Coating with boron nitride on SiC fiber using atomic substitution

Woo‑Seong Tak,Jin‑Uk Hwang,Young‑Keun Jeong,Woo‑Sik Kim 한국세라믹학회 2020 한국세라믹학회지 Vol.57 No.2

To increase the mechanical properties of ceramic matrix composite, it is important that formation of lubricant layer for crack deflection between matrix and fiber. Therefore, we fabricated uniform boron nitride (BN) lubricant layer using atomic substitution method. Silicon carbide (SiC) fiber surface was modified with amine groups using (3-amonipropyl)triethoxysilane to coat SiC fiber with BN as a solid lubricant. Then, surface was coated with graphene oxide (GO). Boric acid powder was supplied to the GO-coated fibers and the samples were heat-treated at 1200–1400 ℃ under N2 and NH3 atmospheres. An uniform BN layer could be coated on SiC fiber with 10 nm-1.11 μm. Crystallinity and thickness of BN layer could be controlled by reaction temperature. It was also confirmed that crystalline BN formed under process conditions of higher than 1400 ℃.

The HBV DNA Amounts in Serum Have No relationship with ALT level and Hetergeneous Population Coexits in Chronic Hepatitis B Virus Infection

Chun, Yoon-Keun,Ha, Joo-hun,Hong-Jung-Woo,Oh, Soo-Myung,Kim, Sung-Soo 경희대학교 동서의학연구소 1999 INTERNATIONAL SYMPOSIUM ON EAST-WEST MEDICINE Vol.1999 No.1

Yoon-Keun Chun¹,Joohun Ha□Hong-Jung Woo□, Soo Myung Oh□,Sung Soo Kim□ ¹Department of Molecular Biology, College of Medicine,²Department of Surgery, college of Medicine,³Department of Internal Medicine, College of Oriental Medicine,and ⁴East-Weat Medical Reserch Institute,Kyung Hee University, Seoul, Korea. The HBV DNA Amounts in Serum Have No relationship with ALT level and Hetergeneous Population Coexits in Chronic Hepatitis B Virus Infection. Proceedings of International Symposium on East-West Medicine, Seoul. 212-230, 1999. -Hepatitis B is caused by hepadnavirus. Hepatitis B virus replicates through 3.5kb pregenomic RNA intermediate which is regulated by core promoter. Pathogenesis of hepatitis B virus has been bilieved the result of host immune response. But recently many studies have reported that high level of viral replication caused by mutation in core promoter might result in severs hepatitis. But these studies were performed in vitro, not in vivo. So there is yet debate about which factor, viral of host factor, is more important in pathogenesis of hepatitis B virus. So we measured real viral replication level in 204 chronic hepatitis B patients by quantifying HBV DNA from sera by our novel PCR-based more sensitive method, and compared these results with ALT level measured from same sera, which indicates liver cell damage. Surprisingly there are no significant correlation between HBV DNA quantity and ALT level. Then we cloned core promoter region. In SSCP, we found that many viral mutants coexist in one patient. Base on SSCP result, we chose main viral core promoter type in each patients, which is thought to determine overall viral replication level in this patient. Main type of core promoter region of each 41 patients were directly sequenced. And with these we measured promoter activity by luciferase assay system and compared promoter activity with on another. We found tha there were some differences in promoter activity according to core promoter sequences. And we constructed replication-competent viral constructs with core promoter from 41 patients and Transfected these into HepG2 cell and measured HBV DNA by southern blot. There were also differences in HBV DNA quantity according to core promoter sequences. On these all results we investigated correlation between the effect of HBV core promoter on viral replication in vitro and HBN DNA quantity, ALT level from sera of each patients. We found there is no significant correlation among them. As a result, we concluded that in determining severity chronic hepatitis B patients, host factors of each patient is more important rather than replicative activity of virus itself.

