• Steel and Composite Structures
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• 제45권3호
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• pp.305-330
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• 2022

This article aims to investigate the static deflection and stress analysis of bi-directional functionally graded porous plate (BDFGPP) modeled by unified higher order kinematic theories to include the shear stress effects, which not be considered before. Different shear functions are described according to higher order models that satisfy the zero-shear influence at the top and bottom surfaces, and hence refrain from the need of shear correction factor. The material properties are graded through two spatial directions (i.e., thickness and length directions) according to the power law distribution. The porosities and voids inside the material constituent are described by different cosine functions. Hamilton's principle is implemented to derive the governing equilibrium equation of bi-directional FG porous plate structures. An efficient numerical differential integral quadrature method (DIQM) is exploited to solve the coupled variable coefficients partial differential equations of equilibrium. Problem validation and verification have been proven with previous prestigious work. Numerical results are illustrated to present the significant impacts of kinematic shear relations, gradation indices through thickness and length, porosity type, and boundary conditions on the static deflection and stress distribution of BDFGP plate. The proposed model is efficient in design and analysis of many applications used in nuclear, mechanical, aerospace, naval, dental, and medical fields.

• Asian-Australasian Journal of Animal Sciences
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• 제13권9호
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• pp.1210-1218
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• 2000

Four experiments were conducted to evaluate the effect of temperature and humidity on biochemical indices of Arbor Acres broilers at different weeks of age. The alkaline phosphatase (AKP), acid phosphatase (ACP), lactic dehydrogenase (LD), creatine kinase (CK), plasma glucose (Glu), calcium (Ca), potassium (K), chloride (Cl), urea nitrogen (UN), uric acid (UA), plasma thyroxin (T4), triiodothyronine (T3) and insulin levels were determined in all the four experiments. In experiment 1, the plasma Glu, LD and CK levels were increased by heat exposure ($35{^{\circ}C}$ and 35, 60, or 85% RH, 2 h) and this effect was aggravated by longer exposure (24 h). No significant changes (p>0.05) were found in Ca concentration, activity of AKP and ACP. In experiment 2, temperature (10, 20, 30, $33{^{\circ}C}$) had significant effect on the levels of K, Cl, UN, UA levels and the activity of LD (p<0.01), but had no significant influence on the activity of CK (p>0.05). The UN, UK and LD levels were elevated by low temperature $(10{^{\circ}C})$ (p<0.01), Cl content was increased by high temperature ($(33{^{\circ}C})$ (p<0.01), and K level was decreased by high ($(33{^{\circ}C})$ or low $(10{^{\circ}C})$ temperature and increased by medium temperature $(30{^{\circ}C})$ (p<0.01). The humidity (35, 85% RH) only had significant effect on Cl concentration which was decreased by high humidity (p<0.01). In experiment 3, the result showed that only the LD and CK activity were significantly increased (p<0.01) by high temperature (7, 24, 28, $32{^{\circ}C}$) or high humidity (35, 85% RH). Temperature and humidity had no significant effect on K, Cl, UA, UN and Glu levels (p>0.05). In experiment 4 (24, 27, 30, $33{^{\circ}C}$; 30, 45, 60, 75, 90% RH), plasma T3 level was declined by high temperature $(33{^{\circ}C})$, and this phenomena disappeared in birds under high temperature and high humidity environment. T4 concentration in plasma was not affected by temperature (p>0.05), but was increased by high or low humidity (p<0.01). Neither temperature nor humidity had significant effect on plasma insulin concentration (p>0.05). The results of the four experiments suggested that broilers at different growth periods might have different thermal requirements and would response differently to heat exposure. The plasma biochemical indices themselves had big variation; the reaction of the indices to thermal exposure treatment differed with the age of broilers. The big variation of biochemical indices themselves might cover the response of indices to temperature and humidity treatments.

• 한국치위생학회지
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• 제12권3호
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• pp.471-483
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• 2012

Objectives : This study looked at the relationship between occupational stress and the Oral Health Impact Profile (OHIP), to evaluate the effect of occupational stress-related factors. Methods : Data was obtained from a cross-sectional survey of 260 local officials in Gangwondo. The research comprised three questions relating to subjective oral symptoms, an occupational stress measurement tool and an oral health impact factor which was composed of questions. The data was analysed using t-test, one-way ANOVA, Pearson correlation and path analysis in Amos. Results : Occupational stress had a positive correlation to drinking frequency, Oral symptoms had a negative correlation. And drinking frequency, smoking amount and occupational stress had a positive correlation to oral symptoms. It denoted that drinking frequency, occupational stress and oral symptoms had a negative correlation to OHIP. The path model had an excellent goodness of fit (p=0.07, namely p>0.05). Five 'goodness-of-fit indices' of the model were all above 0.9: GFI=0.987, AGFI=0.952, NFI=0.902, IFI=0.939, CFI=0.934), and its RMSEA was 0.045. Occupational stress and oral symptoms had a firsthand impact on OHIP. In addition, it affected OHIP through the parameters of oral symptoms. Occupational stress exercised a firsthand influence on drinking frequency, drinking frequency exercised a firsthand influence on smoking amount. Smoking amount had a firsthand impact on oral symptoms. Conclusions: Oral health education programs for the development of an improved oral hygiene environment through reduction in drinking and smoking also need to focus on relieving stress by improving workplace culture. In addition, due to good communication is required to reduce occupational stress caused by interpersonal conflict.

