• Restorative Dentistry and Endodontics
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• v.47 no.3
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• pp.29.1-29.10
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• 2022

Objectives: This study aimed to investigate the anti-erosive/abrasive effect of resin infiltration of previous deproteinized dentin. Materials and Methods: Dentin slabs were randomly assigned to 3 groups (n = 15): Control (no deproteinization; no resin infiltrant applied), RI (no deproteinization; resin infiltrant applied), and DRI (deproteinization; resin infiltrant applied). After undergoing the assigned treatment, all slabs were subjected to an in vitro cycling model for 5 days. The specimens were immersed in citric acid (0.05 M, pH = 3.75; 60 seconds; 3 times/day) and brushed (150 strokes). Between the challenges, the specimens were exposed to a remineralizing solution (60 minutes). The morphological alterations were analyzed by mechanical profilometry (㎛) and scanning electron microscopy (SEM). Data were submitted to one-way analysis of variance (ANOVA) and Tukey tests (p < 0.05). Results: Control and RI groups presented mineral wear and did not significantly differ from each other (p = 0.063). DRI maintained a protective layer preserving the dentin (p < 0.001). After erosive/abrasive cycles, it was observed that in group RI, only 25% of the slabs partially evidenced the presence of the infiltrating, while, in the DRI group, 80% of the slabs presented the treated surface entirely covered by a resin-component layer protecting the dentin surface as observed in SEM images. Conclusions: The removal of the organic content allows the resin infiltrant to efficiently protect the dentin surface against erosive/abrasive lesions.

• Proceedings of the Korean Society of Crop Science Conference
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• 2022.10a
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• pp.322-322
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• 2022

Hay and haylage as forage are increasing in preference for cattle feed. Triticale (X Triticosecale Wittmack) is growing up as a forage crop due to its high production and feed value in South Korea. It is difficult to determine the harvesting stage of triticale for producing hay or haylage with the highest forage value and quality because feed and nutritional value by growth stages of triticale were not known in South Korea yet. In this study, we analyzed forage values, pH, and contents of organic acid, to confirm feed value and quality by growth stages of triticale. The triticale 'Joseong' was sown in the spring of 2022. The sample was prepared in 5 stages: seedling stage, booting stage, heading stage, 10 days after heading, and 20 days after heading. The triticale was dried under 10% and to about 50% moisture for hay and haylage respectively, and then both triticales were fermented anaerobically at room temperature for 40 days. The pH value in all hay and haylage became lower as the triticale was grown up, although the pH value of all triticale hays and haylages ranged between 7.05-5.68. The content of lactic acid in all triticale hays was almost meaningless. The contents in the haylage of the seedling stage were the highest (2.39%) among the haylages, even though those of 20 days after the heading stage (1.67%) were the lowest, which showed a similar tendency with pH value. Conclusionally, the results implied that the feed value and quality of triticale haylage were affected by harvesting time but not hay.

• Food Science and Preservation
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• v.30 no.4
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• pp.617-629
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• 2023

Reactive oxygen species are the byproducts of metabolic processes in the body, However, excessive amount may cause side effects such as cancer. Therefore, to reduce the production of these species, but their long-term administration at high doses may induce side effects. Hence, natural materials with antioxidant activities are attracting attention. Two of these natural materials are soybean sprouts and Hovenia dulcis Thunb. fruits, but few studies have evaluated the effects of their combination. Thus, we prepared a soybean sprout extract containing 1.5% H. dulcis Thunb. fruit concentrate (BHM) to develop a functional food material derived from natural products and then confirmed its physicochemical properties and physiological activity. Among the organic acids detected in BHM, malic acid exhibited the highest content of 1,451.03 ppm, and the main free sugars were glucose (645.48 ppm) and fructose (738.11 ppm). Taurine was the most abundant free amino acid at a concentration of 11.95 ppm, followed by those of arginine (10.97 ppm) and glutamic acid (10.16 ppm). Analyses of the mineral components revealed large amounts of Zn and Fe in BHM, and the respective total polyphenol and flavonoid contents in BHM were 957.16 and 601.93 ppm. The DPPH radical and H₂O₂ scavenging activities and reducing power indicated excellent antioxidant efficacy compared to the positive controls. Furthermore, blood alcohol and acetaldehyde concentrations were measured to confirm the hangover-relieving effects of BHM, with both significantly decreased (p<0.05). BHM displays potential for development as a functional food, and the results of this study may be used as basic data in further research.

• The Korean Journal of Food And Nutrition
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• v.37 no.4
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• pp.189-196
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• 2024

To develop farm-made high effective vinegar, this study prepared apple vinegar using four kinds of acetic acid bacteria isolated from a natural fermentation liquid of 'Cheongsoo' grapes and analyzed vinegar samples fermented 93% apple juice and 7% alcohols at 30℃ for 20 days. To accomplish this, quality characteristics such as pH, total acidity, reducing sugar, organic acid, color, total polyphenol contents, and antioxidant activity contents were determined. The pH decreased while total acidity of all samples gradually increased during fermentation period. The vinegar with AP 21 strain tended to increase the total acidity quicker than other stains. Reduced sugar content remained high until the last fermentation day. Furthermore, reduced sugar contents of all vinegars increased as fermentation progressed by decomposing sucrose present in apples. When physiological activities were compared, apple vinegars fermented with AP 21 and 30 strains had higher total polyphenol and flavonoid contents than other samples. However, there was no significant difference in antioxidant activity between samples. These results indicate that strain 21 is the most suitable starter as acetic acid bacteria for producing farm-made vinegar.

