http://chineseinput.net/에서 pinyin(병음)방식으로 중국어를 변환할 수 있습니다.
변환된 중국어를 복사하여 사용하시면 됩니다.
Surface modified Ti based metallic glasses for bioactivation by electrochemical treatment technique
Oak, J.J.,Inoue, A.,Rao, K.V.,Chun, H.H.,Park, Y.H. Elsevier Sequoia 2014 Journal of Alloys and Compounds Vol.615 No.suppl1
The aim of this study is surface modification of Ni-free type Ti based metallic glass (Ti<SUB>42</SUB>Hf<SUB>11</SUB>Cu<SUB>11</SUB>Pd<SUB>36</SUB>at.%) for increasing calcification by electrochemical treatment. Ni-free type Ti based metallic glass has excellent mechanical and chemical properties which are comparable with those of Ti based alloys. Surface of Ti based metallic glasses was prepared as follows; one is anodically-oxidized porous layer by potentiostatic control in 5M NaOH solution at 25<SUP>o</SUP>C for 2h, and the other is simple hydrothermal treated poros layer by immersion in 5M NaOH solution at 60<SUP>o</SUP>C for 24h. The synthesized surface structures were characterized by X-ray diffraction (XRD) identification, SEM observation, energy dispersive X-ray spectroscopy (EDS) analysis and Auger electron spectroscopy (AES) analysis. These surfaces on the modified specimens have nano-mesh laminated structures and are consist of sodium titanate and titanium oxide. In addition, the above two types surfaces with nano-mesh laminated layer were immersed in Hank's balance salt solution (HBSS) at 37<SUP>o</SUP>C for 21days for evaluation of calcification. The apatite-forming ability on these surfaces is observed by SEM observation and EDS analysis. As stated above surface modifications are also discussed about calcification effect by different surface treatment and different formability of porosity in this study.
Characterization Of The Graded Microstructure In Powder Sintered Porous Titanium
Oak, J.-J.,Bang, J.I.,Bae, K.-C.,Kim, Y.H.,Lee, Y.-C.,Chun, H.H.,Park, Y.H. PAS 2015 ARCHIVES OF METALLURGY Vol.60 No.2
<B>Abstract</B><P>The proposed sintering process produce porosity and functional graded microstructure in the sinterd titanium powders. Titanium powders with different micro sizes were sintered at the proposed temperature region at 1200 and 1300°C for 2h. The apatite-forming on the graded microstructure is observed by immersion test in Hanks balanced salt soluion at 37°C. Sintering condition of titanium powders is estimated by thermogravitmetry-differential thermal analysis (TG-DTA). The synthersied surface structures and apatite-forming ability were characterized by a field emission scanning electron microscopy (FE-SEM) observation and energy dispersive X-ray spectroscopy (EDS) analysis. As results, these graded microstructure of sintered porous titanium powders reveals apatite-forming ability as osseointegration by calcification in Hanks balanced salt soluion(HBSS) at 37°C.</P>
박상균,이병철,이춘희,김문중,장봉열,한기옥,허기석 대한내과학회 1990 대한내과학회지 Vol.39 No.1
Thrombocytopenia with decreased megakaryocytes is a rare disorder characterized by thrombocytopenia due to a total absence or a marked reduction in the number of bone marrow megkaryocytes. We experienced a case of thrombocytopenia with decreased megakaryocytes in a 15-year-old girl, who was admitted with chief complaints of epistaxis and purpura on the lower extremities. There was a marked decrease of megakaryocytes in the marrow, and only minimal changes in other hematopoietic cell lines were seen. Follow-up studies, including bone marrow aspiration and biopsy which were performed eight months later, revealed typical features of aplastic anemia.
