311 results on '"Hyon Park"'
Search Results
102. Results From South Korea’s 2016 Report Card on Physical Activity for Children and Youth
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Hyon Park, Mi Seong Yu, Eun-Young Lee, Sang Hoon Suh, John C. Spence, Yoonkyung Song, Wook Song, Yeon Soo Kim, Han Joo Lee, Hyun Joo Kang, Justin Y. Jeon, Min Jae Kang, and Hyuk In Yang
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Research Report ,Gerontology ,Pediatrics ,medicine.medical_specialty ,Adolescent ,Physical activity ,Health Promotion ,Motor Activity ,03 medical and health sciences ,0302 clinical medicine ,Physical literacy ,Knowledge translation ,Republic of Korea ,medicine ,Humans ,Orthopedics and Sports Medicine ,030212 general & internal medicine ,Child ,Exercise ,Built environment ,Active play ,Government ,Health Policy ,030229 sport sciences ,Investment (macroeconomics) ,Play and Playthings ,Environment Design ,Sedentary Behavior ,Psychology ,Report card - Abstract
Background:South Korea’s 2016 Report Card on Physical Activity for Children and Youth is the first assessment of physical activity according to the indicators set by Active Healthy Kids Global Alliance.Methods:National surveys were used as preferred sources of data. This was then supported by peer-reviewed papers and government reports identified by a systematic search of the literature written in English or Korean. A Research Working Group then graded indicators based on the collected evidence.Results:Each indicator was graded as follows: Overall Physical Activity, D-; Organized Sport and Physical Activity Participation, C-; Active Transport, C+; Sedentary Behavior, F; School, D; Government and Investment, C; Active Play, Physical Literacy, Family and Peers, and Community and Built Environment were graded INC (incomplete) due to lack of available evidence.Conclusions:Though the final grades of key indicators for South Korean children and youth are not satisfactory, increasing interests and investments have been demonstrated at a national level. More evidence is required for comprehensive assessment on all indicators to better inform policy and practice. This should be accompanied by the use of consistent criteria to contribute to global efforts for active healthy kids.
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- 2016
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103. Acquired Palatal Fistula in Patients with Submucous and Incomplete Cleft Palate before Surgery
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Ie Hyon Park, Jihyeon Han, Suk Wha Kim, Jee Hyeok Chung, and Tae Hyun Choi
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medicine.medical_specialty ,Fistula ,business.industry ,lcsh:Surgery ,Dentistry ,Case Report ,030206 dentistry ,lcsh:RD1-811 ,030230 surgery ,medicine.disease ,Surgery ,03 medical and health sciences ,0302 clinical medicine ,Oral Fistula ,Cleft palate ,Submucous cleft palate ,medicine ,Palatal fistula ,In patient ,Oral fistula ,business - Abstract
It is uncommon for a palatal fistula to be detected in individuals who have not undergone surgery, and only sporadic cases have been reported. It is even more difficult to find cases of acquired palatal fistula in patients with submucous or incomplete cleft palate. Herein, we present 2 rare cases of this phenomenon. Case 1 was a patient with submucous cleft palate who acquired a palatal fistula after suffering from oral candidiasis at the age of 5 months. Case 2 was a patient with incomplete cleft palate who spontaneously, without trauma or infection, presented with a palatal fistula at the age of 9 months.
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- 2016
104. Bone Framework Graft through an Intraoral Approach in a Patient with Columellar Scar Contracture
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Myung-Good Kim, Baek-Kyu Kim, Chang Sik Pak, Ie Hyon Park, and Jae Hoon Jeong
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medicine.medical_specialty ,business.industry ,medicine.medical_treatment ,Intraoral approach ,lcsh:Surgery ,contracture ,General Medicine ,lcsh:RD1-811 ,030230 surgery ,Oral Surgical Procedures ,Rhinoplasty ,Surgery ,03 medical and health sciences ,0302 clinical medicine ,oral surgical procedures ,030220 oncology & carcinogenesis ,rhinoplasty ,medicine ,Scar contracture ,Contracture ,medicine.symptom ,business - Abstract
We present our experience with calvarial bone framework insertion through an intraoral approach for a patient who was at risk for columellar necrosis due to a previous open rhinoplasty. A 58-year-old woman exhibited severe columellar contracture, so that the columellar tissue was too fragile to be touched. We could not incise the columella and insert a new nasal implant through the bilateral rim incision. Moreover, the patient had septal cartilage perforation and collapse. The patient needed columellar support as well as nasal dorsum reconstruction. The authors decided to graft an autogenous L-strut bone framework through an intraoral approach. Two pieces of 5-cm × 1-cm sized split calvarial bone were harvested and trimmed to fit the width and length of the nasal dorsum and columella. The right-angle-shaped bone framework was made with an absorbable plate and screws. Through a gingivobuccal incision, the bone framework graft was inserted and the graft was fixed with absorbable screws. The patient did not experience complications such as skin necrosis or inflammation. A bone framework grafted through an intraoral approach can be a good choice for patients who have experienced scar contracture in the columella, septal cartilage perforation, and collapse.
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- 2016
105. Boundary detection with a road model for occupancy grids in the curvilinear coordinate system using a downward-looking lidar sensor
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Jin Han Jeong, Jahng-Hyon Park, and Je Seok Kim
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Boundary detection ,Curvilinear coordinates ,Occupancy grid mapping ,Laser scanning ,Occupancy ,business.industry ,Mechanical Engineering ,Coordinate system ,Aerospace Engineering ,Geography ,Lidar ,Computer vision ,Artificial intelligence ,business ,Remote sensing - Abstract
Many studies using a laser scanner have been conducted in order to study the environment of vehicles in real time. The method to find the driving area using a two-dimensional lidar sensor is divided into a forward-looking lidar sensor and a downward-looking lidar sensor based on the installation method. A downward-looking lidar sensor looks at the ground, enabling it to recognize kerbs and ditches which are lower than the installation position of the sensor. However, a downward-looking lidar sensor requires pre-processing to find the road boundary. The existing sensor models cannot generate an occupancy grid map without support, as the driving area recognized through a downward-looking lidar sensor forms a circular sector shape from the sensor installation position to the road boundary. This paper proposes a road sensor model that is capable of modelling an occupancy grid. We also propose a method to generate an occupancy grid map more suitable for autonomous vehicles by presenting the occupancy grid map in curvilinear space. The proposed method was validated by an experiment at Hanyang University campus and the quantitative results obtained from that experiment. We also compared this method with three conventional sensor model methods. The experimental results show that our method performs better than the conventional methods do in terms of both visual qualities and metric qualities.
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- 2016
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106. Social bricolage in the arts: Cheongna International City Culture Art Academy case
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Hyung Deok Shin and Ji Hyon Park
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Improvisation ,Persuasion ,Value creation ,business.industry ,media_common.quotation_subject ,Stakeholder ,Arts administration ,Public relations ,Development ,The arts ,Bricolage ,Service (economics) ,Political Science and International Relations ,Business, Management and Accounting (miscellaneous) ,Sociology ,business ,media_common - Abstract
Social bricolage literature suggests how social entrepreneurs can survive in managing socially beneficial firms under scare resources (Di Domenico et al., 2010). This study applies six principles of social bricolage suggested by Di Domenico et al. (2010) to understand how Cheongna International City Culture Arts Academy has developed its path in resource-scarce arts management environments in Korea. We found: 1) making do was possible owing to direct control of the founder with deep understanding in the arts; 2) refusal to be constrained by limitation was made by using legal advantages for students who participate in the orchestra to attract more members; 3) improvisation was possible by establishing various affiliated groups that fit needs of residents; 4) social value creation was made by providing educational service to local students; 5) stakeholder participation was made by making networks with local governmental institutes; 6) persuasion was made to secure practice rooms.
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- 2021
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107. Should Threshold Growth Be Considered a Major Feature in the Diagnosis of Hepatocellular Carcinoma Using LI-RADS?
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Yong Eun Chung, Jae Hyon Park, Myeong-Jin Kim, Mi-Suk Park, Nieun Seo, and Jin-Young Choi
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medicine.medical_specialty ,Carcinoma, Hepatocellular ,Contrast Media ,Sensitivity and Specificity ,Magnetic resonance imaging ,Liver neoplasms ,Diagnosis ,Humans ,Medicine ,Radiology, Nuclear Medicine and imaging ,neoplasms ,Retrospective Studies ,Liver imaging ,medicine.diagnostic_test ,Tumor size ,business.industry ,Retrospective cohort study ,medicine.disease ,digestive system diseases ,Liver ,Feature (computer vision) ,Hepatocellular carcinoma ,Gastrointestinal Imaging ,Original Article ,Radiology ,business ,Arterial phase - Abstract
Objective Based on the Liver Imaging Reporting and Data System version 2018 (LI-RADS, v2018), this study aimed to analyze LR-5 diagnostic performance for hepatocellular carcinoma (HCC) when threshold growth as a major feature is replaced by a more HCC-specific ancillary feature, as well as the frequency of threshold growth in HCC and non-HCC malignancies and its association with tumor size. Materials and Methods This retrospective study included treatment-naive patients who underwent gadoxetate disodium-enhanced MRIs for focal hepatic lesions and surgery between January 2009 and December 2016. The frequency of major and ancillary features was evaluated for HCC and non-HCC malignancies, and the LR-category was assessed. Ancillary features that were significantly more prevalent in HCC were then used to either replace threshold growth or were added as additional major features, and the diagnostic performance of the readjusted LR category was compared to the LI-RADS v2018. Results A total of 1013 observations were analyzed. Unlike arterial phase hyperenhancement, washout, or enhancing capsule which were more prevalent in HCCs than in non-HCC malignancies (521/616 vs. 18/58, 489/616 vs. 19/58, and 181/616 vs. 5/58, respectively; p < 0.001), threshold growth was more prevalent in non-HCC malignancies than in HCCs (11/23 vs. 17/119; p < 0.001). The mean size of non-HCC malignancies showing threshold growth was significantly smaller than that of non-HCC malignancies without threshold growth (22.2 mm vs. 42.9 mm, p = 0.040). Similar results were found for HCCs; however, the difference was not significant (26.8 mm vs. 33.1 mm, p = 0.184). Additionally, Fat-in-nodule was more frequent in HCCs than in non-HCC malignancies (99/616 vs. 2/58, p = 0.010). When threshold growth and fat-in-nodule were considered as ancillary and major features, respectively, LR-5 sensitivity (73.2% vs. 73.9%, p = 0.289) and specificity (98.2% vs. 98.5%, p > 0.999) were comparable to the LI-RADS v2018. Conclusion Threshold growth is not a significant diagnostic indicator of HCC and is more common in non-HCC malignancies. The diagnostic performance of LR-5 was comparable when threshold growth was recategorized as an ancillary feature and replaced by a more HCC-specific ancillary feature.
