Calcium phosphate 결정 성장 최적화를 위한 Ti 표면의 BaTiO_3 박막 형성에 관한 연구

조진우,양홍서,박영준,황규석,송종은,이용렬 전남대학교 치과대학 2001 구강과학 Vol.13 No.2

This study was purposed to establish an optimized manufacturing process for a negatively charged ferroelectric thin flim on titanium substrate in order to develop a new implant system having the mechanical strength and bone forming ability. Ferroelectric materials show an alignment of positive and negative charges by poling treatment. Based on this property, this study was performed with the assumption that the Ca^2+ ions would be easily attracted on negatively charged surface and the attracted cation might behave as nuclei for bone-like crystal grownth in biological solutions. In order to have an osteoinducibility by the ferroelectric thin film coating, continuous and flawless crystalline thin film should be formed with ferroelectricity, and finally should be adequately poling treated. In this study, BaTiO_3 (BTO) was selected as a ferroelectric material. Before thin film coating process, most favorable poling condition was investiged with the evaluation of the difference in calcium phosphate (Ca-P) formation in simulated body fluid (SBF). Moreover, the parameters to form an optimum thin film were studied. Dense bulk BTO disks were fabricate using cold isostatic pressing(CIP) and sintered in air at 1300℃ for 2 hours. Sintered BTO disk was polished, and he crystallinity, microstructure, and ferroelectric characteristics were evaluated using an X-ray diffraction analysis (XRD), a field emission scanning electron microscope (FE-SEM), and an Impedance analyzer. To find the optimum poling condition for the calcium phosphate crystal formation, sintered bulk BTO specimens were treated with either of following poling conditions; 1) room temperature poling treatment [ polarizing field (Ep) = 25kV/cm, at 25℃ for 2 hours], 2) under Tc medium-temperaturepoling treatment (Ep=20kV/cm, from 85˚C to 25˚C for 2 hour), and 3) above Tc high-temperature poling were immesed in simulated body fluid (SBF) for 30 days, and the formation of calcium phosphate (Ca-P) layer n the surface was evaluated. The crystallinity, microstructure, and ferroelectric characteristic of BTO thin film were evaluated withthe variation of final heat treatment. It was performed after establishing the starting substance-solvent mixing ratio, coating times, and pre-heating temperature optimal to form continuous and flawless BTO thin film adequate for having ferroelectricity. Perparation of BTO thin film was made by dipping-pyrolysis technique using metal naphthenates as starting substances. BTO thin films was spin-coated on Ti substrate by dipping-pyrolysis technique using sol obtained by mixing Ba-naphthenate and Ti-naphthenate as starting substances. Pre-firing temperature of BTO thin film was performed at 450℃ because organic-solvent ws completely volatilized without any crystal growth, and the final heat treatment was performed at 600, 700 or 800℃, respectively. The results are as follows; 1. BTO disk sintered at 1300℃ for 2 hours showed average grain size of about 1㎛ and the relative dielectric constant at 1㎑ was abut 3000∼3500. 2. After immersing the sintered bulk BTO poled at respective conditions in SBF for 30 days, Ca-P layers were present on the negatively charged surfaces. In contrary, positively charged Bto surface did not show any noticeable charge of the surface microstructure after SBF immersion. 3. In he case of poling condition 1 and 2 treated with below Tc, Ca/P ratio showed a relatively low value of 1,.2∼1.5. While, in the case of poling condition 3 treated with above Tc, Ca/P ratio was 1.5∼1.67, which is similar to that of biological apatite. This phenomenon demonstrates that poling the BTO above the temperature of Tc is preferable for the Ca-P formation. 4. For thin film BTO coastin, the starting substance was prepared by an equimolar mixing of the Ba and Ti-naphthenate. Dilution of the starting substance with toluene was most appropriate at sol : toluene ratio of 5.2:4.8 Too thin sol produced porosity in film, and too thick sol resulted cracks in the film. By repeating the coating and pre-firing procedure 15 times, homogeneous film of 0.5㎛ thickness could be fabricated, and perfomed well during the poling treatment without breakdown. 5. The heat-treatmen of the BTO thin film at 700℃ produced a homogeneous crystalline structure without heterogeneous TiO2 formation. The BTO thin film heat-treated at 600℃ showed non-crystallinity and no ferroelectricity. Treatment at 800℃ produced heterogeneous TiO2 phase in the film, which is unfavorabe for having ferroelectricity by the distortion of the perovskite structure. The relative dielectic constant at 1 ㎑ was 152 and 112 by heat-treatment at 700 and 800℃, respectively. In summary, these results demonstrated that poling the ferroelectric B_aT_iO_3 surface negatively is effective for the formation of Ca-P layer in simulated body fluids. Poling condition at a temperature cooling from above Tc down to room temperature is most effective. By optimizing the method of BTO thin film coating on metal substrate for the formation of Ca-P layer, the data of this study might be applied for the manufacture of new bioactive implant system.

