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Search Results: 1 - 10 of 26382 matches for " Hui-Jeong Gwon "
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Effect of Addition of Soybean Oil and Gamma-Ray Cross-linking on the Nanoporous HDPE Membrane
Jong-Seok Park,Jong-Bae Choi,Hui-Jeong Gwon,Youn-Mook Lim,Myung Seob Khil,Phil-Hyun Kang,Young-Chang Nho
Journal of Nanomaterials , 2012, DOI: 10.1155/2012/418021
Abstract: A nanoporous high-density polyethylene (HDPE) membrane was prepared by a wet process. Soybean oil and dibutyl phthalate (DBP) were premixed as codiluents, and gamma-rays were used for the cross-linking of HDPE. The pore volume of the nanoporous HDPE membranes with soybean oil was affected by the extracted amount of oil. The tensile strength of the membrane improved with an increasing absorbed dose up to 60 kGy, but decreased at 80 kGy due to severe degradation. The ionic conductivity of the nanoporous HDPE membrane did not really change with an increasing absorbed dose because the pores had already been formed before the gamma-ray radiation. Finally, the electrochemical stability of the HDPE membrane increased when the absorbed dose increased up to 60 kGy.
Characterization and Antimicrobial Property of Poly(Acrylic Acid) Nanogel Containing Silver Particle Prepared by Electron Beam
Jong-Bae Choi,Jong-Seok Park,Myung-Seob Khil,Hui-Jeong Gwon,Youn-Mook Lim,Sung-In Jeong,Young-Min Shin,Young-Chang Nho
International Journal of Molecular Sciences , 2013, DOI: 10.3390/ijms140611011
Abstract: In this study, we developed a one step process to synthesize nanogel containing silver nanoparticles involving electron beam irradiation. Water-soluble silver nitrate powder is dissolved in the distilled water and then poly(acrylic acid) (PAAc) and hexane are put into this silver nitrate solution. These samples are irradiated by an electron beam to make the PAAc nanogels containing silver nanoparticles (Ag/PAAc nanogels). The nanoparticles were characterized by scanning electron microscopy (SEM) and energy dispersive spectroscopy (EDS). In addition, the particle size and zeta-potential were confirmed by a particle size analyzer (PSA). The antibacterial properties of the nanogels were evaluated by paper diffusion test. The Ag/PAAc nanogels had an antibacterial effect against Escherichia coli and Staphylococcus aureus. The nanogels also demonstrated a good healing effect against diabetic ulcer. The size of the Ag/PAAc nanogels decreased with increasing irradiation doses, and the absolute value of the zeta potential increased with increasing irradiation doses. Also, the Ag/PAAc nanogels exhibited good antibacterial activity against both Gram-negative and Gram-positive bacteria. In in vivo wound healing, the Ag/PAAc nanogels have a good healing effect.
Retinoid production using metabolically engineered Escherichia coli with a two-phase culture system
Hui-Jeong Jang, Sang-Hwal Yoon, Hee-Kyung Ryu, Jung-Hun Kim, Chong-Long Wang, Jae-Yean Kim, Deok-Kun Oh, Seon-Won Kim
Microbial Cell Factories , 2011, DOI: 10.1186/1475-2859-10-59
Abstract: Among the BCM(D)O tested in E. coli, the synthetic retinoid synthesis protein (SR), based on bacteriorhodopsin-related protein-like homolog (Blh) of the uncultured marine bacteria 66A03, showed the highest β-carotene cleavage activity with no residual intracellular β-carotene. By introducing the exogenous MVA pathway, 8.7 mg/L of retinal was produced, which is 4-fold higher production than that of augmenting the MEP pathway (dxs overexpression). There was a large gap between retinal production and β-carotene consumption using the exogenous MVA pathway; therefore, the retinal derivatives were analyzed. The derivatives, except for retinoic acid, that formed were identified, and the levels of retinal, retinol, and retinyl acetate were measured. Amounts as high as 95 mg/L retinoids were obtained from engineered E. coli DH5α harboring the synthetic SR gene and the exogenous MVA pathway in addition to dxs overexpression, which were cultured at 29°C for 72 hours with 2YT medium containing 2.0% (w/v) glycerol as the main carbon source. However, a significant level of intracellular degradation of the retinoids was also observed in the culture. To prevent degradation of the intracellular retinoids through in situ extraction from the cells, a two-phase culture system with dodecane was used. The highest level of retinoid production (136 mg/L) was obtained after 72 hours with 5 mL of dodecane overlaid on a 5 mL culture.In this study, we successfully produced 136 mg/L retinoids, which were composed of 67 mg/L retinal, 54 mg/L retinol, and 15 mg/L retinyl acetate, using a two-phase culture system with dodecane, which produced 68-fold more retinoids than the initial level of production (2.2 mg/L). Our results demonstrate the potential use of E. coli as a promising microbial cell factory for retinoid production.Retinoids are a class of lipophilic isoprenoid molecules that are related chemically to vitamin A [1]. Retinoids are composed of a β-ionone ring and a polyunsaturated side ch
