520 results on '"Sang, Yong"'
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2. Scattering Properties of MoS2 Edges and Folds Using Darkfield Hyperspectral Microscopy.
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Bong, Sungmin, Hwang, Seongjoo, and Ju, Sang-Yong
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- 2024
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3. Optimal Design Study of Metal-as-Insulation HTS Synchronous Motor With Multiple Operating Points for EVs Based on Many-Objective Optimization
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Jung, Seok-Won, Yoon, Jonghoon, Kim, Hyung-Woo, Hahn, Seungyong, and Jung, Sang-Yong
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This paper presents an optimal design study of a high temperature superconducting (HTS) synchronous motor (HTS-SM) with metal-as-insulation (MI), taking into account multiple operating points relevant to electric vehicles (EVs). To mitigate the charging delay drawback of the no-insulation (NI) technique while retaining its self-quench-protection capability, a stainless steel MI technique is incorporated within the rotor field winding of a partial HTS-SM. Additionally, an optimal design process is proposed that considers various operating points dictated by driving profiles of EVs. The optimization process employs a recent constrained many-objective optimization algorithm (CMaO) to simultaneously handle three or more objectives with constraints. We applied the proposed process to optimize the design of partial HTS-SMs with two distinct MI thicknesses, resulting in Pareto-optimal solutions that prioritize high specific power, minimal HTS tape consumption, and high efficiency across the designated operating points. During the optimization, the finite element method was employed to accurately evaluate the motor's performance characteristics. Finally, we conducted a comprehensive analysis of the Pareto-optimal designs obtained through the optimization process.
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- 2024
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4. Real-Time Observation for MoS2Growth Kinetics and Mechanism Promoted by the Na Droplet
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Oh, Jehyun, Park, Minsuk, Kang, Yoonbeen, and Ju, Sang-Yong
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While the molten salt-catalyzed chemical vapor deposition (CVD) technique is recognized for its effectiveness in producing large-area transition metal chalcogenides, understanding their growth mechanisms involving alkali metals remains a challenge. Here, we investigate the kinetics and mechanism of sodium-catalyzed molybdenum disulfide (MoS2) growth and etching through image analysis conducted using an integrated CVD microscope. Sodium droplets, agglomerated via the thermal decomposition of the sodium cholate dispersant, catalyze the precipitation of supersaturated MoS2laminates and induce growth despite fragmentation during this process. Triangular MoS2crystals display a distinct self-exhausting exponential behavior and slow growth of thermodynamically favorable crystallographic faces, exhibiting a sulfur-dominant pressure. The growth and etching processes are facilitated by the scooting of sodium droplets along grain edges, displaying comparable rates. Leveraging these kinetics makes it possible to engineer atypical MoS2shapes. This combined microscope not only enhances the understanding of growth mechanisms but also contributes to the facile development of next-generation nanomaterials.
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- 2024
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5. Stoichiometric Engineering of Ag2S Nanocrystals to Realize High Performance for Organic–Inorganic Hybrid Photodiodes.
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Sim, Kyu Min, Kwon, Jisu, Ma, Jinhyuk, Pyo, Won Jun, Kim, Dowan, Sung, Yunmo, Nam, Sang Yong, Joo, Taiha, Kim, Sungjee, and Chung, Dae Sung
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- 2024
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6. Distal Radial Access for Coronary Procedures in a Large Prospective Multicenter Registry: The KODRA Trial.
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Lee, Jun-Won, Kim, Yongcheol, Lee, Bong-Ki, Yoo, Sang-Yong, Lee, Sang Yeub, Kim, Chan Joon, Jin, Han-Young, Park, Jin Sup, Heo, Jung Ho, Kim, Do Hoi, Lee, Jin Bae, Kim, Dong-Kie, Bae, Jun Ho, Lee, Sung-Yun, and Lee, Seung-Hwan
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Distal radial access (DRA) as an alternative access route lacks evidence, despite its recent reputation. The aim of this study was to evaluate the safety and feasibility of DRA on the basis of daily practice. The KODRA (Korean Prospective Registry for Evaluating the Safety and Efficacy of Distal Radial Approach) trial was a prospective multicenter registry conducted at 14 hospitals between September 2019 and September 2021. The primary endpoints were the success rates of coronary angiography (CAG) and percutaneous coronary intervention (PCI). The secondary endpoints included successful distal radial artery puncture, access-site crossover, access site–related complications, bleeding events, and predictors of puncture failure. A total of 4,977 among 5,712 screened patients were recruited after the exclusion of 735 patients. The primary endpoints, the success rates of CAG and PCI via DRA, were 100% and 98.8%, respectively, among successful punctures of the distal radial artery (94.4%). Access-site crossover occurred in 333 patients (6.7%). The rates of distal radial artery occlusion and radial artery occlusion by palpation were 0.8% (36 of 4,340) and 0.8% (33 of 4,340) at 1-month follow-up. DRA-related bleeding events were observed in 3.3% of patients, without serious hematoma. Multilevel logistic regression analysis identified weak pulse (OR: 9.994; 95% CI: 7.252-13.774) and DRA experience <100 cases (OR: 2.187; 95% CI: 1.383-3.456) as predictors of puncture failure. In this large-scale prospective multicenter registry, DRA demonstrated high success rates of CAG and PCI, with a high rate of puncture success but low rates of distal radial artery occlusion, radial artery occlusion, bleeding events, and procedure-related complications. Weak pulse and DRA experience <100 cases were predictors of puncture failure. (Korean Prospective Registry for Evaluating the Safety and Efficacy of Distal Radial Approach [KODRA]; NCT04080700) [Display omitted] [ABSTRACT FROM AUTHOR]
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- 2024
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7. Choquet integral-based product satisfaction inference in consideration of subjective decision-making tendencies
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Kwon, Il-Kyoung and Lee, Sang-Yong
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As the Social Commerce market continues to expand, the number of consumers desiring to buy quality products through the Internet increases. The number of products in similar categories, however, is so large that it is difficult for a consumer to choose a product based on price and discount rates. In addition, it is difficult to recommend certain products according to the subjective tendencies of individual buyers. Thus, this study suggests a product satisfaction inference method reflecting the users preferences based on such variables as price, discount rate, number of buyers, and purchase satisfaction, which are most influential in choosing and purchasing goods. To this end, the level of product satisfaction was assessed by determining the Fuzzy Membership Function for each condition of decision-making and Fuzzy Logic-based FIS. To evaluate the level of product satisfaction in reflection of users subjective tendencies, with the disadvantages of FIS excluded, subjective decision-making tools Choquet Integral method and AHP were suggested.
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- 2024
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8. LAYERED DOUBLE HYDROXIDE-BASED MRI/CT DUAL MODAL CONTRASTING AGENT WITH HOMOGENEOUS PARTICLE SIZE
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Jung, Sang-Yong, Park, Jin Kuen, and Oh, Jae-Min
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The development of nanoparticles incorporating Gd3+has attracted interest in the field of contrasting nanomedicine for magnetic resonance (MR) and computed tomography (CT). In order to achieve an effective contrasting performance, the amount and stability of Gd incorporated as well as particle-size control of the nanoparticles should be considered simultaneously. In the current study, Gd-diethylenetriaminepentaacetate(Gd-DTPA) was incorporated into layered double hydroxide (LDH) to meet the physicochemical properties required for MR-CT dual contrasting nanomedicine. Strategically, the particle size and nanometer incorporation of Gd-DTPA into LDH (GL-R hybrid) were controlled homogeneously using the reverse micelle method. X-ray diffraction showed that the hybrid obtained possessed a hydrotalcite phase. Dynamic light scattering and electron microscopic analyses showed that the hybrid had a controlled size of <200 nm with significant homogeneity. Fast Fourier-transform of transmission electron microscopy confirmed that the platelets of the GL-R hybrids were oriented randomly to form inter-particle space, enabling the Gd-DTPA moiety to be encapsulated stably. The encapsulation efficiency of Gd-DTPA was 20.8%, which was sufficiently high compared with other Gd-DTPA-incorporatedLDH. According to X-ray photoelectron spectroscopy and Fourier-transform infrared spectroscopy, Gd-DTPA incorporated in the hybrid preserved its structure intact. Its potential as a dual modal contrast agent was demonstrated by measuring the concentration-dependent Hounsfield unit and magnetic resonance relaxivity, which were determined to be 230 at 2 mg/mL and 5.8 in the range ~0.2–1 mM-Gd, respectively.
