Strain Distributions of Plane-Strained and Simple-Sheared Al–Mg Alloy

Hyeon‑Woo Son,Jae‑Cheol Lee,Hyun Soon Park,Soong‑Keun Hyun 대한금속·재료학회 2021 METALS AND MATERIALS International Vol.27 No.11

Strain distribution in plane-strained (rolling) and simple-sheared (torsion) Al–Mg alloy has been estimated using both X-rayline profile analysis and electron backscatter technique. The strain analyses under unified texture distribution by orientationrotation showed that torsion has relatively homogeneous strain distribution regardless of texture component in contrast toinhomogeneous strain in rolling. In addition, annealing texture of torsion has more random texture than inhomogeneousrolling texture. Lower texture difference index in annealed torsion specimens suggest homogeneous strain distribution insimple shear has a higher resistance to strain-induced boundary migration, which has been known to be main reason forstrong development of ND||⟨100⟩ component during annealing of rolled Al sheet.

Inhibition of oxidative stress induced‑cytotoxicity by coptisine in V79‑4 Chinese hamster lung fibroblasts through the induction of Nrf‑2 mediated HO‑1 expression

Hyeon‑Gyun Jo,Cheol Park,이혜숙,Gi‑Young Kim,Young‑Sam Keum,Jin Won Hyun,Taeg Kyu Kwon,Yung Hyun Choi,Su Hyun Hong 한국유전학회 2021 Genes & Genomics Vol.43 No.1

Background Coptisine is a natural alkaloid compound and is known to have multiple benefcial efects including antioxidant activity. However, whether it can protect lung fbroblasts from oxidative damage has not been studied yet. Objectives To investigate the potential inhibitory efect of coptisine against oxidative stress in V79-4 lung fbroblast cells. Methods V79-4 cells were treated with H2O2 (1 mM) in the presence or absence of coptisine (50 µg/ml), N-acetyl cysteine (NAC, 10 mM) or zinc protoporphyrin IX (ZnPP, 10 µM) for the indicated times. The alleviating efects of coptisine on cytotoxicity, cell cycle arrest, apoptosis, reactive oxygen species (ROS) production, DNA damage, mitochondrial dynamics, and inhibition of ATP production against H2O2 were investigated. Western blot analysis was used to analyze the expression levels of specifc proteins. Results Coptisine inhibited H2O2-induced cytotoxicity and DNA damage by blocking abnormal ROS generation. H2O2 treatment caused cell cycle arrest at the G2/M phase accompanied by increased expression of cyclin-dependent kinase (Cdk) inhibitor p21WAF1/CIP1 and decreased expression of cyclin B1 and cyclin A. However, these efects were attenuated in the presence of coptisine or NAC. Coptisine also prevented apoptosis by decreasing the rate of Bax/Bcl-2 expression in H2O2-stimulated cells and suppressing the loss of mitochondrial membrane potential and the cytosolic release of cytochrome c. In addition, the activation of nuclear factor-erythroid-2-related factor 2 (Nrf2) and heme oxygenase-1 (HO-1) was markedly promoted by coptisine in the presence of H2O2. However, zinc protoporphyrin IX, a potent inhibitor of HO-1, attenuated the ROS scavenging and anti-apoptotic efects of coptisine. Conclusions Based on current data, we suggest that coptisine can be used as a potential treatment for oxidative stress-related lung disease.

Cryptococcal 뇌막염이 병발된 수막 암종증 1예

안병철,고지영,이현옥,최진영,권오상,박용욱 중앙대부설한국의과학연구소 1990 한국의과학 Vol.22 No.1

당근의 고체배양에서 체세포발생중 세포내 생화학적 변화

차현철,박희승 단국대학교 1996 論文集 Vol.30 No.-

Some important macromolecules in The cells of embryogenic(E-) and non-embryogenic(NE-) calli of car-rot(Daucus carata cv. Daepooong-ochon) were quantitatively measured periodically during culture of 5 weeks on solid medium. The transfer of the callus from the MS medium with phytohormones to phytohormone-free medium induced embyroid formation at 10 days culture. And the condents of some solutes were changed dramatically at embryoid forming time. In other words, free amino acid and soluble protein contents were reached to maximum at 8th day after culture in E-callus cells. On the contrarily reducing suger content was decreased at early time leading to minimum value at 8th day on both calli imspite of the double value in E-callus comparing with Ne-callus at that time. The higher con-tents of sugars in E-callus may contributed by energy budgets needed to initiate embryoid formation. The activity of peroxidase and its specific activity was higher in E-callus than NE-callus at embryoid forming time and DNA content was steadly increased during that time. RNA content also was increased to reach peak at 16th day in NE-callus, at 24th day in E-callus. After that, the content was decreased to the original levels. In conclusion, the metabolism in the parenchyma cells may be changed dramatically in order to initiate the embryoid formation.

