• The korean journal of orthodontics
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• 제31권2호통권85호
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• pp.173-185
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• 2001

The orthodontic osseointegrated titanium implant, a kind of intraoral skeletal anchorage can be an alternative to tooth-borne anchorage, in case that the conventional tooth-borne anchorage is not available or the anchorage is critical. This study was conducted to elucidate the effect of early loading on the osseointegration of the orthodontic titanium implant and the healing process of the impaired bone at the site of implant after removing it. In two adult beagle dogs24 osseointegrated titanium implants were inserted into the alveolar bone, with 12 implants placed in each dog. In dog1, 6 out of 12 implants were loaded with 200-300gm of force immediately after placing, and the remaining 6 implants were not loaded for 4weeks. In dog2, all 12 implants had healing period of 4weeks, and then were loaded with 200-300gm of force for another 4weeks. Following an observation period of 4 and 8 weeks, the animals were sacrificed. Then the implants and the surrounding bone of dog1 and dog2 were removed, respectively. Undecalcified sections along the long axis of implant were made and the degree of osseointegration was examined under the light microscope. The results were as follows. 1. In the histologic features of tissues around implants anchored in dog1, there was no difference between immediately loaded implants and unloaded implants. Immature woven bone was ingrowing into the thread spaces from the original compacta and in direct contact with the implant surface in part. 2. The premature loading just after 4weeks healing period did not halt the progress of the osseointegration between bone and implant surface. The woven bone around the implants was maturing into the lamellar bone which resembled the structure of the original compacta at the end of 8weeks observation period. 3. Most implants with the inflammed surrounding mucosa were lost or mobile. The mobile implants were encapsulated by fibrous connective tissue which separated the implant surface from the bone. 4. The impaired bone at the site of the implant failed to anchor was showing recovery without inflammatory reaction 2weeks after removing, with the immaure woven bone lined by active osteoblasts and osteoid. Based on the results of this study, the integration of this orthodontic implant seemed to be impaired by the inflammation of the tissue surrounding the Implant rather than by early loading on implant, and increased with time lapsed after placing the implant. The use of implant described in this report can be recommended as an orthodontic anchorage unit immediately after insertion under the careful control of orthodontic force applied and plaque.

• Clinical and Experimental Pediatrics
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• 제53권3호
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• pp.314-322
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• 2010

Purpose : Through a clinical and retrospective analysis of pediatric patients who visited the Regional Emergency Medical Center of Masan Samsung Hospital from January 2007 to December 2008, we characterized pediatric and adolescent emergency patients to improve emergency care in future. Methods : We reviewed the medical records of 14,065 pediatric patients below 19 years of age. Results : The male to female ratio was 1.5:1, and the most common age group was less than 3 years (49.6%). The peak month was May (10.0%), the peak day of the week was Sunday (24.7%), and the peak time of day was 20:00-0:59 (8.5%). There was no difference in the number of visits per day based on weather (sunny, rain [below 10 mm per day], snow, and fog) or daily temperature difference; however, visits increased on sandy, dusty days and decreased on rainy days with more than 10 mm of rain per day. Based on the international classification of disease (ICD)-10 system, the most common disease code was code R (symptoms, sign, and abnormal clinical laboratory finding) (31.5%), and the most common symptom was fever (13.1%). Final outcomes were discharged (73.8%), admitted (25.7%), transferred (0.4%), and expired (0.1%). In adolescent patients aged 15-9 years, the most common disease code was Injury & Poisoning (code S&T, 36.9%); the most common symptom was abdominal pain (9.6%). Conclusion : Pediatric patients visiting the emergency center were most likely to be male and under 3 years of age and to visit between 20:00 and 21:00 on Sundays and in May, and the most common symptom was fever. Differences between adolescents and pediatric patients showed that adolescents had a higher visiting rate with abdominal pain and a larger temperature difference.