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- 2024
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9. Design Method of IPMSM Using Multi-objective Optimization Considering Mechanical Stress for High-Speed Electric Vehicles
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Ji, Tae-Hyuk, Kim, Chan-Ho, Jung, Seok-Won, and Jung, Sang-Yong
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This paper proposes an optimal design method of interior permanent magnet synchronous motors based on multi-objective optimization including the mechanical stress for high-speed electric vehicles (EVs). Optimization design of motors for high-speed EVs is a time–cost challenge, requiring the resolution of multi-objective problems such as various performance targets and constraints across multi-physics. To improve the optimization efficiency, we introduce a sequential multi-physics handling method that consists of a two-step optimal process. In each step, specific design variables are selected based on their predominant influence on electromagnetic and mechanical characteristics, respectively. The chosen variables are then applied to each problem to optimize the objective functions with constraints. In the first step, optimization is carried out for the electromagnetic problems using comprehensive design variables, which are relatively coarse for addressing mechanical problems. In the second step, particularly relying on specific variables that mainly influence mechanical stress, optimization considering mechanical stress is performed with the final model of the first step. As a result, dividing the design process into two steps, complex high-dimensional problems are treated as low-dimensional problems that apply appropriate design variables for each physics problem. To simultaneously optimize and precisely evaluate motor characteristics, a multi-objective optimization, and the finite element method are employed in the design process. Finally, we verified the proposed method by designing an IPMSM for high-speed EVs that satisfies all requirements.
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- 2024
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10. Coupled Problem Study with Structural Analysis Considering Barrier Filling of PMa-SynRM for Railway Vehicle
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Kang, Seung-Gu, Kang, Do Hyun, Kim, Hyung-Woo, Jung, Seok-Won, Lee, Jin Hwan, and Jung, Sang-Yong
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This paper investigates the structural-electromagnetic coupled problem of a permanent magnet assisted-synchronous reluctance motor (PMa-SynRM) for railway vehicles considering the barrier filling. The PMa-SynRM is suitable as a traction motor for railway vehicles but is vulnerable to the structural stability of the rotor under centrifugal force. Therefore, the structural characteristics of the PMa-SynRM should be considered, and the structural influences on the electromagnetic performance are also important based on the stress-dependent properties of the electrical steel core. To improve the structural stability, the concept of barrier filling is proposed, which involves inserting a substance into the magnetic flux barrier region of the PMa-SynRM and balancing the loads in the rotor core. The structural analysis results with the barrier fillings are compared for a wide range of their physical properties. We input stress and strain data by element into the rotor electrical steel core of the electromagnetic model, which consists of the identical mesh as the rotor structural analysis results and set conditions to reflect the stress-dependent B-H and iron loss data to analyze the electromagnetic performance including coupled effects. Finally, the best filling substance is derived and applied based on the previous structural analysis results, clarifying the improvement in the structural and electromagnetic characteristics.
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- 2024
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11. Association between urinary arsenic concentration and genetic polymorphisms in Korean adults
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Lee, Seul-Gi, Eom, Sang-Yong, Lim, Ji-Ae, Choi, Byung-Sun, Kwon, Ho-Jang, Hong, Young-Seoub, Kim, Yong-Dae, Kim, Heon, and Park, Jung-Duck
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Arsenic (As) is a human carcinogen widely distributed in the environment. This study evaluated the association between the urinary As concentration and single nucleotide polymorphisms (SNPs) in Korean adults to determine the genetic factors related to As concentration. The study included 496 participants for the genome-wide association study (GWAS) and 1483 participants for the candidate gene approach study. Participants were 19 years and older. The concentrations of total As (Tot As) and total As metabolites (Tmet As, the sum of inorganic As and their metabolites; arsenite, arsenate, monomethylarsonic, and dimethylarsinic acid) in the urine were analyzed. The GWAS identified four SNPs (rs1432523, rs3776006, rs11171747, and rs807573) associated with urinary Tot As and four SNPs (rs117605537, rs3776006, rs11171747, and rs148103384) significantly associated with urinary Tmet As concentration (P< 1 × 10–4). The candidate gene study identified two SNPs (PRDX2rs10427027 and GLRXrs3822751) in genes related to the reduction reaction associated with urinary Tot As and Tmet As. This study suggests that genetic factors may play a role in regulating As metabolism in the human body, affecting both exposure levels and its potential health risks in the general Korean population, even at low exposure levels.
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- 2024
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12. Spatiotemporally Controllable Electrical Stimulator via Independent Photobending and Upconversion Photoluminescence Using Two Different Wavelengths of Near-Infrared/Visible Light as Dual Stimuli.
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Lee, Jiyeon, Kim, Dongjun, Park, Minsuk, Ryu, Jaehyeok, Park, Hyunbin, Kim, Taehee, Kim, Dongho, Ju, Sang-Yong, and Kim, Jiwon
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- 2023
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13. iPS-cell-derived microglia promote brain organoid maturation via cholesterol transfer
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Park, Dong Shin, Kozaki, Tatsuya, Tiwari, Satish Kumar, Moreira, Marco, Khalilnezhad, Ahad, Torta, Federico, Olivié, Nicolas, Thiam, Chung Hwee, Liani, Oniko, Silvin, Aymeric, Phoo, Wint Wint, Gao, Liang, Triebl, Alexander, Tham, Wai Kin, Gonçalves, Leticia, Kong, Wan Ting, Raman, Sethi, Zhang, Xiao Meng, Dunsmore, Garett, Dutertre, Charles Antoine, Lee, Salanne, Ong, Jia Min, Balachander, Akhila, Khalilnezhad, Shabnam, Lum, Josephine, Duan, Kaibo, Lim, Ze Ming, Tan, Leonard, Low, Ivy, Utami, Kagistia Hana, Yeo, Xin Yi, Di Tommaso, Sylvaine, Dupuy, Jean-William, Varga, Balazs, Karadottir, Ragnhildur Thora, Madathummal, Mufeeda Changaramvally, Bonne, Isabelle, Malleret, Benoit, Binte, Zainab Yasin, Wei Da, Ngan, Tan, Yingrou, Wong, Wei Jie, Zhang, Jinqiu, Chen, Jinmiao, Sobota, Radoslaw M., Howland, Shanshan W., Ng, Lai Guan, Saltel, Frédéric, Castel, David, Grill, Jacques, Minard, Veronique, Albani, Salvatore, Chan, Jerry K. Y., Thion, Morgane Sonia, Jung, Sang Yong, Wenk, Markus R., Pouladi, Mahmoud A., Pasqualini, Claudia, Angeli, Veronique, Cexus, Olivier N. F., and Ginhoux, Florent
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Microglia are specialized brain-resident macrophages that arise from primitive macrophages colonizing the embryonic brain1. Microglia contribute to multiple aspects of brain development, but their precise roles in the early human brain remain poorly understood owing to limited access to relevant tissues2–6. The generation of brain organoids from human induced pluripotent stem cells recapitulates some key features of human embryonic brain development7–10. However, current approaches do not incorporate microglia or address their role in organoid maturation11–21. Here we generated microglia-sufficient brain organoids by coculturing brain organoids with primitive-like macrophages generated from the same human induced pluripotent stem cells (iMac)22. In organoid cocultures, iMac differentiated into cells with microglia-like phenotypes and functions (iMicro) and modulated neuronal progenitor cell (NPC) differentiation, limiting NPC proliferation and promoting axonogenesis. Mechanistically, iMicro contained high levels of PLIN2+lipid droplets that exported cholesterol and its esters, which were taken up by NPCs in the organoids. We also detected PLIN2+lipid droplet-loaded microglia in mouse and human embryonic brains. Overall, our approach substantially advances current human brain organoid approaches by incorporating microglial cells, as illustrated by the discovery of a key pathway of lipid-mediated crosstalk between microglia and NPCs that leads to improved neurogenesis.