• Asian-Australasian Journal of Animal Sciences
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• 제30권4호
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• pp.593-601
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• 2017

Objective: The aim of this study was to evaluate heat tolerance using heat tolerance indices, physiological, physical, thermographic, and hematological parameters in Santa Ines and Morada Nova sheep breeds in the Federal District, Brazil. Methods: Twenty-six adult hair sheep, one and a half years old, from two genetic groups (Santa Ines: 12 males and 4 females; Morada Nova: 7 males and 3 females) were used and data (rectal temperature, respiratory rate, heart rate, skin temperatures; hematological parameters) were collected during three consecutive days, twice a day (morning and afternoon), with a total of six repetitions. Also physical parameters (biometric measurements, skin and hair traits) and heat tolerance indices (temperature-humidity index, Iberia and Benezra) were evaluated. The analyses included analyses of variance, correlation, and principal components with a significance level of 5%. Results: The environmental indices, in general, indicate a situation of thermal discomfort for the animals during the afternoon. Breed significantly influenced (p<0.001) physiological and physical characteristics of skin, hair, biometric measurements and Iberia and Benezra heat tolerance indices. Santa Ines animals were bigger and had longer, greater number and darker hair, thicker skin, greater respiratory rate and Benezra index and lower Iberia index compared with Morada Nova breed. Conclusion: Although both breeds can be considered adapted to the environmental conditions of the region, Morada Nova breed is most suitable for farming in the Midwest region. The positive correlation found between the thermographic temperatures and physiological parameters indicates that this technique can be used to evaluate thermal comfort. Also, it has the advantage that animals do not have to be handled, which favors animal welfare.

• Journal of Ginseng Research
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• 제44권1호
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• pp.79-85
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• 2020

Background: Helicobacter pylori increases reactive oxygen species (ROS) and induces oxidative DNA damage and apoptosis in gastric epithelial cells. DNA damage activates DNA damage response (DDR) which includes ataxia-telangiectasia-mutated (ATM) activation. ATM increases alternative reading frame (ARF) but decreases mouse double minute 2 (Mdm2). Because p53 interacts with Mdm2, H. pylori-induced loss of Mdm2 stabilizes p53 and induces apoptosis. Previous study showed that Korean Red Ginseng extract (KRG) reduces ROS and prevents cell death in H. pylori-infected gastric epithelial cells. Methods: We determined whether KRG inhibits apoptosis by suppressing DDRs and apoptotic indices in H. pylori-infected gastric epithelial AGS cells. The infected cells were treated with or without KRG or an ATM kinase inhibitor KU-55933. ROS levels, apoptotic indices (cell death, DNA fragmentation, Bax/Bcl-2 ratio, caspase-3 activity) and DDRs (activation and levels of ATM, checkpoint kinase 2, Mdm2, ARF, and p53) were determined. Results: H. pylori induced apoptosis by increasing apoptotic indices and ROS levels. H. pylori activated DDRs (increased p-ATM, p-checkpoint kinase 2, ARF, p-p53, and p53, but decreased Mdm2) in gastric epithelial cells. KRG reduced ROS and inhibited increase in apoptotic indices and DDRs in H. pylori-infected gastric epithelial cells. KU-55933 suppressed DDRs and apoptosis in H. pylori-infected gastric epithelial cells, similar to KRG. Conclusion: KRG suppressed ATM-mediated DDRs and apoptosis by reducing ROS in H. pylori-infected gastric epithelial cells. Supplementation with KRG may prevent the oxidative stress-mediated gastric impairment associated with H. pylori infection.

• 핵의학기술
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• 제18권2호
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• pp.78-82
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• 2014

일상생활에서 경험하는 다양한 사건들은 모두 스트레스인자로 작용하여 이에 대한 대처가 부적절하면 인체의 항상성이 파괴되어 정신 및 신체질환의 발생에 영향을 주며 인체의 면역반응에 부정적인 영향을 주어 질병에 대한 대처능력을 떨어뜨려 다양한 만성질환에 대한 감수성을 높일 수 있다. 스트레스에서 내분비학적 및 생화학적 반응을 이용하는 근거는 신체 대부분의 시스템이 스트레스 중 변화하고 이런 변화를 나타내는 생물학적 지표가 스트레스와 관련된다는 근거에 의해 신체적 반응에 대한 생화학적 반응으로서 스트레스 호르몬인 코티졸 측정과 생리적인 스트레스반응으로서 여러 가지의 생리신호 중에 혈압(blood pressure)과 심박변이도(heart rate variability, HRV)를 측정하여 스트레스 반응 수준을 측정하여 상관관계를 분석하였다. 전체 94명의 피실험 대상자의 혈청 코티졸의 농도는 평균 11.22 ng/mL 이었고 최저 3.6ng/mL에서 최고 23.3 ng/mL의 분포를 나타냈다. 남녀 집단을 나누어 분석하면 남자가 13.71 ng/mL 으로 여자 10.47 ng/mL 보다 유의하게 높았다(p<0.05). 생리신호 중 혈압을 남녀 집단으로 구분하여 분석한 결과 수축기혈압 평균이 남자가 133 mmHg으로 여자 117 mmHg보다 통계적으로 유의하게 높았다(p<0.05).확장기 혈압의 평균은 남자가 81mmHg로 여자의 76.4 mmHg 보다 높았으나 유의하지 않았다. 심박변이도 중 교감신경 활동을 보여주는 LF/HF ratio 비도 남자가 3.09 로 여자 1.77 보다 유의하게 높게 나타났다(p<0.05).

