• The Journal of Korean Academy of Prosthodontics
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• v.52 no.1
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• pp.27-33
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• 2014

Purpose: The purpose of this study was to investigate the food impaction between implant prostheses and adjacent natural teeth. Materials and methods: For this study, 51 patients with food impaction were selected and investigated mobility, tightness of contact area, gingival index, plaque index, attachment loss, alveolar bone level, proximal caries, marginal ridge distance and occlusal relationships. Results: Food impaction was found in the upper teeth (60.7%) more than the lower teeth (39.2%). Food impaction was occurred on mesial side of implant prostheses (86.2%) more than distal side (13.7%). Food impaction was mostly found in loose or open contact area (94.2%). Food impaction was frequent on stepped relationship between implant and adjacent teeth. Conclusion: Treatment plan should include proper adjacent and antagonistic occlusal plane and occlusal surface, to prevent food impaction, and the plan should include less adjacent tooth mobility with proper tightness between implant prostheses and adjacent teeth.

• Fisheries and Aquatic Sciences
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• v.10 no.1
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• pp.30-36
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• 2007

We present age and growth data for Ilisha elongata, based on 363 specimens caught in 1999 and 2000 around Jeju Island and the southwest coast of Korea. Scale and ring radii of each ring group showed a direct one-to-one relationship, with ring radius increasing as scale radius increased. The relationship between fork length and scale radius was FL=39.553SR+60.935 for females, FL=39.474SR+54.026 for males, and FL=39.608SR+57.547 for both sexes. Monthly changes in the marginal index indicated that a new ring appears once each year (in July). Maximum age, mean age and mean fork length of fish were 10 years, 5.0 years, and 349mm, respectively. Von Bertalanffy's growth equations were $FL_t=495.4{\times}[1-\exp(-0.2586(t+0.6487))]$ for fork length (mm) and $W_t=1,112.5{\times}[1-\exp(-0.2586(t+0.6487))]^{2.874}$ for body weight (g) for both sexes. Monthly changes in the gonadosomatic index (GSI) indicated that the spawning period was in June and July, which corresponded closely with ring formation time. Differences in monthly GSI changes in 1999 and 2000 may be related to water temperature variation. Fecundity ranged from 5,664 to 176,290 eggs per individual (n=43, fork length 264-470mm). The relationship between fecundity(F) and fork length was $F=7.7{\times}10^{-7}{\times}FL^{4.9269}$.

• Journal of Periodontal and Implant Science
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• v.50 no.4
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• pp.251-259
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• 2020

Purpose: This randomized controlled study aimed to evaluate the effects of an electric toothbrush with 3 colors of light-emitting diodes (LEDs) on antiplaque and bleeding control. Methods: This randomized, placebo-controlled, double-blinded, parallel-group clinical trial included 50 healthy adults with gingivitis, who were randomly assigned to 2 groups. The experimental group used electric toothbrushes with 3 colors of LEDs and the control group used the same electric toothbrush as the experimental group, but with LED sources with one-hundredth of the strength. The subjects used the electric toothbrush 3 times a day for 4 minutes each time. As clinical indices, bleeding on marginal probing (BOMP), the Löe-Silness gingival index (GI), and the Turesky-Quigley-Hein plaque index (QHI) were assessed at baseline, at 3 weeks, and at 6 weeks. Results: There were significant decreases in all clinical indices (BOMP, GI, QHI) in both the experimental and control groups compared to baseline at 3 weeks and at 6 weeks. In a comparison between the experimental and control groups, no statistically significant differences were observed for any clinical indices at 3 weeks (P>0.05). However, at 6 weeks, statistically significant differences were observed between the experimental and control groups in BOMP and GI, which are indicators of gingival inflammation (P<0.05). Conclusions: This study demonstrated that an electric toothbrush combined with 3-color LEDs reduced gingival bleeding and inflammation after 6 weeks.

