• The Korean Journal of Pesticide Science
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• v.10 no.3
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• pp.189-195
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• 2006

The purpose of the current study was to develop a standard method to assess the ecological effect of pesticides using the representative Korean freshwater cladocerans. The indigenous cladocerans, Daphnia obtusa, Daphnia sp., Moina macrocopa, Simocephalus vetulus and Daphnia magna formally endorsed by the major international organizations were tested to select optimal culture media in laboratory condition. All of the Korean water flea tested showed good growth and fecundity in the moderately hard water ($CaCO_3$ ranged 80 to 100 mg $L^{-1}$) and soft water ($CaCO_3$ ranged 40 to 48 mg $L^{-1}$). However, considering that the total hardness of fresh water collected from 5 rivers ranged from 60.2 to 127.2 mg $L^{-1}$ ($CaCO_3$) and Ca deficiency could be a major determinant of species success and community structure among crustacean zooplankton, the present study suggests that the optimal water hardness for growing Daphnia sp., Daphnia obtusa, Moina macrocopa and Simocephalus vetulus is $80{\sim}100$ mg $L^{-1}$ of $CaCO_3$.

• Journal of Korean Society of Environmental Engineers
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• v.39 no.1
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• pp.1-8
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• 2017

Drinking water deficiency is prevalent in developing countries due to contamination of surface and ground water, difficulties of water treatment, and lack of water infrastructures. 'Rainwater For Drinking (RFD)' projects are emerging as one of the effective solutions globally since RFD systems provide safe drinking water from rainwater. In RFD projects, perception of local residents toward RFD project is essential as local residents must manage their RFD systems on their own after the project finishes. This research performed survey and interview to 209 local residents, who use RFD systems, and analyzed their general perception, expected effects and feared factors toward RFD projects. Through the research, it was shown that the most of the local residents have positive perception towards RFD projects' effectiveness (41.9%) and are willing to participate (58.9%). The top three expected effect factors of the RFD projects were 'supply of safe water source', 'vitalization of local community', and 'expansion of RFD system'. The top three feared factors were 'quality of rainwater', 'technical factors of RFD system', and 'maintenance of RFD system'. The research findings indicate that development of simple water quality measuring device and education of the local residents about RFD system is necessary for better maintenance of the RFD system after the project finishes.

• Journal of Navigation and Port Research
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• v.37 no.4
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• pp.419-427
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• 2013

The purpose of this study was to analyze the perceptions to improvement directions of related regulations for water leisure activation. In order to accomplish such study purpose, the study utilized a survey methodology with 205 water leisure participants and 117 water leisure business employees. In addition, this study attempted to review the license and education system, registration and inspection system and business organizations from the advanced countries such as US, British, Australia and Japan. Accordingly, following findings were derived from current study. First, the problems of current license system included difficulty of operating the system and deficiency of operating organizations, and the improvement directions included expansion of education organizations and differentiation of education based on levels. Second, the improvement directions of registration and inspection included simplification of registration procedures and expansion of registration and inspection organizations. Third, difficulties perceived by business employees included complexity of entry and departure, complexity of registrating water leisure business and insufficiency of supporting business policies. In conclusion, water leisure related regulations including Water Leisure Safety Act need to be reformed continuously to reflect changing demands and needs from participants and business sectors.

• Journal of Applied Biological Chemistry
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• v.59 no.3
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• pp.227-231
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• 2016

