• Clinical and Experimental Pediatrics
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• v.51 no.3
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• pp.323-328
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• 2008

Purpose : Asthma is defined as chronic inflammation of the lower small airways, and bronchial hyperreactivity (BHR) is a pathophysiologic feature of asthma. It has been proposed that although there is no direct variable capable of assessing the small airways, a forced expiratory flow of between 25 and 75 percent ($FEF_{25-75}$) might be considered a more sensitive early marker of small airway obstruction than the forced expiratory volume in 1 second ($FEV_1$). Thus, we proposed that the presence and degree of positive responses to bronchial methacholine testing were related to the difference (DFF) and ratio (RFF) between $FEV_1$ and $FEF_{25-75}$ in asthmatic children. Methods : The subjects were 583 symptomatic children, including 324 children with BHR and 259 controls. Pulmonary function tests, methacholine challenge tests, and skin prick tests were performed, and the total eosinophil count, total serum IgE, and serum eosinophil cationic protein level were measured in all subjects. From a concentration-response curve, the methacholine concentration required to produce a decrease of 20% from post-saline $FEV_1$ was calculated ($PC_{20}$). Results : The median DFF and RFF values decreased in controls compared to subjects with bronchial hyperresponsiveness, and this trend was found in groups ranked by its severity. $PC_{20}$ had a negative correlation with DFF and RFF. Cutoff values of 0.5 for DFF and 1.042 for RFF were identified, and sensitivity and specificity were calculated. Conclusion : This study revealed that DFF and RFF might be predictive of bronchial hyperresponsiveness in the context of normal $FEV_1$ in children.

• The Journal of the Institute of Internet, Broadcasting and Communication
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• v.13 no.5
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• pp.49-54
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• 2013

We designed a burst mode optical receiver for 1.25Gbps PON(Passive Optical Network), fabricated it using $0.8{\mu}m$ BiCMOS foundry. We minimized the loss of the data in the front of the burst by reducing AGC(Automatic Gain Control) signal generation time using an exponential amplifier. We confirmed that AGC of the burst mode optical receiver functioned well and showed good performance in measurement. However, although the eye of the eye pattern was opened the jitter characteristic was deteriorated due to the heavy waveform distortion.

• Korean Journal of Clinical Laboratory Science
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• v.55 no.4
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• pp.291-297
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• 2023

Gastritis is an inflammation of the gastric mucosa and gastric ulcers are a break in the mucosa of the stomach lining. Past research on gastritis and gastric ulcers has been mainly conducted from the perspective that environmental factors are the primary cause of these gastric diseases. However, recently the importance of genetic factors has been emphasized due to current developments in genetic research. The SLC25A26 gene is believed to be associated with the accumulation of reactive oxygen species. Oxidative stress promotes an inflammatory response, which increases the production of free radicals and causes cellular damage, and these lead to the development of gastric diseases. In this study, the correlation between SLC25A26 and gastric diseases was analyzed. Polymorphisms in SLC25A26 were analyzed in 1,369 domestic gastric disease patients and 7,471 healthy controls. As a result, 11 single nucleotide polymorphisms (SNPs) (in the genotype) and 13 SNPs (in the imputation) showed statistical significance (P<0.05), and high relative risk of gastric diseases. Among them, the rs13874 allele of SLC25A26 showed a highly significant association with gastric diseases. In the genotype-based mRNA expression analysis, the minor allele (C) group showed increased mRNA expression and this could increase oxidative stress. In conclusion, SLC25A26 polymorphisms are associated with gastric diseases. These results may provide a basis for new guidelines for gastric disease management in the Korean population.

• Journal of the Semiconductor & Display Technology
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• v.18 no.1
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• pp.21-24
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• 2019

In this paper, 5.8GHz 25W microwave wireless power transmission system was developed. The transmission system is composed of a signal generator, a 1W drive amplifier, a 25W power amplifier, and a circularly polarized transmission antenna. The receiving system was fabricated with an integrated receiver that combines a circularly polarized receiving antenna, a pass band filter, and an RF-DC converter. And a multi-integrated receiver had twelve parts, including an integrated receiver. Under the conditions, voltage and current were measured for the system at 5cm intervals from a minimum distance of 5cm to a maximum distance of 80cm. The power was calculated for the system. The results of the system are shown in tables and graphs. The power decreases with distance, but the power does not drop sharply due to a multi-integrated receiver.

