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Search Results: 1 - 10 of 3140 matches for " Deug-Nam Kwon "
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Alpha 1,3-Galactosyltransferase Deficiency in Pigs Increases Sialyltransferase Activities That Potentially Raise Non-Gal Xenoantigenicity
Jong-Yi Park,Mi-Ryung Park,Deug-Nam Kwon,Min-Hui Kang,Mihye Oh,Jae-Woong Han,Ssang-Goo Cho,Chankyu Park,Dong-Ku Kim,Hyuk Song,Jae-Wook Oh,Jin-Hoi Kim
Journal of Biomedicine and Biotechnology , 2011, DOI: 10.1155/2011/560850
Abstract: We examined whether deficiency of the GGTA1 gene in pigs altered the expression of several glycosyltransferase genes. Real-time RT-PCR and glycosyltransferase activity showed that 2 sialyltransferases [α2,3-sialyltransferase (α2,3ST) and α2,6-sialyltransferase (α2,6ST)] in the heterozygote GalT KO liver have higher expression levels and activities compared to controls. Enzyme-linked lectin assays indicated that there were also more sialic acid-containing glycoconjugate epitopes in GalT KO livers than in controls. The elevated level of sialic-acid-containing glycoconjugate epitopes was due to the low level of α-Gal in heterozygote GalT KO livers. Furthermore, proteomics analysis showed that heterozygote GalT KO pigs had a higher expression of NAD
Area spectra versus entropy spectra in black holes in topologically massive gravity
Yongjoon Kwon,Soonkeon Nam
Physics , 2010, DOI: 10.1088/0264-9381/27/16/165011
Abstract: We consider the area and entropy spectra of black holes in topologically massive gravity with gravitational Chern-Simons term. The examples we consider are the BTZ black hole and the warped AdS black hole. For the non-rotating BTZ black hole, the area and entropy spectra are equally spaced and independent of the coupling constant $\v$ of the Chern-Simons term. For the rotating BTZ black hole case, the spectra of the inner and outer horizon areas are not equally spaced in general and dependent of the coupling constant $\v$. However the entropy spectrum is equally spaced and independent of the coupling constant $\v$. For the warped AdS black holes for $\v >1$ by using the quasinormal modes obtained without imposing the boundary condition at radial infinity we find again that the entropy spectrum is equally spaced and independent of the coupling constant $\v$, while the spectra of the inner and outer horizon areas are not equally spaced and dependent of the coupling constant $\v$. Our result implies that the entropy spectrum has a universal behavior regardless of the presence of the gravitational Chern-Simons term, and therefore it implies that the entropy is more `fundamental' than the horizon area.
Area spectra of the rotating BTZ black hole from quasinormal modes
Yongjoon Kwon,Soonkeon Nam
Physics , 2010, DOI: 10.1088/0264-9381/27/12/125007
Abstract: Following Bekenstein's suggestion that the horizon area of a black hole should be quantized, the discrete spectrum of the horizon area has been investigated in various ways. By considering the quasinormal mode of a black hole, we obtain the transition frequency of the black hole, analogous to the case of a hydrogen atom, in the semiclassical limit. According to Bohr's correspondence principle, this transition frequency at large quantum number is equal to classical oscillation frequency. For the corresponding classical system of periodic motion with this oscillation frequency, an action variable is identified and quantized via Bohr-Sommerfeld quantization, from which the quantized spectrum of the horizon area is obtained. This method can be applied for black holes with discrete quasinormal modes. As an example, we apply the method for the both non-rotating and rotating BTZ black holes and obtain that the spectrum of the horizon area is equally spaced and independent of the cosmological constant for both cases.
