• Journal of Periodontal and Implant Science
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• 제41권2호
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• pp.67-72
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• 2011

Purpose: The aim of this study is to determine whether certain biomaterials have the potential to support cell attachment. After seeding bone marrow stromal cells onto the biomaterials, we investigated their responses to each material in vitro. Methods: Rat bone marrow derived stromal cells were used. The biomaterials were deproteinized bovine bone mineral (DBBM), DBBM coated with fibronectin (FN), synthetic hydroxyapatite (HA), HA coated with FN, HA coated with $\beta$-tricalcium phosphate (TCP), and pure $\beta$-TCP. With confocal laser scanning microscopy, actin filaments and vinculin were observed after 6, 12, and 24 hours of cell seeding. The morphological features of cells on each biomaterial were observed using scanning electron microscopy at day 1 and 7. Results: The cells on HA/FN and HA spread widely and showed better defined actin cytoskeletons than those on the other biomaterials. At the initial phase, FN seemed to have a favorable effect on cell adhesion. In DBBM, very few cells adhered to the surface. Conclusions: Within the limitations of this study, we can conclude that in contrast with DBBM not supporting cell attachment, HA provided a more favorable environment with respect to cell attachment.

• 환경정책연구
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• 제2권2호
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• pp.41-63
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• 2003

CDM(Clean Development Mechanism) project is said to be a mechanism, which profits both the investing country and the host country, while additionally contributing to the reduction of greenhouse gases of the earth as a whole. However in reality, most of the proposed projects do not end up in agreement because of the problems related to differences in recognition between the investing country and the host country of the CDM project. This outlines the background for this research which proposes a new design of institutional arrangements of CDM projects in the Northeast Asian region, mainly Japan, China and Korea. In addition, we investigate the feasibility of the proposed design. The research firstly focuses on the reduction in transaction costs that the participation of Korea will have on a Japan-China CDM project. This paper further emphasizes the potential gains that would materialize if a CDM project involved the whole Northeast Asian region, and not only one country. Our research suggests that an approximate reduction of 23% in transaction costs, and about 4% reduction in the total costs of a CDM project can be expected to follow the Korean participation. In addition to decreasing costs we find that a Korean involvement in a CDM project with Japan will lead to efficiency gains illustrated by a higher increase in the IRR(Internal rate of return) in a Japan-Korea project(11.45% to 12.21%) compared to an IRR incresement of 10.57% to 11.27% for a pure Japanese CDM project. Similar results of a rise in the IRR is found for the whole investment period of 20 years. We can hence conclude that Korean participation in a Japan-China CDM project would improve the implementation possibilities of CDM project in the Northeast Asia region.

• 한국가스학회지
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• 제16권5호
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• pp.41-46
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• 2012

인화점은 공기 속 가연성 증기의 농도가 연소하한계(lower flammability limit)에 도달할 때의 최저 온도이며, 산업현장에서 사용하는 물질들의 화재와 폭발의 위험성을 결정하는 중요한 물성치이다. 단일 성분의 인화점 정보는 여러 문헌에서 얻을 수 있으나, 이성분계 혼합물의 인화점은 충분히 제공되어 있지 않다. 본 연구에서는 tert-pentanol+n-decanel 계의 인화점을 Tag 개방식 장치를 이용하여 측정하였다. 실험값은 Raoult의 법칙과, Wilson 식과 NRTL 식을 활용한 최적화 기법에 의해 계산된 값들과 비교되었다. 최적화 기법에 의한 계산값이 Rauolt의 법칙에 의한 계산값 보다 실험값에 더욱 근접하였다.

• Asian-Australasian Journal of Animal Sciences
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• 제21권12호
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• pp.1710-1720
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• 2008

A comprehensive genome profiling study was undertaken based on automated genotyping and analysis of 20 microsatellite markers that involved 155 birds representing eight different populations. The distribution of microsatellite markers in each of these breeds helped us to decipher genetic heterogeneity, population genetic structure and evolutionary relationships of the present day chicken populations in India. All the microsatellite loci utilized for the analysis were polymorphic and reasonably informative. A total of 285 alleles were documented at 20 loci with a mean of 14.25 alleles/locus. A total of 103 alleles were found to be population/strain specific of which, only 30 per cent had a frequency of more than 10. The mean PIC values ranged from 0.39 for the locus ADL158 to 0.71 for loci MCW005 or ADL267 across the genomes and 0.55 in Dahlem Red to 0.71 in Desi (non-descript), among the populations. The overall mean expected and observed heterozygosity estimates for our populations were 0.68 and 0.64, respectively. The overall mean inbreeding coefficients (FIS) varied between -0.05 (Babcock) and 0.16 (Rhode Island Red). The pairwise FST estimates ranged from 0.06 between Aseel and Desi (non-descript) to 0.14 between Dahlem Red and Babcock. The Nei's genetic distance varied from 0.30 (WLH-IWD and WLH-IWF) to 0.80 (Dahlem Red and Babcock. Phylogenetic analysis grouped all the populations into two main clusters, representing i) the pure breeds, Dahlem Red and Rhode Island Red, and ii) the remaining six populations/strains. All the chicken populations studied were in the state of mild to moderate inbreeding except for commercial birds. A planned breeding is advised for purebreds to revive their genetic potential. High genetic diversity exists in Desi (non-descript), local birds, which can be exploited to genetically improve the birds suitable for backyard poultry.

