• Title/Summary/Keyword: 열 스트레스 반응

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Effects of Trampling on Growth and Development in Zoysia japonica (답압이 한국잔디의 생육에 미치는 영향)

  • Seo, Jin Yeol;Chung, Jong Il;Kim, Min Chul;Chung, Jung Sung;Shim, Doo Bo;Song, Seon Hwa;Oh, Ji Hyun;Shim, Sang In
    • Weed & Turfgrass Science
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    • v.4 no.3
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    • pp.256-261
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    • 2015
  • Trampling stress in turfgrass fields caused by traffics often occurs in zoysiagrass (Zoysia japonica) fields including golf course. In order to know the influences of trampling stress on the growth and development of turfgrass, leaf and root growth, chlorophyll fluorescence, chlorophyll content and 2-DE protein analysis were conducted in the turfgrass plants subjected to various levels of trampling stress from 0 to $9,420J\;day^{-1}$ day. Shoot growth was more highly inhibited by trampling stress than root growth. Although root growth was affected by trampling with weak intensity, the highest root length was observed in the turfgrass treated with weak trampling ($1,570J\;day^{-1}$). Chlorophyll fluorescence (Fv $Fm^{-1}$) was drastically lowered by trampling stress with moderate intensity. Leaf number showed similar tendency with leaf greenness. The number was decreased as the trampling intensity was increased. Shoot dry weight was decreased showing a similar tendency with the result of shoot length. The specific protein expressions under weak trampling were related to the functions of stress amelioration. Heat shock 70 kDa protein 10 and oxygen-evolving enhancer protein 1 were the proteins increased positively under trampling stress.

Application of Plant Flavonoids as Natural Antioxidants in Poultry Production (가금 생산에서 천연 항산화제로서 식물성 Flavonoids의적용)

  • Kang-Min, Seomoon;In-Surk, Jang
    • Korean Journal of Poultry Science
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    • v.49 no.4
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    • pp.211-220
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    • 2022
  • Poultry are exposed to extremely high levels of oxidative stress as a consequence of the excessive production of reactive oxygen species (ROS) induced by endogenous and exogenous stressors, such as high-stocking densities, thermal stress, environmental and feed contamination, along with factors associated with intensive breeding systems. Oxidative stress promotes lipid peroxidation, DNA damage, and inflammation, which can have detrimental effects on the health of birds. During the course of evolution, birds have developed antioxidant defense mechanisms that contribute to maintaining homeostasis when exposed to endogenous and exogenous stressors. The primary antioxidant defense systems are enzymatic and non-enzymatic in nature and play roles in protecting cells from ROS attack. Recently, plant flavonoids, which have been established to reduce oxidative stress, have been attracting considerable attention as potential feed additives. Flavonoids are a group of polyphenolic compounds that can be stabilized by binding structural compounds with ROS, and can promote the elimination of ROS by inducing the expression of antioxidant enzymes. However, although flavonoids can contribute to reducing lipid peroxidation and thereby enhance the antioxidant capacity of birds, they have low solubility in the gastrointestinal tract, and consequently, it is necessary to develop a delivery technology that can facilitate the effect intestinal absorption of these compounds. Furthermore, it is important to determine the dietary levels of flavonoids by assessing the exact antioxidant effects in the gastrointestinal tract wherein the concentrations of dietary flavonoids are highest. It is also necessary to examine the expression of transcriptional factors and vitagenes associated with the efficient antioxidant effects induced by flavonoids. It is anticipated that the application of flavonoids as natural antioxidants will become a particularly important field in the poultry industry.

The Electrical Characteristics of Low-Temperature Poly-Si Thin-Film Transistors by Different Crystallization Methods

