• Advances in nano research
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• 제13권2호
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• pp.121-134
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• 2022

Emerge of nanotechnology impacts all aspects of humans' life. One of important aspects of the nanotechnology and nanoparticles (NPs) is in the food production industry. The safety of such foods is not well recognized and producing safe foods using nanoparticles involves delicate experiments. In this study, we aim to incorporate intelligent computer simulation in predicting safety degree of nanofoods. In this regard, the safety concerns on the nano-foods are addressed considering cytotoxicity levels in metal oxides nanoparticles using adaptive neuro-fuzzy inference system (ANFIS) and response surface method (RSM). Three descriptors including chemical bond length, lattice energy and enthalpy of formation gaseous cation of 15 selected NPs are examined to find their influence on the cytotoxicity of NPs. The most effective descriptor is selected using RSM method and dependency of the toxicity of these NPs on the descriptors are presented in 2D and 3D graphs obtained using ANFIS technique. A comprehensive parameters study is conducted to observe effects of different descriptors on cytotoxicity of NPs. The results indicated that combinations of descriptors have the most effects on the cytotoxicity.

• Journal of Powder Materials
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• 제31권1호
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• pp.57-76
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• 2024

Recent advancements in electronic devices and wireless communication technologies, particularly the rise of 5G, have raised concerns about the escalating electromagnetic pollution and its potential adverse impacts on human health and electronics. As a result, the demand for effective electromagnetic interference (EMI) shielding materials has grown significantly. Traditional materials face limitations in providing optimal solutions owing to inadequacy and low performance due to small thickness. MXene-based composite materials have emerged as promising candidates in this context owing to their exceptional electrical properties, high conductivity, and superior EMI shielding efficiency across a broad frequency range. This review examines the recent developments and advantages of MXene-based composite materials in EMI shielding applications, emphasizing their potential to address the challenges posed by electromagnetic pollution and to foster advancements in modern electronics systems and vital technologies.

• Journal of the Korean Society of Industry Convergence
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• 제27권4_2호
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• pp.1001-1007
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• 2024

Recent deep learning algorithms for object detection in real-time play a crucial role in various applications such as autonomous driving, traffic monitoring, health care, and water quality monitoring. The size of small objects, in particular, significantly impacts the accuracy of detection models. However, data containing small objects can lead to underfitting issues in models. Therefore, this study developed a deep learning model capable of quickly detecting small objects to provide more accurate predictions. The RE-SOD (Residual block based Small Object Detector) developed in this research enhances the detection performance for small objects by using RGB separation preprocessing and residual blocks. The model achieved an accuracy of 1.0 in image classification and an mAP50-95 score of 0.944 in object detection. The performance of this model was validated by comparing it with real-time detection models such as YOLOv5, YOLOv7, and YOLOv8.

• Journal of the Korean Magnetic Resonance Society
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• 제28권3호
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• pp.25-31
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• 2024

Toxins produced by marine toxigenic algae have garnered growing attention due to their detrimental impacts on marine ecosystem, aquaculture, and human health. Among these, diarrhetic shellfish poisoning (DSP) toxins, such as okadaic acid (OA), are of particular concern. In this study, we report the successful isolation and structural elucidation of three new derivatives of OA from the marine dinoflagellate Prorocentrum lima. These newly identified compounds, OA-2Me-C7, OA-2-Me-C8, and OA-1-Me-C8, were characterized through a comprehensive series of NMR experiments, combined with structural comparisons to the well-known OA. The identification of these derivatives contributes to the expanding knowledge of DSP toxin diversity and provides new insights into the structural variations of these harmful algal toxins.

• Atmosphere
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• 제25권4호
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• pp.639-657
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• 2015

