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Search Results: 1 - 10 of 27380 matches for " Sang Youl Lee "
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Applying Lipson's state models to marked graph diagrams of surface-links
Yewon Joung,Seiichi Kamada,Sang Youl Lee
Mathematics , 2014,
Abstract: A. S. Lipson constructed two state models yielding the same classical link invariant obtained from the Kauffman polynomial $F(a,z)$. In this paper, we apply Lipson's state models to marked graph diagrams of surface-links, and observe when they induce surface-link invariants.
Crossing number of an alternating knot and canonical genus of its Whitehead double
Hee Jeong Jang,Sang Youl Lee
Mathematics , 2014,
Abstract: A conjecture proposed by J. Tripp in 2002 states that the crossing number of any knot coincides with the canonical genus of its Whitehead double. In the meantime, it has been established that this conjecture is true for a large class of alternating knots including $(2, n)$ torus knots, $2$-bridge knots, algebraic alternating knots, and alternating pretzel knots. In this paper, we prove that the conjecture is not true for any alternating $3$-braid knot which is the connected sum of two torus knots of type $(2, m)$ and $(2, n)$. This results in a new modified conjecture that the crossing number of any prime knot coincides with the canonical genus of its Whitehead double. We also give a new large class of prime alternating knots satisfying the conjecture, including all prime alternating $3$-braid knots.
Computations of quandle cocyle invariants of surface-links using marked graph diagrams
Seiichi Kamada,Jieon Kim,Sang Youl Lee
Mathematics , 2015,
Abstract: By using the cohomology theory of quandles, quandle cocycle invariants and shadow quandle cocycle invariants are defined for oriented links and surface-links via broken surface diagrams. By using symmetric quandles, symmetric quandle cocycle invariants are also defined for unoriented links and surface-links via broken surface diagrams. A marked graph diagram is a link diagram possibly with $4$-valent vertices equipped with markers. S. J. Lomonaco, Jr. and K. Yoshikawa introduced a method of describing surface-links by using marked graph diagrams. In this paper, we give interpretations of these quandle cocycle invariants in terms of marked graph diagrams, and introduce a method of computing them from marked graph diagrams.
The canonical genus for Whitehead doubles of a family of alternating knots
Hee Jeong Jang,Sang Youl Lee
Mathematics , 2011,
Abstract: For any given integer $r \geq 1$ and a quasitoric braid $\beta_r=(\sigma_r^{-\epsilon} \sigma_{r-1}^{\epsilon}...$ $ \sigma_{1}^{(-1)^{r}\epsilon})^3$ with $\epsilon=\pm 1$, we prove that the maximum degree in $z$ of the HOMFLYPT polynomial $P_{W_2(\hat\beta_r)}(v,z)$ of the doubled link $W_2(\hat\beta_r)$ of the closure $\hat\beta_r$ is equal to $6r-1$. As an application, we give a family $\mathcal K^3$ of alternating knots, including $(2,n)$ torus knots, 2-bridge knots and alternating pretzel knots as its subfamilies, such that the minimal crossing number of any alternating knot in $\mathcal K^3$ coincides with the canonical genus of its Whitehead double. Consequently, we give a new family $\mathcal K^3$ of alternating knots for which Tripp's conjecture holds.
On generating sets of Yoshikawa moves for marked graph diagrams of surface-links
Jieon Kim,Yewon Joung,Sang Youl Lee
Mathematics , 2014,
Abstract: A marked graph diagram is a link diagram possibly with marked $4$-valent vertices. S. J. Lomonaco, Jr. and K. Yoshikawa introduced a method of representing surface-links by marked graph diagrams. Specially, K. Yoshikawa gave local moves on marked graph diagrams, nowadays called Yoshikawa moves. It is now known that two marked graph diagrams representing equivalent surface-links are related by a finite sequence of these Yoshikawa moves. In this paper, we provide some generating sets of Yoshikawa moves on marked graph diagrams representing unoriented surface-links, and also oriented surface-links. We also discuss independence of certain Yoshikawa moves from the other moves.
