• Korean Journal of Radiology
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• v.22 no.7
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• pp.1213-1224
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• 2021

Objective: To develop a machine learning (ML) pipeline based on radiomics to predict Coronavirus Disease 2019 (COVID-19) severity and the future deterioration to critical illness using CT and clinical variables. Materials and Methods: Clinical data were collected from 981 patients from a multi-institutional international cohort with real-time polymerase chain reaction-confirmed COVID-19. Radiomics features were extracted from chest CT of the patients. The data of the cohort were randomly divided into training, validation, and test sets using a 7:1:2 ratio. A ML pipeline consisting of a model to predict severity and time-to-event model to predict progression to critical illness were trained on radiomics features and clinical variables. The receiver operating characteristic area under the curve (ROC-AUC), concordance index (C-index), and time-dependent ROC-AUC were calculated to determine model performance, which was compared with consensus CT severity scores obtained by visual interpretation by radiologists. Results: Among 981 patients with confirmed COVID-19, 274 patients developed critical illness. Radiomics features and clinical variables resulted in the best performance for the prediction of disease severity with a highest test ROC-AUC of 0.76 compared with 0.70 (0.76 vs. 0.70, p = 0.023) for visual CT severity score and clinical variables. The progression prediction model achieved a test C-index of 0.868 when it was based on the combination of CT radiomics and clinical variables compared with 0.767 when based on CT radiomics features alone (p < 0.001), 0.847 when based on clinical variables alone (p = 0.110), and 0.860 when based on the combination of visual CT severity scores and clinical variables (p = 0.549). Furthermore, the model based on the combination of CT radiomics and clinical variables achieved time-dependent ROC-AUCs of 0.897, 0.933, and 0.927 for the prediction of progression risks at 3, 5 and 7 days, respectively. Conclusion: CT radiomics features combined with clinical variables were predictive of COVID-19 severity and progression to critical illness with fairly high accuracy.

• Korean Journal of Weed Science
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• v.2 no.1
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• pp.20-30
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• 1982

A field experiment was conducted in 1981 at the Crop Experiment Station, Suweon, Korea, in machine transplanted paddy rice field, to study the effectiveness of single herbicide, mixture, and systematic application of herbicides on diversity of weed control spectrum. The rice variety planted was Taebaegbyeo, Indica ${\times}$ Japonica cross bred. Experimental field was dominated by Echinochtoa crusgalli, Eleocharis kuroguwai, and Scirpus hotarui, and importance values based on dry weight of these weeds were 89%, 5%, and 3%, respectively. The mixture or systematic treatments of herbicide were generally more effective than single herbicide applications on weed control. Coefficients of similarity based on floristic composition after herbicide application between Perfluidone (5G) and Chloromethoxynil (7G), and between Pertluidone (5G) and Bifenox (7G), and between Perfluidone (5G) and three types of Butachlor (6G) were low, and these sets seemed to be a good mixture herbicide in paddy fields. While, Perfluidone (5G) had low coefficient of similarity with other single herbicides tested. The information on coefficient of similarity could be used as parameter for selecting herbicides to increase the efficiency of herbicidal performance. Simpson's indices from Butachlor (3.5G)/SL-49 (7G), Butachlor (3.5G)/Pyrazolate (6G), and Perfluidone (5G) treatments were high, and these herbicide treatments tended to the weed community type simplified, while the indices from Perfluidone (5G) + Chloromethoxynil (7G), Butachlor (6G) fb Perftuidone (5G), and Butachlor (4G)/Naproanilide (6G) treatments were low, and these herbicide treatments caused to the community type diversified in terms of floristic composition.

