70 results on '"Kwon, Sunghoon"'
Search Results
2. A doubly sparse approach for group variable selection.
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Kwon, Sunghoon, Ahn, Jeongyoun, Jang, Woncheol, Lee, Sangin, and Kim, Yongdai
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MATHEMATICAL variables , *GROUP theory , *MATHEMATICAL optimization , *ALGORITHMS , *REGRESSION analysis - Abstract
We propose a new penalty called the doubly sparse (DS) penalty for variable selection in high-dimensional linear regression models when the covariates are naturally grouped. An advantage of the DS penalty over other penalties is that it provides a clear way of controlling sparsity between and within groups, separately. We prove that there exists a unique global minimizer of the DS penalized sum of squares of residuals and show how the DS penalty selects groups and variables within selected groups, even when the number of groups exceeds the sample size. An efficient optimization algorithm is introduced also. Results from simulation studies and real data analysis show that the DS penalty outperforms other existing penalties with finite samples. [ABSTRACT FROM AUTHOR]
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- 2017
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3. A superstructure model of an isolated power supply system using renewable energy: Development and application to Jeju Island, Korea.
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Kwon, Sunghoon, Won, Wangyun, and Kim, Jiyong
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ISOLATED power plants , *POWER resources , *RENEWABLE energy sources , *HEAT storage devices , *ENERGY industries - Abstract
In this study, we aim to develop a superstructure-based optimization model using mixed integer linear programming (MILP) to determine the optimal combination and sizing for a hybrid renewable energy system to be used in an isolated area. The developed model has a three-layered energy structure to reflect the current reality in which energy production and consumption sites are generally separate. A variety of economic factors, including distance between facilities and an installation area, are considered for a more accurate estimation of the total annualized cost. Two types of optimization models, i.e., with and without a battery, are proposed to evaluate the economic and technical effects of a storage device to resolve operation issues caused by intermittent resources. An application case study on Jeju Island, Korea, confirms that the proposed model is suitable for decision making at the planning stage of a renewable energy system. [ABSTRACT FROM AUTHOR]
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- 2016
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4. Homogeneity detection for the high-dimensional generalized linear model.
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Jeon, Jong-June, Kwon, Sunghoon, and Choi, Hosik
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LINEAR statistical models , *REGRESSION analysis , *NUMERICAL analysis , *ESTIMATION theory , *MATHEMATICAL statistics - Abstract
We propose to use a penalized estimator for detecting homogeneity of the high-dimensional generalized linear model. Here, the homogeneity is a specific model structure where regression coefficients are grouped having exactly the same value in each group. The proposed estimator achieves weak oracle property under mild regularity conditions and is invariant to the choice of reference levels when there are categorical covariates in the model. An efficient algorithm is also provided. Various numerical studies confirm that the proposed penalized estimator gives better performance than other conventional variable selection estimators when the model has homogeneity. [ABSTRACT FROM AUTHOR]
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- 2017
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5. The use of random-effect models for high-dimensional variable selection problems.
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Kwon, Sunghoon, Oh, Seungyoung, and Lee, Youngjo
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RANDOM variables , *DIMENSIONAL analysis , *PROBLEM solving , *GENERALIZATION , *NUMBER theory , *SAMPLE size (Statistics) - Abstract
We study the use of random-effect models for variable selection in high-dimensional generalized linear models where the number of covariates exceeds the sample size. Certain distributional assumptions on the random effects produce a penalty that is non-convex and unbounded at the origin. We introduce a unified algorithm that can be applied to various statistical models including generalized linear models. Simulation studies and data analysis are provided. [ABSTRACT FROM AUTHOR]
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- 2016
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6. Excitation-intensity-dependent charge carrier dynamics in thienylenevinylene-phthalimide copolymer based thin polymer films.
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Kim, In-Sik, Kwon, Sunghoon, Kim, Juhwan, Kim, Dong-Yu, and Ko, Do-Kyeong
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EXCITON theory , *CHARGE carriers , *COPOLYMERS , *THIN films , *POLYMER films , *ANNIHILATIONISM (Christianity) , *HETEROJUNCTIONS , *RECOMBINATION (Chemistry) - Abstract
The ultrafast charge carrier dynamics of alkyl-substituted thienylenevinylene and phtalimide-based donor/acceptor (D/A) alternating copolymer (PTVPhI-Eh) as well as PTVPhI-Eh:PC 71 BM bulk heterojunctions (BHJs) with and without processing 1-chloronaphthalene (CN) additive have been studied by means of a femtosecond transient absorption (TA) measurement. Photo induced absorption of the D/A copolymer was prohibited under certain excitation intensity. In both BHJs, we observed fast decay components (∼1 ps) which are assisted by high order process such as exciton-charge annihilation (ECA) or exciton–exciton annihilation (EEA) under high excitation intensity. In the CN-treated BHJ, however, the fast decay components were shortened to <1 ps because of increased ECA or EEA rate. In addition, the CN-treated BHJ showed slow geminate recombination time which indicates reduced carrier loss. Consequently, we could confirm excited stated properties of the copolymer and ultrafast spectroscopic evidences of enhancement in power conversion efficiency related with the inclusion of solvent additive to BHJ. [ABSTRACT FROM AUTHOR]
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- 2015
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7. A modified local quadratic approximation algorithm for penalized optimization problems.
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Lee, Sangin, Kwon, Sunghoon, and Kim, Yongdai
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APPROXIMATION algorithms , *MATHEMATICAL optimization , *INTEGER approximations , *PIECEWISE constant approximation , *MAXIMA & minima - Abstract
In this paper, we propose an optimization algorithm called the modified local quadratic approximation algorithm for minimizing various ℓ 1 -penalized convex loss functions. The proposed algorithm iteratively solves ℓ 1 -penalized local quadratic approximations of the loss function, and then modifies the solution whenever it fails to decrease the original ℓ 1 -penalized loss function. As an extension, we construct an algorithm for minimizing various nonconvex penalized convex loss functions by combining the proposed algorithm and convex concave procedure, which can be applied to most nonconvex penalty functions such as the smoothly clipped absolute deviation and minimax concave penalty functions. Numerical studies show that the algorithm is stable and fast for solving high dimensional penalized optimization problems. [ABSTRACT FROM AUTHOR]
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- 2016
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8. Moderately clipped LASSO.
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Kwon, Sunghoon, Lee, Sangin, and Kim, Yongdai
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OPERATOR theory , *LINEAR systems , *MACHINE theory , *NUMERICAL analysis , *MATHEMATICAL variables - Abstract
The least absolute shrinkage and selection operator (LASSO) has been widely used in high-dimensional linear regression models. However, it is known that the LASSO selects too many noisy variables. In this paper, we propose a new estimator, the moderately clipped LASSO (MCL), that deletes noisy variables successively without sacrificing prediction accuracy much. Various numerical studies are done to illustrate superiority of the MCL over other competitors. [ABSTRACT FROM AUTHOR]
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- 2015
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9. Global optimality of nonconvex penalized estimators.
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Kim, Yongdai and Kwon, Sunghoon
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NONCONVEX programming , *CHEBYSHEV approximation , *MATHEMATICAL variables , *ESTIMATION theory , *PROBABILITY theory - Abstract
Nonconvex penalties such as the smoothly clipped absolute deviation or minimax concave penalties have desirable properties such as the oracle property, even when the dimension of the predictive variables is large. However, checking whether a given local minimizer has such properties is not easy since there can be many local minimizers. In this paper, we give sufficient conditions under which a local minimizer is unique, and show that the oracle estimator becomes the unique local minimizer with probability tending to one. [ABSTRACT FROM PUBLISHER]
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- 2012
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10. QMAC-DST for Rapid Detection of Drug Resistance in Pulmonary Tuberculosis Patients: A Multicenter Pre–Post Comparative Study.
