• Journal of the korean academy of Pediatric Dentistry
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• v.34 no.3
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• pp.420-429
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• 2007

The purpose of this study was to compare the micro ensile bond strength to bovine dentin of several adhesives (SM, Scotch $Bond^{TM}$ Multipurpose; SB, $Adper^{TM}$ Single Bond 2; SE, $Clearfil^{(R)}$ SE Bond; AQ, AQ $Bond^{TM}$; TS, $Clearfil^{(R)}$ tri-S Bond). Except SM and SB, they have a simplified one- or two-step application protocols in compare with the dentin adhesives conventional three-step protocols. For the microtensile bond strength test, the labial surfaces of bovine incisors were used. Following exposure of dentin layer, according to their manufacturer's directions, each dentin adhesives were applied and composite resin blocks were constructed. The teeth were sectioned for specimen and tested microtensile bond strength. Also observed the fracture mode of interface. The obtained results were as follows : 1. The microtensile bond strength values ranged from 51.34 to 24.04 MPa on dentin(in decreasing order, SE, SM, SB, AQ and TS). 2. The highest microtensile bond strength was by SE and SM on bovine dentin, and the lowest by AQ and TS. 3. SM, SB and SE showed cohesive failures and adhesive failure but AQ, TS presented almost adhesive failures. In summary, microtensile bond strengths of single-step adhesives (AQ and TS) on bovine dentin were significantly lower than those of multi-step adhesives (SM, SB and SE) (p<0.05).

• Tuberculosis and Respiratory Diseases
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• v.64 no.2
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• pp.87-94
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• 2008

Background: Surveillance of TB drug resistance (DR) is essential for providing information on the magnitude and trends in resistance, for developing treatment guidelines and for monitoring the effect of interventions. Up to now national surveys of drug resistance of M. tuberculosis have been conducted four times since 1994 among patients registered at health centers. The purpose of this study is to estimate the prevalence of primary drug resistance among new cases identified in private sector, and to compare it with the previous national drug resistance surveys. Methods: The study collected results of drug susceptibility testing (DST) performed at the Korean Institute of Tuberculosis by the request of private sector from January 2003 to December 2005, and then finally selected new cases for the analysis from the database of Korean TB Surveillance (KTBS) by matching patients' name and social identification numbers. Results: Of the 5,132 new patients included in the study, 689 (13.4%) patients were found to have drug resistance at least one drug, 530 patients (10.3%) were isoniazid resistant, 195 patients (3.8%) were multi-drug resistant (MDR), and 21 patients (0.4%) were extensively drug resistant (XDR). The rate of drug resistance tended to decrease annually but it was not statistically significant. When compared with previous national DR surveys in 2003 and in 2004 respectively, they were not significantly different. Conclusion: The prevalence of DR among new cases managed in the private sector did not show significant difference from that of new patients registered in the public sector in the same year.

• Progress in Medical Physics
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• v.18 no.3
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• pp.179-185
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• 2007

The purpose of this study is to investigate the spectra of a magnetic resonance spectroscopy (MRS) in accordance with the variance of TE and the volumes of metabolites in a localized voxel for the quality assurance using a designed single voxel spectroscopy QA phantom. Because a cone-shade phantom is designed as the volume of metabolite in a localized voxel is changeable, we try to analyze the peaks of each metabolite (NAA, Cr, Cho, Lac, etc.) in accordance with metabolite volume in a localized voxel as well as echo time (TE). All data were obtained using a 3T MRI/MRS machine and analyzed using $jMRUI^{(R)}$. The results of this study show that TE is in inverse proportion to the noise of MRS and the longer TE and the less metabolite volume in the localized voxel, the peak intensities of each metabolite decrease. In case of the lactate, its peak was observed on the all TE only if the greatest metabolite is included in the localized voxel. Then, the intensity of a metabolite is more sensitive to the metabolite volume in the localized voxel than the TE. These obtained in vitro MRS data is provide the guideline that is important for in vivo metabolite quantification. But, in the edge of cone-shape vial air bubbles were observed and spectrum could not obtained. Therefore our cone-shape MRS phantom needs to be modified in order to solve these problems.