• Asian Pacific Journal of Cancer Prevention
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• v.16 no.6
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• pp.2227-2230
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• 2015

Background: Prostate cancer (PCa) is one of the most commonly diagnosed neoplasms and the second leading cause of cancer death in men in the Western world. Vitamin D (1,25dihydroxy vitamin D) is linked to many biological processes that influence oncogenesis but data on relations between its genetic variants and cancer risk have been inconsistent. The aim of this study was to determine associations between a vitamin D genetic polymorphism and 25-hydroxyvitamin D [25(OH)D] levels and prostate cancer. Materials and Methods: Genomic DNA was extracted from 124 Jordanian prostate cancer patients and 100 healthy volunteers. Ethical approval was granted from the ethical committee at Hashemite University and written consent was given by all patients. PCR was used to amplify the vitamin D receptor Fok1 polymorphism fragment. 25(OH)D serum levels were measured by competitive immunoassay. Results: All genotypes were in Hardy-Weinberg equilibrium. Genotype frequency for Fok1 genotypes FF, Ff and ff was 30.7%, 61.3% and 8.06%, for prostate cancer patients, while frequencies for the control group was 28.0%, 66.0% and 6.0%, respectively, with no significant differences. Vitamin D serum level was significantly lower in prostate cancer patients (mean 7.7 ng/ml) compared to the control group (21.8 ng/ml). No significant association was noted between 25(OH)D and VDR Fok1 gene polymorphism among Jordanians overall, but significant associations were evident among prostate cancer patients (FF, Ff and ff : 25(OH)D levels of 6.2, 8.2 and 9.9) and controls (19.0, 22.5 and 26.3, respectively). An inverse association was noted between 25(OH)D serum level less than 10ng/ml and prostate cancer risk (OR 35.5 and 95% CI 14.3- 88.0). Conclusions: There is strong inverse association between 25(OH)D serum level less than 10ng/ml level and prostate cancer risk.

• Journal of Nutrition and Health
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• v.56 no.1
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• pp.1-11
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• 2023

Purpose: Obesity is associated with alterations in vitamin D metabolism and elevation of parathyroid hormone (PTH). Increased PTH level in obesity is likely one of the factors contributing to the dysregulation of vitamin D metabolism. We investigated the effects of lowering the PTH level in high-fat diet-induced obese mice on vitamin D metabolism. Methods: Five-week-old male C57BL/6N mice were fed either with control (10% energy as fat) or high-fat (60% energy as fat) diets ad libitum for 12 weeks, and vehicle or cinacalcet HCl (30 ㎍/g body weight) was gavaged daily during the final week of the experiment. The following groups were studied: CON (control diet + vehicle), HFD (high-fat diet + vehicle), and HFD-CIN (high-fat diet + cinacalcet HCl). PTH, 1,25-dihydroxyvitamin D (1,25[OH]₂D), 25-hydroxyvitamin D (25[OH]D), calcium, and phosphate levels in circulation, and the expression of genes related to vitamin D metabolism in the liver and kidneys were determined. Results: Renal 1α-hydroxylase expression in the HFD group was higher than that in the CON group despite the lack of a difference in the PTH levels between the 2 groups. The plasma PTH level in the HFD-CIN group was 60% lower than that in the HFD group (p < 0.05). In parallel, the HFD-CIN group had lower adipose tissue amount (9% lower), renal 1α-hydroxylase expression (48% lower), and plasma 1,25(OH)₂D concentration (38% lower) than the HFD group. Conclusion: Lowering the PTH levels in high-fat diet-induced obese mice recovered the expression of renal 1α-hydroxylase and might be associated with lower amounts of white adipose tissue.