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- 2023
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14. Mouse genome rewriting and tailoring of three important disease loci
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Zhang, Weimin, Golynker, Ilona, Brosh, Ran, Fajardo, Alvaro, Zhu, Yinan, Wudzinska, Aleksandra M., Ordoñez, Raquel, Ribeiro-dos-Santos, André M., Carrau, Lucia, Damani-Yokota, Payal, Yeung, Stephen T., Khairallah, Camille, Vela Gartner, Antonio, Chalhoub, Noor, Huang, Emily, Ashe, Hannah J., Khanna, Kamal M., Maurano, Matthew T., Kim, Sang Yong, tenOever, Benjamin R., and Boeke, Jef D.
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Genetically engineered mouse models (GEMMs) help us to understand human pathologies and develop new therapies, yet faithfully recapitulating human diseases in mice is challenging. Advances in genomics have highlighted the importance of non-coding regulatory genome sequences, which control spatiotemporal gene expression patterns and splicing in many human diseases1,2. Including regulatory extensive genomic regions, which requires large-scale genome engineering, should enhance the quality of disease modelling. Existing methods set limits on the size and efficiency of DNA delivery, hampering the routine creation of highly informative models that we call genomically rewritten and tailored GEMMs (GREAT-GEMMs). Here we describe ‘mammalian switching antibiotic resistance markers progressively for integration’ (mSwAP-In), a method for efficient genome rewriting in mouse embryonic stem cells. We demonstrate the use of mSwAP-In for iterative genome rewriting of up to 115 kb of a tailored Trp53locus, as well as for humanization of mice using 116 kb and 180 kb human ACE2loci. The ACE2model recapitulated human ACE2expression patterns and splicing, and notably, presented milder symptoms when challenged with SARS-CoV-2 compared with the existing K18-hACE2model, thus representing a more human-like model of infection. Finally, we demonstrated serial genome writing by humanizing mouse Tmprss2biallelically in the ACE2GREAT-GEMM, highlighting the versatility of mSwAP-In in genome writing.
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- 2023
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15. Reactions of 2,4‐dinitrophenyl 5‐substituted‐2‐thiophenecarboxylate promoted by 4‐ZC6H4O−/4‐ZC6H4OHin 20 mol% DMSO(aq). Effects of leaving group and nucleophile on the acyl transfer reactions
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Pyun, Sang Yong, Paik, Kyu Cheol, Han, Man So, Hong, Seung Taek, and Cho, Bong Rae
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The kinetics of nucleophilic substitution reactions involving 2,4‐dinitrophenyl 5‐substituted‐2‐thiophenecarboxylate were studied kinetically with 4‐Z‐C6H4O−/4‐Z‐C6H4OH, which facilitated the reactions, in 20 mol% DMSO(aq). The reactions followed second‐order kinetics and exhibited βacyl= −2.34 to −2.92, ρ(Y) = 2.71–3.39, βnuc= 0.74–0.83, and |βlg| = 0.40–0.57. Based on the interpretation of the results, we have concluded that the reaction follows an addition–elimination mechanism in which the first step is the rate‐determining step (rds). The transition state structures for the 4‐ZC6H4O−‐promoted reactions remained nearly the same with a change in the leaving group from 4‐nitrophenoxide to 2,4‐dinitrophenoxide. The mechanism of the 4‐ZC6H4O−‐promoted reaction was similar to that of R2NH‐promoted reactions, except that the former proceeded with the 1st step being the rds and the latter proceeded with a change in the rds from the second to the first step with a stronger nucleophile.
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- 2023
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16. Spatiotemporally Controllable Electrical Stimulator via Independent Photobending and Upconversion Photoluminescence Using Two Different Wavelengths of Near-Infrared/Visible Light as Dual Stimuli
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Lee, Jiyeon, Kim, Dongjun, Park, Minsuk, Ryu, Jaehyeok, Park, Hyunbin, Kim, Taehee, Kim, Dongho, Ju, Sang-Yong, and Kim, Jiwon
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Multistimuli responsive materials are advantageous in that they can enhance the desired response or bypass unwanted reactions. Light is one of the most attractive stimuli since it allows remote spatiotemporal control and multiplexing of properties (e.g., wavelength, intensity, irradiation time, pulsed/continuous wave) for application on multiphotoresponsive materials. However, the operating wavelength for such photoresponsive systems often includes an ultraviolet (UV) range that limits its use in the biomedical field. Herein, we investigate near-infrared (NIR)/visible (Vis) light-responsive nanocomposite films composed of rare earth element (i.e., Yb, Er)-doped NaYF4nanoparticles (NPs) embedded in azobenzene-incorporated poly(dimethylsiloxane) (AzoPDMS), silk fibroin, and silver nanowire (AgNW) layers. Photobending (PB) of the nanocomposite film is induced by a Vis light of 400–700 nm, while upconversion photoluminescence (UCPL) of embedded NPs is activated by an NIR light of 980 nm. The excitation wavelength of photoluminescence (PL) is shifted to the NIR (λ = 980 nm) range via photon upconversion in rare earth element-doped NPs. Independent operation of PB and UCPL enables both on-demand electrical switching and real-time location monitoring for spatiotemporally controlled electrical pulse stimulation. As a result, the dual-photoresponsive nanocomposite film can be utilized as a remotely controllable electrical stimulator and location indicator via different wavelengths of light.
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- 2023
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17. Performance Enhancement Using Robust Sliding Mode Approach-Based Current Control for PMVG-WECS
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Antonysamy, Ruban Periyanayagam, Lee, Seong Ryong, Jung, Sang Yong, and Joo, Young Hoon
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Conventional current control (CC) has been utilized to control the converter's voltage in a wind energy conversion system (WECS) due to its ease of implementation. However, mismatched machine parameters and slow-dynamic response can reduce total system performance. To deal with this issue, this study proposes a robust sliding mode approach-based CC scheme for machine side converter and grid side converter of a grid-connected permanent magnet vernier generator (PMVG). To do this, a direct-drive grid-connected PMVG-based WECS is firstly modeled using a back-to-back converters. Currently, the voltage control references to the converters have been designed using a proportional-integral (PI)-type sliding surface with a modified version of the improved reaching law-based on sliding mode control (SMC) theory. As a result, smooth
-axes voltage references are obtained, which leads to a better steady-state and transient performance from the overall system. Further, the reduced chattering achieves an improved total harmonic distortion reduction in grid current, significantly enhancing the power quality. Then, the Lyapunov stability is derived to verify the reachability condition for the proposed scheme. Finally, the proposed controller is compared with PI and existing SMC methods through simulation and experimental setup of a 5-kW PMVG system.$dq$ - Published
- 2023
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18. Atomic-Scale Andreev Probe of Unconventional Superconductivity.
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Ko, Wonhee, Song, Sang Yong, Yan, Jiaqiang, Lado, Jose L., and Maksymovych, Petro
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- 2023
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19. Facile Direct Printing of DPP-Based Polymers for Organic Field-Effect Transistors and Logic Gates.
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Hong, Jisu, Kim, Jingwan, Li, Zhijun, Cong, Chenhao, Rand, Barry P., Nam, Sang Yong, Kim, Se Hyun, and Kim, Yun-Hi
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- 2023
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20. Amorphous Fluorinated Acrylate Polymer Dielectrics for Flexible Transistors and Logic Gates with High Operational Stability.
