• Korean Journal of Food Science and Technology
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• v.46 no.5
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• pp.575-580
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• 2014

Model gel food samples of yanggaeng (Y) were prepared for the elderly with various gelling agents, including agar (AG), low acyl gellan (GL), ${\kappa}$-carrageenan (CA), locust bean gum (LB), glucomannan (GM), and xanthan gum (XA) in different combinations as follows (in 1:1 ratio): LB+CA, GM+XA, and GM+CA. The quality characteristics of the different combinations were compared. The results revealed that water loss was highest for Y-GL, whereas there was no significant difference among the other samples. Y-GL showed the highest values for lightness in color, whereas Y-AG showed the lowest. Regarding textural properties, Y-LB+CA had the highest hardness value, whereas Y-GL had the lowest; the hardness of Y was related to the cross-section of the added gel. Finally, Y-GM+XA exhibited the highest score in overall acceptability in the sensory test by elderly, indicating that the preferable texture by elderly is slightly chewy, but not adhesive.

• Entomological Research
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• v.48 no.6
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• pp.533-539
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• 2018

The RNA interference (RNAi) has been considered as an important genetic tool and applied to develop a new living modified (LM) crop trait which is an improvement of nutrient quality or pest management. The RNAi of DvSnf7 has been used for resistance to LM maize and the Western Corn Rootworm which is a major agricultural pest for the US Corn Belt. Most of the environmental risk assessments (ERA) of double strand RNA (dsRNA) have been performed using in vitro transcript products, and not in vivo expressed product. A large amount of dsRNA was required for the acute toxicity assay of water fleas. Therefore development of massive dsRNA purification techniques is critical. Daphnia, a freshwater microcrustacean, is a model organism for studying cellular and molecular mechanism involved in life history traits and ecotoxicology. In this study, we established the massive dsRNA purification method using Escherichia coli and implemented acute toxicity assays to Daphnia magna. As a result, the present RNase A and DNase I, dsRNA was efficiently purified without any special techniques or equipment. Even though purified dsRNA existed during the acute toxicity test, lethality or abnormal behavior were not observed in D. magna. These results indicated that GFP and DvSnf7 dsRNA were not significantly affected to D. magna due to their lack of sequence matching in its genome. The purification method of dsRNA and the acute toxicity assay of water fleas using purified dsRNA would be suitable for the toxicological studies of LMOs to aquatic non-target organisms.

• Journal of Biosystems Engineering
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• v.33 no.4
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• pp.260-268
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• 2008

Optical diffuse reflectance sensing has potential for rapid and reliable on-site estimation of soil properties. For good results, proper calibration to measured soil properties is required. One issue is whether it is necessary to develop calibrations using samples from the specific area or areas (e.g., field, soil series) in which the sensor will be applied, or whether a general "factory" calibration is sufficient. A further question is if specific calibration is required, how many sample points are needed. In this study, these issues were addressed using data from 42 paddy fields representing 14 distinct soil series accounting for 74% of the total Korean paddy field area. Partial least squares (PLS) regression was used to develop calibrations between soil properties and reflectance spectra. Model evaluation was based on coefficient of determination ($R^2$) root mean square error of prediction (RMSEP), and RPD, the ratio of standard deviation to RMSEP. When sample data from a soil series were included in the calibration stage (full information calibration), RPD values of prediction models were increased by 0.03 to 3.32, compared with results from calibration models not including data from the test soil series (calibration without site-specific information). Higher $R^2$ values were also obtained in most cases. Including some samples from the test soil series (hybrid calibration) generally increased RPD rapidly up to a certain number of sample points. A large portion of the potential improvement could be obtained by adding about 8 to 22 points, depending on the soil properties to be estimated, where the numbers were 10 to 18 for pH, 18-22 for EC, and 8 to 22 for total C. These results provide guidance on sampling and calibration requirements for NIR soil property estimation.

• Journal of Korean Society of Coastal and Ocean Engineers
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• v.13 no.2
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• pp.89-99
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• 2001

In the present paper, Helmholtz resonator, which is widely used as a sound-amplification device, is applied to the development of seawater-exchanging breakwater. The incident waves can induce a large response in the resonator when incident wave frequency is close to one of natural modes of the resonator. Largely amplified potential energy due to the resonance supplies clean seawater into the harbor side throughout the channel. Flow supplied by the resonator circulates the seawater of harbor and helps to improve water quality. Within the framework of linear potential theory, matched asymptotic expansion method is employed to analyze the wave responses in a resonator. The semi-circular shape of the resonator has been chosen as an analytic model for mathematical simplicity. The wave responses of both single and arrays of Helmholtz resonator are investi¬gated. To validate an analytic solution, model test is conducted at 2-dimensional wave tanle Wave hcights in the resonator and velocity at the channel are measured for the state of valve-on and valve-off.

