• Journal of Animal Science and Technology
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• v.62 no.5
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• pp.668-681
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• 2020

The purpose of this study was aimed to isolate a Salmonella Typhimurium-specific phage (KFS-ST) from washing water in a poultry processing facility and to investigate the feasibility of the KFS-ST as a novel bio-receptor for the magnetoelastic (ME) biosensor method. KFS-ST against S. Typhimurium was isolated, propagated, and purified using a CsCl-gradient ultracentrifugation. Morphological characteristics of KFS-ST were analyzed using transmission electron microscopy (TEM). Its specificity and efficiency of plating analysis were conducted against 39 foodborne pathogens. The temperature and pH stabilities of KFS-ST were investigated by the exposure of the phage to various temperatures (-70℃-70℃) and pHs (1-12) for 1 h. A one-step growth curve analysis was performed to determine the eclipse time, latent time and burst size of phage. The storage stability of KFS-ST was studied by exposing KFS-ST to various storage temperatures (-70℃, -20℃, 4℃, and 22℃) for 12 weeks. KFS-ST was isolated and purified with a high concentration of (11.47 ± 0.25) Log PFU/mL. It had an icosahedral head (56.91 ± 2.90 nm) and a non-contractile tail (225.49 ± 2.67 nm), which was classified into the family of Siphoviridae in the order of Caudovirales. KFS-ST exhibited an excellent specificity against only S. Typhimurium and S. Enteritidis, which are considered two of the most problematic Salmonella strains in the meat and poultry. However, KFS-ST did not exhibit any specificity against six other Salmonella and 27 non-Salmonella strains. KFS-ST was stable at temperature of 4℃ to 50℃ and at pH of 4 to 12. The eclipse time, latent time, and burst size of KFS-ST were determined to be 10 min, 25 min and 26 PFU/ infected cell, respectively. KFS-ST was relatively stable during the 12-week storage period at all tested temperatures. Therefore, this study demonstrated the feasibility of KFS-ST as a novel bio-receptor for the detection of S. Typhimurium and S. Enteritidis in meat and poultry products using the ME biosensor method.

• Tuberculosis and Respiratory Diseases
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• v.68 no.5
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• pp.280-285
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• 2010

Background: $QuantiFERON^{(R)}$-TB Gold In Tube (QFT-G IT) has been used for diagnosing latent tuberculosis infection and active tuberculosis (TB) since 2007. However, there has not been enough data on QFT-G IT for universal use in children. In this study, we evaluated the clinical usefulness of the QFT-G IT in pediatric practice. Methods: We retrospectively reviewed the clinical records of 70 patients younger than 18 years of age who had taken QFT-G IT and had a tuberculin skin test (TST) between July 2007 and July 2009 at Wonju Christian Hospital. The subjects were divided into two groups, asymptomatic TB exposure group and disease group. Four patients who were taking immunosuppressants during the study period were excluded. Results: A total of 66 immunocompetent children were included in this study. Among 27 asymptomatic children who had contact histories of TB, 6 (22.2%) were found to be positive by QFT-G IT. Eleven (40.7%) and 5 (18.5%) children were found to be positive by TST with cutoff values of ${\geq}5mm$ and ${\geq}10mm$, respectively. Agreement was fair to good between QFT-G IT and TST (${\kappa}=0.59$: cutoff value ${\geq}5mm$, ${\kappa}=0.7$: cutoff value ${\geq}10mm$). In disease group, 14 patients (35.9%) were diagnosed with active tuberculosis, 8/14 (57.1%) were positive on TST and 9/14 (64.3%) on QFT-G IT. The positive rate of acid-fast bacilli smear, TB-polymerase chain reaction, and culture for tuberculosis was 11% (1/9), 27.3% (3/11) and 33.3% (3/9), respectively. Conclusion: Our data support that the QFT-G IT can be used as an additional diagnostic tool for latent and active tuberculosis infection in children.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.7 no.3
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• pp.229-240
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• 1987

Carbonation of concrete is one type of a chemical process. The reaction mechanism is very complex for the case when low-calcium fly ash and blast furnace slag is added. When fly ash and blast furnace slag is used as an admixture in concrete, they improve compressive strength in the long term, permeability and chemical resistance of concrete by a pozzolanic reaction and latent hydraulic property. On the other hand, the pozzolanic reaction of fly ash and latent hydraulic property of the blast furance slag leads to a reduction of the alkalinity of the concrete. It has been pointed out that this will accelerate the carbonation of the concrete and the corrosion of reinforcement steel embedded in the concrete. In order to clarify the effect of fly ash and blast furance slag on the carbonation of concrete, an accelerated carbonation testing of concrete was carried out by varying the conditions of concrete and the initial curing period in water. The test results of accelerated carbonation were compared to the carbonation test results of concrete stored for 15 years in open air, but protected from rain. As a result, the equation for the rate of carbonation based on compressive strength of concrete was proposed.

