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Search Results: 1 - 10 of 20463 matches for " Eunhee Kim "
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Estimation of Biochemical Oxygen Demand Based on Dissolved Organic Carbon, UV Absorption, and Fluorescence Measurements
Jihyun Kwak,Bumju Khang,Eunhee Kim,Hyunook Kim
Journal of Chemistry , 2013, DOI: 10.1155/2013/243769
Abstract:
A role for spleen monocytes in post-ischemic brain inflammation and injury
Yi Bao, Eunhee Kim, Sangram Bhosle, Heeral Mehta, Sunghee Cho
Journal of Neuroinflammation , 2010, DOI: 10.1186/1742-2094-7-92
Abstract: Ischemia-reperfusion causes inflammation that attracts monocyte/macrophage cells to infarct [1-3]. Monocytes are circulating antigen-presenting leukocytes that play an important role in inflammation, T-cell differentiation, phagocytosis, and innate immunity [4,5]. It has been shown that circulating and spleen monocytes are similar in their morphology, phagocytic capability, and gene expression profiles [6]. The study also identified the spleen as a monocyte reservoir and their numbers in the spleen are several folds higher than in circulation [6]. In addition, the number of monocytes that migrate to the infarct area after a myocardial infarction well exceeds the number in circulation under homeostatic conditions [4]. These studies suggest a potential role of the spleen in deploying monocytes upon cerebral ischemia.Human and mouse monocytes exhibit distinct subsets that are reminiscent of macrophage phenotypes [5,7,8]. In mice, the subset that expresses a high level of the hematopoietic cell differentiation antigen Ly-6C (Ly-6Chi) also expresses the G-protein linked membrane protein, CCR2. The Ly-6Chi/CCR2+ monocyte subset is specifically recruited to an injury site by monocyte chemoattractant protein-1 (MCP-1), which is produced by the inflamed tissue, and become classically activated M1 macrophages. In contrast, the Ly-6Clow monocyte subset expresses CX3CR1, a receptor for the chemokine CX3CL1 (fractalkine), but is devoid of CCR2 expression. This anti-inflammatory Ly-6Clow/CCR2-/CX3CR1+ subset is recruited to normal tissue and develops into resident M2 macrophages that function in host defense and repair after injury [9,10]. Recruitment of the pro-inflammatory Ly-6Chi/CCR2+ subset to inflammatory sites is believed to be CCR2-dependent, since monocytes from CCR2-null mice do not traffic as efficiently into a myocardial infarct as CCR2+ monocytes [6]. Furthermore, CCR2-null mice were protective against cerebral inflammation following ischemia [11], suggesting that CC
Mining the Minds of Customers from Online Chat Logs
Kunwoo Park,Jaewoo Kim,Jaram Park,Meeyoung Cha,Jiin Nam,Seunghyun Yoon,Eunhee Rhim
Computer Science , 2015,
Abstract: This study investigates factors that may determine satisfaction in customer service operations. We utilized more than 170,000 online chat sessions between customers and agents to identify characteristics of chat sessions that incurred dissatisfying experience. Quantitative data analysis suggests that sentiments or moods conveyed in online conversation are the most predictive factor of perceived satisfaction. Conversely, other session related meta data (such as that length, time of day, and response time) has a weaker correlation with user satisfaction. Knowing in advance what can predict satisfaction allows customer service staffs to identify potential weaknesses and improve the quality of service for better customer experience.
