• 제목/요약/키워드: Stress of life

검색결과 6,152건 처리시간 0.033초

스프링강의 피로파괴에 미치는 압축잔류응력의 영향 (A Study on the effect of Compressive residual stress on fatigue crack propagation behavior of the spring steel)

  • 진영범;박경동
    • 대한기계학회:학술대회논문집
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    • 대한기계학회 2004년도 춘계학술대회
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    • pp.348-352
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    • 2004
  • Recently the steel parts used for automiles and trains are required to be used under higher stress than ever before in need of the weight down. However, threr are a lot of problems with developing such of fatigue strength and fatigue life are mainly focused on by adopting residual stress. And got the following characteristics from crack growth test carried out stress ratio. Fatigue life shows more improvement in the Un-peening material. And Compressive residual stress of surface on the Shot-peening processed operate resistance force of fatigue. So we cam obtain fallowings. (1) The fatigue crack growth rate on stage II is conspicuous with the size of compressive residual stress and is dependent of Paris equation. (2) Although the maximum compressive residual stress is deeply and widely formed from surface, fatigue life does not improve than when maximum compressive residual stress is formed in surface. (3) The threshold stress intensity factor range is increased with increasing compressive residual stress.

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The Relationships of End-of-life Care Stress with Compassionate Competence and Attitudes toward End-of-life Care among Pediatric Nurses

  • Park, Ki Young;Jeong, Jeong Hee
    • Journal of Hospice and Palliative Care
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    • 제24권4호
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    • pp.235-244
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    • 2021
  • Purpose: This study aimed to provide basic data for developing interventions to relieve the end-of-life care stress experienced by pediatric nurses by examining the relationships of end-of-life care stress with compassionate competence and attitudes toward end-of-life care. Methods: Data were collected via a survey that was conducted from September 10 to September 30, 2018 and administered to 113 nurses who had worked for more than 6 months in a pediatric unit at a tertiary hospital in Seoul, South Korea. The data were analyzed for frequency, percentage, mean, and standard deviation, and the independent t-test, one-way analysis of variance, and Pearson correlation analysis were conducted using SPSS version 25.0. Results: End-of-life care stress among pediatric nurses had a weak positive correlation (r=0.216, P<0.05) with compassionate competence and had no significant correlation with attitudes toward end-of-life care. Among the sub-factors of end-of-life care stress, psychological difficulties had a weak positive correlation with sensitivity (r=0.309, P<0.01) and communication (r=0.230, P<0.05), which are aspects of compassionate competence. Lack of knowledge about end-of-life care had a weak positive correlation with communication (r=0.209, P<0.05) as an aspect of compassionate competence. Conclusion: To improve the quality of end-of-life care provided by pediatric nurses, it is necessary to improve their compassionate competence and reduce their end-of-life care stress by developing education and support programs tailored to the characteristics of children and specific communication methods.

Metabolic changes during adaptation to saline condition and stress memory of Arabidopsis cells

  • Chun, Hyun Jin;Park, Mi Suk;Lee, Su Hyeon;Jin, Byung-Jun;Cho, Hyun Min;Hong, Young-Shick;Kim, Min Chul
    • 한국작물학회:학술대회논문집
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    • 한국작물학회 2017년도 9th Asian Crop Science Association conference
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    • pp.175-175
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    • 2017
  • To understand molecular mechanisms underlying adaptation of plant cells to saline stress and stress memory, we developed Arabidopsis callus suspension-cultured cells adapted to high salt. Adapted cells to high salt exhibited enhanced tolerance compared to control cells. Moreover, the salt tolerance of adapted cells was stably maintained even after the stress is relieved, indicating that the acquired salt tolerance of adapted cells was memorized. In order to characterize metabolic responses of plant cells during adaptation to high salt stress as well as stress memory, we compared metabolic profiles of salt-adapted and stress-memorized cells with control cells by using NMR spectroscopy. A principle component analysis showed clear metabolic discrimination among control, salt-adapted and stress-memorized cells. Compared with control cells, metabolites related to shikimate metabolism such as tyrosine, and flavonol glycosides, which are related to protective mechanism of plant against stresses were largely up-regulated in adapted cell lines. Moreover, coniferin, a precursor of lignin, was more abundant in salt-adapted cells than control cells. Cell morphology analysis using transmission electron microscopy indicated that cell wall thickness of salt-adapted cells was significantly induced compared to control cells. Consistently, salt adapted cells contained more lignin in their cell walls compared to control cells. The results provide new insight into mechanisms of plant adaptation to saline stress as well as stress memory in metabolic level.

