• The korean journal of orthodontics
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• v.40 no.3
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• pp.184-194
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• 2010

Objective: The purpose of this study was to investigate the effect of tribochemical silica coating on the shear bond strength (SBS) of rebonded ceramic brackets using nano-filled flowable composite resin. Methods: A total of 60 premolars were prepared and divided into 4 equal groups as follows: Tribochemical silica coating (TC) + Transbond XT (XT), TC + Transbond supreme LV (LV), Sandblast treatment (SA) + XT, SA + LV. Treated ceramic brackets were rebonded on the premolars using each adhesive. All samples were tested in shear mode on a universal testing machine. Results: SBS of silica coated groups were high enough for clinical usage (TCLV: 10.82 $\pm$ 1.82 MPa, TCXT: 11.50 $\pm$ 1.72 MPa). But, SBS of the sandblast treated groups had significantly lower values than the tribochemical silica coated groups (SALV, 1.23 $\pm$ 1.16 MPa; SAXT, 1.76 $\pm$ 1.39 MPa; p < 0.05). There was no difference between the shear bond strength by type of adhesive. In the silica coated groups, 77% of the samples showed bonding failure in the adhesive. In the sandblast treated group, all bonding failures occurred at the bracket-adhesive interface. Conclusions: The result of this study suggest that newly introduced nano-filled flowable composite resin and tribochemical silica coating application on debonded ceramic bracket bases can produce appropriate bond strengths for orthodontic bonding.

• Korean Journal of Ichthyology
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• v.6 no.1
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• pp.51-59
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• 1994

Morphology of glochidia of two species of Unionidae mussels, Unio douglasiae and Anodonta woodiana were studied based on SEM, and their attachment on Acheilognathus yamatsutae(Acheilognathinae) was observed in the experimentally infected fishes. The glochidia were round-triangle in shape and possessed larval threads, hooks, hooklets, and sensory hairs. Glochidal attachment and cyst formation of the fish were observed without regard to feeding habit and habitat. Density of glochida on the fish (Acheilognathus yamatsutae) was in the order of pectoral fin, dorsal fin, gill and caudal fin. The host fish became encysted about 5-10 hours to the glochidia, and the glochidia detached about 5-6 days after attachment at water temperature $26{\pm}1^{\circ}C$.

• Applied Microscopy
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• v.39 no.2
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• pp.117-124
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• 2009

Clonorchis sinensis is the most important widely distributed parasite of the human bile duct in East Asia and the most prevalent parasitic helminth in Korea. The prevalence rate of human clonorchiasis has remained at about 2.9% in Korea. C. sinensis induces dilatation of the duct, hyperplasia of the mucosa, metaplasia or neoplasia of the mucosal epithelium, periductal inflammation and fibrosis, and thickening of the ductal wall. Fibroblast are the most common cells in connective tissue and are responsible for the synthesis of extracellular matrix components. The fibrosis associated with chronic inflammation and injury may also contribute to cholangiocarcinoma pathogenesis, particularly through an increase in extracellular matrix components, which participate in the regulation of bile duct differentiation during development. In this study, ultrastructural changes, the distribution of lectin receptors and actin protein in cultured SD rat bile duct fibroblast after infection of C. sinensis were observed. Experimental group had been divided into four groups: normal bile duct fibroblast cultured in basal media (G1); C. sinensis infected bile duct fibroblast cultured in basal media (G2); normal bile duct fibroblast cultured in basal media containing excretory-secretory product (ESP) (G1-1); C. sinensis infected bile duct fibroblast cultured in basal media containing ESP (G2-1). Overall, once a host is infected by C. sinensis, it affects the host to the extent that sialic acid of ductal fibroblast is increased. Number of cytoplasmic process of SD rat bile duct fibroblast was increased. Actin protein and sialic acid were located in cell surface. Fibroblast induced by C. sinensis was not recovered to normal fibroblast. The cytoplasm bulk and cytoplasmic process were increased whereas the growth rate of the fibroblast of infected SD rat was reduced rather than that of normal fibroblast. In result, it inhibits fibroblast proliferation and increases actin protein on fibroblast cytoplasm, and so causes fibroblast metamorphosis and cellular mutation.

