• 생명과학회지
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• 제32권1호
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• pp.63-69
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• 2022

Thioredoxin reductase (TrxR) 시스템은 세포 내 산화 환원 반응의 항상성 유지와 신호 전달 경로를 조절하는데 중추적인 역할을 함으로써 세포의 생존과 기능 유지에 필수적이다. TrxR 시스템은 thioredoxin (Trx), TrxR 및 nicotinamide adenine dinucleotide phosphate의 구성요소를 포함하며, TrxR 효소의 촉매 반응에 의해 환원된 Trx는 하위 표적 단백질을 환원시켜 결과적으로 산화적 스트레스에 대한 방어와 세포 분화, 성장 및 사멸을 조절한다. 암세포는 무한한 세포 증식과 높은 대사율로 인해 과도하게 생성된 활성산소종을 소거하기 위해 세포 내 항산화능을 향상시켜 세포의 생존을 유지하는 반면, 항산화 시스템에 대한 의존도 및 민감도가 높아 이를 표적으로 한 항암 활성 연구에서 잠재적인 가능성이 있음을 제시한다. 여러 연구 결과에서 TrxR이 다양한 유형의 암에서 높은 수준으로 발현되고 있음이 밝혀졌고, 또한 TrxR 시스템을 표적으로 한 항암 활성에 대한 연구가 증가하고 있다. 따라서 본 총설에서는 세포 내 TrxR 시스템의 기능과 암의 발달 및 진행에서의 역할을 다루고, TrxR 억제제의 항암 활성 및 기전을 검토함으로써 항암 활성 연구에 대한 전략으로 TrxR 시스템의 타당성과 가치를 논하였다.

• 지질공학
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• 제31권4호
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• pp.493-506
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• 2021

액상화 현상이란 지반이 포화된 느슨한 사질토 지반에 지진과 같은 동적하중이 급속히 작용할 때 과잉간극수압이 발생하고, 지반이 유효응력을 상실하고 액체화 되는 현상을 말한다. 액상화 평가를 위한 실내반복시험은 반복삼축압축시험과 반복전단시험을 통하여 확인이 가능하다. 이와 관련하여 본 연구에서는 반복삼축압축시험을 이용한 모래의 상대밀도와 입도분포에 따른 액상화 저항 강도를 확인하고자 하였고, 실험장비의 신뢰도 검증과 결과의 타당성을 확인하고자 기존의 선행연구와 대조하여 비교·분석하였다. 실험결과, 흙의 분류에 상관없이 상대밀도가 증가함에 따라 액상화 저항 강도가 높아짐을 확인하였고, 모래의 입도분포에 따른 액상화 저항강도는 SW에 가까운 SP시료의 액상화 저항강도가 상당히 높게 확인되었다. 또한 세립분 0% 대비 세립분 30%를 분석한 결과, 상대밀도 40~70%까지 증가함에 따라 액상화 저항강도가 5~20% 가까이 감소하였고, 국내 풍화토 지반이 주문진 표준사 대비 액상화 저항 강도가 세립분이 10%일 때는 30% 이상, 세립분이 30%일 때는 50% 이상 낮게 측정되었다.

• Journal of Veterinary Science
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• 제23권5호
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• pp.74.1-74.16
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• 2022

Background: Previous studies have presented evidence to support the significant association between red meat intake and colon cancer, suggesting that heme iron plays a key role in colon carcinogenesis. Epigallocatechin-3-gallate (EGCG), the major constituent of green tea, exhibits anti-oxidative and anti-cancer effects. However, the effect of EGCG on red meat-associated colon carcinogenesis is not well understood. Objectives: We aimed to investigate the regulatory effects of hemin and EGCG on colon carcinogenesis and the underlying mechanism of action. Methods: Hemin and EGCG were treated in Caco2 cells to perform the water-soluble tetrazolium salt-1 assay, lactate dehydrogenase release assay, reactive oxygen species (ROS) detection assay, real-time quantitative polymerase chain reaction and western blot. We investigated the regulatory effects of hemin and EGCG on an azoxymethane (AOM) and dextran sodium sulfate (DSS)-induced colon carcinogenesis mouse model. Results: In Caco2 cells, hemin increased cell proliferation and the expression of cell cycle regulatory proteins, and ROS levels. EGCG suppressed hemin-induced cell proliferation and cell cycle regulatory protein expression as well as mitochondrial ROS accumulation. Hemin increased nuclear factor erythroid-2-related factor 2 (Nrf2) expression, but decreased Keap1 expression. EGCG enhanced hemin-induced Nrf2 and antioxidant gene expression. Nrf2 inhibitor reversed EGCG reduced cell proliferation and cell cycle regulatory protein expression. In AOM/DSS mice, hemin treatment induced hyperplastic changes in colon tissues, inhibited by EGCG supplementation. EGCG reduced the hemin-induced numbers of total aberrant crypts and malondialdehyde concentration in the AOM/DSS model. Conclusions: We demonstrated that EGCG reduced hemin-induced proliferation and colon carcinogenesis through Nrf2-inhibited mitochondrial ROS accumulation.