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
Iron deposition and increased alveolar septal capillary density in nonfibrotic lung tissue are associated with pulmonary hypertension in idiopathic pulmonary fibrosis
Kyung-Hee Kim, Fabien Maldonado, Jay H Ryu, Patrick W Eiken, Thomas E Hartman, Brian J Bartholmai, Paul A Decker, Eunhee S Yi
Respiratory Research , 2010, DOI: 10.1186/1465-9921-11-37
Abstract: Iron deposition and alveolar septal capillary density (ASCD) were evaluated on histologic sections with hematoxylin-eosin, iron, elastin and CD34 stainings. Percentage of predicted forced vital capacity (FVC%) was used for grading pulmonary function status. Fibrosis score assessed on high resolution computed tomography (HRCT) was used for evaluating overall degree of fibrosis in whole lungs. Right ventricular systolic pressure (RVSP) by transthoracic echocardiography was used for the estimation of PH. Univariate and multivariate regression analyses were performed.A cohort of 154 patients was studied who had the clinicopathological diagnosis of IPF with surgical lung biopsies or explants during the period of 1997 to 2006 at Mayo Clinic Rochester. In univariate analysis, RVSP in our IPF cases was associated with both iron deposition and ASCD (p < 0.001). In multivariate analysis with FVC% and HRCT fibrosis score included, iron deposition (p = 0.02), but not ASCD (p = 0.076), maintained statistically significant association with RVSP. FVC% was associated with RVSP on univariate analysis but not on multivariate analysis, while fibrosis score lacked any association with RVSP by either univariate or multivariate analyses.Iron deposition and ASCD in non fibrotic lung tissue showed an association with RVSP, suggesting that these features are possible morphologic predictors of PH in IPF.Idiopathic pulmonary fibrosis (IPF) is characterized by a histopathologic pattern of usual interstitial pneumonia (UIP) and progressive fibrosis without response to medical therapy [1]. However, clinical course of IPF is not always predictable despite its generally poor prognosis [2]. Pulmonary hypertension (PH) has been postulated to be a factor that might complicate and impact the prognosis of IPF [3]. Also, the therapeutic agents for PH might be effective for those who have PH with IPF.Early diagnosis of PH in IPF is difficult; lack of specific clinical symptoms often leads to delayed diag
Growth of ZnO Nanorod Arrays on Flexible Substrates: Effect of Precursor Solution Concentration
Fei Tong,Kyusang Kim,Yaqi Wang,Resham Thapa,Yogesh Sharma,Aaron Modic,Ayayi Claude Ahyi,Tamara Issacs-Smith,John Williams,Hosang Ahn,Hyejin Park,Dong-Joo Kim,Sungkoo Lee,Eunhee Lim,Kyeong K. Lee,Minseo Park
ISRN Nanomaterials , 2012, DOI: 10.5402/2012/651468
Abstract: We report a low-temperature aqueous solution growth of uniformly aligned ZnO nanorod arrays on flexible substrates. The substrate is Indium Tin Oxide (ITO) film coated on polyethylene terephthalate (PET). Solutions with five different concentrations of the precursors with equimolar Zinc Nitrate and Hexamethylenetetramine (HMT) in distilled water were prepared to systematically study the effect of precursor solution concentration on the structural and optical properties of ZnO nanorods. It was concluded that the precursor concentration have great influence on the morphology, crystal quality, and optical property of ZnO nanorods. The diameter, density, and orientation of the nanorods are dependent on the precursor solution concentration. X-ray diffraction and micro-Raman spectroscopy showed that the ZnO nanorods with the highest concentration of 50?mM were highly aligned and have the highest level of surface coverage. It was also found that the diameter and length of the nanorods increases upon increasing precursor solution concentration. This is the first systematic investigation of studying the effect of precursor solution concentration on the quality of ZnO nanorods grown on ITO/PET substrates by low-temperature solution method. We believe that our work will contribute to the realization of flexible organic-inorganic hybrid solar cell based on ZnO nanorods and conjugated polymer. 