number of samples. GMDH performance is also compared to other surrogates including Gaussian processes and polynomial chaos expansions. The comparison shows that GMDH has competitive performance with the other methods for the low dimensional problem, and reliable performance for the high dimensional problem.

• Archives of Plastic Surgery
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• v.37 no.4
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• pp.340-345
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• 2010

Purpose: Recently, bioceramics have become popular as a substitute graft material for reconstruction of bony defect after trauma or tumor surgery. Among the bioceramic materials, hydroxyapatite (HA) is favored due to its biocompatibility. HA scaffold is composed of the interconnected reticular framework, macropores and micropores. Macropores play an important role in cell migration, nutrients supply and vascular ingrowth. On the other hand, a number of micropores less than $10{\mu}m$ form an irregular surface on HA scaffolds, which prevents the osteoblast from adhering and proliferating on the surface of HA scaffold. Methods: In this study, three different groups were designed for comparison. In the first group (group A), conventional method was used, in which HA pellet was applied without surface pretreatment. The second group (group B) was given a HA pellet that has been coated with crystalline HA solution prior to application. In the third group (group C), the same method was used as the second group, where the pretreated HA pellet was heated ($1250^{\circ}C$, 1 hour) before application. Osteoblast-like cells ($2{\times}10^4$/mL) were scattered onto every pellet, then they were incubated in 5% $CO_2$ incubator at $37^{\circ}C$ for twelve days. During the first three days, osteoblast cells were counted using the hemocytometer daily. ALP activity was measured on the 3, 6, 9 and 12 culture days using the spectrophotometer. Results: Under SEM, group A showed a surface with numerous micropores, and group B revealed more rough crystal surface. Group C revealed a fused crystal appearance and flattened smooth surface. In proliferation and ALP activity of osteoblast cells, group C showed better results compared to group B. Group A which lacks pretreatment of the surface showed less osteoblast proliferation and ALP activity than group C, but showed better results than group B. Conclusion: We found that crystallized HA with heat treatment method enhances the osteoblasts proliferation and differentiation on the surface of HA pellets.

• Journal of Haehwa Medicine
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• v.24 no.2
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• pp.1-16
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• 2016

Objectives : This study was designed to evaluate various tools including C-spine X-ray for estimating cervical curvature and identify the effect of wooden pillow on patients diagnosed with straightening of cervical curvature. Methods : This study was carried out on 51 subjects who were encountered traffic accident suffering cervical pain and diagnosed with straightening of cervical curvature by X-ray. 51 subjects were divided into wooden pillow(experimental) group and conservative therapy(control) group. Visual analogue scale, neck disability index and lateral pictures were used and compared after treatment. C-spine AP., Lat. X-ray were used on admission day to calculate cervical curvature and scoliosis by various ways. Results : 4 different measurements of cervical curvature didn't show common results. Both wooden pillow(experimental) group and conservative therapy(control) group showed significant improvement in the visual analogue scale(VAS) and neck disability index(NDI) after hospital treatment. Comparison between center line pictured by lateral view and C-spine Lat. pictured by X-ray showed significant difference in cervical curvature. Lateral deviation of cervical vertebra showed lengthened distance between mastoid process and spinous process of C7. Conclusion : As a result of this research, I found out that various tools for calculating cervical lordosis could derive different results and C-spine AP., Lat X-ray could cause artificial cervical lordosis. According to visual analogue scale(VAS) and neck disability index(NDI) wooden pillow was not effective to reduce pain & disability caused by straightening of cervical curvature. Futhermore, correction effect of straightening of cervical curvature and scoliosis by wooden pillow was weak.

• Journal of Internet Computing and Services
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• v.11 no.5
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• pp.81-94
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• 2010

The purpose of the study is to suggest a standardized teaching-learning model as a method for strengthening the practical effect of the information ethic education for the adolescent, which is practiced in schools as the inter-disciplinary way. A survey was put to teachers and their needs are analyzed. At the same time, in order to draw the practical teaching-learning model, the teaching examples were collected for contesting. Through this process, a bottom-up approach which tries to analyze the actual class examples and generalizes them, the teaching-learning model has been suggested. As a result, another survey was conducted for the investigation of the efficacy of the model between beneficiary group and comparison group. The results are as followings; the experiment group showed a higher index in regard with such items as Information Culture Index, Lesson Satisfaction Degree, and Practice Will than Comparison Group, and the differences are statistically significant. According to the results of the analysis.

• Journal of Korean Physical Therapy Science
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• v.9 no.1
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• pp.53-59
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• 2002

This study is research for effect of the involved lower limb weight bearing training on symmetrical weight supporting rate improvement by practicing involved lower limb weight bearing training of three weeks period to improve standing equilibrium problem with asymmetric weight supporting rate of hemiplegia. In result of the study, it has shown that P-value incase of involved supporting rate is lower than level of significance $\alpha$<.05 and mean improvement rate of experienced group is higher in comparison with controlled group and experienced group. In changing quantity of involved maximum supporting rate, P-value is .26 and higher than level of significance $\alpha$<.05, and so it did not show significant difference statistically. But in case of experienced group between pre and post-test, involved side supporting rate and involved side maximum supporting rate showed significant improvement in all. In comparison of relative characteristic training effect difference, it was shown that train-learning effect on case of 40-60 years old, hemorrhagic patient and standard body bun of patient is valuable, which showed significant improvement in case of paralytic side and disease period, it did not show significant difference on excercise learning effect in two above cases. In the above result, we can say that continuous weight bearing training on the involved lower limb for three weeks period help improve the involved side supporting rate of hemiplegia. Accordingly, the weight bearing training on the involved lower limb is training method that patient can easily train with simple guidance of therapists, without being special expensive equipment. Furthermore it can be helpful to establish home therapeutic plan for hemiplegia through education of a patron.