• Bulletin of the Korean Chemical Society
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• v.28 no.2
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• pp.276-280
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• 2007

In this work, caffeine and some catechin compounds + C, EC, EGC, and EGCG were extracted from green tea by using molecular imprinted polymers (MIP) as sorbent materials in a solid-phase extraction (SPE) process known as MISPE (molecular imprinted solid-phase extraction). For synthesis of MIP, caffeine was employed as the template, MAA as the monomer, EGDMA as the crosslinker, and AIBN as the initiator. A solution of caffeine (0.2 mg/mL in methanol) was utilized in the solid extraction cartridges following loading, washing, and elution procedures with acetonitrile, methanol, and methanol-acetic acid (90/10, %v/v) as the solvents, respectively. This solid-phase extraction protocol was applied for the extraction of caffeine and some catechin compounds from green tea. A comparison was made between the results obtained with the MIP cartridges and a traditional C18 reversed-phase cartridge. It was thereupon found that the recovery of caffeine by the MIPbased sorbent used in this work was almost two and four times greater than that by a commercially available C18 material. A quantitative analysis was conducted by high performance liquid chromatography (HPLC) using a C18 column (5 μm, 250 × 4.6 mm) with methanol/water (40/60, %v/v) as the mobile phase at a flow rate of 0.5 mL/min.

• International Journal of Industrial Entomology and Biomaterials
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• v.29 no.2
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• pp.179-184
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• 2014

Silkworm (Bombyx mori ) feces have long been used in the pharmaceutical and food industries as a natural colorant. However, there is limited data on the bioactive compounds that constitute silkworm feces. This research emphasizes the antioxidant activity of different solvent and flavonoid extracts of silkworm feces. The solvents were ethanol, butanol, and water, while the methods utilized included ultrasonification, stirrer, reflux, and reflux after ultrasonification extraction. Results showed that butanol ultrasonification extraction (BUE) yield the lowest extraction (1.75%), while the other methods yielded 7 to 14%. The total polyphenol content utilizing BUE was 3.3 mg TAE/g, while water ultrasonification extraction (WUE) yielded the highest extraction rate with 51.6 mg TAE/g. The total flavonoid content was significantly higher using ethanol reflux extraction (EUE) at 266.8 mg QRE/g BUE, which was 158.3 and 151.3 mg QRE/g. Both DPPH radical scavenging activity and SOD-like (superoxide dismutase) activity, showed significant antioxidant effects. Finally, all other extracts except for BUE had a-glucosidase inhibition at 60%. Therefore, an effective extraction method for physiologically active substances must be selected.

• The Journal of the Korean dental association
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• v.57 no.6
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• pp.326-332
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• 2019

Extraction treatment has been used for a long time to treat crowding or lip protrusion patients and still extraction decision is the most difficult and important decision during diagnosis and treatment planning. If the amount of crowidng is severe, premolar extraction is often considered. Because of their location, premolar extractions would seem to allow for the most straightforward relief of crowding and the improvement of soft tissue profile. But patients and their parents often prefer nonextraction approach if possible and such a preference gives us serious question about the boundary of nonextraction treatment. Because Orthodontic Mini-Implant (OMI) become popular these days, distalization of posterior teeth can be obtained easily without patient's compliance. For this reason, many orthodontists are trying to treat crowding patient with nonextraction than before. But sometime, unexpected side effects are observed including unesthetic profile, impaction of second molar and long treatment time. All the tools for space gaining - extraction, arch expansion, molar distalization and interproximal enamel reduction - have their limitations and indications. Possible side effects and limitations should be carefully considered during the treatment planning. Although Korean patients usually require extraction more often than US or European patients, more knowledge about the tools for space gaining would help us to decrease the rate of extraction and the problems during treatment of crowding patients.

• Journal of KIISE:Databases
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• v.34 no.4
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• pp.343-356
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• 2007

Due to advances in position monitoring technologies such as global positioning systems and sensor networks, recent position information of moving objects has the form of streaming data which are updated continuously and rapidly. In this paper we propose an efficient trajectory maintenance method that stores the streaming position data of moving objects in the limited size of storage space and estimates past positions based on the stored data. For this, we first propose a new concept of incremental extraction of position information. The incremental extraction means that, whenever a new position is added into the system, we incrementally re-compute the new version of past position data maintained in the system using the current version of past position data and the newly added position. Next, based on the incremental extraction, we present an overall framework that stores position information and estimates past positions in the stream environment. We then propose two polynomial-based methods, line-based and curve-based methods, as the method of estimating the past positions on the framework. We also propose three incremental extraction methods: equi-width, slope-based, and recent-emphasis extraction methods. Experimental results show that the proposed incremental extraction provides the relatively high accuracy (error rate is less than 3%) even though we maintain only a little portion (only 0.1%) of past position information. In particular, the curve-based incremental extraction provides very low error rate of 1.5% even storing 0.1% of total position data. These results indicate that our incremental extraction methods provide an efficient framework for storing the position information of moving objects and estimating the past positions in the stream environment.

