• The Plant Pathology Journal
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• v.30 no.2
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• pp.168-177
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• 2014

Plant has possessed diverse stress signals from outside and maintained its fitness. Out of such plant responses, it is well known that mitogen-activated protein kinase (MAPK) cascade plays important role in wounding and pathogen attack in most dicot plants. However, little is understood about its role in wounding response for the economically important monocot rice plant. In this study, therefore, the involvement of MAPK was investigated to understand the wounding signaling pathway in rice. The OsMPK1 was rapidly activated by wounding within 10 min, and OsMPK1 was also activated by challenge of rice blast fungus. Further analysis revealed that OsMKK4, the upstream kinase of OsMPK1, phosphorylated OsMPK1 by wounding in vivo. Furthermore, OsMPK1 directly interacted with a rice defense-related transcription factor OsWRKY53. To understand a functional link between MAPK and its target transcription factor, we showed that OsMPK1 activated by the constitutively active mutant $OsMKK4^{DD}$ phosphorylated OsWRKY53 in vitro. Taken together, components involving in the wounding signaling pathway, OsMKK4-OsMPK1-OsWRKY53, can be important players in regulating crosstalk between abiotic stress and biotic stress.

• Nuclear Engineering and Technology
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• v.55 no.4
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• pp.1382-1399
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• 2023

Pressure relief valve (PRV) is one of the important control valves used in nuclear power plants, and its sealing performance is crucial to ensure the safety and function of the entire pressure system. For the sealing performance improving purpose, an explicit function that accounts for all design parameters and can accurately describe the relationship between the multi-design parameters and the seal performance is essential, which is also the challenge of the valve seal design and/or optimization work. On this basis, a surrogate model-based design optimization is carried out in this paper. To obtain the basic data required by the surrogate model, both the Finite Element Model (FEM) and the Computational Fluid Dynamics (CFD) based numerical models were successively established, and thereby both the contact stresses of valve static sealing and dynamic impact (between valve disk and nozzle) could be predicted. With these basic data, the polynomial chaos expansion (PCE) surrogate model which can not only be used for inputs-outputs relationship construction, but also produce the sensitivity of different design parameters were developed. Based on the PCE surrogate model, a new design scheme was obtained after optimization, in which the valve sealing stress is increased by 24.42% while keeping the maximum impact stress lower than 90% of the material allowable stress. The result confirms the ability and feasibility of the method proposed in this paper, and should also be suitable for performance design optimizations of control valves with similar structures.

• Geomechanics and Engineering
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• v.38 no.1
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• pp.15-28
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• 2024

The rapid development of the economy has compelled the widen of highways, and the main challenge of this undertaking lies in the uneven settlement of road embankments. Through field and numerical experiments, this study explores the deformation mechanism of shallow buried pipelines due to road widening. The utilization of Plaxis3D software, which is adapt at simulating complex engineering geological conditions, enables the simulation of the settlement of both the central and right-side road embankments. Comparing with other numerical software such as ABAQUS and COMSOL, Plaxis provided more constitutive models including HS, HSS and Hoek-Brown model. The work concludes that the uneven settlement of road cross-sections is positively correlated with the horizontal distance from the pipeline, with a maximum settlement of 73 mm observed after construction. Furthermore, based on the Winkler's assumption, theoretical settlement and stress calculation methods are established. Results indicate that the maximum difference between the calculated values of this formula and simulated values is 1.9% and 7%, respectively. Additionally, the study investigates the stress and settlement of the pipeline's top under different angles to understand its behavior under various conditions. It finds that with traffic loads applied to the new embankment, a lever effect occurs on the lower pipeline, with the fulcrum located within the central isolation zone, leading to a transition in curve type from "single peak and single valley" to "double peak and single valley." Moreover, the settlement of pipelines on both sides of the central isolation zone and the normal stress of the pipeline's top section are symmetrical.

• Journal of fish pathology
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• v.22 no.3
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• pp.253-262
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• 2009

We conducted bacteriological and histopathological analysis for olive flounder Paralichthys olivaceus after experimental infection with Streptococcus parauberis (FP2284) isolated from diseased olive flounder under different stress conditions. Experimental challenge was performed in healthy flounder (40.4 g in average body weight) by intraperitoneal (i.p.) injection with $2{\times}10^{8}$ CFU/fish under normal (no stress) or netting (for 2 min, twice/day) stress condition. The cumulative mortalities of no-stress and netting stress group were 70% and 95%, respectively. The most prevalent changes observed in experimentally infected flounder were darkness of skin and inflammation of the heart. Severe pericarditis, myocarditis and fibrosis were observed in the heart of the affected flounder. The results of viable counts showed the number of bacteria of the heart tissue was maintained over the $10^{4}$ CFU $g^{-1}$ heart for 3 weeks after inoculation. Histological lesions of the heart was more extensive and gradual decrease in bacterial numbers of heart tissue was delayed under stress condition.

