통계적 유한요소모델을 이용한 발포금속의 기계적 특성

전성식 公州大學校 工學硏究院 生産技術硏究所 2003 論文集 Vol.11 No.-

In this paper, a modified and representative unit cell model was employed to study the mechanical behaviour of closed-cell metallic foams with varying spatial density distribution as well as material imperfections. The density variation was assumed to follow a statistical probability distribution of the Gaussian type. A multiple cell finite element model, utilising the modified unit cell, was developed. The model exhibits deformation patterns similar to those observed in testing. The nominal stress-strain curves obtained from quasistatic compressive as well as tensile of the foam were compared with experimental findings and were found to be in good agreement only if the appropriate density distribution and volume fraction of internal imperfections are taken into account. Moreover, maximum tensile strength of the aluminium foam was found to be more sensitive to the volume fraction of imperfection than standard deviation of the density

Ethyoene Oxide 폭로 근로자의 말초 임파구 자매염색분체 교환에 관한 연구

황천현,박종태,장성훈,김대성,이원진,김청식,김영환 大韓産業醫學會 1998 대한직업환경의학회지 Vol.10 No.4

Operators of hospital sterilizers who use ethylene oxide(EtO) were studied to determine the exposure of EtO level and the frequency of sister chromatid exchanges(SCEs) from June 12 to July 20, 1997. To evaluate SCEs in the peripheral blood cells, we selected 22 workers at the central supply room of 4 university hospitals and 22 unexposed workers at the same hospitals according to match sex, age, and smoking habit and also did questionnaires. The mean air concentrations(8-hr TWA) of EtO at 4 university hospitals were less than 1 ppm. The SCE frequencies in exposed workers to EtO and controls were normally distributed. The SCE frequencies in exposed workers to EtO and controls were 6.42±0.63, 5.86±0.69, respectively and their differences were statistically significant(p=0.0093). But there were no statistically significant differences in smoking, alcohol intake, coffee drinking. Especially smokers who exposed to EtO were increased SCE statistically significant than the exposed group who did not smoke.