SD Rats를 이용 1-hexene의 흡입독성 연구

김현영,임철홍,정용현,이권섭,이성배,이준연,한정희,전윤석,이용묵 한국환경독성학회 2001 환경독성보건학회지 Vol.16 No.4

The purpose of this study was to investigate the acute (4 hours) and repeated-dose (6 hours a day, 5 days a week, 4 weeks) toxic effects of I -hexene on Sprague- Dawley (SD) rats which were treated by inhalation. The results were as follows; I. The median lethal concentration (LC_(50)) was estimated 52,694 ppm (confidence limit 95%; 49,494~55,447 ppm) in acute inhalation. Abnormal clinical signs related to the l-Hexene were not observed with the acute inhalation dose. Gross findings of necropsy revealed on evidence of specific toxicity related to the 1-hexene, II. By repeated inhalation exposure the body weight of male were more or less reduced by the dose of 2,500 ppm and 5,000 ppm compared with control group. However there were no significant variation hematology and blood biochemistry for the exposed rats compared with the control rats. Abnormal clinical signs and gross findings of necropsy related to the 1-hexene were not shown. In conclusion when we exposed I-hexene to SD rats for 4 weeks, 5 days per week, 6 hours per day, the Lowest observed effect level (LOEL) was over 2,500 ppm and Non observed effect level (NOEL) was below 500 ppm.

複極性固定層 電解槽에 의한 크롬 廢液의 電解處理(Ⅲ)

張哲鉉 大田工業大學 1991 한밭대학교 논문집 Vol.8 No.2

For the purpose of electrolytic treatment of wastewater containing chromic ion, the Bipolar Packed Bed Electrode(BPBE) Cell of batch and continuous type was considered and experimented. Some results this study were summarized as follows : 1) When the electrolysis was carried out in the cell packed activated carbon from coconut shell, the reaction rate become higher than those in monopolar cell. 2) As applied volatage and particle size were increased, the reaction rate increased and chromic metal deposited on packed material. 3. As granular activated carbon packed in BPBE Cell, coconut shell was superior to lignite and the removal efficiency was the highest when the activated carbon was 4/6 mesh, the voltage was 20V. 4. When the artificial wastewater containing chromic ion was electrolyzed in BPBE Cell, the removal efficiency was over 98% (continuous type) .

전유전체 서열 분석과 가시화를 위한 워크벤치 개발과 응용

최정현,진희정,김철민,장철훈,조환규 한국유전학회 2002 Genes & Genomics Vol.24 No.2

An increasing number of genome sequencing projects results in explosive growth of whole genome sequences. Furthermore the number of studies on the functions of individual genes has also been rapidly increased. However on-memory algorithms are not applicable to the analysis of whole genome sequences, since the size of individual whole gene a ranges from several million base pairs to hundreds billion base pairs. In order to effectively manipulate the huge sequence data, it is necessary to use the indexed data structure for external memory. In this paper, we introduce the development and application of the workbench for the analysis and visualization of whole genome sequences using string B-tree that is suitable for the analysis of huge data. This system consists of two main parts, the analysis query part and the visualization part. The query system supports various transactions such as pattern matching, k-occurrence, and k-mer analysis. The visualization system helps biologists to easily understand whole genome structure and specificity by various kinds of visualization such as whole genome sequence viewer, annotation viewer, CGR (Chaos Game Representation) viewer, k-mer viewer, RWP (Random Walk Plot) viewer, and map viewer. We can find the relationships among organisms, support gene prediction in a genome, and study the function of junk DNA using our workbench. In this paper, we apply our workbench to investigating specific sequence such as avoided sequence, common sequence, and classifiable sequence.