• Korean Journal of Agricultural Science
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• v.49 no.4
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• pp.1055-1066
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• 2022

This study investigated quality characteristics of chicken stock with added plum extract (PE) and green tea powder (GP) stock during storage. Plum extract (0, 0.5, 1, 3%) and green tea powder (0, 0.5, 1, 3%) were added at three levels. Chicken stock was stored at room temperature for 14 days. The pH of the chicken stock decreased significantly as the content of PE and GP increased (p < 0.05). The group with 3% plum extract added showed significantly lower pH values (p < 0.05). Total numbers of microorganisms (TMC) showed significant differences according to the storage period (p < 0.05), where the groups with PE and GP added showed lower TMC values than the control group, This indicates that PE and GP could inhibit the growth of microorganisms. The addition of 3% PE or GP decreased lipid oxidation (TBARS) and protein deterioration (VBN) values. In sensory test, the results showed that adding PE or GP has a positive effect on storage characteristics of chicken stock. The addition of PE rather than GP is effective not only in improving sensory evaluation, but also in minimizing changes in quality by suppressing lipid oxidation and protein deterioration during storage. In conclusion, 3% PE addition was found to be the most optimal supplementation choice for increasing the storability of chicken stock.

• Korean Journal of Soil Science and Fertilizer
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• v.7 no.1
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• pp.29-34
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• 1974

On a newly reclamed acidic Song-jong soil (soil of a member of fine loamy, mesic family of Hapludults) an experiment was carried out to find out the proper measure of the improvement of soil fertility with soybean as test crop. Results are summarized as follow: 1. Application of compost (1 ton/10a), lime (lime requirement)and fused phosphate (equivalent to 5% of the phosphate fixation coefficient)resulted in the increase of soybean yield by 93.3% over the check plot (N: 6kg/10a, $P_2O_5$: 9kg/10a, $K_2O$: 6kg/10a). The application of fused phosphate at the level of 5% of phosphate fixation coefficient N (6kg/10a) and K(6kg/10a) brought the yield increase by 62.7% over the check plot. However, although the pH of the soil was adjusted to 7.0 by liming, the application of lime with moderate dose of phosphate ($P_2O_5$: 9kg/10a) did not increase the yield of soybean significantly. And the application of fused phosphate at the level of 5% of phosphate fixation coefficient increased the available soil P from 14 ppm to around 100 ppm as tested after harvest. 2. Application of compost (1 ton/10a) increased the organic matter content of soil by 0.8% when tested after harvest. While, the application of rice straw (0.5 ton/10a) did not alter the soil organic matter content. The CEC of the soil tested after havest found incereased significantly by the addition of lime and compost. 3. Plant analysis revealed that the $K_2O/Ca+Mg$ is better correlated with the yield than the absolute concentration of $K_2O$ in plant tissue. Between the concentration of $P_2O_5$ in plant tissue and the yield of soybean, a typical C-curve relationship was observed, indicating that in this particular soil, phosphate was the primary growth liming factor.

• Korean Journal of Soil Science and Fertilizer
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• v.7 no.1
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• pp.5-16
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• 1974

This study was carried out to judge the use of hilly land and Development. Data collected from detailed soil survey were analyzed for the study. The results obtained were as follows. 1. Only a few crops were cultivated on the residual soils and old alluvium soils, and the yield of these crops was low. The farmars in the area are pool. 2. The cultivated land in the study area comprises 58.4%. Soil conservation practices in this area were very poor. The 37.2% forest land in the area contained only a few trees and was gradually deteriorating because lack of management 3. The twelve soil series were investigated. There were various soils such as reddish brown and dark brown loam derived from residium, yellowish red and brown clay derived from old alluvium, and dark brown and grayish brown loam derived from narrow local valley alluvium. 4. The soil reaction of the old alluvial soils (pH 4.7 to 4.8) was more acid than that of the residual soil (5.0 to 5.2). The organic matter content of the old alluvial soils (3.3 to 3.6%) however, was higher than that of the residual soils (2.6 to 2.8%). The cation exchange capacity was 8 to 16 me/100g soil and was closely related to the content of organic matter, clay and silt. 5. The hill land was classified into sixteen land suitability groups by the soil characteristics. 6. There were significant differencies between the present land use and the recommended land use after the soil survey 7. The forest land was mainly converted to grass, nut tree, orchards and mulberry lands.