免疫細胞 및 腫瘍細胞에 미치는 丹蔘의 效果

鄭鉉雨,姜聲度,陳千植 대한동의병리학회 1998 동의생리병리학회지 Vol.12 No.2

免疫은 人體內에서 어떤 요인으로 인해서든지 異物이 침입하거나 變異細胞가 발생하면 Immune system이 관여하여 異物은 물론 새로이 발생된 變異細胞를 非自己로 인식하여 처리하는 能力을 발휘함으로써 個體의 恒常性을 維持하려는 현상을 말하고, 이러한 免疫作用에 관여하는 細胞는 特異性 免疫에 관여하는 免疫細胞外에도 Macrophage, NK cell, 수지상세포 및 랑게르한스 세포등을 들 수 있으며, 腫瘍은 組織이 自律的으로 過剩 成長한 것으로 이것은 개체에 대해서 意義가 없거나 이롭지 않을뿐더러 正常組織에 대해서 破壞的인 작용을 하는 것으로 東醫學에서는 正氣補養 및 補血을 爲主로하면서 破積·活血·解鬱·行氣등의 治法들을 兼用하고 있고, 西醫學에서는 手術療法, 放射線療法, 化學療法 및 免疫療法과 遺傳子療法등을 使用하나 癌腫에 따른 感受性과 治療 後의 經過 그리고 副作用이 각기 다르고, 또 이에 따른 많은 문제점들을 안고 있는 것이다. 癌細胞의 增殖을 抑制하는 方法에는 necrosis와 apoptosis가 있는데, apoptosis란 necrosis(세포괴사)와는 대조되는 용어로 초기에 핵의 응축, 세포질의 응축, 수포상의 세포돌기 형성등이 관찰되고, 生體內의 apoptosis는 腫瘍發生時 macrophage에서 분비되는 각종 cytokine에 의해 일어나거나 cytotoxic T-lymphocyte에 의해 일어나는 것으로 抗癌劑들의 부작용 및 tumor regression과 관계가 있는 것으로 알려져 있다. Nitric oxide(NO)는 cNOS와 iNOS 2 종류가 있으며 cNOS는 vascular endothelium 및 brain에서, iNOS는 활성화된 macrophage 및 여러 세포에서 발견되었다. Macrophage가 생산하는 NO는 生體內에서 癌細胞를 공격하여 傷害시키는 癌 免疫의 effector로서 그 역할을 하고 있고, 癌細胞의 增殖을 抑制한다. 丹蔘은 活血祛瘀시키면서 凉血安神시기 때문에 産後瘀滯腹痛·경폐징하·心腹刺痛과 熱毒으로 인한 癰腫·瘡瘍등에 利用되고, 最近에는 肝臟腫大와 動脈硬化症, 그리고 食道癌·胸腺癌 및 腹腔腫瘍에도 사용하고 있는 藥物로 本 硏究에서는 丹蔘에 대한 癌細胞 增殖 抑制作用과 免疫細胞 增强作用을 관찰한 결과 丹蔘은 In vitro上에서 A431 cell line과 KHOS-NP cell line의 增殖을 抑制하지는 않았지만 마우스 胸腺 및 脾臟細胞의 增殖을 活性化시켰다. 그러나 腹腔 macrophage에서 생성되는 NO는 丹蔘에 의해 in vitro상에서 억제되었고 in vivo상에서도 對照群과 큰 차이를 보이지 않았는데, 이는 丹蔘이 腹腔 macrophage의 活性化보다는 T-lymphocytes나 splenocytes의 增殖에 작용하는 것으로 思料된다. To investigate effect of water extract of Salviae Radix on human cancer cell-lines and immunocytes, this research estimated the proliferation of A431 cell lines, KHOS-NP cell lines, mouse thymocytes and mouse splenocytes, nitric oxide(NO) production from peritoneal macrophages, apoptosis and sub-population of mouse thymocytes. The result were obtained as follows ; 1. Salviae Radix wasn't effect the proliferation of A431 cell lines and KHOS-NP cell lines. 2. Salviae Radix was accelerate the proliferation of mouse thymocytes and splenocytes. 3. Salviae Radix was not accelerate the NO production from peritoneal macrophages in vitro. 4. Salviae Radix was inhibited the NO production from peritoneal macrophages in vivo. 5. Salviae Radix was accelerate the induction of apoptosis and sub-population of the mouse thymocytes.

내시경으로 확인된 상부소화관 용종의 임상적 고찰

김영건,김병호,성자원,이기천,허승식,이종선,정현용,이헌영 충남대학교 의과대학 지역사회의학연구소 1991 충남의대잡지 Vol.18 No.2

From January 1987 to October 1991, we performed 14,333 cases of upper gastrointestinal endoscopy and diagnosed 527 cases with U.G.I polyp. We assesed these 527 cases and obtained following results: 1) The overall incidence of U.G.I. polyps was 3.6%, and there was no sexual difference. The peak incidence was in 6th decades(32.4%). 2) The U.G.I. polyps were located chiefly at stomach(415 cases, 78.7%), among which antrum occupied antrum 43.5%, body 24.0% and funds 5.1%. And the others were esophagus(6.5%) and duodenum(12.3%). 3) The size of U.G.I. polyp was below 1cm in 72.3%, from 1cm to 1.9cm in 20.7% and above 2cm in 7.0%. According to Yamada' classification, type Ⅰ, Ⅱ, Ⅲ and Ⅳ was 31.9%, 51.3%, 13.7% and 3.0%. 4) Histological nature of U.I.G. polyp were hyperplastic polyp(85.8%), adenomatous polyps(9.3%), carcinomatous polyps(3.3%) and etc. The size of neoplastic polyp such as adenomatous polyps(mean 1.0±0.7cm) and carcinomatous polyps(niean 2.0±1.8) were larger man hyperplastic polyp(mean 0.6±0.4) (p<0.05) 5) The gastric polyps were associated with peptic ulcer(7.5%), gastric cancer(3.2%), other malignancy(3.5%), hepatobiliary disease(5.5%), post subtotal gastrectomy(5.5%). And others(75%) werenot associated with specific disease.

