• Korean Journal of Environmental Biology
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• v.26 no.3
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• pp.252-263
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• 2008

The purpose of this study was to determine trophic state, based on nutrients (TN, TP), transparency (SD), and chlorophyll-${\alpha}$ (Chl) and identify their empirical relations of TN-Chl, TP-Chl and Chl-SD depending on the dataset used along with dynamics of conductivity and suspended solids. Analysis of trophic states showed that more than half of 36 reservoirs were judged as eutrophic-hypertrophic conditions depending on the trophic variables. Seasonal values of TP varied by nearly 500% and showed greater in August than any other months. In contrast, TN varied within less than 90% and all monthly mean values of TN were never fall less than 1.2 mg L$^{-1}$ indicating low seasonal variations and high ambient concentrations (eutrophic-hypertrophic state). Analysis of empirical relations in the trophic variables showed that transparency had greater functional relations with Chl (R$^2$=0.31, p<0.001) than TP (R$^2$=0.15, p<0.001) and TN (R$^2$=0.20, p<0.001). Ratios of TN : TP in the ambient water indicated that most reservoirs showed a potential phosphorous limitation on the algal growth. Thus, algal biomass, based on Chl values, was more regulated by phosphorous than nitrogen. Analysis of linear regression model, based on log-transformed annual mean values, showed that only 30% in the variation of Chl was explained by TP (R$^2$=0.295, p=0.001, n=36) and 15% by TN (R$^2$=0.151, p=0.019, n=36). However, linear regression model, based on individual system, showed that Chl-TP model had strong positive relations (R$^2$=0.62, p=0.002, n=12), whereas the model had no any relations (p=0.892, n=12). Overall, our data suggested that averaging effect in the empirical model developments may influence the significance in the statistical analysis.

• Korean Journal of Biological Psychiatry
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• v.21 no.3
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• pp.99-106
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• 2014

Objectives Previous studies suggest that the cannabinoid receptor 1 (CNR1) gene could be an important candidate gene for schizophrenia. According to linkage studies, this gene is located on chromosome 6q14-q15, which is known to harbor the schizophrenia susceptibility locus (locus 5, SCZ5, OMIM 803175). The pharmacological agent delta-9-tetrahydrocannabinol (${\Delta}$-9-THC) seems to elicit the symptoms of schizophrenia. The association between CNR1 polymorphisms and schizophrenia is actively being investigated, and some studies have linked the AAT-trinucleotide repeats in CNR1 to the onset of schizophrenia. In this study, we have investigated the association between the AAT-trinucleotide repeats in CNR1 and schizophrenia by studying schizophrenia patients and healthy individuals from Korea. Methods DNA was extracted from the blood samples of 394 control subjects and 337 patients diagnosed with schizophrenia (as per the Diagnostic and Statistical Manual of Mental Disorders, fourth edition criteria). After polymerase chain reaction amplification, a logistic regression analysis, with age and gender as the covariates, was performed to study the variations in the AAT-repeat polymorphisms between the two groups. Results In total, 8 types of trinucleotide repeats were identified, each containing 7, 8, 10, 11, 12, 13, 14, and 15 repeats, respectively. $(AAT)_{13}$ allele was most frequently observed, with a frequency of 33.6% and 31.6% in the patient and control groups, respectively. The frequency of the other repeat alleles in the patient group (in the decreasing order) was as follows : $(AAT)_{13}$ 33.6%, $(AAT)_{14}$ 21.6%, $(AAT)_{12}$ 18.5%, and $(AAT)_{7}$ 11.1%. The frequency of the repeat alleles in the control group (in the decreasing order) was as follows : $(AAT)_{13}$ 31.6%, $(AAT)_{14}$ 24.5%, $(AAT)_{12}$ 17.2%, and $(AAT)_{7}$ 11.6%. However, there were no significant differences in the AAT-repeat polymorphisms of the CNR1 gene between the patient group and the control group. Conclusions Although our study revealed no significant association of the AAT-repeat polymorphism of the CNR1 gene with schizophrenia, it will serve as a good reference for future studies designed to examine the cannabinoid hypothesis of schizophrenia.