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- 2021
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108. Should Threshold Growth Be Considered a Major Feature in the Diagnosis of Hepatocellular Carcinoma Using LI-RADS?
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Jae Hyon Park, Yong Eun Chung, Nieun Seo, Jin-Young Choi, Mi-Suk Park, and Myeong-Jin Kim
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- 2021
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109. Bayesian statistical methods in genetic association studies: Empirical examination of statistically non-significant Genome Wide Association Study (GWAS) meta-analyses in cancers: A systematic review
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Jae Hyon Park, Hans van Vliet, Jae Il Shin, Dong Il Geum, and Michael Eisenhut
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0301 basic medicine ,Bayesian probability ,Single-nucleotide polymorphism ,Genome-wide association study ,Computational biology ,Biology ,Polymorphism, Single Nucleotide ,03 medical and health sciences ,0302 clinical medicine ,Neoplasms ,Genetics ,Odds Ratio ,Humans ,Genetic Predisposition to Disease ,p-value ,Allele frequency ,Alleles ,Genetic association ,Bayes Theorem ,General Medicine ,Odds ratio ,Confidence interval ,Neoplasm Proteins ,030104 developmental biology ,030220 oncology & carcinogenesis ,Genome-Wide Association Study - Abstract
A Bayesian statistical method was developed to assess the noteworthiness of a single nucleotide polymorphism (SNP)-phenotype association that shows statistical significance in various observational studies, but it has seldom been applied to GWAS meta-analyses in cancers. Data (i.e. allelic frequency, odds ratio, 95% confidence interval, etc.) on various SNP-cancer associations were extracted from meta-analysis of GWAS and the National Human Genome Research Institute (NHGRI) Catalog of Published GWAS and were used to compute the false positive report probability (FPRP) and Bayesian false discovery probability (BFDP) to evaluate the noteworthiness of SNP-cancer associations. Independent paired t-tests showed a direct relationship between SNP-cancer P-values and both FPRP and BFDP estimates. However, a discrepancy in the number of noteworthy associations between P-value comparison and either FPRP or BFDP was found using data extracted from meta-analyses of GWAS and the GWAS Catalog. Most P-values of associations with nonsignificant P-values but with noteworthy FPRP and BFDP estimates were within the range of 10−6 to 5 × 10−8. A poorly selected genome-wide significance threshold and inclusion of a nonsignificant SNP-phenotype association into the noteworthy test can, with either noteworthy FPRP or BFDP computation, give a false impression of noteworthiness for a nonsignificant association.
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- 2018
110. Control Allocation of Rear Wheel Steering and Electronic Stability Control with Actuator Failure
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Sungwook Lee, Wanggi Hong, Yookhyun Yoon, and Jahng-Hyon Park
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Chassis ,Computer science ,020302 automobile design & engineering ,Fault tolerance ,02 engineering and technology ,CarSim ,Optimal control ,020303 mechanical engineering & transports ,0203 mechanical engineering ,Electronic stability control ,Control theory ,Control system ,Brake ,Actuator - Abstract
This paper has presented optimal coordination of Rear Wheel Steering and Electronic Stability Control. The algorithm consists of three parts. First, state estimators for tire force, cornering stiffness and side slip angle have been designed. Second, desired vehicle motion has been generated considering driving situation and driver’s intention. Third, optimal coordinator has distributed the control task to the individual chassis control using analytical method with Karush-Kuhn-Tucker. The purpose of this study can be divided into two categories. One is optimal control of Rear Wheel Steering and Electronic Stability Control. Therefore, new cost functions have been defmed. The other is fault tolerant control during actuator fault or brake circuit failure. The performance of the proposed control system has been validated through closed-loop simulations with MATLABlSimulink and Carsim. The simulation results show that proposed system does not only distribute the control input to each control system but also ensure vehicle safety under actuator failure.
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- 2018
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111. Results from South Korea's 2018 Report Card on physical activity for children and youth
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Sang Hoon Suh, J. Lim, Hyon Park, SoJung Lee, Hyun Joo Kang, Yu Sun Jin, Deok Hwan Lee, Mi Seong Yu, Jung Woo Oh, Bumjo Oh, Sang Hwa Lee, Soo Jung Park, Youngwon Kim, Bong Kil Song, Yeon Soo Kim, Han Joo Lee, Chung Gun Lee, Yewon Yu, Se Jung Park, Sungchul Im, Wook Song, Yoonkyung Song, Justin Y. Jeon, and Eun-Young Lee
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Government ,National Health and Nutrition Examination Survey ,Descriptive statistics ,business.industry ,media_common.quotation_subject ,Physical fitness ,Public Health, Environmental and Occupational Health ,030209 endocrinology & metabolism ,Physical Therapy, Sports Therapy and Rehabilitation ,030229 sport sciences ,03 medical and health sciences ,0302 clinical medicine ,Promotion (rank) ,Health promotion ,Environmental health ,business ,Psychology ,Report card ,Health policy ,media_common - Abstract
Background/Objective South Korea's 2018 Report Card on Physical Activity for Children and Youth is the second comprehensive evaluation of physical activity and the sources of influence based on the 10 core indicators provided by the Active Healthy Kids Global Alliance. It will serve as an advocacy tool to promote physical activity among children and youth. Methods Three national surveillance data (i.e., 2017 Korea Youth Risk Behavior Web-based Survey, 2016 Korea National Health and Nutrition Examination Survey, 2016 Physical Activity Promotion System) were used as main sources to evaluate the indicators. Descriptive statistics were performed to obtain prevalence estimates of physical activity-related indicators. In addition, expert opinions as well as the most recently available published or unpublished relevant sources were synthesized. Results South Korea's 2018 Report Card, compared to the 2016 Report Card, showed favourable changes in the Active Transportation (B+), Organized Sports Participation (C), Sedentary Behaviours (D), and School (D+) indicators, while unfavourable changes were shown in Overall Physical Activity (F) and Government (D). Physical Fitness was graded as D+. In parallel with the 2016 Report Card, Active Play, Family and Peers, and Community and Environment remain ungraded due to insufficient data. Conclusions Successes as well as gaps and research needs were identified in the 2018 Report Card. Though some indicators have shown improvement, most children and youth continue to be insufficiently physically active with overall poor grades (Average of D+). To achieve substantial improvement in all grades in future Report Cards, more institutional and governmental support and investment is needed to promote physical activity. Furthermore, effort should be made to generate data pertaining to the indicators that were ungraded.
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- 2018
112. A geometric approach for forward kinematics analysis of a 3-SPS/S redundant motion manipulator with an extra sensor using conformal geometric algebra
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Jahng-Hyon Park, Je Seok Kim, and Yong Hoon Jeong
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0209 industrial biotechnology ,Iterative and incremental development ,Forward kinematics ,Mechanical Engineering ,Conformal geometric algebra ,Motion (geometry) ,Geometry ,02 engineering and technology ,Kinematics ,Condensed Matter Physics ,Base (topology) ,Topology ,Mechanism (engineering) ,020303 mechanical engineering & transports ,020901 industrial engineering & automation ,0203 mechanical engineering ,Mechanics of Materials ,Actuator ,ComputingMethodologies_COMPUTERGRAPHICS ,Mathematics - Abstract
This paper proposes a geometric approach for forward kinematics analysis of a 3-SPS/S redundant motion mechanism using conformal geometric algebra (CGA). The forward kinematics of a parallel kinematic mechanism is generally very complicated and difficult to analyze. The proposed geometric method is useful because it provides simple, fast, and complete solutions to the problem and helps determine the relationship between the joints and end-effector without an iterative process. Thus, we introduce a geometric approach using CGA in an intuitive, stepwise fashion. We also use an extra sensor to provide more positional information, thereby allowing a unique solution to be selected geometrically from among the multiple solutions found using the geometric approach. In the mechanism considered herein, three identical legs linked by prismatic actuators are attached to a moving platform and to the base by two passive spherical joints. A passive leg is present at the center of the mechanism; it connects the center of the base to the platform, constraining the platform’s movement. The added components constrain the movement of the platform, making it possible to analyze the mechanism using a geometric approach. Herein we present performance comparisons that validate use of the proposed approach in real-time applications and demonstrate its low computational load.
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- 2016
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113. Kinematics Optimization of a 3-SPS Parallel Redundant Motion Mechanism Using Conformal Geometric Algebra
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Jin Han Jeong, Jahng-Hyon Park, and Jeseok Kim
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Computer Science::Robotics ,Mathematical optimization ,Infinite number ,Rigidity (electromagnetism) ,Inverse kinematics ,Control theory ,Parallel manipulator ,Redundancy (engineering) ,Conformal geometric algebra ,Inverse ,General Medicine ,Kinematics ,Mathematics - Abstract
In this paper, an actuation mechanism for high-speed aiming of a target is proposed. The mechanism is a 3DOF-SPS (spherical-prismatic-spherical) parallel manipulator and can be used for a missile defense system with a fast reaction time. This type of parallel mechanism has high rigidity against external disturbances and accordingly high stiffness and precision. The target aiming requires 2 degrees of freedom and this 3 DOF mechanism has one redundancy. For fast manipulation of the proposed mechanism, the redundancy can be exploited and an optimal solution can be found out of the infinite number of inverse kinematic solutions. For finding a near time-optimal solution, a cost function is formulated considering displacement of each parallel link and an optimization technique is used for solution of the inverse kinematic problem.