  • Kim, Mun-Su;Jang, Gyeong-Su;Lee, Jun-Sin
    • Proceedings of the Korean Vacuum Society Conference
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    • 2014.02a
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    • pp.287.1-287.1
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    • 2014
  • 본 연구에서는 현재 디스플레이에서 가장 널리 이용되는 저온 polycrystalline silicon (poly-Si)의 결정화 방법에 따른 thin-film transistor (TFT)의 전기적 특성을 분석하였다. 분석에 이용된 결정화 방식은 Excimer Laser Annealing (ELA)와 Metal Induced Crystallization (MIC)이다. ELA와 MIC TFTs의 전기적 특성 측정을 통한 분석결과 ELA와 MIC poly-Si TFTs의 전기적 특성 [field-effect mobility (${\mu}_{FE}$), on/off current ratio ($I_{ON}/I_{OFF}$), sub-threshold swing (SS)]은 큰 차이는 없지만, ELA를 이용한 poly-Si TFT의 전기적 특성이 조금 우수하다. 하지만, MIC poly-Si TFT의 경우 threshold voltage ($V_{TH}$)가 0V에 보다 가까울 뿐만 아니라, 전기적 스트레스를 통한 신뢰성 확인 시 ELA poly-Si TFT보다 조금 더 안정적이다. 이는 ELA의 경우 좁은 면에 선형 레이저 빔으로 조사하면서 생기는 hill-lock의 영향으로 표면이 거칠고 균일하지 못하여 바이어스 인가시 생기는 문제이다. 또한 MIC는 금속 촉매를 이용해 결정립 경계를 확장하고 결정 크기를 키워 대면적화에 유리하다. Thermal Stress에서는 (from 293K to 373K) TFT에 점차 높은 온도를 가하자 MIC poly-Si TFT의 경우 off 상태에서 누설 전류 값이 증가하며 열에 민감한 반응을 보이는 것을 확인하였다.

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A decision-centric assessment of flood risk and supply reliability at a multi-purpose reservoir under climate change (의사결정중심 다목적댐 이치수 안전도 기후변화 영향평가)

  • Kim, Daeha;Kim, Eunhee;Lee, Seung Cheol;Kim, Eunji
    • Proceedings of the Korea Water Resources Association Conference
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    • 2022.05a
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    • pp.112-112
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    • 2022
  • 본 연구에서는 2005-2020년 용담댐의 운영방식이 기후변화에 얼마나 취약한 지 홍수위험과 이수 안전도 지표를 중심으로 평가하였다. 유입량 모의를 위해 GR6J 강우-유출 모형을 사용했고, 댐 운영룰 추출을 위해 Random Forests 모형을 관측자료에 적합시켰다. 294개의 추계학적 기후스트레스 시계열을 GR6J 모형에 입력해 일유입량을 모의한 후 Random Forests 모형으로 방류량과 저수량을 추정하여 연최대일방류량과 공급신뢰도를 분석하였다. 공급신뢰도는 평균강수량 변화에 주로 영향을 받는 것으로 나타났지만 연최대방류량은 평균강수량과 강수변동성 변화에 모두 민감하게 반응하는 것을 알 수 있었다. 2021-2040년 용담댐 저수량은 평균강수량 증가로 인해 공급신뢰도는 과도하게 상승할 것으로 전망되었다. 하지만 강수변동성 증가 인해 20년 빈도 연최대방류량은 가파르게 상승해 댐 하류지역의 홍수위험은 더 가중될 것으로 전망되었다.

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Properties of $SiO_2$Deposited by Remote Plasma Chemical Vapor Deposition(RPCVD) (원거리 플라즈마 화학증착법으로 증착된 이산화규소박막의 물성)

  • Park, Yeong-Bae;Gang, Jin-Gyu;Lee, Si-U
    • Korean Journal of Materials Research
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    • v.5 no.6
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    • pp.706-714
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    • 1995
  • Silicon oxide thin films were deposited by remote plasma chemical vapor deposition (RPCYD). The effect of the operating variables, such as plasma power, deposition temperature and partial pressure of reactant on the material Properties of the silicon oxide film was investigated. By XPS, it was found out that the film was suboxide (O/Si<2) and small amount of nitrogen due to the plasma excitation was accumulated at the Si/SiO$_2$interface. The amount of dangling bonds at the Si/SiO$_2$interfaces were measured by ESR and the concentration of hydrogen bond was obtained by SIMS and FT-IR. The bond angle distribution(d$\theta$/$\theta$) was shown to be similiar to thermal oxide above 20$0^{\circ}C$ but the etch rate was higher than that of the thermal oxides due to the structural difference and the stress between silicon substrate and silicon oxide film.