• Journal of the Korean Institute of Landscape Architecture
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• v.41 no.6
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• pp.96-106
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• 2013

The aim of this study was to reveal the advantages and disadvantages of Terelj Mongolian National Park based on the impressions of foreign and domestic travelers, and subsequently suggest supporting ideas to make this tourist attraction more enjoyable for travelers. A statistical program(SPSS 20.0) and an IPA matrix method were used to reveal the impressions of travelers and the results showed the following ideas. First, we made the technical analyses to demonstrate the characteristics of the current natural scenery which travelers want to see and the results indicated that both Korean and Mongolian travelers overall were not satisfied and the Park was not as they had imagined. The second part of the research highlighted the differences between the impressions held by Mongolian and Korean travelers, which showed dissimilarities in cultural resources, food, variety of events, cultural functions and parking, all of which were shown as important criteria in sightseeing. The variations were found in scenes of nature, variety of programs, and food, areas which revealed and were very important in the overall satisfaction of travelers. Third, the IPA method was used for analyze the advantages and disadvantages of Terelj National Park. The Mongolian travelers nominated the width of the road, cleanliness, variety of events and parking are the most essential things to feel satisfied, but Koreans selected safety of travel, accommodation, the width of the road and cleanliness. Finally, we analyzed the feelings of the travelers at the end of their trip. The Mongolian travelers preferred the area resource and environment convenience to feel satisfaction. For Korean travelers, the area resource is the most important when choosing travelling sights. Based on these results, if we take responsibility to protect the beauty of nature, and create a sightseeing place using natural sources, while also making more comfortable accommodations and improving the services, it can be a more unique place than others and lead to greater overall satisfaction for travelers.

• Journal of Korean Ophthalmic Optics Society
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• v.17 no.3
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• pp.265-272
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• 2012

Purpose: To compare the results on myopia correction with reverse geometry lenses, effects of wearing reverse geometry lenses were evaluated for the children with low-level and high-level myopia. Methods: The research investigated the corrective effects of having worn reverse geometry lenses for one week, one month, three months and six months on a total of thirty-six persons (sixty-two eyes) between the ages of seven and fifteen, divided into three groups by the degree of their myopia; nineteen eyes(Group One) with myopia of -2.00 D and under, twenty-eight eyes(Group Two) with myopia between -2.25 D and -4 D, and fifteen eyes(Group Three) with myopia of -4.25 D and above; as shown by changes in uncorrected vision and the degree of refraction in the corneal topography, and tested for statistical similarity among the pursued results. Results: After wearing reverse geometry lenses, Group One showed an improvement in vision of 0.5, from 0.45 to 0.95, after one week, and improvements to 0.91 after one month and 1.02 after three months but, after six months, the group's vision regressed to 0.95. Group Two showed an improvement in vision of 0.43, from 0.34 to 0.77, after one week of wearing and to 0.91 after one month, to 0.97 after three months and this was statistically maintained through the remainder of six months. Group Three showed an improvement in vision of 0.55, from 0.15 to 0.7, after wearing for one week, to 0.87 after one month and to 0.91 after three months but saw a regression to 0.86 after six months. The average Sim K (simulated keratometry reading) value for Group One started from $42.84{\pm}1.17D$ and decreased to $41.48{\pm}0.98D$ after one week of wearing and continued declining through three months before increasing during the remainder of six months. Group Two began from $42.91{\pm}1.57D$ and recorded $41.78{\pm}1.58 D$ after one week, continuing the decline through three months before increasing during the remainder of six months. Group Three began at $42.64{\pm}1.64D$ and showed its Sim K value decrease to $40.77{\pm}1.20D$ after one week of wearing, increase after one month and decrease after three months and continue the decline through the remainder of six months. Conclusions: From the results of this study, wearing reverse geometry lenses had myopia-correcting effects after one week of wearing. Although there were variations in the time for such effect to take place but myopia-correcting effects were evident in all test groups.

• Journal of the Korean Society of Radiology
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• v.1 no.1
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• pp.17-23
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• 2007

Background: Cerebrovascular diseases are known to show different patterns of incidence among regions and races. Therefore, it is very important to determine the incidence pattern of a specific area in order to diagnose, treat and prevent cerebrovascular diseases. The objective of the present study is to analyze quantitatively the incidence ratios of hemorrhagic and ischemic cerebrovascular diseases by season, by gender and by age. Methods: The subjects of this study were 1603 patients hospitalized for hemorrhagic or ischemic cerebrovascular diseases at the Department of Neurosurgery or the Department of Neurology of a University Hospital. Statistical analysis of data used Excel 2003 of Microsoft, and t-test was conducted using ORIGIN 6.0 of MICROCAL. Results: In the subjects, the incidence ratios of hemorrhagic and ischemic cerebrovascular diseases for four years, the period of this research, were 38.55% and 61.45%, respectively. The mean and standard deviation of age when hemorrhagic cerebrovascular diseases occurred were 58.20 and 12.60, respectively, and the percentages of subjects in their 40s, 50s, 60s and 70s were all around 20%. On the contrary, the mean and standard deviation of age when ischemic cerebrovascular diseases occurred were 65.01 and 13.59, respectively. The average age of patients with ischemic cerebrovascular diseases was older than that of patients with hemorrhagic brain diseases, and the percentages of those in their 60s, 70s and 80s were 15.53%, 37.06% and 27.72%, respectively. The season when hemorrhagic cerebrovascular diseases appeared most frequently was winter, which was followed by summer, spring and autumn. The season when hemorrhagic cerebrovascular diseases appeared most frequently was spring, which was followed by summer, winter and autumn. Conclusions: In this study, the incidence rates of hemorrhagic and ischemic cerebrovascular diseases were 38.55% and 61.45%, showing the rising percentage of ischemic cerebrovascular diseases. For making adequate prevention and disease control plans, it is considered necessary to make a long-term epidemiological investigation of cerebrovascular diseases.