Deep sea water (DSW) is located 100 to 500 m below the sea surface. DSW is widely used in various fields, and is an important source of minerals that can be used to treat mineral deficiency. In the present study, the oral toxicity of DSW-mineral extracts was determined using single-dose and 14-day repeated dose oral toxicity tests in ICR mice. For the single-dose oral toxicity tests, mineral extracts of magnesium (Mg) and calcium (Ca) at doses of 0, 6, 270, 810, and 1,350 mg/kg, respectively, were orally administered to mice once at the beginning of the experiment, and the mice were observed for 14 days. For the 14-day repeated dose oral toxicity tests, Mg and Ca mineral extracts at doses of 0, 3, 135, 405, 675 mg/kg, respectively, were orally administered to mice daily, and the mice were observed for 14 days. Various tests were performed including visual observation; analysis of relative organ weight, food intake, and organ weight; biochemical analysis, and histopathology. The results indicated that mortality and changes in appearance were not observed among differentially administered groups of male and female ICR mice during the experimental period. Differences in body weight gain, food intake, organ weight, and histopathology parameters were not significant between the control and mineral-administered groups. Some results of the biochemical analyses were significantly different, but showed no specific tendencies. Overall, no evidence of toxicity was observed from the oral administration of DSW extracts of Ca and Mg in ICR mice.

• Nutrition Research and Practice
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• v.14 no.2
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• pp.143-151
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• 2020

BACKGROUND/OBJECTIVES: The nutrition of the elderly depends on various factors. Oral health, especially oral dryness, can be an important risk factor. In this study, we attempted to determine whether dry mouth is associated with compromised nutrient intakes. SUBJECTS/METHODS: A total of 120 participants aged 65-86 yrs (mean age: 69 ± 1 y) were included in this study. Demographic and health-related characteristics, living status, meals, number of medications, medical conditions, chewing ability, and quality of life, the Oral Health Impact Profile (the OHIP-14) were assessed. We performed one day 24-hr recall assessment for nutrient analyses. The differences of the means between the dry-mouth and non-dry-mouth groups were analyzed. Elderly subjects with xerostomia-induced dry mouth were classified as those who reported at least one dryness symptom on a questionnaire. RESULTS: A significant difference in population distribution was observed among the elderly who took medications for hypertension, diabetes and osteoporosis and was significantly higher in the dry-mouth group (70.2%) than in the non-dry-mouth group (44.4%) (P = 0.005). Compared with the non-dry-mouth group (50.8%), a significantly higher proportion (73.7%) of participants in the dry-mouth group took multiple medicines (≥ 4 medications) (P = 0.019). The intakes of vegetable fat, vitamin E, folate and water in the dry-mouth group were lower than in the non-dry-mouth group. The intakes of fluoride and ω-3 fatty acids were significantly lower in the dry-mouth group than in the non-dry-mouth group. CONCLUSION: The participants in the dry-mouth group exhibited low nutrient and water intakes. It is recommended that the elderly with dry mouth should drink sufficient water and receive targeted and specific nutritional guidance to prevent malnutrition.

• Journal of Oriental Neuropsychiatry
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• v.20 no.2
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• pp.1-17
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• 2009

Objectives : Alzheimer's disease(AD) is the most common form of dementia, which is characterized by progressive deterioration of memory and higher cortical functions that ultimately results in total degradation of intellectual and mental activities. Nokyongdaebo-tang(Lurongdabutang) has been usually used for the treatment for the deficiency syndrome dementia and amnesia. This experiment was designed to investigate the effect of the Nokyongdaebo-tang(Lurongdabutang) hot water extract on pathological AD model. Methods : The effects of the Nokyongdaebo-tang(Lurongdabutang) hot water extract on cultured spinal cord cells induced by ${\beta}$-amyloid were investigated. The effects of the Nokyongdaebo-tan(Lurongdabutang) hot water extract on the memory deficit mice induced by scopolamine were investigated. Results : 1. ${\beta}$-amyloid treatment on cultured spinal cord cells increased both GFAP-staining intensity of astrocytes and caspase 3 immunoreactivity on cultured cells. Then, Nokyongdaebo-tang(Lurongdabutang) treatment reduced the labeling intensity for both GFAP and caspase 3 proteins in culture cells. 2. Scopolamine treatment into mice increased levels of GFAP-positive astrocytes and caspase 3-labeled cells of the hippocampal subfields dentate hilar region, CA3 and CA1 area. In vivo administration of Nokyongdaebo-tang(Lurongdabutang) attenuated labeling intensity for those two proteins in the same hippocampal areas. Similar effects were observed by the treatment of galanthamine, an inhibitor of acetylcholinesterase. Conclusions : This experiment shows that the Nokyongdaebo-tang(Lurongdabutang) may play a protective role in damaged neural tissues. Since neuronal damage seen in degenerative brains such as AD are largely unknown, the current data may provide possible insight into therapeutic strategies for AD treatments. Nokyongdaebo-tang(Lurongdabutang) might be effective for the prevention and treatment of AD.

