• Journal of Microbiology and Biotechnology
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• v.27 no.10
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• pp.1798-1807
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• 2017

The differentiations in nitrogen-converting activity and microbial community structure between granular size fractions in a continuous completely autotrophic nitrogen removal over nitrite (CANON) reactor, having a superior specific nitrogen removal rate of $0.24g/(g\;VSS{\cdot}h)$, were investigated by batch tests and high-throughput pyrosequencing analysis, respectively. Results revealed that a high dissolved oxygen concentration (>1.8 mg/l) could result in efficient nitrite accumulation with small granules (0.2-0.6 mm in diameter), because aerobic ammonium-oxidizing bacteria (genus Nitrosomonas) predominated therein. Meanwhile, intermediate size granules (1.4-2.0 mm in diameter) showed the highest nitrogen removal activity of $40.4mg/(g\;VSS{\cdot}h)$ under sufficient oxygen supply, corresponding to the relative abundance ratio of aerobic to anaerobic ammonium-oxidizing bacteria (genus Candidatus Kuenenia) of 5.7. Additionally, a dual substrate competition for oxygen and nitrite would be considered as the main mechanism for repression of nitrite-oxidizing bacteria, and the few Nitrospira spp. did not remarkably affect the overall performance of the reactor. Because all the granular size fractions could accomplish the CANON process independently under oxygen limiting conditions, maintaining a diversity of granular size would facilitate the stability of the suspended growth CANON system.

• Korean Journal of Agricultural Science
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• v.20 no.2
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• pp.189-200
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• 1993

Ornithine decarboxylase is the first and rate limiting enzyme in the biosynthesis of polyamines in mammalian cells. During cell growth the enzyme is regulated by rapid changes in the level of its mRNA and protein. To explore the molecular basis of these changes, ODC-specific complementary DNA (cDNA) clones were isolated from a bovine cDNA library. This region of the cDNA contained a portion of the open reading frame, a 3'noncoding region, and a poly-A tail of 456, 348, and 14 nucleotides, respectively. A comparison of the deduced sequence of the carboxyl terminal 151 amino acids of ODC with amino acid sequences in the same region of the enzyme from human, mouse, rat, and hamster showed greater than 88% identity in these proteins. The highly conserved nature of the amino acid sequences may be related to the important role of ODC in cell growth and differentiation.

• Microbiology and Biotechnology Letters
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• v.43 no.1
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• pp.22-30
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• 2015

CSF is a major concern for the swine industry, representing currently the most epizootically dangerous disease to the species. Numerous CSFV isolates with various degrees of virulence have already been isolated worldwide, ranging from low virulent strains that do not result in any apparent clinical signs to highly virulent strains that cause a severe per acute hemorrhagic fever with very high mortality. The molecular epidemiology of CSFVs has proven to be an essential tool for effective disease control and the development of safe and effective vaccines. Therefore, this study cloned and sequenced local CSFV isolates, and conducted a phylogenetic analysis based on the E2 glycoprotein encoding sequences.The RNA was extracted from PK15 cell culture passaged CSFV isolates, the cDNA prepared, and the complete E2 gene amplified with a product size of 1186 bp. The gelpurified PCR product was cloned into a pGEMT easy vector and the positive clone commercially sequenced. Aligning the nucleotide (1119 bp) and amino acid (373) sequences with 29 reference strains revealed nucleotide and amino acid sequence identities of 82.60-97.80% and 88.70-98.70%, respectively, indicating a higher mutation rate of the field CSFV strains. The phylogenetic analysis based on the complete E2 amino acid sequences also revealed a reliable differentiation of all the analyzed strains into specific genetic groups and subgroups, plus the local isolate (CSFV-E2) was found to cluster with the CSFV subgroup 2.2. Thus, the full-length E2 cds proved to be most suitable for a reliable and statistically significant phylogenetic analysis of CSFV isolates.