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장기요양기관 노인의 일상스트레스, 자아탄력성이 삶의 질에 미치는 영향 (The Impacts of Daily Stress, Ego Resilience, and Quality of Life of the Elderly in Long-term Care Institutions)

  • 이강일;이종훈
    • 한국융합학회논문지
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    • 제8권6호
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    • pp.325-336
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    • 2017
  • 이 연구는 장기요양기관 노인의 일상스트레스, 자아탄력성, 삶의 질 변인 간 인과관계 모델을 설정하고 경로분석을 실시하였다. 수도권에 소재한 민간 노인장기요양기관의 이용자를 대상으로 최종 380명을 SPSS 22.0과 AMOS 22.0을 이용하여 일상스트레스, 자아탄력성, 삶의 질 변인 간 관계를 분석하였다. 연구결과, 첫째, 노인의 일상스트레스는 삶의 질에 부(-)적인 직접 효과가 있는 것으로 나타났다. 둘째, 노인의 자아탄력성은 삶의 질에 정(+)적인 직접 효과가 있었다. 셋째, 노인의 일상스트레스는 자아탄력성에 정(+)적인 직접 효과가 나타났다. 넷째, 노인의 자아탄력성을 매개로 일상스트레스는 삶의 질에 간접 효과 및 부분 매개 효과가 있는 것으로 나타났다. 따라서, 노인의 삶의 질을 향상하기 위해서는 일상스트레스를 감소하고 자아탄력성을 높이기 위한 프로그램 개발 및 제도적 지원 방안이 필요하다.

유방암 환자의 질병단계에 따른 가족 지지, 스트레스 및 삶의 질의 관계 (A Study on the Relationship among Family Support, Stress and Quality of Life on according to the Phases of Illness in Breast Cancer Patients)

  • 천상순;최소영
    • 여성건강간호학회지
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    • 제16권1호
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    • pp.10-19
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    • 2010
  • Purpose: The purpose of this study was to investigate the relationship among family support, stress and quality of life according to the phases of illness in breast cancer patients. Methods: A descriptive correlational study was employed with 121 breast cancer patients. The data was collected by using self reported questionnaire. Self reported data was collected by using the Family support scale, Perceived Stress Scale (PSS), and EORTC QLQ-BR23. Phases of illness consisted 1st phase, 2nd phase, 3rd phase. Results: The score of family supporting, stress and quality of life showed a statically differences according to the phase of illness. Family supporting and stress had negative relation in the first, second and third phase. Family supporting and quality of life in function area had positive relation in the first, second phase. There was no relation between family supporting and quality of life in symptom area. Stress, quality of life in symptom area and quality of life in function area had correlation in the first, third phase. Conclusion: This study suggest that the new nursing implementation should be considered according to the phase of illness in order to improve the family supporting and quality of life and reduce the stress in breast cancer patients through this study results.

Development of Stress-tolerant Crop Plants

  • Park, Hyung-In;Kang, Jung-Youn;Sohn, Hee-Kyung;Kim, Soo-Young
    • Journal of Plant Biotechnology
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    • 제4권2호
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    • pp.53-58
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    • 2002
  • Adverse environmental conditions such as drought, high salt and cold/freezing are major factors that reduces crop productivity worldwide. According to a survey, 50-80% of the maximum potential yield is lost by these "environmental or abiotic stresses", which is approximately ten times higher than the loss by biotic stresses. Thus, improving stress-tolerance of crop plants is an important way to improve agricultural productivity, In order to develop such stress-tolerant crop plants, we set out to identify key stress signaling components that can be used to develop commercially viable crop varieties with enhanced stress tolerance. Our primary focus so far has been on the identification of transcription factors that regulate stress responsive gene expression, especially those involved in ABA-mediated stress response. Be sessile, plants have the unique capability to adapt themselves to the abiotic stresses. This adaptive capability is largely dependent on the plant hormone abscisic acid (ABA), whose level increases under various stress conditions, triggering adaptive response. Central to the response is ABA-regulated gene expression, which ultimately leads to physiological changes at the whole plant level. Thus, once identified, it would be possible to enhance stress tolerance of crop plants by manipulating the expression of the factors that mediate ABA-dependent stress response. Here, we present our work on the isolation and functional characterization of the transcription factors.n factors.

하지정맥류 환자의 질병관련 지식과 스트레스 및 삶의 질 (Disease-related Knowledge, Stress, and Quality of Life in Patients with Varicose Veins)

  • 이설희;유양숙
    • Journal of Korean Biological Nursing Science
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    • 제18권1호
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    • pp.60-67
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    • 2016
  • Purpose: The purpose of this study was to investigate the disease-related knowledge, stress and quality of life for the patients with varicose veins. Methods: Data were collected via questionnaire from 138 patients with varicose veins in C University Hospital in Korea from November in Korea 2012 to August 2013. Results: Knowledge of the symptoms and diagnosis was the lowest. The scores from patients with disease-related knowledge tended to be low for both subjects over the age of 60 and subjects with low education (less than high school). The score for stress over complications was the highest. The level of stress is higher for women, subjects without spouses, subjects with higher severity of disease and patients who had been taking hormones in the past or are still taking hormones. The disease-related quality of life tended to be lower for women and subjects without spouses. 21% of the variance in quality of life was explained by the level of disease-related stress, disease severity and knowledge. Conclusion: Education and the management of nurses to improve disease-related knowledge for patients with varicose veins is highly recommended. Intervention, by reducing stress, is necessary to improve the quality of life for women, subjects without spouses, and subjects with higher severity of the disease.

