• Asian Pacific Journal of Cancer Prevention
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• 제14권6호
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• pp.3773-3778
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• 2013

Increased oxidative stress and changes in DNA methylation are frequently detected in bladder cancer patients. We previously demonstrated a relationship between increased oxidative stress and hypomethylation of the transposable long-interspersed nuclear element-1 (LINE-1). Promoter hypermethylation of a tumor suppressor gene, runt-related transcription factor 3 (RUNX3), may also be associated with bladder cancer genesis. In this study, we investigated changes of DNA methylation in LINE-1 and RUNX3 promoter in a bladder cancer cell (UM-UC-3) under oxidative stress conditions, stimulated by challenge with $H_2O_2$ for 72 h. Cells were pretreated with an antioxidant, tocopheryl acetate for 1 h to attenuate oxidative stress. Methylation levels of LINE-1 and RUNX3 promoter were measured by combined bisulfite restriction analysis PCR and methylation-specific PCR, respectively. Levels of LINE-1 methylation were significantly decreased in $H_2O_2$-treated cells, and reestablished after pretreated with tocopheryl acetate. Methylation of RUNX3 promoter was significantly increased in cells exposed to $H_2O_2$. In tocopheryl acetate pretreated cells, it was markedly decreased. In conclusion, hypomethylation of LINE-1 and hypermethylation of RUNX3 promoter in bladder cancer cell line was experimentally induced by reactive oxygen species (ROS). The present findings support the hypothesis that oxidative stress promotes urothelial cell carcinogenesis through modulation of DNA methylation. Our data also imply that mechanistic pathways of ROS-induced alteration of DNA methylation in a repetitive DNA element and a gene promoter might differ.

• Smart Structures and Systems
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• 제15권1호
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• pp.135-150
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• 2015

Large concrete structures are prone to cracks and damages over time from human usage, weathers, and other environmental attacks such as flood, earthquakes, and hurricanes. The health of the concrete structures should be monitored regularly to ensure safety. A reliable method of real time communications can facilitate more frequent structural health monitoring (SHM) updates from hard to reach positions, enabling crack detections of embedded concrete structures as they occur to avoid catastrophic failures. By implementing an unconventional mode of communication that utilizes guided stress waves traveling along the concrete structure itself, we may be able to free structural health monitoring from costly (re-)installation of communication wires. In stress-wave communications, piezoelectric transducers can act as actuators and sensors to send and receive modulated signals carrying concrete status information. The new generation of lead zirconate titanate (PZT) based smart aggregates cause multipath propagation in the homogeneous concrete channel, which presents both an opportunity and a challenge for multiple sensors communication. We propose a time reversal based pulse position modulation (TR-PPM) communication for stress wave communication within the concrete structure to combat multipath channel dispersion. Experimental results demonstrate successful transmission and recovery of TR-PPM using stress waves. Compared with PPM, we can achieve higher data rate and longer link distance via TR-PPM. Furthermore, TR-PPM remains effective under low signal-to-noise (SNR) ratio. This work also lays the foundation for implementing multiple-input multiple-output (MIMO) stress wave communication networks in concrete channels.

• Geomechanics and Engineering
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• 제24권6호
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• pp.519-529
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• 2021

In coal mining activities, the abutment stress of the coal has to undergo cyclic loading and unloading, affecting the strength and seepage characteristics of coal; additionally, it can cause dynamic disasters, posing a major challenge for the safety of coal mine production. To improve the understanding of the dynamic disaster mechanism of gas outburst and rock burst coupling, triaxial devices are applied to axial pressure cyclic loading-unloading tests under different axial stress peaks and different pore pressures. The existing empirical formula is use to perform a non-linear regression fitting on the relationship between stress and permeability, and the damage rate of permeability is introduced to analyze the change in permeability. The results show that the permeability curve obtained had "memory", and the peak stress was lower than the conventional loading path. The permeability curve and the volume strain curve show a clear symmetrical relationship, being the former in the form of a negative power function. Owing to the influence of irreversible deformation, the permeability difference and the damage of permeability mainly occur in the initial stage of loading-unloading, and both decrease as the number of cycles of loading-unloading increase. At the end of the first cycle and the second cycle, the permeability decreased in the range of 5.777 - 8.421 % and 4.311-8.713 %, respectively. The permeability decreases with an increase in the axial stress peak, and the damage rate shows the opposite trend. Under the same conditions, the permeability of methane is always lower than that of helium, and it shows a V-shape change trend with increasing methane pressures, and the permeability of the specimen was 3 MPa > 1 MPa > 2 MPa.

