• Environmental Engineering Research
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• v.24 no.1
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• pp.1-16
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• 2019

N-nitrosodimethylamine (NDMA) is a typical nitrogen disinfection by-product, which has posed a potential threat to human health during drinking water disinfection. Because of the well-known effects of mutagenesis, carcinogenesis and teratogenesis, the high detection rate in water engineering systems (such as coagulation, membrane filtration and biological systems), and difficulty to remove, it has received wide concern in the field of water engineering systems. The NDMA is a low molecular weight hydrophilic organic substance, which is difficult to remove. Also, the mechanism for NDMA formation is also recognized to be complex, and many steps still needed to be further evaluated. Therefore, the mechanistic knowledge on NDMA formation potential and their removal processes is of particularly interest. Few papers summarize the occurrence and control of NDMA in water engineering systems. It is for this reason that the content of this paper is particularly important for us to understand and control the amount of NDMA thus reducing the threat of disinfection by-products to drinking water. Four parts including the mechanisms for the NDMA formation potential, the factors affecting the NDMA formation potential, the technologies for removal of NDMA are summarized. Finally, some definite suggestions are given.

• Journal of Korean Society of Environmental Engineers
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• v.33 no.3
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• pp.212-221
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• 2011

Wastewater treatment plants (WWTPs) are required to meet the reinforced discharge standards which are differentiated as 0.2, 0.3 and 0.5 mg-TP/L for the district I, II and III, respectively. Although most of WWTPs are operating advanced biological phosphorus removal system, the supplementary phosphorus treatment facility using chemical addition should be required almost at all WWTPs. Therefore, water quality data from several exemplary full-scale plants operating phosphorus treatment process were analyzed to evaluate the reliability of removal performance. Additionally, a series of jar tests were conducted to find optimal coagulants dose for phosphorus removal by chemical precipitation and to describe characteristics of the reaction and sludge production. Chemical costs and the increasing sludge volume in physicochemical phosphorus removal process were estimated based on the results of jar tests. The minimum coagulant (aluminium sulfate and poly aluminium chloride) doses to keep TP concentration below 0.5 and 0.2 mg/L were around 25 and 30 mg/L (as $Al_2O_3$), respectively, in the mixed liquor of activated sludge. In the tertiary treatment facility, relatively lower coagulant doses of 1/12~1/3 the minimum doses for activated sludge were required to achieve the same TP concentrations of 0.2~0.5 mg/L. Increase in suspended solids concentration due to chemical precipitates in mixed liquor was estimated at 10~11%, compared to the concentration without chemical addition. When coagulant was added into mixed liquor, chemical (aluminium sulfate) cost was estimated to be 4~10 times higher than in secondary effluent coagulation/separation process. Sludge production to be wasted was also 4~10 times higher than secondary effluent coagulation/separation process.

• 제어로봇시스템학회:학술대회논문집
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• 1997.10a
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• pp.317-320
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• 1997

In the water purification plant, chemicals are injected for quick purification of raw water. It is clear that the amount of chemicals intrinsically depends on the water quality such as turbidity, temperature, pH and alkalinity etc. However, the process of chemical reaction to improve water quality by the chemicals is not yet fully clarified nor quantified. The feedback signal in the process of coagulant dosage, which should be measured (through the sensor of the plant) to compute the appropriate amount of chemicals, is also not available. Most traditional methods focus on judging the conditions of purifying reaction and determine the amounts of chemicals through manual operation of field experts or jar-test results. This paper presents the method of deriving the optimum dosing rate of coagulant, PAC(Polymerized Aluminium Chloride) for coagulant dosing process in water purification system. A neural network model is developed for coagulant dosing and purifying process. The optimum coagulant dosing rate can be derived the neural network model. Conventionally, four input variables (turbidity, temperature, pH, alkalinity of raw water) are known to be related to the process, while considering the relationships to the reaction of coagulation and flocculation. Also, the turbidity in flocculator is regarded as a new input variable. And the genetic algorithm is utilized to identify the neural network structure. The ability of the proposed scheme validated through the field test is proved to be of considerable practical value.

