• Journal of the korean academy of Pediatric Dentistry
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• v.29 no.4
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• pp.600-606
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• 2002

The purpose of this study was to evaluate the diagnostic validity of an incipient occlusal caries using argon laser fluorescence. Extracted human premolars and molars with enamel carious lesion of occlusal surface were assessed using visual examination, visual examination with probing, argon laser fluorescence and histologic depth of carious lesion. The results in each of all the three detection methods were compared to the assessment of histologic depth of carious lesion using polarized microscope. The results from the present study can be summarized as follows; 1. There was highly correlation between the histologic depth of occlusal caries and all three detection methods(P<0.01). 2. The reproducibility(kappa value) of the visual examination, visual examination with probing and argon laser fluorescence between the histologic depth of occlusal caries was 0.189, 0.128, 0.472. The highest correlation was seen between detection of occlusal caries by argon laser fluorescence and histologic scores by polarized microscope. The results from this study indicated that argon laser fluorescence considered to be accurate and reliable method in detecting occlusal caries.

• Journal of Preventive Medicine and Public Health
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• v.42 no.2
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• pp.117-122
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• 2009

Objectives : We tried to evaluate the agreement of the Charlson comorbidity index values(CCI) obtained from different sources(medical records and National Health Insurance claims data) for gastric cancer patients. We also attempted to assess the prognostic value of these data for predicting 1-year mortality and length of the hospital stay(length of stay). Methods : Medical records of 284 gastric cancer patients were reviewed, and their National Health Insurance claims data and death certificates were also investigated. To evaluate agreement, the kappa coefficient was tested. Multiple logistic regression analysis and multiple linear regression analysis were performed to evaluate and compare the prognostic power for predicting 1 year mortality and length of stay. Results : The CCI values for each comorbid condition obtained from 2 different data sources appeared to poorly agree(kappa: 0.00-0.59). It was appeared that the CCI values based on both sources were not valid prognostic indicators of 1-year mortality. Only medical record-based CCI was a valid prognostic indicator of length of stay, even after adjustment of covariables($\beta$ = 0.112, 95% CI = [0.017-1.267]). Conclusions : There was a discrepancy between the data sources with regard to the value of CCI both for the prognostic power and its direction. Therefore, assuming that medical records are the gold standard for the source for CCI measurement, claims data is not an appropriate source for determining the CCI, at least for gastric cancer.

• Journal of radiological science and technology
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• v.39 no.3
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• pp.329-336
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• 2016

The purpose of this study was to evaluate the usefulness of low-dose CT (LDCT) for emphysema compared with high-resolution CT (HRCT). Measurements of radiation dose and noise were repeated 3 times in same exposure condition which was similar with obtaining HRCT and LDCT images. We analysed reading results of 146 subjects. Six images per participants selected for emphysema grading. Emphysema was graded for all 6 zones on the left and right sides of the lungs by the consensus reading of two chest radiologists using a 4-point scale. Between the HRCT and LDCT images, diagnostic differences and agreements for emphysema were analyzed by McNemar's and unweighted kappa tests, and radiation doses and noise by a Mann-Whitney U-test, using the SPSS 19.0 program. Radiation dose from HRCT was significantly higher than that of LDCT, but the noise was significantly lower in HRCT than in LDCT. Diagnostic agreement for emphysema between HRCT and LDCT images was excellent (k-value=0.88). Emphysema grading scores were not significantly different between HRCT and LDCT images for all six lung zones. Emphysema grading scores from LDCT images were significantly correlated with increased scores on HRCT images (r=0.599, p < 0.001). Considering the tradeoff between radiation dose and image noise, LDCT could be used as the gold standard method instead of HRCT for emphysema detection and grading.

• Korean Journal of Agricultural Science
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• v.36 no.1
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• pp.111-122
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• 2009

When the cattail pollen was identified by using fibrinolytic agents, we found that the fibrinolytic activity was controlled by an enzyme. Therefore, for determining the fibrinolytic activity of cattail pollen, the fibrinolytic enzyme in cattail pollen was purified by gel filtration using DEAE-cellulose, Sephadex G-150 and HPLC. Also, its purity was certified by polyacrylamide gel electrophoresis, and its physico-chemical properties, such as pH and temperature stabilities and effects of metal, inhibitors and substrates, were examined. The specific activity, purification fold, and molecular weight of the enzyme were 38U/mg, 86.4,and 75kDa, respectively. The optimum pH for the purified enzyme was at 4.0 and it was stable at pH 4.0-6.0. The optimum temperature was $55^{\circ}C$ and it was stable at $30-60^{\circ}C$. But the enzyme began to be inactivated at $70^{\circ}C$ and its activity was totally lost at temperatures above $80^{\circ}C$. As for substrate specificity, the enzyme was most effective in dissolving fibrin, followed by whole casein, ${\kappa}$-casein, ${\alpha}$-casein, ${\beta}$-casein, and BSA. With casein as the substrate, Km value was found to be 0.44mM and the enzyme showed a high affinity for casein. As for the metal ions affecting enzyme activity, $K^+$, $Na^+$, and $Mg^{2+}$ had no effect on enzyme reaction while $Zn^{2+}$ and $Fe^{2+}$ showed potent inhibitory activity. Judging from the fact that the purified enzyme was also strongly inhibited by PMSF, iodoacetic acid, and SDA, it assumed to be a serine protease.

