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Search Results: 1 - 10 of 44677 matches for " Jin-Kyu Song "
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Effective punching shear and moment capacity of flat plate-column connection with shear reinforcements for lateral loading
Jin-Kyu Song,Jubum Kim,Ho-Bum Song,Jeong-Won Song
International Journal of Concrete Structures and Materials , 2012, DOI: 10.1007/s40069-012-0002-3
Abstract: In this study, three isolated interior flat slab-column connections that include three types of shear reinforcement details; stirrup, shear stud and shear band were tested under reversed cyclic lateral loading to observe the capacity of slab-column connections. These reinforced joints are 2/3 scale miniatures designed to have identical punching capacities. These experiments showed that the flexural failure mode appears in most specimens while the maximum unbalanced moment and energy absorbing capacity increases effectively, with the exception of an unreinforced standard specimen. Finally, the results of the experiments, as wel l as those of experiments previously carried out by researchers, are applied to the eccentricity shear stress model presented in ACI 318-08. The failure mode is therefore defined in this study by considering the upper limits for punching shear and unbalanced momen t. In addition, an intensity factor is proposed for effective widths of slabs that carry an unbalanced moment delivered by bending.
MIMO Technologies in 3GPP LTE and LTE-Advanced
Lee Juho,Han Jin-Kyu,Zhang Jianzhong(Charlie)
EURASIP Journal on Wireless Communications and Networking , 2009,
Abstract: 3rd Generation Partnership Project (3GPP) has recently completed the specification of the Long Term Evolution (LTE) standard. Majority of the world's operators and vendors are already committed to LTE deployments and developments, making LTE the market leader in the upcoming evolution to 4G wireless communication systems. Multiple input multiple output (MIMO) technologies introduced in LTE such as spatial multiplexing, transmit diversity, and beamforming are key components for providing higher peak rate at a better system efficiency, which are essential for supporting future broadband data service over wireless links. Further extension of LTE MIMO technologies is being studied under the 3GPP study item "LTE-Advanced" to meet the requirement of IMT-Advanced set by International Telecommunication Union Radiocommunication Sector (ITU-R). In this paper, we introduce various MIMO technologies employed in LTE and provide a brief overview on the MIMO technologies currently discussed in the LTE-Advanced forum.
MIMO Technologies in 3GPP LTE and LTE-Advanced
Juho Lee,Jin-Kyu Han,Jianzhong (Charlie) Zhang
EURASIP Journal on Wireless Communications and Networking , 2009, DOI: 10.1155/2009/302092
Abstract: 3rd Generation Partnership Project (3GPP) has recently completed the specification of the Long Term Evolution (LTE) standard. Majority of the world's operators and vendors are already committed to LTE deployments and developments, making LTE the market leader in the upcoming evolution to 4G wireless communication systems. Multiple input multiple output (MIMO) technologies introduced in LTE such as spatial multiplexing, transmit diversity, and beamforming are key components for providing higher peak rate at a better system efficiency, which are essential for supporting future broadband data service over wireless links. Further extension of LTE MIMO technologies is being studied under the 3GPP study item “LTE-Advanced” to meet the requirement of IMT-Advanced set by International Telecommunication Union Radiocommunication Sector (ITU-R). In this paper, we introduce various MIMO technologies employed in LTE and provide a brief overview on the MIMO technologies currently discussed in the LTE-Advanced forum.
Quantitative Analysis and Efficient Surface Modification of Silica Nanoparticles
Hak-Sung Jung,Doo-Sik Moon,Jin-Kyu Lee
Journal of Nanomaterials , 2012, DOI: 10.1155/2012/593471
Abstract: Aminofunctional trialkoxysilanes such as aminopropyltrimethoxysilane (APTMS) and (3-trimethoxysilylpropyl)diethylenetriamine (DETAS) were employed as a surface modification molecule for generating monolayer modification on the surface of silica (SiO2) nanoparticles. We were able to quantitatively analyze the number of amine functional groups on the modified SiO2 nanoparticles by acid-base back titration method and determine the effective number of amine functional groups for the successive chemical reaction by absorption measurements after treating with fluorescent rhodamine B isothiocyanate (RITC) molecules. The numbers of amine sites measured by back titration were 2.7 and 7.7 ea/nm2 for SiO2-APTMS and SiO2-DETAS, respectively, while the numbers of effective amine sites measured by absorption calibration were about one fifth of the total amine sites, namely, 0.44 and 1.3 ea/nm2 for SiO2-APTMS(RITC) and SiO2-DETAS(RITC), respectively. Furthermore, it was confirmed that the reactivity of amino groups on the surface-modified silica nanoparticles could be maintained in ethanol for more than 1.5 months without showing any significant differences in the reactivity.