• Journal of the korean academy of Pediatric Dentistry
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• v.28 no.2
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• pp.271-280
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• 2001

The aim of the present study was to analyze relationship between dietary habits and dental caries experience in preschool children. All 143 boys and 124 girls living in a chonju city were investigated dmf index by dentists through oral examination and dietary habit by children's mothers through questionaires such as infant diets and food preferences. The statistical analysis were performed to evaluate whether variations in dietary habits are related to dental caries experience. The obtained results were as follows; 1. The average dmf index scores of all children were examined $2.92{\pm}1.05$. The girls had higher than the boys, but no significant differences between the genders were seen the dmf index(P>0.05). 2. The higher were their age of children, the higher dmf index was investigated. The dmf index of 5 and 6-yr old childrens was higher than that in 3 and 4-yr old children(P<0.05). 3. No significant difference was found between the present of mother's occupation (P>0.05) and type of infant dietary habits(P>0.05). 4. The fruits and sea weeds were showed high degree of preference and fats and vegetables were showed low degree generally. Among 13 food groups, there was no significant difference between boys and girls except for sea weeds(P>0.05). 5. Among 13 food groups, the dmf index was positively associated with sugars(r=0.3854, P<0.05), dairy products(r=0.4328, P<0.05) and soft drinks(r=0.2586, P<0.05), and negatively associated with other food groups.

• Journal of dental hygiene science
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• v.10 no.4
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• pp.241-250
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• 2010

The purpose of this study, which was processed from March $22^{nd}$ to April $9^{th}$ of 2010, was to figure out recognition, well-formed instructions, and Practical application about dental hygiene devices based on the dental health characteristics of 350 adults who dwell in Busan and Gyeongnam regions. Also, this study recommended the adults to use dental hygiene devices and provided such devices to help individuals take care of their dental health at home. The collected data was statistically processed with a statistics SPSS (Statistical Packages for Social Science 14.0. SPSS Inc. USA) program. First of all, in order to demonstrate the characteristics of the sample population statistics and that of the descriptive data, frequency analysis was performed and to find out the relationship between variations of the dental health, Chi-squared test through Crosstabs was operated. According to the study, recognition and Practical application of dental hygiene devices were very low. Therefore, public announcement about necessity and effectiveness of such devices should be reinforced nationwide and instructions on choosing the right device and using of the dental hygiene devices based on patients' conditions by dental hygienic human efforts gathered from dental health organization should be carried out.

• Restorative Dentistry and Endodontics
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• v.24 no.2
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• pp.310-321
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• 1999

In this in vitro study, confocal laser scanning microscopic morphology of dentin-resin interface and its relationship to shear bond strength were investigated after the exposed dentin surfaces were treated with 3 different kinds of dentin adhesive systems[three-step; Scotchbond Multi-Purpose Plus(SMPP), self-priming bonding resin; Single Bond(SB), self-etching primer; Clearfil Liner Bond 2(LB2)]. 52 extracted human molar teeth without caries and/or restorations. The experimental teeth were randomly divided into three groups of seventeen teeth each. In five teeth of each group, class V cavities(depth: 1.5mm) with 900 cavosurface angles were prepared at the cementoenamel junction on buccal and lingual surfaces. Bonding resins of each dentin adhesive system were mixed with rhodamine B. Primer of SMPP was mixed with fluorescein. In group 1. the exposed dentin was conditioned with etchant, applied with above primer and bonding resin of SMPP. In group 2, with etchant and self-priming bonding agent of SB. In group 3, with self-etching primer and bonding agent of LB2. After treatment with dentin adhesive systems, composite resin were applied and photocured. The experimental teeth were cut longitudinally through the center line of restoration and grounded so that about $90{\mu}m$-thick wafers of buccolingually orientated dentin were obtained. And, $70{\sim}80{\mu}m$-thick wafers sectioned horizontally, thus presenting a dentinal tubules at 900 to the cut surface of a remaining tooth, were obtained. Primer of SMPP mixed with rhodamine B was applied to these wafers. Confocal laser scanning microscopic investigations of these wafers were done within of 24 hours after treatment. To measure shear bond strength, the remaining twelve teeth of each group were grounded horizontally below the dentinoenamel junction, so that no enamel remained. After applying dentin adhesive systems on the dentin surface, composite was applied in the shape of cylinder. The cylinder was 5mm in diameter, and 2mm in thickness. Shear bond strength was measured using Instron with a cross-head speed of 0.5mm/min. It was concluded as follows ; 1. Hybrid layer of SMPP(mean: $4.56{\mu}m$) was thicker than that of any other groups. This value was not statistically significant thicker than that of SB(mean: $3.41{\mu}m$, p>0.05), and significant thicker than that of LB2(mean: $1.56{\mu}m$, p<0.05). There was a statistical difference between SB and LB2(p<0.05). 2. Although there were variations in the length of resin tag even in a sample, and in a group, most samples in SMPP and SB showed resin tags extending above $20{\mu}m$. But samples in LB2 showed resin tags of $10{\mu}m$ at best. 3. Besides primer's infiltration into demineralized peritubular dentin and dentinal tubules, fluorophore of primer was detected in the lateral branches of dentinal tubules. 4. All groups demonstrated statistically significant differences from one another(p<0.05), with shear bond strengths given in descending order as follows: SMPP(18.3MPa), SB(16.0MPa) and LB2(12.4MPa). 5. LB2 having thinnest hybrid layer($1.56{\mu}m$) showed the lowest shear bond strength(12.4MPa).

