• 한국기계가공학회지
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• 제20권1호
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• pp.42-47
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• 2021

Recently, many structures using lightweight materials have been developed. This study was conducted by using Al6061-T6 and carbon fiber reinforced plastic (CFRP), two common lightweight materials. In addition, the failure characteristics of an interface bonded between a single material and a heterogeneous bonding material were analyzed. The specimens bonded with CFRP and Al6061-T6 were utilized by the combination of the heterogeneous bonding material. The specimens had a double cantilevered shape and the bonding between the materials was achieved by applying a structural adhesive. The experiments were conducted in opening mode: the lower part of the samples was fixed, while their upper part was subjected to a forced displacement of 3 mm/min by using a tensile tester. Under the tested amount of strength, energy release rate, and considering the specimens' fracture characteristics in opening mode, the specimen "CFRP-Al" presented the maximum stress, followed by "Al" and "CFRP". We can hence conclude that the inhomogeneous material "CFRP-Al" is useful for the construction of lightweight structures bonded with structural adhesive.

• BMB Reports
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• 제55권10호
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• pp.494-499
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• 2022

PTEN-induced putative kinase 1 (PINK1) is a serine/threonine kinase that phosphorylates several substrates and exerts neuroprotective effects against stress-induced apoptotic cell death. Mutations in PINK1 have been linked to autosomal recessive forms of Parkinson's disease (PD). Mitophagy is a type of autophagy that selectively promotes mitochondrial turnover and prevents the accumulation of dysfunctional mitochondria to maintain cellular homeostasis. Toll-interacting protein (Tollip) was initially identified as a negative regulator of IL-1β receptor signaling, suppressing inflammatory TLR signaling cascades. Recently, Tollip has been reported to play a role in autophagy and is implicated in neurodegeneration. In this study, we determined whether Tollip was functionally linked to PINK1-mediated mitophagy. Our results demonstrated that Tollip promoted the mitochondrial processing of PINK1 and altered the localization of PINK1, predominantly to the cytosol. This action was attributed to increased binding of PINK1 to mitochondrial processing peptidase β (MPPβ) and the subsequent increase in MPPβ-mediated mitochondrial PINK1 cleavage. Furthermore, Tollip suppressed mitophagy following carbonyl cyanide m-chlorophenylhydrazone-induced mitochondrial dysfunction. These findings suggest that Tollip inhibits mitophagy via the PINK1/parkin pathway upon mitochondrial damage, leading to the blockade of PINK1-mediated neuroprotection.

• Journal of Microbiology and Biotechnology
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• 제32권12호
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• pp.1547-1552
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• 2022

β-Amyrin is a pentacyclic triterpene widely distributed in leaves and stems worldwide. The ability of β-amyrin to induce the production of reactive oxygen species (ROS) in microorganisms suggests its potential as an antimicrobial agent. Thus, this study aimed to elucidate the antibacterial mode of action of β-amyrin. We treated Escherichia coli cells with β-amyrin and found that it triggered ROS accumulation. Excessive stress caused by ROS, particularly hydroxyl radicals, induces glutathione (GSH) dysfunction. GSH protects cells from oxidative and osmotic stresses; thus, its dysfunction leads to membrane depolarization. The resultant change in membrane potential leads to the release of apoptotic proteins, such as caspases. The activated caspases-like protein promotes the cleavage of DNA into single strands, which is a hallmark of apoptosis-like death in bacteria. Apoptotic cells usually undergo events such as DNA fragmentation and phosphatidylserine exposure, differentiating them from necrotic cells, and the cells treated with β-amyrin in this study were positive for annexin V and negative for propidium iodide, indicating apoptosis-like death. In conclusion, our findings suggest that the antibacterial mode of action of β-amyrin involves the induction of ROS, which resulted in apoptosis-like death in E. coli.

• Nuclear Engineering and Technology
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• 제54권11호
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• pp.4049-4061
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• 2022

TRISO-coated particle fuel is widely used in high temperature gas cooled reactors and other advanced reactors. The performance of coated fuel particle is one of the fundamental bases of reactor safety. The failure probability of coated fuel particle should be evaluated and determined through suitable fuel performance models and methods during normal and accident condition. In order to better facilitate the design of coated particle fuel, a new TRISO fuel performance code named FRAT (Fission product Release Analysis Tool) was developed. FRAT is designed to calculate internal gas pressure, mechanical stress and failure probability of a coated fuel particle. In this paper, FRAT was introduced and benchmarked against IAEA CRP-6 benchmark cases for coated particle failure analysis. FRAT's results agree well with benchmark values, showing the correctness and satisfactory applicability. This work helps to provide a foundation for the credible application of FRAT.