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Ye, Heqing, Ryu, Ka Yeon, Kwon, Hyeok-jin, Lee, Hyunji, Wang, Rixuan, Hong, Jisu, Choi, Hyun Ho, Nam, Sang Yong, Lee, Jihoon, Kong, Hoyoul, and Kim, Se Hyun
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- 2023
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21. Nematically Templated Vortex Lattices in Superconducting FeSe.
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Song, Sang Yong, Hua, Chengyun, Bell, Luke, Ko, Wonhee, Fangohr, Hans, Yan, Jiaqiang, Halász, Gábor B., Dumitrescu, Eugene F., Lawrie, Benjamin J., and Maksymovych, Petro
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- 2023
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22. Atomic-Scale Andreev Probe of Unconventional Superconductivity
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Ko, Wonhee, Song, Sang Yong, Yan, Jiaqiang, Lado, Jose L., and Maksymovych, Petro
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Recent emergence of low-dimensional unconventional superconductors and their exotic interface properties calls for new approaches to probe the pairing symmetry, a fundamental and frequently elusive property of the superconducting condensate. Here, we introduce the unique capability of tunneling Andreev reflection (TAR) to probe unconventional pairing symmetry, utilizing the sensitivity of this technique to specific Andreev reflections. Specifically, suppression of the lowest-order Andreev reflection due to quantum interference but emergence of the higher-order Andreev processes provides direct evidence of the sign-changing order parameter in the paradigmatic FeSe superconductor. TAR spectroscopy also reveals two superconducting gaps, points to a possibility of a nodal gap structure, and directly confirms that superconductivity is locally suppressed along the nematic twin boundary, with preferential and near-complete suppression of the larger energy gap. Our findings therefore enable new, atomic-scale insight into microscopic, inhomogeneous, and interfacial properties of emerging quantum materials.
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- 2023
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23. Reply to “Small airway dysfunction is common even in mild asthma, suggests increased exacerbation risk”
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Hahn, Youn-Soo and Eom, Sang-Yong
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- 2024
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24. Impact of Clinical Association Between Gout and Dementia: A Nationwide Population‐BasedCohort Study in Korea
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Kim, Ji Hyoun, Yim, Dong‐Hyuk, Choi, In Ah, Lee, Jeonghwan, Park, Hyemi, and Eom, Sang‐Yong
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Hyperuricemia might have neuroprotective or neurodegenerative effects on dementia via oxidative stress or inflammatory response regulation. Few studies have explored the association of hyperuricemia or gout with dementia. This retrospective cohort study aimed to investigate the association between gout and dementia in Korea. Altogether, 5,052 gout patients and 25,260 age‐ and sex‐matched controls were selected from the National Health Insurance Service (NHIS)–National Sample Cohort database. The incidence and risk of dementia were evaluated by reviewing the NHIS record. We also performed a subgroup analysis according to age group (age <65 or ≥65 years) using the standard age of 65 years for elderly and nonelderly groups and sex. During follow‐up, 81 and 558 participants in the gout and control cohorts developed dementia, respectively. The mean follow‐up duration was 4.38 years in gout patients and 4.94 years in controls. Gout patients had a hazard ratio (HR) of 0.79 for overall dementia (95% confidence interval [95% CI] 0.62–1.00) and significantly lower Alzheimer's disease risk (HR 0.73 [95% CI 0.54–0.98]) after adjusting for age, sex, household income, and comorbidities. In subgroup analysis stratified by age and sex, the inverse association between gout and the risk of overall dementia (HR 0.71 [95% CI 0.52–0.97]) and Alzheimer's disease (HR 0.67 [95% CI 0.46–0.97]) were observed in the elderly male group. On the other hand, age‐ and sex‐adjusted analysis showed that the HR for vascular dementia of gout patients was 2.31 (95% CI 1.02–5.25) in the nonelderly male group. Gout decreased the risk of incident Alzheimer's disease–type dementia, especially in elderly patients. The association between gout and dementia risk may differ according to age and disease duration.
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- 2023
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25. Operation Characteristics of Superconducting DC Circuit Breaker for Reliability Assessment in a Transient State of MMC VSC-HVDC
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Park, Sang-Yong and Choi, Hyo-Sang
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Globally, the supply and demand of DC are increasing due to climate change and the technological development of power semiconductors. In this trend, the International Large Electric Systems Council tried to solve the above problems by researching HVDC systems. However, the application range of HVDC systems continues to widen. Accordingly, the reliability of dangerous power transmission and distribution through the transient state of the DC system is becoming a new problem. Since DC has no frequency compared to AC, the growth rate of the fault current is very fast, and there is no cutting-off zero point. Therefore, a technology capable of stably cutting off the DC fault current was required. We proposed a hybrid superconducting DC circuit breaker. It quenches the superconducting current limiter and creates an artificial zero point of the mechanical DC circuit breaker. Therefore, DC fault current without frequency can be cut off stably and effectively. To examine the operating characteristics of the proposed superconducting DC circuit breaker, we applied the circuit breaker to the MMC VSC-HVDC system model. In this paper, the current limiting rate of the initial fault current of the superconducting DC circuit breaker, the artificial breaking zero point, and the breaking operation time were analyzed. As a result, it was confirmed that the superconducting current-limiting module limited the initial current-limiting current to about 58.27%. In addition, it was confirmed that the mechanical DC circuit breaker made an artificial cutting-off zero point and performed a fast-breaking operation of about 80% or more.
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- 2023
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26. Nematically Templated Vortex Lattices in Superconducting FeSe
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Song, Sang Yong, Hua, Chengyun, Bell, Luke, Ko, Wonhee, Fangohr, Hans, Yan, Jiaqiang, Halász, Gábor B., Dumitrescu, Eugene F., Lawrie, Benjamin J., and Maksymovych, Petro
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New pathways to controlling the morphology of superconducting vortex lattices─and their subsequent dynamics─are required to guide and scale vortex world-lines into a computing platform. We have found that the nematic twin boundaries align superconducting vortices in the adjacent terraces due to the incommensurate potential between vortices surrounding twin boundaries and those trapped within them. With the varying density and morphology of twin boundaries, the vortex lattice assumes several distinct structural phases, including square, regular, and irregular one-dimensional lattices. Through concomitant analysis of vortex lattice models, we have inferred the characteristic energetics of the twin boundary potential and furthermore predicted the existence of geometric size effects as a function of increasing confinement by the twin boundaries. These findings extend the ideas of directed control over vortex lattices to intrinsic topological defects and their self-organized networks, which have direct implications for the future design and control of strain-based topological quantum computing architectures.
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- 2023
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27. Effect of Cross-Linking and Surface Treatment on the Functional Properties of Electrospun Polybenzimidazole Separators for Lithium Metal Batteries.
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Jung, Ji Hye, Vijayakumar, Vijayalekshmi, Haridas, Anupriya K., Ahn, Jou-Hyeon, and Nam, Sang Yong
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- 2022
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28. Hierarchical van der Waals Heterostructure Strategy to Form Stable Transition Metal Dichalcogenide Dispersions.
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Park, Junmo, Bong, Sungmin, Park, Jaehyun, Lee, Eunji, and Ju, Sang-Yong
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- 2022
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29. Operation Characteristics of DC Circuit Breaker Using Arc Induction Technique According to the Magnetism of the Superconducting Magnet
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Park, Sang-Yong and Choi, Hyo-Sang
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With the development and advancement of renewable energy sources, the interest in DC power distribution systems is increasing, highlighting the importance of research on the fault current cutoff technology for DC power and grid protection. A stable cutoff technology must be developed to secure the stability and high reliability of the DC system in the future. The most important factor in the cutoff technology is how to effectively extinguish the arc that occurs when the fault system is interrupted. Therefore, further research on arc extinguishes technology for DC distribution systems is inevitable. In this paper, a new magnetic arc induction technique is proposed. The magnetic arc induction technique blows the arc between the break contacts through the magnet toward the induction needle. The induction needle absorbs the arc before sending it to the ground wire for extinction purposes. However, the mechanical DC circuit breakers have a limited opening speed. We want to overcome this limitation with superconducting magnets. The previous simulation results confirm the feasibility of the magnetic arc induction technique, and this was attempted to be proven in this study through experimentation. As a result, it was confirmed that the arc extinction time was reduced depending on the presence or absence of a magnet. It may be the basis for developing the distribution system mechanical breakers.