• Korean Journal of Ecology and Environment
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• v.40 no.1
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• pp.14-30
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• 2007

The purpose of this study was to evaluate trophic conditions of various Korean reservoirs using Trophic State Index (TSI) and predict the reservoir conditions by empirical models. The water quality dataset (2000, 2001) used here were obtained from the Ministry of Environment, Korea. The water quality, based on multi-parameters of dissolved oxygen (DO), biological oxygen demand (BOD), chemical oxygen demand (COD), total phosphorus (TP), total nitrogen (TN), suspended solid (SS), Secchi depth (SD), chlorophyll-${\alpha}$ (CHL), and conductivity largely varied depending on the sampling watersheds and seasons. In general, trophic conditions declined along the longitudinal axis of headwater-to-the dam and the largest seasonal variations occurred during the summer monsoon of July-August. Major inputs of TP occurred during the monsoon (r=0.656, p=0.002) and this pattern was similar to solid dynamics of SS (r=0.678, p<0.001). Trophic parameters including CHL, TP, SD, and TN were employed to evaluate how the water systems varies with season. Trophic State Index (TSI, Carlson, 1977), based on TSI (CHL), TSI (TP), and TSI (SD), ranged from mesotrophic to eutrophic. However, the trophic state, based on TSI (TN), indicated eutrophic-hypereutrophic conditions in the entire reservoirs, regardless of the seasons, indicating a N-rich system. Overall, nutrient data showed that phosphorus was a primary factor regulating the trophic state. The relationships between CHL (eutrophication index) vs. trophic parameters (TN, TP, and SD) were analysed to develop empirical models which can predict the trophic status. Regression analyses of log-transformed seasonal CHL against TP showed that the value of $R^2$ was 0.31 (p=0.017) in the premonsoon but was 0.69 (p<0.001) during the postmonsoon, indicating a greater algal response to the phosphorus during the postmonsoon. In contrast, SD had reverse relation with TP, CHL during all season. TN had weak relations with CHL during all seasons. Overall, data suggest that TP seems to be a good predictor for algal biomass, estimated by CHL, as shown in the empirical models.

• The Korean Journal of Nuclear Medicine Technology
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• v.14 no.2
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• pp.190-196
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• 2010

Purpose: This study was undertaken to investigate the feasibility of using automated liquid-handling systems equipped with reusable fixed tips in Radioimmunoassays and to demonstrate that the use of an automated pipetting instrument can decrease in the typical daily workload. Materials and Methods: The precisions of the automated pipettor and the manual pipettor were determined gravimetrically (n=30). A total of 30 specimens for HBs Ag were repeatedly pipetted (three replicates) with the automated pipettor and then retested. PSA samples were simultaneously pipetted with either the automated pipettor or the manual pipettor and then analyzed (n=40). Sample carryover test assessed for CA19-9, AFP and HCG when the automated pipettor was used. Pipetting speed of the automated pipettor and the manual pipettor were compared by evaluation of each workload. Results: The precisions coefficients of variation (CV) were 2.1% for the automated pipettor and 1.6% for manual pipettor. The mean cpm and CV for each group of replicates were 41,203 cpm and 3.7% for HBs Ag positive specimens, and 99 cpm and 7.9% for HBs Ag negative specimens, respectively. PSA results showed no significant differences between automated pipettor and manual pipettor (p=0.15, r=0.999). Carryover for CA19-9, AFP and HCG analytes was <0.1 ppm or below the assay limit of detection. Pipetting speed was significantly improved by using the automated instrument. Conclusion: There was no evidence that the use of an automated pipettor adversely affected any of the performance characteristics of the assay. Indeed, routine use of the Tecan automated pipettor has resulted in a decrease in the typical daily workload.

