• Journal of the Korean Society for Library and Information Science
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• 제56권4호
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• pp.357-376
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• 2022

This study examines circulation status and trends of a public library during three year periods from January 2019 to December 2021. There was a statistically significant difference in the mean number of circulation between the pre-Covid-19 period and the Covid-19 period, and the Covid-19 period and the Covid-19 recovery period. However, no significant difference was found between the pre-Covid-19 period and the Covid-19 recovery period. Across three years, there was a significant difference in the distribution of circulation per month. Circulation distribution was also significantly different among different days of the week and different hours of the day. Monthly circulation distribution and hourly circulation distribution during the pre-Covid-19 period was similar to those of the Covid-19 recovery period, whereas those of the Covid-19 period differed from the pre-Covid-19 period and the Covid-19 recovery period. It is expected that the results of this study could contribute to the collection development, and the management and improvement of services of public libraries. It is also expected that the results of this study could contribute to the prediction of circulation patterns and information needs of public library users.

• IMMUNE NETWORK
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• 제23권2호
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• pp.19.1-19.10
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• 2023

Endemic human coronaviruses (HCoVs) have been evidenced to be cross-reactive to severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). Although a correlation exists between the immunological memory to HCoVs and coronavirus disease 2019 (COVID-19) severity, there is little experimental evidence for the effects of HCoV memory on the efficacy of COVID-19 vaccines. Here, we investigated the Ag-specific immune response to COVID-19 vaccines in the presence or absence of immunological memory against HCoV spike Ags in a mouse model. Pre-existing immunity against HCoV did not affect the COVID-19 vaccine-mediated humoral response with regard to Ag-specific total IgG and neutralizing Ab levels. The specific T cell response to the COVID-19 vaccine Ag was also unaltered, regardless of pre-exposure to HCoV spike Ags. Taken together, our data suggest that COVID-19 vaccines elicit comparable immunity regardless of immunological memory to spike of endemic HCoVs in a mouse model.

• The Journal of Asian Finance, Economics and Business
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• 제8권2호
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• pp.1-13
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• 2021

Previous studies have found the significant adverse effects of coronavirus disease 2019 (COVID-19) on stock returns and volatility. The effects varied with the confirmed cases and deaths. However, the extent of the effects have never been measured exactly. This study proposes a measurement model for the COVID-19 effects. In the proposed model, stock returns in the COVID-19 period are weighted averages of pre-COVID-19 normal returns and COVID-19-induced returns. The effects are measured by the contributing weights of the COVID-19-induced returns. Kalman filtering is used to estimate the model for the world and Chinese markets, in combination with 10 markets - five most affected countries (United States, India, Brazil, Russia, and France) and five best recovering countries (Hong Kong, Australia, Singapore, Thailand, and South Korea). The sample returns are daily, obtained from the closing Morgan Stanley global investable market indexes. The full period is from September 24, 2018, to October 30, 2020, whereas the COVID-19 period is from November 18, 2019, to October 30, 2020. The contributing weights are significant and close to 100% for all markets. The COVID-19-induced returns replace the pre-COVID-19 normal returns; they are negatively auto-correlated and highly volatile. The COVID-19-induced returns are new normal returns in the COVID-19 period.

• The Korean Journal of Emergency Medical Services
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• 제24권3호
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• pp.161-169
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• 2020

Purpose: This study aims to identify changes in patients' transport time and chief complaints visiting the emergency room via emergency medical services from the "pre-COVID-19 period" compared to the "COVID-19 early-stage period". Methods: This retrospective observational study analyzed the emergency medical services reports at two time periods defined by the COVID-19 virus outbreak in Korea. The study was conducted in Busan, the Republic of Korea, from January 19 through May 6, 2019. Results: The transfer time of patients transported during the "COVID-19 early-stage period" was significantly delayed compared to the "pre-COVID-19 period" (p<.05). We found a significant increase in transport time for patients complaining of respiratory infections compared to patients without symptoms (p<.05). During the "COVID-19 early-stage period", there was a significant increase in the number of patients with respiratory infections and patients complaining of general symptoms compared to the "COVID-19early-stage period" (p<.05). Conclusion: The spread of the COVID-19 virus infection delayed patient transport and increased the number of patients reporting respiratory infection symptoms. Emergency medical services will need administrative and economic support to transport the increased number of patients requiring services.

