• Journal of the Korean Society of International Agriculture
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• v.23 no.5
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• pp.520-530
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• 2011

This study was carried out to evaluate the possibility of rice double cropping in Korea by assessing the growth and yield performance of rice cultivars transplanted at the extremely-early date. When the transplanted rice seedling was exposed to low temperature below 0℃, the survival rate decreased drastically. However, short exposure to below 0℃ one or two times did not damage transplanted rice seedling so severely. Thus, the earliest transplanting in spring would be possible when minimum temperature rises above 0℃. Compared with the conventional seedling nursery tray (CSNT), seedling rearing with the potted nursery tray was more effective for increasing leaf age and seedling dry weight during nursery period. In the first rice cropping, rice cultivation with seedlings reared in PSNT showed shorter growth duration and cumulative temperature from transplanting to heading than that with seedlings reared in CSNT. The earliest heading date on July 4 in Jinbuolbyeo was earlier by two to three days than that of Dunaebyeo. If rice has not exposed to cold damage, the earliest heading date of Jinbujolbyeo can advance to June 30 or July 1. In this case, rice harvest would be possible on August 5, enabling the rice transplanting of the second rice cropping before August 10. At transplanting time with low temperature damage rice yield were less than 400 kg/10a while rice yield exceeded 400 kg/10a at transplanting time without low temperature damage.

• Korean Journal of Heritage: History & Science
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• v.56 no.3
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• pp.174-193
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• 2023

Korea is surrounded by the sea and has rivers connecting to it throughout the inland areas, which has been a geographical characteristic since ancient times. As a result, there have been exchanges and conflicts with various countries through the sea, and rivers have facilitated the transportation of ships carrying grain, goods paid for by taxes, and passengers. Since the past, the sea and rivers have had a significant impact on the lives of Koreans. Consequently, it is expected that there are many cultural heritages submerged in the sea and rivers, and continuous efforts are being made to discover and preserve them. Underwater cultural heritage is difficult to discover due to its location in the sea or rivers, making direct visual observation and exploration challenging. To overcome these limitations, various geophysical survey techniques are employed. Geophysical survey methods utilize the physical properties of elastic waves, including their reflection and refraction, to conduct surveys such as bathymetry, underwater topography and strata. These techniques detect the physical characteristics of underwater objects and seafloor formation in the underwater environment, analyze differences, and identify underwater cultural heritage located on or buried in the seabed. Bathymetry uses an echo sounder, and an underwater topography survey uses a side-scan sonar to find underwater artifacts lying on or partially exposed to the seabed, and a marine shallow strata survey uses a sub-bottom profiler to find underwater heritages buried in the seabed. However, the underwater cultural heritage discovered in domestic waters thus far has largely been accidental findings by fishermen, divers, or octopus hunters. This study aims to analyze and summarize the latest research trends in equipment used for underwater cultural heritage exploration, including bathymetric surveys, underwater topography surveys and strata surveys. The goal is to contribute to research on underwater cultural heritage investigation in the domestic context.

• Pediatric Infection and Vaccine
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• v.31 no.1
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• pp.102-112
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• 2024

Purpose: To identify the epidemiological characteristics and risk factors of coronavirus disease 19 (COVID-19) outbreaks depending on the type of educational facility by analyzing the COVID-19 cluster associated with educational facilities. Methods: This study is based on epidemiological investigation of COVID-19 cluster in Gangwon-do, Korea from December 10, 2020 to September 23, 2021 reported to the Korea Disease Control and Prevention Agency's Integrated Disease and Health Management System. Four hundred seven patients in 19 facilities, classified as cluster related to educational facilities, were the study population. The result of preliminary epidemiology survey report, in-depth epidemiological survey by phone and the result of risk assessment derived from the field epidemiology investigation were retrospectively analyzed to evaluate infectivity and the characteristics of the risk factors. Results: There were total of 407 confirmed patients related to 19 educational facilities, with 204 students under the age of 19 (50.1%). One hundred fifty-five preceding spreaders were from families (38.1%) and 125 were the teachers (30.7%). The place exposed to confirmed patients was the highest with 139 people (34.2%) at home. Conclusions: It was confirmed that the cause of the occurrence of clusters related to educational facilities was higher due to family transmission than the risk of facilities in schools. Nevertheless, continuous efforts should be made to control infection in educational facilities, and that teachers' implementation of principles for prevention of COVID-19 personal hygiene in their daily lives should be strengthened.

