• Resources Recycling
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• v.28 no.1
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• pp.47-54
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• 2019

In this study, the wastes were used as fuels for direct reduction iron (DRI) production to reduce production cost and recycle the wastes. We examined the effects of wastes on the reduction behavior of DRI manufacture and the possibility of using wastes as auxiliary fuels. The proximate and Ultimate analysis were carried out to confirm the properties of wastes as fuels, and high-quality reduced irons were fabricated by using the waste as an auxiliary fuel. The metallization of reduced irons increased as the calorific value increase of auxiliary fuel. Especially, the reduced irons fabricated from the waste tires and vinyl plastics which had high heat energy and volatile matters showed higher metallization than the others. The high calorific value and volatility of waste were significant properties as fuel. The high quality DRI could be fabricated with wastes as auxiliary fuels through optimization of reaction conditions.

• Korean Journal of Clinical Laboratory Science
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• v.55 no.4
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• pp.261-268
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• 2023

[¹⁸F]Fluorocholine is a radiopharmaceutical used non-invasively in positron emission tomography to diagnose parathyroid adenoma, prostate cancer, and hepatocellular carcinoma by evaluating the choline metabolism. In this study, a radiolabeling method for [¹⁸F]fluorocholine was optimized using a solid phase extraction (SPE) cartridge. [¹⁸F]Fluorocholine was labeled in two steps using an automated synthesizer. In the first step, dibromomethane was reacted with [¹⁸F]KF/K2.2.2/K₂CO₃ to obtain the intermediate [¹⁸F]fluorobromomethane. In the second step, [¹⁸F]fluorobromomethane was passed through a Sep-Pak^Ⓡ Silica SPE cartridge to remove the impurities and then reacted with N,N-dimethylaminoethanol (DMAE) in a Sep-Pak^Ⓡ C18 SPE cartridge to label [¹⁸F]fluorocholine. The reaction conditions of [¹⁸F]fluorocholine were optimized. The synthesis yield was confirmed according to the number of silica cartridges and DMAE concentration. No statistically significant difference in the synthesis yield of [¹⁸F]fluorocholine was observed when using four or three silica cartridges (P>0.05). The labeling yield was 11.5±0.5% (N=4) when DMAE was used as its original solution. On the other hand, when diluted to 10% with dimethyl sulfoxide, the radiochemical yield increased significantly to 30.1±5.2% (N=20). In conclusion, [¹⁸F]Fluorocholine for clinical use can be synthesized stably in high yield by applying an optimized synthesis method.

• Korean Chemical Engineering Research
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• v.47 no.6
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• pp.762-767
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• 2009

In this study, the feasibility of using vegetable oil extracted from tropical crop seed as a biodiesel feedstock was investigated by producing biodiesel and analysing the quality parameters as a transport fuel. In order to produce biodiesel efficiently, two step reaction process(pre-treatment and transesterificaion) was required because the tropical crop oil have a high content of free fatty acids. To determine the suitable acid catalyst for the pre-esterification, three kinds of acid catalysts were tested and sulfuric acid was identified as the best catalyst. After constructing the experimental matrix based on RSM and analysing the statistical data, the optimal pre-treatment conditions were determined to be 26.7% of methanol and 0.982% of sulfuric acid. Trans-esterification experiments of the pre-esterified oil based on RSM were carried out, then discovered 1.24% of KOH catalyst and 22.76% of methanol as the optimal trans-esterification conditions. However, the quantity of KOH was higher than the previously established KOH concentration of our team. So, we carried out supplemental experiment to determine the quantity of catalyst and methanol. As a result, the optimal transesterification conditions were determined to be 0.8% of KOH and 16.13% of methanol. After trans-esterification of tropical crop oil, the produced biodiesel could meet the major quality standard specifications; 100.8% of FAME, 0.45 mgKOH/g of acid value, 0.00% of water, 0.04% of total glycerol, $4.041mm^2/s$ of kinematic viscosity(at $40^{\circ}C$).

• Applied Biological Chemistry
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• v.43 no.3
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• pp.218-224
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• 2000

The efforts were made to optimite ethanol extraction from persimmon leaf with the time of extraction$(1.5{\sim}2.5\;hrs)$, the temperature of extraction$(70{\sim}90^{\circ}C)$, and the concentration of ethanol$(0{\sim}40%)$ as three primary variables together with several functional characteristics of persimmon leaf as reaction variables. The conditions of extraction was best fitted by using response surface methodology through the center synthesis plan, and the optimal conditions of extraction were established. The contents of soluble solid and soluble tannin went up as the concentration of ethanol went up and the temperature of extraction went down, and the turbidity went down as the concentration of ethanol went down. Electron donation ability was hardly affected by the extraction temperature and had the tendency to go up as the concentration of ethanol went up. The inhibitory activity of xanthine oxidase(XOase) had the tendency to go up as both the concentration of ethanol and the temperature of extraction went up. The inhibitory activity of angiotensin converting enzyme(ACE), the significance of which still was not recognized, showed the maximum when the concentration of ethanol was 27%. In result, the optimal conditions of extraction was the extraction time of two hours, the extraction temperature of $75{\sim}81^{\circ}C$, and the ethanol concentration of $33{\sim}35%$.