• 한국수정란이식학회:학술대회논문집
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• 한국수정란이식학회 2002년도 국제심포지엄
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• pp.78-78
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• 2002

The role of heat shock proteins in shielding organism from environmental stress is illustrated by the large-scale synthesis of these protein by the organism studied to date. However, recent evidence also suggests an important role for heat shock protein in fertilization and early development of mammalian embryos. Effects of elevated in vitro temperature on in vitro produced bovine embryos were analysed in order to determine its impact on the expression of heat shock protein 70 (HSP70) by control and frozen-thawed after in vitro fertilization (IVF) or nuclear transfer (NT). The objective of this study was to assess the developmental potential in vitro produced embryos with using of the various containers and examined expression and localization of heat shock protein 70 after it's frozen -thawed. For the vitrification, in vitro produced embryos at 2 cell, 8 cell and blastocysts stage after IVF and NT were exposed the ethylene glycol 5.5 M freezing solution (EG 5.5) for 30 sec, loaded on each containers such EM grid, straw and cryo-loop and then immediately plunged into liquid nitrogen. Thawed embryos were serially diluted in sucrose solution, each for 1 min, and cultured in CRI-aa medium. Survival rates of the vitrification production were assessed by re-expanded, hatched blastocysts. There were no differences in the survival rates of IVF using EM grid, cryo-loop. However, survival rates by straw were relatively lower than other containers. Only, nuclear transferred embryos survived by using cryo-loop. After IVF or NT, in vitro matured bovine embryos 2 cell, 8 cell and blastocysts subjected to control and thawed conditions were analysed by semiquantitive reverse transcription polymerase chain reaction methods for hsp 70 mRNA expression. Results revealed the expression of hsp 70 mRNA were higher thawed embryos than control embryos. Immunocytochemistry used to localization the hsp70 protein in embryos. Two, 8-cell embryos derived under control condition was evenly distributed in the cytoplasm but appeared as aggregates in some embryos exposed frozen-thawed. However, under control condition, blastocysts displayed aggregate signal while Hsp70 in frozen-thawed blastocysts appeared to be more uniform in distribution.

• Nutrition Research and Practice
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• 제17권4호
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• pp.682-697
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• 2023

BACKGROUND/OBJECTIVES: Tibetan tea is a kind of dark tea, due to the inherent complexity of natural products, the chemical composition and beneficial effects of Tibetan tea are not fully understood. The objective of this study was to unravel the composition of Tibetan tea using knowledge-guided multilayer network (KGMN) techniques and explore its potential antioxidant and hypolipidemic mechanisms in mice. MATERIALS/METHODS: The C57BL/6J mice were continuously gavaged with Tibetan tea extract (T group), green tea extract (G group) and ddH2O (H group) for 15 days. The activity of total antioxidant capacity (T-AOC) and superoxide dismutase (SOD) in mice was detected. Transcriptome sequencing technology was used to investigate the molecular mechanisms underlying the antioxidant and lipid-lowering effects of Tibetan tea in mice. Furthermore, the expression levels of liver antioxidant and lipid metabolism related genes in various groups were detected by the real-time quantitative polymerase chain reaction (qPCR) method. RESULTS: The results showed that a total of 42 flavonoids are provisionally annotated in Tibetan tea using KGMN strategies. Tibetan tea significantly reduced body weight gain and increased T-AOC and SOD activities in mice compared with the H group. Based on the results of transcriptome and qPCR, it was confirmed that Tibetan tea could play a key role in antioxidant and lipid lowering by regulating oxidative stress and lipid metabolism related pathways such as insulin resistance, P53 signaling pathway, insulin signaling pathway, fatty acid elongation and fatty acid metabolism. CONCLUSIONS: This study was the first to use computational tools to deeply explore the composition of Tibetan tea and revealed its potential antioxidant and hypolipidemic mechanisms, and it provides new insights into the composition and bioactivity of Tibetan tea.