Identification of Genes Modulated by High Extracellular Calcium in Coculture of Mouse Osteoblasts and Bone Marrow Cells by Oligo Chip Assay

Kim, Hyung-Keun,Song, Mina,Jun, ji-Hae,Woo, Kyung-Mi,Kim, Gwan-Shik,Baek, Jeong-Hwa The Korean Academy of Oral Biology 2006 International Journal of Oral Biology Vol.31 No.2

Calcium concentration in the bone resorption lacunae is high and is in the mM concentration range. Both osteoblast and osteoclast have calcium sensing receptor in the cell surface, suggesting the regulatory role of high extracellular calcium in bone merabolism. In vitro, high extracellular calcium stimulated osteoclastogenesis in coculture of mouse osteoblasts and bone marrow cells. Therefore we examined the genes that were commonly regulated by both high extracellular calcium and 1,25(OH)_(2)vitaminD_(3)(VD3) by using mouse oligo 11 K gene chip. In the presence of 10 mM[Ca^(2+)]e or 10 nM VD3, mouse calvarial osteoblasts and bone marrow cells were co-cultured for 4 days when tartrate resistant acid phosphatase-positive multinucleated cells start to appear. Of 11,000 genes examined, the genes commonly regulated both by high extracellular calcium and by VD3 were as follows; 1) the expressions of genes which were osteoclast differentiation markers or were associated with osteoclastogenesis were up-regulated both by high extracellular calcium and by VD3; trap, mmp9, car2, ctsk, ckb, atp6b2, tm7sf4, rab7, 2) several chemokine and chemokine receptor genes such as sdf1, scya2, scyb5, scya6, scya8, scya9, and ccr1 were up-regulated both by high ectracellular calcium and by VD3, 3) the genes such as mmp1b, mmp3 and c3 which possibly stimulate bone resorption by osteoclast, were commonly up-regulated, 4) the gene such as c1q and msr2 which were related with macrophage function, were commonly down-regulated, 5) the genes which possibly stimulate osteoblast differentiation and/or mineralization of extracellular matrix, were commonly down-regulated;slc8a1, admr, plod2, lox, fosb, 6) the genes which possibly suppress osteoblast differentiation and/or mineralization of extracellular matrix, were commonly up-regulated;s100a4, npr3, mme, 7) the genes such as calponin 1 and tgfbi which possibly suppress osteoblast differentiation and/or mineralization of extracellular matrix, were up-regulated by high extracelluar calcium but were down-regulated by VD3. These results suggest that in coculture condition, both high extracellular calcium and VD3 commonly induce osteoclastogenesis but suppress osteoblast differentiation/mineralization by regulating the expression of related genes.

6-hydmxydopamine 파킨슨병 모델에서 Apomorphine의 투여에 따른 회전운동 변화의 시간적 추이

홍근식,김병곤,전범석,윤병우,이광우,노재규,이상복,명호진 대한신경과학회 1999 대한신경과학회지 Vol.17 No.1

간의 배아성 육종 -부분적으로 연골육종성 분화를 보인 1예 보고-

정우회,임현이,김호근,박찬일,오기근,최승훈 대한병리학회 1992 Journal of Pathology and Translational Medicine Vol.26 No.5

인체 Calbindin-D9k 항체 제작과 종특이적 활성

이근우, 홍의주, 이근식, Vu-Hoang Dang, 정의배 충북대학교 동물의학연구소 2006 Journal of Biomedical and Translational Research Vol.7 No.2

본문참고

비산재 중에 함유된 중금속의 용출특성에 관한 연구(1)

이우근,김진범,김은미 江原大學校 附設 環境硏究所 1997 環境硏究 Vol.14 No.-

The secondary environmental contamination is now feared by the land-fill treatment os fly ash from MSWI. It is urgently necessary to study the development of a proper technology for fly ash. considering the governmental plan for enhancing the rate of incineration. The leaching characteristics of MSWI ash were analyzed for pH, L/S ratio and leaching time in our study. According to the result, pH was decreased as the leaching time elapsed. The amounts of leached heavy metal were affected by L/S ratio. pH is the most important among the factors for affecting the amounts. Therefore, the leaching experiment must be excuted under the pseudo-actual condition(actual pH at the land-fill site)evaluating the risk.