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Kwak, Nakwon, Lee, Sangyeop, Kim, Suyeoun, Song, Eunbee, Yim, Jae-Joon, Shim, Tae Sun, Jeon, Doosoo, Jhun, Byung Woo, Seok, Kwang-Hyuk, Kim, Saerom, Kwon, Sunghoon, and Mok, Jeongha
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TUBERCULOSIS patients , *TUBERCULOSIS , *DRUG resistance , *TURNAROUND time , *COMPARATIVE studies - Abstract
Background/Objectives: This study explores the impact of QMAC-DST, a rapid, fully automated phenotypic drug susceptibility test (pDST), on the treatment of tuberculosis (TB) patients. Methods: This pre–post comparative study, respectively, included pulmonary TB patients who began TB treatment between 1 December 2020 and 31 October 2021 (pre-period; pDST using the Löwenstein–Jensen (LJ) DST (M-kit DST)) and between 1 November 2021 and 30 September 2022 (post-period; pDST using the QMAC-DST) in five university-affiliated tertiary care hospitals in South Korea. We compared the turnaround times (TATs) of pDSTs and the time to appropriate treatment for patients whose anti-TB drugs were changed based on these tests between the groups. All patients were permitted to use molecular DSTs (mDSTs). Results: A total of 182 patients (135 in the M-kit DST group and 47 in the QMAC-DST group) were included. The median TAT was 36 days for M-kit DST (interquartile range (IQR), 30–39) and 12 days for QMAC-DST (IQR, 9–15), with the latter being significantly shorter (p < 0.001). Of the total patients, 10 (5.5%) changed their anti-TB drugs based on the mDST or pDST results after initiating TB treatment (8 in the M-kit DST group and 2 in the QMAC-DST group). In the M-kit DST group, three (37.5%) patients changed anti-TB drugs based on the pDST results. In the QMAC-DST group, all changes were due to mDST results; therefore, calculating the time to appropriate treatment for patients whose anti-TB drugs were changed based on pDST results was not feasible. In the QMAC-DST group, 46.8% of patients underwent the first-line line probe assay compared to 100.0% in the M-kit DST group (p < 0.001), indicating that rapid QMAC-DST results provide quicker assurance of the ongoing treatment by confirming susceptibility to the current anti-TB drugs. Conclusions: QMAC-DST delivers pDST results more rapidly than LJ-DST, ensuring faster confirmation for the current treatment regimen. [ABSTRACT FROM AUTHOR]
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- 2024
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11. Quadratic approximation on SCAD penalized estimation
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Kwon, Sunghoon, Choi, Hosik, and Kim, Yongdai
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QUADRATIC fields , *APPROXIMATION theory , *ESTIMATION theory , *STATISTICAL smoothing , *REGRESSION analysis , *NUMERICAL analysis , *SIMULATION methods & models , *REAL-time computing - Abstract
Abstract: In this paper, we propose a method of quadratic approximation that unifies various types of smoothly clipped absolute deviation (SCAD) penalized estimations. For convenience, we call it the quadratically approximated SCAD penalized estimation (Q-SCAD). We prove that the proposed Q-SCAD estimator achieves the oracle property and requires only the least angle regression (LARS) algorithm for computation. Numerical studies including simulations and real data analysis confirm that the Q-SCAD estimator performs as efficient as the original SCAD estimator. [Copyright &y& Elsevier]
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- 2011
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12. An area-efficient VLSI architecture of a reed-solomon...
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Kwon, Sunghoon and Shin, Hyunchul
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VERY large scale circuit integration , *DECODERS (Electronics) , *REED-Solomon codes - Abstract
Presents an area-efficient very large-scale integration (VLSI) architecture of a reed-solomon (RS) decoder/encoder for digital video-cassette recorder (VCR). Three main features of the proposed decoder/encoder; Overview of the proposed RS decoder/encoder; RS decoder/encoder architectures; Comparison of the circuit sizes of RS decoder/encoder.
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- 1997
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13. Embedded pilot tracking tone generation for digital VCRs.
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Shin, Hyunchul and Kwon, Sunghoon
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VIDEOCASSETTE recorders - Abstract
Reports on embedded pilot tracking tone generation for digital videocassette recorders. Frequency characteristics; Track format; Correctness of the calculate-and-correct method; Simulation results.
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- 1996
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14. Multiclass sparse logistic regression for classification of multiple cancer types using gene expression data
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Kim, Yongdai, Kwon, Sunghoon, and Heun Song, Seuck
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GENE expression , *CANCER diagnosis , *GENETIC regulation , *PROGNOSIS - Abstract
Abstract: Monitoring gene expression profiles is a novel approach to cancer diagnosis. Several studies have showed that the sparse logistic regression is a useful classification method for gene expression data. Not only does it give a sparse solution with high accuracy, it provides the user with explicit probabilities of classification apart from the class information. However, its optimal extension to more than two classes is not obvious. In this paper, we propose a multiclass extension of sparse logistic regression. Analysis of five publicly available gene expression data sets shows that the proposed method outperforms the standard multinomial logistic model in prediction accuracy as well as gene selectivity. [Copyright &y& Elsevier]
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- 2006
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15. Recent Advances in Polymer Additive Engineering for Diagnostic and Therapeutic Hydrogels.
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Bae, Sang-Wook, Kim, Jiyun, and Kwon, Sunghoon
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POLYMERS , *DATA warehousing , *POINT-of-care testing , *ENGINEERING , *NUCLEIC acids , *HYDROGELS - Abstract
Hydrogels are hydrophilic polymer materials that provide a wide range of physicochemical properties as well as are highly biocompatible. Biomedical researchers are adapting these materials for the ever-increasing range of design options and potential applications in diagnostics and therapeutics. Along with innovative hydrogel polymer backbone developments, designing polymer additives for these backbones has been a major contributor to the field, especially for expanding the functionality spectrum of hydrogels. For the past decade, researchers invented numerous hydrogel functionalities that emerge from the rational incorporation of additives such as nucleic acids, proteins, cells, and inorganic nanomaterials. Cases of successful commercialization of such functional hydrogels are being reported, thus driving more translational research with hydrogels. Among the many hydrogels, here we reviewed recently reported functional hydrogels incorporated with polymer additives. We focused on those that have potential in translational medicine applications which range from diagnostic sensors as well as assay and drug screening to therapeutic actuators as well as drug delivery and implant. We discussed the growing trend of facile point-of-care diagnostics and integrated smart platforms. Additionally, special emphasis was given to emerging bioinformatics functionalities stemming from the information technology field, such as DNA data storage and anti-counterfeiting strategies. We anticipate that these translational purpose-driven polymer additive research studies will continue to advance the field of functional hydrogel engineering. [ABSTRACT FROM AUTHOR]
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- 2022
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16. Mapping cancer biology in space: applications and perspectives on spatial omics for oncology.
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Lee, Sumin, Kim, Gyeongjun, Lee, JinYoung, Lee, Amos C., and Kwon, Sunghoon
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CYTOLOGY , *TUMOR microenvironment , *ONCOLOGY , *BIOLOGY - Abstract
Technologies to decipher cellular biology, such as bulk sequencing technologies and single-cell sequencing technologies, have greatly assisted novel findings in tumor biology. Recent findings in tumor biology suggest that tumors construct architectures that influence the underlying cancerous mechanisms. Increasing research has reported novel techniques to map the tissue in a spatial context or targeted sampling-based characterization and has introduced such technologies to solve oncology regarding tumor heterogeneity, tumor microenvironment, and spatially located biomarkers. In this study, we address spatial technologies that can delineate the omics profile in a spatial context, novel findings discovered via spatial technologies in oncology, and suggest perspectives regarding therapeutic approaches and further technological developments. [ABSTRACT FROM AUTHOR]
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- 2024
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17. New closed‐form efficient estimator for multivariate gamma distribution.
