• Journal of Korea Water Resources Association
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• v.56 no.12
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• pp.969-980
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• 2023

Since the 2000s, ensemble streamflow prediction (ESP) has been actively utilized in South Korea, primarily for hydrological forecasting purposes. Despite its notable success in hydrological forecasting, the original objective of enhancing water resources system management has been relatively overlooked. Consequently, this study aims to demonstrate the utility of ESP in water resources management by creating a simple hypothetical exercise for dam operators and applying it to actual multi-purpose dams in South Korea. The hypothetical exercise showed that even when the means of ESP are identical, different costs can result from varying standard deviations. Subsequently, using sampling stochastic dynamic programming (SSDP) and considering the capacity-inflow ratio (CIR), optimal release patterns were derived for Soyang Dam (CIR = 1.345) and Chungju Dam (CIR = 0.563) based on types W and P. For this analysis, Type W was defined with standard deviation equal to the mean inflow, and Type P with standard deviation ten times of the mean inflow. Simulated operations were conducted from 2020 to 2022 using the derived optimal releases. The results indicate that in the case of Dam Chungju, more aggressive optimal release patterns were derived under types with smaller standard deviations, and the simulated operations demonstrated satisfactory outcomes. Similarly, Soyang Dam exhibited similar results in terms of optimal release, but there was no significant difference in the simulation between types W and P due to its large CIR. Ultimately, this study highlights that even with the same mean values, the standard deviation of ESP impacts optimal release patterns and outcomes in simulation. Additionally, it underscores that systems with smaller CIRs are more sensitive to such uncertainties. Based on these findings, there is potential for improvements in South Korea's current operational practices, which rely solely on single representative values for water resources management.

• Korean Journal of Clinical Laboratory Science
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• v.55 no.4
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• pp.291-297
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• 2023

Gastritis is an inflammation of the gastric mucosa and gastric ulcers are a break in the mucosa of the stomach lining. Past research on gastritis and gastric ulcers has been mainly conducted from the perspective that environmental factors are the primary cause of these gastric diseases. However, recently the importance of genetic factors has been emphasized due to current developments in genetic research. The SLC25A26 gene is believed to be associated with the accumulation of reactive oxygen species. Oxidative stress promotes an inflammatory response, which increases the production of free radicals and causes cellular damage, and these lead to the development of gastric diseases. In this study, the correlation between SLC25A26 and gastric diseases was analyzed. Polymorphisms in SLC25A26 were analyzed in 1,369 domestic gastric disease patients and 7,471 healthy controls. As a result, 11 single nucleotide polymorphisms (SNPs) (in the genotype) and 13 SNPs (in the imputation) showed statistical significance (P<0.05), and high relative risk of gastric diseases. Among them, the rs13874 allele of SLC25A26 showed a highly significant association with gastric diseases. In the genotype-based mRNA expression analysis, the minor allele (C) group showed increased mRNA expression and this could increase oxidative stress. In conclusion, SLC25A26 polymorphisms are associated with gastric diseases. These results may provide a basis for new guidelines for gastric disease management in the Korean population.

• Journal of Applied Biological Chemistry
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• v.66
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• pp.39-45
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• 2023

Biorenovation is a biotransformation method that converts the structure of chemical compounds and natural product through biocatalytic metabolism of microorganism and could enhance biological effectiveness and mitigate cytotoxicity compared to its substrates. Althaea rosea L. has been used as oriental medicine and is known for physiological efficacies such as antiurolithiatic, anti-inflammatory, and anti-cancer activities. A. rosea L. callus, the plant tissue grown to protect its wound, has been reported to have antioxidant and whitening effects. However, mechanisms of its other activity such as inflammation have not yet been investigated. In this study, we extracted A. rosea L. callus (AR) and produced biorenovated AR (ARBR), and then analyzed anti-inflammatory effect in Lipopolysaccharide-induced RAW 264.7 macrophage at 50, 100, 200 ㎍/mL of ARBR. As a result of inhibition test of nitric oxide production, it was found that ARBR was superior to AR without apparent toxicity. Furthermore, ARBR significantly inhibited production of prostaglandin E₂, inducible nitric oxide synthase, cyclooxygenase-2 and pro-inflammatory cytokines including Tumor necrosis factor-α, Interleukin-6, Interleukin-1β in a concentration-dependent manner. In conclusion, we suggest that ARBR could regulate the excessive inflammatory response to an appropriate level and be a promising material for functional cosmetics and pharmaceuticals.

• Land and Housing Review
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• v.15 no.1
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• pp.167-177
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• 2024

This study aimed to assess the efficacy of an adsorption process in removing organic matter and micropollutant residuals. After a full-scale water circulation system, the adsorption process was considered a post-treatment step. The system, treating anthropogenically impacted surface waters, comprises a hydro-cyclone, coagulation, flocculation, and dissolved air flotation unit. While the system generally maintained stable and satisfactory effluent quality standards over months, it did not meet the highest standard for organic matter (as determined by chemical oxygen demands). Adsorption experiments utilized two granular activated carbon types, GAC 830 and GCN 830, derived from coal and coconut-shell feedstocks, respectively. The assessment encompassed organic materials along with two notable micropollutants: acetaminophen (APAP) and acid orange 7 (AO7). Adsorption kinetics and isotherm experiments were conducted to determine adsorption rates and maximum adsorption amounts. The quantitative findings derived from pseudo-second-order kinetics and Langmuir isotherm models suggest the effectiveness of the adsorption process. The findings of this study propose the potential of employing the adsorption process as a post-treatment to enhance the treatment of contaminants that are not satisfactorily treated by conventional water circulation systems. This enhancement is crucial for ensuring the sustainability of urban water cycles.