• Journal of Sport and Applied Science
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• 제8권2호
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• pp.19-23
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• 2024

Purpose: This study sought to explore theoretical knowledge of benefits that sport participants perceived. In specific, this study reviewed related literature to explore similarities and differences of perceived benefits between competitive sport and eco-sport. Research design, data, and methodology: This study employed an integrated literature review approach. A conceptual model is suggested by reviewing prior studies. The study collected relevant documents via online search engine including KCI and google scholar. The contents and results of collected data were analyzed and categorized into perceived benefits between competitive sport and eco-sport. Results: For results, summary of perceived benefits was presented. In specific, a total of twelve variables were derived from the literature analysis as physical benefits of sport participation, which include cardiorespiratory fitness and physical self-concept and so forth. Second, a total of six mental benefits were discovered by prior studies, including happiness, stress release, psychological health and so on. Third, in terms of socio-relational benefits, four variables were derived from previous literature, which are social support, trust, and social capital and so on. Conclusions: This study identified positive outcomes of physical activities. Furthermore, a variety of benefits were categorized into three major aspects such as physical, mental, and social benefits. The study needs to be conducted to explore the effects of perceived benefits on repeat participation. Further implications were discussed.

• IMMUNE NETWORK
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• 제21권5호
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• pp.36.1-36.16
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• 2021

Peroxiredoxins (Prxs) are ubiquitously expressed peroxidases that reduce hydrogen peroxide or alkyl peroxide production in cells. Prxs are released from cells in response to various stress conditions, and they function as damage-associated molecular pattern molecules. However, the secretory mechanism of Prxs and their roles have not been elucidated. Thus, we aimed to determine whether inflammasome activation is a secretory mechanism of Prxs and subsequently identify the effect of the secreted Prxs on activation of the classical complement pathway. Using J774A.1, a murine macrophage cell line, we demonstrated that NLRP3 inflammasome activation induces Prx1, Prx2, Prx5, and Prx6 secretion in a caspase-1 dependent manner. Using HEK293T cells with a transfection system, we revealed that the release of Prx1 and Prx2 relies on gasdermin-D (GSDMD)-mediated secretion. Next, we confirmed the binding of both Prx1 and Prx2 to C1q; however, only Prx2 could induce the C1q-mediated classical complement pathway activation. Collectively, our results suggest that inflammasome activation is a secretory mechanism of Prxs and that GSDMD is a mediator of their secretion. Moreover, secreted Prx1 and Prx2 bind with C1q, but only Prx2 mediates the classical complement pathway activation.

• Natural Product Sciences
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• 제13권1호
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• pp.1-5
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• 2007

Dietary flavonoids have antioxidant and antitumor promoting effects. Rhus verniciflua Stokes (RVS) is a flavonoid-rich herbal medicine and has long been used as a food additive and an antitumor agent in Korea. Previous study demonstrated that a purified flavonoid fraction prepared from RVS, herein named RCMF (the RVS chloroform-methanol fraction), exhibited growth inhibition and induced apoptosis in human osteosarcoma(HOS) cells. This study evaluated if p53-mediated pathway is associated with the RCMF-induced apoptosis in HOS cells. RCMF was shown to be capable of inducing apoptosis of the cells, as expected, and transparently increased p53 expression in the cells. However, the RCMF-induced cytotoxicity was suppressed by transfecting the cells with antisense p53 oligonucleotide, which also inhibited the decrease of Bcl-2 and the increase of Bax in mitochondria, and the release of cytochrome c into cytosol. This finding suggests that p53-mediated mitochondrial stress is required for RCMF-induced apoptosis in HOS cells.