• Korean Journal of Food Science and Technology
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• v.33 no.1
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• pp.149-152
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• 2001

Extraction characteristics of anthocyanin pigment from red flower cabbage(Brassica oleracea L. var. acephala) as a new source of natural food colorant were investigated. The pigment extracted from red flower cabbage showed the characteristic bathochromic shift of the maximum wavelength of light absorption(${\lambda}_{max}$) as pH of the solution changed from pH 1 to 12. As the concentration of citric acid in the extraction solvent increased, extraction rate and total optical density(TOD) of the extract increased. Maximum TOD was obtained by using the extracting solvent including $0.8{\sim}1.0%$ citric acid and stable pigment solution was obtained by using the extracting solvent including $10{\sim}20%$ ethanol in distilled water. As a result, 10% ethanolic solution with 0.8% citric acid was decided as the optimum extraction solvent for the anthocyanin pigment from red flower cabbage. Within the experimental ranges, the extraction rate increased and therefore extraction time decreased as the extraction temperature increased. The times to reach a certain value of TOD i.e., 2.1 were 24, 8, 4 and 2 hours at extraction temperature of 5, 20, 40 and $60^{\circ}C$, respectively.

• Proceedings of the Acoustical Society of Korea Conference
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• 1994.06a
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• pp.963-970
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• 1994

In speech signal processing, it is very important to detect the pitch exactly. The algorithms for pitch extraction that have been proposed until now are not enough to detect the fine pitch in speech signal. Thus we propose the new algorithm which takes advantage of the G-peak extraction. It is the method to find MZCI(maximum zer-crossing interval) which is defined as cut-off bandwidth rate of LPF (low pass filter)and detect the pitch period of the voiced signals. This algorithm performs robustly with a gross error rate of 3.63% even in 0 dB SNR environment. The gross error rate for clean speech is only 0.18%. Also it is able to process all course with speed.

• Transactions of the Korean Society of Automotive Engineers
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• v.23 no.1
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• pp.1-10
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• 2015

In urban area, since multipath and signal attenuations frequently occur due to street trees, street lights and buildings, it is difficult to obtain accurate navigation solution using GPS. As these problems also impact negatively on the INS/GPS coupled system, implementing advanced transportation systems such as autonomous navigation system and Intelligent Transportation System (ITS) become quite hard. For this reason, to alleviate deterioration of navigation system performance in urban area, direction information extraction algorithm using vision system is proposed in this paper. 2D Finite Rate of Innovation (FRI) technique is applied to extract lane edges. The proposed technique is simulated using road images and feasibility of proposed technique is analyzed through the simulation results.

• Imaging Science in Dentistry
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• v.32 no.1
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• pp.1-10
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• 2002

Purpose: To observe the histopathological changes following irradiation on the wound healing after tooth extraction in the rachitic rats. Materials and Methods: In order to carry out this study, the rats were divided into four groups: Group 1 (normal diet/non-irradiation group), Group 2 (normal diet/irradiation group), Group 3 (rachitogenic diet/non-irradiation group), and Group 4 (rachitogenic diet/irradiation group). Rachitic changes were induced with rachitogenic diet No. 2 (high calcium, low phosphorus, and Vitamin D deficient diet) for 5 weeks. After the extraction of both maxillary first molars of the rats in Group 2 and 4, the head and neck of the rats were irradiated with single absorbed dose of 10 Gy. The rats were sacrificed at the 1st, 5th, 10th, and 15th day after tooth extraction. The specimens including the extraction wound were sectioned, stained with the hematoxylin-eosin and Masson's trichrome method and examined under the light microscope. Results: In the Group 2, the amount of newly formed bone trabeculae on the periphery of extraction socket and osteoblastic activity were reduced. In the Group 3, epithelial fusion was not revealed on the 5th day after toothe extraction and growth rate of osteoid formation was reduced. In the Group 4, necrotized tissue at the outer surface of extraction socket and destructive changes on the alveolar bones were noted on the 10th day. Epithelial fusion was not revealed and large amounts of osteoclast were noted on alveolar bone on the 15th day. Conclusion: The healing process of wound after tooth extraction was retarded by irradiation and especially in the rachitic rats.

• Korean Journal of Medicinal Crop Science
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• v.11 no.1
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• pp.19-23
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• 2003

The optimum extraction condition of pungent component from Zanthoxylum piperitum D.C pericarps by using supercritical fluid extraction(SFE) was investigated. The optimum condition of SFE was $300kg/cm^2$ of pressure, $60\;^{\circ}C$ of extraction temperature, 80% of $CO_2$ fluid, 20% of modifier(methanol) volume and 20 min of extraction time. The extraction efficiency between the classical solvent extraction method and SFE was studied. About 40% of extraction efficiency was improved when SFE was applied.

• Journal of Korea Technical Association of The Pulp and Paper Industry
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• v.45 no.5
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• pp.64-70
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• 2013

In this study, the effect of soxhlet extraction on dewaxing of the aged beeswax-treated paper was examined. To do this, soxhlet extraction of the aged beeswax-treated paper performed with different reflux conditions and then measured the dewaxing efficiency and change in the various properties such as tensile strength, folding endurance, color and brightness. Also, an artificial aging test was executed in order to investigate the effect of soxhlet extraction on the preservability of the dewaxed paper. As the result of FT-IR analysis, a peak area of CH and COOH group, which are main band of beeswax, was decreased or removed after soxhlet extraction. The decreasing rate of each peaks were increased depending on reflux time. After dewaxing, the physical property such as MIT type folding endurance and tensile strength was decreased. And $L^*$ value and brightness were increased while $a^*$ and $b^*$ value were decreased due to the remove of color compounds in beeswax. The more color deviation (${\Delta}E$) is expected with higher reflux times. As the result of artificial aging, preservability of two dewaxed papers except of DP_SE(C) sample was higher than that of untreated paper i.e. beeswax-treated paper.