• Journal of the Korean Association of Geographic Information Studies
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• v.5 no.2
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• pp.1-15
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• 2002

Atmospheric aerosols interact with sunlight and affect the global radiation balance that can cause climate change through direct and indirect radiative forcing. Because of the spatial and temporal uncertainty of aerosols in atmosphere, aerosol characteristics are not considered through GCMs (General Circulation Model). Therefor it is important physical and optical characteristics should be evaluated to assess climate change and radiative effect by atmospheric aerosols. In this study GMS-5 satellite data and surface measurement data were analyzed using a radiative transfer model for the Yellow Sand event of April 7~8, 2000 in order to investigate the atmospheric radiative effects of Yellow Sand aerosols, MODTRAN3 simulation results enable to inform the relation between satellite channel albedo and aerosol optical thickness(AOT). From this relation AOT was retreived from GMS-5 visible channel. The variance observations of satellite images enable remote sensing of the Yellow Sand particles. Back trajectory analysis was performed to track the air mass from the Gobi desert passing through Korean peninsular with high AOT value measured by ground based measurement. The comparison GMS-5 AOT to ground measured RSR aerosol optical depth(AOD) show that for Yellow Sand aerosols, the albedo measured over ocean surfaces can be used to obtain the aerosol optical thickness using appropriate aerosol model within an error of about 10%. In addition, LIDAR network measurements and backward trajectory model showed characteristics and appearance of Yellow Sand during Yellow Sand events. These data will be good supporting for monitoring of Yellow Sand aerosols.

• Korean Chemical Engineering Research
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• v.50 no.6
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• pp.1034-1042
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• 2012

This study was performed by using an LFR (laminar flow reactor), which can be used to carry out different types of research on coal. In this study, an LFR was used to analyze coal flames, tar and soot yields, and structures of chars for two coals depending on their volatile content. The results show that the volatile content and oxygen concentration have a significant effect on the length and width of the soot cloud and that the length and width of the cloud under combustion conditions are less than those under a pyrolysis atmosphere. At sampling heights until 50 mm, the tar and soot yields of Berau (sub-bituminous) coal, which contains a large amount of volatile matter, are less than those of Glencore A.P. (bituminous) coal because tar is oxidized by the intrinsic oxygen component of coal and by radicals such as OH-. On the other hand, at sampling heights above 50 mm, the tar and soot yields of Berau coal are higher than those of Glencore A.P. coal by reacted residual volatile matter, tar and light gas in char and flame. With above results, it is confirmed that the volatile matter content and the intrinsic oxygen component in a coal are significant parameters for length and width of the soot cloud and yields of the soot. In addition, the B.E.T. results and the images of samples (SEM) obtained from the particle separation system of the sampling probe support the above results pertaining to the yields; the results also confirm the pore development on the char surface caused by devolatilization.

• Journal of Gastric Cancer
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• v.7 no.4
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• pp.213-218
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• 2007

Purpose: Laparoscopy-assisted distal gastrectomy (LADG) is gaining wider acceptance for the treatment of early gastric cancer. However, firm evidence supporting the long-term outcome after LADG for gastric cancer is unknown. This study compared long-term quality of life after LADG versus an open distal gastrectomy (ODG) for early gastric cancer. Methods: This study included 29 patients who underwent LADG and 57 patients who underwent ODG for the treatment of stage I gastric cancer. Quality of life was evaluated based on the Korean version of EORTC QLQ-C30 (version 3.0) and EORTC QLQ-STO22 one year after surgery. All patients underwent a Billroth II gastrectomy for stage I gastric cancer between January 2003 and December 2004. Results: A total of 86 (58%) out of 154 patients responded to the questionnaire. Demographic features showed no difference between the two groups of patients for age, sex, depth of invasion, lymph node metastasis except for tumor size and the number of retrieved lymph nodes. The mean score for global health status was not statistically different (LADG, $60.3{\pm}20.4$ vs ODG, $57{\pm}20.6$; P=0.413). The total score of 21 items related to stomach cancer (EORTC QLQ-STO22) also was not statistically different (LADG, $68.9{\pm}64.9$ vs ODG, $94.5{\pm}97.3$; P=0.340). Conclusion: Based on the results of the Korean version of EORTC QLQ-C 30 (version 3.0) and EORTC. QLQ-STO22, LADG does not seem to have any long-term benefit over ODG on 'quality of life'.