말라리아 환자 32예의 임상적 고찰

정용희,백일현,김태형,김영식,이우인,서환조 대한화학요법학회 2000 대한화학요법학회지 Vol.18 No.1

목적 : 삼일열 말라리아는 국내에서 1986년 이후에는 박멸된 것으로 알려졌으나 1993년 이후 증가하는 양상을 보이고 있다. 이에 말라리아의 임상적 고찰을 통하여 이 질환을 이해함에 있다. 방법 : 1991년 1월부터 1999년 10월까지 반복적 고열과 오한을 주소로 본 병원에 내원하여 말초혈액 도말검사에 의해 말라리아 감염으로 확진된 32예의 환자에 대해서 후향적으로 조사하였다. 결과 : 1991년부터 1999년 10월까지 총 32명의 환자의 연도별 발생빈도는 각각 1991년에 1명, 1996년에 1명, 1997년에 3명, 1998년에 13명, 1999년에 14명이었다. 월별발생빈도는 7월과 8월에 집중적으로 발생하였다.(46.9%) 환자의 거주지는 경기 연천과 파주에 주로 분포되었다(53.1%). 성별발생분포는 32예의 환자중에 여자가 5명, 남자가 27명으로 남자가 더 많았다. 발병연령은 22세에서 87세까지 분포되었고 20-30대에 많이 발생하였으며 20대가 가장 많았다. 군인 및 제대자가 17명(59.4%)에 해당하였으며, 제대자의 평균 제대후의 기간은 10개월 정도였다. 가장 흔한 임상증상은 발열 및 오한이었다.(100%) 비장종대 및 간장종대는 각각 26명(81.3%), 3명(9.4%)에서 관찰되었다. 검사실 소견은 평균적으로 WBC 5.317/㎕, 혈색소 12.5±7.1g/㎗, 혈소판 78,906.3±68391.4㎕, GOT/GPT 43.7±26.7/49.6±57.3 IU/ℓ, Total bilirubin 1.6±0.9㎎/㎗를 보였다. 말초혈액 도말검사상 모두 P. vivax였다. 치료는 hydroxychloroquine과 primaquine의 치료에 잘 반응하였다. 결론 : 말라리아는 7월과 8월에 한국에서 호발하는 중요한 급성 열성 질환으로 조기 진단 및 치료에 보다 관심을 기울여야 할 것이다. Background : In Korea malaria has been rare, but since reemergence of indigenous vivax malaria in 1993, the number of cases of malaria have recently increased. We analyzed the cases of malaria who were treated in Kyung-Hee University College of Medicine with regard to define the clinical characteristics of malaria. Methods : We retrospectively analyzed of 32 cases of malaria admitted to Kyung-Hee University Hospital between 1991 and 1999. Malaria was diagnosed by peripheral blood smear. Results : Among a total of 32 cases, the number of yearly incidence of 1991, 1996. 1997, 1998 and 1999 were 1,1,3,13,14 respectively. It demonstrated the high incidence especially between July and August. The most patients (53.1%) resided in Yeonchon and Pajoo. Among them, 5 cases were female and 27 cases were male. The age distribution ranged from 22 to 76 year old. The high incidence of age was between 20's and 30's. Military solidiers and ex-soldiers are 17 cases(59.4 %). The most frequent symptom was fever and chills (100%). Splenomegaly and hepatomegaly were also observed in 81.3 %(26 of 32) and 9.4 %(3 of 32) respectively. The laboratory findings were WBC 5.317/㎕. Hb 12.5±2.1 g/dl. platelet 78,906±68,391.4/㎕. GOT/GPT 43.7±26.7/49.6±57.3 IU/L. LD 678.3±50.1 IU/L. total bilirubin 1.6±0.9mg/dl- The all cases were treated suscessfully with hydroxychloroquine and primaquine. There were no central nervous system complications and pulmonary edema. Conclusion : Malaria is one of the important acute febrile illness with the high incidence between July and August.

