• Economic and Environmental Geology
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• v.49 no.6
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• pp.445-458
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• 2016

Most of water curtain cultivation (WCC) area in Korea has been inveterately suffering from the gradual draw-down of groundwater level and related shortage of water resources at the late stage of WCC peak time. To solve this problem, artificial recharge techniques has been recently applied to some WCC area. This study introduces infiltration gallery, which is one of the artificial recharge methods, and tentatively examined the effectiveness of three galleries installed at Sangdae-ri WCC area of Cheongju City. Seven galleries are set up at each empty space between eight vinyl houses in this area and its dimension is designed as 50 cm in each width and height and 300 cm in each length. Installation process was including bed excavation, backfill with gravels and silica sands, and completion of gallery by equipment of piezometer and covering with non-woven cloth. For each B, C, D gallery, 3 types of test including preliminary, four step and one long-term injection were performed. The first preliminary test showed the rough relations between injection rates and water level rise as follows; 20 cm and 30 cm level rise for $33.29{\sim}33.84m^3/d$ and $45.60{\sim}46.99m^3/d$ in B gallery; 0 cm, 16 cm and 33 cm level rise for $21.1m^3/d$, $33.98m^3/d$ and $41.69m^3/d$ in C gallery; 29 cm and 42 cm level rise for $48.10m^3/d$ and $52.23m^3/d$ in D gallery. Afterwards, more quantitative results estimating effectiveness of artificial recharge were reasoned out through stepped and long-term injection tests, which is expected to be employed for estimating water quantity re-injected into the aquifer through these galleries by natural injection over the period of WCC peak time.

• Korean Journal of Soil Science and Fertilizer
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• v.32 no.2
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• pp.155-163
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• 1999

Nutrient balance during rice cultivation in the paddy of a local area under the environmental protection for drinking water supply was investigated. To compare nutrient balance in the paddy soil applied with different types of fertilization, 7 treatments were selected as followings : Recommended level of chemical fertilizers(R), Conventional fertilization(CF), Fresh cow manure(FCM), Cow manure compost(CMC), Straw compost+reduced chemical fertilizer(SCF), Fresh straw+recommended level of fertilizers(FSC), and no fertilization as control(C). Here, FCM, CMC and SCF were applied at the same level of total nitrogen as recommended in R. Rice yield was the highest in the recommendation(R) and fresh cow manure (FCM) treatments with $6,730kg\;ha^{-1}$(index 100), and followed by SCF (index 98), FSC (index 98), CMC(index 94), and CF(index 94). But statistically significant difference was not recognized among treatments except the control. Nitrogen infiltration loss was high in the simple chemical fertilizer treatments with $63kg\;ha^{-1}$ in CF and $58kg\;ha^{-1}$ in R during rice cultivation, respectively. Nitrogen infiltration loss was decreased below half level of chemical fertilizer treatments with cow manure treatments ($23kg\;ha^{-1}$ in FCM and $27kg\;ha^{-1}$ in CMC) and with reducing chemical fertilizer treatment by adding straw compost ($25kg\;ha^{-1}$). Phosphate was not leached during rice cultivation in paddy soil of a fluvial deposit type, in which oxidation horizon was developed broadly under around 15 cm depth of surface soil. Phosphate balance (A-B) was closed to 0 in all treatments except cow manure treatment (CMC), in which it was $+30kg\;ha^{-1}$ and show the possibility of over accumulation of phosphate by continuously replicated application of cow manure compost. Potassium balance was negative value in all but straw recycling treatment (FSC). It means that potassium was continuously supplied from soil minerals, uptaken by plants or eluted out of soil. In conclusion, by substituting inorganic fertilizer for organic fertilizer or reducing application rate of chemical fertilizer through mixing organic fertilizer, it would be possible to achieve the same rice yield as in the recommendation treatment and to decrease nutrient leaching below half level in rice paddy soil.

