• Korean Journal of Ichthyology
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• v.35 no.2
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• pp.91-100
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• 2023

The early life history of Silurus microdorsalis living in Jahocheon Stream was studied by observing egg and morphological development. Live fish were captured in June 2018, then reared in a circulating filtration system under a 14L : 10D photoperiod with a water temperature of 18℃. To artificially induce spawning, females were injected with 0.5 mL of Ovaprim (Syndel, Nanaimo, BC, Canada) per kg of body weight, and males were injected with 10,000 IU/kg body weight of human chorionic gonadotropin. Approximately 15 h later, eggs were artificially inseminated by the dry method. Mature eggs were light pale yellow, which separated them from immature eggs. Fertilized eggs were 2.16±0.06 mm (n=8) in diameter and fully hatched at 181 h after fertilization. The fertilization rate was 63.1±2.2%, and 10.0±3.7% of the embryos were malformed at 18℃. The rates of development were 181 h at 18℃, 109 h at 21℃, and 76 h at 24℃. The larval size immediately after hatching was 4.64±0.22 mm (n=8), and the larvae displayed negative phototaxis at 1 day after hatching. The total larval length on 7 days after hatching was 12.47±0.53 mm, with 25~30 basal anal fin rays and 14~16 basal caudal fin rays observed. The total larval length was 14.13±0.51 mm on 9 days after hatching, and approximately 90% of the black endoplasmic reticulum was deposited on the head and body. The dorsal fin had formed, and a single basal body was observed. On 15 days after hatching, the total larval length was 16.69±0.31 mm; the number of basal caudal fin rays (18 poles) was an integer because 2 dorsal fin basal rays and 60~63 anal fin basal rays were observed. The total larval length was 28.96±1.10 mm on 50 days after hatching; the numbers of caudal fins (n=18), dorsal fins (n=3), pectoral fins (n=11), and anal fin basal rays (n=67~73) were integers.

• Journal of Food Hygiene and Safety
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• v.38 no.3
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• pp.99-111
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• 2023

The purpose of this study was to provide basic data for setting more detailed standards for baby food and to provide food information that can be used in real-world settings. We purchased 80 snacks and 40 drinks for infants and toddlers from supermarkets and online markets and analyzed tar color, artificial sweeteners, mycotoxins, and nutritional components (e.g., sucrose, sodium, and calcium). Fortunately, it was confirmed that both tar color and sodium saccharin, which do not have detection criteria for labeled foods for infants and toddlers, were not detected. However, acesulfame potassium was detected at 0.07 g/kg in one snack sample. As for myxotoxins, aflatoxin (B1, B2, G1, and G2) and ochratoxin A were not detected. Fumonisin B1, fumonisin B2, and zearalenone were detected in the ranges of 9.78-78.94 ㎍/kg, 5.58-11.73 ㎍/kg, and 2.96-8.83 ㎍/kg, respectively, but only in snacks. Sucrose was detected in 65 of the snacks (0.02-40.94 g/net weight [g]) and in 24 of the drinks (0.12-27.60 g/net weight [g]). Minerals were detected in most of the samples, and in four snacks, the zinc content per net exceeded the tolerable upper intake level for infants. Sixteen snacks exceeded the food standards for sodium content for infants and toddlers, but none of them were labeled as food for infants and toddlers in the product manufacturing report, such that the corresponding standards could not be applied. Therefore, it seems necessary to establish institutional improvements, such as strengthening labeling standards, so that the currently enforced standards can be appropriately applied, and establishing standards for labeled foods for infants and toddlers.