Amphiphilic Block Copolymer for adsorption of Organic Contaminants  [PDF]
Jae-Woo Choi, Kyung-Youl Baek, Kie-Yong Cho, Natalia Valer’yevna Shim, Sang-Hyup Lee
Advances in Chemical Engineering and Science (ACES) , 2011, DOI: 10.4236/aces.2011.12013
Abstract: In this study, new polymeric adsorbents, 2 types of polystyrene-block-poly (N-isopropylacrylamide) (PSN, structure of hydrophobic core and hydrophilic shell), were developed and applied for removal of organic pollutants from wastewater. Encapsulation of organic pollutants by the polystyrene-block-poly (N-isopropylacrylamide) (PSN) resulted in increasing hydrophobicity of the polystyrene with abundant hydrophobic spaces within the amphiphilic block copolymer. The encapsulation mechanism of BTEX by PSN was investigated and found to be mainly attributable to the Van der Waals interactions between the aromatic ring of BTEX and the hydrophobic core of PSN. Polystyrene-block-poly (N-isopropylacrylamide) showed good potential as a novel and cost effective adsorbent for application to wastewater treatment, which can be simply regenerated and reused using an external temperature changing system.
Effect of GCSB-5, a Herbal Formulation, on Monosodium Iodoacetate-Induced Osteoarthritis in Rats
Joon-Ki Kim,Sang-Won Park,Jung-Woo Kang,Yu-Jin Kim,Sung Youl Lee,Joonshik Shin,Sangho Lee,Sun-Mee Lee
Evidence-Based Complementary and Alternative Medicine , 2012, DOI: 10.1155/2012/730907
Abstract: Therapeutic effects of GCSB-5 on osteoarthritis were measured by the amount of glycosaminoglycan in rabbit articular cartilage explants in vitro, in experimental osteoarthritis induced by intra-articular injection of monoiodoacetate in rats in vivo. GCSB-5 was orally administered for 28 days. In vitro, GCSB-5 inhibited proteoglycan degradation. GCSB-5 significantly suppressed the histological changes in monoiodoacetate-induced osteoarthritis. Matrix metalloproteinase (MMP) activity, as well as, the levels of serum tumor necrosis factor-α, cyclooxygenase-2, inducible nitric oxide synthase protein, and mRNA expressions were attenuated by GCSB-5, whereas the level of interleukin-10 was potentiated. By GCSB-5, the level of nuclear factor-κB p65 protein expression was significantly attenuated but, on the other hand, the level of inhibitor of κB-α protein expression was increased. These results indicate that GCSB-5 is a potential therapeutic agent for the protection of articular cartilage against progression of osteoarthritis through inhibition of MMPs activity, inflammatory mediators, and NF-κB activation.
Kaempferol and Kaempferol Rhamnosides with Depigmenting and Anti-Inflammatory Properties
Ho Sik Rho,Amal Kumar Ghimeray,Dae Sung Yoo,Soo Mi Ahn,Sun Sang Kwon,Keun Ha Lee,Dong Ha Cho,Jae Youl Cho
Molecules , 2011, DOI: 10.3390/molecules16043338
Abstract: The objective of this study was to examine the biological activity of kaempferol and its rhamnosides. We isolated kaempferol (1), a-rhamnoisorobin (2), afzelin (3), and kaempferitrin (4) as pure compounds by far-infrared (FIR) irradiation of kenaf (Hibiscus cannabinus L.) leaves. The depigmenting and anti-inflammatory activity of the compounds was evaluated by analyzing their structure-activity relationships. The order of the inhibitory activity with regard to depigmentation and nitric oxide (NO) production was kaempferol (1) > a-rhamnoisorobin (2) > afzelin (3) > kaempferitrin (4). However, a-rhamnoisorobin (2) was more potent than kaempferol (1) in NF-kB-mediated luciferase assays. From these results, we conclude that the 3-hydroxyl group of kaempferol is an important pharmacophore and that additional rhamnose moieties affect the biological activity negatively.