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Jang, Yu‐Hyeong, Zhao, Jun, Kim, Hyoung‐Moon, Yu, Kyusang, Kwon, Sunghoon, and Kim, SungHwan
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GAMMA distributions , *ASYMPTOTIC normality , *NEWTON-Raphson method - Abstract
Maximum likelihood estimation is used widely in classical statistics. However, except in a few cases, it does not have a closed form. Furthermore, it takes time to derive the maximum likelihood estimator (MLE) owing to the use of iterative methods such as Newton–Raphson. Nonetheless, this estimation method has several advantages, chief among them being the invariance property and asymptotic normality. Based on the first approximation to the solution of the likelihood equation, we obtain an estimator that has the same asymptotic behavior as the MLE for multivariate gamma distribution. The newly proposed estimator, denoted as MLECE$$ {\mathrm{MLE}}_{\mathrm{CE}} $$, is also in closed form as long as the n$$ \sqrt{n} $$‐consistent initial estimator is in the closed form. Hence, we develop some closed‐form n$$ \sqrt{n} $$‐consistent estimators for multivariate gamma distribution to improve the small‐sample property. MLECE$$ {\mathrm{MLE}}_{\mathrm{CE}} $$ is an alternative to MLE and performs better compared to MLE in terms of computation time, especially for large datasets, and stability. For the bivariate gamma distribution, the MLECE$$ {\mathrm{MLE}}_{\mathrm{CE}} $$ is over 130 times faster than the MLE, and as the sample size increasing, the MLECE$$ {\mathrm{MLE}}_{\mathrm{CE}} $$ is over 200 times faster than the MLE. Owing to the instant calculation of the proposed estimator, it can be used in state–space modeling or real‐time processing models. [ABSTRACT FROM AUTHOR]
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- 2023
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18. Erratum to: A doubly sparse approach for group variable selection.
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Kwon, Sunghoon, Ahn, Jeongyoun, Jang, Woncheol, Lee, Sangin, and Kim, Yongdai
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GROUP theory , *MATHEMATICAL variables - Published
- 2017
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19. The QPLEX™ Plus Assay Kit for the Early Clinical Diagnosis of Alzheimer's Disease.
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Na, Hunjong, Shin, Ki Young, Lee, Dokyung, Yoon, Changsik, Han, Sun-Ho, Park, Jong-Chan, Mook-Jung, Inhee, Jang, Jisung, and Kwon, Sunghoon
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ALZHEIMER'S disease , *EARLY diagnosis , *POSITRON emission tomography , *MILD cognitive impairment , *ANGIOTENSIN converting enzyme , *NEUROFIBRILLARY tangles , *PRESENILINS - Abstract
We recently developed a multiplex diagnostic kit, QPLEX™ Alz plus assay kit, which captures amyloid-β1-40, galectin-3 binding protein, angiotensin-converting enzyme, and periostin simultaneously using microliters of peripheral blood and utilizes an optimized algorithm for screening Alzheimer's disease (AD) by correlating with cerebral amyloid deposition. Owing to the demand for early AD detection, we investigate the potential of our kit for the early clinical diagnosis of AD. A total of 1395 participants were recruited, and their blood samples were analyzed with the QPLEX™ kit. The average of QPLEX™ algorithm values in each group increased gradually in the order of the clinical progression continuum of AD: cognitively normal (0.382 ± 0.150), subjective cognitive decline (0.452 ± 0.130), mild cognitive impairment (0.484 ± 0.129), and AD (0.513 ± 0.136). The algorithm values between each group showed statistically significant differences among groups divided by Mini-Mental State Examination and Clinical Dementia Rating. The QPLEX™ algorithm values could be used to distinguish the clinical continuum of AD or cognitive function. Because blood-based diagnosis is more accessible, convenient, and cost- and time-effective than cerebral spinal fluid or positron emission tomography imaging-based diagnosis, the QPLEX™ kit can potentially be used for health checkups and the early clinical diagnosis of AD. [ABSTRACT FROM AUTHOR]
- Published
- 2023
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20. A robust support vector machine for labeling errors.
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Choi, Hosik, Kim, Yongdai, Kwon, Sunghoon, and Park, Changyi
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SUPPORT vector machines , *OUTLIERS (Statistics) , *MACHINE learning , *LOSS functions (Statistics) , *CONVEX domains - Abstract
Support vectormachine (SVM) is sparse in that its classifier is expressed as a linear combination of only a few support vectors (SVs). Whenever an outlier is included as an SV in the classifier, the outlier may have serious impact on the estimated decision function. In this article, we propose a robust loss function that is convex. Our learning algorithm is more robust to outliers than SVM. Also the convexity of our loss function permits an efficient solution path algorithm. Through simulated and real data analysis, we illustrate that our method can be useful in the presence of labeling errors. [ABSTRACT FROM AUTHOR]
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- 2017
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21. Novel THPO variant in hereditary thrombocytopenia: A potential candidate variant for predisposition to myeloid neoplasm.
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Kwon, Seok Ryun, Kim, Man Jin, Lee, Young-eun, Yun, Jiwon, Jeong, Da-jeong, Park, Jae Hyeon, Kwon, Sunghoon, and Lee, Dong Soon
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THROMBOCYTOPENIA , *CONGENITAL disorders , *THROMBOPOIETIN receptors , *IDIOPATHIC thrombocytopenic purpura , *BONE marrow , *MYELODYSPLASTIC syndromes , *TUMORS - Abstract
Hereditary thrombocytopenia is a heterogeneous group of congenital disorders with a wide range of symptoms depending on the severity of platelet dysfunction or thrombocytopenia. Because of its clinical phenotypes and the bone marrow morphology associated with this condition, hereditary thrombocytopenia can be misdiagnosed as primary immune thrombocytopenia and myelodysplastic syndrome. Therefore, genetic evidence is necessary for the accurate diagnosis of hereditary thrombocytopenia. Refractory cytopenia of childhood is a subgroup of myelodysplastic syndrome that was added to the World Health Organization classification in 2008. To investigate the germline and somatic variants associated with refractory cytopenia of childhood, we performed targeted multigene sequencing in three patients with refractory cytopenia of childhood. Of the three patients, one progressed from megakaryocytic hypoplasia with thrombocytopenia, and targeted multigene sequencing revealed THPO variants in this patient and his sister. We propose that the monoallelic deletion of THPO is a potential candidate for germline predisposition to myeloid malignancy. [ABSTRACT FROM AUTHOR]
- Published
- 2022
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22. I-LIFT (image-based laser-induced forward transfer) platform for manipulating encoded microparticles.
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Lee, Sumin, Lee, Wooseok, Lee, Amos Chungwon, Nam, Juhong, Lee, JinYoung, Kim, Hamin, Jeong, Yunjin, Yeom, Huiran, Kim, Namphil, Song, Seo Woo, and Kwon, Sunghoon
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INDEXING - Abstract
Encoded microparticles have great potential in small-volume multiplexed assays. It is important to link the micro-level assays to the macro-level by indexing and manipulating the microparticles to enhance their versatility. There are technologies to actively manipulate the encoded microparticles, but none is capable of directly manipulating the encoded microparticles with homogeneous physical properties. Here, we report the image-based laser-induced forward transfer system for active manipulation of the graphically encoded microparticles. By demonstrating the direct retrieval of the microparticles of interest, we show that this system has the potential to expand the usage of encoded microparticles. [ABSTRACT FROM AUTHOR]
- Published
- 2022
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23. Evaluation of the GenoType® MTBDR sl assay in Korean patients with MDR or XDR tuberculosis.
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Jeong, Hyun Yong, Kim, Haeun, Kwon, Sunghoon, and Ryoo, Sungweon
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GENETICS of tuberculosis , *TUBERCULOSIS diagnosis , *MICROBIAL sensitivity tests , *DRUG resistance in bacteria , *KOREANS , *NUCLEOTIDE sequencing , *DISEASES - Abstract
BackgroundThis study used the GenoType® MTBDRslassay (MTBDRsl, Hain Lifescience, Nehren, Germany), an assay for anti-tuberculosis drug susceptibility testing, for the detection of resistance of 40 tuberculosis strains to fluroquinolones (FLQ), injectable drugs (amikacin or capreomycin) and ethambutol to identify multi-drug resistant and extensively drug-resistant tuberculosis patients previously identified by solid drug susceptibility test (DST).MethodsThese tuberculosis strains were analysed by both DNA sequencing and conventional drug susceptibility testing on solid medium.ResultsThe overall agreement rates of the MTBDRslassay and phenotypic drug susceptibility testing for the detection of ofloxacin (OXF), moxifloxacin (MXF), amikacin (AMK), capreomycin (CPM) and ethambutol (EMB) susceptibility in clinical strains were 87.5% (35/40), 87.5% (35/40), 97.5% (39/40), 60.0% (24/40) and 65.0% (26/40), respectively.ConclusionsThis study reconfirmed 37 extensively drug-resistant tuberculosis strains using the MTBDRslassay and these strains were verified by phenotypic drug susceptibility testing. After identification with the MTBDRslassay, the results were analysed by DNA sequencing with specific primers. From the various mutations identified in the DNA sequencing results, this study found new mutations that characterised EMB-resistant strains, namely, R507K and G406T mutations, which had not been previously reported. [ABSTRACT FROM AUTHOR]
- Published
- 2016
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24. Ampoule‐Like Microvolume Containers with Transparent Code for Easy‐to‐Use and Space‐Saving Storage of Small‐Volume Biospecimens.