• Journal of Food Hygiene and Safety
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• v.38 no.3
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• pp.123-130
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• 2023

Salmonella spp. are prevalent foodborne pathogens that are infective at relatively low concentrations, thus posing a serious health threat, especially to young children and the elderly. In several countries, the management and regulation of Salmonella spp. in food, including seafood, adhere to a negative detection standard. The risk of infection is particularly high when seafood is consumed raw, which underscores the importance of timely detection of pathogenic microorganisms, such as Salmonella. Accordingly, this study aimed to develop a combined pre-treatment and detection method that includes pre-culture and DNA extraction in order to detect five species of Salmonella at concentrations below 10 CFU/mL in seafood. The effectiveness of the proposed method was assessed in terms of the composition of the enrichment (pre-culture) medium, minimum incubation time, and minimum cell concentration for pathogen detection. Furthermore, a practical DNA extraction method capable of effectively handling high salt conditions was tested and found to be successful. Through polymerase chain reaction, Salmonella spp. Were detected and positively identified in shellfish samples at cell concentrations below 10 CFU/g. Thus, the proposed method, combining sample pre-treatment and cell culture with DNA extraction, was shown to be an effective strategy for detecting low cellular concentrations of harmful bacteria. The proposed methodology is suitable as an economical and practical in situ pre-treatment for effective detection of Salmonella spp. in seafood.

• Journal of the Korean Society of Food Culture
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• v.21 no.6
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• pp.644-652
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• 2006

This study was investigated the utilization of pomegranate(P) as coagulants for 새려 manufacture, the quality characteristics and shelf-life on tofu made by P1(fruit juice of pomegranate 1%) and P2(fruit juice of pomegranate 2%) and P3(fruit juice of pomegranate 3%) and P4(fruit juice of pomegranate 4%) and P5(fruit juice of pomegranate 5%) were investigated and compared to G.D.L(C). And also, total microbe and tatal acid of the tofu were determined during storage at $0^{\circ}C^$. The results are summarized as follow P3(493.3g/500ml) compared to C(485g/500ml) showed the highest yield. Turbidity of tofu was increased as the proportion of pomegranate was increased, while pH of tofu was increased as the proportion of pomegranate was decreased. $L^{\ast}^{\ast}^{\ast}$ value of C tofu was highest, $a^{\ast}^{\ast}^{\ast}$ value of tofu was increased as the proportion of pomegranate was increased and $b^{\ast}^{\ast}^{\ast}$ value of C tofu was higher than those of other tofus. The hardness of tofu coagulated with pomegranate showed higher than that of coagulated G.D.L. The cohesiveness of P4, P5 showed higher than C tofu, but those of other tofus showed lower than C tofu. The springiness of tofu showed in the order of P4>P5>P3>P2>P1, gumminess of P5 tofu was highest. The Brittleness of tofu was increased as the proportion of pomegranate increased. The pH value of tofu coagulated with pomegranate increased during storage at $0^{\circ}C^$. During the storage period of tofu, pH and total acid showed a maximum change in C tofu. Generally the total plate counts of bacteria of all tofu increased during storage at $0^{\circ}C^$, and those of tofu with added pomegranate were shown to be lower than C tofu. The results of S.E.M(scanning electron microscopes), the lower hardness showed the more soft and the smaller particle, The particle of C tofu was small and uniformity but the size of P4, P5 tofu showed coarse. In the sensory evaluation of all tofu, sleekness, nutty, chewiness and smoothness, appearance and overall quality was the highest in C tofu. In the sensory evaluation of tofus coagulated with pomegranate. overall quality was the highest in P2.

• Journal of the Korean Society of Food Culture
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• v.21 no.3
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• pp.297-302
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• 2006

This study has examined the physicochemical properties of the Pleurotus eryngii, including their proximate components, amount mineral content, total dietary fiber, total sugar, reducing sugar and free sugar. Additionally, it measured the P. egii ethanol extracts and the total amounts of polyphenol compounds as well as its electron donating ability (EDA) of the substance fraction (SF). The P. eryngii powder's moisture content was 9.0% and each of the other element content such as carbohydrate, crude protein, crude ash and crude fat was found to be 63.06%, 20.70%, 5.20% and 2.0% respectively. Potassium (K) was shown to be the greatest inorganic content and manganese (Mn) was the lowest. Furthermore fructose, galactose, glucose lactose and maltose free sugar content was found in this order. 387 mg% of the total amounts of polyphenol was found in the P. eryngii whole body ethanol extract, 158 mg% in the stipe extract, 593 mg% in the pileus extract and 607 mg% in the substance fraction (SF). Electron donating ability (EDA) was highest at 91.12% in the whole body extract and lowest at 62.90% in the stipe extract. Additionally, the EDA for substance fraction (SF) 0.02%-0.1% was found to be 57.78-77.33%, which was lower than the 0.02%-tocopherol (93.92%) and BHT (96.72%). From these results, it can be assumed that P. eryngii offers superior antioxidative effects with its high content of fiber, inorganic materials and total amounts of polyphenol as well as high electron donating ability (EDA), thereby making it ideal for use in functional foods and industrial materials.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.26 no.6C
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• pp.395-406
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• 2006