• Journal of the Korean Society of Surveying, Geodesy, Photogrammetry and Cartography
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• v.38 no.3
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• pp.187-196
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• 2020

In this study, collapsed building detection using UAV (Unmanned Aerial Vehicle) and PlanetScope satellite images was carried out, suggesting the possibility of utilization of heterogeneous sensors in object detection located on the surface. To this end, the area where about 20 buildings collapsed due to forest fire damage was selected as study site. First of all, the feature information of objects such as ExG (Excess Green), GLCM (Gray-Level Co-Occurrence Matrix), and DSM (Digital Surface Model) were generated using high-resolution UAV images performed object-based segmentation to detect collapsed buildings. The features were then used to detect candidates for collapsed buildings. In this process, a result of the change detection using PlanetScope were used together to improve detection accuracy. More specifically, the changed pixels acquired by the bitemporal PlanetScope images were used as seed pixels to correct the misdetected and overdetected areas in the candidate group of collapsed buildings. The accuracy of the detection results of collapse buildings using only UAV image and the accuracy of collapse building detection result when UAV and PlanetScope images were used together were analyzed through the manually dizitized reference image. As a result, the results using only UAV image had 0.4867 F1-score, and the results using UAV and PlanetScope images together showed that the value improved to 0.8064 F1-score. Moreover, the Kappa coefficiant value was also dramatically improved from 0.3674 to 0.8225.

• Journal of Korean Society of Forest Science
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• v.110 no.4
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• pp.610-621
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• 2021

The soil creep, primarily caused by earthquakes and torrential rainfall events, has widely occurred across the country. The Korea Forest Service attempted to quantify the soil creep susceptible areas using a discriminant value table to prevent or mitigate casualties and/or property damages in advance. With the advent of advanced computer technologies, machine learning-based classification models have been employed for managing mountainous disasters, such as landslides and debris flows. This study aims to quantify the soil creep susceptibility using several classifiers, namely the k-Nearest Neighbor (k-NN), Naive Bayes (NB), Random Forest (RF), and Support Vector Machine (SVM) models. To develop the classification models, we downscaled 292 data from 4,618 field survey data. About 70% of the selected data were used for training, with the remaining 30% used for model testing. The developed models have the classification accuracy of 0.727 for k-NN, 0.750 for NB, 0.807 for RF, and 0.750 for SVM against test datasets representing 30% of the total data. Furthermore, we estimated Cohen's Kappa index as 0.534, 0.580, 0.673, and 0.585, with AUC values of 0.872, 0.912, 0.943, and 0.834, respectively. The machine learning-based classifications for soil creep susceptibility were RF, NB, SVM, and k-NN in that order. Our findings indicate that the machine learning classifiers can provide valuable information in establishing and implementing natural disaster management plans in mountainous areas.

• Korean Journal of Clinical Laboratory Science
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• v.51 no.2
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• pp.171-176
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• 2019

A comparative study between commercially available mycobacteria growth indicator tubes (MGIT) in the BACTEC MGIT 960 System and the conventional Ogawa media was carried out to assess the effectiveness of the re-decontaminating process for the recovery of mycobacteria. Processed specimens with 5% sodium hydroxide and 0.5% N-acetyl-L-cysteine were inoculated into MGIT and Ogawa media. The acid fast bacilli (AFB) recovered from the cultures were identified using a mycobacterium tuberculosis (TB) antigen kit. If contaminants were observed in the MGIT tubes within five days, a decontaminating process was repeated. A total of 1,190 out of 4,790 (24.8%) specimens showed positive results using the BACTEC MGIT 960 system. Among them, 278 specimens were reprocessed. When the MGIT and Ogawa results were compared, it showed discordant results (weighted kappa value: 0.283). One TB and 10 nontuberculous mycobacteria (NTM) were newly detected in MGIT only. The likely benefit of the re-decontaminating process is the detection of additional mycobacteria that could not be detected without a re-decontaminating process despite being small in number. In addition to the combination of MGIT and Ogawa, the re-decontaminating process is recommended in the case of contaminations to recover mycobacteria.

