• 제목/요약/키워드: Challenge stress

검색결과 179건 처리시간 0.031초

Fracture properties of concrete using damaged plasticity model -A parametric study

  • Kalyana Rama, J.S.;Chauhan, D.R.;Sivakumar, M.V.N;Vasan, A.;Murthy, A. Ramachandra
    • Structural Engineering and Mechanics
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    • 제64권1호
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    • pp.59-69
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    • 2017
  • The field of fracture mechanics has gained significance because of its ability to address the behaviour of cracks. Predicting the fracture properties of concrete based on experimental investigations is a challenge considering the quasi-brittle nature of concrete. So, there is a need for developing a standard numerical tool which predicts the fracture energy of concrete which is at par with experimental results. The present study is an attempt to evaluate the fracture energy and characteristic length for different grades of concrete using Concrete Damage Plasticity (CDP) model. Indian Standard and EUROCODE are used for the basic input parameters of concrete. Numerical evaluation is done using Finite Element Analysis Software ABAQUS/CAE. Hsu & Hsu and Saenz stress-strain models are adopted for the current study. Mesh sensitivity analysis is also carried to study the influence of type and size of elements on the overall accuracy of the solution. Different input parameters like dilatation angle, eccentricity are varied and their effect on fracture properties is addressed. The results indicated that the fracture properties of concrete for various grades can be accurately predicted without laboratory tests using CDP model.

Urinary Cortisol Levels in Japanese Shorthorn Cattle before and after the Start of a Grazing Season

  • Higashiyama, Y.;Narita, H.;Nashiki, M.;Higashiyama, M.;Kanno, T.
    • Asian-Australasian Journal of Animal Sciences
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    • 제18권10호
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    • pp.1430-1434
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    • 2005
  • We conducted two experiments to assess the effect of transfer from housing to grazing on stress hormone secretion in cattle using urine samples. In a preliminary experiment, urine samples were collected following an adrenocorticotrophic hormone (ACTH) challenge, and cortisol levels in urine were compared with the levels in plasma. In a second experiment, urinary cortisol was measured before and after the start of a grazing season in 6 Japanese Shorthorn cows, all of which had experienced grazing before. In experiment 1, urinary cortisol showed a pattern of changes similar to that of plasma with a 0.5-h temporal lag time, and the peak levels were 4 to 10 times higher than the basal levels. In experiment 2, the urinary cortisol levels in cows did not change after the cows were let out to pasture, with no decreases in body weight. This study suggests that the transfer from housing to grazing did not affect physiological responses to cause high excretion of urinary cortisol in grazing-experienced cattle using a non-invasive sampling method.

강인성이 건강증진행위, 신체증상에 미치는 효과-여대생을 대상으로- (Hardiness as a Stress-resistance Resource and as a Determinant of Health -promoting Behavior: in a Sample of Nursing Students)

  • 이미라;소희영;송영신
    • 지역사회간호학회지
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    • 제9권1호
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    • pp.21-29
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    • 1998
  • This study was undertaken in order to examine the relationship of hardiness and health-promoting behavior and the effects of hardiness on stress-related physical symptoms. The subjects were 104 female nursing students of one college in Kongju. The instruments used for this study were a survey of general characteristics, hardiness(25 items), health-promoting behavior(44 items), and physical symptoms(35 items), Analysis of data was done by use of mean, Pearson correlation coefficient, stepwise regression and a hierarchical multiple regression with an SAS program. The results of this study are as follows. 1) Significant correlations between health -promoting behavior and subscales of hardiness, that is, control(r=-.35, P<.00l), commitment(r= -.29, P<.0l), and challenge(r= -.23, p<.05) were found. 2) Control was the highest factor predicting health -promoting behavior. 3) Main and buffering effects of hardiness on current physical symptoms were not found.

