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Search Results: 1 - 10 of 21090 matches for " Bong-Kyu Kim "
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Development of a three-dimensional nonlinear viscoelastic constitutive model of solid propellant
Jung, Gyoo-Dong;Youn, Sung-Kie;Kim, Bong-Kyu;
Journal of the Brazilian Society of Mechanical Sciences , 2000, DOI: 10.1590/S0100-73862000000300007
Abstract: a three dimensional nonlinear viscoelastic constitutive model for the solid propellant is developed. in their earlier work, the authors have developed an isotropic constitutive model and verified it for one dimensional case. in the present work, the validity of the model is extended to three-dimensional cases. large deformation, dewetting and cyclic loading effects are treated as the main sources of nonlinear behavior of the solid propellant. viscoelastic dewetting criteria is used and the softening of the solid propellant due to dewetting is treated by the modulus decrease. the nonlinearities during cyclic loading are accounted for by the functions of the octahedral shear strain measure. the constitutive equation is implemented into a finite element code for the analysis of propellant grains. a commercial finite element package ?abaqus? is used for the analysis and the model is introduced into the code through a user subroutine. the model is evaluated with different loading conditions and the predicted values are in good agreement with the measured ones. the resulting model applied to analyze a solid propellant grain for the thermal cycling load.
Development of a three-dimensional nonlinear viscoelastic constitutive model of solid propellant
Jung Gyoo-Dong,Youn Sung-Kie,Kim Bong-Kyu
Journal of the Brazilian Society of Mechanical Sciences , 2000,
Abstract: A three dimensional nonlinear viscoelastic constitutive model for the solid propellant is developed. In their earlier work, the authors have developed an isotropic constitutive model and verified it for one dimensional case. In the present work, the validity of the model is extended to three-dimensional cases. Large deformation, dewetting and cyclic loading effects are treated as the main sources of nonlinear behavior of the solid propellant. Viscoelastic dewetting criteria is used and the softening of the solid propellant due to dewetting is treated by the modulus decrease. The nonlinearities during cyclic loading are accounted for by the functions of the octahedral shear strain measure. The constitutive equation is implemented into a finite element code for the analysis of propellant grains. A commercial finite element package ?ABAQUS? is used for the analysis and the model is introduced into the code through a user subroutine. The model is evaluated with different loading conditions and the predicted values are in good agreement with the measured ones. The resulting model applied to analyze a solid propellant grain for the thermal cycling load.
Gene expression profile of the skin in the 'hairpoor' (HrHp) mice by microarray analysis
Bong-Kyu Kim, In-Cheol Baek, Hwa-Young Lee, Jeong-Ki Kim, Hae-Hiang Song, Sungjoo K Yoon
BMC Genomics , 2010, DOI: 10.1186/1471-2164-11-640
Abstract: From 45,282 mouse probes, differential expressions in 43 (>2-fold), 306 (>1.5-fold), and 1861 genes (>1.2-fold) in skin from HrHp/HrHp mice were discovered and compared with skin from wild-type mice. Among the 1861 genes with a > 1.2-fold increase in expression, further analysis showed that the expression of eight genes known to have a close relationship with hair follicle development, ascertained by conducting real-time PCR on skin RNA produced during hair follicle morphogenesis (P0-P14), indicated that four genes, Wif1, Casp14, Krt71, and Sfrp1, showed a consistent expression pattern with respect to HR overexpression in vivo.Wif1 and Casp14 were found to be upregulated, whereas Krt71 and Sfrp1 were downregulated in cells overexpressing HR in transient transfection experiments on keratinocytes, suggesting that HR may transcriptionally regulate these genes. Further studies are required to understand the mechanism of this regulation by the HR cofactor.With a complex and dynamic structure, hair is generated by hair-producing follicles and has a patterned cycle of growth and remodeling, which consists of growth (anagen), regression (catagen), and rest (telogen) stages. There are many genes involved in mature hair follicle (HF) regulation [1].One of these genes, hairless (Hr), is expressed in skin, specifically in the suprabasal cell layer of the interfollicular epidermis and in the lower portion of the HF epithelium; its expression is dependent on the hair cycle. Hr encodes a 130 kDa protein (HR), which contains a zinc finger domain and is localized in the nucleus [2], and acts as a transcriptional corepressor that regulates transcription through directly binding to the thyroid hormone receptor [3,4], vitamin D receptor [5], and retinoic acid-like orphan receptor α [6].Various Hr mutant mice have been studied to understand the function of HR, and most Hr mutant mice are created by causing the loss of HR function in their cells, giving them a typical phenotype with a re
A Review of the Genus Grapholita (Lepidoptera, Tortricidae) in North Korea
Bong-Kyu Byun,Bong-Woo Lee,Kwan-Ho Bae,Kyung-Jae Lee
Animal Systematics, Evolution and Diversity , 2012, DOI: http://dx.doi.org/10.5635/ased.2012.28.4.291
Abstract: In North Korea, the first report of the family Tortricidae, comprising 34 species, was made in 1969. It includes three species of the genus Grapholita (G. inopinata, G. molesta, and G. turionana). Among them, G. turionana is now placed under the genus Blastesthia. In the present study, a total of four species of the genus Grapholita are recognized from North Korea, based on material deposited in the Hungarian Natural History Museum, Hungary. Of them, Grapholita molesta (Busck), is reported for the first time from North Korea. In the present study, G. inopinata was not found. All the known species are enumerated with illustrations of adults and genitalia. Also a key for the genus is given.
