• The Journal of Korean Academy of Prosthodontics
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• v.61 no.2
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• pp.101-112
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• 2023

Purpose. This retrospective study was to investigate the survival and complication rates of posterior single implant according to the implant diameters, lengths and position. Materials and methods. Patients who had been restored single implant prosthesis in the posterior area by the three prosthodontists in the department of prosthodontics, Daejeon dental hospital of Wonkwang university, in the period from February 2014 to May 2018 were selected for the study. A total of 505 patients with 697 implants were observed. The survival and complications of implants were investigated using electronic medical records and radiographs. Fixture diameters, lengths, position, patient's sex and age were assessed as possible factor affecting the survival and complications of implants. Results. 3-year cumulative survival rates of posterior single implants were 98.5% and 5-year cumulative survival rates were 94.4%. 5-year cumulative survival rates were higher in implants with diameter > 4.0 mm (97.0%) than implants with diameter ≤ 4.0 mm (89.5%), and in females (98.8%) than males (92.4%). There were statistically significant differences (P < .05). The mechanical complication rate was 20.1% and the biological complication rate was 4.7%. Complications occurred in order of abutment screw loosening (7.5%), decementation (6.3%), proximal contact loss (3.7%) and so on. Abutment screw loosening occurred more frequently in the lower molar region (10.5%), in males (9.5%) than females (5.1%), and in patients aged < 65 years (9.4%) than patients aged ≥ 65 years (5.1%). There were statistically significant differences (P < .05). Conclusion. The 5-year cumulative survival rates were higher in implants with diameter > 4.0 mm than implants with diameter ≤ 4.0 mm and in females than males. Abutment screw loosening which was the most commonly occurring complication occurred more frequently in the lower molar region, in males than females, and in patients aged < 65 years than patients aged ≥ 65 years. There were statistically significant differences.

• Korean Journal of Environmental Biology
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• v.39 no.4
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• pp.526-535
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• 2021

Spatial sampling design plays an important role in GIS-based modeling studies because it increases modeling efficiency while reducing the cost of sampling. In the field of agricultural systems, research demand for high-resolution spatial databased modeling to predict and evaluate climate change impacts is growing rapidly. Accordingly, the need and importance of spatial sampling design are increasing. The purpose of this study was to design spatial sampling of paddy fields (11,386 grids with 1 km spatial resolution) in Korea for use in agricultural spatial modeling. A stratified random sampling design was developed and applied in 2030s, 2050s, and 2080s under two RCP scenarios of 4.5 and 8.5. Twenty-five weather and four soil characteristics were used as stratification variables. Stratification and sample allocation were optimized to ensure minimum sample size under given precision constraints for 16 target variables such as crop yield, greenhouse gas emission, and pest distribution. Precision and accuracy of the sampling were evaluated through sampling simulations based on coefficient of variation (CV) and relative bias, respectively. As a result, the paddy field could be optimized in the range of 5 to 21 strata and 46 to 69 samples. Evaluation results showed that target variables were within precision constraints (CV<0.05 except for crop yield) with low bias values (below 3%). These results can contribute to reducing sampling cost and computation time while having high predictive power. It is expected to be widely used as a representative sample grid in various agriculture spatial modeling studies.

• Journal of the Korean Geotechnical Society
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• v.25 no.4
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• pp.91-103
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• 2009

Slope failure depends upon the climatic features related to related rainfall, structural geology and geomorphological features as well as the variation of the mechanical behaviors of soil constituting a slope. In this paper, among many variables, effects of soil layer thickness on the slope failure process, and variations of matric suction and volumetric water content were observed. When the soil layer is relatively thick, the descending wetting front decreases matric suction and the observed matric suction reaches to "0" value. When the wetting front reaches to the impermeable boundary, the bottom surface of steel soil box, ascending wetting front was observed. This observation can be postulated to be the effects of various sizes of pores. When macro size pores exist, the capillary effects can be reduced and infilling of pore will be limited. The partially filled pores would be filled with water during the ascending of the wetting front, which bounces from the impermeable boundary. This assumption has been assured from the observation of variation of the volumetric water contents at different depth. When the soil layer is thick (thickness = 20 cm), for granular material, erosion is a cause triggering the slope failure. It has been found that the initiation of erosion occurs when the top soil is fully saturated. Meanwhile, when the soil layer is shallow (thickness = 10 cm), slope slides as en mass. The slope failure for this condition occurs when the wetting front reaches to the interface between the soil layer and steel soil box. As the wetting front approaches to the bottom of soil layer, reduction of shear resistance along the boundary and increase of the unit weight due to the infiltration occur and these produce complex effects on the slope failure processes.

