• BMB Reports
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• v.48 no.3
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• pp.184-189
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• 2015

Src homology 2-containing protein tyrosine phosphatase 2 (SHP-2) is known to protect neurons from neurodegeneration during ischemia/reperfusion injury. We recently reported that ROS-mediated oxidative stress promotes phosphorylation of endogenous SHP-2 in astrocytes and complex formation between caveolin-1 and SHP-2 in response to oxidative stress. To examine the region of SHP-2 participating in complex formation with caveolin-1, we generated three deletion mutant constructs and six point mutation constructs of SHP-2. Compared with wild-type SHP-2, binding of the N-SH2 domain deletion mutant of SHP-2 to p-caveolin-1 was reduced greatly, using flow cytometric competitive binding assays and surface plasmon resonance (SPR). Moreover, deletion of the N-SH2 domain of SHP-2 affected $H_2O_2$-mediated ERK phosphorylation and Src phosphorylation at Tyr 419 in primary astrocytes, suggesting that N-SH2 domain of SHP-2 is responsible for the binding of caveolin-1 and contributes to the regulation of Src phosphorylation and activation following ROS-induced oxidative stress in brain astrocytes.

• BMB Reports
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• v.43 no.9
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• pp.622-628
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• 2010

Dimethyl sulfoxide (DMSO) can be reduced to dimethyl sulfide by MsrA, which stereospecifically catalyzes the reduction of methionine-S-sulfoxide to methionine. Our previous study showed that DMSO can competitively inhibit methionine sulfoxide reduction ability of yeast and mammalian MsrA in both in vitro and in vivo, and also act as a non-competitive inhibitor for mammalian MsrB2, specific for the reduction of methionine-R-sulfoxide, with lower inhibition effects. The present study investigated the effects of DMSO on the physiological antioxidant functions of methionine sulfoxide reductases. DMSO elevated hydrogen peroxide-mediated Saccharomyces cerevisiae cell death, whereas it protected human SK-Hep1 cells against oxidative stress. DMSO reduced the protein-carbonyl content in yeast cells in normal conditions, but markedly increased protein-carbonyl accumulation under oxidative stress. Using Msr deletion mutant yeast cells, we demonstrated the DMSO's selective inhibition of the antioxidant function of MsrA in S. cerevisiae, resulting in an increase in oxidative stress-induced cytotoxicity.

• BMB Reports
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• v.42 no.3
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• pp.142-147
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• 2009

Small-molecule inhibitors of protein kinases have contributed immensely to our understanding of biological signaling path-ways and have been exploited therapeutically for the treatment of cancers and other disease states. The pyridinyl imidazole compounds SB 203580 and SB 202190 were identified as ATP competitive antagonists of the p38 stress-activated protein kinases and have been widely used to elucidate p38-dependent cellular processes. Here, we identify SB 203580 and SB 202190 as potent inhibitors of stress-induced CREB phosphorylation on Serine 111 (Ser-111) in intact cells. Unexpectedly, we found that the inhibitory activity of SB 203580 and SB 202190 on CREB phosphorylation was independent of p38, but instead correlated with inhibition of casein kinase 1 (CK1) in vitro. The inhibition of CK1-mediated CREB phosphorylation by concentrations of pyridinyl imidazoles commonly employed to suppress p38, suggests that in some cases conclusions of p38-dependence derived solely from the use of these inhibitors may be invalid.