• Asian-Australasian Journal of Animal Sciences
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• 제17권11호
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• pp.1599-1607
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• 2004

This study examined the effects of pre-slaughter fasting, chasing stress and chiller ageing on objective meat quality, and their relations to the proteome profile of longissimus muscle using 20 male Korean native black pigs. Treatments were composed of two levels of pre-slaughter feed withdrawal, two levels of pre-slaughter stress and four chiller ageing times. A 15 min chasing stress immediately prior to slaughter significantly (p<0.05) decreased detectable levels of $\mu$-calpain activity during rigor development and chiller ageing, but did not have any direct effect on objective meat quality. On the other hand, pigs fed until the morning of slaughter resulted in significantly (p<0.05) higher hunter L* value and cooking loss than those which received an 18 h feed withdrawal prior to slaughter. Cooking loss and hunter L* value were constant during 7 d of chiller ageing, followed by significant increases at 14 d. The fed animals showed a significantly (p<0.05) higher hunter a* value at both 3 and 7 d, while the other group maintained a stable redness for 7 d. WB-shear force was not affected by the pre-slaughter treatments, but had significant (p<0.05) linear reduction from 1 to 7 d. A gelbased proteome analysis was performed on selected animals for low and high hunter L* values at 1 d. Ten and five spots had greater than two-fold spot densities for the low and high hunter L* groups, respectively. The ten spots included chain A, deoxyribounclease I complex with actin, heat shock protein 27 kDa, a protein similar to cardiac $Ca^{2+}$ release channel, and myosin heavy chain, while the five spots included chain A aldehyde dehydrogenase, glycerol-3 phosphate dehydrogenase, and hemoglobin alpha chain. In general, feeding until the morning of slaughter resulted in more desirable meat color, but appeared to reduce palatability due to increased cooking loss. Proteome analysis demonstrated that various proteins were concomitantly involved in the determination of final meat color. The most noticeable observation in the current study was that various isoforms for a particular protein differed in degradation and/or expression rate depending on meat quality.

• 한국자원식물학회지
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• 제25권2호
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• pp.184-192
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• 2012

본 연구는 췌장베타세포인 HIT-T15 세포를 이용하여 매실주정추출물(PME)의 alloxan에 의한 산화스트레스로부터의 세포보호, 인슐린 분비능 및 항산화 효소 활성을 평가하였다. PME는 alloxan에 의해 유발된 산화스트레스로부터 세포를 보호하여 세포생존율을 증가시켰다. PME는 세포막 손상지표인 LDH 방출을 억제하였고 $NAD^+$/NADH ratio를 유의적으로 증가시켜 세포사멸이 억제되어짐을 확인하였다. 또한 alloxan 단독처리군에 비해 250 ${\mu}g$/ml PME 처리군에서 인슐린 분비량이 유의성 있게 증가하였다. Alloxan과 PME를 동시에 처리하여 HIT-T15세포의 항산화효소 활성을 측정했을 때 산화스트레스에 의해 감소되었던 항산화효소 활성이 PME에 의해 보호되는 효과를 확인하였다. 이상의 연구결과로부터 PME는 세포괴사 및 DNA fragmentation을 억제하고 세포내 항산화효소 활성을 증가시켜 alloxan에 의해 유발된 산화스트레스로부터 췌장베타세포를 보호하고 이에 따른 인슐린 분비능 조절 효과가 있는 것으로 생각된다.

• 농업생명과학연구
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• 제44권2호
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• pp.57-66
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• 2010

자색고구마 추출물의 항산화 효과와 산화적 스트레스로 유도된 PC12 신경세포에 대한 보호효과에 대하여 연구하였다. 자색고구마 추출물의 총 페놀함량은 44.25 mg/g, monomeric anthocyanin 함량은 2,394 mg/L로 나타났다. 자색고구마 추출물의 1,1-diphenyl-2-picrylhydrazyl (DPPH), 2,2'-azino-bis-(3-ethylben-zthiazoline-6-sulfonic acid) (ABTS) radical 소거활성, ferric reducing/antioxidant power (FRAP) 및 환원력은 농도 의존적으로 항산화 활성이 증가하였다. MTT {3-(4,5-dimethylthiazol-2-yl)- 2,5-diphenyl-tetrazoliumbromide} reduction assay를 이용하여 자색고구마 추출물의 신경세포 보호효과를 측정한 결과, 세포 생존율이 두드러지게 증가하는 것으로 나타났다. 산화적 스트레스는 신경세포막 손상 정도를 증가시키기 때문에 lactate dehydrogenase (LDH) release assay와 neutral red uptake assay를 이용하여 세포막 손상 보호효과를 조사한 결과 자색고구마 추출물 처리구는 대조구에 비하여 산화적 스트레스로 유도된 세포막 손상 보호효과가 농도 의존적으로 나타났다. 따라서 자색고구마 추출물은 천연 항산화 소재 및 알츠하이머성 치매와 같은 신경퇴행성 질환의 예방 소재로서의 활용 가능성이 기대된다.