Development of an HbA1c-Based Conversion Equation for Estimating Glycated Albumin in a Korean Population with a Wide Range of Glucose Intolerance
Chang Hee Jung, You-Cheol Hwang, Kwang Joon Kim, Bong Soo Cha, Cheol-Young Park, Won Seon Jeon, Jae Hyeon Kim, Sang-Man Jin, Sang Youl Rhee, Jeong-taek Woo, Byung-Wan Lee
PLOS ONE , 2014, DOI: 10.1371/journal.pone.0095729
Abstract: Background Compared to the golden standard glycation index of HbA1c, glycated albumin (GA) has potentials for assessing insulin secretory dysfunction and glycemic fluctuation as well as predicting diabetic vascular complications. However, the reference ranges of GA and a conversion equation need to be clearly defined. We designed this study to determine the reference ranges in patients with normal glucose tolerance (NGT) based on conventional measures of glycemic status and to devise a conversion equation for calculating HbA1c and GA in a Korean population. Methodology/Principal Findings In this multicenter, retrospective, cross-sectional study, we recruited antidiabetic drug-na?ve patients with available glycemic variables including HbA1c, GA, and fasting plasma glucose regardless of glucose status. For the reference interval of serum GA, 5th to 95th percentile value of GA in subjects with NGT was adopted. The conversion equation between HbA1c and GA was devised using an estimating regression model with unknown break-points method. The reference range for GA was 9.0–14.0% in 2043 subjects. The 95th percentile responding values for FPG, and HbA1c were approximately 5.49 mmol/l, and 5.6%, respectively. The significant glycemic turning points were 5.868% HbA1c and 12.2% GA. The proposed conversion equation for below and above the turning point were GA (%) = 6.960+0.8963 × HbA1c (%) and GA (%) = ?9.609+3.720 × HbA1c (%), respectively. Conclusions/Significance These results should be helpful in future studies on the clinical implications of high GA relative to HbA1c and the clinical implementation of diabetes management.
A Case of Possible Neurosarcoidosis Presenting as Intractable Headache and Panhypopituitarism
Jin Kyung Hwang,Joo Hee Cho,So Young Park,Jung Il Son,Uk Jo,Sang Ouk Chin,Yun Jung Lee,Moon Chan Choi,Sang Youl Rhee,Eui Jong Kim,Suk Chon
Case Reports in Endocrinology , 2013, DOI: 10.1155/2013/816236
Abstract: Sarcoidosis is a chronic multisystemic inflammatory disease of unknown etiology, which is characterized by noncaseating granulomatous inflammation of the involved organs. It is known that neurosarcoidosis involving the nervous system occurs in about 5% of patients with sarcoidosis. However, neurosarcoidosis without systemic involvement is extremely rare. We present a case of suspicious neurosarcoidosis affecting the pituitary gland, which was manifested as chronic uncontrolled headache, panhypopituitarism, central diabetes insipidus, and hypercalcemia. Though the biopsy at the pituitary lesion was not performed due to the high risk of surgical complication, treatment was needed urgently and we started steroid therapy. After steroid therapy, we observed the immediate symptom relief with improved hypercalcemia. According to the follow-up examination, no recurrent symptom was seen, and resolution of the pituitary lesion with improving panhypopituitarism was noted. 1. Introduction Sarcoidosis is a noncaseating granulomatous disease that can affect any system of the body [1]. Neurosarcoidosis involves the nervous system and occurs in less than 5% of patients with systemic sarcoidosis. Isolated neurosarcoidosis without systemic involvement is extremely rare [2]. We describe a case of possible neurosarcoidosis of the pituitary gland without any other systemic involvement. The patient presented with panhypopituitarism, central diabetes insipidus, and hypercalcemia. Sellar magnetic resonance imaging (MRI) showed an infiltrating mass of the pituitary gland with invasion of stalk and cavernous sinus. Steroid therapy resulted in the resolution of the pituitary lesion on sellar MRI and all symptoms. 2. Case Presentation A 39-year-old man presented to our clinic with nausea and headache. He reported that these symptoms had waxed and waned for five years and were aggravated for three weeks before admission. His medical history revealed that he had been diagnosed with a pituitary microadenoma at the age of thirty four with symptoms of polyuria, polydipsia, and severe headache. Initial sellar MRI showed a pituitary microadenoma with stalk deviation and thickening (Figure 1(a)). An anterior pituitary function test revealed minimal elevation of prolactin (20.2?ng/mL) with no other significant abnormalities. He began to take lisuride hydrogen maleate, which decreased his serum prolactin level. Although intranasal vasopressin therapy significantly relieved the polyuria and polydipsia, his headache did not subside, and, thus, intermittent low-dose steroid therapy was
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