• Neonatal Medicine
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• v.17 no.1
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• pp.64-74
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• 2010

Purpose : The aim of this study was to determine the risk factors, clinical characteristics and prognosis for the development of periventricular leukomalacia (PVL) in preterm infants according to the extent and site of the PVL. Methods : The medical records of infants (under 36 weeks of gestational age) delivered from January 1999 to December 2008 were reviewed. Twenty-five preterm infants with were PVL were diagnosed by brain magnetic resonance imaging (MRI) and an addition 50preterm infants with no brain lesions were enrolled in this study. The perinatal and neonatal risk factors for the development of PVL was determine in these infants. Mental and Psychomotor Developmental Indices (MDI, PDI) were assessed by a clinical psychologist using the Bayley Scales of Infant Development II. We compared the differences of the clinical characteristics and prognosis according to brain MRI findings. Results : Maternal fever, young maternal age, extended oxygen use, hypotension within the first week of birth, use of inotropics within the first week of birth, and respiratory distress syndrome were the risk factors associated with PVL (P <0.05). In the multivariate analysis, maternal fever and extended oxygen use were statistically significant independent risk factors (P <0.05). The mean MDI and PDI scores of the PVL group (74.4$\pm$ 27.8 and 58.0$\pm$17.7) were significantly lower than those of the control group (103.5$\pm$8.9 and 101.7$\pm$16.1, P <0.05). Conclusion : Maternal fever and extended oxygen use were independent risk factors for PVL. We should pay attention to infants who had the risk factors and follow them up closely by brain imaging study and Bayley Scales of Infant Development II.

• Neonatal Medicine
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• v.17 no.1
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• pp.75-83
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• 2010

Purpose : This study was performed to determine the predictors of failed closure of a patent ductus arteriosus (PDA) following the first course of indomethacin in symptomatic preterm infants. Methods : Forty three of 43 preterm infants, admitted to the neonatal intensive care unit diagnosed with PDA and treated with indomethacin at the Korea University Medical Center between January 1990 and October 2007, ware studied. The perinatal risk factors affecting the failed closure of PDA were retrospectively assessed. Results : The failed PDA closure group included 16 (37%) out of 43 infants three of whom underwent surgery. The closure group included 27 (63%) out of 43 infants. In the failed closure group, the Apgar scores (1 min, 5 min) were significantly higher (P<0.05) and antenatal steroid administration was significantly lower (P<0.05). In addition, dopamine administration was significantly lower (P<0.05) and the mean postnatal age at diagnosis was significantly lower (P<0.05). Multiple logistic regression for the prediction of failed PDA closure found only antenatal steroid administration (OR 0.092, CI 0,010-0.826, P=0.0331) as an associated factor. Conclusion : In patients with antenatal steroid administration the failed PDA closure rate was significantly lower. Therefore, antenatal steroid administration can be considered as an important factor for the closure of PDA in preterm pregnancies.

• Neonatal Medicine
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• v.16 no.2
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• pp.163-171
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• 2009

Purpose: This study was conducted to determine the incidence, causative pathogens, risk factors and mortality for early onset sepsis in the first three days in very low birth weight infants. Methods: The medical records of 1,124 very low birth weight infants admitted to the neonatal intensive care unit of Samsung Medical Center between November 1994 and December 2008 were retrospectively reviewed. The incidence, causative pathogens, risk factors, and mortality for early onset sepsis in the first 3 days of life in very low birth weight infants were evaluated. Results: Early onset sepsis, as confirmed by positive blood cultures, was present in 17 of 1,124 infants (1.5%). Sixty-four percent of the isolated pathogens were gram-positive bacteria and 35% of the isolated pathogens were gram-negative bacteria. The dominant pathogens of early onset sepsis included Staphylococcus aureus (23.5%), Esherichia coli (23.5%), and Enterococcus (17.6%). Vaginal delivery (adjusted odds ratio [OR], 3.7; 95% confidence interval [CI], 1.3-10.3; P=0.01) was associated with early onset sepsis. The overall mortality (adjusted hazard ratio, 3.0; 95% CI, 1.4-6.5; adjusted P=0.0039) and mortality within 72 hours of life (adjusted hazard ratio, 6.5; 95% CI, 2.2-18.9; adjusted P=0.0005) of infants with early onset sepsis were higher than that of uninfected infants. Conclusion: Early onset sepsis remains an uncommon, but potentially lethal problem among very low birth weight infants. Knowledge of the likely causative organisms and risk factors for early onset sepsis can aid in instituting prompt and appropriate therapy, in order to minimize mortality.