Using Process Indicators to Facilitate Data-Driven Decision Making in the Era of Accountability  [PDF]
Kyu Tae Kim
Creative Education (CE) , 2012, DOI: 10.4236/ce.2012.36102
Abstract: This paper explores which accountability indicators are likely to reveal the distinct contexts and qualitative characteristics of school that stimulate and improve authentic pedagogy and accountability. In the era of accountability, data-driven decision making is a new research area for authentic pedagogy through monitoring student progress and improving school accountability. It is based on input-and-result oriented indicators such as school demographics, facilities, budget, standardized test scores, dropout rates. But the indicators are unlikely to capture a dynamically interactive qualitative characteristics of school organizations featuring a loosely-coupled system and difficult to be measured or assessed. Thus, process indicators need to be complementary to input-and-outcome data for a valid and graphic description, monitoring and explanation of ‘why’ and ‘how’ the school outcomes occur. The author concluded that the data-driven decision making (DDDM) based on process indicators strengthens reflective professionalism and provides for the educational welfare for the poor and left-behind students.
Bambusae caulis in Liquamen Suppresses the Expression of Thymus and Activation-Regulated Chemokine and Macrophage-Derived Chemokine in Human Keratinocytes due to Antioxidant Effect
Xu-Feng Qi,Dong-Heui Kim,Yang-Suk Yoon,Soon-Bong Song,Yung-Chien Teng,Dong-Qing Cai,Kyu-Jae Lee
Evidence-Based Complementary and Alternative Medicine , 2012, DOI: 10.1155/2012/617494
Abstract: Bambusae caulis in Liquamen (BCL), traditional herbal medicine used in East Asia, is known to have antioxidative and immune-regulating properties. We hypothesized that the potential antioxidant effects of BCL might suppress the production of thymus and activation-regulated chemokine (TARC) and macrophage-derived chemokine (MDC) in human keratinocytes (HaCaT cell). The immune-regulating effect of BCL was demonstrated by antioxidant capacity using DPPH analysis and DCFH-DA analysis. We found that BCL had strong ROS scavenge effect in HaCaT cell. BCL also showed suppression of IFN-γ-induced expression of TARC and MDC, activation of NF-κB, and, moreover, significant block of IFN-γ-induced degradation and phosphorylation of IκB. However, it had no effects on phosphorylation of p38 MAPK. Collectively, these results suggest that BCL may have a therapeutic potential on skin disease such as atopic dermatitis by inhibiting Th2 chemokines which is due, at least in part, to its antioxidant capacities.
Functional characterization of the ER stress induced X-box-binding protein-1 (Xbp-1) in the porcine system
Jin-Yu Zhang, Kyu-Sun Lee, Ji-Su Kim, Bong-Seok Song, Dong-Il Jin, Deog-Bon Koo, Kweon Yu
BMC Molecular Biology , 2011, DOI: 10.1186/1471-2199-12-25
Abstract: We found that the pXbp1 mRNA was the subject of the IRE1α-mediated unconventional splicing by ER stress. Knock-down of pXbp1 enhanced ER stress-mediated cell death in PEF cells. In adult organs, pXbp1 mRNA and protein were expressed and the spliced forms were detected.It was first found that the UPR mechanisms and the function of pXbp1 in the porcine system. These results indicate that pXbp1 plays an important role during the ER stress response like other animal systems and open a new opportunity for examining the UPR pathway in the porcine model system.Endoplasmic reticulum (ER) is an essential cellular compartment for protein synthesis and maturation [1]. The perturbation of ER functions such as disruption of Ca++ homeostasis, inhibition of protein glycosylation or disulfide bond formation, hypoxia, and bacteria infections results in the accumulation of unfolded or mis-folded proteins in ER lumen. To reduce the excessive mis-folded protein loading, cells trigger unfolded protein response (UPR) including the transient attenuation of protein translation, the degradation of mis-folded proteins, and the induction of molecular chaperones and protein folding enzymes [1]. In severe ER stress, UPR results in cell death through the activation of apoptotic pathways [2].Three distinct UPR signaling pathways exist in mammalian cells that include ER transmembrane inositol-requiring enzyme 1 (IRE1), PKR-like ER kinase (PERK), and activating transcription factor 6 (ATF6) pwthways [3]. The evolutionary conserved IRE1 in the UPR pathway plays as a Ser/Thr protein kinase and endoribonuclease [4,5]. Upon the activation of IRE1α by ER stress, the endonuclease domain of IRE1 splices the XBP1 mRNA and removes 26 base pairs from the full-length XBP1 mRNA by the unconventional splicing. This event results in the conversion of the premature unspliced XBP1 protein (XBP1u, 267 amino acids) to the spliced XBP1 protein (XBP1s, 371 amino acids) by the frame shift. XBP1s induces a subset of UPR
GPS Receiver with Enhanced User Positioning Time
Seung-Hyun Yoon,Ji-Woon Jung,Su-Bong Kim,Hyun-Chang Shin,Jae-Hyang Lee,Kyu-Yun Lee,Hyo-Sun Shim
Computer Science , 2015,
Abstract: This paper introduces a Global Positioning System (GPS) Receiver that locates user's position instantly. Recently, many mobile devices require location information to add user position into their contents, and some applications require quick positioning when the device is initially switched on. In order to reduce the time to fix user's position, we propose the Instant-On GPS receiver system which is implemented on an ARM based FPGA board, and operates under a very low power mode. We've developed a repeated sleep mode by periods to control the GPS receiver's main power in order to achieve reduced power consumption. By using a high resolution Real Time Clock (RTC), we can estimate frame sync timing without receiving the current frame sync preamble data from a satellite when GPS turns back on. However, the navigation solution needs to be calculated once in advance. The performance results of the proposed GPS receiver in both real world and simulation environment are presented.