Angiogenic Squamous Dysplasia as a Biomarker to Predict Progression to Lung Cancer
( Chul Ho Oak ),( Tae Won Jang ),( Maan Hong Jung ),( Bong Kwon Chun ),( Soon Kew Park ) 한국조직공학·재생의학회 2009 조직공학과 재생의학 Vol.6 No.4
Angiogenic squamous dysplasia(ASD) is a term that has been introduced to describe a neoangiogenesis seen in bronchial dysplasias. One of many important angiogenic cytokines are the VEGFs. The VEGFs and their receptors are prime regulators of both physiological and pathological angiogenesis. But it is not clear whether ASD demonstrates the angiogenic switch or not, what is the mechanism of ASD. In this study, Immunohistochemical studies showed an expression of vascular endothelial growth factor in dysplastic bronchial epithelium. VEGF in the dysplastic cells in preneoplastic epithelium was observed in twenty-nine of 31 patients with ASD(93.5%), indicating that angiogenic switch occurred in early preneoplastic lesion including hyperplasia, metaplasia. ASD lesions were not identified in patients with COPD, whereas in 31 of 90 (34.4%) patients with squamous carcinoma, ASD was evident. In addition, the incidence of ASD increased as the hisological grade of preneoplastic lesion advanced, suggesting that the ASD may be a direct precursor lesion(P = 0.03). The author followed up the biologic behavior of dysplasia with respect to the status of ASD. There were significant associations between histological outcome and ASD status during the follow-up period(P = 0.04). These results suggested that ASD be used as biomarkers to predict which dysplasias will progress to squamous cell carcinoma. Macrophages were identified in all(100%) tumor stroma and ASDs. The number of macrophage beneath ASD was significantly higher than that beneath other abnormal epithelium. In addition, the number of macrophages beneath ASD was significantly correlated with the count of microvessels beneath ASD. The results of the present study suggested that Angiogenic squamous dyplasia(ASD) may represent an precursor of lung cancer and may serve as an useful intermediate pathologic biomarker for early detection of lung cancer and chemoprevention. Macrophage beneath ASD may play an important role in early angiogenesis of ASD.
천경희,박영순,옥지원,Chun, Kyunghee,Park, Young Soon,Oak, Ji Won 연세대학교 의과대학 2021 의학교육논단 Vol.23 No.1
In light of the need for a tool to evaluate the clinical practice education environment as perceived by medical and nursing students, this study is was conducted to develop and validate the Korean version of the Undergraduate Clinical Education Environment Measure (K-UCEEM) as a measurement tool for managing the clinical practice education climate and quality of education. For validation, the UCEEM consisting of 25 items developed by Pia Strand in 2013 was adapted according to standard translation procedures. The K-UCEEM questionnaire was administered to 73 medical students and 135 nursing students who participated in clinical practice at one medical institution. Exploratory factor analysis and confirmatory factor analysis were conducted to confirm the validity of the instrument's structure. In order to determine referential validity, the relationships among stresses in clinical practice were examined, and differences in factor scores were compared by gender and college. It was confirmed that the scale of 24 items and five factors showed a moderate model fitness index. The reliability of the factors ranged from 0.786 to 0.867. In addition, all five factors were found to have negative correlations with the clinical practice stress sub-factor, and there were statistically significant differences by gender and college. Through this study, the validity and reliability of the K-UCEEM were verified. In the future, it is expected that further verification of the scale, as well as evaluation and improvement of the clinical practice education environment based on this scale, will occur.
통영 지역의 암반 조간대에서 배출수 유입으로 인한 해조 군집 구조와 엽체 내 질소 함량의 변화
강윤희 ( Yun Hee Kang ),박상률 ( Sang Rul Park ),옥정현 ( Jung Hyun Oak ),이진애 ( Jin Ae Lee ),정익교 ( Ik Kyo Chun ) 한국수산학회 2009 한국수산과학회지 Vol.42 No.3
Enrichment in nutrients coming from urban sewage outfalls can lead to eutrophication in coastal areas, which can also change the species composition and community structure of macroalgal communities. We investigated the structure of the macroalgal community within three rocky shores in order to assess any possible differences in their characteristics. Site 1 was located near Tongyeong city`s sewage outfall, Site 2 was located near a public beach area, and Site 3 faced open channel of the Ocean. All three sites were located within the same stretch of the coast, where Site 2 was located between sites 1 and 3. We measured the nutrient concentration in water and the tissue nitrogen content in macroalgae samples. Nutrients in the water column surrounding site 1 were high in ammonium (30.2±1.8μM), nitrate (26.2±0.1μM), and phosphate (2.7±0.1μM) content, and were characterized by low numbers of macroalgal species and species and a low species diversity index. In contrast, site 3 exhibited relatively low nutrient concentration levels and a high number of macroalgal species and a high species diversity index. Comparative analysis showed that the tissue nitrogen content of macroalgae were significantly (P<0.05) affected by the nutrient concentration in the water column. The tissue nitrogen content of green algae within site 1 was higher than the others sites. However, the tissue nitrogen content of brown algae was similar at all three sites. Thus, the tissue nitrogen content of macroalgae and the macroalgal community structure of intertidal rocky shores were dependent on location and the performance of macroalgal communities was dependent on water quality.