• Journal of Korean Society of Environmental Engineers
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• v.22 no.12
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• pp.2149-2161
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• 2000

Nonliving Absidia coerulea and Thraustochitrium sp. were used as biosorbents to remove lead and cobalt that are one of representative pollutant in wastewater and radioactive liquid waste. The optimum pH range for maximum lead and cobalt removal was increased 6.5~11.4 and 8.6~12.0 for Absidia coerulea and 4.2~10.5 and 8.9~11.6 for Thraustochitrium sp. to compared to biosorbent-free control, pH of 8.4~11.2 and 10.5~11.5, respectively. With 1 g biosorbent/L at initial solution pH 5.0. Absidia coerulea and Thraustochitrium sp. took up lead from aqueous solutions to the extent of 104 and 125 mg/g biomass, respectively, whereas Absidia coerulea and Thraustochitrium sp. at initial pH 6.0 took up only 2 and 20 mg/g biomass of cobalt, respectively. For initial 500 mg Pb/L at initial pH 5.0. optimum amount of biosorbent for maximum lead uptake was 0.2 g/L for Absidia coerulea and Thraustochitrium sp., whereas optimum 3.0 g biosorbent/L was needed for initial 200 mg Co/L at initial pH 6.0. Absidia coerulea and Thraustochitrium sp. had higher adsorption capacity for lead than that of cobalt.

• Journal of Chest Surgery
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• v.45 no.6
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• pp.380-389
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• 2012

Background: Bovine pericardium is one of the most widely used materials in bioprosthetic heart valves. Immunologic responses have been implicated as potential causes of limited durability of xenogenic valves. This study aimed to determine the effectiveness of decellularization and ${\alpha}$-galactosidase (${\alpha}$-gal) to remove major xenoreactive antigens from xenogenic tissues. Materials and Methods: Recombinant Bacteroides thetaiotaomicron (B. thetaiotaomicron) ${\alpha}$-gal or decellularization, or both were used to remove ${\alpha}$-gal from bovine pericardium. It was confirmed by ${\alpha}$-gal-bovine serum albumin-based enzyme-linked immunosorbent assay (ELISA), high-performance anion exchange chromatography, flow cytometry, 3,3'-diaminobenzidine-staining, and lectin-based ELISA. The mechanical properties of bovine pericardium after decellularization or ${\alpha}$-gal treatment were investigated by tests of tensile-strength, permeability, and compliance. Collagen fiber rearrangement was also evaluated by a 20,000${\times}$ transmission electron microscope (TEM). Results: Recombinant B. thetaiotaomicron ${\alpha}$-gal could effectively remove ${\alpha}$-gal from bovine pericardium B. thetaiotaomicron (0.1 U/mL, pH 7.2) while recombinant human ${\alpha}$-gal removed it recombinant human ${\alpha}$-gal (10 U/mL, pH 5.0). There was no difference in the mechanical properties of fresh and recombinant ${\alpha}$-gal-treated bovine pericardium. Furthermore, the TEM findings demonstrated that recombinant ${\alpha}$-gal made no difference in the arrangement of collagen fiber bundles with decellularization. Conclusion: Recombinant B. thetaiotaomicron ${\alpha}$-gal effectively removed ${\alpha}$-gal from bovine pericardium with a small amount under physiological conditions compared to human recombinant ${\alpha}$-gal, which may alleviate the harmful xenoreactive immunologic responses of ${\alpha}$-gal. Recombinant ${\alpha}$-gal treatment had no adverse effects on the mechanical properties of bovine pericardium.

• Journal of the Korean Society of Marine Environment & Safety
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• v.25 no.6
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• pp.809-818
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• 2019

Since January 1, 2020, the International Maritime Organization (IMO) has put in place strong regulations to reduce air pollution caused by ships by lowing the upper limit of ship fuel oil sulfur content from 3.5% to 0.5% for ships passing through all sea areas around the world. Although it is important to reduce air pollutants by using fuel oil with low sulfur content, reducing the amount of energy waste through the economic operation of a ship can also help reduce air pollutants. Ships can follow designated routes accurately even under the influence of noise using autopilot systems. However, regardless of their quality, the performance of these systems is af ected by noise; heading angles with added measurement noise from the gyroscope are input into the autopilot system and degrade its performance. A technique to solve these problems reduces noise effects through the application of a Kalman filter, which is widely used in condition estimation. This method, however, cannot completely eliminate the effects of noise. Therefore, to further improve noise removal performances, in this study we propose a better denoising method than the Kalman filter technique by applying a multi-layer perceptron (MLP) in forward direction motion and a Kalman Filter in rotation motion. Simulations show that the proposed method improves forward direction motion by preventing the malfunction of a rudder more so than merely using a Kalman Filter.