• Journal of Bio-Environment Control
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• v.32 no.2
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• pp.157-164
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• 2023

Codonopsis lanceolata (S. et Z.) Trautv. is mainly cultivated in Korea and China as a medicinal crop. C. lanceolata is difficult to produce plug seedlings in the summer, because C. lanceolata has a low germination rate and is vulnerable to high temperatures. Cold treatment is effective in breaking dormancy of seeds and increasing the germination rate. Shading cultivation can control the solar irradiance received by plants and reduce the damage by high temperatures and strong light. This study was conducted to examine the appropriate cold treatment period for the improving germination of C. lanceolata, and shading level during the summer seedling period. Cold treatment experiments were conducted for 0 (control), 1, 2, 3, and 4 weeks at 4℃ before sowing. In the shading experiment, C. lanceolata was grown for 45 days with 0 (non-treatment), 45, 75% shading levels. Cold treatment for one week significantly improved the germination energy. The plant height, leaf area, and fresh and dry weights of C. lanceolata seedlings were significantly increased under the 45% shading level. Total root length, root surface area, and the number of root tips were significantly higher in shading treatment (45 and 75%) than in non-treatment. The C. lanceolata seedling's compactness and Dickson's quality index were the highest at 45% shading level. Therefore, these results recommended sowing C. lanceolata after cold treatment for one week at 4℃, and 45% shading level could stably culture C. lanceolata plug seedlings during the high temperature period.

• Journal of The Korean Society of Grassland and Forage Science
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• v.43 no.1
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• pp.28-34
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• 2023

This experiment was carried out to determine effects of seed rate of native grasses, called native summer forage crops (NSFC), on their growth characteristics and yields in no-tillage paddy fields in central provinces. NSFC cultivation was performed according to the agricultural guidelines of the Rural Development Administration (RDA) during 2020 to 2022. Echinochloa crusgalli 'Jeju native', Setaria viridis 'Korean native type', Digitaria sanguinalis 'Korean native type') were sown by various seed rate in the experimental field (3m × 4m plot) of Department of Animal Resources Development, Seonghwan-eup, Cheonan, Korea in late-May or early-June for 3 years and harvested in middle-September. Dry matter yields (DMY) in Echinochloa crusgalli and Setaria viridis increased as increasing seed rate. DMY in 40 kg ha^-1 of Echinochloa crusgalli was the highest and DMY in 60 kg ha^-1 of Setaria viridis was the highest. However, All treatments of Digitaria sanguinalis showed similar DMY. Yields of NSFC were the order of Echinochloa crusgalli (9,681~11,092 kg ha^-1) > Digitaria sanguinalis (8,311~9,023 kg ha^-1) >etaria viridis (3,145~4,749 kg ha^-1). The contents of crude protein in NSFC were the order of Digitaria sanguinalis > Echinochloa crusgalli > Setaria viridis. The contents of ADF and NDF in NSFC were the order of Echinochloa crusgalli > Digitaria sanguinalis > Setaria viridis. As shown in above results, we suggest that introduction of NSFC is one of the most important skills in order to stably increase yields of forage crops for utilization of the double cropping system in no-tillage paddy fields.