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- 2015
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114. Inverse kinematics and geometric singularity analysis of a 3-SPS/S redundant motion mechanism using conformal geometric algebra
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Jin Han Jeong, Je Seok Kim, and Jahng-Hyon Park
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Correctness ,Inverse kinematics ,Mechanical Engineering ,Conformal geometric algebra ,Motion (geometry) ,Bioengineering ,Topology ,Computer Science Applications ,Orientation (vector space) ,Mechanics of Materials ,Redundancy (engineering) ,Robot ,Configuration space ,ComputingMethodologies_COMPUTERGRAPHICS ,Mathematics - Abstract
We propose a 3-SPS/S redundant motion mechanism with kinematic redundancy in this paper. The proposed mechanism with redundancy enables redundant motion as it works like pan/tilt systems to reduce the unnecessary degree of freedom for the yaw and pitch motions in the configuration space. By reducing one degree of freedom, this robot has self-motion that causes the inverse kinematics to have infinite solutions, so that the proposed research performs an optimization process for obtaining the optimal solution using geometric approaches. This optimal solution provides the fastest response among the infinite solutions by minimizing each link movement to the target orientation. In addition, we perform a geometric singularity analysis due to limited link length and avoidance using conformal geometric algebra for the feasibility and correctness of the inverse kinematics.
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- 2015
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115. Differential Effects of Strong Corporate Governance on Both Professional and Voluntary Corporate Social Responsibility Activities of the Firm
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Ji Hyon Park, Hyung-Deok Shin, and Namryoung Lee
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business.industry ,Turnover ,Corporate governance ,Long period ,Corporate social responsibility ,Organizational structure ,Accounting ,Public relations ,business ,General Economics, Econometrics and Finance ,Social responsibility ,Differential effects ,Finance - Abstract
Corporate social responsibility (CSR) has been of interest in the past decade, but prior studies have not investigated the relationship between strong corporate governance and types of CSR activities. This study introduces the concept of professional CSR activities (which means CSR activities pursued in a formal organizational structure over a long period) and voluntary CSR activities (which means CSR activities pursued tentatively and individually) and how strong corporate governance has differential effects on the two types of CSR activities. Our empirical results show that the stronger the corporate governance is, the more professional CSR activities are encouraged.
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- 2015
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116. Advanced Lane Change Assist System for Automatic Vehicle Control in Merging Sections : An algorithm for Optimal Lane Change Start Point Positioning
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Jhang-Kyung Young, Sung-Hyun You, Janhg-Hyon Park, Jinsoo Kim, and Jinhan Jeong
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Transport engineering ,Government ,Engineering ,Engineering management ,Work (electrical) ,business.industry ,Foundation (engineering) ,business - Abstract
This work was supported by the National Research Foundation of Korea grant funded by the Korea government (MEST) (NRF-2014-038479,NRF-2013-034204)
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- 2015
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117. Body mass index and 20 specific cancers: re-analyses of dose-response meta-analyses of observational studies
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H. J. van der Vliet, Jae Hyon Park, Eun Kyoung Choi, Hyunbong Park, Michael Eisenhut, Keum Hwa Lee, Jae Il Shin, Gaeun Kim, CCA - Cancer Treatment and quality of life, and Medical oncology
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Oncology ,Adult ,Male ,medicine.medical_specialty ,Body Mass Index ,03 medical and health sciences ,Prostate cancer ,0302 clinical medicine ,Meta-Analysis as Topic ,Renal cell carcinoma ,Prostate ,Internal medicine ,Neoplasms ,medicine ,Humans ,030212 general & internal medicine ,Thyroid cancer ,Multiple myeloma ,business.industry ,Cancer ,Hematology ,medicine.disease ,Leukemia ,Observational Studies as Topic ,medicine.anatomical_structure ,030220 oncology & carcinogenesis ,Female ,business ,Body mass index - Abstract
Background: Objectives were to provide an overview and understand the strength of evidence and extent of potential biases and validity of claimed associations between body mass index (BMI) and risk of developing cancer.Methods: We carried out an umbrella review and comprehensively re-analyzed the data of dose-response meta-analyses on associations between BMI and risk of 20 specific cancers (bladder, brain, breast, colonic, rectal, endometrial, gallbladder, gastric, leukemia, liver, lung, melanoma, multiple myeloma, non-Hodgkins lymphoma, esophagus, ovarian, pancreatic, prostate, renal, thyroid) by adding big data or missed individual studies. Convincing evidence for an association was defined as a strong statistical significance in fixed-effects and random-effects meta-analyses at P Results: Convincing evidence for an association with BMI was detectable for six cancers (leukemia, multiple myeloma, pancreatic, endometrial, rectal, and renal cell carcinoma). Suggestive evidence was detectable for malignant melanoma, non-Hodgkins lymphoma, and esophageal adenocarcinoma. Weak evidence was detectable for brain and central nervous system tumors, breast, colon, gall bladder, lung, liver, ovarian, and thyroid cancer. No evidence was detectable for bladder, gastric, and prostate cancer.Conclusions: The association of increased BMI and cancer is heterogeneous across cancer types. Leukemia, multiple myeloma, pancreatic, endometrial, rectal, and renal cell carcinoma are convincingly associated with an increased BMI by dose-response meta-analyses.
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- 2018
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118. Geometric Singularity Avoidance of a 3-SPS/S Parallel Mechanism with Redundancy using Conformal Geometric Algebra
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Je Seok Kim, Jin Han Jeong, and Jahng-Hyon Park
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Singularity ,Inverse kinematics ,Mechanical Engineering ,Universal geometric algebra ,Conformal geometric algebra ,Redundancy (engineering) ,Boundary (topology) ,Gravitational singularity ,Configuration space ,Safety, Risk, Reliability and Quality ,Topology ,Industrial and Manufacturing Engineering ,Mathematics - Abstract
A parallel mechanism with redundancy can be regarded as a means for not only maximizing the benefits of parallel mechanisms but also overcoming their drawbacks. We proposed a novel parallel mechanism by eliminating an unnecessary degree of freedom of the configuration space. Because of redundancy, however, the solution for the inverse kinematics of the developed parallel mechanism is infinite. Therefore, we defined a cost function that can minimize the movement time to the target orientation and found the solution for the inverse kinematics by using a numerical method. In addition, we proposed a method for determining the boundary of the geometric singularity in order to avoid singularities.
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- 2015
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119. Six week swimming followed by acute uptakes of ginsenoside Rg1 may affect aerobic capacity of SD rats
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Hyon Park and Saebom Haam
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Muscle tissue ,medicine.medical_specialty ,biology ,Ginsenoside Rg1 ,business.industry ,citrate synthase expression ,Affect (psychology) ,Placebo ,aerobic capacity ,medicine.anatomical_structure ,Endocrinology ,Internal medicine ,Physical therapy ,medicine ,biology.protein ,Citrate synthase ,Aerobic exercise ,Original Article ,swimming ,business ,Erg ,Aerobic capacity - Abstract
[Purpose] The purpose of this study is to examine the effects of six-weeks of endurance swim training and short-term intake of Rg1 on the expression of related proteins as well as improvement of aerobic exercise capacity in 8-week-old male SD rats. [Methods] The groups were divided into placebo (NP, n=6), Rg1 (NRG, n=6), exercise+placebo (EP, n=7), and exercise+Rg1 (ERG, n=7). On completion of the 6-week swimming exercise, Rg1-intake groups were treated with acute uptakes (3 times within 24hrs) of Rg1. After the treatment, all groups were subjected to a swim to exhaustion test, and then the mass of muscle tissue, mRNA expression level and activity of citrate synthase (CS) were analyzed on plantaris. [Results] There were no differences in the effect of 6-week swimming exercise and short-term intake of Rg1 on body weight and muscle mass between groups. Although the CS mRNA expression was elevated in the exercise group and combined treatment group, there was no significant difference in CS activity. Acute uptakes of Rg1 did not affect swimming time to exhaustion, but it was increased by 235% and 314% by the 6-weeks of exercise and combined treatment of exercise and Rg1, respectively, which suggests that the combined treatment increased the effect on the capacity of aerobic exercise. [Conclusion] Based on these results, it was confirmed that even a short-term treatment of Rg1 can give an additive effect for improvement of exercise function, and additional studies are needed for the mechanisms and modes of its working.
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- 2015
120. Posterior nutcracker syndrome - a systematic review
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Keum Hwa Lee, Michael Eisenhut, Jae Il Shin, Andreas Kronbichler, Seul Mi Lee, Jae Hyon Park, and Gi Hoon Lee
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Renal Nutcracker Syndrome ,Aorta ,Conservative management ,business.industry ,030232 urology & nephrology ,Left renal vein ,Anatomy ,Constriction, Pathologic ,030204 cardiovascular system & hematology ,medicine.disease ,Renal Veins ,03 medical and health sciences ,Entrapment ,Nutcracker syndrome ,0302 clinical medicine ,medicine.anatomical_structure ,medicine.artery ,medicine ,Humans ,Cardiology and Cardiovascular Medicine ,business ,Vertebral column ,Hematuria - Abstract
Abstract. Posterior nutcracker syndrome (PNCS) is the entrapment of the left renal vein between the aorta and the vertebral column. Although uncommon, it is still an important diagnosis due to the high morbidity associated with the risk of secondary anaemia from haematuria, from long-term left renal vein hypertension, vascular thrombosis, and even blood clots in the urinary system. A literature search of PubMed and EMBASE databases was performed and 27 publications containing 27 cases were included for the final analysis. The following frequency of clinical signs and symptoms was noted: twenty-five patients had haematuria, 13 patients had flank pain, and two had hypertension. Overall, male-female distribution was balanced and there were more adult than paediatric (age < 18 years) patients. All symptoms of patients with conservative treatment were either well-controlled or under spontaneous resolution. Conservative management instead of surgical treatment should be preferred in most cases. Taken together, despite the low incidence of PNCS, its recognition and management are highly important. This systematic study explores the evidence base for conservative and medical options.