• Journal of the Korean Society of Environmental Restoration Technology
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• v.1 no.1
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• pp.28-44
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• 1998

This study was conducted to suggest the ecological restoration strategies for the disturbed landscapes by theoretical study. Especially, it is aimed to suggest three objectives for restoration by using native plants ; (1) prevention or reduction of wind and water erosion, (2) provision of food and cover for variety of animal species, (3) improvement of the visual or aesthetic quality of disturbed sites. The main results were summarized as follows. 1. Cooperation between restoration ecologists and restoration practitioners is needed to delineate a scientific approach to restoration ; (1) Being aware of published literature that describes similar work and/or establish general principles. (2) Preparedness to carry out proper experiments to test ideas. (3) Preparedness to monitor fundamental parameters in a restoration scheme. (4) Providing information about the behavior of species. (5) Publish results. 2. There are three models of succession in theories of plant succession. The tolerance and facilitation models were recommended to ecological restoration. The inhibition model applies in most secondary succession, but the actual species which are introduced first may inhibit the germination and growth of slower-growing species, or they may prevent the growth of other species whose propagules arrive later. 3. The objectives of erosion control, wildlife habitat provision, and visual quality improvement are not mutually exclusive. However, many revegetation practices in the past have emphasized one of these aspects at the expense of the others. 4. A native plant community can be the model of ecological restoration. By stylization/abstraction of native plant community, trying to learn the most essential characteristics of community types - environmental factors ; dominant, prevalent, and "visual essence" species composition - in order to use such information in restoration. 5. After developing mass/spaces plan, match plant communities to the mass/space plan. In utilizing community grouping, there needs aesthetic ability to understand design elements. 6. Several hydrophytes such as Pennisetum saccharifluous, Themeda triandra, Cirsium pendulum show relatively good germination rates. In case of mesophytes and xerophytes, Arundinella hina, Artemisia princeps, Oenothera odorata and legumes seem to have quick-germinating abilities at barren sites. Pinus thunbergii, Rhus chinensis, Evodia daniellii, Alnus firma and Albizzia julibrissin can be considered as "late succession" woody plants because they show low germinating rates and slow growing habitat. 7. The seeds used for restoration should be collected within a certain radius of where it will be planted. Consideration in genetic issues in the collection and use of germplasm can increase the odds for successful restoration efforts. 8. The useful model in the "drift" pattern occurs so abundantly in naturally evolving landscapes. As one species diminishes in density, a second or third species are increased. Thus, dynamic interactions between species are created. Careful using of "drift phenomenon" in planting was recommended. 9. Virtually no stand of vegetation today is immune from the introduction and/or spreading of exotic species. Therefore, the perpetuation of a restored sites requires conscious monitoring and management. Thus, management would be the most important process in ecological restoration. 10. In order to keep the sites "natural", alternative management strategies would be applied in management ; Atenative management strategies are decelerating successional process, accelerating successional processes or modifying species composition. As management tools, mechanical, chemical, biological or environmental factor manipulation, e.g., fire could be used.

• Korean Journal of Environmental Biology
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• v.33 no.1
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• pp.45-52
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• 2015

Acute toxicity tests for 5 organic solvents were conducted using Euglena agilis carter (E. agilis), a Korean domestic organism. Organic solvents decreased the growth rate of E. agilis in a dose dependent manner. The toxicity to E. agilis was increased in the order of chloroform>acetone${\geq}$ethanol${\geq}$methanol>DMSO based on $EC_{50}$ values from growth test. Organic solvents also induced cell motility and morphological changes of E. agilis. Especially significant effects on the cell swimming velocity, motility, and compactness were observed for chloroform at the concentration of $EC_{50}$ calculated from 96 hr growth test. Overall, toxic responses of E. agilis to test substances are comparable to or more sensitive than D. magna, M. macrocopa and V. fischeri. Our study demonstrates that E. agilis can be a putative ecotoxicity test model organism to assess domestic water quality. Results obtained from this study can be applied to establish the standard test guidelines for ecotoxicity test using E. agilis.

• Journal of Physiology & Pathology in Korean Medicine
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• v.24 no.6
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• pp.1034-1041
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• 2010

