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Search Results: 1 - 10 of 11595 matches for " Sung Woo Park "
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Structural Analysis of Hypothetical Proteins from Helicobacter pylori: An Approach to Estimate Functions of Unknown or Hypothetical Proteins
Sung Jean Park,Woo Sung Son,Bong-Jin Lee
International Journal of Molecular Sciences , 2012, DOI: 10.3390/ijms13067109
Abstract: Helicobacter pylori ( H. pylori) have a unique ability to survive in extreme acidic environments and to colonize the gastric mucosa. It can cause diverse gastric diseases such as peptic ulcers, chronic gastritis, mucosa-associated lymphoid tissue (MALT) lymphoma, gastric cancer, etc. Based on genomic research of H. pylori, over 1600 genes have been functionally identified so far. However, H. pylori possess some genes that are uncharacterized since: (i) the gene sequences are quite new; (ii) the function of genes have not been characterized in any other bacterial systems; and (iii) sometimes, the protein that is classified into a known protein based on the sequence homology shows some functional ambiguity, which raises questions about the function of the protein produced in H. pylori. Thus, there are still a lot of genes to be biologically or biochemically characterized to understand the whole picture of gene functions in the bacteria. In this regard, knowledge on the 3D structure of a protein, especially unknown or hypothetical protein, is frequently useful to elucidate the structure-function relationship of the uncharacterized gene product. That is, a structural comparison with known proteins provides valuable information to help predict the cellular functions of hypothetical proteins. Here, we show the 3D structures of some hypothetical proteins determined by NMR spectroscopy and X-ray crystallography as a part of the structural genomics of H. pylori. In addition, we show some successful approaches of elucidating the function of unknown proteins based on their structural information.
Comparison of Protein Profiles in Sputum between COPD and Acute Exacerbation of COPD  [PDF]
Soo-Taek Uh, Seung Ah Ko, An Soo Jang, Sung Woo Park, Yong-Hoon Kim, Young-Ki Paik, Choon Sik Park
Open Journal of Respiratory Diseases (OJRD) , 2012, DOI: 10.4236/ojrd.2012.22004
Abstract: Background and objective: Chronic obstructive pulmonary disease (COPD) is characterized by progressive airflow limitation that is associated with an abnormal inflammatory response of the lung to noxious particles or gases. Cigarette smoking is the major risk factor for the development of COPD. This study evaluated the levels of cyclophilin B in sputa from patients with COPD and COPD with acute exacerbation (AECOPD). Materials and Methods: Two-dimensional electrophoresis was used for differential display proteomics. Western blotting was used to identify and quantify cyclophilin B in sputum from subjects with AECOPD and COPD. Results: Forty-nine protein spots differed in relative intensity between the AECOPD (n = 6) and COPD (n = 6) subjects. Twenty proteins showed increased expression in the sputum of AECOPD subjects, and 29 proteins were present at lower levels in AECOPD sputum compared with COPD sputum. One of these proteins was associated with cyclophilin B. Cyclophilin B concentrations were lower in sputum from subjects with COPD (n = 4) versus AECOPD (n = 4). Conclusion: The sputum proteomic analysis suggests that changes in various proteins are associated with the development of AECOPD.