• Clinical and Experimental Pediatrics
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• v.49 no.3
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• pp.268-272
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• 2006

Purpose : The reinfection rate of H. pylori reported before $^{13}C$-urea breath test($^{13}C$-UBT) era was higher than that of the post $^{13}C$-UBT era. Children are usually reluctant to receive invasive endoscopic evaluation for the reinfection of H. pylori, particularly when they are asymptomatic. The aim of the study is to discover the reinfection rate by different diagnostic tests, and to find out what causes the difference. Methods : Children confirmed to be eradicated from H. pylori were included in the study. Reinfection was evaluated by endoscopic biopsy based tests(n=34, mean age $11.5{\pm}3.7$ years) and/or a $^{13}C$-UBT(n=38, mean age $10.0{\pm}3.6$ years) at the time of 18 months after eradication. At first visit, H. pylori infection had been diagnosed by positive results from a rapid urease test, Giemsa stain and Warthin-Starry stain and/or a positive culture. Eradication was defined as negative results from all above tests 1-3 months after eradication therapy. Results : Reinfection rate by endoscopic biopsy based tests was 35.3 percent(12/34). All patients had abdominal symptoms(P=0.000). Reinfection rate was 13.2 percent(5/38) by a $^{13}C$-UBT. Reinfection rate was higher in children with abdominal symptoms(P=0.008). There was no evidence that reinfection rate depended on the sex(P=0.694), age(P=0.827), diseases(peptic ulcers vs gastritis, P=0.730) and eradication regimen(P=0.087). Conclusion : Helocibacter pylori reinfection rate in Korean children was 13.2 percent per 18 months by a non-invasive test or $^{13}C$-UBT. Accurate determinations of the reinfection rate in children is affected by the compliance of the diagnostic tests. Non-invasive tests should be considered to investigate the reinfection rate in children.

• Journal of Korean Tunnelling and Underground Space Association
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• v.22 no.4
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• pp.347-365
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• 2020

In order to resolve traffic problems in urban areas and to increase the area of green spaces, tunnels in downtown areas are being increased. Additionally, the application of large port smoke extraction ventilation systems is increasing as a countermeasure to smoke extraction ventilation for tunnels with high potential for traffic congestion. It is known that the smoke extraction performance of the large port smoke extraction system is influenced not only by the amount of the extraction flow rate, but also by various factors such as the shape of the extraction port (damper) and the extraction air velocity through a damper. Therefore, in this study, the design standards and installation status of each country were investigated. When the extraction air flow rate was the same, the smoke extraction performance according to the size of the damper was numerically simulated in terms of smoke propagation distance, compared and evaluated, and the following results were obtained. As the cross-sectional area of the smoke damper increases, the extraction flow rate is concentrated in the damper close to the extraction fan, and the smoke extraction rate of the damper in downstream decreases, thereby increasing the smoke propagation distance on the downstream side. In order to prevent such a phenomenon, it is necessary to reduce the cross-sectional area of the smoke damper and increase the velocity of passing air through the damper so that the pressure loss passing through the damper increases, thereby reducing the non-uniformity of smoke extraction flow rate in the extraction section. In this analysis, it was found that when the interval distance of the extraction damper was 50 m, the air velocity passing through damper was 4.4 m/s or more, and when the interval distance of the extraction dampers was 100 m, the air velocity passing through damper was greater than 4.84 m/s, it was found to be advantageous to ensure smoke extraction performance.