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Kim, Hyeli, Choi, Yeongjae, Lee, Amos C., Bae, Junghyun, Yoon, Jinsik, Kim, Kibeom, Park, Cheolheon, Jeong, Hyun Yong, Lee, Gi Yoon, Choi, Hansol, Kwon, Sunghoon, and Park, Wook
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TWO-dimensional bar codes , *CONTAINERS , *STORAGE - Abstract
The importance of storing, transporting, and managing biospecimens for analysis and research has increased. Biospecimens, such as DNA and cells, have a volume of several micrometers or less for practical storage, management, and usage, and high space efficiency can be achieved if stored in an appropriate indexed container. However, although previous studies have highlighted the importance of small‐volume biospecimens, containers suitable for easily handling microscale samples and space‐saving storage are lacking. Here, easy‐to‐use and space‐saving biospecimen storage with ampoule‐like microvolume containers and transparent codes are introduced. The high‐durability epoxy‐based containers are suitable for storing and using microscale biospecimens, and protecting internal biospecimens from the external environment. To identify the biospecimens, microsized transparent QR codes on microparticles for indexing sample information and storage conditions are fabricated via optofluidic maskless lithography, enabling on‐demand fabrication. Both the microsized QR code and microvolume container are highly transparent, making the observation of even minimal volumes of internal material convenient. Similar to an ampoule, the microvolume container can be broken with a needle or blade to release the biospecimen. The storage efficiency of the container is verified by storing and releasing DNA, antibiotics, and cells. This container will save space for biospecimens in biobank systems. [ABSTRACT FROM AUTHOR]
- Published
- 2022
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25. One-step assembly of barcoded planar microparticles for efficient readout of multiplexed immunoassay.
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Bae, Sangwook, Lee, Daewon, Na, Hunjong, Jang, Jisung, and Kwon, Sunghoon
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MASS production - Abstract
Barcoded planar microparticles are suitable for developing cost-efficient multiplexed assays, but the robustness and efficiency of the readout process still needs improvement. Here, we designed a one-step microparticle assembling chip that produces efficient and accurate multiplex immunoassay readout results. Our design was also compatible with injection molding for mass production. [ABSTRACT FROM AUTHOR]
- Published
- 2022
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26. Purification of multiplex oligonucleotide libraries by synthesis and selection.
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Choi, Hansol, Choi, Yeongjae, Choi, Jaewon, Lee, Amos Chungwon, Yeom, Huiran, Hyun, Jinwoo, Ryu, Taehoon, and Kwon, Sunghoon
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Complex oligonucleotide (oligo) libraries are essential materials for diverse applications in synthetic biology, pharmaceutical production, nanotechnology and DNA-based data storage. However, the error rates in synthesizing complex oligo libraries can be substantial, leading to increment in cost and labor for the applications. As most synthesis errors arise from faulty insertions and deletions, we developed a length-based method with single-base resolution for purification of complex libraries containing oligos of identical or different lengths. Our method—purification of multiplex oligonucleotide libraries by synthesis and selection—can be performed either step-by-step manually or using a next-generation sequencer. When applied to a digital data-encoded library containing oligos of identical length, the method increased the purity of full-length oligos from 83% to 97%. We also show that libraries encoding the complementarity-determining region H3 with three different lengths (with an empirically achieved diversity >106) can be simultaneously purified in one pot, increasing the in-frame oligo fraction from 49.6% to 83.5%. Accurate oligonucleotide libraries are produced by synthesis and selection. [ABSTRACT FROM AUTHOR]
- Published
- 2022
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27. Micro‐Concentrator Photovoltaics Using Fluidic Self‐Assembly Technology.
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Cho, Seongkyu, Choi, Wonseok, Han, Sunghoon, Kim, Junhoi, Lee, Amos C., Kim, Su Deok, Song, Seo Woo, Kim, Changsoon, Lee, Daewon, and Kwon, Sunghoon
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SOLAR batteries , *SOLAR concentrators , *PHOTOVOLTAIC power generation , *GALLIUM arsenide , *SOLAR energy industries , *SOLAR cells , *MICROFLUIDICS , *MICROTECHNOLOGY - Abstract
This paper is the first to report a simple and cost‐effective method for modularizing an array of gallium arsenide (GaAs) solar cells on a plastic circuit board using fluidic self‐assembly (FSA) technology and the combination thereof with a polymer lens array to implement micro‐concentrator photovoltaics (micro‐CPV). Using FSA and low‐melting‐point solder, the GaAs cells are successfully self‐assembled into a 2D array in 1 min. Micro‐CPVs consisting of 36 and 256 cells are manufactured by aligning a polymer concentrator fabricated by a drop‐on‐demand droplet dispensed lens array mold on the solar cell array. The micro‐CPVs generate 21.31 and 112.96 mW of power, respectively, under 1 sun AM 1.5G illumination. In each module, only 1.69 and 2.27 mm2 of GaAs are used for producing 1 mW; in other words, the implemented micro‐CPV platform consumes 4.21 and 3.14 times less material than a flat‐panel GaAs array. The proposed method for implementing a GaAs‐based solar cell array enables the efficient fabrication of a compact micro‐CPV with a thickness of only 4 mm owing to the absence of a cooling module. This technology is expected to potentially increase the practical usability of III‐V compound solar cells in the energy industry. [ABSTRACT FROM AUTHOR]
- Published
- 2021
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28. Fabrication of membrane-type microvalves in rectangular microfluidic channels viaseal photopolymerizationElectronic supplementary information (ESI) available: Fig. S1, S2 and supplementary movie. See DOI: 10.1039/c005173j.
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Park, Wook, Han, Sangkwon, and Kwon, Sunghoon
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PHOTOPOLYMERIZATION , *MICROFLUIDIC devices , *OLIGOMERS , *PHOTOLITHOGRAPHY , *POLYMERS , *SEALING (Technology) - Abstract
Rectangular fluidic channels have rarely been used in microfluidic devices which use PDMS membrane-type microvalves, since the rectangular channel shape does not perfectly match the round shape of the membrane deformation. We present a polymer sealing method to fabricate PDMS membrane-type microvalves for rectangular microchannels. After fabricating the microfluidic device, photocurable oligomer is introduced into the fluidic channel and gas pressure is applied to the pneumatic channel to deform the membrane. The polymer seal is then locally polymerized by photolithography producing a structure matching the shape of the deformed membrane curvature. We compare the flow leakage between the membrane-type microvalve with and without a polymer seal. We also demonstrate a micropump and droplet generator using this embedded polymer membrane-type microvalve in a rectangular microfluidic channel. This polymeric seal technique enables the use of easily fabricated rectangular channel membrane microvalves with all the functionality of their curved channel counterparts with negligible flow leakage. [ABSTRACT FROM AUTHOR]
- Published
- 2010
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29. Performance of QuantaMatrix Microfluidic Agarose Channel system integrated with mycobacteria growth indicator tube liquid culture.