폐농양 및 복부농양을 일으킨 Eikenella corrodens 감염 2예 : Two Case Reports and Review

정용희,류미숙,김영식,이우인,이희주,서환조 대한화학요법학회 2000 대한화학요법학회지 Vol.18 No.1

Eikenella corrodens is a slowly growing, facultative anaerobic gram-negative bacillus. It is a normal inhabitant of the human upper respiratory tract, and it is recognized as an infrequent cause of invasive disease. To date, a few cases of E. corrodens infection were noted from all other organ. We report herein two cases of E. corrodens infection. In one case E. corrodens was isolated in the lung abscess and in the other case it was in the appendiceal abscess. The patients were treated empirically with penicillin G. The results of the bacterial culture and sensitivity test were available with it. The patients were discharged 15 days later with marked improvement after treatment. Our report clearly demonstrates that E. corrodens can be the pathogen of lung abscess and intraabdominal abscess. We reviewed descriptions from the literature of infections caused by E. corrodens.

Plyometric Training과 비타민 C 투여가 남고생의 체력, 혈중 젖산, 암모니아 및 젖산탈수소효소에 미치는 영향

장준원,김세종,이현미,서혜림,조현숙,고정림,염종우,예정복,백영호 釜山大學校 附設 體育科學硏究所 2003 體育科學硏究所 論文集 Vol.19 No.-

The purpose of this was to examine the effect of plyometric training and vitamin C ingestion on physical fitness and fatigue substance....

Methionine Analogue Probes Functionally Important Residues in Active Site of Methionyl-tRNA Synthetase

Jo, Yeong-Joon,Lee, Sang-Won,Jo, Myung-Kyun,Lee, Jee-Woo,Kang, Mee-Kyoung,Yoon, Jeong-Hyeok,Kim, Sung-Hoon Korean Society for Biochemistry and Molecular Biol 1999 Journal of biochemistry and molecular biology Vol.32 No.6

Aminoacyl-tRNA synthetases are essential enzymes catalyzing the attachment of specific amino acids to cognate tRNAs. In the present work, the substrate analogue L-methionine hydroxamate was used to identify functional residues located in the active site of the E. coli methionyl-tRNA synthetase (MetRS). This compound inhibited bacteria, yeast, and human MetRS activities to a similar degree, suggesting a conserved active site structure and mechanism between MetRSs of different phylogenetic domains. Mutants of the E. coli MetRS resistant to methionine hydroxamate were also isolated. These mutants contained a substitution either at T10, Y15, or Y94. These residues are highly conserved among the different MetRSs and the mutants showed decreased aminoacylation activity, suggesting their functional and structural significances. The putative roles of these residues are discussed on a structural basis.

Long-acting Recombinant Human Granulocyte Colony Stimulating Factor (rhG-CSF) with a Trimer-structured Polyethylene Glycol

( Yeong Woo Jo ),( Mee Yong Lee ),( Yun Kyu Choi ),( Sung Hee Lee ),( Soo Hyoung Kang ),( Kun Na ),( Yu Seok Youn ),( Eung Chil Choi ) 한국약제학회 2010 Journal of Pharmaceutical Investigation Vol.40 No.6

Mono PEGylated rhG-CSF (PEG-G-CSF) prepared by utilizing unique PEG was purified and characterized by cation-exchange chromatography. A unique, trimer-structured PEG was chosen for PEGylation of rhG-CSF among various PEG moieties. The in-vitro bioactivity, stability, and pharmacokinetics of mono-PEG-G-CSF were examined and compared to those of native rhG-CSF. Mono PEG-G-CSF exhibited reduced in-vitro bioactivity to native rhG-CSF but showed an excellent in-vivo bioactivity and stability. Furthermore, it showed markedly reduced clearance in rats, thereby increasing the biological half-life by about 4.5-fold compared to that of native rhG-CSF. The results suggest that this unique, trimerstructured 23 kDa PEG can provide advantages to improve the bioactivity of therapeutic proteins in clinical use.