• Journal of The Korean Society of Grassland and Forage Science
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• v.43 no.1
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• pp.35-41
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• 2023

This experiment was carried out to examine double cropping system using Italian ryegrass (IRG) 'Kowinearly', whole crop rice 'Yeongwoo' and barnyard millet 'Jeju native' during the Oct. 2020 to Oct. 2022. Three kinds of forage crops were cultivated at paddy field in Livestock Institute, Jeollanamdo Agricultural Research and Extension Services, Jeollanamdo, South Korea. Whole crop rice (WCR) was sown in late May and barnyard millet (BM) sown early June each year after harvesting IRG. We examined dry matter yield and feed value of forage crops depending on harvest time of forage crops during the experimental period. The plant height in heading stage of IRG ranged from 108 to 112cm and dry matter yield ranged from 6,783 to 11,530 kg ha^-1. The crude protein (CP) of IRG ranged from 6.0 to 8.44%, acid detergent fiber (ADF) ranged from 55.6 to 60.2% and neutral detergent fiber (NDF) ranged from 32.58 to 36.7%, The dry matter yield of WCR increased as the harvest stage was delayed (14,310 kg ha^-1 in milk, 16,167 kg ha^-1 in yellow ripen, and 18,891 kg ha^-1 in mature). Similar to results of dry matter yield of WCR, dry matter yield of BM increased as the harvest stage was delayed (11,194 kg ha^-1 in late heading. and 14,308 kg ha^-1 in mature), However nutrient content of WCR and BM showed a decreasing trend. As shown in above results, the productivity of WCR after harvesting IRG was shown to be high at paddy field in the southern region. However, BM also was appeared to have potential as summer forage crops.

• Journal of The Korean Society of Grassland and Forage Science
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• v.42 no.1
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• pp.10-16
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• 2022

This study was conducted to examine the dry matter yield and weed control of alfalfa according to postemergence herbicides treatment during spring seeding alfalfa. The seeding time of alfalfa was April 21, 2021, the seeding amount was 20 kg/ha, and the seeding method was by 20 cm wide. The alfalfa harvest was carried out at the early bloom stage (10% of flowering), and the harvest date was June 29, 2021. The test treatments were non herbicide (NH), hand weeding (HW), herbicide 1 (Trifluralin, H1), herbicide 2 (S-metolachlor, H2), herbicide 3 (Alachlor, H3), and herbicide 4 (Pendimethalin, H4). Alfalfa plant height was significantly highest in H2 (62.1±1.4 cm) followed by H3 (61.7±1.6 cm), HW (58.5±1.0 cm), H1 (57.2±1.3 cm), H4 (56.1±1.3 cm), and NH (54.1±1.2 cm) (p<0.05). Based on HW, H2 and H3 were high and H1 and H4 were short, but NH was significantly shorter than HW and H1~H4 (p<0.05). The dry matter yield of alfalfa in NH, HW, H1, H2, H3, and H4 were 717.2±94.2, 2,613.8±254.1, 1,667.8±94.1, 2,498.3±120.2, 2,435.0±118.3, and 1,793.7±354.3 kg/ha. HW is the highest among them (p<0.05). The feed composition of alfalfa was 22~24% of the dry matter yield, and the CP content were significantly higher in NH (23.6 %) (p<0.05). The NH had higher (p<0.05) NDF and ADF, but RFV was lower (p<0.05). The weed plant height was NH 98.0±3.3cm, HW 73.3±1.7 cm, H1 91.9±1.5 cm, H2 53.3±5.8 cm, H3 81.4±3.5 cm and H4 96.6±2.2 cm, and H2 was significantly smallest in the group (p<0.05). The weed dry matter yield was NH 4,770.4±232.5 kg/ha, HW 316.3±91.9 kg/ha, H1 2,353.4±173.7 kg/ha, H2 114.5±10.2 kg/ha, H3 752.7±440.6 kg/ha and H4 2,220.6±775.6 kg/ha. The weed control value was HW 94.1%, H1 53.5%, H2 98.2%, H3 84.9%, H4 48.7%, the weed value of H2 is similar to weed control value of HW. Considering the above results, postemergence herbicide treatment controlled weeds by more than 50% compared with no treatment, and among herbicides, H2 (S-metolachlor) was found to be on a similar level to hand weeding.