• Korean Journal of Poultry Science
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• v.42 no.2
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• pp.147-156
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• 2015

This study was conducted to investigate the effects of dietary resveratrol on growth performance, blood biochemical parameters, immunoglobulin, and blood antioxidant activity in broiler chicks. Three hundred twenty one-day old broiler chicks were divided 8 treatments (C(-), basal diet; C(+), basal diet with antibiotics; DL-${\alpha}$-tocopherol 20 IU; DL-${\alpha}$-tocopherol 200 IU; resveratrol 20 ppm; resveratrol 200 ppm; methylated resveratrol 20 ppm; methylated resveratrol 200 ppm) with 4 replicates and 10 birds per replicate. Birds were reared for 35 days, and, at the age of 35 days, eight birds of average weight from each replicate were selected for blood samples collection. There were no significant differences on feed intake and feed conversion ratio. But final body weight and weight gain in antibiotics, resveratrol and methylated resveratrol treatments were significantly higher than no-antibiotics and ${\alpha}$-tocopherol treatments (P<0.05). There were no significant differences on carcass rate and relative organ weights among treatments, however, weights of liver and bursa of februcius in antibiotics, resveratrol and methylated resveratrol treatment were lower than other treatments. Weight of pancreas was high in resveratrol and methylated treatment. On the cecal microflora (total microbes, Coliform bacteria, Salmonella spp., and lactic acid bacteria), these in resveratrol and methylated resveratrol treatments didn't show the differences compared with those in no-antibiotics, antibiotics, and ${\alpha}$-tocopherol treatments. In the serum, there were no significant differences on creatinine, blood urea nitrogen (BUN), total protein, albumin, globulin, alanine aminotransferase (ALT) and aspartate aminotransferase (AST) among treatments, though globulin contents of reseveratrol 200 ppm and methylated resveratrol 20 ppm treatments decreased compared to those of other treatments. Immunoglobulin (IgA, IgG and IgM) were significantly decreased in antibiotics and resveratrol treatments compared to that of no-antibiotics and ${\alpha}$-tocopherol treatments (P<0.05). Superoxide dismutase (SOD) like activity tended to increase in resveratrol groups (P<0.05), however, there was no significant difference on malondiakdehyde (MDA) content among treatments. In conclusion, these results showed that resveratrol derived from mulberry can be used as alternative of antibiotics through improvement of broiler's performance and maintain of health.

• Pediatric Infection and Vaccine
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• v.17 no.1
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• pp.36-48
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• 2010

Purpose : In children on anticancer chemotherapy, bloodstream infections (BSIs) are a major cause of morbidity and mortality. We investigated febrile episodes and bloodstream infections in pediatric cancer patients to guide proper selection of empiric antibiotics for febrile pediatric hemato-oncologic patients. Methods : All febrile episodes treated in the division of hematology-oncology, the department of pediatrics, Hanyang University Hospital, between July 2005 and June 2008 were reviewed. Episodes with and without bloodstream infections were compared. Results : Forty cases (18.9%, 25 patients) of BSI occurred in 212 febrile episodes (63 patients). Thirty-seven cases (23.6%, 22 patients) of BSI occurred in 157 febrile episodes with neutropenia (54 patients). Microorganisms identified in BSI corresponded to 23 gram-positive bacteria (51.2%), 20 gram-negative bacteria (44.5%), and 2 fungi (4.4%). Rates of BSI between those who had received umbilical cord blood transplantation and those who had received transplantation from other source were significantly different (55.0% vs. 7.7%, P =0.001). No differences in mortality rate were observed among organisms in BSI patients. For febrile episodes the rate of BSI was higher among those with Chemoport than those with Hickman catheter (P =0.029) and gram-positive pathogens were more likely to be associated with Chemoport (P =0.001). Conclusion : The study showed the rate of BSI, distribution of pathogens with regard to neutropenia, transplantation, central venous catheters, and antimicrobial susceptibility of pathogens in order to help guide in the choice of optimal empiric antibiotics in pediatric febrile neutropenic hemato-oncologic patients.

• Clinical and Experimental Pediatrics
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• v.48 no.12
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• pp.1370-1377
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• 2005

