NR과 SBR 가황물의 경도와 강성도에 대한 온도의 영향

진현호 ( Hyun Ho Jin ),홍창국 ( Chang Kook Hong ),조동련 ( Dong Lyun Cho ),강신영 ( Shin Young Kaang ) 한국고무학회 2007 엘라스토머 및 콤포지트 Vol.42 No.3

본 연구에서는 고무제품의 수치 안정성과 성능유지에 직접적으로 영향을 미치는 중요한 특성 중 하나인 온도변화에 따른 고무재료의 경도변화를 고찰하였다. 새롭게 제작된 International Rubber Hardness Degree(IRHD, Normal type) 경도측정 시험기를 사용하여 미충전된 NR과 SBR시편의 여러 온도에서 경도변화를 측정하였으며 Young`s modulus 값과 비교하였다. NR과 SBR 모두 유리전이온도 근처에서 경도와 Young`s modulus의 급격한 변화를 보였다. 온도가 증가함에 따라 경도와 Young`s modulus 값이 증가하는 경향을 보였으며 이는 분자의 운동성과 엔트로피 영향으로 해석할 수 있다. 카본블랙과 실리카가 충전된 NR과 SBR의 경우 충전제의 함량이 증가함에 따라 경도에 미치는 온도의 영향이 감소함을 관찰하였다. Hardness of rubbery materials, which is important for dimensional stability and product performance, was investigated upon temperature change in this study. A newly developed IRHD (International Rubber Hardness Degree) tester was used to measure the hardness changes of NR and SBR specimens at various temperatures and the hardness values were compared with the Young`s modulus. The hardness and Young`s modulus of NR and SBR showed an abrupt change near the glass transition temperatures. The hardness and Young`s modulus were increased by increasing temperature due to the increased random chain conformation of molecules. The effect of temperature on hardness and Young`s modulus of NR and SBR specimens filled with carbon black and silica was decreased by increasing filler content.

Critical role of bile acid (BA) in the cellular entry and permissiveness of Hepatitis B virus in vitro

Hong‑Jai Lee,Bo‑Young Shin,Jae‑Seung Moon,Ailyn Fadriquela,Selikem Abla Nuwormegbe,Chun‑Chang Ho,Jin‑Su Shin,Jee‑Sang Yoon,Sang‑Kyou Lee,Soo‑Ki Kim 대한독성 유전단백체 학회 2020 Molecular & cellular toxicology Vol.16 No.3

Background Lack of universal replication system for hepatitis B virus with narrow host range and organ tropism has hampered to uncover the pathogenesis of HBV. Previously, we reported the essentiality of humoral milieu and its components toward HBV and hepatitis C virus survival/viability in vitro. Of these components, the precise role of enterohepatic humoral milieu such as bile acid (BA) on HBV cultivation in vitro and in vivo is unknown. Objective We explored whether BA, specifically taurochenodeoxycholic acid (tCDCA) would directly regulate the viral DNA and surface antigen expression of HBV in vitro, consequently rendering HBV to enter into human or murine immortalized hepatocytes, and non-hepatocytes. Result We found that higher concentration of taurochenodeoxycholic acid (tCDCA) is able to preserve the genomic stability of HBV in cell-free DMEM, showing higher the surface antigenicity than taurocholic acid (tCA). In line, we found that in vitro cell culture condition (100 μmol/L of tCDCA coupled with 1 × 108 g e/mL HBV) would be optimal for HBV entry into target cells. Using this, human (HepG2, Huh7), and rodent (Hepa1c1c7, H4-II-E) hepatoma cell lines were infected by HBV, as evidenced by the presence of HBV biomarkers (HBsAg, and HBV DNA in culture supernatant, as well as HBcAg in cell). Further, cellular entry test revealed that HBV is able to infect 12 different non-hepatic cell lines regardless of species, and organ/tissue, consequently reproducing progeny as confirmed by HBV biomarkers. Last, reinfection test showed that the progenies of HBV from immortalized HepG2, and Hepa1c1c7 cells are able to enter into each or vice versa naïve HepG2, and Hepa1c1c7 cells with or without BA. Conclusion This study demonstrates that enterohepatic humoral milieu such as BA, specifically tCDCA would directly regulate HBV DNA and its surface antigen expression in vitro, consequently rendering HBV to enter into human or murine immortalized hepatocytes, and non-hepatocytes. This is the first note to render HBV permissive to human or rodent hepatic and non-hepatic cells via sole manipulation of humoral milieu, thus establishing the platform for in vitro robust replication system of HBV.