• Korean Chemical Engineering Research
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• v.43 no.4
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• pp.537-541
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• 2005

A bubbling fluidized bed reactor was used to study $CO_2$ capture from flue gas using a sodium-based dry regenerable sorbent, sorbA which was manufactured by Korea Electric Power Research Institute. A dry sorbent, sorbA, consists of $Na_2CO_3$ for absorption and supporters for mechanical strength. $CO_2$ capture was effective in the lower temperature range of $50-70^{\circ}C$, while regeneration occurred in the range of $120-300^{\circ}C$. To increase initial $CO_2$ removal, some amount of steam was absorbed in the sorbents before injecting simulated flue gas. It was possible to remove most $CO_2$ for 1-2 minutes at $50^{\circ}C$ and residence time of 2 seconds with steam pretreatment. Little or no reduction in initial reaction rate and capture capacity was observed in multicycle tests. The carbonated and regenerated sorbent samples were analyzed by NMR to confirm the extent of reaction. The results obtained in this study can be used as basic data for the scale-up design and operation of the $CO_2$ capture process with two fluidized bed reactors.

• Journal of Periodontal and Implant Science
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• v.25 no.3
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• pp.703-719
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• 1995

The purpose of this study was to observe the effects of the periodontal ligament on the healing and the formation of alveolar bone in the extraction socket, when this ligament had artificially remained in the socket during the tooth removal. Twenty rats aged 4 weeks were used and devided into the control groups (10) and the experimental groups (10) in this study. The maxillary right and left first molars were extracted in both groups. In the experimental groups the periodontal ligament was remained in the extraction sockets using 0.4% ${\beta}-aminopropionitrile$, and in the control the periodontal ligament was completely removed by curettage. At 1, 3, 5, 7 and 14 days after the tooth extraction, rats in both groups were serially sacrificed. And the specimens were prepared with Hematoxylin-Eosin stain for the light microscopic evaluation. The results of this study were as follows ; 1. On 1 day, the periodontal ligament was only found in the extraction socket walls of the experimental groups, and there was not the distinguishable difference between the control and the experimental groups. 2. On 3 days, there were more collagen fibers and the appearance of higher cellular density in the experimental groups than in the control. And the cells and collagen of the periodontal ligament were so actively proliferated and synthesized that invaded into the connective tissue of the extraction sockets in the experimental groups. 3. In the experimental groups, the trabecular bone was formed on the basal and lateral bone surface on 5 days. However, there was not the new bone forming appearance in the control groups at this time. 4. On 7 days, the trabecular bone was formed in the control groups. 5. On 14 days, the extraction sockets were almost entirely filled with the bony trabeculae in both groups. But, compared to the control group, the experimental groups showed the prominent differences in the amount & the density of the new bone formed. In conclusion, it was suggested that the residual periodontal ligament tissue in the extraction socket will play a major role as the important cell source in the healing and the new bone formation of the extraction socket.

• Journal of Radiation Protection and Research
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• v.27 no.1
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• pp.27-35
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• 2002

Characteristics of Amberlite IRN 77, a cation exchange resin, and the mechanisms of its adsorption equilibria with Co(II), Ni(II), Cr(III) and Fe(III) ions were investigated for the application of the demineralizing process in the primary coolant system of a pressurized water reactor (PWR). The optimum dosage of the resin for removal of the dissolved metal ions at $200mgL^{-1}$ was 0.6 g for 100 mL solution. Most of each metal ion was adsorbed onto the resin in an hour from the start of the reaction. Each metal adsorption onto the resin could be well represented by Langmuir isotherms. However, in the case of Fe(III) adsorption, continuous formation of Fe-oxide or -hydroxide and its subsequent precipitation inhibited the completion of the equilibrium between the metal and the adsorbent Cobalt(II) and Ni(II), which have an equivalent electrovalence, were adsorbed to the resin with a similar adsorption amount when they coexisted in the solution. However, Cr(III) added to the solution competitively replaced Co(II) and Ni(II) which were already adsorbed onto the resin, resulting in desorption of these metals into the solution. The result was likely due to a higher adsorption affinity of Cr(III) than Co(II) and Ni(II). This implies that the interactively competitive adsorption of multi-cations onto the resin should be fully considered for an efficient operation of the demineralizing ion exchange process in the primary coolant system.

• Journal of Korean Society of Forest Science
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• v.84 no.2
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• pp.198-206
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• 1995

The objective of this study was to determine the rate of nitrogen mineralization at clearcut and uncut in oak(Quercus rubra L.) and pine(Pinus resinosa Ait.) stands. The study sites were located in northern Lower Michigan, U.S.A. Nitrogen mineralization rates in the top 15cm of mineral soil were examined during the 1991 and 1992 growing seasons(May-October) using an in situ buried tag technique. diet nitrogen mineralization in oak stands over the course of both growing seasons was 67kg/ha in the clearcut and 30kg/ha in the uncut stands. In contrast, net nitrogen mineralization in pine stands was 27kg/ha and 13kg/ha for the same treatments. Total net nitrogen mineralization rates were always higher in oak stands than in pine stands. Extractable $NO_3^-$ before and after one month soil incubation in both oak and pine stands was generally not detectable in the uncut stands, but in the pine clearcut treatment(nitrification over the course of both growing seasons : 3.3kg/ha). The results indicated that : 1) substantial increases in the amount of available soil nitrogen occurred following clearcuts in both stands : and 2) the loin rates of nitrification may be an important mechanism for retention of nitrogen in both oak and pine stands.

