타이타늄 임플란트와 상부구조물의 갈바닉 쌍의 전기화학적 특성

오근택,김명화,최병갑,김경남 大韓齒科器材學會 2003 대한치과재료학회지 Vol.30 No.1

For the aesthetic and functional restoration of edentulous patients, recently dental implants have been used widely. Dental implants and restorative alloys are required with the high corrosion resistance. Suprastructure and implant with different compositions, which are in electrical contact, may develop galvanic or coupled corrosion problems. Besides galvanic corrosion, crevice and pitting corrosion may occur in the marginal gap or the gap between dental implant assemblies. In this study, Ti implants, gold, silver-palladium, cobalt-chromium and nickel-chromium suprastructures were used to investigate their galvanic and crevice corrosion of suprastructure/Ti implant couples. Potentiodynamic and potentiostaic testing were performed in artificial saliva at 37℃. Potentiodynamic testing was carried out at the potential scan rate of 1 ㎷/sec and in the range of -600∼1600 ㎷(SCE). Potentiostatic testing such as open circuit potential and current densities at -250, 0 and 250 ㎷(SCE) was performed for 5000 seconds in artificial saliva. After electrochemical testing, the surface and cross-sectional morphologies of the samples were observed using optical microscopy. Potentiodynamic test results indicated that suprastructure/Tim implant couples exhibited the passive current density range of 0.5∼12 ㎂/㎠, Ti abutment/Tim implant and gold/Tim implant couples exhibited relatively low passive current density, Co-Cr/Tim implant couples the highest. Co-Cr and Ni-Cr/Tim implant couples showed the breakdown potentials of 700 and 570 ㎷(SCE), respectively. Open circuit potentials of silver, Ti abutment, gold, Ni-Cr and Co-Cr/Ti implant couples were -93.2±93.9, -123.7±58.8, -140.0±80.6, -223.5±35.1, and -312.7±29.8, respectively and stable according to immersion time. The couples exhibited cathodic current densities at -250 ㎷(SCE), especially, gold and silver alloys showed the high cathodic current densities of ±3.18 and ±6.63 ㎂/㎠, respectively. At 250 ㎷(SCE), Ti abutment/Ti implant couples exhibited the lowest current density of 9.48×10^-2 ㎂/㎠, and gold, Ni-Cr, Co-Cr and silver/Ti implant couples exhibited 0.313, 1.27, 5.60 and 8.06 ㎂/㎠, respectively. The couples exhibited relatively low current densities at 0 ㎷(SCE). The photographs after electrochemical testing showed crevice or pitting corrosion in the marginal gap and suprastructure surface. Although Co-Cr/Ti implant couples among the tested samples had the possibility of the galvanic corrosion, its degree was not significant.

국내 Human Immunodeficiency Virus(HIV) 감염자와 정상인의 면역학적 표지인자 비교연구

신영오,류재천,최병선,박용근 THE KOREAN SOCIETY FOR BIOMEDICAL LABORATORY SCINE 1995 Journal of biomedical laboratory sciences Vol.1 No.1

