• 제목/요약/키워드: Sources of stress

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수분 및 Salt Stress조건하에서 대맥품종의 발아력과 출현력의 차이 (Barley Varietal Differences in Germination and Emergence Capacity under Different Water and Salt Stress Conditions)

  • 천종은;이은섭;정동희;정태영
    • 한국작물학회지
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    • 제28권1호
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    • pp.122-127
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    • 1983
  • 본 시험은 수분 및 Salt stress 조건에서 우리나라 대맥 주요육성 품종 및 계통들의 발아력과 출현력의 품종간 차이를 구명하고자 Sucrose와 KC1 용액을 사용하여 실시하였던 바 그 결과를 요약하면 다음과 같다. 1. 수분 Stress에서 발아력의 품종간 변이는 -10 - -15bars에서 매우 컸으며 부흥, 밀양 006, 부호 보리 등이 양호하였다. 2. Salt stress에서 출현력의 품종간 변이는 약 -9bars에서 매우 컸으며 SB77415 - B -37, 조강보리, 동보리 001 등이 양호하였으며 초엽장, 유묘장과 정의 상관이 인정되었다. 3. 수분 Potential이 낮아짐에 따라 종자의 발아, 출현시기가 지연될 뿐 아니라 비율도 낮아져 초기입모가 불량하였다. 4. 수분 Stress에서 발아력과 Salt stress에서 출현력의 관계는 높은 정의 상관이 인정되었으며, 본 시험결과는 두 방법의 병용가능성과 품종간 차이를 구명하기 위해선 낮은 Potential(-9 bars)에서 실시해야 함을 제시해준다.

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산화적 스트레스에 대한 췌장 베타 세포 보호활성 식물추출물 탐색 (Search for Plant Extracts with Protective Effects of Pancreatic Beta Cell against Oxidative Stress)

  • 이동성;정길생;안인파;리빈;변에리사;김윤철
    • 생약학회지
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    • 제39권4호
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    • pp.335-340
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    • 2008
  • Diabetes mellitus is metabolic disorder characterized by hyperglycemia caused by insufficient insulin secretion or insulin receptor insensitivity to endogenous insulin. It is well-known that hyperglycemia is one of the main causes of oxidative stress in both type 1 and 2 diabetes. Oxidative stress is related by death of pancreatic ${\beta}$ cell and dysfunction of ${\beta}$ cell. Although ${\beta}$ cell death or dysfunction is induced by many substances or molecules, increased evidences that oxidative stress plays a crucial role in ${\beta}$ cell death or dysfunction. Considering the importance of oxidative stress in the pathogenesis of diabetes mellitus, we investigated the cytoprotective effects against hydrogen peroxide-induced oxidative stress in pancreatic ${\beta}$ cell line RIN-m5F cell. 110 Plant sources were collected in Mt. Baek-du, and extracted with methanol. These extracts had been screened the protective effects against hydrogen peroxide-induced oxidative damage in RIN-m5F cells at 50 and 200 ${\mu}g$/ml. Of these, ten methanolic extracts, aerial part of Erigenron cannadensis, aerial part of Lespedeza juncea, whole plant of Alopecurus aequalis, fruit of Lycium chinense, leaf of Morus alba, rhizome of Polygonatum odoratum, root of Ampelosis japonica, whole plant of Ranunculus japonicus, aerial part of Polygonum sieboldii, rhizome of Arisaema amurense var. violaceum showed significant protective effects against hydrogen peroxide-induced oxidative damage in pancreatic ${\beta}$ cell line RIN-m5F cell.

소셜 네트워크 서비스에서 사용자의 플로우와 스트레스가 주관적 안녕감에 미치는 영향 (The Effect of Individual's Flow and Stress on Subjective Well-being in Social Network Services)

  • 고준;이성준;누립국
    • 한국IT서비스학회지
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    • 제15권1호
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    • pp.211-226
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    • 2016
  • Most of the SNS users argue that they feel techno-stress or digital fatigue when they use SNS. As the relationships in the SNS expand, users may feel work overload, digital fatigue, and techno-stress which are caused by the time and effort for the retaining the existing relationships established via SNS. The SNS activities require users' time and effort to update their profiles and the current news of them, responding to online friends' contents. Thus, more relationships they have, more stress they can feel. This study tries to examine the key factors that can affect subjective well-being of individuals in Social Network Service (SNS) usage. Therefore, this study, based on the previous literature, investigates what the sources of SNS stress are and how SNS stress and flow affect subjective well-being of SNS users. Major findings of this study from an empirical analysis with 201 SNS user respondents who have accessed SNS at least one time within one month are as follows. First, perceived opportunity cost and reputation recognition in SNS usage were found to have significant effects on negative emotion. Second, individual's flow in SNS was significantly affected by challenges and interactions, and had a significant impact on positive emotion. However, SNS users' flow did not show a positive relationship with their satisfaction of life. This study contributes to the expansion of theoretical discussion about the effect of individual's SNS usage on quality of life in validating whether SNS usage can bring individuals subjective well-being. Implications of the study findings and future research directions are also discussed.