Entropy spectra of black holes from resonance modes in scattering by the black holes
Yongjoon Kwon,Soonkeon Nam
Physics , 2011, DOI: 10.1088/0264-9381/28/3/035007
Abstract: Since the Bekenstein's proposal that a black hole has equally spaced area spectrum, the quasinormal modes as the characteristic modes of a black hole have been used in obtaining the horizon area spectrum of the black hole. However, the area spectrum of the Kerr black hole in some previous works was inconsistent with the Bekenstein's proposal. In this paper, noting that black holes can have three types of resonance modes which are quasinormal modes (QNM), total transmission modes (TTM), and total reflection modes (TRM), we propose that all of these modes in highly damped regime should be used in quantizing the black hole. Although the QNM and the TTM of the Kerr black hole give us complicated quantization conditions from the Bohr-Sommerfeld quantization of action variable, we find a very simple result from the TRM. It gives equally spaced outer horizon area. Therefore by Bekenstein-Hawking area law we find that the Kerr black hole has universal behavior of the equally spaced entropy spectrum. With the same argument, we find that the Reissner-Nordstrom black hole also has equally spaced entropy spectrum.
Quantization of horizon areas of the Kerr black hole
Yongjoon Kwon,Soonkeon Nam
Physics , 2010,
Abstract: Since the Bekenstein's proposal that a black hole has equally spaced area spectrum, the quasinormal modes as the characteristic modes of a black hole have been used in obtaining the horizon area spectrum of the black hole. However, the area spectrum of the Kerr black hole in some previous works was inconsistent with the Bekenstein's proposal. In this paper, we notice that the Kerr black hole has three types of resonance modes which are quasinormal modes (QNM), total transmission modes (TTM), and total reflection modes (TRM). All of these resonances represent highly damped oscillations and only depend on the black hole parameters which are mass, charge and angular momentum of the black hole. We propose that all of these modes should be used in quantizing the black hole. With all these modes, we find that both the inner and outer horizon areas of the Kerr black hole are equally spaced. Similar behavior is also found in the Reissner-Nordstrom black hole.
Effects of Enhanced Digestive Enzymes Activity with Starch and Glycogen During Rotifer Brachionus rotundiformis Culture
O. Nam Kwon,Heum-Gi Park
Journal of Aquaculture Feed Science and Nutrition , 2012, DOI: 10.3923/joafsnu.2012.27.33
Abstract: The purpose of this study was to identify the digestive enzymes activity of rotifer Brachionus rotundiformis enhanced by poly-saccharides added in medium and lipid classes and fatty acids changed after their enrichment. Population growth of rotifer showed significantly higher density in additive trials (starch and glycogen) than non-addition (control) (p<0.05). The activity assayed significantly higher amylase and Total Alkaline Protease (TAP) in additive trials than control after culture (p<0.05). But, TG-lipase activity was significantly higher starch trial only than control after culture and enrichment (p<0.05). Total lipid contents analyzed to significantly higher 9.39% in starch trial only than control after enrichment (p<0.05). Free fatty acid and sterol contents showed significantly higher in additive trials than control after culture and enrichment (p<0.05). Unsaturated fatty acid index (UI) analyzed to significantly higher 227.6-236.6 in additive trials than 205.1 of control (p<0.05). DHA content was higher 15.3-16.7% in additive trials than 13.1% of control after enrichment (p<0.05). Therefore, researchers saw a possibility to raise sterol content that precursor of useful ingredient as several enzyme and hormone. And researchers could be confirmed the lipid utility increased of fish larvae by raising UI by use of starch and glycogen used in the study.