• Journal of the korean academy of Pediatric Dentistry
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• v.27 no.1
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• pp.161-168
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• 2000

The purpose of this study was to develop a practical caries activity test using laser fluorescence. The subjects of study were 30 children of $7\sim10$ years old. Fluorescence from initial carious lesion of teeth illuminated by an argon laser(488nm) was observed through barrier alter. For evaluation of accuracy and propriety of this method fer caries activity test, teeth with initial caries lesion on buccal or labial surface of children was examined with visual inspection and laser fluorescence. Visual examination for the dDfFtT and the $Cariescreen^{(R)}$ test were also done. The results from the present study can be summarized as follows: 1. Laser fluorescence test could differentiate initial caries lesions more easily than visiual inspection. 3. There was highest correlation(= 0.73) between laser fluorescent test and $Cariescreen^{(R)}$ test and. And also apparent correlation(= 0.66) exists between laser fluorescent test and caries experience measured by dDfFtT.

• Applied Microscopy
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• v.36 no.1
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• pp.17-23
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• 2006

The pregnant rats were given a drinking water administration of the sodium fluoride and normal saline for control animals. The sodium fluoride produced cellular changes of odontoblast with consistent response. Compare to control group, the odontoblasts that were administrated by sodium fluoride, showed significantly ultrastructural differences including large number of free ribosomes and swelled mitochondria in dose-dependent manner (300 ppm). From fine structural and morphological investigations of the changes in odontoblast, there were three distinctive structural changes: (1) destruction of the endoplasmic reticulum, (2) swelling of the mitochondria, and (3) severe cellular derangement of the endoplasmic reticulum and mitochondria. From this consecutive structural change, we observed that sodium fluoride temporarily affects the cell organelles in odontoblasts (100, 200 ppm), suggesting it is important that optimal concentration of the sodium fluoride in developing fetus of the rat.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2006.05a
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• pp.495-500
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• 2006

본 논문에서는 셀 환경에서 QoS를 보장하기 위해 통합된 페이징과 루프 정보 관리 캐시를 사용하는 Cellular IP 특성을 가진 Cellular-IP/PRC 네트워크를 제안한다. 제안한 호 수락 방식은, 이동 노드의 홈 기지국 용량이 충분하고, 인접 셀 이동 노드가 흠 기지국에서 호가 수락되었다고 가정할 경우 받을 간섭의 증가량을 고려해 통화 품질이 보장될 때, 홈 기지국은 새로운 호를 이동 노드의 송신 전력 예측에 기반을 둔 호 수락 방식이다. 무선인터넷 네트워크 내의 페이징과 라우터를 관리하기 위해 사용되었던 PC(Paging Cache)와 RC(Routing Cache)를 하나의 PRC(Paging Router Cache)로 통합 관리하고, 모든 노드 내에 구성하여 운용토록 하고, 이동 노드의 핸드 오프 및 로밍 상태를 효율적으로 관리 할 수 있도록 이동 노드에 핸드오프 상태 머신을 추가하고, 노드에서 관련 기능을 수행하도록 하였다. 시스템 환경에서 통화량에 영향을 주는 인자를 각 링크 통화권 및 불균형 정도를 예측, 하향링크에 의해 통화권이 제한을 판단하여 송수신 전력을 기반으로 한 알고리즘과 제안한 알고리즘을 비교하여 QoS가 호 차단 확률과 호 탈락 확률, GoS, 셀 용량의 효율을 예측할 수 있는 QoS로 성능 개선을 연구한다.

