• 한국자기공명학회논문지
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• 제19권3호
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• pp.137-142
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• 2015

NMR-based structural studies on membrane proteins are appreciated quite challenging due to various reasons, generally including the narrow dispersion of NMR spectra, the severe peak broadening, and the lack of long range NOEs. In spite of the poor biophysical properties, structural studies on membrane proteins have got to go on, considering their functional importance in biological systems. In this review, we provide a simple overview of the techniques generally used in structural studies of membrane proteins by solution NMR, with experimental examples of a helical membrane protein, caveolin 3. Detergent screening is usually employed as the first step and the selection of appropriate detergent is the most important for successful approach to membrane proteins. Various tools can then be applied as specialized NMR techniques in solution that include sample deteuration, amino-acid selective isotope labeling, residual dipolar coupling, and paramagnetic relaxation enhancement.

• Journal of Plant Biotechnology
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• 제42권1호
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• pp.6-12
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• 2015

Medicinal plants resources are becoming important assets since their usages have been expanded to the development of functional foods for human health, more attractive cosmetics, and pharmaceutical industries. However, their phylogenetic origins and names are different from each country and quite often they are mixed each other resulting in the confusion for consumers. In particular, when they are very similar based on their morphological characteristics and distributed as dried roots, it is extremely difficult to differentiate their origins even by specialists. Recently, "DNA barcodes" have been extensively applied to identify their origin of medicinal plant species. In this review, we tried to overview the current research achievements for the development of suitable "DNA barcodes" regarding to the differentiation of medicinal plant species. Furthermore, more advanced techniques including amplification refractory mutation system (ARMS)-PCR, multiplex single base extension (MSBE), high-resolution melting (HRM) curve analyses are also discussed for their practical applications in the authentification of particular medicinal plant species.

• Molecules and Cells
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• 제23권2호
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• pp.132-137
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• 2007

With the advance of stem cell transplantation research, in vivo cell tracking techniques have become increasingly important in recent years. Magnetic resonance imaging (MRI) may provide a unique tool for non-invasive tracking of transplanted cells. Since the initial findings on the stem cell migration by MRI several years ago, there have been numerous studies using various animal models, notably in heart or brain disease models. In order to develop more reliable and clinically applicable methodologies, multiple aspects should be taken into consideration. In this review, we will summarize the current status and future perspectives of in vivo cell tracking technologies using MRI. In particular, use of different MR contrast agents and their detection methods using MRI will be described in much detail. In addition, various cell labeling methods to increase the sensitivity of signals will be extensively discussed. We will also review several key experiments, in which MRI techniques were utilized to detect the presence and/or migration of transplanted stem cells in various animal models. Finally, we will discuss the current problems and future directions of cell tracking methods using MRI.

• 한국정보통신학회논문지
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• 제4권4호
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• pp.739-744
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• 2000

최근 지놈(Genome) 프로젝트를 통해 DNA 염기서열에 대한 정보가 밝혀짐에 따라 분자 수준의 유전자 정보를 다루는 기법이 활발히 연구되고 있다. 그리고 밝혀진 서열정보들의 방대함으로 미루어볼 때 이들 정보를 데이터베이스화하고 효과적인 분석을 행하기 위한 새로운 컴퓨터의 알고리즘의 개발 또한 시급한 일이다. 이러한 측면에서 본 논문에서는 분자생물학에서 매우 중요한 연구 대상으로 삼고있는 프로모터 서열과 유전자간의 연관성으로 발현되는 특징을 알아내기 위한 연관 규칙 탐사 알고리즘을 연구한다. 기존의 탐사 알고리즘은 트랜잭션 데이터를 대상으로 하지만 본 논문에서는 생물학적 데이터를 대상으로 하였기때문에 데이터의형태와 생물학적인 특성을 수용하는 변형된 연관규칙 알고리즘을 설계한다. 본 연구를 통하여 얻어진 결과는 실제 생물학적 실험대상의 후보조합을 최소화 하므로써 많은 시간과 노력 비용을 절감할 수 있다.

