• Journal of Microbiology and Biotechnology
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• v.32 no.4
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• pp.531-540
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• 2022

Due to the high incidence of malignant melanoma, the establishment of in vitro models that recapitulate the tumor microenvironment is of great biological and clinical importance for tumor treatment and drug research. In this study, 3D printing technology was used to prepare GelMA/PEGDA composite scaffolds that mimic the microenvironment of human malignant melanoma cell (A375) growth and construct in vitro melanoma micro-models. The GelMA/PEGDA hybrid scaffold was tested by the mechanical property, cell live/dead assay, cell proliferation assay, cytoskeleton staining and drug loading assay. The growth of tumor cells in two- and three-dimensional culture systems and the anti-cancer effect of luteolin were evaluated using the live/dead staining method and the Cell Counting Kit-8 (CCK-8) method. The results showed a high aggregation of tumor cells on the 3D scaffold, which was suitable for long-term culture. Cytoskeleton staining and immunofluorescent protein staining were used to evaluate the degree of differentiation of tumor cells under 2D and 3D culture systems. The results indicated that 3D bioprinted scaffolds were more suitable for tumor cell expansion and differentiation, and the tumor cells were more aggressive. In addition, luteolin was time- and dose-dependent on tumor cells, and tumor cells in the 3D culture system were more resistant to the drug.

• Journal of Korean Society for Quality Management
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• v.43 no.1
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• pp.31-42
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• 2015

Purpose: System consists of a lot of units with coherent function. In design phase, various units could be considered with the same function. In this study, we consider the alternative units with the same function and redundancy allocation to maximize system reliability in multi level system. Methods: The redundancy allocation problem with the alternative units in multi level system is formulated. Memetic algorithm(MA) is proposed to optimize the redundancy allocation problem. In addition, the performance of the proposed algorithm is explained by a numerical experiment. Results: MA showed better results than genetic algorithm(GA) and the convergence of the solutions in MA was also faster than GA. In addition, we could know from experiment that system reliability is increased and the chosen unit for redundancy allocation is changed if cost limit is increased. Conclusion: The chose unit for redundancy allocation is changed as resource constraints. It means we need to consider the alternative units in system design. In the future, we need to consider various problem related to redundancy allocation in multi level system and develop the better method to enhance search performance.

• Macromolecular Research
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• v.15 no.6
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• pp.541-546
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• 2007

The combination of atom transfer radical polymerization (ATRP) and click chemistry was employed for the efficient preparation of well-defined block copolymers. Bromo terminated poly(methyl acrylate) (pMA-Br) was prepared by an ATRP initiator, ethyl-2-bromoisobutyrate (EBiB). Subsequently, the bromine chain end of pMA-Br was converted to an azide group by simple nucleophilic substitution reaction. ${\alpha}-Alkyn-{\omega}-bromo-functionalized$ polystyrene was also synthesized by ATRP using the alkyn-functionalized initiator, propargyl-2-bromoisobutyrate (PgBiB). In both cases, the conversion was limited to a low level to ensure a high degree of chain end functionality. Then the coupling reaction between the azide end group in $pMA-N_3$ and alkyn-functionalized PgBiB-pSt was performed by Cu(I)catalysis. This coupling reaction was monitored by gel permeation chromatography (GPC). The synthesized block copolymer was characterized by FT-IR, $^1H-NMR$ spectroscopy and $^1H-^1H$ COSY correlation spectroscopy.

• YAKHAK HOEJI
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• v.47 no.3
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• pp.142-147
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• 2003

Gas chromatography-mass spectrometric (GC-MS) procedure is presented for the simultaneous qualification and quantitation of methamphetamine (MA), amphetamine (AMP), 3,4-methylenedioxymethamphetamine (MDMA), 3,4-methylenedioxyamphetamine (MDA), and 3,4-methylenedioxyethylamphetamine (MDEA) in human hair. The method procedure involves decontamination of hair with distilled water and acetone, acidic hydrolysis, extraction in the presence of deuterated internal standards, and GC-MS analysis after derivatization with trifluoroacetic anhydride (TFAA) in ethylacetate. The limit of detection for 5 drugs were about 0.1∼0.15 ng/mg using 30 mg hair sample. Coefficient variations of correlation ranged from 0.9941 to 0.9993. The recoveries of these drugs were found to be 93.4∼104.4％. The concentrations of AMP, MA, MDA, and MDMA in abusers' hair samples were measured 0.17∼2.88, 2.09∼18.34, 0.24∼3.83, and 3.10∼22.81 ng/mg, respectively. The ratios of MA/AMP and MDMA/MDA ranged 5.67∼49.57 and 4.78∼54.31, respectively. This assay has been successfully utilized in the evaluation of the deposition of amphetamine-type stimulants (ATS) in human hair.

• Journal of Communications and Networks
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• v.9 no.2
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• pp.112-117
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• 2007

In this paper, we focus on the total transmission power minimization problem for downlink beamforming multiple-input multiple-output (MIMO) orthogonal frequency division multiplexing (OFDM) systems while ensuring each user's QoS requirement. Although the linear integer programming (LIP) solution we formulate provides the performance upper bound of the margin adaptive (MA) optimization problem, it is hard to be implemented in practice due to its high computational complexity. By regarding each user's equivalent channel gain as approximate independent values and using iterative descent method, we present a heuristic MA resource allocation algorithm. Simulation results show that the proposed algorithm efficiently converges to the local optimum, which is very close to the performance of the optimal LIP solution. Compared with existing space division multiple access (SDMA) OFDM systems with or without adaptive resource allocation, the proposed algorithm achieves significant performance improvement by exploiting the frequency diversity and multi-user diversity in downlink multiple-input single-output (MISO) OFDM systems.