• Korean Journal of Organic Agriculture
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• v.27 no.4
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• pp.479-499
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• 2019

This study was conducted to investigate the responses of soil properties and microbial communities to different agricultural management and soil types, including organic management in Andisols (Org-A), organic management in Non-andisols (Org-NA), conventional management in Andisols (Con-A) and conventional management in Non-andisols (Con-NA) by using a pyrosequencing approach of 16S rRNA gene amplicon in Radish farms of volcanic ash soil in Jeju island. The results showed that agricultural management systems had a little influence on the soil chemical properties but had significant influence on microbial communities. In addition, soil types had significant influences on both the soil chemical properties and microbial communities. Organic farming increased the microbial density of bacteria and biomass C compared to conventional farming, regardless of soil types. Additionally, Org-NA had the highest dehydrogenase activity among treatments, whereas no difference was found between Org-A, Con-A and Con-NA and had the highest species richness (Chao 1) and diversity (Phyrogenetic diversity). Particularly, Chao 1 and Phyrogenetic diversity were increased in organic plots by 12% and 20%, compared with conventional plots, respectively. Also, regardless of agricultural management and soil types, Proteobacteria was the most abundant bacterial phylum, accounting for 21.9-25.9% of the bacterial 16S rRNAs. The relative abundance of putative copiotroph such as Firmicutes was highest in Org-NA plot by 21.0%, as follows Con-NA (13.1%), Con-A (6.7%) and Org-A (5.1%.), respectively and those of putative oligotrophs such as Acidobacteria and Planctomycetes were higher in Con-A than those in the other plots. Furthermore, LEfSe indicated that organic system enhanced the abundance of Fumicutes, while conventional system increased the abundance of Acidobacteria, especially in Non-andisols. Correlation analysis showed that total organic carbon (TOC) and nutrient levels (e.g. available P and exchangeable K) were significantly correlated to the structure of the microbial community and microbial activity. Overall, our results showed that the continuous organic farming systems without chemical materials, as well as the soil types made by long-term environmental factors might influence on soil properties and increase microbial abundances and diversity.

• Korean Journal of Agricultural and Forest Meteorology
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• v.22 no.3
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• pp.183-193
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• 2020

This study was conducted to evaluate the effect of environment factors on the growth of autumn season cultivation of Kimchi cabbage using the big data in terms of public open data(weather, soil information, and growth of crop, etc.). The growth data and the environment data such as temperature, daylength, and rainfall from 2010 to 2019 were collected. As a result of composing the correlation matrix, the height and leaf number showed high correlation in growing degree days(GDDs) and daylength, and the yield showed negative correlation in growing degree days and the concentration of clay. GDDs and daylength explained about 89% and 84% of variation in height, respectively. These two environmental factors also explained about 85% and 79% of variation in leaf numbers, respectively. In contrast, the coefficient of determination was low for yield when GDDs and concentration of clay was used. The outcome of regional statistical analysis indicated that relationship between yield and sum of sand and silt were high in Haenam and Jindo areas. Hierarchical cluster analysis, which was performed to verify the association of yield, GDDs, and concentration of clay, showed that Haenam and Jindo were clustered together. Although GDDs and yield vary by year and region, and there are regions with similar concentration of clays, observation data are grouped as the result. These suggests that GDDs and soil texture are expected to be related to yield. The cluster analysis results can be used for further data analysis and agricultural policy establishment.