• Education of Primary School Mathematics
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• v.23 no.4
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• pp.207-227
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• 2020

The demand for private education in Korea is steadily increasing every year, and the participation rate of private education is increasing as the grade goes down. In order to empirically verify the effectiveness of private education, it is necessary to analyze through longitudinal data that has been mainly investigated over a long period of time. This study investigated the longitudinal changes in mathematics academic achievement and participation time in mathematics private education using longitudinal data from 2013 (4th grade in elementary school) to 2017 (2nd grade in middle school) of the Seoul Education Longitudinal Study. The students were divided into groups in which mathematics academic achievement changed similarly as the grade went up, and the effect of mathematics academic achievement was examined according to the change of participation time in private mathematics education for each group. As a result of the study, it was found that the participation time of private math education of all students continuously increased from the 5th grade of elementary school to the 2nd grade of middle school, and the participation time of private math education by group was different. In addition, the effect of private tutoring by group was different according to the group.

• Korean Journal of Social Welfare Studies
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• v.45 no.2
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• pp.5-30
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• 2014

This study sought to identify developmental trajectories of bullying victimization from late elementary school through early high school, and to examine internalizing and externalizing problem outcomes associated with the trajectory group membership. Data from Seoul Panel Study of Children were collected annually over a 7-year period from 5th grade of elementary school through 2nd grade of high school (2005~2011). Latent class growth analysis yield three trajectory classes corresponding to stable low (81.2%), stable high (3.5%), and declining bullying victimization (15.6%). Findings from analysis of covariance indicated that students in both stable high and declining trajectory groups reported significantly higher means in internalizing behavior (withdrawal, depression/anxiety, and suicide ideation), compared to those in the stable low group. For externalizing behavior such as aggression and juvenile status offense, students in the stable high group showed higher means, compared to those in the stable low and declining trajectory groups. Developmental pattern of bullying victimization over multiple development stages and associated internalizing and externalizing outcomes are discussed as are the implications for the bullying prevention.

• Korean Journal of Culture and Social Issue
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• v.17 no.1
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• pp.19-49
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• 2011

In this study, multilateral conceptualizations of underemployment were measured in terms of wages, social status, skill utilization and permanence of the job, and then the effects of antecedents on underemployment and the effects of underemployment on organizational adaptation were examined. Data obtained by a longitudinally designed survey at intervals of 18 months with the reemployed(N = 153) after job loss were used. The underemployment measures include 1) the ratio of wage change 2) the ratio of status change 3) the ratio of education 4) the occurrence of change from the permanent job to temporary job, 5) overqualification - growth opportunity, 6) overqualification - mismatch. The first four measures are social-economic and objective measures and the last two measures are psychological and self-reported ones. Demographic variables(sex, age, education level, and period of unemployed), circumstantial variables(economic hardship, number of dependents), and psychological variables(job-seeking self-efficacy, depression/anxiety, latent function) are included in antecedents. In the effects of antecedents on underemployment, age increases the level of underemployment in the aspects of wage and job status. Economic hardship increases the possibility of underemployment in the aspects of education and number of dependents increases the possibility of underemployment in the aspects of job status. Job seeking self-efficacy decreases the possibility of underemployment in the overqualification - no growth. Retention of latent function during the period of unemployment lowers the possibility of underemployment in the overqualification - no growth. The level of depression and anxiety during the period of unemployment raises the possibility of underemployment in terms of education and in the overqualification - mismatch. In the effects of underemployment on organizational adaptation, the higher the level of underemployment in the aspect of education is, the lower the level of person-organization fit, emotional commitment, and job satisfaction are. And the transition from permanent job to temporary job makes emotional commitment and job satisfaction lower. No growth and mismatch exerted a significant influence on organizational adaptation generally.

• Journal of Korea Water Resources Association
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• v.49 no.6
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• pp.551-563
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• 2016

According to the 4th and 5th assessment of the Intergovernmental Panel on Climate Change (IPCC), global climate has been rapidly changing because of the human activities since Industrial Revolution. The perceived changes were appeared strongly in temperature and concentration of carbon dioxide ($CO_2$). Global average temperature has increased about $0.74^{\circ}C$ over last 100 years (IPCC, 2007) and concentration of $CO_2$ is unprecedented in at least the last 800,000 years (IPCC, 2014). These phenomena influence precipitation, evapotranspiration and soil moisture which have an important role in hydrology, and that is the reason why there is a necessity to study climate change. In this study, Asia region was selected to simulate primary energy index from 1951 to 2100. To predict future climate change effect, Common Land Model (CLM) which is used for various fields across the world was employed. The forcing data was Representative Concentration Pathway (RCP) data which is the newest greenhouse gas emission scenario published in IPCC 5th assessment. Validation of net radiation ($R_n$), sensible heat flux (H), latent heat flux (LE) for historical period was performed with 5 flux tower site-data in the region of AsiaFlux and the monthly trends of simulation results were almost equaled to observation data. The simulation results for 2006-2100 showed almost stable net radiation, slightly decreasing sensible heat flux and quite increasing latent heat flux. Especially the uptrend for RCP 8.5 has been about doubled compared to RCP 4.5 and since late 2060s, variations of net radiation and sensible heat flux would be significantly risen becoming an extreme climate condition. In a follow-up study, a simulation for energy index and hydrological index under the detailed condition will be conducted with various scenario established from this study.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.29 no.1
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• pp.84-91
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• 1996