• Korean Business Review
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• v.6
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• pp.135-152
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• 1993

The optional market segmentation pricing policy for rooms of hotels are investigated under the assumption of a linear demand function, and for four different situations: (1) single price market, (2) optimal segmentation of the unused capacity of a single-price-maeket, (3) optimal segmantation for all rooms, and (4) opimal segmentation for infiltration from higher priced to adjacent lower priced segments. The purpose of tis study is th show that with proper pricing policy, it would be possible to increase profits considerably. Such a profit increase might be achived by market segmentation coupled with product differentiation, where the different market segments are identified, sperated, and in each segment a different price per room is called for. The different prices are determined based on the specific price elasticity typical for each market segment and the relavant costs. The pricing model implied in this study is based on basic economic pricing theory and optimization techniques. While somewhat complex in its mathmatical solution, it can be easily programmed for use by practitioners, avoiding the need to cope with the technical aspects of the solution. In section II-1, the optimal single-market Single-price policy is evaluated. The optimal strategy under the constraint that only the previously unutilized rooms are segmented is analysed in section II-2, while the optimal strategy without this constraint is determined in section II-3. In section II-4, the optimal market-segmentation pricing policy is derived for the case in which market seperation is allowed for all the rooms under the assumption of custtomer infiltration from each market segment to the adjacent lower priced segment Finally, some considerations relating to the practicality of the model as a decision support tool and the requirements for its implementation are discussed in section III.

• Development and Reproduction
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• v.14 no.3
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• pp.155-162
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• 2010

The trophectoderm is one of the earliest cell types to differentiate in the forming placenta. It is an important for the initial implantation and placentation during pregnancy. Trophoblast stem cells (TBSCs) develop from the blastocyst and are maintained by signals emanating from the inner cell mass. However, several limitations including rarity and difficulty in isolation of trophoblast stem cells derived from blastocyst still exist. To establish a model for trophoblast differentiation, we isolated TBSCs from human term placenta ($\geq$38 weeks) and characterized. Cell cycle was analyzed by measuring DNA content by FACS analysis and phenotype of TBSCs was characterized by RT-PCR and FACS analysis. TBSCs have expressed various markers such as self-renewal markers (Nanog, Sox2), three germ layer markers (hNF68, alpha-cardiac actin, hAFP), trophoblast specific markers (CDX-2, CK7, HLA-G), and TERT gene. In FACS analysis, TBSCs isolated from term placenta showed that the majority of cells expressed CD13, CD44, CD90, CD95, CD105, HLA-ABC, cytokeratin 7, and HLA-G. Testing for CD31, CD34, CD45, CD71, vimentin and HLA-DR were negative. TBSCs were shown to decrease the growth rate when cultured in conditioned medium without FGF4/heparin as well as the morphology was changed to a characteristic giant cell with a large cytoplasm and nucleus. In invasion assay, TBSCs isolated from term placenta showed invasion activities in in vivo using nude mice and in vitro Matrigel system. Taken together, these results support that an isolation potential of TBSCs from term placenta as well as a good source for understanding of the infertility mechanism.

• Journal of Animal Reproduction and Biotechnology
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• v.36 no.4
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• pp.203-211
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• 2021