1. Introduction Zinc oxide (ZnO) is a semiconductor with a wide direct band gap of 3.37?eV and a large exciton binding energy of 60?meV, which makes the material useful for optoelectronic application [1, 2]. Nanostructures of ZnO such as ZnO nanorods and nanowires have received increased attention due to their excellent electrical and optical properties [3]. Due to the high surface-to-volume ratio provided by the one-dimensional (1D) nanostructure, ZnO nanorod arrays are considered suitable to the application for hybrid photovoltaic devices [4–7]. In the past few years, ZnO nanorods have been synthesized via various physical and chemical methods including vapor phase synthesis [8–10], metalorganic chemical vapor deposition (MOCVD) [11–13], and solution-based synthesis [14–17]. Among these routes, solution-based method has the advantages of simplicity, low costs, low growth temperature, and easy coating of large surfaces Intensive research has been focused on the solution growth process of ZnO nanorods on ITO-coated glass substrates. Guo et al. [18] have systematically studied the effect of processing conditions such as pretreatment of the substrates, growth temperature,
Distinct Cardiac Transcriptional Profiles Defining Pregnancy and Exercise
Eunhee Chung, Joseph Heimiller, Leslie A. Leinwand
PLOS ONE , 2012, DOI: 10.1371/journal.pone.0042297
Abstract: Background Although the hypertrophic responses of the heart to pregnancy and exercise are both considered to be physiological processes, they occur in quite different hormonal and temporal settings. In this study, we have compared the global transcriptional profiles of left ventricular tissues at various time points during the progression of hypertrophy in exercise and pregnancy. Methodology/Principal Findings The following groups of female mice were analyzed: non-pregnant diestrus cycle sedentary control, mid-pregnant, late-pregnant, and immediate-postpartum, and animals subjected to 7 and 21 days of voluntary wheel running. Hierarchical clustering analysis shows that while mid-pregnancy and both exercise groups share the closest relationship and similar gene ontology categories, late pregnancy and immediate post-partum are quite different with high representation of secreted/extracellular matrix-related genes. Moreover, pathway-oriented ontological analysis shows that metabolism regulated by cytochrome P450 and chemokine pathways are the most significant signaling pathways regulated in late pregnancy and immediate-postpartum, respectively. Finally, increases in expression of components of the proteasome observed in both mid-pregnancy and immediate-postpartum also result in enhanced proteasome activity. Interestingly, the gene expression profiles did not correlate with the degree of cardiac hypertrophy observed in the animal groups, suggesting that distinct pathways are employed to achieve similar amounts of cardiac hypertrophy. Conclusions/Significance Our results demonstrate that cardiac adaptation to the later stages of pregnancy is quite distinct from both mid-pregnancy and exercise. Furthermore, it is very dynamic since, by 12 hours post-partum, the heart has already initiated regression of cardiac growth, and 50 genes have changed expression significantly in the immediate-postpartum compared to late-pregnancy. Thus, pregnancy-induced cardiac hypertrophy is a more complex process than exercise-induced cardiac hypertrophy and our data suggest that the mechanisms underlying the two types of hypertrophy have limited overlap.
Uniform Sobolev inequalities for second order non-elliptic differential operators
Eunhee Jeong,Yehyun Kwon,Sanghyuk Lee
Mathematics , 2015,
Abstract: We study uniform Sobolev inequalities for the second order differential operators $P(D)$ of non-elliptic type. For $d\ge3$ we prove that the Sobolev type estimate $\|u\|_{L^q(\mathbb{R}^d)}\le C \|P(D)u\|_{L^p(\mathbb{R}^d)}$ holds with $C$ independent of the first order and the constant terms of $P(D)$ if and only if $1/p-1/q=2/d$ and $\frac{2d(d-1)}{d^2+2d-4}
Spectrum of Disorders Associated with Elevated Serum IgG4 Levels Encountered in Clinical Practice
Jay H. Ryu,Ryohei Horie,Hiroshi Sekiguchi,Tobias Peikert,Eunhee S. Yi
International Journal of Rheumatology , 2012, DOI: 10.1155/2012/232960
Abstract: IgG4-related disease (IgG4-RD) is a recently described systemic fibroinflammatory disease associated with elevated circulating levels of IgG4 and manifests a wide spectrum of clinical presentations. Although serum IgG4 level has been described to be the most sensitive and specific laboratory test for the diagnosis of IgG4-RD, it is recognized that an elevated serum IgG4 level can be encountered in other diseases. In this study, we sought to identify the frequency of IgG4-RD and other disease associations in patients with elevated serum IgG4 levels seen in clinical practice. Among 3,300 patients who underwent IgG subclass testing over a 2-year period from January 2009 to December 2010, 158 (4.8%) had an elevated serum IgG4 level (>140?mg/dL). IgG4 subclass testing was performed for evaluation of suspected IgG4-RD or