Genetic Differentiation among Populations and Color Variants of Sea Cucumbers (Stichopus Japonicus) from Korea and China
Jung-Ha Kang, Yi-Kyong Kim, Mi-Jung Kim, Jung-Yeon Park, Chul-Min An, Bong-Seok Kim, Je-Cheon Jun, Sang-Kyu Kim
International Journal of Biological Sciences , 2011,
Abstract: The Far Eastern sea cucumber, Stichopus japonicus, is a favored food in Eastern Asia, including Korea, Japan, and China. Aquaculture production of this species has increased because of recent declines in natural stocks and government-operated stock release programs are ongoing. Therefore, the analyses of genetic structure in wild and hatchery populations are necessary to maintain the genetic diversity of this valuable marine resource. In addition, given that sea cucumber color affects market price, with the rare, possibly reproductively isolated, red type being the most valuable, an understanding of the genetic structure and diversity in color variation of green and red types is necessary. We analyzed the genetic structure of wild and hatchery-produced green type S. japonicus from Korea and China, and wild red type from Korea using 9 microsatellite makers. The number of alleles per locus ranged from 11 to 29 across all populations. The mean allele numbers of the green types from Korea (10.6) and China (10.1) were similar, but differed slightly from that of the red type (9.1). Pairwise multilocus FST and genetic distance estimations showed no significant differences between the green types from Korea and China, whereas the differences between the green and red types were significant. This was clearly illustrated by a UPGMA dendrogram, in which the two close subclusters of green types were completely separated from the red type. In addition, the allele frequencies of the green and red types were significantly different. Assignment tests correctly assigned 100% (quality index 99.97%) of individuals to their original color types and demonstrated the feasibility of microsatellite analysis for discrimination between color types.
Diagnostic Application of Targeted Resequencing for Familial Nonsyndromic Hearing Loss
Byung Yoon Choi, Gibeom Park, Jungsoo Gim, Ah Reum Kim, Bong-Jik Kim, Hyo-Sang Kim, Joo Hyun Park, Taesung Park, Seung-Ha Oh, Kyu-Hee Han, Woong-Yang Park
PLOS ONE , 2013, DOI: 10.1371/journal.pone.0068692
Abstract: Identification of causative genes for hereditary nonsyndromic hearing loss (NSHL) is important to decide treatment modalities and to counsel the patients. Due to the genetic heterogeneity in sensorineural genetic disorders, the high-throughput method can be adapted for the efficient diagnosis. To this end, we designed a new diagnostic pipeline to screen all the reported candidate genes for NSHL. For validation of the diagnostic pipeline, we focused upon familial NSHL cases that are most likely to be genetic, rather than to be infectious or environmental. Among the 32 familial NSHL cases, we were able to make a molecular genetic diagnosis from 12 probands (37.5%) in the first stage by their clinical features, characteristic inheritance pattern and further candidate gene sequencing of GJB2, SLC26A4, POU3F4 or mitochondrial DNA. Next we applied targeted resequencing on 80 NSHL genes in the remaining 20 probands. Each proband carried 4.8 variants that were not synonymous and had the occurring frequency of less than three among the 20 probands. These variants were then filtered out with the inheritance pattern of the family, allele frequency in normal hearing 80 control subjects, clinical features. Finally NSHL-causing candidate mutations were identified in 13(65%) of the 20 probands of multiplex families, bringing the total solve rate (or detection rate) in our familial cases to be 78.1% (25/32) Damaging mutations discovered by the targeted resequencing were distributed in nine genes such as WFS1, COCH, EYA4, MYO6, GJB3, COL11A2, OTOF, STRC and MYO3A, most of which were private. Despite the advent of whole genome and whole exome sequencing, we propose targeted resequencing and filtering strategy as a screening and diagnostic tool at least for familial NSHL to find mutations based upon its efficacy and cost-effectiveness.
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