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- 2023
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30. CFD analysis of direct-operated poppet relief valve under different parameters and its structure optimisation
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Sang, Yong, Liu, Pengkun, and Wang, Xudong
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This paper investigates the dynamic characteristics of the direct-operated poppet relief valve (DOPRV) with different parameters and improves its dynamic characteristics by modifying the core. First, a simplified schematic of the valve is introduced; mesh elements, SST k~ωturbulence model and corresponding time step size are selected by comparing the simulation results. Then, simulation is conducted under different nominal diameters, and a suitable range of diameter is determined. Further, an improved structure of the DOPRV is introduced, and the dynamic characteristics of the DOPRV under improved structure are stimulated under different annular clearance, spring stiffness, and pressure jump. The simulation results show that adding annular clearance can largely enhance the dynamic performance of DOPRV and the optimal annular clearance for the 20 mm diameter DOPRV in this paper is 0.2 mm.
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- 2023
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31. Back Yoke Design of Axial Flux Permanent Magnet Motors with Fractional-Slot Concentrated Winding for High Power Density
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Ji, Tae-Hyuk, Kim, Chan-Ho, Yoon, Han-Joon, Kim, Nam-Ho, Jung, Seok-Won, Kim, Yong-Jae, and Jung, Sang-Yong
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Many researchers have investigated axial flux permanent magnet motors (AFPMMs) with fractional-slot concentrated winding (FSCW) to achieve high power density. For an AFPMM with an FSCW, the path of the magnetic flux is determined based on the winding characteristics and position of the permanent magnet. Therefore, magnetic saturated and non-saturated parts of cores are regularly present. The back yoke of the cores is generally designed only in terms of width because it can control the magnetic saturation. However, designing the back yoke only by width has a limitation in considering the non-saturated part of the cores, which can cause a decrease in power density. Therefore, by modifying the topology of the back yoke to consider the non-saturated part of the cores, the power density can be improved. In this study, we designed the back yoke of a single-sided AFPMM with an FSCW using design variables to increase the power density. Subsequently, by applying the same process, we designed the shape of the back yokes of double-sided type AFPMMs to improve the power density.
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- 2023
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32. Torque Equation to Predict Torque Harmonic Characteristic of IPMSM According to Winding Arrangement, Number of Phases, and Pole-Slot Combination
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Yoon, Han-Joon, Jun, Sung-Bae, Kim, Nam-Ho, Kim, Yong-Jae, and Jung, Sang-Yong
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This paper presents a novel torque equation to predict the torque harmonic characteristic of an interior permanent-magnet synchronous motor (IPMSM). The procedure for establishing the proposed equation is as follows. First, we classify the origins of torque, phase, and slot harmonics. The harmonics are then analyzed to study the relationship between the harmonic generated in the N and S poles of a magnet. Second, we establish the equation consisting of two terms for phase and slot harmonics. In particular, the phase harmonic part embodies a new concept, namely the number of coil groups per phase wound in the adjacent slots to express the period of the stator magneto-motive force. Based on the analysis results, the proposed equation is applied to an IPMSM to verify whether the equation can consider the three cases: the winding arrangement, slot–pole combination, and number of phases. The equation can aid the initial design focusing on the low torque ripple characteristic.
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- 2023
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33. Clinical outcomes of marginal ulcer bleeding compared with those of peptic ulcer bleeding
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Seo, Jun-young, Noh, Jin Hee, Ahn, Ji Yong, Cho, Sang yong, Oh, Seung-pyo, Cha, Boram, Na, Hee Kyong, Lee, Jeong Hoon, Jung, Kee Wook, Kim, Do Hoon, Choi, Kee Don, Song, Ho June, Lee, Gin Hyug, and Jung, Hwoon-Yong
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Background: Marginal ulcer bleeding (MUB) is a complication that can occur following several types of surgery. However, few studies exist on it. Therefore, this study aimed to compare the clinical outcomes of MUB with those of peptic ulcer bleeding (PUB). Methods: Between January 2013 and December 2017, 5,076 patients underwent emergent esophagogastroduodenoscopy for suspected upper gastrointestinal bleeding. We retrospectively reviewed and analyzed the medical records of MUB and PUB patients and developed a propensity score matching (PSM) method to adjust for between-group differences in baseline characteristics with 1:2 ratios. Sex, age, body mass index (BMI), underlying diseases, and drugs were included as matching factors. Results: A total of 64 and 678 patients were diagnosed with MUB and PUB, respectively, on emergent esophagogastroduodenoscopy, and 62 and 124 patients with MUB and PUB, respectively, were selected after PSM. Rebleeding was significantly higher in patients with MUB than in those with PUB (57.8% vs 9.1%, p< 0.001). Mortality caused by bleeding was higher in patients with MUB than in those with PUB (4.7% vs. 0.4%, p< 0.001). Multivariate analysis revealed that proton pump inhibitor (PPI) administration (odds ratio [OR], 0.14; 95% confidence interval [CI], 0.03–0.56; p= 0.011) after first bleeding was inversely correlated with MUB rebleeding. Large ulcer size (> 1 cm) (OR, 6.69; 95% CI, 1.95–27.94; p= 0.005) and surgery covering pancreas (OR, 3.97; 95% CI, 1.19–15.04) were independent risk factors for MUB rebleeding. Conclusions: MUB showed a severe clinical course than PUB. Therefore, MUB should be managed more cautiously, especially for large ulcers and pancreatic surgery. Prophylactic PPI administration may be helpful in reducing rebleeding in MUB.
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- 2023
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34. Laparoscopic vs Open Distal Gastrectomy for Locally Advanced Gastric Cancer: 5-Year Outcomes of the KLASS-02 Randomized Clinical Trial
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Son, Sang-Yong, Hur, Hoon, Hyung, Woo Jin, Park, Young-Kyu, Lee, Hyuk-Joon, An, Ji Yeong, Kim, Wook, Kim, Hyoung-Il, Kim, Hyung-Ho, Ryu, Seung Wan, Kim, Min-Chan, Kong, Seong-Ho, Cho, Gyu Seok, Kim, Jin-Jo, Park, Do Joong, Ryu, Keun Won, Kim, Young Woo, Kim, Jong Won, Lee, Joo-Ho, Yang, Han-Kwang, and Han, Sang-Uk
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IMPORTANCE: The long-term safety of laparoscopic distal gastrectomy for locally advanced gastric cancer (AGC) remains uncertain given the lack of 5-year follow-up results. OBJECTIVE: To compare the 5-year follow-up results in patients with clinically AGC enrolled in the Korean Laparoendoscopic Gastrointestinal Surgery Study (KLASS)-02 randomized clinical trial who underwent laparoscopic or open distal gastrectomy. DESIGN, SETTING, AND PARTICIPANTS: The KLASS-02, a multicenter randomized clinical trial, showed that laparoscopic surgery was noninferior to open surgery for patients with locally AGC. The present study assessed the 5-year follow-up results, including 5-year overall survival (OS) and relapse-free survival (RFS) rates and long-term complications, in patients enrolled in KLASS-02. From November 21, 2011, to April 29, 2015, patients aged 20 to 80 years diagnosed preoperatively with locally AGC were enrolled. Final follow-up was on June 15, 2021. Data were analyzed June 24 to September 9, 2021. INTERVENTIONS: Patients were treated with R0 resection either by laparoscopic gastrectomy or open gastrectomy as the full analysis set of the KLASS-02 trial. MAIN OUTCOMES AND MEASURES: Five-year OS and RFS rates, recurrence patterns, and long-term surgical complications were evaluated. RESULTS: This study enrolled a total of 1050 patients. A total of 974 patients were treated with R0 resection; 492 (50.5%) in the laparoscopic gastrectomy group (mean [SD] age, 59.8 [11.0] years; 351 men [71.3%]) and 482 (49.5%) in the open gastrectomy group (mean [SD] age, 59.4 [11.5] years; 335 men [69.5%]). In patients who underwent laparoscopic and open distal gastrectomy, the 5-year OS (88.9% vs 88.7%) and RFS (79.5% vs 81.1%) rates did not differ significantly. The most common types of recurrence were peritoneal carcinomatosis (73 of 173 [42.1%]), hematogenous metastases (36 of 173 [20.8%]), and locoregional recurrence (23 of 173 [13.2%]), with no between-group differences in types of recurrence at each cancer stage. The correlation between 3-year RFS and 5-year OS at the individual level was highest in patients with stage III gastric cancer (ρ = 0.720). The late complication rate was significantly lower in the laparoscopic than in the open surgery group (32 of 492 [6.5%] vs 53 of 482 [11.0%]). The most common type of complication in both groups was intestinal obstruction (13 of 492 [2.6%] vs 24 of 482 [5.0%]). CONCLUSIONS AND RELEVANCE: The 5-year outcomes of the KLASS-02 trial support the 3-year results, which is the noninferiority of laparoscopic surgery compared with open gastrectomy for locally AGC. The laparoscopic approach can be recommended in patients with locally AGC to achieve the benefit of low incidence of late complications. TRIAL REGISTRATION: ClinicalTrials.gov Identifier: NCT01456598
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- 2022
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35. Diagnostic and Prognostic Value of Ergonovine Echocardiography for Noninvasive Diagnosis of Coronary Vasospasm.