• Journal of Korean Society of Forest Science
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• v.84 no.2
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• pp.131-144
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• 1995

To determine the structure of chromosome and to identify the sex chromosome of Ginkgo biloba and G. biloba var. fastigiata, the samples were obtained from root tips of trees growing in seven different provinences. The results are as follows. The basic number of somatic chromosomes was 2n=24. The range of a relative length of long chromosome was between $14.88{\sim}11.18{\mu}m$ and that of short chromosome was $8.11{\sim}6.24{\mu}m$. The chromosome sets were composed with one long pairs of m type and 11 short pairs of sm or st type. These short pairs showed the continuous descending in length. There was a satellite on the short arm of the Longest chromosome pair, and were satellites of the one or both long arm of 7th or 8th chromosome pair which were sm or st type, or the shortest st type chromosome pair. Sometimes, a satellite on the short arm of the longest chromosome pairs of Ginkgo biloba was double satellite, but that of G. biloba var. fastigiata was not. Karyotype was $2n=24=2^{2s}A^m+2B^{st\;or\;sm}+2C^{st}+2D^{st}+2E^{st}+2F^{st\;or\;sm}+2G^{sm}+2^{2s}H^{sm}\;or\;(^{1s}H^{sm}+H^{sm})+2I^{st}+2J^{st}+2K^{st}+2^{2s}L^{st}\;or\;(^{1s}L^{st}+L^{st})$. The male and female trees were not apparently distinguished by the chromsome structures. However the differences between the satellites could be used to identify the male and females. The male tree has double satellite on short arm of a longest chromosome pairs and females' has not. Also female trees have a satellite on a short chromosome more frequently than male trees.

• Pediatric Gastroenterology, Hepatology & Nutrition
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• v.4 no.1
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• pp.28-33
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• 2001

Purpose: H. pylori infection is thought to contribute to iron-deficiency anemia, especially during puberty. The ferritin protein Pfr of H. pylori is homologous to eukaryotic and prokaryotic ferritins. The purpose of this study was to analyze the H. pylori pfr status in gastric biopsy specimens according to clinical data, including antral gastritis with or without iron-deficiency anemia. Methods: A total of 26 H. pylori-positive patients aged from ten to 18 years were categorized into subgroups based on the presence or absence of iron-deficiency anemia. All of them had antral gastritis. Sixteen patients were proved to have iron-deficiency anemia by hematological study, two of which had a duodenal ulcer. The other ten patients showed normal hematological findings. DNA isolation was performed from each of the gastric biopsy specimens. PCR amplification of the pfr gene coding was done using two sets of primers. The pfr region, 501 bp, was generated by linking the sequences of the two PCR products. The nucleotide and protein sequences were compared between the pfr regions from Korean H. pylori strains and the NCTC 11638, 26695, and J99 strain, which were obtained from the Genbank. Sequence comparisons were also performed for the pfr regions between the iron-deficiency anemia (+) and (-) groups. Results: Analysis of the complete coding region of pfr gene revealed three sites of mutation. The Ser39Ala mutation was found in 100% (26/26), Gly111Asn in 26.9% (7/26), and Gly82Ser in 11.5% (3/26). There were no significant differences in the mutations of the pfr regions between the iron deficiency anemia (+) and (-) groups. Conclusion: The mutation in the pfr gene did not relate with the clinical phenotype, iron deficiency anemia. Further studies are needed on the aspects of host side or other complex factors to elucidate anemia. Further studies are needed on the aspects of host side or other complex factors to elucidate the mechanisms by which the H. pylori infection might lead to iron deficiency anemia.

• Journal of Korea Water Resources Association
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• v.56 no.12
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• pp.993-1003
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• 2023

Due to the increasing greenhouse gas emissions, the global mean temperature has risen by 1.1℃ compared to pre-industrial levels, and significant changes are expected in functioning of water supply systems. In this study, we assessed impacts of climate change and instreamflow management on water supply reliability in the Geum River basin, Korea. We proposed univariate climate response functions, where mean precipitation and potential evaporation were coupled as an explanatory variable, to assess impacts of climate stress on multiple water supply reliabilities. To this end, natural streamflows were generated in the 19 sub-basins with the conceptual GR6J model. Then, the simulated streamflows were input into the Water Evaluation And Planning (WEAP) model. The dynamic optimization by WEAP allowed us to assess water supply reliability against the 2020 water demand projections. Results showed that when minimizing the water shortage of the entire river basin under the 1991-2020 climate, water supply reliability was lowest in the Bocheongcheon among the sub-basins. In a scenario where the priority of instreamflow maintenance is adjusted to be the same as municipal and industrial water use, water supply reliability in the Bocheongcheon, Chogang, and Nonsancheon sub-basins significantly decreased. The stress tests with 325 sets of climate perturbations showed that water supply reliability in the three sub-basins considerably decreased under all the climate stresses, while the sub-basins connected to large infrastructures did not change significantly. When using the 2021-2050 climate projections with the stress test results, water supply reliability in the Geum River basin was expected to generally improve, but if the priority of instreamflow maintenance is increased, water shortage is expected to worsen in geographically isolated sub-basins. Here, we suggest that the climate response function can be established by a single explanatory variable to assess climate change impacts of many sub-basin's performance simultaneously.

