수 종의 도재 수복물에 부착된 세라믹 브라켓의 전단접착강도와 파절양상에 열순환이 미치는 영향

강상욱,손우성,박수병,김성식 대한치과교정학회 2009 대한치과교정학회지 Vol.39 No.4

본 연구는 도재 수복물에 부착된 단결정 세라믹 브라켓의 전단접착강도와 파절양상에 열순환과 도재 수복물의 종류가 어떤 영향을 미치는지 알아보기 위해 시행되었다. 도재전장관에 사용되는 재료들 중 Ceramco 3, Empress II, Zi-ceram/Vintage ZR 세 가지를 선택하여 각 20개씩 총 60개의 시편을 원반형태(두께 2 mm, 직경 12 mm)로 제작하였다. 동일한 접착 술식으로 세라믹 브라켓을 부착한 후 열순환을 시행한 실험군과 시행하지 않은 대조군, 두 군으로 나누어 전단접착강도와 파절양상을 평가하였다. 열순환을 하지 않은 대조군의 전단접착강도는 Ceramco 3는 7.06 ± 1.76 MPa, Empress II는 7.55 ± 2.38 MPa 그리고 Zi-ceram/Vintage ZR은 7.19 ± 1.38 MPa로 추천되는 전단접착강도(6 - 8 MPa)에 적합한 강도를 보였으나 열순환을 시행한 실험군은 전단접착강도가 유의하게 감소하였으며(p < 0.05) 열순환 후의 전단접착강도는 Ceramco 3는 4.88 ± 1.00 MPa, Empress II는 5.46 ± 1.35 MPa 그리고 Zi-ceram/ Vintage ZR은 4.84 ± 1.01 MPa로 임상적으로 추천되는 것보다 다소 낮은 값을 보였다. 도재의 종류에 따른 전단접착강도에는 유의한 차이가 없었다. 파절양상은 대조군에서는 모두 브라켓 기저부와 접착제 사이에서 파절이 일어났으며, 실험군에서는 2개의 시편(Ceramco 3과 Zi-ceram/Vintage ZR군에서 각 1개)만이 접착제내 파절을 보였으며 28개의 시편은 브라켓 기저부와 접착제 사이에서 파절이 일어났다. 이상의 연구 결과에서 보았을 때 도재 수복물의 종류에 따른 차이는 없었으나 열순환에 의해 전단접착강도가 약화되므로 실제 임상에서 고려되어야 할 것이다. Objective: The purpose of this study was to investigate the effect of thermocycling and type of porcelain restoration on shear bond strength (SBS) and mode of failure of monocrystalline ceramic brackets. Methods: A total of 60 porcelain discs were made and divided into three equal groups as follows: Ceramco 3, IPS Empress II, Zi-ceram/Vintage ZR. ceramic brackets were bonded to the prepared porcelain surfaces in the same manner. Each group was divided randomly into two subgroups: thermocycled group and non-thermocycled group (control). All samples were tested in shear mode on an universal testing machine. Results: SBS of the non-thermocycled group was clinically acceptable (Ceramco 3: 7.06 ± 1.76 MPa, IPS Empress II: 7.55 ± 2.38 MPa, Zi-ceram/ Vintage ZR: 7.19 ± 1.38 MPa). But, SBS of the thermocycled group was significantly reduced (Ceramco 3: 4.88 ± 1.00 MPa, IPS Empress II: 5.46 ± 1.35 MPa, Zi-ceram/Vintage ZR: 4.84 ± 1.01 MPa, p < 0.05). There was no difference between the shear bond strength by type of porcelain restoration. All bonding failure occurred between bracket base and adhesive, except for 2 samples. Conclusions: The results of this study suggest that the type of porcelain restoration did not affect SBS, but thermocycling weakened SBS. Therefore, the effect of thermocycling should be considered when using ceramic brackets in practice.

복합재 티모센코 보의 새로운 해석법 제안

강병식,박중윤,홍성욱 金烏工科大學校 2000 論文集 Vol.21 No.-

This paper presents an exact dynamic element for composite Timoshenko beam, which is inherently subjected both to bending and torsional vibration. The coupling effect between bending and torsional vibrations is considered in the derivation of the exact dynamic element. Three examples are provided to validate and illustrate the proposed exact dynamic element matrix for composite Timoshenko beam.

급성 심근허혈에 의해 윤발된 승모판 폐쇄부전의 기전에 관한 실험적 연구

강덕현,송현,송재관,김현숙,이재환,임희영,이재원,박성욱,박승정,송명근 대한순환기학회 1999 Korean Circulation Journal Vol.29 No.8