- Author
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Kim, Hyejin, Lee, Sangyeop, Jo, EunJi, Kim, Suyeoun, Kim, Haeun, Kim, Eun-Geun, Kwon, Sunghoon, and Shin, Soyoun
- Subjects
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MYCOBACTERIUM tuberculosis , *AGAROSE , *MYCOBACTERIA , *DNA sequencing , *TUBERCULOSIS , *TURNAROUND time , *DNA probes - Abstract
The QuantaMatrix Microfluidic Agarose Channel (QMAC) system was used for rapid drug susceptibility testing (DST). Here, we performed DST using QMAC integrated with the mycobacteria growth indicator tube (MGIT) liquid culture employing a specially designed cross agarose channel for the tuberculosis chip. MGIT-, QMAC-, and Löwenstein–Jensen (LJ)-DSTs were performed using 13 drugs. The protocol for QMAC-DST was optimized using the inoculum obtained after the disaggregation of Mycobacterium tuberculosis clumps in MGIT culture. The completion times of QMAC-DST and MGIT-DST were analyzed, and the results of all three DSTs were compared. Discrepant results were analyzed using line probe assays and DNA sequencing. Nontuberculous mycobacteria were distinguished using the ρ-nitrobenzoic acid inhibition test. The overall agreement rate of QMAT-DST and LJ-DST was 97.0% and that of QMAT-DST and MGIT-DST was 86.3%. An average turnaround time for DST was 5.4 days, which was considerably less than the time required for MGIT-DST. The overall time required to obtain DST results using QMAC-DST integrated with MGIT culture was an average of 18.6 days: 13.2 days for culture and identification and 5.4 days for DST. Hence, QMAC-DST integrated with liquid culture can be used to perform DSTs with short turnaround times and effective detection. Key points: • QMAC system can simultaneously perform phenotypic DST with 13 anti-TB drugs and PNB. • An optimized DST protocol led to a marked decrease in clumping in MGIT culture. • QMAC system integrated with MGIT liquid culture system reduced the turnaround time. [ABSTRACT FROM AUTHOR]
- Published
- 2021
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30. Phenotype-based single cell sequencing identifies diverse genetic subclones in CD133 positive cancer stem cells.
- Author
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Min, Dong-Wook, Kim, Hwang-Phill, Kim, Jinhyun, Wen, Xianyu, Kim, Sungsik, Cho, Young-Won, Lim, Yoojoo, Song, Sang-Hyun, Han, Sae-Won, Kwon, Sunghoon, Kang, Gyeong Hoon, and Kim, Tae-You
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CANCER stem cells , *CELL analysis , *CELL populations , *METASTASIS , *CANCER relapse , *FROZEN tissue sections , *COLON cancer - Abstract
Tumor heterogeneity is one of the ongoing huddles in the field of colon cancer therapy. It is evident that there are countless clones which exhibit different phenotypes and therefore, single cell analysis is inevitable. Cancer stem cells (CSCs) are rare cell population within tumor which is known to function in cancer metastasis and recurrence. Although there have been trials to prove intra-tumoral heterogeneity using single cell sequencing, that of CSCs has not been clearly elucidated. Here, we articulate the presence of heterogeneous subclones within CD133 positive cancer stem cells through single cell sequencing. As a proof of principle, we performed phenotype-based high-throughput laser isolation and single cell sequencing (PHLI-seq) of CD133 positive cells in a frozen tumor tissue obtained from a patient with colorectal cancer. The result proved that CD133 positive cells were shown to be heterogeneous both in copy number and mutational profiles. Single cancer stem cell specific mutations such as RNF144A, PAK2, PARP4, ADAM21, HYDIN, KRT38 and CELSR1 could be also detected in liver metastatic tumor of the same patient. Collectively, these data suggest that single cell analysis used to spot subclones with genetic variation within rare population, will lead to new strategies to tackle colon cancer metastasis. • Single cell sequencing of CD133 positive cancer stem cells were carried out. • A novel sequencing method called PHLI-seq was used for this study. • CD133 positive cancer stem cells consisted of clones with different mutations. • One of the subsets harbored mutations which were found in liver metastatic tissue. [ABSTRACT FROM AUTHOR]
- Published
- 2021
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31. Quadratic approximation for nonconvex penalized estimations with a diverging number of parameters
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Lee, Sangin, Kim, Yongdai, and Kwon, Sunghoon
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APPROXIMATION theory , *ESTIMATION theory , *STATISTICAL models , *NUMERICAL analysis , *DEVIATION (Statistics) , *MATHEMATICAL statistics - Abstract
Abstract: We propose an approximated penalized estimator (APE) that covers various statistical models and nonconvex penalties including the smoothly clipped absolute deviation (SCAD) penalty () as a special case. The APE achieves the oracle property with a diverging number of parameters which extends the results of . Several numerical studies confirm the theoretical results. [Copyright &y& Elsevier]
- Published
- 2012
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32. Gene selection and prediction for cancer classification using support vector machines with a reject option
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Choi, Hosik, Yeo, Donghwa, Kwon, Sunghoon, and Kim, Yongdai
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TUMOR classification , *SUPPORT vector machines , *GENE expression , *ALGORITHMS , *COMPARATIVE studies , *MACHINE learning - Abstract
Abstract: In cancer classification based on gene expression data, it would be desirable to defer a decision for observations that are difficult to classify. For instance, an observation for which the conditional probability of being cancer is around 1/2 would preferably require more advanced tests rather than an immediate decision. This motivates the use of a classifier with a reject option that reports a warning in cases of observations that are difficult to classify. In this paper, we consider a problem of gene selection with a reject option. Typically, gene expression data comprise of expression levels of several thousands of candidate genes. In such cases, an effective gene selection procedure is necessary to provide a better understanding of the underlying biological system that generates data and to improve prediction performance. We propose a machine learning approach in which we apply the penalty to the SVM with a reject option. This method is referred to as the SVM with a reject option. We develop a novel optimization algorithm for this SVM, which is sufficiently fast and stable to analyze gene expression data. The proposed algorithm realizes an entire solution path with respect to the regularization parameter. Results of numerical studies show that, in comparison with the standard SVM, the proposed method efficiently reduces prediction errors without hampering gene selectivity. [Copyright &y& Elsevier]
- Published
- 2011
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33. Performance of the QPLEX™ Alz plus assay, a novel multiplex kit for screening cerebral amyloid deposition.
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Park, Jong-Chan, Jung, Keum Sim, Kim, Jiyeong, Jang, Ji Sung, Kwon, Sunghoon, Byun, Min Soo, Yi, Dahyun, Byeon, Gihwan, Jung, Gijung, Kim, Yu Kyeong, Lee, Dong Young, Han, Sun-Ho, and Mook-Jung, Inhee
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AMYLOID , *RECEIVER operating characteristic curves , *LOGISTIC regression analysis , *POSITRON emission tomography , *BLOOD plasma - Abstract
Background: Alzheimer's disease (AD) is an irreversible neurodegenerative disease characterized by the hallmark finding of cerebral amyloid deposition. Many researchers have tried to predict the existence of cerebral amyloid deposition by using easily accessible blood plasma samples, but the effectiveness of such strategies remains controversial. Methods: We developed a new multiplex kit, the QPLEX™ Alz plus assay kit, which uses proteomics-based blood biomarkers to prescreen for cerebral amyloid deposition. A total of 300 participants who underwent Pittsburgh compound B (PiB)-positron emission tomography (PET) which allows imaging of cerebral amyloid deposition were included in this study. We compared the levels of QPLEX™ biomarkers between patients who were classified as PiB-negative or PiB-positive, regardless of their cognitive function. Logistic regression analysis followed by receiver operating characteristic (ROC) curve analysis was performed. The kit accuracy was tested using a randomized sample selection method. Results: The results obtained using our assay kit reached 89.1% area under curve (AUC) with 80.0% sensitivity and 83.0% specificity. Further validation of the QPLEX™ Alz plus assay kit using a randomized sample selection method showed an average accuracy of 81.5%. Conclusions: Our QPLEX™ Alz plus assay kit provides preliminary evidence that it can be used as blood marker to predict cerebral amyloid deposition but independent validation is needed. [ABSTRACT FROM AUTHOR]
- Published
- 2021
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34. A high-throughput cell culture system based on capillary and centrifugal actions for rapid antimicrobial susceptibility testing.