• Journal of the Korean Society of Food Science and Nutrition
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• v.27 no.6
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• pp.1204-1210
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• 1998

This study was focused on the purification, characterization and promotion mode of an anticoagulant polysaccharide from Hizikia fusiforme. The anticoagulant crude polysaccharide(HF 0) was obtained by using hot water extraction at 100oC for 3 hrs after homogenizing desalted Hizikia fusiforme. The anticoagulant polysaccharide(HF 2 3 1a) was purified from the crude extract(HF 0) through stepwise gradient ethanol precipitation(HF 2), DEAE Toyopearl 650C(HF 2 3), Sephadex G 75(HF 2 3 1), Sepharose CL 6B(HF 2 3 1a) chromatography and HPLC to homogeneity. HF 2 3 1a was estimated at 5.3$\times$105 Da molecular weight and composed of fucose(51.92%), galactose(19.34%), mannose(13.92%), xylose (7.14%), arabinose(3.95%) and rhamnose(3.78%), and comprimised 29.7 % sulfate residue. The sulfated anticoagulant polysaccharide from HF 2 3 1a was proposed to inhibit via the intrinsic pathway and common pathway in the blood coagulation. The HF 2 3 1a exhibited the anticoagulant activity by activating an antithrombin III and the activity depended on the concentration of HF 2 3 1a. Acute toxicity of HF 2 in mice was not detected. Only 14 of 33 control mice(11.4%) that had taken saline survived for 30 min after injecting thrombin(100 NIH unit/ml).

• Korean Journal of Environmental Biology
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• v.27 no.4
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• pp.391-396
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• 2009

The biological effects of carcinogenic polycyclic aromatic hydrocarbons (cPAHs) including benzo[a]pyrene (BaP), dibenzo[a,h]anthracene (DBA), benzo[a]anthracene (BaA), benzo[b] fluoranthene (BbF), benzo[k]fluoranthene (BkF), and indeno[1,2,3-c, d]pyrene (InP) on transcriptomic changes were determined in the liver of Oryzias latipes. Differentially expressed genes (DEGs) by binary exposure to cPAHs (BaP+BaA, BaP+BbF, BaP+BkF, BaP+DbA, BaP+InP) were screened by annealing control primers-based polymerase chain reaction followed by sequence analysis and BLAST searching. The results showed that four DEGs were commonly expressed by cPAHs and they were identified as ribosomal protein S4, coagulation factor II, elongation factor 1 beta, and a predicted protein similar to human immunodeficiency virus type I enhancer binding protein 3. This finding suggests that binary exposure to cPAHs interferes protein synthesis required for fundamental liver functions in fish.

• Archives of Reconstructive Microsurgery
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• v.2 no.1
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• pp.77-81
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• 1993

Free tissue transplantation is commonly performed with the brilliant achievement in microsurgery and anticoagulants and antithrombotic agents have been prescribed in the procedures. However, there is no clean-cut indication as to which agents would be more effective in every steps and final consequences. Low molecular weight heparins inhibiting coagulation in plateletrich plasma and acting on the vascular endothelium have antithrombotic and fibrinolysis action. The experiment with rat groin free flap transplantation after 6-hour ischemia and injection of the low molecular weight heparin was performed and the results between the injection and non-injection group were analysed as follows, 1. Both of the 24-hour groups, vessel patency was not proportional to color change of the groin flap. 2. On the second day after anastomois, heparin-injection group showed intact intima, patent lumen without thrombus, and mild granulomatous inflammation around the suture material and control group with doubtful patency revealed intimal loss and thrombus formation. 3. On the 5th, 7th, and 9th postoperative day, heparin group was patent in anastomosis and showed acute inflammatory cells. 4. The 7th-week period, heparin-injection group showed intact flap color, patent lumen with intact intima and persistent foreign body granuloma.