두경부 종양세포주에 대한 Mithramycin A의 세포자멸사 유도성 및Cisplatin 항암작용 증가효과

이강대,손성환,박종욱,김영록,이봉주,김주연 고신대학교의과대학 2008 고신대학교 의과대학 학술지 Vol.23 No.1

Background and Objectives : Cisplatin (CP) is a major chemotherapeutic agent for head and neck cancer. However, cancer cells can get drug resistance through recovering the DNA damage by CP. Mithramycin A (MA) can inhibit gene expression of multidrug resistance gene 1, c-myc or h-ras. The goal of this study is to evaluate the therapeutic effect of MA alone and combination of MA and CP on head and neck cancer cell lines. Materials and Methods : Two head and neck cancer cell lines (AMC-HN4, AMC-HN7) were treated with MA. The cellular proliferation, apoptosis and protein expression were measured with XTT assay, FACS analysis, and western blotting, respectively after MA treatment in cell lines. In order to know the combination effect of MA with CP, the cancer cell lines were treated with MA, CP, and MA/CP combination, and cellular proliferation, apoptosis and expression of apoptosis-associated proteins were measured. Results : MA inhibited the proliferation of head and neck cancer cells and induce dapoptosis. Increase of caspase activation, PLC-?1 fragmentation and percent apoptosis by MA treatment was blocked by z-VAD-fms, but not blocked by N-Acetyl Cystein. Combination of MA and CP significantly inhibited cancer cell growth and increased apoptosis compared to MA and CP alone, and it also suppressed the expression of anti-apoptotic proteins such as XIAP and Mcl-1. Conclusions : The present study suggests that MA alone andMA/CP combination chemotherapy could be a potential regiment for the control of the head and neck cancer.

건물 산란계수를 이용한 비가시거리영역에서의 전파환경

강부식,김홍수,홍성욱 濟州大學校工科大學産業技術硏究所 1997 尖端技術硏究所論文集 Vol.8 No.1

In this paper, the scattered electric fields is computed to predict the shielding zone by analysing the effect of the reflected azimuth anlge at the building, and considering the path differences at observation point between the rays from origin and any point in the building. The scattering coefficients, which are applicable to the prediction of shielding zone, are computed and compared with measured one. We found that the scattering power become weak over 10 degree of the azimuth angle at which the scattering coefficient is lower than 40 dB. From this. the shielding zone can be estimated.

내시경적 점막절제술로 치험한 식도 과립상 세포종 1례

강혁주,김성욱,최석진,이중현,장재식,서영범,윤병구,박건욱,김성자,김용섭,강승완,이구,양창헌,이창우,김욱년,이광헌,서정일 동국대학교 의학연구소 2000 東國醫學 Vol.7 No.-

과립상 세포종은 Schwann 세포 기원으로 생각되며 인체에 비교적 드물게 발생한다. 과립상 세포종은 전신 어느 곳에서나 발견될 수 있으나 주로 혀, 구강, 피부 혹은 유방 등에서 호발하며 드물게 위장관에서 발견된다. 위장관에서는 식도에서 가장 호발하며 다음으로 위, 대장 순이다. 과립상 세포종은 대부분, 특히 위장관에서는 양성이며 소수의 악성 병변이 보고되었다. 이러한 이유와 함께 수술 전의 진단이 어렵기 때문에 과립상 세포종에 대한 근본적인 치료는 현재까지 외과적 절제술이다. 최근에 시도되는 치료방법들로는 내시경적 레이저 치료, 용종절제술, 내시경적 점막 절제술 등이 있다. 저자들은 상부 소화관 내시경검사를 시행하여 식도 과립상 세포종을 진단하고 내시경적 점막 절제술을 시행하여 합병증 없이 퇴원하여 현재 재발없이 경과 관찰중인 1례를 경험하였기에 보고하는 바이다. Granular cell tumors, which occur infrequently, are probably of Schwann cell origin. They can occur almost anywhere in the body but usually affect the tongue, oral cavity, skin, or breasts and are rarely found in the gastrointestinal tracts. The esophagus is the most frequent gastrointestinal site, followed by the stomach and the colon. Granular cell tumors are generally benign, especially in the gastrointestinal tract, some malignant lesions have been reported. For this reason, and also because preoperative diagnosis is difficult, the standard treatment for granular cell tumor has until now been surgical excision. In recent years, other therapeutic methods is endoscopic laser therapy (ELT), polypectiomy, endoscopic mucosal resection (EMR). We report a case of esophageal granular cell tumor which was diagnosed by an endoscopy and managed using an endoscopic mucosal resection without complication.