• Nutrition Research and Practice
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• 제17권5호
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• pp.899-916
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• 2023

BACKGROUND/OBJECTIVES: Oxidative stress is a fundamental neurodegenerative disease trigger that damages and decimates nerve cells. Neurodegenerative diseases are chronic central nervous system disorders that progress and result from neuronal degradation and loss. Recent studies have extensively focused on neurodegenerative disease treatment and prevention using dietary compounds. Heseperetin is an aglycone hesperidin form with various physiological activities, such as anti-inflammation, antioxidant, and antitumor. However, few studies have considered hesperetin's neuroprotective effects and mechanisms; thus, our study investigated this in hydrogen peroxide (H₂O₂)-treated SH-SY5Y cells. MATERIALS/METHODS: SH-SY5Y cells were treated with H₂O₂ (400 µM) in hesperetin absence or presence (10-40 µM) for 24 h. Three-(4,5-Dimethyl-2-thiazolyl)-2,5-diphenyl-2H-tetrazolium bromide assays detected cell viability, and 4',6-diamidino-2-phenylindole staining allowed us to observe nuclear morphology changes such as chromatin condensation and apoptotic nuclei. Reactive oxygen species (ROS) detection assays measured intracellular ROS production; Griess reaction assays assessed nitric oxide (NO) production. Western blotting and quantitative polymerase chain reactions quantified corresponding mRNA and proteins. RESULTS: Subsequent experiments utilized various non-toxic hesperetin concentrations, establishing that hesperetin notably decreased intracellular ROS and NO production in H₂O₂-treated SH-SY5Y cells (P < 0.05). Furthermore, hesperetin inhibited H₂O₂-induced inflammation-related gene expression, including interluekin-6, tumor necrosis factor-α, and nuclear factor kappa B (NF-κB) p65 activation. In addition, hesperetin inhibited NF-κB translocation into H₂O₂-treated SH-SY5Y cell nuclei and suppressed mitogen-activated protein kinase protein expression, an essential apoptotic cell death regulator. Various apoptosis hallmarks, including shrinkage and nuclear condensation in H₂O₂-treated cells, were suppressed dose-dependently. Additionally, hesperetin treatment down-regulated Bax/Bcl-2 expression ratios and activated AMP-activated protein kinase-mammalian target of rapamycin autophagy pathways. CONCLUSION: These results substantiate that hesperetin activates autophagy and inhibits apoptosis and inflammation. Hesperetin is a potentially potent dietary agent that reduces neurodegenerative disease onset, progression, and prevention.

• Composites Research
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• 제36권6호
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• pp.441-447
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• 2023

최근 경량 소재에 대한 수요 증가로 기존 금속과 복합재간 접합 관심이 지대하다. 리벳팅과 같은 볼트 체결인 기계적 결합의 경우 응력 집중, 균열 및 박리가 발생함에 따라 접착제를 사용한 화학적 결합이 주목받고 있다. 본 논문에서는 접착제의 접합강도 향상을 위해 레이저 및 플라즈마 표면처리를 진행하였으며, 이에 대한 접착특성을 평가하고자 한다. 접합강도 실험을 위해 흔히 자동차용 소재로 사용되는 탄소섬유강화플라스틱(CFRP), CR340(Steel)과 Al6061(Aluminum)을 실험 소재로 선정해 레이저 및 플라즈마 표면처리를 진행 후 단축전단강도를 측정하였다. 플라즈마 표면처리 후 CFRP-CR340 및 CFRP-Al6061 이종소재 시편에서 각각 접합강도가 7.3% 및 39.2% 향상되었다. CR340-Al6061 시편은 레이저 표면처리에서 기준 시편대비 56.2% 증가하였다. 플라즈마 표면처리 후 표면자유에너지(SFE)가 향상되었는데 이는 화학반응 메커니즘을 통해 손상을 최소화해 접합강도 향상을 나타낸 것으로 사료된다. 레이저 표면처리는 물리적 표면처리로 거친 접합 표면 생성으로 인해 mechanical interlocking 효과로 인해 접착 강도가 향상된 것으로 사료된다. 본 연구를 토대로 실제 구조물 파손의 대표적인 원인인 피로파손을 예방하기 위해 장기 피로시험을 진행 할 예정이다.

