• Korean Journal of Clinical Pharmacy
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• v.17 no.1
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• pp.13-18
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• 2007

The purpose of the present study was to investigate the effect of cimetidine on theophylline pharmacokinetics in Korean healthy normal subjects. Eight subjects were enrolled and open label, two period cross-over study was conducted without significant drug related adverse reactions. Cimetidine seemed that significantly inhibited the metabolism of theophylline, oral clearance decreased significantly when cimetidine was coadministered. Coadministered cimetidine increased $AUC_t$ and $C_{max}$ of theophylline. All subjects were genotyped using PCR-RFLP methods to evaluate the differences in metabolic capacity in accordance with CYP1A2 genotypes, but no mutant genotype was found. This suggests that metabolic capacities were not significantly affected by CYP1A2 genotypes among subjects. In conclusion, disposition of theophylline was significantly affected by coadministered cimetidine. Further evaluation with well-designed drug interaction study in accordance with various genotype of CYP1A2 is needed.

• Journal of Life Science
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• v.23 no.8
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• pp.1064-1072
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• 2013

Circadian rhythm is controlled by hormonal oscillations governing the physiology of all living organisms. In mammals, the main function of the pineal gland is to transform the circadian rhythm generated in the hypothalamic suprachiasmatic nucleus into rhythmic signals of circulating melatonin characterized by a largely nocturnal increase that closely reflects the duration of night time. The pineal gland has lost direct photosensitivity, but responds to light via multi-synaptic pathways that include a subset of retinal ganglion cells. Rhythmic control is achieved through a tight coupling between environmental lighting and arylalkylamine-N-acetyltransferase (AANAT) expression, which is the rhythm-controlling enzyme in melatonin synthesis. Previous studies on the nocturnal expression of AANAT protein have described transcriptional, post-transcriptional, and post-translational regulatory mechanisms. Molecular mechanisms for dependent AANAT expression provide novel aspects for melatonin's circadian rhythmicity. Extensive animal research has linked pineal melatonin for the expression of seasonal rhythmicity in many mammalian species to the modulation of circadian rhythms and to sleep regulation. It has value in treating various circadian rhythm disorders, such as jet lag or shift-work sleep disorders. Melatonin, also, in a broad range of effects with a significant regulation influences many of the body's physiological functions. In addition, this hormone is known to influence reproductive, cardiovascular, and immunological regulation as well as psychiatric disorders.

• Economic and Environmental Geology
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• v.46 no.2
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• pp.165-178
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• 2013

This study is for the genetic differences of two closed asbestos mines from Jeongjeon and Ocheon areas in Boryoung, Chungnam. They are mined asbestos for past several decades. Host rocks are serpentinites for Jeongjeon mine and dolomites for Ocheon mine. Asbestos samples and their host rocks are collected from the field trips and examined with microscopes and FESEM, and analysed with XRD and EDX to confirm for the type and/or compositions of the minerals. The asbestos occur as layers, cracks and fractures assummed as a pathway of the hydrothermal water, but show different characteristics. The serpentinites from the Jeongjeon mine contain chrysotile, tremolite and actinolite asbestos. Non-asbestos minerals including tremolite and actinolite were also found. The chrysotiles occur as a cross fiber or slip fiber at veins and along cracks of several mm to cm thickness. Tremolite and actinolite asbestos occur along cracks and fractures of several cm to ten cm thickness. It suggests that the asbestos from Jeongjeon area were formed by the reactions between serpentinite and hydrothermal water. The dolomites of the Ocheon mine only contain tremolite and actinolite asbestos. The asbestos occur along layers, cracks and fractures, suggestive of asbestos from Ocheon area formed by the reactions between dolomite and hydrothermal waters influxed along layers, cracks and fractures. Overall results suggest that two asbestos mines showing different host rocks are located in a Boryoung area. They show a different type of asbestos minerals, reflecting variety of petrogeneses.

