• Journal of Environmental Health Sciences
• /
• v.45 no.6
• /
• pp.613-621
• /
• 2019

Objectives: This study was performed to examine the relationship between health behaviors, living environment, and asthma in adolescents in Korea. Methods: Information on adolescents' characteristics, including demographic factors, health behaviors, and doctor's diagnosis of asthma was obtained from the Korean Youth Risk Behavior Web-based Survey (2015). In total, 68,043 middle and high school students participated. Environmental characteristics, including city park area and outdoor PM₁₀ concentrations in 2015 were obtained from the Korean Statistical Information Service. The adolescents' and environmental characteristics were merged by local information. Multiple logistic regression models were used to investigate the risk factors affecting asthma in adolescents. Results: The prevalence of asthma in adolescents in 2015 was 8.8%. In the multiple logistic regression analysis, adolescents who were male, attended middle school, suffered obesity, experienced tobacco smoking, had physical activity levels of 2 to 4 days, had higher stress levels, and lived in areas with outdoor PM₁₀ concentrations more than 47 ㎍/㎥ were more likely to have asthma, while adolescents who had middle levels of family economic status were less likely to do so. Conclusions: The fact that PM₁₀ concentration can affect asthma is an important point in this study. Risk factors identified in this study could be used as basic data for the prevention and management of asthma in Korea.

• The Korean Journal of Physiology and Pharmacology
• /
• v.7 no.6
• /
• pp.325-331
• /
• 2003

3-Nitropropionic acid (3-NP) inhibits electron transport in mitochondria, leading to a metabolic failure. In order to elucidate the mechanism underlying this toxicity, we examined a few biochemical changes possibly involved in the process, such as metabolic inhibition, generation of reactive oxygen species (ROS), DNA strand breakage, and activation of Poly(ADP-ribose) polymerase (PARP). Exposure of SK-N-BE(2)C neuroblastoma cells to 3-NP for 48 h caused actual cell death, while inhibition of mitochondrial function was readily observed when exposed for 24 h to low concentrations (0.2${\sim}$2 mM) of 3-NP. The earliest biochemical change detected with low concentration of 3-NP was an accumulation of ROS (4 h after 3-NP exposure) followed by degradation of DNA. PARP activation by damaged DNA was also detectable, but at a later time. The accumulation of ROS and DNA strand breakage were suppressed by the addition of glutathione or N-acetyl-L-cysteine (NAC), which also partially restored mitochondrial function and cell viability. In addition, inhibition of PARP also reduced the 3-NP-induced DNA strand breakage and cytotoxicity. These results suggest that oxidative stress and activation of PARP are the major factors in 3-NP-induced cytotoxicity, and that the inhibition of these factors may be useful in protecting neuroblastoma cells from 3-NP-induced toxicity.

• Communications of Mathematical Education
• /
• v.24 no.3
• /
• pp.563-585
• /
• 2010

The major goals of this study are to find the factors that enhance self-directed math learning in college math classes and to provide the students with the opportunities to check and develop their self-directed math learning attitude. For these research goals, we prepared the questionnaires that asked about their learning motivations, basic learning ability, self-discipline strategies, and self-directed learning strategies. Another purpose of the questionnaires was to give them the chances to check and improve their attitude toward those learning strategies, motivation and ability. From the research results, we find that the important factors for self-directed learning are internal & external motivations, concentration ability, and the goal-setting and plan-making abilities. In addition, concentration ability, good habit, stress-control, recognition of math value, and self-directing ability are found to be necessary for the desirable learning environment. On the other hand, we find that the ability to perform note-taking, class preparation and review, time-control, and test-control is required for the selection and practice of self-fitting learning strategies. Finally, we provided our own self-directed math learning model. Our model, containing the necessary factors for self-directed math learning, is the revised and modified one of Knowles(1975)'s 5 stage self-directed learning model that comprises diagnosis of learning desire, setting learning goals, grasping human&material resources, selection and practice of proper learning strategies, and evaluation of learning results.