인터넷 중독 청소년들의 정신병리 및 대처 방식

안영균(Young Kyun Ahn),신영철(Young Chul Shin),고복자(Bok Ja Koh),심진현(Jin Hyun Shim),김범조(Bum Jo Kim),이승민(Seung Min Lee),이길홍(Kil Hong Lee) 한국중독정신의학회 2005 중독정신의학 Vol.9 No.1

This study was conducted to investigate the differences in psychopathology and coping strategies among internet addictors, over users and non addictors in high school students. Subjects were 273 high school students in Seoul city. Self rating questionnaires included demographic data, Young’s Internet Addiction Scale, SCL-90-R, Beck Depression Inventory, Spielberger State-Trait Anxiety Inventory, and The Way of Coping Strategy. Subjects were classified into 3 groups (addiction, over use, non addiction) by Internet Addiction Scale score. Prevalence of internet addiction was 4.3% and male adolescents were more addictive than female. Students who were mainly involved with internet chatting or game showed higher internet addiction score. The addiction group and over use group showed higher level of somatization, obsession, interpersonal sensitivity, depression, anxiety, hostility, and paranoia than non-addicted group. Addiction group and over use group used passive coping strategies more frequently in the stressful situation than nonaddicted group. Also, the regression analysis for finding out causal factors that predicts internet addiction showed that emotion relieving strategy were important variable which predict internet addiction. Interpersonal sensitivity and emotion relieving coping strategy was important to predict addiction. This study showed that problematic internet use was closely associated with psychopathology and psychiatric comorbidity. And high interpersonal sensitivity and emotion relieving coping strategy were related with internet addiction in adolescence.

야뇨증 환아들의 심리사회적 특성에 대한 다기관 연구 : 행동 및 정서 문제를 중심으로

조수철,김재원,신민섭,황준원,한상원,박관현,이상돈,김경도,김건석,서홍진,이유식,정재용,김영균,문두건,남궁미경,한창희,조원열,김영식,배기수,이종국,정우영,신의진 大韓神經精神醫學會 2005 신경정신의학 Vol.44 No.6

Objectives : The aim of this study was to examine the behavioral and emotional problems associated with nocturnal enuresis in Korean children. Methods : Three hundred eighteen children with nocturnal enuresis, together with their parents, completed the Child Behavior Checklist (CBCL), Disruptive Behavior Disorder Scale according to DSM-IV (DBDS), Children's Depression Inventory (CDI), State-Trait Anxiety Inventory for Children (STAIC), and Piers-Harris Children's Self-Concept Scale (PHCSC). Ninety-three normal students were selected as the control group. Results : Compared to the normal control group, the mean scores with regard to the withdrawn, social problems, attention problems, delinquent behavior, aggressive behavior, externalizing problems and total problems profiles were significantly higher in the nocturnal enuresis group according to the CBCL results. The nocturnal enuresis group also scored significantly higher in the ADHD and ODD profiles of the DBDS. The nocturnal enuresis group was more depressed and anxious than the control group according to the results of the CDI and STAI. The mean score of the PHCSC was significantly lower in the nocturnal enuresis group when compared to the normal control group. Conclusion : The results of this study suggest that children with nocturnal enuresis in Korea have clinically relevant behavioral and emotional problems. The findings support the link between nocturnal enuresis and psychopathology in Korean children.

