• Transactions of the Korean Society of Machine Tool Engineers
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• v.13 no.2
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• pp.69-74
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• 2004

In general the surge pressure generated in hydraulic systems causes noise, vibration and odd effect to the system. To reduce the surge pressure, high frequency PWM control of 20KHz was attempted. To estimate the braking noise caused by surge, a vehicle equipped with on-board ABS hydraulic modulator has been experimented with respect to the various breaking condition. Thorough this experiments, it was found that breaking noise has been reduced using high frequency PWM control method compare with low frequency method. To evaluate high frequency control m practice, including verification of general functionality, EMI tests was experimented. Its was found that it is necessary to have the solution to electromagnetic interference(EMI) generated by switching elements.

• Progress in Superconductivity and Cryogenics
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• v.15 no.1
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• pp.51-54
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• 2013

This paper deals with harmonic components of the voltage on high temperature superconducting wire carrying an alternating current. HTS wire is used to manufacture superconducting power applications carrying an alternating current. Typically, international standard, IEC 61788-3 is used for critical current measurement. Thus, it is not ideal that critical current criteria in dc are adapted to superconducting power devices to decide the operating current of the devices. In this paper, we confirmed odd harmonic voltage on HTS wires carrying an AC. The ratio between harmonic components and fundamental component can be significant clues to decide the critical current criteria for HTS wire and its power applications in AC circumstance.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.22 no.9
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• pp.1968-1974
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• 1997

In this paper, the spectral domain approach is employed to investigate the characteristics of symmetrical and asymmetrical broadside-coupleed coplanar waveguides(BSC-CPW). These structures have large even(c)-odd(.pi.) mode-velocity ratio, suitable for wide-band and tight-coupling microwave circuit design. Efficient design parameters can be obtained from the effective dielectric constants and characteristic impedances calculated by varying the strip widths and slot widths in the BSC-CPW structure.

• Korean Journal of Clinical Laboratory Science
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• v.55 no.3
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• pp.167-173
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• 2023

This study assesses the urine microalbumin to urine creatinine ratio (uACR) with uric acid and the association with the high-density lipoprotein cholesterol (UA/HDL-C) ratio in Korean adults. Data from the 2019 Korean National Health and Nutrition Examination Survey was procured and included 5,845 adults aged 20 years or older. Several key findings were obtained in the present study. After adjusting for the related variables (age, gender, hypertension, obesity, type 2 diabetes mellitus, and chronic kidney disease), the uACR was found to be positively associated with the quartiles of the UA/HDL-C ratio (P=0.002). Moreover, after adjusting for related variables, the odds ratio (OR) of albuminuria (uACR≥30.0 mg/g) was not significant in quartile 2 (Q2) (OR, 1.015; 95% confidence interval [CI], 0.757~1.361) and Q3 (OR, 1.090; 95% CI, 0.811~1.465) but was significantly higher in Q4 (OR, 1.416; 95% CI, 1.044~1.921) as compared to Q1 of the UA/HDL-C ratio. We conclude that since the UA/HDL-C ratio is positively associated with albuminuria in Korean adults, an increased UA/HDL-C ratio could be applied as a useful measure to assess albuminuria in Korean adults.

• Journal of the Korean Society of Marine Environment & Safety
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• v.29 no.4
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• pp.356-362
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• 2023

The risk of climate change has been long acknowledged, and ongoing efforts to overcome this issue, within the shipping sector, with the international maritime organization playing a central role. Conducting research on characteristics of soot formation is crucial to control its occurrence within the combustion process. In this study, the laser extinction method and chemical reaction numerical analysis were employed to examine the alterations in the state of chemical species associated with flame temperature, flame visual, and soot formation by mixing nitrogen, an inert gas, in the counterflow diffusion flame based on ethylene gas. The findings of the study suggest that as the mixing ratio of nitrogen increased, both the flame temperature and soot volume fraction decreased. Additionally, the area in which soot particles were distributed also decreased, and the volume fraction decrease rate declined when the mixing ratio increased by more than 30%. The mole fraction of the chemical species involved in soot growth also decreased. the chemical species associated with the HACA reaction were affected by variations in the hydrocarbon fuel ratio, and the chemical species related to the odd carbon path were confirmed to be affected by the flame temperature as well as the hydrocarbon fuel ratio.