• Pediatric Infection and Vaccine
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• v.31 no.1
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• pp.113-121
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• 2024

Purpose: In response to the surge in coronavirus disease 2019 (COVID-19) omicron variant cases, we have implemented preemptive testing for preschool and school. The purpose is to quickly detect COVID-19 cases using a rapid antigen test (RAT) kit so that normal school activities can continue. Methods: The results entered in The Healthcare Self-Test App were merged with the information on the status of confirmed cases in the COVID-19 Information Management System by Korea Disease Control and Prevention Agency (KDCA) for preschool and school of students and staffs March 2 to May 1, 2022 to analyze the RAT positive rate and positive predictive value of RAT. Results: In preschool and school 19,458,575 people were tested, weekly RAT positive rate ranged from 1.10% to 5.90%, positive predictive value of RAT ranged from 86.42% to 93.18%. By status, RAT positive rate ranged from 1.13% to 6.16% for students, 0.99% to 3.93% for staffs, positive predictive value of RAT ranged from 87.19% to 94.03% for students, 77.55% to 83.10% for staffs. RAT positive rate by symptoms ranged from 76.32% to 88.02% for those with symptoms and 0.34% to 1.11% for those without symptoms. As a result of preschool and school RAT, 943,342 confirmed cases were preemptively detected, before infection spread in preschool and school. Conclusions: RAT was well utilized to detect confirmed cases at an early stage, reducing the risk of transmission to minimize the educational gap in preschool and school. To compensate for the limitations of RAT, further research should continue to reevaluate the performance of RAT as new strains of viruses continue to emerge. We will have to come up with various ways to utilize it, such as performing periodic and repeated RAT and parallel polymerase chain reaction.

• Journal of Marine Life Science
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• v.9 no.1
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• pp.9-21
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• 2024

Paralytic shellfish poisoning (PSP) including Saxitoxin (STX) is caused by harmful algae, and poisoning occurs when the contaminated seafood is consumed. The mouse bioassay (MBA), a standard test method for detecting PSP, is being sanctioned in many countries due to its low detection limit and the animal concerns. An alternative to the MBA is the Neuro-2a cell-based assay. This study aimed to establish various test conditions for Neuro-2a assay, including cell density, culture conditions, and STX treatment conditions, to suit the domestic laboratory environment. As a result, the initial cell density was set to 40,000 cells/well and the incubation time to 24 hours. Additionally, the concentration of Ouabain and Veratridine (O/V) was set to 500/50 μM, at which most cells died. In this study, we identified eight concentrations of STX, ranging from 368 to 47,056 fg/μl, which produced an S-shaped dose-response curve when treated with O/V. Through inter-laboratory variability comparison of the Neuro-2a assay, we established five Quality Control Criteria to verify the appropriateness of the experiments and six Data Criteria (Top and Bottom OD, EC₅₀, EC₂₀, Hill slop, and R² of graph) to determine the reliability of the experimental data. The Neuro-2a assay conducted under the established conditions showed an EC₅₀ value of approximately 1,800~3,500 fg/μl. The intra- & inter-lab variability comparison results showed that the coefficients of variation (CVs) for the Quality Control and Data values ranged from 1.98% to 29.15%, confirming the reproducibility of the experiments. This study presented Quality Control Criteria and Data Criteria to assess the appropriateness of the experiments and confirmed the excellent repeatability and reproducibility of the Neuro-2a assay. To apply the Neuro-2a assay as an alternative method for detecting PSP in domestic seafood, it is essential to establish a toxin extraction method from seafood and toxin quantification methods, and perform correlation analysis with MBA and instrumental analysis methods.

• Journal of Food Hygiene and Safety
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• v.26 no.2
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• pp.107-113
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• 2011

Plantago asiatica L. (PA), which is widely distributed in Korea, Japan and China, has traditionally been used as a popular folk medicine for the treatment of liver diseases. A variety of activities of PA was reported, that is hepatoprotective, anti-inflammatory, anti-glycation and anti-oxidant effect. Ferric nitrilotriacetate (Fe-NTA) is a potent nephrotoxic agent and has been reported to induce renal proximal tubular necrosis. In the present study, pre-treatment with PA extract (PAE) in Wistar rat followed by Fe-NTA i.p. treatment (13.5 mg Fe/kg body weight) was performed to detect the renal protective effect of PAE. Only Fe-NTA treated group showed increases in the level of serum blood urea nitrogen (BUN) and serum creatinine (Cr), and renal tissue malondialdehyde (MDA), product of lipid peroxidation. Moreover, the level of biomarkers indicate the antioxidants status, reduced glutathione (GSH), glutathione-S-transferase (GST) and glutathione reductase (GR) were decreased. However, PAE pre-treated group showed decreases in the levels of serum BUN, serum Cr and renal tissue MDA in concentration dependent manner and increases in the level of GSH, GST and GR. These results are significantly different (p < 0.05) to the other groups. Our data suggest that PAE may be used as an chemopreventive material against Fe-NTA-mediated renal oxidative stress.