치기공과 학생들의 스트레스 요인분석에 관한 연구 - 대구.제주 중심으로 - (A study on the related factors of students' stress in dental laboratory college - focusing in Daegu and Jeju -)

  • 김정숙;정효경;박남규
    • 대한치과기공학회지
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    • 제30권1호
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    • pp.121-130
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    • 2008
  • The purpose of this research project is to assess students' stress during clinical rotations and to suggest strategies for enhancing professional skills as well as the quality of clinical rotations among the students of dental technology. The participants included 200 sophomores and juniors from dental laboratory college located in Daegu and Jeju. Data was collected December 7, 2007, and March 7, 2008, by survey samplings. A total of 185 completed surveys were obtained and analyzed for this study. Findings from the study are summarized below. When age and stress were compared, it was found that younger students had higher levels of stress related to their environment, role, and activities. Regarding grade level and stress, students in lower levels were slightly (p<.01) more likely to have stress (Sophomore =2.91, junior =2.49). When the stress level was compared with students' satisfaction with their major, the less students were satisfied, the higher their level of stress was. The study found a slight (p<.05) difference between groups [satisfaction group (M=2.44), group in between satisfaction and dissatisfaction (M=2.58), and dissatisfaction (M=2.82)) in the relationship between satisfaction with the major and overall stress. Again, it appears that stress levels increase as satisfaction with the chosen major decreases. Third, the intensity of stress was affected by the environment in which students practiced, classmate relationships, roles, goals and values, and activities, and areas of performance. It showed that the groups unsatisfied and in-between with the quality of practice have more intensified stress than the group with satisfaction. The study showed a slight (p<.01) difference amongst groups [(satisfaction group (M=2.17), group in between satisfaction and dissatisfaction (M=2.68), and dissatisfaction (M=2.96)) in the relationship between satisfaction with the quality of the clinical rotation and overall stress. It appeared that higher levels of stress were seen with lower satisfaction with the major. Overall, students' level of stress was correlated with age and grade level, level of satisfaction in the major and the quality of the clinical rotation. Furthermore, schools need to focus on improving the environment where students practice, classmate relationships, roles, goals and values, and activities, and areas of performance. Dental laboratory colleges should concentrate on the basic case with the quality of clinical rotation and the chosen major. More skillful teaching and properly assigned clinical rotations and classes, along with a strong practical knowledge base applicable to clinical rotations will be needed in order to address these sources of dissatisfaction.

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A Study about Output Filter of Paralleled Three-Phase Grid-Connected PV Inverters

  • Vu, Trung-Kien
    • 전력전자학회:학술대회논문집
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    • 전력전자학회 2011년도 전력전자학술대회
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    • pp.271-272
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    • 2011
  • The rising popularity of renewable energy sources resulted in development of the units of higher rated powers. As a result of the limited power handling capacity of individual devices, paralleling is the choice to increase the equipment rating, while keeping the THD of the current at the PCC within the agency specified standards. And their typical power circuit configuration limits the stress on individual devices to an appreciable extent. The main scope of this paper is the analysis of filter structure in paralleling inverter system's operation. Simulation results are shown to verify the theoretical analysis.

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Sustainable Management of Irrigation Water Withdrawal in Major River Basins by Implementing the Irrigation Module of Community Land Model

  • Manas Ranjan Panda;Yeonjoo Kim
    • 한국수자원학회:학술대회논문집
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    • 한국수자원학회 2023년도 학술발표회
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    • pp.185-185
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    • 2023
  • Agricultural water demand is considered as the major sector of water withdrawal due to irrigation. The majority part of the global agricultural field depends on various irrigation techniques. Therefore, a timely and sufficient supply of water is the most important requirement for agriculture. Irrigation is implemented in different ways in various land surface models, it can be modeled empirically based on observed irrigation rates or by calculating water supply and demand. Certain models can also calculate the irrigation demand as per the soil water deficit. In these implementations, irrigation is typically applied uniformly over the irrigated land regardless of crop types or irrigation techniques. Whereas, the latest version of Community Land Model (CLM) in the Community Terrestrial Systems Model (CTSM) uses a global distribution map of irrigation with 64 crop functional types (CFTs) to simulate the irrigation water demand. It can estimate irrigation water withdrawal from different sources and the amount or the areas irrigated with different irrigation techniques. Hence, we set up the model for the simulation period of 16 years from 2000 to 2015 to analyze the global irrigation demand at a spatial resolution of 1.9° × 2.5°. The simulated irrigation water demand is evaluated with the available observation data from FAO AQUASTAT database at the country scale. With the evaluated model, this study aims to suggest new sustainable scenarios for the ratios of irrigation water withdrawal, high depending on the withdrawal sources e.g. surface water and groundwater. With such scenarios, the CFT maps are considered as the determining factor for selecting the areas where the crop pattern can be altered for a sustainable irrigation water management depending on the available withdrawal sources. Overall, our study demonstrate that the scenarios for the future sustainable water resources management in terms of irrigation water withdrawal from the both the surface water and groundwater sources may overcome the excessive stress on exploiting the groundwater in major river basins globally.

