• Molecules and Cells
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• 제40권4호
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• pp.280-290
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• 2017

Several lines of evidence suggest that endoplasmic reticulum (ER) stress plays a critical role in the pathogenesis of many neurodegenerative diseases such as Alzheimer's disease, Parkinson's disease, and amyotrophic lateral sclerosis. Protein tyrosine phosphatase 1B (PTP1B) is known to regulate the ER stress signaling pathway, but its role in neuronal systems in terms of ER stress remains largely unknown. Here, we showed that rotenone-induced toxicity in human neuroblastoma cell lines and mouse primary cortical neurons was ameliorated by PTP1B inhibition. Moreover, the increase in the level of ER stress markers ($eIF2{\alpha}$ phosphorylation and PERK phosphorylation) induced by rotenone treatment was obviously suppressed by concomitant PTP1B inhibition. However, the rotenone-induced production of reactive oxygen species (ROS) was not affected by PTP1B inhibition, suggesting that the neuroprotective effect of the PTP1B inhibitor is not associated with ROS production. Moreover, we found that MG132-induced toxicity involving proteasome inhibition was also ameliorated by PTP1B inhibition in a human neuroblastoma cell line and mouse primary cortical neurons. Consistently, downregulation of the PTP1B homologue gene in Drosophila mitigated rotenone- and MG132-induced toxicity. Taken together, these findings indicate that PTP1B inhibition may represent a novel therapeutic approach for ER stress-mediated neurodegenerative diseases.

• Journal of Biosystems Engineering
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• 제40권4호
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• pp.335-344
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• 2015

Purpose: Soybean growth is adversely affected by environmental stresses such as drought, extreme temperatures, and nutrient deficiency. The objective of this study was to develop a method for rapid measurement of drought stress in soybean plants using a hyperspectral fluorescence imaging technique. Methods: Hyperspectral fluorescence images were obtained using UV-A light with 365 nm excitation. Two soybean cultivars under drought stress were analyzed. A partial least square regression (PLSR) model was used to predict drought stress in soybeans. Results: Partial least square (PLS) images were obtained for the two soybean cultivars using the results of the developed model during the period of drought stress treatment. Analysis of the PLS images showed that the accuracy of drought stress discrimination in the two cultivars was 0.973 for an 8-day treatment group and 0.969 for a 6-day treatment group. Conclusions: These results validate the use of hyperspectral fluorescence images for assessing drought stress in soybeans.

• 항공우주시스템공학회지
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• 제9권4호
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• pp.31-36
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• 2015

The fatigue analysis for cutout panel used for the weight reduction of aircraft has been conventionally performed through the open hole concept using the reference stress and stress concentration factor (Kt). However, in the actual structure cases, the goal of weight reduction might be less meaningful due to the conservative approach induced by the difficulties of extracting the confident reference stress from FE-Analysis in the complicated loading behavior. Therefore a new approach is proposed in order to secure the effectiveness of weight reduction and validate the confidence of the analysis results using the interaction of max-min principal stress at the critical location of open hole edge line.

• The Journal of Asian Finance, Economics and Business
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• 제8권3호
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• pp.605-618
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• 2021

The use of human resources determines the success of enterprises. This study applies the questionnaire design method to analyze the relationship between job stress, job satisfaction, and job performance, noting that few studies have comparatively examined these variables between industries, especially between high-tech and traditional industries. The proposed assessment model in this study can facilitate decision-makers' ability to make the optimal business decisions through their personnel systems, thereby improving employee satisfaction and increasing job performance. This study found that in the traditional and high-tech industries, some demographic variables have significant differences in the job stress, job satisfaction and job performance, but the demographic variables that can significantly affect the differences in these job's variables are differences between industries. This study acknowledges that job stress and performance have a significantly negative correlation, and traditional industries will have more stress factors than high-tech industries. In addition, support for traditional industries exist in job satisfaction and performance has a significantly positive correlation, but not in high-tech industries. Job stress for performance has a significantly negative correlation in two industries. This study reconfirmed the relationship between job stress, satisfaction and performance, found some differences in this relationship and the respective industrial characteristics.

• 농촌지도와개발
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• 제29권3호
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• pp.143-153
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• 2022

Leisure activity characteristics are related to an individual's stress management as well as quality of life. This study analyzed the relationship between leisure activity characteristics, stress, and quality of life of healing tourists, and analyzed the moderating effect of involvement on rural healing tourism. For this purpose, this study analyzed 658 cases who experienced rural healing tourism. Among the characteristics of leisure activities, the conflict between work and leisure had a positive (+) effect on stress, and that stress had a negative (+) effect on the quality of life. Among the characteristics of leisure activities, social support was found to have a positive (+) effect on the quality of life. In the relationship between stress and quality of life, involvement on rural healing tourism was found to have a moderating effect. The results of this study indicate the importance of social support for work-life balance and leisure, suggesting that daily recovery through rural healing tourism has a positive effect on personal stress management as well as quality of life.

