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티타늄 상에 강유전성 barium titanate 박막 형성과 분극처리에 의한 유사체액 내에서의 calcium phosphate 생성 증진
박영준,이용렬,황규석,김은주,임용무,이기헌 대한치과기재학회 2001 대한치과재료학회지 Vol.28 No.2
This study was performed to fabricate a ferroelectric barium titanate (BaTiO₃, BTO) thin film on Ti substrate and to evaluate the effect of poling treatment for the improvement of calcium phosphate (Ca-P) formation. BTO thin-film was spin-coated on Ti substrate by dipping-pyrolysis technique using coating sol obtained by mixing Ba-naphthenate and Ti-naphthenate as starting substances. Pre-heating temperature of the BTO thin film was performed at 500℃ because organic-solvent was completely volatilized without any crystal growth, and the final heat treatment was performed at 600, 650, 700, 750, 800, 850℃, respectively. By repeating the coating and pre-heating procedure gor 20 times, homogeneous thin film of 0.7㎛ thickness could be fabricated, and it performed well during the poling treatment without breakdown. The final heating treatment of the BTO thin film at 750℃ produced a homogeneous crystalline structure without heterogeneous TiO₂formation, which was confirmed by field emission scanning electron microscope (FE-SEM) and X-ray diffraction analyser (XRD). An average grain size of 20∼30 ㎚ were confirmed by SEM observation. The final heat-treated BTO thin-films were polarized (Ep = 5 V/㎛) from 160℃ to 25℃ in heating chamber for 2 h. The negatively poled BTO thin film (N-BTO), non-poled BTO thin film (BTO), Ti substrate (Ti), and 600℃ heat-treated Ti (Ti-O) were immersed in SBF and Eagle's MEM solution for 15 days at 37℃. After the immersion period, the morphological and compositional changes of the surfaces were investigated using a FE-SEM and an energy dispersive X-ray spectrometer (EDX). After immersion in simulated body fluid (SBF), sodium chloride (Nacl) crystals were formed on Ti, Ti-O, and BTO surfaces due to anion adsorption (Cl), while Ca-P crystals were formed on N-BTO surfaces. We assumed that rapidly adsorded cations (Ca²□ ions) on the negatively charged surface at the initial stage acted as nuclei for the formation of Ca-P crystals. In MEM, sodium chloride (NaCl) was formed on Ti, and Ca-P layer including NaCl was formed on Ti-O. Weak and sparse Ca-P layers were formed on BTO, while thick, homogeneous, and dense Ca-P layer was formed on N-BTO, which was confirmed by FE-SEM and EDX. These results demonstrated that introducing a N-BTO on Ti is an effective method for the improvement of Ca-P formation in SBF and MEM. In conclusion, negatively charged ferroelectric BTO thin-film on Ti would improve the possibility of implant osseointegration.
강유전성 BaTiO₃의 분극처리에 의한 유사체액 내에서 Calcium Phosphate 생성
송종은,김은주,황규석,임용무,박영준 대한치과기재학회 2000 대한치과재료학회지 Vol.27 No.4
Barium titanate (BaTiO3; BTO) has wide application in industry, particularly in the manufacturing of dynamic random access memory chips, electro-optical switches, optical modulators, shutters, optical mixers, and sensors, owing to its ferroelectric and piezoelectric properties after poling treatment. There has recently been considerable interest in the properties of its role in osseointegration. In this study, we investigated the possibility of treating BTO by poling to improve osseointegration by examining the calcium phosphate (Ca-P) crystal growth behavior on the poled and non-poled BTO surfaces in simulated body fluids (SBF). The BTO samples were sintered at 1350℃ for 2 h in air, producing an average grain size of 7 ㎛, which were confirmed by SEM observation. The sintered BTO samples were then polarized (Ep=5 kV/cm) from 160℃ to 25℃ in a Si oil bath for 2 h. The poled and non-poled BTO samples were immersed in 1.5 SBF for 15 days, or 30 days at 37℃. After the immersion period, the morphological and compositional changes of the surface of the immersed BTO specimens were investigated using a field emission scanning electron microscope (FE-SEM) and an energy dispersive X-ray spectrometer (EDX). Qualitative analysis was then performed using fourier transform infrared (FTIR) analysis. Weak and coarse Ca-P crystals had grown on the surface of the non poled BTO, while a marked difference in the Ca-P forming pattern was visible for the poled BTO, showing the negatively charged surface induces a Ca-P layer more easily. We assumed that rapidly adsorbed cations (Ca2+ ions) on the negatively charged surface at the initial stage acted as nuclei for the formation of Ca-P crystals, while no nuclei would be available on the positively charged surface, due to the fact that sodium chloride (NaCl) crystals were formed owing to anion adsorption (Cl ions). In summary, these results demonstrate that poling the ferroelectric BTO surface negatively the possibility of implant osseointegration.
정응기,이기환,원용재,박향미,전남수,최준호,구연충,한창덕,은무영,김태산,남민희 Plant molecular biology and biotechnology research 2005 Plant molecular biology and biotechnology research Vol.2005 No.
This study was conducted to investigated the major characteristics of genetically modified rice of "Milyang 204" originated from Dongjinbyeo compared to a non-transgenic rice varieties Dongjinbyeo and Junambyeo. Basta resistant transgenic rice lines carrying bar gene produced by the Yeongnam Agricultural Research Institute were evaluated for their agronomic characters. The transgenic Japonica rice of "Milyang 204" showed inferior phenotypic traits compared to a non-transgenic rice variety Dongjinbyeo and Junambyeo. On the basis of UPOV (Union Internationale Pour la Protaection des Obtentions Vegetables) and NSMO(National Seed Management Office) the transgenic "Milyang 204" showed difference in some traits out of some agronomic traits, such as leaf color, angle of flag leaf, number of spikelets, culm length, white core and white belly compared to the nontransgenic varieties rice.
성인 여성에서 혈청 Osteoprotegerin 농도와 골대사의 관련성
오기원 ( O Gi Won ),윤은주 ( Yun Eun Ju ),오은숙 ( O Eun Sug ),이은정 ( Lee Eun Jeong ),이원영 ( Lee Won Yeong ),백기현 ( Baeg Gi Hyeon ),강무일 ( Kang Mu Il ),박경창 ( Park Gyeong Chang ),박철영 ( Park Cheol Yeong ),최문기 ( Choe 대한내과학회 2004 대한내과학회지 Vol.66 No.1
목적 : Osteoprotegerin (OPG)은 최근에 알려진 사이토카인으로 파골세포의 분화와 활성화에서 중요한 역할을 하는 receptor activator of NF-κB ligand의 decoy receptor로 알려져 있다. OPG는 동물실험에서 파골세포 형성과정의 중요한 억제제이나, 인체의 혈청 OPG 농도와 여성의 골대사 상태의 관련성은 명확하게 알려져 있지 않다. 따라서 본 연구에서는 건강한 한국인 성인 여성에서 혈청 OPG 농도와 골밀도 Background : Osteoprotegerin (OPG) is a recently identified cytokine that acts as a decoy receptor for the RANK ligand. OPG has been shown to be an important inhibitor of osteoclastogenesis in animal models. The relationship between circulating OPG levels