• Journal of Periodontal and Implant Science
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• 제23권3호
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• pp.535-563
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• 1993

New techniques for regenerating the destructed periodontal tissue have been studied for many years. Current acceptable methods of promoting periodontal regeneration alre basis of removal of diseased soft tissue, root treatment, guided tissue regeneration, graft materials, biological mediators. Platelet-derived growth factor (PDGF) is one of polypeptide growth factor. PDGF have been reported as a biological mediator which regulate activities of wound healing progress including cell proliferation, migration, and metabolism. The purposes of this study is to evaluate the possibility of using the PDGF as a regeneration promoting agent for furcation involvement defect. Eight adult mongrel dogs were used in this experiment. The dogs were anesthetized with Pentobarbital Sodium (25-30 mg/kg of body weight, Tokyo chemical Co., Japan) and conventional periodontal prophylaxis were performed with ultrasonic scaler. With intrasulcular and crestal incision, mucoperiosteal flap was elevated. Following decortication with 1/2 high speed round bur, degree III furcation defect was made on mandibular second(P2) and fourth(P4) premolar. For the basic treatment of root surface, fully saturated citric acid was applied on the exposed root surface for 3 minutes. On the right P4 20ug of human recombinant PDGF-BB dissolved in acetic acid was applied with polypropylene autopipette. On the left P2 and right P2 PDGF-BB was applied after insertion of ${\beta}-Tricalcium$ phosphate(TCP) and collagen (Collatape) respectively. Left mandibular P4 was used as control. Systemic antibiotics (Penicillin-G benzathine and penicillin-G procaine, 1 ml per 10-25 1bs body weight) were administrated intramuscular for 2 weeks after surgery. Irrigation with 0.1% Chlorhexidine Gluconate around operated sites was performed during the whole experimental period except one day immediate after surgery. Soft diets were fed through the whole experiment period. After 2, 4, 8, 12 weeks, the animals were sacrificed by perfusion technique. Tissue block was excised including the tooth and prepared for light microscope with H-E staining. At 2 weeks after surgery, therer were rapid osteogenesis phenomenon on the defected area of the PDGF only treated group and early trabeculation pattern was made with new osteoid tissue produced by activated osteoblast. Bone formation was almost completed to the fornix of furcation by 8 weeks after surgery. New cementum fromation was observed from 2 weeks after surgery, and the thickness was increased until 8 weeks with typical Sharpey’s fibers reembedded into new bone and cementum. In both PDGF-BB with TCP group and PDGF-BB with Collagen group, regeneration process including new bone and new cementum formation and the group especially in the early weeks. It might be thought that the migration of actively proliferating cells was prohibited by the graft materials. In conclusion, platelet-derived growth factor can promote rapid osteogenesis during early stage of periodontal tissue regeneration.

• Journal of Chest Surgery
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• 제37권3호
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• pp.201-209
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• 2004

Extracorporeal life support (ECLS) system is a device for respiratory and/or heart failure treatment, and there have been many trials for development and clinical application in the world. Currently, a non-pulsatile blood pump is a standard for ECLS system. Although a pulsatile blood pump is advantageous in physiologic aspects, high pressure generated in the circuits and resultant blood cell trauma remain major concerns which make one reluctant to use a pulsatile blood pump in artificial lung circuits containing a membrane oxygenator. The study was designed to evaluate the hypothesis that placement of a pressure-relieving compliance chamber between a pulsatile pump and a membrane oxygenator might reduce the above mentioned side effects while providing physiologic pulsatile blood flow. The study was performed in a canine model of oleic acid induced acute lung injury (N=16). The animals were divided into three groups according to the type of pump used and the presence of the compliance chamber, In group 1, a non-pulsatile centrifugal pump was used as a control (n=6). In group 2 (n=4), a single-pulsatile pump was used. In group 3 (n=6), a single-pulsatile pump equipped with a compliance chamber was used. The experimental model was a partial bypass between the right atrium and the aorta at a pump flow of 1.8∼2 L/min for 2 hours. The observed parameters were focused on hemodynamic changes, intra-circuit pressure, laboratory studies for blood profile, and the effect on blood cell trauma. In hemodynamics, the pulsatile group II & III generated higher arterial pulse pressure (47$\pm$ 10 and 41 $\pm$ 9 mmHg) than the nonpulsatile group 1 (17 $\pm$ 7 mmHg, p<0.001). The intra-circuit pressure at membrane oxygenator were 222 $\pm$ 8 mmHg in group 1, 739 $\pm$ 35 mmHg in group 2, and 470 $\pm$ 17 mmHg in group 3 (p<0.001). At 2 hour bypass, arterial oxygen partial pressures were significantly higher in the pulsatile group 2 & 3 than in the non-pulsatile group 1 (77 $\pm$ 41 mmHg in group 1, 96 $\pm$ 48 mmHg in group 2, and 97 $\pm$ 25 mmHg in group 3: p<0.05). The levels of plasma free hemoglobin which was an indicator of blood cell trauma were lowest in group 1, highest in group 2, and significantly decreased in group 3 (55.7 $\pm$ 43.3, 162.8 $\pm$ 113.6, 82.5 $\pm$ 25.1 mg%, respectively; p<0.05). Other laboratory findings for blood profile were not different. The above results imply that the pulsatile blood pump is beneficial in oxygenation while deleterious in the aspects to high pressure generation in the circuits and blood cell trauma. However, when a pressure-relieving compliance chamber is applied between the pulsatile pump and a membrane oxygenator, it can significantly reduce the high circuit pressure and result in low blood cell trauma.