Stretchable Strain Sensors Fabricated by Screen Printing of Silver Paste on the Surface Modified Transparent Elastomeric Polyurethane Films  [PDF]
Chang Gyu Lee, Bo Seok Kwon, Hyun Min Nam, Duck Min Seo, Jinwoo Park, Hyuc Hwangbo, Lee Soon Park, Su Yong Nam
Materials Sciences and Applications (MSA) , 2018, DOI: 10.4236/msa.2018.913073
Abstract: Strain sensors for human-motion detection must offer high stretchability, high sensitivity, fast response, and high recovery speed. In this study, we choose silver paste as a sensing material and use a screen printing method to fabricate the strain sensor based upon an electrical-resistance mechanism. After curing elastomeric polyurethane film with a thickness of 150 μm on PET film, the polyester resin mixed with blocked isocyanate curing agent was coated as a masking layer to reduce the film’s stickiness. The effect of the polyester masking layer upon the silver paste screen printing process was examined using a rolling-ball-tack test, TGA analysis of polyester resins, and cured silver-electrode films. The cost-effective strain sensor fabricated by using silver paste and screen printing processes on the stretchable-polyurethane-substrate film showed high sensitivity and fast response in a strain range of up to 100%.
Potential antitumor effects of nitrogen-containing bisphosphonate in hormone receptor negative breast cancer patients with bone metastases
In Park, Jungsil Ro, Byung Nam, Youngmi Kwon, Keun Lee
BMC Cancer , 2009, DOI: 10.1186/1471-2407-9-154
Abstract: Of 317 patients with initial bone metastasis and known breast cancer subtypes, 230 patients (72.6%) had hormone receptor (HR) positive tumors, and 87 patients (27.4%) had HR negative tumors. We assessed the primary outcome of overall survival (OS), after adjusting for other factors, comparing a group that received bisphosphonates (BPs) with a group that did not receive it.87.8% of HR positive and 69.0% of HR negative patients received BPs with a median number of 17.7 cycles. Although BPs treatment made no survival benefit in HR positive group, HR negative patients showed a significant prolonged survival when they received BPs treatment (hazard ratio = 0.56 [95% CI 0.34 to 0.91], P = 0.019). In multivariate analysis, disease free interval > 2 years (P = 0.036), a sum of metastatic sites < 3 (P = 0.034), and BP treatments (P = 0.007) were significant factors for survival in HR negative patients.Bisphosphonate treatment can result in a survival benefit in metastatic breast cancer patients with HR negative tumors.Bone metastases are common in patients with advanced breast cancer. The median survival time after the diagnosis of bone metastases is approximately two years, although it may increase with new treatment regimens [1]. As patients survive longer, the incidence of associated problems with metastatic bone disease (MBD), such as pathologic fracture or spinal cord compression, increases, and these complications may substantially reduce a patient's quality of life [1,2]. Over the past decade, bisphosphonates (BPs) have become the standard therapy for breast cancer patients with bone metastasis. It is now clear that the bisphosphonates reduce both the symptoms and complications of bone involvement [3]. In addition, the anti-tumor activities of BPs have been explored, particularly with zoledronate and pamidronate, through in-vitro as well as in-vivo animal studies [4-6]. These preclinical studies showed that BPs could reduce visceral metastasis as well as bone metastas
5-Amino-1,3,4-thiadiazol-2(3H)-one
Sung Kwon Kang,Nam Sook Cho,Siyoung Jang
Acta Crystallographica Section E , 2012, DOI: 10.1107/s1600536812012433
Abstract: The asymmetric unit of the title compound, C2H3N3OS, contains three independent molecules which are essentially planar, with r.m.s. deviations of 0.011 (2)–0.027 (2) from the mean plane defined by the seven non-H atoms. In the crystal, N—H...N and N—H...O hydrogen bonds link the molecules into a sheet parallel to the (111) plane.
N-(5-Ethoxy-1,3,4-thiadiazol-2-yl)benzamide
Sung Kwon Kang,Nam Sook Cho,Min Kyeong Jeon
Acta Crystallographica Section E , 2012, DOI: 10.1107/s1600536812002978
Abstract: In the title compound, C11H11N3O2S, the dihedral angle between the thiadiazole and phenyl rings is 28.08 (7)°. In the crystal, molecules are linked into an inversion dimer by a pair of intermolecular N—H...N hydrogen bonds with an R22(8) graph-set motif.
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