• Asian Pacific Journal of Cancer Prevention
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• v.14 no.6
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• pp.3761-3768
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• 2013

Background: The Saudi population has experienced a sharp increase in colorectal and gastric cancer incidences within the last few years. The relationship between gene polymorphisms of xenobiotic metabolizing enzymes and colorectal cancer (CRC) incidence has not previously investigated among the Saudi population. The aim of the present study was to investigate contributions of CYP1A1, CYP2E1, and GSTM1 gene polymorphisms. Materials and Methods: Blood samples were collected from CRC patients and healthy controls and genotypes were determined by polymerase chain reaction restriction fragment length polymorphism and sequencing. Results and Conclusions: $CYP2E1^*6$ was not significantly associated with CRC development (odd ratio=1.29; confidence interval 0.68-2.45). A remarkable and statistically significant association was observed among patients with $CYP1Awt/^*2A$ (odd ratio=3.65; 95% confidence interval 1.39-9.57). The $GSTM1^*0/^*0$ genotype was found in 2% of CRC patients under investigation. The levels of CYP1A1, CYP2E1 and GSTM1 mRNA gene expression were found to be 4, 4.2 and 4.8 fold, respectively, by quantitative real time PCR. The results of the present case-control study show that the studied Saudi population resembles Caucasians with respect to the considered polymorphisms. Investigation of genetic risk factors and susceptibility gene polymorphisms in our Saudi population should be helpful for better understanding of CRC etiology.

• Journal of Dental Rehabilitation and Applied Science
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• v.36 no.1
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• pp.12-20
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• 2020

Purpose: This study was designed to analyze the relationship between the presence and severity of depression and chewing problems (CPs) in a representative sample of the general population. Materials and Methods: Health surveys and examinations were conducted on a nationally representative sample (n = 8150) of Korean was conducted. CPs was determined by a simple survey response concerning "Do you feel uncomfortable about chewing your food because of problems with your mouth such as teeth, dentures and gums?" Depression was defined as individuals with a total score ≥ 10 on the Patient Health Questionnaire (PHQ)-9 survey. Data regarding demographics, socioeconomic history and comorbid health conditions were used to analyze adjusted logistic regression models. Results: In the Korean population, the prevalence of depression was significantly greater in individuals with CP (17.2%) than in those without CP (10.2%). On multivariate logistic regression analysis, the presence of depression was significantly associated with CPs (adjusted odd ratio [aOR]: 1.90, P < 0.001). The risk of CPs increased with increasing severity of depression as follows: severe depression (OR: 2.62, P < 0.001), moderately severe depression (OR: 2.19, P < 0.001). Conclusion: The presence of depression was significantly associated with CPs, especially in severely depressed individuals. Depression screening should be considered in treating CP patients.

• Asian Journal of Atmospheric Environment
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• v.9 no.4
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• pp.237-246
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• 2015

We conducted intensive observations of ozone, CO, $NO_x$ (=NO and $NO_2$), $NO_y$ (total odd nitrogen species including particulate nitrate) and total nitrate (the sum of gaseous $HNO_3$ and particulate nitrate) at Cape Hedo, Okinawa, Japan, from 19 March to 3 April, 2009, to investigate ozone production during long-range transport from the Asian continent. Ozone production efficiency (OPE) was used to evaluate photochemical ozone production. OPE is defined as the number of molecules of ozone produced photochemically during the lifetime of a $NO_x$ molecule. OPE is calculated by the ratio of the concentration increase of ozone to that of $NO_z$ ($=NO_y-NO_x$). Average OPE during observation was estimated to be $12.6{\pm}0.5$, but concentrations of ozone increased nonlinearly with those of $NO_z$. This non-linearity suggests that OPE depends on air mass origin and $NO_z$ concentrations. There were very different values of OPE for the same air mass origin, so that only the air mass origin alone does not control OPE. OPE was low when $NO_z$ concentration was high. We examined the correlation between $NO_z$ and $CO/NO_y$ ratios, which we used instead of the ratio of non-methane hydrocarbons (NMHCs) to $NO_x$. The $CO/NO_y$ ratios decreased with increasing $NO_z$ concentrations. These results indicate that competition reactions of OH with NMHCs and $NO_2$ are the rate determining steps of photochemical ozone production during long-range transport from the Asian continent to Cape Hedo, for high concentrations of nitrogen oxides.