HIV감염자는 질병의 진전에 무관하게 감염 후의 경과시기에 따라서 CD4 T림프세포등 각종 면역상태를 나타내는 표지가 변한다. 따라서 HIV감염자의 질병진전을 예보하기 위하여서는 정기적으로 CD4등 각종표지를 측정하여 감염자의 질병상태를 monitoring하게 된다. 그러나 이러한 수치를 감염자관리에 적용하기 위하여서는 우리나라 일반인의 정상치를 파악하여 이를 지표로 해야하므로 국내정상인의 각종면역치에 대한 조사가 요구된다. 현재의 기준으로는 500이하로 떨어질 때에는 예방차원에서 AZT를 복용하게 되며 200이하로 떨어지면 질병의 유무에 관계없이 환자로 관리하게 된다. 본연구에서는 한국인 185명의 감염자와 140명의 비감염자에 대하여 정기적으로 CD4 및 CD8T 림프세포와 CD4/CD8비를 측정하였다. 시험은 Flow cytometer(Facstar)를 이용하여 각각의 CD 분자에 대한 모노크로날 항체를 이용하여 2중혈광색소염색방법으로 측정하였다. HIV감염자의 CD4-T림프세로 절대수 및 백분율은 각각 462 및 18.2%이었는 반면, CD8의 수치는 1,170 및 47.0%이었다. 또한 CD4/CD8비는 0.43이었다. 이와는 대조적으로 비감염자의 경우, 한국인의 CD4의 평균세포수는 886, 백분율은 32.9%이었으며, CD8 세포수는 730, 백분율은 26.8 그리고 CD4/CD8비는 1.31이었다. 외국인과 한국인과의 면역지표수치를 비교하였을 때에 CD4세포수와 백분율, CD8의 백분율에서는 현저한 차이가 없었으나 외국인 비감염자의 경우 CD4백분율이 43.6%, CD8 T림프세포의 절대수가 560으로 한국인과 약간의 차이가 있었다. 따라서 HIV감염자관리를 위한 면역지표측정시험에서의 각종수치의 정확한 해석을 위하여서는 한국인 비감염자수치를 고려해야할 것으로 판단된다. Several studies showed that the immunological factors such as CD4+ cell number, CD4%, CD8+ cell number and CD4/CD8 ratio and the serological factors such as β²-microglobulin(β²-MG), neopterin, soluble CD4, and soluble CD8 are related to the risk of development of AIDS. Especially, the CD4+ cell counts have been used to monitor progresson of HIV disease, to stratify, and to follow patients in clinical trials. Recently, the Centers for Disease Control and Prevention(CDCP) in USA has made the CD4+ cell count as a part of the classification of HIV disease. It is composed of 3 categories such as 1, 2, and 3 which asr ≥500/㎣, 200/㎣ ≥and <500/㎣, and < 200/㎣, respectively. In this study, to estimate the differences of immunological factors between HIV-infected and normal human groups in Korea, CD4+ T and CD8+ T cells, and the CD4/CD8 ratio were measured in 185 HIV-infected subjects and 140 healthy adult subjects. The lymphocyte subsets such as CD4+ T and CD8+ T were analysed by flow cytometer(FACStar) with two-color immunofluorescent stain using monoclonal antibodies such as anti-CD4 and anti-CD8 antibodies. The absolute numbers and percentages of CD4+ T and CD8+ T and the CD4/CD8 ratio of HIV infected persons were 462±277/㎣, 18.2±7.7%, 1,170±534/㎣, 47.0±10.6% and 0.43±0.26 whereas those of uninfected persons were 886±299/㎣, 32.9±7.0%, 730± 259/㎣, 26.8±6.4% and l.31±0.46(P<0.01). In addition, estimating the reference values of peripheral blood lymphocyte subsets of Korean, the absolute numbers and percentages of CD4+ T and CD8+ T and the CD4/CD8 ratio of 140 healthy adults persons were measured and compared with those of foreigners. The reference ranges of CD4+ T cells, CD8+ T cells, CD4%, CD8%, and the CD4/CD8 ratio and 1.31t0.46, respectively. The significant differences were not observed when compared with those of foreigners. However a little difference was observed in the percentages of CD4+ T and the absolute numbers of CD8+ T between the normal values of Korean and those of foreigners were 43.6±8.9%, 560±230/㎣. This result can also be useful as a basic data for the treatment and surveillance of HIV-infected patients in Korea.

상아질 접착제의 중합 시간 조절에 따른 복합레진의 중합 수축 방향의 변화

배지현,오명환,김창근,손호현,엄정문,조병훈,권혁춘 대한치과보존학회 2001 Restorative Dentistry & Endodontics Vol.26 No.4