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- 2017
121. The Effects of Neurofeedback Training on Concentration in Children with Attention Deficit/Hyperactivity Disorder
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Ji-Hyuk Park, Min Ye Jung, Eun Young Yoo, Jae Shin Lee, Su Kyoung Kim, and Soo Hyon Park
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medicine.medical_specialty ,Teacher rating ,medicine.diagnostic_test ,Biomedical Engineering ,Relative power ,Bioengineering ,Electroencephalography ,Audiology ,medicine.disease ,Auditory Continuous Performance Test ,Correlation ,Artificial Intelligence ,medicine ,Attention deficit hyperactivity disorder ,Statistical analysis ,Neurofeedback ,Psychiatry ,Psychology ,Biotechnology - Abstract
This study investigated the effects of neurofeedback training on concentration in children with attention deficit/ hyperactivity disorder (ADHD). A single-subject ABA' experimental design was used to determine the effects of neurofeedback training. The participants of the study were three boys with ADHD. In the intervention phase after the baseline assessment, participant 1 and 3 trained neurofeedback for twelve sessions, and participant 2 trained ten times. The EEG was recorded during each session and was analyzed for relative power spectrum by beta/theta ratio. The concentration behaviors were measured on a 10-second interval scale during 15 minutes. The concentration was assessed using Auditory Continuous Performance Test (ACPT), and the ADHD symptoms were assessed by the Conners Teacher Rating Scale-Revised (CTRS-R) in pre and posttest. The data were visually analyzed using graphs and descriptive statistical analysis. The results of the study suggest that, after the neurofeedback training sessions, the participants showed a significant increase in their concentration behaviors. The scores of ACPT and CRTS-R were improved as well. However, no significant EEG change was observed, and no correlation of EEG with concentration behaviors was established.
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- 2014
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122. Multi-Objective Genetic Algorithm based on Multi-Robot Positions for Scheduling Problems
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Jin Han Jeong, Jahng-Hyon Park, Jong Hoon Choi, Jung Min Kim, and Je Seok Kim
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Mathematical optimization ,Job shop scheduling ,Computer science ,Mechanical Engineering ,Algorithmics ,Population-based incremental learning ,Algorithm design ,Dynamic priority scheduling ,Safety, Risk, Reliability and Quality ,Difference-map algorithm ,Industrial and Manufacturing Engineering ,Fair-share scheduling ,FSA-Red Algorithm - Abstract
This paper presents a scheduling problem for a high-density robotic workcell using multi-objective genetic algorithm. We propose a new algorithm based on NSGA-II(Non-dominated Sorting Algorithm-II) which is the most popular algorithm to solve multi-objective optimization problems. To solve the problem efficiently, the proposed algorithm divides the problem into two processes: clustering and scheduling. In clustering process, we focus on multi-robot positions because they are fixed in manufacturing system and have a great effect on task distribution. We test the algorithm by changing multi-robot positions and compare it to previous work. Test results shows that the proposed algorithm is effective under various conditions.
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- 2014
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123. Effects of vitamin D supplementation and circuit training on indices of obesity and insulin resistance in T2D and vitamin D deficient elderly women
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Hyoung-Jun Kim, Hyon Park, Man-Gyoon Lee, and Chang-Kyun Kang
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medicine.medical_specialty ,Original Paper ,business.industry ,Diabetes ,Abdominal fat ,Repeated measures design ,Blood lipids ,Insulin resistance ,medicine.disease ,Obesity ,Circuit training ,Endocrinology ,Elderly ,Internal medicine ,Diabetes mellitus ,medicine ,Vitamin D and neurology ,Lean body mass ,Analysis of variance ,Vitamin D ,business - Abstract
[Purpose] The purpose of this study was to investigate the effects of vitamin D supplementation and circuit training on body composition, abdominal fat, blood lipids, and insulin resistance in T2D and vitamin D deficient elderly women. [Methods] Fifty-two elderly women were randomly assigned to either the vitamin D supplementation with circuit training group (D+T: n = 15), the circuit training group (T: n = 13), the vitamin D supplementation group (D: n = 11), or the control group (CON: n = 13). The subjects in D took vitamin D supplements at 1,200 IU per day for 12 weeks; the subjects in T exercised 3 to 4 times per week, 25 to 40 minutes per session for 12 weeks; and the subjects in D+T participated in both treatments. Subjects in CON were asked to maintain normal daily life pattern for the duration of the study. Body composition, abdominal fat, blood lipids, and surrogate indices for insulin resistance were measured at pre- and post-test and the data were compared among the four groups and between two tests by utilizing two-way ANOVA with repeated measures. The main results of the present study were as follows: [Results] 1) Body weight, fat mass, percent body fat, and BMI decreased significantly in T, whereas there were no significant changes in the variables in D and CON. Lean body mass showed no significant changes in all groups. 2) TFA and SFA decreased significantly in T, whereas there were no significant changes in the variables in D and CON. The other abdominal fat related variables showed no significant changes in all groups. 3) TC, TG, HDL-C, and LDL-C showed improvements in T, whereas there were no significant changes in the variables in D and CON. 4) Fasting glucose, fasting insulin, and HOMA-IR tended to be lower in D+T. [Conclusion] It was concluded that the 12 weeks of vitamin D supplementation and circuit training would have positive effects on abdominal fat and blood lipid profiles in T2D and vitamin D deficient elderly women. Vitamin D supplementation was especially effective when it was complemented with exercise training.
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- 2014
124. The Effects of 12-Weeks of Vitamin D Supplementation and Circuit Training on Skeletal Muscle Mass in Elderly Women with Type-2 Diabetes Mellitus and Vitamin D Deficiency
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Hyung-Jun Kim, Chang-Kyun Kang, Gina Ok, Hyon Park, and Man-Gyoon Lee
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Circuit training ,medicine.medical_specialty ,Vitamin d supplementation ,business.industry ,sports ,Type 2 Diabetes Mellitus ,Skeletal muscle mass ,medicine.disease ,vitamin D deficiency ,Endocrinology ,Internal medicine ,medicine ,sports.sport ,business - Published
- 2014
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125. Verification of efficacy as an ergogenic aid and safety in doping of sibjeondaebo-tang
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Geun Hoon Choi, Chang Kyun Kang, Hyon Park, Hyun Jin Yoo, and Man Gyoon Lee
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Herb medicine ,medicine.medical_specialty ,Original Paper ,biology ,Taekwondo ,Athletes ,business.industry ,biology.organism_classification ,ergogenic aid ,Test (assessment) ,Sibjeondaebo-Tang ,Exercise performance ,Blood lactate ,Step test ,Physical therapy ,Doping ,Medicine ,business ,human activities - Abstract
Hyun Jin Yoo, Geun Hoon Choi, Man Gyoon Lee, Chang Kyun Kang and Hyon Park. Verification of efficacy as an ergogenicaid and safety in doping of sibjeondaebo-tang. JENB., Vol. 18, No. 2, pp.189-195, 2014 [Purpose]Various kinds of food substances from all over the world have been proposed to use as ergogenic aids for the additional improvement of exercise performance especially in athletes. Herb medicine which usually being applied for the cure of disease is used as a performance booster in several far eastern countries including Korea. Many scientists and coaches have asked very objective verifications on the realityof herb medicines practically used but never been scientifically elucidated well enough. In addition to the possibility as an ergogenicaid, the safety in doping is the critical factor to be examined thoroughly. In this study, Sibjeondaebo-Tang, a leading popular prescribed herb medicine in Korea, was examined. [Methods]After the intake of Sibjeondaebo-Tang, its effects on V˙O2max, recovery from fatigue, and doping safety through the official process as WADA suggested. Six volunteered male Taekwondo Pumsae players were subjected in a repeatedly examined protocol. [Results]First of all, every subjects showed ‘negative’ in doping test, and the treatment did not show any significant improvement on VO2max even though there was a significant decrease in blood lactate level on a step test. [Conclusion]In conclusion, Sibjeondaebo-Tang may have some limited effects as a fatigue delayer and the use of it showed safe to doping test with the strict limitation as the way in this study. So we should abstain from the over-interpreted application of the results so far. [Keywords]ergogenic aid, Doping, Taekwondo, Sibjeondaebo-Tang
- Published
- 2014
126. Weighted‐graph‐based supervoxel segmentation of 3D point clouds in complex urban environment
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Je Seok Kim and Jahng Hyon Park
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Computer science ,business.industry ,Segmentation-based object categorization ,Point cloud ,Scale-space segmentation ,Image segmentation ,computer.software_genre ,Graph ,Computer graphics ,Shortest path problem ,Graph (abstract data type) ,Segmentation ,Computer vision ,Artificial intelligence ,Data mining ,Electrical and Electronic Engineering ,business ,computer - Abstract
A new method for supervoxel segmentation based on a weighted graph in complex urban environment is proposed. The proposed algorithm is designed to minimise the cost of the shortest path in the weighted graph with consideration of characteristics of the sensor for complex urban environment. We collected point clouds in a complex urban environment to evaluate the proposed method. The performance of the proposed algorithm was evaluated using boundary recall and under-segmentation errors.