• The Journal of the Korea Contents Association
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• v.15 no.11
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• pp.238-249
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• 2015

This study was carried out to analyze the mediating effect of self-soothing ability in the relationship of job environment stress and psychological burnout of youth counselors. To achieve the study purpose, a survey was executed on 150 counselors who gathered for a academic meeting held at Korea National University of Education with the theme of youth counseling on May 5, 2015. The participants included nation-wide counselors working at public agencies, schools, university and colleges, and private counseling offices. Analysis was executed for 113 questionnaires found valid with SPSS v.20, and study findings are as follows: first, career and working conditions youth counselors showed no difference in job environment stress between groups; second, 'lack of challenge' and 'role ambiguity' were found to affect psychological burnout; third, 'resilience' and 'self-disclosure' were found to affect psychological burnout; fourth, self-soothing ability was shown to have a mediating effect in the relationship between job environment stress and psychological burnout of youth counselors. This result will contribute to helping develop programs to cope with stress faced by both experienced youth counselors and counselors in general.

• The Korean Journal of Rheology
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• v.11 no.1
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• pp.18-27
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• 1999

Predicting the deformation behaviors of sheets in thermoforming processes has been a daunting challenge due to the strong nonlinearities arising from very large deformations, mold-polymer contact condition and hyperelasticity constitutive equations. Nonlinear numerical analysis is always required to face this challenge especially for realistic processing conditions. In this study a 3-D algorithm and the membrane approximation are developed for thermoforming processes. The constitutive equation is expressed in terms of the 2nd Piola-Kirchhoff stress tensor and the Cauchy-Green deformation tensor. The 2-term Mooney-Rivlin model is used for the material model equation. The algorithm is established by the finite element formulation employing the total Lagrangian coordinate. The deformation behavior and the stress distribution results of 3-D algorithm with various point boundary conditions are compared to those of the membrane approximation algorithm. Also, the slip boundary condition and the no-slip boundary condition are applied for the systems that have molds. Finally, the effect of sheet temperatures on the final thickness distribution is investigated for the ABS material.

• Journal of Venture Innovation
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• v.3 no.1
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• pp.143-163
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• 2020

When we assume the transition to a knowledge management society, what factors should be differentially added to the characteristics of CEOs of small enterprises to enhance management performance? This can be done by measuring the core competence of the CEO who is an importance asset of the small firms. This study focuses on the following four inquiries to clarify the relationship among the core competence of the CEO, the knowledge management and the performance of the firms. First, we test the influence of the core competence of CEO on business performance. Second, we explore the effects of CEO characteristics on the knowledge management and the performance of the firm. Third, we test whether knowledge management has a mediating effect in the relationship between the characteristics of CEO which is a parameter, and the business performance of the firm which is a dependent variable. Fourth, for the sake of a deeper understanding of the CEO of the small firms, we conduct t-test or multiple comparison to find out the statistically significant differences among means of the main variables such as demographic characteristics, work experience, and entrepreneurship. The academic contribution of this study is to verify the characteristics of the CEO, which influence the business performance:the global competence, challenge spirit, interpersonal flexibility and stress tolerance, in connection with the knowledge management of small firms. The practical contribution of this study is to test whether CEOs can demonstrate successful business performance through knowledge management rather than measuring business performance after a certain period of time through profit and loss statements in this era of uncertainty.

• Journal of Korean Academy of Nursing
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• v.27 no.3
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• pp.541-549
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• 1997