• 한국동물생명공학회지
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• 제34권3호
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• pp.173-182
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• 2019

This study was performed to evaluate the effect of heat stress on the status of physiological responses, blood parameter, serum T3 and cortisol, and heat shock proteins (HSP 27, 70, and 90) of Hanwoo cattle. Six Hanwoo steers (242.8 ± 7.2 kg of BW) were housed in the climate-controlled respiration chambers. The experiment consisted of 7 days (control; 0 day) at thermoneutral (air temperature (Ta) of 15℃ and relative humidity (RH) of 60%; temperature-humidity index (THI) = 64), and by 3 and 6 days (treatment groups) at heat stress (Ta of 35℃ and RH of 60%; THI = 87). Body temperature of each parts (frank, rump, perineum and foot) and rectal temperature elevated in heat stress groups (3 days and 6 days) than the control group (0 day). Respiration rates increased in 3 days and 6 days (88.5 ± 0.96 bpm and 86.3 ± 0.63 bpm, respectively) from 0 days (39.5 ± 0.65 bpm). Feed intake significantly decreased in heat stress groups (3 days and 6 days, 3.7 ± 0.14 kg and 4.0 ± 0.15 kg, respectively) than the control group (0 day, 5.0 ± 0.00 kg). In addition, final BW significantly decreased in heat stress groups (3 days and 6 days, 211.8 ± 4.75 kg and 215.5 ± 3.50 kg, respectively) than the control group (0 day, 240.0 ± 25.00 kg). However, heat stress has no significant effect on blood parameter, serum T3 and cortisol. Nevertheless, heat stress increased HSPs mRNA expression in liver tissue, and serum concentration of HSPs. Despite Hanwoo cattle may have high adaptive ability to heat stress, our results suggested that heat stress directly effect on body temperature and respiration rate as well as serum and tissue HSPs. Therefore, we are recommended that HSPs could be the most appropriate indicators of Hanwoo cattle response to heat stress.

• 대한기계학회논문집
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• 제19권5호
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• pp.1190-1201
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• 1995

Photoelastic experiment has been restricted by three significant problems such as the problems of modeling for a complicated body, of development of experimental model material, and of residual stress in photoelastic specimen. The residual stress in photoelastic model materials is caused by molding, cutting and time effects, etc.. Especially, large residual stress exists on the interface of photoelastic model material for bi-material. Small residual stress occurred in the photoelastic model materials is usually neglected in the photoelastic experiments. But the residual stress provides some errors in the results of photoelastic experiments. In this paper, the stress optic law which can be effectively applied to the phtoelastic model materials with residual stress is developed. By using this stress optic law, we can obtain good results from isochromatic fringe patterns of photoelastic experiment specimen in which residual stress are involved. The stress optic law can be applied to obtain good results of photoelastic experiment from composite materials or bimaterials.

• 한국보육지원학회지
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• 제11권1호
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• pp.395-413
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• 2015

본 연구의 목적은 어머니의 양육스트레스가 모유수유 영아와 비모유수유 영아의 발달에 미치는 영향력을 살펴보는 것이다. 이를 위해, 서울과 경기지역에 거주하는 생후 3개월의 영아 533명과 어머니를 대상으로, K-ASQ에 의한 영아발달 측정과 양육스트레스에 대한 설문조사를 실시하였다. 연구결과는 다음과 같다. 첫째, 모유수유 어머니가 비모유수유 어머니에 비해 양육스트레스 수준이 낮았고, 특히 부모역할 스트레스 수준이 더 낮은 것으로 나타났다. 둘째, 모유수유 영아가 비모유수유 영아에 비해 개인-사회성 발달이 더 양호한 것으로 나타났다. 셋째, 어머니의 양육스트레스는 모유수유 영아의 모든 발달에 영향을 미치며 특히 의사소통 발달에는 총 12.4%의 영향력을 미치는 것으로 나타났다. 반면, 비모유수유 영아의 발달에는 의사소통과 개인-사회성 발달에만 영향을 미치며 그 외 발달에 미치는 영향력은 유의하지 않았다. 넷째, 어머니의 양육스트레스 중에서도 부모역할 스트레스는 모유수유 영아와 비모유수유 영아의 발달에 부정적인 영향을 주는 주요인으로 나타났다. 본 연구결과를 토대로, 모유수유 실천과 어머니의 부모역할 스트레스 감소를 위한 가족과 사회의 지원방안에 대해 제안하였다.

• 한국분말야금학회:학술대회논문집
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• 한국분말야금학회 2006년도 Extended Abstracts of 2006 POWDER METALLURGY World Congress Part 1
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• pp.623-624
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• 2006

The behavior of hardmetals under cyclic loads is investigated. Unnotched specimens were employed to obtain practical information regarding fatigue in hardmetals. All the tested hardmetals exhibit an increase in the number of cycles until failure with a decrease in the maximum stress, i.e., the hardmetals exhibit a high fatigue sensitivity. The fatigue strength increases with the cobalt content. Although distinct fatigue limits, as observed in metals, cannot be observed, the calculated fatigue limit stress at $10^7$ cycles is found to be approximately 70% of the flexural strength, and the stress value exhibits a linear relationship with the flexural stress.

• 아동학회지
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• 제37권5호
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• pp.33-52
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• 2016

Objective: This study aimed to investigate the trajectory of maternal parenting stress during infancy according to the employment status of mothers when each year's depression was controlled and examine the longitudinal effects of parenting stress on affective parenting and socioemotional developmental outcomes for preschoolers. Methods: Using latent growth modeling, the first 4 waves of panel data collected from 2,078 mothers and their babies were analyzed. This nationwide data was provided from the 2008 Panel Study on Korean Children, conducted by the Korea Institute of Child Care and Education. Results: First, maternal parenting stress showed a linear increasing pattern, and there were individual differences in intercept and slope. Second, when each year's maternal depression was controlled, the intercept of parenting stress was lower, but the rate of increase was higher. In multiple group analyses, this increasing pattern of parenting stress was significant only in unemployed mothers. Lastly, the increase of unemployed mothers' parenting stress had direct effects on child emotionality and peer interaction and had an indirect effect on child peer interaction (mediated by affective parenting). Conclusion: The current study verified that the longitudinal effects of increasing parenting stress of unemployed mothers on affective parenting and child socioemotional development when maternal depression level was controlled. These results imply that we need to pay more attention to emotional health and resources of unemployed mothers and provide them with social support as well as employed mothers.