Protective Efficacy of a Human Endogenous Retrovirus Envelope-Coated, Nonreplicable, Baculovirus-Based Hemagglutin Vaccine against Pandemic Influenza H1N1 2009
Jae-Yoo Choi, Yong-Dae Gwon, Jeong-Ki Kim, Yeon-Dong Cho, Yoon-Ki Heo, Han-Sam Cho, Tae-Jin Choi, Ha-Ryoung Poo, Yu-Kyoung Oh, Young Bong Kim
PLOS ONE , 2013, DOI: 10.1371/journal.pone.0080762
Abstract: Despite the advantages of DNA vaccines, overcoming their lower efficacy relative to that of conventional vaccines remains a challenge. Here, we constructed a human endogenous retrovirus (HERV) envelope-coated, nonreplicable, baculovirus-based HA vaccine against swine influenza A/California/04/2009(H1N1) hemagglutin (HA) (AcHERV-sH1N1-HA) as an alternative to conventional vaccines and evaluated its efficacy in two strains of mice, BALB/c and C57BL/6. A commercially available, killed virus vaccine was used as a positive control. Mice were intramuscularly administered AcHERV-sH1N1-HA or the commercial vaccine and subsequently given two booster injections. Compared with the commercial vaccine, AcHERV-sH1N1-HA induced significantly higher levels of cellular immune responses in both BALB/c and C57BL/6 mice. Unlike cellular immune responses, humoral immune responses depended on the strain of mice. Following immunization with AcHERV-sH1N1-HA, C57BL/6 mice showed HA-specific IgG titers 10- to 100-fold lower than those of BALB/c mice. In line with the different levels of humoral immune responses, the survival of immunized mice after intranasal challenge with sH1N1 virus (A/California/04/2009) depended on the strain. After challenge with 10-times the median lethal dose (MLD50) of sH1N1 virus, 100% of BALB/c mice immunized with the commercial vaccine or AcHERV-sH1N1-HA survived. In contrast, C57BL/6 mice immunized with AcHERV-sH1N1-HA or the commercial vaccine showed 60% and 70% survival respectively, after challenge with sH1N1 virus. In all mice, virus titers and results of histological analyses of lung tissues were consistent with the survival data. Our results indicate the importance of humoral immune response as a major defense system against influenza viral infection. Moreover, the complete survival of BALB/c mice immunized with AcHERV-sH1N1-HA after challenge with sH1N1 virus suggests the potential of baculoviral vector-based vaccines to achieve an efficacy comparable to that of killed virus vaccines.
Evaluation of Network Stack Optimization Techniques for Wireless Sensor Networks  [PDF]
Jaein JEONG
Int'l J. of Communications, Network and System Sciences (IJCNS) , 2009, DOI: 10.4236/ijcns.2009.28083
Abstract: We present a network stack implementation for a wireless sensor platform based on a byte-level radio. The network stack provides error-correction code, multi-channel capability and reliable communication for a high packet reception rate as well as a basic packet-level communication interface. In outdoor tests, the packet reception rate is close to 100% within 800 ft and is reasonably good up to 1100 ft. This is made possible by using error correction code and a reliable transport layer. Our implementation also allows us to choose a fre-quency among multiple channels. By using multiple frequencies as well as a reliable transport layer, we can achieve a high packet reception rate by paying additional retransmission time when collisions increase with additional sensor nodes.
Characterization of Multicultural Values: Affective Impact of Writing Extensive Journals in a University-Level Course  [PDF]
Taekhil Jeong
Creative Education (CE) , 2013, DOI: 10.4236/ce.2013.47A2022
Abstract:

The highest educational objective of affective domain is characterization, which refers to the level of character development where individuals’ behaviors and values remain consistent. Because the educational objectives of affect are categorically different from cognitive educational objectives, an alternative pedagogical conceptualization that integrates teaching, learning, and evaluating aspects of character development is essential in multicultural education. The current action research presents: 1) a rubric of multicultural education journal writing that evaluates the quality of students’ journals; 2) coherent journal topics and accessible resources for journal entries; and 3) exemplary student journals that sufficiently meet the criteria of rubric, topic, and resource requirements. The presented rubric, topics, resources, and actual student journal examples may serve as a model that both multicultural education teachers and students alike can utilize in their teaching and learning practices.