• Investigative Magnetic Resonance Imaging
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• v.16 no.1
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• pp.25-30
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• 2012

Purpose : To compare the enhancement pattern of normal facial nerves on 3D-FLAIR and 3D-T1-FFE-F) sequences at 3.0 T MR units. Materials and Methods: We assessed 20 consecutive subjects without a history of facial nerve abnormalities who underwent temporal bone MRI with contrast enhancement between January 2008 and March 2009. Two neuroradiologists independently reviewed pre-/post-enhanced 3D-T1-FFE-FS and 3D-FLAIR images respectively with 2-week interval to assess the enhancement of normal facial nerves divided into five anatomical segments. The degree of enhancement in each segment was graded as none, mild or strong, and the results of 3D-FLAIR and 3D-T1-FFE-FS image sets were compared. Results: On 3D-FLAIR images, one of the two reviewers observed mild enhancement of the genu segment in two (10%) subjects. On 3D-T1-FFE-FS images, at least one segment of the facial nerve was enhanced in 13 (65%) subjects. At least one reviewer found that 17 of the 100 segments showed enhancement on 3D-T1-FFE-FS images, with the mastoid segment being the most commonly enhanced. Interobserver agreement on 3D-T1-FFE-FS images was good for enhancement of the normal facial nerve (${\kappa}$= 0.589). Conclusion: In contrast to 3D-T1-FFE-FS, normal facial nerve segments rarely showed enhancement on 3D-FLAIR images.

• Journal of Animal Science and Technology
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• v.45 no.5
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• pp.703-710
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• 2003

The purpose of this study was to detect association between genetic variation and economic trait in the porcine heart type fatty acid-binding protein gene as a candidate gene for the traits related with growth and meat quality in pigs. The H-FABP is a 15-kDa protein expressed in several tissues with high demand for fat metabolism such as cardiac and skeletal muscle and lactating mammary gland. H-FABP is small intracellular protein involved in fatty acid transport from the plasma membrane to the site of $\beta$-oxidation and/or triacylglycerol or phospholipid synthesis. In this study, H-FABP PCR-RFLP was performed in F$_2$ population composed of 214 individuals from an intercross between Korean Native Boars and Landrace sows. PCR products from two primer sets within H-FABP gene were amplified in 850bp and 700bp. Digestion of PCR products with the restriction digestion enzymes HaeⅢ and HinfⅠ, revealed fragment length polymorphisms(RFLPs). The genotype frequencies from H-FABP/HaeⅢ was .29 for genotype DD, .53 for genotype Dd, and .15 for genotype dd, respectively. The genotype frequencies of HH, Hh, and hh from H-FABP/HinfⅠ was .38, .41 and .20, respectively, in the population. Relationships between their genotypes and economic traits were estimated. In H-FABP/HaeⅢ locus, there were specific genotypes(Dd and dd) associated with economic traits such as body weights at 3, 5, 12, and 30 week of age (p〈.05 to .001). The ‘d’ allele was associated with gaining of body weight. In H-FABP/HinfⅠ locus, Genotypes of HH and Hh associated with growth traits such as body weights at 5, 12, and 30 week of age (p〈.05 or p〈.001) and back fat thickness, body fat including abdominal and trimmed fat (p〈.001) and intramuscular fat(p〈.05) The ‘H’ allele was positively associated with gaining of body weight and fatness deposition. In conclusion, a significant association of the H-FABP gene from its genetic variation was found on body weight, intramuscular fat and backfat thickness.