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- 2015
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127. The Effect of Dietary Creatine and Leucine Supplementation on Protein Synthesis and Functional Properties of Skeletal Muscle During 8 Weeks of Resistance Exercise
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Soeun Jeon, Gina Ok, and Hyon Park
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medicine.medical_specialty ,business.industry ,Resistance training ,Skeletal muscle ,Creatine ,chemistry.chemical_compound ,Endocrinology ,medicine.anatomical_structure ,chemistry ,Internal medicine ,Physical therapy ,medicine ,Protein biosynthesis ,Leucine ,business - Published
- 2014
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128. Expression of stress-induced phosphoprotein1 (STIP1) is associated with tumor progression and poor prognosis in epithelial ovarian cancer
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Hanbyoul Cho, Sunghoon Kim, Ha-Yeon Shin, Eun Joo Chung, Haruhisa Kitano, Jae Hyon Park, Lucienne Park, Joon-Yong Chung, Stephen M. Hewitt, and Jae-Hoon Kim
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Oncology ,Cancer Research ,medicine.medical_specialty ,Poor prognosis ,business.industry ,Tumor progression ,Internal medicine ,Stress induced ,Genetics ,medicine ,Epithelial ovarian cancer ,business - Published
- 2014
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129. Inflamed Symptomatic Sellar Arachnoid Cyst: Case Report
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Ho-Shin Gwak, Kwang Hyon Park, Sang Hyun Lee, and Eun Kyung Hong
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Transsphenoidal surgery ,Pituitary stalk ,Inflammation ,Pathology ,medicine.medical_specialty ,business.industry ,medicine.medical_treatment ,Case Report ,Symptomatic ,medicine.disease ,Arachnoid cyst ,Polyuria ,Diabetes insipidus ,medicine ,Sellar ,General Earth and Planetary Sciences ,Vaginal bleeding ,Cyst ,medicine.symptom ,business ,Infection ,Polydipsia ,General Environmental Science - Abstract
Sellar arachnoid cysts are rare; an infected arachnoid cyst is extremely rare as only one case has been reported to date in the literature. Here, we report a patient with an infected or inflamed sellar arachnoid cyst that was successfully treated with transsphenoidal surgery (TSA). A 53-year-old female with a history of chronic sinusitis developed a headache 5 months ago, and one month before admission polyuria, polydipsia, and abnormal vaginal bleeding occurred. The magnetic resonance imaging (MRI) showed a sellar cystic mass with a thickened pituitary stalk. Preoperative hormonal study revealed normal pituitary hormone levels except for a moderate elevation of prolactin. She was diagnosed with diabetes insipidus of the central nervous system origin based on a water-deprivation test. TSA was performed under an impression of symptomatic Rathke's cleft cyst according to the MRI findings. Intraoperative findings showed confirmation of turbid intracystic contents, but micro-organisms were unidentified on microbial culture. Pathology of the cyst wall revealed inflamed meningoepithelial lining cells compatible with an arachnoid cyst.
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- 2013
130. Delta neutrophil index (DNI) as a novel diagnostic and prognostic marker of infection: a systematic review and meta-analysis
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Hyeong Ju Byeon, Jae Il Shin, Keum Hwa Lee, Michael Eisenhut, Jae Hyon Park, Jong Wook Lee, and Andreas Kronbichler
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Oncology ,Prognostic factor ,medicine.medical_specialty ,Neutrophils ,Immunology ,Logistic regression ,Infections ,Sensitivity and Specificity ,03 medical and health sciences ,0302 clinical medicine ,Internal medicine ,medicine ,Animals ,Humans ,030212 general & internal medicine ,Pharmacology ,Contingency table ,Receiver operating characteristic ,business.industry ,030208 emergency & critical care medicine ,Prognosis ,Predictive factor ,Clinical Practice ,Meta-analysis ,business ,Area under the roc curve ,Biomarkers - Abstract
Delta neutrophil index (DNI) representing the number of immature granulocytes is an emerging marker used in diagnosis of infections and prediction of mortality in infected patients. The present study evaluated the diagnostic accuracy of DNI as a predictive and prognostic factor in infected patients. We performed a PubMed search on January 1st, 2017 and identified studies that evaluated DNI as either a predictive or prognostic factor in infected patients. Studies with appropriate information to construct 2 × 2 contingency tables were extracted. We calculated pooled sensitivity and specificity. Meta-analysis of the multivariate logistic regression data set was performed to assess whether DNI functions as an independent factor. Overall, 12 articles fulfilled the inclusion criteria and a total of 499 cases and 9549 controls were examined. As a predictive factor of infection, DNI’s pooled sensitivity was 0.67 (95% CI 0.62–0.71, I 2 = 86.0%) and pooled specificity was 0.94 (95% CI 0.94–0.95, I 2 = 92.8%). Area under the receiver operating characteristics (ROC) curve was 0.89. As a prognostic factor for death in infected patients, DNI’s pooled sensitivity was 0.70 (95% CI 0.56–0.81, I 2 = 0.0%) and pooled specificity was 0.78 (95% CI 0.73–0.83, I 2 = 26.6%). Area under the ROC curve was 0.84. Meta-analysis of the multivariate logistic regression data set showed insignificant results. DNI is a potentially useful diagnostic tool and predicts mortality among infected patients and should be more widely used in the clinical practice.
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- 2017
131. The value of delta neutrophil index in young infants with febrile urinary tract infection
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Se Jin Park, Jae Hyon Park, Jae Il Shin, Michael Eisenhut, Seong Heon Kim, Andreas Kronbichler, Ji Hong Kim, Jung Won Lee, Keum Hwa Lee, and Jong Wook Lee
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Male ,medicine.medical_specialty ,Fever ,Neutrophils ,Urinary system ,Blood Sedimentation ,Gastroenterology ,Vesicoureteral reflux ,Article ,03 medical and health sciences ,0302 clinical medicine ,030225 pediatrics ,White blood cell ,Internal medicine ,Reflex ,medicine ,Humans ,030212 general & internal medicine ,Multidisciplinary ,biology ,Receiver operating characteristic ,medicine.diagnostic_test ,Immature Granulocyte ,business.industry ,C-reactive protein ,Infant ,medicine.disease ,medicine.anatomical_structure ,C-Reactive Protein ,Logistic Models ,ROC Curve ,Dimercaptosuccinic acid ,Erythrocyte sedimentation rate ,Area Under Curve ,Immunology ,Urinary Tract Infections ,biology.protein ,Female ,business ,Succimer ,medicine.drug - Abstract
Delta neutrophil index (DNI) is the fraction of circulating immature granulocytes, which reflects severe bacterial infections and septic condition but has not been studied in urinary tract infection (UTI). Here, we evaluated the value of DNI in predicting acute pyelonephritis (APN) or vesicoureteral reflux (VUR) using the data of 288 patients. Conventional inflammatory markers (white blood cell [WBC] count, erythrocyte sedimentation rate [ESR], C-reactive protein [CRP]), and DNI were measured. WBC, CRP, ESR and DNI were higher in APN than in lower UTI (p P P P P
- Published
- 2017
132. Sliced Costochondral Chip Grafts in Posttraumatic Enophthalmos Correction
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Tae Hoon Kim, Ie Hyon Park, Sa Hyeok Hong, and Seok Chan Eun
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Adult ,Male ,medicine.medical_specialty ,Ribs ,Dissection (medical) ,Ophthalmologic Surgical Procedures ,030230 surgery ,Enophthalmos ,03 medical and health sciences ,0302 clinical medicine ,medicine ,Perichondrium ,Humans ,Surgery, Plastic ,Orbital Fractures ,Diplopia ,business.industry ,Cartilage ,Eyelids ,General Medicine ,Middle Aged ,Costal cartilage ,medicine.disease ,eye diseases ,Surgery ,Costal Cartilage ,medicine.anatomical_structure ,Otorhinolaryngology ,Patient Satisfaction ,030220 oncology & carcinogenesis ,Female ,Eyelid ,medicine.symptom ,business ,Orbit ,Orbit (anatomy) ,Follow-Up Studies - Abstract
BACKGROUND Posttraumatic enophthalmos is a relatively common problem following orbitozygomatic fractures. However, inadequate long-term results are frequently observed due to the difficulty of performing intraoperative fine adjustments to soft-tissue volume and orbital size and gradual absorption of some grafted materials. Here, the authors describe an efficient method of enophthalmos correction using sliced costochondral bone and cartilage combination grafts. METHODS From 2005 to 2011, the authors corrected enophthalmos in 12 patients using sliced costochondral grafts. The mean follow-up period was 13 months. For costochondral graft harvest, an approximately 5-cm skin incision was made directly above the seventh costal cartilage, the perichondrium was peeled back, and a small piece of rib bone and costal cartilage was harvested from the anterior part of the seventh rib bone and cartilage and cut into 2-mm-thick slices. A subciliary and/or transcaruncular incision was made in the affected side eyelid to expose the operating field, subperiosteal dissection was performed in the orbit and orbital floor. The cartilage chips were gradually grafted onto the dissected areas from the posterior orbit. RESULTS Aesthetically satisfactory results were obtained in all patients. No complications in the donor area were observed. Furthermore, no patients experienced a recurrence or deterioration of diplopia over the follow-up period. One patient experienced temporary high intraocular pressure, which spontaneously resolved with medication and eye drops. CONCLUSION The costochondral graft is adequate for the reconstruction of the fracture, easy to obtain, easily adaptable to the orbital walls, and has minimal morbidity at the donor site.
- Published
- 2016
133. Insight into the role of TSLP in inflammatory bowel diseases
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Jae Il Shin, Michael Eisenhut, Dong Yeon Jeong, Jae Hyon Park, and Laurent Peyrin-Biroulet
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0301 basic medicine ,Thymic stromal lymphopoietin ,T cell ,Immunology ,Disease ,Inflammatory bowel disease ,T-Lymphocytes, Regulatory ,Proinflammatory cytokine ,03 medical and health sciences ,0302 clinical medicine ,Mediator ,Th2 Cells ,Thymic Stromal Lymphopoietin ,Immunology and Allergy ,Medicine ,Animals ,Humans ,Receptors, Cytokine ,Eosinophilic esophagitis ,business.industry ,Dendritic Cells ,medicine.disease ,Inflammatory Bowel Diseases ,Ulcerative colitis ,030104 developmental biology ,medicine.anatomical_structure ,Gene Expression Regulation ,Cytokines ,030211 gastroenterology & hepatology ,business ,Signal Transduction - Abstract
Proinflammatory cytokines are thought to modulate pathogeneses of various inflammatory bowel diseases (IBDs). Thymic stromal lymphopoietin (TSLP), which has been studied in various allergic diseases such as asthma, atopic dermatitis (AD) and eosinophilic esophagitis (EoE), has been less considered to be involved in IBDs. However, mucosal dendritic cells (DCs) induced by various cytokines including TSLP were reported to cause polarization of T cell toward Th2 response, the differentiation of regulatory T-cell (Treg), and secretion of IgA by B cells. In this review, we discuss the concept that decreased TSLP has the potential to accelerate the development of Th1 response dominant diseases such as the Crohn's disease (CD) while increased TSLP has the potential to lead to a development of Th2 cell dominant diseases such the ulcerative colitis (UC). To examine TSLP's role as a potential determining factor for differentiating UC and CD, we analyzed the effects of other genes regulated by TSLP in regards to the UC and CD pathogeneses using data from online open access resources such as NetPath, GeneMania, and the String database. Our findings indicate that TSLP is a key mediator in the pathogenesis of IBDs and that further studies are needed to evaluate its role.