• Biomolecules & Therapeutics
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• 제32권1호
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• pp.154-161
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• 2024

Amyotrophic lateral sclerosis (ALS) is a fatal motor neuron disorder that causes progressive paralysis. L-Citrulline is a nonessential neutral amino acid produced by L-arginine via nitric oxide synthase (NOS). According to previous studies, the pathogenesis of ALS entails glutamate toxicity, oxidative stress, protein misfolding, and neurofilament disruption. In addition, L-citrulline prevents neuronal cell death in brain ischemia; therefore, we investigated the change in the transport of L-citrulline under various pathological conditions in a cell line model of ALS. We examined the uptake of [¹⁴C]L-citrulline in wild-type (hSOD1wt/WT) and mutant NSC-34/ SOD1^G93A (MT) cell lines. The cell viability was determined via MTT assay. A transport study was performed to determine the uptake of [¹⁴C]L-citrulline. Quantitative real-time polymerase chain reaction (qRT-PCR) analysis was performed to determine the expression levels of rat large neutral amino acid transported 1 (rLAT1) in ALS cell lines. Nitric oxide (NO) assay was performed using Griess reagent. L-Citrulline had a restorative effect on glutamate induced cell death, and increased [¹⁴C]L-citrulline uptake and mRNA levels of the large neutral amino acid transporter (LAT1) in the glutamate-treated ALS disease model (MT). NO levels increased significantly when MT cells were pretreated with glutamate for 24 h and restored by co-treatment with L-citrulline. Co-treatment of MT cells with L-arginine, an NO donor, increased NO levels. NSC-34 cells exposed to high glucose conditions showed a significant increase in [¹⁴C]L-citrulline uptake and LAT1 mRNA expression levels, which were restored to normal levels upon co-treatment with unlabeled L-citrulline. In contrast, exposure of the MT cell line to tumor necrosis factor alpha, lipopolysaccharides, and hypertonic condition decreased the uptake significantly which was restored to the normal level by co-treating with unlabeled L-citrulline. L-Citrulline can restore NO levels and cellular uptake in ALS-affected cells with glutamate cytotoxicity, pro-inflammatory cytokines, or other pathological states, suggesting that L-citrulline supplementation in ALS may play a key role in providing neuroprotection.

• 한국임상수의학회지
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• 제10권2호
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• pp.171-184
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• 1993

In Seoul area, there are so many kennel clubs, veterinary hospital, pet establishment and breeding confers that various problems have occurred. They are crowed pet houses, poor sanitation, stress to puppies, sudden environmental changes to puppies and unvaccination against parvovirus, canine distemper virus, parainfluenza virus, infectious hepatitis caused by Adenovirus type I and Leptospira. Several studies were made to survey the infectious agents involved in acute diarrhea of poppies in Seoul are, such as history taking, physical examination, complete blood count and serum chemistry, histopathological finding, bacterial isolation and identification, and hemagglutination test in feces and hemagglutination inhibition test in serum against parvovirus, respectively. The results obtained are summarized as followed. 1. The percent of PCV (30.5$\pm$5.6) and concentration of Total protein(5.0$\pm$0.8) resulted from statistical analysis are significantly lower than normal values (p<0.05), respectively. In addition, fibrinogen (505$\pm$326) was significantly higher an normal value (p<0.001), Band neutrophil (22.9$\pm$12.7) showed signifiant difference (P<0.01). decreased monocyte (3.2$\pm$2.1) and eosinophil (0.7$\pm$0.8) values appeared statistically significant (p<0.001), lymphocyte (16.7$\pm$9), as well. 2. The concentrations of calcium .(8.0$\pm$2.8), glucose (40.1$\pm$31.4), and albumin (2.0$\pm$0.39) were lower than normal values (p<0.01, p<0.01, p<0.001), respectively. Also Inorganic phosphate (7.1$\pm$2.4), pH (p<7.9f:0.2), and Blood Urea Nitrogen (40.41=37.1) were significantly higher than normal values (p<0.001, p(0.001, p<0.05), respectively. 3. Simple and mixed infections occupied 18% and 82% in the distribution of causes in puppies with acute diarrhea, respectively. 4. As puppies got older, incidence of acute diarrhea caused by Staphylococcus aureus was decreased to 13% and infection of canine distemper virus was increased to 53%, but E coli and canine parvovirus always showed high frequency of outbreak in the body weight ranged from 35g to 7.8Kg. 5. As showed in table 5, infections of E coli and Canine Parvovirus showed high outbreak regardless of the age which is classified into three stages, 35~50 day, 60 day and 75~day to 1 year, canine distemper virus appeared increased, but in case of Staphylococcus aureus, visa versa. 6. In comparison wi methods for the laboratory diagnosis diagnosis parvovirus, Hemagglutination test showed positive reaction in 25% and mean serum antibody titer measured by Hemagglutination inhibition test showed 2779 (n=20). In addition, positive reaction was 90% (18/20). 7. In histopathological studies, enteritic and pneumonic lesions were indicated in 53.7% and 39.5% of samples, respectively. 8. Etiologic diagnosis based on the history taking, clinical signs and histopathological findings in puppies with acute diarrhea and vomiting indicated that 50% of puppies were infected by canine parvovirus and distemper virus. 9. In the parasitological examination made by simple flotation with saturated zinc sulfate tour parasites found were Isospora canis, Toxocara canis, Ancylostoma spp and Toxocara spp. Isospora canis and Toxocara canis were more frequently found among those parasites of diarrhoeic causes in puppies ranged from 35 days to 1 year. Their infestation rates were 15% and 13% respectively.