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Om, Sang Yong, Yoo, Sang-Yong, Cho, Goo-Yeong, Kim, Minsoo, Woo, Yeongmin, Lee, Sahmin, Kim, Dae-Hee, Song, Jong-Min, Kang, Duk-Hyun, Cheong, Sang Sig, Park, Seong-Wook, Park, Seung-Jung, and Song, Jae-Kwan
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This study sought to obtain large-scale evidence supporting the clinical usefulness of ergonovine echocardiography. The role of noninvasive ergonovine provocation testing with echocardiographic monitoring of ventricular wall motion (ergonovine echocardiography) needs to be defined. Clinical data of patients who underwent ergonovine echocardiography in 3 tertiary referral hospitals in South Korea were analyzed. Ergonovine echocardiography was performed in 14,012 patients (mean age 52.8 ± 11.1 years; 6,213 [44.3%] women) after exclusion of significant coronary arterial stenosis by functional (treadmill or perfusion scan, n = 9,824) or anatomic test (invasive or computerized tomographic coronary angiography, n = 4,188). Premature termination developed in 0.4% (n = 51), and a positive result was observed in 2,144 patients (15.3%), with variable frequencies according to the diagnosis (acute coronary syndrome [38.2%], variant angina [31.8%], effort angina [14.9%], aborted sudden cardiac death [17.6%], syncope [9.9%]). There was no mortality or development of myocardial infarction during the test. During median follow-up of 11.4 (interquartile range: 7.2 to 15.8) years, death of any cause and cardiovascular death occurred in 494 and 143 patients, respectively. The 10-year overall (96.7 ± 0.2% vs. 91.5 ± 0.6%; p < 0.0001) and cardiovascular mortality–free (99.2 ± 0.1% vs. 96.7 ± 0.4%; p < 0.0001) survival rates were lower in patients with positive ergonovine echocardiography. Regarding patients with positive test results, the functional test group and the anatomic test group did not show a significant difference in the survival rates. After adjustment of age and male sex, a positive test was an independent risk factor associated with all-cause mortality (hazard ratio: 1.879, 95% confidence interval: 1.548 to 2.280; p < 0.001) and cardiovascular death (hazard ratio: 2.903, 95% confidence interval: 2.061 to 4.089; p < 0.001). Ergonovine echocardiography for coronary vasospasm diagnosis could be safely performed even without angiographic documentation of fixed coronary stenosis depending on the clinical presentation, and provided important prognostic implication. Ergonovine echocardiography can replace the invasive spasm provocation testing, which has been overlooked unfairly. [ABSTRACT FROM AUTHOR]
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- 2020
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36. Development of a molecular marker based on chloroplast gene for specific identification of Korean Hibiscus (Hibiscus syriacus 'Simbaek').
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Wang, Rongbo, Park, Sang Yong, Park, Sul Woong, Puja, Aditi Mitra, and Kim, Yeon-Ju
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- 2021
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37. Efficacy and Safety of a New Sustained-release Pregabalin Formulation Compared With Immediate-release Pregabalin in Patients With Peripheral Neuropathic Pain
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Han, Kyung Ah, Lee, Yong-Ho, Son, Hyun-Shik, Song, Ki-Ho, Kim, Sang Yong, Chung, Choon Hee, Jang, Hak Chul, Lee, Kwan-Woo, Cha, Bong Yun, Song, Kee-Ho, Ko, Young Kwon, Lee, Pyung-Bok, Kim, Beom Joon, Kim, Sohee, An, Taewon, and Kim, Yong-Chul
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- 2022
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38. Development and characterization of engineering plastic diaphragm for alkaline water electrolysis
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Im, Kwang Seop, Lee, Tae Kyung, Kim, Do Hyeong, Kim, Jae Yoon, Park, Jun Ho, Lee, Dong Jun, Yamaguchi, Takeo, and Nam, Sang Yong
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Research on carbon dioxide free energy sources is increasing due to climate change, with green hydrogen gaining significant attention for its eco-friendly production process. This study focused on creating a diaphragm for alkaline water electrolysis using the TIPS method, utilizing the engineering thermoplastics PEEK and PPS for their excellent mechanical properties and heat resistance. DPK was employed as a diluent, and the phase diagram was established by measuring the crystallization temperature and cloud point based on polymer content. The morphology of the diaphragm, both surface and cross-section, was observed using an SEM, while tensile strength, alkaline stability, and permeability tests assessed its suitability for alkaline electrolysis conditions. The diaphragm with a polymer content of 20 wt% demonstrated a mechanical strength of 31.9 MPa, making it viable for operational use in alkaline electrolysis. All the diaphragms exhibited exceptional alkali resistance, with weight changes of less than 1 % in a 25 to 30 wt% KOH solution. Additionally, permeability tests indicated that permeability decreased as polymer content increased. Electrochemical evaluations revealed that the 20 wt% polymer content diaphragm achieved the best performance, delivering 188.7 mA/cm². This study confirms the potential of using these diaphragms in efficient and sustainable alkaline water electrolysis systems.
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- 2024
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39. Effect of solution flow rate on the fabrication of outer surface selective layer hollow fiber membranes for dye rejection
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Wijaya, Gede Herry Arum, Kwon, Hyun Woong, Park, Jun Ho, Lee, Dong Jun, Im, Kwang Seop, and Nam, Sang Yong
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Various industries, such as food, petrochemicals, and pharmaceuticals, have recognized the importance of separation technologies for large molecules such as dye. A thin polyamide layer is commonly used in thin film composite membranes for separation applications, but fabricating a polyamide selective layer on hollow fiber (HF) membranes remains challenging. This research focuses on producing polyamide-based HF membranes by circulating aqueous and organic solutions during interfacial polymerization. By varying the solution flow rate, the dye rejection performance was investigated concerning morphology, polyamide thickness, mechanical properties, and hydrophilicity. All generated membranes consistently rejected over 98 % of congo red dye, with the highest rejection rate for methyl orange reaching approximately 92 %. The most efficient membranes were produced with an aqueous solution flow rate of 180 ml/min and an organic solution flow rate of 220 ml/min. These membranes exhibited notable ethanol permeance, with rejection rates of 99.75 % for congo red and 91.68 % for methyl orange. Additionally, they show promise for application in reverse osmosis processes for salt removal.