자가 산부식 프라이머의 세포독성에 관한 실험적 연구

이창훈,김인령,김규천,김성식,순우성 대한치과교정학회 2006 대한치과교정학회지 Vol.36 No.6

자가 산부식 프라이머는 세포독성이 있는 것으로 알려져 있어 교정치료를 하는 동안 치주조직에 손상을 일으킬 수 있다. 본 연구의 목적은 자가 산부식 프라이머가 치주조직에 미치는 영향을 평가해 보고 이를 전통적인 접착법에 사용되는 프라이머와 비교하기 위하여 시행되었다. 시편은 임상에서 브라켓 접착 시 사용하는 Transbond XT Adhesive (3M Unitek, Monrovia, CA, USA)를 각각 Transbond XT Primer (3M Unitek, Monrovia, CA, USA), Clearfil SE bond (Kuraray, Osaka, Japan), Transbond Plus Self Etching Primer, Adper Prompt L-Pop (3M Unitek, Monrovia, CA, USA)과 혼합한 후 광중합하여 제작하였고, Transbond XT Adhesive를 중합한 대조군과 비교하였다. 이를 배양된 HGF-1 (Human Gingiva Fibroblast), HaCaT (Human Keratinocyte cell line), RHEK (immortalized Human Epidermal Keratinocyte)에 노출시킨 후 세포의 형태 변화를 관찰하였고, MTT assay를 시행하여 세포독성을 비교, 평가하였다. 실험결과 72시간 후 HGF-1, HaCaT, RHEK를 이용한 실험에서 모든 프라이머의 세포독성이 높게 나타나 세포 돌기의 위축, 세포 형태의 변화, 세포 수의 감소, 세포의 괴사가 관찰되었다. MTT assay실험 시 HGF-1을 이용한 실험에서 Clearfil SE Bond, Transbond XT Primer, Transbond Plus SEP, Adper Prompt L-Pop의 순으로 세포독성이 높게 나타났고, HaCaT를 이용한 실험에서 Clearfil SE Bond, Adper Prompt L-Pop, Transbond Plus SEP, Transbond XT Primer의 순으로 세포독성이 높게 나타났으며, RHEK를 이용한 실험에서 Clearfil SE Bond, Transbond XT Primer, Adper Prompt L-Pop, Transbond Plus SEP 순으로 세포독성이 높게 나타났다. 자가 산부식 프라이머는 전통적으로 사용되는 프라이머와 마찬가지로 세포독성이 유의하게 높으므로 구강내 사용시 주의가 필요하다. Objective: Several ions and components are released from self-etching primers in the oral cavity. This may cause injury to the periodontal tissues throughout orthodontic treatment. The purpose of this study was to assess the cytotoxicity of self-etching primers to HGF-1 , HaCaT, and RHEK cells. Method: Transbond XT Primer (3M Unitek, Monrovia, CA, USA), and self-etching primers, Clearfil SE Bond (Kuraray, Osaka, Japan), Transbond Plus SEP (3M Unitek, Monrovia, CA, USA), and Adper Prompt L-Pop (3M Unitek, Monrovia, CA, USA), were evaluated by MTT assay, and cellular changes were also observed, Results: In all cells after 72 hours with all primers, severe morphological changes such as atrophy and necrosis were observed. In the MTT assay using HGF-1, Clearfil SE Bond, Transbond XT Primer, Transbond Plus SEP, and Adper Prompt L-Pop were lined up in order of ascending cytotoxicity. When using HaCaT, Clearfil SE Bond, Adper Prompt L-Pop, Transbond Plus SEP, and Transbond XT Primer were lined up in order of ascending cytotoxicity. When using RHEK, Clearfil SE Bond, Transbond XT Primer, Adper Prompt L-Pop, and Transbond Plus SEP were lined up in order of ascending cytotoxicity Conclusion: The result of this study shows that care is needed because self-etching primers show cytotoxic properties similar to conventional primers.