• Asian Pacific Journal of Cancer Prevention
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• v.17 no.7
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• pp.3335-3340
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• 2016

Background: Oral submucous fibrosis (OSF) is a precancerous condition with a 4 to13% malignant transformation rate. Related to the habit of areca nut chewing it is mainly prevalent in South-east Asian countries where the habit of betel quid chewing is frequently practised. On chewing, alkaloids and polyphenols are released which undergo nitrosation and give rise to N-nitrosamines which are cytotoxic agents. CYP450 is a microsomal enzyme group which metabolizes various endogenous and exogenous chemicals including those released by areca nut chewing. CYP1A1 plays a central role in metabolic activation of these xenobiotics, whereas CYP2E1 metabolizes nitrosamines and tannins. Polymorphisms in genes that code for these enzymes may alter their expression or function and may therefore affect an individuals susceptibility regarding OSF and oral cancer. The present study was therefore undertaken to investigate the association of polymorphisms in CYP1A1 m2 and CYP2E1 (RsaI/PstI) sites with risk of OSF among areca nut chewers in the Northern India population. A total of 95 histopathologically confirmed cases of OSF with history of areca nut chewing not less than 1 year and 80, age and sex matched controls without any clinical signs and symptoms of OSF with areca nut chewing habit not less than 1 year were enrolled. DNA was extracted from peripheral blood samples and polymorphisms were analyzed by PCR-RFLP method. Gene polymorphism of CYP1A1 at NcoI site was observed to be significantly higher (p = 0.016) in cases of OSF when compared to controls. Association of CYP1A1 gene polymorphism at NcoI site and the risk of OSF (Odd's Ratio = 2.275) was also observed to be significant. However, no such association was observed for the CYP2E1 gene polymorphism (Odd's Ratio = 0.815). Our results suggest that the CYP1A1 gene polymorphism at the NcoI site confers an increased risk for OSF.

• Asian Pacific Journal of Cancer Prevention
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• v.14 no.8
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• pp.4699-4704
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• 2013

Background: MicroRNAs have been demonstrated to play important roles in the development and progression of colorectal cancer. Several studies utilizing microRNAs as diagnostic biomarkers for colorectal cancer (CRC) have been reported. The aim of this meta-analysis was to comprehensively and quantitatively summarize the diagnostic value of microRNAs for detecting colorectal cancer. Methods: We searched PubMed, Embase and Cochrane Library for published studies that used microRNAs as biomarkers for the diagnosis of colorectal cancer. Summary estimates for sensitivity, specificity and other measures of accuracy of microRNAs in the diagnosis of colorectal cancer were calculated using the bivariate random effects model. A summary receiver operating characteristic (SROC) curve was also generated to summarize the overall effectiveness of the test. Result: Thirteen studies from twelve published articles met the inclusion criteria and were included. The overall sensitivity, specificity, positive likelihood ratio, negative likelihood ratio and diagnostic odd ratio of microRNAs for the diagnosis of colorectal cancer were 0.81 (95%CI: 0.79-0.84), 0.78 (95%CI: 0.75-0.82), 4.14 (95%CI: 2.90-5.92), 0.24 (95%CI: 0.19-0.30), and 19.2 (95%CI: 11.7-31.5), respectively. The area under the SROC curve was 0.89. Conclusions: The current evidence suggests that the microRNAs test might not be used alone as a screening tool for CRC. Combining microRNAs testing with other conventional tests such as FOBT may improve the diagnostic accuracy for detecting CRC.