연령증가에 따른 혈압요소들의 좌심실비대 및 관동맥질환과의 관련성

박재석,박창규,박미영,박재형,김용현,나진오,신성희,서순용,홍순준,박성미,임홍의,김응주,서홍석,오동주,노영무 대한순환기학회 2004 Korean Circulation Journal Vol.34 No.2

고분자형 자외선 안정제를 함유한 SBR과 NR의 UV 노화 거동에 관한 연구

남경태 ( Kyoung Tae Nam ),홍창국 ( Chang Kook Hong ),채규호 ( Kyu Ho Chae ),강신영 ( Shin Young Kaang ) 한국고무학회 2006 엘라스토머 및 콤포지트 Vol.41 No.3

본 연구에서는 고분자형 자외선 안정제 DGEBA-HALS의 광분해 억제 효과를 평가하기 위해 SBR과 NR 고무를 사용하여 광안정제 첨가에 따른 UV 조사 영향을 고찰하였다. 이를 위해 광안정제를 첨가하지 않은 배합고무, 사용화된 광안정제인 Cyabsorb UV-3529를 첨가한 배합고무, 그리고 고분자형 DGEBA-HALS를 첨가한 배합고무의 영율, 인장장고, blow-off 변형, 가교밀도 측정을 통한 시편의 물리적 특성변화 등을 관찰하였다. UV 조사 후 모든 시편에서 영율이 증가하였으며 인장강도는 광안정제를 첨가한 시편이 첨가하지 않은 시편보다 우수했다. 특히 NR의 경우 DGEBA-HALS 첨가 시 인장강도가 향상되었다. Blow-off 변형 실험결과도 영율 실험 결과와 비슷하였다. UV-vis transmissinon spectra를 통한 SBR 배합고무의 투과도를 조사한 결과 광안정제를 첨가함으로써 약 4%의 향상된 투과도를 보였다. Cyabsorb UV-3529와 DGEBA-HALS의 첨가는 비슷한 경향의 투과도를 나타내었다. SEM을 통해 시편의 표면을 관찰한 결과 광안정제를 첨가함으로써 UV 조사에 의한 균열의 크기가 작아짐을 알 수 있었고, 특히 DGEBA-HALS는 상용화된 Cyabsorb UV-3529 보다 더 좋은 광분해 안정효과를 갖는 것을 확인할 수 있었다. The retardation effects of a new polymeric UV stabilizer, DGEBA-HALS, on the UV degradation of SBR and NR were investigated in this study. The UV degradation behaviors of three different rubber compounds, without any photostabilizer and with commercial Cyabsorb UV-3529 and DGEBA-HALS, were compared. Also, the physical characteristics such as Young`s modulus, tensile strength, blow-off deformation and crosslink density were examined. The Young`s modulus was increased by UV irradiation for all samples, and the tensile strength, after UV irradiation, of the compound with UV stabilizer was better than that of the compound without stabilizer. Especially, the tensile strength of UV irradiated NR was improved by adding DGEBA-HALS. The results of blow-off deformation were in accord with those of Young`s modulus. The degree of transmission of SBR compounds obtained from UV-vis transmission spectra was improved about 4% by adding the UV stabilizer. Commercial Cyabsorb UV-3529 and DGEBA-HALS showed similar trends of transmission. The SEM photographs of SBR surface showed that the size of cracks created by UV irradiation became smaller by adding UV stabilizer. In particular, it is observed that the stabilization effect of DGEBA-HALS was better than that of commercial Cyabsorb UV-3529.

Nifedipine 투여가 선천성 고혈압 쥐의 CYP1A1과 2B1 유도에 미치는 영향

홍영숙,김형래,박혜영,배영숙,박상신 梨花女子大學校 醫科大學 醫科學硏究所 1995 EMJ (Ewha medical journal) Vol.18 No.3

Cytochrome P-450(CYP) enzymes are important in catalyzing the hiotransffrmation on manyendogeneous compounds and xenobiotics, including drugs and carcinogens. In the presentstudy, effect of nifedipine a voltage dependent calcium channel blocker on the induction ofCYP1A1 and 2B1 was investigated. Change of CYP1A1 and 2B1 activities were measuredby using specific enzyme activities and Western blot analysis. CYP1A1, as quantified by ethoxyresorufin-0-deethylase activity and Western blot with monoclonal antibody 1-7-1, increasedin liver microsome of nifedipine-treated spontaneous hypertensive rat(SHR. 30mg/kg.b.w, twicea day for 3days) but not in kidney microsome. CYP2B1, as quantified by benzyloxyresorufin-O-dealkylase activity and Western blot wit]1 monoclonal antibody 2-66-3, markedly increasedin liver microsome of nifedipine-treated SHR but slightly in kidney microsome. The resultsdemonstrate that nifedipine is a potent inducer of CYP2B1 in SHR.