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완속기시(Soft-start) 광조사 방식이 복합레진의 중합 및 수축응력에 미치는 효과 (EFFECT OF SOFT-START LIGHT CURING ON THE POLYMERIZATION AND THE CONTRACTION STRESS OF COMPOSITE RESIN)

  • 위유민;오유향;이난영;이창섭;이상호
    • 대한소아치과학회지
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    • 제32권2호
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    • pp.332-343
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    • 2005
  • 본 연구에서는 기존의 할로겐 광중합기를 이용하여 40초간 조사하여 복합레진을 중합한 경우와 플라즈마 광중합기를 이용한 고강도의 중합 및 완속기시 중합 방식, 그리고 LED 광중합기를 이용한 통법의 중합과 완속기시 중합 방식으로 복합레진을 중합하여 발생되는 수축응력을 비교하고 미세경도를 측정하여 중합도를 평가하였다. 내경 7mm, 외경 10mrn의 아크릴릭 주형을 제작하고 외면에 스트레인게이지를 부착시킨 뒤 각각의 광원에 따른 중합모드로 광중합 하였다. 광조사 시점부터 1초 간격으로 600초간 수축응력을 측정하였으며, 중합 24시간 후 각 군의 미세경도를 측정하여 통계 분석하였다. 수축응력 측정 후 시편을 종단하여 주사전자현미경으로 레진수복물과 아크릴릭 주형 계면을 관찰하였다. 이상의 실험을 통해 얻은 결과는 다음과 같다. 1. 플라즈마 광과 LED 광원의 완속기시 중합방식은 각각의 기본 중합방식에 비해 중합 10분 후에 수축응력 감소를 보였다(P<0.05). 2. 완속기시 중합방식의 플라즈마 광이 가장 낮은 수축응력을 보였으나 미세경도 또한 가장 낮았다(P<0.05). 3. 완속기시 중합방식의 LED 광중합은 기존의 할로겐 광과 LED 광중합 방법에 비하여 낮은 수축응력을 보였다(P<0.05). 4. 완속기시 중합방식의 LED 광으로 조사한 시편의 미세경도는 단일광도로 조사한 할로겐 광과 LED 광중합과 비교하여 유의할만한 차이가 나타나지 않았다(P>0.05). 5. 기존의 할로겐 광과 완속기시 중합방식의 LED로 중합한 시편이 플라즈마 광과 단일강도의 LED로 조사한 군보다 더 나은 변연봉쇄를 보였다.

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Effect of Reiki on Symptom Management in Oncology

  • Demir, Melike;Can, Gulbeyaz;Celek, Enis
    • Asian Pacific Journal of Cancer Prevention
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    • 제14권8호
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    • pp.4931-4933
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    • 2013
  • Reiki is a form of energy therapy in which the therapist, with or without light touch, is believed to access universal energy sources that can strengthen the body's ability to heal itself, reduce inflammation, and relieve pain and stress. There is currently no licensing for Reiki nor, given its apparent low risk, is there likely to be. Reiki appears to be generally safe, and serious adverse effects have not been reported. So in this article provides coverage of how to use Reiki in oncology services.

Thermomechanical interactions in transversely isotropic magneto thermoelastic solid with two temperatures and without energy dissipation

  • Lata, Parveen;Kaur, Iqbal
    • Steel and Composite Structures
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    • 제32권6호
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    • pp.779-793
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    • 2019
  • The purpose of this research paper is to depict the thermomechanical interactions in transversely isotropic magneto thermoelastic solid with two temperatures and without energy dissipation in generalized LS theories of thermoelasticity. The Laplace and Fourier transform techniques have been used to find the solution of the problem. The displacement components, stress components, and conductive temperature distribution with the horizontal distance are computed in the transformed domain and further calculated in the physical domain numerically. The effect of two temperature and relaxation time are depicted graphically on the resulting quantities.

Effects of process variables on morphology of palladium metal deposit in hydrochloric acid medium

  • kim Min-Seuk;Lee Jae-Chun;Kim Won-Back;Jeong Jin-Ki;Nam Chul-Woo
    • 한국지구물리탐사학회:학술대회논문집
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    • 한국지구물리탐사학회 2003년도 Proceedings of the international symposium on the fusion technology
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    • pp.642-647
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    • 2003
  • Palladium is widely used for several applications and recovery of palladium from secondary sources becomes increasingly important since palladium is one of maldistributed platinum group metals. Electrochemical recovery of dense palladium metal sheet from Pd leaching solution is a simple and easily controlled method. The surface morphology of the recovered Pd metal was significantly affected by current density and temperature. Dense deposit morphology was in higher stress state regardless of preparation condition under $55^{\circ}C$. Rising temperature up to $70^{\circ}C$ had a stress releasing effect besides densification of Pd deposit.

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