• Journal of Korean Society on Water Environment
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• v.37 no.2
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• pp.114-127
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• 2021

Water pollution in the lower reaches of the Namhan River is getting worse due to drought and a decrease in water quantity due to climatic changes and hence is affecting the water quality of Paldang Lake. Accordingly, we have used a water quality index (WQI) and statistical analysis in this study to identify the characteristics of the water quality in the lower reaches of the Namhan River, the main causes of water pollution, and tributaries that need priority management. Typically, 10 items (WT, pH, EC, DO, BOD, COD, SS, T-N, T-P, and TOC) were used as the water quality factors for the statistical analysis, and the matrix of data was set as 324 × 10·1. The correlation analysis demonstrated a strong correlation between Chemical Oxygen Demand (COD) and T-P with a high statistical significance (r=0.700, p<0.01). Furthermore, the result of principal component analysis (PCA) revealed that the main factors affecting the change in water quality were T-P and organic substances introduced into the water by rainfall. Based on the Mann-Kendall test, a statistically significant increase in pH was observed in SH-1, DL, SH-2, CM, and BH, along with an increase in WQI in SH-2 and SM. BH was identified as a tributary that needs priority management in the lower reaches of the Namhan River, with a "Somewhat poor" (IV) grade in T-P, "Fair" grade in WQI, and "Marginal" grade in summer.

• Journal of Periodontal and Implant Science
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• v.54 no.2
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• pp.85-95
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• 2024

Purpose: Developmental endothelial locus-1 (DEL-1) plays a role in regulating neutrophil migration within the periodontium. The objective of this study was to evaluate the levels of DEL-1 in saliva and gingival crevicular fluid (GCF), as well as the number of neutrophils in patients with periodontitis. Methods: Forty systemically healthy, non-smoking periodontitis patients participated in this study. Clinical periodontal parameters, including the plaque index, probing pocket depth (PPD), clinical attachment level, bleeding on probing, modified sulcular bleeding index, and marginal bone level, were measured. Levels of DEL-1, interleukin (IL)-1β, IL-6, and IL-8 in unstimulated saliva samples, as well as DEL-1 in the GCF of 3 teeth from each participant, were assessed. Neutrophil counts in oral rinse and GCF samples were recorded. Spearman correlation coefficients were used to examine the correlation between protein levels, clinical parameters, and neutrophil quantities. Participants were divided into 2 age groups (those under 50 years and those 50 years or older) in order to investigate potential age-related differences. Results: DEL-1 levels in the GCF showed a negative relationship with PPD (sum). Neutrophils in oral rinse samples were positively correlated with PPD, IL-8, and IL-1β levels. Neutrophils in GCF exhibited a positive correlation with PPD (sum). Salivary DEL-1 levels showed correlations with IL-8 and IL-1β, but not with the clinical parameters of periodontitis. Conclusions: The negative relationship observed between PPD and GCF DEL-1 levels is consistent with the proposed protective role of DEL-1.

• Journal of Microbiology and Biotechnology
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• v.34 no.6
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• pp.1239-1248
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• 2024

Peatlands are marginal agricultural lands due to highly acidic soil conditions and poor drainage systems. Drought stress is a big problem in peatlands as it can affect plants through poor root development, so technological innovations are needed to increase the productivity and sustainability of upland rice on peatlands. Rhizobacteria can overcome the effects of drought stress by altering root morphology, regulating stress-responsive genes, and producing exopolysaccharides and indole acetic acid (IAA). This study aimed to determine the ability of rhizobacteria in upland rice to produce exopolysaccharides and IAA, identify potential isolates using molecular markers, and prove the effect of rhizobacteria on viability and vigor index in upland rice. Rhizobacterial isolates were grown on yeast extract mannitol broth (YEMB) medium for exopolysaccharides production testing and Nutrient Broth (NB)+L-tryptophan medium for IAA production testing. The selected isolates identify using sequence 16S rRNA. The variables observed in testing the effect of rhizobacteria were germination ability, vigour index, and growth uniformity. EPS-1 isolate is the best production of exopolysaccharides (41.6 mg/ml) and IAA (60.83 ppm). The isolate EPS-1 was identified as Klebsiella variicola using 16S rRNA sequencing and phylogenetic analysis. The isolate EPS-1 can increase the viability and vigor of upland rice seeds. K. variicola is more adaptive and has several functional properties that can be developed as a potential bioagent or biofertilizer to improve soil nutrition, moisture and enhance plant growth. The use of rhizobacteria can reduce dependence on the use of synthetic materials with sustainable agriculture.