• Restorative Dentistry and Endodontics
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• v.44 no.4
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• pp.40.1-40.10
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• 2019

Objectives: This study aimed to assess the effect of DentalVibe on the level of pain experienced during anesthetic injections using 2 different techniques. Materials and Methods: This randomized crossover clinical trial evaluated 60 patients who required 2-session endodontic treatment. Labial infiltration (LI) anesthesia was administered in the anterior maxilla of 30 patients, while inferior alveolar nerve block (IANB) was performed in the remaining 30 patients. 1.8 mL of 2% lidocaine was injected at a rate of 1 mL/min using a 27-gauge needle. DentalVibe was randomly assigned to either the first or second injection session. A visual analog scale was used to determine participants' pain level during needle insertion and the anesthetic injection. The paired t-test was applied to assess the efficacy of DentalVibe for pain reduction. Results: In LI anesthesia, the pain level was 12.0 ± 15.5 and 38.1 ± 21.0 during needle insertion and 19.1 ± 16.1 and 48.9 ± 24.6 during the anesthetic injection using DentalVibe and the conventional method, respectively. In IANB, the pain level was 14.1 ± 15.9 and 35.1 ± 20.8 during needle insertion and 17.3 ± 14.2 and 39.5 ± 20.8 during the anesthetic injection using DentalVibe and the conventional method, respectively. DentalVibe significantly decreased the level of pain experienced during needle insertion and the anesthetic injection in anterior LI and mandibular IANB anesthesia. Conclusions: The results suggest that DentalVibe can be used to reduce the level of pain experienced by adult patients during needle insertion and anesthetic injection.

• Journal of Soil and Groundwater Environment
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• v.17 no.2
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• pp.28-36
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• 2012

This study carried out several kinds of investigations such as geology, hydrogeology, groundwater level and quality, surface-water quality, and the quantity and quality of groundwater discharge from the subway to identify the causes of groundwater contamination around the subway tunnel at Suyeong District in Busan City. Geostatistical analyses were also conducted to understand the characteristics of groundwater level and quality distributions. There are Kwanganri Beach and Suyeong River in the study area, which are basically influenced by seawater. The total quantities of groundwater utilization and groundwater discharge from the subway tunnel in Suyeong District are 2,282,000 $m^3$/year, which is 2.4 times larger than the sustainable development yield of groundwater. The lowest groundwater level around the subway tunnel is about 32 m below the mean sea-level. The large drawdown of groundwater led to the inflow of seawater and salinized river water toward the subway tunnel, and therefore the quality of groundwater didn't satisfy the criteria of potable, domestic, agricultural and industrial uses. Distribution maps of groundwater level and qualities produced by kriging were very useful for determining the causes of groundwater contamination in the study area. The distribution maps of electrical conductivity, chloride and sulfate showed the extent of seawater intrusion and the forceful infiltration of the salinized Suyeong River. This study revealed that seawater and salinized river water infiltrated into the inland groundwater and contaminated the groundwater around the subway tunnel, because the groundwater level was seriously drawdowned by groundwater discharge from the subway tunnel. The countermeasure for the minimization of groundwater discharge from the subway tunnel is necessary to prevent the groundwater obstacles such as groundwater depletion, groundwater-quality deterioration, and land subsidence.

• Journal of Ecology and Environment
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• v.38 no.3
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• pp.307-318
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• 2015

The objectives of this study were to identify multi-level stressors from blood biomarkers to community-level bioindicators and diagnose the stream ecosystem health in polluted streams. Blood chemistry such as total protein ($T_{Pro}$), blood urea nitrogen ($B_{UN}$), total cholesterol ($T_{Cho}$) and $A_{lb}$umin ($A_{lb}$) were analyzed from sentinel fish tissues; the functions of kidney, gill and liver were significantly decreased in the impacted zone ($I_z$), compared to the control zone ($C_z$). Histopathological analysis showed that fish liver tissues were normal in the $C_z$. Fish liver tissues in the $I_z$, however, showed large cell necrosis and degeneration and also had moderate lobular inflammation and inflammatory cell infiltration of lymphocytic histocytes. Species biotic index (SBI) at species level and stream health assessment (SHA) at community level indicated that chemical impacts were evident in the $I_z$ (ecological health; poor - very poor), and this was matched with the blood tissue analysis and histopathological analysis. The impairments of the streams were supported by water chemistry analysis (nitrogen, phosphorus). Tolerance guild analysis and trophic guild analysis of fish were showed significant differences (P < 0.01) between $C_z$ and $I_z$. Overall, multiple parameter analysis from biomarker level (blood tissues) to bioindicator level (community health) showed significantly greater impacts in the $I_z$ than $C_z$. This approach may be effective as a monitoring tool in identifying the multilateral and forthcoming problems related to chemical pollution and habitat degradation of stream ecosystems.