• Transactions of the Korean Society of Mechanical Engineers
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• v.18 no.11
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• pp.2860-2870
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• 1994

When crack are detected in aged turbine rotors of power plants, information on fracture resistance of the aged material at operating temperature is needed for determination of critical loading condition and residual life of the turbine. In this study, fracture toughness (J$_lc$) and tearing modulus(T$_mat$) of virgin and thermally degraded 1Cr-1Mo-0.25V steel, which is one of the most widely used rotor steels, were measured at 538.deg. C according to ASTM E813 and ASTM E1152, respectively. Five kinds of specimen with different degradation levels were prepared by isothermal aging heat treatment at $630^{\circ}C.$ It was observed that J$_lc$ and T$_mat$ value decreased as the degradation level increased. Analysis of microstructures using a scanning electron microscope showed that the decrement of J$_lc$ is related to segregation of impurities at grain boundaries. It was also verified that the DC electric potential drop method is accurate and reliable for crack length monitoring at elevated temperature.

• Journal of Ginseng Research
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• v.39 no.2
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• pp.148-154
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• 2015

Background: Ginseng is known to have antiapoptotic, anti-inflammatory, and antioxidant effects. The present study investigated a possible role of Korean Red Ginseng (KRG) in suppressing dopaminergic neuronal cell death and the cleavage of p35 to p25 in the substantia nigra (SN) and striatum (ST) using a 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP)-induced Parkinson's disease mouse model. Methods: Ten-week-old male C57BL/6 mice were injected intraperitoneally with 30 mg/kg of MPTP at 24-h intervals for 5 d, and then administered KRG (1 mg/kg, 10 mg/kg, or 100 mg/kg) once a day for 12 consecutive days from the first injection. Pole tests were performed to assess the motor function of the mice, dopaminergic neuronal survival in the SN and ST was evaluated using tyrosine hydroxylase-immunohistochemistry, and the expressions of cyclin-dependent kinase 5 (Cdk5), p35, and p25 in the SN and ST were measured using Western blotting. Results: MPTP administration caused behavioral impairment, dopaminergic neuronal death, increased Cdk5 and p25 expression, and decreased p35 expression in the nigrostriatal system of mice, whereas KRG dose-dependently alleviated these MPTP-induced changes. Conclusion: These results indicate that KRG can inhibit MPTP-induced dopaminergic neuronal death and suppress the cleavage of p35 to p25 in the SN and the ST, suggesting a possible role for KRG in the treatment of Parkinson's disease.

• Communications of the Korean Mathematical Society
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• v.25 no.1
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• pp.19-25
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• 2010

$3{\times}3{\times}3$ is the meaningful smallest product of three chains of each size 2n+1 since $1{\times}1{\times}1$ is a 1-element poset. The linear discrepancy of the product of three chains $2n{\times}2n{\times}2n$ is found as $6n^3-2n^2-1$. But the case of the product of three chains $(2n + 1){\times}(2n + 1){\times}(2n + 1)$ is not known yet. In this paper, we determine ld$(3{\times}3{\times}3)$ as a case to determine the linear discrepancy of the product of three chains of each size 2n + 1.

• Asian Pacific Journal of Cancer Prevention
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• v.16 no.6
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• pp.2507-2513
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• 2015

Background: Serum vitamin D status can affect the prognosis of breast cancer patients. Our aim was to determine the association between alterations in the 25-hydroxyvitamin D [25(OH)D] status during follow-up and the prognosis of breast cancer patients. Additionally, we evaluated the association between the 25(OH)D status at the time of diagnosis and the prognosis using a detailed age and stage categorization. Materials and Methods: Four hundred and sixty-nine Korean breast cancer patients were included. We collected patient clinicopathological data, including their serum 25(OH)D concentration at diagnosis and at the annual follow-up until 4 years after diagnosis. The patients were divided according to their 25(OH)D status at diagnosis into a deficient (<20 ng/ml) and a non-deficient (${\geq}20ng/ml$) group. At follow-up, patients were categorized into the four following groups according to 25(OH)D status alterations: persistently deficient, improved, deteriorated and persistently non-deficient. Results: At diagnosis, 118 patients were classified into the deficient group and 351 into the non-deficient group. After a median follow-up period of $85.8{\pm}31.0$ months, the patients with advanced-stage disease or an older age in the non-deficient group showed a significantly better survival compared with the deficient group. Furthermore, at the 1-year follow-up of 25(OH)D status, the persistently non-deficient group and the improved group had better survival compared with the other two groups. Conclusions: Our results suggest that maintaining an optimal 25(OH)D status at diagnosis and during the 1-year follow-up period is important for improving breast cancer patient survival.