• Journal of radiological science and technology
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• 제43권5호
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• pp.397-404
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• 2020

Coronavirus disease(COVID-19) is highly infectious disease that directly affects the lungs. To observe the clinical findings from these lungs, the Chest Radiography(CXR) can be used in a fast manner. However, the diagnostic performance via CXR needs to be improved, since the identifying these findings are highly time-consuming and prone to human error. Therefore, Artificial Intelligence(AI) based tool may be useful to aid the diagnosis of COVID-19 via CXR. In this study, we explored various Deep learning(DL) approach to classify COVID-19, other viral pneumonia and normal. For the original dataset and lung-segmented dataset, the pre-trained AlexNet, SqueezeNet, ResNet18, DenseNet201 were transfer-trained and validated for 3 class - COVID-19, viral pneumonia, normal. In the results, AlexNet showed the highest mean accuracy of 99.15±2.69% and fastest training time of 1.61±0.56 min among 4 pre-trained neural networks. In this study, we demonstrated the performance of 4 pre-trained neural networks in COVID-19 diagnosis with CXR images. Further, we plotted the class activation map(CAM) of each network and demonstrated that the lung-segmentation pre-processing improve the performance of COVID-19 classifier with CXR images by excluding background features.

• Journal of the Korea Society of Computer and Information
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• 제29권3호
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• pp.147-154
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• 2024

The coronavirus disease-2019 (COVID-19) pandemic has changed physical activities due to social distancing to prevent the spread of infectious disease. The restriction could affect physical activities and serum lipid levels. The purpose of this study is to investigate changes of serum lipid levels and physical activities due to the social distancing between the pre-and-post COVID-19 pandemic on Jeju Island. A total of 5,373 subjects who underwent medical examination at a medical center located on Jeju Island. between May 2018 and December 2021 was enrolled. They were divided into two groups (the pre-COVID-19 vs. the post-COVID-19) based on their medical checkup dates and analyzed about clinical variables between them. Among the clinical variables, the mean age (P<0.014) and the mean levels of high-density lipoprotein-cholesterol (P=0.001), low-density lipoprotein-cholesterol (P=0.039) and total-cholesterol (P<0.001) and the proportions of subjects with abdominal obesity (P<0.001), aerobic exercise (P=0.003) and physical activity (P=0.008) were significantly higher in the post-COVID pandemic than those in the pre-COVID-19 pandemic. Even though the proportions of subjects with physical activity and aerobic exercise were statistically greater in the post-COVID-19 pandemic, those with central obesity and dyslipidemia were significantly higher in the period than before on Jeju Island.

• Journal of Nutrition and Health
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• 제57권1호
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• pp.153-169
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• 2024

Purpose: The main goal of this study was to identify the impact of coronavirus disease 2019 (COVID-19) on grocery purchases (i.e., fresh and processed foods by grain, vegetable, fruit, seafood, and meat categories) in Korea. To understand the specific impact of COVID-19, the study period was divided into 3 segments: PRE-COVID-19, INTER-COVID-19, and POST-COVID-19. Methods: We used the microdata of household income and expenditure from Statistics Korea (KOSTAT), representing households across the country. The data comprised monthly grocery expenditure data from January 2019 to September 2022. First, we compared the PRE-COVID-19 period to INTER-COVID-19 and then INTER-COVID-19 to POST-COVID-19 and used multiple regression analysis. The covariates used were the gender and age of the head of the household, the household's monthly income, the number of family members, the price index, and the month (dummy variable). Results: The expenditures on all grocery categories except fresh fruit increased from PRE-COVID-19 to INTER-COVID-19. From INTER-COVID-19 to POST-COVID-19, almost all grocery category spending declined, with processed meat being the only exception. Most purchases of protein sources, increased during INTER-COVID-19 compared to PRE-COVID-19, while ham/sausage/bacon for meat protein, fish cakes and canned seafood for seafood protein, and soy milk for plant-based protein did not decrease during POST-COVID-19 compared to INTER-COVID-19. Conclusion: These results show an overall increase in in-home grocery expenditure during COVID-19 due to an increase in eating at home, followed by a decrease in this expenditure in the POST-COVID-19 period. Among the trends, the protein and highly processed convenience food categories did not see a decline in spending during the POST-COVID-19 period, which is a reflection of the preferences of consumers in the post-COVID-19 period.