• Journal of Applied Biological Chemistry
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• v.42 no.3
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• pp.140-145
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• 1999

Livestock manure is generally beneficial to soil and crop production when appropriate amount is applied, but excessive application may be detrimental to soil and water environments. A proper protocol of livestock waste treatment is required to manage the quality of soil and water. A trickling filter system using rice straw media was employed to treat piggery wastewater from small-scaled livestock farms as an alternative to the currently available methods. Batches of piggery wastewater were treated with this system, and the byproducts of rice straw media and trickling filtrate were applied to the soil with cultivating rye (Secale cereale L.). Objective of this research was to characterize these byproducts for the sustainable soil amendments and rye production. Both the treated straw medium and filtrate were proven to be effective organic fertilizers for rye plant development, with the enhanced but balanced absorption of nutrients. The synergistic effects of filtrate in addition to straw application did not show, but the filtrate appeared to lead to a higher water content of the plant. No specific nutrient deficiency or toxicity symptom was shown due to the salts derived from the byproducts applied. Chemical parameters of the soil quality were significantly improved with the application of straw medium either with or without the filtrate. Judging from parameters relating to the salt accumulations, such as sodium adsorption ratio (SAR), electrical conductivity (EC), exchangeable sodium percentage (ESP), potassium adsorption ratio (KAR), and residual P concentrations, the byproducts from piggery wastewater exhibited no detrimental effects on soil quality within the ranges of treatments used. In addition to the effectiveness of the rice straw trickling filter system for the small-scaled swine farms, both rice straw medium and filtrate could be recycled for the sustainable soil amendment and plant nutrition.

• The Korean Journal of Ecology
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• v.18 no.1
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• pp.43-54
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• 1995

Effects of environmental factors of N, P, pH, moisture, temperature and oxygen on growth and nitrogen fixation activity of kummerowia striate (Thunb.) Schindler seedling, bearing symbiotic root nodules, were quantitatively analyzed during the growing period. The specific nitrogenase activity (ARA) of nodules showed the maximum value of 187 μmol C₂H₄g fr wt-1 h-1 6 weeks after seeds were germinated. The total nitrogenase activities per plant attained as 1.56, 0.85, 0.09 and 4.0, 1.11, 0.04 μmol C₂H₄hr-1, respectively for the treatments of 1, 3 and 5 mM NO₃￣and NH₄＋ on the 60th day. While the plant grown in N-free media for 20 days after treatments of 5 mM NH₄+for 40 days resulted in 30 mg fr wt of nodule formation and exhibited the relative activities of 152％ and 162％ for total and specific ARA in comparison with those of control plant grown with N-free for 60 days. Total biomass and ARA was by 70％ and 86％ lower in N and P deficiency, respectively. The N and P deficient plot showed 70％ and 86％ decreases of total biomass and ARA in comparison with those of control. The plant grown with N-free for 20 days after pretreatment with N and P free media for 40 days showed the relative values of 77％, 118％ and 150％, respectively for nodule biomass, total and specific ARA in comparison with those of control. The treatment with acid or alkali gradients resulted in significant decreases of nodule biomass and ARA. The optimum temperature and pO₂for ARA were 30°C and 40 kPa, respectively. Two peaks of diurnal variation appeared at 11:00 and 23:00 o'clocks by the continuous light condition. The plants with water stress by temporary wilting point rsulted in 95~97％ inhibition for nodule respiration, transpiration and specific ARA. Transpiration and ARA ware recovered to 88％ and 38％ of those of water unstressed plants, respectively, 6 hours after the plants were rewatered from water stressed condition.