Cognitive Profiles and Subtypes of Patients with Mild Cognitive Impairment: Data from a Clinical Follow-Up Study  [PDF]
Kyung Won Park, Eun-Joo Kim, Hwan Joo, Sung-Man Jeon, Seong-Ho Choi, Jay C. Kwon, Byoung Gwon Kim, Jae Woo Kim
International Journal of Clinical Medicine (IJCM) , 2012, DOI: 10.4236/ijcm.2012.35068
Abstract: Background: Mild cognitive impairment (MCI) is a heterogeneous condition with a variety of clinical outcomes, the presence of which correlates with risk of Alzheimer’s disease as well as pre-clinical stages of other dementia subtypes. The aims of this study were to assess the specific patterns of cognitive profiles and to identify changes from baseline to 24 weeks in patients with MCI using detailed neuropsychological testing. Methods: We consecutively recruited 120 MCI patients at baseline according to the Petersen’s clinical diagnostic criteria, who were admitted to the Dementia and Memory Clinics. We analyzed patients who fulfilled both inclusion and exclusion criteria for MCI and classified them into four subtypes according to deficits in major cognitive domains; amnestic MCI single domain (aMCI-s), amnestic multiple domain MCI (aMCI-m), non-amnestic single domain MCI (naMCI-s) and non-amnestic multiple domain MCI (naMCI-m). Four groups of MCI were evaluated by a detailed neuropsychological battery test. Results: 83 patients with MCI at the 24-week follow-up were classified into four subtypes. The most frequent subtype was amnestic multi-domain MCI, with the frequency of MCI subtypes as follows: aMCI-s (n = 21, 25.3%), aMCI-m (n = 53, 63.9%), naMCI-s (n = 5, 6.0%) and naMCI-m (n = 4, 4.8%). In the major cognitive items of the SNSB-D, there were significant changes between the initial and follow-up tests in the domains of language, memory and the fron-tal/executive function (p < 0.05), except for attention, in all MCI patient subtypes. At 24-weeks follow-up, the conversion rate to Alzheimer’s disease was 2.4% (n = 2) from a subtype of amnestic multi-domain MCI. Conclusions: Our study revealed the most frequent subtype of MCI to be multiple domain amnestic MCI, with this subtype having a higher tendency of conversion to Alzheimer’s disease.
An Equation to Estimate the Concentration of Serum Apolipoprotein B
You-Cheol Hwang, Hong-Yup Ahn, Woo Je Lee, Cheol-Young Park, Sung-Woo Park
PLOS ONE , 2012, DOI: 10.1371/journal.pone.0051607
Abstract: Background Several large prospective studies have demonstrated that apolipoprotein B (apoB) has greater value in predicting cardiovascular risk than any other lipid measurements. Currently, however, serum apoB levels are not routinely measured, because of the additional cost. The aim of this study was to develop an equation to estimate apoB from conventional lipid measurements including total cholesterol, HDL cholesterol, and triglycerides. Methods Data from a total of 78,127 subjects (47,057 men and 31,070 women), aged 15 to 88 years (mean age 41.8 years) were reviewed to develop an apoB equation. Additional datasets from the same institution and the NHANES obtained in 2007–2008 were used for internal (n = 73,445) and external validation (n = 3,097), respectively. Results We developed an apoB equation based on a linear regression model that contains total cholesterol, triglycerides, and HDL cholesterol as terms (model 1). To more precisely estimate the serum apoB level, we adjusted mode1 1 using a cutoff serum triglyceride value of 270 mg/dl (model 2). Model 2 showed more randomly distributed residuals in patients with diabetes, atherogenic dyslipidemia, and those taking lipid-lowering agents than model 1. The residuals in the development, internal validation, and external validation datasets were also randomly distributed around 0 with no clear trends. Conclusion The new equation we developed to estimate serum apoB concentrations is accurate and can be used in diverse subgroups of patients including those with diabetes, atherogenic dyslipidemia, and those taking lipid-lowering agents.
Behavioral Aspects of Social Network Analysis
Sung Joo Park,Jong Woo Kim,Hong Joo Lee,Hyun Jung Park,Peter Gloor
Computer Science , 2015,
Abstract: Contrary to the structural aspect of conventional social network analysis, a new method in behavioral analysis is proposed. We define behavioral measures including self-loops and multiple links and illustrate the behavioral analysis with the networks of Wikipedia editing. Behavioral social network analysis provides an explanation of human behavior that may be further extended to the explanation of culture through social phenomena.