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- 2024
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40. Flavin Mononucleotide-Mediated Formation of Highly Electrically Conductive Hierarchical Monoclinic Multiwalled Carbon Nanotube-Polyamide 6 Nanocomposites.
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Minsuk Park, Seulki Yoon, Junmo Park, No-Hyung Park, and Sang-Yong Ju
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- 2021
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41. Long-term Comparison of Robotic and Laparoscopic Gastrectomy for Gastric Cancer A Propensity Score-weighted Analysis of 2084 Consecutive Patients.
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Ho-Jung Shin, Sang-Yong Son, Bo Wang, Chul Kyu Roh, Hoon Hur, and Sang-Uk Han
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Objective: To compare long-term outcomes between robotic and LG approaches using propensity score weighting based on a generalized boosted method to control for selection bias. Summary of Background Data: Minimally invasive surgical approaches for GC are increasing, yet limited evidence exists for long-term outcomes of robotic gastrectomy (RG). Methods: Patients (n ¼ 2084) with GC stages I-III who underwent LG or RG between 2009 and 2017 were analyzed. Generalized boosted method was used to estimate a propensity score derived from all available preoperative characteristics. Long-term outcomes were compared using the adjusted KaplanMeier method and the weighted Cox proportional hazards regression model. Results: After propensity score weighting, the population was balanced. Patients who underwent RG showed reduced blood loss (16 mL less, P ¼ 0.025), sufficient lymph node harvest from the initial period, and no changes in surgical outcomes over time. With 52-month median follow-up, no difference was noted in 5-year overall survival in unweighted [91.5% in LG vs 94% in RG; hazard ratio (HR), 0.71; 95% confidence interval (CI), 0.46–1.1; P ¼ 0.126] and weighted populations (94.2% in LG vs 93.2% in RG; HR, 0.88; 95% CI, 0.52–1.48; P ¼ 0.636). There were no differences in 5-year recurrence-free survival (RFS), with unweighted 5-year RFS of 95.4% for LG and 95.2% for RG (HR, 0.95; 95% CI, 0.55–1.64; P ¼ 0.845) and weighted 5-year RFS of 96.3% for LG and 95.3% for RG (HR, 1.24; 95% CI, 0.66–2.33; P ¼ 0.498). Conclusions: After balancing covariates, RG demonstrated reliable surgical outcomes from the beginning. Long-term survival after RG and LG for GC was similar. Objective: To compare long-term outcomes between robotic and LG approaches using propensity score weighting based on a generalized boosted method to control for selection bias. Summary of Background Data: Minimally invasive surgical approaches for GC are increasing, yet limited evidence exists for long-term outcomes of robotic gastrectomy (RG). Methods: Patients (n ¼ 2084) with GC stages I-III who underwent LG or RG between 2009 and 2017 were analyzed. Generalized boosted method was used to estimate a propensity score derived from all available preoperative characteristics. Long-term outcomes were compared using the adjusted KaplanMeier method and the weighted Cox proportional hazards regression model. Results: After propensity score weighting, the population was balanced. Patients who underwent RG showed reduced blood loss (16 mL less, P ¼ 0.025), sufficient lymph node harvest from the initial period, and no changes in surgical outcomes over time. With 52-month median follow-up, no difference was noted in 5-year overall survival in unweighted [91.5% in LG vs 94% in RG; hazard ratio (HR), 0.71; 95% confidence interval (CI), 0.46–1.1; P ¼ 0.126] and weighted populations (94.2% in LG vs 93.2% in RG; HR, 0.88; 95% CI, 0.52–1.48; P ¼ 0.636). There were no differences in 5-year recurrence-free survival (RFS), with unweighted 5-year RFS of 95.4% for LG and 95.2% for RG (HR, 0.95; 95% CI, 0.55–1.64; P ¼ 0.845) and weighted 5-year RFS of 96.3% for LG and 95.3% for RG (HR, 1.24; 95% CI, 0.66–2.33; P ¼ 0.498). Conclusions: After balancing covariates, RG demonstrated reliable surgical outcomes from the beginning. Long-term survival after RG and LG for GC was similar. [ABSTRACT FROM AUTHOR]
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- 2021
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42. A Beam Angle Selection Method to Improve Plan Robustness Against Position Error in Intensity-Modulated Radiotherapy for Left-Sided Breast Cancer
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Ding, Zhen, Kang, Kailian, Yuan, Qingqing, Zhang, Wenjue, and Sang, Yong
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Purpose We report a dosimetric study in whole breast irradiation (WBI) of plan robustness evaluation against position error with two radiation techniques: tangential intensity-modulated radiotherapy (T-IMRT) and multi-angle IMRT (M-IMRT).Methods Ten left-sided patients underwent WBI were selected. The dosimetric characteristics, biological evaluation and plan robustness were evaluated. The plan robustness quantification was performed by calculating the dose differences (Δ) of the original plan and perturbed plans, which were recalculated by introducing a 3-, 5-, and 10-mm shift in 18 directions.Results M-IMRT showed better sparing of high-dose volume of organs at risk (OARs), but performed a larger low-dose irradiation volume of normal tissue. The greater shift worsened plan robustness. For a 10-mm perturbation, greater dose differences were observed in T-IMRT plans in nearly all directions, with higher ΔD98%, ΔD95%, and ΔDmeanof CTV Boost and CTV. A 10-mm shift in inferior (I) direction induced CTV Boost in T-IMRT plans a 1.1 (ΔD98%), 1.1 (ΔD95%), and 1.7 (ΔDmean) times dose differences greater than dose differences in M-IMRT plans. For CTV Boost, shifts in the right (R) and I directions generated greater dose differences in T-IMRT plans, while shifts in left (L) and superior (S) directions generated larger dose differences in M-IMRT plans. For CTV, T-IMRT plans showed higher sensitivity to a shift in the R direction. M-IMRT plans showed higher sensitivity to shifts in L, S, and I directions. For OARs, negligible dose differences were found in V20of the lungs and heart. Greater ΔDmaxof the left anterior descending artery (LAD) was seen in M-IMRT plans.Conclusion We proposed a plan robustness evaluation method to determine the beam angle against position uncertainty accompanied by optimal dose distribution and OAR sparing.
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- 2024
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43. Deterministic transfer of thin carbon nanotube film
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Park, Minsuk and Ju, Sang‐Yong
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Although successfully implemented for optoelectronic devices of two‐dimensional materials, deterministic transfer for thin single‐walled carbon nanotube (SWNT) film has not been realized. Herein, we report a transfer method of few hundreds nanometer‐thick SWNT film to a desired prepatterned substrate position with few micrometer precision. This method comprises poly(methyl methacrylate) (PMMA)‐coated SWNT film, creating surface anisotropy on both sides for SWNT film transfer, and two sets of translators manipulating the film to desired position and angle. Especially, adsorption and desorption of PMMA‐coated SWNT film by each translator were modulated by use of interfacial water which not only promotes PMMA side to the transient sample loader via water capillary and releases the final substrate with capillary assisted sliding. Successful transfer of thin SWNT film with few tens of micrometer precision was achieved and will be beneficial for the preparation of high‐end optoelectronic devices. Although successfully implemented for two‐dimensional materials based optoelectronic devices, deterministic transfer for thin SWNT film has not been realized. Herein, we report a transfer method of few tens of nanometer‐thick SWNT film to a desired prepatterned substrate position.