• The Korean Journal of Physiology and Pharmacology
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• 제22권6호
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• pp.689-696
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• 2018

Increasing evidence implicates changes in $[Ca^{2+}]_i$ and oxidative stress as causative factors in amyloid beta ($A{\beta}$)-induced neuronal cell death. Cyanidin-3-glucoside (C3G), a component of anthocyanin, has been reported to protect against glutamate-induced neuronal cell death by inhibiting $Ca^{2+}$ and $Zn^{2+}$ signaling. The present study aimed to determine whether C3G exerts a protective effect against $A{\beta}_{25-35}$-induced neuronal cell death in cultured rat hippocampal neurons from embryonic day 17 fetal Sprague-Dawley rats using MTT assay for cell survival, and caspase-3 assay and digital imaging methods for $Ca^{2+}$, $Zn^{2+}$, MMP and ROS. Treatment with $A{\beta}_{25-35}$ ($20{\mu}M$) for 48 h induced neuronal cell death in cultured rat pure hippocampal neurons. Treatment with C3G for 48 h significantly increased cell survival. Pretreatment with C3G for 30 min significantly inhibited $A{\beta}_{25-35}$-induced $[Zn^{2+}]_i$ increases as well as $[Ca^{2+}]_i$ increases in the cultured rat hippocampal neurons. C3G also significantly inhibited $A{\beta}_{25-35}$-induced mitochondrial depolarization. C3G also blocked the $A{\beta}_{25-35}$-induced formation of ROS. In addition, C3G significantly inhibited the $A{\beta}_{25-35}$-induced activation of caspase-3. These results suggest that cyanidin-3-glucoside protects against amyloid ${\beta}$-induced neuronal cell death by reducing multiple apoptotic signals.

• Membrane and Water Treatment
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• 제7권5호
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• pp.417-431
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• 2016

Poly(vinylidene fluoride) (PVDF) powder was treated with aqueous sodium hydroxide to obtain partially defluorinated fluoropolymers with expected properties such as improving hydrophilicity and fouling resistance. Raman spectrum and FT-IR results confirmed the existence of conjugated carbon double bonds after alkaline treatment. As the concentration increased, the degree of defluorination increased. The morphology and structure of membranes were examined. The permeation performance was investigated. The results showed that membrane's hydrophilicity increased with increase of the percentage of alkaline treated PVDF powder. Moreover, in terms of the water contact angle, it decreased from $92^{\circ}$ to a minimum of $68^{\circ}$; while water up take increased from 128 to 138%. Fluxof pure water and the cleaning efficiency increased with the increase of alkaline treated PVDF powder. The fouling potential also decreased with the increase of the percentage of alkaline treated PVDF powder. The reason that makes blending PVDF show different characteristics because of partial defluorination, which led the formation of conjugated C = C bonds and the inclusion of oxygen functionalities. The polyene structure followed by hydroxide attack to yield hydroxyl and carbonyl groups. Therefore, the hydrophilicity of blending membrane was improved. The SEM and porosity measurements showed that no obvious variations of the pore dimensions and structures for blend membranes were observed. Mechanical tests suggest that the high content of the alkaline treated PVDF result in membranes with less tolerance of tensile stress and higher brittleness. TGA results exhibited that the blend of alkaline treated PVDF did not change membrane thermal stability.

• Journal of Microbiology and Biotechnology
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• 제26권3호
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• pp.469-476
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• 2016

This study was undertaken to evaluate the immunomodulatory effect of dead nano-sized Lactobacillus plantarum (nLp) in RAW 264.7 cells and murine primary splenocytes. nLp is a dead, shrunken, processed form of L. plantarum nF1 isolated from kimchi (a traditional Korean fermented cabbage) and is less than 1 μm in size. It was found that nLp treatment stimulated nitric oxide (NO) production more in RAW 264.7 macrophages than pure live L. plantarum (pLp), and that the stimulatory properties were probably largely derived from its cell wall. In addition, nLp induced murine splenocyte proliferation more so than pLp; in particular, a high dose of nLp (1.0 × 10¹¹ CFU/ml) stimulated proliferation as much as lipopolysaccharide at 2 μg/ml. Moreover, according to our cytokine profile results in splenocytes, nLp treatment promoted Th1 (TNF-α, IL-12 p70) responses rather than Th2 (IL-4, IL-5) responses and also increased Th17 (IL-6, IL-17A) responses. Thus, nLp stimulated NO release in RAW 264.7 cells and induced splenocyte proliferation more so than pLp and stimulated Th1 and Th17 cytokine production. These findings suggested that dead nLp has potential use as a functional food ingredient to improve the immune response, and especially as a means of inducing Th1/Th17 immune responses.