Frobenius numbers of Pythagorean triples
Byung Keon Gil,Ji-woo Han,Tae Hyun Kim,Ryun Han Koo,Bon Woo Lee,Jaehoon Lee,Kyeong Sik Nam,Hyeon Woo Park,Poo-Sung Park
Mathematics , 2014,
Abstract: Given relatively prime integers $a_1, \dotsc, a_n$, the Frobenius number $g(a_1, \dotsc, a_n)$ is defined as the largest integer which cannot be expressed as $x_1 a_1 + \dotsb + x_n a_n$ with $x_i$ nonnegative integers. In this article, we give the Frobenius number of primitive Pythagorean triples. That is, \[ g(m^2-n^2, 2mn, m^2+n^2) = (m-1)(m^2-n^2) + (m-1)(2mn) - (m^2 + n^2). \]
Incidence and Clinical Characteristics of Deep Vein Thrombosis (DVT) after Total Knee Arthroplasty (TKA) with DVT Chemoprophylaxis  [PDF]
Yong Sung Won, Mihyeong Kim, Kang Woong Jun, Woo Seok Nam, Sanghyun Ahn, Jeong-Kye Hwang, Sang-Dong Kim, Sun-Cheol Park, Sang Seob Yun, Won-Chul Lee, Jang-Sang Park, Jang Yong Kim
World Journal of Cardiovascular Diseases (WJCD) , 2014, DOI: 10.4236/wjcd.2014.411064
Abstract: Objective: Deep vein thrombosis (DVT) after total knee arthroplasty (TKA) is very common and leading cause of death due to this procedure. The objective of this study was to investigate the incidence and clinical characteristics of DVT after TKA with DVT chemoprophylaxis. Methods: This is a prospective cohort study in single institution. The patients received postoperative DVT chemoprophylaxis (low molecular weight heparin (LMWH) or Fondaparinux), followed by duplex ultrasonography to check for DVT 1 - 2 weeks after TKA. The clinical characteristics were summarized and analysed by chi-square test and regression analysis. Results: Five hundred and thirty four patients were enrolled from January 2007 to December 2010. DVT chemoprophylaxis was administered in 524 (98.1%) of the 534 patients. DVT occurred in 9 subjects (1.69%); 8 subjects had DVT in the leg, and 1 subject had a pulmonary embolism. Among them, asymptomatic DVT was observed in 5 patients (0.94%). Univariate analysis showed that surgical methods (revision, P = 0.0007), body mass index (BMI) (>25, P = 0.0028), low platelet count (less than 150 × 103, P = 0.0219), time in the intensive care unit (ICU) (P < 0.0001), no administration of prophylactic LMWH (P = 0.0392), and a history of DVT (P < 0.0001) were significant risk factors of DVT. Conclusions: The incidence of DVT was 1.69% after TKA with prophylactic antithrombotic therapy. Revision surgery, BMI, low platelet count, time in ICU, absence of prophylactic LMWH and history of DVT were significant risk factors of DVT.
Factors Associated With the Time to Next Attack in Neuromyelitis Optica: Accelerated Failure Time Models With Random Effects
Sung-Min Kim, Junwoo Park, Sun Hee Kim, Su-Yeon Park, Jee Young Kim, Jung-Joon Sung, Kyung Seok Park, Kwang-Woo Lee
PLOS ONE , 2013, DOI: 10.1371/journal.pone.0082325
Abstract: Background and Objective Neuromyelitis optica (NMO) is an inflammatory demyelinating disorder of the central nervous system with a relapsing and remitting course. We aimed to identify factors associated with the time to next attack, including the effect of the natural disease course and the diverse treatment regimens, by applying a longitudinal statistical analysis to the individual attacks of each patient. Methods In total, 184 acute attacks among 58 patients with either NMO or NMO spectrum disorder with anti-aquaporin-4 antibody were assessed retrospectively. Patient demographics, clinical characteristics at each attack, and type of treatment during inter-attack periods were assessed. The dependent variable was defined as the time from each attack to the next attack (inter-attack interval). An exponential accelerated failure time model with shared gamma frailty was adapted for statistical analysis. Results A multivariable analysis revealed that the time from each attack to the next attack in NMO increased independently by 1.31 times (95% confidence interval (CI), 1.02–1.67; p = 0.035) with each additional cumulative attack experienced, by 5.34 times (95% CI, 1.57–18.13; p = 0.007) with combined azathioprine treatment and continued oral prednisolone, and by 4.26 times (95% CI, 1.09–16.61; p = 0.037) with rituximab treatment. Conclusion The time to next attack in NMO can increase naturally in the later stages of the disease as the number of cumulative attacks increases. Nevertheless, both combined azathioprine treatment with continued oral prednisolone and rituximab treatment were also associated with a longer time to next attack, independently of the natural disease course of NMO.