• Korean Chemical Engineering Research
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• v.50 no.4
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• pp.672-677
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• 2012

Lipids in microalgal biomass were recovered by using pyrolysis method. The pyrolysis experiments of two Chlorella sp. KR-1 samples, which have triglyceride contents of 10.8% and 36.5%, respectively were carried out at $600^{\circ}C$ to investigate the effects of lipid contents in the cells on the reaction characteristics. The conversion and liquid yield of the lipid-rich sample were higher than those of the lipid-lean sample since its carbon to hydrogen ratio was low. There were low molecular weight organic acids, ketones, aldehydes and alcohols in the liquid products from both KR-1 samples, but the pyrolysis oil of the lipid-rich sample was abundant in free fatty acids, particularly palmitic acid, oleic acid and stearic acid while the content of nitrogen containing organic compounds was low. The microalgal pyrolysis oil had two layers composed of the light hydrophobic fraction and the heavy hydrophilic fraction. The light fraction might be originated from triglycerides and the heavy fraction might be from carbohydrates and proteins. In the light fraction of the liquid products, there were considerable linear alkanes such as pentadecane and heptadecane as well as free fatty acids, implying that deoxygenation reaction including decarboxylation was occurred during the pyrolysis. The yield of the liquid products from the pyrolysis of the KR-1 sample having triglyceride content of 36.5% was 56.9% and the light fraction in the liquid products was 68.2%. Also more than 80% of the light fraction was free fatty acids and pure hydrocarbons, thus showing that most triglycerides could be extracted in the form of suitable raw materials for biofuels.

• Journal of the Korean Institute of Landscape Architecture
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• v.43 no.3
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• pp.77-91
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• 2015

This study aims to suggest adequate soil management through the analysis of physicochemical properties of soil in the planting grounds of Incheon International Airport, which was constructed on a massive land reclamation site. Study areas were 5 sites at the international business complex, the passenger terminal, the airport support complex, the free trade zone, and the access road. Soil profile analysis showed that 9 plots out of the 27 plots were hardpan and heterospere within 80cm from the soil surface. The earth laid on the ground was categorized as gravel based soil(4 plots), dredged soil from the sea bottom and mixed reclamation materials(2 plots), clay with poor permeability(3 plots) and waste construction material(1 plot). Average soil hardness was $11.5kg/cm^2$ and soil textures were sandy soil, sandy loam and loamy sand. Average soil pH was 6.7 and average organic matter content was 0.7%. Electrical conductivity was 0.0dS/m and exchangeable cation concentrations were $Ca^{2+}$ 3.4cmol/kg, $Mg^{2+}$ 1.5cmol/kg, $K^+$ 0.3cmol/kg and $Na^+$ 1.0cmol/kg. Average cation exchange capacity was 11.0cmol/kg. Although average figures in Solum mostly meet the landscape design criteria, properties of each soil layer showed various values sometimes over the limit. Base saturations were $Ca^{2+}$ 29.9%, $Mg^{2+}$ 13.3% and $K^+$ 3.7% for lower soil, $Ca^{2+}$ 33.3%, $Mg^{2+}$ 17.0% and $K^+$ 2.7% for mid-soil and $Ca^{2+}$ 32.6%, $Mg^{2+}$ 12.2% and $K^+$ 1.9% for upper soil. Exchangeable sodium percentages were 16.4% for lower soil, 7.5% for mid-soil and 4.7% upper soil. Sodium adsorption rates were 0.8 for lower soil, 0.3 for mid-soil and 0.2 for upper soil. Factors affecting to the vegetation growth were heterogeneity and poorness of solum, disturbance of dredged soils, high soil hardness including hardpan in the subsurface soil layer and shallow effective soil depth, high soil acidity, imbalance of base contents, low organic matter content and low available phosphate levels in the soil.

• Journal of the Korea Organic Resources Recycling Association
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• v.16 no.2
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• pp.47-56
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• 2008

The objective of this research is to evaluate the optimum recycling methods for the sewage sludge cakes at different microwave power-settings and for different periods of time. The dehydrated sewage sludge cakes used in this study was obtained from N wastewater treatment plan in the P City. The beginning drying processes were carried out in a microwave oven with 2,450 MHz frequency and power ranges of 1kW to 4 kW. The continuous conveyer drying system was also operated with 2,450 MHz frequency and power setting, ranging from of 1 kW to 6 kW. Initial moisture content of the sewage cake is 78~80%, and the moisture content decreased rapidly up to 0.2~2(wt%) within short periods due to breaking the cell walls. This study is also conducted to evaluate the characteristics of sewage sludge cakes with respect to important physical parameters effect on the thermal kinetics for evaporation water in the sludge which are operation times, moisture contents, drying rates, input amounts, flow rates and calorific values. It takes 60 minutes and 120 minutes to reach the critical moisture contents with power setting of 4 kW for 3kg/min and 6kg/min of the flow rates respectively. It takes 120 minutes and 110 minutes to reach the critical moisture contents with flow rates of 2.5 cm/min and sludge input of 6kg/min for the power settings of 4 kW and 6 kW respectively. The most effective value of the power for drying the sludge is 4 kW. Operation with 6kg/min and 4kW on 2cm of the sludge thickness can be effectively and inexpensively to reach the critical moisture contents, when you compare 2cm of the sludge thickness with 1cm and 3cm of the sludge thickness.