• Journal of Nutrition and Health
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• v.47 no.1
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• pp.12-22
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• 2014

Purpose: This study was conducted to establish the production conditions through optimization of the production process of beverages using Aspergillus oryzae CF1001, and to analyze volatile compounds and antidiabetic activity. Methods: The optimum condition was selected using the response surface methodology (RSM), through a regression analysis with the following independent variables gelatinization temperature (GT, $X_1$), saccharogenic time (ST, $X_2$), and dependent variable; ${\Delta}E$ value (y). The condition with the lowest ${\Delta}E$ value occurred with combined 45 min ST and $50^{\circ}C$ GT. The volatile compounds were analyzed quantitatively by GC-MS. Results: Assessment of antidiabetic activity of saccharogenic mixed grain beverage (SMGB) was determined by measurement of ${\alpha}$-glucosidase inhibition activity, and glucose uptake activity and glucose metabolic protein expression by reverse transcriptase polymerase chain reaction (RT-PCR) and western blot analysis. Results of volatile compounds analysis, 62 kinds of volatile compounds were detected in SMGB. Palmitic acid (9.534% ratio), benzaldehyde (8.948% ratio), benzyl ethyl ether (8.792% ratio), ethyl alcohol (8.35% ratio), and 2-amyl furan (4.826% ratio) were abundant in SMGB. We confirmed that ${\alpha}$-glucosidase inhibition activity, glucose uptake activity, and glucose-metabolic proteins were upregulated by SMGB treatment with concentration dependent manner. Conclusion: Saccharogenic mixed grain beverage (SMGB) showed potential antidiabetic activity. Further studies will be needed in order to improve the taste and functionality of SMGB.

• Korean Chemical Engineering Research
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• v.58 no.4
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• pp.541-549
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• 2020

The Drug Delivery System (DDS) is defined as a technology for designing existing or new drug formulations and optimizing drug treatment. DDS is designed to efficiently deliver drugs for the care of diseases, minimize the side effects of drug, and maximize drug efficacy. In this study, the optimization of tripolyphosphate (TPP) concentration on the size of Chitosan nanoparticles (CNPs) produced by crosslinking with chitosan was measured. In addition, the characteristics of Fe₃O₄-CNPs according to the amount of iron oxide (Fe₃O₄) were measured, and it was confirmed that the higher the amount of Fe₃O₄, the better the characteristics as a magnetic drug carrier were displayed. Through the ninhydrin reaction, a calibration curve was obtained according to the concentration of γ-aminobutyric acid (GABA) of Y = 0.00373exp(179.729X)-0.0114 (R² = 0.989) in the low concentration (0.004 to 0.02 wt%) and Y = 21.680X-0.290 (R² = 0.999) in the high concentration (0.02 to 0.1 wt%). Absorption was constant at about 62.5% above 0.04 g of initial GABA. In addition, the amount of GABA released from GABA-Fe₃O₄-CNPs over time was measured to confirm that drug release was terminated after about 24 hr. Finally, GABA-Fe₃O₄-CNPs performed under the optimal conditions were spherical particles of about 150 nm, and it was confirmed that the properties of the particles appear well, indicating that GABA-Fe₃O₄-CNPs were suitable as drug carriers.

• Clean Technology
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• v.28 no.4
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• pp.309-315
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• 2022

Research was conducted to derive the optimal operation conditions and the optimal cathode for using a DSA electrode as an anode to minimize electrode consumption during the removal of nitrogen from wastewater by the electro-chemical method. Of the various electrodes tested as cathodes, brass was determined to be the optimal electrode. It had the highest NO₃-N removal rate and the lowest concentration of residual NH₃-N, a by-product when Cl is present in the solution. Investigating the effect of current density found that when the initial concentration of NO₃-N was 50 mg L^-1, the optimal current density was 15 mA cm^-2. In addition, current densities above 15 mA cm^-2 did not significantly affect the NO₃-N removal rate. The effect of electrolytes on removing NO₃-N and minimizing NH₃-N was investigated by using Na₂SO₄ and NaCl as electrolytes and varying the reaction times. When Na₂SO₄ and NaCl are mixed at a ratio of 1.0 g L^-1 to 0.5 g L^-1 and reacted for 90 min at a current density of 15 mA cm^-2 and an initial NO₃-N concentration of 50 mg L^-1, the removal rate of NO₃-N was about 48% and there was no residual NH₃-N. On the other hand, when using only 1.5 g L^-1 of NaCl as an electrolyte, the removal rate of NO₃-N was the highest at about 55% and there was no residual NH₃-N.