• Journal of Wetlands Research
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• v.22 no.2
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• pp.113-120
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• 2020

For the conservation of both Sericinus montela (vulnerable species by red book of Korea) and A. contorta, we investigated environmental factors affecting the growth and reproduction of Aristolochia contorta. We selected four A. contorta habitats at Gapyeong, Pyeongtaek, Cheongju, and Yeoju in Korea and surveyed community and habitat characteristics of companion species, herbivore appearance, support types, and soil physicochemical properties in July and October, 2018. Habitat environments and the growth and reproduction characteristics of A. contorta were different according to four habitats of different regions. In particular, the fastest growth speed and earliest flowering and fruiting were observed in Pyeongtaek. Growth of A. contorta in Cheongju and Yeoju were interrupted by aboveground damage from human disturbance. In this study, support types seemed to be important for growth speed of A. contorta. Flowering and fruiting timing were likely to be related to combined effects of soil cation contents and competitive and herbivore stresses. Therefore, providing effective support and reducing biological stress should be necessary for stable growth and proper flowering and fruiting timing of A. contorta. In addition, experimental evidence would be needed to figure out the effect of soil cation and biological stress on flowering and fruiting of A. contorta in detail.

• Steel and Composite Structures
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• v.18 no.4
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• pp.853-871
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• 2015

Up to now, Japan has more than 200 corrugated steel web composite beam bridges which are under construction and have been constructed, and China has more than 30 corrugated steel web composite beam bridges. The bridge type includes the simply supported beam, continuous beam, continuous rigid frame and cable stayed bridge etc. The section form has developed to the single box and multi-cell box girder from the original single box and single chamber. From the stress performance and cost saving, the span range of 50~150 m is the most competitive. At present, the design mostly adopts the computational analytical method combining the spatial bar system model, plane beam grillage model and solid model. However, the spatial bar system model is short of the refinement analysis on the space effect, such as the shear lag effect, effective distribution width problem, and eccentric load factor problem etc. Due to the similarity of the plane beam grillage method in the equivalence principle, it cannot accurately reflect the shearing stress distribution and local stress of the top and bottom plates of the box type composite beam. The solid model is very difficult to combine with the overall calculation. Moreover, the spatial grid model can achieve the refinement analysis, with the integrity of the analysis and the comprehensiveness of the stress checking calculation, and can make up the deficiency of the analytical method currently. Through the example verification of the solid model and spatial grid model, it can be seen that the calculation results for the stress and the displacement of two models are almost consistent, indicating the applicability and precision of the spatial grid model.

• Journal of Venture Innovation
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• v.6 no.3
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• pp.149-164
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• 2023

Today, when innovation and creativity become increasingly important, management of human resources is a key factor for corporate performance and competitive advantage. Corporate are implementing and introducing various types of support methods for members to achieve goals and improve organizational performance. Organizational culture and organizational trust affect the cognitive and emotional state of members. Furthermore, it can bring about changes in organizational performance such as job stress and job satisfaction. From an institutional point of view, work-life balance is also a major factor affecting organizational performance. The imbalance between work and life leads to a decline in organizational performance, such as decreased morale and dissatisfaction with work. In relation to work-life balance, the low birth rate problem intensified and the importance began to emerge. Therefore, the government has implemented various policy support for workers' work-life balance, and the "52-hour workweek" is a representative example. This study analyzed the effect of organizational culture applying the competitive value model on workers' job stress. In addition, the mediating effects of overtime work per week and organizational trust were analyzed. Job stress corresponds to a prerequisite stage that affects job commitment, job satisfaction, and turnover intention. However, research measuring job stress by organizational performance is insufficient. In addition, there are few studies analyzing the relationship between overtime and organizational performance. Considering this, it is necessary to understand the influence relationship. The results of the study are as follows. First, a hierarchical culture increases the job stress of workers. On the other hand, innovation-oriented, relationship-oriented, and competition-oriented corporate culture reduce job stress. Second, a hierarchical culture has reduced trust in the organization, and other organizational cultures have increased trust in the organization. Third, relationship-oriented and competition-oriented organizational culture reduced overtime. Innovation-oriented, hierarchical-oriented culture increased overtime Fourth, organizational trust and overtime have the effect of mediating organizational culture and job stress. Based on these analysis results, this study presented academic and political implications.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2009.04b
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• pp.17-17
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• 2009