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- 2022
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44. Design and Analysis of Permanent-Magnet Vernier Machine for Direct-Driven Wind Power Generator Considering Pole-Slot Combinations
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Kim, Hyung-Woo, Kang, Seung-Gu, Jung, Sang-Yong, and Yeo, Han-Kyeol
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Wind power turbines have increasingly attracted attention as a renewable energy source. Gearboxes in wind turbines reduce their efficiency, require periodic maintenance, and result in gearbox failure. Consequently, direct-driven generators with a high torque density have emerged as an alternative because they transmit the high torque of the wind turbine directly. Permanent-magnet vernier machines (PMVMs) possess a simple and robust structure and significantly high torque density at low speeds. Although various topologies and pole-slot combinations of PMVMs have been considered to enhance their performance, studies on fractional-slot distributed-winding PMVMs (FSDW PMVMs) remain limited compared with those on fractional-slot concentrated-winding PMVMs (FSCW PMVMs). In this study, we designed eight models, including permanent magnet synchronous machines (PMSMs), FSDW, and FSCW PMVMs for direct-driven wind power generators. Their performances in terms of torque density, torque ripple, losses, and power factor were compared and verified using finite element analysis. The FSDW PMVM was proposed as the best model for direct-driven wind power generators based on the torque density, torque ripple, and possibility of performance improvement.
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- 2022
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45. Quantum electron liquid and its possible phase transition
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Kim, Sunghun, Bang, Joonho, Lim, Chan-young, Lee, Seung Yong, Hyun, Jounghoon, Lee, Gyubin, Lee, Yeonghoon, Denlinger, Jonathan D., Huh, Soonsang, Kim, Changyoung, Song, Sang Yong, Seo, Jungpil, Thapa, Dinesh, Kim, Seong-Gon, Lee, Young Hee, Kim, Yeongkwan, and Kim, Sung Wng
- Abstract
Purely quantum electron systems exhibit intriguing correlated electronic phases by virtue of quantum fluctuations in addition to electron–electron interactions. To realize such quantum electron systems, a key ingredient is dense electrons decoupled from other degrees of freedom. Here, we report the discovery of a pure quantum electron liquid that spreads up to ~3 Å in a vacuum on the surface of an electride crystal. Its extremely high electron density and weak hybridization with buried atomic orbitals show the quantum and pure nature of the electrons, which exhibit a polarized liquid phase, as demonstrated by our spin-dependent measurement. Furthermore, upon enhancing the electron correlation strength, the dynamics of the quantum electrons change to that of a non-Fermi liquid along with an anomalous band deformation, suggestive of a transition to a hexatic liquid crystal phase. Our findings develop the frontier of quantum electron systems and serve as a platform for exploring correlated electronic phases in a pure fashion.
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- 2022
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46. Urinary 1-aminopyrene level in Koreans as a biomarker for the amount of exposure to atmospheric 1-nitropyrene
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Ochirpurev, Bolormaa, Eom, Sang-Yong, Toriba, Akira, Kim, Yong-Dae, and Kim, Heon
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1-Nitropyrene (1-NP) is a major nitro-polycyclic aromatic hydrocarbon (nitro-PAH), and a common constituent in diesel exhaust particles (DEPs). Absorbed 1-nitropyrene is partly metabolized to 1-aminopyrene and excreted in urine. Recently, the number of diesel cars has been increasing, which could be a major cause of air pollution, resulting elevated levels of traffic-related DEPs around cities. The aim of this study was to investigate the usability of 1-aminopyrene (1-AP) as a biomarker for DEP exposure by examining the association between urinary 1-AP concentration and the amount of exposure to atmospheric 1-NP. The study subjects included 65 individuals who work on vehicular roads or bus terminals. Their 24 h urine samples were collected, and atmospheric air was sampled using a personal air sampler for 24 h. Urinary 1-AP and atmospheric nitro-PAH levels were measured using a high-pressure liquid chromatography-fluorescence detector (HPLC-FD). The average urine 1-AP concentration was 0.334 pg/g creatinine. Urinary 1-AP levels were significantly correlated with 1-NP level exposure (r = 0.385, p= 0.002) but not with the other nitro-PAHs. When the subjects were classified into high-and low-exposure groups, a significant association was only found in the high exposure group (r = 0.357, p= 0.045). In conclusion, there was a significant correlation between 1-NP exposure and urinary 1-AP concentration; therefore, urinary 1-AP level could be used as an exposure biomarker for DEP.
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- 2022
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47. Anion Exchange Composite Membranes Composed of Quaternary Ammonium-Functionalized Poly(2,6-dimethyl-1,4-phenylene oxide) and Silica for Fuel Cell Application.
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Vijayakumar, Vijayalekshmi, Son, Tae Yang, Im, Kwang Seop, Chae, Ji Eon, Kim, Hyoung Juhn, Kim, Tae Hyun, and Nam, Sang Yong
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- 2021
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48. Structure-based molecular docking approach for identifying S‑formylglutathione hydrolase from Sphingobium chungbukense
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Lee, Jin-Pyo, Shin, Woo-Ri, Ahn, Gna, Um, Hyun-Ju, Kim, Young-Chang, Kim, Sang Yong, Ahn, Ji-Young, and Kim, Yang-Hoon
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Object: We isolated S-formylglutathione hydrolase (scSFH) from Sphingobium chungbukensestrain KCTC2955 and expressed it in Escherichia coli. The extracted scSFH showed activity toward p-nitrophenyl butyrate (p-NB), and a protein–substrate interaction was confirmed through 3D molecular docking simulation. Methods: The DNA sequence of the cloned scSFH gene (900 bp) has an open reading frame encoding 300 amino acids with a predicted molecular mass of 32.82 kDa; the sequence contains Ser-His-Asp conserved in the active site and a GHSMGG motif. The cloned scSFH gene successfully overproduced scSFH protein under the T7 promoter of the expression vectors pET21a and pGEX4T-1 in E. coliBL21(DE3). We analyzed E. coli-expressed scSFH protein for esterase activity using p-NB as a substrate. Furthermore, we confirmed the interaction between the scSFH protein and p-NB substrate. Results: The scSFH protein of the SFH family was overexpressed in E. coliBL21(DE3) and purified using affinity Ni–NTA agarose resin. The activity of purified scSFH against p-NB was 6.87 mg L
−1 for Km and 131.16 mg L−1 protein min−1 for Vmax . Additionally, we confirmed that the serine residue of the GHSMGG motif in the obtained protein interacts with p-NB through molecular docking prediction by the molecular operating environment. Conclusion: We identified a novel scSFH gene from S. chungbukenseand overexpressed it in E. coli. The recombined scSFH protein showed activity toward p-NB, and the interaction was confirmed through 3D molecular docking prediction. This research could be applied to identify new genes and confirm their functions.- Published
- 2021
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49. Serial Observations of Muscle and Fat Mass as Prognostic Factors for Deceased Donor Liver Transplantation.
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Jisun Lee, Woo Kyoung Jeong, Jae-Hun Kim, Jong Man Kim, Tae Yeob Kim, Gyu Seong Choi, Choon Hyuck Kwon, David, Jae-Won Joh, and Sang-Yong Eom
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- 2021
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50. Prognostic value of hypocholesterolemia in patients with gastric cancer.
- Author
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Shin, Ho-Jung, Roh, Chul-Kyu, Son, Sang-Yong, Hoon, Hur, and Han, Sang-Uk
- Abstract
According to previous studies, low serum total cholesterol (TC) is associated with higher cancer incidence and mortality. However, the prognostic implications of preoperative TC in patients with gastric cancer (GC) remain to be determined. A total of 1251 patients with GC, who underwent radical gastrectomy between 2005 and 2008, were recruited. Propensity score weighting (PSW) based on a generalized boosted method (GBM) was used to control for selection bias. After balancing the preoperative and operative covariates, low TC was associated with high incidence of complications (severe complication rate: 15.2% (Low TC) vs. 4.7% (Normal TC) vs 5.5% (High TC); p = 0.004). In multivariable analysis, lowering TC was associated with poor OS and RFS in weighted population. [OS: hazard ratio (HR) = 0.92; 95% CI = 0.867–0.980; P = 0.009 and RFS: HR = 0.93; 95% CI = 0.873–0.988; P = 0.02]. Preoperative TC is a useful predictor of postoperative survival and postoperative complications in patients with stage I–III GC and may help to identify high-risk patients for rational therapy, including nutritional support, and timely follow-up. [ABSTRACT FROM AUTHOR]
- Published
- 2021
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