• 농업과학연구
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• 제48권3호
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• pp.505-514
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• 2021

Among non-timber forest products, Tricholoma matsutake is a high value added item. Many countries, including Korea, China, and Japan, are doing research and technology development to increase artificial cultivation and productivity. However, the production of T. matsutake is on the decline due to global warming, abnormal temperatures and pine tree pest problems. Therefore, it is necessary to identify trends in domestic and foreign research on T. matsutake, respond to preemptive research and development to preserve the genetic resources of T. matsutake and increase its productivity. Based on the correlation between keywords in the high frequency keywords, it was observed that microbial clusters of T. matsutake are mainly found in Korea. The main focus in China has been the pharmacology studies on the ingredients of T. matsutake. The main focus in Japan has been on preserving the genetic diversity and species of T. matsutake. Thus, future domestic studies of T. matsutake will require pharmacological studies on the ingredients of T. matsutake and on its genetic diversity and species conservation. In addition, unlike China and Japan, genetic keywords did not appear in Korea at high frequency. Therefore, Korea will have to proceed with research using modern molecular biology techniques.

• Corrosion Science and Technology
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• 제23권1호
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• pp.20-32
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• 2024

Metal corrosion in acidic environments is a major issue in various industrial applications. This study evaluates the 4-piperonylideneaminoantipyrine (PPDAA) corrosion inhibition efficiency for mild steel in a hydrochloric acid (HCl) solution. The weight loss method was used to determine the corrosion inhibition efficiency at different concentrations and immersion time periods. Results revealed that the highest inhibition efficiency (94.3%) was achieved at 5 mM concentration after 5 hours of immersion time. To inspect the surface morphology of the inhibitor film on the mild steel surface, scanning electron microscopy (SEM) was used before and after immersion in 1.0 M HCl. Density functional theory (DFT) calculations were performed to investigate the molecular structure and electronic properties of the inhibitor molecule to understand the corrosion inhibition mechanism. Theoretical results showed that the inhibitor molecule can adsorb onto the mild steel surface through its nitrogen and oxygen atoms, forming a protective layer that prevents HCl corrosive attack. These findings highlight the potential of PPDAA as an effective corrosion inhibitor for mild steel in HCl solution. Moreover, combining experimental and theoretical approaches provides insights into the mechanism of corrosion inhibition, which is essential for developing effective strategies to prevent metal corrosion in acidic environments.

• Environmental Analysis Health and Toxicology
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• 제14권1_2호
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• pp.1-12
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• 1999

Recently, several new methods for the detection of genetic damages in vitro and in vivo based on molecular biological techniques were introduced according to the rapid progress in toxicology combined with cellular and molecular biology. Among these methods, mouse lymphoma thymidine kanase (tk) gene forward mutation assay, single cell gel electrophoresis (comet assay) and transgenic animal and cell line model as a target gene of lac I (Big Blue) and lac Z (Muta Mouse) gene mutation are newly introduced based on molecular toxicological approaches. The mouse lymphoma tk$\^$+/-/ gene assay (MOLY) using L5178Y tk$\^$+/-/ mouse lymphoma cell line is one of the mammalian forward mutation assays, and has many advantages and more sensitive than hprt assay. The target gene of MOLY is a heterozygous tk$\^$+/-/ gene located in 11 chromosome, so it is able to detect the wide range of genetic changes like point mutation, deletion, rearrangement, and mitotic recombination within tk gene or deletion of entire chromosome 11. The comet assay is a rapid, simple, visual and sensitive technique for measuring and analysing DNA breakages in mammalian cells, Also, transgenic animal and cell line models, which have exogenous DNA incorporated into their genome, carry recoverable shuttle vector containing reporter genes to assess endogenous effects or alteration in specific genes related to disease process, are powerful tools to study the mechanism of mutation in vivo and in vitro, respectively. Also in vivo acridine orange supravital staining micronucleus assay by using mouse peripheral reticulocytes was introduced as an alternative of bone marrow micronucleus assay. In this respect, there was an International workshop on genotoxicity procedure (IWGTP) supported by OECD and EMS (Environmental Mutagen Society) at Washington D. C. in March 25-26, 1999. The objective of IWGTP is to harmonize the testing procedures internationally, and to extend to finalization of OECD guideline, and to the agreement of new guidelines under the International Conference of Harmonization (ICH) for these methods mentioned above. Therefore, we introduce and review the principle, detailed procedure, and application of MOLY, comet assay, transgenic mutagenesis assay and supravital staining micronucleus assay.