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Lim, Taegeun, Kim, Eun-Geun, Choi, Jungil, and Kwon, Sunghoon
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MICROBIAL sensitivity tests , *CELL culture , *DRUG resistance in bacteria , *LABS on a chip , *OPTICAL measurements - Abstract
Antibiotic resistance is a global threat to modern society. Rapid determination of suitable antibiotics that inhibit bacterial growth can effectively reduce antibiotic resistance and improve clinical treatment. The conventional methods of antimicrobial susceptibility testing (AST) depend on optical density measurements, which require long-time incubation. Various kinds of rapid AST systems which utilize various technologies from the field of lab on a chip have promised a great reduction in measurement time, but cannot achieve high-throughput, user-friendly testing due to the complexity of the testing system. Here, we introduce a capillary and centrifuge-based rapid AST system that reduces the time of loading the sample and culture media while achieving a high-throughput testing capacity. The capability of the proposed system is validated in a systematic analysis that includes sample loading characteristics and AST trials with standard strains. The proposed system provides a useful tool for drug testing in cell-culture systems with user-friendly and high-throughput analysis. [ABSTRACT FROM AUTHOR]
- Published
- 2020
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35. Prospective evaluation of a rapid antimicrobial susceptibility test (QMAC-dRAST) for selecting optimal targeted antibiotics in positive blood culture.
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Kim, Jeong-Han, Kim, Taek Soo, Jung, Hyun gul, Kang, Chang Kyung, Jun, Kang-Il, Han, Sangkwon, Kim, Dong Young, Kwon, Sunghoon, Song, Kyoung-Ho, Choe, Pyeong Gyun, Bang, Ji Hwan, Kim, Eu Suk, Park, Sang Won, Kim, Hong Bin, Kim, Nam Joong, Park, Wan Beom, and Oh, Myoung-don
- Subjects
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MICROBIAL sensitivity tests , *ANTIBIOTICS , *MATRIX-assisted laser desorption-ionization , *GRAM'S stain , *THERAPEUTICS - Abstract
Objectives: MALDI-TOF MS has been successfully used for empirical antibiotic selection. However, limited data are available regarding the usefulness of MALDI-TOF MS in common resistant organisms compared with rapid antimicrobial susceptibility testing (AST). We prospectively evaluated the usefulness of rapid AST, compared with MALDI-TOF MS, for optimal antibiotic selection by infectious disease (ID) physicians in patients with bacteraemia including polymicrobial infection.Methods: Three hundred and fifty-nine patients with positive blood culture were included for analysis. ID physicians prospectively decided on antibiotic regimens with consensus at each timepoint of receiving results of Gram stain, MALDI-TOF MS and rapid AST, the last of which was performed using QMAC-dRAST.Results: ID physicians with MALDI-TOF MS results chose optimal targeted antibiotics in 255 (71.0%) cases, with appropriate antibiotic selection in 303 (84.4%) cases. The proportion of optimal targeted antibiotic selection and appropriate antibiotic selection was significantly lower for resistant strains than for susceptible strains [62.5% versus 79.2% (P < 0.001) and 68.2% versus 100% (P < 0.001), respectively]. QMAC-dRAST results led to optimal antibiotic treatment in 95 (91.3%) of the 104 cases receiving non-optimal targeted antibiotics. Optimal targeted treatments based on QMAC-dRAST results were possible in 322 (98.2%) of the 328 cases with monobacterial infection and in 345 (96.1%) of the 359 cases with monobacterial and polymicrobial infection.Conclusions: MALDI-TOF MS has a high chance of failure in guiding ID physicians to optimal antibiotics, especially against resistant organisms. With increasingly common resistant organisms, rapid AST is needed to identify optimal targeted antibiotics early in bacteraemia. [ABSTRACT FROM AUTHOR]- Published
- 2019
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36. Author Correction: Evaluating Tumor Evolution via Genomic Profiling of Individual Tumor Spheroids in a Malignant Ascites.
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Kim, Sungsik, Kim, Soochi, Kim, Jinhyun, Kim, Boyun, Kim, Se Ik, Kim, Min A., Kwon, Sunghoon, and Song, Yong Sang
- Published
- 2018
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37. Evaluating Tumor Evolution via Genomic Profiling of Individual Tumor Spheroids in a Malignant Ascites.
- Author
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Kim, Sungsik, Kim, Soochi, Kim, Jinhyun, Kim, Boyun, Kim, Se Ik, Kim, Min A., Kwon, Sunghoon, and Song, Yong Sang
- Published
- 2018
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38. Hierarchical shape-by-shape assembly of microparticles for micrometer-scale viral delivery of two different genes.
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Lee, Daewon, Lee, Amos Chungwon, Han, Sangkwon, Bae, Hyung Jong, Song, Seo Woo, Jeong, Yunjin, Oh, Dong Yoon, Cho, Seongkyu, Kim, Junhoi, Park, Wook, and Kwon, Sunghoon
- Subjects
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TISSUE engineering , *GENE transfection , *VIRAL genetics , *CELL populations , *MICROMETERS - Abstract
Understanding tissue engineering using a bottom-up approach has been hindered by technical limitations because no platform can demonstrate the controlled formation of a heterogeneous population of cells in microscale. Here, we demonstrate hierarchical shape-by-shape assembly of virus-laden particles into larger ones to transfect two different genes on the seeded cells. We show that smaller daughter particles with different sizes and shapes can be assembled into the matching indentations of larger parent particles with different sizes and shapes. Then, we transfected a population of cells with two different gene-transfecting viruses, each of which was laden on the parent or daughter particles. [ABSTRACT FROM AUTHOR]
- Published
- 2018
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39. ELIPatch, a thumbnail-size patch with immunospot array for multiplexed protein detection from human skin surface.
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Oh, Dong Yoon, Na, Hunjong, Song, Seo Woo, Kim, Jinhyun, In, Hyunsoo, Lee, Amos Chungwon, Jeong, Yunjin, Lee, Daewon, Jang, Jisung, and Kwon, Sunghoon
- Subjects
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SKIN physiology , *SKIN proteins , *BIOMARKERS , *IMMUNOASSAY , *MOLECULAR self-assembly , *CYTOKINES , *INTERFERONS - Abstract
Proteins secreted by skin have great potential as biomarkers for interpreting skin conditions. However, inconvenience in handling and bulky size of existing methods are existing limitations. Here, we describe a thumb-nail sized patch with the array of microdisks which captures multiple proteins from the skin surface. Microdisks with antibody on the surface enable multiplexed immunoassay. By self-assembly, microdisks are placed into 2-dimensional arrays on adhesive tape. The proposed Enzyme-Linked Immunospot array on a Patch shows sufficient sensitivity for IL-1α, IL1RA, IL-17A, IFN-g, and TNF-α, while IL-6 and IL-1β are non-detectable in some cases. As demonstrations, we quantified cytokines from different skin regions and volunteers in a high-spatial-resolution. [ABSTRACT FROM AUTHOR]
- Published
- 2018
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40. A Reconfigurable DNA Accordion Rack.
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Choi, Yeongjae, Choi, Hansol, Lee, Hyunung, Kwon, Sunghoon, and Lee, Amos C.
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DNA nanotechnology , *DNA structure , *NANOPORES , *MOLECULAR self-assembly , *TRANSMISSION electron microscopy - Abstract
Abstract: DNA nanostructure‐based mechanical systems that control the distance between elements of interest have demonstrated great potential for various applications, including nanoplasmonic systems, molecular reactors, and other nanotechnology platforms. However, previously reported systems could not collectively manipulate a 2D or 3D nanoscale network of elements to various forms in multiple stages. A reconfigurable DNA accordion rack structure is introduced that is a DNA beam lattice that changes its conformation with a small amount of short‐length DNA locks as the controlling input. The lattice shape of the 2D DNA accordion rack and the diameter and the height of the 3D DNA nanotubular structure made of the DNA accordion rack could be controlled. Furthermore, by sequentially repeating the detachment and the attachment of the different DNA locks using strand displacement, the shape reconfiguration was repeatedly carried out. [ABSTRACT FROM AUTHOR]
- Published
- 2018
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41. A Reconfigurable DNA Accordion Rack.
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Choi, Yeongjae, Choi, Hansol, Lee, Hyunung, Kwon, Sunghoon, and Lee, Amos C.