• The Journal of Korean Academy of Prosthodontics
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• 제36권6호
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• pp.900-913
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• 1998

Despite of technical difficulties, the combination of occlusal projection and densitometric digital analysis may ultimately provide a means of detection of subtle bone loss at the facial and lingual side of dental implant (Oblique occlusal view is more useful for $ITI^{(R)}$ dental implant due to its contour of shoulder as like tulip flower). In this study, conventional periapical projections of x-ray beam had shown more high sensitivity to detect the bony defects than oblique occlusal projections in alveolar crest obscured by dental implants or not, even if the difference was not statistically significant. Unlike conventional periapical projections. occusal projections combined with densitometric digital analysis technique may provide a means for detection of subtle bone change at the all around of implants without obscuring effect by implant itself. Although the results from this in vitro study were performed under limited circumstances, these results might afford more possibility and versatile modality of diagnosis options to clinician in the implant practice.

• Proceedings of the Korean Society of Embryo Transfer Conference
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• 한국수정란이식학회 2002년도 국제심포지엄
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• pp.106-106
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• 2002

미토콘드리아는 세포내의 에너지대사에서 중요한 역할을 수행하는 세포내 소기관이며, 자체의 유전물질이 모계를 통해 유전되는 특징을 가지고 있다. 포유류 초기 배아의 발생과정에서 미토콘드리아의 역할과 기능에 대한 연구는 미진한 상태이다. 본 연구에서는 생쥐 초기 배아의 발생과정에서 관찰할 수 있는 미토콘드리아 미세구조의 변화 양상을 살펴보고, 이와 초기 배아의 발생 능력과의 관련성을 밝혀보고자 하였다. 과배란 유도된 ICR 생쥐로부터 배란된 난자와 2-세포기 배아를 수획하여 76 배양액으로 포배기까지 체외배양하면서, 각각의 발생단계에 따라 시료를 수획하였다. 미토콘드리아 미세구조의 변화는 일반적인 투과전자현미경방법(TEM)을 이용하여 관찰하였다. 미토콘드리아의 미세구조는 배란 난자에서 4-세포기 배아까지는 구형이고 크리스타가 발달하지 않은 원시형태였지만, 포배기로 발달함에 따라 크리스타가 발달된 막대형의 전형적인 미토콘드리아로 분화됨이 관찰되었다. 체외배양 중에 발생이 지연되거나 정지된 배아에서 관찰한 미토콘드리아의 미세구조는 공포화 (vacuolization), 크리스타 발달 지연, 손상된 미토콘드리아의 세포막 등과 같은 비정상적인 변형을 관찰할 수 있었다. 또한, 극체에 존재하는 미토콘드리아의 미세구조는 정상적인 핵내의 유전자와의 상호작용이 없어 미분화 상태로 포배기까지 유지되는 것을 관찰하였다. 이상의 결과를 통해 미토콘드리아의 정상적인 분화 과정이 초기 배아의 발생능력과 관련되어 있음을 알 수 있었으며, 포유류 초기 배아의 체외배양시스템을 개선하는데 미토콘드리아 미세구조의 관찰과 변화에 대한 고려가 있어야 될 것으로 생각된다. buffer A 용액으로 세척하여 유리 petri dish의 바닥에 부착된 macrophage만을 cell scraper로 분리하였다. 분리한 macrophage는 0.5-1 $\times$ $10^{6}$ cells/$m\ell$가 되게 조정하여, IL-I 을 0.001, 0.01, 0.1 또한 1 ng/$m\ell$를 첨가하여 농도에 따른 효과를 조사하였고, 각각 24, 48, 72, 96 또한 120시간을 배양하여 시간에 의한 효과도 실시하였다. 각 배치구에서 얻어진 배양액은 TGF-$\beta$를 조사하기 전까지 -2$0^{\circ}C$에 동결 보존하였다. TGF-$\beta$의 측정은 TGF-$\beta$ kit(promega, USA)를 이용하여 실시하였으며, 통계학적 분석은 Anova test를 Statview program을 이용하여 분석하였다. 시험의 결과 대조구에 비해 IL-I 첨가구는 2-3배의 TGF-$\beta$생산을 보였으며, 배양시간에 따른 생산은 시간이 지남에 따라 약간 상승하는 경향을 보였으나, 유의적인 차이를 보이지는 않았다. 또한 IL-I의 농도에 따른 생산의 변화는 IL-I의 농도에 따라 약간의 차이를 보였고 유의적인 차이는 인정되지 않았다. 임신 및 비임신의 경우 임신우의 비장 macrophage가 비임신보다는 약간 상승하는 거스로 나타났다. 이상의 결과로 볼 때 IL-I $\alpha$ 는$\bet