• Child Health Nursing Research
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• 제23권3호
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• pp.279-291
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• 2017

Purpose: The aim of this study was to explore how characteristics of ADHD children affect social support for mothers, parenting stress, parenting sense of competence, coping, and quality of life. The conceptual model was based on the Lazarus and Folkman's stress-evaluation-coping theory. Methods: Data were collected 208 mothers of children with ADHD. Data were analysed using SPSS 18.0 and AMOS 18.0 programs. Results: The proposed model was good fit for the data based on the model fit indices. Parenting stress, parenting sense of competence and coping directly affected quality of life but characteristics of the children and social support had only an indirect effect. The explanatory power of these variables was 52.1%. Conclusion: The results of this study indicate that nursing strategies to increase social support for mothers with ADHD children, lowers parenting stress, improves parenting sense of competence, and guides the parents to choose appropriate coping. In particular, as social support has the strongest influence on the quality of life, it is necessary to develop nursing intervention programs that utilize social support for parents with ADHD children.

• 여성건강간호학회지
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• 제15권3호
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• pp.231-241
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• 2009

Purpose: This study was designed to construct and test a structural equation model for life satisfaction in grandmothers who were parenting grandchildren Methods: Grandmothers assuming part-time parenting responsibilities for grandchildren were recruited in four cities in South Korea. They were asked to complete a questionnaire through face to face interviews or self reports, and 248 data units were analyzed with Structural Equation Modeling. Results: Model fit indices for the final model revealed a fit at an excellent level, and all of the 12 paths were statistically significant explaining 51% of the variance. Predictors of life satisfaction in the final model were parenting efficacy, perceived health status, parenting stress, amount of parenting, and demographic factors. The new findings of this study were as follows: First, the satisfaction with life of part-time parenting grandmothers was less than that of non-parenting grandmothers. Second, parenting stress and parenting efficacy revealed determinants to life satisfaction. Third, motivation of parenting and amount of parenting affect both parenting stress and parenting efficacy. Conclusion: The value of parenting and the grandmother-adult children relationship quality should also be considered in developing a grandmothers' educational program, because these are the factors which strengthen parenting efficacy and alleviate parenting stress.

• 한국지반공학회:학술대회논문집
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• 한국지반공학회 2010년도 추계 학술발표회
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• pp.241-252
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• 2010

This study investigates the application of dilatometer test for evaluating the deformation characteristics of granular soil. $K_D$ is the most sensitive to the stress history among CPT and DMT measurements, and $E_D$ and $q_c$ are observed to be similarly affected by the stress history. The coefficient of at-rest earth pressure($K_0$) is an indirect measure evaluating the stress history of granular soil. A relation using only DMT indices provides appropriate prediction of $K_0$ values. Although penetration of dilatometer inevitably induces the failure of cementation bonds, $E_D$ reflects the deformation characteristics of undamaged cementation relatively well. Therefore, a slightly better prediction of M value for cemented sand is achieved by using $E_D$ rather than $q_c$. Because of the weaker particle strength of calcareous sand compared than quartz sand, the majority of sand particles adjacent to dilatometer probe will be crushed during penetration. The particle crushing will induce the less contraction of the dilatometer membrane during penetration, consequently, the smaller $K_D$ and $E_D$ of calcareous sand.

• 한국초전도ㆍ저온공학회논문지
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• 제15권4호
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• pp.10-14
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• 2013

We have clearly investigated with respect to the survival of the insulator at cryogenic temperature under the electrical stress. The breakdown and voltage-time characteristics of turn-to-turn models for point contact geometry and surface contact geometry using copper multi wrapped with polyimide film for an HTS transformer were investigated under AC and impulse voltage at 77 K. Polyimide film (Kapton) 0.025 mm thick is used for multi wrapping of the electrode. As expected, the breakdown voltages for the surface contact geometry are lower than that of the point contact geometry, because the contact area of the surface contact geometry is lager than that of the point contact geometry. The time to breakdown t50 decreases as the applied voltage is increased, and the lifetime indices increase slightly as the number of layers is increased. The electric field amplitude at the position where breakdown occurs is about 80 % of the maximum electric field value. The relationship between survival probability and the electrical stress at cryogenic temperature was evident.