• Journal of Veterinary Clinics
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• v.31 no.5
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• pp.361-366
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• 2014

The aim of this study was to determine if vaccines containing CPV-2 or CPV-2b provided protection against challenge with a recent Korean CPV-2a isolate. Twenty mongrel pups aged 9 weeks old were used. The commercial CPV-2 or CPV-2b vaccines were administered to each of the 8 pups thrice every 3 weeks, respectively. Two weeks after the last vaccination, all pups were challenged with CPV-2a (VR00174 strain) $1{\times}10^6\;TCID_{50}$. Clinical signs, fecal excretion of challenged CPV, and serological response of pups were observed for 2 weeks after challenge. All vaccinated pups did not display any clinical signs of disease after challenge with Korean CPV-2a isolate, whereas all non-vaccinated pups exhibited mucoid or hemorrhagic diarrhea, vomiting and anorexia. In all non-vaccinated pups, the virus could be detected in feces from 4 days after challenge, whereas in vaccinated pups, no evidence of viral excretion could be detected. Two of 4 non-vaccinated pups died 6 days after the challenge. This study showed that the two commercial CPV-2 and CPV-2b vaccines were effective in preventing infection and/or disease caused by the Korean CPV-2a isolate.

• Korean Chemical Engineering Research
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• v.45 no.4
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• pp.378-383
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• 2007

A novel fabrication method for the multi-component metal oxides such as zirconium titanate($Zr_xTi_{1-x}O_2$) has been suggested, which would yield the uniform film characteristics and control the film composition at relatively low process temperature. The method has the basic concept that firstly layer-by-layer structure is constructed with the primitive oxide layers, which are components of the desired multi-component oxides, and secondly the film is annealed at appropriate thermal conditions for the transformation to a single-phase multi-component oxides. In this study, PRTMOCVD(pulsed rapid thermal metalorganic chemical vapor deposition) possessing the superior thickness controllability was introduced to prepare $ZrO_2$ and $TiO_2$ thin film for zirconium titanate. Single-phase zirconium titanate thin films have been prepared successfully by the interdiffusion of oxide multilayers having several alternating layers of $ZrO_2$ and $TiO_2$. The Zr/Ti ratio of zirconium titanate could be controlled easily by altering the thickness of $ZrO_2$ and $TiO_2$ thin film.

• Weed & Turfgrass Science
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• v.1 no.4
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• pp.69-75
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• 2012

In response of fungicides for control of gray snow mold, isolates of Typhula incarnata were collected from three golf courses in 2012 Yongpyeong, Korea and tested for sensitivity to propiconazole, tebuconazole and azoxystrobin fungicides. Four discriminatory concentrations were used to detect in vitro sensitivity of 50 isolates. Mean 50% effective concentration inhibiting mycelial growth ($EC_{50}$) values for tebuconazole was the lowest among the three fungicides. The $EC_{50}$ value of tebuconazole ranged from 0.0005 ${\mu}g\;ml^{-1}$ to 0.014 ${\mu}g\;ml^{-1}$ with a mean of 0.0048 ${\mu}g\;ml^{-1}$. The mean $EC_{50}$ values of propiconazole in triazole family was 0.5825 (0.78-1.651) ${\mu}g\;ml^{-1}$. $EC_{50}$ value of azoxystrobin ranged from 0.0017 ${\mu}g\;ml^{-1}$ to 0.131 ${\mu}g\;ml^{-1}$ with a mean of 0.0278 ${\mu}g\;ml^{-1}$. There was no correlation among $EC_{50}$ values for propiconazole, azoxystrobin and tebuconazole indicating no cross-resistance relationships with each other. Results of this study were confirmed no resistance isolates in vitro sensitivity of T. incarnata of three fungicides in Yongpyeong.

• Journal of Conservation Science
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• v.37 no.5
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• pp.411-425
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• 2021

The Stupa of State Preceptor Jigwang from Beopcheonsa Temple Site in Wonju (National Treasure) is a representative stupa of the Goryeo Dynasty, with outstanding Buddhist carvings and splendid patterns, clearly indicating its honoree and year of construction. However, it was destroyed by bombing during the Korean War (1950-1953) and repaired and restored with cement and reinforcing bars in 1957. The surface condition of the original stone shows long-term deterioration due to the m ortar used in past restorations. In order to identify the exact causes of deterioration, the m ortar and surface contaminants on the original stone were analyzed. Portlandite, calcite, ettringite, and gypsum from the mortar were identified, and its ongoing deterioration was observed through pH measurements and the neutralization reaction test. Analysis of surface contaminants identified calcite and gypsum, both poorly water-soluble substances, and their growth in volume among rock-forming minerals was observed by microscopy. Based on those results, semi-quantitative analysis of Ca and S contents significantly influencing the formation of salt crystals was conducted using P-XRF to analyze the basis of surface deterioration, and cross-validation was performed by comparing the body stone affected by the mortar and the upper stylobate stone unaffected by the mortar. Results indicate that the elements are directly involved in the surface deterioration of the body stone.