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3-(4′-hydroxyl-3′, 5′-dimethoxyphenyl) Propionic Acid Suppresses NO Production and Elevates GSH Levels in Murine Macrophages

  • Song, Young-Sun;Choi, Chun-Yeon;Suh, Hongsuk;Song, Yeong-Ok
    • Preventive Nutrition and Food Science
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    • 제9권3호
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    • pp.270-275
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    • 2004
  • Previous studies have shown that kimchi and kimchi-derived 3-(4'-hydroxyl-3', 5'-dimethoxyphenyl) propionic acid have anti-oxidative and hypolipidemic effects in rats and rabbits. This study was designed to investigate whether chemically synthesized 3-(4'-hydroxyl-3', 5' -dimethoxyphenyl) propionic acid (HDMPPA) may ameliorate oxidative stress through the regulation of nuclear factor KB (NFkB) activation in lipopolysaccharide (LPS)-stimulated RAW 264.7 murine macrophage cells. Treatment of RAW 264.7 cells with 400 uM of HDMPPA significantly reduced LPS-stimulated nitric oxide (NO) production. Treatments with HDMPPA at 100 uM to 400 uM concentrations significantly elevated glutathione (GSH) level. However, cell viability and thiobarbituric acid-reactive substances (TBARS) concentrations were not affected by the concentrations of HDMPPA used. The specific DNA binding activities of NFKB, a transcription factor which is sensitive to oxidative stress, were not down-regulated by HDMPPA treatments. These results suggest that HDMPPA may have weak anti-oxidative activity against LPS challenge by scavenging NO and stimulating GSH production.

Understanding intestinal health in nursery pigs and the relevant nutritional strategies

  • Kim, Sung Woo;Duarte, Marcos E.
    • Animal Bioscience
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    • 제34권3_spc호
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    • pp.338-344
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    • 2021
  • In the modern pig production, pigs are weaned at early age with immature intestine. Dietary and environmental factors challenge the intestine, specifically the jejunum, causing inflammation and oxidative stress followed by destruction of epithelial barrier and villus structures in the jejunum. Crypt cell proliferation increases to repair damages in the jejunum. Challenges to maintain the intestinal health have been shown to be related to changes in the profile of mucosa-associated microbiota in the jejunum of nursery pigs. All these processes can be quantified as biomarkers to determine status of intestinal health related to growth potential of nursery pigs. Nursery pigs with impaired intestinal health show reduced ability of nutrient digestion and thus reduced growth. A tremendous amount of research effort has been made to determine nutritional strategies to maintain or improve intestinal health and microbiota in nursery pigs. A large number of feed additives have been evaluated for their effectiveness on improving intestinal health and balancing intestinal microbiota in nursery pigs. Selected prebiotics, probiotics, postbiotics, and other bioactive compounds can be used in feeds to handle issues with intestinal health. Selection of these feed additives should aim modulating biomarkers indicating intestinal health. This review aims to define intestinal health and introduce examples of nutritional approaches to handle intestinal health in nursery pigs.

외래에서 흔히 접하는 배뇨 증상 - 배뇨장애를 중심으로 - (Common Urinary Symptoms in Outpatient Clinic - Voiding Dysfunction in Children -)

  • 김기혁;김영식
    • Clinical and Experimental Pediatrics
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    • 제48권6호
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    • pp.575-579
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    • 2005
  • Urinary incontinence is the most common urinary symptom in children and causes considerable anxiety in children and parents. In most cases, there is no underlying organic pathology and the longterm prognosis is excellent. Despite these reassuring facts, children with wetting problems can be a challenge for primary pediatrician. This is probably because the problem is poorly understood, there is no readily identifiable medical pathology, and because treatment is usually time consuming and arduous. There is a great demand for treatment because wetting is an unpleasant symptom that can cause a stress and anxiety in the family. There may also be other coexisting problems such as urinary tract infection, constipation, soiling, and behavioral or emotional difficulties. Despite the frequency and vexing nature of voiding dysfunction, physicians may not always obtain a careful history to identify and to treat children properly with this condition. This article addresses the comprehensive diagnostic and therapeutic approach to such children.