- Published
- 2016
134. From cell biology to immunology: Controlling metastatic progression of cancer via microRNA regulatory networks
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Evropi Theodoratou, George A. Calin, Jae Hyon Park, and Jae Il Shin
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0301 basic medicine ,Immunology ,Cell ,Cancer metastasis ,Cancer ,Clinical settings ,Review ,Biology ,Bioinformatics ,medicine.disease ,Metastasis ,03 medical and health sciences ,030104 developmental biology ,medicine.anatomical_structure ,Oncology ,microRNA ,medicine ,Immunology and Allergy ,Cancer biology - Abstract
Recently, the study of microRNAs has expanded our knowledge of the fundamental processes of cancer biology and the underlying mechanisms behind tumor metastasis. Extensive research in the fields of microRNA and its novel mechanisms of actions against various cancers has more recently led to the trial of a first cancer-targeted microRNA drug, MRX34. Yet, these microRNAs are mostly being studied and clinically trialed solely based on the understanding of their cell biologic effects, thus, neglecting the important immunologic effects that are sometimes opposite of the cell biologic effects. Here, we summarize both the cell biologic and immunologic effects of various microRNAs and discuss the importance of considering both effects before using them in clinical settings. We stress the importance of understanding the miRNA's effect on cancer metastasis from a “systems” perspective before developing a miRNA-targeted therapeutic in treating cancer metastasis.
- Published
- 2016
135. Task Optimization for Spot-Welding by a Multiple Robot System Using Evolutionary Algorithm
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Jinhan Jeong and Jahng-Hyon Park
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Robotic systems ,Computer science ,Evolutionary algorithm ,Systems engineering ,Survivability ,Spot welding ,health care economics and organizations ,Research center - Abstract
This work was supported by the research fund of Survivability Technology Defence Research Center of the Agency for Defence Development of Korea (No. UD150013ID).
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- 2016
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136. Results from South Korea’s 2018 Report Card on Physical Activity for Children and Youth
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Hyon Park, Sang Hwa Lee, Youngwon Kim, Bumjo Oh, Chung Gun Lee, Hyun Joo Kang, Soo Jung Park, Sang Hoon Suh, Yewon Yu, J. Lim, SoJung Lee, Deok Hwan Lee, Eun-Young Lee, Mi Seong Yu, Han Joo Lee, Yoonkyung Song, Wook Song, Yu Sun Jin, Justin Y. Jeon, Se Jung Park, Jung Woo Oh, and Yeon Soo Kim
- Subjects
03 medical and health sciences ,medicine.medical_specialty ,0302 clinical medicine ,Family medicine ,medicine ,Physical activity ,MEDLINE ,Orthopedics and Sports Medicine ,030229 sport sciences ,030212 general & internal medicine ,Psychology ,Report card - Published
- 2018
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137. Association between interleukin-4 gene polymorphisms and intracerebral haemorrhage in Korean population
- Author
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Soo-Joong Kim, Mi-Ju Kim, Hyon Park, Dong Hwan Yun, Seung Don Yoo, J.-H. Chung, Dong Hwan Kim, Hyoung-Geun Kim, Jong Woo Kim, Yong Seol Jeong, Hyun-Kyung Park, Jin San Lee, and Sungwook Kang
- Subjects
medicine.medical_specialty ,business.industry ,Immunology ,Haplotype ,Case-control study ,Single-nucleotide polymorphism ,General Medicine ,medicine.disease ,Gastroenterology ,nervous system diseases ,Surgery ,Polymorphism (computer science) ,Internal medicine ,Genetics ,medicine ,cardiovascular diseases ,business ,Molecular Biology ,Gene ,Stroke ,Allele frequency ,Genetics (clinical) ,Interleukin 4 - Abstract
Interleukin-4 (IL4) polymorphisms (rs2243250, rs2070874) were analysed in Korean patients with ischaemic stroke (IS) (n=119) and intracerebral haemorrhage (ICH) (n=79), and age-matched controls (n =267, IS; n=401, ICH) using direct sequencing. Both single nucleotide polymorphisms and their haplotypes were associated with ICH, but not IS.
- Published
- 2011
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138. Toll-like receptor 1 gene polymorphisms in childhood IgA nephropathy: a case-control study in the Korean population
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J.-H. Chung, Jin San Lee, Sungwook Kang, Hyun-Kyung Park, Hyon Park, Jin-Tae Suh, Cho Bs, Mi-Ju Kim, and Hahn Wh
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Immunology ,Haplotype ,Case-control study ,Single-nucleotide polymorphism ,General Medicine ,Odds ratio ,Biology ,urologic and male genital diseases ,medicine.disease ,Nephropathy ,Genotype ,Genetics ,medicine ,Missense mutation ,Allele ,Molecular Biology ,Genetics (clinical) - Abstract
Summary Toll-like receptors (TLRs) are innate immune mediators that stimulate nuclear factor kappa B and the inflammatory cytokines. TLR1 is expressed in renal tubular epithelial cells when the kidney is injured, but the role of TLR1 gene in glomerulonephritis has not been clearly elucidated. We aimed to investigate the association of TLR1 polymorphisms with immunoglobulin A nephropathy (IgAN) in children. One hundred and ninety pediatric patients with biopsy-proven IgAN and 283 healthy control subjects were enrolled. Two single nucleotide polymorphisms of TLR1 gene [rs4833095 (missense, Asn248Ser) and rs5743557 (promoter, −414C/T)] were selected and genotyped by direct sequencing. For rs4833095, the C/T genotype in the codominant model (vs. the T/T genotype) [odds ratio (OR) = 2.11, 95% confidence interval (CI): 1.21–3.69, P = 0.009] and the genotype containing C allele (C/T and C/C) in the dominant model (vs. the T/T genotype) (OR = 1.97, 95% CI: 1.16–3.34, P = 0.012) were associated with an increased risk of IgAN. For rs5743557, the T/T genotype in the codominant model (vs. the C/C genotype) (OR = 1.74, 95% CI: 1.02–2.96, P = 0.041) appeared to be associated with IgAN risk. In haplotype analysis, the CT haplotype revealed an association with IgAN (codominant model, OR = 1.38, 95% CI: 1.06–1.80, P = 0.017; dominant model, OR = 1.76, 95% CI: 1.16–2.67, P = 0.008). After Bonferroni correction, the association of the genotypes of rs4833095 and the CT haplotype with IgAN risk remained significant. These findings suggest that TLR1 gene polymorphisms may affect IgAN susceptibility in Korean children.
- Published
- 2010
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139. Genetic variations in ATP2B1, CSK, ARSG and CSMD1 loci are related to blood pressure and/or hypertension in two Korean cohorts
- Author
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Lee Jy, Ji-Eun Lim, Bermseok Oh, Kyung-Won Hong, Sue Yun Hwang, Hyun-Seok Jin, Go Mj, Cho Ys, Sang Hwa Lee, Han Bg, and Hyon Park
- Subjects
Adult ,Male ,Blood Pressure ,Single-nucleotide polymorphism ,Polymorphism, Single Nucleotide ,Body Mass Index ,CSK Tyrosine-Protein Kinase ,Cohort Studies ,Plasma Membrane Calcium-Transporting ATPases ,Asian People ,Risk Factors ,Proto-Oncogene Proteins ,Blood plasma ,Genetic variation ,Internal Medicine ,Humans ,Medicine ,SNP ,Genetic Predisposition to Disease ,Aged ,Arylsulfatases ,Genetic association ,Genetics ,Korea ,business.industry ,Tumor Suppressor Proteins ,Membrane Proteins ,Middle Aged ,Protein-Tyrosine Kinases ,src-Family Kinases ,Blood pressure ,Genetic Loci ,Case-Control Studies ,Hypertension ,Cohort ,Female ,ATP2B1 ,business ,Genome-Wide Association Study - Abstract
Blood pressure, one of the important vital signs, is affected by multiple genetic and environmental factors. Recently, several genome-wide association (GWA) studies have successfully identified genetic factors that influence blood pressure and hypertension risk. In this study, we report results of the Korean Association REsource (KARE, 8842 subjects) GWA study on blood pressure and hypertension risk. In all, 10 single-nucleotide polymorphisms (SNPs) that showed significant association with hypertension were further analysed for replication associations in the Health2 project (7861 subjects). Among these 10 SNPs, 3 were replicated in the Health2 cohort for an association with systolic or diastolic blood pressure. The most significant SNP (rs17249754 located in ATPase, Ca(++) transporting, plasma membrane 1 (ATP2B1)) has been previously reported, and the other two SNPs are rs1378942 in the c-src tyrosine kinase (CSK) gene and rs12945290 in the arylsulphatase G (ARSG) gene. An additional hypertension case-control study confirmed that rs17249754 (in ATP2B1) increases hypertension risk in both the KARE and Health2 (meta-analysis, P-value=4.25 x 10(-9)) cohorts. One more SNP, rs995322, located in the CUB and Sushi multiple domains 1 (CSMD1), is also associated with increased risk of hypertension (meta-analysis, P-value=1.00 x 10(-4)). Despite the difficulty of obtaining replication results for a complex trait genetic association between blood pressure and hypertension, we were able to identify consistent genetic factors in both the Korean cohorts in ATP2B1, CSK, ARSG and CSMD1 genes.