• Journal of Korean Neurosurgical Society
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• v.52 no.3
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• pp.200-203
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• 2012

Objective : The sub-axial injury classification (SLIC) and severity scale was developed to decide whether to operate the cervical injured patient or not, but the reliability of SLIC and severity scale among the different physicians was not well known. Therefore, we evaluated the reliability of SLIC among a spine surgeon, a resident of neurosurgery and a neuro-radiologist. Methods : In retrograde review in single hospital from 2002 to 2009 years, 75 cases of sub-axial spine injured patients underwent operation. Each case was blindly reviewed for the SLIC and severity scale by 3 different observers by two times with 4 weeks interval with randomly allocated. The compared axis was the injury morphology score, the disco-ligamentous complex score, the neurological status score and total SLIC score; the neurological status score was derived from the review of medical record. The kappa value was used for the statistical analysis. Results : Interobserver agreement of SLIC and severity scale was substantial agreement in the score of injury morphology [intraclass correlation (ICC)=0.603] and total SLIC and severity sacle (ICC value=0.775), but was fair agreement in the disco-ligamentous complex score (ICC value= 0.304). Intraobserver agreements were almost perfect agreement in whole scales with ICC of 0.974 in a spine surgeon, 0.948 in a resident of neurosurgery, and 0.963 in a neuro-radiologist. Conclusion : The SLIC and severity scale is comprehensive and easily applicable tool in spine injured patient. Moreover, it is very useful tool to communicate among spine surgeons, residents of neurosurgery and neuro-radiologists with sufficient reproducibility.

• Asian Pacific Journal of Cancer Prevention
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• v.17 no.7
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• pp.3489-3494
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• 2016

Background: A major problem with cervical cancer screening in countries which have no organized national screening program for cervical cancer is sub-optimal participation. Implementation of self-sampling method may increase the coverage. Objective: We determined the agreement of cytological diagnoses made on samples collected by women themselves (self-sampling) versus samples collected by physicians (Physician sampling). Materials and Methods: We invited women volunteers to undergo two procedures; cervical self-sampling using the Evalyn brush and physician sampling using a Cervex brush. The women were shown a video presentation on how to take their own cervical samples before the procedure. The samples taken by physicians were taken as per routine testing (Gold Standard). All samples were subjected to Thin Prep monolayer smears. The diagnoses made were according to the Bethesda classification. The results from these two sampling methods were analysed and compared. Results: A total of 367 women were recruited into the study, ranging from 22 to 65 years age. There was a significant good agreement of the cytological diagnoses made on the samples from the two sampling methods with the Kappa value of 0.568 (p=0.040). Using the cytological smears taken by physicians as the gold standard, the sensitivity of self-sampling was 71.9% (95% CI:70.9-72.8), the specificity was 86.6% (95% CI:85.7-87.5), the positive predictive value was 74.2% (95% CI:73.3-75.1) and the negative predictive value was 85.1% (95% CI: 84.2-86.0). Self-sampling smears (22.9%) allowed detection of micro-organisms better than physicians samples (18.5%). Conclusions: This study shows that samples taken by women themselves (self-sampling) and physicians have good diagnostic agreement. Self-sampling could be the method of choice in countries in which the coverage of women attending clinics for screening for cervical cancer is poor.

• Asian Pacific Journal of Cancer Prevention
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• v.13 no.8
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• pp.3611-3615
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• 2012

Objective: The objective of this study was to establish the diagnostic accuracy, specificity and sensitivity of fine needle aspiration cytology(FNAC) for intra-oral tumors, comparing with histopathology as the gold standard. Materials and methods: Forty cases of FNA cytology from intraoral tumors was performed in AFID along with the demographic data and clinical information and then diagnosed at AFIP, Rawalpindi. Then the cytology results obtained per FNAC were compared with the histopathological biopsy results of the same lesions. The following variables were recorded for each patient: Age, gender, site of biopsy, diagnosis. The data were entered and analyzed using Open-epi version 2.0. Diagnostic accuracy, sensitivity, specificity, positive predictive value and negative predictive value were calculated. Cohen Kappa was further applied to compare the agreement between the biopsy and FNAC diagnoses. A p-value of < 0.05 was considered as statistically significant. Results: Among the total patients included in the study there were 24 males and 16 females, with a ratio of 1.5:1. Age of the patients ranged from 24 to 80 years with a mean of 52 years. A total of six sites were aspirated from the oral cavity with maximum (11) aspirates taken from alveolar ridge. The results of FNAC revealed that there were 32 malignant and 8 benign aspirates. Confirmation through histopathological analysis came for 31/32 malignant cases while one was falsely given positive for malignancy on FNAC. Among a total of 40 cases, 31(77%) cases diagnosed were found to be malignant and remaining 9(23%) were benign. The FNAC results revealed 32 malignant and 8 benign lesions. Histopathology of the subsequent surgically excised specimen showed malignant lesions in 31(77%) and benign in 9(23%) patients. As a whole, it was found that the absolute sensitivity for introral FNAC was 100% and specificity 89% with positive predictive value of 97% and negative predictive value of 100%. Conclusion: Cytological diagnosis was almost corroborative with final histopathological diagnosis in all cases, with very few exceptions, exhibiting high diagnostic accuracy.