• Economic and Environmental Geology
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• v.19 no.spc
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• pp.175-191
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• 1986

The Geodo granodiorite intruded into the Joseon Supergroup is fine-grained at the marginal part, and medium-grained and more leucocratic at the central part. The Quartz monzonite porphyry intruded inte Precambrian granite and Geodo granodiorite has abundant plagioclase phenocryst. The Imog granite intruded into the Yulri Group and the Joseon Supergroup is mediumgrained biotite granite with partly pinkish feldspar phenocryst. The K/Ar ages obtained from the biotite of the Geodo granodiorite and Imog granite are Early ($111{\pm}1{\sim}107{\pm}1$ Ma) and Late ($93{\pm}1{\sim}92{\pm}1$ Ma) Cretaceous, respectively. The K/Ar sericite age of the quartz-sericite zone of the lower Jangsan quartzite occuring in the western area gave much younger age (about 170 Ma) than that of the Jangsan quartzite, that might be reset due to the regional metamorphism of the Daebo orogeny. The granitic rocks of the area are felsic to mafic, metaluminous to peraluminous, calc-alkalic (alkali-lime index${\fallingdotseq}$ 57) and I-type (magnetite-series) based on the chemical data_ And they appear to have been fractionated at the order of Geodo granodiorite, Quartz monzonite porphyry and Imog granite. In terms of mineralogy, geochemistry and K/Ar biotite age, a rock suite of monzodiorite, quartz monzodiorite and quartz monzonite-granodiorite in the Geodo stock was fractionally differentiated from a magmatic body from its margin to inward.

• Journal of the Korean Society of Fisheries and Ocean Technology
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• v.47 no.3
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• pp.203-213
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• 2011

The age and growth of flathead grey mullet, Mugil cephalus, were studied using samples collected from the coastal water of Yeosu from September 2009 to August 2010. Spawning season estimated from the gonadosometic index (GSI) was from November to January. A method for increasing the readability of the otolith was described and criteria for the interpretation of otolith was provided. The annual ring was formed in September once a year. Annual ring in otolith for flathead grey mullet is validated for fish aged 1-8 using the marginal increment analysis. Using the sectioned otolith, between reader precision was 84%. Also, Within-reader agreement for sectioned otolith age readings was higher (reader 1=84%, reader 2=87%). The relationship between fork length and total weight was TW=$0.022FL^{2.818}$. The estimated von Bertalanffy growth parameters for the flathead grey mullet were $L_{\infty}$=67.97cm K=0.164/year and $t_o$=-0.81year.

• Journal of the Korean Society of Safety
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• v.27 no.1
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• pp.26-31
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• 2012

Wood-plastic composites represents a growing class of materials used by the residential construction industry and furniture industry. In this study, the effect of flame retardants on the flammability and mechanical properties of wood flour-high density polyethylene(HDPE) composites were studied. we were manufactured wood flour-HDPE composites by modular intermeshing co-rotating twin screw extruder with L/D ratio of 42. The flame retardant properties were used limiting oxygen index(LOI) and mechanical properties were measured by universal testing machine(UTM). The Morphological analysis of composites were analyzed by Scanning electron microscope(SEM). It was found that Ammonium polyphosphate can effectively reduce the flammability of the wood flour-HDPE composites. Marginal reduction in the mechanical properties of the composites was found with addition of flame retardants. SEM images showed that the coupling agent improved wood flour-HDPE interfacial bonding.

• Journal of Nutrition and Health
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• v.27 no.10
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• pp.1058-1069
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• 1994

This study was performed to study the effects of dietary factors on breast and cervical cancer incidence in female Koreans. The subjects were 60 breast and 109 cervical cancer patients recruited from five general hospitals in Seoul. Food intake, anthropometric measurement, and blood compositions were studied through personal interview and using medical records, from August 1991 to September 1992. Body weight, body mass index, triceps skinfold thickness and body muscle mass were at upper limit of normal value, which suggest that these patients had a tendency of overweight. The levels of hemoglobin and hematocrit of the patients were below the normal values. The values of serum protein, albumin, and calcium were in the normal range but close to the lower bound. Therefore the nutritional status assessed by blood composition seems to be marginal. The results of diet history showed that most of the nutrient intake of the subjects met with RDA. The fat intake were 22.9-36.9g/day which supplies about 15-16% of total calories. The results of this study do not agree with those reports of western societies which showed the positive correlation between calorie and fat intake and the incidence of breast and cervical cancer. Even through the calories and fat intake of the subjects were not high, it was higher than national average, especially in breast cancer patients. From this study, dietary factors does not seem to be a major risk factor in cancer incidence in Korea. However, the tendency of the increasing consumption of fat could be a contributing risk factor together with overweight.