• Journal of Distribution Science
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• 제20권4호
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• pp.95-100
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• 2022

Purpose: This study aimed to investigate whether distribution and service companies maintained their accounting information quality and provided reliable information despite the economic changes occurring after the outbreak of the COVID-19 pandemic in Korea. The distribution industry has enjoyed increased demand as many companies expanded their untact distribution channels, including to online sales. However, as the pandemic drags on, their future prospects remain uncertain. Research design, data, and methodology: In this study, we define 2018-2019 as the "pre COVID-19 period" and 2020 as the "post COVID-19 period." An empirical analysis was performed using a regression model that includes POST, the independent variable, indicating the post COVID-19 period, and discretionary accruals(DA), a proxy for earnings management, as a dependent variable. Results: The analysis shows that the coefficient of POST is significantly positive (+) for the dependent variable DA. This finding suggests that distribution and service companies engaged in more earnings management during the post COVID-19 period than during the pre COVID-19 period, indicating their awareness of the uncertainty of future business performance as the pandemic persists. An additional analysis confirmed that smaller companies with fewer stakeholders and higher information asymmetry tend to engage more in earnings management than larger companies.

• The Korean Journal of Emergency Medical Services
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• 제25권1호
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• pp.125-134
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• 2021

Purpose: The purposes of this study were to determine the changes in the pattern of patients who were transferred to the emergency room through inter-hospital private institutions and to determine how long transport takes following the COVID-19 outbreak. Methods: This retrospective observational study analyzed the emergency medical services reports of private institutions following the COVID-19 outbreak in South Korea. The study was conducted in Busan between January 19, 2019 and January 18, 2020, and between January 19, 2020 and January 18, 2021. Results: Upon comparing the patient transport times during the "Pre-COVID-19 period" and "COVID-19 period," a significant delay was noticed in the preparation for transfer of patients during the "COVID-19 period" (p<.05). There were significantly more patients with respiratory infections and patients who complained of general symptoms during the "COVID-19 period." Moreover, there was a higher frequency of patients who were transferred to a 'Level I' emergency room during the "COVID-19 period" compared to during the "Pre-COVID-19 period" (p<.05). Conclusion: Following the COVID-19 outbreak, there is a delay in patient transport to the emergency room through private institution inter-hospital transport and an increase in the number of patients complaining of respiratory infection symptoms. Thus, emergency medical services need additional administrative and economic support to transport infected patients.

• Clinical and Experimental Pediatrics
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• 제64권4호
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• pp.157-164
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• 2021

Since the emergence of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) in December 2019, a small number of coronavirus disease 2019 (COVID-19) cases in neonates have been reported worldwide. Neonates currently account for only a minor proportion of the pediatric population affected by COVID-19. Thus, data on the epidemiological and clinical features of COVID-19 in neonates are limited. Approximately 3% of neonates born to mothers with COVID-19 reportedly tested positive for SARS-CoV-2. Current limited data on neonates with COVID-19 suggest that neonatal COVID-19 shows a relatively benign course despite a high requirement for mechanical ventilation. However, neonates with pre-existing medical conditions and preterm infants appear to be at a higher risk of developing severe COVID-19. The greatest perinatal concern of the COVID-19 pandemic is the possibility of vertical transmission, especially transplacental transmission of SARS-CoV-2. Although direct evidence of the vertical transmission of SARS-CoV-2 is lacking, its possibility during late pregnancy cannot be ruled out. This review summarizes available case studies on COVID-19 in neonates and introduces what is currently known about neonatal COVID-19 with focus on its vertical transmission.