• Applied Biological Chemistry
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• 제50권3호
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• pp.160-166
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• 2007

본 연구는 초미세 분체기술을 이용하여 쌀 전분의 입자구조 파괴가 이루어졌을 때 분자구조적, 물리적 변화가 어떻게 이루어지는지를 구명하고자 하였다. 분쇄 후 쌀 전분의 평균직경은 약 20% 감소가 이루어졌으며 비표면적은 25% 증가하였다. 분쇄 전후의 쌀 전분에 대한 분자량분포를 GPC(gel permeation chromatography)로 측정한 결과 Peak II의 면적이 36.5%에서 59.5%로 상승하였다. 분쇄 전후 손상전분 정도는 각각 16.40%와 99.2%로 나타났다. 분쇄 전에 비하여 분쇄 후 쌀 전분의 물결합능력, 용해도와 광 투과도에서도 월등히 높았다. $30^{\circ}C$에서 20 rpm을 기준으로 분쇄후의 쌀 전분의 겉보기점도는 상대적으로 분쇄 전의 7% 수준에 불과하였으며 측정온도가 높아짐에 따라서 차이는 더욱 커졌다.

• 한국진공학회지
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• 제10권1호
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• pp.22-26
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• 2001

Plasma assisted molecular beam epitaxy(PAMBE)를 사용하여 Si 기판위에 성장시킨 AlN 박막에 대하여 성장온도 및 기판의 방향성에 따른 박막의 결정성 변화를 분석하였다. Reflection high energy electron diffraction(RHEED) 패턴을 이용하여 성장 중의 결정성을 관찰하였고, 성장 후에는 X-ray diffraction(XRD), double crystal X-ray diffraction(DCXD), transmission electron microscopy/diffraction(TEM/TED)분석을 하였다. $850^{\circ}C$이상의 온도에서 Si(100)위에 성장된 AlN박막은 육방정계의 c축 방향으로 우선 배향되어 있음을 확인하였으며 Si(111)위에 성장된 AlN박막의 경우 AlN(0001)/Si(111), AlN(1100)/Si(110), AlN(1120)/Si(112)의 결정방위를 가지고 성장하였음을 확인하였다. 또한 Si(111) 기판 위에서는 전위와 적층결함 등 많은 결정결함에 의해 DCD패턴의 반치폭이 2$\theta$=$36.2^{\circ}$에서 약 3000arcsec에 이르는 등 결정성은 좋지 않았으나 AlN박막이 단결정으로 성장된 것으로 나타났다.

• ALGAE
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• 제33권1호
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• pp.55-68
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• 2018

Foliose species of the Bangiaceae (Porphyra s. l.) are very important in Korean fisheries, and their taxonomy and ecophysiology have received much attention because of the potential for developing or improving aquaculture techniques. Although 20 species of foliose Bangiales have been listed from the Korean coast, some of them remain uncertain and need further comparative morphological studies with molecular comparison. In this study, we confirm the distribution of four Pyropia species from the east coast of Korea, Pyropia kinositae, P. moriensis, P. onoi, and P. retorta sp. nov., based on morphology and rbcL sequence data. Although P. onoi was listed in North Korea in old floral works, its occurrence on the east coast of South Korea is first revealed in this study based on molecular data. P. kinositae and P. moriensis, which were originally described from Hokkaido, Japan, are first reported on the east coast of Korea in this study. Pyropia retorta sp. nov. and P. yezonesis share a similar thallus color and narrow spermatangial patches in the upper portion of the frond, and they have a sympatric distribution. However, P. retorta can be distinguished by the curled or twisted thalli and by molecular data. The biogeographic pattern of the two native species, P. kinositae and P. retorta, suggests that the east coast of Korea may have been a place of refugia during the Last Glacial Maximum (LGM), and then recolonized to the northern part of Japan through the restored East Korean Warm Current after the LGM.