• Journal of Nutrition and Health
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• v.42 no.2
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• pp.135-145
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• 2009

This study was performed to investigate added sugar intakes from processed food-snacks and participation behaviors of special event days sharing sweet foods among adolescents in Korea. Questionnaire survey (n = 959), dietary survey (n = 71) by food record method for 3 days, and snack survey (n = 230) for 3 days were carried out, and subjects were overlapped among three surveys. As a result, middle school students (MS) preferred milks and fermented milks while high school students (HS) preferred breads and fast foods as a snack (p < 0.01). MS and HS took snacks three to six times a week, and HS took snacks more frequently than MS (p < 0.05). Most subjects participated in special event days sharing sweet foods such as friend's birthday (68.4%), Peppro's day (61.5%) and Valentine's day (42.6%). As for merits of these events, MS said ‘they could get along with their friends' and ‘relieve stress', while HS said ‘they could enjoy their own events' and ‘confess their affection to whom they like' (p < 0.01). A group of cookies, biscuits, breads and, cakes was major source of added sugars followed by beverages, sweet jellies of red bean, chocolates and candies for subjects. For MS and HS, daily total added sugar intakes from whole processed food-snacks were $30.5{\pm}23.5g/d$ (3.0-137.9 g/d) and $31.7{\pm}23.2g/d$ (1.2-126.1 g/d), and ratios of daily total energy taken from added sugars of whole processed food-snacks in proportion to daily total energy taken from diet (energy percent of added sugars from snacks) were $6.3{\pm}4.7%$ (0.6-26.1%) and $6.3{\pm}4.4%$ (0.3-23.9%), respectively. These results showed that subjects frequently participated in special event days sharing sweet foods. In addition, energy percent of added sugars from snacks was more than the UL suggested by WHO/FAO for some subjects. Therefore, it is highly critical to monitor adolescents' sugar intakes on a long-term basis and to take nutritional management on their high sugar intakes.

• Applied Microscopy
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• v.23 no.2
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• pp.27-40
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• 1993

This study was taken to examine the light microscopic and ultrastructural changes of gill and kidney of female tilapia{Oreochromis niloticus) adapted in 0%o, 10%o, 20%o, and 30%o salt concentrations, respectively, by light, scanning and transmission electron microscope. The results obtained in these experiments were summarized as follows: Gill chloride cell hyperplasia, gill lamellar epithelial separation, kidney glomerular shrinkage, blood congestion in kidneys and deposition of hyalin droplets in kidney glomeruli, tubules were the histological alterations in Oreochromis niloticus. Incidence and severity of gill chloride cell hyperplasia rapidly increased together with increase of salinity, and the number of chloride cells in gill lamellae rapidly increased in response to high external NaCl concentrations. The ultrastructure by scanning electron microscope(SEM) indicated that the gill secondary lamella of tilapia(Oreochromis niloticus) exposed to seawater, were characterized by rough convoluted surfaces during the adaptation. Transmission electron microscopy(TEM) indicated that mitochondria in chloride cells exposed to seawater, were both large and elongate and contained well-developed cristae. TEM also showed the increased chloride cells exposed to seawater. The presence of two mitochondria-rich cell types is discussed with regard to their possible role in the hypoosmoregulatory changes which occur during seawater-adaptation. Most Oreochromis niloticus adapted in seawater had an occasional glomerulus completely filling Bowman's capsule in kidney, and glomerular shrinkage was occurred higher in kidney tissues of individuals living in 10%o, 20%o, 30%o of seawater than in those living in 0%o of freshwater, and blood congestion was occurred severer in kidney tissues of individuals living 20%o, 30%o of seawater than in those living in 10%o of seawater. There were decreases in the glomerular area and the nuclear area in the main segments of the nephron, and that the nuclear areas of the nephron cells in seawater-adapted tilapia were of smaller size than those from freshwater-adapted fish. Our findings demonstrated that Oreochromis niloticus tolerated moderately saline environment and the increased body weight living in 30%o was relatively higher than that living in 10%o in spite of histopathological changes.