강인성 (Hardiness)의 개념 분석 (A Concept Analysis of Hardiness)

  • 이영애
    • 대한간호학회지
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    • 제24권4호
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    • pp.616-622
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    • 1994
  • Precise concept analysis has been neglected be-cause of a lack of understanding of its necessity and a lack of conceptual analytic knowledge. Concept analysis is the mental work of examining parts, phenomenon and the interrelated whole of a thing. Focus in this article is to extract the critical attributes of hardiness and make an operational delinition. The process of concept analysis is illustrated and documented using the analytic approach described by Walker and Avant (1983). To explore the explicit or implicit meanings of hardiness, existing literature was reviewed. The evolution of hardiness and the dictionary definitions were also added. Hardiness can be defined as follows : A condition of being inured to fatigue or hardship which has three subcomponents-challenge, control and commitment. Critical attributes of hardiness were extracted that may be used in naming the occurrence of the phenomenon. Model case, contrary case, borderline case and related case were described. Antecedents and consequences were explored. The defining critical attributes of hardiness are : 1. Resistance-hardiness involves resistance of stress or hardship. 2. Hardiness involves appraisal of change as a chance. 3. Hardiness implies interpretation of events and self as influential,. 4. Hardiness requires active involving reaction Implications for nursing and for further study are added.

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Strategies to Increase Exercise Compliance and Adherence for Breast Cancer Survivors: A Descriptive Review

  • Yang, Paul;Foroughi, Nasim;Kilbreath, Sharon
    • 국제물리치료학회지
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    • 제1권2호
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    • pp.79-90
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    • 2010
  • Breast cancer is the most frequently diagnosed cancer primarily affecting women and negatively impacting the individuals, families, and the health care system. Despite the well-known benefits of exercise for breast cancer survivors, rate of physical activity declines during adjuvant therapy and may not return to pre-diagnosis levels. In addition, low levels of adherence to exercise have been observed in this cohort. The challenge is to identify strategies that are effective in promoting exercise adherence. Several of the studies use social cognitive theory as a theoretical framework to design exercise interventions that encourage adherence. Within and without this framework, they have implemented interventions within the home and gym-based environments. Strategies used to encourage adherence to exercise programs and which are readily implemented in most situations have included distribution of print materials and pedometers, as well as recommendation from the oncologist. Other strategies that may be less feasible have included provision of trainers, gym memberships, regular phone-calls, and psychologist-lead stress management sessions.

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단결정 철의 소성에 대한 멀티스케일 모델링 (Multi-scale Modeling of Plasticity for Single Crystal Iron)

  • 전종배;이병주;장영원
    • 소성∙가공
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    • 제21권6호
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    • pp.366-371
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    • 2012
  • Atomistic simulations have become useful tools for exploring new insights in materials science, but the length and time scale that can be handled with atomistic simulations are seriously limiting their practical applications. In order to make meaningful quantitative predictions, atomistic simulations are necessarily combined with higher-scale modeling. The present research is thus concerned with the development of a multi-scale model and its application to the prediction of the mechanical properties of body-centered cubic(BCC) iron with an emphasis on the coupling of atomistic molecular dynamics with meso-scale discrete dislocation dynamics modeling. In order to achieve predictive multi-scale simulations, it is necessary to properly incorporate atomistic details into the meso-scale approach. This challenge is handled with the proposed hierarchical information passing strategy from atomistic to meso-scale by obtaining material properties and dislocation mobility. Finally, this fundamental and physics-based meso-scale approach is employed for quantitative predictions of the mechanical response of single crystal iron.

강인성 (hardiness)에 대한 문헌고찰 (The Concept of Hardiness : A Review of the Literature for Nursing)

  • 박명희
    • 대한간호학회지
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    • 제22권2호
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    • pp.227-237
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    • 1992
  • The purposes of this literature review were to identify the theoretical basis and components of the concept hardiness, trends in the study of hardiness it's application in nursing and issues in measurement. The concept of hardiness has been derived deductively from existential psychology and is composed of three components, control, commitment and challenge. In research, the characteristic of hardiness has been demonstrated as a motivating factor in resolving stressful situations and in adapting to actual health problems. With regard to the measurement of hardiness, because of it's low level of predictability related to health outcomes, it is recommanded that the component of be omited from the concept of hardiness. On the basis of this literature review, the following suggestions are proposed. 1. Considering the lack of empirical suport, the theory of hardiness needs to be evaluated. 2. There is a need for further study of hardiness in a broad variety of populations. 3. A valid, reliable and culturally appropriate instrument needs to be developed for health related research. 4. Analysis is needed of the relationship between hardiness and stress-resistance, and of the factors related to both.

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