The purpose of this study was to evaluate the effect of adhesive curing timing on the direction of polymerization shrinkage of light-curing composite resin. In this study, the curing times of adhesive and composite resin were measured by differential scanning calorimeter(DSC). 28 extracted human molars were embedded in clear resin and box-type cavities were prepared. Based on DSC data. the experimental teeth were divided into 4 groups. Group 1: no bond: Group 2: late curing: Group 3: Intermediate curing: Group 4: Early curing. After treating with adhesive, the buccal cavities were filled with Z-100 hybrid composite resin and the lingual ones were filled with AEliteflo flowable composite resin. The depressions at the surface were measured by surface profilometer, then the specimens were embedded in clear resin and sectioned. Impressions were obtained and used to get epoxy resin replicas. The epoxy replicas were gold-coated and observed under SEM. Average Maximum Gap(AMG), Gap Proportion(GP), Average Marginal Index(AMI) were used to compare the shrinkage gap of each group. The results were statistically analyzed using the Kruskal-Wallis One Way ANOVA, Student-Newman-Keuls method. The results of this study were as follows. 1. Average Maximum Gap. Gap Proportion, Average Marginal Index and depression at the surface of Z-100 hybride composite resin were smailer than those of AEliteflo flowable composite resin(P(0.05) 2. When the bonding between composite resin and tooth structure was strong, the shrinkage gap was small, and depression at the surface was deep(P<0.05). 3. In the well-bonded group. light-curing composite resin shrank toward bonded cavity wall. not toward light source. The result suggested that the direction of polumerization shrinkage was affected by the quality of bonding in the dentin-resin interface. The strong was the bonding between composite resin and tooth structure, the smaller was the gap and the deeper was the depression at the surface. Then the flow to compensate the polymerization shrinkage proceeded from surface to bonded cavity wall.

Docetaxel-loaded multilayer nanoparticles with nanodroplets for cancer therapy

Oh, Keun Sang,Kim, Kyungim,Yoon, Byeong Deok,Lee, Hye Jin,Park, Dal Yong,Kim, Eun-yeong,Lee, Kiho,Seo, Jae Hong,Yuk, Soon Hong Dove Medical Press 2016 INTERNATIONAL JOURNAL OF NANOMEDICINE Vol.11 No.-

<P>A mixture of docetaxel (DTX) and Solutol<SUP>®</SUP> HS 15 (Solutol) transiently formed nanodroplets when it was suspended in an aqueous medium. However, nanodroplets that comprised DTX and Solutol showed a rapid precipitation of DTX because of their unstable characteristics in the aqueous medium. The incorporation of nanodroplets that comprised DTX and Solutol through vesicle fusion and subsequent stabilization was designed to prepare multilayer nanoparticles (NPs) with a DTX-loaded Solutol nanodroplet (as template NPs) core for an efficient delivery of DTX as a chemotherapeutic drug. As a result, the DTX-loaded Solutol nanodroplets (~11.7 nm) were observed to have an increased average diameter (from 11.7 nm to 156.1 nm) and a good stability of the hydrated NPs without precipitation of DTX by vesicle fusion and multilayered structure, respectively. Also, a long circulation of the multilayer NPs was observed, and this was due to the presence of Pluronic F-68 on the surface of the multilayer NPs. This led to an improved antitumor efficacy based on the enhanced permeation and retention effect. Therefore, this study indicated that the multilayer NPs have a considerable potential as a drug delivery system with an enhanced therapeutic efficacy by blood circulation and with low side effects.</P>

치과용 합금의 부식 특성에 관한 연구

오근택,김명화,최병갑,김경남 大韓齒科器材學會 2002 대한치과재료학회지 Vol.29 No.1

For the aesthetic and functional restoration of edentulous patients, recently dental implants have been used widely. Dental implants and restorative alloys are required with the high corrosion resistance. Therefore, Ti and its alloys have been used as implant materials and gold, silver, Ni-Cr and Co-Cr alloys and dental restorative materials due to their high corrosion resistance. However, they can be corroded in the oral cavity that is very complicated environments. In this study, Ti G2 and G3, gold, silver, Co-Cr and Ni-Cr alloys were investigated for their corrosion resistances and phenomena. Potentiodynamic and potentiostatic tests(open circuit potential and current density at-250, 0 and 250 mV(SCE) were performed in artificial saliva at 37℃. Corrosion of gold and silver alloys did not occur in artificial saliva due to their i㎜unity in this environment. Co-Cr, Ni-Cr and pure Ti exhibited the high corrosion resistance by their own passivity. Gold, silver and Ti G2 exhibited the highest corrosion resistance, Ni-Cr alloy and Ti G3 did the relatively high corrosion resistance, and Co-Cr alloy did the low corrosion resistance. The open circuit potentials of gold, Ti G2, Ni-Cr and silver alloys were about 50, 20, 0 and -60 mV(SCE), respectively. The open circuit potentials of Ti G3 and Co-Cr decreased with the i㎜ersion time. In the potential loading of -250 mV, cathodic current flowed to all samples, although the absolute values were different. In the potential loading of 0 mV, cathodic current flowed to the others except for Co-Cr alloy. Ti G2 and Co-Cr alloys showed anodic current and the others cathodic current in the potential loading of 250 mV. If the pure Ti is used as dental implant in the oral cavity, gold and silver alloys are considered to minimize the adverse effects by galvanic corrosion, but the galvanic corrosion as well as the localized corrosion such as pitting or crevice corrosion can be occurred in Co-Cr alloy.