• Journal of Sasang Constitutional Medicine
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• v.32 no.3
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• pp.1-7
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• 2020

Objective The purpose of this study was to understand the conclusion of 「Gwangjeseol」 in 『Dongeuisusebowon』 in a more accurate sense. Method We examined the basic viewpoint of Lee je-ma in 「Seongmyeonglon」 in 『Dongeuisusebowon』. Based on the interpretation of the 「Seongmyeonglon」, the viewpoints described in the pathology theory of 『Dongeuisusebowon』 were examined. In addition to 『Dongeuisusebowon』, we looked for contents related to "TuHyeonJilNeung" and "HoHyeonNagSeon" in Lee je-ma's book 『Gyukchigo』 and 『Dongmuyugo』. Result We have found that the meanings of the words "TuHyeonJilNeung" and "HoHyeonNagSeon" in the last article of 「Gwangjeseol」 are not limited to just the 「Gwangjeseol」, but contain the meaning of a topic that runs through the entire book. According to the 『Gyukchigo』 and 『Dongmuyugo』, the meaning of "TuHyeonJilNeung" is related to the "Sa-Bang-Il-Yog", and the "Sa-Bang-Il-Yog" is the "ilsimjiyog" that prevents the practice of "Ji-Haeng". This concept is the same as the concept of "Ji-Haeng" in 「Seongmyeonglon」, the first unit of 『Dongeuisusebowon』. Conclusion It is considered that Lee je-ma wanted to emphasize the reason and mindset to do "Ji-Haeng" by writing the end of the 「Gwangjeseol」, which is the last part of 『Dongeuisusebowon』.

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.15 no.2
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• pp.442-460
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• 2021

Nowadays, recommendation systems (RSs) are applied to all aspects of online life. In order to overcome the problem that individuals who do not meet the constraints need to be regenerated when the many-objective evolutionary algorithm (MaOEA) solves the hybrid recommendation model, this paper proposes a many-objective particle swarm optimization algorithm based on multiple criteria (MaPSO-MC). A generation-based fitness evaluation strategy with diversity enhancement (GBFE-DE) and ISDE⁺ are coupled to comprehensively evaluate individual performance. At the same time, according to the characteristics of the model, the regional optimization has an impact on the individual update, and a many-objective evolutionary strategy based on bacterial foraging (MaBF) is used to improve the algorithm search speed. Experimental results prove that this algorithm has excellent convergence and diversity, and can produce accurate, diverse, novel and high coverage recommendations when solving recommendation models.

• Korean Journal of Poultry Science
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• v.41 no.1
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• pp.21-27
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• 2014

To preserve chicken genetic materials like cryopreserved spermatozoa, various kinds of freezing agents like glycerol, dimethylsuloxide, dimethylformamide or dimethylacetamide have been used for rooster semen preparation. Recently, the usage of N-methylacetamide (MA) for Ogye rooster semen preservation resulted in hatched chicken successfully. In this study, we investigated the effects of 7, 9 and 11% of MA on the viability, fertility and hatchability of frozen-thawed rooster semen using artificial insemination. The results of viability, fertility and hatchability in frozen semen with 7%, 9% or 11% MA were $35.16{\pm}6.12%$, $67.83{\pm}15.3%$ and $66.2{\pm}16.3%$ of motile sperm rate, 21.5%, 34.7% and 25% of fertility rate, and 100%, 89.5% and 87.5% of hatchability rate. The results of control group with frozen semen were 96.0% of fertility rate and 92.2% of hatchability rate. With these results, the concentration range of MA as a freezing agent of rooster semen could be 7~9% of media. The higher concentration of 9 % MA could decrease the fertility rate of thawed semen not the rate of hatchability rate. So the use of MA without affecting fertility rate would be a key point of freezing method of rooster semen for poultry genetic resource preservation.

• Communications of the Korean Mathematical Society
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• v.11 no.2
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• pp.495-501
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• 1996

There is currently a regain of interest in ADI (Alternating Direction Implicit) method as a preconditioner for iterative Method for solving large sparse linear systems, because of its suitability for parallel computation. However the classical ADI is not applicable to FE(Finite Element) matrices. In this paper wer propose a Block-ADI method, which is applicable to Finite Element metrices. The new approach is a combination of classical ADI method and domain decompositi on. Also, we provide a partial proof of the convergence based on the results from the regular splittings, in case the discretization metrix is symmetric positive definite.

• The Korean Journal of Applied Statistics
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• v.21 no.1
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• pp.65-80
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• 2008

Small scale time-course microarray experiments are those which have a small number of time points. They comprise about 80 percent of all time-course microarray experiments conducted up to 2005. Several statistical methods for the small scale time-course microarray experiments have been proposed. In this paper we applied three methods, namely, QR method, maSigPro method and STEM, to a real time-course microarray experiment which had six time points. We compared the performance of these three methods based on a simulation study and concluded that STEM outperformed, in general, in terms of power when the FDR was set to be 5%.