• Journal of the korean academy of Pediatric Dentistry
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• 제27권2호
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• pp.344-350
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• 2000

Incidence of crown-root fracture due to traumatic injury, have been reported 3% in the permanent dentiton, 2% in the deciduous dentition. There are two treatment methods for crown-root fractured teeth with pulp exposure, when the fracture line was located under the alveolar crest. One way is the extrusion by orthodontic force the other way is intra-alveolar transplantation which occlusally repositioning of apical fragment in the alveolar socket. Since intra-alveolar transplantation has introduced in 1970s, it was practiced as alternative to orthodontic extrusion. As the result, this method may thoughted that had a good prognosis. As a result of trauma, completely crown-root fracture was occured in the maxillary right central incisor in this case. We couldn't reposition the deepest fracture line above the alveolar crest by the conventional surgical extrusion, because apical fragment was too short. Thus, after extraction of apical fragment, we repositioned it to the socket following demineralized freezed dried bone graft, which possible to support the apical fragment. At the 15-month recall examination, the root still showed normal mobility and there was not observed any in flammatory or replacement root resorption in the periapical radiograph.

• Journal of Chest Surgery
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• 제39권10호
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• pp.765-769
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• 2006

Background: Nuss procedure is a minimally invasive technique for correcting the pectus excavatum. But there are some limitations of correcting the complex anomaly or grown-up patients. Material and Method: we retrospectively reviewed 135 consecutive patients who underwent repair of pectus excavatum by the Nuss procedure and its modifications between November 1999 and December 2004. We analyzed the computed tomography, age on operation, operative technique, and complications. Result: We operated 135 patients of pectus excavatum during 62 months. Total number of operations about Nuss procedure is 216, including bar removal procedure of 64 cases, redo Nuss procedures of 47 cases. We modified the point of bar insertion to the hinge point, made a shoulder in the bar to prevent a displacement. And then we changed the fixation material from Vicryl to steel wire. If the patients are old, we retract the sternum during bar rotation and fixation. Until 2002, the number of redo Nuss operations were 17, complications were 23. but, after modifications, the number of redo Nuss operation were 0, complications were 2. Conclusion: This result indicates that our modifications of Nuss operation is effective, and could decrease the number of redo Nuss operation and complications.

• Journal of the Korea Concrete Institute
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• 제23권3호
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• pp.265-272
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• 2011

Even though concrete is the most important material for building structures, its intrinsic gray color degrades urban esthetics. In order to improve this problem, coloring methods of mixing pigment in concrete batch and painting the surface of concrete surface have been tried. However, applications of the coloring methods in construction field are difficult due to high cost and low durability. Recently, acid stain agent is emerging as a new coloring method for concrete. It is able to apply a remarkably thin colored layer on a concrete surface from chemical reaction between acid and alkaline solutions. This study has examined the changes and variations of the surface layer of mortar specimen from chemical reaction of acid stained agents. The colors were changed into natural irregular stains according to aging. After the staining, no shape change was found from visible inspections. Microstructure of the colored surface applied with acid stained agent was much rougher than that of original mortar. When the colored layer was compared to original surface, crystals of hydrate such as $Ca(OH)_2$ and C-S-H gel were observed. Surface hardness was same or slightly higher in the colored layer. The value of pH was reduced by approximately 10%, weight contents of elements such as Ca, Si, and Al were low. In the chemical composition of the colored layer, the non-cement based elements of Mn, Cr, and Cu increased. Also, Fe and alkali elements of K and Na increased.