- Published
- 2009
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140. Color Correction by Estimation of Dominant Chromaticity in Multi-Scaled Retinex
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Yeong-Ho Ha, In-Su Jang, and Kee-Hyon Park
- Subjects
Mathematics::Combinatorics ,Channel (digital image) ,Color constancy ,business.industry ,Image quality ,media_common.quotation_subject ,Color correction ,General Chemistry ,Atomic and Molecular Physics, and Optics ,Computer Science Applications ,Electronic, Optical and Magnetic Materials ,Computer Science::Computer Vision and Pattern Recognition ,Distortion ,Contrast (vision) ,Computer vision ,Artificial intelligence ,Imaging science ,Chromaticity ,business ,Mathematics ,media_common - Abstract
In image capture a scene with nonuniform illumination has an influence on the image quality, especially the contrast and detail in dark regions. Generally, the tone curve or histogram of an image is modified to improve the contrast and detail, yet this is in- sufficient as the intensity and chromaticity of the illumination vary with geometric position. Thus, the multi-scaled retinex algorithm has been proposed, where the influence of nonuniform illumination is reduced by partitioning the original image using local average im- ages that are estimated based on Gaussian filtering of the original image. However, the multi-scaled retinex algorithm produces color distortion as the local average images are independently estimated for each channel. In particular, if the chromatic distribution of the original image is not uniform and is dominated by a certain chroma- ticity, the local average image includes not only the intensity and chromaticity of the illumination but also the dominant chromaticity through the Gaussian filtering, thereby distorting the color. Accord- ingly, this article proposes a multi-scaled retinex using a modified local average image to reduce the color distortion by the dominant chromaticity of the original image. As with the multi-scaled retinex algorithm, the local average image is obtained through Gaussian filtering of the original image. The local average image is then di- vided by the average chromaticity value of the original image to reduce the influence of the dominant chromaticity. However, be- cause the average chromaticity value includes the dominant chro- maticity of the original image and the chromaticity of the illumination, the chromaticity removed from the illumination in the local average image needs to be compensated. Therefore, the chromaticity of the illumination is estimated based on the chromaticity of the highlight regions in the original image. The chromaticity of the local average image is then modified by the estimated chromaticity. In experi- ments, the proposed method was found to improve local contrast and reduce the color distortion. © 2009 Society for Imaging Science and Technology. DOI: 10.2352/J.ImagingSci.Technol.2009.53.5.050502
- Published
- 2009
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141. LOCATION ESTIMATION OF MOBILE SYSTEMS USING PASSIVE RFID TAGS IN AN INDOOR ENVIRONMENT
- Author
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Yong-Kwan Ji and Jahng-Hyon Park
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Orientation (computer vision) ,business.industry ,Computer science ,Real-time computing ,General Physics and Astronomy ,Statistical and Nonlinear Physics ,Computer Science Applications ,Computational Theory and Mathematics ,Position (vector) ,Embedded system ,Radio-frequency identification ,Antenna (radio) ,business ,Estimation methods ,Mathematical Physics - Abstract
This paper presents methods of localization of mobile systems using recent Radio Frequency Identification (RFID) technology. We consider an indoor environment where RFID tags are implanted along the wall or in objects in the room. If the absolute position and orientation of a tag are read by an RF reader, a mobile system can estimate its location using the information saved in the tags. A reader-tag model is obtained through experiments in order to derive relative positions and orientations between an antenna and an RFID tag. To estimate the location, we propose two estimation methods. One uses a single RFID tag and the other uses multi-RFID tags. Experimental results show that the proposed methods can provide good performance for mobile system localization in an indoor environment.
- Published
- 2009
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142. Neurotransmitter detection by enzyme-immobilized CNT-FET
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Joon-Bong Park, Sujin Choi, Ji-Eun Lim, Hyon Park, Seunghun Hong, and Gihyun Lee
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Transistor ,Glutamate receptor ,General Physics and Astronomy ,Conductance ,Nanotechnology ,Carbon nanotube ,law.invention ,chemistry.chemical_compound ,Ethanolamine ,chemistry ,law ,Biophysics ,General Materials Science ,Neurotransmitter ,Selectivity ,Linker - Abstract
Glutamate is the principal excitatory neurotransmitter in the brain, and its excessive release plays a key role in neuronal death associated with a wide range of neural disorders. Real time monitoring of extracellular glutamate levels would be very helpful in understanding the excitotoxic process of neurotransmitters, as well as brain injury during or after surgery. In order to detect l -glutamate, we immobilized l -glutamate oxidase (GLOD) on carbon nanotube (CNT) network junctions by a non-covalent functionalized method to preserve their electronic characteristics. After immobilizing GLOD on the CNT network, the excess reactive groups of linker molecule remaining on its surface were deactivated and blocked by ethanolamine. The electrical property of the GLOD-immobilized CNT network transistor was characterized as source–drain current that depended on liquid gate voltage. From the changes in the I sd vs. V g plot about the CNT network transistor before and after the immobilization of GLOD, we confirmed that GLOD immobilization decreased the conductance of CNT network junctions, regardless of the sign on the net charge in the protein. The real time electronic response of the GLOD-coated CNT network transistor was conducted with a glutamate standard solution in vitro and the 11 vessel occlusion (11VO) rat model in vivo . The ultrahigh sensitivity, selectivity, and fast response time of GLOD-immobilized CNT-FET could provide great potential for the real time electronic detection of extracellular glutamate levels in the brain.
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- 2009
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143. Cell Selectivity of Arenicin-1 and Its Derivative with Two Disulfide Bonds
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Song Yub Shin, Kyung-Soo Hahm, Jin-Kyoung Kim, Ju-Un Lee, Yoonkyung Park, Ka Hyon Park, Yangmee Kim, and Jee-Young Lee
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chemistry.chemical_classification ,chemistry.chemical_compound ,chemistry ,Stereochemistry ,Disulfide bond ,Structure–activity relationship ,Peptide ,General Chemistry ,Antibacterial activity ,Cell selectivity ,Derivative (chemistry) ,Bacterial cell structure - Abstract
209-214]. Our previous study on AR-1 and its linearderivative showed that disulfide bridge and the amphipat hic â-sheet structure of the AR-1 play important rolesin their biological activities. AR-1 ha s high antibacterial activity but it also displays hemolytic activity againsthuman red blood cells. In order to develop more potent and more bacterial cell selective peptide, we designedand synthesized a new derivative, AR-1-C (RW
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- 2008
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144. Bacterial selectivity and plausible mode of antibacterial action of designed Pro-rich short model antimicrobial peptides
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Ka Hyon Park, Kyung-Soo Hahm, II-Seon Park, Song Yub Shin, and Yoonkyung Park
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Pharmacology ,chemistry.chemical_classification ,Liposome ,Organic Chemistry ,Antimicrobial peptides ,RNA ,Peptide ,General Medicine ,Biology ,Biochemistry ,chemistry.chemical_compound ,Membrane ,chemistry ,Structural Biology ,Drug Discovery ,Indolicidin ,Molecular Medicine ,Selectivity ,Molecular Biology ,DNA - Abstract
To develop novel Pro-rich model AMPs with shorter length and higher bacterial selectivity/therapeutic index (TI) than natural AMP, indolicidin, we synthesized a series of undodecapeptides derived from the sequence XXPXXPWXPXX-NH2 (X indicates Leu or Lys) with different ratios of Lys and Leu residues. Several Pro-rich model peptides (K7WP3, K6WL1P3, K5WL2P3-1, K5WL2P3-2, and K4WL3P3) had approximate 8- to 11-fold higher bacterial selectivity/TI compared to indolicidin. These peptides selectively bind to negatively charged liposomes (EYPG/EYPG; 7:3, w/w) mimicking bacterial membranes. Their high selectivity to negatively charged phospholipids corresponds well with their high bacterial selectivity. Indolicidin showed almost complete depolarization of the cytoplasmic membrane of Staphylococcus aureus and dye-leakage from negatively charged liposomes at 10 µM, whereas all of Pro-rich model peptides had very little activity in these assays even at 80 µM, as observed in buforin 2. These results suggest that the ultimate target of our designed Pro-rich model peptides is probably the intracellular components (e.g. protein, DNA or RNA) rather than the cytoplasmic membranes. Collectively, our designed Pro-rich short model peptides appear to be excellent candidates for future development as a novel antimicrobial agent. Copyright © 2008 European Peptide Society and John Wiley & Sons, Ltd.