• Applied Chemistry for Engineering
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• v.29 no.5
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• pp.541-548
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• 2018

In this work, the $N_2O$ decomposition catalyst and reaction characteristics to control the $N_2O$ removal were described. Experiments were carried out by using Rh as an active metal catalyst on various supports and the $Rh/CeO_2$ catalyst with $CeO_2$ support showed the best activity for the $N_2O$ decomposition when it was prepared under the constant heat treatment condition ($500^{\circ}C$-4 hr). $H_2-TPR$ and XPS analyzes were performed to confirm the effect of the physical and chemical properties of the catalyst on $N_2O$ decomposition. As a result, it was found that the increase of the oxygen transfer capacity of the catalyst due to the increase of both the redox property and $Ce^{3+}$ amount affected the decomposition reaction of $N_2O$. In addition, the future work will include a treatment process capable of decomposition $N_2O$ and NO under the condition that $N_2O$ and NO are simultaneously generated and its characteristics of $N_2O$ decomposition reaction.

• Clinical and Experimental Reproductive Medicine
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• v.24 no.1
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• pp.135-141
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• 1997

The early studies demonstrated that the relative amount of FSH was important for stimulating normal ovarian activity and demonstrated the existence of a threshold level for FSH, above which follicular growth was activated. It was found that only a modest increase in circulating FSH level above the threshold (between 10 and 30%) was required to stimulate folliculogenesis. In addition, FSH is primary responsible for initiating estradiol production through the activation of the aromatase enzyme system in granulosa cells, follicular secretion and growth. LH on the other hand, plays a supportive role in ovarian steroidogenesis, stimulating the ovarian thecal cells to produce androgen, the precursor for estradiol synthesis. But there is now an increasing number of reports in the literature demonstrating an adverse effect of LH on fertility and miscarriage in infertile and fertile women. So HP-FSH is the drug of a highly purified FSH preparation which has a higher specific activity and far fewer impurities than FSH. This study was performed to evaluate the efficacy and safety of HP-FSH administered (SC; subcutaneous) versus FSH(IM; intramuscular) for ovulation induction. 20 candidates patients for ovulation induction were participated. All patients underwent pituitary desensitizing with a long gonadotropin-releasing hormone (GnRH) agonist protocol and ovulation induction was started with HP-FSH SC (10 patients; group I) or FSH IM (10 patients; group II). After ovulation, outcome of ovulation induction and local reaction of injection site were compared. There were no difference of outcome of ovulation in two groups except pregnancy rate/embryo transfer. Group I had a higher pregnancy rate/ embryo transfer than Group II (44.4% Vs 28.6%). Pain, redness, tenderness, bruising and itching when the injection received on the first 5 days of treated (50 SC and 50 IM injections) were assessed. There were no significant difference (P>0.05) in the incidence of tenderness, bruising and itching between the IM and SC injection. But IM injection (FSH) had a tendency of higher above incidence. The number of reports of pain, redness were significantly increased in IM injection group (P<0.05). These results indicate that SC administration of HP-FSH has been shown to be as effect for superovulation as traditional gonadotropins, with an improved safety profile due to the removal of extaneous proteins.

• Applied Chemistry for Engineering
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• v.10 no.4
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• pp.581-585
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• 1999

The surface treated hydroxypropyl methylcellulose(HPMC) which could adjust the soluble time was synthesized when 40 wt % glyoxal solution and $KH_2PO_4$ were sprayed and reacted. And also, the solution dynamic at different ratios of two adding agents were identified If the surface of HPMC was treated with only glyoxal, the dispersion characteristics at different ratios of two adding agents were identified If the surface of HPMC was treated with only glyoxal, the dispersion was observed in the neutral solution and the viscosity was increased after directly dissolved as the solution become alkali condition. But the fine-powder type of HPMC which reacted with glyoxal and $KH_2PO_4$ was dispersed regardless of pH of solution and observed that it was dissolved and its viscosity increased after elapsing some time. With increasing amount of glyoxal and $KH_2PO_4$, the soluble time was delayed. The reaction condition was about 60 min at $75{\sim}85^{\circ}C$. Especially, the removal process of organic solvent after reaction was not required due to reaction under water solution without organic during glyoxal and $KH_2PO_4$ treatment. And also, the HPMC which could adjust the soluble rate in water or organic solvent by changing the degree of substitution of HPMC was synthesized.