Alcaligenes latus의 배양방법에 따른 생분해성 플라스틱의 생산특성

박성연,조강현,최희식,류희욱,조경숙 이화여자대학교 환경문제연구소 1998 이화환경연구 Vol.2 No.-

생장과 동시에 poly(3-hydroxybutyrate, PHB) 를 체내에 축적하고, 값싼 당류인 sucrose를 이용할 수 있는 Alcaligenes latus의 생장과 PHB 생산을 최적화 할 수 있는 배양 조건에 대하여 연구하였다. 균주 생장과 PHB 생산성에 미치는 sucrose의 초기농도의 영향을 5L 발효조를 이용하여 회분식 배양 방법에 의해 조사하였다. PHB생산성은 sucrose농도가 10g/L에서 30g/L로 증가함에 따라 0.11에서 0.36g-PHB/L·h까지 증가하였고, 그 이상의 농도에서는 큰 변화없이 0.36∼0.39g-PHB/L·h에서 일정하게 유지되었다. 균주의 비증식속도는 sucrose 농도 증가함에 따라 증가하여 30g/L에서 최대값 0.44h()을 보였으며, sucrose의 농도가 30g/L을 초과하면 균주의 생장은 기질에 의해 저해 받았다. A. latus를 이용하여 대량으로 PHB를 생산하기 위해 유가식 배양과 반연속 유가식 배양을 수행하였다. 인산염 제한하에서 유가식 배양에 의해 얻은 PHB 생산성은 1.14g-PHB/L·h로, 인산염 제한없는 조건에서 얻은 PHB생산성(2.10g-PHB/L·h)에 비해서 훨씬 작았다. PHB함량은 영양소 제한에 관계없이 55∼60%이었다. 영양소 제한 없이 반연속 유가식 배양법에 의해 PHB생산성을 4.5∼4.8g-PHB/L·h까지 향상시킬 수 있었다. 평균 PHB 함량, 소비된 sucrose당 건조 균체중량 수율 및 PHB 생산 수율은 각각 60%, 0.48 및 0.32이었다. 그러므로, 생장과 동시에 PHB를 축적할 수 있는 A. latus를 이용하여 PHB를 생산할 경우, 반연속 유가식 배양법은 높은 PHB생산성을 얻을 수 있는 유망한 배양법임을 알 수 있다. Optimum conditions for cell growth and poly(3-hydroxybutyrate, PHB) biosynthesis of Alcaligenes latus, which can accumulate PHB simultaneously in associated with cell growth and grows well on a cheap carbon source such as sucrose, were investigated. The effect of initial sucrose concentration, ranged from 10 to 50g/L, on the cell growth and PHB accumulation were studied by a batch culture in a 5L fermentor. PHB productivity was increased from 0.11 to 0.36g-PHB/L·h with increasing sucrose concentration up to 30g/L, and it was fairly constant between concentrations of 30g/L and 50g/L. The maximum specific growth rate, 0.44h(), was obtained at 30g-sucrose/L, and the growth was inhibited at concentrations of sucrose over 30g/L. A. latus was also cultivated to attain high PHB productivity by fed-batch or semicontinuous fed-batch culture techniques. PHB productivity by a fed-batch culture under phosphate limitation(1.14g-PHB/L·h) were smaller than that without nutrient limitation(2.10g-PHB/L·h). but there is no significant difference of PHB content(55∼60%) obtained in both culture. By a semicontinuous fed-batch culture without nutrient limitation, high PHB productivity could be obtained as 4.5∼4.8g-PHB/L·h. The average PHB content, the yield of dry cell weight, and the yield of per consumed sucrose were 60%, 0.48, and 0.32, respectively. These results suggest that the semicontinuous fed-batch culture technique is one of promising methods to achieve high PHB productivity by A. latus.

MIN-MAX SOFM과 객체 분석을 이용한 얼굴 검출 알고리즘 개발

하성욱,강대성,권기항 東亞大學校 附設 情報通信硏究所 1998 情報通信硏究所論文誌 Vol.6 No.1

This paper proposes a face region detecting algorithm in stream images. The main limitation of current face detection researches is the front face detection. But, the face detection in stream images needs to extract features in various angles. Current algorithms also are not enough to be applied to the real world from the several limited arguments as uniform luminous intensity, simple background, etc. This reserch suggests a detection algorithm of stream face images which is regardless of these limit arguments. The firs stage supports a proposition of MIN-MAX SOFM(self organizing feature maps) by applied MIN-MAX theory in SOFM which is independent on luminous intensity. After the first stage, the small regioin removing algorithin is processed for loss regions in SOFM output mode. We propose a histogram object analysis method which selects speedy recognized regions and a frame based moving detection method by moving real images.

건물 산란계수를 이용한 비가시거리 영역에서의 전파환경

홍성욱,강부식,김흥수 濟州大學校 産業技術硏究所 1997 산업기술연구소논문집 Vol.8 No.1

In this paper, the scattered electric fields is computed to predict the shielding zone by analysing the effect of the reflected azimuth anlge at the building, and considering the path differences at observation point between the rays from origin and any point in the building. The scattering coefficients. which are applicable to the prediction of shielding zone. are computed and compared with measured one. We found that the scattering power become weak over 10 degree of the azimuth angle at which the scattering coefficient is lower than 40 dB. From this, the shielding zone can be estimated.

유전 알고리즘을 이용한 영상 영역화

하성욱,강대성 東亞大學校 大學院 1997 大學院論文集 Vol.22 No.-

This paper proposes a new image segmentation algorithm using GA(genetic algorithm) to solve the vigilance parameter problem of ACT(adaptive clustering technique). The solution of GA can be moving because of stochastic reinsertion and suffer from the premature convergence problem owing to deficiency of individuals before finding the optimal solution. We also suggest the GBR(great best reinsertion) technique to cope with the problem. GBR selects the individual in the child pool that has the fitness value superior to that of the individual in the parents pool. The experimental results show the proposed algorithm gives better performance than the ACT ones in Gaussian noise environments.