Drilled shafts are a common foundation solution for large concentrated loads. Such piles are generally constructed by drilling through softer soils into rock and the section of the shaft which is drilled through rock contributes most of the load bearing capacity. Drilled shafts derive their bearing capacity from both shaft and base resistance components. The length and diameter of the rock socket must be sufficient to carry the loads imposed on the pile safely without excessive settlements. The base resistance component can contribute significantly to the ultimate capacity of the pile. However, the shaft resistance is typically mobilized at considerably smaller pile movements than that of the base. In addition, the base response can be adversely affected by any debris that is left in the bottom of the socket. The reliability of base response therefore depends on the use of a construction and inspection technique which leaves the socket free of debris. This may be difficult and costly to achieve, particularly in deep sockets, which are often drilled under water or drilling slurry. As a consequence of these factors, shaft resistance generally dominates pile performance at working loads. The efforts to improve the prediction of drilled shaft performance are therefore primarily concerned with the complex mechanisms of shaft resistance development. The shaft resistance only is concerned in this study. The nature of the interface between the concrete pile shaft and the surrounding rock is critically important to the performance of the pile, and is heavily influenced by the construction practices. In this study, the influences of asperity characteristics such as the heights and angles, the strength characteristics and elastic constants of surrounding rock masses and the depth and length of rock socket, et. al. on the shaft resistance of drilled shafts are investigated from elasto-plastic analyses( FLAC). Through the parametric studies, among the parameters, the vertical stress on the top layer of socket, the height of asperity and cohesion and poison's ratio of rock masses are major influence factors on the unit peak shaft resistance.

• Journal of the Korean Society of Food Culture
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• v.23 no.2
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• pp.222-227
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• 2008

This study examined the chemical composition of lotus root and functionally evaluated a fermented lotus root drink. Electron-donating ability using DPPH along with nitrite-scavenging ability were used to compare the antioxidative activities of unfermented and fermented lotus root drinks. The electron-donating abilities of the unfermented lotus root drink (1%) and fermented lotusroot drink (1%) were 22.55% and 23.88%, respectively. At pH 6.0, the nitrite-scavenging abilities of the unfermented lotus root drink and the fermented lotus root drink (100%) were 27.64% and 40.3%, respectively, and their scavenging ability increased in a dose-dependent manner at all pH values. In order to study the anti-obesity effects of the two drinks, male Sprague-Dawley rats were divided into four groups (A: basal diet, B: high fat diet, C: high fat diet+unfermented lotus root drink, D: high fat diet+fermented lotus root drink). Net weight gains were not significantly different among the four groups. Plasma total cholesterol concentrations significantly decreased in the groups receiving the unfermented and fermented lotus root drinks. Also, plasma total lipid and triglyceride contents were lower in the groups receiving the unfermented and fermented lotus root drinks as compared to the high fat diet group; however, the differences among the three groups were not significant.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.30 no.1B
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• pp.41-51
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• 2010