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ROUTING algorithms , *TRANSMISSION electron microscopy , *DNA analysis , *NANOTUBES , *NUCLEOTIDE sequence , *GEL electrophoresis - Abstract
Abstract: DNA nanostructure‐based mechanical systems that control the distance between elements of interest have demonstrated great potential for various applications, including nanoplasmonic systems, molecular reactors, and other nanotechnology platforms. However, previously reported systems could not collectively manipulate a 2D or 3D nanoscale network of elements to various forms in multiple stages. A reconfigurable DNA accordion rack structure is introduced that is a DNA beam lattice that changes its conformation with a small amount of short‐length DNA locks as the controlling input. The lattice shape of the 2D DNA accordion rack and the diameter and the height of the 3D DNA nanotubular structure made of the DNA accordion rack could be controlled. Furthermore, by sequentially repeating the detachment and the attachment of the different DNA locks using strand displacement, the shape reconfiguration was repeatedly carried out. [ABSTRACT FROM AUTHOR]
- Published
- 2018
- Full Text
- View/download PDF
42. Idiopathic hypereosinophilia is clonal disorder? Clonality identified by targeted sequencing.
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Lee, Jee-Soo, Seo, Heewon, Im, Kyongok, Park, Si Nae, Kim, Sung-Min, Lee, Eun Kyoung, Kim, Jung-Ah, Lee, Joon-hee, Kwon, Sunghoon, Kim, Miyoung, Koh, Insong, Hwang, Seungwoo, Park, Heung-Woo, Kang, Hye-Ryun, Park, Kyoung Soo, Kim, Ju Han, and Lee, Dong Soon
- Subjects
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HYPEREOSINOPHILIC syndrome , *GENE targeting , *EOSINOPHILS , *CELL proliferation , *GENETIC mutation , *NUCLEOTIDE sequencing - Abstract
Idiopathic hypereosinophilia (IHE)/idiopathic hypereosinophilic syndrome (IHES) has been defined by a persistent elevation of the blood eosinophil count exceeding 1.5×103/μL, without evidence of reactive or clonal causes. While T-cell clonality assessment has been recommended for unexplained hypereosinophilia, this approach is not often applied to routine practice in the clinic. We hypothesized that the clonality would exist in a subset of IHE/IHES patients. We aimed to investigate the candidate mutations and T-cell clonality in IHE/IHES and to explore the role of mutations in eosinophil proliferation. We performed targeted capture sequencing for 88 genes using next-generation sequencing, T-cell receptor (TCR) gene rearrangement assays, and pathway network analysis in relation to eosinophil proliferation. By targeted sequencing, 140 variants in 59 genes were identified. Sixteen out of 30 patients (53.3%) harbored at least one candidate mutation. The most frequently affected genes were NOTCH1 (26.7%), SCRIB and STAG2 (16.7%), and SH2B3 (13.3%). Network analysis revealed that our 21 candidate genes (BIRC3, BRD4, CSF3R, DNMT3A, EGR2, EZH2, FAT4, FLT3, GATA2, IKZF, JAK2, MAPK1, MPL, NF1, NOTCH1, PTEN, RB1, RUNX1, TET2, TP53 and WT1) are functionally linked to the eosinophilopoietic pathway. Among the 21 candidate genes, five genes (MAPK1, RUNX1, GATA2, NOTCH1 and TP53) with the highest number of linkages were considered major genes. A TCR assay revealed that four patients (13.3%) had a clonal TCR rearrangement. NOTCH1 was the most frequently mutated gene and was shown to be a common node for eosinophilopoiesis in our network analysis, while the possibility of hidden T cell malignancy was indwelling in the presence of NOTCH1 mutation, though not revealed by aberrant T cell study. Collectively, these results provide new evidence that mutations affecting eosinophilopoiesis underlie a subset of IHE/IHES, and the candidate genes are inferred to act their potential roles in the eosinophilopoietic pathway. [ABSTRACT FROM AUTHOR]
- Published
- 2017
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43. An encoded viral micropatch for multiplex cell-based assays through localized gene delivery.
- Author
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Han, Sangkwon, Bae, Hyung Jong, Kim, Su Deok, Park, Wook, and Kwon, Sunghoon
- Subjects
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HIGH throughput screening (Drug development) , *GENE expression , *G protein coupled receptors , *IMMOBILIZED cells , *FLUORESCENCE - Abstract
The increasing number of potential drug targets and compounds has led to the development of high-throughput cell-based assays. Simultaneous processing of multiple targets in the same experiment based on localized target gene expression is a very efficient strategy for this purpose. To address this need, we present an adenoviral vector-immobilized microparticle with two-dimensional (2D) shape-encoding properties that allows localized patch-like gene delivery to monolayer-cultured cells. This format conveniently achieves multiplexed gene delivery compatible with both high-throughput cellular assays and fluorescence high-content imaging instruments. A multiplex G protein-coupled receptor (GPCR) internalization assay was developed to demonstrate the compatibility of this system with high-throughput image-based cellular assays. [ABSTRACT FROM AUTHOR]
- Published
- 2017
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- View/download PDF
44. Uniform Drug Loading into Prefabricated Microparticles by Freeze-Drying.
- Author
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Song, Seo Woo, Bae, Hyung Jong, Kim, Sudeok, Oh, Dong Yoon, Kim, Okju, Jeong, Yunjin, and Kwon, Sunghoon
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DRUG delivery systems , *FREEZE-drying , *BIOLOGICAL assay , *CAPILLARY flow , *THIN films - Abstract
Microparticle-based drug delivery is a promising technology for small volume bioassay platforms. The general utilization of the drug-loaded microparticles in the in vitro bioassay platforms requires the drug loading method, which should impregnate the general drug types (e.g., water insoluble) with high payload into the variously designed microparticles. Loading the drug into the prefabricated microparticles using solvent evaporation satisfies the requirement. However, similar to the 'coffee-ring effect,' drugs are loaded in a seriously nonuniform manner, caused by the capillary flow during the evaporation process. Here, it is presented that the freeze-drying is an efficient way to load uniform and high amount of the drug into the prefabricated microparticles. It is demonstrated that freezing solvent can block the capillary flow during the solvent removal process, improving the loading uniformity. The delivered amount of drugs is linearly proportional to the initial loading amount of drugs. Also, this drug loading method is shown to be applied to the various drug types and the prefabricated microparticles with different properties. Considering many challenges to suppress the 'coffee-ring effect' that induces nonuniform impregnation/deposition, the proposed concept can be applied not only for microparticle-based drug delivery but also for uniform coating applications (e.g., thin-film coating, DNA/protein microarray). [ABSTRACT FROM AUTHOR]
- Published
- 2017
- Full Text
- View/download PDF
45. Towards encoded particles for highly multiplexed colorimetric point of care autoantibody detection.
- Author
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Svedberg, Gustav, Jeong, Yunjin, Na, Hunjong, Jang, Jisung, Nilsson, Peter, Kwon, Sunghoon, Gantelius, Jesper, and Svahn, Helene Andersson
- Subjects
- *
COLORIMETRIC analysis , *POINT-of-care testing , *DIFFERENTIAL diagnosis , *EMERGENCY medicine , *BIOMARKERS - Abstract
Highly multiplexed point of care tests could improve diagnostic accuracy and differential diagnostic capacity in for instance emergency medicine and low resource environments. Available technology platforms for POC biomarker detection are typically simplex or low-plexed, whereas common lab-based microarray systems allow for the simultaneous detection of thousands of DNA or protein biomarkers. In this study, we demonstrate a novel suspension particle array platform that utilizes 900 μm bricks for POC amenable colorimetric biomarker detection with an encoding capacity of over two million. Due to the mm-scale size, both the lithographic codes and colorimetric signals of individual particles can be visualized using a consumer grade office flatbed scanner, with a potential for simultaneous imaging of around 19 000 particles per scan. The analytical sensitivity of the assay was determined to be 4 ng ml−1 using an antibody model system. As a proof of concept, autoantibodies toward anoctamin 2 were detected in order to discriminate between multiple sclerosis plasma samples and healthy controls with p < 0.0001 and an inter-assay % CV of 9.44%. [ABSTRACT FROM AUTHOR]
