• The korean journal of orthodontics
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• v.27 no.3 s.62
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• pp.391-399
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• 1997

Rapid palatal expansion(RPE) is a method of inducing the new bone formation in the palate by separation of the midpalatal suture, which can be done conveniently by placing heavy force across the maxillary dental arch. This experiment was undertaken to examine the histologic changes after RPE and during retention period. Four young adult dogs(a control dog, three experimental dogs) aged 4 to 6 months old were used for this experiment. Expansion screw($Hyrax^{\circledR}$, Dentarum Inc.) was delevered to the palate and fumed 180 degrees every morning and evening for 8 days, giving a total expansion of 7.2mm. A control dog was sacrified at the starting point of this study without any treatment and three experimental dogs were sacrified after RPE, 14-day retention, and 28-day retention in each. Thereafter, those samples were observed with hematoxylin-eosin(H-E) stain, ground section(Villanueva stain), alkaline phosphatase(ALP) stain, tartrate-resistant acid phosphatase(TRA) stain. The results were as followings: 1. After RPE, collagen fiber bundles were stretched along the midpalatal suture and few osteoblasts were flattened-inactive state and also, a little osteoid tissues was observed. Few multinucleated osteoclasts which had TRAP-positive activity in their cytoplasm were seen in horizontal section, whereas a few osteoclasts were seen in frontal section, especially in the nasal floor side of palatal bone. 2. After 14-day retention, collagen fiber bundles were stretched along the midpalatal suture and few osteoblasts which had ALP-positive activity in their cytoplasm were seen. Few multinucleated osteoclasts which had TRAP-positive activity in their cytoplasm were seen in horizontal section, whereas a few osteoclasts were seen in frontal section, especially in the nasal floor side of palatal bone. 3. After 28-day retention, collagen fiber bundles were arranged like those of control dog and osteoblasts which showed a lot of immature bone formation were cuboidal shape and exhibited ALP-positive activity in their cytoplasm. Few multinucleated osteoclasts which had TRAP-positive activity in their cytoplasm were seen in horizontal section, whereas a few osteoclasts were seen in frontal section, especially in the nasal floor side of palatal bone. According to the above results, the new bone formation after rapid palatal expansion was examined after 14-day retention and significantly increased after 28-day retention.

• Parasites, Hosts and Diseases
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• v.31 no.2
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• pp.135-140
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• 1993

An experimental study was performed to observe the infectivlty of sparganum (plerocercold of Spirometra erinncel) treated by prazlquantel, gamma-irradiation and mechanical cutting. The spargana were obtained from the naturally Infected European grass snake, Rhabdophis tigrina, or from the expenmentally infected mice. A total of 83 mice (ICR straine were divided Into 3 experimental groups by the source of the damage, fed each UH 5 spargana, and sacnaced 1 month later for worm recovery. In the praziquantel group, the worms were incubated In the concentration of 10㎍/ml (control: Tyrode for 4 hours) for 0.5. 1.2 and 4 hours at 36℃. and fed to mice. The recovery rate from mice in prazlquantel group was not different from that (80%) of control poop and in the range of 76-100%. In the gamma-Irradiation group, the worms were irradiated by 10-1000 Gy with Csl37. The average recovery rates of 69-100% were not different from that of control up to 100 Gy. The rate was 56% under 150 Gy, and 5% by 1000 Gy. In the mechanical cutting group, the worms were cut at 0.5, 1, 2 and 3 m from the anterior end of the scolex. The average recovery rates In each group were 70-90% and that of control was 90%. The present folding suggests that the sparganum be highly resistant to prazlquantel, gamma- irradiation and mechanical cutting. The vitality center of the sparganum must be at the anterior end of Its scolex.

• Microbiology and Biotechnology Letters
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• v.17 no.3
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• pp.183-187
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• 1989

The bacteriophage Mu and transposon Tn5 containing plasmid pJB4JI-transferred transposon Tn5 to Caulobuter crescentus. When several thousand of transposon Tn5 insertion mutants were examined, we found auxotrophic and motility mutants at frequencies of 2％ and 3％, respectively. Transposition of transposon Tn5 was analyzed by the reverse field electrophoresis and Southern hybridization. The results indicated that transposon Tn5 was randomly inserted to Caulobuter crescentus chromosome but the plasmid vector, pJB4JI, was not maintained.