• Korean Journal of Agricultural and Forest Meteorology
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• v.17 no.3
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• pp.248-253
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• 2015

This study was conducted to determine the impact of temperature elevated based on climate change scenario on growth and fruit quality of red pepper (Capsicum annuum L.) in walk-in plant growth chambers. The intraday temperatures of climate normal years (IT) were determined using intraday mean temperatures of climatic normal years (1971~2000) in the Andong Province during the growing season (May 1~July 30). Red pepper plants were cultivated under different temperatures (starting at IT rise by up to $6^{\circ}C$, $2^{\circ}C$ increment). Plant height, stem diameter, branch number, leaf number, fresh weight and dry weight increased under the temperatures higher than IT. The number of flower was the greatest under IT+$2^{\circ}C$ (mean temperature at $22.8^{\circ}C$). The total number and the weight of fruits were the highest under IT+$2^{\circ}C$. While the fruit weight, fruit length and fruit diameter decreased more than IT+$2^{\circ}C$ as the temperature increased gradually. These results concluded that in condition that the current diurnal temperature change cycle is maintained in Andong area, in accordance with climate change scenarios, when the temperature rise $2^{\circ}C$ higher than intraday temperature of Andong area the quantity of pepper fruits will increase while maintaining quality, but increases more than that degree yields are expected to decrease significantly. This result suggests that the fruit yield could increase under IT+$2^{\circ}C$ and fruit quality could maintain great, but the fruit yield could decrease under the temperatures higher than IT+$2^{\circ}C$.

• Korean Journal of Environmental Agriculture
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• v.31 no.4
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• pp.300-307
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• 2012

BACKGROUND: The Transfer Factor (TF) of heavy metals from soil to plant is important, because TF is an indicator of heavy metal in soils and a factor that quantifies bioavailability of heavy metals to agricultural products. This study was conducted to investigate the transfer ability of Arsenic (As), Cadmium (Cd), and Lead (Pb) from soil to agricultural products. METHODS AND RESULTS: We investigated heavy metals (As, Cd and Pb) concentrations in 9 agricultural products (rice, barely, corn, pulse, lettuce, pumpkin, apple, pear, tangerin) and soil. TF of agricultural products was evaluated based on total and HCl-extractable soil concentration of As, Cd, and Pb. Regression analysis was used to predict the relationship of total and HCl-extractable concentration with agricultural product contents of As, Cd, and Pb. The result showed that TF was investigated average 0.006~0.309 (As), 0.002~6.185 (Cd), 0.003~0.602 (Pb). The mean TF value was the highest as rice 0.309 in As, lettuce 6.185, pear 0.717, rice 0.308 in Cd, lettuce 0.602, pumpkin 0.536 in Pb which were dependent on the vegetable species and cereal is showed higher than fruit-vegetables in As. CONCLUSION(S): Soil HCl-extractable concentration of As, Cd, and Pb had the larger effects on thier contents in agricultural products than total soil concentrations. We suggests that TF are served as influential factor on the prediction of uptake. Further study for uptake and accumulation mechanism of toxic metals by agricultural products will be required to assess the human health risk and need TF of more agricultural products.