- Published
- 2017
- Full Text
- View/download PDF
46. Liquid-capped encoded microcapsules for multiplex assays.
- Author
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Song, Younghoon, Jeong, Yunjin, Kwon, Taehong, Lee, Daewon, Oh, Dong Yoon, Park, Tae-Joon, Kim, Junhoi, Kim, Jiyun, and Kwon, Sunghoon
- Subjects
- *
MOLECULAR capsules , *MICROFLUIDICS , *APOPTOSIS , *GENETIC transduction , *ENZYME inhibitors - Abstract
Although droplet microfludics is a promising technology for handling a number of liquids of a single type of analyte, it has limitations in handling thousands of different types of analytes for multiplex assay. Here, we present a novel “liquid-capped encoded microcapsule”, which is applicable to various liquid format assays. Various liquid drops can be graphically encoded and arrayed without repeated dispensing processes, evaporation, and the risk of cross-contamination. Millions of nanoliter-scale liquids are encapsulated within encoded microcapsules and self-assembled in microwells in a single dispensing process. The graphical code on the microcapsule enables identification of randomly assembled microcapsules in each microwell. We conducted various liquid phase assays including enzyme inhibitor screening, virus transduction, and drug-induced apoptosis tests. The results showed that our liquid handling technology can be utilized widely for various solution phase assays. [ABSTRACT FROM AUTHOR]
- Published
- 2017
- Full Text
- View/download PDF
47. Rapid drug susceptibility test of Mycobacterium tuberculosis using microscopic time-lapse imaging in an agarose matrix.
- Author
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Choi, Jungil, Yoo, Jungheon, Kim, Ki-jung, Kim, Eun-Geun, Park, Kyung, Kim, Hyejin, Kim, Haeun, Jung, Hyunju, Kim, Taeyoung, Choi, Myungjin, Kim, Hee, Ryoo, Sungweon, Jung, Yong-Gyun, and Kwon, Sunghoon
- Subjects
- *
TUBERCULOSIS treatment , *DRUG efficacy , *MICROSCOPY , *AGAROSE , *DRUG resistance in bacteria - Abstract
Tuberculosis (TB) is a major global health problem, and multi-drug-resistant TB (MDR-TB) and extensively drug-resistant TB (XDR-TB) are spreading throughout the world. However, conventional drug susceptibility test (DST) methods, which rely on the detection of the colony formation on a solid medium, require 1-2 months to the result. A rapid and accurate DST is necessary to identify patients with drug-resistant TB and treat them with appropriate drugs. Here, we used microscopic imaging of Mycobacterium tuberculosis (MTB) immobilized in an agarose matrix for a rapid DST. The agarose matrix, which was molded in a microfluidic chip, was inoculated with MTB, and TB drugs in liquid culture medium diffused throughout the agarose to reach the MTB immobilized in the agarose matrix. After the responses of MTB to drugs were tracked with an automated microscopic system, an image-processing program automatically determined the susceptibility and resistance of MTB to specific doses of TB drugs. The automatic DST system was able to assess the drug susceptibility of various drug-resistant clinical TB strains within 9 days with an accuracy comparable to that of conventional method. Our rapid DST method based on microscopic time-lapse imaging greatly reduces the time required for a DST and can be used to rapidly and accurately treat TB patients. [ABSTRACT FROM AUTHOR]
- Published
- 2016
- Full Text
- View/download PDF
48. Evaluation of Penalized and Nonpenalized Methods for Disease Prediction with Large-Scale Genetic Data.
- Author
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Won, Sungho, Choi, Hosik, Park, Suyeon, Lee, Juyoung, Park, Changyi, and Kwon, Sunghoon
- Subjects
- *
GENETICS of disease susceptibility , *HYPERTENSION genetics , *GENETICS of type 2 diabetes , *OBESITY genetics , *SMOKING , *REGRESSION analysis , *DATA analysis , *STATISTICAL models , *DESCRIPTIVE statistics , *GENOTYPES , *GENETICS - Abstract
Owing to recent improvement of genotyping technology, large-scale genetic data can be utilized to identify disease susceptibility loci and this successful finding has substantially improved our understanding of complex diseases. However, in spite of these successes, most of the genetic effects for many complex diseases were found to be very small, which have been a big hurdle to build disease prediction model. Recently, many statistical methods based on penalized regressions have been proposed to tackle the so-called “large P and small N” problem. Penalized regressions including least absolute selection and shrinkage operator (LASSO) and ridge regression limit the space of parameters, and this constraint enables the estimation of effects for very large number of SNPs. Various extensions have been suggested, and, in this report, we compare their accuracy by applying them to several complex diseases. Our results show that penalized regressions are usually robust and provide better accuracy than the existing methods for at least diseases under consideration. [ABSTRACT FROM AUTHOR]
- Published
- 2015
- Full Text
- View/download PDF
49. Shape-encoded silica microparticles for multiplexed bioassays.
- Author
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Kim, Lily Nari, Kim, Mira, Jung, Keumsim, Bae, Hyung Jong, Jang, Jisung, Jung, Yushin, Kim, Jiyun, and Kwon, Sunghoon
- Subjects
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BIOLOGICAL assay , *OPTOFLUIDICS , *POLYMERIZATION , *SILICA , *BIOLOGICAL reagents - Abstract
Shape-encoded silica microparticles for use in multiplexed bioassays were fabricated by using optofluidic maskless lithography (OFML) and tetraethylorthosilicate (TEOS) polymerization. These encoded silica microparticles exhibit excellent bioconjugation properties and negligible non-specific analyte adsorption. Encoded silica microparticles could be useful in a wide variety of applications, including DNA- and protein-based diagnostics. [ABSTRACT FROM AUTHOR]
- Published
- 2015
- Full Text
- View/download PDF
50. Asymmetric Aneuploidy in Mesenchymal Stromal Cells Detected by In Situ Karyotyping and Fluorescence In Situ Hybridization: Suggestions for Reference Values for Stem Cells.
- Author
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Kim, Seon Young, Im, Kyongok, Park, Si Nae, Kwon, Jiseok, Kim, Jung-Ah, Choi, Qute, Hwang, Sang Mee, Han, Sung-Hee, Kwon, Sunghoon, Oh, Il-Hoan, and Lee, Dong Soon
- Subjects
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CHROMOSOME abnormalities , *MESENCHYMAL stem cells , *TISSUE engineering , *FLUORESCENCE in situ hybridization , *CYTOGENETICS , *DIAGNOSIS , *THERAPEUTICS - Abstract
Cytogenetic testing is important to ensure patient safety before therapeutic application of mesenchymal stromal cells (MSCs). However, the standardized methods and criteria for the screening of chromosomal abnormalities of MSCs have not yet been determined. We investigated the frequency of cytogenetic aberrations in MSCs using G-banding and fluorescence in situ hybridization (FISH) and suggest reference values for aneuploidy in MSCs. Cytogenetic analysis was performed on 103 consecutive cultures from 68 MSCs (25 adipose-origin, 20 bone marrow-origin, 18 cord blood-origin, and 5 neural stem cells; 8 from adipose tissue of patients with breast cancer and 60 from healthy donors). We compared the MSC aneuploidy patterns with those of hematological malignancies and benign hematological diseases. Interphase FISH showed variable aneuploid clone proportions (1%-20%) in 68 MSCs. The aneuploidy patterns were asymmetric, and aneuploidy of chromosomes 16, 17, 18, and X occurred most frequently. Clones with polysomy were significantly more abundant than those with monosomy. The cutoff value of maximum polysomy rates (upper 95th percentile value) was 13.0%. By G-banding, 5 of the 61 MSCs presented clonal chromosomal aberrations. Aneuploidy was asymmetric in the malignant hematological diseases, while it was symmetric in the benign hematological diseases. We suggest an aneuploidy cutoff value of 13%, and FISH for aneuploidy of chromosomes 16, 17, 18, and X would be informative to evaluate the genetic stability of MSCs. Although it is unclear whether the aneuploid clones might represent the senescent cell population or transformed cells, more attention should be focused on the safety of MSCs, and G-banding combined with FISH should be performed. [ABSTRACT FROM AUTHOR]
- Published
- 2015
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