Diabetic mellitus (DM) is a carbohydrate metabolic disorder that involves high blood sugar because insulin works abnormally. Type 2 diabetes accounts for most of them. However, diabetes treatments such as GLP-1 and DPP-4 inhibitors commonly caused side effects including gastrointestinal disorders. Grifola frondosa (G. frondosa) revealed various pharmacological effects in recent studies. It has a variety of anti-cancer polysaccharides through host-mediated mechanisms. D-fraction in G. frondosa has apoptotic effects, promoting myeloid cell proliferation and differentiation into granulocytes-macrophages. It has also been shown to reduce the survival rate of breast cancer cells. Though, no further study has been conducted on the specific effects of G. frondosa in the db/db mouse. Therefore, we would like to research the blood glucose improving effect of G. frondosa, a natural material, in type 2 diabetes model mouse, in this study. G. frondosa was administered to the disease model mouse (BKS.Cg-+Lepr^db/+Lepr^db/OlaHsd) for 8 weeks to monitor weight and blood glucose changes every week. And we evaluated anti-diabetes effects by checking biomarker changes shown through blood. Experiment did not show statistically significant weight differences, but control groups showed significantly higher weight gain than G. frondosa administered groups. We collected blood from the tail veins of the db/db mouse each week. As a result, the lowest blood sugar level was shown in the 500 mg/kg group of G. frondosa. Glucose in the blood was examined with HBA1c, and 7.8% was shown in the 500 mg/kg administration group, lower than in other groups. These results suggest the potential improvements of diabetes in G. frondosa.

• Journal of Global Scholars of Marketing Science
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• v.17 no.3
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• pp.39-59
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• 2007

The international involvement of a firm has been described as a gradual development process "a process in which the enterprise gradually increases its international involvement in many studies. This process evolves in the interplay between the development of knowledge about foreign markets and operations on one hand and increasing commitment of resources to foreign markets on the other." On the basis of Uppsala internationalization model, many studies strengthen strong theoretical and empirical support. According to the predictions of the classic stages theory, the internationalization process of firms have been recognized and characterized gradual evolution to foreign markets, so called stage theory: indirect & direct export, strategic alliance and foreign direct investment. However, termed "international new ventures" (McDougall, Shane, and Oviatt 1994), "born globals" (Knight 1997; Knight and Cavusgil 1996; Madsen and Servais 1997), "instant internationals" (Preece, Miles, and Baetz 1999), or "global startups" (Oviatt and McDougall 1994) have been used and come into spotlight in internationalization study of technology intensity venture companies. Recent researches focused on venture company have suggested the phenomenons of 'born global' firms as a contradiction to the stages theory. Especially the article by Oviatt and McDougall threw the spotlight on international entrepreneurs, on international new ventures, and on their importance in the globalising world economy. Since venture companies have, by definition. lack of economies of scale, lack of resources (financial and knowledge), and aversion to risk taking, they have a difficulty in expanding their market to abroad and pursue internalization gradually and step by step. However many venture companies have pursued 'Born Global Strategy', which is different from process strategy, because corporate's environment has been rapidly changing to globalization. The existing studies investigate that (1) why the ventures enter into overseas market in those early stage, even in infancy, (2) what make the different international strategy among ventures and the born global strategy is better to the infant ventures. However, as for venture's performance(growth and profitability), the existing results do not correspond each other. They also, don't include marketing strategy (differentiation, low price, market breadth and market pioneer) that is important factors in studying of BGV's performance. In this paper I aim to delineate the appearance of international new ventures and the phenomenons of venture companies' internationalization strategy. In order to verify research problems, I develop a resource-based model and marketing strategies for analyzing the effects of the born global venture firms. In this paper, I suggested 3 research problems. First, do the korean venture companies take some advantages in the aspects of corporate's performances (growth, profitability and overall market performances) when they pursue internationalization from inception? Second, do the korean BGV have firm specific assets (foreign experiences, foreign orientation, organizational absorptive capacity)? Third, What are the marketing strategies of korean BGV and is it different from others? Under these problems, I test then (1) whether the BGV that a firm started its internationalization activity almost from inception, has more intangible resources(foreign experience of corporate members, foreign orientation, technological competences and absorptive capacity) than any other venture firms(Non_BGV) and (2) also whether the BGV's marketing strategies-differentiation, low price, market diversification and preemption strategy are different from Non_BGV. Above all, the main purpose of this research is that results achieved by BGV are indeed better than those obtained by Non_BGV firms with respect to firm's growth rate and efficiency. To do this research, I surveyed venture companies located in Seoul and Deajeon in Korea during November to December, 2005. I gather the data from 200 venture companies and then selected 84 samples, which have been founded during 1999${\sim}$2000. To compare BGV's characteristics with those of Non_BGV, I also had to classify BGV by export intensity over 50% among five or six aged venture firms. Many other researches tried to classify BGV and Non_BGV, but there were various criterion as many as researchers studied on this topic. Some of them use time gap, which is time difference of establishment and it's first internationalization experience and others use export intensity, ration of export sales amount divided by total sales amount. Although using a mixed criterion of prior research in my case, I do think this kinds of criterion is subjective and arbitrary rather than objective, so I do mention my research has some critical limitation in the classification of BGV and Non_BGV. The first purpose of research is the test of difference of performance between BGV and Non_BGV. As a result of t-test, the research show that there are statistically efficient difference not only in the growth rate (sales growth rate compared to competitors and 3 years averaged sales growth rate) but also in general market performance of BGV. But in case of profitability performance, the hypothesis that is BGV is more profit (return on investment(ROI) compared to competitors and 3 years averaged ROI) than Non-BGV was not supported. From these results, this paper concludes that BGV grows rapidly and gets a high market performance (in aspect of market share and customer loyalty) but there is no profitability difference between BGV and Non_BGV. The second result is that BGV have more absorptive capacity especially, knowledge competence, and entrepreneur's international experience than Non_BGV. And this paper also found BGV search for product differentiation, exemption strategy and market diversification strategy while Non_BGV search for low price strategy. These results have never been dealt with other existing studies. This research has some limitations. First limitation is concerned about the definition of BGV, as I mentioned above. Conceptually speaking, BGV is defined as company pursue internationalization from inception, but in empirical study, it's very difficult to classify between BGV and Non_BGV. I tried to classify on the basis of time difference and export intensity, this criterions are so subjective and arbitrary that the results are not robust if the criterion were changed. Second limitation is concerned about sample used in this research. I surveyed venture companies just located in Seoul and Daejeon and also use only 84 samples which more or less provoke sample bias problem and generalization of results. I think the more following studies that focus on ventures located in other region, the better to verify the results of this paper.