지문과 정신분열증

우숙희,정국동,최송표,조근자,양은진,김수일,박경란,이영호,김원식 충남대학교 의과대학 지역사회의학연구소 1998 충남의대잡지 Vol.25 No.1

Fingerprint patterns of 333 schizophreniacs who met with the diagnostic criterias of International Pilot Study of Schizophrenia except items associated with chronicity in exclusion criteria were studied, and the following results were obtained. 1. The frequency distribution of the fingerprint patterns in the 333 schizophreniacs was ulnar loop, whorl, twinned loop, arch, radial loop in order in both control and schizophrenia groups. 2. Finger ridge counts of both sexes were decreased significantly in schizophrenia group. 3. Dissociation of fingerprint pattern in the schizophrenia group was 51.1%, which was far greater than 6.25% of control group. Number of dissociation was greatest in the thumb, followed by index, middle, ring, and little finger in order. According to the above results, it is considered that both the number of finger ridges and degree of dissociation of fingerprint patterns were closely related with schizophrenia. Analysis of fingerprints and palmprints with the aid of chromosomal analysis would contribute the early diagnosis and prevention of schizophrenia.

군무이탈 예측요인 분석에 관한 연구

정우근,이창무 한남대학교 사회과학연구소 2008 사회과학연구 Vol.17 No.-

Recently there have been concerns about human rights in military camp and young soldiers' maladjustment to military duty. Young soldiers' maladjustment and desertion from the military service would cause not only personal disaster but also serious military results such as a loss of military power, a weakening of morale in camp, and the decline of military dignity. In spite of the continuous efforts to prevent young soldiers' desertion from military service, the desertion has been continuously increasing. In this respect, this study approached differently from typical analysis about violence, brutality, and maladjustive behaviors during military service, and employed a three-dimensional methodology to find predictive factors including their childhood environment and social background and so on. 인권에 대한 관심이 커지면서 최근에는 군대 내 인권의 중요성이 강조되고 있다. 아울러 자유분방한 신세대 장병들의 군복무 부적응이 사회적 관심사가 되고 있다. 개인적인 성향이 강한 병사들이 군복무에 적응하지 못하고 고민하다가 군무이탈을 하게 되면, 이는 개인의 문제로 끝나는 것이 아니고 군 전투력 손실, 장병 사기 저하, 군 이미지 실추 등의 심각한 결과를 초래한다. 그 동안의 지속적인 군무이탈 예방 노력에도 불구하고 군무이탈은 꾸준히 발생하고 있다. 따라서 본 연구에서는 구타, 가혹행위, 복무부적응 등 기존의 단편적인 군무이탈 분석과 접근방법을 달리하여 군무이탈자의 성장환경 등 군 입대 전 가정ㆍ사회환경적 특징을 포함한 입체적인 분석을 통해 군무이탈 예측요인을 분석해 보고자 한다.

Flowable Resin을 이용한 접착식 보정장치의 결합강도 연구

강대근,손우성,김형일 大韓齒科器材學會 2004 대한치과재료학회지 Vol.31 No.4

This in vitro investigation was conducted to determine the bond strength of two resin material using universal testing machine and to verify the failure mode for each test specimen with stereoscope. Eighty human permanent maxillary and mandibular premolars were randomly divided into 2 groups (40 in each group). Teeth were mounted in stone block (2 teeth in each block) and a 3 mm diameter area of enamel of each sample were etched, rinsed, dried, and adhesives were applied according to the manufacturers' instructions. A bonded orthodontic retainer with triflex wire was bonded to buccal enamel surface. Debonding was then performed with a force using an Instron universal testing machine. The force was recorded at bond failure. The results data was collected and the mode of fracture failure recorded. The broken specimens were examined with 20× stereoscope to determine the fracture location or failure mode. Failures for each adhesive system were evaluated with ARI scores. The t-test was performed to determine any statistically significant differences among bond strength values of the two materials. And Chi-square test was used to compare the Modified adhesive remnant index (ARI) scores for the two groups. This in vitro study concluded that; 1. There was no statistical difference in mean bond strength between the flowable (Filtek Flow^(�)) and conventional (Filtek Z250^(�)) resin material (p=0.128). 2. The fracture modes of all samples were resin-wire interface failure or combination of enamel-resin and resin-wire interface failure. Bonded lingual retainer with flowable resin might have clinically acceptable bond strengths. Modes of failure site of flowable resin and conventional composite resin were similar.