• 생명과학회지
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• 제33권7호
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• pp.586-592
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• 2023

돼지 정액을 저장하는 동안 산화스트레스의 발생은 정자의 질과 생존에 영향을 미치는 중요한 인자이다. 정액의 저장은 온도 변화, 동결보호제 등의 다양한 스트레스 인자에 노출되어 있다. 이러한 정자 내에서의 산화스트레스는 활성산소종의 생성에 의해 발생되며, 이는 지질, 단백질, DNA와 같은 세포를 구성하는 물질에 산화적으로 손상을 일으킨다. 활성산소종과 항산화물질의 균형있는 체계는 정자의 생존과 그 기능을 유지하는 데 중요한 역할을 한다. 정액을 장기간 보존하게 되면 활성산소종의 수준이 증가하여 정자의 운동성, 막 온전성, DNA 온전성에 영향을 미치게 된다. 또한, 활성산소종에 의해 유도된 지질과산화 반응은 정자막의 유동성과 안정성에 영향을 미쳐 정자의 운동성을 감소시킨다. 그리고, DNA의 산화적 손상은 DNA 단편화를 일으켜 정자의 DNA 온전성을 손상시킬 수 있다. 결론적으로, 정액을 보관하는 동안 발생되는 산화스트레스는 정자의 질과 기능을 유지하는 데 중요하다. 따라서, 산화스트레스의 기본적인 메커니즘과 정자의 기능에 미치는 영향을 이해하는 것은 산화스트레스로부터의 손상을 최소화하고, 효율적이고 기능적인 정자의 저장 방법을 개선하기 위한 효과적인 전략과 연구 개발을 위해 중요할 것으로 판단된다.

• IMMUNE NETWORK
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• 제16권4호
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• pp.242-248
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• 2016

Thymic atrophy is a complication that results from exposure to many environmental stressors, disease treatments, and microbial challenges. Such acute stress-associated thymic loss can have a dramatic impact on the host's ability to replenish the necessary naïve T cell output to reconstitute the peripheral T cell numbers and repertoire to respond to new antigenic challenges. We have previously reported that treatment with the orexigenic hormone ghrelin results in an increase in the number and proliferation of thymocytes after dexamethasone challenge, suggesting a role for ghrelin in restraint stress-induced thymic involution and cell apoptosis and its potential use as a thymostimulatory agent. In an effort to understand how ghrelin suppresses thymic T cell apoptosis, we have examined the various signaling pathways induced by receptor-specific ghrelin stimulation using a restraint stress mouse model. In this model, stress-induced apoptosis in thymocytes was effectively blocked by ghrelin. Western blot analysis demonstrated that ghrelin prevents the cleavage of pro-apoptotic proteins such as Bim, Caspase-3, and PARP. In addition, ghrelin stimulation activates the Akt and Mitogen-activated protein kinases (MAPK) signaling pathways in a time/dose-dependent manner. Moreover, we also revealed the involvement of the FoxO3a pathway in the phosphorylation of Akt and ERK1/2. Together, these findings suggest that ghrelin inhibits apoptosis by modulating the stress-induced apoptotic signal pathway in the restraint-induced thymic apoptosis.

• Asian-Australasian Journal of Animal Sciences
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• 제27권7호
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• pp.1035-1043
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• 2014

To investigate the effect of dietary Acanthopanax senticosus polysaccharide (ASPS) on growth performance, immunity, blood parameters and mRNA expression of pro-inflammatory cytokines in immunologically challenged piglets, an experiment employing $2{\times}2$ factorial arrangement concerning dietary ASPS treatment (0 or 800 mg/kg) and immunological challenge (lipopolysaccharide [LPS] or saline injection) was conducted with 64 crossbred piglets (weaned at 28 d of age, average initial body weight of $7.25{\pm}0.21kg$) assigned to two dietary ASPS treatments with 8 replicates of 4 pigs each. Half of the piglets of per dietary treatment were injected with LPS or saline on d 14. Blood samples were obtained at 3 h after immunological injection on d 14 and piglets were slaughtered to obtain spleen samples on d 21. Dietary ASPS did not affect average daily gain (ADG) (p = 0.634), average daily feed intake (ADFI) (p = 0.655), and gain:feed (p = 0.814) prior to LPS challenge. After LPS challenge, for LPS-challenged pigs those fed ASPS had higher ADG and ADFI than the non-supplemented group (p<0.05), and an interaction between $LPS{\times}ASPS$ was observed on the two indices (p<0.05). Dietary ASPS improved lymphocyte proliferation among saline-injected and LPS-injected pigs (p<0.05). Interaction between $LPS{\times}ASPS$ was also revealed on lymphocyte proliferation (p<0.05). Circulatory concentration of IgG was influenced neither by ASPS (p = 0.803) or LPS (p = 0.692), nor their interaction (p = 0.289). Plasma concentration and spleen mRNA expression of interleukin-1beta (IL-$1{\beta}$), interleukin-6 (IL-6), and tumor necrosis factor (TNF)-${\alpha}$ were induced to increase (p<0.05) by LPS challenge, in contrast, these indices were decreased by dietary ASPS (p<0.05), and interactions were found on these cytokines (p<0.05). For LPS-challenged pigs, dietary ASPS also reduced the circulating concentration and spleen mRNA expression of IL-$1{\beta}$, IL-6 as well as TNF-${\alpha}$ (p<0.05). The interaction between $LPS{\times}ASPS$ was also observed on the circulating concentration of insulin-like growth factor-I, ${\alpha}$-acid glycoprotein (${\alpha}$-AGP), nonesterified fatty acid, and glucose (p<0.05). The results of this study demonstrate that dietary ASPS can modulate the release of pro-inflammatory cytokines during immunological challenge, which might enable piglets to achieve better growth performance.