• Microbiology and Biotechnology Letters
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• v.39 no.4
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• pp.364-373
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• 2011

Human embryonic stem cells have been highlighted as a valuable cellular source in the regenerative medicine field, due to their pluripotency. However, there is the challenge of the establishment of specific functional cell type forms of undifferentiated human embryonic stem cells (hESC). To establish and purify functional cell types from hESCs, we differentiated undifferentiated hESCs into vascular lineage cells and sorted the specific cell population from the whole cell population, depending on their cell volume, and compared them with the non-sorted cell population. We observed that about 10% of the PECAM positive population existed in the VEGF induced differentiating human embryoid body (hEB), and differentiated hEBs were made into single cells for cell transplantation. After making single cells, we performed cell sorting using a fluorescence-activated cell sorter (FACs), according to their cell volume on the basis of FSC region gating, and compared their therapeutic capacity with the non-sorted cell population through cell transplantation into hindlimb ischemic disease model mice. 4 Weeks after cell transplantation, the recovery rate of blood perfusion reached 54% and 17% in the FSC regions of sorted cells- and non-sorted cells, respectively. This result suggests that derivation of a functional cell population from hESCs can be performed through cell sorting on the basis of cell volume after preliminary differentiation induction. This approach may then greatly contribute to overcoming the limitations of marker sorting.