• Journal of Chest Surgery
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• v.20 no.4
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• pp.683-687
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• 1987

Bleeding from bone marrow after sternotomy for open cardiac surgery can be sometimes difficult to control and even lead to reoperation for hemostasis. A clinical comparative study was carried out to demonstrate the hemostatic effect of fibrin glue [Beriplast] for sternal marrow bleeding after sternotomy for open heart surgery. Postoperative blood loss was measured in two patient groups, group A included 19 patients operated upon from June to October 1987 and the fibrin glue was applied to the sternal marrow together with collagen fleece and group B consisted of 22 patients from January to May 1987 and only collagen fleece was applied without fibrin glue. There was no difference between two groups in age and sex distributions, coagulation state, method of extracorporeal circulation and operative management. The blood loss one hour after operation was 2.04 ml/hr/kg in group A and 3.55 ml/hr/kg in group B [P<0.001]. The most significant difference was observed during the first 4 hours after surgery with 1.34 ml/hr/kg versus 2.05 ml/hr/kg. over the following 20 hours the amount of drainage from the chest tubes was identical in both groups. Fibrin glue reduces blood loss after open heart surgery by local hemostasis at sternum. Our study has shown that local application of fibrin glue to sternal marrow is an effective method of controlling the sternal bleedings. No side effect or complication of fibrin glue was noted.

• Journal of The Korean Dental Society of Anesthesiology
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• v.2 no.2 s.3
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• pp.114-117
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• 2002

Special anesthetic considerations were required for children with acute or chronic liver disease. We experienced a case of dental treatment to control infection under general anesthesia in the 2-year-old girl with liver failure. She was also scheduled for liver tansplantation. Her preanesthetic results of liver function test, electrolytes, and coagulation panel were unstable and out of normal ranges. Uneventful anesthetic induction using isoflurane and atracurium and nasotracheal intubation were carried out. General anesthesia was maintained with isoflurane for 2 hours. Oozing from multiple extraction sites was sustained, so the transfusion of platelet concentration 1 units, fresh frozen plasma 1 unit, and packed red blood cell 1 unit was done. She was recovered without complication but was transferred to pediatric intensive care unit for wound care with her endotracheal tube kept. She was transferred to a ward without noticeable complications next day. So we report this successful case of anesthetic management for dental treatment in a child with liver failure.

• Journal of Korean Society of Water and Wastewater
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• v.31 no.2
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• pp.169-175
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• 2017

This study applied microbubbles to reduce membrane fouling in wastewater reuse membrane processes, evaluated and compared the transmembrane pressure with or without the application of microbubbles and the cleaning efficiency with the application of aeration and microbubbles. In addition, this study analyzed foulants removed from the membrane surface. Changes in the transmembrane pressure of membranes with the presence or absence of microbubbles were observed. As a result, transmembrane pressure (TMP) increasing rate decreased twofold when applying microbubbles to realize stable operations. This study compared and evaluated cleaning efficiency applying aeration and microbubbles. As a result, the cleaning efficiency was 5% higher on average when applying microbubbles. In turbidity and total organic carbon (TOC), foulants were discharged when applying microbubbles twice as much as applying aeration. It is thought that particulate foulants precipitated on the membrane surface were more likely to desorb because the adhesion between the membrane surface and particle was weakened by microbubbles. Therefore, it is considered possible to effectively control membrane fouling because of the increase in cleaning efficiency when applying microbubbles to wastewater reuse membrane processes.

• International Journal of Oral Biology
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• v.43 no.2
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• pp.83-91
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• 2018

Nonthermal atmospheric plasma has been studied for its many biomedical effects, such as tooth bleaching, wound healing, and coagulation. In this study, the effects of dentinal tubules occlusion were investigated using fluoride-carboxymethyl cellulose (F-CMC) gel, nano-sized hydroxyapatite (n-HA), and nonthermal atmospheric plasma. Human dentin specimens were divided to 5 groups (group C, HA, HAF, HAP, and HAFP). Group HA was treated with n-HA, group HAF was treated with n-HA after a F-CMC gel application, group HAP was treated with n-HA after a plasma treatment and group HAFP was treated with n-HA after a plasma and F-CMC gel treatment. The occlusion of dentinal tubules was investigated using scanning electron microscopy (SEM) and energy dispersive x-ray spectroscopy (EDS), which shows Ca/P ratio. In the EDS results, a higher Ca/P ratio was shown in the groups including n-HA than in the control group. The specimens of group HAP and HAFP had a higher Ca/P ratio in retentivity. In the SEM results, there was not a significant difference in the amount of times applied. Therefore, this study suggests F-CMC gel and n-HA treatment using nonthermal atmospheric plasma will be a new treatment method for decreasing hypersensitivity.