• Journal of KIISE:Computer Systems and Theory
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• v.34 no.10
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• pp.493-501
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• 2007

The imprecise real-time system provides flexibility in scheduling time-critical tasks. Most scheduling problems of satisfying both 0/1 constraint and timing constraints, while the total error is minimized, are NP-complete when the optional tasks have arbitrary processing times. Liu suggested a reasonable strategy of scheduling tasks with the 0/1 constraint on uniprocessors for minimizing the total error. Song et at suggested a reasonable strategy of scheduling tasks with the 0/1 constraint on multiprocessors for minimizing the total error. But, these algorithms are all off-line algorithms. In the online scheduling, the NORA algorithm can find a schedule with the minimum total error for the imprecise online task system. In NORA algorithm, EDF strategy is adopted in the optional scheduling. On the other hand, for the task system with 0/1 constraint, EDF_Scheduling may not be optimal in the sense that the total error is minimized. Furthermore, when the optional tasks are scheduled in the ascending order of their required processing times, NORA algorithm which EDF strategy is adopted may not produce minimum total error. Therefore, in this paper, an online algorithm is proposed to minimize total error for the imprecise task system with 0/1 constraint. Then, to compare the performance between the proposed algorithm and NORA algorithm, a series of experiments are performed. As a conseqence of the performance comparison between two algorithms, it has been concluded that the proposed algorithm can produce similar total error to NORA algorithm when the optional tasks are scheduled in the random order of their required processing times but, the proposed algorithm can produce less total error than NORA algorithm especially when the optional tasks are scheduled in the ascending order of their required processing times.

• Pediatric Infection and Vaccine
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• v.19 no.3
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• pp.121-130
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• 2012

Purpose : The purpose of this study is to investigate clinical features and causative organisms in febrile infants younger than three months, to help identification of high risk patients for serious bacterial infection (SBI). Methods : A total of 313 febrile infants younger than three months, who had visited Seoul National University Children's Hospital from January 2008 to December 2010 were included. Clinical features, laboratory findings, causative organisms, and risk factors of SBI were analyzed by retrospective chart review. Causative bacterial or viral pathogens were identified by gram stain and cultures, rapid antigen tests, or the polymerase chain reaction from clinically reliable sources. Results : Among 313 infants, etiologic organisms were identified in 127 cases (40.6%). Among 39 cases of bacterial infections, Escherichia coli (66.7%) and Streptococcus agalactiae (12.8%) were common. Enterovirus (33.7%), respiratory syncytial virus (19.8%), and rhinovirus (18.8%) were frequently detected in 88 cases of viral infection. Patients with SBI (39 cases) showed significantly higher values of the white blood cell count ($14,473{\pm}6,824/mm^3$ vs. $11,254{\pm}5,775/mm^3$, P=0.002) and the C-reactive protein ($6.32{\pm}8.51mg/L$ vs. $1.28{\pm}2.35mg/L$, P<0.001) than those without SBI (274 cases). The clinical risk factors for SBI were the male (OR 3.7, 95% CI 1.5-8.9), the presence of neurologic symptoms (OR 4.8, 95% CI 1.4-16.8), and the absence of family members with respiratory symptoms (OR 3.6, 95% CI 1.2-11.3). Conclusion : This study identified common pathogens and risk factors for SBI in febrile infants younger than three months. These findings may be useful to guide management of febrile young infants.

• Radiation Oncology Journal
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• v.27 no.2
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• pp.78-83
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• 2009

Purpose: To examine the effect of suboptimal chemotherapy in patients undergoing preoperative chemoradiotherapy for the treatment of rectal cancer. Materials and Methods: The medical records of 43 patients who received preoperative concurrent chemoradiotherapy, followed by radical surgery for the treatment of pathologically proven adenocarcinoma of the rectum from April 2003 to April 2006 were retrospectively reviewed. The delivered radiation dose ranged from 41.4 to 50.4 Gy. The standard group consisted of patients receiving two cycles of a 5-FU bolus injection for three days on the first and fifth week of radiotherapy or twice daily with capecitabine. The standard group included six patients for each regimen. The non-standard group consisted of patients receiving one cycle of 5-FU bolus injection for three days on the first week of radiotherapy. The non-standard group included 31 patients. Radical surgery was performed at a median of 58 days after the end of radiotherapy. A low anterior resection was performed in 36 patients, whereas an abdominoperineal resection was performed in 7 patients. Results: No significant difference was observed between the groups with respect to pathologic responses ranging from grades 3 to 5 (83.3% vs. 67.7%, p=0.456), downstaging (75.0% vs. 67.7%, p=0.727), and a radial resection margin greater than 2 mm (66.7% vs. 83.9%, p=0.237). The sphincter-saving surgery rate in low-lying rectal cancers was lower in the non-standard group (100% vs. 75%, p=0.068). There was no grade 3 or higher toxicity observed in all patients. Conclusion: Considering that the sphincter-saving surgery rate in low-lying rectal cancer was marginally lower for patients treated with non-standard, suboptimal chemotherapy, and that toxicity higher than grade 2 was not observed in the both groups, suboptimal chemotherapy should be avoided in this setting.