• Journal of the Korean Recycled Construction Resources Institute
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• v.5 no.3
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• pp.267-274
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• 2017

This study discusses the applicability of environmental friendly EVA based butyl rubber self-adhesive waterproof sheet designed to prevent corrosion of large scale pipes used in the water treatment facilities during th water treatment process. The experiments conducted tested the waterproofing sheet's adhesion strength on the steel surface of the pipes and checked for whether the material has the proper response properties against the various environmental conditions. In addition, it the sheet adhered to the steel pipe was to see if the adhesion hold against the water pressure due to the ingress of inflow water. Finally, the waterproofing sheet's adhesion strength was tested on a rusted steel surface to confirm whether the material has the necessary properties to secure stable adhesion strength and prevent corrosion of steel pipes at the same time during the process of installation or maintenance. As a result, the self-adhesive waterproof sheets showed that all attachments in the untreated, long term pressuring, immersion in chemical substance (hydrochloric acid, hypochlorous acid, sodium hydroxide), low temperature ($-20^{\circ}C$) conditions showed a adhesion performance of higher than 1.5N/mm, which is the performance standard of KS F 4934. Also, in the testing to check for the adhesion property against inverse water pressure, it was observed that the adhesion failure did not occur even up to $3.0N/mm^2$ pressure. Also, in the process of assessing the adhesion performance on rusted steel surface, specimens after 12 hours of corrosion treatment was shown to have 2.1N/mm, and specimens after 168 hours of corrosion treatment was shown to have 2.0N/mm adhesion strength performance.

• The Journal of Korean Association of Computer Education
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• v.14 no.1
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• pp.169-174
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• 2011

Recently, Korean government has, enacted "Individuals with Disabilities anti-Discriminatory Act" in 2008, and is actively promoting the law. However, it is still at its infancy in comparison to other advanced countries in terms providing access for all users. Educational digital contents offered through cyber home learning need to be universally designed to include all learners. This study, I have analyzed the accessibility of K cyber home learning contents using FAE tool, and the result showed low scores or failed for 'HTML Standards', 'Scripting' and the 'Text Equivalents.' To assist digital contents' accessibility, UDL 7 principles could be use to improve accessibility and universality for learner-centered designs. Use of UDL will include learners with and without disabilities to learn from educational digital contents.

• Korean Journal of Human Ecology
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• v.21 no.3
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• pp.587-596
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• 2012

Alopecia is usually presented as patchy, no scarring hair loss. It seems to be a hormonal imbalance or an immune mediated disease, whereas genetic predisposition, environmental and psychological factors may be involved in its etiology. Many treatments of alopecia disease have been widely applied, but their side effects are also well known. The purpose of this study is to demonstrate efficacy and safety of a food supplement containing medicinal plant extracts, amino acid and vitamin complex on the prevention of hair loss in human. A total of 20 subjects aged between 29-50 years with subjective hair loss complaint were recruited for this study. Each subject took 1 g/day supplement for 3 months. 5-Scale self-assessment test, hair loss count and measurement of hair thickness were conducted to evaluate the effect of supplement on the improvement of hair loss. Subjective hair loss was decreased and hair damage and thickness were improved in self-assessment test. After 3 months of supplementation, hair loss counts were decreased (P<0.05) while hair thickness was increased(P<0.001) significantly. There was no side effect observed during the study. These results suggest that the supplement consist of medicinal plant extracts, amino acid and vitamin complex might be useful for the improvement of hair loss with no significant side effects.

• Journal of Preventive Medicine and Public Health
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• v.15 no.1
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• pp.153-159
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• 1982

A statistical study on medical students who entered certain college of medicine during 10 years ('73 to '82) was performed in order to evaluate medical educational wastage. The obtained results summerized were as follows; 1. The normal promotion rate of 10 cohorts(CI-CX) was 83.4% and 5 cohorts(CI to CV) whose members had already graduated(including dropouts) was 77.5%. 2. The mean repetition rate in 1st grade was 15.5%, in 2nd grade 5.4%, in 3rd grade 1.4% arid in 4th grade 0.6%. 3. The predicted number of repetion(spell base) which are attendance at the college in 1st grade was 31.6, in 2nd grade 28.9, in 3rd grade 18.6 and in 4th grade 22.7; 4. The total wastage of 10 cohorts was 224.8 SY, which corresponded to educational resources of 56.2 out-puts for normal demand. 5. The mean unit cost of 10 cohorts was 4.62 and the mean Input/Output ratio was 1.06.