갈륨합금과 고동 아말감 합금의 물리적 성질 비교

김현철,이희주,허복 大韓齒科保存學會 1998 Restorative Dentistry & Endodontics Vol.23 No.1

The purpose of this study was to compare the physical properties between high copper amalgam and gallium restorative material. In this study, the specimens for the 4 experimatal groups(Valiant, Valiant PhD, Gallium Alloy GF Ⅱ, Gallium Alloy GF Ⅱ triturated with some addition of alcohol) were prepared in the manner of which stated in ADA specification No. 1 for amalgam alloy. And then, measured and compared the value of compressive strength, creep, and dimensional change during hardening of each sample. The results were as follows: 1. In the compressive strength, the valiant-lathe cut type high copper amalgam-had the highest value of strength(p<0.05), and the Valiant PhD-admixed type high copper amalgam-showed the higher value of strength than the Gallium Alloy GF Ⅱ(p<0.05) but had no significant difference with Gallium Alloy GF Ⅱ triturated with some addition of alcohol(p>0.05). 2. In the creep, the Valiant PhD showed the highest value of creep(p<0.05), but there was no significant difference between Gallium Alloy GF Ⅱ and Valiant(p>0.05). 3. In the dimensional change during hardening, no two groups were significantly different at the 0.050 level. 4. There was no significant difference between Gallium Alloy GF Ⅱ and the same material which was triturated with some addition of alcohol(p>0.05).

S.D. Rats를 이용 1, 1-Dichloro-1-fluoroethane의 아민성 흡입독성 연구

김현영,이성배,임철홍,김철우,점용현,한정희,전윤석,최수영,강대봉,이용묵 한국환경독성학회 2002 환경독성보건학회지 Vol.17 No.1

There were no specific effects for test materials on Sprague-Dawley (S.D.) rats in clinical symptoms, amounts of food intakes, weight changes, laboratory findings, and pathology after whole body l, l-Dichloro-1 -fluoroethane (used as coolant, metal cleaner and solvents) exposure(0, 1,500, 3,000, and 6,000 ppm) for 13 weeks (6 hour/day, 5 days/week). However, the loss of capillary vessels in eyeball (pupil) was observed in a female rat among 6,000 ppm group. Though there was a tendency for MCHC (Mean Corpuscular Hemoglobin Concentration) in rat to be decreased (p<0.05), it was not regarded as abnormal because the values were within normal limits. In asthma-stimulation related evaluations, there was also a tendency for inflammatory cell counts in bronchoalveolar lavages to be increased. But it had no statistical significance, and also no dependency on sex and the exposed concentration. Based on this result, the non observed effect level (NOEL) induced by 1, 1-Dichloro-l -fluoroethene inhalation was evaluated in groups with 3,000 ppm below (S .D. Rats, 13 weeks). Finally, it was concluded that the short term exposal of 1, 1-Dichloro-l-fluoroethane is not considered as a asthma stimulant by inhalation despite of some study limitations such as test animals use and short-term exposure .

크롬(Ⅵ)의 체내 흡수와 소실속도에 관한 연구

김현영,이성배,임철홍,이권섭,정용현,이종성,한정희,전윤석,황호순,이용묵 한국산업위생학회 2003 한국산업보건학회지 Vol.13 No.1

The CrO3 mostly used in plating. metal surface disposal, leather, cosmetic manufacturing, as an experiment material by repeatedly inhaling and exposure the male S.D. rats at a 0.00, 0.2., 0.50, 1.25 mg/㎡ concentration(particle size: 0.5-0.5 aerosol)6hours a day, 5day a week in 13weeks comparing with 2weeks, 8weeks of recovery group about the noxiousness of the experiment animal and the reduce scale of the CrO3 in the internal organ especially in blook and respiratory organ with the period of convalescent and clearance. The experiment results which we received are as follows. 1. In blood the RBC, HGB and HCT experiment, rats with 0.20, 0.50 mg/㎡ concentration showed that there were some decreases but not dependent. The kidneys absolute weight compared with control group was reduced intentionally(p〈0.05) and the lungs absolute weight compared with control group showed intentional increase(p〉0.05). 2. After the exposure of the experiment material, the whole blook, l\blood plasma and red blood cell in blood by (x): the period of convalescent, per (y); the decreasing of Cr concentration, was y=66.51 e -0.057x, y=67.2 e-0.101x, y=70.01 e-0.030 in 0.50 mg/㎡ exposure concentration by calculating the clearance coefficient of correlation, and the half life (day)was estimated 12.0, 6086, 23.0 each. 3, After the exposure of the experiment material, the experiment animals lung, liver and kidneys by(x); the period of convalescent, per (y); the decreasing of Cr conentration, was y=1808 e-0.00493x, y=12.02e-0.0297x, y=67.61 e-0.0292x in 0.50mg/㎡ exposure concentration by calculating the clearance coefficient of correlation, and the half life(day)was estimated 140.6, 23.3, 23.7, each, and including lung, liver with all of the experiment internal organs, the Cr clearance decreased as the exposure concentration increased.