• Journal of the Korea Organic Resources Recycling Association
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• v.24 no.1
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• pp.21-29
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• 2016

We mix food waste leachate and sewage sludge by the proportion of 1:9, 3:7 and 5:5. It turns out that they produced 233, 298 and 344 $CH_4{\cdot}mL/g{\cdot}VS$ of methane gas. The result suggests that as the mixing rate of food waste leachate rises, the methane gas productions increases as well. And more methane gas is made when co-digesting sewage sludge and food waste leachate based on the mixing ratio, rather than digesting only sewage sludge alone. Modified Gompertz and Exponential Model describe the BMP test results that show how methane gas are produced from organic waste. According to the test, higher the mixing rate of food waste leachate is, higher the methane gas productions is. The mixing ratio of food waste leachate that produces the largest volume of methane gas is 3:7. Modified Gompertz model and Exponential model describe the test results very well. The correlation values($R^2$) that show how the results of model prediction and experiment are close is 0.92 to 0.98.

• Journal of Chest Surgery
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• v.30 no.7
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• pp.677-685
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• 1997

Thromboelastography(TEG) is the unique measure that gives rapid information about the whole clotting process. Simplifying the diagnosis of coagulopathy during operations, TEG can provide an adequate therapy for postoperative bleeding. Remarkable improvement in hemostasis after cardiopulmonary bypass(CPB) has been achieved by the treatment with proteinase inhibitor aprotinin, but the hemostatic mechanism of aprotinin during CPB is still unclear. This study was designed to evaluate the effects of aprotinin on coagulation system during CPB by using TEG. Forty patients who underwent CPB were divided into two groups: aprotinin(2u 106 kallikrein inhibition units, as a single dose into the cardiopulmonary bypass priming solution) treatment group(male 14, female 8, mean age=50.Byears) and no aprotinin treatment(control) group(male 10, female 8, mean age=53.4 years). TEG, activated clotting time, prothrombin time, activated partial thromboplastin time, platelet counts, fibrinogen an (ibrinogen degradation product(FDP) concentrations were checked before and after CPB(30 minutes after neutralization of heparin effect by protamine sulfate). There was no significant difference in other conventional coagulation tests of two groups except postcardiopulmonary bypass FDP concentration in control group, which was significantly increased compared to that in aprotinin group(p<0.05). In TEG variables of both groups, clot formation time(K) and alpha $angle(\alpha^{\circ})$ were significantly increased and decreased, respectively, after CPB(p<0.05), but fibrinolytic index(LYS60) was not changed during CPB. In aprotinin group, reaction time(R) was decreased significantly after CPB(p<0.05) but maximum amplitude(MA) was not changed(p>0.05). On the contrary, R was not changed markedly but MA was decreased significantly in control group after CPB(p<0.05). This result shows that main change in coagulation system during CPB is not hyperfibrinolysis but cecrease in clot strength by platelet dys unction, and the main effect of aprotinin during cardiopulmonary bypass is the maintenance of clot strength to the pre-CPB level by the preservation of platelet function.

• Journal of the Mineralogical Society of Korea
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• v.20 no.3
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• pp.147-153
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• 2007

Kaolinite [$Al_2Si_2O_5(OH)_4$] was successfully synthesized by a hydrothermal process from amorphous $Al(OH)_3$ and $SiO_2$ at $230^{\circ}C$ under the pressure of $30 kg/cm^2$. The experiments were performed varying temperatures ($180{\sim}280^{\circ}C$), pressure ($10{\sim}60kg/cm^2$), chemistry ($Al_2O_3/SiO_2 = 0.5{\sim}0.38$) and pH ($0.3{\sim}9.5$) of the solution. The autoclaving was carried out in a closed stainless steel vessel. Kaolinite appears from the starting composition of $Al_2O_3/SiO_2= 0.5$ with boehmite and was stable as a single phase with the composition of $Al_2O_3/SiO_2=0.45$. Boehmite was a stable phase below $200^{\circ}C$ for the 240 h period of autoclaving, but kaolinite appeared even in 20 h at $230^{\circ}C$. The single kaolinite phase of a good crystallinity was observed at pH ranging 2 to 6. That indicates that pH is one of the most critical parameters for the successful formation of kaolinite. The optimal molar ratio of $Al_2O_3$ to $SiO_2$ was determined to be 0.45. The XRD pattern of the synthesized kaolinite coincided with that of natural one and its morphology was the cluster type of the kaolinite crystals (diameter = ${\sim}3{\mu}m$), irrespective of starting material, composition and temperature.