Buddleja officinalis Maximowicz Extract Inhibits Lipid Accumulation on Adipocyte Differentiation in 3T3-L1 Cells and High-Fat Mice
Changhyun Roh,Min-Kyoung Park,Hee-June Shin,Uhee Jung,Jin-Kyu Kim
Molecules , 2012, DOI: 10.3390/molecules17078687
Abstract: Obesity is a global health problem. It is also known to be a risk factor for the development of metabolic disorders, type 2 diabetes, systemic hypertension, cardiovascular disease, dyslipidemia, and atherosclerosis. In this study, we elucidated that Buddleja officinalis Maximowicz extract significantly inhibited lipid accumulation during 3T3-L1 adipocyte differentiation. Furthermore, Buddleja officinalis Maximowicz extract reduced the body weight gain induced through feeding a high-fat diet to C57BL/6 mice. The treatment of Buddleja officinalis Maximowicz extract significantly reduced the adipose tissue weight to 2.7/100 g of body weight in high-fat mice. When their adipose tissue morphology was investigated for histochemical staining, the distribution of cell size in the high-fat diet groups was hypertrophied compared with those from Buddleja officinalis Maximowicz extract-treated mice. In addition, in Buddleja officinalis Maximowicz extract-treated mice, a significant reduction of serum triglyceride and T-cholesterol was observed at to 21% and 17%, respectively. The discovery of bioactive compounds from diet or dietary supplementation is one of possible ways to control obesity and to prevent or reduce the risks of various obesity-related diseases. These results support that Buddleja officinalis Maximowicz extract is expected to create the therapeutic interest with respect to the treatment of obesity.
Lasing in localized modes of a slow light photonic crystal waveguide
Jin-Kyu Yang,Heeso Noh,Michael J. Rooks,Glenn S. Solomon,Frank Vollmer,Hui Cao
Physics , 2011, DOI: 10.1063/1.3600344
Abstract: We demonstrate lasing in GaAs photonic crystal waveguides with InAs quantum dots as gain medium. Structural disorder is present due to fabrication imperfection and causes multiple scat- tering of light and localization of light. Lasing modes with varying spatial extend are observed at random locations along the guide. Lasing frequencies are determined by the local structure and occur within a narrow frequency band which coincides with the slow light regime of the waveguide mode. The three-dimensional numerical simulation reveals that the main loss channel for lasing modes located away from the waveguide end is out-of-plane scattering by structural disorder.
Ultraviolet and visible range plasmonics of a topological insulator
Jun-Yu Ou,Jin-Kyu So,Giorgio Adamo,Azat Sulaev,Lan Wang,Nikolay I. Zheludev
Physics , 2014, DOI: 10.1038/ncomms6139
Abstract: The development of metamaterials, data processing circuits and sensors for the visible and UV parts of the spectrum is hampered by the lack of low-loss media supporting plasmonic excitations and drives the intense search for plasmonic materials beyond noble metals. By studying plasmonic nanostructures fabricated on the surface of topological insulator $\mbox{Bi}_{1.5}\mbox{Sb}_{0.5}\mbox{Te}_{1.8}\mbox{Se}_{1.2}$ we found that it is orders of magnitude better plasmonic material than gold and silver in the blue-UV range. Metamaterial fabricated from $\mbox{Bi}_{1.5}\mbox{Sb}_{0.5}\mbox{Te}_{1.8}\mbox{Se}_{1.2}$ show plasmonic resonances from 350 nm to 550 nm while surface gratings exhibit cathodoluminescent peaks from 230 nm to 1050 nm. The negative permittivity underpinning plasmonic response is attributed to the combination of bulk interband transitions and surface contribution of the topologically protected states. The importance of our result is in the identification of new mechanisms of negative permittivity in semiconductors where visible-range plasmonics can be directly integrated with electronics.