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Analysis of Gene Expression in Larval Fat Body of Plutella Xylostella Under High Temperature (고온에서 배추좀나방 유충 지방체의 유전자 발현 변화 분석)

  • Kim, Kwang Ho;Lee, Dae-Weon
    • Korean Journal of Environmental Agriculture
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    • v.37 no.4
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    • pp.324-332
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    • 2018
  • BACKGROUND: Insects are ectothermic organisms in terrestrial ecosystems and play various roles such as controlling plant biomass and maintaining species diversity. Because insects are ectothermic, their physiological responses are very sensitive to environmental temperature which determines survival and distribution of insect population and that affects climate change. This study aimed to identification of genes contributing to fitness under high temperature. METHODS AND RESULTS: To identify genes contributing to fitness under high temperature, the transcriptomes of fat body in Plutella xyostella larva have been analyzed via next generation sequencing. From the fat body transcriptomes, structure-related proteins, heat shock proteins, antioxidant enzymes and detoxification proteins were identified. Genes encoding proteins such as structural proteins (cuticular proteins, chitin synthase and actin), stress-related protein (cytochrome P450), heat shock protein and antioxidant enzyme (catalase) were up-regulated at high temperature. In contrast expression of glutathione S transferase was down-regulated. CONCLUSION: Identifications of temperature-specific up- or down-regulated genes can be useful for detecting temperature adaptation and understanding physiological responses in insect pests.

Thermal Comfort and the Physiological and Psychological Effects of Spending Time in Broad-Leaved Forests in Summers (여름철 활엽수림에서의 휴식이 온열환경 쾌적성 및 인체의 생리ᐧ심리적 반응에 미치는 영향)

  • Juhyeon Kim;Injoon Song;Choyun Kim;Dawou Joung;Yunjeong Yi;Bum-Jin Park;Chorong Song
    • Journal of Korean Society of Forest Science
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    • v.112 no.4
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    • pp.544-553
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    • 2023
  • The purpose of this study was to reveal the thermal comfort and physiological and psychological effects of spending time in broad-leaved forests in suumer. Thirty-one university students (with an average age of 21.4 ± 2.1 years) participated in the study, and a within-subjects experimental design methodology was used. The participants moved to an experimental site (with a crown closure of 76.6%) or a control site (25.9%), sat on a chair to eliminate the impact of movement, and rested for 5 minutes with closed eyes. At this time, thermal comfort, heart rate variability, heart rate, and forehead temperature were continuously measured. After that, blood pressure and pulse rate were measured, and a subjective evaluation was conducted. As a result, spending time at an experimental site showed a statistically significant decrease in the predicted mean vote and the percentage of dissatisfied values, enhancement of parasympathetic nerve activity, decrease of forehead temperature, diastolic blood pressure, heart rate, pulse rate, and improvement of personal thermal sensation (thermal sensation vote and comfort sensation vote). In conclusion, it was found that a forest with high crown closure reduces thermal stress and induces physiological and psychological relaxation.

Bioaccumulation and Expressions of Stress Response Genes in Benthic Oligochaete Worm Tubifex tubifex to Exposure of Cadmium-spiked Sediment (카드뮴 (Cd) 노출 퇴적물에 따른 실지렁이 Tubifex tubifex의 체내 축적과 스트레스 반응 유전자 발현)

  • Ji-Hoon Kim;Won-Seok Kim;Kiyun Park;Ihn-Sil Kwak
    • Korean Journal of Ecology and Environment
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    • v.56 no.4
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    • pp.320-329
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    • 2023
  • Cadmium (Cd), a heavy metal found in the aquatic environment, accumulates in organisms through the food chain. In the study, we investigated the survival rates, measurement of body Cd levels, and expression analysis of the stress response genes (Heat shock protein 70: HSP70 and Heat shock protein 60: HSP60) and antioxidant enzyme Glutathione S-Transferases (GST) on benthic oligochaete worm Tubifex tubifex exposed three concentrations of Cd, to analyze the bioaccumulation and changes of stress gene expressions to exposure toxicity of the Cd-spiked sediment. Survival rates of T. tubifex exposed to the Cdspiked sediment were 93% at 0.4 mg kg-1 Cd, 96% at 1.87 mg kg-1 Cd, and 93% at 6.09 mg kg-1 Cd for 10 days. Cd concentration in the body of T. tubifex was higher than that in the sediment. After Cd exposures for 10 days, the body Cd levels were 18.4 mg kg-1, 13.06 mg kg-1, and 79.11 mg kg-1 at exposed three concentrations of Cd, respectively. Upregulation of HSP70 gene expression was observed at all concentrations of exposed Cd as a time-dependent manner, whereas transcriptional expression of the HSP60 gene increased as a timedependent manner in T. tubifex exposed to the relative high concentration (6.09 mg kg-1) of Cd. However, GST gene expression increased on day 1 at all concentrations after Cd exposures, and then downregulated until 10 days. These results indicate to ecotoxicological and molecular effects in benthic oligochaete worm T. tubifex to Cd-spiked sediment and provide the basic information for the utilization of environmental toxicity assessment using the T. tubifex as a aquatic pollution indicator species.

