• Transactions of the Korean Society of Automotive Engineers
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• v.10 no.3
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• pp.61-69
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• 2002

To meet stringent LEV and ULEV emission standards, a considerable amount of development work was necessary to ensure suitable efficiency and durability of catalyst systems. The main challenge is to cut off the engine cold-start emissions. It is known that up to 80% of the total hydrocarbons(THC) are exhausted within the first five minutes in case of US FTP 75 cycle. Close-Coupled Catalyst(CCC) provides fast light-off temperature by utilizing the energy in the exhaust gas. However, if some malfunction occurred at engine operation and the catalyst temperature exceeds 1050$\^{C}$, the catalytic converter is deactivated and shows the poor conversion efficiency. This paper presents effEcts of engine operating conditions on catalytic converter temperature in a SI engine, which are the indications of catalytic deactivation. Exhaust gas temperature and catalyst temperature were measured as a function of air/fuel ratio, ignition timing and misfire rates. Additionally, light-off time was measured to investigate the effect of operating conditions. It was found that ignition retard and misfire can result in the deactivation of the catalytic converter, which eventually leads the drastic thermal aging of the converter. Significant reduction in light-off time can be achieved with proper control of ignition retard and misfire, which can reduce cold-start HC emissions as well.

• Clinical and Experimental Reproductive Medicine
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• v.37 no.2
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• pp.115-124
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• 2010

Objective: To testify whether the increased peripheral blood natural killer (pbNK) cells fraction and their cytolytic activity could coincide with patient's history of recurrent spontaneous abortion (RSA) and to evaluate these factors are can be valuable diagnostic markers in RSA. Methods: Women with a history of RSA comprised the patient group (n=35). Normal fertile women, who were experienced at least one healthy term birth without history of infertility or recurrent miscarriage, were included as the healthy control group (n=15). The pbNK cells of $CD3^-/CD56^+/CD16^+$ and their cytolytic activities against K562 cells were measured by flow cytometry and the values were compared between study and control groups. Results: Proportions of pbNK cells among peripheral blood monocytes (PBMC) ($14.2{\pm}5.2$ vs. $9.4{\pm}3.7%$, p=0.002, 95% confidence interval [CI], 1.8 to 7.8) was significantly higher in the patient group. The odds ratio of having RSA history was increased as 8.4 folds (59% of sensitivity, 80% of specificity, and 95% CI: 2.0 to 35.8) in patients who showed pbNK cells fraction above 12.1% which was determined as cut-off value by using ROC curve analysis. The cytolytic activities of pbNK cells which measured by three different ratio of effecter pbNK cells to target K562 cells and calculated by the percent of cytolytic K562 cells, were significantly higher in study group than that of control group (in 50:1 ratio, $48.3{\pm}19.0$ vs. $31.3{\pm}11.9%$, p=0.002; in 25:1 ratio, $37.0{\pm}18.1$ vs. $20.2{\pm}9.2%$, p<0.001; in 12.5:1 ratio, $23.5{\pm}12.7$ vs. $12.4{\pm}7.3%$, p=0.001). With the cut-off values of cytolytic activity of pbNK cells as 43.1% (50:1), 26.9% (25:1), and 17.4% (12.5:1) each, the risk of having RSA history was increased by 10.0, 11.4, and 15.0 folds in patients who had increased in each effector of pbNK to target of K562 cells ratio. Conclusion: The analysis of pbNK cells fraction and their cytolytic activity can be valuable diagnostic markers for RSA. We are going to planning the large scaled studies which include the data of obstetric outcomes in subsequent pregnancies to clarify our results of this study.

• Asian Pacific Journal of Cancer Prevention
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• v.15 no.6
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• pp.2647-2650
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• 2014

