• 천문학회보
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• 제39권1호
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• pp.57.1-57.1
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• 2014

We present the preliminary results of CO outflow survey toward the 56 Very Low Luminosity Object (VeLLO) candidates at CO J=2-1 and J=3-2 transitions with two radio telescopes of the Caltech Submillimeter Observatory (CSO) and the Atacama Submillimeter Telescope Experiment (ASTE). The survey is aimed to understand the origin of the formation of low-mass stars or substellar objects. The VeLLO is a very faint (${\leq}0.1$ $L_{\odot}$) object deeply embedded in dense molecular clouds and believed to be a proto-brown dwarf which will be a brown dwarf or a faint protostar which has just formed with little mass accretion or which is in quiescent stage of episodic accretion. The candidates were searched for over all nearby ($d{\leq}450$ pc) Gould belt clouds and listed in a new catalogue of the VeLLO candidates by Kim et al. (2014 submitted). To diagnose present status and future fate of the VeLLOs, we conducted a systematic observation for the CO molecular outflows of the 56 VeLLOs to infer how accretion is being made around the VeLLOs. We found 17 VeLLO candidates either having a prominent wing in line profiles or showing bipolar intensity distribution of high velocity components. We will discuss the physical properties of these CO outflows and the identity of the VeLLO candidates.

• Elastomers and Composites
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• 제48권1호
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• pp.85-91
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• 2013

본 연구에서는 메탈로센 촉매, 공촉매 시스템을 이용한 에틸렌, 1-헥센, 스티렌계 단량체가 포함된 삼원공중합체를 합성하였다. 본 연구에서 비교 및 분석을 위하여 사용한 스티렌계 단량체들로는 스티렌, p-methylstyrene, 4-tert-butylstyrene 이다. $^{13}C$ NMR과 $^1H$ NMR을 이용하여 삼원공중합체의 구조를 분석하였고 조성을 확인하였다. 삼원공중합체의 촉매활성도, 수율, 분자량을 비교하였고 삼원공중합체에 삽입된 스티렌계 단량체에 따른 유리전이온도, 결정화도 및 열적특성을 DMA, WAXS 및 TGA 등을 이용하여 분석하였다.

• Biotechnology and Bioprocess Engineering:BBE
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• 제3권1호
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• pp.35-39
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• 1998

An enzymatic process was developed to produce protein hydrolysater form defatted soya protein. Various unit operations were tried, and the effects of pre- and post-treatments on the product characteristics such as degree of hydroylsis (DH), free amino acid content (%FAA) and average molecular weight (MW) were investigated. The use of acid washes showed no difference in %DH. Increasing pH during pre-cooking gave lower %DH. Alkaline cooking made too much insoluble protein, thus the protein yield was too small. A better hydrolysis with more acceptable taste was obtained when the combination of Neutrase/Alcalase/Flavourzyme was used in place of Alcalase/Flavourzyme combination; Untoasted defatted soya was more effective on the proteolysis than toasted one. The MW of the evaporated and spray dried product was higher than that of undried product, due to precipitation of low-solubility components. When ultrafiltration and the product concentration carried out the product separation by reverse osmosis, the solubility and the taste of the product were improved. The difference between enzyme hydrolysate and acid hydrolysate was significant in free amino acid composition, especially in tyrosine, phenylalanine, glutamine and asparagine.

• Journal of Microbiology and Biotechnology
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• 제5권4호
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• pp.200-205
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• 1995

Nutritional factors regulating the morphological differentiation and physiological differentiation of Streptomyces exfoliatus SMF13 on surface cultures were evaluated. S. exfoliatus SMF13 produced leupeptin and chymotrypsin-like protease (CTP) at the stage of substrate mycelium growth, and leupeptin-inactivating enzyme (LIE) and trypsin-like protease (TLP) at the stage of aerial mycelium growth. The activity of leupeptin and CTP was high in the region of active growing substrate mycelium, whereas the activity of LIE and TLP was high in the region of aerial mycelium or spores. The differentiations were induced in glucose-limited conditions or by the addition of glucose anti-metabolite (methyl $\alpha$-glucopyranoside), but repressed by high concentrations of glucose or casamino acids. Morphological differentiation (formation of aerial mycelia and spores) was closely related with physiological differentiation (formation of brown-pigment, LIE and TLP). The local distribution of leupeptin, CTP, LIE, and TLP in a developing colony showed that colony development correlated with the production and functions of the compounds: CTP is essential for providing a nitrogen source for mycelium growth: leupeptin regulates TLP activity: LIE inactivates leupeptin: TLP hydrolyzes nongrowing mycelium.

• Journal of Microbiology and Biotechnology
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• 제18권7호
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• pp.1207-1215
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• 2008

To investigate the occurrence and species diversity of mycobacteria in waters, surface water samples were collected monthly from the Han River and tap water samples at the terminal sites of the distribution system. Mycobacteria in each water sample were isolated by decontamination using cetylpyridinium chloride (CPC) and cultivation on Middlebrook 7H10 agar, and then identified by polymerase chain reaction-restriction fragment length polymorphism analysis (PRA) and sequencing of the 65-kDa heat-shock protein gene (hsp65 gene). Mycobacteria were detected in 59% of the surface water samples and 26% of the tap water samples. Over half of the 158 isolates could not be identified by hsp65 PRA and gene sequencing, and several identification discrepancies were observed between the two methods. The most frequently isolated species was Mycobacterium gordonae in surface water and M. lentiflavum in tap water. M. avium complex (MAC), the most important pathogen among environmental mycobacteria, was detected in the surface water samples but not found in the tap water samples. The result demonstrated that water is an important environmental source of mycobacteria and the combined application of hsp65 PRA and sequencing was more reliable than hsp65 PRA alone to accurately identify mycobacteria present in water.