• Journal of The Korean Society of Grassland and Forage Science
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• v.42 no.1
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• pp.17-25
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• 2022

This study was carried out the estimation on consumption patterns and consciousness of domestic forage for improvement of the quality of domestic forage. Although the cultivated area in South Korea of forage has increased significantly compared to the past, the self-sufficiency rate of domestic forage has increased to around 80% since 2010. Also, livestock farmers prefer to use import forage than domestic due to convenience of use. In Korean beef farms, the ratio of import to domestic forage was higher in domestic forage (import forage 3 : domestic forage 7). In the method of securing domestic forage, purchase of forage (55.6%) was higher than self-cultivation of forage (44.4%). The ratio of use by bailing type was shown in the order of rice staw rice straw (50.5%), domestic hay (15%), imported hay (12.5%), and total mixed ratio (10.7%). The preference of forage was in the order of amount of foreign matter, moisture content, price, feed value in Korean native cattle farm. The result of satisfaction with domestic and import forage showed that the satisfaction of domestic forage price was higher than import forage, while the moisture content and foreign matter of forage were lower than import forage. In addition, in the results of the satisfaction and importance of domestic roughage compared to imported roughage, satisfaction with imported roughage was generally high in all items except for price. As a result, in order to improve the satisfaction of domestic forage in Korean native cattle farm, it is necessary to minimize foreign matter in forage and increase hay production for moisture content uniform in forage.

• Korean Journal of Food Science and Technology
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• v.54 no.1
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• pp.43-51
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• 2022

Regulation of the hair follicle cycle in association with dermal papilla cells is one of the most interesting targets for promoting hair regrowth. In this study, we examined whether steam-dried Betula platyphylla extracts (BPE) promote hair growth by upregulating in vitro and in vivo responses of dermal papilla cells. The data showed that BPE3 contained high amounts of phenolic compounds with higher antioxidant effects and increased hair growth-related genes, including fibroblast growth factor7 and Wnt7b, in dermal papilla cells. Notably, BPE3 effectively enhanced the formation of hair follicles by increasing FGF7, Wnt7b, and vascular endothelial growth factor in C57BL/6N dorsal skins. Additionally, BPE3 significantly decreased the expression of inflammatory repertoires, inducible nitric oxide synthase, interleukin-6, and cyclooxygenase 2. Several small molecules, such as betulin and unsaturated fatty acids, support the pharmacological activity of BPE3. In conclusion, BPE3 effectively promoted hair growth by activating dermal papilla cells and enhancing hair follicle cycles by attenuating the inflammatory environment in the scalp.

• Korean Journal of Ecology and Environment
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• v.55 no.1
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• pp.60-75
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• 2022

The Bayesian algorithm model is a model algorithm that calculates probabilities based on input data and is mainly used for complex disasters, water quality management, the ecological structure between living things or living-non-living factors. In this study, we analyzed the main factors affected Korean Estuary Trophic Diatom Index (KETDI) change based on the Bayesian network analysis using the diatom community and physicochemical factors in the domestic estuarine aquatic ecosystem. For Bayesian analysis, estuarine diatom habitat data and estuarine aquatic diatom health (2008~2019) data were used. Data were classified into habitat, physical, chemical, and biological factors. Each data was input to the Bayesian network model (GeNIE model) and performed estuary aquatic network analysis along with the nationwide and each coast. From 2008 to 2019, a total of 625 taxa of diatoms were identified, consisting of 2 orders, 5 suborders, 18 families, 141 genera, 595 species, 29 varieties, and 1 species. Nitzschia inconspicua had the highest cumulative cell density, followed by Nitzschia palea, Pseudostaurosira elliptica and Achnanthidium minutissimum. As a result of analyzing the ecological network of diatom health assessment in the estuary ecosystem using the Bayesian network model, the biological factor was the most sensitive factor influencing the health assessment score was. In contrast, the habitat and physicochemical factors had relatively low sensitivity. The most sensitive taxa of diatoms to the assessment of estuarine aquatic health were Nitzschia inconspicua, N. fonticola, Achnanthes convergens, and Pseudostaurosira elliptica. In addition, the ratio of industrial area and cattle shed near the habitat was sensitively linked to the health assessment. The major taxa sensitive to diatom health evaluation differed according to coast. Bayesian network analysis was useful to identify major variables including diatom taxa affecting aquatic health even in complex ecological structures such as estuary ecosystems. In addition, it is possible to identify the restoration target accurately when restoring the consequently damaged estuary aquatic ecosystem.