• Childhood Kidney Diseases
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• v.4 no.1
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• pp.6-10
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• 2000

Purpose: To evaluate whether the urinary creatinine concentration is a reliable reference value to standardize urinary solute excretion in a spot urine sample during the first week of life. Methods: Spontaneously voided urine specimens were obtained in 49 healthy full term neonates, and in 33 healthy older children with the median ages of $5.7{\pm}4.3$ years, two urine samples were available with an interval of 2 to 3 days. Urine creatinine concentration was determined by the Jaffe test(CoBAS, Integra, Roche, Swiss). Uurine osmolality was determined by the freezing point depression test(Multi-osmette, Precision, USA). Results: Mean urinary creatinine and osmolality values of the first urine samples were not significantly different with the second urine samples in each group. Mean urinary creatinine and osmolality values in neonates were significantly different from the older children of the each urine sample(P<0.01). In neonates, the mean of the urinary oreatinine/osmolality ratios was higher than that of the older children(P<0.01). The urinary creatinine and the creatinine/osmolality values of the first urine samples were closely correlated with those of the second samples in both two groups(P<0.001). Conclusion: The urinary creatinine concentration during the first day of life is relatively stable, even when corrected for urinary osmolality The urinary creatinine and the urinary creatinine/osmolality ratio, therefore, can be used to standardize the urinary excretion of solutes in the neonate.

• Pediatric Gastroenterology, Hepatology & Nutrition
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• v.12 no.1
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• pp.16-22
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• 2009

Purpose: To update the epidemiologic information of hepatobiliary diseases in pediatric inpatients using cross-sectional survey data throughout the Republic of Korea. Methods: Nationwide cross-sectional survey was obtained from the 85 residency training hospitals in Korea to gather the final diagnosis on discharge. The surveyed periods were from 2004 to 2006. All the reports regarding the diagnosis were based on ICD-10 system. In this study, we focused on hepatobiliary diseases. Results: A total of 826,896 cases with discharge data were collected, of which 4,151 (5.0%) hepatobiliary cases were identified; 2,385 cases (57.4%) of hepatobiliary disease were hepatitis, which was the most common hepatobiliary disease. Other diseases included congenital hepatobiliary diseases (524 cases [12.6%]) and biliary diseases (315 cases [7.6%]). The prevalence of hepatobiliary disease according to age differed. Biliary atresia was the most common hepatobiliary disease in the neonatal period, whereas the prevalence of hepatitis increased in adolescents. The total number of hepatobiliary operations was 416 cases. With the comparison of annual data, there was no definite difference in the total number of hepatobiliary cases. The average duration of hospital stay appeared to decrease gradually. Conclusion: In this study, we have summarized the recent epidemiology of hepatobiliary disorders in Korean children based on discharge data. Hepatobiliary disorders in pediatric inpatient units consisted of diverse disorders with a low prevalence, so multi-center approaches should be considered to enhance the clinical and public health outcomes. To improve this nationwide survey, a new data collecting system should be developed.

• Pediatric Infection and Vaccine
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• v.23 no.2
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• pp.102-108
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• 2016

Purpose: Kawasaki disease (KD) shows a variety of clinical signs of multi-system involvement, including clinical diagnostic criteria. It is unknown that the severity of the clinical signs is associated with the risk of coronary artery lesions (CALs). We wanted to evaluate clinical characteristics and the risk of CALs in the patient groups who had severe skin lesions or those with arthritis. Methods: We retrospectively reviewed the medical records of 220 KD patients who were treated with intravenous immunoglobulin (IVIG). We compared clinical and laboratory data between the group with severe skin lesions (n=52) and those with mild or no skin lesions (n=168), and between the group with arthritis (n=6) and those without arthritis (n=214). Results: The mean age of total patients was $2.23{\pm}1.87years$ of age, and the male-to-female ratio was 1.5:1 (138/82). Among 220 patients, 52 patients had CALs (23.6%), and 29 patients (13.2%) showed incomplete KD. The patients with CALs had a higher mean age, longer total fever duration, and higher rate of IVIG non-responsiveness. The patient group with severe skin lesions showed a higher mean age (P<0.001), more prolonged fever duration (P=0.041), higher frequency of CALs (P=0.033), higher WBC, neutrophil, and neutrophil-to-lymphocyte ratio levels, compared to the patient group without severe skin lesions. The patients with arthritis had a tendency of further treatment with methylprednisolone or infliximab. Conclusions: The frequency of CALs was higher in patient group with severe skin lesions. Our results suggest that the intensity of clinical signs of KD such as skin rash, cervical lymphadenopathy and possibly arthritis may be associated the risk of CALs.