• Journal of the Korean Association of Geographic Information Studies
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• v.25 no.3
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• pp.74-99
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• 2022

Surface ozone is produced by photochemical reactions of nitrogen oxides(NOx) and volatile organic compounds(VOCs) emitted from vehicles and industrial sites, adversely affecting vegetation and the human body. In South Korea, ozone is monitored in real-time at stations(i.e., point measurements), but it is difficult to monitor and analyze its continuous spatial distribution. In this study, surface ozone concentrations were interpolated to have a spatial resolution of 1.5km every hour using the stacking ensemble technique, followed by a 5-fold cross-validation. Base models for the stacking ensemble were cokriging, multi-linear regression(MLR), random forest(RF), and support vector regression(SVR), while MLR was used as the meta model, having all base model results as additional input variables. The results showed that the stacking ensemble model yielded the better performance than the individual base models, resulting in an averaged R of 0.76 and RMSE of 0.0065ppm during the study period of 2020. The surface ozone concentration distribution generated by the stacking ensemble model had a wider range with a spatial pattern similar with terrain and urbanization variables, compared to those by the base models. Not only should the proposed model be capable of producing the hourly spatial distribution of ozone, but it should also be highly applicable for calculating the daily maximum 8-hour ozone concentrations.

• Korean Journal of Clinical Laboratory Science
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• v.55 no.3
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• pp.132-142
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• 2023

Human leukocyte antigen (HLA) typing was performed in the diagnostic immunology laboratory of the Seoul National University Hospital. Among 611 HLA-DR tests, specific bead reactions suspected of being false positive and false negative in Lot 20 reagents were found. Therefore, we aimed to identify the factors causing cut-off corrections by examining cases where cut-off corrections were not made for 533 test results and cases where cut-off corrections were made for 78 cases after the cut-off corrections of specific beads. Frequency analysis was conducted to verify the demographic characteristics, and descriptive statistics were used to assess the humidity in the laboratory as a variable. Cross-tabulation was done to examine the association between cut-off corrections and demographic characteristics. Independent samples t-tests were conducted to verify the difference in humidity based on cut-off corrections. Finally, logistic regression analysis was conducted to examine the relationship between humidity levels and the rate of cut-off corrections, and results showed as the humidity level in the laboratory highs, the number of cut-off corrections decreased by a factor of 0.986. This suggests cut-off corrections rate increases when the humidity lowers. Therefore, it indicates that humidity in the laboratory is also a factor that affects HLA typing results.

• Journal of Gastric Cancer
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• v.7 no.1
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• pp.9-15
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• 2007

Purpose: DNA methylation is an important epigenetic factor in tumorigenesis. We hypothesized that polymorphism of the promoter of the DNA methyltransferase 3b (DNMT3b) genes, which are responsible for regulating the methylation status of tumor suppressor genes, are associated with increased risk of gastric cancer. Materials and Methods: In this hospital-based case-control study, to determine the role of this polymorphism of the promoter of DNA methyltransferase 3b (DNMT3b) genes in gastric cancer, we genotyped 176 cases and 70 control subjects. To determine the genotype, we used a polymerase chain reaction restriction fragment length polymorphism assay. We compared alleles and genotypes between the two groups and revealed an association of DNMT3b promoter polymorphism with increased risk of gastric cancer in the Korean population. Results: Genotype frequencies were 14.8% (Cytosine-Cytosine), 71.6% (Cytosine-Thymine), and 13.6% (Thymine- Thymine) in the case patients and 40.0% (Cytosine-Cytosine), 42.9% (Cytosine-Thymine), and 17.1% (Thymine-Thymine) in the control subjects, respectively. Compared with CC homozygotes, CT heterozygotes had a 4.523-fold increased risk (OR, 2.13; 95% CI, 2.324~8.803), and the TT homozygotes had a 2.154-fold elevated risk (OR, 1.42; 95% CI, 0.899~85.165). For the T variant genotype (CT+TT), there was a 3.846-fold increased risk (OR, 1.88; 95% CI, 2.040~7.251). However, no significance was observed in the genotype distributions of both polymorphisms according to histopathology, stage of stomach cancer. The Ssame results were observed with Helicobacter infection. Conclusion: DNMT3b promoter polymorphism, especially the T variant genotype, is associated significantly with thean increased risk of gastric cancer.