• Clinical and Experimental Pediatrics
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• v.51 no.7
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• pp.760-765
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• 2008

Paragonimiasis is a parasitic infection that occurs following the ingestion of infectious Paragonimus metacercariae from crabs or crayfish. Pulmonary paragonimiasis is the most common clinical manifestation of this infection, but several ectopic paragonimiasis cases have also been reported. Among them, cases of subcutaneous paragonimiasis are rare, especially in children. We report a case of subcutaneous paragonimiasis of the right abdominal wall with pleural effusion with hepatic involvement and without abnormal pulmonary infiltration in a boy aged 2 years and 5 months. He had eaten soybean sauce-soaked freshwater crabs (kejang) 6 months prior to complaining of right abdominal wall distension. On evaluation, right pleural effusion without abnormal pulmonary infiltration was detected, as well as blood eosinophilia, an elevated serum IgE level, pleural fluid eosinophilia and a positive enzyme-linked immunosorbent assay that detected P. westermani antibody in the serum. Thoracentesis, praziquantel administration, and excision of subcutaneous lesions were performed. After treatment, the eosinophil count and serum IgE level were decreased, and the subcutaneous lesions did not recur. The frequency of paragonimiasis has decreased recently, but it is still prevalent in Korea. Paragonimiasis should be suspected if pleural fluid eosinophilia is associated with blood hypereosinophilia and a high level of serum IgE; however clinicians should obtain a thorough history of travel and food habits.

• The Journal of Internal Korean Medicine
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• v.29 no.4
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• pp.871-886
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• 2008

Objective : Gypsum fibrosum has been traditionally used in treatment of febrile diseases and recently been shown to have anti-inflammatory effect. Chronic renal failure has a serious clinical symptoms including proteinuria, azotemia, anemia, and hyperlipidemia and has characteristic histopathological changes, glomerular hypertrophy, infiltration of inflammatory cells, and crescentic sclerosis, We investigated the effects of gypsum fibrosum on renal functional and histopathological disorder in chronic renal failure rat model induced 5/6 nephrectomy. Methods : Using Sprague-Dawley rats, CRF was induced by 5/6 nephrectomy. The rats were divided into 3 groups, normal, conrol, and gypsum administered orally with gypsum fibrosum 500mg/kg/day. Body weight, 24 hr proteinuria, hematologic analysis, and histological morphologic changes were followed up after 8 weeks. The glomerular macrophage/monocyte infiltration, $TGF-{\beta}_1$, type IV collagen, and angiotensin II type1 receptor($AT_1$) were evaluated by immunohistochemistry. Resuls : In the CRF control group, functional parameters and histopathologic changes clearly indicated the development of CRF. 24 hr proteinuria significantly increased in the CRF control group over the normal group, and serum creatinine level was lower in the gypsum group than in the control group, LDL-cholesterol was significantly lower in the gypsum group than in the control group. Morphological investigations showed a variety of characteristic features of CRF, glomerular hypertrophy, increasing cellular density of glomerulus, deposition of extra-cellular matrix, fibrotic change, and glomerular sclerosis in the control group, but in the gypsum group, these features diminished significantly. In observation of renal type IV collagen and $AT_1$ expression, positive area significantly increased in the control group over the normal group, and it significantly decreased in the gypsum group compared to the control group. Conclusions : Our findings suggest that gypsum fibrosum inhibits $AT_1$ and type IV collagen expression in renal tissues and attenuates progression of glomerulosclerosis and interstitial fibrosis in chronic renal failure rats, which lead to amelioration of renal function. From these results, we suggest that gypsum fibrosum may have renoprotective effects and could be a useful remedy agent for treating chronic renal failure.