The oriental medicine Jangwonhwan, which is a boiled extract of 12 medicinal herbs/mushroom, has been prescribed for patients with cognitive dysfunction and it is originally from the Korean medical text, DonguiBogam(amnesia chapter). Recently, a modified recipe of Jangwonhwan (LMK02-Jangwonhwan) consisting of seven medicinal plants/mushroom, was shown to reduce ${\beta}$-amyloid deposition in the brain of Tg-APPswe/PS1dE9 mouse model of Alzheimer disease. The toxicity of LMK02 was investigated in SD rats by oral repeated adminstration for 4 weeks and we tried to determine test does for 13 weeks repeated study. Quality control of tablet form of LMK02 was established by estimating indicative components, Ginsenoside Rg3 of Red Ginseng and Decursin of Angelicagigas Nakai. The toxicity of LMK02 was investigated in 6 weeks old specific pathogen free (SPF) Sprageu-Dawley rats by oral administration. Each test group were consist of 5 male and 5 female and they received doses of 500, 1,000 and 2,000 mg/kg/day of test substance for 4 weeks. The clinical signs, death rate, body weight, food consumption, ophthalmic examination, urinalysis, hematological and serum biochemistry, organ weight and pathological changes were examined and compared with those of control group. Urinalysis : We observed increase of PRO(p<0.01), SG(p<0.01) in female rats of 1,000 mg/kg/day and 2,000 mg/kg/day(p<0.01). Also, we observed increase of pH and KET in female rats of 1,000 mg/kg/day(p<0.05) and of 2,000 mg/kg/day(p<0.01). WBC in female rats in 1,000 mg/kg/day and 2,000 mg/kg/day were on increase. Hematological test : We observed increase of MCV in male rats of 250 mg/kg/day. (p<0.05) Serum biochemistry test : We found increase of CHO in female rats of 2,000 mg/kg/day(p<0.05). During the experimental period, there were no animals dead or moribund. There were no treatment related changes of general symptom, food and water consumption, organ weight and autopsy According to the results of 4-week repeated dose range finding study, the highest dose was established as 1000 mg/kg for 13-week repeated dose toxicity study and we determined to put 2 more groups by common ratio two.

• Korean Journal of Environmental Biology
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• v.41 no.2
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• pp.109-125
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• 2023

This study was conducted to select target fish species as baseline research for accumulation analysis of major hazardous chemicals entering the aquatic ecosystem in Korea and to analyze the impact on fish community. The test bed was selected from a sewage treatment plant, which could directly confirm the impact of the inflow of harmful chemicals, and the Geum River estuary where harmful chemicals introduced into the water system were concentrated. A multivariable metric model was developed to select target candidate fish species for hazardous chemical analysis. Details consisted of seven metrics: (1) commercially useful metric, (2) top-carnivorous species metric, (3) pollution fish indicator metric, (4) tolerance fish metric, (5) common abundant metric, (6) sampling availability (collectability) metric, and (7) widely distributed fish metric. Based on seven metric models for candidate fish species, eight species were selected as target candidates. The co-occurring dominant fish with target candidates was tolerant (50%), indicating that the highest abundance of tolerant species could be used as a water pollution indicator. A multi-metric fish-based model analysis for aquatic ecosystem health evaluation showed that the ecosystem health was diagnosed as "bad conditions". Physicochemical water quality variables also influenced fish feeding and tolerance guild in the testbed. Eight water quality parameters appeared high at the T1 site, indicating a large impact of discharging water from the sewage treatment plant. T2 site showed massive algal bloom, with chlorophyll concentration about 15 times higher compared to the reference site.

• Journal of the Korea Concrete Institute
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• v.22 no.3
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• pp.409-417
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• 2010

This paper discusses a series of experiments including material improvement in order to ensure quality of grouting for the post-tensioned structure. In prestressed concrete, grouting refers to the construction procedure of filling empty space of duct enclosing with strands using cementitious material, To date, adequate quality control of the grouting has not been established in Korea because the relationship between the grouting and durability of post-tensioned structure is not well-recognized. The Korean standard does not consider the important material characteristic, wick effect, which is caused by strands in the ducts and current standard testing method unlikely quantify reasonable material segregation. As a result, the grout material, which meets the current material standards, may exhibit excessive bleeding water or shrinkage during construction. In this study, international codes and standards related to grouting were surveyed. The ratio of constituents and novel admixtures were suggested to meet equivalently with these standards. Performance of this enhanced grout was compared to common domestic grout using the international standard testing method. A series of mock-up specimens considering geometry of PC beam was constructed and grout flow pattern was observed as the grout was injected. It was observed that the grouting performance was highly influenced by material properties and filling characteristic can be varied depending on geometry of ducts.

• Journal of the Korea Concrete Institute
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• v.24 no.2
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• pp.137-145
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• 2012

Strength model for blasted furnace slag mortar blended with sodium was investigated in this study. The main parameters of AAS (alkali activated slag) mortar were dosage of alkali activator, water to binder ratio (W/B), and aggregate to binder ratio (A/B). For evaluating the property related to the dosage of alkali activator, sodium carbonate ($Na_2CO_3$) of 4~8% was added to 4% dosage of sodium hydroxide (NaOH). W/B and A/B was varied 0.45~0.60 and 2.05~2.85, respectively. An alkali quality coefficient combining the amounts of main compositions of source materials and sodium oxide ($Na_2O$) in sodium hydroxide and sodium carbonate is proposed to assess the compressive strength of alkali activated mortars. Test results clearly showed that the compressive strength development of alkali-activated mortars were significantly dependent on the proposed alkali quality coefficient. Compressive strength development of AAS mortars were also estimated using the formula specified in the previous study, which was calibrated using the collected database. Predictions from the simplified equations showed good agreements with the test results.