• 한국전자통신학회논문지
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• 제16권6호
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• pp.1101-1112
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• 2021

정보가 조직의 핵심 관리 요인으로 인식되면서, 조직들은 정보 자산에 대한 침입 및 노출에 대처하기 위하여 정보보안 정책 및 기술에 대한 투자를 지속해서 증가하고 있다. 그러나, 엄격한 정보 관리를 위한 조직의 규정 및 행동 요구가 많아질수록, 실제 정보보안 정책을 업무에 적용하는 조직원에게는 스트레스를 일으켜 부정적 행동을 유발할 수 있다. 본 연구는 스트레스 조건이 긍정적, 부정적 행동 원인으로 작용하는 도전적, 방해적 스트레서가 정보보안 준수의도에 미치는 영향을 제시하고, 진성 리더십이 스트레서의 영향을 어떻게 조절하는지를 확인하는 것을 목적으로 한다. 연구 대상은 보안 정책을 업무에 적용하고 있는 조직 근로자로 하였으며, 서베이 기법을 적용하여 선행연구를 통해 도출한 측정 항목의 응답 결과를 확보하였다. 구조방정식모델링을 통해 검증한 결과, 도전적, 방해적 스트레서가 준수 의도에 영향을 주었으며, 진성 리더십이 스트레서의 영향을 조절하였다. 결과는 내부자의 보안 준수 수준에 영향을 주는 스트레서 조건과 리더의 행동 방향을 제시하였기 때문에, 내부자 정보보안 목표 달성을 위한 구성원 지원 전략 수립에 도움을 준다.

• Animal Bioscience
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• 제35권6호
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• pp.938-947
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• 2022

Objective: The beneficial effects of glycine were tested in piglets with diquat-induced hepatic injury. Methods: Thirty-two piglets were assigned by a 2×2 factorial experimental design including glycine supplementation and diquat challenge. After 3 weeks of feeding with a basic diet or a 1% glycine supplemented diet, piglets were challenged with diquat or saline. After 1 week later, the piglets were slaughtered and samples were collected. Results: Our results indicated that glycine alleviated diquat induced morphological hepatic injury, decreased the activities of plasma alanine aminotransferase, aspartate aminotransferase and glutamyl transpeptidase in the piglets under diquat challenge, and increased total antioxidant capacity and antioxidative enzyme activity significantly. Adding glycine enhanced the concentrations of hepatic adenosine triphosphate and adenosine diphosphate. Transmission electron microscope observation showed that diquat induced clear hepatocytes ferroptosis and its effect could be alleviated by glycine to a certain degree. Moreover, glycine significantly affected mRNA and protein expression of ferroptosis-related signals in the liver. Conclusion: These results demonstrated that glycine attenuated liver damage via inhibiting ferroptosis.

• 한국식물병리학회:학술대회논문집
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• 한국식물병리학회 2003년도 정기총회 및 추계학술발표회
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• pp.101.2-102
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• 2003

The ability of P. chlororaphis O6 to induce resistance to Erwinia carotovora subsp. carotovara SCCI and to promote growth in tobacco was demonstrated in microtiter assays on plants pre-inoculated at the root level with the bacteria before challenge with the leaf pathogen. To identify th bacterial determinants involved in induced systemic resistance and plant growth promotion, cell culture of O6 grown in King's medium B was fractionated with organic solvents and purified using various columns. in vivo and in vitro assays with samples from successive fractionation steps of the O6 supernatant led to the conclusion that antibacterial compounds were observed in aqueous layer, and to the isolation of fractions containing metabolites that retained most of the resistance-inducing activity (70：30, methanol：water) and the plant growth promotion (80：20 and 90：10, methanol：water) after ODS column chromatography. Although these molecules remain to be purified further and structurally characterized, its isolation is an addition to the range of determinants from plant growth-promoting rhizobacteria known to stimulate plant defence.

• Geomechanics and Engineering
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• 제15권6호
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• pp.1153-1160
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• 2018

Rockbursts, catastrophic events involving the violent release of elastic energy stored in rock features, remain a worldwide challenge for geoengineering. Especially at deep-mining sites, rockbursts can occur in hard, high-stress, brittle rock zones, and the associated risk depends on such factors as mining activity and the stress on surrounding rocks. Rockbursts are often sudden and destructive, but there is still no unified standard for predicting them. Based on previous studies, a new Bayesian multi-index model was introduced to predict and evaluate rockbursts. In this method, the rock strength index, energy release index, and surrounding rock stress are the basic factors. Values from 18 rock samples were obtained, and the potential rockburst risks were evaluated. The rockburst tendencies of the samples were modelled using three existing methods. The results were compared with those obtained by the new Bayesian model, which was observed to predict rockbursts more effectively than the current methods.