• Korean Journal of Community Nutrition
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• v.13 no.3
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• pp.405-417
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• 2008

The purpose of the study was to investigate the sanitation management status and implementation barriers of the HACCP system. A survey was conducted based on 760 schools through e-mail after having gone through phone interviews to dieticians in Seoul, Gyeonggi and Incheon areas from December 2006 to March 2007. The following statistics were drawn out from the 459 surveys out of the 760, thus giving a response rate of 60.4% (N = 459). The statistical data analysis was completed using the SPSS program. 92.6% of the respondents operated sanitary education once a month and 67.1 % used internet as their sanitary educational source. 50.5% of the pre-preparation rooms were not divided and 78.0% of kitchen floors were always kept wet. Only 15.7% of the respondents used heat and cold insulators and 73.2% of drinking water was natural or purified water. 60.3% of food trays were electronically sterilized and 70.2% of spoons and chopsticks were sterilized by boiling water. The main cause of food-borne diseases was the lack of facilities and equipment (33.1%). Also, the deficiency of facilities and equipment (4.07 points) acted as an implementation barrier of the HACCP system. Compared to Gyeonggi or Incheon area results, Seoul's facilities and equipment (p < 0.001) and implementing barriers of the HACCP system (p < 0.001) results came out relatively high. After the analysis of the implementation barriers of the HACCP system, 91.7% of school principals said it was difficult to apply the HACCP system due to lack of financial support. In consideration to the school foodservice support, solutions for the facilities of school foodservice and a systematic sanitary education of the HACCP system must be made for the employees and everyone else who are related.

• Computers and Concrete
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• v.24 no.3
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• pp.193-206
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• 2019

Although concrete is the most widely used construction material, its deficiency in shrinkage and low tensile resistance is undeniable. However, the aforementioned defects can be partially modified by addition of fibers. On the other hand, possibility of adding waste materials in concrete has provided a new ground for use of recycled concrete aggregates in the construction industry. In this study, a constant combination of recyclable coarse and fine concrete aggregates was used to replace the corresponding aggregates at 50% substitution percentage. Moreover, in order to investigate the effects of fibers on mechanical and durability properties of recycled aggregate concrete, the amounts of 0.5%, 1%, and 1.5% steel fibers (ST) and 0.05%, 0.1% and 0.15% polypropylene (PP) fibers by volumes were used individually and in hybrid forms. Compressive strength, tensile strength, flexural strength, ultrasonic pulse velocity (UPV), water absorption, toughness, elastic modulus and shrinkage of samples were investigated. The results of mechanical properties showed that PP fibers reduced the compressive strength while positive impact of steel fibers was evident both in single and hybrid forms. Tensile and flexural strength of samples were improved and the energy absorption of samples containing fibers increased substantially before and after crack presence. Growth in toughness especially in hybrid fiber-reinforced specimens retarded the propagation of cracks. Modulus of elasticity was decreased by the addition of PP fibers while the contrary trend was observed with the addition of steel fibers. PP fibers decreased the ultrasonic pulse velocity slightly and had undesirable effect on water absorption. However, steel fiber caused negligible decline in UPV and a small impact on water absorption. Steel fibers reduce the drying shrinkage by up to 35% when was applied solely. Using fibers also resulted in increasing the ductility of samples in failure. In addition, mechanical properties changes were also evaluated by statistical analysis of MATLAB software and smoothing spline interpolation on compressive, flexural, and indirect tensile strength. Using shell interpolation, the optimization process in areas without laboratory results led to determining optimal theoretical points in a two-parameter system including steel fibers and polypropylene.