• The Korean Journal of Physiology and Pharmacology
• /
• v.22 no.5
• /
• pp.467-479
• /
• 2018

The aging process induces a plethora of changes in the body including alterations in hormonal regulation and metabolism in various organs including the heart. Aging is associated with marked increase in the vulnerability of the heart to ischemia-reperfusion injury. Furthermore, it significantly hampers the development of adaptive response to various forms of conditioning stimuli (pre/post/remote conditioning). Aging significantly impairs the activation of signaling pathways that mediate preconditioning-induced cardioprotection. It possibly impairs the uptake and release of adenosine, decreases the number of adenosine transporter sites and down-regulates the transcription of adenosine receptors in the myocardium to attenuate adenosine-mediated cardioprotection. Furthermore, aging decreases the expression of peroxisome proliferator-activated receptor gamma co-activator 1-alpha ($PGC-1{\alpha}$) and subsequent transcription of catalase enzyme which subsequently increases the oxidative stress and decreases the responsiveness to preconditioning stimuli in the senescent diabetic hearts. In addition, in the aged rat hearts, the conditioning stimulus fails to phosphorylate Akt kinase that is required for mediating cardioprotective signaling in the heart. Moreover, aging increases the concentration of $Na^+$ and $K^+$, connexin expression and caveolin abundance in the myocardium and increases the susceptibility to ischemia-reperfusion injury. In addition, aging also reduces the responsiveness to conditioning stimuli possibly due to reduced kinase signaling and reduced STAT-3 phosphorylation. However, aging is associated with an increase in MKP-1 phosphorylation, which dephosphorylates (deactivates) mitogen activated protein kinase that is involved in cardioprotective signaling. The present review describes aging as one of the major confounding factors in attenuating remote ischemic preconditioning-induced cardioprotection along with the possible mechanisms.

• Geomechanics and Engineering
• /
• v.27 no.5
• /
• pp.497-509
• /
• 2021

A large deformation FEM (Finite Element Method) based numerical analysis has been performed to study the behaviour of the bell-shaped anchor embedded in undrained saturated (cohesive) soil with the help of finite element based software ABAQUS. A typical model anchor with bell-diameter of 0.125 m, embedded in undrained saturated soil with varying cohesive strength (from 5 kN/m² to 200 kN/m²) has been chosen for studying the characteristic behaviour of the bell-shaped anchor installed in cohesive soil. Breakout factors have been evaluated for each case and verified with the results of experimental model tests for three different types of soil samples. The maximum value of breakout factor was found as about 8.5 within a range of critical embedment ratio of 2.5 to 3. An explicit model has been developed to estimate the breakout factor (F_c) for uplift capacity of bell-shaped anchor within clay mass in terms of H/D ratio (embedment ratio). It was also found that, the ultimate uplift capacity of the anchor increases with the increase of the value of cohesive strength of the soil and H/D ratio. The empirical equation developed in the present investigation is usable within the range of cohesion value and H/D ratio from 5 kN/m² to 200 kN /m² and 0.5 to 3.0 respectively. The proposed model has been validated against data obtained from a series of model tests carried out in the present investigation. From the stress-profile analysis of the soil mass surrounding the anchor, occurrence of stress concentration is found to be generated at the joint of anchor shaft and bell. It was also found that the vertical and horizontal stresses surrounding the anchor diminish at about a distance of 0.3 m and 0.15 m respectively.

• Journal of Environmental Science International
• /
• v.33 no.4
• /
• pp.279-282
• /
• 2024

This study aimed to verify the results of emotional analysis with respect to canine behavior as reported in the existing animal behavior field based on the dog vestibular emotional reflex (VER) principle, and to evaluate humans and animals based on empathy gained through true communication rather than human-centered interpretation. A total of 200 canines were divided into non-daily and daily situation groups (n=100 each). To assess the psychological and emotional state of each group, these changes were applied to the principle of VER, and six measurement values were selected: positive emotion (balance and energy), negative emotion (tension/anxiety and stress), and body condition (inhibition and neuroticism). The results showed a statistically significant difference (p<0.05) in positive emotions, negative emotions, and body conditions between the two groups. In addition, balance, energy, tension/anxiety, inhibition, and neuroticism were higher in the non-daily situation group than in the daily situation group, with an exception for stress. Compared with the canine daily situation groups, canine in the non-daily situation groups instinctively observed their surroundings to cope with possible threats, had decreased concentration, and elevated vitals due to high-intensity anxiety. This can be perceived as a state of immediate reaction to possible situations/threats. In conclusion, it was confirmed through Vibra Image technology that canine instability mainly affects three factors: positive emotion, negative emotion, and physical condition.