There is an increasing need to improve the air quality over South Korea to protect public health from local and remote anthropogenic pollutant emissions that are in an increasing trend. Here, we evaluate the performance of the WRF-Chem (Weather Research and Forecasting-Chemistry) model in simulating near-surface air quality of major Korean cities, and investigate the impacts of time-varying chemical initial and lateral boundary conditions (IC/BCs) on the air quality simulation using a chemical downscaling technique. The model domain was configured over the East Asian region and anthropogenic MICS-Asia 2010 emissions and biogenic MEGAN-2 emissions were applied with RACM gaseous chemistry and MADE/SORGAM aerosol mechanism. Two simulations were conducted for a 30-days period on April 2010 with chemical IC/BCs from the WRF-Chem default chemical species profiles ('WRF experiment') and the MOZART-4 (Model for OZone And Related chemical Tracers version 4) ('WRF_MOZART experiment'), respectively. The WRF_MOZART experiment has showed a better performance to predict near-surface CO, $NO_2$, $SO_2$, and $O_3$ mixing ratios at 7 major Korean cities than the WRF experiment, showing lower mean bias error (MBE) and higher index of agreement (IOA). The quantitative impacts of the chemical IC/BCs have depended on atmospheric residence time of the pollutants as well as the relative difference of chemical mixing ratios between the WRF and WRF_MOZART experiments at the lateral boundaries. Specifically, the WRF_MOZART experiment has reduced MBE in CO and O3 mixing ratios by 60~80 ppb and 5~10 ppb over South Korea than those in the WRF-Chem default simulation, while it has a marginal impact on $NO_2$ and $SO_2$ mixing ratios. Without using MOZART-4 chemical IC, the WRF simulation has required approximately 6-days chemical spin-up time for the East Asian model domain. Overall, the results indicate that realistic chemical IC/BCs are prerequisite in the WRF-Chem simulation to improve a forecast skill of local air quality over South Korea, even in case the model domain is sufficiently large to represent anthropogenic emissions from China, Japan, and South Korea.

• Journal of Korea Entertainment Industry Association
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• 제14권7호
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• pp.609-621
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• 2020

This study identified the impacts of organizational commitment on medical service reduction rates by lifestyles of medical institution workers with a medium of environmental factors in a medical institution, and it conducted a survey targeting 300 medical institution workers in Jeolla-do, South Korea. The results are as follows. First, there was a significant difference in an organizational commitment by sociodemographic characteristics based on age, academic career, gender, marital status, occupational description, monthly earnings, the years of employment, and the type of hospital. Second, there was a significant difference in environmental factors by sociodemographic characteristics based on marital status, the years of employment, and the type of hospital. Third, there was a significant difference in the inpatient reduction rate based on the occupational description, years of employment, and the type of hospital. In the outpatient reduction rate, a significant difference was shown based on age, marital status, occupational description, the years of employment, and the type of hospital. Fourth, when analyzing the relationship between organizational commitment, environmental factors, and the reduction rate, there was a significant positive correlation between inpatient reduction rate and outpatient reduction rate. Fifth, when analyzing the impacts on the inpatient reduction rate by deploying organizational commitment and environmental factors at the same time, it was shown that the environmental factors mediated partially in organizational commitment and inpatient reduction rate. In the case of outpatient reduction rate, it was shown that the environmental factors mediated completely in organizational commitment and outpatient reduction rate. The present study is aimed to contribute to providing the baseline data for an efficient operational plan and effective workforce management of medical institutions.

• Health Policy and Management
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• 제27권2호
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• pp.167-176
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• 2017

Background: This study aimed to analyze the impact of community health care resources on the place of death of older adults with dementia compared to those with cancer in South Korea, using public administrative big data. Methods: Based on a literature review, we selected person- and community-level variables that can affect older people's decisions about where to die. Data on place-of-death and person-level attributes were obtained from the 2013 death certification micro data from Statistics Korea. Data on the population and economic and health care resources in the community where the older deceased resided were obtained from various open public administrative big data including databases on the local tax and resident population statistics, health care resources and infrastructure statistics, and long-term care (LTC) insurance statistics. Community-level data were linked to the death certificate micro data through the town (si-gun-gu) code of the residence of the deceased. Multi-level logistic regression models were used to simultaneously estimate the impacts of community as well as individual-level factors on the place of death. Results: In both the dementia (76.1%) and cancer (87.1%) decedent groups, most older people died in the hospital. Among the older deceased with dementia, hospital death was less likely to occur when the older person resided in a community with a higher supply of LTC facility beds, but hospital death was more likely to occur in communities with a higher supply of LTC hospital beds. Similarly, among the cancer group, the likelihood of a hospital death was significantly lower in communities with a higher supply of LTC facility beds, but was higher in communities with a higher supply of acute care hospital beds. As for individual-level factors, being female and having no spouse were associated with the likelihood of hospital death among older people with dementia. Conclusion: More than three in four older people with dementia die in the hospital, while home is reported to be the place of death preferred by Koreans. To decrease this gap, an increase in the supply of end-of-life (EOL) care at home and in community-based service settings is necessary. EOL care should also be incorporated as an essential part of LTC. Changes in the perception of EOL care by older people and their families are also critical in their decisions about the place of death, and should be supported by public education and other related non-medical, social approaches.