• Journal of Microbiology and Biotechnology
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• 제20권7호
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• pp.1092-1100
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• 2010

Bacteria, fungi, and protozoa inhabiting the rumen, the largest chamber of the ruminants' stomach, release large quantities of hydrogen during the fermentation of carbohydrates. The hydrogen is used by coexisting methanogens to produce methane in energy-yielding processes. This work shows, for the first time, a fundamental possibility of using a hydrogen-rich fermentation gas produced by selected rumen ciliates to feed a low-temperature hydrogen fuel cell. A biohydrogen fuel cell (BHFC) was constructed consisting of (i) a bioreactor, in which a hydrogen-rich gas was produced from glucose by rumen ciliates, mainly of the Isotrichidae family, deprived of intra- and extracellular bacteria, methanogens, and fungi; and (ii) a chemical fuel cell of the polymer-electrolyte type (PEFC). The fuel cell was used as a tester of the technical applicability of the fermentation gas produced by the rumen ciliates for power generation. The average estimated hydrogen yield was ca. 1.15 mol $H_2$ per mole of fermented glucose. The BHFC performance was equal to the performance of the PEFC running on pure hydrogen. No fuel cell poisoning effects were detected. A maximum power density of $1.66\;kW/m^2$ (PEFC geometric area) was obtained at room temperature. The maximum volumetric power density was $128\;W/m^3$ but the coulombic efficiency was only ca. 3.8%. The configuration of the bioreactor limited the continuous operation time of this BHFC to ca. 14 h.

• Korean Chemical Engineering Research
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• 제53권6호
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• pp.695-702
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• 2015

Liquid-liquid extraction (LLE) using various solvents was studied for recovery of acetic acid from a synthetic ethanol fermentation broth. The microbial fermentation of sugars presented in hydrolyzate gives rise to acetic acid as a byproduct. In order to obtain pure ethanol for use as a biofuel, fermentation broth should be subjected to acetic acid removal step and the recovered acetic acid can be put to industrial use. Herein, batch LLE experiments were carried out at $25^{\circ}C$ using a synthetic fermentation broth comprising $20.0g\;l^{-1}$ acetic acid and $5.0g\;l^{-1}$ ethanol. Ethyl acetate (EtOAc), tri-n-octylphosphine oxide (TOPO), tri-n-octylamine (TOA), and tri-n-alkylphosphine oxide (TAPO) were utilized as solvents, and the extraction potential of each solvent was evaluated by varying the organic phase-to-aqueous phase ratios as 0.2, 0.5, 1.0, 2.0, and 4.0. The highest acetic acid extraction yield was achieved with TAPO; however, the lowest ethanol-to-acetic acid extraction ratio was obtained using TOPO. In a single-stage batch extraction, 97.0 % and 92.4 % of acetic acid could be extracted using TAPO and TOPO when the ratio of organic-to-aqueous phases is 4:1 respectively. A higher solvent-to-feed ratio resulted in an increase in the ethanol-to-acetic acid ratio, which decreased both acetic acid purity and acetic acid extraction yield.

• 설비공학논문집
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• 제22권6호
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• pp.383-391
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• 2010

In this study, HFC152a, HFC134a/HFC152a and HC290/HFC134a/HFC152a mixtures are studied for the supplementary and alternative refrigerants for HFC134a used in automobile air-conditioners. Due to the high global warming potential of HFC134a, it has to be phased out in the long run. Thermodynamic performance of these refrigerants are measured in a bench tester of 3.5 kW capacity with an open type compressor under both summer and winter conditions. Test results show that the coefficient of performance (COP) and capacity of pure HFC152a and HFC134a/HFC152a mixture are 9.1~12% and 7% higher than those of HFC134a. As for the HC290/HFC134a/HFC152a, the COP is up to 9.5% higher than that of HFC134a with 1~2% of HC290 while that is up to 6.1% lower than that of HFC134a with 5% HC290. The capacity of the ternary mixture, however, is 8.6% higher than that of HFC134a at all compositions tested. The compressor discharge temperatures of all refrigerants tested are $6{\sim}10^{\circ}C$ higher than that of HFC134a. For all refrigerants, the amount of charge is reduced up to 32% due to the decrease in liquid density. Overall, these refrigerants provide good performance with reasonable energy savings with less environmental problem and thus can be used as long term alternatives for automobile air-conditioners.