• 펄프종이기술
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• 제48권2호
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• pp.34-45
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• 2016

Global warming and climate change have been caused by combustion of fossil fuels. The greenhouse gases contributed to the rise of temperature between $0.6^{\circ}C$ and $0.9^{\circ}C$ over the past century. Presently, fossil fuels account for about 88% of the commercial energy sources used. In developing countries, fossil fuels are a very attractive energy source because they are available and relatively inexpensive. The environmental problems with fossil fuels have been aggravating stress from already existing factors including acid deposition, urban air pollution, and climate change. In order to control greenhouse gas emissions, particularly CO2, fossil fuels must be replaced by eco-friendly fuels such as biomass. The use of renewable energy sources is becoming increasingly necessary. The biomass resources are the most common form of renewable energy. The conversion of biomass into energy can be achieved in a number of ways. The most common form of converted biomass is pellet fuels as biofuels made from compressed organic matter or biomass. Pellets from lignocellulosic biomass has compared to conventional fuels with a relatively low bulk and energy density and a low degree of homogeneity. Thermal pretreatment technology like torrefaction is applied to improve fuel efficiency of lignocellulosic biomass, i.e., less moisture and oxygen in the product, preferrable grinding properties, storage properties, etc.. During torrefacton, lignocelluosic biomass such as palm kernell shell (PKS) and empty fruit bunch (EFB) was roasted under an oxygen-depleted enviroment at temperature between 200 and $300^{\circ}C$. Low degree of thermal treatment led to the removal of moisture and low molecular volatile matters with low O/C and H/C elemental ratios. The mechanical characteristics of torrefied biomass have also been altered to a brittle and partly hydrophobic materials. Unfortunately, it was much harder to form pellets from torrefied PKS and EFB due to thermal degradation of lignin as a natural binder during torrefaction compared to non-torrefied ones. For easy pelletization of biomass with torrefaction, pellets from PKS and EFB were manufactured before torrefaction, and thereafter they were torrefied at different temperature. Even after torrefaction of pellets from PKS and EFB, their appearance was well preserved with better fuel efficiency than non-torrefied ones. The physical properties of the torrefied pellets largely depended on the torrefaction condition such as reaction time and reaction temperature. Temperature over $250^{\circ}C$ during torrefaction gave a significant impact on the fuel properties of the pellets. In particular, torrefied EFB pellets displayed much faster development of the fuel properties than did torrefied PKS pellets. During torrefaction, extensive carbonization with the increase of fixed carbons, the behavior of thermal degradation of torrefied biomass became significantly different according to the increase of torrefaction temperature. In conclusion, pelletization of PKS and EFB before torrefaction made it much easier to proceed with torrefaction of pellets from PKS and EFB, leading to excellent eco-friendly fuels.