내시경으로 진단된 소화성 궤양의 임상적 고찰

김영건,육은주,김성걸,임의혁,성자원,김병호,허승식,이기천,정현용,이헌영 충남대학교 의과대학 지역사회의학연구소 1993 충남의대잡지 Vol.20 No.2

A clinical analysis was performed of 3055 pateints with peptic ulcer who were diagnosed with gastroduodenoscopy, in Hospital of Chungnam National University College of Medicine from July 1988 to May 1993. 1) During the period 1988-1993, The proportion of gastric ulcer among peptic ulcer decreased from 47.8% to 42.8%, but that of duodenal ulcer increased from 36.8% to 39.6%. 2) Of the 3055 cases, the number of patients with esophageal ulcer was 98(3.2%), with gastric ulcer 1407(41.6%), with. duodenal ulcer 1104(36.1%), with channel ulcer 149(4.9%), and with combind ulcer 297(9.7%). 3) We observed a peak incidence of peptic ulcer in the 50-69age group, gastric ulcer in the 5069age, duodenal ulcer in the 40-59age group. The ratio of male to female was 3.6 : 1 in peptic ulcer, 4.4 : 1 in gastric ulcer, 3.0 : 1 in duodenal ulcer. 4) The common site was angle in gastric ulcer, and bulb in duodenal ulcer. 5) The active stage was 39.4% of gastric ulcer, and 37.4% of duodenal ulcer, the healing stage was 34.2% of gastric ulcer, and 17.9% of duodenal ulcer, and the scar stage of gastric ulcer was 26.4%, and duodenal ulcer was 44.7%. 6) The size of ulcer was less than 1Cm in 66.7% of gastric ulcer, and in 75.5% of duodenal ulcer, the size of ulcer was greater than 2Cm in 13.2% of gastric ulcer, and in 6.5% of duodenal ulcer. 7) The frequency of multiple ulcer was 29.9% in gastric ulcer, and 16.5% in duodenal ulcer.

통계적 유한요소모델을 이용한 발포된 금속기지 복합재료의 인장특성

전성식 ( Seong Sik Cheon ) 한국복합재료학회 2004 Composites research Vol.17 No.2

본 연구에서는 폐쇄형 발포금속의 인장 특성을 이해하기 위하여 수정된 단위모델을 제시하였다. 또한 발포금속의 밀도는 가우스 분포에 의거하여 확률적으로 분포한다고 가정하고 본 연구에서 제시된 수정 단위 모델을 조합하여 유한요소 모델을 제안하였다. 이 모델은 실제 인장 시험과 유사한 변형거동을 보이는 것을 확인하였고, 적절한 밀도 분포와 내부 기공을 고려하게 되면, 해석에서 구해진 최대 인장 강도가 근사적으로 실험결과와 일치하는 것을 볼 수 있었다. 또한, 발포 알루미늄의 최대 인장 강도는 밀도 분포의 표준편차보다는 내부 기공 부피분율에 더 민감하게 변하는 것으로 밝혀졌다. In this paper, a modified and representative unit cell model was employed to study the tensile behaviour of closed-cell metallic foams with varying spatial density distribution as well as material imperfections. The density variation was assumed to follow a statistical probability distribution of the Gaussian type. A multiple cell finite element model, utilising the modified unit cell, was developed. The model exhibits deformation patterns similar to those observed in tensile testing. The nominal stress-strain curve obtained from quasistatic tensile of the foam was compared with experimental findings and was found to be in good agreement in the scheme of maximum strength only if the appropriate density distribution and volume fraction of internal imperfections are taken into account. Moreover, maximum tensile strength of the aluminium foam was found to be more sensitive to the volume fraction of imperfection than standard deviation of the density.