경기지역 여자고등학생의 과민성 장 증후군 빈도와 입시 스트레스, 정신 건강, 삶의 질에 관한 연구 (Frequency of Irritable Bowel Syndrome, Entrance Examination Stress, Mental Health, and Quality of Life among Adolescent Women)

  • 박효정;임선영
    • 기본간호학회지
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    • 제16권2호
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    • pp.171-180
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    • 2009
  • Purpose: This study was done to examine the frequency of irritable bowel syndrome (IBS), entrance examination stress, mental health, and quality of life among adolescent women. Methods: A survey conducted to collect data from 925 adolescent women in Gyeonggi Province. The measurements included the Rome III criteria (to diagnose IBS), the entrance examination stress scale (to evaluate stress), symptom check list90R (SCL-90R to evaluate mental health), and World Health Organization Quality of Life Abbreviated Version (WHOQOL-BREF to evaluate quality of life). Frequency, $X^2$-tests, t-test, and analysis of variance (ANOVA) with the SPSS 16.0 program were used to analyze the data. Results: The frequency of IBS in the women was 22.8%. One hundred thirty eight women (65.4%) had the mixed constipation and diarrhea subtype of IBS. Compared to the women without IBS, those with IBS reported significantly higher scores on entrance examination stress scale, SCL-90R, all subscales of SCL-90R, and lower scores on WOLQOL-BREF. Conclusion: Nursing interventions targeting adolescent women with IBS should be developed in order to alleviate the associated stress and mental health and to promote quality of life.

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Celecoxib-mediated activation of endoplasmic reticulum stress induces de novo ceramide biosynthesis and apoptosis in hepatoma HepG2 cells

  • Maeng, Hyo Jin;Song, Jae-Hwi;Kim, Goon-Tae;Song, Yoo-Jeong;Lee, Kangpa;Kim, Jae-Young;Park, Tae-Sik
    • BMB Reports
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    • 제50권3호
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    • pp.144-149
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    • 2017
  • Ceramides are the major sphingolipid metabolites involved in cell survival and apoptosis. When HepG2 hepatoma cells were treated with celecoxib, the expression of the genes in de novo sphingolipid biosynthesis and sphingomyelinase pathway was upregulated and cellular ceramide was elevated. In addition, celecoxib induced endoplasmic reticulum (ER) stress in a time-dependent manner. SPTLC2, a subunit of serine palmitoyltransferase, was overexpressed by adenovirus. Adenoviral overexpression of SPTLC2 (AdSPTLC2) decreased cell viability of HEK293 and HepG2 cells. In addition, AdSPTLC2 induced apoptosis via the caspase-dependent apoptotic pathway and elevated cellular ceramide, sphingoid bases, and dihydroceramide. However, overexpression of SPTLC2 did not induce ER stress. Collectively, celecoxib activates de novo sphingolipid biosynthesis and the combined effects of elevated ceramide and transcriptional activation of ER stress induce apoptosis. However, activation of de novo sphingolipid biosynthesis does not activate ER stress in hepatoma cells and is distinct from the celecoxib-mediated activation of ER stress.

복합재료 피로 수명 분포에 관한 고찰 (Analysis on fatigue life distribution of composite materials)

  • 황운봉;한경섭
    • 대한기계학회논문집
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    • 제12권4호
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    • pp.790-805
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    • 1988
  • 본 연구에서는 유리섬유 강화 에폭시 복합재료의 파괴 강도와 피로 수명을 정 규분포, 로그 정규 분포와 2모수 및 3모수 Weibull 분포 함수의 기대값으로 살펴 보았 다. 2연속 응력 피로 실험 [작은 응력에서 큰 응력으로의 실험(low-high test), 큰 응력에서 작은 응력으로의 실험(high-low test)]의 결과도 분포 함수들을 사용하여 분 석하였다. 비통계학적 누적 손상 법칙들(non-statistical cumulative damage rules) 을 2연속 응력 피로 수명 분산 예측에 이용하기 위해서 동등 순위 가정(equal rank assumption)을 확장하여 수정하였다. 수정한 누적 손상 모형은 Miner의 법칙, Brou- tman과 Sahu의 손상모형 및 Hashin과 Rotem의 모형 등이다.