• Korean Journal of Agricultural and Forest Meteorology
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• v.7 no.4
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• pp.240-249
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• 2005

The normal Indian Ocean is characterized by warmer waters over the eastern region and cooler waters over the western region. Changes in sea surface temperature (SST) over the western and eastern Indian Ocean give birth to a phenomenon now referred to as the Indian Ocean Dipole Mode (IODM). The positive phase of this mode is characterized by positive SST anomalies over the western Indian Ocean and negative anomalies over the southeastern Indian Ocean, while the negative phase is characterized by a reversed SST anomaly pattern. On the other hand, the normal Pacific Ocean has warm (cool) waters over the western (eastern) parts. Positive (negative) SST anomalies over the central/eastern (western) Pacific Ocean characterize the E1 Nino phenomenon. The reverse situation leads to the La Nina phenomenon. The coupled ocean-atmosphere phenomenon over the Pacific is referred to as the E1 Nino Southern Oscillation (ENSO) phenomenon. In this study the impact of IODM and ENSO on the East Asian monsoon variability has been studied using observational data and using the Community Atmospheric Model (CAM) of the National Center for Atmospheric Research (NCAR). Five sets of model experiments were performed with anomalous SST patterns associated with IODM/ENSO superimposed on the climatological SSTs. The empirical and dynamic approaches reveal that it takes about 3-4 seasons fur the peak IODM mode to influence the summer monsoon activity over East Asia. On the other hand, the impact of ENSO on the East Asian monsoon could occur simultaneously. Further, the negative (positive) phase of IODM and E1 Nino (La Nina) over the Pacific enhances (suppresses) monsoon activity over the Korea-Japan Sector. Alternatively, IODM appears to have no significant impact on monsoon variability over China. However, El Nino (La Nina) suppresses (enhances) monsoon activity over China. While the IODM appears to influence the North Pacific subtropical high, ENSO appears to influence the Aleutian low over the northwest Pacific. Thus, the moisture supply towards East Asia from the Pacific is determined by the strengthening/weakening of the subtropical high and the Aleutian low.

• Radiation Oncology Journal
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• v.16 no.4
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• pp.497-504
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• 1998

Purpose : To evaluate the usefulness of electronic portal imaging device through objective compare of the images acquired using an EPID and a conventional port film Materials and Methods : From Apr. to Oct. 1997, a total of 150 sets of images from 20 patients who received radiation therapy in the pelvis area were evaluated in the Inha University Hospital and Severance Hospital. A dual image recording technique was devised to obtain both electronic portal images and port film images simultaneously with one treatment course. We did not perform double exposure five to ten images were acquired from each patient. All images were acquired from posteroanterior (PA) view except images from two patients. A dose rate of 100-300 Mu/min and a 10-MV X-ray beam were used and 2-10 MUs were required to produce a verification image during treatment. Kodak diagnostic film with metal/film imaging cassette which was located on the top of the EPID detector was used for the port film. The source to detector distance was 140 cm. Eight anatomical landmarks (pelvic brim, sacrum, acetabulum. iliopectineal line, symphysis, ischium, obturator foramen, sacroiliac joint) were assessed. Four radiation oncologist joined to evaluate each image. The individual landmarks in the port film or in the EPID were rated - very clear (1), clear (2), visible (3), not clear (4), not visible (5). Results : Using an video camera based EPID system. there was no difference of image quality between no enhanced EPID images and port film images. However, when we provided some change with window level for the portal image, the visibility of the sacrum and obturator foramen was improved in the portal images than in the port film images. All anatomical landmarks were more visible in the portal images than in the port film when we applied the CLAHE mode enhancement. The images acquired using an matrix ion chamber type EPID were also improved image qualify after window level adjustment. Conclusion : The quality of image acquired using an electronic portal imaging device was comparable to that of the port film. When we used the enhance mode or window level adjustment. the image quality of the EPID was superior to that of the port film. EPID may replace the port film.