• The Korean Journal of Pharmacology
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• v.26 no.2
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• pp.193-207
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• 1990

Transforming growth factor ${\beta}(TGF-{\beta})$ is a multifunctional polypeptide with diverse effects on the proliferation, differentiation and other functions in many cell types. $TGF-{\beta}$ is highly abundant in bone matrix and induces divergent responses in many aspects of bone cell metabolism . Several lines of investigation indicate that matrix-associated $TGF-{\beta}$ is the products of bone cells themselves. However, exact bone cell type reponsible for the production of $TGF-{\beta}$ is still in controversy, The present study was undertaken to determine the cellular origin of matrix-associated $TGF-{\beta}$ and to assess how different bone cells respond to $TGF-{\beta}$. As a prerequisite for this, 5 bone cell populations of distinct phenotype were isolated from fetal calvaria with sequential enzyme digestion protocol and biochemical characterization. Calvarial cell populations released in early stage showed fibroblastic features whereas populations relesed later was enriched with osteoblast-like cell as judged by their acid and alkaline phosphatase activities, cAMP responsiveness to parathyroid hormone, calcitonin and prostaglandin $E_2$ and collagen synthesis rate. By polyacylamide gel and immunoblot analysis of bone and calvarial cell extracts, presence of $TGF-{\beta}$ in bone tissues and production of $TGF-{\beta}$ by bone cells were confirmed again. Subsequent analysis of calvarial cell extracts prepared as individual population revealed that all calvarial cell populations synthesize $TGF-{\beta}$. Exogenously added $TGF-{\beta}$ induced biphasic response upon bone cell proliferation under serum-free condition. In osteoblastic cell populations, it was stimulatory whereas inhibitory in fibroblastic cell populations. In contrast, collagen and noncollagen protein synthesis of all calvarial cell populations were stimulated by $TGF-{\beta}$. Enhancement of protein synthesis was found to be more general rather than specific for collagen synthesis. In addition, effects of $TGF-{\beta}$ on protein synthesis were independent to its effects on cell proliferation. In summary, production of $TGF-{\beta}$ by bone cells and differential actions on various cell populations observed in this study suggest that $TGF-{\beta}$ may play an important role in the regulation of bone metabolism by modulating the specific cellular functions in autocrine and paracrine fashion.

• The Journal of Internal Korean Medicine
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• v.26 no.2
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• pp.440-452
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• 2005

Objective: In the winter of 2002, severe acute respiratory syndrome(SARS) began to spread throughout the world. More than 5,000 cases were reported in China, including over 1,700 cases in Hong Kong Special Administrative Region(Hong Kong SAR). The total number of cases reported from Canada and Singapore was more than 200. The total number of SARS cases world-wide reached 8,437 with incidences in 29 counties. Mortality from SARS is estimated at $10{\sim}12%$. When the SARS outbreak occurred in China, the State Administration of Traditional Chinese Medicine of China immediately initiated clinical research projects on the use of integrated herbal medicine and Western medicine for treating SARS. and, in Hong Kong SAR, research on the use of herbal medicine for the prevention and treatment of SARS. Reports were released during convalescence. The objective of this study is to overview twelve clinical SARS reports of WHO on the treatment of SARS with herbal medicine and evaluate the efficacy and safety of treatment of SARS with herbal medicine, and further to share experiences and knowledge of the treatment of SARS. Methods: Twelve clinical reports about SARS from the WHO were selected, overviewed and evaluated for efficacy and safety of treatments of SARS. Results and Conclusion: Twelve clinical reports about SARS showed that the integrated treatment may have advantages, and the advantages are reflected in the following findings: Firstly, herbal medicine is not targeted only at a specific etiology or a certain pathological link, but also at the pathological status of the patients at that particular time. Therefore, comprehensive readjustment was made through various angles, targets and channels to restore the balance of the body. Secondly, there are advantages in the differentiation of the disease and the treatment. Based on the various symptoms, herbal medicine enables the physician to adopt the most suitable principle, provide individual treatment, and to administer medicine in accordance with the actual process and nature of the illness. Thirdly, there are advantages in the results of the treatment; herbal medicine can relieve symptoms, promote absorption of lung inflammation, improve the degree of blood oxygen saturation, regulate immunological functions, reduce the required dosage of glucocorticoid and other Western medicines, and reduce case fatality rate, in addition to lowering the cost of treatment.