• Journal of the Microelectronics and Packaging Society
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• 제4권1호
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• pp.1-12
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• 1997

본 연구에서는 용액성장법에 의해 양자 입자로 구성된 CdS 박막을 슬라이드 유리기 판위에 성장시키고 이들의 구조적 광학적 특성에 대하여 연구하였고 이들 결과를 토대로 용 액성장법으로 성장된 CdS 박막의 양자 사이즈 효과에 대하여 연구하였다. 성장시간은 1, 3, 10, 20분이었고 성장온도는 75$^{\circ}C$였다. X-선 회절 분석결과 본 연구에서 합성된 CdS 박막은 hexagonal상의 결정구조를 갖는 것으로 나타났고 성장시간에 따라 막의 투께는 61~195nm, 입자사이즈는 8.5~22.5nm로 나타났다. 광에너지 변화에 따른 투과도 측정결과 본 연구의 CdS 시료는 성장시간에 따라 에너지 밴드갭이 2.43~2.51 eV로 나타나서 벌크 CdS의 에너 지 밴드갭인 2.42 ev보다 높은 에너지 밴드갭을 갖게 되어 양자 사이즈 효과에 의한 blue shift 현상이 용액성장법에 의해 합성된 CdS 시료에도 존재한다는 것이 밝혀졌다 그리고 이 같은 용액성장법으로 성장된 CdS에 대해 최초로 수행된 Raman 산란 실험결과 이성장방법 으로 성장된 CdS에는 1TO, E2, 1LO 포논 모드가 존재함을 알수 있었고 또한 입자 사이즈 감소에 의한 1LO포논 모드의저주파수 shift 현상 즉 포논 모드의 softening 현상이 있음이 밝혀졌고 softening은 최대6.2%까지 발생하였다. 이와같은 높은 softening은 본연구의 CdS 박막 내 양자 입자의 입도가 작은것에 기인하는 것으로 밝혀졌다. 또한 본 CdS 시료의 양 자 사이즈 효과의 결과로 1TO 포논도 나타났는데 이 1TO 포논과 E2 포논의 Raman shift 는 성장시간 즉 막의 두께와는 무관한 것으로 나타났다.행렬모형(二重比例行列模型)을 이용하여, 산업구조의 변화로 인한 직업별 인력수요 변화가 충분히 고려되도록 하였다. 전망의 결과에 따르면 향후 우리 경제는 지식기반경제(knowledge-based economy)로 이행하고 있다고 볼 수 있다. 우선 산업구조면에서 지식집약적산업으로의 구조조정이 일어나게 되고 이에 따라 산업별 취업구조에서도 고기술산업의 취업준비중이 급속히 증가하게 된다. 직업별 취업분포에 있어서도 전문기술직 행정관리직 등의 고숙련 사무직의 비중은 크게 증가하는 반면 생산관련직과 농림어업직의 비중은 감소하게 된다. 이처럼 경제가 지식집약화되어 감에 따라 고학력자에 대한 수요는 지속적으로 증가하지만 현재 적절한 인력양성과 공급이 이루어지지 않고 있어 향후 기술이나 기능에 따른 수급부일정(需給不一政)(skill mismatch)현상이 매우 심해질 것으로 보인다. 따라서 앞으로의 인력정책에서 가장 주안점을 두어야 할 부분은 첨단기술산업과 관련된 인력의 양성에 있다고 하겠다.2시간까지 LPDG용액은 MEC용액보다 비교적 나은 회복을 보였고 재관류 3일과 7일의 폐기능 평가에서 두 용액 모두에서 폐기능의 점차적 소실을 보였으며 이는 병리조직검사에서 보듯이 폐혐에 의한 외적인 요소라고 생각되며 따라서 LPDG용액은 허혈재관류손상 방지 및 급성폐렴 등 염증을 잘 관리한다면 20시간 이상 LPDG용액의 안전한 폐보존의 가능성 을 얻을 수 있었다.ic 형태로 외래유전자가 발현되었지만 대조구에서 87.0% (26/30개) 배반포기가 $\beta$-Gal 활력을 보인 반면, G418 처리구에서는 모든 배반포기가 $\beta$-Gal 활력을 보였다 (P<0.05). 그러나 대조구 및 G418 처리구의 ICM