• Korean Journal of Environmental Agriculture
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• v.31 no.1
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• pp.37-44
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• 2012

BACKGROUND: Many edible mushrooms are known to accumulate high levels of heavy metals. This research was focused on health risk assessment to investigate the mushrooms in Korea, arsenic (As), cadmium (Cd), lead (Pb) and mercury (Hg) contaminations in edible mushrooms in cultivated areas were investigated, and health risk was assessed through dietary intake of mushrooms. METHODS AND RESULTS: The heavy metals in mushrooms were analyzed by ICP/MS after acid digestion. Probabilistic health risk were estimated by Monte-Carlo simulation techniques. The average contents of As, Cd, Pb, and Hg were $0.035{\pm}0.042$ mg/kg, $0.017{\pm}0.020$ mg/kg, $0.043{\pm}0.013$ mg/kg, and $0.004{\pm}0.004$ mg/kg, respectively. The results showed that contents of Cd and Pb did not exceed maximum residual levels established by European Uion regulation (Cd 0.20 mg/kg and Pb 0.30 mg/kg). For health risk assessment, estimated intakes in all age populations did not exceed the provisional tolerable daily intake of As and Hg, provisional tolerable monthly intake of Cd, provisional tolerable weekly intake of Pb. The Hazard Index (HI) were ranged from $0.03{\times}10^{-4}{\sim}0.01{\times}10^{-3}$ for As, $0.02{\times}10^{-3}{\sim}0.81{\times}10^{-3}$ for Cd, $0.06{\times}10^{-3}{\sim}0.38{\times}10^{-3}$ for Pb, and $0.08{\times}10^{-4}{\sim}0.14{\times}10^{-3}$ for Hg at general population. CONCLUSION: The HI from the ratio analysis between daily exposure and safety level values was less than 1.0. This results demonstrated that human exposure to heavy metals through dietary intake of mushrooms might not cause adverse effect.

• Journal of Food Hygiene and Safety
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• v.28 no.4
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• pp.324-329
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• 2013

This study investigated and evaluated contamination levels of bacteria on tomatoes at farms stage to evaluate potential hazards associated with fresh tomatoes. A total of 170 samples, 90 samples from 5 sampling sites from 18 farms and 80 samples from 1 sampling site from 4 farms every month for four months, were analyzed to enumerate aerobic bacterial counts, coliforms, E. coli, Bacillus cereus, Staphylococcus aureus, Escherichia coli, E. coli O157:H7, Salmonella spp., and Listeria monocytogenes. Aerobic bacterial counts ranged from 0.48 to 6.15 Log CFU/g, with the lowest and the highest bacterial cell counts recorded for A site and E site, respectively. Thirty five percent of the samples from the E site contained more than 2 Log CFU/g. Six samples (6.6%) of 90 samples contained B. cereus less than 1 Log CFU/g. In addition, the contamination level of indicator bacteria and B. cereus in tomatoes were higher on March than on April, May and June (P < 0.05). S. aureus, E. coli, E. coli O157:H7, Salmonella spp. and L. monocytogenes were not detected in the tomato samples. The microbial contamination levels of tomatoes determined in this study may be used as the data for microbiological risk assessment.

• Korean Journal of Agricultural and Forest Meteorology
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• v.17 no.3
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• pp.254-260
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• 2015

Changes of the growth, quality and physiological response of Chinese cabbage cv 'Chunkwang' in response to five different temperature treatments based on climate change scenario were investigated during the growing season. The treatments consisted of normal year temperature $-2.0^{\circ}C$ (I), normal year temperature (II; Control group), normal year temperature $+2.0^{\circ}C$ (III), normal year temperature $+4.0^{\circ}C$ (IV), and normal year temperature $+6.0^{\circ}C$ (V). Regarding fresh weight, number of leaves, and leaf area were high in group IV, and V before the head formation stage, but it has decreased during the later growth period. Rate of frangibleness sympton was the highest in group V as 85.7%, and it was decreased in group IV (64.3%), group III (28.6%), group II (14.3%), and group I (7.1%). Regarding photosynthetic rate, group III, IV, and V showed relatively high photosynthetic rate at 20 DAP but it was reduced dramatically during the later growth period. Transpiration and stomatal conductance showed the similar trend with the photosynthetic rate. When comparing the chlorophyll fluorescence reaction of each treatment group at 50 DAP, Fv/Fm in group I was highest as 8.04 among all treatment groups and the lowest in group IV as 7.15.