Background: Colorectal cancers(CRC) are the third most common cancer in the western world, with surgery preferred for management of non-metastatic disease and post surgical treatment usually arranged according to the TNM staging system. However, there is still prognostic variation between patients who have the same stage. It is increasingly recognized that variations within disease course and clinical outcome in colorectal cancer patients are influenced by not only oncological characteristics of the tumor itself but also host response factors. Recent studies have shown correlation between the inflammatory response and clinical outcomes in various cancers. The neutrophil/lymphocyte ratio (NLR) has been described as a marker for immune response to various stimuli including cancer. Material-Methods: Two hundred eighty-one CRC patients were included in our retrospective analysis, separated into two groups according to a cut-off value for the NLR. Patient data including age, gender, vertical penetration, anatomic location, and differentiation of the tumor, TNM stage, survival rate, and disease-free survival were analyzed for correlations with the NLR. Results: Using ROC curve analysis, we determined a cut-off value of 2.2 for NLR to be best to discriminate between patient survival in the whole group. In univariate analysis, high pretreatment NLR (p=0.001, 95%CI 1.483-4.846), pathologic nodal stage (p<0.001, 95%CI 1.082-3.289) and advanced pathologic TNM stage (p<0.001, 95%CI 1.462-4.213) were predictive of shorter survival. In multivariate analysis, advanced pathologic TNM stage (p=0.001, 95%CI 1.303-26.542) and high pretreatment NLR (p=0.005, 95%CI 1.713-6.378) remained independently associated with poor survival. Conclusions: High pre-treatment NLR is a significant independent predictor of shorter survival in patients with colorectal cancer. This parameter is a simple, easily accessible laboratory value for identifying patients with poorer prognosis.

• Journal of radiological science and technology
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• v.44 no.4
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• pp.307-313
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• 2021

The purpose of this study was to analyze the risk factors for uterine myoma diagnosed by ultrasonography in Korea women and to evaluate the risk. Among the patients who visited the outpatient department of obstetrics and gynecology at I hospital in Busin between January 2019 and March 2021 for the purpose of examination, 98 patients in the experimental group diagnosed with uterine myoma and 163 patients in the normal control group without other diseases were retrospectively conducted. Among the general characteristics of the subjects, age, body mass index, parity, and menopause showed significant differences between the myoma group and the normal control group. ROC(receiver operating characteristic) curve analysis and logistic regression analysis were performed to obtain the cut off value and odds ratio that can predict the occurrence of uterine myoma. The cut off value for the prediction of uterine myoma was determined to be 30 years old and a body mass index of 23 kg/m². After that adjusting for menopause, non menopausal cases with a body mass index of 23 kg/m² and over 39 years of age had the highest odds ratio of 6.04. Therefore, premenopausal women over 40 years of age require regular checkups and thorough weight management. This study was conducted with a small number of subjects. Therefore, there is a limit to generalizing to all Korean women. However, based on this study if a large scale prospective study considering various variables is made, it can play a role as a predictive marker in early detection of uterine myoma.

• The Transactions of the Korean Institute of Electrical Engineers C
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• v.48 no.5
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• pp.315-318
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• 1999

We have proposed and fabricated the new bottom-gated polycrystalline silicon (poly-Si) thin film transistor (TFT) with a partial amorphous-Si region by employing the selective laser annealing. The channel layer of the proposed TFTs is composed of poly-Si region in the center and a-Si region in the edge. The TEM image shows that the local a-Si region is successfully fabricated by the effective cut out of the incident laser light in the upper a-Si layer. Our experimental results show that the ON/OFF current ratio is increased significantly by more than three orders in the new poly-Si TFT compared with conventional poly-Si TFT. The leakage current is decreased significantly due to the highly resistive a-Si re TFTs while the ON-series resistance of the local a-Si is reduced significantly due to the considerable inducement of electron carriers by the positive gate bias, so that the ON-current is not decreased much.

• Asian Pacific Journal of Cancer Prevention
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• v.13 no.11
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• pp.5695-5699
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• 2012

We investigated the relationships between demographics, lifestyle characteristics, and serum total prostate specific antigen (PSA) concentration and examined the population-based distribution of total PSA by age among 2,246 Korean men with a median age of 45 years. We obtained data about demographic and lifestyle characteristics based on self-reporting using a quetionnaire. We also performed physical examinations, anthropometric measurements, and biochemical measurements. The PSA concentration increased with age and there was a significant difference in total PSA concentration between the age groups of 21-60 years and >60 years. Age >60 years, height ${\geq}1.8$ m, a low frequency of alcohol consumption, and taking nutritional supplements showed a significantly increased odds ratio for increased PSA when 3.0 ng/mL was chosen as the PSA cut-off level. Smoking status, BMI, percent body fat, diabetes mellitus, fatty liver, herbal medicine use, vitamin use, and diet were not significantly associated with total PSA regardless of the cut-off level. When interpreting a single PSA test, height, alcohol consumption, and nutritional supplement use should be considered, in addition to age.