Heat flux of the East China Sea was estimated with the bulk method, the East China mount based on the marine meteorological data and cloud amount data observed by a satellite. Solar radiation is maximum in May and minimum in December. Its amount decreases gradually southward during the winter half year (from October to March), and increases northward during the summer half year (from April to September) due to the influence of Changma (Baiu) front. The spatial difference of long-wave radiation is relatively small, but its temporal difference is quite large, i.e., the value in February is about two times greater than that in July. The spatial patterns of sensible and latent heat fluxes reflect well the effect of current distribution in this region. The heat loss from the ocean surface is more than $830Wm^{-2}$ in winter, which is five times greater than the net radiation amount during the same period, The annual net heat flux is negative, which means heat loss from the sea surface, in the whole region over the East China Sea. The region with the largest loss of more than $400Wm^{-2}$ in January is observed over the southwestern Kyushu. The annual mean value of solar radiation, long-wave radiation, sensible and latent heat fluxes are estimated $187Wm^{-2},\;-52Wm^{-2},\;-30Wm^{-2}\;and\;-137Wm^{-2}$, respectively, consequently the East China Sea losses the energy of $32Wm^{-2}(2.48\times10^{13}W)$. Through the heat exchange between the air and the sea, the heat energy of $0.4\times10^{13}W$ is supplied from the air to the sea in A region (the Yellow Sea), $2.1\times10^{13}W$ in B region (the East China Sea) and $1.7\times10^{13}W$ in C region (the Kuroshio part), respectively.

• Pediatric Infection and Vaccine
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• v.26 no.1
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• pp.32-41
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• 2019

Purpose: In order to prevent tuberculosis transmission early, it is important to diagnose and treat tuberculosis infection by investigating people who have contact with patients with active tuberculosis. Methods: From July 2014 to June 2017, the intrafamilial childhood contacts of the patients who were diagnosed with active tuberculosis at Chungnam National University Hospital were investigated for the presence of tuberculosis infection. We also retrospectively analyzed the treatment status of children treated with latent tuberculosis infection (LTBI) during the same period. Results: Among the 269 children who had intrafamilial contact with active tuberculosis patient, 20 (7.4%) did not receive any screening. At the first screening, one (0.4%) was diagnosed with pulmonary tuberculosis, seven (2.8%) had a previous history of tuberculosis infection, and 42 patients (16.9%) were diagnosed with LTBI. At the second screening, 29 patients (11.6%) were diagnosed with LTBI, and 61 patients did not finish the investigation. Only 188 (69.9%) out of 269 patients completed the investigation. Ninety patients received treatment for LTBI and 83 patients (92.2%) completed the treatment, of which 18 patients had side effects such as rash, fatigue, and gastrointestinal symptoms. However, there were no serious side effects requiring treatment discontinuation. Conclusions: The completion rate of childhood tuberculosis contact investigation was low, but the completion rate of LTBI treatment was high in children without serious side effects. In order to prevent and manage the spread of tuberculosis, active private-public partnership efforts and education of the patient and guardian are needed.

• Atmosphere
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• v.25 no.1
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• pp.31-49
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• 2015

From the hourly data of 75 Korean weather stations over a 12-year period (2001~2012), this study has chosen three cases (January 12, 2006; January 11, 2008; and February 22, 2009) of multiple freezing rains and investigated the atmospheric circulations that seemed to cause the events. As a result, the receding high pressure type (2006), prevailing high pressure type (2008), and warm front type (2009) are confirmed as synoptic patterns. In all three cases, freezing rain was found in regions with a strong ascending current near the end point of a low-level jet that carried the warm humid air from low latitudes. The strong ascending current resulted from lower-level convergence and upper-level divergence. In 2006 and 2009, the melting process was confirmed. In 2008, the supercooled warm rain process (SWRP) was confirmed. In contrast to existing SWRP theory, it was found that the cool air produced at the middle atmosphere and near the earth's surface led to the formation of freezing rain. The sources of this cool air were supposed to be the evaporative latent heat and the cold advection coming from the northeast. On the other hand, a special case was detected, in which the freezing rain occurred when both the soil surface temperature and surface air temperature were above $0^{\circ}C$. The thickness distributions related to freezing rain in Korea were found to be similar to those in North America. A P-type nomogram was considered for freezing rain forecasting; however, it was not relevant enough to Korea, and few modifications were needed.