보건교육 내용에 관한 지식 및 흥미에 관한 연구 : 일부 사범대학생을 중심으로 Focusing on the Subjects of Teachers' University Students

홍춘실,박영신 충남대학교 의과대학 지역사회의학연구소 1988 충남의대잡지 Vol.15 No.2

This research was conducted to help select and categorize the suitable health education contents for the health curriculum and health education program. The purpose of this study is to provide a useful information about the health knowledge and health interest of teachers' university students to select a recommendable planning, scope, and contents of health education by a comparative analysis between male and female students, and between departments. The tool for this study was questionaire. The number of items is ninty, 30 of health knowledge and 60 of health interest. And they are subgrouped under eight categories. The items were worked out by me based on the contents of health education subject for general education of many colleges, and were complemented by a preliminary investigation. The subjects for this study were chosen among 548 collegians in K National Teachers' University. Data were collected for thirteen days from November 24 to December 6, 1986 and were analyzed by the SPSS computer program. The results of this study are as follows: 1. The most well-known area of health education contents regardless of sex is "Environments and Health Hazards" and the most ignorant area is "Disease Control". Comparing the degree of health knowledge between male and female students group mean score of females is significantly higher than that of males. (t=8.44, d. f=546, P<0.01) Comparing the departmental degree of health knowledge, there is no significant difference in the mean score between humanities department and natural 'science department. However, the mean score of arts and athletics department is significantly lower than that of humanities department and natural science department. (.P<0.01) 2. The most interested area among health education contents in both males and females is "Health Maintenance and Promotion", and the least interested area is "Community Health". Comparing the degree of health interest between male and females studenst, group mean score of females is significantly higher than that of males. (t=1.99, d. f=546, P<0. 01) The degree of departmental health interest in nearly same in 7 area, but the degree of health interest of arts and athletice department in "Body structure and Function" areais significantly higher than that of humanities and natural science department. (P<0.01) 3. The correlation between health knowledge and health interest is found significant only in the case of female students of natural science department. (r=0.20, P<0.05) The correlation between health knowledge and health interest is also significant in "Health Maintenance and Promotion" area : (r=0.13, P<0.01) 4. There's no significant difference in health knowledge and interest from whichever source they acquire health knowledge. Health knowledge is acquired mostly newspapers and magazines (39%).

나노 세리아 슬러리를 이용한 Stainless steel 304의 MR Polishing 특성에 관한 연구

홍광표,신봉철,김동준,조명우,신영재 한국공작기계학회 2008 한국공작기계학회 춘계학술대회논문집 Vol.2008 No.-

An finishing process using magnetorheological fluid has been developed as a new precision finishing technique to obtain a fine metal surface. Therefore, magnetorheological fluids has been used for micro polishing and micro part. The applied material is 304 stainless steel. It is widely used in the semiconductor machinery and aerospace industries because of high corrosion resistance. For MR polishing process, MR fluids was consisted of carbonyl iron, DI-water and nano slurry ceria(Celexis cx 94s slurry). The wheel speed and electric current were chosen as the variables for analyzing the characteristics of MR polishing process. In the results, the surface roughness according to the variation of wheel speed was analyzed , and it was obtained 1.393nm surface roughness.

안와내벽의 단독외향골절에서 골절정도와 안구함몰정도와의 관계

진홍률,신시옥,추무진,최영석,양상권,김종욱 대한이비인후과학회 1998 대한이비인후과학회지 두경부외과학 Vol.41 No.5