• Journal of Korean Academy of Nursing
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• v.41 no.6
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• pp.758-767
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• 2011

Purpose: This study was done to examine the threshold value of estimated height loss at which the risk of osteoporosis increases and to verify its discriminative ability in the detection of osteoporosis. Methods: It was conducted based on epidemiological descriptive methods on 732 Korean women at a public healthcare center in Seoul between July and November 2010. ANOVA, Pearson correlation, logistic regression analysis and receiver operating characteristics (ROC) curve were used for data analysis. Results: There was an age-related correlation between bone mineral density (lumbar spine: F=37.88, p<.001; femur: F=54.27, p<.001) and estimated height loss (F=27.68, p<.001). Estimated height loss increased significantly with decreasing bone mineral density (lumbar spine: r=-.23, p<.001; femur: r=-.34, p<.001). The odds ratio for the point at which the estimated height loss affects the occurrence of osteoporosis was found to increase at a cut-off value of 2 cm and the area under ROC curve was .71 and .82 in lumbar spine and femur, respectively. Conclusion: The optimal cut-off value of the estimated height loss for detection of osteoporosis was 2 cm. Height loss is therefore a useful indicator for the self-assessment and prognosis of osteoporosis.

• Toxicological Research
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• v.18 no.3
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• pp.227-232
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• 2002

In order to find out the appropriate in vitro method for high correlation with in vivo, we com-pared the sensitivities of phototoxicity (PT) in vitro method between in human keratinocytes, HaCaT cells and in 3T3 fibroblast cells derived from Balb/c mice. Both cells were exposed to six known phototoxic chemicals : promethazine, neutral red, chlortetracycline, amiodarone, bithionol, 8-methoxypsoralen, or non-phototoxic chemical, ALS (ammonium laureth sulfate) and then irradiated with 5 J/$cm^2$ of UVA. Cell viability ($IC_{50}$ ) was measured by neutral red uptake (NRU) assay. The ratio of $IC_{50}$ value of chemicals in the presence and absence of UVA was determined by the cut-off value. The phototoxic potential of test chemicals in NRU assay was determined by measuring the photoirriation factor (PIF) with a cut-off value of 5. In both 3T3 and HaCaT cells, all known phototoxic chemicals were positive (over 5 of PIF value), except that bithionol was found to be non-phototoxic to HaCaT cells, and ALS, non-phototoxic chemical was negative. These results suggest that Balb/c 3T3 cell was more sensitive than HaCaT cell to predict phototoxicity potential.

• Nuclear Engineering and Technology
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• v.6 no.2
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• pp.89-96
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• 1974

The cross-section ratios of the nuclear isomeric pairs $^{80}$ B $r^{m, g}$, sup 81/S $e^{m, g}$, $^{104}$ R $h^{m, g}$, $^{116}$ I $n^{m, g}$ and $^{134}$ C $s^{m, g}$ through the radiative thermal neutron capture process have been studied. The experimental values of these ratios obtained by the activation method have been compared with the calculated ones deduced from the modified Huizenga-Vandenbosch method. Agreement between these values within 30% could be attained by controlling the spin cut-off parameter and gamma-ray multiplicity.

• Journal of the Korean Academy of Child and Adolescent Psychiatry
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• v.30 no.1
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• pp.9-16
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• 2019

Objectives: The purpose of this study was to analyze the discriminant validity and the clinical cut off scores of the Child Behavior Checklist 1.5-5 (CBCL 1.5-5) in the diagnosis of autism spectrum disorder (ASD) and non-ASD. Methods: In total, 104 ASD and 441 non-ASD infants were included in the study. T-test, discriminant analysis, receiver operating characteristic (ROC) curve analysis, and odds ratio analysis were performed on the data. Results: The discriminant validity was confirmed by mean differences and discriminant analysis on the subscales of Emotionally reactive, Somatic complaints, Withdrawn, Sleep problems, Attention problems, Aggressive behavior, Internalizing problems, Externalizing problems, and Total problems, along with the Diagnostic and Statistical Manual of Mental Disorders (DSM)-oriented scales between the two groups. ROC analysis showed that the following subscales significantly separated ASD from normal infants: Emotionally reactive, Somatic complaints, Withdrawn, Sleep problems, Attention problems, Aggressive behavior, Internalizing problems, Externalizing problems, Total problems, and DSM pervasive developmental problems. Moreover, the clinical cut off score criteria adopted in the Korean-CBCL 1.5-5 were shown to be valid for the subscales Withdrawn, Internalizing problems, Externalizing problems, Total problems, and DSM pervasive developmental problems. Conclusion: The subscales of Withdrawn, Internalizing problems, Externalizing problems, Total problems, and DSM pervasive developmental problems significantly discriminated infants with ASD.