• Korean Journal of Plant Tissue Culture
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• v.25 no.3
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• pp.201-206
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• 1998

To develop the fruits of cucumber (Cucumis sativus L.) producing high yields of superoxide dismutase (SOD), the MnSOD cDNA from pea (Pisum sativum) under the control of the cauliflower mosaic virus 35S promoter was introduced into cucumber using Agrobacterium tumefaciens (strain LBA 4404)-mediated transformation. The kanamycin-resistant shoots were selected on the selection medium containing MS basal salt, 1.0 mg/L zeatin, 0.1 mg/L IAA, 300 mg/L claforan, and 100 mg/L kanamycin. After 6 weeks of culture on the selection medium, the shoots were transferred to MS medium containing 0.2 mg/L NAA to induce roots. PCR analysis using the primers for neomycin phosphotransferase (NPTII) gene revealed that three plantlets were transformed. The fruits of one transgenic plant had approximately 3.2-fold higher SOD activity than those of non-transgenic plants. MnSOD isoenzyme band was strongly detected on native gel in fruits of transgenic plants.

• The korean journal of orthodontics
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• v.31 no.5 s.88
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• pp.517-523
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• 2001

Titanium miniscrews we being used increasingly as an anchorage for tooth movement, because they ate easy to place and to remove, increase the number of sites available, give minimum strain to patients regarding surgical procedures, and offer uneventful healing alter removal. The use of titanium miniscrews as an orthodontic anchorage has been reported in clinical case reports, but clinicians have experienced screw loosening when using such screws.' To our knowledge, there are no published reports evaluating the stability of miniscrews. Information about the length of miniscrews used in relation to the location is of some importance, as stability will vary depending on bone duality The purpose of this study was to evaluate a variety of Lengths of miniscrews (dimeter: 2mm) which were inserted in maxilla or mandible and to demonstrate in a dog model which miniscrew provides fundamental stability in the jaws. 10 mm long miniscrews in the maxilla and 8mm long: miniscrews in the mandible showed no clinical mobility and retained their position throughout an 8 weeks force (200g) application. The mucosal condition around the screws was healthy in cases in which miniserews were inserted in the alveolar bone between the roots and the head of the screws emerged into the attached gingiva. When the force application was terminated, radiographic analysis revealed neither rent resorption not periodontal pathology around the miniscrews that remained stable during the entire treatment period. This study suggests that if titanium miniscrews with adequate length are properly used depending on the location, they provide sufficient stability for orthodontic anchorage.

• Restorative Dentistry and Endodontics
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• v.34 no.5
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• pp.424-429
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• 2009

This study aimed to assess the influence of different cross-sectional area on the cyclic fatigue fracture of Ni-Ti rotary files using a fatigue tester incorporating cyclical axial movement. Six brands of Ni-Ti rotary files (ISO 30 size with. 04 taper) of 10 each were tested: Alpha system (KOMET), HeroShaper (MicroMega), K3 (SybronEndo), Mtwo (VDW), NRT (Mani), and ProFile (Dentsply). A fatigue-tester (Denbotix) was designed to allow cyclic tension and compressive stress on the tip of the instrument. Each file was mounted on a torque controlled motor (Aseptico) using a 1:20 reduction contra-angle and was rotated at 300 rpm with a continuous, 6 mm axial oscillating motion inside an artificial steel canal. The canal had a $60^{\circ}$ angle and a 5 mm radius of curvature. Instrument fracture was visually detected and the time until fracture was recorded by a digital stop watch. The data were analyzed statistically. Fractographic analysis of all fractured surfaces was performed to determine the fracture modes using a scanning electron microscope. Cross-sectional area at 3 mm from the tip of 3 unused Ni-Ti instruments for each group was calculated using Image-Pro Plus (Imagej 1.34n, NIH). Results showed that NRT and ProFile had significantly longer time to fracture compared to the other groups (p < .05). The cross-sectional area was not significantly associated with fatigue resistance. Fractographycally, all fractured surfaces demonstrated a combination of ductile and brittle fracture. In conclusion, there was no significant relationship between fatigue resistance and the cross-sectional area of Ni-Ti instruments under experimental conditions.

• Korean Journal of Agricultural Science
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• v.13 no.1
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• pp.103-112
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• 1986

This study was carried out to prevent the entwining of rice straw on rotary shaft and blade where rice straw was spreaded on paddy field as an organic source before rotary tilling. The rotary tillage was conducted in the paddy field having the soil moisture contents of 30%, 39%, 59% in dry basis and spreaded rice straw (450kg/10a) of 30cm, 45cm, 90cm length with the edged curve angles of rotary blade of $30^{\circ}$, $40^{\circ}$, $50^{\circ}$, $55^{\circ}$ at Yuseung area. And the test were performed on the plot which has width of 30cm and 5cm length and the quantity of entwined rice straw was analized. The test results were summarized as the followings. 1. Entwining phenomenon of rice straw was decreased as the blade edged curve angle increased. The edged curve angle of rotary blade must be determind by considering the characteristics of soil cutting resistance, tilling torque and entwining phenomenon of rice straw. But according to the entwining phenomenon of rice straw only, the edged curve angle of rotary blade should be bigger than $55^{\circ}$ for design. 2. Amount of entwining rice straw was minimized when soil moisture contents was 30 percent (d. b.). It would be better that rotary tillage is performed when soil moisture contents is lower than 30 percent in dry basis. 3. Amount of entwining rice straw was minimized when the length of rice straw was 30cm with $55^{\circ}$ edged curve angle. Therefore, it would be better to chop rice straw as 30cm. 4. Entwining phenomenon of rice straw was decreased as the forward speed decreased. To decrease the entwining rice straw, rotary tillage should be done with forward fist gear (0.35m/s).