Purpose : Delineation of serum lipid and lipoprotein values in children after Kawasaki disease(KD) is important because of the predilection of this disease for the coronary arteries. Methods : The KD group was composed of 51 patients who were hospitalized from Jan. 2002 to Dec. 2003. Control was 25 patients with non-KD febrile illness. The levels of total lipid, phospholipid, triglyceride, HDL-cholesterol(HDL-C), LDL-cholesterol, total cholesterol, apolipoprotein A1(apo A1), apolipoprotein B, and Lipoprotein(a) were measured and compared with Echocardiographic findings. Measurements were obtained in four time periods: acute febrile, subacute, convalescent phase and 1 year after KD. Results : HDL-C($33.64{\pm}7.49mg/dL$ vs $50.43{\pm}14.41mg/dL$, P<0.01) and apo A1($99.75{\pm}6.39mg/dL$ vs $113.34{\pm}11.35mg/dL$, P<0.05) were decreased more in the acute febrile period of KD than in the control, but these changes were not correlated with cardiac complications. All lipid profiles were markedly elevated in the subacute stage and normalized in the convalescent stage; there were no changes until 1-year follow up. There were no significant differences in the changes of lipid profiles, including Lp(a) and coronary dilatation, in any time periods. Conclusion : KD is associated with important abnormalities in lipid metabolism, but these changes were transient and appear to be due to the disease itself. These data lead us to infer that KD dose not cause such permanent changes in lipid abnormalities as to be considered a risk factor for atherosclerosis, beyond that caused by the disease itself.

• Clinical and Experimental Pediatrics
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• v.53 no.4
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• pp.560-564
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• 2010

Purpose : Electroencephalography (EEG) findings can play a critical role in a variety of decisions, including initiation and withdrawal of antiepileptic drugs (AEDs) therapy. Interictal epileptiform discharges (IEDs) are predictor of recurrent seizures. We investigated IEDs in EEG after AED therapy and related factors in epileptic children. Methods : The subjects were 257 children [151 males and 106 females; age, 6.79 (3.40) years; duration of therapy, 2.48 (1.85) years] diagnosed with epilepsy at the Department of Pediatrics, Pusan National University Hospital between January 2001 and December 2007, who received AEDs for more than 6 months. EEG was performed at the intervals of 6-12 months. We divided patients into 4 groups according to IED detection before and after AEDs treatment. Related clinical factors, including gender, age at the start of treatment, seizure type, cause of seizure, AED frequency, seizure control, duration of AED therapy, and background activity were investigated in the 4 groups. Results : Generalized epilepsy was relatively frequen in patients who did not show IEDs in last follow-up EEG. There were no clinically significant differences according to gender, age at the start of treatment, cause of seizure, AED frequency, seizure control, duration of AED medication, and background activity in the 4 groups ($P$>0.05). Conclusion : IEDs changed after AED treatment in one-third of the patients. Generalized epilepsy is positive factor for negative IEDs in last follow-up EEG.

• Clinical and Experimental Pediatrics
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• v.50 no.10
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• pp.959-964
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• 2007

Purpose : The purpose was to investigate the clinical considerations of patients affected by meconium aspiration syndrome (MAS) and the effect of suctioning through endotracheal intubation immediately after delivery on the prognosis of MAS. Methods : A total of 44 inpatients diagnosed as MAS in the Neonatal Intensive Care Unit (NICU) at Cheil Hospital were selected from January 2004 to June 2006. They were divided into two groups. In the early aspiration group (12 patients), suctioning through endotracheal intubation was performed according to the neonatal resuscitation program of the American Academy of Pediatrics and the American Heart Association because infants born through meconium-stained amniotic fluid (MSAF) were not vigorous after birth. In the early non-aspiration group (32 patients), endotracheal intubation was not performed because the infants born through MSAF were vigorous after birth. These two groups were analyzed retrospectively by medical records in the fields of clinical features, obstetric risk factors, complications, treatment, and duration of hospitalization. Results : There was no significant difference in mean gestational age, mean birth weight, sex, and delivery mode between the early aspiration group and the early non-aspiration group. Mean Apgar score of the early aspiration group both in 1 and 5 minute score was significantly lower than in the early non-aspiration group. Lengths of hospitalization and duration of mechanical ventilator care were longer in the early non-aspiration group, but there was no significant difference. Total duration of oxygen therapy was significantly longer in the early non-aspiration group than in the early aspiration group. Conclusion : In this study, the early non-aspiration group used surfactant more and had a longer duration of mechanical ventilator and hospitalization, but there was no significant difference. Total duration of oxygen therapy was significantly longer in the early non-aspiration group. Therefore, more detailed guidelines for vigorous infants born through MSAF are needed and we should study and follow up the long term prognosis of neurological complications of MAS.