Epigenetic Changes of Lentiviral Transgenes in Porcine Stem Cells Derived from Embryonic Origin
Kwang-Hwan Choi, Jin-Kyu Park, Hye-Sun Kim, Kyung-Jun Uh, Dong-Chan Son, Chang-Kyu Lee
PLOS ONE , 2013, DOI: 10.1371/journal.pone.0072184
Abstract: Because of the physiological and immunological similarities that exist between pigs and humans, porcine pluripotent cell lines have been identified as important candidates for preliminary studies on human disease as well as a source for generating transgenic animals. Therefore, the establishment and characterization of porcine embryonic stem cells (pESCs), along with the generation of stable transgenic cell lines, is essential. In this study, we attempted to efficiently introduce transgenes into Epiblast stem cell (EpiSC)-like pESCs. Consequently, a pluripotent cell line could be derived from a porcine-hatched blastocyst. Enhanced green fluorescent protein (EGFP) was successfully introduced into the cells via lentiviral vectors under various multiplicities of infection, with pluripotency and differentiation potential unaffected after transfection. However, EGFP expression gradually declined during extended culture. This silencing effect was recovered by in vitro differentiation and treatment with 5-azadeoxycytidine. This phenomenon was related to DNA methylation as determined by bisulfite sequencing. In conclusion, we were able to successfully derive EpiSC-like pESCs and introduce transgenes into these cells using lentiviral vectors. This cell line could potentially be used as a donor cell source for transgenic pigs and may be a useful tool for studies involving EpiSC-like pESCs as well as aid in the understanding of the epigenetic regulation of transgenes.
Crystal structure of hyperthermophilic esterase EstE1 and the relationship between its dimerization and thermostability properties
Jung-Sue Byun, Jin-Kyu Rhee, Nam Kim, JeongHyeok Yoon, Dong-Uk Kim, Eunhee Koh, Jong-Won Oh, Hyun-Soo Cho
BMC Structural Biology , 2007, DOI: 10.1186/1472-6807-7-47
Abstract: Here we report for the first time the 2.1-? resolution crystal structure of EstE1. The three-dimensional structure of EstE1 exhibits a classic α/β hydrolase fold with a central parallel-stranded beta sheet surrounded by alpha helices on both sides. The residues Ser154, Asp251, and His281 form the catalytic triad motif commonly found in other α/β hydrolases. EstE1 exists as a dimer that is formed by hydrophobic interactions and salt bridges. Circular dichroism spectroscopy and heat inactivation kinetic analysis of EstE1 mutants, which were generated by structure-based site-directed mutagenesis of amino acid residues participating in EstE1 dimerization, revealed that hydrophobic interactions through Val274 and Phe276 on the β8 strand of each monomer play a major role in the dimerization of EstE1. In contrast, the intermolecular salt bridges contribute less significantly to the dimerization and thermostability of EstE1.Our results suggest that intermolecular hydrophobic interactions are essential for the hyperthermostability of EstE1. The molecular mechanism that allows EstE1 to endure high temperature will provide guideline for rational design of a thermostable esterase/lipase using the lipolytic enzymes showing structural similarity to EstE1.Lipolytic enzymes, including esterases or carboxylesterases (EC 3.1.1.1) and lipases (EC 3.1.1.3), catalyze the stereospecific hydrolysis, transesterification, and conversion of a variety of amines and primary and secondary alcohols [1-3]. Esterases and carboxylesterases hydrolyze partly-soluble fatty acid esters with acyl chain lengths of less than 10 carbon atoms [4], whereas lipases act on water-insoluble long-chain triglycerides. Many lipases and esterases have been isolated from a variety of microorganisms, animals, plants, and metagenomes [4,5].Thermostable esterases/lipases originate from thermophiles. Their extraordinary thermodynamic stability allows these enzymes to function in organic solvents, and at elevated temperat
Meibomian Epithelioma of the Lower Eyelid in a Thoroughbred Horse
Seong-Kyoon Choi1§, Jin-Kyu Park1§, Won Bae Jeon, Kyung-Hyun Lee2 and Gil-Jae Cho*
Pakistan Veterinary Journal , 2013,
Abstract: A 9-year old, castrated male, thoroughbred horse presented for a left lower eyelid mass with ocular signs of mucopurulent discharge, conjunctival hyperemia and ocular discomfort. On physical examination, there was no other abnormality. Surgically, the mass arising from the inner surface of left lower eyelid was excised and examined histopathologically. Microscopically, the eyelid mass exhibited neoplastic basaloid cells forming irregular cell masses of variable size separated by thin fibrous tissues. The basaloid cells showed mildly pleomorphic and undifferentiated appearances with prominent oval nuclei and scant cytoplasm. Poorly differentiated meibocytes were observed occasionally in the periphery regions of the cell masses suggesting the mass of lower eyelid originated from meibomian glands. Based on histopathological observation, the present case was diagnosed as an equine meibomian epithelioma in the lower eyelid. To the author’s knowledge, the present case is the first report of equine meibomian epithelioma in veterinary literatures.
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