• Pediatric Infection and Vaccine
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• v.23 no.1
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• pp.31-39
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• 2016

Purpose: The aim of this study was to investigate the prognostic factors for Pneumocystis jirovecii pneumonia (PCP) and to evaluate the influence of PCP prophylaxis in pediatric patients. Methods: From January 2002 to April 2015, patients aged <18 years with a diagnosis of confirmed PCP at our institute were reviewed retrospectively. Clinical characteristics and outcomes were compared according to the groups with or without PCP prophylaxis. Risk factors associated with PCP-related death were analyzed by logistic regression analysis. Results: During study period, a total of 24 patients were diagnosed with PCP by immunofluorescence assay and/or PCR. The median age of the patients was 5 years (range, 3 months-18 years) and 23 (96%) had immunocompromised conditions including hematologic disorders with or without hematopoietic stem cell transplantation (n=15), solid organ transplantation (n=4), and primary immune deficiency (n=4). Most common presenting symptoms were tachypnea and cough (92%, each). At the time of diagnosis, 79% (19/24) and 25% (6/24) suffered from respiratory failure and multi-organ dysfunction syndrome (MODS), respectively. Mechanical ventilation was required in 8 (33%) patients and 5 (21%) patients died of PCP. Multivariate analysis showed that MODS at initial presentation was an indicator of poor prognosis (OR, 17.1 [95% CI 1.13-257.67]; P=0.04). Compared to the patients without PCP prophylaxis, the frequency of MODS at diagnosis, need for mechanical ventilation and length of hospital days were significantly less common in the children who received PCP prophylaxis. Conclusions: MODS at presentation was a significant predictor for poor outcome and PCP prophylaxis could alleviate the clinical courses of pediatric PCP. Prospective study will be mandatory to determine the risk factors for development and deterioration of PCP in children.

• Korean Journal of Remote Sensing
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• v.34 no.5
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• pp.811-827
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• 2018

The purpose of this study is to compare machine learning algorithm and deep learning algorithm in crop classification using multi-temporal remote sensing data. For this, impacts of machine learning and deep learning algorithms on (a) hyper-parameter and (2) training sample size were compared and analyzed for Haenam-gun, Korea and Illinois State, USA. In the comparison experiment, support vector machine (SVM) was applied as machine learning algorithm and convolutional neural network (CNN) was applied as deep learning algorithm. In particular, 2D-CNN considering 2-dimensional spatial information and 3D-CNN with extended time dimension from 2D-CNN were applied as CNN. As a result of the experiment, it was found that the hyper-parameter values of CNN, considering various hyper-parameter, defined in the two study areas were similar compared with SVM. Based on this result, although it takes much time to optimize the model in CNN, it is considered that it is possible to apply transfer learning that can extend optimized CNN model to other regions. Then, in the experiment results with various training sample size, the impact of that on CNN was larger than SVM. In particular, this impact was exaggerated in Illinois State with heterogeneous spatial patterns. In addition, the lowest classification performance of 3D-CNN was presented in Illinois State, which is considered to be due to over-fitting as complexity of the model. That is, the classification performance was relatively degraded due to heterogeneous patterns and noise effect of input data, although the training accuracy of 3D-CNN model was high. This result simply that a proper classification algorithms should be selected considering spatial characteristics of study areas. Also, a large amount of training samples is necessary to guarantee higher classification performance in CNN, particularly in 3D-CNN.