Oscillation Control Algorithms for Resonant Sensors with Applications to Vibratory Gyroscopes
Sungsu Park,Chin-Woo Tan,Haedong Kim,Sung Kyung Hong
Sensors , 2009, DOI: 10.3390/s90805952
Abstract: We present two oscillation control algorithms for resonant sensors such as vibratory gyroscopes. One control algorithm tracks the resonant frequency of the resonator and the other algorithm tunes it to the specified resonant frequency by altering the resonator dynamics. Both algorithms maintain the specified amplitude of oscillations. The stability of each of the control systems is analyzed using the averaging method, and quantitative guidelines are given for selecting the control gains needed to achieve stability. The effects of displacement measurement noise on the accuracy of tracking and estimation of the resonant frequency are also analyzed. The proposed control algorithms are applied to two important problems in a vibratory gyroscope. The first is the leading-following resonator problem in the drive axis of MEMS dual-mass vibratory gyroscope where there is no mechanical linkage between the two proof-masses and the second is the on-line modal frequency matching problem in a general vibratory gyroscope. Simulation results demonstrate that the proposed control algorithms are effective. They ensure the proof-masses to oscillate in an anti-phase manner with the same resonant frequency and oscillation amplitude in a dual-mass gyroscope, and two modal frequencies to match in a general vibratory gyroscope.
Estimating Crown Variables of Individual Trees Using Airborne and Terrestrial Laser Scanners
Sung-Eun Jung,Doo-Ahn Kwak,Taejin Park,Woo-Kyun Lee,Seongjin Yoo
Remote Sensing , 2011, DOI: 10.3390/rs3112346
Abstract: In this study, individual tree height (TH), crown base height (CBH), crown area (CA) and crown volume (CV), which were considered as essential parameters for individual stem volume and biomass estimation, were estimated by both an airborne laser scanner (ALS) and a terrestrial laser scanner (TLS). These ALS- and TLS-derived tree parameters were compared because TLS has been introduced as an instrument to measure objects more precisely. ALS-estimated TH was extracted from the highest value within a crown boundary delineated with the crown height model (CHM). The ALS-derived CBH of individual trees was estimated by k-means clustering method using the ALS data within the boundary. The ALS-derived CA was calculated simply with the crown boundary, after which CV was computed automatically using the crown geometric volume (CGV). On the other hand, all TLS-derived parameters were detected manually and precisely except the TLS-derived CGV. As a result, the ALS-extracted TH, CA, and CGV values were underestimated whereas CBH was overestimated when compared with the TLS-derived parameters. The coefficients of determination (R2) from the regression analysis between the ALS and TLS estimations were approximately 0.94, 0.75, 0.69 and 0.58, and root mean square errors (RMSEs) were approximately 0.0184 m, 0.4929 m, 2.3216 m2 and 13.2087 m3 for TH, CBH, CA and CGV, respectively. Thereby, the error rate decreased to 0.0089, 0.0727 and 0.0875 for TH, CA and CGV via the combination of ALS and TLS?data.
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