• 환경생물
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• 제32권1호
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• pp.88-94
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• 2014

종의 장거리 산포는 집단의 확산과 집단간 개체의 흐름에 중요한 역할을 한다. 본 연구는 독도에서 발견된 식물을 형태학적 특징과 핵 및 엽록체 DNA의 분자마커를 이용하여 종을 식별한 결과, 참빗살나무 (노박덩굴과)로 확인되었다. 얕은 토양층과 험준한 지형 등 입지적으로 열악한 대양섬인 독도에서 목본의 분포는 의미있는 결과이며, 향후 외부유입종의 지속적인 모니터링이 요구된다.

• Journal of Preventive Medicine and Public Health
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• 제42권6호
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• pp.371-376
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• 2009

In this article, we reviewed the literature on risk assessment (RA) models with and without molecular genomic markers and the current utility of the markers in the pharmacogenetic field. Epidemiological risk assessment is applied using statistical models and equations established from current scientific knowledge of risk and disease. Several papers have reported that traditional RA tools have significant limitations in decision-making in management strategies for individuals as predictions of diseases and disease progression are inaccurate. Recently, the model added information on the genetic susceptibility factors that are expected to be most responsible for differences in individual risk. On the continuum of health care, from diagnosis to treatment, pharmacogenetics has been developed based on the accumulated knowledge of human genomic variation involving drug distribution and metabolism and the target of action, which has the potential to facilitate personalized medicine that can avoid therapeutic failure and serious side effects. There are many challenges for the applicability of genomic information in a clinical setting. Current uses of genetic markers for managing drug therapy and issues in the development of a valid biomarker in pharmacogenetics are discussed.

• Molecules and Cells
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• 제21권1호
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• pp.89-103
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• 2006

Population structure was investigated in Reticulitermes speratus populations in the Korean Peninsula and the Japanese Archipelago. All trees derived from analyses of the combined sequence dataset of two mitochondrial genes, COII and COIII, showed that R. speratus populations cluster into two major clades comprising the Korean/southern Japanese populations and the northern Japanese populations. Analysis of population genetic structure showed strong genetic partitioning between populations of the two clades. To understand historical migration routes and current distributions, the phylogeographic history of R. speratus was inferred from intra-/interspecific phylogeny and divergence times estimated between the clades of the phylogenetic tree. The estimated migration route and divergence time of ancestral R. speratus are congruent with recent paleogeographic hypotheses involving land-bridge connections between the Asian continent and the Japanese Archipelago. We suggest that ancestral R. speratus separated into northern and southern Japanese populations after its migration into the Japanese main islands from East China during the early Pleistocene via the East China Sea basin, which may have been exposed during that period. The Korean populations seem to have diverged recently from southern Japanese populations; this may explain the current distribution of R. speratus in the Japanese Arachipelago, and account for why it is restricted to northern areas of the Tokara Strait.

• Bulletin of the Korean Chemical Society
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• 제17권8호
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• pp.735-744
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• 1996

We present results of molecular dynamic (MD) simulations for the thermodynamic and structural properties of liquid n-alkanes, from n-butane to n-heptadecane, using three different models Ⅰ-Ⅲ. Two of the three classes of models are collapsed atomic models while the third class is an atomistically detailed model. Model Ⅰ is the original Ryckaert and Bellemans' collapsed atomic model [Discuss. Faraday Soc. 1978, 66, 95] and model Ⅱ is the expanded collapsed model which includes C-C bond stretching and C-C-C bond angle bending potentials in addition to Lennard-Jones and torsional potentials of model Ⅰ. In model Ⅲ all the carbon and hydrogen atoms in the monomeric units are represented explicitly for the alkane molecules. Excellent agreement of the results of our MD simulations of model Ⅰ for n-butane with those of Edberg et al.[J. Chem. Phys. 1986, 84, 6933], who used a different algorithm confirms the validity of our algorithms for MD simulations of model Ⅱ for 14 liquid n-alkanes and of models Ⅰ and Ⅲ for liquid n-butane, n-decane, and n-heptadecane. The thermodynamic and structural properties of models Ⅰ and Ⅱ are very similar to each other and the thermodynamic properties of model Ⅲ for the three n-alkanes are not much different from those of models Ⅰ and Ⅱ. However, the structural properties of model Ⅲ are very different from those of models Ⅰ and Ⅱ as observed by comparing the radial distribution functions, the average end-to-end distances and the root-mean-squared radii of gyrations.

• Bulletin of the Korean Chemical Society
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• 제20권8호
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• pp.897-904
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• 1999

We have presented the thermodynamic, structural and dynamic properties of liquid pentane isomers - normal pentane, isopentane, and neopentane - using an expanded collapsed atomic model. The thermodynamic properties show that the intermolecular interactions become weaker as the molecular shape becomes more nearly spherical and the surface area decreases with branching. The structural properties are well predicted from the site-site radial, the average end-to-end distance, and the root-mean-squared radius of gyration distribution func-tions. The dynamic properties are obtained from the time correlation functions - the mean square displacement (MSD), the velocity auto-correlation (VAC), the cosine (CAC), the stress (SAC), the pressure (PAC), and the heat flux auto-correlation (HFAC) functions - of liquid pentane isomers. Two self-diffusion coefficients of liquid pentane isomers calculated from the MSD's via the Einstein equation and the VAC's via the Green-Kubo relation show the same trend but do not coincide with the branching effect on self-diffusion. The rotational re-laxation time of liquid pentane isomers obtained from the CAC's decreases monotonously as branching increases. Two kinds of viscosities of liquid pentane isomers calculated from the SAC and PAC functions via the Green-Kubo relation have the same trend compared with the experimental results. The thermal conductivity calculated from the HFAC increases as branching increases.