• Korean Journal of Ecology and Environment
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• v.48 no.2
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• pp.95-107
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• 2015

In order to identify long-term trends of water quality parameters in Lake Kyeongpo, Mann-Kendall test, Sen's slope estimator and linear regression were applied on data, with 15 parameters from three different sites and rainfall, monitored once in every two months from March to November during 1998~2013. Seasonal variation analysis only used Mann-Kendall test and Sen's slope estimator. Analysis result showed that salinity, transparency and nutrient variables (total phosphorus, dissolved inorganic phosphorus, total nitrogen, nitrate nitrogen, ammonia nitrogen) were only parameters having statistically significant trend. In linear regression analysis, salinity (surface and bottom layer of all sites) and transparency (only at site 1), were figured out with statistically significant increasing trend, while in non-parametric statistical method, salinity and transparency in all sites (surface, middle, deep) were figured out with statistically significant increasing trend. Water quality parameters showing statistically significant decreasing trends were dissolved oxygen (surface layer of site 1 and bottom layer of sites 2 and 3), total phosphorus (sites 1 and 2), dissolved inorganic phosphorus, total nitrogen, nitrate nitrogen and ammonia nitrogen in the linear regression analysis and, dissolved oxygen (bottom layer of all sites), total phosphorus, dissolved inorganic phosphorus, total nitrogen, nitrate nitrogen and ammonia nitrogen in the non-parametric method. Seasonal trend analysis result showed that salinity, turbidity, transparency and suspended solids in spring, salinity, transparency, nitrate nitrogen and suspended solids in summer and temperature, salinity, transparency and suspended solids in fall were the variables depending on the season with increasing trends. In general, rainfall during the research period showed decreasing trend. The significant reduction trends of nutrients in Lake Kyeongpo were believed to be related to lagoon restoration and water management project run by Gangneung city and under-water wear removal, but further detailed studies are needed to know the exact causes.

• Journal of Korean Society of Forest Science
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• v.100 no.2
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• pp.226-231
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• 2011

Ulmus davidiana var. japonica is a deciduous tree species used for traditional medicine. This study was conducted to investigate the variation of samara, seed, germination and growth characteristics among populations and among individuals within five natural populations of U. davidiana var. japonica distributed in Korea. The ten characteristics of samara and seed, the three germination behaviors as well as the two growth traits were studied in samaras collected from total 32 trees. Statistical analysis of all characteristics showed that there were significant differences among populations as well as among individuals within populations. In this study, the mean characteristics of this species were 13.0 mm in samara length, 9.7 mm in samara width, 1.37 in samara index, 0.015 g in samara weight, 3.07 mm in samara stalk length, 3.85 seed length, 2.66 mm in seed width, 1.46 in seed index, 1.29 mm seed thickness, 0.0062 g in seed weigh, 34.8% in germination percentage, 8.6 days in mean germination time, 3.5 ea./day in gemination rate, 37.7 cm in height and 4.90 mm in root collar diameter. Especially, coefficients of variations in samara weight, germination percentage, germination rate, height and root collar diameter were relatively high (${\geq}30.0%$) compared to other traits. There was no significant relationship between population association and geographical distribution. The results of principal component analysis for 15 characteristics showed that primary four principal components (PC's) explained 100% of the total variation. The first PC accounted for 41.8% of the variability which correlated with morphological traits, the second PC accounted for 32.9% of the variability which correlated with germination behaviors and the third PC accounted for 16.3% of the variability which correlated with growth traits.