Expression Levels of Plasma Angiogenic Factors during Early Pregnancy in Hanwoo

Bae, Seong-Hun,Yang, Byoung-Chul,Joo, Seok-Cheon,Min, Kwan-Sik,Yoon, Jong-Taek,Jin, Dong-Il,Kim, Tae-Hun,Seong, Hwan-Hoo,Hwang, Seong-Soo The Korean Society of Animal Reproduction 2008 Reproductive & developmental biology Vol.32 No.4

This study was conducted to compare the expression pattern of the specific factors associated with pregnancy and angiogenesis during early pregnancy in Hanwoo. Synchronized female Hanwoo ($4{\sim}6$ year-old) were inseminated artificially. After 10 weeks after artificial insemination (AI), the pregnancy was tested by rectal palpation method. Three pregnant and non-pregnant Hanwoo were used in this experiment, respectively. The plasma progesterone level was measured by ELISA. Western blot analysis was performed to detect the expression of pregnancy associated glycoprotein (PAG) or angiogenic factors (VEGF, B-FGF, ANP-1, and TIE-2). The plasma P4 level was increase gradually in pregnant group and maintained high level. The concentration of PAG was significantly higher from $5^{th}$ weeks in pregnant group compared to that of non-pregnant group (p<0.05). The concentrations of the VEGF (p<0.05), B-FGF (p<0.05), and ANP-1 (p<0.05) were significantly increased from $6^{th}\;or\;7^{th}$ week after AI in pregnant group, respectively. And the intensity of TIE-2, ANP-1 receptor, was well matched with ANP-1 (p<0.05). Taken together, it can be postulated that the blood vessels connected with fetus and dam were formed dramatically around 40 days after AI, because the expression levels of the angiogenic factors were increased significantly from this time in pregnant Hanwoo.

상부위장관출혈의 임상적고찰

이천식(Cheon Sik Lee),서원영(Won Young Seo),오성웅(Seong Ung Oh),이재준(Jae Jun Lee),김종인(Jong In Kim),이성주(Seong Joo Lee) 대한내과학회 1988 대한내과학회지 Vol.35 No.3

N/A One hundred and sixty five cases of uper gastrointestinal bleeding were examined by fiberoptic endoscopy at Busan Medical Center from July 19S4 to June 1987. The results obtained were as follows; 1) The sex incidence of upper gastrointestinal bleeding revealed a greater prevalence in males than in females with a ratio of 4 to 1 and the peak age group were in the 5th and 6th decades. 2) The causative disease which were found to protace upper gastrointestinal bleeding were in the order of frequency of peptic ulcer (43.0%), esophageal varices (21.8%), hemorrhagic gastritis(18.8%), stomach cancer (9.1%), Mallory-Weiss syndrome (3,6%) and marginal ulcer. The incidence of upper gastrointestinal bleeding of unknown origin was 3.1%. 3) On of cyamination the mode of upper gastrointestinal bleeding, the incidence of melenal only was noted in 36.4% of the cases, hemestasis only in 32.7% and hematemesis with melena in 30.9%. 4) The severity of upper gastrointestinal bleeding was classified by cammock's criteria as massive in 46.1%, moderate in 40.0% and mild in 13.9% of the cases. 5) The frequency of upper gastrointestinal bleeding at admission was first time bleeding in 41.8% of the cases, second time bleeding in 20.0% third time bleeding in 17.0% and over third time bleeding in 21.2%. 6) The success rate in identifying the bleeding site in relation to the time of endoscopy after upper gastrointestinal bleeding began was 69.4% within 24 hours, 54.3% in 24-48 hours, 17.9% In 48-72 hours and 7.7% after 7 days, The success rate fell with increasing time after upper gastrointestinal bleeding began, 7) The factors which influenced the outcome of upper gastrointestinal bleeding was age, severity of bleeding and episode of bleeding. The overall mortality rate was 9.7%

게르마늄 함유 기능성 쌀 생산을 위한 최적 처리방법 선정

조주식 ( Ju Sik Cho ),박성규 ( Seong Kyu Park ),박우영 ( Woo Young Park ),임종서 ( Jong Sir Lim ),천영석 ( Young Seok Cheon ),서동철 ( Seong Tae Lee ),이성태 ( Seong Yae Lee ),허정수 ( Jong Soo Heo ) 한국토양비료학회 2008 한국토양비료학회 학술발표회 Vol.2008 No.1