immunodeficiency. Twenty-nine patients (18.4%) had definite or possible IgG4-RD. Among those patients without IgG4-RD, a broad spectrum of biliary tract, pancreatic, liver, and lung diseases, as well as systemic vasculitis, was diagnosed. We conclude that patients with elevated serum IgG4 levels encountered in clinical practice manifest a wide array of disorders, and only a small minority of them has IgG4-RD. 1. Introduction IgG4-related disease (IgG4-RD) is a recently described systemic fibroinflammatory disease associated with elevated circulating levels of IgG4 [1–4]. The pathologic lesion of IgG4-RD is characterized by lymphoplasmacytic inflammation with increased numbers of IgG4-positive plasma cells, fibrosis, and phlebitis. Although initial descriptions of this disorder focused on its pancreatic presentation (autoimmune pancreatitis), it has become apparent that IgG4-RD is a systemic disease associated with a wide spectrum of clinical manifestations involving virtually any organ in the body. As initially observed in patients with autoimmune pancreatitis, the majority of patients with IgG4-RD have an elevated serum IgG4 level. Although serum IgG4 level has been described to be the most sensitive and specific laboratory test for the diagnosis of IgG4-RD, it is recognized that an elevated serum IgG4 level can be encountered in other diseases such as pancreatic cancer [5], atopic diseases [6], and infections [7, 8]. Furthermore, serum IgG4 level is elevated in up to 5% of the normal population [9, 10]. In this study, we sought to identify the spectrum of diseases associated with elevated serum IgG4 levels in patients encountered in clinical practice and the frequency of IgG4-RD in this population. 2. Methods Using a computer-assisted
Increased IgG4-Positive Plasma Cells in Granulomatosis with Polyangiitis: A Diagnostic Pitfall of IgG4-Related Disease
Sing Yun Chang,Karina Keogh,Jean E. Lewis,Jay H. Ryu,Eunhee S. Yi
International Journal of Rheumatology , 2012, DOI: 10.1155/2012/121702
Abstract: Granulomatosis with polyangiitis (Wegener’s) (GPA) may mimic IgG4-related disease (IgG4-RD) on histologic examination of some biopsies, especially those from head and neck sites. IgG4 immunostain is often performed in this context for differential diagnosis with IgG4-RD. However, the prevalence of IgG4+ cells in GPA has not been explored. We examined the IgG4+ cells in 26 cases confirmed as GPA by a thorough clinical and pathologic assessment. Twenty-six biopsies consisted of 14 sinonasal/oral cavity/nasopharynx, 7 orbit/periorbital, 3 lung/pleura, 1 iliac fossa/kidney, and 1 dura specimens. Eight of 26 (31%) biopsies revealed increased IgG4+ cells (>30/HPF and >40% in IgG4+/IgG+ ratio). The IgG4+ cells and IgG4+/IgG+ ratio ranged 37–137/hpf and 44–83%, respectively. Eight biopsies with increased IgG4+ cells were from sinonasal or orbital/periorbital sites. In conclusion, increased IgG4+ cells are not uncommonly seen in sinonasal or orbital/periorbital biopsies of GPA, which could pose as a diagnostic pitfall. 1. Introduction Granulomatosis with polyangiitis (Wegener’s) (GPA) is an immune-mediated systemic necrotizing vasculitis often affecting the upper respiratory tract, lung, and kidney [1]. Involvement of GPA is limited to the upper respiratory tract and/or the lung in some cases although virtually anybody site can be involved in GPA such as the eye, skin, joints, heart, and the central nervous system [2]. Necrotizing vasculitis and irregular basophilic parenchymal necrosis with associated palisading granuloma comprise the main histologic characteristics of GPA. Also, neutrophilic microabscesses and fibrosis are commonly found in a background mixed inflammatory infiltrate composed of neutrophils, lymphocytes, plasma cells, multinucleated giant cells, and macrophages [1, 2]. On histologic examination, GPA can mimic IgG4-related disease (IgG4-RD) since the inflammatory background in GPA may be rich in plasma cells and accompanied by fibrosis and/or obliterated blood vessels as in IgG4-RD [1, 3, 4]. Some biopsies of GPA cases (especially from the upper respiratory tract and orbit) may lack classic morphologic features such as necrotizing vasculitis, parenchymal necrosis, and palisading granuloma [5, 6]. IgG4 immunostain is now often performed in this context for evaluating the possibility of IgG4-RD. However, the prevalence of IgG4-positive (IgG4+) cells in GPA has not been widely reported in the literature. Therefore, we sought to assess the prevalence of IgG4+ cells in GPA cases that have been confirmed by a thorough clinical and pathologic
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