• Korean journal of food and cookery science
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• v.30 no.6
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• pp.774-784
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• 2014

The purpose of this study was to present management guidelines for critical control points by analyzing microbiological hazardous elements through screening Potentially Hazardous Foods (PHF) menus in an effort improve the microbiological quality of foods prepared by restaurant operations. Steamed spinach with seasoning left at room temperature presents a range of risk temperatures which microorganisms could flourish, and it exceeded all microbiological safety limits in our study. On the other hand, steamed spinach with seasoning stored in a refrigerator had Aerobic Plate Counts of $2.86{\pm}0.5{\log}\;CFU/g$ and all other microbiological tests showed that their levels were below the limit. The standard plate counts of raw materials of lettuce and tomato were $4.66{\pm}0.4{\log}\;CFU/g$ and $3.08{\pm}0.4{\log}\;CFU/g$, respectively. Upon washing, the standard plate counts were $3.12{\pm}0.6{\log}\;CFU/g$ and $2.10{\pm}0.3{\log}\;CFU/g$, respectively, but upon washing after chlorination, those were $2.23{\pm}0.3{\log}\;CFU/g$ and $0.72{\pm}0.7{\log}\;CFU/g$, respectively. The standard plate counts of baby greens, radicchio and leek were $6.02{\pm}0.5{\log}\;CFU/g$, $5.76{\pm}0.1{\log}\;CFU/g$ and $6.83{\pm}0.5{\log}\;CFU/g$, respectively. After 5 minutes of chlorination, the standard plate counts were $4.10{\pm}0.6{\log}\;CFU/g$, $5.14{\pm}0.1{\log}\;CFU/g$ and $5.30{\pm}0.3{\log}\;CFU/g$, respectively. After 10 minutes of chlorination treatment, the standard plate counts were $2.58{\pm}0.3{\log}\;CFU/g$, $4.27{\pm}0.6{\log}\;CFU/g$, and $4.18{\pm}0.5{\log}\;CFU/g$, respectively. The microbial levels decreased as the time of chlorination increased. This study showed that the microbiological quality of foods was improved with the proper practices of time-temperature control, sanitization control, seasoning control, and personal and surface sanitization control. It also presents management guidelines for the control of potentially hazardous foods at the critical control points in the process of restaurant operations.

• Journal of the Korean Institute of Traditional Landscape Architecture
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• v.40 no.1
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• pp.26-42
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• 2022

The purpose of this study is to examine and understand the area and the original outer boundaries of Hamchunwon(含春苑), which was the outer royal garden of Gyeonghuigung Palace, which existed before the site of the Russian legation. The results of the study are as follows. First, examining the 3 types of drawings prepared for securing the Russian legation's site and constructing a new building, it was confirmed that two low peaks, which appear to be the original terrain of Hamchunwon, existed in the north and south directions inside the site. According to the initial plan of the of the legation's site, it appears that the entrance of the legation building is connected to the Saemunan-ro in the northwest. However, according to the report made at the time when the Russian temporary minister Veber purchased the legation's site, it was recorded that the site already had a narrow entrance and a dirt road in place, and hence, it was connected to Saemunan-ro. This fact makes it possible to learn that the line of movement for officials and the original gate were located to the northwest of the site planned as the entrance of the legation building towards Hamchunwon. Second, the site was created by cutting the top of the high hill at the time of the construction of the legation building, and as a result, a two tiered staircase typed terrace was built. The ground on which the main building and the secretary's building, etc., were erected was made by cutting the highest peak and solidifying it flat, and a large quantity of soil was used for grading. In the case of the northern area of the main building, the traces of leveling the terrain by cutting the mountains are apparent, and an observation typed garden with a walking path and pavilion was formed by utilizing the physical environment equipped with an easy view. This may be considered as a use which is consistent with the topographical conditions of creating an outer royal garden to block the civilian views on a high terrain overlooking the palace. Third, Hamchunwon's fences were partially exposed in the photos from the 1880s through the 1890s, which demonstrate the spatial changes made around the US, UK, and the Russian legations. As a result of the photo analysis performed, Hamchunwon occupies the northern area of the Russian legation's site, and it is estimated that the north, west, and east walls of the legation resembled those of Hamchunwon. The area to the south of the Russian legation was originally a place made available for civilian houses, and it was possible to examine the circumstances of purchasing dozens of civilian houses and farmlands according to various materials. Fourth, Hamchunwon, which was formed as the outer royal garden of Gyeongdeokgung Palace of Lord Gwanghaegun, lost its sense of place as an outer royal garden when the entire building of Gyeonghuigung Palace was torn down and used as a construction members during the reconstruction of Gyeongbokgung Palace, and faded away as the site was sold to Russia around 1885. The area where Hamchunwon used to be located transformed into a core space of the Russian legation where the main building and garden were located after the construction of the new building. Hence, Hamchunwon, which was limited to the northern area of the Russian legation, does not carry the temporal and spatial context with Gyeongungung Palace and Seonwonjeon which were constructed after 1897, and it is determined that the view of Seonwonjeon as Baehoorim or Baegyeongrim is not valid.