A Study on the Impact of South Korea’s Official Developmental Assistance Policy toward Vietnam  [PDF]
Seungho Jeong
Modern Economy (ME) , 2018, DOI: 10.4236/me.2018.98091
Abstract: The purpose of this research paper is to study and analyze the Official Development Assistance (ODA) policy of South Korea toward Vietnam. The research methodology used was qualitative and relied on processed information from secondary sources. It is noted that South Korea has been a major foreign aid partner of Vietnam since it became a donor member of the Development Assistance Committee (DAC). Currently, South Korea preferentially gives Vietnam the largest share of its donor funds in the form of concessional loans and grants. Also found in this investigation is that the main determinant of this sizable ODA is in the form of commercial opportunities available in the recipient country and the rich diplomatic relations shared by the two countries. South Korea has realized commercial benefits such as an expanded market for exports, employment opportunities for its citizens, and foreign direct investment (FDI) chances in Vietnam as a result of this ODA volume. On the other hand, Vietnam has used money received to immensely transform its economy. In conclusion, the ODA policy of South Korea toward Vietnam has been found to be largely beneficial for both countries.
Multimodal sparse representation learning and applications
Miriam Cha,Youngjune Gwon,H. T. Kung
Computer Science , 2015,
Abstract: Unsupervised methods have proven effective for discriminative tasks in a single-modality scenario. In this paper, we present a multimodal framework for learning sparse representations that can capture semantic correlation between modalities. The framework can model relationships at a higher level by forcing the shared sparse representation. In particular, we propose the use of joint dictionary learning technique for sparse coding and formulate the joint representation for concision, cross-modal representations (in case of a missing modality), and union of the cross-modal representations. Given the accelerated growth of multimodal data posted on the Web such as YouTube, Wikipedia, and Twitter, learning good multimodal features is becoming increasingly important. We show that the shared representations enabled by our framework substantially improve the classification performance under both unimodal and multimodal settings. We further show how deep architectures built on the proposed framework are effective for the case of highly nonlinear correlations between modalities. The effectiveness of our approach is demonstrated experimentally in image denoising, multimedia event detection and retrieval on the TRECVID dataset (audio-video), category classification on the Wikipedia dataset (image-text), and sentiment classification on PhotoTweet (image-text).
Proteome analysis of developing mice diastema region
Young-Mi Chae1, Young-Joo Jin1, Hyeng-Soo Kim2, Gi-Jeong Gwon1, Wern-Joo Sohn1,2, Sung-Hyun Kim3, Myoung-Ok Kim4, Sanggyu Lee2, Jo-Young Suh5 & Jae-Young Kim1*
BMB Reports , 2012,
Abstract: Different from humans, who have a continuous dentition ofteeth, mice have only three molars and one incisor separatedby a toothless region called the diastema in the hemimandibular arch. Although tooth buds form in the embryonicdiastema, they regress and do not develop into teeth. In thisstudy, we evaluated the proteins that modulate the diastemaformation through comparative analysis with molar-formingtissue by liquid chromatography-tandem mass spectroscopy(LC-MS/MS) proteome analysis. From the comparative andsemi-quantitative proteome analysis, we identified 147 up- and173 down-regulated proteins in the diastema compared to themolar forming proteins. Based on this proteome analysis, weselected and evaluated two candidate proteins, EMERIN andRAB7A, as diastema tissue specific markers. This studyprovides the first list of proteins that were detected in themouse embryonic diastema region, which will be useful tounderstand the mechanisms of tooth development.
Overexpression of Snail is associated with lymph node metastasis and poor prognosis in patients with gastric cancer
Shin Na Ri,Jeong Eun Hui,Choi Chang In,Moon Hyun Jung
BMC Cancer , 2012, DOI: 10.1186/1471-2407-12-521
Abstract: Background Epithelial–mesenchymal transition (EMT) plays a significant role in tumor progression and invasion. Snail is a known regulator of EMT in various malignant tumors. This study investigated the role of Snail in gastric cancer. Methods We examined the effects of silenced or overexpressed Snail using lenti-viral constructs in gastric cancer cells. Immunohistochemical analysis of tissue microarrays from 314 patients with gastric adenocarcinoma (GC) was used to determine Snail’s clinicopathological and prognostic significance. Differential gene expression in 45 GC specimens with Snail overexpression was investigated using cDNA microarray analysis. Results Silencing of Snail by shRNA decreased invasion and migration in GC cell lines. Conversely, Snail overexpression increased invasion and migration of gastric cancer cells, in line with increased VEGF and MMP11. Snail overexpression (≥75% positive nuclear staining) was also significantly associated with tumor progression (P < 0.001), lymph node metastases (P = 0.002), lymphovascular invasion (P = 0.002), and perineural invasion (P = 0.002) in the 314 GC patients, and with shorter survival (P = 0.023). cDNA microarray analysis revealed 213 differentially expressed genes in GC tissues with Snail overexpression, including genes related to metastasis and invasion. Conclusion Snail significantly affects invasiveness/migratory ability of GCs, and may also be used as a predictive biomarker for prognosis or aggressiveness of GCs.
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