• The Journal of the Convergence on Culture Technology
• /
• v.7 no.4
• /
• pp.785-789
• /
• 2021

Paprika productivity is different even in the same quality greenhouse and in the same region. These differences are known to due to differences in various environmental factors. This study was conducted to investigate the difference in the level of various environmental factors between high-productivity (HPF) and low-productivity (LPF) greenhouses. The largest difference between the two greenhouses in the daily or weekly average values of major environmental factors was the CO₂ concentration, but the LPF was higher than the HPF, so it was not determined as a factor for the difference in productivity. Correlation analysis among 14 environmental factors showed a high correlation among irradiation or related factors in moisture. The regression coefficients of the linear regression model between vapor pressure deficit and relative humidity were -0.0202kpa in HPF and -0.0262kpa in LPF. In particular, in February and March, the vapor pressure deficit in LPF was 1.5kpa or more, and the cumulative vapor pressure deficit compared to the cumulative irradiation at the early period of cultivation increased rapidly. The reason for the low productivity in LPF is thought to be that the plant was affected by moisture stress due to high vapor pressure deficit and transpiration under low irradiation conditions in the early period of cultivation and in winter.

• Korean Journal of Child Studies
• /
• v.37 no.3
• /
• pp.1-12
• /
• 2016

Objective: This study aimed to examine the difference in toddlers' accumulated cortisol levels based on childcare experience in toddlerhood and the relationship between temperament and accumulated cortisol levels. Methods: Hair sample were collected for measure accumulated cortisol level in 87 toddlers. The Early Childhood Behavior Questionnaire (ECBQ) was used to measure temperament. Results: First, toddlers in childcare showed higher accumulated cortisol levels than in-home toddlers. Second, toddlers in childcare, exhibited a significant correlation between accumulated cortisol levels and surgency. Third, the accumulated cortisol levels of in-home toddlers exhibited a significant correlation with negative affect. In this research, there was significant range in the accumulated cortisol level according to childcare use, and the factors related to accumulated cortisol levels were different in each context. Conclusion: The results of this research support the "susceptibility to context of HPA axis" and imply a needed discussion about the effect of childcare experiences in toddlerhood.

• Proceedings of the KSME Conference
• /
• 2008.11a
• /
• pp.1355-1360
• /
• 2008

Stainless steel sheets are widely used as the structure material for the railroad cars and the commercial vehicles. These kinds structures used stainless steel sheets are commonly fabricated by using the gas welding. Gas welding is very important and useful technology in fabrication of an railroad car and vehicles structure. However fatigue strength of the gas welded joints is considerably lower than parent metal due to stress concentration at the weldment, fatigue strength evaluation of gas welded joints are very important to evaluate the reliability and durability of railroad cars and to establish a criterion of long life fatigue design. In this paper, ${\Delta}P-N_f$ curve were obtained by fatigue tests. Using these results, the accelerated life test (ALT) is conducted. From the experimental results, an acceleration model is derived and acceleration factors are estimated. So it is intended to obtain the useful information for the fatigue lifetime of plug and ring gas welded joints and data analysis by statistic reliability method, to save time and cost, and to develop optimum accelerated life prediction plans.

• Journal of Korea Multimedia Society
• /
• v.23 no.2
• /
• pp.146-154
• /
• 2020

Negative emotion causes stress and lack of attention concentration. The classification of negative emotion is important to recognize risk factors. To classify emotion status, various methods such as questionnaires and interview are used and it could be changed by personal thinking. To solve the problem, we acquire multi modal bio-signals such as electrocardiogram (ECG), skin temperature (ST), galvanic skin response (GSR) and extract features. The neural network (NN), the deep neural network (DNN), and the deep belief network (DBN) is designed using the multi modal bio-signals to analyze emotion status. As a result, the DBN based on features extracted from ECG, ST and GSR shows the highest accuracy (93.8%). It is 5.7% higher than compared to the NN and 1.4% higher than compared to the DNN. It shows 12.2% higher accuracy than using only single bio-signal (GSR). The multi modal bio-signal acquisition and the deep learning classifier play an important role to classify emotion.