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- 2008
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145. Targeting MicroRNAs Involved in the BDNF Signaling Impairment in Neurodegenerative Diseases
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Hwa Jeong You, Alejandro Lucia, Helios Pareja-Galeano, Jae Il Shin, and Jae Hyon Park
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0301 basic medicine ,medicine.medical_specialty ,Neurology ,Central nervous system ,Enfermedad del sistema nervioso ,Biology ,Genetic therapy ,03 medical and health sciences ,Cellular and Molecular Neuroscience ,0302 clinical medicine ,Neurotrophic factors ,microRNA ,medicine ,Humans ,Brain-derived neurotrophic factor ,Regulation of gene expression ,Brain-Derived Neurotrophic Factor ,Neurodegenerative Diseases ,Genetic Therapy ,Enfermedades neurodegenerativas ,MicroRNAs ,030104 developmental biology ,medicine.anatomical_structure ,Gene Expression Regulation ,Molecular Medicine ,Signal transduction ,Neuroscience ,030217 neurology & neurosurgery ,Signal Transduction - Abstract
Neurodegenerative diseases are becoming an ever-increasing problem in aging populations. Low levels of brain-derived neurotrophic factor (BDNF) have previously been associated with the pathogenesis of numerous neurodegenerative diseases. Recently, microRNAs (miRNAs) have been proposed as potential novel therapeutic targets for treating various diseases of the central nervous system (CNS), and interestingly, few studies have reported several miRNAs that downregulate the expression levels of BDNF. However, substantial challenges exist when attempting to translate these findings into practical anti-miRNA therapeutics, especially when the targets remain inside the CNS. Thus, in this review, we summarize the specific molecular mechanisms by which several miRNAs negatively modulate the expressions of BDNF, address the potential clinical difficulties that can be faced during the development of anti-miRNA-based therapeutics and propose strategies to overcome these challenges. Sin financiación 3.287 JCR (2016) Q2, 98/259 Neurosciences 1.488 SJR (2016) Q1, 43/183 Molecular Medicine; Q2, 42/92 Cellular and Molecular Neuroscience, 42/166 Neurology No data IDR 2016 UEM
- Published
- 2016
146. Banding-Artifact Reduction Using an Improved Threshold Scaling Function in Multitoning with Stochastic Screen
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In-Su Jang, Yeong-Ho Ha, Oh-Seol Kwon, Tae-Yong Park, and Kee-Hyon Park
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Banding Artifact ,Pixel ,Threshold limit value ,Comparison results ,Color reproduction ,General Chemistry ,Thresholding ,Atomic and Molecular Physics, and Optics ,Computer Science Applications ,Electronic, Optical and Magnetic Materials ,Imaging science ,Algorithm ,Scaling ,Mathematics - Abstract
In the bilevel halftoning technique using a stochastic screen, an input image value is thresholded by a corresponding screen value (threshold) to represent two printable output levels, i.e. black and white. This halftoning method can be easily extended to multilevel halftoning (multitoning) by scaling the threshold before thresholding. However, if a general transformation function is used for the scaling of the threshold, banding artifacts can appear due to similar dot distributions near the printable output levels, thus result- ing in discontinuity in the smooth tone transition region. Accordingly, in order to reduce such banding artifacts, this paper proposes a multitoning method that arranges the gray-level distribution by con- trolling the blending proportion of the adjacent output pixels based on improved threshold scaling functions. The proposed method con- sists of two thresholding processes to print the majority pixels and the adjacent output pixels. For input pixels within the neighborhood of the printable output levels, the majority pixels are first placed according to the point-wise comparison result between the fixed in- put value and the corresponding threshold value that is scaled by a general threshold scaling function. This allows the proportion of ma- jority pixels to be controlled using the fixed input value. The adjacent output pixels are introduced to preserve a gray-level balance near the printable output levels based on the comparison result between the input value and the corresponding threshold value that is scaled by an improved threshold scaling function. The gray-level distribu- tion across the banding regions is affected by two control factors of the improved threshold scaling function that control the blending point of the adjacent output pixels. To prove that the improved threshold scaling function, with specific factor values, could achieve a smoother visual transition, several observers investigated the gray-level distribution around the printable output levels. The experi- mental results confirmed that the proposed method was able to re- duce the banding artifacts in both gray and color images and a better color reproduction was produced. © 2007 Society for Imaging Science and Technology. DOI: 10.2352/J.ImagingSci.Technol.200751:6502
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- 2007
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147. Antimicrobial and Anti-Inflammatory Activities of a Leu/Lys-Rich Antimicrobial Peptide with Phe-Peptoid Residues
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Ka Hyon Park, Yong Hai Nan, Il-Seon Park, Yoonkyung Park, Kyung-Soo Hahm, Young Jin Jeon, and Song Yub Shin
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Erythrocytes ,medicine.drug_class ,Phenylalanine ,Molecular Sequence Data ,Anti-Inflammatory Agents ,Peptide ,Microbial Sensitivity Tests ,Gram-Positive Bacteria ,Nitric Oxide ,Biochemistry ,Bacterial cell structure ,Anti-inflammatory ,Microbiology ,HeLa ,Mice ,Peptoids ,chemistry.chemical_compound ,Anti-Infective Agents ,Leucine ,Structural Biology ,Gram-Negative Bacteria ,medicine ,Animals ,Humans ,Cytotoxic T cell ,Amino Acid Sequence ,chemistry.chemical_classification ,biology ,Lysine ,Peptoid ,General Medicine ,Fluoresceins ,Antimicrobial ,biology.organism_classification ,chemistry ,Cytoplasm ,NIH 3T3 Cells ,Peptides ,HeLa Cells - Abstract
To develop a novel cell-selective antimicrobial peptide with potent anti-inflammatory activity as well as high bacterial cell selectivity, we synthesized a Leu/Lys-rich model peptide, KLW-f (KWKKLLKKfLKLfKKLLK-NH(2)) containing two Phe-peptoid residues in its middle position. KLW-f exhibited high antimicrobial activity (the MIC range: 0.5 approximately 2.0microM) against the tested six bacterial cells. In contrast, KLW-f was no cytotoxic to human red blood cells and HeLa and NIH-3T3 cells. KLW-f caused no or little dye leakage from EYPE/EYPG (7:3, w/w) vesicles (bacterial membrane-mimicking environments), indicating its bacterial-killing action is probably not due to permeabilization/disruption of bacterial cytoplasmic membranes. Furthermore, KLW-f induced a significant inhibition in LPS-stimulated NO production from mouse macrophage RAW264.7 cells at 10microg/ml. Taken together, our results suggest that KLW-f appear to have promising therapeutic potential for future development as a novel antisepsis agent as well as antimicrobial agent.
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- 2007
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148. XPS study of NiO Growth on Ag(100)
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Shi-Jin Seong, Han-Na Hwang, Soo-Hyon Park, C. C. Hwang, Seolun Yang, Jeong-Gyun Kim, H.G. Min, and Young Jun Chang
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Materials science ,X-ray photoelectron spectroscopy ,Materials Science (miscellaneous) ,Optimum growth ,Non-blocking I/O ,Analytical chemistry ,Substrate (chemistry) ,Partial pressure ,Electrical and Electronic Engineering ,Physical and Theoretical Chemistry ,Condensed Matter Physics ,Spectral line - Abstract
We have researched the chemical defects of NiO ultrathin films grown on Ag(001) by x-ray photoelectron spectroscopy. In particular, O 1s and Ni 2p spectra were analyzed consistently with control film thickness, partial pressure and substrate temperature. As a result, we could identify each chemical defect. In addition, we suggest the optimum growth condition to minimize the defect density.
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- 2007
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149. Substitution of the leucine zipper sequence in melittin with peptoid residues affects self-association, cell selectivity, and mode of action
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Song Yub Shin, Yun Mi Song, Yoonkyung Park, Il-Seon Park, Jae Il Kim, Ka Hyon Park, Sung-Tae Yang, Wan Long Zhu, and Kyung-Soo Hahm
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Leucine zipper ,Erythrocytes ,Stereochemistry ,Molecular Sequence Data ,Antimicrobial peptides ,Biophysics ,Tetrazolium Salts ,Peptide ,Protein Engineering ,Biochemistry ,Protein Structure, Secondary ,Melittin ,Peptoids ,chemistry.chemical_compound ,Protein structure ,Self-association ,Cell selectivity ,Animals ,Humans ,Amino Acid Sequence ,Amino Acids ,chemistry.chemical_classification ,Leucine Zippers ,Bacteria ,Circular Dichroism ,Cell Membrane ,Peptoid ,Cell Biology ,Melitten ,Amino acid ,Peptoid residue ,Thiazoles ,chemistry ,Leucine ,Antimicrobial peptide ,HeLa Cells - Abstract
Melittin (ME), a non-cell-selective antimicrobial peptide, contains the leucine zipper motif, wherein every seventh amino acid is leucine or isolucine. Here, we attempted to generate novel cell-selective peptides by substituting amino acids in the leucine zipper sequence of ME with peptoid residues. We generated a series of ME analogues by replacing Leu-6, Lue-13 and Ile-20 with Nala, Nleu, Nphe, or Nlys, and we examined their secondary structure, self-association activity, cell selectivity and mode of action. Circular dichroism spectroscopy indicated that the substitutions disrupt the α-helical structure of ME in micelles of sodium dodecyl sulfate and on negatively charged and zwitterionic phospholipid vesicles. Substitution by Nleu, Nphe, or Nlys but not Nala disturbed the self-association in an aqueous environment, interaction with zwitterionic membranes, and toxicity to mammalian cells of ME but did not affect the interaction with negatively charged membranes or antibacterial activity. Notably, peptides with Nphe or Nlys substitution had the highest therapeutic indices, consistent with their lipid selectivity. In addition, all of peptoid residue-containing ME analogues had little or no ability to induce membrane disruption, membrane depolarization and lipid flip-flop. Taken together, our studies indicate that substitution of the leucine zipper motif in ME with peptoid residues increases its selectivity against bacterial cells by impairing self-association activity and changes its mode of antibacterial action from membrane-targeting mechanism to possible intracellular targeting mechanism. Furthermore, our ME analogues especially those with Nleu, Nphe, or Nlys substitutions, may be therapeutically useful antimicrobial peptides.
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- 2007
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150. Surface Reflectance Estimation Using the Principal Components of Similar Colors
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Cheol-Hee Lee, Kee-Hyon Park, Yeong-Ho Ha, and Oh-Seol Kwon
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education.field_of_study ,Spectral power distribution ,business.industry ,Population ,Standard illuminant ,General Chemistry ,Color space ,Reflectivity ,Atomic and Molecular Physics, and Optics ,Computer Science Applications ,Electronic, Optical and Magnetic Materials ,Principal component analysis ,ColorChecker ,Computer vision ,Artificial intelligence ,Imaging science ,business ,education ,Mathematics - Abstract
The sensor response of a camera can be represented as the stimulus multiplied by the spectral distribution of an ambient illuminant, the surface reflectance of an object, and camera sensi- tivity. Surface reflectance is one of the most significant factors that indicates an object's color; therefore its estimation has received widespread attention. Among conventional methods for estimating surface reflectance, principal component analysis (PCA) has an ad- vantage because it uses only one set of principal components for an entire reflectance population. There are limitations, however, in es- timating all reflectance using this PCA method with only one set of principal components. In this article, an algorithm is proposed to estimate surface reflectance by using principal components deter- mined by subgroups with similar colors, which are classified from the entire reflectance population. In order to compose a subgroup with similar colors, the Macbeth ColorChecker is utilized to obtain initial representative surface reflectance values for an entire reflec- tance population; then the Munsell chips are divided into subgroups with different principal components. Moreover, initial representatives have to be modified to avoid biased representations for the popula- tion because the Macbeth ColorChecker does not provide optimal representations for the entire reflectance population, even though it is evenly spaced in the CIELAB color space. Therefore, the mean value of each subgroup is used to obtain new representatives, and the new subgroups of reflectance are composed by using the Lloyd quantizer design algorithm. Then, the PCA method is applied for the principal components of the subgroup including surface reflectance. To evaluate its performance, the proposed estimation method was compared with that of a conventional three-band principle compo- nent analysis. The proposed method provided better results in its performance. © 2007 Society for Imaging Science and Technology. DOI: 10.2352/J.ImagingSci.Technol.200751:2166
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- 2007
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