This study was done to describe health promoting lifestyle and determine affecting factors in elderly based on the Heath Promotion Model by Pender. Cognitive-perceptual factors that were included in this study were self-efficacy and hardiness. Modifying factors were demographic characteristics (sex, age, partner, previous illness, education level. income and religion). The specific purpose of this study was to examine the relationships of self-efficacy, hardiness and the demographic chasteristics to health promoting lifestyle and to determine causal factors affecting the elderly. The subjects were a volunteer sample of 98 elderly in one city in? The instruments for this study were Health Promoting Lifestyle Profile(47items, 4scale), Health Related Hardiness Scale(22i1ems, 6scale), general Self-Efficacy Scale(13i1ems, 5scale). Frequency, percentage, t-test, ANOVA, Pearson's correlation coefficient and Stepwise Multiple regression technique with SAS program were used to analyse the data. The Results of the study are as follows : 1) The average item score for the health promoting lifestyle was 2.63, the highest score on the subscales was interpersonal support (M=3.3), followed by self-actulization(M=2.9), nutrition(M=2.8), stress management(M=2.7), health responsibility(M=2.1) with the lowest bring exercise(M=2.0) 2) A significant difference between education level, income, religion and health promoting lifestyle were found. 3) All of the subscales on health promoting lifestyle were positively related to total hardiness (r=0.330, p<0.001). The hardiness subscale of control was positively related to self-actulization(r=0.276, p<0.01), and commitment was positively related to self-actualization(r=0.315, p<0.001), exercise /nutrition(r=0.245, p<0.01), interpersonal support(r=0.278, p<0.01), stress management(r=0.250, p<0.01). Challenge was positively related to self-actualization(r=0.315, p<0.001), exercise /nutrition(r=0.245, p<0.01). There was no significant correlation between self-efficacy and all of the subscales of health promoting lifestyle. Self-efficacy showed a significant correlation only with control(r=0.469, p<0.001), comittment(r=0.507, p<0.001), challenge (r=0.489, p< 0.001). 4) Comittment, self-efficacy and income explained 25.01% of the variance for the total health promoting lifestyle. The results of this study show that commitment, self efficacy and income predicted the health promoting lifestyle of the elderly. So health promoting programs that increase commitement and self-efficacy should be developed to promote a healthy lifestyle of the elderly, especially those who have low income.

• Asian-Australasian Journal of Animal Sciences
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• v.18 no.10
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• pp.1445-1450
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• 2005

This experiment was conducted to evaluate the effect of feed withdrawal (F) and heat acclimatization (A) on malebroiler and -layer chickens responses to acute heat stress (AHS) at four weeks of age. Totals of ninety male chicks of broiler or layer type were randomly allocated into 30 pens of grower batteries with raised wire floors. Chicks were subjected to F and A three times a week through the first three weeks of age. At each time, feed withdrawal and heat acclimatization (T = $35^{\circ}C$) lasted for six and four hours, respectively. Feed consumption (FC), body weight (BW), and feed conversion ratio (FCR) were recorded weekly for broiler type chickens only. At four weeks of age, all groups of chickens were exposed to AHS (T = $39{\pm}1^{\circ}C$) for three hours. Before and after AHS challenge, body temperature (Tb), heterophil (H), and lymphocyte (L) counts were recorded, and H/L ratio was calculated. Antibody (Ab) response to sheep red blood cells (SRBC) was assessed from all treatments without being exposed to AHS. Group F of broiler-type chickens weighed less (p<0.05) compared to control group. Also, both A and F groups of broiler-type chickens consumed less (p<0.05) feed when compared to control group. Acute heat stress elevated Tb of all treatment groups, however the increase was more profound (p<0.001) in broiler chicks. Broiler chicks of both A and F groups showed a tendency to have higher (p = 0.08) Tb when compared to control group. Acute heat stress elevated (p<0.001) H/L ratio in both types of chickens. Broiler chicks maintained higher (p<0.001) H/L ratio. Both F and A groups reduced (p<0.01) the level of elevation in H/L ratio compared to control groups of both types of chickens. Neither A nor F group affected the Ab production in response to SRBC. However, there was a tendency towards higher Ab responses in F group when compared to other groups in both types of chickens. Results of the present study demonstrate that previous history of feed withdrawal or episodes of heat exposures improved chicks'physiological withstanding of AHS and a tendency to improved humoral immune response.

• Fisheries and Aquatic Sciences
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• v.18 no.3
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• pp.273-281
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• 2015

The follistatin (FST) gene encodes a monomeric glycoprotein that plays a role in binding and inhibiting the functions of members of the transforming growth factor (TGF)-${\beta}$ superfamily. Thus, FST facilitates a wide variety of functions, ranging from muscle growth, to inflammation and immunity. In this study, we sought to characterize an FST counterpart, RbFST, which was identified from rock bream Oplegnathus fasciatus. The RbFST cDNA sequence (2,419 bp) contains a 933-bp open reading frame (ORF) that encodes a putative amino acid sequence for RbFST (35 kDa). The putative amino acid sequence contains a Kazal-type serine protease inhibitor domain (51-98 residues) and an EF-hand, calcium-binding domain (191-226 residues). Additionally, this sequence shares a high identity (98.7%) with the Siniperca chuatsi FST sequence, with which it also has the closest evolutionary relationship according to a phylogenetic study. Omnipresent distribution of RbFST transcripts were detected in the gill, liver, spleen, head kidney, kidney, skin, muscle, heart, brain, and intestine of healthy animals, with significantly higher expression levels in the heart, followed by the liver tissue. Under pathogenic stress caused by two bacterial pathogens, Streptococcus iniae and Edwardsiella tarda, RbFST transcription was found to be significantly up-regulated. Altogether, our findings suggest the putative role of RbFST in immune related responses against pathogenic infections, further prefiguring its significance in rock bream physiology.