In this study, runoff simulation was carried out in the area of Bisan 7-dong, Seo-gu, Daegu as drainage basin and the effects of the installation of underground storage facilities were analyzed during heavy rainfall. SWMM model was used for the runoff and pipe network analysis on Typhoon Maemi, 2003. 2-D inundation analysis model based on diffusion wave was employed for inundation analysis and to verify computed inundation areas with observed inundation trace map. The simulation results agree with observed in terms of inundation area and depth. Also, the effects of flood damage mitigation were analyzed through the overflow discharge and 2-D inundation analysis, depending upon whether the underground storage facility is installed or not. When the underground storage facility ($W:120m{\times}L:180m{\times}H:1.7m$) is installed, volume of overflow could be reduced by 72% and flooding area could be reduced by 40.1%. When the underground storage facility ($W:120m{\times}L:180 m{\times}H:2.0m$) is installed, volume of overflow could be reduced by 84.8% and flooding area could be reduced by 50.6%. When the underground storage facility ($W:120m{\times}L:180m{\times}H:2.2m$) is installed, volume of overflow could be reduced by 94% and flooding area could be reduced by 91.2%. There is no overflow of manhole, when the height of storage facility is 2.5 m. It is expected that the study results presented through quantitative analysis on the effects of underground facilities can be used as base data for socially and economically effective installation of underground facilities to prevent flood damage.

• Journal of Korean Tunnelling and Underground Space Association
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• v.11 no.1
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• pp.57-70
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• 2009

Considerable advance has been made on research on effect of steel pipe Umbrella Arch Method (UAM) and mechanical reinforcement mechanism through numerical analyses and experiments. Due to long analysis time of three-dimensional analysis and its complexity, un-quantitative two-dimensional analysis is dominantly used in the design and application, where equivalent material properties of UAM reinforced area and ground are used, For this reason, development of reasonable, theoretical, quantitative and easy to use design and analysis method is required. In this study, both field UAM tests and laboratory tests were performed in the residual soil to highly weathered rock; field tests to observe the range of reinforcement, and laboratory tests to investigate the change of material properties between prior to and after UAM reinforcement. It has been observed that the increase in material property of neighboring ground is negligible, and that only stiffness of steel pipe and cement column formed inside the steel pipe and the gap between steel pipe and borehole contributes to ground reinforcement. Based on these results and concept of Convergence Confinement Method (CCM), two dimensional axisymmetric analyses have been performed to obtain the longitudinal displacement profile (LDP) corresponding to arching effect of tunnel face, UAM effect and effect of supports. In addition, modified load distribution method in two dimensional plane-strain analysis has been suggested, in which effect of UAM is transformed to internal pressure and modified load distribution ratios are suggested. Comparison between the modified method and conventional method shows that larger displacement occur in the conventional method than that in the modified method although it may be different depending on ground condition, depth and size of tunnel, types of steel pipe and initial stress state. Consequently, it can be concluded that the effect of UAM as a beam in a longitudinal direction is not considered properly in the conventional method.

• Journal of the Korean Society of Marine Environment & Safety
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• v.29 no.4
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• pp.297-306
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• 2023

Saemangeum Lake is the largest artificial lake in Korea. The continuous deterioration of lake water quality necessitates the introduction of novel water quality management strategies. Therefore, this study aims to identify the spatiotemporal water quality characteristics of Saemangeum Lake using data from the National Water Quality Measurement Network and provide basic information for water quality management. In the water quality parameters of Saemangeum Lake, water temperature and total phosphorous content were correlated, and salt, total nitrogen content, pH, and chemical oxygen demand were significantly correlated. Other parameters showed a low correlation. The spatial principal component analysis of Saemangeum Lake showed the characteristics of its four zones. The mid-to-downstream section of the river affected by freshwater inflow showed a high nutrient salt concentration, and the deep-water section of the drainage gate and the lake affected by seawater showed a high salt concentration. Two types of water qualities were observed in the intermediate water area where river water and outer sea water were mixed: waters with relatively low salt and high chemical oxygen demand, and waters with relatively low salt and high pH concentration. In the principal component analysis by time, the water quality was divided into four groups based on the observation month. Group I occurred during May and June in late spring and early summer, Group II was in early spring (March-April) and late autumn (November-December), Group III was in winter (January-February), and Group IV was in summer (July-October) during high temperatures. The water quality characteristics of Saemangeum Lake were found to be affected by the inflow of the upper Mangyeong and Dongjin rivers, and the seawater through the Garuk and Shinshi gates installed in the Saemangeum Embankment. In order to achieve the target water quality of Saemangeum Lake, it is necessary to establish water quality management measures for Saemangeum Lake along with pollution source management measures in the upper basin.