• The Journal of Advanced Prosthodontics
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• v.9 no.2
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• pp.104-109
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• 2017

PURPOSE. The purpose of this study was to evaluate the influence of acid etching treatment on surface characteristics and biological response of glass-infiltrated zirconia. MATERIALS AND METHODS. A hundred zirconia specimens were divided into four groups depending on surface treatments: untreated zirconia (group Z); acid-etched zirconia (group ZE); glass-infiltrated zirconia (group ZG); and glass-infiltrated and acid-etched zirconia (group ZGE). Surface roughness, surface topography, surface morphology, and Vickers hardness of specimens were evaluated. For biological response test, MC3T3-E1 cell attachment and proliferation on surface of the specimens were examined. The data were statistically analyzed using one-way ANOVA and Tukey's HSD test at a significance level of 0.05. RESULTS. Group ZGE showed the highest surface roughness ($Ra=1.54{\mu}m$) compared with other groups (P < .05). Meanwhile, the hardness of group Z was significantly higher than those of other groups (P < .05). Cell attachment and cell proliferation were significantly higher in group ZGE (P < .05). CONCLUSION. We concluded that effective surface roughness on zirconia could be made by acid etching treatment after glass infiltration. This surface showed significantly enhanced osteoblast cell response.

• Proceedings of the Korea Water Resources Association Conference
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• 2005.05b
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• pp.1199-1203
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• 2005

Combined sewer overflows(CSOs) are themselves a significant source of water pollution. Therefore, the control of urban drainage for CSOs reduction and receiving water quality protection is needed. Examples in combined sewer systems include downstream storage facilities that detain runoff during periods of high flow and allow the detained water to be conveyed by an interceptor sewer to a centralized treatment plant during periods of low flow. The design of such facilities as stormwater detention storage is highly dependant on the temporal variability of storage capacity available(which is influenced by the duration of interevent dry periods) as well as the infiltration capacity of soil and recovery of depression storage. As a result, a contiunous approach is required to adequately size such facilities. This study for the continuous long-term analysis of urban dranage system used analytical Probabilistic model based on derived probability distribution theory. As an alternative to the modeling of urban drainage system for planning or screening level analysis of runoff control alternatives, this model have evolved that offer much ease and flexibility in terms of computation while considering long-term meteorology. This study presented rainfall and runoff characteristics or the subject area using analytical Probabilistic model. Runoff characteristics manifasted the unique characteristics of the subject area with the infiltration capacity of soil and recovery of depression storage and was examined appropriately by sensitivity analysis. This study presented the average annual COSs and number of COSs when the interceptor capacity is in the range 3xDWF(dry weather flow). Also, calculated the average annual mass of pollutant lost in CSOs using Event Mean Concentration. Finally, this study presented a dicision of storage volume for CSOs reduction and water quality protection.

• Composites Research
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• v.15 no.3
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• pp.1-10
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• 2002

The effect of size of SiC particles and additive Mg content on the mechanical properties and wear characteristics were investigated for the SiCp/AC8A composites fabricated by pressureless infiltration process. Results showed that the hardness and the bending strength increased with decreasing the size of SiC particle. By increasing the Mg content the hardness of SiCp/AC8A composites increased due to the hard reaction products, however the bending strength decreased by formation of coarse precipitates and high porosity level. The SiCp/AC8A composites exhibited about 6 times higher wear resistance compared with AC8A alloy at high sliding velocity and as increasing the particle size, wear resistance was improved. The major wear mechanical of SiCp/AC8A composites exhibited the abrasive wear at low to high sliding velocity whereas AC8A alloy showed adhesive and melt wear at high sliding velocity.