• The korean journal of orthodontics
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• v.20 no.1
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• pp.47-59
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• 1990

Respiration is one of the most important functions which are carried out in stomatognathic system. When nasal orifice is obstructed or the resistance of upper airway is increased mouth breathing is initiated. Mouth breathing is regarded as an important etiologic factor of dentofacial anomalies. This experiment was performed to observe the influences of metabolic acidosis, tracheal resistance and vagotomy on mouth breathing. After rabbits were anesthetized with sodium pentobarbital, a pair of wire electrode was inserted into mylohyoid muscle, anterior belly of digastric muscle and dilator naris muscle to record EMG activity. Femoral vein and artery were cannulated for infusion of 0.3N HCl and collection of blood sample to determine the blood pH, and tracheal intubation was done to control airway resistance. Mouth breathing was induced by metabolic acidosis. Increase of the airway resistance through tracheal cannula intensified the activity of dilator naris, mylohyoid and digastric muscle. The higher the resistance, the larger the EMG amplitude. After bilateral vagotomy, respiratory volume and inspiatory time were increased and the activities of dilator naris, mylohyoid and digastric muscle were strengthened. It was concluded that the muscle activity related to mouth breathing was induced by metabolic acidosis and increase of tracheal tube resistance.

• Korean Journal of Cleft Lip And Palate
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• v.5 no.2
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• pp.113-116
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• 2002

편측 왜소증의 얼굴을 상하악과 하악 모두 신장할 필요가 있는 경우 하악을 신장하여 상악도 신장시키는 방법을 최근 소개한 바 있으나 본 논문에서는 오히려 상악을 신장시킬 때 하악도 같이 신장시키는 방법을 개발하여 좋은 결과를 얻었다. 두 명의 편측안면 왜소증 환자에서 양악 동시에 골 신장술을 시행하였다. Ortiz Monasterio의 방법과 달리 상악은 구내 르포트씨 제일 골절단술을 시행하였고, 하악은 구내 시상분할 골 절단술을 이용하여 골신장시 저항을 최소한으로 줄이려 하였다. 편방향 구내 골 신장기와 스플린트를 이용하여 양악 골신장술을 시행하였다. 5일의 잠재기 후 매일 1mm의 골신장을 시행하였고 6주에서 8주간의 경화기를 둔 후, 골 신장기와 스플린트를 제거하였다. 골신장 길이는 각각 13mm와 15mm이었고, 특이할 만한 부작용은 관찰되지 않았다. 이에 본 교실에서는 상악신장을 바탕으로 양악을 신장시키는 새로운 술식을 보고하는 바이다.

• Proceedings of the Korean Society of Dyers and Finishers Conference
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• 2011.11a
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• pp.43-43
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• 2011

현대인들은 생활환경에서 발생하는 각종 미세먼지 등의 입자상 오염물질 뿐만 아니라 각종 VOCs 등의 가스상 오염물질과 곰팡이, 박테리아, 바이러스 등 생물학적 오염물질까지 생활공간 내의 공기환경은 점점 악화 되고 있으며 공기 정화 등의 필요성이 증대 되고 있다. 이에 본 연구에서는 닥 펄프와 활성탄이 주성분인 Sheet를 Corrugation 장치를 통해 편파형(골판지)으로 제작하고, 다시 다층 구조로 적층된 골판지 sheet을 제작한 후 이를 두께 방향으로 일정 폭(20mm이하)으로 절단하여 필터부품의 소자로 이용하는 활성탄 필터의 제조 및 그 특성을 확인하고자 하였다. 닥펄프/펄프와 무기물의 혼합비, 해리시간 등의 변화를 주어 샘플을 만들었고, 강도, 평활성, 생산성 향상을 위해 첨가보조제 선정을 하였다. 이렇게 제조된 필터의 물리적 특성을 알아보고자 인장시험을 실시하였고, 주사전자현미경을 통하여 필터의 평활성과 표면을 관찰하였고 흡착성능 및 기능성을 VOCs 방출량, 탈취율, 항균도, 곰팡이 저항성 등의 실험을 통하여 알아보았다.