Long-acting Recombinant Human Granulocyte Colony Stimulating Factor (rhG-CSF) with a Trimer-Structured Polyethylene Glycol

Jo, Yeong-Woo,Lee, Mee-Yong,Choi, Yun-Kyu,Lee, Sung-Hee,Kang, Soo-Hyoung,Na, Kun,Youn, Yu-Seok,Choi, Eung-Chil The Korean Society of Pharmaceutical Sciences and 2010 Journal of Pharmaceutical Investigation Vol.40 No.6

Mono PEGylated rhG-CSF (PEG-G-CSF) prepared by utilizing unique PEG was purified and characterized by cation-exchange chromatography. A unique, trimer-structured PEG was chosen for PEGylation of rhG-CSF among various PEG moieties. The in-vitro bioactivity, stability, and pharmacokinetics of mono-PEG-G-CSF were examined and compared to those of native rhG-CSF. Mono PEG-G-CSF exhibited reduced in-vitro bioactivity to native rhG-CSF but showed an excellent in-vivo bioactivity and stability. Furthermore, it showed markedly reduced clearance in rats, thereby increasing the biological half-life by about 4.5-fold compared to that of native rhG-CSF. The results suggest that this unique, trimer-structured 23 kDa PEG can provide advantages to improve the bioactivity of therapeutic proteins in clinical use.

사용자 활동에 기반한 자동 타임라인 생성 서비스

장우영(Woo-Yeong Jang),박채성(Chae-Seong Park),조남규(Nam-Gyu Jo),양현모(Hyeon-Mo Yang),안재혁(Jae-Hyeok An),오병우(Byoung-Woo Oh) 한국정보기술학회 2021 Proceedings of KIIT Conference Vol.2021 No.6

최근 스마트기기가 보편화하면서 점차 종이를 대체하고 있다. 자신의 일을 기록하고자 원하는 사람은 일기장에 작성하는 것이 아닌 일기 애플리케이션을 통해 하루의 일을 텍스트 형식으로 정리한다. 그러나 현재 대다수의 애플리케이션은 정확한 시간에 일어난 일을 한눈에 보기 어려우며 자신의 기억력에 의존해야만 하는단점이 존재하므로 노년층은 기록 시기를 놓칠 수 있다. 본 논문에서는 기억력에 의존적인 단점을 개선함과 동시에 기존의 일기 애플리케이션의 패러다임을 바꿀 수 있도록 사용자의 타임라인을 생성해주는 서비스를 제안한다. 타임라인은 시간별로 정리되므로 일어난 시각을 정확하게 알 수 있다. 사용자는 애플리케이션을 실행할 필요 없이 간편 답장 기능을 통해 하루의 일을 작성할 수 있게 되고, 애플리케이션은 사용자의 활동 기록을 바탕으로 타임라인을 자동으로 생성해주므로 직접 쓰는 것이 미숙한 사람에게 편의성을 제공한다. As smart devices are becoming more common in recent years, they are gradually replacing paper. Those who want to record their work organize their day"s work in text format through a diary application rather than writing it in a diary. However, most of the current applications are difficult to see at a glance what happened at the correct time, and there is a drawback of having to rely on one"s own memory, so older people may miss the recording period. In this paper, we propose a service that creates a user"s timeline to improve the memory-dependent shortcomings and change the paradigm of the existing diary application. The timeline is organized by time, so you can know exactly when it happened. The user can write the day"s work through the simple reply function without having to run the application, and the application automatically creates a timeline based on the user"s activity record, providing convenience for inexperienced people to write directly.

조선 초기 신분 제도의 사회적 위상과 관념적 구조

조우영(Jo Woo-yeong) 한국법사학회 2003 法史學硏究 Vol.28 No.-

[PA-0034] Transcriptome analysis by RNA-seq reveals genes related to flower coloration in Dendrobium mutants

Dong-Gun Kim(Dong-Gun Kim),Jaihyunk Ryu(Jaihyunk Ryu),Bawool Yang(Bawool Yang),Ye-Jin Lee(Ye-Jin Lee),Yeong Deuk Jo(Yeong Deuk Jo),Joon-Woo Ahn(Joon-Woo Ahn),Sang Hoon Kim(Sang Hoon Kim) 한국육종학회 2022 한국육종학회 공동학술발표집 Vol.2022 No.-