Sutterella faecalis sp. nov., isolated from human faeces

Byeong Seob Oh,JI-SUN KIM,유승엽,Seoung Woo Ryu,SEUNG-HWAN PARK,강세원,박잠언,Seung-Hyeon Choi,Kook-Il Han,Keun Chul Lee,Mi Kyung Eom,Min Kuk Suh,Han Sol Kim,Dong Ho Lee,Hyuk Yoon,김병용,이제희,Jung-SookLee,이주혁 한국미생물학회 2020 The journal of microbiology Vol.58 No.2

An obligately anaerobic, Gram-stain-negative, non-motile, non-spore-forming, and coccobacilli-shaped bacterial strain, designated KGMB03119T, was isolated from human faeces from a Korean. Phylogenetic analysis based on the 16S rRNA gene sequence revealed that the isolate was a member of the genus Sutterella and most closely related to Sutterlla wadsworthensis KCTC 15691T (96.8% 16S rRNA gene sequence similarity). The DNA G + C content of strain KGMB03119T was 58.3 mol% as determined from its whole genome sequence. Strain KGMB03119T was asaccharolytic, catalase-positive, oxidase- and urease-negative. Furthermore, the isolate was positive for alkaline phosphatase, leucine arylamidase, acid phosphatase, arginine arylamidase, alanine arylamidase, and glycine arylamidase. The major cellular fatty acids (> 10%) of the isolate were C18:1ω9c and C16:0. Methylmenaquinone-5 (MMK-5, 100%) was the predominant isoprenoid quinone in the isolate. Based on the phylogenetic, physiological, and chemotaxonomic characteristics, strain KGMB03119T represents a novel species, for which the name Sutterella faecalis sp. nov. is proposed. The type strain is KGMB03119T (= KCTC 15823T = NBRC 114254T).

Effects of Canine Serum Obtained from Different Estrus Cycle on In Vitro Maturation of Canine Oocytes

Oh, Hyun-Ju,Kim, Min-Kyu,Fibrianto, Yuda Heru,Jang, Goo,Kim, Hye-Jin,Hossein, M. Shamim,Kang, Sung-Keun,Lee, Byeong-Chun,Hwang, Woo-Suk 한국수정란이식학회 2004 한국수정란이식학회 학술대회 Vol.2004 No.1

Implementation of a Layered Testbench using SystemVerilog

Byeong-Deok Kim,Young-Jin Oh,Myoung-Keun You,Gi-Yong Song 대한전자공학회 2009 ITC-CSCC :International Technical Conference on Ci Vol.2009 No.7

This paper describes functional verification on adaptive FIR filter using SystemVerilog. SystemVerilog has characteristics of hardware description languages and hardware verification language by expansion of Verilog HDL. Adaptive filter is a kind of FIR filter using adaptive algorithm. In this paper, testbench-based verification environment which verifies the functionality of adaptive FIR filter has a layered structure and is implemented with SystemVerilog.

골내 고정 장치용 초내식성 스테인리스강 내식성 및 세포독성

오근택(Keun-Taek Oh),강국진(Kook-Jin Kang),손병화(Byeong-Hwa Sohn),박용수(Yong-Soo Park),김경남(Kyoung-Nam Kim) 대한치과재료학회 2004 대한치과재료학회지 Vol.31 No.2

대형 부유식 구조물의 구조설계 관련 Rule & Code 비교 및 절차 분석

오근원(Keun Won Oh),유병석(Byeong Seok Yu) 한국해양환경·에너지학회 2013 한국해양환경·에너지학회 학술대회논문집 Vol.2013 No.11