A Study on Psychological Factors and Gastric Physiological Activity in the Functional Dyspepsia -Using Gastric Emptying Test- (가능성 소화장애증 환자의 정신사회적 요인과 위장 생리활동성의 연관성에 관한 연구 -위 배출능 검사를 이용하여-)

  • Kim, Jin-A;Lim, Seung-Han;Moon, Seong-Keun;Lee, Sang-Yeol
    • Korean Journal of Psychosomatic Medicine
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    • v.9 no.1
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    • pp.49-57
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    • 2001
  • Objectives : This study was designed to investigate the relationship between gastric emptying, psychopathology(especially anxiety and depression), and various factors that can mediate stress and response, such as coping style, social support and level of perceived stress. Methods : A total 30 patients who complained of the non-ulcer dyspepsia and did not have any abnormal finding on the gastroduodenal endoscopic examination, 24 hour ambulatory esophageal manometry and conventional gastroesophageal manometry were tested with gastric emptying that would be a functional examination of stomach. The correlations between the gastric emptying and psychological vaiable such as quantity of perceived stress, Symptom Checklist-90-Revision(SCL-90-R), Beck Depression Inventory(BDI), Spielberger Stait-Trait Anxiety Inventory(STAI), Ways of Coping Checklist and Interpersonal Support Evaluation List were evaluated. Results : 1) The mean and standard deviation of the time for half of the meal to empty(T50%) was $118.50{\pm}23.64$ minute which showed no gastric stasis in terms of gastric emptying test. 2) There were significant positive correlations between T50% and the state anxiety, T50% and thedepression. 3) There was no significant correlation between T50% and the quantity of perceived stress, T50% and mediating factors(coping style and social support). Conclusion : These results suggested that psychopathology, especially emotional components such as depression and anxiety, could affect on the current physiological functional gastric activity(gastric emptying), but quantity of perceive stress and mediating factors of stress and response such as coping style and social support could not affected on the functional gastric activity. These results showed that psychological interventions should considered in management of the patients with functional dyspepia.

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Life Time Prediction and Physical Properties of Chloroprene Rubber Aged by Seawater (클로로프렌 고무의 해수에 의한 물성 변화 및 노화 수명 예측)

  • Lee, Chan Koo;Yun, Ju Ho;Kim, Il;Shim, Sang Eun
    • Elastomers and Composites
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    • v.47 no.1
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    • pp.9-17
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    • 2012
  • Herein, life time prediction based on the deterioration of physical properties of chloroprene rubber (CR)aged by heat and seawater was performed. CR samples were experienced an accelerated test at $80^{\circ}C$, $100^{\circ}C$, $120^{\circ}C$ for heat aging, and $40^{\circ}C$, $60^{\circ}C$, $80^{\circ}C$ for seawater aging for 20,000 hrs. The change in tensile strength, maximum elongation,hardness was measured. As a result, the decrease in elongation was a major factor causing failure. The life time estimated using an Arrhenius model was 125 years at $23^{\circ}C$ for thermal aging and 9 years at $23^{\circ}C$ for seawater aging. SEM and elemental analysis reveal that cracks were generated and the content of oxygen was increased for CR agined by seawater. FT-IR spectrum shows the new C-O and C = O bonds were generated by the chemical reaction with seawater. Also, the glass transtion temperature was increased and the thermal decomposition was decreased by seawater aging.