• Korean Journal of Environmental Biology
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• 제23권2호
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• pp.146-151
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• 2005

Recent studies indicated the utility of whole effluent assessment as a measure to control discharge of toxic effluents to receiving water in Korea. However, most studies have been focussed on acute lethal effects of toxic wastewater with little consideration of chronic sublethal impacts which are of growing concern in protecting aquatic ecosystem. We conducted acute and chronic toxicity tests with effluents discharged from five different dyeing plants in Gyeong-gi province using a marine bacterium Vibrio fischeri and a freshwater macroinvertebrate Daphnia magna to demonstrate the importance of assessing chronic sublethal effects. Various levels of acute and chronic toxicities were observed in many samples tested in this study. In 21-d chronic toxicity tests using D. magna all samples showed effects on reproduction and growth. Notable mortalities were also noted in three out of five effluents. The result of the Microtox assay indicated that acute microbial toxicity existed in effluents from two out of five plants and acute daphnid toxicity was observed in only one effluent. The result of this study clearly suggests chronic toxicity tests are more suitable to assess biological effects of effluents because it was shown from this study that even an effluent with no acute toxicity could cause chronically lethal and/or sublethal adverse effects on aquatic biota which may affect the population dynamics in aquatic ecosystem.

• Journal of agricultural medicine and community health
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• 제42권2호
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• pp.69-78
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• 2017

Objectives: This study investigated whether the impacts of orthodontic treatment of malocclusion on oral health-related quality of life and happiness are positive with middle and high school students Methods: Subjects were 157 orthodontic patients and 83 non-orthodontic in malocclusion patients. Questionnaires were collected with the self-administered method, and consisted of the general characteristics, self-esteem, social support appraisal scale(friends, family, teacher), Oral Impact on Daily Performance (OIDP) and oxford happiness questionnaire (OHQ). Results: A physical factor was lower in the orthodontic treatment group ($5.8{\pm}2.48$) than in the non-orthodontic treatment group ($7.7{\pm}2.10$)(p<0.001), and OIDP was lower in the orthodontic treatment group ($7.0{\pm}1.79$) than in the non-orthodontic treatment group ($7.8{\pm}1.80$)(p=0.002). A feeling of happiness was higher in the orthodontic treatment group($4.6{\pm}0.81$) than in the orthodontic treatment group ($4.3{\pm}0.89$) (p=0.009). As results of multiple regression analysis, OIDP was affected of orthodontic treatment(${\beta}=-0.0222$, p=0.001) and OHP was affected of orthodontic treatment(${\beta}=0.087$, p=0.030) and OIDP(${\beta}=0.116$, p=0.003). Conclusions: Orthodontic treatment of malocclusion may positively affects happiness in teenager. Support policy for orthodontic treatment of malocclusion is necessary for adolescents.

• Journal of Environmental Health Sciences
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• 제39권1호
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• pp.90-98
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• 2013

Objectives: Many studies have shown that air pollution and temperature have adverse effects on mortality and morbidity. But the interactive effect between air pollution and temperature on mortality has been rarely investigated. This study aims to explore whether temperature modifies the associations between ambient particulate matter less than $10{\mu}m$ in diameter ($PM_{10}$) and mortality in Seoul, Korea. Methods: The time-series analysis examined the effect of the interaction between $PM_{10}$ and temperature on mortality from 1999 to 2010 in Seoul. In order to examine the interactive effect between $PM_{10}$ and temperature on mortality, we fitted a response surface model controlling the time-trends and meteorological variables. The effects of $PM_{10}$ were stratified by temperature stratum to quantitatively estimate the $PM_{10}$-health outcome associations. Results: When temperature was low (below the threshold temperature), the percentage increases per $10{\mu}g/m^3$ increase of $PM_{10}$ increased 0.38% (95% Confidence Interval[CI]: 0.09~0.68%) and 0.31% (95% CI: - 0.07~0.68%) of mortality in the all age group and ${\geq}65$ year age group, respectively. When temperature was high (above the threshold temperature), the percentage increases per $10{\mu}g/m^3$ increase of $PM_{10}$ increased 1.09% (95% CI: 0.47~1.72%) and 1.35% (95% CI: 0.65~2.06%) for mortality in the all age group and ${\geq}65$ year age group, respectively. Conclusion: The results of this study showed strong modification by temperature in the association between $PM_{10}$ and mortality. We recommend that public health strategies to minimize adverse health impact of heat and $PM_{10}$ should be considered in control and prevention measures for air pollution and weather-related health impacts.