We report the invention of a direct growth method termed On-Film Formation of Nanowire (OFF-ON) for making high-quality single-crystal nanowires, i.e. Bi and $Bi_2Te_3$, without the use of conventional templates, catalysts, or starting materials. We have used the OFF-ON technique to grow single crystal semi-metallic Bi and compound semiconductor $Bi_2Te_3$ nanowires from sputtered Bi and BiTe films after thermal annealing, respectively. The mechanism for nanowire growth is stress-induced mass flow along grain boundaries in the polycrystalline films. OFF-ON is a simple but powerful method for growing perfect single-crystal semi-metallic and compound semiconductor nanowires of high aspect ratio with high crystallinity that distinguishes it from other competitive growth approaches that have been developed to date. Our results suggest that Bi and $Bi_2Te_3$ nanowires grown by OFF-ON can be an ideal material system for exploring their unique thermoelectric properties due to their high-quality single crystalline and high conductivity, which have consequence and relevance for high-efficiency thermoelectric devices.

• Journal of Medicine and Life Science
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• v.17 no.3
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• pp.86-93
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• 2020

The study aimed to understand medical students' experiences of emotional changes, including their method of adapting to experiences, and the effect of the experiences in shaping their identities. We interviewed 12 medical students who were finishing their 1-year clinical internship in 2016. Data on their opinions and reasons for emotional changes during their school life were obtained. The descriptive phenomenological approach was applied to analyze the interviews. Their stress came from disappointment in themselves, competitive environment, observing a change in their personalities, meeting their parents' expectations, and interpersonal relations. The interviewees adjusted to the medical study by exercising self-control in their studies and daily lives, by practicing self-acceptance and observing their state of mind, and by breaking free from the competition-driven environment and obsession with grades. In addition, they cultivated endurance and found external support. Finally, they achieved self-efficacy and were comfortable in their identity as medical students. They still had to address the stress from working relationships and the difficulty in balancing studies and life. The medical students' self-evaluation and compulsive tendencies increased during the medical course due to the burden of studies. They evolved by learning self-control and introspection and seeking ways to adapt. Understanding this growth process of medical students will improve student support in medical schools.

• Management & Information Systems Review
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• v.39 no.2
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• pp.77-94
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• 2020

While the importance of the service industry has increased at the national economy level, the service rate and job satisfaction of the flight attendants in the aviation service industry are not high. In this regard, this study aims to recognize what factors can reduce their job stress in the emotional work environment, and how job stress affects their attitude and job performance. More specifically, the current study tries to investigate how flight attendants' positive psychological status affect their job stress, organizational commitment, and knowledge sharing in the aspect of job performance. The main five constructs in these interrelationships include the flight attendants' positive psychological capital, leader-member exchange(LMX), job stress, organizational commitment, and knowledge sharing. This study conducted a quantitative research with 390 questionnaire for flight attendants, and analyzed the data using SPSS/PC version 20.0 and structural equation modeling program of AMOS 20.0. The findings show that the favorable leader-member exchange relationship between flight attendants plays a significant role in lowering job stress, while high job stress has a negative effect on organizational commitment and knowledge sharing. The result also shows that personal positive psychological capital acts as a trigger to influence other factors. Therefore, this study suggests that it is essential for airlines not only to promote an organizational system to support the flight attendants' emotional work but also to maintain a positive psychological state for securing competitive human resources.

• Korean Medical Education Review
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• v.14 no.2
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• pp.59-63
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• 2012

Current medical students are a distinct new generation who can be distinguished from the previous generation. Therefore, a clear understanding of their characteristics is vital in developing an appropriate educational program for them. The purpose of this article is to explore the characteristics of the current generation of high achieving medical students. Notable characteristics that define this generation include the following: they feel they are special, and they are sheltered, confident, highly optimistic, pressured, conventional, and have a strong desire to achieve. They are the digital generation, who can obtain information through various forms of technology. Furthermore, they are high achieving students in highly competitive educational environments. It has been suggested that various teaching methods be used in the medical school classroom. Using digital methods could be crucial in providing high-quality medical education. Educators should pay more attention to students' psychosocial development and help them to effectively cope with their academic stress.